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  • 1995-1999  (1,023)
  • 1999  (1,023)
  • General Chemistry  (750)
  • Analytical Chemistry and Spectroscopy  (132)
  • gene expression  (79)
  • Amino acids  (73)
  • Biochemistry and Biotechnology
  • Engineering
  • Nuclear reactions
  • Organic Chemistry
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Years
  • 1995-1999  (1,023)
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Determination of the protooncogene ets-2 gene transcript in human brain at the atto-gram-level by the use of competitive RT/PCR (1999)
    Springer
    Amino acids 16 (1999), S. 13-19 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; RT/PCR ; Protooncogene ; ets-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Protooncogenes (PO) play a crucial role for brain biology and pathology. Only the concerted action of protooncogenes enables normal brain development. The reliable and sensitive quantification of brain PO is still holding centre stage in neurobiological research. The aim of our study was therefore the determination of PO in minute amounts of brain areas. For this purpose we decided to apply the most sensitive detection principle of competitive reverse transcriptase polymerase chain reaction using capillary electrophoresis and laser-induced fluorescence detection. We selected the PO ets-2 for our studies as this transcription factor was shown to be involved in neurodegenerative disease. As little as 10ng of total RNA each were extracted from 5 different regions of human postmortem brain and used in the assay system. Our results revealed that the ets-2 gene transcript was detectable at the atto-gram level in the brain (54.5 ± 17.7 ag/ 10 ng RNA in the occipital lobe, 34.2 ± 7.5 in temporal lobe, 40.2 ± 15.6 in the frontal lobe, 31.4 ± 15.7 in the cerebellum, and undetectably low in the parietal lobe). This is the first report at this sensitivity level providing neurobiology with a powerful analytical tool.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01318881
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  • 2
    Electronic Resource
    Electronic Resource
    Changes in plasma taurine levels after different endurance events (1999)
    Springer
    Amino acids 16 (1999), S. 71-77 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Taurine ; Marathon ; Endurance exercise
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The sulphonated amino acid taurine increased significantly in the plasma of trained athletes after three endurance exercises of different duration and intensity, a 90 min run on a treadmill at 75% of an individual's VO2 peak, a Marathon, 42.2km and a 100km run, by 19%, 77% and 36%, respectively. Such results indicated that the speed at which the exercise is per formed, referred to as the intensity, rather than the duration of the exercise, correlated with the elevated taurine levels possibly indicating its release from muscle fibres. The plasma amino acid pool decreased significantly in relationship with the duration of the exercise, caused by their utilisation for glucogenesis. The possible sources of the increased plasma taurine are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01318886
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of non proteinogenic dipeptides by asymmetric hydrogenation (1999)
    Springer
    Amino acids 17 (1999), S. 369-376 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Non-proteinogenic dipeptides ; Dehydrodipeptides ; Diastereoselectivity ; N-Boc-Dehydroamino acids ; Asymmetric hydrogenation ; Chiral rhodium catalysts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary N-Boc protected non-proteinogenic dipeptides with D,L-and L,L-configuration were prepared by catalytic asymmetric hydrogenation of the corresponding dehydrophenylalanyl-(L)-phenylalanine derivatives. The configuration of the new stereogenic centre depends first of all on the catalyst configuration and is less influenced by the substrate configuration. Diastereomeric excesses in the range of 80–96% de could be increased up to 99% by recrystallization. Analytical data of selected new compounds are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361662
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  • 4
    Electronic Resource
    Electronic Resource
    Production of polyclonal antibodies towards the immunodetection of insecticide phosalone (1999)
    Springer
    Amino acids 17 (1999), S. 377-389 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Polyclonal antibodies ; Phosalone ; Immunodetection ; Hapten synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Hapten synthesis for the production of specific insecticide phosalone polyclonal antibodies was carried out starting from an intermediate of the phosalone synthesis, 6-chloro-2-benzoxazolone1. Two haptens containing different spacers have been prepared: N-5-carboxypentyl-6-chloro-2-benzoxazolone7 and N-(2-oxo-3-aza-5-carboxypentyl)-6-chloro-2-benzoxazolone12. Each of these two haptens conjugated to bovine serum albumine (BSA) was used to immunize four rabbits. Immunoassays of phosalone were performed with ELISA using solid-phase bound hapten thyroglobulin conjugate and horseradish peroxidase labelled goat antirabbit IgG. The more sensitive response was observed when the antiserum obtained from the rabbit immunized with the hapten-BSA conjugate containing the N-2-oxo-3-aza-5-carboxypentyl spacer was in competition with the same hapten coupled to thyroglobulin. An identical response was obtained under the same conditions when using benzoxazolone instead of phosalone as competitor, showing a good recognition of the specific aromatic part of the organophosphate insecticide phosalone. Reduction of coating conjugate concentration (from 2 to 0.05μg/well) and also the use of heterologous coating protein instead of homologous did improve the sensitivity, resulting in a concentration of phosalone required to inhibit binding by 50% of 2 mg/l and a detection limit of 0.02 mg/l.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361663
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  • 5
    Electronic Resource
    Electronic Resource
    Plasma amino acid levels after carbon tetrachloride induced acute liver damage. A dose-response and time-response study in rats (1999)
    Springer
    Amino acids 16 (1999), S. 1-11 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Liver ; Hepatic damage ; Carbon tetrachloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aims of the present study were to assess the changes of individual plasma amino acid levels in relation (1) to the severity of liver damage and (2) to the process of liver recovery. Acute liver injury was induced by an intragastric administration of CCl4 diluted in olive oil in doses of 2, 4 and /or 6 g of CCl4 per kg b.w. The control rats received olive oil only. Animals were sacrificed at 16, 24, 48 and 96 hours after treatment. The severity of liver injury was assessed by histological examination, by changes in ALT and AST in the blood plasma and by changes in liver weight. Statistical analysis was carried by ANOVA, p 〈 0.05 was considered significant. The Spearman rank correlation coefficient was used as a measure of the degree of linear relationship between variable and dose. In the period of the development of acute liver damage, i.e. at 16 and 24 hours after treatment, an increase in blood plasma amino acid levels and positive correlations with the dose of CCl4 were observed for most individual amino acids. The only exception was arginine which decreased in a dose dependent manner. At a phase of liver recovery, i.e. at 48 and 96 hours after CCl4 treatment, the concentrations of some individual amino acids decreased below the control values. The negative correlation with the dose of CCl4 occurred for taurine and isoleucine (at 48 hours) and taurine, threonine, valine, methionine, isoleucine and leucine (at 96 hours).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01318880
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  • 6
    Electronic Resource
    Electronic Resource
    Fatty acids and glycerol or lactate are required to induce gluconeogenesis from alanine in isolated rabbit renal cortical tubules (1999)
    Springer
    Amino acids 16 (1999), S. 41-58 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Alanine ; Fatty acids ; Glutamine and glutamate synthesis ; Glycerol and lactate metabolism ; Malate-aspartate shuttle ; Rabbit kidney-cortex tubules ; Renal gluconeogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In isolated rabbit renal cortical tubules, glucose synthesis from 1 mM alanine is negligible, while the amino acid is metabolized to glutamine and glutamate. The addition of 0.5 mM octanoate plus 2 mM glycerol induces incorporation of [U-14C]Alnine into glucose and decreases glutamine synthesis, whereas oleate and palmitate in the presence of glycerol are less potent than octanoate. Gluconeogenesis is also significantly accelerated when glycerol is substituted by lactate. In view of an increase in14CO2 fixation and elevation of both cytosolic and mitochondrial NADH/NAD+ ratios, the activation of glucose formation from alanine upon the addition of glycerol and octanoate is likely due to (i) stimulation of pyruvate carboxylation, (ii) increased availability of NADH for glyceraldehyde-3-phosphate dehydrogenase and (iii) elevation of mitochondrial redox state causing a diminished provision of ammonium for glutamine synthesis. The induction of gluconeogenesis in the presence of alanine, glycerol and octanoate is not related to cell volume changes. The results presented in this paper show the importance of free fatty acids and glycerol for regulation of renal gluconeogenesis from alanine. The possible physiological significance of the data is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01318884
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  • 7
    Electronic Resource
    Electronic Resource
    Substituted 4-hydroxyproline di- and tri-peptides as cytotoxic agents (1999)
    Springer
    Amino acids 16 (1999), S. 79-89 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Anti-neoplastic amino acids ; Purine and DNA synthesis inhibitors ; PRPP amido transferase and IMP dehydrogenase inhibitors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 4-Hydroxyproline di- and tri-peptides and N-cbz-hydroxypropylglycinamides were observed to be potent cytotoxic agents against the growth of suspended single cells, L-1210, Tmolt3, and HeLa-S3. The agents were not as potent against the growth of cultured solid tumor cells. Selected derivatives were investigated for their mode of action in Tmolt3 leukemia cells. The compounds selectively inhibited DNA synthesis at 50 and 100smM. The target site of action of the agents appeared to be the purinede novo pathway with marked inhibition of the activities of the two regulatory enzymes of the pathway, i.e. PRPP amido-transferase and IMP dehydrogenase. d[NTP] pools were reduced by the agents consistent with their overall reduction of DNA synthesis. Other marginally inhibited targets of the agents were r-RNA polymerase and TMP-kinase activities. The DNA molecule itself did not appear to be a target of these agents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01318887
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  • 8
    Electronic Resource
    Electronic Resource
    Molecular cloning and expression analyses of mitochondrial and plastidic isoforms of cysteine synthase (O-acetylserine(thiol)lyase) fromArabidopsis thaliana (1999)
    Springer
    Amino acids 16 (1999), S. 113-131 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Targeting ; Mitochondria ; Chloroplasts ; Cysteine synthase ; Transit peptide ; Transgenic plants ; Processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cysteme synthase, the key enzyme for fixation of inorganic sulfide, catalyses the formation of cysteine from O-acetylserine and inorganic sulfide. Here we report the cloning of cDNAs encoding cysteine synthase isoforms fromArabidopsis thaliana. The isolated cDNA clones encode for a mitochondrial and a plastidic isoform of cysteine synthase (O-acetylserine (thiol)-lyase, EC 4.2.99.8), designated cysteine synthase C (AtCS-C, CSase C) and B (AtCS-B; CSase B), respectively.AtCS-C andAtCS-B, having lengths of 1569-bp and 1421-bp, respectively, encode polypeptides of 430 amino acids (∼45.8 kD) and of 392 amino acids (∼ 41.8 kD), respectively. The deduced amino acid sequences of the mitochondrial and plastidic isoforms exhibit high homology even with respect to the presequences. The predicted presequence of AtCS-C has a N-terminal extension of 33 amino acids when compared to the plastidic isoform. Northern blot analysis showed thatAtCS-C is higher expressed in roots than in leaves whereas the expression ofAtCS-B is stronger in leaves. Furthermore, gene expression of both genes was enhanced by sulfur limitation which in turn led to an increase in enzyme activity in crude extracts of plants. Expression of theAtCS-B gene is regulated by light. The mitochondrial, plastidic and cytosolic (Hesse and Altmann, 1995) isoforms of cysteine synthase ofArabidopsis are able to complement a cysteine synthasedeficient mutant ofEscherichia coli unable to grow on minimal medium without cysteine, indicating synthesis of functional plant proteins in the bacterium. Two lines of evidence proved thatAtCS-C encodes a mitochondrial form of cysteine synthase; first, import ofin vitro translation products derived from AtCS-C in isolated intact mitochondria and second, Western blot analysis of mitochondria isolated from transgenic tobacco plants expressing AtCS-C cDNA/c-myc DNA fusion protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01321531
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  • 9
    Electronic Resource
    Electronic Resource
    Unusual amino acids VIII. Asymmetric hydrogenation of some heteroaryl-N-CBZ and N-BOC aminocinnamic acid derivatives (1999)
    Springer
    Amino acids 16 (1999), S. 21-27 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Non-proteinogenic optically active amino acids ; Dehydroamino acids ; Chiral rhodium catalysts ; Asymmetric hydrogenation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary (Z)-α-[(Benzyloxy)- or (tert.-butyloxy)carbonylamino]-β (thienyl)-or (furyl)-acrylic acids and their esters were prepared by known methods and hydrogenated to the corresponding optically active alanine derivatives with optical yields in the range of 58–93% ee using the cationic rhodium complex of “PROPRAPHOS”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01318882
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  • 10
    Electronic Resource
    Electronic Resource
    Contribution of serum albumin to the transport of orally administered L-tryptophan into liver of rats with L-tryptophan depletion (1999)
    Springer
    Amino acids 16 (1999), S. 29-39 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; L-Tryptophan ; Serum albumin ; Transport ; L-Tryptophan depletion ; α-Methyl-DL-tryptophan ; Analbuminemic rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The role of serum albumin in the transport of orally administered L-tryptophan (Trp) into rat tissues was examined using analbuminemic and Sprague-Dawley (SD) rats with and without a-methyl-DL-tryptophan (AMT)-induced Trp depletion. Trp was orally administered to rats 16h after AMT or 0.85% NaCl administration, when liver tryptophan 2,3-dioxygenase and protein synthetic activities in AMT-treated rats were similar to those of 0.85% NaCl-treated rats. After oral Trp administration, regardless of the presence or absence of Trp depletion, free serum Trp concentrations were similar in the analbuminemic and SD rats, while total serum Trp concentrations were lower in analbuminemic rats than in SD rats. Although liver, brain, and muscle Trp concentrations after oral Trp administration under Trp depletion were lower in analbuminemic rats than in SD rats, the ratio of the liver Trp concentration in analbuminemic rats to that in SD rats was smaller than that of the brain or muscle Trp concentration. These results suggest that variations in serum albumin levels could affect the transport of orally administered Trp into the liver of rats with Trp depletion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01318883
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  • 11
    Electronic Resource
    Electronic Resource
    A comparison of15N proline and13C leucine for monitoring protein biosynthesis in the skin (1999)
    Springer
    Amino acids 16 (1999), S. 107-111 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Tissue protein synthesis ; Stable isotope amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The tracers L15N-proline and L(1-13C)-leucine were used to explore the synthesis of skin proteins in vivo in rabbits. They orally received a single dose containing an equimolecular mixture of L(1-13C)-leucine and L15N-proline. The changes in the amounts of these tracers in blood and skin were monitored for a total of 8 h. The data showed the appearance of the two tracers in blood within 15 min and their clearance in 8h. They were both rapidly (15 min) incorporated into skin proteins, but more proline was incorporated than leucine. We therefore consider L15N-proline to be a better tracer than L(1-13C)-leucine for studying protein metabolism in the skin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01321530
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  • 12
    Electronic Resource
    Electronic Resource
    Kainic acid (KA)-induced seizures in Sprague-Dawley rats and the effect of dietary taurine (TAU) supplementation or deficiency (1999)
    Springer
    Amino acids 16 (1999), S. 133-147 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Taurine ; Kainic acid ; Epilepsy ; Anticonvulsants ; Neuroprotection ; Excitatory amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Male Sprague-Dawley rats received TAU supplementation (1.5% in drinking water) or TAU deficient diets for 4 weeks to test for a possible neuroprotective role of TAU in KA-induced (10 mg/kg s.c.) seizures. TAU supplementation significantly increased serum and hippocampal TAU levels, but not TAU content in temporal cortex or striatum. TAU deficient diets did not attenuate serum or tissue TAU levels. Dietary TAU supplementation failed to decrease the number or latency of partial or clonic-tonic seizures or wet dog shakes, whereas a TAU deficient diet decreased the number of clonictonic and partial seizures. This study does not support previous observations of an anticonvulsant effect of TAU against KA-induced seizures. KAtreatment decreasedα 2-adrenergic receptor binding sites and TAU content in the temporal cortex across all dietary treatment groups, supporting previous evidence of severe KA-induced damage and neuronal loss in this brain region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01321532
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  • 13
    Electronic Resource
    Electronic Resource
    Enzymatic resolution of amino acids via ester hydrolysis (1999)
    Springer
    Amino acids 16 (1999), S. 191-213 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Enzymatic resolution ; Ester hydrolysis ; Proteases ; Lipases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present review outlines recent examples of enzyme-based resolution procedures for amino acids via the hydrolysis of their esters. The resolutions have been achieved by using proteases (α-chymotrypsin, subtilisin and other microbial proteases, and sulfhydryl proteases of plant origin) and lipases. Relevant work utilizing yeast and other microbial cells is also included.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01388169
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  • 14
    Electronic Resource
    Electronic Resource
    Syntheses of optically active 2-amino-4-oxobutyric acid and N,O-protected derivatives (1999)
    Springer
    Amino acids 16 (1999), S. 251-272 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Unusual amino acids ; Aspartic acidβ-semialdehyde ; Aspartaldehyde ; 2-Amino-4-oxobutyric acid ; Enantioselective synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Strategies for the synthesis of optically active aspartaldehyde derivatives are reviewed. Most of them are using the chiral pool: allylglycine or naturally occurring homoserine, aspartic acid or methionme and side chain modifications. This will be developed in the first part. Some other original routes are also displayed in the second part. Different aspects of each strategy are discussed: the nature and number of steps, the problem of protecting groups, the price and availability of starting materials. Some synthetic applications of such interesting chiral synthons are shown in the last part.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01388171
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  • 15
    Electronic Resource
    Electronic Resource
    Asymmetric hydrogenation of dehydrodipeptide esters bearing different protective groups (1999)
    Springer
    Amino acids 16 (1999), S. 391-401 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Dipeptide derivatives ; Non-proternogenic optically active dipeptide esters ; Dehydrodipeptides ; Chiral rhodium catalysts ; Asymmetric hydrogenation ; Diastereoselectivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary N-[(Z)-N-Benzoyl- orN-Boc-(2-fluorophenyl)dehydroalanyl]-(R)-or (S)-phenylalanine esters were synthesized and hydrogenated to give the corresponding dipeptide derivatives with optical yields in the range of 53–87%de using the cationic rhodium complexes of PROPRAPHOS and BPPM. The efficiency of chiral diphosphine ligands as well the effect of the chiral center in the substrate on the catalytic asymmetric induction was studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01388178
