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1.
The mycotoxin cyclopiazonic acid (CPA) is a potential contaminant of processed foods, grain and poultry. Twelve male Sprague-Dawley rats were given oral doses of 0, 0.2, 0.6, 2.0 or 4.0 mg CPA/kg body weight/day for 13 consecutive weeks to study its potential subchronic toxicity. No dose-related mortality or morbidity occurred. General appearance, behavior, body weight gain and food consumption of all groups were similar. CPA had no definite adverse hematologic or serum chemistry effects, although serum creatinine concentrations of rats given 2.0 and 4.0 mg CPA/kg BW were increased after seven and 13 weeks. Mild to focally moderate acute inflammation of the lamina propria and submucosa of the gastric epithelium was found in animals given 0.6 mg CPA/kg BW. No other dose-related microscopic lesions were found. Ultrastructural examination of the livers revealed subtle disruption of the cisternal pattern of the endoplasmic reticulum with ribosomal detachment in animals receiving 4.0, but not 2.0, mg CPA/kg BW. These data suggest that the toxic effects in rats of repeated, daily oral exposure to CPA may be less than previously reported. The possible relationship between toxicity and CPA epimerization is considered. 相似文献
2.
Corinne Vander Wauven Alfred Jann Dieter Haas Thomas Leisinger Victor Stalon 《Archives of microbiology》1988,150(4):400-404
Most Pseudomonas aeruginosa PAO mutants which were unable to utilize l-arginine as the sole carbon and nitrogen source (aru mutants) under aerobic conditions were also affected in l-ornithine utilization. These aru mutants were impaired in one or several enzymes involved in the conversion of N2-succinylornithine to glutamate and succinate, indicating that the latter steps of the arginine succinyltransferase pathway can be used for ornithine catabolism. Addition of aminooxyacetate, an inhibitor of the N2-succinylornithine 5-aminotransferase, to resting cells of P. aeruginosa in ornithine medium led to the accumulation of N2-succinylornithine. In crude extracts of P. aeruginosa an ornithine succinyltransferase (l-ornithine:succinyl-CoA N2-succinyltransferase) activity could be detected. An aru mutant having reduced arginine succinyltransferase activity also had correspondingly low levels of ornithine succinyltransferase. Thus, in P. aeruginosa, these two activities might be due to the same enzyme, which initiates aerobic arginine and ornithine catabolism.Abbreviations OAT
ornithine 5-aminotransferase
- SOAT
N2-succinylornithine 5-aminotransferase
- Oru
ornithine utilization
- Aru
arginine utilization 相似文献
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1. A sensitive fluorimetric procedure for the assay of d-amino acid oxidase has been developed. 2. The method depends on the formation of a fluorescent derivative, 2-hydroxy-3-methylquinoxaline, on condensation of pyruvate with o-phenylenediamine in acid medium. 3. 2-Hydroxy-3-methylquinoxaline fluoresces strongly in 50% (v/v) sulphuric acid after excitation at 375mmu. A single emission peak is observed at 480mmu. 4. Formation of the quinoxaline is dependent on time, temperature, acidity and relative concentration of reactants. 5. A particulate preparation from mouse kidney required FAD for optimum activity at pH8.5; K(m) was 3.8x10(-3)m; K(FAD) was 1.4x10(-7)m and the reaction was strongly inhibited by p-chloromercuribenzoate and phenylmercuric acetate. 6. Subcellular fractionation on a sucrose density gradient confirmed that the d-amino acid oxidase was localized on small granules. 相似文献
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Glenn C. Hodding Michael Jann Irving P. Ackerman 《The Western journal of medicine》1980,133(5):383-391
Drug withdrawal syndromes reportedly have been caused by numerous pharmacological agents, but only a few drugs have been adequately studied in this regard. Criteria for evaluating drug withdrawal syndromes have been proposed. Sedative-hypnotic agents, opiates, corticosteroids, clonidine, tricyclic antidepressant medications and beta-adrenergic blocking agents meet the criteria for such syndromes. Gradual tapering of the dose of these drugs is recommended when therapy must be discontinued. Whether or not other drugs cause rebound reactions is questionable, but caution should be used when discontinuing drugs for which numerous reports of withdrawal syndromes exist. 相似文献
8.
Studies on synaptosome mitochondrial respiration are complicated by “free” mitochondria. Veratridine stimulation of synaptosomal respiration was due to increased Na+ cycling at the synaptosome membrane associated with increased oxidative phosphorylation of intraterminal ADP and was inhibited by oligomycin, ouabain or Na+ free medium. Atractylate or carboxyatractyloside failed to block veratridine-stimulated respiration but inhibited exogenous-ADP-stimulated respiration. Protein synthesis in the synaptosome fraction was inhibited by oligomycin, valinomycin or 2,4-dinitrophenol but was unaffected by excess atractylate. No change in synaptosomal adenine nucleotide content was found in the presence of atractylate, although a significant decrease in the [ATP]/[ADP] was found with oligomycin, veratridine or valinomycin. These findings show that atractylate does not modify intraterminal mitochondrial energy transduction and indirectly suggest an impermeability of the synaptosome membrane to atractylate. 相似文献
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The biocontrol properties of Trichoderma species are well documented, but their effectiveness in antagonism of the problematic Sclerotium cepivorum, the causal agent of white rot in Allium species, appears limited with reports of significant control only relating to deliberately-mutated strains of Trichoderma. Our previous studies have indicated the possibility of using selected naturally-occurring strains of the antagonist in the suppression of other diseases; now in vitro and controlled environment in vivo studies have indicated that a degree of control of Onion White Rot is possible, and that the selected antagonist strains can be used in integrated treatments with Iprodione to good effect. The possible value of such treatments is considered in light of other approaches to the suppression of this continuing problem. 相似文献