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  • 1990-1994  (971)
  • 1955-1959
  • 1992  (971)
  • Organic Chemistry  (916)
  • gene expression
  • 1
    Electronic Resource
    Electronic Resource
    Expression of an islet regenerating (reg) gene in isolated rat islets: effects of nutrient and non-nutrient growth factors (1992)
    Springer
    Diabetologia 35 (1992), S. 238-242 
    Details
    ISSN: 1432-0428
    Keywords: Islets ; growth factors ; replication ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The expression of a novel regenerating (reg) gene has been reported previously in the regenerating islets of a surgical model of diabetes in rats. We exposed collagenase-isolated rat islets for three days to nutrient and non-nutrient growth factors in minimally supplemented RPMI medium (2.7 mmol/l glucose, 2% fetal calf serum), and investigated the relationship between reg gene expression and islet cell replication. RNA was prepared from half of the islets by homogenisation in guanidinium isothiocyanate followed by phenol/chloroform extraction. Northern/dot blot analyses were used to semi-quantify reg mRNA. Islet cell replication was estimated by culturing the remaining islets in radiolabelled thymidine to determine de novo DNA synthesis. Thymidine uptake was stimulated by the following factors: 11 mmol/l glucose (50% increase); 10% amino acids (126% increase); 10% fetal calf serum (39% increase); 100 ng/ml insulin (45% increase); 250 ng/ml growth hormone (65% increase); 1.5 nmol/l aldosterone (29% increase); 2U/ml platelet derived growth factor (116% increase). The results are expressed as a percentage of the thymidine incorporated into control islets cultured in minimal RPMI (1118±100 (SD) cpm/μg protein, n=15). Increased islet cell replication was paralleled in each case by a clear rise in reg mRNA expression compared to controls. Furthermore, the rank order for reg gene expression was the same as that for thymidine uptake (r=0.90). The present findings suggest a clear association between reg gene expression and islet cell replication in vitro, and are the first to demonstrate reg gene expression in response to individual growth factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400923
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  • 2
    Electronic Resource
    Electronic Resource
    Overexpression and purification of enzymatically active recombinant integrase protein of rous sarcoma virus (1992)
    Springer
    Virus genes 6 (1992), S. 301-306 
    Details
    ISSN: 1572-994X
    Keywords: molecular cloning ; gene expression ; integrase protein ; enzyme purification ; Rous sarcoma virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The carboxy-terminal domain of polymerase gene of Rous sarcoma virus was cloned into an expression vector under the control oflac regulatory elements, resulting in the plasmid pMF1413. Upon isopropyl-β-D-thiogalactopyranoside induction, viral integration (IN) protein was expressed in large quantity inEscherichia coli. The expressed recombinant protein was prepurified by successive washing of the bacterial pellet with 0.1 M NaCl and detergents. Further purification was performed in high yield by standard chromatography methods. The purified enzyme revealed selective DNA cleaving activity on supercoiled plasmid with the LTR-LTR junction fragment. The reaction was metal ion dependent, with a preference for Mn2+ over Mg2+, and showed substrate specificity at 1 mM MnCl2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01702568
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  • 3
    Electronic Resource
    Electronic Resource
    Comparative sequence analysis and expression of bovine PrP gene in mouse L-929 cells (1992)
    Springer
    Virus genes 6 (1992), S. 343-356 
    Details
    ISSN: 1572-994X
    Keywords: Bovine PrP ; cDNA ; nucleotide sequence ; gene expression ; transfection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A cDNA clone encoding bovine scrapie-associated fibril protein, PrP, from a bovine brain cDNA library and six amplified genomic DNA clones of bovine PrP were characterized. These clones possessed specific characteristics observed in other animal PrP genes. However, the bovine PrP was divided into two types by the number of repeats. One possessed four octapeptide repetitive sequences, like other animal PrP genes, and consisted of 256 amino acids; the other had five such repetitive sequences and 264 amino acids. The amino acid sequence of the former bovine PrP agreed with that of sheep PrP up to the 165th amino acid from the N-terminus. Bovine PrP cDNA introduced into mouse L-929 cells were stably expressed. The expression level of recombinant bovine PrP in the cells judged by immunofluorescence was higher than that of authentic mouse PrP. The recombinant PrP comigrated with authentic bovine PrP in SDS-polyacrylamide gel electrophoresis, suggesting that the recombinant product was fully glycosylated in L-929 cells. Distinct bundles of the intermediate filaments were frequently seen at the perinuclear region of the cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01703083
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  • 4
    Electronic Resource
    Electronic Resource
    Transient expression assay in a baculovirus system using firefly luciferase gene as a reporter (1992)
    Springer
    Virus genes 6 (1992), S. 379-386 
    Details
    ISSN: 1572-994X
    Keywords: recombinant DNA ; gene expression ; polyhedrin gene promoter ; expression vector ; DNA sequencing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Transient gene expression assays were developed to assess the function of the regulatory sequences of baculovirusesBombyx mori nuclear polyhedrosis virus (BmNPV) andAutographa californica nuclear polyhedrosis virus (AcNPV) in insect cells ofBombyx mori andSpodoptera frugiperda, respectively. DNA sequences encoding luciferase (luc) of the fireflyPhotinus pyralis was successfully employed in the expression assay as a reporter gene. Recombinant plasmids were constructed containing the luc gene under control of baculovirus-specific or heterologous promoters. Cotransfection ofBombyx mori andSpodoptera frugiperda cells with recombinant plasmids carrying virus-specific promoter sequences and BmNPV and AcNPV DNA, respectively, gave rise to efficient synthesis of luciferase (Luc), while heterologous promoters induced a low level of luc expression. We found that flanking sequences of the AcNPV DNA in the transfer plasmid contained an unknown promoter conferring an efficient luc expression. The activity of this promoter was modulated by the polh promoter sequences. The assay allows one to conduct highly sensitive monitoring of the transient expression of foreign genes from the transfecting plasmids prior to construction of recombinant viruses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01703086
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  • 5
    Electronic Resource
    Electronic Resource
    Molecular events at nematode-induced feeding sites (1992)
    Springer
    European journal of plant pathology 98 (1992), S. 175-181 
    Details
    ISSN: 1573-8469
    Keywords: Nematodes ; Globodera ; plant pathogen ; infection ; monoclonal antibodies ; PCR ; cDNA libraries ; gene expression ; modified plant cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Current control of nematodes is inadequate and this justifies work towards the design of novel bases for plant defence. Our approach for cyst nematodes began by improving understanding of critical events in the establishment of these biotrophic pathogens. The first step involved development of an experimental system for achieving synchronous infection and establishment of cyst-nematodes in roots. Monoclonal antibodies have been raised against these nematodes, their specificity defined and those of particular interest used to define events in the establishment of the animals within plants. A similar approach has been explored for host responses using antibodies raised to plant tissue containing feeding sites. Changes in translatable mRNA populations at the feeding site have been described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01974484
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  • 6
    Electronic Resource
    Electronic Resource
    Molecular cloning, nucleotide sequence and expression of a cDNA encoding an intracellular protein tyrosine phosphatase, PTPase-2, from mouse testis and T-cells (1992)
    Springer
    Molecular and cellular biochemistry 118 (1992), S. 91-98 
    Details
    ISSN: 1573-4919
    Keywords: mouse ; protein tyrosine phosphatase ; cDNA cloning ; nucleotide sequence ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The PTP-2 cDNA encoding an intracellular protein tyrosine phosphatase (PTPase-2) was isolated and sequenced from mouse testis and T-cell cDNA libraries. This PTP-2 cDNA was found to be homologous to human PTP-TC and rat PTP-S, and contained 1,551 nucleotides, including 1,146 nucleotides encoding 382 amino acids as well as 5′ (61 nucleotides) and 3′ (344 nucleotides) non-coding regions. Northern blot analysis indicated that PTP-2 mRNA of 1.9 Kb was most abundant in testis and kidney, although it was also present in spleen, muscle, liver, heart and brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249698
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  • 7
    Electronic Resource
    Electronic Resource
    Active cell death in hormone-dependent tissues (1992)
    Springer
    Cancer and metastasis reviews 11 (1992), S. 197-220 
    Details
    ISSN: 1573-7233
    Keywords: apotosis ; prostate ; breast ; hormones ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Active cell death (ACD) in hormone-dependent tissues such as the prostate and mammary gland is readily induced by hormone ablation and by treatment with anti-androgens or anti-estrogens, calcium channel agonists and TGFβ. These agents induce a variety of genes within the hormone-dependent epithelial cells including TRPM-2, transglutaminase, poly(ADP-ribose) polymerase, Hsp27 and several other unidentified genes. Not all epithelial cells in the glands are equally sensitive to the induction of ACD. In the prostate, the secretory epithelial cells that are sensitive to hormone ablation are localized in the distal region of the prostatic ducts, and are in direct contact with the neighboring stroma. In contrast, the epithelial cells in the proximal regions of the ducts are more resistant to hormone ablation, probably because the permissive effects of the stroma are attenuated by the presence of the basal epithelial cells, which are intercalated between the epithelium and stroma. The underlying biology of ACD in prostate and mamary glands, and its relevance to hormone resistance, is discussed in this review.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048064
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  • 8
    Electronic Resource
    Electronic Resource
    Genetic approaches to the study of mitochondrial biogenesis in yeast (1992)
    Springer
    Antonie van Leeuwenhoek 62 (1992), S. 131-153 
    Details
    ISSN: 1572-9699
    Keywords: mitochondrial DNA ; mutational analysis ; nucleo-mitochondrial interactions ; gene expression ; membrane assembly ; respiratory deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In contrast to most other organisms, the yeastSaccharomyces cerevisiae can survive without functional mitochondria. This ability has been exploited in genetic approaches to the study of mitochondrial biogenesis. In the last two decades, mitochondrial genetics have made major contributions to the identification of genes on the mitochondrial genome, the mapping of these genes and the establishment of structure-function relationships in the products they encode. In parallel, more than 200 complementation groups, corresponding to as many nuclear genes necessary for mitochondrial function or biogenesis have been described. Many of the latter are required for post-transcriptional events in mitochondrial gene expression, including the processing of mitochondrial pre-RNAs, the translation of mitochondrial mRNAs, or the assembly of mitochondrial translation products into the membrane. The aim of this review is to describe the genetic approaches used to unravel the intricacies of mitochondrial biogenesis and to summarize recent insights gained from their application.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00584467
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  • 9
    Electronic Resource
    Electronic Resource
    The environment, microbes and bioremediation: microbial activities modulated by the environment (1992)
    Springer
    Biodegradation 3 (1992), S. 125-135 
    Details
    ISSN: 1572-9729
    Keywords: natural evolution ; directed evolution ; biodegradation ; environmental pollutants ; environmental signal transduction ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Microorganisms in nature are largely responsible for the biodegradation and removal of toxic and non-toxic chemicals. Many organisms are also known to have specific ecological niches for proliferation and colonization. The nature of the environment dictates to a large extent the biodegradability of synthetic compounds by modulating the evolutionary processes in microorganisms for new degradative genes. Similarly, environmental factors often determine the extent of microbial gene expression by activating or repressing specific gene or sets of genes through a sensory signal transduction process. Understanding how the environment modulates microbial activity is critical for successful bioremediative applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00129078
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  • 10
    Electronic Resource
    Electronic Resource
    Biotechnology in the degradation and utilization of lignocellulose (1992)
    Springer
    Biodegradation 3 (1992), S. 219-238 
    Details
    ISSN: 1572-9729
    Keywords: cellulase ; gene expression ; lignin ; Phanerochaete chrysosporium ; Streptomyces cyaneus ; xylanase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Lignocellulose is the predominant renewable resource. It uses include fuel, as the feedstock for the pulp and paper industry, and for animal nutrition. It also constitutes a large proportion of agricultural and urban waste. Biotechnology has roles in its efficient production and utilisation. The types of lignin substrates available for study of lignin biodegradation are described. The white rot fungus Phanerochaete chrysosporium is the archetypal system for the study of lignocellulose degradation, since it mineralises lignin and degrades both cellulose and hemicellulose. The salient features of the P. chrysosporium system are described. The lignin peroxidases are a family of proteins, and it is shown that expression of their genes is differential. P. chrysosporium is heterokaryotic with two gene equivalents that have abundant RFLPs. A set of basidiospore-derived strains with genetic compositions defined by such RFLPs provided the potential basis for a strain improvement programme for lignin degradation. However, analysis of this system using radiolabelled synthetic lignin (DHP) as the substrate confirmed previous evidence that both the substrate and the fungal cultures displayed much variation, so that it was difficult to quantify performance for this property. The cellobiohydrolase I enzymes are also coded for by a family of genes, and evidence is also presented for allelic variants, for differential expression and for differential splicing. In contrast, the cellobiohydrolase II function is encoded at a unique genetic locus. Approaches to an homologous integrative transformation system are discussed. Some actinomycete bacteria represent an alternative system for lignin solubilisation in which strains differ in their spectra of activities on lignocellulose substrates. The xylanase system of Streptomyces cyaneus is shown to include three enzymes, two of which are inducible by xylan. A novel assay method was developed and used to demonstrate that the third is constitutive and also non-repressible by glucose. It is proposed that this acts as a sensor for xylans in the environment that can yield breakdown products that are taken up and can then act as inducers of the other two enzymes. The studies on microbial lignocellulose degradation from different laboratories have allowed the formulation of specific biotechnological goals, and some of the problems and opportunities in this area are identified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00129085
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  • 11
    Electronic Resource
    Electronic Resource
    Peroxisome biogenesis inSaccharomyces cerevisiae (1992)
    Springer
    Antonie van Leeuwenhoek 62 (1992), S. 63-78 
    Details
    ISSN: 1572-9699
    Keywords: biogenesis ; gene expression ; mutants ; peroxisomes ; yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The observation that peroxisomes ofSaccharomyces cerevisiae can be induced by oleic acid has opened the possibility to investigate the biogenesis of these organelles in a biochemically and genetically well characterized organism. Only few enzymes have been identified as peroxisomal proteins inSaccharomyces cerevisiae so far; the three enzymes involved in β-oxidation of fatty acids, enzymes of the glyoxylate cycle, catalase A and the PAS3 gene product have been unequivocally assigned to the peroxisomal compartment. However, more proteins are expected to be constituents of the peroxisomes inSaccharomyces cerevisiae. Mutagenesis ofSaccharomyces cerevisiae cells gave rise to mutants unable to use oleic acid as sole carbon source. These mutants could be divided in two groups: those with defects in structural genes of β-oxidation enzymes (fox-mutants) and those with defects in peroxisomal assembly (pas-mutants). All fox-mutants possess morphologically normal peroxisomes and can be assigned to one of three complementation groups (FOX1, 2, 3). All three FOX genes have been cloned and characterized. The pas-mutants isolated are distributed among 13 complementation groups and represent 3 different classes: peroxisomes are either morphologically not detectable (type I) or present but non-proliferating (type II). Mislocalization concerns all peroxisomal proteins in cells of these two classes. The third class of mutants contains peroxisomes normal in size and number, however, distinct peroxisomal matrix proteins are mislocalized (type III). Five additional complementation groups were found in the laboratory of H.F. Tabak. Not all PAS genes have been cloned and characterized so far, and only for few of them the function could be deduced from sequence comparisons. Proliferation of microbodies is repressed by glucose, derepressed by non-fermentable carbon sources and fully induced by oleic acid. The regulation of four genes encoding peroxisomal proteins (PAS1, CTA1, FOX2, FOX3) occurs on the transcriptional level and reflects the morphological observations: repression by glucose and induction by oleic acid. Moreover, trans-acting factors like ADR1, SNF1 and SNF4, all involved in derepression of various cellular processes, have been demonstrated to affect transcriptional regulation of genes encoding peroxisomal proteins. The peroxisomal import machinery seems to be conserved between different organisms as indicated by import of heterologous proteins into microbodies of different host cells. In addition, many peroxisomal proteins contain C-terminal targeting signals. However, more than one import route into peroxisomes does exist. Dissection of the import mechanism in a genetically well suited organism likeSaccharomyces cerevisiae together with further characterization and functional assignment of the PAS gene products will provide insight into the biogenesis of peroxisomes. Moreover, these studies will lead to a good model system for elucidation of the mechanisms underlying human peroxisomal disorders.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00584463