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  • 16
    Electronic Resource
    Electronic Resource
    Spectral analysis of a series of partially protected and deprotected tetrapeptides, analogues of AS-I phytotoxin (1999)
    Springer
    Amino acids 16 (1999), S. 403-413 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Phytotoxin AS-I analogues ; FAB ; PD ; ESI mass spectrometry ; 1H,13C and 2D NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A series of six tetrapeptides, analogues of AS-I phytotoxin, pathogenic to sunflower, have been synthesized either in solution and/or by solid phase methods and have been tested for phytotoxic activity in various plants and cytotoxic activity in three cancer cell lines. These peptides were identified as model compounds by fast atom bombardment (FAB), plasma desorption (PD), electrospray ionization (ESI) mass spectrometry and by1H,1H-1H,13C and1H-13C NMR. The data presented show that in protected tetrapeptides the molecular ion was easily identified whereas some difficulties appeared with the fully deprotected peptides. NMR spectra are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01388179
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  • 17
    Electronic Resource
    Electronic Resource
    Synthesis and anti-phlogistic potency of some new non-proteinogenic amino acid conjugates of “Diclofenac” (1999)
    Springer
    Amino acids 16 (1999), S. 425-440 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Diclofenac ; Anti-phlogistics ; Non-proteinogenic amino acids ; Voltaren®. Thionation ; Cyclo-oxygenase inhibitors ; Ulcerogenic gastritis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In search for more potent, particularly less ulcerogenic gastritis that hopefully replace the universal NSAID “Diclofenac”, (2-[(2,6-di-chlorophenyl)amino]-phenylacetic acid, C.A.S. 15307-86-5), twelve new non-proteinogenic amino acid conjugates of the drug, namely that of sarcosine,β-alanine, D-leucine and D-phenylalanine, were synthesized and biologically screened for their anti-inflammatory, analgesic and ulcerogenic activity in rats. “Diclofenac” amino acid esters (IIa-d), were synthesizedvia the corresponding HOSu or HOBt active esters. Alkaline hydrolysis (NaOH) followed by acidification (KHSO4) or thioamide formation (Lawsson's Reagent, C.A.S. 19172-47-5), afforded the corresponding free acids IIIa-d or the thioamides IVa-d respectively. Interestingly, in contrary to the parent “Diclofenac”, the synthesized candidates (except IIId), were entirly nonulcerogenic in rats. Further, they considerably retained a generelized anti-phlogistic activity. The major “Diclofenac” irritating gastric side effect was thus eliminated. Particularly, the sarcosine conjugate IIa and its thiomimic IVa exhibit promising therapeutic perspectives.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01388181
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  • 18
    Electronic Resource
    Electronic Resource
    Gender-related differences in polyamine oxidase activity in rat tissues (1999)
    Springer
    Amino acids 17 (1999), S. 139-148 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Polyamine oxidase ; Polyamines ; Gender ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Variations in level of polyamines and their related enzymes are frequently observed in response to some treatments which affect in a different way male and female. The possibility of a gender-related difference in the oxidation of polyamines was investigated in rats by measuring the activity of polyamine oxidase, a ubiquitous enzyme of vertebrate tissues, which transforms spermine into spermidine and spermidine into putrescine. The study was carried out on thymus, spleen, kidney and liver of young rats of both sexes, and female rats showed a lower polyamine oxidase activity than male rats in all the tissues. We also found higher values of spermidine acetylation in female than male rats in thymus and liver. Owing to these gender-related differences, a higher spermidine N-acetyltransferase/ polyamine oxidase ratio was found in female than in male rats. A second gender-related difference was a higher spermidine/spermine ratio in female than in male, the only exception being the thymus. These basal differences possibly account for the gender-related differences of polyamine metabolic enzyme activities in response to some treatments, including drugs or hormones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361877
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  • 19
    Electronic Resource
    Electronic Resource
    Amino acids and osmolarity in honeybee drone haemolymph (1999)
    Springer
    Amino acids 17 (1999), S. 195-205 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Apis mellifera ; Drones ; Osmolarity ; Age dependency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the haemolymph of honeybee drones, concentrations of free amino acids were higher than in worker haemolymph, with different relative proportions of individual amino acids. The overall concentration of free amino acids reached its highest level at the 5th day after adult drone emergence, and after the 9th day only minor changes in the concentration and distribution of free amino acids were observed. This coincides with the age when drones reach sexual maturity and change their feeding behaviour. Levels of essential free amino acids were high during the first 3 days of life and thereafter decreased. Osmolarity was lowest at emergence (334 ± 41 mOsm), increased until the age of 3 days (423 ± 32mOsm) and then stayed generally constant until the 16th day of life. Only 25-day-old drones had significantly higher osmolarity (532 ± 38 mOsm). The overall change in osmolarity during a drone's lifetime was about 40%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361882
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  • 20
    Electronic Resource
    Electronic Resource
    Novel glutathione analogues containing the dithiol and disulfide form of the Cys-Cys dyad (1999)
    Springer
    Amino acids 17 (1999), S. 257-265 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Conformational constraint ; Cyclic disulfides ; -Cys-Cys-peptides ; Dipeptide mimetics ; Dithiols ; Glutathione analogues
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The glutathione analogue γ-(H-Glu-OH)- -OH (5), containing the 8-membered disulfide ring- replacing the native -Cys-Gly fragment, has been synthesized and characterized together with its reduced dithiol form γ-(H-Glu-OH)-Cys-Cys-OH (6).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01366924
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  • 21
    Electronic Resource
    Electronic Resource
    Developmental aspects of polyamine-oxidizing enzyme activities in the mouse kidney. Effects of testosterone (1999)
    Springer
    Amino acids 17 (1999), S. 267-276 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Polyamine catabolism ; Polyamine oxidase ; Diamine oxidase ; Testosterone ; Mouse kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the present study developmental patterns of renal polyamineoxidizing enzymes polyamine oxidase (PAO) and diamine oxidase (DAO) in male and female ICR mice were demonstrated. The effects of testosterone (10μg/100g body weight) on renal PAO and DAO activities were also studied. The differences between sexes in both PAO and DAO activities were most clearly expressed in the immature kidney. At the age of 20 days PAO and DAO activities were 1.52 fold (p 〈 0.01) and 1.75 (p 〈 0.02) respectively higher in male mouse kidney than in female. Maturational processes reflected in significant increases in polyamine- oxidizing enzyme activities mainly in female mouse kidney, comparable with the gain in the kidney wet weight. Our data show that testosterone is able to influence renal PAO and DAO activities in addition to the well-known stimulation of polyamine biosynthesis. The hormonal effects were sex and age dependent. The influence of testosterone on renal PAO activity was mainly age dependent. The slight stimulation of renal PAO activity observed in 20- and 50-day old mice, 24h after testosterone administration, change with a decrease in the enzyme activity at the age of 70 days. The effects of testosterone on renal DAO activity were mainly sex dependent. Testosterone caused stimulation of DAO activity with a very close magnitude (nearly twice) in female mouse kidney, independently of the age of mice. In contrast, in male mice the hormone treatment resulted in a statistically significant increase in renal DAO activity at the age of 70 days (.1.3 fold, p 〈 0.05) only. It could be suggested that our data indicate the different contribution of renal PAO and DAO in androgen regulation of polyamine levels, depending on sex and the stage of the postnatal development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01366925
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  • 22
    Electronic Resource
    Electronic Resource
    Determination of the optical purity of threonine and hydroxyproline by capillary gas chromatography on a chiral stationary phase (1999)
    Springer
    Amino acids 17 (1999), S. 293-300 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Allohydroxyproline ; Allothreonine ; Chiral separation ; Chirasil-Val ; Hydroxyproline ; Threonine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Experimental conditions for the derivatization and resolution by GLC of all stereoisomers of threonine and 4-hydroxyproline are reported. Threonine was in two steps converted toN,O-bisisobutoxycarbonyl 2,2,2-trifluoroethyl ester derivatives, the second of which was performed under anhydrous conditions. As such the enantiomers could pairwise be separated by capillary gas chromatography on a Chirasil-Val column. SinceL- andD-threonine eluted much earlier than the corresponding allo forms, quantitative determination of the allothreonine content inD- orL-threonine down to the one percent level could be simply accomplished but also enantiomeric impurities could be determined. Unlike for threonine, the corresponding 4-hydroxyproline isomers could not all be resolved asN,O-bisisobutoxycarbonyl 2,2,2-trifluoroethyl esters on this column. Although diastereomers could still be separated, the allo pair cochromatographed and the resolution for theL- andD-isomers was low. Complete separation of the 4-hydroxyproline isomers could be accomplished asN,O-bisprotected isobutyl amides, the formation of which required three derivatization steps. These were used for the determination of allohydroxyproline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01366928
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  • 23
    Electronic Resource
    Electronic Resource
    Enhanced taurine release in cultured cerebellar granule cells in cell-damaging conditions (1999)
    Springer
    Amino acids 17 (1999), S. 323-334 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Taurine release ; Cerebellar granule cells ; Celldamaging conditions ; Glutamate receptors ; Veratridine ; Potassium stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The release of taurine from cultured cerebellar granule neurons was studied in different cell-damaging conditions, including hypoxia, hypoglycemia, ischemia, oxidative stress and in the presence of free radicals. The effects of both ionotropic and metabotropic glutamate receptor agonists on the release were likewise investigated. The release of [3H]taurine from the glutamatergic granule cells was increased by K+ (50mM) and veratridine (0.1 mM), the effect of veratridine being the greater. Hypoxia and ischemia produced an initial increase in release compared to normoxia but resulted in a diminished response to K. Hypoglycemia, oxidative stress and free radicals enhanced taurine release, and subsequent K− treatment exhibited a correspondingly greater stimulation. A common feature of taurine release in all the bove conditions was a slow response to the stimulus evoked by K+ and particularly to that evoked by veratridine. All ionotropic glutamate receptor agonists potentiated taurine release, but only the action of kainate seemed to be receptor-mediated. Metabotropic receptor agonists of group I slightly stimulated the release. The prolonged taurine release seen in both normoxia and cell-damaging conditions may be of importance in maintaining homeostasis in the cerebellum and reducing excitability for a longer period than other neuroprotective mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361658
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  • 24
    Electronic Resource
    Electronic Resource
    Evidence that taurine modulates osmoregulation by modification of osmolarity sensor protein ENVZ — expression (1999)
    Springer
    Amino acids 17 (1999), S. 347-355 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Taurine ; Osmoregulation ; Rat ; Osmolarity sensor protein ENVZ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Although the involvement of taurine in osmoregulation is well-documented and widely accepted, no detailed mechanism for this function has been reported so far. We used subtractive hybridization to study mRNA steady state levels of genes up- or downregulated by taurine. Rats were fed taurine 100mg/kg body weight per day for a period of three days and hearts (total ventricular tissue) of experimental animals and controls were pooled and used for mRNA extraction. mRNAs from two groups were used for subtractive hybridization. Clones of the subtractive library were sequenced and the obtained sequences were identified by gen bank assignment. Two clones were found to contain sequences which could be assigned to the osmolarity sensor protein envZ, showing homologies of 61 and 65%. EnvZ is an inner membrane protein in bacteria, important for osmosensing and required for porine gene regulation. It undergoes autophosphorylation and subsequently phosphorylates OmpR, which in turn binds to the porin (outer membrane protein) promoters to regulate the expression of OmpF and OmpC, major outer membrane porines. This is the first report of an osmosensing mechanism in the mammalian system, which was described in bacteria only. Furthermore, we are assigning a tentative role for taurine in the osmoregulatory process by modifying the expression of the osmoregulatory sensor protein ENVZ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361660
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  • 25
    Electronic Resource
    Electronic Resource
    Inhibitory effect of arginine-derivatives from ginseng extract and basic amino acids on protein-arginine N-methyltransferase (1999)
    Springer
    Amino acids 17 (1999), S. 391-400 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Protein ; arginine methyltransferase ; Inhibitors ; Ginseng extract ; Arginine derivatives ; Basic amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Protein-arginine N-methyltransferase (protein methylase I) catalyzes methylation of arginyl residues on substrate protein posttranslationally utilizing S-adenosyl-L-methionine as the methyl donor and yields NG-methylarginine residues. Arginyl-fructose and arginyl-fructosyl-glucose from Korean red ginseng were found to inhibit protein methylase I activity in vitro. This inhibitory activity was shown to be due to arginyl moiety in the molecules, rather than that of carbohydrates. Several basic amino acids as well as polyamines were also found to inhibit protein methylase I activity. Interestingly, the intensity of the inhibitory activity was correlated with the number of amino-group in polyamines, thus, in the order of spermine 〉 spermidine 〉 putrescine 〉 agmatine-sulfate, with IC50 at approximately 15 mM, 25 mM, 35 mM, and 50 mM, respectively. On the other hand, neutral amino acids or NaCI did not inhibit the enzyme activity. Lineweaver-Burk plot analysis of the protein methylase I activity in the presence of arginine and spermidine indicated that the inhibition was competitive in nature in respect to protein substrate, with the Ki values of 24.8 mM and 11.5 mM, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361664
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  • 26
    Electronic Resource
    Electronic Resource
    A new protection/activation strategy for the synthesis of naturally occurring and non-naturalα-N-alkylamino acids (1999)
    Springer
    Amino acids 16 (1999), S. 287-295 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Hexafluoroacetone ; α-N-Methylamino acids ; α-N-Phosphinoylmethylamino acids ; Pro-Glu-chimeras ; Pro-Tauchimeras
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A new method for the preparation of N-methylamino acids and some of their derivatives starting from hexafluoroacetone protected amino acids is described. The new concept results in saving of steps compared to conventional protection/activation techniques. Protection and deprotection proceed without racemization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01388173
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  • 27
    Electronic Resource
    Electronic Resource
    Synthesis of perfluoroalkylatedβ-alanine and some peptide derivatives: An access to original surfactants (1999)
    Springer
    Amino acids 16 (1999), S. 381-389 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Perfluorinated compounds ; Surfactants ; Complexing properties ; Carnosine ; β ; Amino acids ; Blood substitutes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The reaction of amines or sodium azide with 3-perfluoroalkyl-3-fluoroprop-2-enoate, followed by hydrogenation, affords perfluoroalkylatedβ-alanine analogues in very good yields. These compounds can be linked via an amide bond to produce peptide analogues such as carnosine or carcinine derivatives, which could have surfactive and complexing properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01388177
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  • 28
    Electronic Resource
    Electronic Resource
    Cu(III)-Polypeptide complexes exhibiting SOD-like activity (1999)
    Springer
    Amino acids 16 (1999), S. 415-423 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; SOD-like activity ; Cu (III)-Poly-L-lysine ; Cu(III)-Poly-L-glutamic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The SOD-like activity of Cu(III) -complexes with polypeptides poly-L-lysine and poly-L-glutamic acid respectively was investigated. The Cu(II)-polypeptide complexes were first oxidized by K2IrCl6 to give the corresponding Cu(III) -compounds. The oxidation of Cu(II) and the corresponding Cu(II)/Cu(III) potential was evaluated by cyclic voltammetry (c.v.), UV-Vis and EPR spectroscopic (r.t.) experiments. Spin trapping EPR spectra were also conducted to confirm the formation of the superoxide radical. The SOD-like activity of each Cu(III)-complex was proved using the nitro blue tetrazolium (NBT) method slightly modified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01388180
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  • 29
    Electronic Resource
    Electronic Resource
    Effect of some herbicides on the production of lysine byAzotobacter chroococcum (1999)
    Springer
    Amino acids 17 (1999), S. 165-173 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Lysine ; Herbicides ; Azotobacter ; Xenobiotics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Production of lysine byAzotobacter chroococcum strain H23 was studied in chemically-defined media amended with different concentrations of alachlor, metolachlor, 2,4-D, 2,4,5-T and 2,3,6-TBA. The presence of 5, 10, and 50μg/ml of alachlor or 2,3,6-TBA significantly decreased quantitative production of lysine. However, the presence 2,4-D or 2,4,5-T at concentrations of 10 and 50μg/ml enhanced the production of lysine. Quantitative production of lysine was not affected as consequence of the addition of metolachlor to the culture medium, showing that the release lysine to the culture media byA. chroococcum was not affected by that herbicide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361879
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  • 30
    Electronic Resource
    Electronic Resource
    Synthesis and enzymology of modifiedN-benzyloxycarbonyl-L-cysteinylglycyl-3,3-dimethylaminopropylamide disulphides as alternative substrates for trypanothione reductase fromTrypanosoma crud: Part 3 (1999)
    Springer
    Amino acids 17 (1999), S. 175-183 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Trypanothione ; Glutathione ; Benzyloxycarbonyl-reductase ; Hydrocinnamoyl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Kinetic data for alternative substrates of recombinant trypanothione reductase fromTrypanosoma cruzi were measured for a series ofN-substituted-L-cysteinylglycyl-3-dimethylaminopropylamides, in which the cysteineN-substituent was either a variant of the benzyloxycarbonyl group or was L-phenylalanine or L-tryptophan. Replacing the benzylic ether oxygen atom by CH2. or NH had relatively minor effects on kcat, but raised the value of Km, 4.5- and 10-fold, respectively. Similarly, relative to the carbobenzoxy group, anN-L-phenylalanyl orN-L-tryptophanyl replacement on the cysteine hardly altered kcat, but increased Km, values by 16.6 and 7.4 fold, respectively. These observations were consistent with the Km, values referring primarily to binding for this series of nonspecific substrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361880
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  • 31
    Electronic Resource
    Electronic Resource
    Ion permeation properties of a cloned human 5-HT3 receptor transiently expressed in HEK 293 cells (1999)
    Springer
