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  • 1
    Electronic Resource
    Electronic Resource
    Properties of Alkyl and Aryl-ψ-oxatriazoles1 (1956)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 78 (1956), S. 5124-5125 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01600a082
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  • 2
    Electronic Resource
    Electronic Resource
    Response of antioxidative enzymes to plum pox virus in two apricot cultivars (2001)
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 111 (2001), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Recent evidence has indicated that activated oxygen species (AOS) may function as molecular signals in the induction of defence genes. 
In the present work, the response of antioxidative enzymes to the plum pox virus (PPV) was examined in two apricot (Prunus armeniaca L.) cultivars, which behaved differently against PPV infection. In the inoculated resistant cultivar (Goldrich), a decrease in catalase (CAT) as well as an increase in total superoxide dismutase (SOD) and dehydroascorbate reductase (DHAR) activities were observed. Ascorbate peroxidase (APX), glutathione reductase (GR) and monodehydroascorbate reductase (MDHAR) did not change significantly in relation to non-inoculated (control) plants. In the susceptible cultivar (Real Fino), inoculation with PPV brought about a decrease in CAT, SOD and GR, whereas a rise in APX, MDHAR and DHAR activities was found in comparison to non-inoculated (control) plants. 
Apricot leaves contain only CuZn-SOD isozymes, which responded differently to PPV depending on the cultivar. Goldrich leaves contained 6 SODs and both SOD 1 and SOD 2 increased in the inoculated plants. In leaves from Real Fino, 5 SODs were detected and only SOD 5 was increased in inoculated plants. 
The different behaviour of SODs (H2O2-generating enzymes) and APX (an H2O2-remover enzyme) in both cultivars suggests an important role for H2O2 in the response to PPV of the resistant cultivar, in which no change in APX activity was observed. This result also points to further studies in order to determine if an alternative H2O2-scavenging mechanism takes place in the resistant apricot cultivar exposed to PPV. On the other hand, the ability of the inoculated resistant cultivar to induce SOD 1 and SOD 2 as well as the important increase of DHAR seems to suggest a relationship between these activities and resistance to PPV. 
This is the first report about the effect of PPV infection on the antioxidative enzymes of apricot plants. It opens the way for the further studies, which are necessary for a better understanding of the role of antioxidative processes in viral infection by PPV in apricot plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2001.1110308.x
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  • 3
    Electronic Resource
    Electronic Resource
    Tolerance of pea (Pisum sativum L.) to long-term salt stress is associated with induction of antioxidant defences (2000)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 23 (2000), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Using two cultivars of Pisum sativum L. with different sensitivity to NaCl, the effect of long-term (15 d) NaCl (70 m M) treatments on the activity and expression of the foliar ascorbate–glutathione cycle enzymes, superoxide dismutase isozymes and their mRNAs was evaluated and related to their ascorbate and glutathione contents. High-speed supernatant (soluble) fractions, enriched for cytosolic components of the antioxidant system, were used. In this fraction from the NaCl-tolerant variety (cv Granada), the activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), Mn-superoxide dismutase (Mn-SOD) and dehydroascorbate reductase (DHAR) increased, while CuZn-SOD activity remained constant. In the NaCl-sensitive plants (cv Challis), salinity did not produce significant changes in APX, MDHAR and GR activities. Only DHAR activity was induced in cv Challis, whereas soluble CuZn-SOD activity decreased by about 35%. Total ascorbate and glutathione contents decreased in both cultivars, but the decline was greater in NaCl-sensitive plants. This difference between the two cultivars was more pronounced when the transcript levels of some these enzymes were examined. Transcript levels for mitochondrial Mn-SOD, chloroplastic CuZn-SOD and phospholipid hydroperoxide glutathione peroxidase (PHGPX), cytosolic GR and APX were strongly induced in the NaCl-tolerant variety but not in the NaCl-sensitive variety. These data strongly suggest that induction of antioxidant defences is at least one component of the tolerance mechanism of peas to long-term salt-stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.2000.00602.x
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  • 4
    Electronic Resource
    Electronic Resource
    Existence of Half-salt Cations in Aqueous Solutions of Aminophenols (1965)
    [s.l.] : Nature Publishing Group
    Nature 207 (1965), S. 1385-1386 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Aminophenols were shown to be ampholytes with no zwitterion structure1, and therefore the following two dissociation stages can be distinguished a priori in their aqueous solutions: B+IL+ B ^ (1) (2) where B represents a neutral aminophenol molecule, B+ the ammonium cation and B~ ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/2071385a0
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  • 5
    Electronic Resource
    Electronic Resource
    Antioxidant enzyme activities in shoots from three mycorrhizal shrub species afforested in a degraded semi-arid soil (2003)
