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1.
Growth of Chlorella vulgaris and Prototheca zopfii is inhibited by treatment with 3-amino-1,2,4-triazole. Growth of these 2 algae in the presence of amino triazole is accompanied by the accumulation in the culture media of the dephosphorylated histidine precursor, imidazoleglycerol. The addition of histidine to the culture media in the presence of amino triazole restored the normal growth rates of these organisms and reduced the accumulation of imidazoleglycerol. These data suggest that amino triazole inhibits the synthesis of histidine by interfering with the activity of the enzyme, imidazoleglycerol phosphate dehydrase. 相似文献
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Changes in the soluble nitrogen compounds after application of 3-amino-1,2,4-triazole (amitrole) to amitrole susceptible and amitrole resistant ecotypes of Cirsium arvense were investigated. One day after treatment with amitrole the concentration of all nitrogen compounds tested in the leaves of the susceptible ecotype was reduced, but none was eliminated. Five days after treatment the concentration of the same compounds increased in the leaves above the control (0 amitrole) concentration. The resistant ecotype had less change in nitrogen compounds than did the susceptible ecotype. Changes in the soluble nitrogen compounds in the stem and root fraction were less than in the leaf fraction. The authors suggest a two phase reaction of the soluble nitrogen compounds due to amitrole treatment. It is concluded that the primary biochemical lesion of amirole in mature Cirsium arvense is not the elimination of glycine, serine, or any other soluble nitrogen compound. 相似文献
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The in Vivo and in Vitro Inhibition of Catalase from Leaves of Nicotiana sylvestris by 3-Amino-1,2,4-Triazole 总被引:3,自引:2,他引:1
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Havir EA 《Plant physiology》1992,99(2):533-537
Seedlings of tobacco (Nicotiana sylvestris) were treated in vivo with 0.03 to 20 millimolar 3-amino-1,2,4-triazole (aminotriazole). There was a rapid loss of catalase (EC 1.11.1.6) activity over the first 5 hours followed by a slower decrease for the next 4 hours to a level that was 15 to 20% of the initial activity, with little or no change for periods up to 3 days. Fifty percent loss of catalase activity occurred at 0.10 to 0.15 millimolar inhibitor (18-hour incubation). The isozymes of tobacco catalase differed in sensitivity to the inhibitor. Enhanced-peroxidatic catalase (EP-CAT) (Havir EA, McHale NA, [1989] Plant Physiol 91: 812-815) decreased 35% under conditions in which the major isozyme decreased 85%. The resistance to aminotriazole inhibition demonstrated in vivo by EP-CAT was also observed in vitro. The times for 50% inhibition at 0.67, 3.33, 5.0, 10.0, and 15 millimolar aminotriazole were 15, 5, 2.6, 2.5, and 1.5 minutes, respectively, for the major isozyme of catalase and 60, 18.5, 5.1, 4, and 3.0 minutes, respectively, for EP-CAT. Increasing H2O2 concentration did not change the sensitivity of EP-CAT to aminotriazole. The major form of catalase contained 4.0 ± 0.4 moles of heme per mole enzyme and EP-CAT 3.4 ± 0.3. Thus, the resistance of EP-CAT to aminotriazole is probably not due to lowered affinity for H2O2 or alteration in heme content but to structural changes that impair inhibitor binding. 相似文献
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The present study was performed to see the physiological role of cytosolic ascorbate peroxidase (APX) and its relationship
to other enzymes involved in the H2O2 scavenging metabolism, and also to elucidate the regulation of APX expression in dark-grown radish (Raphanus sativus L. cv Taiwang) cotyledons. To do so, 3-amino-l,2,4-triazole (aminotriazole), a known specific inhibitor of catalase, was
used to simulate a catalase-deficient phenomenon in cotyledons. Aminotriazole, in very low concetration (10-4 M), inhibited remarkably the development of catalase activity in cotyledons during dark germination. This inhibition of catalase
by aminotriazole, however, did not result in any significant changes in the growth response and the H2O2 level of developing cotyledons. In addition, the development of guaiacol peroxidase (GPX) activity was also not significantly
affected. Unlike GPX, cytosolic APX activity was induced rapidly and reached a 1.7-fold increase in aminotriazole treated
cotyledons at day 7 after germination. However,in vitro incubation of cytosolic APX preparation from cotyledons with aminotriazole did not result in any significant change in activity.