    Amino acids 17 (1999), S. 243-255 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Serotonin receptor ; Serotonin-3 receptor ; Ion channel ; Ion permeability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human 5-HT3 receptors expressed in HEK 293 cells were studied using patch-clamp techniques. The permeability ratios of cations to Na+ were Li+, 1.16; K+, 1.04; Rb+, 1.11; Cs+ 1.11; NMDG+, 0.04; Ca2+, 0.49, and Mg2+, 0.37. The permeability sequence of the alkali metal cations was Li+ 〉 Rb+ = Cs+ 〉 K+ 〉 Na+. Increased external concentrations of Ca2+ or Mg2+ decreased 5-HT-induced currents at all potentials tested in a voltage-independent manner. The single-channel conductance of human 5-HT3 receptors measured by fluctuation analysis of whole-cell currents was 790 ± 100fS. Differences in the basic properties of 5-HT3 receptors between species may explain interspecies differences in pharmacological properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01366923
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  • 32
    Electronic Resource
    Electronic Resource
    Taurine modulates expression of transporters in rat brain and heart (1999)
    Springer
    Amino acids 17 (1999), S. 301-313 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Taurine ; Transporter ; Rat ; Brain ; Heart
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In pro- and eucaryotic life, cellular and subcellular compartments are separated by membranes and the regulated and selective passage of specific molecules across these membranes is a basic and highly conserved principle. We were interested whether taurine, a naturally occuring amino acid, would be able to induce or suppress expression of transporters with the Rationale that taurine was shown to detoxify a series of endogenous toxins and xenobiotics of various chemically non-related structures. For this purpose we used a gene hunting technique, subtractive hybridization, subtracting mRNAs of taurine-treated rat brain and heart from untreated controls. Subtracted mRNAs were then converted to cDNAs, amplified, sequenced and identified by gene bank data. We found five transporter transcripts, the phosphonate transport ATPase PHNC, multidrug transporter homolog MTH104, protein-exportmembrane protein SECD, oligopeptide transporters oppA and oppD, in the brain and two: ABC-transporter BRAF-2 and cation-transport ATPase PACS, in the heart. Homologies of the sequences found were in any case 〉50% thus permitting the identification of transporters with high probability. The biological meaning could be that a naturally occuring amino acid, taurine, modulates complex transport systems. The most prominent finding is the upregulation of a multidrug transporter transcript, explaining a mechanism for the nonselective detoxifying action of taurine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01366929
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  • 33
    Electronic Resource
    Electronic Resource
    Production of tyrosine and other aromatic compounds from phenylalanine by rumen microorganisms (1999)
    Springer
    Amino acids 17 (1999), S. 335-346 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Tyrosine ; Phenylalanine ; Aromatic compounds ; Rumen microorganisms[/klw]
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rumen contents from three fistulated Japanese native goats fed Lucerne hay cubes (Medicago sativa) and concentrate mixture were collected to prepare the suspensions of mixed rumen bacteria (B), mixed protozoa (P) and a combination of the two (BP). Microbial suspensions were anaerobically incubated at 39°C for 12h with or without 1 MM ofl-phenylalanine (Phe). Phe, tyrosine (Tyr) and other related compounds in both supernatant and microbial hydrolysates of the incubations were analyzed by HPLC. Tyr can be produced from Phe not only by rumen bacteria but also by rumen protozoa. The production of Tyr during 12h incubation in B (183.6 μmol/g MN) was 4.3 times higher than that in P. One of the intermediate products between Phe and Tyr seems to bep-hydroxyphenylacetic acid. The rate of the net degradation of Phe incubation in B (76.O μmol/g MN/h) was 2.4 times higher than in P. In the case of all rumen microorganisms, degraded Phe was mainly (〉53%) converted into phenylacetic acid. The production of benzoic acid was higher in P than in B suspensions. Small amount of phenylpyruvic acid was produced from Phe by both rumen bacteria and protozoa, but phenylpropionic acid and phenyllactic acid were produced only by rumen bacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361659
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  • 34
    Electronic Resource
    Electronic Resource
    Antimicrobial activity ofo-carboranylalanine (1999)
    Springer
    Amino acids 17 (1999), S. 357-368 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; o-Carboranylalanine ; Histidine ; Bacteria ; Fungi ; Oomycota ; Plasmopara
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Functionalized polyhedral carboranes, including amino acid analogs, have unique physicochemical properties and are used as experimental anticancer agents. However, our current knowledge on their effect in nonmammalian biological systems is limited. We investigated the activity spectrumin vitro ofo-carboranylalanine (o-Cba), considered to be a highly lipophilic analog of phenylalanine, against representative plant pathogenic bacteria and fungi of various taxonomic position. The antibacterial effect ofo-Cba against some species was comparable to that of the widely used agricultural antibiotic, streptomycin. The sensitivity of individual bacterial species too-Cba within the same genus varied to a greater extent than the average sensitivity of various genera. In general, this carborane-containing amino acid was more toxic to Gram positive bacteria (Bacillus, Corynebacterium, Curtobacterium, Micrococcus, Rhodococcus, and Staphylococcus) than to Gram negative ones (Agrobacterium, Erwinia, Escherichia, Pseudomonas, Rhizobium, and Xanthomonas). Compared to the commercial fungicide, prochloraz,o-Cba was weakly toxic against various fungi (Zygo- and Ascomycota). It was also inferior to the commercial fungicide metalaxyl in inhibiting the vegetative growth of oomyceteous plant pathogens (Pythium irregulare, Phytophthora cryptogea and Plasmopara halstedii). Against the asexual spores of P. halstedii,o-Cba, however, was over a thousandfold more active than tridemorph, a selective zoospore inhibitor fungicide. For all taxonomic groups, the observed antimicrobial effect ofo-Cba could be diminished with histidine, but not with phenylalanine. In studies on healthy and mildew-infected sunflower and tobacco plantso-Cba showed neither fungicidal nor phytotoxic effects at 500ppm. This is the first report on the biological activity spectrum of a carborane-containing amino acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361661
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  • 35
    Electronic Resource
    Electronic Resource
    Where does indolylacrylic acid come from (1999)
    Springer
    Amino acids 17 (1999), S. 401-413 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Indolylacrylic acid ; Tryptophan ; Indolylacryloylglycine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In addition to the main catabolic routes of tryptophan (Trp), there exist minor and less thoroughly investigated pathways; one of these leads to indolylacrylic acid (IAcrA). IAcrA is a plant growth hormone, whereas its biological role in animals is still obscure, as is the way and site where it is formed in the organism. A two-stage production is likely: Intestinal microorganisms catabolize Trp to indole derivatives which are then absorbed and converted to IAcrA and its glycine conjugate, indolylacryloylglyeine (IAcrGly). Our finding of IAcrGly in the urine of proven germ-free piglets points to the possibility that Trp can be converted to IAcrA without the intervention of intestinal microorganisms. Seasonal and age variations, influence of light and connection with photodermatoses have been reported. Besides other pathological conditions the differences in IAcrGly excretion relative to normal controls were especially pronounced in some myopathies, namely in boys with Duchenne muscular dystrophy.
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    URL: http://dx.doi.org/10.1007/BF01361665
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  • 36
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    Electronic Resource
    Variation in competitive abilities of plants and microbes for specific amino acids (1999)
    Springer
    Biology and fertility of soils 29 (1999), S. 257-261 
    Details
    ISSN: 1432-0789
    Keywords: Key words Alpine nitrogen cycle ; Amino acids ; Kobresia myosuroides ; Organic nitrogen ; Plant-microbe competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Microbes are assumed to possess strong competitive advantages over plants for uptake of nutrients from the soil. The finding that non-mycorrhizal plants can obtain a significant fraction of their N requirement from soil amino acids contradicts this assumption. The amino acid glycine (Gly) has been used as a model amino acid in many recent studies. Our preliminary studies showed that Gly was a poor substrate for microbial growth compared to other amino acids. We tested the hypothesis that the alpine sedge Kobresia myosuroides competes better for Gly than for other amino acids because of decreased microbial demand for this compound. Soil microbial populations that could grow using Gly as a sole carbon source were about 5 times lower than those that could grow on glutamate (Glu). Gly supported a significantly lower population than any of the ten other amino acids tested except serine. In contrast, K. myosuroides took up Gly from hydroponic solution at faster rates than Glu. In plant-soil microcosms, plants competed with soil microbes 3.25 times better for Gly than for Glu. We conclude that the low microbial demand and the rapid plant uptake of Gly relative to other amino acids allow Gly to be an especially important nitrogen source for K. myosuroides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050550
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  • 37
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    Electronic Resource
    Isolation of RNA and Protein from Guard Cells of Nicotiana glauca (1999)
    Springer
    Plant molecular biology reporter 17 (1999), S. 371-383 
    Details
    ISSN: 1572-9818
    Keywords: epidermal peel ; extraction ; gene expression ; stomata ; tree tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stomatal guard cells are critical for maintenance of plant homeostasis and represent an interesting cell type for studies of leaf cell differentiation and patterning. Here we describe techniques for the isolation of guard cell RNA and protein from blended epidermal peels of Nicotiana glauca. The RNA isolation procedure is a modification of the hot borate method, which is particularly well-suited for recalcitrant tissues. Protein was extracted by disrupting guard cell-enriched epidermis with a French® press. This system offers the following advantages: relatively high yield, low or no contamination by other cell types, fresh tissue as a source of RNA and protein rather than protoplasts, and a plant species that is readily transformable. These techniques will allow for cloning and analysis of genes expressed in guard cells, application of traditional biochemical techniques to guard cell proteins, as well as characterization of genetic manipulation of guard cell function in transgenic plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007602017492
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  • 38
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    Electronic Resource
    PPARγ, the ultimate thrifty gene (1999)
    Springer
    Diabetologia 42 (1999), S. 1033-1049 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Adipogenesis ; adipose tissue ; cofactors ; gene expression ; fatty acids ; insulin resistance ; nuclear receptors ; prostaglandin ; thiazolidinediones ; Type II diabetes ; transcription.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The peroxisome proliferator-activated receptor gamma (PPARγ) quickly evolved over the last decade from a new orphan receptor to one of the best characterized nuclear receptors. This fast pace in PPARγ research was triggered by two main discoveries. Firstly, that PPARγ was shown to have a key role in adipogenesis and be a master controller of the “thrifty gene response” leading to efficient energy storage. Secondly, the discovery that its synthetic ligands, the thiazolidinediones, are promising insulin sensitizing drugs, which are currently being developed for the treatment of Type II (non-insulin-dependent) diabetes mellitus. More recently this nuclear receptor emerged from a role limited to metabolism (diabetes and obesity) to a power player in general transcriptional control of numerous cellular processes, with implications in cell cycle control, carcinogenesis, inflammation, atherosclerosis and immunomodulation. This widened role of PPARγ will certainly initiate a new flurry of research, which will not only refine our current often partial knowledge of PPARγ but more importantly also establish that this receptor has a definite role as a primary link adapting cellular, tissue and whole body homeostasis to energy stores. [Diabetologia (1999) 42: 1033–1049]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051268
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  • 39
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    Electronic Resource
    Development of chemical and sensory characteristics during enzymatic hydrolysis of soy (1999)
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 208 (1999), S. 50-56 
    Details
    ISSN: 1431-4630
    Keywords: Key words Flavor enhancer ; Savory flavoring ; Taste ; Amino acids ; Partial least squares regression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Enzymatically hydrolyzed vegetable protein was produced from soy protein using hydrolysis times of 0–20 h. The development of sensory properties and the pattern of protein degradation was followed. Around two-thirds of the final amount of free amino acids and degree of hydrolysis (DH) were achieved during the first 4 h of hydrolysis. Between 6 h and 10 h of hydrolysis the bouillon-like tastes increased significantly (P〈0.001). In this time interval the amount of free amino acids exceeded 40% of the total amino acids and the DH exceeded 50% of the theoretically possible (100%). Using partial least squares regression with standardisation of free amino acid data according to their taste threshold values showed that free glutamic acid, aspartic acid and lysine correlated with the bouillon-like tastes. By standardisation of free amino acid data with respect to their SD the specificity of the enzymes for amino acid side-chains could be seen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002170050374
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  • 40
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    Electronic Resource
    Uncoupling protein-3 gene expression: reduced skeletal muscle mRNA in obese humans during pronounced weight loss (1999)
    Springer
    Diabetologia 42 (1999), S. 302-309 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Obesity ; genetics ; uncoupling protein-3 ; gene expression ; skeletal muscle.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims: Uncoupling protein-3 is a member of a protein family that serves to dissipate energy in the form of heat thereby modulating energy expenditure. Alternative processing of uncoupling protein-3 transcripts results in two mRNA species that encode a large and small protein, perhaps differing in functional activity. Since obesity is associated with disrupted energy homeostasis, we measured muscle mRNA expression in morbidly obese and lean subjects. Methods: The two uncoupling protein-3 mRNA species were quantified in muscle tissue using an RNase protection assay. Gene locus effects on mRNA expression were studied by quantitative allele-specific primer extension. Results: In both obese and lean subjects, the mRNA species encoding the small protein isoform was twice as abundant as the mRNA species encoding the large protein isoform. Neither the total uncoupling protein-3 mRNA expression nor the molar abundance ratios of the two mRNA species differed between obese and lean male or female subjects. Women who had lost 37 ± 22 kg of weight in response to dietary restriction and continued a hypocaloric diet displayed lower mRNA than obese (p 〈 0.005) or lean women (p 〈 0.05). Primer extension assays in lean and obese subjects showed similar allelic mRNA abundance in all but one subject studied. Conclusion: Muscle expression of the two uncoupling protein-3 mRNA species is similar in obese and lean people. In obese patients, prolonged hypocaloric diet downregulates uncoupling protein-3 mRNA expression in muscle and can thereby enhance its energy efficiency. Sequence substitutions at the gene locus may only be minor determinants of mRNA expression in muscle tissue. [Diabetologia (1999) 42: 302–309]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051155
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  • 41
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    Electronic Resource
    Regulation of UCP2 and UCP3 by muscle disuse and physical activity in tetraplegic subjects (1999)
    Springer
    Diabetologia 42 (1999), S. 826-830 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Uncoupling proteins ; exercise ; tetraplegia ; skeletal muscle ; mRNA ; gene expression ; polymerase chain reaction.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. The regulation of uncoupling protein 2 and uncoupling protein 3 gene expression in skeletal muscle has recently been the focus of intense interest. Our aim was to determine expression of uncoupling protein 2 and 3 in skeletal muscle from tetraplegic subjects, a condition representing profound muscle inactivity. Thereafter we determined whether exercise training would modify expression of these genes in skeletal muscle. Methods. mRNA expression of uncoupling protein 2 and 3 was determined using quantitative reverse transcription-polymerase chain-reaction. Results. Expression of uncoupling protein 2 and 3 mRNA was increased in skeletal muscle from tetraplegic compared with able-bodied subjects (3.7-fold p 〈 0.01 and 4.1-fold, p 〈 0.05, respectively). A subgroup of four tetraplegic subjects underwent an 8-week exercise programme consisting of electrically-stimulated leg cycling (ESLC, 7 ESLC sessions/week). This training protocol leads to increases in whole body insulin-stimulated glucose uptake and expression of genes involved in glucose metabolism in skeletal muscle from tetraplegic subjects. After ESLC training, uncoupling protein 2 expression was reduced by 62 % and was similar to that in able-bodied people. Similarly, ESLC training was associated with a reduction of uncoupling protein 3 expression in skeletal muscle from three of four tetraplegic subjects, however, post-exercise levels remained increased compared with able-bodied subjects. Conclusion/interpretation. Tetraplegia is associated with increased mRNA expression of uncoupling protein 2 and 3 in skeletal muscle. Exercise training leads to normalisation of uncoupling protein 2 expression in tetraplegic subjects. Muscle disuse and physical activity appear to be powerful regulators of uncoupling protein 2 and 3 expression in human skeletal muscle. [Diabetologia (1999) 42: 826–830]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051233
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  • 42
    Electronic Resource
    Electronic Resource
    The influence of maturation on flavor and chemical composition of hydrolyzed soy protein produced by acidic and enzymatic hydrolysis (1999)
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 208 (1999), S. 355-361 
    Details
    ISSN: 1431-4630
    Keywords: Key words Flavor enhancer ; Taste ; Amino acids ; Carbohydrates ; Maillard reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Hydrolyzed vegetable protein produced using hydrochloric acid (HVP) or proteolytic enzymes (EVP) was given a maturation period of up to 6 weeks at 30  °C. The maturation resulted in a darker color for both hydrolysates, but the sensory profiles were not altered to any great extent. For both hydrolysates a decrease in the amount of free amino acids or an increase in the amount of bound amino acids was seen, and for EVP, a decrease in the amount of free monosaccharides was likewise observed. In HVP the mono- and polysaccharides were destroyed during hydrolysis. The changes in amino acids could be due to, for example, a reversible binding to either a monosaccharide in EVP or a degradation product of carbohydrates in HVP, leading to the first stage of the Maillard reaction. These early reactions did not proceed to any flavor-giving Maillard reaction compounds. Maturation can therefore not be used to enhance the flavor of protein hydrolysates under the applied production conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002170050429
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  • 43
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    Electronic Resource
    Effects of GABA-transaminase inhibition on brain metabolism and amino-acid compartmentation: an in vivo study by 2D 1H-NMR spectroscopy coupled with microdialysis (1999)
    Springer
    Experimental brain research 127 (1999), S. 321-327 
    Details
    ISSN: 1432-1106