    Oxford, UK : Munksgaard International Publishers
    Physiologia plantarum 118 (2003), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Mycorrhizae may help plants to thrive in Mediterranean semi-arid ecosystems by altering antioxidant enzyme activities. Our objective was to determine the influence of mycorrhizal inoculation with an allochthonous arbuscular mycorrhizal (AM) fungus, Glomus claroideum, Schenck & Smith, or with a mixture of native AM fungi, on the activity of antioxidant enzymes from shoots of Olea europaea L. ssp. sylvestris, Retama sphaerocarpa (L.) Boissier and Rhamnus lycioides L. seedlings afforested in a degraded Mediterranean semi-arid soil. One year after planting, shoot biomass of inoculated O. europaea seedlings was about 630%, of non-inoculated plants. Shoot biomass of G. claroideum-colonized R. sphaerocarpa was greater than that of seedlings inoculated with the mixed native AM fungi after 12 months. Inoculation with a mix of native AM fungi was the most effective treatment for increasing shoot biomass and N, P and K contents in shoot tissues of R. lycioides. Both mycorrhizal inoculation treatments increased the nutrient contents in shoots of O. europaea and R. lycioides. In O. europaea plants, the inoculation treatments increased catalase, ascorbate peroxidase and dehydroascorbate reductase activities, but not monodehydroascorbate reductase and glutathione reductase activities. Inoculation with G. claroideum increased the activities of all antioxidant enzymes in R. sphaerocarpa. Monodehydroascorbate reductase, glutathione reductase and superoxide dismutase activities in R. lycioides leaves were preferentially increased by inoculation with the mixture of native AM fungi. This work support the view that increased antioxidant enzyme activities could be involved, at least in part, in the beneficial effects of mycorrhizal colonization on the performance of shrub species grown under semi-arid Mediterranean conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2003.00149.x
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  • 6
    Electronic Resource
    Electronic Resource
    Mitochondrial and peroxisomal ascorbate peroxidase of pea leaves (1998)
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 104 (1998), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The isoenzyme pattern and the substrate specificity of the membrane-bound mitochondrial and peroxisomal ascorbate peroxidases (APX; EC 1.11.1.11) from pea leaves are studied. The substrate specificity of both APXs was assayed using the electron donors ascorbate and pyrogallol, whereas o-dianisidine, hydroquinone, tetramethylbenzidine and 4-methoxy-α-naphthol were also assayed with mitochondrial APX (mitAPX). In leaf mitochondria, the specific activity of APX was similar with pyrogallol and ascorbate, the activity being inhibited by p-CMS. mitAPX showed low activity with the guaiacol peroxidase (GPX)-type substrates, tetramethylbenzidine and 4-methoxy-α-naphthol. Activity of mitAPX with hydroquinone suggest a potential role of mitAPX in the drainage of electrons from the mitochondrial electron chain at the level of ubiquinone. In peroxisomes, the APX (perAPX) specific activity was much higher with pyrogallol than with ascorbate. This perAPX was more sensitive to incubation with Triton X-100 than the mitAPX. By native PAGE the mitAPX was resolved in 6 isoenzyme bands, and the activity of the 3 main bands (mitAPX III, III′ and IV) was inhibited by p-CMS. These 3 major isozymes were also present in mitochondrial membrane fractions. Staining for GPX activity with 4-methoxy-α-naphthol revealed that the APX detected in mitochondria did not have the capacity to oxidize 4-MN, and therefore cannot be considered as true GPX. When intact peroxisomes and peroxisomal membranes were subjected to native PAGE, no APX activity could be detected and this was probably due to the inactivation of perAPX. Results obtained suggest that pea mitochondrial APX (mitAPX) represent a distinct and novel isozyme different from those APXs of chloroplast and cytosolic origin previously reported. The peroxisomal APX (perAPX), however, appears to ressemble the chloroplast APXs as regards its sensitivity to Triton X-100.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.1998.1040424.x
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  • 7
    Electronic Resource
    Electronic Resource
    Theoretical interstellar and prebiotic organic chemistry: A tentative methodology (1976)
    Springer
    Origins of life and evolution of the biospheres 7 (1976), S. 163-173 
    Details
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract A theoretical methodology for the systematic study of the interstellar molecules is proposed. Some examples, dealing with formaldehyde excited states, formyl radical and ion, reactivity of the excited states of formic acid, methyl cyanide and methyl acetylene, as well as the reaction path of formaldehyde photodecomposition are presented. Quantum chemical methods appear to be a powerful tool to study the structure and behaviour of molecules related with interstellar space and the Origin of Life.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00926933
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  • 8
    Electronic Resource
    Electronic Resource
    Bone changes in alcoholic liver cirrhosis (1988)
    Springer
    Digestive diseases and sciences 33 (1988), S. 1089-1095 
    Details
    ISSN: 1573-2568