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  • 12
    Electronic Resource
    Electronic Resource
    Phosphoribulokinase from ice plant: Transcription, transcripts and protein expression during environmental stress (1992)
    Springer
    Photosynthesis research 31 (1992), S. 127-138 
    Details
    ISSN: 1573-5079
    Keywords: environmental stress ; Mesembryanthemum crystallinum ; phosphoribulokinase ; gene expression ; protein expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The expression of PRK (phosphoribulokinase, E.C.2.7.1.19) in ice plant (Mesembryanthemum crystallinum) during development and under environmental stress was studied. cDNA clones were isolated and full-length cDNAs were characterized. Ice plant PRK is contained in a 1520 nucleotide transcript including a 126 nucleotide leader sequence, a 175 nucleotide 3′-end and a 20–30 nucleotide polyA+-stretch. The coding region, 397 codons, specifies a protein of Mr 44 064. The mature sequence is preceded by a transit peptide of approximately 46 amino acids. The mature portion of ice plant PRK is 86.4% identical to that of spinach and, e.g., 16.2% identical to PRK from Xanthomonas flavus. Under salt stress or cold adaptation conditions, the amount of mRNA declined by a factor of approximately three within days, followed by an increase to approximately pre-stress levels. The fluctuation in mRNA amount is not reflected on the level of transcription of the gene, suggesting post-transcriptional control, nor is PRK protein amount affected significantly over the short stress period. The recovery of transcript levels for photosynthesis-related proteins after stress appears to be a general response to environmental stresses that affect water status in ice plant. We suggest that the photosynthetic machinery in this facultative halophyte is effectively buffered from damage caused by such environmental stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028789
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  • 13
    Electronic Resource
    Electronic Resource
    Respiratory metabolism and gene expression during seed germination (1992)
    Springer
    Plant growth regulation 11 (1992), S. 211-224 
    Details
    ISSN: 1573-5087
    Keywords: Germination ; energy metabolism ; gene expression ; regulation ; respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Oxygen uptake and carbon dioxide release rapidly increase in seeds during imbibition. The oxygen uptake is associated with oxidative phosphorylation through cytochrome oxidase. During the early stage of germination substrate level phosphorylation may also contribute to ATP production. All indications suggest that this route of ATP production is insignificant during aerobic germination. However, during oxygen stress, substrate level phosphorylation does significantly contribute to ATP production in some species. Carbohydrate oxidation plays a significant role in the germination process. Up to two thirds of the carbon from carbohydrate breakdown enters the tricarboxylic acid cycle through the phosphoenolpyruvate carboxylase reaction. This anapleurotic input into the Krebs cycle most probably reflects the high demand on intermediates from the cycle for biosynthesis. The extent to which other substrates are utilized for respiration is uncertain. Information regarding the levels of key metabolites and enzymes, as well as their cellular distribution is limited. The involvement of gene expression in the regulation of respiratory metabolism is poorly characterised. Several genes which have been cloned are only expressed during germination. With the exception of the early methionine labeled polypeptide, little is known about the function of these genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024560
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  • 14
    Electronic Resource
    Electronic Resource
    Effect of deletions 5′ to the translation initiation sequence on the expression of an mRNA in animal cells (1992)
    Springer
    Molecular biology reports 16 (1992), S. 277-284 
    Details
    ISSN: 1573-4978
    Keywords: translational initiation ; 18S rRNA ; mRNA secondary structure ; gene expression ; initiation mutants ; β-galactosidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To learn if an mRNA·18S rRNA interaction or a special secondary structure in the mRNA start region is essential for translation in eukaryotic cells, we constructed recombinant plasmids with the SV40 early promoter 5′ to part of the Escherichia coli tuf B-lacZ gene. Deletion of bases potentially complementary to the 18S rRNA highly increased the transient β-galactosidase expressed in transfected CHO cells. Deletion of bases that fostered formation of potential hairpins with the mRNA 5′-terminus or altered the structure of the coding region reduced β-galactosidase activity suggesting that these features of the mRNA secondary structure may be essential for initiation of translation. Computer aided analysis of the potential structure of 290 mRNAs suggests these are conserved features of the initiation region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00419668
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  • 15
    Electronic Resource
    Electronic Resource
    The early genetic response to light in the green unicellular alga Chlamydomonas eugametos grown under light/dark cycles involves genes that represent direct responses to light and photosynthesis (1992)
    Springer
    Plant molecular biology 18 (1992), S. 429-445 
    Details
    ISSN: 1573-5028
    Keywords: Chlamydomonas eugametos ; chlorophyll a/b-binding proteins ; circadian oscillator ; gene expression ; light-regulated genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the green unicellular alga Chlamydomonas eugametos, cellular division is readily synchronized by light/dark cycles. Under these conditions, light initiates photosynthetic growth in daughter cells and begins the G1 phase. Genes whose expression is regulated upon illumination are likely to be important mechanisms controlling cell proliferation. To identify some of those genes, two cDNA libraries were prepared with poly(A)+ extracted from cells either stimulated with light for 1 h or held in darkness (quiescent cells) during the same period. To restrict our analysis to those genes that are part of the primary response, cells were incubated in presence of cycloheximide. Differential screening of approximately 40 000 clones in each library revealed 44 clones which hybridize preferentially with a [32P] cDNA probe derived from RNA of light-stimulated cells and 15 clones which react selectively with a [32P] cDNA probe synthesized from poly(A)+ RNA of quiescent cells. Cross-hybridization of these clones identified 4 independent sequences in the light-induced (LI) collection and 2 in the uninduced (LR) library. Four of these cDNAs correspond to mRNAs that are positively or negatively regulated upon activation of photosynthesis. One clone represents a mRNA that accumulates transitorily at both transitions. Finally, LI818 cDNA identifies a new chlorophyll a/b-binding (cab) gene family whose mRNA accumulation is controlled by light and a circadian oscillator. The endogenous timing system controls LI818 mRNA accumulation so that it precedes the onset of illumination by a few hours. On the other hand, light affects LI818 mRNA levels independently of active photosynthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040659
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  • 16
    Electronic Resource
    Electronic Resource
    Salt-inducible betaine aldehyde dehydrogenase from sugar beet: cDNA cloning and expression (1992)
    Springer
    Plant molecular biology 18 (1992), S. 1-11 
    Details
    ISSN: 1573-5028
    Keywords: betaine aldehyde dehydrogenase ; gene expression ; glycine betaine ; osmotic stress ; salt tolerance ; sugar beet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Members of the Chenopodiaceae, such as sugar beet and spinach, accumulate glycine betaine in response to salinity or drought stress. The last enzyme in the glycine betaine biosynthetic pathway is betaine aldehyde dehydrogenase (BADH). In sugar beet the activity of BADH was found to increase two- to four-fold in both leaves and roots as the NaCl level in the irrigation solution was raised from 0 to 500 mM. This increase in BADH activity was paralleled by an increase in level of translatable BADH mRNA. Several cDNAs encoding BADH were cloned from a λgt10 libary representing poly(A)+ RNA from salinized leaves of sugar beet plants, by hybridization with a spinach BADH cDNA. Three nearly full-length cDNA clones were confirmed to encode BADH by their nucleotide and deduced amino acid sequence identity to spinach BADH; these clones showed minor nucleotide sequence differences consistent with their being of two different BADH alleles. The clones averaged 1.7 kb and contained an open reading frame predicting a polypeptide of 500 amino acids with 83% identity to spinach BADH. RNA gel blot analysis of total RNA showed that salinization to 500 mM NaCl increased BADH mRNA levels four-fold in leaves and three-fold in the taproot. DNA gel blot analyses indicated the presence of at least two copies of BADH in the haploid sugar beet genome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00018451
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  • 17
    Electronic Resource
    Electronic Resource
    Developmental and environmental concurrent expression of sunflower dry-seed-stored low-molecular-weight heat-shock protein and Lea mRNAs (1992)
    Springer
    Plant molecular biology 19 (1992), S. 781-792 
    Details
    ISSN: 1573-5028
    Keywords: sunflower ; gene expression ; zygotic embryogenesis ; Lea proteins ; heat-shock proteins ; abscisic acid ; osmotic stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have cloned and sequenced three different cDNAs from sunflower seed-stored mRNA. Sequence similarities and response to heat-shock identified one of the cDNAs as a low-molecular-weight heat-shock protein (lmw-HSP). The other two clones showed significant sequence similarity to the cotton and carrot late-embryogenesis-abundant (Lea) proteins D-113 and Emb-1, respectively. The three cDNAs showed similar expression patterns during zygotic embryo development, as well as in vegetative tissues of 3-day-old seedlings in response to stress. Maximal accumulation of all three mRNAs was detected in dry seeds and during embryo mid-maturation stage, in the absence of exogenous stress. In seedlings, mRNAs accumulated to lower levels in response to osmotic stress and exogenous abscisic acid (ABA) treatments. A differential time course of response to osmotic stress was observed: lmw-HSP mRNA accumulation was induced earlier than that of Lea mRNAs. The coordinate accumulation of Lea and lmw-HSP transcripts during embryo development and in response to stress and ABA suggests the existence of common regulatory elements for Lea and lmw-HSP genes, and supports the notion that HSPs might have alternative functions in the plant cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027074
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  • 18
    Electronic Resource
    Electronic Resource
    Molecular cloning and expression of the gene encoding ADP-glucose pyrophosphorylase from the cyanobacteriumAnabaena sp. strain PCC 7120 (1992)
    Springer
    Plant molecular biology 20 (1992), S. 37-47 
    Details
    ISSN: 1573-5028
    Keywords: ADP-glucose pyrophosphorylase ; Anabaena 7120 ; Escherichia coli ; gene cloning ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous studies have indicated that ADP-glucose pyrophosphorylase (ADPGlc PPase) from the cyanobacteriumAnabaena sp. strain PCC 7120 is more similar to higher-plant than to enteric bacterial enzymes in antigenicity and allosteric properties. In this paper, we report the isolation of theAnabaena ADPGlc PPase gene and its expression inEscherichia coli. The gene we isolated from a genomic library utilizes GTG as the start codon and codes for a protein of 48347 Da which is in agreement with the molecular mass determined by SDS-PAGE for theAnabaena enzyme. The deduced amino acid sequence is 63, 54, and 33% identical to the rice endosperm small subunit, maize endosperm large subunit, and theE. coli sequences, respectively. Southern analysis indicated that there is only one copy of this gene in theAnabaena genome. The cloned gene encodes an active ADPGlc PPase when expressed in anE. coli mutant strain AC70R1-504 which lacks endogenous activity of the enzyme. The recombinant enzyme is activated and inhibited primarily by 3-phosphoglycerate and Pi, respectively, as is the nativeAnabaena ADPGlc PPase. Immunological and other biochemical studies further confirmed the recombinant enzyme to be theAnabaena enzyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029147
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  • 19
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    Electronic Resource
    Nucleotide sequence and temporal regulation of a seed-specificBrassica napus cDNA encoding a stearoyl-acyl carrier protein (ACP) desaturase (1992)
    Springer
    Plant molecular biology 20 (1992), S. 151-155 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; desaturation ; oil synthesis ; embryogenesis ; stearoyl-acyl carrier protein desaturase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nucleotide sequence is reported for a cDNA containing the entire coding region of a stearoyl-ACP desaturase (EC 1.14.99.6) fromBrassica napus L. cv. Jet neuf. The cDNA was obtained from a library constructed from poly(A)+ RNA purified from embryo tissue. The derived amino acid sequence demonstrates substantial similarity with those from other plant Δ9-desaturases. Comparative RNA-dot blot analyses using the Δ9-desaturase cDNA and a rapessed oleosin cDNA as probes showed that although both these transcripts were seed-specific, they exhibited distinct patterns of temporal regulation. The desaturase message was induced by 25 days after anthesis (DAA), peaking at 45 DAA but decreasing considerably thereafter. In contrast, the oleosin transcript did not increase until 45–50 DAA, reaching a peak much later at about 70 DAA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029157
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  • 20
    Electronic Resource
    Electronic Resource
    Differential accumulation of mRNAs encoding extracellular and intracellular PR proteins in tomato induced by virulent and avirulent races of Cladosporium fulvum (1992)
    Springer
    Plant molecular biology 20 (1992), S. 513-527 
    Details
    ISSN: 1573-5028
    Keywords: β-1,3-glucanase ; gene expression ; pathogenesis-related proteins ; plant-fungus interaction ; protein P14
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tomato leaves infected by the fungal pathogen Cladosporium fulvum contain several types of intracellular and extracellular pathogenesis-related (PR) proteins. Previously, we reported the purification and serological characterization of five extracellular PR proteins: P2, P4, P6, a chitinase and a β-1,3-glucanase [22, 23]. Here we describe the purification of a basic intracellular 33 kDa β-1,3-glucanase and the isolation and characterization of cDNA clones encoding the two extracellular P14 isomers P4 and P6, the extracellular acidic β-1,3-glucanase and a basic 35 kDa β-1,3-glucanase, different from the purified 33 kDa protein. Southern blot analysis demonstrated that tomato PR proteins are not encoded by large gene families, as is the case in tobacco. The number of genes corresponding to each protein was estimated to vary between one and three. A northern blot analysis indicated that the mRNAs for the extracellular PR proteins (P4, P6 and acidic β-1,3-glucanase) accumulate to similar levels in compatible and incompatible tomato-C. fulvum interactions, although the maximum level of expression is reached much faster in the incompatible interaction. On the other hand, the mRNA for the basic 35 kDa β-1,3-glucanase is induced rapidly to high levels in both interactions, but declines in time to background levels only in the incompatible interaction. The relevance of this difference in relation to plant defence is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040610
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  • 21
    Electronic Resource
    Electronic Resource
    Expression and sequence analysis of cDNAs induced during the early stages of tuberisation in different organs of the potato plant (Solanum tuberosum L.) (1992)
    Springer
    Plant molecular biology 20 (1992), S. 641-651 
    Details
    ISSN: 1573-5028
    Keywords: S-adenosylmethionine decarboxylase ; differential screening ; gene expression ; Solanum tuberosum ; tuberisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract cDNA clones of two genes (TUB8 and TUB13) which show a 25–30-fold increase in transcript in the stolon tip during the early stages of tuberisation, have been isolated by differential screening. These genes are also expressed in leaves, stems and roots and the expression pattern in these organs changes on tuberisation. Southern analysis shows homologous sequences in the non-tuberising wild type potato species Solanum brevidens and in Lycopersicon esculentum (tomato). Sequence analysis reveals a high degree of similarity between the TUB13 cDNA, and a human S-adenosylmethionine decarboxylase gene. The predicted TUB8 peptide sequence shows several repeats of alanine, glutamate and proline which suggests a structural role for the encoded protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046449
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  • 22
    Electronic Resource
    Electronic Resource
    Structure and expression of a sugarcane gene encoding a housekeeping phosphoenolpyruvate carboxylase (1992)
    Springer
    Plant molecular biology 20 (1992), S. 663-671 
    Details
    ISSN: 1573-5028