One cytosolic APX isozyme (APXa) band involved in this APX activation was predominantly intensified in a native polyacrylamide
gel by activity staining assay. This means that this APXa isozyme seems to play a key role in the expression of cytosolic
APX activity. On the other hand, 2-day-old control seedlings treated with exogenous 1 mM H2O2 for 1 h showed a significant increase of cytosolic APX acitivity even in the absence of aminotriazole. Also, 2 μM cycloheximide
treatment substantially inhibited the increase of APX activity due to aminotriazole. Based on these results, we suggest that
a radish cytosolic APX could probably be substituted for catalase in H2O2 removal and that the expression of APX seems to be regulated by a change of endogenous H2O2 level which couples to APX protein synthesis in a translation stage in cotyledons. 相似文献
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The behaviour of amitrole (3-amino-l,2,4-triazole) in 3-year old seedlings of Pinus ponderosa (ponderosa pine) and Abies concolor (white fir) is described. Visual symptoms of amitrole action appeared as a chlorosis of young needles, the extent of which varied with time and species. Maximum chlorosis was obtained when the application was made during the stage when no visible growth occurred. The greater susceptibility of ponderosa pine seedlings could be accounted for by the lower resistance to uptake of the herbicide into the needles and not by any difference between the conifer species in the metabolism of amitrole. The translocation and metabolism of amitrole in the two conifer species are discussed. In both of the conifer species amitrole was converted into three metabolic products two of which were found to be identical with the previously described Unknown I and II. Two types of treatment, on exposed phloem and on the needles, provided the possibility for a direct study of the site of amitrole metabolism. This site appeared to be in the stem. Amitrole was the mobile, toxic compound in both species and was translocated in both symplast and apoplast. A circulation of the herbicide in the plant was observed. From the phloem amitrole diffused relatively slowly into the xylem, and during this lateral translocation part of the amitrole was metabolized. The rate of this detoxification process seemed to be dependent upon how fast amitrole moved from phloem to xylem and vice versa. This rate seemed to show a positive correlation with the intensity of the cambial activity. The translocation of amitrole to the roots was greatest when no visible growth could be detected. 相似文献
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Annalisa Facchini Silvia Cetrullo Stefania D'Adamo Serena Guidotti Manuela Minguzzi Andrea Facchini Rosa Maria Borzì Flavio Flamigni 《PloS one》2014,9(10)
Hydroxytyrosol (HT), a phenolic compound mainly derived from olives, has been proposed as a nutraceutical useful in prevention or treatment of degenerative diseases. In the present study we have evaluated the ability of HT to counteract the appearance of osteoarthritis (OA) features in human chondrocytes. Pre-treatment of monolayer cultures of chondrocytes with HT was effective in preventing accumulation of reactive oxidant species (ROS), DNA damage and cell death induced by H2O2 exposure, as well as the increase in the mRNA level of pro-inflammatory, matrix-degrading and hypertrophy marker genes, such as iNOS, COX-2, MMP-13, RUNX-2 and VEGF. HT alone slightly enhanced ROS production, but did not enhance cell damage and death or the expression of OA-related genes. Moreover HT was tested in an in vitro model of OA, i.e. three-dimensional micromass cultures of chondrocytes stimulated with growth-related oncogene α (GROα), a chemokine involved in OA pathogenesis and known to promote hypertrophy and terminal differentiation of chondrocytes. In micromass constructs, HT pre-treatment inhibited the increases in caspase activity and the level of the messengers for iNOS, COX-2, MMP-13, RUNX-2 and VEGF elicited by GROα. In addition, HT significantly increased the level of SIRT-1 mRNA in the presence of GROα. In conclusion, the present study shows that HT reduces oxidative stress and damage, exerts pro-survival and anti-apoptotic actions and favourably influences the expression of critical OA-related genes in human chondrocytes treated with stressors promoting OA-like features. 相似文献