    Keywords: undecalcified bone biopsy ; bone histomorphometry ; alcoholic hepatic cirrhosis ; osteoporosis ; hepatic osteodystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Bone biopsies of 52 histologically confirmed alcoholic cirrhotic patients and 15 age- and sex-matched controls have been histomorphometrically analyzed determining trabecular bone volume (TBV), mineralized bone volume (MBV), and osteoid volume (OV). We also determined serum PTH, 25-OH-D3, calcitonin, FSH, LH, estradiol, testosterone, T3 and T4, urine cortisol, routine liver function tests, serum and urinary calcium, phosphorus, and magnesium. We found a high prevalence of osteoporosis: TBV was significantly lower in cirrhotic patients (T=7.23, P〈0.001), 41 of them being in the range of osteoporosis; none of them had osteomalacia. Levels of all the above-mentioned hormones and electrolytes were almost normal, and no correlation was found between them and liver function tests, as occurred with the bone parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01535783
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  • 9
    Electronic Resource
    Electronic Resource
    Structure and expression of three genes encoding ACC oxidase homologs from melon (Cucumis melo L.) (1996)
    Springer
    Molecular genetics and genomics 251 (1996), S. 81-90 
    Details
    ISSN: 1617-4623
    Keywords: ACC oxidase ; Ethylene ; Multigene family ; Differential expression ; Cucumis melo L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The enzyme ACC oxidase catalyses the last step of ethylene biosynthesis in plants, converting 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. We have previously described the isolation and characterization of a cDNA clone (pMEL1) encoding an ACC oxidase homolog from melon (Cucumis melo L.). Here we report the isolation and characterization of three genomic clones, corresponding to three putative members of the ACC oxidase gene family in melon. All are transcriptionally active. The sequences of these genes have been determined. One genomic clone (CM-ACO1), corresponding to the cDNA previously isolated, presents a coding region interrupted by three introns. Its transcription initiation site has been defined with RNA from ripe fruit and ethylene-treated leaves. The other two genes (CM-ACO2, CM-ACO3) have only two introns, at positions identical to their counterparts inCM-ACO1. The degree of DNA homology in the coding regions ofCM-ACO2 andCM-ACO3 relative toCM-ACO1 is 59% and 75%, respectively.CM-ACO2 andCM-ACO3 are 59% homologous in their coding regions. These three genes have close homology toPH-ACO3, a member of the ACC oxidase multigene family of petunia. The predicted amino acid sequences of CM-ACO1 and CM-ACO3 are 77% to 81% identical to those encoded by the tomato and petunia genes, while the deduced amino acid sequence ofCM-ACO2 shows only 42% to 45% homology. RT-PCR analysis using gene-specific primers shows that the three genes are differentially expressed during development, ethylene treatment and wounding.CM-ACO1 is induced in ripe fruit and in response to wounding and to ethylene treatment in leaves.CM-ACO2 is detectable at low level in etiolated hypocotyls.CM-ACO3 is expressed in flowers and is not induced by any of the stimuli tested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02174348
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  • 10
    Electronic Resource
    Electronic Resource
    Differential activation of two ACC oxidase gene promoters from melon during plant development and in response to pathogen attack (1997)
    Springer
    Molecular genetics and genomics 256 (1997), S. 211-222 
    Details
    ISSN: 1617-4623
    Keywords: Key words ACC oxidase ; Ethylene ; Hypersensitive ; Response ; Senescence ; Transcriptional activation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract ACC (1-aminocyclopropane-1-carboxylate) oxidase genes are differentially expressed in melon during development and in response to various stresses. We investigated the molecular basis of their transcription by analyzing the 5′ untranslated regions of the ACC oxidase genes CM-ACO1 and CM-ACO3. In order to determine how their temporal and spatial expression patterns were established, we fused the promoter regions of CM-ACO1 (726 bp) and CM-ACO3 (2260 bp) to the β-glucuronidase (GUS) reporter gene and examined their regulation in transgenic tobacco plants. The CM-ACO1 promoter was able to drive GUS expression in response to wounding, and to treatment with ethylene or copper sulfate. It was also rapidly induced (8–12 h post-inoculation) in tobacco leaves inoculated with the hypersensitive response (HR)-inducing bacterium Ralstonia solanacearum. Expression was also observed during compatible interactions but was delayed. In contrast, the CM-ACO3 promoter was not expressed in response to infection, but was up-regulated during flower development. Both promoters were regulated during leaf senescence but in different patterns. The CM-ACO1-driven GUS activity increased sharply concomitantly with the onset of chlorophyll breakdown, while the CM-ACO3 promoter drove strong GUS expression in green, fully expanded leaves and this declined at the onset of senescence. This result is consistent with the expression patterns of these two genes in senescent melon leaves. These data suggest that the regulation of expression of CM-ACO1 is related preferentially to stress responses, whereas CM-ACO3 seems to be associated with developmental processes. The possible role of ethylene is discussed, particularly in the regulation of the CM-ACO1 gene in response to stress and during senescence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380050563
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