    Keywords: Key words Gabaculine ; NMR spectroscopy ; Microdialysis ; Amino acids ; Compartmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The aim of this work was to study the neurochemical effects in the brain of GABA-transaminase inhibition by systemic administration of gabaculine (100 mg/kg, i.a.) in the rat. In order to investigate neurotransmitter and related amino-acid compartmentation and metabolism, we have developed an original tool: the coupling, in vivo, on the same animal, of 2D COSY 1H-NMR spectroscopy with intracerebral microdialysis. The main result is a continuous increase in GABA levels, both in the intracellular compartment (up to 3000±450%; P〈0.001) and extracellular compartment (up to 808±82%; P〈0.01) at the sixth hour. The intracellular increase in GABA level became significant at the first hour following gabaculine administration, whereas the extracellular level increased as of the second hour, probably indicating that accumulation of GABA in nerve endings precedes its release in synaptic clefts. Moreover, the levels of the excitatory amino acids, glutamate and aspartate, were decreased both in the intra- and extracellular compartments, thus enhancing sedative effects of the drug. We also observed a decrease in the global energetic creatine-phosphocreatine pool, which also could be related to the sedative properties of gabaculine, measurable by the diminution of cortical electrical activity and mean arterial blood pressure. Finally, the coupling between 2D 1H-NMR spectroscopy and intracerebral microdialysis appears to be an original tool for investigating the cerebral metabolic effects induced by pharmacological agents, in situ, in living animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050802
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  • 44
    Electronic Resource
    Electronic Resource
    A food web analysis of the juvenile blue crab, Callinectes sapidus, using stable isotopes in whole animals and individual amino acids (1999)
    Springer
    Oecologia 120 (1999), S. 416-426 
    Details
    ISSN: 1432-1939
    Keywords: Key words Estuarine food web ; Stable isotopes ; Amino acids ; Growth experiment ; Crustacean metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The stable isotope compositions (C and N) of plants and animals of a marsh dominated by Spartina alterniflora in the Delaware Estuary were determined. The study focused on the juvenile stage of the Atlantic blue crab, Callinectes sapidus, and the importance of marsh-derived diets in supporting growth during this stage. Laboratory growth experiments and field data indicated that early juvenile blue crabs living in the Delaware Bay habitat fed primarily on zooplankton, while marsh-dwelling crabs, which were enriched in 13C relative to bay juveniles, utilized marsh-derived carbon for growth. In laboratory experiments, the degree to which juvenile blue crabs isotopically fractionated dietary nitrogen, as well as the growth rate, depended on the protein quality of the diet. The range of δ13C of amino acids in laboratory-reared crabs and their diets was almost 20‰, similar to the isotopic range of amino acids of other organisms. In laboratory studies, the δ13C of nonessential and essential amino acids in the diet were compared to those in juvenile crabs. Isotopic fractionation at the molecular level depended on diet quality and the crabs' physiological requirements. Comparison of whole-animal isotope data with individual amino acid C isotope measurements of wild juvenile blue crabs from the bay and marsh suggested a different source of total dietary carbon, yet a shared protein component, such as zooplankton.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050874
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  • 45
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    Electronic Resource
    Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on liver phosphoenolpyruvate carboxykinase (PEPCK) activity, glucose homeostasis and plasma amino acid concentrations in the most TCDD-susceptible and the most TCDD-resistant rat strains (1999)
    Springer
    Archives of toxicology 73 (1999), S. 323-336 
    Details
    ISSN: 1432-0738
    Keywords: Key words 2 ; 3 ; 7 ; 8-Tetrachlorodibenzo-p-dioxin ; TCDD ; Phosphoenolpyruvate carboxykinase ; PEPCK ; Glucose ; Glycogen ; Amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Reduced gluconeogenesis due to decreased activity of key gluconeogenic enzymes in liver, together with feed refusal, has been suggested to play an important role in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced lethality in rats. This study was carried out to further analyse the toxicological significance of reduced gluconeogenesis by comparing dose-responses and time-courses of effects of TCDD on the activity of phosphoenolpyruvate carboxykinase (PEPCK) in liver, liver glycogen concentration as well as plasma concentrations of glucose and amino acids in both genders of TCDD-sensitive Long-Evans (L-E) rats and TCDD-resistant Han/Wistar (H/W) rats. A dose-dependent decrease in PEPCK activity was observed in H/W rats, but in L-E rats the activity was not decreased. However, TCDD impaired the strong increase in liver PEPCK activity observed in pair-fed controls of the L-E strain. Liver glycogen concentrations were severely decreased in L-E rats and moderately in H/W rats. This effect seems to be secondary to reduced feed intake, since a similar decrease was seen in pair-fed controls. Decreases in plasma glucose concentrations were also more profound in L-E rats than in H/W rats, but pair-fed controls were generally less affected. Circulating concentrations of amino acids were markedly increased in TCDD-treated L-E rats, which is likely to reflect increased mobilization of amino acids and their decreased metabolism in liver. Reduction of liver PEPCK activity cannot account for the sensitivity difference of these two strains of rats in terms of mortality. Nevertheless, the response of both strains of TCDD-treated rats regarding gluconeogenesis is different from that seen in pair-fed controls and suggesting that impairment of this pathway contributes to the development of the wasting syndrome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002040050626
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  • 46
    Electronic Resource
    Electronic Resource
    Terfenadine induces toxicity in cultured cerebellar neurons: A role for glutamate receptors (1999)
    Springer
    Amino acids 16 (1999), S. 59-70 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Cerebellar granule cells ; Neurotoxicity ; Terfenadine ; Excitatory amino acids ; Histamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Exposure of cultured cerebellar neurons to the histamine H1 receptor antagonist terfenadine resulted in neuronal degeneration and death. Terfenadine neurotoxicity was dependent upon concentration and time of exposure. After 2h exposure, 20µM terfenadine reduced the number of surviving neurons by 75%, and as low as 10nM terfenadine induced significant neurotoxicity after 5 days of exposure. Neuronal sensitivity to terfenadine changed with age in culture, and at 25 days in culture neurons appeared to be much less sensitive than at 5 or 9–17 days in culture. Neurotoxicity by terfenadine could not be prevented by high concentrations of histamine (5 mM), but it was significantly delayed by blocking NMDA or non-NMDA glutamate receptors with MK-801 or CNQX respectively, suggesting the involvement of excitatory transmission mediated by glutamate in the neurotoxicity induced by terfenadine in these neurons. We also found that the presence of terfenadine (5,µM) unveiled the potential excitotoxicity of the non-NMDA receptor agonist AMPA (100µM), and reduced the concentration of glutamate necessary to induce excitotoxicity, compared to untreated cultures. These results suggest a role for terfenadine in the modulation of the excitotoxic response mediated in cerebellar neurons through ionotropic glutamate receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01318885
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  • 47
    Electronic Resource
    Electronic Resource
    Structural organization of the human eukaryotic initiation factor 5A precursor and its site-directed variant Lys50 → Arg (1999)
    Springer
    Amino acids 16 (1999), S. 91-106 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; eIF-5A ; Hypusine ; Protein folding ; Posttranslational modification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The molecular properties of the human eukaryotic initiation factor 5A precursor and its site directed Lys50 → Arg variant have been investigated and compared. Structure perturbation methods were used to gain information about the protein architecture in solution. Intrinsic and extrinsic spectroscopic probes strategically located in the protein matrix detected the independent unfolding of two molecular regions. Three cystemes out of four were titrated in the native protein and the peculiar presence of a tyrosinate band at neutral pH was detected. At alkaline pH only two tyrosines out of three were titratable in the native protein, with an apparent pK of about 9.9. Native protein and its Lys50 → Arg variant reacted in a similar fashion to guanidine and to pH variation, but differently to thermal stress. The complex thermal unfolding of both proteins indicated the presence of intermediates. Spectroscopic data showed that these intermediates are differently structured. Consequently, the two proteins seem to have different unfolding pathways.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01318888
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  • 48
    Electronic Resource
    Electronic Resource
    Renal handling of amino acids in 5/6-nephrectomized rats: Stimulation of renal amino acid reabsorption after treatment with triiodothyronine or dexamethasone under amino acid load (1999)
    Springer
    Amino acids 16 (1999), S. 149-164 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; 5/6 nephrectomy ; Renal failure ; Amino acid transport ; Kidney ; Triiodothyronine ; Dexamethasone ; Amino acid load ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In anaesthetized adult female rats, the renal amino acid handling was measured six days after 5/6 nephrectomy (5/6NX). The distinct rise in blood urea nitrogen as well as the significant reduction in urine flow and GFR indicate an impairment of kidney function. In principle, in 5/6NX rats amino acid plasma concentrations were comparable to those of control animals with two intact kidneys, whereas the fractional excretions (FEAA) of most endogenous amino acids measured were significantly enhanced. After bolus injection of leucine or taurine (each 20 mg/100 g b.wt.) or glutamine (90 mg/ 100 g b.wt.), dissolved in 2m1 normal saline per 100 g b.wt., the FEAA of both the amino acids administered and the endogenous amino acids increased as a sign of overloaded amino acid reabsorption capacity. This effect was more pronounced in 5/6NX rats than in controls. As early as one hour after amino acid load, plasma concentrations and FEAA returned to baseline values of 5/6NX rats. A pretreatment with triiodothyronine (20,µg/100 g b.wt.) or dexamethasone (60 µg/100 g b.wt.), both given intraperitoneally once daily for 3 days, stimulated the renal amino acid transport capacity in 5/6NX rats: the increase in FEAA after amino acid load was significantly lower compared to non-pretreatred animals. This stimulation could be shown for the bolus amino acids and the endogenous amino acids and was more distinct in 5/6NX rats than in controls with two intact kidneys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01321533
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  • 49
    Electronic Resource
    Electronic Resource
    Nitric oxide mediates either proliferation or cell death in cardiomyocytes. Involvement of polyamines (1999)
    Springer
    Amino acids 16 (1999), S. 181-190 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Nitric oxide ; Ornithine decarboxylase ; Proliferation ; Cell death ; Cardiomyocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nitric oxide (NO) is a molecule involved in several signal transduction pathways leading either to proliferation or to cell death. Induction of ornithine decarboxylase (ODC), the key enzyme of polyamine biosynthesis, represents an early event preceding DNA synthesis. In some cell types increased ODC activity seems to be involved in cytotoxic response. We investigated the role of NO and ODC induction on the events linked to cell proliferation or to cell death in cultured chick embryo cardiomyocytes. Exposure of cardiomyocytes to tumor necrosis factor (TNF) and lipopolysaccharide (LPS) caused NO synthase (NOS) and ODC induction as well as increased incorporation of [3H]-thymidine. This last effect was blocked by a NOS inhibitor and was strongly reduced by difluoromethylornithine (DFMO), an irreversible inhibitor of ODC. Sodium nitroprusside (SNP), an exogenous NO donor, inhibited the increases of NOS and ODC activities and abolished the mitogenic effect of TNF and LPS. Moreover, SNP alone caused cell death in a dose dependent manner. The cytotoxicity of SNP was not affected by DFMO while it was prevented by antioxidants. The results suggest that different pathways would mediate the response of cardiomyocytes to NO: they can lead either to ODC induction and DNA synthesis when NO is formed through NOS induction or to growth inhibition and cell death, when NO is supplied as NO donor. Increased polyamine biosynthesis would mediate the proliferative response of NO, while the cytotoxicity of exogenous NO seems to involve some oxidative reactions and to depend on the balance between NO availability and cellular redox mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01321535
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  • 50
    Electronic Resource
    Electronic Resource
    Asymmetric syntheses of pipecolic acid and derivatives (1999)
    Springer
    Amino acids 16 (1999), S. 297-320 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Pipecolic acid ; Pipecolic acid derivatives ; Asymmetric synthesis ; Hemisyntheses ; Chiral auxiliaries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Results in the field of asymmetric synthesis of pipecolic acid derivatives are reviewed. Three sections describe the asymmetric syntheses of the title compounds (i) from the chiral pool (α-amino acids or carbohydrates) (ii) using a chiral auxiliary either derived from terpenes,α-amino acids, tartaric acid, an amine orβ-amino alcohols (iii) by means of asymmetric catalysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01388174
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  • 51
    Electronic Resource
    Electronic Resource
    Fromβ-lactams toα- andβ-amino acid derived peptides (1999)
    Springer
    Amino acids 16 (1999), S. 321-343 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Amino alcohols ; β-Lactams ; NCA ; Peptides ; Synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The potential ofβ-lactams as intermediates for the access toα- andβ-amino acid-derived peptides is shortly reviewed, with major focus on the technologies developed in our group. The two general strategies lie, on one side, in the oxidative ring expansion of 3-hydroxyβ-lactams toN-carboxyα-amino acid anhydrides or Leuch's anhydrides and subsequent coupling withα-amino acid esters and, on the other side, in the nucleophilic ring opening ofN-Boc-β-lactams. Both approaches have been successfully applied to the synthesis ofα,β-diamino acid,α-amino-β-hydroxy acid, polyhydroxylatedα-amino acid,α,α-disubstitutedα-amino acid,β-amino acid,β-amino-α-hydroxy acid andβ,β-disubstitutedβ-amino acid derived peptides. Because of the mild reaction conditions needed for the above transformations and the highly stereoselective procedures employed for the construction of the startingβ-lactam ring, the whole process allows the production of optically pure final products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01388175
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  • 52
    Electronic Resource
    Electronic Resource
    Clonidine action in spontaneously hypertensive rats (SHR) depends on the GABAergic system function (1999)
    Springer
    Amino acids 17 (1999), S. 131-138 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Clonidine ; GABAA receptor antagonists ; GABA turnover ; SHR ; WKY rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of γ-aminobutyric acid (GABA)A antagonists (bicuculline, picrotoxin) on clonidine hypotension in spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats were examined. The GABA turnover changes after clonidine injection in both strains were also studied. Administration of clonidine alone induced the stronger decrease of systolic blood pressure (SBP) in SHR. Co-dosage of clonidine with these agents reduced its hypotensive effect in dose dependent manner and the effectiveness of both antagonists was higher in SHR. We find that clonidine stimulates GABA synthesis in the hypothalamus and the pons-medulla in both strains but the GABA turnover rate is significantly slower in SHR. Therefore, the differences in inhibitory action of GABAA receptor anatgonists between WKY and SHR rats may be explained by central GABAergic system dysfunction in the hypertension. Our results indicate that the down regulation of the GABAergic system observed in hypertension may be compensated by the action of clonidine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361876
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  • 53
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    Electronic Resource
    Utilization ofd-amino acids byFusobacterium nucleatum andFusobacterium varium (1999)
    Springer
    Amino acids 17 (1999), S. 185-193 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Anaerobic bacteria ; Catabolism ; HPLC ; Stereochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The utilization ofd- andl -amino acids with acidic, basic or polar side chains was demonstrated by HPLC. Two species of the anaerobeFusobacterium utilized D-lysine and the L isomers of glutamate, glutamine, histidine, lysine and serine. OnlyF. varium usedl-arginine,d-glutamate andd-serine as substrates, whereasF. nucleatum specifically utilizedd-histidine andd-glutamine.d-Glutamate accumulated in F. nucleatum cultures supplemented withd-glutamine, and ornithine was detected when eitherdl- orl-arginine was included inF. varium cultures. Based on literature precedents,d-glutamate andd-histidine are isomerized to their L isomers prior to degradation, but separate catabolic pathways are possible for each enantiomer of lysine and serine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01361881
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  • 54
    Electronic Resource
    Electronic Resource
    Glutamine and the immune system (1999)
    Springer
    Amino acids 17 (1999), S. 227-241 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Glutamine ; Lymphocyte ; Macrophage ; Mononuclear cell ; Cytokine ; Infection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Glutamine is utilised at a high rate by cells of the immune system in culture and is required to support optimal lymphocyte proliferation and production of cytokines by lymphocytes and macrophages. Macrophage-mediated phagocytosis is influenced by glutamine availability. Hydrolysable glutamine dipeptides can substitute for glutamine to support in vitro lymphocyte and macrophage functions. In man plasma and skeletal muscle glutamine levels are lowered by sepsis, injury, burns, surgery and endurance exercise and in the overtrained athlete. The lowered plasma glutamine concentrations are most likely the result of demand for glutaminne (by the liver, kidney, gut and immune system) exceeding the supply (from the diet and from muscle). It has been suggested that the lowered plasma glutamine concentration contributes, at least in part, to the immunosuppression which accompanies such situations. Animal studies have shown that inclusion of glutamine in the diet increases survival to a bacterial challenge. Glutamine or its precursors has been provided, usually by the parenteral route, to patients following surgery, radiation treatment or bone marrow transplantation or suffering from injury. In most cases the intention was not to stimulate the immune system but rather to maintain nitrogen balance, muscle mass and/or gut integrity. Nevertheless, the maintenance of plasma glutamine concentrations in such a group of patients very much at risk of immunosuppression has the added benefit of maintaining immune function. Indeed, the provision of glutamine to patients following bone marrow transplantation resulted in a lower level of infection and a shorter stay in hospital than for patients receiving glutamine-free parenteral nutrition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01366922
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  • 55
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    Electronic Resource
    Alteration in the D-amino acid content of the rat pineal gland under anesthesia (1999)
    Springer
    Amino acids 17 (1999), S. 277-283 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; D-Aspartic acid ; D-Leucine ; Pineal gland ; Sympathetic nervous system ; Anesthesia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a previous report (Hamase, K. et al., Biochim Biophys Acta 1134: 214–222 (1997)), we showed that the rat pineal gland contains D-leucine (D-Leu) as well as D-aspartic acid (D-Asp). In this communication we report alterations in the content of these D-amino acids during anesthesia. The D-Asp content was significantly increased from 2.8 to 5.0, 4.8 and 5.8 nmol/pineal gland by administration of ether, urethane and pentobarbital, respectively. In contrast, the D-Leu content was decreased by administration of urethane or pentobarbital. The D-Leu content decreased from 4.2 to 2.2 pmol/pineal gland 4 hours after administration of urethane, although the content remained unchanged until 1.5 hours after administration. The content of the L-enantiomers of these amino acids were not affected by anesthesia. The urethane-induced decrease in D-leucine content was almost completely suppressed by aβ-agonist, (-)-isoproterenol, whereas the agonist itself had no effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01366926