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Reactive oxygen species such as hydrogen peroxide have the potential to alter metabolic rates of marine prokaryotes, ultimately impacting the cycling and bioavailability of nutrients and carbon. We studied the influence of H2O2 on prokaryotic heterotrophic production (PHP) and extracellular enzymatic activities (i.e., β-glucosidase [BGase], leucine aminopeptidase [LAPase] and alkaline phosphatase [APase]) in the subtropical Atlantic. With increasing concentrations of H2O2 in the range of 100–1000 nM, LAPase, APase and BGase were reduced by up to 11, 23 and 62%, respectively, in the different water layers. Incubation experiments with subsurface waters revealed a strong inhibition of all measured enzymatic activities upon H2O2 amendments in the range of 10–500 nM after 24 h. H2O2 additions also reduced prokaryotic heterotrophic production by 36–100% compared to the rapid increases in production rates occurring in the unamended controls. Our results indicate that oxidative stress caused by H2O2 affects prokaryotic growth and hydrolysis of specific components of the organic matter pool. Thus, we suggest that oxidative stress may have important consequences on marine carbon and energy fluxes. 相似文献
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离体蒜苔构成一个完整的细胞内含物再分配系统。 25 ℃条件下,于黑暗中贮存时,苔茎基部细胞内含物转移到顶端珠蒜中,最后苔茎下部枯萎,顶端形成鲜嫩多汁的珠蒜。适当浓度 GA3处理苔茎基部可以有效抑制上述细胞内含物再分配过程。已有研究表明, H2O2由超氧化物歧化酶(SOD)催化产生,被过氧化物酶(POD)和过氧化氢酶(CAT)催化降解; H2O2对生物个体发育具有重要调节作用。本文主要测定GA3对离体蒜苔H2O2代谢的影响;为进一步探讨H2O2在细胞内含物再分配中的作用提供参考。 取珠蒜未明显膨大的离体蒜苔为供试材料,采用 50μg/mL GA3溶液处理蒜苔基部,用比色法和氧电极法测定珠蒜和苔茎下部H2O2水平和SOD、POD、CAT活性。结果表明:(1)在处理后48h内,珠蒜和苔茎下部H2O2代谢即产生明显差异(Fig.1-4);(2)贮存20d后对照珠蒜明显膨大,而GA3处理珠蒜光显著变化(Table1);(3)GA3处理显著提高了珠蒜H2O2水平和SOD、POD、CAT活性,相反苔茎下部H2O2水平和POD、CAT活性受到显著抑制,而SOD活性提高(Fig.5-8)。GA3处理对珠蒜和苔茎下部H2O2代谢的相反 相似文献
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Girish B. Chheda Henry A. Tworek Arvind K. Bhargava Elliot Rachlin Shib P. Dutta Helen B. Patrzyc 《Nucleosides, nucleotides & nucleic acids》2013,32(4):417-429
Abstract A new modified nucleoside, 3-(3-amino-3-carboxypropyl)-uridine was isolated from a 24 hour collection of a normal human urine. The structure was assigned on the basis of UV, NMR and mass spectrometry data and confirmed by comparison of the spectral data and HPLC mobilities with those of an authentic sample. Origin and significance of this nucleoside in relation to tRNA is discussed. The new nucleoside is present also in the urine of cancer patients but in smaller amounts. 相似文献
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Anaerobic Metabolism of 1-Amino-2-Naphthol-Based Azo Dyes (Sudan Dyes) by Human Intestinal Microflora
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Haiyan Xu Thomas M. Heinze Siwei Chen Carl E. Cerniglia Huizhong Chen 《Applied microbiology》2007,73(23):7759-7762
The rates of metabolism of Sudan I and II and Para Red by human intestinal microflora were high compared to those of Sudan III and IV under anaerobic conditions. Metabolites of the dyes were identified as aniline, 2,4-dimethylaniline, o-toluidine, and 4-nitroaniline through high-performance liquid chromatography and liquid chromatography electrospray ionization tandem mass spectrometry analyses. These data indicate that human intestinal bacteria are able to reduce Sudan dyes to form potentially carcinogenic aromatic amines. 相似文献