    Keywords: PEP carboxylase ; housekeeping gene ; gene expression ; gene structure ; light-mediated activation ; Saccharum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A gene (SCPEPCD1) encoding phosphoenolpyruvate carboxylase (PEPC) was isolated from the C-4 monocot sugarcane (Saccharum hybrid var. H32-8560). SCPEPCD1 is ca. 6800 bp long, with 10 exons. The entire gene sequence from −1561 to 262 bp downstream of the putative poly(A) addition signal is reported. A low-level, essentially constitutive pattern of expression, amino acid sequence similarities to other ‘housekeeping’ PEPC enzymes, and the absence of DNA sequence elements conserved in the upstream region of maize and sorghum C-4-specific PEPC genes indicate that SCPEPCD1 encodes a housekeeping PEPC. Despite this, a motif proposed to act as a phosphorylation site in light-mediated activation of photosynthetic PEPC enzymes [10] is present in the SCPEPCD1 protein; evidence is presented for the presence of this site in other housekeeping PEPC proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046451
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  • 23
    Electronic Resource
    Electronic Resource
    Molecular cloning of an alanine aminotransferase from NAD-malic enzyme type C4 plant Panicum miliaceum (1992)
    Springer
    Plant molecular biology 20 (1992), S. 705-713 
    Details
    ISSN: 1573-5028
    Keywords: alanine aminotransferase ; C4 photosynthesis ; gene expression ; nucleotide sequencing ; Panicum miliaceum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have determined the nucleotide sequence of a cDNA encoding AlaAT-2, which is believed to function in the C4-pathway of Panicum miliaceum. An open reading frame (1446 bp) encodes a protein of 482 amino acid residues. The deduced amino acid sequence of AlaAT-2 shows 44.2 and 44.8% homology with the amino acid sequences of AlaATs from rat and human livers, respectively. Northern blot analysis showed that the gene encoding AlaAT-2 in mesophyll and bundle sheath cells was the same and transcribed similarly in the cells. The level of translatable mRNA for AlaAT-2 increased dramatically during greening.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046455
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  • 24
    Electronic Resource
    Electronic Resource
    Dynamical behavior of psb gene transcripts in greening wheat seedlings. I. Time course of accumulation of the psbA through psbN gene transcripts during light-induced greening (1992)
    Springer
    Plant molecular biology 20 (1992), S. 695-704 
    Details
    ISSN: 1573-5028
    Keywords: chloroplast ; gene expression ; photosystem 2 ; transcription ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The time course of the accumulation of the transcripts from 13 psb genes encoding a major part of the proteins composing photosystem II during light-induced greening of dark-grown wheat seedlings was examined focusing on early stages of plastid development (0.5 h through 72 h). The 13 genes can be divided into three groups. (1) The psbA gene is transcribed as a single transcript of 1.3 kb in the dark-grown seedlings, but its level increases 5- to 7-fold in response to light due to selective increase in RNA stability as well as in transcription activity. (2) The psbE-F-L-J operon, psbM and psbN genes are transcribed as a single transcript of 1.1 kb, two transcripts of 0.5 and 0.7 kb and a single transcript of 0.3 kb, respectively, in the dark-grown seedlings. The levels of accumulation of every transcript remain unchanged or rather decrease during plastid development under illumination. (3) The psbK-I-D-C gene cluster and psbB-H operon exhibit fairly complicated northern hybridization patterns during the greening process. When a psbC or psbD gene probe was used for northern hybridization, five transcripts differing in length were detected in the etioplasts from 5-day old dark-grown seedlings. After 2 h illumination, two new transcripts of different length appeared. Light induction of new transcripts was also observed in the psbB-H operon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046454
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  • 25
    Electronic Resource
    Electronic Resource
    Effect of salt stress on plant gene expression: A review (1992)
    Springer
    Plant and soil 146 (1992), S. 145-151 
    Details
    ISSN: 1573-5036
    Keywords: barley ; gene expression ; ice plant ; rice ; salt stress ; tobacco ; tomato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soil salinity is an important agricultural problem, particularly since the majority of crop plants have low salt tolerance. The identification of genes whose expression enables plants to adapt to or tolerate salt stress is essential for breeding programs, but little is known about the genetic mechanisms for salt tolerance. Recent research demonstrates that salt stress modulates the levels of a number of gene products. Although the detection of gene products that respons specifically to salt stress is a significant finding, they must be identified, functions assigned, and their relation to salt tolerance determined. This article focuses on a few of the salt-responsive proteins and mRNAs that have been discovered and the methods employed to identify and characterize them.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00012007
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  • 26
    Electronic Resource
    Electronic Resource
    Accumulation of wound-inducible ACC synthase transcript in tomato fruit is inhibited by salicylic acid and polyamines (1992)
    Springer
    Plant molecular biology 18 (1992), S. 477-487 
    Details
    ISSN: 1573-5028
    Keywords: Tomato ; gene expression ; wounding ; ethylene ; glycine-rich protein ; rRNA ; polyamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Regulation of wound-inducible 1-aminocyclopropane-1-carboxylic acid (ACC) synthase expression was studied in tomato fruit (Lycopersicon esculentum cv. Pik-Red). A 70 base oligonucleotide probe homologous to published ACC synthase cDNA sequences was successfully used to identify and analyze regulation of a wound-inducible transcript. The 1.8 kb ACC synthase transcript increased upon wounding the fruit as well as during fruit ripening. Salicylic acid, an inhibitor of wound-responsive genes in tomato, inhibited the wound-induced accumulation of the ACC synthase transcript. Further, polyamines (putrescine, spermidine and spermine) that have anti-senescence properties and have been shown to inhibit the development of ACC synthase activity, inhibited the accumulation of the wound-inducible ACC synthase transcript. The inhibition by spermine was greater than that caused by putrescine or spermidine. The transcript level of a wound-repressible glycine-rich protein gene and that of the constitutively expressed rRNA were not affected as markedly by either salicylic acid or polyamines. These data suggest that salicylic acid and polyamines may specifically regulate ethylene biosynthesis at the level of ACC synthase transcript accumulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040664
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  • 27
    Electronic Resource
    Electronic Resource
    Effect of two consensus sequences preceding the translation initiator codon on gene expression in plant protoplasts (1992)
    Springer
    Plant molecular biology 18 (1992), S. 815-818 
    Details
    ISSN: 1573-5028
    Keywords: expression cassette ; gene expression ; protoplasts ; translation initiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Expression cassettes containing a duplicated cauliflower mosaic virus (CaMV) 35S promoter fused to a polylinker preceded by the CCACCATGG and AACAATGG sequences were constructed. These two sequences correspond to the consensus sequences around the translation start codons in vertebrates and plants respectively. Translational fusions were made with the β-glucuronidase-coding sequence and transient expression was recorded in tobacco mesophyll protoplasts. Approximately three times more GUS activity was found in protoplasts incubated with the constructs harbouring translational fusions as compared to a control harbouring a transcriptional fusion. No significant difference was observed between GUS activities obtained with the two consensus sequences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00020027
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  • 28
    Electronic Resource
    Electronic Resource
    Structure of a rice β-glucanase gene regulated by ethylene, cytokinin, wounding, salicylic acid and fungal elicitors (1992)
    Springer
    Plant molecular biology 18 (1992), S. 33-45 
    Details
    ISSN: 1573-5028
    Keywords: glucanase ; gene expression ; pathogenesis response ; stress response ; plant growth regulators ; gene family
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A rice β-glucanase gene was sequenced and its expression analyzed at the level of mRNA accumulation. This gene (Gns1) is expressed at relatively low levels in germinating seeds, shoots, leaves, panicles and callus, but it is expressed at higher levels in roots. Expression in the roots appears to be constitutive. Shoots expressGns1 at much higher levels when treated with ethylene, cytokinin, salicylic acid, and fungal elicitors derived from the pathogenSclerotium oryzae or from the non-pathogenSaccharomyces cereviseae. Shoots also expressGns1 at higher levels in response to wounding. Expression in the shoots is not significantly affected by auxin, gibberellic acid or abscisic acid. The β-glucanase shows 82% amino acid similarity to the barley 1,3;1,4-β-D-glucanases, and from hybridization studies it is the β-glucanase gene in the rice genome closest to the barley 1,3;1,4-β-glucanase EI gene. The mature peptide has a calculated molecular mass of 32 kDa. The gene has a large 3145 bp intron in the codon for the 25th amino acid of the signal peptide. The gene exhibits a very strong codon bias of 99% G+C in the third position of the codon in the mature peptide coding region, but only 61% G+C in the signal peptide region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00018454
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  • 29
    Electronic Resource
    Electronic Resource
    Characterization and expression of U1snRNA genes from potato (1992)
    Springer
    Plant molecular biology 19 (1992), S. 959-971 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; gene variants ; pre-mRNA splicing ; pseudogenes ; U1 small nuclear RNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract U1 small nuclear RNAs (U1snRNAs) occur in the nucleus of plants and animals where, complexed with several proteins in the form of U1 small nuclear ribonucleoprotein particles (U1snRNPs), they play an important role in precursor messenger RNA (pre-mRNA) splicing. Ten potato U1snRNA genes have been isolated on two genomic clones illustrating the clustering of this multigene family on the potato genome. Based on both the sequence of their coding regions and upstream regulatory elements, seven of the genes are potentially functional. The other three genes were pseudogenes with defective promoter or coding region sequences. Analysis of expression of individual cloned U1snRNA genes in transfected tobacco protoplasts was impossible due to the similarity of U1snRNA sequences in tobacco. However, by marking the coding regions with oligonucleotides or constructing chimaeric genes consisting of a potato U1snRNA promoter region and maize U5snRNA coding region, three of the U1 promoter regions were shown to be transcriptionally active.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040528
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  • 30
    Electronic Resource
    Electronic Resource
    Characterization of the U3 and U6 snRNA genes from wheat: U3 snRNA genes in monocot plants are transcribed by RNa polymerase III (1992)
    Springer
    Plant molecular biology 19 (1992), S. 973-983 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; promoter specificity ; snRNA gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have demonstrated recently that the genes encoding the U3 small nuclear RNA (snRNA) in dicot plants are transcribed by RNA polymerase III (pol III), and not RNA polymerase II (pol II) as in all other organisms studied to date. The U3 gene was the first example of a gene transcribed by different polymerases in different organisms. Based on phylogenetic arguments we proposed that a polymerase specificity change of the U3 snRNA gene promoter occurred during plant evolution. To map such an event we are examining the U3 gene polymerase specificity in other plant species. We report here the characterization of a U3 gene from wheat, a monocot plant. This gene contains the conserved promoter elements, USE and TATA, in a pol III-specific spacing seen also in a wheat U6 snRNA gene characterized in this report. Both the U3 and the U6 genes possess typical pol III termination signals but lack the cis element, responsible for 3′-end formation, found in all plant pol II-specific snRNA genes. In addition, expression of the U3 gene in transfected maize protoplasts is less sensitive to α-amanitin than a pol II-transcribed U2 gene. Based on these data we conclude that the wheat U3 gene is transcribed by pol III. This observation suggests that the postulated RNA polymerase specificity switch of the U3 gene took place prior to the divergence of angiosperm plants into monocots and dicots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040529
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  • 31
    Electronic Resource
    Electronic Resource
    Molecular analysis of a cruciferin storage protein gene family of Brassica napus (1992)
    Springer
    Plant molecular biology 19 (1992), S. 1049-1055 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; rapeseed ; gene expression ; nucleotide sequence ; storage proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated a five-member gene subfamily which encodes cruciferin, a legumin-like 12S storage protein of Brassica napus L., and have analyzed the structure and expression of the family members in developing embryos. Sequence analysis has shown that the coding regions of all five genes are highly similar, with the two most divergent members of the family retaining 89% sequence identity. The analysis of this cruciferin gene family's expression indicates that the developmental pattern of expression of each gene is similar, and the steady-state mRNA levels of each gene are approximately equivalent to each other at all developmental stages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040536
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  • 32
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    Electronic Resource
    Differential gene expression during germination and after the induction of adventitious bud formation in Norway spruce embryos (1992)
    Springer
    Plant molecular biology 18 (1992), S. 713-724 
    Details
    ISSN: 1573-5028
    Keywords: adventitious buds ; cDNA cloning ; cytokinin ; gene expression ; germination ; Norway spruce
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A pulse treatment of embryos of Norway spruce with cytokinin suppresses germinative development and induces the coordinate formation of adventitious buds from subepidermal cell layers. To analyse the patterns of gene expression associated with germination and the alterations induced by the bud induction treatment, we have isolated cDNA clones corresponding to genes that are differentially expressed in cytokinin-treated and untreatedin vitro germinating embryos. One category of 14 clones hybridized to transcripts that were abundant specifically during germination. The expression of 8 of these genes was reduced by the bud induction treatment. Four clones, including one identified as a histone H2A gene, recognized transcripts that showed an increased abundance in bud-induced versusin vitro germinating embryos. A second category of 13 clones hybridized to transcripts that increased in abundance during post-germinative development of the seedling. Among these a subset of 8 clones, including an α-tubulin clone, corresponds to genes suppressed by the bud induction treatment, whereas 5 clones, including a gene with sequence similarity to polyubiquitin, were unaffected by the treatment. One clone hybridized to a message abundant in the seed, during early germination as well as in the vegetative bud, and showed 60% partial sequence identity to a barley (1→3)-β-glucanase gene. Genes expressed exclusively in bud-induced orin vitro germinating embryos were not found. The results show that a major difference in gene expression between treated and untreated embryos is related to the shift from extensive cell proliferation to elongation and differentiation that occurs at the transition from germination to post-germinative development, and which is suppressed in the bud-induced embryos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00020013
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  • 33
    Electronic Resource
    Electronic Resource
    A probable lipid transfer protein gene is induced by NaCl in stems of tomato plants (1992)
    Springer
    Plant molecular biology 18 (1992), S. 749-757 
    Details
    ISSN: 1573-5028
    Keywords: salt stress ; stem-specific expression ; lipid transfer protein ; cDNA sequence ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A full-length tomato cDNA clone, TSW12, which is developmentally and environmentally regulated, has been isolated and characterized. TSW12 mRNA is accumulated during tomato seed germination and its level increases after NaCl treatment or heat shock. In mature plants, TSW12 mRNA is only detected upon treatment with NaCl, mannitol or ABA and its expression mainly occurs in stems. The nucleotide sequence of TSW12 includes an open reading frame coding for a basic protein of 114 amino acids; the first 23 amino acids exhibit the sequence characteristic of a signal peptide. The high similarity between the TSW12-deduced amino acid sequence and reported lipid transfer proteins suggests that TSW12 encodes a lipid transfer protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00020016
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  • 34
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    Cytoplasmic ribosomal protein S15a from Brassica napus: Molecular cloning and developmental expression in mitotically active tissues (1992)
    Springer
    Plant molecular biology 18 (1992), S. 909-919 
    Details
    ISSN: 1573-5028
    Keywords: ribosomal protein S15a ; cDNA clones ; rapessed ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated two cDNA clones which appear to encode the 40S ribosomal subunit protein S15a from Brassica napus (oilseed rape). The open reading frame in both clones contains 390 bases, encoding a deduced polypeptide sequence of 130 amino acids (100% homology between clones) with 76% sequence identity to the N-terminal 37 amino acids of the rat ribosomal protein S15a and 80% identity to the S24 polypeptide of yeast. Both the yeast and rapeseed proteins have a net positive charge of +9 and the rapeseed S15a protein has a molecular mass of 14778 Da compared to 14762 Da for the yeast protein. The rapeseed ribosomal protein S15a is encoded by a small multi-gene family with at least two actively transcribed members. A single transcript of ca. 1.0 kb, corresponding to ribosomal protein S15a, is abundant in actively dividing tissues such as apical meristem, flower buds and young leaves and less abundant in mature stem and fully expanded leaves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019205