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  • 56
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    Electronic Resource
    Urine glycyl-L-proline increase and skin trophicity (1999)
    Springer
    Amino acids 17 (1999), S. 315-322 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Glycyl-L-proline ; Urine ; Trophicity ; Collagen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Glycyl-L-proline (gly-pro) is an end product of collagen metabolism that is further cleaved by prolidase (EC 3.4.13.9); the resulting proline molecules are recycled into collagen or other proteins. We postulated a relationship between defective gly-pro hydrolysis, increased collagen degradation and skin destruction. This relationship was tested using HPLC to measure the gly-pro in urine. 24 hour urine samples were collected from 27 old people (86 ± 6 years old), of whom 15 were suffering from skin pressure sores of the sacrum or calcaneus. The urine from patients with pressure sores contained significantly more gly-pro than the urine from the control. A cut-off at 7μmol/ mmol creatinine gave the test a positive predictive value of 70%. Collagen breakdown was also increased as indicated by the increase of hydroxyproline (hyp) in the urine. But this breakdown seemed to stop at the gly-pro step.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01366930
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    Electronic Resource
    Involvement of metabotropic glutamate receptors in taurine release in the adult and developing mouse hippocampus (1999)
    Springer
    Amino acids 16 (1999), S. 165-179 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Taurine release ; Metabotropic glutamate receptors ; Hippocampal slices ; Adult ; Developing mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The inhibitory amino acid taurine has been held to function as an osmoregulator and modulator of neural activity, being particularly important in the immature brain. lonotropic glutamate receptor agonists are known markedly to potentiate taurine release. The effects of different metabotropic glutamate receptor (mGluR) agonists and antagonists on the basal and K+-stimulated release of [3H]taurine from hippocampal slices from 3-month-old (adult) and 7-day-old mice were now investigated using a superfusion system. Of group I metabotropic glutamate receptor agonists, quisqualate potentiated basal taurine release in both age groups, more markedly in the immature hippocampus. This action was not antagonized by the specific antagonists of group I but by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and 6-nitro-7-sulphamoylbenzo[f]quinoxaline-2,3-dione (NBQX), which would suggest an involvement of ionotropic glutamate receptors. (S)-3,5-dihydroxyphenylglycine (DHPG) potentiated the basal release by a receptor-mediated mechanism in the immature hippocampus. The group II agonist (2S, 2′R, 3′R)-2-(2′,3′-dicarboxycyclopropyl)glycine (DCG IV) markedly potentiated basal taurine release at both ages. These effects were antagonized by dizocilpine, indicating again the participation of ionotropic receptors. Group III agonists slightly potentiated basal taurine release, as did several antagonists of the three metabotropic receptor groups. Potassium-stimulated (50 mM K+) taurine release was generally significantly reduced by mGluR agents, mainly by group I and II compounds. This may be harmful to neurons in hyperexcitatory states. On the other hand, the potentiation by mGluRs of basal taurine release, particularly in the immature hippocampus, together with the earlier demonstrated pronounced enhancement by activation of ionotropic glutamate receptors, may protect neurons against excitotoxicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01321534
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  • 58
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    Electronic Resource
    Novel Technology for Detection of Genomic and Transcriptional Alterations in Pancreatic Cancer (1999)
    Springer
    Annals of oncology 10 (1999), S. 64-68 
    Details
    ISSN: 1569-8041
    Keywords: chromosomal aberrations ; gene expression ; oncogenes ; pancreatic cancer ; tumor suppressor genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aim: The present review summarizes our strategies aimed at identifying and characterizing genetic alterations occuring at the transcriptional and chromosomal level in pancreatic cancer. Methods: To study transcriptional alterations we have used a number of techniques including modified versions of differential hybridizations and cDNA-RDA (representational difference analysis). Comparative genomic hybridization (CGH) was used to study chromosomal aberrations occuring in pancreatic cancer tissues. Results: The study of transcriptional alterations led to the identification of more than 500 genes with differential expression in pancreatic cancer. The sum of these alterations represented the first expression profile characteristic for pancreatic tumors. The CGH analysis allowed the identification of a number of chromosomal regions containing putative tumor suppressor genes or oncogenes. These regions are presently being characterized at the molecular level. In a first approach the myb-oncogene was identified as the relevant oncogene of an amplification on 6q occurring in up to 10% of pancreatic cancer patients. Conclusions: Genes isolated in both approaches represent potential new disease genes for pancreatic cancer and are at present being characterized by individual or serial analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008392904359
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  • 59
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    Electronic Resource
    Increased peroxisomal fatty acid β-oxidation and enhanced expression of peroxisome proliferator-activated receptor-α in diabetic rat liver (1999)
    Springer
    Molecular and cellular biochemistry 194 (1999), S. 227-234 
    Details
    ISSN: 1573-4919
    Keywords: microbodies ; diabetes mellitus ; steroid hormone receptor ; β-oxidation ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract To determine whether the increased fatty acid β-oxidation in the peroxisomes of diabetic rat liver is mediated by a common peroxisome proliferation mechanism, we measured the activation of long-chain (LC) and very long chain (VLC) fatty acids catalyzed by palmitoyl CoA ligase (PAL) and lignoceryl CoA ligase and oxidation of LC (palmitic acid) and VLC (lignoceric acid) fatty acids by isotopic methods. Immunoblot analysis of acyl-CoA oxidase (ACO), and Northern blot analysis of peroxisome proliferator-activated receptor (PPAR-α), ACO, and PAL were also performed. The PAL activity increased in peroxisomes and mitochondria from the liver of diabetic rats by 2.6-fold and 2.1-fold, respectively. The lignoceroyl-CoA ligase activity increased by 2.6-fold in diabetic peroxisomes. Palmitic acid oxidation increased in the diabetic peroxisomes and mitochondria by 2.5-fold and 2.7-fold, respectively, while lignoceric acid oxidation increased by 2.0-fold in the peroxisomes. Immunoreactive ACO protein increased by 2-fold in the diabetic group. The mRNA levels for PPAR-α, ACO and PAL increased 2.9-, 2.8- and 1.6-fold, respectively, in the diabetic group. These results suggest that the increased supply of fatty acids to liver in diabetic state stimulates the expression of PPAR-α and its target genes responsible for the metabolism of fatty acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006930513476
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  • 60
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    Electronic Resource
    Expression of calcium-binding protein regucalcin mRNA in the cloned rat hepatoma cells (Hr-II-E) is stimulated through Ca2+ signaling factors: Involvement of protein kinase C (1999)
    Springer
    Molecular and cellular biochemistry 198 (1999), S. 101-107 
    Details
    ISSN: 1573-4919
    Keywords: regucalcin ; Ca2+-binding protein ; protein kinase C ; Ca2+signaling ; gene expression ; H4-II-E hepatoma cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The expression of hepatic Ca2+-binding protein regucalcin in the cloned rat hepatoma cells (H4-II-E) was investigated. The change in regucalcin mRNA levels was analyzed by Northern blotting using rat liver regucalcin complementary DNA (0.9 kb of open reading frame). Regucalcin mRNA was expressed in H4-II-E hepatoma cells. This expression was clearly stimulated in the presence of serum (10% fetal bovine serum). Bay K 8644 (2. 5 × 10-6 M), a Ca2+ channel agonist, significantly stimulated regucalcin mRNA expression in the absence or presence of 10% serum. Dibutyryl cyclic AMP (10-3 M) did not have a stimulatory effect on the regucalcin mRNA expression. The presence of phorbol 12-myristate 13-acetate (PMA; 10-6 M) or estrogen (10-8 M) caused a significant increase in regucalcin mRNA levels in the hepatoma cells cultured in serum-free medium, while insulin (5 × 10-9 M) or dexamethasone (10-6 M) had no effect. Bay K 8644-stimulated regucalcin mRNA expression in the hepatoma cells was completely blocked in the presence of trifluoperazine (10-5 M), an antagonist of calmodulin, or staurosporine (10-7 M), an inhibitor of protein kinase C. The stimulatory effect of PMA was clearly inhibited in the presence of stauroporine. The present study demonstrates that regucalcin mRNA is expressed in the transformed H4-II-E hepatoma cells, and that the expression is stimulated through Ca2+-dependent signaling factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006996506238
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  • 61
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    Posttranscriptional regulation of urokinase receptor gene expression in human lung carcinoma and mesothelioma cells in vitro (1999)
    Springer
    Molecular and cellular biochemistry 199 (1999), S. 189-200 
    Details
    ISSN: 1573-4919
    Keywords: lung ; cancer ; urokinase ; receptor ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The urokinase-type plasminogen activator (uPA) interacts with its receptor (uPAR) to promote proteolysis as well as cell proliferation and migration. These functions contribute to the pathogenesis of neoplastic growth and invasiveness. Expression of uPAR in tumor extracts also inversely correlates with prognosis in many forms of cancer. In this study, we sought to determine if differences in uPAR expression were distinguishable between cultured human lung carcinoma and malignant mesothelioma subtypes. We also sought to determine if, as in malignant mesothelioma cells, uPAR expression is regulated at the posttranscriptional level in cultured malignant lung carcinoma cells. Using 125I-uPA binding and ligand blotting techniques, uPAR was expressed by phenotypically diverse lung carcinoma cell lines, including the H460, H157 and H1395 non-small cell lines and the H146 small cell lung carcinoma line. Increased uPAR expression was also detected in spindle-shaped (M33K) and epithelioid (M9K and MS-1) malignant mesothelioma cells. Selected mediators, including TGF-β, TNF-α, LPS and PMA, uniformly enhanced uPAR expression in each of the tumor cell lines. Steady state uPAR mRNA expression was determined by RNase protection assay and correlated directly with the changes in cell surface uPAR expression. By gel mobility shift and UV-cross linking assays, a uPAR mRNA binding protein (uPAR mRNABp) implicated in the posttranscriptional control of message stability, was identified in each of the cell lines. Expression of uPAR and its message in cultured lung carcinoma and malignant mesothelioma cells is similarly influenced by effectors present in the tumor microenvironment. Regulation of the uPAR message occurs at the posttranscriptional level in cultured small and non-small cell lung carcinoma cells as well as spindle-shaped and fibrous malignant mesothelioma cell lines. Posttranscriptional regulation of uPAR in all these cells involves the interaction of the uPAR mRNABp with uPAR mRNA, which promotes uPAR mRNA destabilization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006914800447
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  • 62
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    Transcriptional modulation of the human complement factor I gene in Hep G2 cells by protein kinase C activation (1999)
    Springer
    Molecular and cellular biochemistry 201 (1999), S. 111-123 
    Details
    ISSN: 1573-4919
    Keywords: complement factor I ; TPA ; protein kinase C ; gene expression ; Hep G2 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract This study examined the role of the protein kinase C (PKC) signalling pathway in the regulation of expression of human complement factor I (CFI) gene. The production of CFI by Hep G2 cells was enhanced in a dose- and time-dependent fashion by 12-O-tetradecanoyl-1,2-phorbol 13-acetate (TPA), a potent PKC activator. 4α-phorbol didecanoate, an inactive phorbol ester, had no effect on CFI synthesis. The TPA-dependent increase in CFI secretion was correlated with an increase in CFI mRNA levels. Forskolin, a cAMP-inducing agent, augmented the TPA response. W7, an inhibitor of protein kinase A and genistein, an inhibitor of protein tyrosine kinase(s) both did not prevent the increase in CFI expression mediated by TPA. However, calphostin C, a specific inhibitor of PKC, abolished the TPA-induced increase in CFI mRNA levels. Down regulation of intracellular PKC levels by prior exposure of Hep G2 cells to a high concentration of TPA also blocked the increase in CFI mRNA levels induced by TPA suggesting that the TPA effects were mediated via activation of PKC. mRNA decay studies indicated that the half-life of CFI mRNA in TPA-induced cells was not significantly different from control. Nuclear run-on transcriptional assays on the other hand demonstrated that whereas the CFI gene is transcribed under basal conditions in Hep G2 cells, TPA induced a 3-4 fold increase in the transcription rate of CFI gene in 24 h. The transcription rate of GAPDH gene did not change, indicating that the effects were not general on gene transcription. Transient transfections of Hep G2 cells with chloramphenicol acetyltransferase reporter gene (CAT) constructs containing a series of sequential 5′ deletions of the CFI promoter and CAT assays showed that the sequence between -136 and -130, containing an AP-1 consensus sequence (TGAGTCA) was required for the TPA response. This observation was substantiated by the finding that mutation of this AP-1 site to TttaTCA or TtAtcCA abolished the TPA responsiveness. The enhancement of the activity of transfected chimeric CAT constructs by TPA was abrogated by calphostin C and by pyrrolidine dithiocarbamate (an inhibitor of NF-κB and AP-1 transactivation). These results indicate that TPA regulation of CFI gene requires PKC signalling and is mediated by via a TPA response element (TRE) in the CFI promoter region located at -136/-130 and involves the transactivation of AP-1 and NF-κB transcription factors. We suggest that PKC may be one of the intracellular pathways that control CFI gene expression and that cellular processes (involving growth factors, hormones, cytokines etc.) that activate PKC may upregulate the expression of the CFI gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007064602321
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  • 63
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    Electronic Resource
    Expression of calcium-binding protein regucalcin and microsomal Ca2+-ATPase regulation in rat brain: Attenuation with increasing age (1999)
    Springer
    Molecular and cellular biochemistry 200 (1999), S. 43-49 
    Details
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; gene expression ; Ca2+-ATPase ; brain microsomes ; aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The expression of calcium-binding protein regucalcin and its effect on the microsomal Ca2+-ATPase activity in rat brain tissues was investigated. The expression of regucalcin mRNA was demonstrated by reverse transcription-polymerase chain reaction (RT-PCR) analysis in brain tissues using rat regucalcin-specific primers. Regucalcin concentration in the brain tissues was about 5 × 10-9 M as measured using enzyme-linked immunoadsorbent assay (ELISA), and this level was lowered with increasing age (50 weeks old). The presence of regucalcin (10-9 to 10-7 M) in the enzyme reaction mixture caused a significant decrease in Ca2+-ATPase activity in the brain microsomes of young rats (5 weeks old). Meanwhile, the enzyme activity was not significantly altered by the addition of calmodulin (1 or 50 μg/ml), calbindin (1 or 10 μg/ml), and S-100 A protein (5 or 25 μg/ml), which are other Ca2+-binding proteins in rat brain. The effect of regucalcin to inhibit microsomal Ca2+-ATPase activity was weakened in the brain of rats with increasing age (50 weeks old). The present study demonstrates that regucalcin is expressed in the brain, and that it can uniquely inhibit Ca2+-ATPase activity in the brain microsomes of rats. The findings suggest that regucalcin plays a role in the regulation of microsomal Ca2+-ATPase activity in rat brain tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006928402184
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  • 64
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    Electronic Resource
    Identification of stretch-responsive genes in pulmonary artery smooth muscle cells by a two arbitrary primer-based mRNA differential display approach (1999)
    Springer
    Molecular and cellular biochemistry 197 (1999), S. 87-96 
    Details
    ISSN: 1573-4919
    Keywords: mechanical stretch ; smooth muscle cells ; differential display ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Physical forces induce profound changes in cell phenotype, shape and behavior. These changes can occur in vascular structures as a result of pressure overload and their effects can be seen in atherosclerotic vessels in which smooth muscle cells have undergone hyperplastic and hypertrophic changes. At the molecular level, mechanical stimuli are converted into chemical ones and lead to modulation of gene expression and/or the activation of a new repertoire of genes whose encoded proteins help the cells to adapt to their microenvironment. In this study, we have used a two primer-based mRNA differential display technique to identify candidate mechano-responsive genes in pulmonary artery smooth muscle cells. As compared to the original method described by Liang and Pardee, this technique uses two arbitrary primers instead of an anchored oligo(dt) plus an arbitrary primer in the polymerase chain reaction. The chief advantages of these modifications are an increase in the efficiency of the amplification and in the identification of differentially expressed clones. Using this approach, we compared the pattern of expressed genes in cells cultured under static conditions with those in cells that were mechanically stretched (1 Hz) for 24 h in a well-defined in vitro mechanical system. Three candidate genes that showed reproducible differences were chosen for further characterization and cloning. One clone was under expressed in stretched cells and had a DNA sequence with 90% homology to the human fibronectin gene. Two other clones were highly expressed in stretched cells and had a 92% and a 83% sequence homology with human platelet-activating factor (PAF) receptor and rat insulin-like growth factor-I (IGF-I) genes respectively. Northern blot analysis confirmed low levels of fibronectin mRNA transcripts in stretched cells. In contrast, accumulation of PAF receptor mRNA occurred 30 min after mechanical stretch was initiated whereas IGF-I mRNA levels peaked at 8 h. Both mRNA levels were sustained for up to 24 h of mechanical stretching. These results demonstrate the usefulness of the two primer-based mRNA differential display that enabled us to identify and characterize alterations at the level of gene expression among matrix proteins, G-protein coupled receptors and growth factors, each of whose response to mechanical strain is different. A more complete understanding of these responses will provide further insight into the pathologic processes associated with hypertension and atherosclerosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006966530553
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  • 65
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    Electronic Resource
    Amino acids in rinse effluents as a predictor of graft function after transplantation of fatty livers in rats (1999)
    Springer
    Transplant international 12 (1999), S. 168-175 
    Details
    ISSN: 1432-2277
    Keywords: Key words Liver transplantation ; Survival ; Amino acids ; Organ preservation ; Primary nonfunction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract There are too few reliable markers by which one can predict future function of a liver before implantation. Consequently, the purpose of this study was to test the hypothesis that amino acids in rinse–effluents could predict transplant outcome in marginal fatty livers from rats. Amino acids were measured in the rinse effluent from the livers immediately after harvest and graft preparation or cold storage. Amino acids in the effluent were twice as high in ethanol-treated animals compared to those in nonfatty controls. Ethanol-treated fatty livers survived for no longer than 7 days after transplantation while 83 % of nonfatty controls survived (P 〈 0.05). In subsequent studies, the cold-storage time was decreased to 6 h to determine whether failing fatty livers released more amino acid than grafts that would function normally. There was a significant increase in amino acids in the effluent of fatty grafts compared to controls. Moreover, the sum of the four selected amino acids (alanine, valine, histidine, leucine) was lower than 23 nmol/g liver in functional livers, whereas failing grafts had totals significantly higher than 25 nmol/g liver. The sum of the four amino acids correlated well with 24 h post-transplant serum AST levels (r = 0.78, P 〈 0.0001). So we can conclude that amino acid release can serve as a useful marker of graft viability and reliably predicts survival.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001470050206