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Some Enzymes of Hydrogen Peroxide Metabolism in Leaves and Root Nodules of Medicago sativa 总被引:7,自引:0,他引:7
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Leaves and nodules (bacteroids and cytosol) of alfalfa (Medicago sativa L. cv Aragon) plants inoculated with Rhizobium meliloti strain 102F51 have been analyzed for the presence of the enzymes superoxide dismutase (SOD, EC 1.15.1.1), catalase (EC 1.11.1.6), and peroxidase (EC 1.11.1.7). All three fractions investigated (leaves, bacteroids, and nodular cytosol) show Cu,Zn-SOD activity. Besides, the bacteroids and cytosol of nodules possess CN−-insensitive SOD activities. Studies of SOD inactivation with H2O2 indicate that, very likely, a Mn-SOD is present in the bacteroids, and suggest that the cytosol contain both Mn-SOD and Fe-SOD. Bacteroids show high catalase activity but lack peroxidase. By contrast, the nodule cytosol exhibits an elevated peroxidase activity as compared with the foliar tissue; this activity was completely inhibited by 50 to 100 micromolar KCN. The significantly lower contents of H2O2 and malondialdehyde (a product of lipid peroxidation) in nodules with respect to those in leaves reveal that the above-mentioned bacteroid and cytosol enzymes act in an efficient and combined manner to preserve integrity of nodule cell membranes and to keep leghemoglobin active. 相似文献
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Justine M. Tishinsky David W.L. Ma Lindsay E. Robinson 《Obesity (Silver Spring, Md.)》2011,19(2):262-268
Adiponectin, an anti‐inflammatory and insulin‐sensitizing protein secreted from adipose tissue, may be modulated by dietary fatty acids, although the mechanism is not fully known. Our objective was to investigate the effect of long‐chain n‐3 polyunsaturated fatty acids (PUFAs) on adiponectin in cultured human adipocytes, and to elucidate the role of peroxisome proliferator‐activated receptor‐γ (PPARγ) in this regulation. Isolated human adipocytes were cultured for 48 h with 100 µmol/l eicosapentaenoic acid (C20:5n‐3, EPA), docosahexaenoic acid (C22:6n‐3, DHA), palmitic acid (C16:0), 100 µmol/l EPA plus 100 µmol/l DHA, or bovine serum albumin (control). Additionally, adipocytes were treated for 48 h with a PPARγ antagonist (BADGE) or agonist (rosiglitazone) in isolation or in conjunction with either EPA or DHA. At 48 h, EPA and DHA increased (P < 0.05) adiponectin secretion by 88 and 47%, respectively, while EPA, but not DHA, also increased (136%, P < 0.001) cellular adiponectin protein. Interestingly, PPARγ antagonism completely abolished the DHA‐mediated increase in secreted adiponectin, but only partially attenuated the EPA‐mediated response. Thus, EPA's effects on adiponectin do not appear to be entirely PPARγ mediated. Rosiglitazone increased (P < 0.001) the secreted and cellular adiponectin protein (90 and 582%, respectively). Finally, the effects of EPA and rosiglitazone on adiponectin secretion were additive (+230% at 48 h combined, compared to 121 and 124% by EPA or rosiglitazone alone, respectively). Overall, our findings emphasize the therapeutic importance of long‐chain n‐3 PUFA alone, or in combination with a PPARγ agonist, as a stimulator of adiponectin, a key adipokine involved in obesity and related diseases. 相似文献
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以唐古特白刺(Nitraria tangutorum Bobr.)愈伤组织为材料,研究外源H2O2(2和10 μmol·L-1)处理下其脯氨酸含量及相关代谢酶活性的变化,试图从细胞水平揭示H2O2影响脯氨酸代谢的生理机制。结果显示,2和10 μmol·L-1 H2O2处理24 h使唐古特白刺愈伤组织脯氨酸含量分别变为对照的112%和92%,而处理72 h后,脯氨酸含量增加为对照的141%和119%;与对照相比,外源H2O2处理诱导愈伤组织脯氨酸脱氢酶活性降低,而谷氨酸激酶活性升高,但鸟氨酸转氨酶活性无显著变化;此外,H2O2处理使唐古特白刺愈伤组织内源性H2O2含量升高。结果表明,外源H2O2诱导了唐古特白刺愈伤组织H2O2含量的增高和脯氨酸的积累,且H2O2处理下脯氨酸脱氢酶活性的降低及谷氨酸激酶的升高与愈伤组织脯氨酸的积累有关。 相似文献