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  • 35
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    Expression of 17 rye (Secale cereale L.) traits in a range of durum wheat (Triticum durum Desf.) and bread wheat (T. aestivum L.) genetic backgrounds (1992)
    Springer
    Euphytica 60 (1992), S. 37-44 
    Details
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; Triticum durum ; bread wheat ; durum wheat Secale cereale ; rye ; gene expression ; alien introduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Expression of 17 rye traits in 24 bread wheat x rye and 8 durum wheat x rye crosses was studied, using a self-compatible, homozygous, dwarf rye. Rye showed epistasis for hairiness on the peduncle in all the crosses of Triticum aestivum and T. durum wheats with rye. Dark greenness of leaves of rye was expressed in all the durum wheat x rye and in some of the bread wheat x rye crosses. Similarly, absence of auricle pubescence, a rye trait, was expressed in most of the durum wheat x rye crosses but not in the bread wheat x rye crosses, indicating the presence of inhibitors for these traits frequently on the D genome and rarely on the A and/or B genome of wheat. Most of the wide hybrids resembled rye fully or partially for intense waxy bloom on the leaf-sheath and for the absence of basal underdeveloped spikelets. Similarly, most of the amphihaploids resembled rye for the anthocyanin in the coleoptile, stem and node. The presence of some inhibitors on A and/or B genome of wheat was indicated in some of the wheat genotypes for the expression of rye traits viz. intense waxy bloom, anthocyanin in node and absence of basal underdeveloped spikelets. Enhancement in the level of expression of the intensity and length of bristles on the mid-rib of the glume of the hybrids might be due to wheat-rye interaction. Less number of florets/spikelet as in rye showed variable expression in different wheat backgrounds. Some other rye traits like absence of auricles, terminal spikelet and glume-awn were not expressed in the wheat background. The expression of some of the rye genes might have been influenced by their interaction with Triticum cytoplasm and/or the environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00022256
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  • 36
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    Electronic Resource
    Isolation and characterization of a cDNA that encodes ECP31, an embryogenic-cell protein from carrot (1992)
    Springer
    Plant molecular biology 19 (1992), S. 239-249 
    Details
    ISSN: 1573-5028
    Keywords: ABA ; Daucus carota ; ECP31 ; gene expression ; LEA clone ; somatic embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A full-length cDNA for ECP31, an embryogenic cell protein from carrot (Daucus carota L.) with a M r of 31000 (Kiyosue T, Satoh S, Kamada H, Harada H (1991) Plant Physiol 95: 1077–1083), was isolated from a cDNA library prepared from embryogenic cells using PCR-amplified DNA as a probe. The genomic Southern blot analysis revealed that there are two or three genes for ECP31 in the carrot genome. The transcripts of ECP31 accumulated in the peripheral regions of clusters of embryogenic cells and disappeared in the course of somatic embryogenesis that was induced by transfer of the embryogenic cells to auxin-free media. The cDNA encodes a polypeptide of 256 amino acids, and the calculated molecular weight of this polypeptide is 26 111. The deduced amino acid sequence shows a high degree (62.2%) of similarity to that of a protein that is abundant during late embryogenesis of cotton (LEA D34; Baker JC, Steele C, Dure III (1988) Plant Mol Biol 11: 227–291). The mRNAs for ECP31 started to accumulate in zygotic embryos at a late stage of embryogenesis but were undetectable in mature embryos within 24 h after imbibition of seeds. In dry fruits (seeds), the transcripts were detected only in zygotic embryos by in situ hybridization. The level of ECP31 transcripts increased after treatment with abscisic acid (ABA) in torpedo-shaped somatic embryos but not in seven-day-old seedlings. These results suggest that both embryo-specific factor(s) and ABA are involved in the expression of the gene for ECP31.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027345
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    Electronic Resource
    Nucleotide sequence of a tobacco cDNA encoding plastidic glutamine synthetase and light inducibility, organ specificity and diurnal rhythmicity in the expression of the corresponding genes of tobacco and tomato (1992)
    Springer
    Plant molecular biology 19 (1992), S. 367-379 
    Details
    ISSN: 1573-5028
    Keywords: cDNA sequence ; gene expression ; glutamine synthetase ; phytochrome ; Solanaceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A full-length cDNA encoding glutamine synthetase (GS) was cloned from a λgt10 library of tobacco leaf RNA, and the nucleotide sequence was determined. An open reading frame accounting for a primary translation product consisting of 432 amino acids has been localized on the cDNA. The calculated molecular mass of the encoded protein is 47.2 kDa. The predicted amino acid sequence of this precursor shows higher homology to GS-2 protein sequences from other species than to a leaf GS-1 polypeptide sequence, indicating that the cDNA isolated encodes the chloroplastic isoform (GS-2) of tobacco GS. The presence of C-and N-terminal extensions which are characteristic of GS-2 proteins supports this conclusion. Genomic Southern blot analysis indicated that GS-2 is encoded by a single gene in the diploid genomes of both tomato and Nicotiana sylvestris, while two GS-2 genes are very likely present in the amphidiploid tobacco genome. Western blot analysis indicated that in etiolated and in green tomato cotyledons GS-2 subunits are represented by polypeptides of similar size, while in green tomato leaves an additional GS-2 polypeptide of higher apparent molecular weight is detectable. In contrast, tobacco GS-2 is composed of subunits of identical size in all organs examined. GS-2 transcripts and GS-2 proteins could be detected at high levels in the leaves of both tobacco or tomato. Lower amounts of GS-2 mRNA were detected in stems, corolla, and roots of tomato, but not in non-green organs of tobacco. The GS-2 transcript abundance exhibited a diurnal fluctuation in tomato leaves but not in tobacco leaves. White or red light stimulated the accumulation of GS-2 transcripts and GS-2 protein in etiolated tomato cotyledons. Far-red light cancelled this stimulation. The red light response of the GS-2 gene was reduced in etiolated seedlings of the phytochrome-deficient aurea mutant of tomato. These results indicate a phytochrome-mediated light stimulation of GS-2 gene expression during greening in tomato.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023384
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  • 38
    Electronic Resource
    Electronic Resource
    Structure of the pine (Pinus thunbergii) chlorophyll a/b-binding protein gene expressed in the absence of light (1992)
    Springer
    Plant molecular biology 19 (1992), S. 405-410 
    Details
    ISSN: 1573-5028
    Keywords: cab gene ; chlorophyll a/b-binding protein ; gymnosperm ; gene expression ; pine (Pinus thunbergii)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A gene for chlorophyll a/b-binding protein (cab) of pine (Pinus thunbergii) was isolated and sequenced. The gene (cab-6) contains an intron at a position equivalent to the type II cab genes of angiosperms. Transcript mapping analyses show that the amount of the mRNA in the dark is about half of that in the light. The cab-6 gene is expressed in dark-grown seedlings at a very high level, differing from angiosperm cab genes which are induced by light. The cab-6 gene typifies the coniferous plant cab genes in light-independent gene expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023388
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  • 39
    Electronic Resource
    Electronic Resource
    The heat shock response of pollen and other tissues of maize (1992)
    Springer
    Plant molecular biology 19 (1992), S. 623-630 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; heat shock ; intron ; maize ; pollen ; RNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract While a heat shock treatment of 40 °C or 45 °C induced the vegetative tissues of maize to produce the typical heat shock proteins (HSPs), germinating maize pollen exposed to the same temperatures did not synthesize these characteristic HSPs. Comparison of RNA accumulation in shoot and tassel tissue showed that mRNAs for HSP70 and HSP18 increased several-fold, reaching high levels within 1 or 2 hours. At the higher temperature of 45 °C these vegetative tissues were blocked in removal of an intron from the HSP70 mRNA precursor, which accumulated to a high level in tassel tissue. In germinating pollen exposed to heat shock, mRNAs for these HSPs were induced but accumulated only to low levels. The stressed pollen maintained high levels of RNA for α-tubulin, a representative normal transcript. It is likely that the defective heat shock response of maize pollen is due to inefficient induction of heat shock gene transcription.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00026788
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  • 40
    Electronic Resource
    Electronic Resource
    Pea dehydrins: identification, characterisation and expression (1992)
    Springer
    Plant molecular biology 19 (1992), S. 1031-1044 
    Details
    ISSN: 1573-5028
    Keywords: ABA ; dehydrin ; gene expression ; pea (Pisum sativum L.) ; seed development ; water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An antiserum raised against dehydrin from maize (Zea mays) recognised several polypeptides in extracts of pea (Pisum sativum) cotyledons. A cDNA expression library was prepared from mRNA of developing cotyledons, screened with the antiserum and positive clones were purified and characterised. The nucleotide sequence of one such clone, pPsB12, contained an open reading frame which would encode a polypeptide with regions of significant amino acid sequence similarity to dehydrins from other plant species. The deduced amino acid sequence of the pea dehydrin encoded by B12 is 197 amino acids in length, has a high glycine content (25.9%), lacks tryptophan and is highly hydrophilic. The polypeptide has an estimated molecular mass of 20.4 kDa and pI=6.4. An in vitro synthesised product from the clone comigrates with one of the in vivo proteins recognised by the antiserum. A comparison of the pea dehydrin sequence with sequences from other species revealed conserved amino acid regions: an N-terminal DEYGNP and a lysine-rich block (KIKEKLPG), both of which are present in two copies. Unexpectedly, pea dehydrin lacks a stretch of serine residues which is conserved in other dehydrins. B12 mRNA and dehydrin proteins accumulated in dehydration-stressed seedlings, associated with elevated levels of endogenous abscisic acid (ABA). Applied ABA induced expression of dehydrins in unstressed seedlings. Dehydrin expression was rapidly reversed when seedlings were removed from the stress or from treatment with ABA and placed in water. During pea cotyledon development, dehydrin mRNA and proteins accumulated in mid to late embryogenesis. Dehydrin proteins were some of the most actively synthesised at about the time of maximum fresh weight and represent about 2% of protein in mature cotyledons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040534
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  • 41
    Electronic Resource
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    Temporal and spatial regulation of a novel gene in barley embryos (1992)
    Springer
    Plant molecular biology 20 (1992), S. 255-266 
    Details
    ISSN: 1573-5028
    Keywords: barley (Hordeum vulgare) ; zygotic embryogenesis ; plant development ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The temporal and spatial pattern of expression of a novel barley gene is described. The gene has been identified through the differential screening of a cDNA library constructed to poly(A)+ RNA of zygotic embryos. Transcripts corresponding to the cDNA, pZE40, become abundant in the non-axial tissues of the developing embryo within 8–10 days after anthesis, when steady-state levels are high in the scutellum, coleoptile and coleorhiza, with the exception of the scutellar epithelium. This expression pattern is maintained throughout maturation of the embryo until levels eventually decline as the grain desiccates. On germination, there is a transient re-appearance of mRNA to pZE40, with accumulation specifically restricted to the scutellum of the seedling. In situ hybridization has enabled the detection of transcripts elsewhere in the barley plant, in highly localized groups of cells. The timing and cell specificity of expression suggests the gene product is involved in the synthesis and/or transport of metabolites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014493
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  • 42
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    Isolation and characterization of a tobacco gene with homology to pectate lyase which is specifically expressed during microsporogenesis (1992)
    Springer
    Plant molecular biology 20 (1992), S. 493-502 
    Details
    ISSN: 1573-5028
    Keywords: gene expression ; microsporogenesis ; Nicotiana tabacum ; pectate lyase ; pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A genomic clone has been isolated which contains an open reading frame of 1191 bp interrupted by two small introns. The ORF has been sequenced and the transcriptional start determined. The predicted amino acid sequence shows homology to the deduced amino acid sequences of two pollen-specific pectate lyase genes identified in tomato. The genomic clone was isolated using a partial cDNA clone, TP10, which had been isolated from a Nicotiana tabacum pollen cDNA library by means of differential screening. TP10 has been fully sequenced and contains an open reading frame of 792 bp which shows 96% homology to the ORF in the genomic clone. The transcript corresponding to TP10 is maximally expressed late in pollen development, and has not been detected in vegetative tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040608
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  • 43
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    cDNA cloning of a tetraubiquitin gene, and expression of ubiquitin-containing transcripts, in aleurone layers of Avena fatua (1992)
    Springer
    Plant molecular biology 20 (1992), S. 753-758 
    Details
    ISSN: 1573-5028
    Keywords: aleurone ; Avena fatua ; cDNA nucleotide sequence ; gene expression ; gibberellin ; polyubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A λgt11 cDNA library, constructed from poly(A)+ mRNA isolated from Avena fatua aleurone layers incubated with 1 μM gibberellin A1 (GA1) for 4 days, was screened with an anti-idiotypic antiserum raised against the GA-specific monoclonal antibody MAC 182. One positive clone was isolated, sequenced and shown to encode a tetraubiquitin based on the deduced amino acid sequence. This polyubiquitin cDNA exhibited a high degree of homology to a cloned wheat hexaubiquitin in its 3′-non-coding region. Analysis of total RNA isolated from A. fatua aleurone layers, treated without or with a range of concentrations of GA1 from 10-11 to 10-6 M, by northern blotting using the cDNA probe revealed 8 different ubiquitin-containing transcript classes all of which are constitutively expressed in aleurone and are regulated by GA1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046461
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  • 44
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    Ubiquitin genes are differentially regulated in protoplast-derived cultures of Nicotiana sylvestris and in response to various stresses (1992)
    Springer
    Plant molecular biology 20 (1992), S. 897-910 
    Details
    ISSN: 1573-5028
    Keywords: Cell division ; gene expression ; Nicotiana sylvestris ; protoplast ; stress ; ubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four ubiquitin mRNA size classes were found to be differentially regulated in mesophyll protoplast-derived cultures of Nicotiana sylvestris. Three mRNA families of 1.9, 1.6 and 1.35 kb were expressed as soon as protoplasts were isolated. The 1.9 and 1.6 kb size classes were transiently expressed during the first hours of culture, whereas the level of expression of the 1.35 kb size class was maintained as long as cells kept dividing. A 0.7 kb mRNA size class started to be expressed just before the first divisions were observed. cDNAs corresponding to each of these families were isolated from a 6-h-old protoplast cDNA library and characterized. The 1.9, 1.6 and 1.35 kb mRNAs thus encode 7- or more, 6- and 5- mers, respectively, of ubiquitin whereas the 0.7 kb mRNAs encode a monomer of ubiquitin fused to a carboxyl extension protein of 52 amino acids. The expression of ubiquitin genes was studied, using probes specific for each of these transcript families, during protoplast culture and, for comparison, after various stresses including heat shock, HgCl2 treatment, a viral infection giving rise to a hypersensitive reaction, and an Agrobacterium tumefaciens infection which resulted in tumour formation. The 1.9 and 1.6 kb mRNA size classes were found to be stress-regulated, the 0.7 kb mRNA size class developmentally regulated and the 1.35 kb size class both stress- and developmentally regulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027161
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  • 45
    Electronic Resource
    Electronic Resource
    Translation controls the expression level of a chimaeric reporter gene (1992)
    Springer
    Plant molecular biology 20 (1992), S. 921-938 
    Details
    ISSN: 1573-5028