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  • 66
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    Electronic Resource
    Prediction of solvent accessibility of amino acid residues: critical aspects (1999)
    Springer
    Theoretical chemistry accounts 101 (1999), S. 186-193 
    Details
    ISSN: 1432-2234
    Keywords: Key words: Solvent accessibility ; Logistic function ; Hydrophobicity ; Burial index ; Amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract. For predicting solvent accessibility from the sequence of amino acids in proteins, we use a logistic function trained on a non-redundant protein database. Using a principal component analysis, we find that the prediction can be considered, in a good approximation, as a monofactorial problem: a crossed effect of the burial propensity of amino acids and of their locations at positions flanking the amino acid of interest. Complementary effects depend on the presence of certain amino acids (mostly P, G and C) at given positions. We have refined the predictive model (1) by adding supplementary input data, (2) by using a strategy of prediction correction and (3) by adapting the decision rules according to the amino acid type. We obtain a best score of 77.6% correct prediction for a relative accessibility of 9%. However, compared to trivial strategy only based upon the frequencies of buried or exposed residues, the gain is less than 4%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002140050428
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  • 67
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    Electronic Resource
    Characterisation of genes isolated from a potato swellingstolon cDNA library (1999)
    Springer
    Potato research 42 (1999), S. 31-42 
    Details
    ISSN: 1871-4528
    Keywords: Solanum tuberosum L. ; tuberisation ; extensin ; acyl carrier protein thioesterase ; high mobility group protein ; gene expression ; plant development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In screening to isolate a full-length copy of a previously isolated cDNA clone, a further three cDNAs were also isolated from a library prepared from sub-apical swelling-stolon tissue of potato (Solanum tuberosum L.). Sequence analysis showed these clones to be similar to extensin-like protein genes, acyl carrier protein thioesterase genes and high mobility group protein genes, respectively. A further cDNA, isolated by subtractive hybridisation, was similar to a tomato cDNA previously isolated on the basis of its down-regulation following nematode infection. While all the newly isolated genes were expressed in swelling stolons, for most, maximal expression was seen to be in stem tissue. Possible roles for these genes in the development of potato plants are discussed, as is the significance of gene expression in stems and stolons to the process of tuberisation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02358389
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  • 68
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    Electronic Resource
    Introduction of a Proximal Stat5 Site in the Murine α-Lactalbumin Promoter Induces Prolactin Dependency In Vitro and Improves Expression Frequency In Vivo (1999)
    Springer
    Transgenic research 8 (1999), S. 23-31 
    Details
    ISSN: 1573-9368
    Keywords: transgenic mice ; prolactin ; mammary gland ; gene expression ; Stat5 ; β-globin insulator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to establish a possible correlation between in vitro prolactin induction and the transcriptional activity of mammary gene promoters in transgenic mice, a functional Stat5-binding site was created by means of site-directed mutagenesis at position −70 on a 560 bp murine α-lactalbumin promotor linked to a CAT reporter gene. Surprisingly, the wild-type promoter was constitutively active in vitro and could not be induced by prolactin. Introducing the proximal Stat5 site abolished this constitutive activity and resulted in prolactin dependence in both CHO-K1- and HC11-transfected cells. In transgenic mice, both the frequency of lines expressing the transgene and the prevalence of mid to late pregnancy expression were increased.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008851802022
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  • 69
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    Effect of acute and chronic exercise on plasma amino acids and prolactin concentrations and on [3H]ketanserin binding to serotonin2A receptors on human platelets (1999)
    Springer
    European journal of applied physiology 79 (1999), S. 318-324 
    Details
    ISSN: 1439-6327
    Keywords: Key words Endurance exercise ; Amino acids ; Serotonin ; Central fatigue ; Overtraining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) has been shown to modulate various physiological and psychological functions such as fatigue. Altered regulation of the serotonergic system has been suggested to play a role in response to exercise stress. In the present study, the influence was investigated of acute endurance exercise and short-term increase in the amount of training on the concentrations of the 5-HT precursor tryptophan (TRP), of prolactin (PRL) and of branched-chain amino acids (BCAA) in the blood, as well as on the binding of [3H]ketanserin to the serotonin-2A (5-HT2A) receptors on platelets. Nine healthy endurance-trained men were tested the day before (I) and after (II) a 9-day training programme. Samples of venous blood were drawn after an overnight fast and following 5 h of cycling. Fasted and post-exercise plasma concentrations of free TRP, BCAA and free TRP:BCAA ratio did not differ between I and II. A significant decrease of plasma BCAA (P 〈 0.01) and significant augmentations of plasma free TRP, free TRP:BCAA ratio and PRL (P 〈 0.01) were found post-exercise. The increase in plasma PRL was smaller in II compared with I. Acute endurance exercise reduced the density of platelet 5-HT2A receptor [3H]ketanserin binding sites at I and II (P 〈 0.05). The basal density of the binding sites and the affinity of [3H]ketanserin for these binding sites were unaffected by an increase in the amount of training. The present results support the hypothesis that acute endurance exercise may increase 5-HT availability. This was reflected in the periphery by increased concentration of the 5-HT precursor free TRP, by increased plasma PRL concentration, and by a reduction of 5-HT2A receptors on platelets. It remains to be resolved whether these alterations in the periphery occur in parallel with an increase in the availability of 5-HT in the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004210050514
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  • 70
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    Electronic Resource
    Quantitative analysis of transcription and translation in gene amplified Chinese hamster ovary cells on the basis of a kinetic model (1999)
    Springer
    Cytotechnology 29 (1999), S. 93-102 
    Details
    ISSN: 1573-0778
    Keywords: CHO cells ; gene expression ; kinetic model ; protein secretion ; transcription ; translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The elevation of expression levels for secreted glycoproteins by gene amplification in mammalian cells shows a saturation behavior at high levels of gene amplification. At high expression levels a drop in the secretion efficiency for the recombinant protein occurs (Schröder and Friedl, 1997), coinciding with the appearance of misfolded protein in the cell. In this communication we investigated whether additional limitations exist at the levels of transcription and translation. Four Chinese hamster ovary (CHO) cell lines expressing different amounts of human antithrombin III (ATIII) were used as a model system. A tenfold increase in the ATIII cDNA copy number from the lowest to the highest producing cell line coincided with a 38-fold increase in ATIII mRNA levels, and an 80-fold increase in the amount of intracellular ATIII levels. The data was analyzed using a simple kinetic model. The following conclusions were derived: I. The transcriptional activity for the recombinant protein is not saturated. II. Translation itself is not saturated either, but may be downregulated as secretion efficiency drops. III. Two explanations for the previously reported drop in secretion efficiency for the recombinant protein with increasing expression level are possible: A. Protein degradation is an alternative fate for translated ATIII and the fraction of ATIII degraded after translation increases as expression level is increased. B. Translation is downregulated as the secretory apparatus becomes exhausted to maintain cell viability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008077603328
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    Embryonic stem cell differentiation models: cardiogenesis, myogenesis, neurogenesis, epithelial and vascular smooth muscle cell differentiation in vitro (1999)
    Springer
    Cytotechnology 30 (1999), S. 211-226 
    Details
    ISSN: 1573-0778
    Keywords: cardiogenesis ; cell differentiation ; gene expression ; mouse embryonic stem cells ; myogenesis ; neurogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Embryonic stem cells, totipotent cells of the early mouse embryo, were established as permanent cell lines of undifferentiated cells. ES cells provide an important cellular system in developmental biology for the manipulation of preselected genes in mice by using the gene targeting technology. Embryonic stem cells, when cultivated as embryo-like aggregates, so-called ‘embryoid bodies’, are able to differentiate in vitro into derivatives of all three primary germ layers, the endoderm, ectoderm and mesoderm. We established differentiation protocols for the in vitro development of undifferentiated embryonic stem cells into differentiated cardiomyocytes, skeletal muscle, neuronal, epithelial and vascular smooth muscle cells. During differentiation, tissue-specific genes, proteins, ion channels, receptors and action potentials were expressed in a developmentally controlled pattern. This pattern closely recapitulates the developmental pattern during embryogenesis in the living organism. In vitro, the controlled developmental pattern was found to be influenced by differentiation and growth factor molecules or by xenobiotics. Furthermore, the differentiation system has been used for genetic analyses by ‘gain of function’ and ‘loss of function’ approaches in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008041420166
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  • 72
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    Electronic Resource
    Transient gene expression in mammalian cells grown in serum-free suspension culture (1999)
    Springer
    Cytotechnology 30 (1999), S. 71-83 
    Details
    ISSN: 1573-0778
    Keywords: gene expression ; HEK293(EBNA) cells ; serum-free ; transient transfection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In order to establish a simple and scaleable transfection system we have used the cationic polymer polyethylenimine (PEI) to study transient transfection in HEK293 and 293(EBNA) cells grown in serum-free suspension culture. The transfection complexes were made directly within the cell culture by consecutively adding plasmid and PEI (direct method). Alternatively, the DNA-PEI transfection complexes were prepared in fresh medium (1/10 culture volume) and then added to the cells (indirect method). The results of this study clearly show that the ratio of PEI nitrogen to DNA phosphate is very important for high expression levels. The precise ratio is dependent on the DNA concentration. For example, using 1 μg/ml DNA by the indirect method, the ratio of optimal PEI:DNA was about 10–13:1. However, the ratio increases to 33:1 for 0.1–0.2 μg/ml DNA. By testing several different molecular weights of the polycationic polymer we could show that the highest transfection efficiency was obtained with the PEI 25 kDa. Using PEI 25 kDa the indirect method is superior to the direct addition because significantly lower DNA concentrations are needed. The expression levels of the soluble human TNF receptor p55 are even higher at low DNA compared to 1 μg/ml plasmid. The EBV-based pREP vectors gave better transient gene expression when used in 293(EBNA) cells compared to HEK293 cells in suspension culture. No differences in expression levels in the two cell lines were observed when the pC1 (CMV)-TNFR was used. In conclusion, PEI is a low-toxic transfection agent which provides high levels of transient gene expression in 293(EBNA) cells grown in serum-free suspension culture. This system allows highly reproducible, cost-effective production of milligram amounts of recombinant proteins in 2–5 l spinner culture scale within 3–5 days. Fermentor scale experiments, however, are less efficient because the PEI-mediated transient tranfection is inhibited by conditioned medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008000327766
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  • 73
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    Electronic Resource
    The role of the cell cycle in determining gene expression and productivity in CHO cells (1999)
    Springer
    Cytotechnology 30 (1999), S. 49-57 
    Details
    ISSN: 1573-0778
    Keywords: cell cycle ; CHO ; flow cytometry ; gene expression ; synchronisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Understanding the relationships between cell cycle and protein expression is critical to the optimisation of media and environmental conditions for successful commercial operation of animal cell culture processes. Using flow cytometry for the analysis of the early phases of synchronised batch cultures, the dependency of product expression on cell cycle related events has been evaluated in a recombinant CHO cell line. Although the production of recombinant protein is initially found to be cell cycle related, the maximum specific protein productivity is only achieved at a later stage of the exponential phase which also sees a maximum in the intracellular protein concentration. Subsequent work suggests that it is the batch phase/medium composition of cultures which is the major determinant of maximum specific productivity in this cell line. Furthermore the effect of the positive association between S phase and specific productivity is subordinate to the effect of batch phase/medium composition on the specific productivity of batch cultures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008093404237
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  • 74
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    Electronic Resource
    Differential expression of RAB5A in human lung adenocarcinoma cells with different metastasis potential (1999)
    Springer
    Clinical & experimental metastasis 17 (1999), S. 213-219 
    Details
    ISSN: 1573-7276
    Keywords: gene expression ; immunohistochemistry ; mRNA DD ; neoplasia metastasis ; RAB5A
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract For the sake of better understanding the molecular mechanism of neoplasia, we have used the mRNA differential display technique to analyze two human lung adenocarcinoma cell lines, AGZY83-a and Anip973. Anip973 was isolated from AGZY83-a, but manifested much higher metastatic potential than the parent line. We found that a significant differential cDNA fragment in Anip973 was over-expressed, then over-expressed cDNA fragment was cloned and sequenced. It showed that the over-expressed cDNA in Anip973 was RAB5A cDNA. And the RAB5A cDNA sequence was corresponding between the two cells. To determine whether RAB5A may be differentially expressed in the two human lung adenocarcinoma cells at protein level, we further detected RAB5A protein in the two cells by using immunofluorescent method. RAB5A protein was upregulated in highly metastatic Anip973. We also detected the difference in RAB5A gene expression at RNA level in human non-small cell lung carcinoma by RT-PCR. Using immunohistochemical staining, we also examined RAB5A change at protein level in 45 cases human non-small cell lung carcinoma paraffin sections. The results proved the evidence of upregulation of RAB5A in malignant tumor, indicated over-expression of RAB5A gene was correlated with the malignant degree and metastatic potential of lung cancer(χ2 test, p 〈0.01). The RAB5A gene is a member of RAS superfamily, which can transcribe GTP-binding protein that plays an important role in signal transduction of protein trafficking at the cell surface and GDP/GTP cycle in the regulation of endocytotic membrane traffic. Thus our results indicated that over-expression of the RAB5A gene was involved in the process of transformation from AGZY83-a to the higher metastatic cell line Anip973. The result may be a powerful experimental evidence that over-expression of RAB5A gene associated with neoplasia metastasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006617016451
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  • 75
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    Electronic Resource
    Effect of Portacaval Anastomosis on Glutamine Synthetase Protein and Gene Expression in Brain, Liver and Skeletal Muscle (1999)
    Springer
    Metabolic brain disease 14 (1999), S. 273-280 
    Details
    ISSN: 1573-7365
    Keywords: glutamine synthetase ; gene expression ; portacaval anastomosis ; hepatic encephalopathy ; liver ; skeletal muscle ; ammonia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of chronic liver insufficiency resulting from end-to-side portacaval anastomosis (PCA) on glutamine synthetase (GS) activities, protein and gene expression were studied in brain, liver and skeletal muscle of male adult rats. Four weeks following PCA, activities of GS in cerebral cortex and cerebellum were reduced by 32% and 37% (p〈0.05) respectively whereas GS activities in muscle were increased by 52% (p〈0.05). GS activities in liver were decreased by up to 90% (p〈0.01), a finding which undoubtedly reflects the loss of GS-rich perivenous hepatocytes following portal-systemic shunting. Immunoblotting techniques revealed no change in GS protein content of brain regions or muscle but a significant loss in liver of PCA rats. GS mRNA determined by semi-quantitative RT-PCR was also significantly decreased in the livers of PCA rats compared to sham-operated controls. These findings demonstrate that PCA results in a loss of GS gene expression in the liver and that brain does not show a compensatory induction of enzyme activity, rendering it particularly sensitive to increases in ammonia in chronic liver failure. The finding of a post-translational increase of GS in muscle following portacaval shunting suggests that, in chronic liver failure, muscle becomes the major organ responsible for the removal of excess blood-borne ammonia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020741226752
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  • 76
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    Electronic Resource
    Differentiation Dependent Activation of the Myelin Genes In Purified Oligodendrocytes is Highly Resistant to Hypoglycemia (1999)
    Springer
    Metabolic brain disease 14 (1999), S. 189-195 
    Details
    ISSN: 1573-7365
    Keywords: Oligodendrocyte cultures ; glucose ; gene expression ; malic enzyme ; membrane synthesis ; myelination ; undernutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have previously demonstrated that the developmental upregulation of myelin-specific genes in mixed glial cultures is strongly attenuated by hypoglycemia. The present study was designed to evaluate the effect of hypoglycemia on differentiation-dependent upregulation of myelin genes in purified oligodendrocyte cultures. The expression of major myelin protein genes, i.e., proteolipid protein (PLP), basic protein (BP) and myelin associated glycoprotein (MAG) were monitored by Northern blot analysis. In control cultures maintained at 6 mg/ml of glucose, the expression of all the genes upregulated rapidly, and plateaued at approximately day 4. A similar pattern of differentiation-dependent upregulation was observed for the gene encoding a lipogenic enzyme, i.e., malic enzyme (ME). In contrast to mixed glial cultures, however, this developmental gene upregulation was not significantly affected by severe hypoglycemia (approximately 0.02 mg/ml). The results indicate that the effect of glucose deprivation on oligodendrocyte genes observed in mixed glial cultures is mediated by other cells. The upregulation of the genes in differentiating oligodendrocytes was accompanied by the production of myelin-related membrane that was isolated by density gradient fractionation. In contrast to the effect on gene expression, this anabolic activity was highly dependent on glucose, as seen from a profound suppression by severe hypoglycemia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020614809546
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  • 77
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    Electronic Resource
    Genetic Variation in Spiroplasma citri (1999)
    Springer
    European journal of plant pathology 105 (1999), S. 519-533 
    Details
    ISSN: 1573-8469