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Formation of Hydrogen Peroxide by Group N Streptococci and Its Effect on Their Growth and Metabolism 总被引:19,自引:6,他引:13
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The formation of hydrogen peroxide by group N streptococci was found to occur through the action of a reduced nicotinamide adenine dinucleotide (NADH) oxidase which catalyzed the oxidation of NADH by molecular oxygen. The enzyme was activated by flavine adenine dinucleotide. Whereas some of the hydrogen peroxide formed was removed through the action of an NADH peroxidase, sufficient accumulated in media to inhibit the growth, respiration, and viability of these organisms. The amount of hydrogen peroxide which accumulated varied among strains, and this variation could be related to differences in the properties of the NADH oxidase present. 相似文献
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Julian Balzer Kiara Heuer Erhan Demir Martin A. Hoffmanns Sabrina Baldus Paul C. Fuchs Peter Awakowicz Christoph V. Suschek Christian Opl?nder 《PloS one》2015,10(12)
The proliferation of fibroblasts and myofibroblast differentiation are crucial in wound healing and wound closure. Impaired wound healing is often correlated with chronic bacterial contamination of the wound area. A new promising approach to overcome wound contamination, particularly infection with antibiotic-resistant pathogens, is the topical treatment with non-thermal “cold” atmospheric plasma (CAP). Dielectric barrier discharge (DBD) devices generate CAP containing active and reactive species, which have antibacterial effects but also may affect treated tissue/cells. Moreover, DBD treatment acidifies wound fluids and leads to an accumulation of hydrogen peroxide (H2O2) and nitric oxide products, such as nitrite and nitrate, in the wound. Thus, in this paper, we addressed the question of whether DBD-induced chemical changes may interfere with wound healing-relevant cell parameters such as viability, proliferation and myofibroblast differentiation of primary human fibroblasts. DBD treatment of 250 μl buffered saline (PBS) led to a treatment time-dependent acidification (pH 6.7; 300 s) and coincidently accumulation of nitrite (~300 μM), nitrate (~1 mM) and H2O2 (~200 μM). Fibroblast viability was reduced by single DBD treatments (60–300 s; ~77–66%) or exposure to freshly DBD-treated PBS (60–300 s; ~75–55%), accompanied by prolonged proliferation inhibition of the remaining cells. In addition, the total number of myofibroblasts was reduced, whereas in contrast, the myofibroblast frequency was significantly increased 12 days after DBD treatment or exposure to DBD-treated PBS. Control experiments mimicking DBD treatment indicate that plasma-generated H2O2 was mainly responsible for the decreased proliferation and differentiation, but not for DBD-induced toxicity. In conclusion, apart from antibacterial effects, DBD/CAP may mediate biological processes, for example, wound healing by accumulation of H2O2. Therefore, a clinical DBD treatment must be well-balanced in order to avoid possible unwanted side effects such as a delayed healing process. 相似文献
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The compound X, which had previously been found to be accumulatedin the soybean nodules formed by infection with wild-type H2-uptakenegative Bradyrhizobium japonicum strains, was identified asserinol (2-amino-1,3-propanediol) by means of elementary analysis,infrared spectrometry, 1H-nuclear magnetic resonance, 13C-nuclearmagnetic resonance, high-performance liquid chromatography andgas chromatography/mass spectrometry. During the process ofpurification of compound X, it was also elucidated that 3-amino-1,2-propanediolwas present in the soybean nodules as a minor component. (Received January 6, 1986; Accepted June 16, 1986) 相似文献