    Keywords: β-D-glucuronidase ; mannopine synthase promoter ; Agrobacterium ; gene expression ; initiation of translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transcriptional and translational fusions between the reading frame of the β-D-glucuronidase gene (gusA) and the 2′ as well as the 1′ promoter of mannopine synthase (mas), a TR locus of Agrobacterium tumefaciens, were made. The expression of these constructs was studied in the transgenic F1 offspring of independent tobacco transformants at the protein level by assaying for GUS activity and western blot analysis of the GUS protein and at the steady-state mRNA level. In leaves, stems and roots no correlation was found between steady-state levels of GUS mRNA and enzyme activity. In older tissues significantly higher GUS activities were found. This is explained by the stable character of the GUS protein together with an accumulation of protein upon ageing. Three to ten times higher GUS activities were found for in vitro grown plants than for greenhouse-grown plants of the same offspring, despite similar levels of GUS mRNA. Roots from in vitro grown plants display three to ten times higher GUS activities than stems and leaves. In transgenic plants grown in vitro, containing a translational fusion with two AUGs in phase, the initiation of translation in leaf material occurred at both AUGs. Initiation of translation at the first AUG, however, was ten times more frequent. In contrast, initiation in roots from in vitro grown plants occurred exclusively at the second AUG.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027163
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  • 46
    Electronic Resource
    Electronic Resource
    A versatile binary vector system with a T-DNA organisational structure conducive to efficient integration of cloned DNA into the plant genome (1992)
    Springer
    Plant molecular biology 20 (1992), S. 1203-1207 
    Details
    ISSN: 1573-5028
    Keywords: Agrobacterium ; binary vector ; CaMV 35S ; gene expression ; β-glucuronidase ; Nicotiana plumbaginifolia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A versatile gene expression cartridge and binary vector system was constructed for use in Agrobacterium-mediated plant transformation. The expression cartridge of the primary cloning vector, pART7, comprises of cauliflower mosaic virus Cabb B-JI isolate 35S promoter, a multiple cloning site and the transcriptional termination region of the octopine synthase gene. The entire cartridge can be removed from pART7 as a Not I fragment and introduced directly into the binary vector, pART27, recombinants being selected by blue/white screening for β-galactosidase. pART27 carries the RK2 minimal replicon for maintenance in Agrobacterium, the ColE1 origin of replication for high-copy maintenance in Escherichia coli and the Tn7 spectinomycin/streptomycin resistance gene as a bacterial selectable marker. The organisational structure of the T-DNA of pART27 has been constructed taking into account the right to left border, 5′ to 3′ model of T-DNA transfer. The T-DNA carries the chimaeric kanamycin resistance gene (nopaline synthase promoter-neomycin phosphotransferase-nopaline synthase terminator) distal to the right border relative to the lacZ′ region. Utilisation of these vectors in Agrobacterium-mediated transformation of tobacco demonstrated efficient T-DNA transfer to the plant genome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028910
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  • 47
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    Ascorbic acid upregulates myelin gene expression in C6 glioma cells (1992)
    Springer
    Metabolic brain disease 7 (1992), S. 157-164 
    Details
    ISSN: 1573-7365
    Keywords: ascorbic acid ; proteolipid protein (PLP) ; myelin associated glycoprotein (MAG) ; gene expression ; C6 glioma cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of ascorbic acid (AA) on rat glioma C6 cells was studied. At physiological AA concentrations of 0.1 and 1 mM, no morphological and no proliferative alterations in the C6 cultures were detectable. Although the total RNA content per cell was not affected by the AA-treatment, AA upregulated the expression of myelin-specific genes, i.e. proteolipid protein (PLP) and myelin-associated glycoprotein (MAG) genes as assessed by northern blot analysis. The steady-state level of the specific mRNAs increased transiently in the AA-treated cells. Three days after AA administration the message level reached a maximum of 10-and 2-fold over control for the PLP and MAG genes, respectively. The upregulation of the genes was directly related to AA concentration. The present data indicate a possible involvement of AA in the regulation of myelin gene activity in the CNS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01000161
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  • 48
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    Electronic Resource
    Increased calmodulin affects cell morphology and mRNA levels of cytoskeletal protein genes (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 45-57 
    Details
    ISSN: 0886-1544
    Keywords: cell shape ; gene expression ; pleiotropic effects ; cell cycle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have previously described stable mouse C127 cell lines in which a CaM mini-gene has been expressed in a bovine papilloma virus-based expression vector (Rasmussen and Means: EMBO J. 6:3961-3968. 1987). Elevation of CaM to levels five-fold higher than in control cells caused an acceleration in cell cycle progression by reducing the length of the G1 period. When these cell lines were originally isolated it was observed that cells in which CaM levels were increased had a flattened morphology. In this study we have examined the localization of actin, vimentin, and tubulin in these cells as compared to the BPV-transformed control cell line in order to determine if changes in shape were accompanied by differences in the cytoskeletal organization. Cell-cycle-dependent changes in the levels of mRNAs for histone H4, glyceraldehyde-3-phosphate dehydrogenase, β-actin, vimentin, and β-tubulin have also been examined. Our results indicate that increased CaM causes differences in the organization of microfilaments, intermediate filaments, and microtubules and that these changes are accompanied by selective differences in the cell-cycle-dependent expression of some mRNAs. Elevated CaM was also correlated with a reduced stability of β-tubulin mRNA. These studies indicate that CaM has pleiotropic effects on cell function and suggest that stable cell lines with altered CaM levels may provide a useful model system for understanding the moiecular basis of CaM-dependent regulation of cellular processes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210106
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  • 49
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    Comparative analysis of the β transducin family with identification of several new members including PWP1, a nonessential gene of Saccharomyces cerevisiae that is divergently transcribed from NMT1 (1992)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 13 (1992), S. 41-56 
    Details
    ISSN: 0887-3585
    Keywords: fungal genes ; molecular cloning ; molecular sequence data ; gene expression ; database searching ; sequence alignment ; repetitive sequences ; signal transduction ; protein N-myristoylation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: While investigating the expression of the Saccharomyces cerevisiae myristoyl-CoA:protein N-myristoyltransferase gene (NMT: E.C. 2.3.1.97) by Northern blot analysis, we observed another RNA transcript whose expression resembled that of NMT1 during meiosis and was derived from a gene located 〈1 kb immediately upstream of NMT1. This new gene, designated PWP1 (for periodic tryptophan protein), is divergently transcribed from NMT1 and encodes a 576-residue protein. Null mutants of PWP1 are viable, but their-growth is severely retarded and steady-state levels of several cellular proteins (including at least two proteins that label with exogenous [3H]myristic acid) are drastically reduced. New methods for database searching and assessing the statistical significance of sequence similarities identic PWP1 as a member of the β-transducin protein superfamily. Two other previously unrecognized β-transducin-like proteins (S. cerevisiae MAKI1 and D. discoideum AAC3) were also identified, and an unexpectedly high degree of sequence homology was found between a Chlamydomonas β-like polypeptide and the C12.3 gene of chickens. A systematic and quantitative comparative analysis resulted in classifying all β-transducin-like sequences into II nonorthologous families. Based on specific sequence attributes, however, not all β-transducin-like sequences are expected to be functionally similar, and quantitative criteria for inferring functional analogies are discussed. Possible roles of repetitive tryptophan residues in proteins are also considered. Published 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340130105
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  • 50
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    Enantioselectivity of lipase-catalyzed hydrolysis of some 2-chloroethyl 2-arylpropanoates studied by chiral reversed-phase liquid chromatographySecond International Symposium on Chiral Discrimination, May 27 - 31, 1991, Rome, Italy. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 98-102 
    Details
    ISSN: 0899-0042
    Keywords: enantioselective hydrolysis ; lipase ; 2-chloroethyl esters ; 2-arylpropanoic acids ; chiral liquid chromatography ; enantiomer separation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A technique based exclusively on chiral reversed-phase liquid chromatography has been shown to greatly facilitate studies of enantioselectivity in lipase-catalyzed hydrolysis of chiral organic esters. Only two sets of experimental data are needed to calculate the enantioselectivity (E) of a kinetically controlled enantiomer-differentiating reaction of this kind, viz. the enantiomeric excess of the product (eep) or substrate (ees), and the degree of substrate conversion (c). The product enantiomers are well separated on a BSA-based column, giving eep directly. In addition, separation of the (unresolved) ester substrate from the enantiomeric products gives c by integration. Via an optimization of the mobile phase used in the chiral chromatographic system, both these parameters can often be determined in a single run. Highly precise and detailed kinetic studies of the enzymatic reaction can thus be performed. In this way, E-values have been determined for a series of 2-chloroethyl 2-arylpropanoates hydrolyzed in the presence of a Candida cylindracea lipase at pH 6.0 and 7.1. Effects on the E-values from a partial purification and further processing of the lipase have also been studied.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040206
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    Enzymatic resolutions of α- and β-hydroxypropionic acid esters (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 103-109 
    Details
    ISSN: 0899-0042
    Keywords: dihydrocinnamic acid derivatives ; hydroxy azido acids ; hydroxy amino acids ; enantioselective hydrolysis ; Pseudomonas fl. lipase ; Candida cyclindracea lipase ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of some acyloxy-methoxy-cinnamic acid derivatives, azidohydroxy butanoates, and azidohydroxy butanedioates in enantiomerically pure form is presented. Racemic diastereomerically pure educts were prepared in few steps. These racemates are resolved with lipases from Candida cylindracea (CC) and Pseudomonas fluorescens (P).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040207
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  • 52
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    Optical resolution of β-lactams on 1-phenylethylcarbamates of cellulose and amylose (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 122-124 
    Details
    ISSN: 0899-0042
    Keywords: 4-acetoxy-2-azetidinone ; antibiotics ; carbapenem ; HPLC ; chiral stationary phases ; cellulose tris(1-phenylethylcarbamate) ; amylose tris(1-phenylethylcarbamate) ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical resolution of six β-lactams was examined by HPLC using chiral stationary phases consisting of tris((R)-, (RS)-, and (S)-1-phenylethylcarbamate)s of cellulose and amylose. All β-lactams were optically resolved at least by one of the carbamates. Amylose tris((S)-1-phenylethylcarbamate) showed high optical resolving abilities for some β-lactams.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040210
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  • 53
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    Cyclodextrin derivatives in GC separation of racemic mixtures of volatiles: Part IIISecond International Symposium on Chiral Discrimination, May 27 - 31, 1991, Rome, Italy. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 125-131 
    Details
    ISSN: 0899-0042
    Keywords: capillary gas chromatography ; enantiomer resolution ; cyclodextrin derivatives ; chromatographic performance ; cyclodextrin/OV-1701 dilution ; operative temperature ; film thickness ; column length ; column conditioning ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas chromatographic performance of differently derivatized α-, β-, and γ-cyclodextrins in the separation of racemic mixtures of volatiles is investigated. The performances of 2,3,6-permethylated α-, β-, and γ;-cyclodextrins and 2,6-dimethyl-3-trifluoro-acetyl α-, β-, and γ-cyclodextrins mixed with different ratios of OV-1701 or OV-1701-OH terminated were tested with racemates with widely differing structures. The influence of the percentage of cyclodextrins in polysiloxane, of film thickness of the stationary phase, of the length of the column, of column conditioning, and of the operating temperatures in the separations of different racemates has been evaluated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040211
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    Stereoselective disposition and tissue distribution of carvedilol enantiomers in rats (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 148-154 
    Details
    ISSN: 0899-0042
    Keywords: carvedilol enantiomers ; kinetics ; tissue-to-blood partition coefficient ; plasma protein binding ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: After intravenous bolus injection of rac-carvedilol at 2 mg/kg to the rat, the (+)-(R)- and ( - )-(S)-enantiomer levels in the blood and tissues (liver, kidney, heart, muscle, spleen, and aorta) were measured by stereospecific HPLC assay. As compared with the (+)-(R), the ( - )-(S) had a larger Vdss (3.32 vs. 2.21 liter/kg), MRT (33.4 vs. 25.6 min), and CLtot (96.1 vs. 83.8 ml/min/kg). AUC comparison after iv and po administration showed systemic bioavailability of the ( - )-(S) to be about half that of its antipode, explained by the fact that the free fraction of the ( - )-(S) in blood was 1.65-fold greater than that of the (+)-(R). Tissue-to-blood partition coefficient values for the ( - )-(S) were 1.6- to 2.1-fold greater than those for the (+)-(R) in all tissues, showing that the ( - )-(S) accumulates more extensively in the tissues. These results were consistent with the greater Vdss for the ( - )-(S) estimated from systemic blood data. The stereoselective tissue distribution of carvedilol enantiomers results from an enantiomeric difference in plasma protein binding rather than in tissue binding. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040304
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    Liquid chromatographic separation of chiral diarylcarbinolsSecond International Symposium on Chiral Discrimination, May 27-31, 1991, Rome, Italy. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 170-173 
    Details
    ISSN: 0899-0042
    Keywords: chiral phases ; chiral recognition mechanism ; alcohols ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The direct HPLC separation of three chiral carbinols of general formula Mesityl-CH(OH)-Aryl has been achieved using Pirkle (R)-DNBPG ionic or covalent columns and, for Aryl = o-tolyl, on a Chiralpak OP(+) phase. It is apparent that steric hindrance and hydrogen bonding play important roles in chiral recognition. Two compounds structurally very similar but lacking the hydroxyl group were not resolved in their enantiomeric pairs. © 1992 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040307
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    Masthead (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992) 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040401
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  • 57
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    Spontaneous racemization of chlorthalidone: kinetics and activation parameters (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 222-226 
    Details
    ISSN: 0899-0042
    Keywords: 3-hydroxy-3-phenylphthalimidines ; inversion (of configuration) ; barrier to inversion ; rate constants (of inversion) ; enantiomer interconversion ; carbonium ion (intermediate in racemization) ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enantiomers of chlorthalidone (CTD) and a minor, achiral dehydration product, δ2-CTD, are shown to exist in dynamic equilibrium in aqueous media through a carbonium ion intermediate. The barrier to inversion at carbon is low for an uncatalyzed system: ΔG
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040404
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    Stereoselective binding of etodolac to human serum albuminPresented at the Second International Symposium on Chiral Discrimination, May 27-31, 1991, Rome, Italy. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 240-246 
    Details
    ISSN: 0899-0042
    Keywords: NSAID ; chirality ; enantiomers ; protein binding ; equilibrium dialysis ; fluorescent specific markers ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The protein binding of etodolac enantiomers was studied in vitro by equilibrium dialysis in human serum albumin (HSA) of various concentrations varying from 1 to 40 g/liter, by addition of each enantiomer at increasing concentrations. In the 1 g/liter solution, at the lowest drug levels, the (R)-form is more bound than its antipode, the contrary being observed at the highest drug levels. For higher albumin concentrations, S was bound in a larger extent than R. Using the displacement of specific markers of HSA sites I and II, studied by spectrofluorimetry, it was suggested that R and S are both bound to site I, while only S is strongly bound to site II. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040407
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    Resolution of terfenadine enantiomers by β-cyclodextrin chiral stationary phase high-performance liquid chromatography (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 268-272 
    Details
    ISSN: 0899-0042
    Keywords: HPLC ; chiral stationary phase ; optical isomers ; absolute configuration ; circular dichroism ; chiral ; enantiomers ; terfenadine ; cyclodextrin ; normal phase ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantiomers of terfenadine were resolved by high-performance liquid chromatography (HPLC) using a chiral stationary phase (CSP) column packed with β-cyclodextrin (β-CD) covalently bound to silica. Separation was achieved in both the reverse phase and normal phase modes. Resolution of enantiomers was confirmed by ultraviolet-visible absorption, circular dichroism, and mass spectral analysis.