    Keywords: genome ; gene expression ; mollicute ; recombination ; transposition ; virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Spiroplasmas are members of the Class Mollicutes, wall-less prokaryotes having a high adenosine–thymidine content in their small genomes. Spiroplasma citri is a plant pathogen that inhabits phloem. Like other phytopathogenic spiroplasmas and the related phytoplasmas, it is transmitted from plant to plant by phloem-feeding leafhoppers that serve as alternate hosts for the spiroplasma as well as vectors. Genetic information in spiroplasmas is carried on a circular chromosome, on plasmids and/or in virus genomes. A picture emerging from recent research on the S. citri genome is one of frequent and often extensive variation, resulting from a number of different mechanisms. Expansion and contraction events must continually be occurring in about equal proportions so that the net genome size varies within defined boundaries. Particularly impressive are large changes in genome size that can occur in only a few generations. As with most organisms, genetic variation in S. citri results from variation in extrachromosomal DNA content, changes due to DNA replication and repair processes and changes due to recombination. The implied flux of genetic information into and out of the S. citri genome should be beneficial to the bacterium, allowing it, with its small genome size, to adapt to new environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008757716803
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  • 78
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    Electronic Resource
    Evidence of Mucin Secretion in Human Lung Adenocarcinoma Cell Lines NCIH650 and NCIH2077 and Effect of Select Secretagogues on Mucin Secretion (1999)
    Springer
    Bioscience reports 19 (1999), S. 473-483 
    Details
    ISSN: 1573-4935
    Keywords: Mucin ; lung cancer ; gene expression ; secretion ; lung adenocarcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Mucins comprise an important class of tumor-associated antigens. The objectives of the present study were (a) to establish an in vitro model system using human non-small cell lung adenocarcinoma cell lines NCIH650 and NCIH2077 (b) provide evidence that these cell lines secrete mucin in culture conditions and (c) investigate the effects of select secretagogues on mucin secretion. The cell lines were established in ACL-4 medium containing several growth factors and retinoic acid and 5% fetal calf serum. The high molecular weight glycoconjugates secreted in the culture medium were purified by ammonium sulfate precipitation and Superose 6 and Superose 12 FPLC chromatography. The purified high molecular weight glycoconjugate fraction and the carcinoma cells were shown to have mucin by dot blot, Western blot and immunohistochemical analysis, respectively, using specific antibodies to purified major mucin, HTM-1. Also, incorporation experiments with mucin precursor 3H-glucosamine demonstrated that the cells indeed synthesize high molecular weight mucins. The effects of secretagogues such as, 8-bromocyclic AMP, ionomycin, phorbol-12-myristate-13-acetate and neutrophil elastase on mucin secretion were also investigated. Only 8-bromocyclic AMP and neutrophil elastase influenced mucin secretion. These studies provided strong evidence that the lung adenocarcinoma cell lines secrete high molecular weight mucins in culture conditions and only two of the four tested secretagogues significantly increased mucin secretion. Thus, this in vitro model system may be useful in determining alterations in mucin structure, if any, in lung adenocarcinomas as well as in studying the regulation of mucin gene expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020224625088
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  • 79
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    Possible nutritional implications of varietal influence on the 7S/11S seed globulin ratios in Amaranth (1999)
    Springer
    Plant foods for human nutrition 54 (1999), S. 375-380 
    Details
    ISSN: 1573-9104
    Keywords: 7S/11S ratios ; Amaranth ; Amino acids ; Nutrition ; Varieties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract 7S/11S seed globulin ratios were determined for sevencurrently available Amaranthus hybrid linesi.e., Amaranthus K266, K283, K343, K432, K433,K436 and MT-3. Of the seven Amaranthus linesinvestigated, four lines had 7S/11S globulin ratiosranging from 0.47 to 0.81, while three lines werefound to contain exclusively the 11S globulin form. In general, 7S globulins contained lower levels ofessential amino acids such as tryptophan, methionine,lysine, histidine, phenylalanine, valine andisoleucine than the 11S globulins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008153925283
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  • 80
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    Electronic Resource
    Agglutinating activity of alcohol-soluble proteins from quinoa seed flour in celiac disease (1999)
    Springer
    Plant foods for human nutrition 54 (1999), S. 93-100 
    Details
    ISSN: 1573-9104
    Keywords: Amino acids ; Celiac disease ; Cells ; Cereals ; Prolamines ; Quinoa seeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The edible seeds of the quinoa plant contain small quantities of alcohol-soluble protein which, after peptic-tryptic digestion, are unable to agglutinate K562(s) cells. When separated by affinity chromatography on sepharose-6B coupled with mannan, peptic-tryptic digest separated in two fractions. Fraction B peptides (about 1% of total protein) were shown to agglutinate K562(s) cells at a very low concentration, whereas peptides in fraction A and in the mixed fraction A+B were inactive, suggesting that fraction A contains protective peptides that interfere with the agglutinating activity of toxic peptides in fraction B.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008059519025
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  • 81
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    Comparison of the Anticancer Effect of Free and HPMA Copolymer-Bound Adriamycin in Human Ovarian Carcinoma Cells (1999)
    Springer
    Pharmaceutical research 16 (1999), S. 986-996 
    Details
    ISSN: 1573-904X
    Keywords: adriamycin ; doxorubicin ; HPMA copolymer ; apoptosis, multidrug resistance ; gene expression ; signal transduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To study peculiarities and the mechanism of the anticancer effect of free and HPMA copolymer-bound ADR in sensitive and resistant human ovarian carcinoma cells. Methods. Sensitive A2780 and ADR resistant A2780/AD cells were exposed to different doses of drugs during 12, 24, 36, 48, 60, and 72 hours. Cell viability, drug accumulation, apoptosis, cellular metabolism, lipid peroxidation, DNA content and gene expression were studied. Results. HPMA copolymer-bound ADR (P(GFLG)-ADR) possessed a comparable cytotoxicity to free ADR when comparison was based on intracellular concentrations. While free ADR up-regulated genes encoding ATP driven efflux pumps (MDR1, MRP), P(GFLG)-ADR overcame existing pumps and down regulated the MRP gene. Free ADR also activated cell metabolism and expression of genes responsible for detoxification and DNA repair. P(GFLG)-ADR down-regulated HSP-70, GSr-π, BUDP, Topo-IIα, β, and TK-1 genes. Apoptosis, lipid peroxidation and DNA damage were significantly higher after exposure to P(GFLG)-ADR, as reflected by simultaneous activation of p53, c-fos in A2780 cells) or c-jun (A2780/AD) signaling pathways and inhibition of the bcl-2 gene. Differences between free ADR and P(GFLG)-ADR increased with the time of incubation and drug concentration. Conclusions. P(GFLG)-ADR overcame drug efflux pumps, more significantly induced apoptosis and lipid peroxidation, inhibited DNA repair, replication, and biosynthesis when compared to free ADR.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018959029186
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  • 82
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    Chemical analysis and nutritional assessment of Teramnus labialis (L.) Spreng. (Fabaceae) (1999)
    Springer
    Plant foods for human nutrition 54 (1999), S. 345-352 
    Details
    ISSN: 1573-9104
    Keywords: Amino acids ; Antinutritional factors ; Protein fractionation ; Proximate composition ; Teramnus labialis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seeds of Teramnus labialis (L.) Spreng.(Fabaceae), used as food by Malayali tribals in theKollihills of Salem District, Tamil Nadu in SouthIndia, were investigated for their nutritional value. These seeds were analyzed for proximate composition,total (true) seed proteins, seed proteinfractions, amino acid composition, fatty acidcomposition, minerals and antinutritional factors. Crude protein, crude fat, ash, and nitrogen freeextracts constituted 22.86%, 6.10%, 4.62%, and,58.15%, respectively, of the seed weight. The caloricvalue of 100 g dry matter of seed material was 378.94kcal. The essential amino acids lysine, leucine +isoleucine, arginine, valine and histidine werepresent in relatively large quantities. Theunsaturated fatty acids constituted more than 60% ofthe crude fat. Concentrations of minerals such aspotassium, magnesium, calcium, and, phosphorus werehigh. Antinutritional factors such as total freephenols, tannins, L-DOPA, hydrogen cyanide andphytic acid were present in minute quantities. Theseantinutritional factors are potentially eliminated using the conventional method of soaking the seeds in water,boiling with water and decanting prior to consumption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008101805505
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  • 83
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    Electronic Resource
    Enhanced expression and differential inducibility of soybean chalcone synthase genes by supplemental UV-B in dark-grown seedlings (1999)
    Springer
    Plant molecular biology 39 (1999), S. 785-795 
    Details
    ISSN: 1573-5028
    Keywords: UV-B ; soybean ; chalcone synthase ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By developing gene-specific RT-PCR and using filters to allow transmission down to 290 nm (UV-B+) or blocking all radiation below 320 nm (UV-B−), the effect of UV-B+ and UV-B− light on expression of each of the presently known seven members of soybean chalcone synthase (CHS) gene family in dark-grown seedlings was analyzed. Dark expression was detectable already in 18 h dark-germinating embryos, with progressive increases on successive days, suggesting that chs belongs to a class of genes expressed very early during germination, and that the expression at this stage is either constitutive or induced by non-light-dependent factors present in the seed or made available following imbibition. Exposure of 18 h dark-germinating embryos to UV-B− or to UV-B+ light did not lead to an increase in chs signal. However, the 24 h dark-germinating embryos showed a distinct effect of UV-B+, interestingly coinciding with the stage when the head of seedlings was in the process of being pushed up above ground by stem elongation, suggesting the possibility of a developmental switch modulating the appearance of UV-B response. The response to UV-B− was most prominent in chs1 and almost silent in chs2, while the up-regulation by UV-B+ was most prominent in chs5 and chs6 and much less so in chs2. Interestingly, chs2 was noted to be the only member of the Gmchs gene family devoid of H-box, raising the possibility that the H-box may be a good indicator of the photo-inducibility of a chs gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006124219945
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  • 84
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    Complexity and expression of the glutamine synthetase multigene family in the amphidiploid crop Brassica napus (1999)
    Springer
    Plant molecular biology 39 (1999), S. 395-405 
    Details
    ISSN: 1573-5028
    Keywords: amphidiploid genome structure ; gene expression ; glutamine synthetase ; multigene family ; nitrogen assimilation ; oilseed rape
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the amphidiploid genome of oilseed rape (Brassica napus) the diploid ancestral genomes of B. campestris and B. oleracea have been merged. As a result of this crossing event, all gene loci, gene families, or multigene families of the A and C genome types encoding a certain protein are now combined in one plant genome. In the case of the multigene family for glutamine synthetase, the key enzyme of nitrogen assimilation, six different cDNA sequences were isolated from leaf and root specific libraries. One sequence pair (BnGSL1/BnGSL2) was characterized by the presence of amino- terminal transit peptides, a typical feature of all nuclear encoded chloroplast proteins. Two other cDNA pairs (BnGSR1-1/BnGSR1-2 and BnGSR2-1/BnGSR2-2) with very high homology between each other were found in a root specific cDNA library and represent protein subunits for cytosolic glutamine synthetase isoforms. Comparative PCR amplifications of genomic DNA isolated from B. napus, B. campestris and B. oleracea followed by sequence–specific restriction analyses of the PCR products permitted the assignment of the cDNA sequences to either the A genome type (BnGSL1/BnGSR1- 1/BnGSR2-1) or the C genome type (BnGSL2/BnGSR1-2/BnGSR2-2). Consequently, the ancestral GS genes of B. campestris and B. oleracea are expressed simultaneously in oilseed rape. This result was also confirmed by RFLP (restriction fragment length polymorphism) analysis of RT-PCR products. In addition, the different GS genes showed tissue specific expression patterns which are correlated with the state of development of the plant material. Especially for the GS genes encoding the cytosolic GS isoform BnGSR2, a marked increase of expression could be observed after the onset of leaf senescence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006193717093
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  • 85
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    Diverse range of gene activity during Arabidopsis thaliana leaf senescence includes pathogen-independent induction of defense-related genes (1999)
    Springer
    Plant molecular biology 40 (1999), S. 267-278 
    Details
    ISSN: 1573-5028
    Keywords: defense ; gene expression ; leaf senescence ; nitrilase ; pathogen-free ; salicylic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To determine the range of gene activities associated with leaf senescence, we have identified genes that show preferential transcript accumulation during this developmental stage. The mRNA levels of a diverse array of gene products increases during leaf senescence, including a protease, a ribosomal protein, two cinnamyl alcohol dehydrogenases, a nitrilase and glyoxalase II. Two of the genes identified are known to be pathogen-induced. The senescence specificity of each gene was determined by characterization of transcript accumulation during leaf development and in different tissues. The increased expression of nitrilase in senescent leaves is paralleled by an increase in free indole-3-acetic acid (IAA) levels. Additionally, we have demonstrated that the induction of defense-related genes during leaf senescence is pathogen-independent and that salicylic acid accumulation is not essential for this induction. Our data indicate that the induction of certain genes involved in plant defense responses is a component of the leaf senescence program.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006199932265
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  • 86
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    Isolation and molecular characterization of gibberellin-regulated H1 and H2B histone cDNAs in the leaf of the gibberellin-deficient tomato (1999)
    Springer
    Plant molecular biology 39 (1999), S. 883-890 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; gibberellin ; H1 histone ; H2B histones ; leaf ; Lycopersicon esculentum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract After differential screening we isolated cDNA clones encoding a histone H1 (leH1) and three variants of histone H2B (leH2B-1, -2 and -3) from the gibberellin (GA)-deficient mutant of tomato (gib-1). The deduced polypeptide of leH1 is 271 amino acids long and exhibits the typical tripartite structure of histones H1. The full-length cDNA clone leH2B-1 encodes for a protein of 142 amino residues and shows the tripartite organization of histones H2B. The histones leH1 and leH2B, which show no tissue specificity, are developmentally expressed in the leaf. The mRNA accumulation was higher in organs which contain meristematic tissue and/or which have a high proportion of actively cycling cells. In the leaf of the gib-1 mutant we demonstrated GA-enhanced histone leH1 and leH2B expression which was not observed in the wild type. GAs of the early-13-hydroxylated pathway (GA1 and GA3) caused most enhanced transcription compared to GAs of the early-non-hydroxylation pathway (GA4 and GA9). Application of GA to the mutant increased histone expression that could correlate with enhanced DNA replication in leaf tissue. Increased chromosome replication may indicate that there is a higher rate of cell division and/or increase of endopolyploidy which both may be dependent on cell elongation induced by GAs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006157718263
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  • 87
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    Differential expression of two spermidine synthase genes during early fruit development and in vegetative tissues of pea (1999)
    Springer
    Plant molecular biology 39 (1999), S. 933-943 
    Details
    ISSN: 1573-5028
    Keywords: cloning ; fruit development ; gene expression ; pea ; polyamine ; spermidine synthase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two cDNAs from young pea fruits coding for functional spermidine synthases (EC 2.5.1.16) were isolated. The corresponding genes were named psSPDSYN1 and psSPDSYN2. Both cDNAs complemented spe3Δ gene when introduced into the Y480 strain of Saccharomyces cerevisiae, which is a null mutant for the spermidine synthase gene. psSPDSYN1 and psSPDSYN2 are regulated differentially. psSPDSYN1 is up-regulated early after fruit set whereas psSPDSYN2 is expressed later. Spermidine synthase activity was detected in pea ovaries, and correlates with the pattern of expression of psSPDSYN1. In the pea plant, psSPDSYN1 is highly expressed in actively growing tissues, whereas the highest level of psSPDSYN2 mRNA was detected in fully elongated stem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006158819849
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  • 88
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    Electronic Resource
    Regulation of the chitinase gene expression in suspension-cultured rice cells by N-acetylchitooligosaccharides: differences in the signal transduction pathways leading to the activation of elicitor-responsive genes (1999)
    Springer
    Plant molecular biology 39 (1999), S. 907-914 
    Details
    ISSN: 1573-5028
    Keywords: chitin oligomer ; chitinase ; elicitor ; gene expression ; rice ; signal transduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Expression patterns of chitinase transcripts induced by N-acetylchitooligosaccharide elicitor were analyzed by northern blot hybridization in order to reveal a signal transduction pathway leading to the activation of class I chitinase genes (Cht-1 and Cht-3), which may play an important role in producing N-acetylchitooligosaccharide elicitor. The transcription level of both genes was enhanced in response to N-acetylchitooligosaccharides larger than pentaose at subnanomolar concentrations. These structure and dose dependencies were consistent not only with those for a 75 kDa high-affinity binding protein for N-acetylchitooligosaccharide elicitor in the plasma membrane, but also with other series of cellular responses including phytoalexin production and the expression of elicitor-responsive genes (EL2, EL3). Therefore, the elicitor signal to evoke these cellular responses including the activation of the chitinase genes could be common and transmitted into cells through the 75 kDa protein. However, the signal transduction pathway for the activation of the chitinase gene appeared to diverge from those for the other elicitor-responsive genes shortly after the signal perception. It was shown that the induction of chitinase expression by N-acetylchitooligosaccharide would require protein phosphorylation, but not de novo protein synthesis. The oxidative burst was demonstrated not to be necessary for transcriptional induction of the all four elicitor-responsive genes (Cht, PAL, EL2, EL3) by N-acetylchitooligosaccharide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006161802334
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  • 89
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    Electronic Resource
    Temporal and spatial gene expression of cytochrome B5 during flower and fruit development in olives (1999)
    Springer
    Plant molecular biology 40 (1999), S. 79-90 
    Details
    ISSN: 1573-5028
    Keywords: cytochrome b5 ; fruit and flower development ; gene expression ; in situ hybridisation ; olive