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    Obituary: professor goran schill (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 273-273 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040502
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    Effects of the stereochemical orientation of phenethylamines and imidazolines on α-adrenergic receptor-mediated dna synthesis in primary cultured rat hepatocytes (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 279-285 
    Details
    ISSN: 0899-0042
    Keywords: stereochemistry ; catecholamines ; DNA synthesis ; liver regeneration ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hepatic α1-adrenergic receptor mediates a variety of hepatic functions including respiration, glycogenolysis, gluconeogenesis, and growth. We have utilized a rat primary hepatocyte culture system to show that the α1-adrenergic receptor can be activated in a stereoselective manner by a series of phenethylamines and catecholimidazolines resulting in the stimulation of DNA synthesis as determined by [3H]thymidine incorporation. The phenethylamines adhered to the Easson-Stedman hypothesis with a rank order of potency of (-)-(R)-norepinephrine (NE) 〉 (+)-(S)-NE 〉 the desoxy analog dopamine (DA) for the stimulation of DNA synthesis. However, the 2-substituted catecholimidazolines did not follow this trend and demonstrated an order of potency of the desoxy analog 3,4-dihydroxybenzyl imidazoline (DHT) ≥ (-)-(R)-2-(3,4,α-trihydroxybenzyl)imidazoline (TBI) 〉 (+)-(S)-TBI. 4-Substituted catecholimidazolines were less potent as inducers of DNA synthesis than the corresponding 2-substituted analogs with an order of potency of (+)-(R)-4-(3,4-dihydroxybenzyl)imidazoline (DBI) 〉 (+, -)-(R,S)-DBI 〉 (-)-(S)-DBI. When the β-hydroxyl moiety of NE is replaced with an amino group as in 3,4-dihydroxyphenylethylenediamine, the isomers are less active than the β-hydroxylated analogs and also demonstrate no stereoselectivity for the stimulation of DNA synthesis. These results demonstrate that the hepatic α1-adrenergic receptor can recognize various isomeric forms of these compounds and that hepatocellular growth can be modulated in a stereoselective manner by phenethylamines and imidazolines. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040504
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    Some mechanistic aspects on chiral discrimination of organic acids by immobilized bovine serum albumin (BSA) (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 24-29 
    Details
    ISSN: 0899-0042
    Keywords: organic acids ; enantiomers ; BSA ; chiral discrimination ; hydrophobic interaction ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Although chiral anionic compounds, notably a large number of organic acids, have been found to be readily separated into enantiomers on BSA-based columns, the structural requirements for an efficient enantiomer discrimination by the protein is still not very well known. Since it is often observed that very hydrophobic acids, like many of the antiinflammatory “profens,” can be resolved with large separation factors for the enantiomers, a systematic study of a series of racemic α-substituted alkanoic acids was made. The series of analytes was prepared from α-amino acids, RCH(NH2)CO2H (where R = C1-C6), by reaction with N-(chloroformyl)-carbazole. A rapid increase in the capacity ratios of both enantiomers was found with increasing length of R. The effect, however, was larger for the last eluted enantiomer, leading to a substantial increase in the separation factor; this being 7.3 for R = C6 in 20 mM phosphate buffer (pH 8.0) with 30% of acetonitrile. Further, the separation factor also increased with decreasing organic modifier content. Thus when the R = C6-analyte was run at a mobile phase concentration of 20% acetonitrile and a flow rate of 1.5 ml/min, the time difference between the two eluted enantiomers exceeded 20 hr.A reasonable interpretation of our results seems to be that enantioselectivity is promoted by increased hydrophobic interaction. Since the anionic charge of the analyte is also taking part in the retention mechanism, a tight binding of the analyte will result from simultaneous electrostatic and hydrophobic interaction. When the latter is increased, less conformational freedom will be left for the analyte and the steric configuration at the α-carbon atom will become more and more important. Steric hindrance by the α-substituent in the first eluted enantiomer will counteract the tight binding caused by the combined binding interactions and lead to a smaller increase in the capacity ratio.
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    URL: http://dx.doi.org/10.1002/chir.530040107
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    4',6-Dichloroflavan (BW683C): Enantiomeric separation by hplc/dad and antirhinovirus activity (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 65-67 
    Details
    ISSN: 0899-0042
    Keywords: optical resolution ; chiral HPLC ; chiral stationary phase ; 4',6-dichloroflavan ; circular dichroism ; antirhinovirus activity ; BW683C ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Racemic 4',6-dichloroflavan (BW683C), a highly effective inhibitor of rhinovirus serotype 1B in vitro, was resolved by high-performance liquid chromatography on a chiral stationary phase. The enantiomers were separately collected and circular dichroism curves were obtained, in order to determine the absolute configuration of the two enantiomers. The activity of the isomers was studied on human rhinovirus serotype 1B multiplication in HeLa cell cultures, by means of the plaque reduction assay. Both enantiomers were potent inhibitors of virus replication; by comparing the IC50 values, the S form was 3.5 times more effective than the R form.
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    URL: http://dx.doi.org/10.1002/chir.530040114
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    Erratum (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 71-71 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040116
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    Pulmonary inversion of 2-arylpropionic acids: Influence of protein binding (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 349-352 
    Details
    ISSN: 0899-0042
    Keywords: ibuprofen ; fenoprofen ; flurbiprofen ; rabbit lung ; first-pass ; presystemic ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The possible contribution of pulmonary metabolism to the putative first-pass metabolism of 2-arylpropionic acid nonsteroidal antiinflammatory drugs has not been documented. Isolated perfused rabbit lungs, perfused with 4.5% bovine serum albumin or 5% dextran, were used to study the pulmonary elimination of (R)- and rac-ibuprofen, fenoprofen, and flurbiprofen. In the absence of protein binding, ibuprofen was metabolized via inversion and other pathways, whereas fenoprofen metabolism was essentially restricted to inversion of the (R)-enantiomer; fraction inverted (± SE) was 0.37 ± 0.05 for (R)-ibuprofen and 0.85 ± 0.03 for (R)-fenoprofen. In the presence of protein, neither ibuprofen nor fenoprofen was metabolized. Flurbiprofen did not undergo pulmonary elimination under any condition studied. This study illustrates that even though a tissue is capable of metabolism, particularly inversion of 2-arylpropionics, the quantitative importance of such elimination pathways may be minimal in the presence of the high degree of protein binding that is characteristic of these drugs. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040604
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    Formation of glycine conjugate and (-)-(R)-enantiomer from (+)-(S)-2-phenylpropionic acid suggesting the formation of the coa thioester intermediate of (+)-(S)-enantiomer in dogs (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 342-348 
    Details
    ISSN: 0899-0042
    Keywords: arylpropionic acid ; 2-phenylpropionic acid ; glycine conjugation ; stereoselectivity ; chiral inversion ; reverse chiral inversion ; glycine N-acyl transferase ; dog hepatocytes ; chiral HPLC ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It has been proposed that the chiral inversion of the 2-arylpropionic acids is due to the stereospecific formation of the (-)-R-profenyl-CoA thioesters which are putative intermediates in the inversion. Accordingly, amino acid conjugation, for which the CoA thioesters are obligate intermediates, should be restricted to those optical forms which give rise to the (-)-R-profenyl-CoA, i.e., the racemates and the (-)-(R)-isomers. We have examined this problem in dogs with respect to 2-phenylpropionic acid(2-PPA). Regardless of the optical configuration of 2-phenylpropionic acid administered, the glycine conjugate was the major urinary metabolite and this was shown to be exclusively the (+)-(S)-enantiomer by chiral HPLC. Both (-)-(R)- and (+)-(S)-2-phenylpropionic acid were present in plasma after the administration of either antipode, and further evidence of the chiral inversion of both enantiomers was provided by the presence of some 25% of the opposite enantiomer in the free 2-phenylpropionic acid and its glucuronide excreted in urine after administration of (-)-(R)- and (+)-(S)-2-phenylpropionic acid. The (+)-(S)-enantiomer underwent chiral inversion to the (-)-(R)-antipode when incubated with dog hepatocytes. These data suggests that both enantiomers of 2-phenylpropionic acid are substrates for canine hepatic acyl CoA ligase(s) and thus undergo chiral inversion, but that the CoA thioester of only (+)-(S)-2-phenylpropionic acid is a substrate for the glycine N-acyl transferase. These studies are presently being extended to the structure and species specificity of the reverse inversion and amino acid conjugation of profen NSAIDs. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040603
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    HPLC resolution of atropoisomeric compounds on a csp derived from (1R;2R)-diaminocyclohexane: Thermodynamic data from variable temperature chromatographyThis paper was presented at the Second International Symposium on Chiral Discrimination, May 27-31, 1991, Rome, Italy. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 384-388 
    Details
    ISSN: 0899-0042
    Keywords: enantiomeric separations ; polymeric CSPs ; enthalpy ; entropy ; H-bonding ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation and a preliminary chromatographic evaluation of a novel polymeric chiral stationary phase (CSP) derived from (1R;2R)-diaminocyclohexane (DACH) are presented. A radical copolymerization process has been employed to generate a silica-based chiral sorbent, showing considerable high chemical and thermal stability and stereoselectivity toward racemic compounds capable of H-bonding (3-hydroxy-benzodiazepin-2-ones, chlorthalidone, atropoisomeric sulfur compounds, etc.); in the present paper we present the investigation on the resolution of racemic dihydroxy biarylic atropoisomers; the effects of eluent composition and of temperature on the separation ability of the CSP have been studied in order to elucidate the recognition mechanism operating in these chiral separations. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040609
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    Announcement (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 406-406 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040614
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    Masthead (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992) 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040701
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    Optical resolution of unusual amino acids using microbial proteases (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 427-431 
    Details
    ISSN: 0899-0042
    Keywords: enantioselective hydrolysis ; amino acid enantiomers ; Aspergillus oryzae protease ; Bacillus subtilis protease ; enantioselectivity ; enantiomeric purity determination ; HPLC ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have developed novel enzymatic methods for the optical resolution of unusual amino acids. In this work, we tried two microbial proteases, available inexpensively in a crude state, from Aspergillus oryzae and from Bacillus subtilis. The enantioselective hydrolysis of the methyl esters of the N-benzyloxycarbonyl (Z) derivatives of a number of amino acids, both aliphatic and aromatic, was examined using these microbial proteases. The enantiomeric purities of the resolved Z-amino acids were determined accurately by methods based on the reversed-phase HPLC separation of diastereomeric derivatives or the HPLC separation of enantiomeric derivatives on chiral stationary phases. In general, B. subtilis protease yielded better results than A. oryzae protease. Using the former protease, the amino acids bearing aliphatic side chains were resolved with good to excellent enantioselectivities and reasonable hydrolysis rates. The speed of hydrolysis was reduced significantly when the length of the side chain was longer than 5 carbon atoms. Phenylalanine, halogenated phenylalanines, and phenylalanine homologs were also resolved, generally with high enantiomeric purities, though the hydrolysis rates were not always reasonably fast. In all the cases examined, the L-enantiomers were preferentially hydrolyzed as in the lipase-catalyzed enantioselective hydrolysis reported previously. © 1992 Wiley-Liss, Inc.
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    Resolution and adrenergic activities of the optical isomers of 4-[1-(1-Naphthyl)ethyl]-1H-imidazole (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 432-438 
    Details
    ISSN: 0899-0042
    Keywords: α-adrenergic ; imidayole analogs ; metetomidine ; enantiomers ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recently we synthesized a naphthalene analog of medetomidine, 4-[1-(1-naphthyl)ethyl]-1H-imidazole hydrochloride (1), and found it to be highly potent in adrenergic systems. The separation of optical isomers of this naphthalene analog was achieved by using the isomers of tartaric acid. The optical purities of the isomers were determined by HPLC using a chiral column. Using X-ray analysis the (+)-isomer was determined to have the S absolute configuration. It has been reported that the (+)-isomer of medetomidine (2) is the most potent enantiomer on α2-adrenergic receptors. There were both qualitative and quantitative differences in biological activities of the optical isomers of 1 in α1- and α2-adrenergic receptor systems of guinea pig ileum and human platelets. (+)-(S)-1, but not ( - )-(R)-1 was a selective agonist of α2-mediated responses in ileum whereas ( - )-(R)-1 was more potent than (+)-(S)-1 as an inhibitor of α2-mediated platelet aggregation. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040706
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    Announcement (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 462-463 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040711
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    Optical stability of gossypol (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 216-221 
    Details
    ISSN: 0899-0042
    Keywords: atropisomerism ; gossypol stereochemistry ; molecular mechanics ; circular dichroism ; anhydrogossypol ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The optical stability of gossypol [1,1',6,6',7,7'-hexahydroxy-3,3'-dimetyl-5,5'-bis(1-methylethyl)-2,2'-binaphthalene-8,8'-dicarboxaldehyde], a natural product exhibiting profoundly enantiospecific antitumor and male antifertility action, was investigated by means of computational methods and thermal racemization experiments. The calculations on gossypol and several derivatives and model compounds were carried out using the MM2 force field; energies and geometries of minimum energy conformations, as well as structures along various inversion pathways, were calculated. According to the calculations, gossypol (the dialdehyde form) and its simple analogues are not thermally racemizable (energy barriers for rotational inversion above 50 kcal/mol). By contrast, the calculations suggest that the acetal tautomer of gossypol and its dehydration product (anhydrogossypol) are thermally racemizable, although the energy barriers are still relatively high (35-40 kcal/mol). Optically pure (+)-anhydrogossypol was prepared and characterized; its racemization became rapid only at high temperatures (180-200°C). When dehydration of gossypol was hindered (in aqueous solution), no racemization of gossypol was observed after prolonged heating at 90°C. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040403
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    Synthesis and pharmacological investigation of stereoisomeric muscarines (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 230-239 
    Details
    ISSN: 0899-0042
    Keywords: total synthesis ; chiral muscarines ; iodocyclization process ; muscarinic receptor subtypes M1, M2, and M3 ; affinity states ; eudismic ratio ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the eight stereoisomers of muscarine has been efficiently accomplished by utilizing the two enantiomers of lactic esters as starting material. The synthetic strategy is based on a SnCl4-catalyzed addition of allyltrimethylsilane to O-protected lactic aldehydes followed by an iodocyclization process. All the final derivatives possess an enantiomeric excess higher than 98%. The four pairs of enantiomers bound to M1, M2, and M3 muscarinic receptor subtypes in membranes from cerebral cortex, heart, and salivary glands, respectively, and recognized heterogeneous states of the receptors. Of the eight isomers, only natural muscarine (+)-1 recognized three affinity states of the M2 receptor. The compound was also the only one to show selectivity in the binding study, demonstrating 37- to 44-fold higher affinity for the M2 than for the M1 or M3 receptors. In addition, the compounds were tested in functional assays on isolated guinea pig atria (M2 receptors) and ileum (mixed population of M2 and M3 receptors) and their muscarinic potencies were determined. Among the eight isomers, again only (+)-1 enantiomer was found to be very active on both tissues. Its potency was more than two orders of magnitude higher than that of its enantiomer (-)-1 as well as the other six isomers. The eudismic ratios (E.R.) deduced from the two functional tests were 324 and 331. © 1992 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040406
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    Discrimination in resolving systems: Ephedrine-mandelic acid (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 494-504 
    Details
    ISSN: 0899-0042
    Keywords: diastereomers ; crystal structures ; isosterism ; organic salts ; molecular recognition ; hydrogen bonding ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Resolution of mandelic acid with ( - )-(1R,2S)-ephedrine in water and ethanol produces intermediate diastereomeric salts with greatly disparate solubilities and melting points. Single crystal X-ray analysis of the less (L) and more (M) soluble ( - )-ephedrinium mandelates (I, II) shows crystal structures which are isosteric, each crystallizing in the monoclinic system, space group C2. Protonated ephedrines occupy the same relative positions in the L- and M-salts, and mandelates are in the same general locations. Hydrogen bonds link alternating protonated ephedrine nitrogens and mandelate carboxylate oxygens in each salt forming columns of ions. The helical H-bonded chain winds down the crystallographic 2-fold screw axis. Additional H-bonds form between 2-fold related mandelates in the L-salt. Mixed crystals, containing both mandelate isomers, (2R)- and (2S)-mandelates, are obtained from the resolving system partly depleted of the L-salt. A specimen with nearly equal amounts of the mandelates (III) is also isosteric with the commensurate structures. I (294K), L-salt: a = 18.160(7), b = 6.538(2), c = 13.898(4) Å, β = 92.02(3)°, V = 1649.1(9) Å3; IIa (294K), M-salt: a = 17.978(11), b = 7.164(4), c = 13.574(6)Å, β = 96.41(4)°, V = 1737.3(16) Å3; IIb (223K), M-salt: a = 17.805(8), b = 7.115(2), c = 13.50(5) Å, β = 96.89(3)°, V = 1697.9(15) Å3; III (294K), mixed-salt: a = 18.184(22), b = 6.792(7), c = 13.808(19) Å, β = 93.74(10)°, V = 1701.7(35) Å3. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040807
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    High enantiofacial selectivity in the OsO4 dihydroxylation of e-stilbene with a chiral biphenyl diamine catalyst (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 300-301 
    Details
    ISSN: 0899-0042
    Keywords: hydrobenzoin ; asymmetric oxidation ; osmium tetroxide ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chiral biphenyl-containing diamine 1 complexed with OsO4 oxidized trans-stilbene at -80°C to (+)-(1R;2R)-1,2-diphenyl-1,2-ethanediol in high enantiomeric excess. On the other hand, (R)- or (S)-2,2'-bis(dimethylamino)-6,6'-dimethylbiphenyl proved to be ineffective in promoting oxidation. © 1992 Wiley-Liss, Inc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040507
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    Enantio- and regioselectivity in the epoxide-hydrolase-catalyzed ring opening of aliphatic oxiranes: Part II: Dialkyl- and trialkylsubstituted oxiranes (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 185-192 
    Details
    ISSN: 0899-0042
    Keywords: enantioselective hydrolysis ; regioselective hydrolysis ; epoxide hydrolase ; product enantioselectivity ; substrate enantioselectivity ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The extent of substrate enantioselectivity and regioselectivity of a series of aliphatic 2,3-dialkyl- and trialkylsubstituted oxiranes in their in vitro epoxide-hydrolase-catalyzed hydrolysis depends on the size of the alkyl residues and on the substitution pattern of the oxirane ring. The enzyme-catalyzed hydrolysis of cis-oxiranes, containing at least one methyl substituent, shows complete or nearly complete substrate enantioselectivity and regioselectivity with nucleophilic attack by water occurring with inversion of configuration at the methylsubstituted ring carbon atom of (S)-configuration. In the hydrolysis of the isomeric trans-oxiranes, both enantiomers are metabolized with a higher rate for the (2S;3S)-enantiomer. The conversion of trimethyloxirane occurs with high substrate enantioselectivity in favor of the (S)-enantiomer and with complete regioselectivity at the monomethylsubstituted ring carbon atom. The differentiation of the enantiotopic ring carbon atoms (product enantioselectivity) in the smallest aliphatic meso-oxirane, cis-2,3-dimethyloxirane, leads to (2R;3R)-butane-2,3-diol with ee = 86%. cis-2-Ethyl-3-propyloxirane, possessing alkyl residues larger than methyl, represents an extremely poor substrate in the epoxide-hydrolase-catalyzed hydrolysis process. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040310
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    Structural characteristics of cyclodextrins in the solid state (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 205-215 
    Details
    ISSN: 0899-0042
    Keywords: cyclodextrins ; molecular mechanics ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A comparison of α-, β and γ-cyclodextrins in the solid state is made. Monomeric features analyzed include orientations of primary hydroxyl groups and pyran ring pucker. Macromolecular features examined include planarity of the oligomer, tilting of pyran rings, and, deviation from Cn symmetry where n = number of monomers. The mean values and standard deviations of these shape descriptors are given for cyclodextrins with and without guests embedded in their interiors. Molecular mechanics calculations using the MM2, AMBER, and CHARMM force fields show that most solid state cyclodextrins are trapped in high-energy conformations relative to the most stable forms found in this study. © 1992 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040402
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    Enzymes in stereoselective pharmacokinetics of endogenous substancesPresented at the Second International Symposium on Chiral Discrimination, May 27-31, 1991, Rome, Italy. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 247-251 
    Details
    ISSN: 0899-0042
    Keywords: radioenzyme assay ; stereospecific assay ; carnitine acetyl transferase ; L-carnitine family ; L-carnitine ; acetyl-L-carnitine ; propionyl-L-carnitine ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of enzymes to assay individual components of the L-carnitine family in pharmaceuticals, foodstuffs, and biological fluids with various forms of detection is reviewed. The most useful enzyme in the assay of compounds of the L-carnitine family is carnitine acetyl transferase (CAT), which catalyses the reversible interconversion of L-carnitine and its short-chain acyl esters. CAT can be used in one or more coupled reactions combined with U.V., or radiolabelled detection, or combined with HPLC, allowing, enantioselective, structurally specific, and, in the case of radiolabelled tracing, highly sensitive assays to be carried out. When compared with chromatographic separation of enantiomers or diastereoisomers, enantioselective enzyme mediated assays may be cheaper, more sensitive, and simpler, but they do not allow the nonpreferred isomer to be assayed. Consequently, they are appropriate for the specific assay of endogenous enantiomeric substrates of the enzyme concerned, in biological samples. The analysis of the other enantiomer in raw materials or in pharmaceuticals must be more properly approached by enantioselective chromatographic methods.
    Additional Material: 1 Ill.
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    Direct enantiomeric separation of β-blockers on ChyRoSine-a by supercritical fluid chromatography: Supercritical carbon dioxide as transient in situ derivatizing agent (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 252-262 
    Details
    ISSN: 0899-0042
    Keywords: enantiomeric separations ; chiral stationary phases ; tyrosine chiral selector ; supercritical fluid chromatography ; 1,2-amino-alcohols ; β-blockers ; carbon dioxide ; 1H NMR ; ChyRoSine CSP ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The direct enantiomeric separation of a series of β-blockers has been carried out on two chiral stationary phases (CSPs) derived from 3,5-dinitrobenzoyl tyrosine: the commercially available ChyRoSine-A and a recent improved version of this CSP.Using supercritical fluid chromatography (SFC), facile separations are achieved (1.1 〈Rs 〈7) within short analysis times. The parameters affecting the enantioselectivity (temperature, pressure, mobile phase nature, solute structure) have been investigated. The optimal mobile phase consists in a mixture of carbon dioxide-methanol-propylamine at 25°C. The solute structure has a great influence on the enantioselectivity. For instance, both amine and hydroxyl protons are necessary for chiral discrimination to occur. Furthermore, the steroselectivity value is directly connected to the amine substituent steric bulkiness.Surprisingly, these solutes are poorly resolved using normal phase liquid chromatography (NPLC). Accordingly, the specific influence of carbon dioxide on the enantiomeric separation of 1,2-amino-alcohols has been investigated using various techniques such as nuclear magnetic resonance (NMR) or molecular modelisation. It has been shown that carbon dioxide acts as a complexing agent toward the amino-alcohol by setting up of a bridge with the hydroxyl and the amine protons of the solute. In that way, the resulting complex possesses lower acido-basic properties and a higher conformational rigidity, responsible for chiral discrimination.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040409
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    A proposal for the representation of the stereochemistry of quadrivalent centers (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 274-278 
    Details
    ISSN: 0899-0042
    Keywords: one-wedge diagram ; structure representation ; stereochemistry ; absolute configuration ; chiral center ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The broken wedge, broken line, solid bar, and broken bar are either not reasonable or can be replaced by only one type of solid wedge in the stereochemical formulation. A convention based on a one-wedge symbolization is proposed, where a or b is used instead of c, d, e, f, g, or h. © 1992 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040503
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    Asymmetric synthesis polymerization of meso oxiranes and thiiranesThis work is dedicated to the memory of Professor Piero Pino. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 295-299 
    Details
    ISSN: 0899-0042
    Keywords: cis-dimethylthiirane ; cyclohexene sulfide ; cis-dimethyloxirane ; cyclohexene oxide ; chiral initiator system ; enantiogenic polymerization ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The asymmetric synthesis polymerization or “enantiogenic” polymerization of some meso oxiranes, cis-dimethyloxirane (cis-DMO) and cyclohexene oxide (CHO), and thiiranes, cis-dimethylthiirane (cis-DMT) and cyclohexene sulfide (CHS), initiated with different chiral systems was examined. Strong differences in behaviour were observed between oxiranes and thiiranes depending on the initiator used. The initiators based on ZnEt2 or CdMe2 and a chiral diol give optically active polymers from meso thiiranes but fail to induce an asymmetric polymer synthesis with meso oxiranes. A new chiral initiator based on ZnEt2 and (1S,2R)-ephedrine allowed us to prepare optically active poly CHOs, which can be fractionated into fractions exhibiting opposite optical activities. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040506
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    Computer-Aided models for optimization of eluent parameters in chiral liquid chromatography (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 316-322 
    Details
    ISSN: 0899-0042
    Keywords: chiral LC ; drug enantiomers ; modelling ; central composite desire ; optimization ; β-cyclodextrin ; response surface ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of a central composite design to the enantiomeric separation of the antifungal drug tioconazole is investigated. The design involves application of a mathematical model to the data to model the response in regions of the factor space not investigated in the experimental design. The significance of the variable terms in the model is assessed statistically and those terms declared not significant are removed from the model. The statistical adequacy of these reduced models is discussed, together with an examination of the prediction errors of the models. Three-dimensional predicted response surfaces for the complete models are presented and the predictive performance assessed. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040510
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    Resolution of the enantiomers of drugs containing amino alcohol structure after derivatization with bromoacetic acid (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 333-337 
    Details
    ISSN: 0899-0042
    Keywords: chiral separation ; ligand exchange chromatography ; adrenergic drugs ; β-blockers ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The separation of the enantiomers of drugs containing an amino alcohol structure like adrenergic drugs or β-blockers is described. The compounds are resolved on chiral ligand-exchange chromatography phases after derivatization with bromoacetic acid. © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/chir.530040512
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    Masthead (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992) 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040601
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  • 86
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    Optical isomers of a leukotriene b4 antagonist have differential effects on granulocyte diapedesis in the guinea pig dermis (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 353-355 
    Details
    ISSN: 0899-0042
    Keywords: leukotriene B4 ; SC-41930 ; dermis ; granulocyte ; stereoselectivity ; guinea pig ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Leukotriene B4 (LTB4) is a proinflammatory product of arachidonic acid metabolism that has been implicated in a number of inflammatory diseases. When injected intradermally into the guinea pig, LTB4 has been shown to elicit a dose-dependent infiltration of granulocytes as assessed by the level of the neutrophil marker enzyme myeloperoxidase. SC-41930 [7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)propoxy]-3,4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid] is a potent LTB4 receptor antagonist. When compounds were coadministered along with LTB4 (35 ng) into the dermal site, racemic SC-41930, (+)-SC-41930, and (-)-SC-41930 each inhibited granulocyte accumulation with ED50 values of 340 ± 30, 98 ± 5.7, and 1000 ± 142 ng, respectively; when given intravenously inhibited with ED50 values of 0.5 ± 0.06, 0.3 ± 0.04, and 1.4 ± 0.19 mg/kg, respectively; and when given intragastrically inhibited with ED50 values of 1.7 ± 0.20, 1.4 ± 0.23, and 3.0 ± 0.41 mg/kg, respectively. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040605
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    Stereoselective binding and activity of oxotremorine analogs at muscarinic receptors in rat brain (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 463-468 
    Details
    ISSN: 0899-0042
    Keywords: muscarinic receptors ; oxotremorine derivatives ; stereoselectivity ; adenylyl cyclase ; phosphoinositide metabolism ; receptor autoradiography ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The activities of the enantiomers of BM-5 were examined to measure muscarinic cholinergic selectivity in the central nervous system. Autoradiographic studies assessed the ability of each enantiomer to inhibit the binding of [3H]-(R)-quinuclidinyl benzilate ([3H]-(R)-QNB) to muscarinic receptors in the rat brain. (+)-(R)-BM-5 inhibited [3H]-(R)-QNB binding to rat brain sections at concentrations below 1.0 μM, while 100-fold higher concentrations of ( - )-(S)-BM-5 were required for comparable levels of inhibition. Analysis of the autoradiograms indicated that both stereoisomers had a similar distribution of high affinity binding sites. Each enantiomer displayed higher affinity for muscarinic receptors in the superior colliculi and lower affinity for receptors in the cerebral cortex and hippocampus. (+)-(R)-BM-5 and oxotremorine inhibited adenylyl cyclase activity in the cerebral cortex with efficacies comparable to that for acetylcholine. (+)-(R)-BM-5 was 26-fold more potent than ( - )-(S)-BM-5 in inhibiting adenylyl cyclase. Oxotremorine-M and carbamylcholine stimulated phosphoinositide turnover in the cerebral cortex. Oxotremorine had lower activity and (+)-(R)-BM-5 was essentially inactive at comparable concentrations. The difference in activity of the two enantiomers indicates a remarkable stereochemical selectivity for muscarinic receptors. The stereoselectivity index is comparable for both the autoradiographic assays (48) and measures of adenylyl cyclase activity (26) in the cerebral cortex. © 1992 Wiley-Liss, Inc.