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report the characterisation of two cytochrome b5 genes and their spatial and temporal patterns of expression during development in olive, Olea europaea. A PCR-generated probe, based on a tobacco cytochrome b5 sequence, was used to isolate two full-length cDNA clones (cytochrome b5-15 and cytochrome b5-38) from a library derived from 13 WAF olive fruits. The cDNAs encoded proteins of 17.0 and 17.7 kDa, which contained all the characteristic motifs of cytochromes b5 from other organisms and exhibited 63% identity and 85% similarity with each other. The olive cytochrome b5-15 cDNA was then used as a probe for more detailed analysis. Southern blotting revealed a gene family of at least 4–6 members while northern blotting and in situ hybridisation showed a highly specific pattern of gene expression. Very low levels of cytochrome b5 mRNA were detected in tissues characterised by high rates of lipid accumulation, such as young expanding leaves, maturing seeds and ripening mesocarp. The cytochrome b5 genes were not induced at 6 °C and their response to ABA was relatively slow compared with fatty acid desaturase genes. In contrast, high levels of cytochrome b5 gene expression were found in young fruits at the pattern formation (globular/heart) stage of embryogenesis and in vascular and transmitting tissues of male and female reproductive organs. The data are consistent with a major role for cytochrome b5 in developmental processes related to plant reproduction in addition to being an electron donor to microsomal desaturases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026417710320
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  • 90
    Electronic Resource
    Electronic Resource
    Cloning and characterization of a trypsin inhibitor cDNA from amaranth (Amaranthus hypochondriacus) seeds (1999)
    Springer
    Plant molecular biology 41 (1999), S. 15-23 
    Details
    ISSN: 1573-5028
    Keywords: Amaranthus hypochondriacus) ; gene expression ; trypsin inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We previously isolated and sequenced the major trypsin inhibitor from Amaranthus hypochondriacus seeds. This amaranth trypsin inhibitor (AmTI) is a 69 amino acid protein with high homology to members of the potato-1 inhibitor family. This paper describes the cloning and expression of a cDNA encoding this trypsin inhibitor in various vegetative tissues of the amaranth plant during seed development and imbibition, and investigates the possible induction of AmTI expression by wounding. We obtained a 393 bp cDNA sequence with an open reading frame corresponding to a polypeptide with 76 amino acid residues. With the exception of one residue (Ser-41), the polypeptide agrees with the amino acid sequence previously reported, plus 7 more residues at the N-terminus. These N-terminal residues are thought to be part of the signal used for intracellular sorting. The organ specificity of AmTI gene expression was investigated by northern analysis, showing that mRNA corresponding to AmTI genes was present in stems of plants growing under normal conditions. The kinetics of accumulation of the AmTI-mRNA, protein, and inhibitory activity during seed development and imbibition was determined. AmTI-mRNA accumulation reached a maximum at 14 days after anthesis (daa) and then gradually decreased, being barely detectable 36 daa. The AmTI protein accumulation followed the same profile as the inhibitory activity, both were delayed with respect to the mRNA. The maximum level was observed 22 daa, and then gradually decreased until a steady state was reached as seed maturation proceeded. Upon imbibition, a gradual decrease in AmTI protein and inhibitory activity was shown; however, an AmTI transcript was detected 24 h after imbibition. In contrast to representative members of the potato I family, this inhibitor was not inducible by wounding of leaves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006262106267
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  • 91
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    Electronic Resource
    Localization of peroxidase mRNAs in soybean seeds by in situ hybridization (1999)
    Springer
    Plant molecular biology 41 (1999), S. 57-63 
    Details
    ISSN: 1573-5028
    Keywords: embryo ; gene expression ; Glycine max ; oxidoreductase ; seed coat ; testa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The soybean Ep gene encodes an anionic peroxidase enzyme that accumulates in large amounts in seed coat tissues. We have isolated a second peroxidase gene, Prx2, that is also highly expressed in developing seed coat tissues. Sequence analysis of Prx2 cDNA indicates that this transcript encodes a cationic peroxidase isozyme that is far removed from Ep in peroxidase phylogeny. To determine the expression patterns for these two peroxidases in developing seeds, the abundance and localization of the Ep and Prx2 transcripts were compared by in situ hybridization. Results show the expression of Ep begins in a small number of cells flanking the vascular bundle in the seed coat, spreads to encircle the seed, and then migrates to the hourglass cells as they develop. Expression of Prx2 occurs throughout development in all cell layers of the seed coat, and is also evident in the pericarp and embryo. Nonetheless, the Ep-encoded enzyme accounts for virtually all of the peroxidase activity detected in mature seed coats. The Prx2 enzyme is either insoluble in a catalytically inactive form, or is subject to degradation during seed maturation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006244500951
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  • 92
    Electronic Resource
    Electronic Resource
    Constitutive protein-DNA interactions on the abscisic acid-responsive element before and after developmental activation of the rab28 gene (1999)
    Springer
    Plant molecular biology 41 (1999), S. 529-536 
    Details
    ISSN: 1573-5028
    Keywords: ABRE ; embryogenesis ; G-box ; gene expression ; maize ; protein-DNA interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transcription of the rab28 gene from maize is induced in late embryo development and in response to abscisic acid. We have studied the regulation of the activity of the rab28 promoter in embryos. Two abscisic acid-responsive elements (ABREs) were necessary for expression in embryos of transgenic Arabidopsis and in transient transformation in maize embryos. In vivo footprinting showed that there was protein binding to the ABREs and to other cis elements in the promoter in young embryos before expression of rab28. This shows that the rab28 promoter is in an open chromatin structure before developmental activation. The ABREs are important for the induction and have protein binding in young embryos. Nuclear proteins extracted from embryos before activation of rab28 bound to the ABREs in band shift assays. A complex with different mobility was formed between nuclear proteins and the ABREs after induction of rab28 suggesting a modification of the ABRE-binding factor or an exchange of proteins. The footprints on the ABREs were unaltered by induction with abscisic acid or during developmental activation of rab28. These results indicate that constitutive binding of transcription factor(s) on the ABRE is central in embryonic regulation of the rab28 gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006345113637
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  • 93
    Electronic Resource
    Electronic Resource
    Molecular characterization of a gene for alanine aminotransferase from rice (Oryza sativa) (1999)
    Springer
    Plant molecular biology 39 (1999), S. 149-159 
    Details
    ISSN: 1573-5028
    Keywords: alanine aminotransferase ; gene expression ; GUS expression ; promoter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA clone encoding alanine aminotransferase (AlaAT) has isolated from randomly sequenced clones derived from a cDNA library of maturing rice seeds by comparison to previously identified genes. The deduced amino acid sequence was 88% and 91% homologous to those of the enzymes from barley and broomcorn millet (Panicum miliaceum), respectively. Using this cDNA as a probe, we isolated and sequenced the corresponding genomic clone. Comparison of the sequences of the cDNA and the genomic gene revealed that the coding region of the gene was interrupted by 14 introns 66 to 1547 bp long. Northern and western blotting analyses showed that the gene was expressed at high levels in developing seeds. When the 5′-flanking region between −930 and +85 from the site of initiation of transcription was fused to a reporter gene for β-glucuronidase (GUS) and then introduced into the rice genome, histochemical staining revealed strong GUS activity in the inner endosperm tissue of developing seeds and weak activity in root tips. Similar tissue-specific expression was also detected by in situ hybridization. These results suggest that AlaAT is involved in nitrogen metabolism during the maturation of rice seed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006156214716
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  • 94
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    Electronic Resource
    Differential expression of expansin gene family members during growth and ripening of tomato fruit (1999)
    Springer
    Plant molecular biology 39 (1999), S. 161-169 
    Details
    ISSN: 1573-5028
    Keywords: expansin ; fruit growth ; fruit softening ; gene expression ; Lycopersicon esculentum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract cDNA clones encoding homologues of expansins, a class of cell wall proteins involved in cell wall modification, were isolated from various stages of growing and ripening fruit of tomato (Lycopersicon esculentum). cDNAs derived from five unique expansin genes were obtained, termed tomato Exp3 to Exp7, in addition to the previously described ripening-specific tomato Exp1 (Rose et al. (1997) Proc Natl Acad Sci USA 94: 5955–5960). Deduced amino acid sequences of tomato Exp1, Exp4 and Exp6 were highly related, whereas Exp3, Exp5 and Exp7 were more divergent. Each of the five expansin genes showed a different and characteristic pattern of mRNA expression. mRNA of Exp3 was present throughout fruit growth and ripening, with highest accumulation in green expanding and maturing fruit, and lower, declining levels during ripening. Exp4 mRNA was present only in green expanding fruit, whereas Exp5 mRNA was present in expanding fruit but had highest levels in full-size maturing green fruit and declined during the early stages of ripening. mRNAs from each of these genes were also detected in leaves, stems and flowers but not in roots. Exp6 and Exp7 mRNAs were present at much lower levels than mRNAs of the other expansin genes, and were detected only in expanding or mature green fruit. The results indicate the presence of a large and complex expansin gene family in tomato, and suggest that while the expression of several expansin genes may contribute to green fruit development, only Exp1 mRNA is present at high levels during fruit ripening.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006130018931
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  • 95
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    Electronic Resource
    Isolation and characterization of mRNAs differentially expressed during ripening of wild strawberry (Fragaria vesca L.) fruits (1999)
    Springer
    Plant molecular biology 39 (1999), S. 629-636 
    Details
    ISSN: 1573-5028
    Keywords: cDNA cloning ; fruit ripening ; gene expression ; non-climacteric fruit ; wild strawberry (Fragaria vesca L.)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wild strawberry (Fragaria vesca L.) is an attactive model system for studying ripening in non-climacteric fruit, because of its small diploid genome, its short reproductive cycle, and its capacity for transformation. We have isolated eight ripening-induced cDNAs from this species after differential screening of a cDNA library. The predicted polypeptides of seven of the clones exhibit similarity to database protein sequences, including acyl carrier protein, caffeoyl- CoA 3-O-methyltransferase, sesquiterpene cyclase, major latex protein, cystathionine γ-synthase, dehydrin and an auxin- induced gene. A ninth cDNA clone that was constitutively expressed is predicted to encode a metallothionein-like protein. None of these proteins appear to be directly related to events generally associated with ripening such as cell wall metabolism or the accumulation of sugars and pigments, rather, their putative functions are indicative of the wide range of processes upregulated during fruit ripening.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006179928312
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  • 96
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    Electronic Resource
    Enzymatic activity and gene expression under water stress of phospholipase D in two cultivars of Vigna unguiculata L.Walp. differing in drought tolerance (1999)
    Springer
    Plant molecular biology 39 (1999), S. 1257-1265 
    Details
    ISSN: 1573-5028
    Keywords: cowpea (Vigna unguiculata L.) ; drought ; gene expression ; lipid degradation ; phospholipase D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phospholipase D, a major lipid-degrading enzyme in plants, was studied in two cultivars of Vigna unguiculata L.Walp, differing in their tolerance to drought (cv. EPACE-1, drought-tolerant, and cv. 1183, drought-susceptible). Enzymatic activities, measured with 14C-PC as substrate, increased when plants were submitted to water stress, the increase being much higher in the drought-sensitive cultivar. A 2911 bp cDNA encoding a putative phospholipase D (VuPLD1) was isolated from a cDNA library prepared from V. unguiculata leaves. The deduced amino acid sequence (809 residues) shows 85.5% identity and 91.3% similarity to that of PLD from Ricinus communis. The expression of the VuPLD1 gene in the leaves is differently modulated by water deficit, depending on the intensity of stress and the tolerance or sensitivity of the plants. In the drought-susceptible V. unguiculata cv. 1183, it readily increased under water stress, reaching maximum values at mild water deficit (−1.5 MPa). In the drought-tolerant cv. EPACE-1, VuPLD1 mRNA remained low throughout the whole drought treatment. Dehydration of leaves led to a dramatic increase in transcript level in both cultivars. Changes in protein amounts semi-quantified by immunoblotting correlated well with variations in transcript steady-state level. Taken together, these results showed that phospholipase D in cowpea plants is essentially regulated at the transcriptional level, and that gene expression is strongly stimulated even by moderate water deficit in the drought-sensitive plant. On the contrary, the drought-tolerant plant presents a remarkable stability of PLD gene expression in conditions of water stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006165919928
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  • 97
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    Electronic Resource
    Identification of genes specifically expressed in cauliflower reproductive meristems. Molecular characterization of BoREM1 (1999)
    Springer
    Plant molecular biology 39 (1999), S. 427-436 
    Details
    ISSN: 1573-5028
    Keywords: reproductive development ; gene expression ; subtractive hybridization ; cauliflower
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using the meristems of the cauliflower curd as a source of tissue and a series of subtractive hybridizations and amplification reactions, we have constructed a cDNA library highly enriched in cDNAs expressed in reproductive meristems. The analysis of a sample of 250 clones from this library identified 22 cDNA clones corresponding to genes specifically expressed in these cauliflower meristems. Apart from two clones that corresponded to APETALA1, and two other ones showing similarity to different aminoacyl-tRNA synthetases, the remaining clones showed no similarity to any sequence in the databases and may correspond to novel genes. One of these clones, BoREM1, was further characterized and found to correspond to a gene encoding a protein with features of regulatory proteins that follows a expression pattern very similar to the LEAFY transcripts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006130629100
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  • 98
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    Electronic Resource
    A strong constitutive positive element is essential for the ammonium-regulated expression of a soybean gene encoding cytosolic glutamine synthetase (1999)
    Springer
    Plant molecular biology 39 (1999), S. 551-564 
    Details
    ISSN: 1573-5028
    Keywords: ammonium ; gene expression ; glutamine synthetase ; nodules ; positive element ; promoter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to identify important promoter elements controlling the ammonium-regulated expression of the soybean gene GS15 encoding cytosolic glutamine synthetase, a series of 5′ promoter deletions were fused to the GUS reporter gene. To allow the detection of positive and negative regulatory elements, a series of 3′ deletions were fused to a −90 CaMV 35S promoter fragment placed upstream of the GUS gene. Both types of construct were introduced into Lotus corniculatus plants and soybean roots via Agrobacterium rhizogenes-mediated transformation. Both spectrophotometric enzymatic analysis and histochemical localization of GUS activity in roots, root nodules and shoots of transgenic plants revealed that a strong constitutive positive element (SCPE) of 400 bp, located in the promoter distal region is indispensable for the ammonium- regulated expression of GS15. Interestingly, this SCPE was able to direct constitutive expression in both a legume and non- legume background to a level similar to that driven by the CaMV 35S full-length promoter. In addition, results showed that separate proximal elements, located in the first 727 bp relative to the transcription start site, are essential for root- and root nodule-specific expression. This proximal region contains an AAAGAT and two TATTTAT consensus sequences characteristic of nodulin or nodule-enhanced gene promoters. A putative silencer region containing the same TATTTAT consensus sequence was identified between the SCPE and the organ-specific elements. The presence of positive, negative and organ-specific elements together with the three TATTTAT consensus sequences within the promoter strongly suggest that these multiple promoter fragments act in a cooperative manner, depending on the spatial conformation of the DNA for trans-acting factor accessibility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006169018296
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  • 99
    Electronic Resource
    Electronic Resource
    Cloning and characterization of six embryogenesis-associated cDNAs from somatic embryos of Picea glauca and their comparative expression during zygotic embryogenesis (1999)
    Springer
    Plant molecular biology 39 (1999), S. 859-864 
    Details
    ISSN: 1573-5028
    Keywords: embryo-abundant cDNAs ; gene expression ; gymnosperm ; Picea glauca ; somatic embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Six somatic embryogenesis-associated cDNAs (PgEMB2, 6, 7, 8, 24 and 34) from white spruce (Picea glauca (Moench) Voss) somatic embryos have been characterized. Transcript accumulation during somatic embryo development and subsequent germination related to these genes, indicated that they were developmentally regulated. The transcripts related to clones PgEMB2, 6, 24 and 34 were also detected during zygotic embryo development, but transcripts of clones PgEMB7 and 8 were not. PgEMB24 had a similar gene expression pattern to spruce Em-like late embryo abundant (lea) gene, but other clones had no similarities in gene expression to either spruce lea-like or storage protein genes. Abscisic acid, a stimulator for spruce somatic embryo maturation, did not obviously affect gene expression corresponding to these cDNAs. The predicted proteins are distinguishable from known LEA proteins based on analyses of hydropathy plots, amino acid compositions and deduced protein structures. The similarities of the spruce cDNAs, and protein sequences predicted from these cDNAs, to other sequence data are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006146622614
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  • 100
    Electronic Resource
    Electronic Resource
    Mutation of GT-1 binding sites in the Pr-1A promoter influences the level of inducible gene expression in vivo (1999)
    Springer
    Plant molecular biology 40 (1999), S. 387-396 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; GT-1 ; PR-1a ; PR proteins ; salicylic acid-induced ; transcription factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Infection of Nicotiana tabacum Samsun NN with tobacco mosaic virus (TMV) results in a hypersensitive plant response and leads to systemic acquired resistance (SAR). The induction of SAR is mediated by the plant hormone salicylic acid (SA) and is accompanied by the induced expression of a number of genes including the pathogenesis-related (PR) gene 1a. Previously, it has been found that TMV infection and SA treatment resulted in a reduction of binding of nuclear protein GT-1 to far-upstream regions (−902 to −656) of the PR-1a gene. To test if GT-1 is a negative regulator of PR-1a gene expression, the effects of mutations in the seven putative GT-1 binding sites in this region were studied in vitro using dimethyl sulfate interference footprinting and band shift assays. This showed that at least one of the seven sites is indeed a GT-1 binding site. However, when tested in transgenic plants, the mutations did not result in constitutive expression of the chimeric PR-1a/GUS transgene, while inducible expression after SA treatment was decreased. The results suggest that binding of GT-1-like proteins to far-upstream PR-1a promoter regions indeed influences gene expression. A possible model for GT-1's mode of action in PR-1a gene expression is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006144505121
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