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    Measurement of the (R)- and (S)-isomers of warfarin in patients undergoing anticoagulant therapy (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 488-493 
    Details
    ISSN: 0899-0042
    Keywords: achiral/chiral coupled HPLC ; α1-acid glycoprotein column ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An achiral/chiral high-performance liquid chromatographic system for the analysis of total warfarin together with the (R)- and (S)-enantiomers in clinical samples has been developed. The achiral analysis is achieved using a C8 column, which is coupled to a chiral stationary phase, α1-acid glycoprotein (AGP), thereby allowing for analysis of warfarin isomers without interfering serum peaks. A 0.015 M phosphate buffer mobile phase with 15% v/v propan-2-ol (pH 7.0) was used on the C8/AGP system. UV analysis at 308 nm was used for quantitation of total warfarin on the C8 column and fluorescence (excitation 300 nm, emission 390 nm) detection was employed for isomer quantitation on the AGP. Retention time of total warfarin on the C8 column was 5.95 min, while that of the (S)- and (R)-warfarin on the AGP column was 10.38 and 12.69 min, respectively. Peak resolution of the warfarin isomers was 1.64. All serum samples were subjected to solid-phase extraction. Data from two patients in a single dose study indicate that a two-compartmental model could represent the warfarin concentration - time data with enterohepatic circulation. In some patients studied during steady state therapy, concentrations of (S)-warfarin were greater than (R)-warfarin indicating that the clearance of the former is slower in these patients. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040806
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    Announcement (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 521-521 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040811
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    Resolution and stability of oxazepam enantiomers (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 443-446 
    Details
    ISSN: 0899-0042
    Keywords: oxazepam ; chiral stationary phases ; high-performance liquid chromatography ; enantiomer separation ; enantiomer stability ; racemization ; kinetics of racemization ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A solvent mixture containing dioxane, acetonitrile, and hexane was found to be suitable as a mobile phase to resolve oxazepam enantiomers by chiral stationary phase high performance liquid chromatography using covalent Pirkle columns. The resolved oxazepam enantiomers in this solvent mixture had a racemization half-life greater than 3 days at 23°C. When desiccated at 0°C as dried residue, OX enantiomers were stable for at least 50 days with less than 2% racemization. The conditions which stabilized OX enantiomers significantly facilitated the determination of racemization half-lives of OX enantiomers in a variety of aqueous and nonaqueous solvents and at different temperatures. © 1992 Wiley-Liss, Inc.
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    Masthead (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992) 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040801
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    Cytochrome p-455 nm complex formation in the metabolism of phenylalkylamines. XII. Enantioselectivity and temperature dependence in microsomes and reconstituted cytochrome p-450 systems from rat liver (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 469-477 
    Details
    ISSN: 0899-0042
    Keywords: metabolic intermediate (MI) complex ; amphetamine ; 1-phenyl-2-pentanamine ; N-hydroxyamphetamine ; 2-nitroso-1-phenylpropane ; P450 2B1 ; P450 2C11 ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Formation of metabolic intermediate (MI) complexes was studied with the enantiomers of amphetamine, 1-phenyl-2-pentanamine, N-hydroxyamphetamine, and 2-nitroso-1-phenylpropane (the C-nitroso analogue of amphetamine). Three different enzyme systems were used; liver microsomes from phenobarbital pretreated rats and two reconstituted systems containing the P450 2B1 and P450 2C11 forms of cytochrome P-450. Enantioselective complex formation in microsomes was shown for the amines and the nitroso compound, but not for the hydroxylamine. The highly purified P450 2B1 system formed the MI complex with all substrates tested, and the enantioselectivity observed with the microsomal system was reproduced. In the P450 2C11 system the nitroso compounds were completely inactive, whereas the enantiomers of N-hydroxyamphetamine still produced the complex at a high rate. Changes in temperature were shown to affect (R)-2-nitroso-1-phenylpropane more than its enantiomer. Both enantiomers showed biphasic Arrhenius plots for MI complex formation in microsomes (breaks around 22°C), but the activation energies of the (R)-isomer were about five times higher than those of the (S)-isomer. A theory is presented which suggests different modes of interaction with the active site of P-450 to account for the different behaviour of the various substrates. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/chir.530040803
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    Electronic Resource
    Masthead (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992) 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040101
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  • 94
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    Stereoselective aliphatic hydroxylation of 6-n-propylchromone-2-carboxylic acid by female Dutch rabbits (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 1-7 
    Details
    ISSN: 0899-0042
    Keywords: product enantioselectivity ; aliphatic hydroxylation ; 6-n-propylchromone carboxylic acid ; chiral HPLC ; chiral shift 1H-NMR ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 6-n-Alkylchromone-2-carboxylic acids are metabolized solely by aliphatic oxidation. In the rabbit, the 6-n-propyl congener (PCCA) undergoes ω-1 hydroxylation exclusively. Following administration of PCCA to female Dutch rabbits (500 μmol/kg), some 77% of the dose was excreted in the urine, 41% as PCCA and 36% as 6-(2'-hydroxy-n-propyl)chromone-2-carboxylic acid. Since this metabolite is chiral, we have examined the stereochemistry of the excreted material. Diastereoisomeric (as camphanate and α-methoxy-α-(trifluoromethyl)phenylacetate esters) and direct chiral HPLC and chiral lanthanide shift NMR have each shown the S:R ratio of the excreted metabolite to be 76:24. When rabbits were dosed with the racemic metabolite, excretion of the compound was not stereoselective. The regio- and stereo-selectivity of the aliphatic hydroxylation of PCCA are thus reflections of the selectivities of the enzyme systems responsible for its formation and suggest PCCA to be an appropriate probe compound for the study of prochiral-chiral hydroxylations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040103
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  • 95
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    Enantiospecificity of kappa receptors: Comparison of racemic compounds and active enantiomers in two novel series of kappa agonist analgesics (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 8-15 
    Details
    ISSN: 0899-0042
    Keywords: opioids ; piperidines ; 1,2,3,4-tetrahydroisoquinolines ; antinociception ; binding affinity ; QSAR ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two novel series, Ia,b and IIa,b, of kappa opioid antinociceptive agents have recently been described. 2a,b,3a,b,c The biological activities of 16 racemic compounds and their corresponding (-) enantiomers are now compared in a battery of tests. Enantiomers of unsubstituted piperidines Ia were synthesized starting from S(-) pipecolic acid, whereas the enantiomerically pure substituted piperidines (Ib), tetrahydroisoquinolines (IIa), and thienopiperidines (IIb) were, in general, obtained after diastereomeric crystallization of the corresponding tartrate salts. The absolute stereochemistry of one representative enantiomer from series IIa was determined to be (1S) by X-ray crystallographic analysis. Antinociceptive activity in the mouse abdominal constriction and tail-flick tests following subcutaneous administration, and binding affinity for κ and μ receptors, were found to reside predominantly in the (-) enantiomers. Consequently, racemic compounds showed approximately half potency of the corresponding enantiomers. This potency difference was less clear after oral administration presumably due to small differences in bioavailability of the two corresponding enantiomers.For compounds with some affinity also for μ receptors (Ki 〈1,000 nM), the κ/μ selectivity was maintained within each enantiomeric pair, in contrast to results found for other κ agonists.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040104
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  • 96
    Electronic Resource
    Electronic Resource
    Chiral discriminations with cinchona alkaloids (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 43-49 
    Details
    ISSN: 0899-0042
    Keywords: chiral discrimination ; enantiomeric separation ; chiral solvating agents ; asymmetric synthesis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040110
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  • 97
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    Enantioselective chromatography of the antimalarial agents chloroquine, mefloquine, and enpiroline on a α1 -acid glycoprotein chiral stationary phase: Evidence for a multiple-site chiral recognition mechanism (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 30-35 
    Details
    ISSN: 0899-0042
    Keywords: chiral liquid chromatography ; α1 -acid glycoprotein ; antimalarial agents ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of mobile phase pH and dimethyloctylamine (DMOA) on the retention (k') and stereoselectivity (α) of antimalarial agents mefloquine, enpiroline, and chloroquine on the α1-acid glycoprotein chiral stationary phase (AGP-CSP) was investigated. An increase of k' with increasing pH was observed while the effect on α was a function of the solute. The magnitude and direction of changes induced by DMOA depended on pH and the structure of the solute.The results of this study are consistent with a change of the conformation of the AGP between pH 5 and 7. At pH 7, the effect of DMOA on mefloquine was relatively well described by a competitive displacement from one enantioselective site. The effect on chloroquine and enpiroline suggests a multiple-site mechanism in which both competitive and allosteric interactions are involved.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040108
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  • 98
    Electronic Resource
    Electronic Resource
    Preparation of α-substituted α-amino acids of high enantiomeric purity (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 302-307 
    Details
    ISSN: 0899-0042
    Keywords: hydantoin derivatives ; chiral isocyanates ; LC separation of diastereomers ; preparative LC separation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Racemic 5,5-dialkyl hydantoins derived from ketones are resolved by preparative liquid chromatography as the diastereomeric 1-carboxamide derivatives afforded by the reaction with optically pure configurationally known α-phenylethyl isocyanate. Hydrolysis of the resolved diastereomers affords α-substituted α-amino acids of high enantiomeric purity. The synthetic route is short, overall yields are high, and the absolute configuration of the amino acid enantiomers may be deduced from the chromatographic and NMR properties of the diastereomers. © 1992 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040508
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  • 99
    Electronic Resource
    Electronic Resource
    Application of antibody-mediated extraction for the stereoselective determination of the active metabolite of loxoprofen in human and rat plasma (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 308-315 
    Details
    ISSN: 0899-0042
    Keywords: loxoprofen ; 2-arylpropionic acid ; active metabolite ; immobilized antibody column ; chiral hapten ; diastereomeric derivatization ; chiral inversion ; stereoselective ketone reduction ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Antibody-mediated extraction followed by chiral high-performance liquid chromatography (HPLC) was applied to stereoselective determination in human and rat plasma of the active metabolite [(2S,1]R,2[S)-trans-alcohol] with three chiral centers of Loxoprofen, a 2-arylpropionic acid antiinflammatory agent after oral administration. Antiserum against the (1'R,2'S)-cyclopentanol moiety was obtained from a rabbit immunized with bovine serum albumin conjugate linked to the propionic acid moiety, in which another chiral center is located. Then, the immunoglobulin G purified by a protein A column was coupled to BrCN-activated Sepharose 4B. Plasma samples were applied to the immobilized antibody column. After washing the column to remove unrequired stereoisomers, a mixture of two diastereomers whose configurations were 1'R,2'S in the cyclopentanol moiety was extracted with 95% methanol. The solvent was evaporated and the residue was derivatized with (+)-(R)-1-(1-naphthyl)ethylamine as a chiral reagent to separate the diastereomers by HPLC. This combined analytical method showed the stereoselective metabolism of Loxoprofen in human, that is, 64% of the total amount of four trans-alcohol stereoisomers was in the 2S, 1'R,2'S form, which is the active metabolite. This phenomenon was also observed in rats given Loxoprofen and its (2S)- and (2R)-isomers, and is explained by stereoselective ketone reduction of Loxoprofen to the (1'R,2'S)-trans-alcohol and inversion from 2R to 2S in the propionic acid moiety. Antibody-mediated extraction should be a selective and simple clean-up method for determining haptens with complicated structures, combined with an appropriate analytical method. © 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040509
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  • 100
    Electronic Resource
    Electronic Resource
    Editorial (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. i 
    Details
    ISSN: 0899-0042
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040102
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