Cigarette smoke: protection of alveolar macrophages by glutathione and cysteine

Phagocytosis of bacteria by rabbit alveolar macrophages is inhibited quantitatively by cigarette smoke in vitro. This phagocytoxic effect was abolished by addition of 0.2 to 0.4 micromole of glutathione or cysteine per milliliter of cigarette smoke. Serum protein was required to obtain both the toxic effect of the smoke and the protective action of the sulfhydryl compounds. The protective role of the sulfhydryl agents suggests an oxidant action of the cigarette smoke on these pulmonary cells.     

乌龙型灵芝发酵茶的Ames试验及其品质特征分析

对用乌龙茶制成的乌龙型灵芝发酵茶进行Ames试验,以进一步测定乌龙型灵芝发酵茶的食品安全性,并与乌龙茶生化成分、感官审评进行比较.结果表明,乌龙型灵芝发酵茶对TA97、TA98、TA100和TA1024株试验菌株无诱导致畸变作用.生化成分分析表明:乌龙型灵芝发酵茶的水浸出物、粗蛋白、咖啡碱、多糖、总氨基酸、必需氨基酸和支链氨基酸的含量比乌龙茶高13%、21%、16%、78%、110%、131%和157%;乌龙型灵芝发酵茶的茶多酚含量比乌龙茶低59%.感官评审表明,乌龙型灵芝发酵茶的品质特征明显优于乌龙茶.     

红曲中桔霉素的Ames试验

采用鼠伤寒沙门氏菌试验(Ames试验),通过观察0.2、1.0、5.0、25.0 μg/皿桔霉素处理对鼠伤寒沙门氏菌组氨酸缺陷型菌株TA97、TA98、TA100、TA102回复突变的影响,检测红曲中桔霉素的致突变性.结果表明,桔霉素受试物组回变菌落数均未超过自发回变菌落数的2倍,亦未呈现剂量反应关系,试验结果为阴性,红曲中桔霉素未表现出致突变性.     

Mutagenicity of trimethylphosphate in mice

Subtoxic concentrations of trimethyphosphate, administered orally or parenterally to male mice, produced mutagenic effects, dependent on dosage, in the dominant lethal assay.     

溴氰菊酯的毒性和致突变性的研究进展

由于高效低毒、对光稳定等优点,溴氰菊酯广泛应用于各类害虫、寄生虫防治中。近年来,溴氰菊酯的毒性、致突变性研究逐渐受到人们的关注。笔者综述了溴氰菊酯的毒性、致突变性研究现状。     

硝唑尼特的一般毒性和致突变性研究

通过小鼠经口急性毒性试验、蓄积毒性和耐受性试验研究了硝唑尼特的一般毒性;通过Ames试验、小鼠骨髓细胞微核试验和小鼠精子畸形试验研究了硝唑尼特的致突变性.结果表明:硝唑尼特对小鼠口服LD50为6.295 g/kg,属实际无毒类物质;对小鼠20d给药蓄积系数K＞5.26,属弱蓄积或基本无蓄积毒性,未产生耐受性;对组氨酸缺...     

重组溶葡萄球菌酶的致突变实验

实验用ICR小鼠经口罐胃染毒（骨髓细胞微核实验和精子畸形实验的剂量分别为2500、5000、10000mg·kg^-1）,取其股骨或睾丸组织常规制片,观察分散良好的中期分裂相鼠伤寒沙门氏菌回复突变（Ames）试验采用平板掺入法（剂量分别为0．01、0．04．0．2、1．00、5．00μg·皿^-1）,探讨了重组溶葡萄球菌酶的致突变性;预防其遗传危害性和潜在致癌作用的可能性。结果表明：小鼠骨髓、睾丸细胞染色体畸变实验显示：重组溶葡萄球菌酶给药组与阴性对照组比较,差异无显著性（P〉0．05）,Ames试验显示各菌株的各测试酞度的回变菌落数均未超过自发回变菌落数的2倍。由此证明在本实验条件下,重组溶葡萄球菌酶无致突变性。     

代森锰原药的致突变性试验研究

[目的]探讨代森锰原药的致突变性。[方法]用KM小鼠进行小鼠骨髓多染红细胞微核试验和小鼠睾丸精母细胞染色体畸变试验,以及鼠伤寒沙门氏菌回复突变（Ames）试验。[结果]在小鼠骨髓多染红细胞微核试验和小鼠睾丸精母细胞染色体畸变试验中．阴性对照组与阳性对照组比较,差异有显著性（P〈0．01）;各剂量组与阴性对照组比较,差异均无显著性（P〉0．05）,且均低于阳性对照组（P〈0．05,P〈0．01）。在Ames试验中,4株试验菌在0．1～1．0mg／皿的试验剂量下（活化或非活化）均没有引起自发回变数2倍增加。[结论]根据《农药登记毒理学试验方法》中的评定标准,小鼠骨髓多染红细胞微核试验、小鼠睾丸精母细胞染色体畸变试验和鼠伤寒沙门氏菌回复突变试验（Ames试验）在所选剂量范围内结果均为阴性,代森锰原药未呈现致突变性。     

应用Ames试验对氟化物诱发突变和抗突变活性的研究

应用Ames鼠伤寒沙门氏菌/微粒体酶技术研究了氟化钠(NaF)对TA98和TA100两个组氨酸缺陷型菌株的致突变和抗突变活性。结果表明,NaF对所试微生物缺乏致突变活性,且在中毒浓度下(>2000μg·皿-1)降低了试验菌株的回复突变频率;NaF对已知的阳性致突变物也未显示抗突变效应。     

中药川贝对小鼠急性毒性和致突变性的研究

[目的]通过急性毒性试验和微核试验了解川贝水提取物对小鼠的急性毒性和致突变性.[方法]川贝急性毒性试验中采用最大给药量,记录小鼠给药1周内的生理反应及体征变化,然后通过剖检及血液学指标研究川贝的急性毒性.通过微核试验检测川贝水提取物对小鼠骨髓嗜多染红细胞的影响,了解川贝的致突变性.[结果]小鼠在最大给药量折合生药为90 000 mg/kg的剂量下没有明显异常反应,体重、血液指标与对照组无差异,剖检无内脏病变.微核试验结果呈阴性.[结论]川贝水提取物对小鼠无急性毒性及致突变性,可作为兽医临床用药安全使用.     

沙拉沙星的致突变性和致畸性研究

 选用Ｗｉｓｔａｒ大鼠和昆明系小鼠对沙拉沙星的遗传毒性进行研究。试验结果显示，沙拉沙星在抑菌剂量之下对鼠伤寒沙门氏菌不产生致突变作用；沙拉沙星不引起小鼠骨髓有微核多染红细胞率增加；显性致死试验中，沙拉沙星试验结果为阴性；５和 ５０ｍｇ／ｋｇ ｂ．ｗ．剂量沙拉沙星对母鼠的生殖机能和胎鼠的生长发育无明显影响，对胎鼠不产生致畸作用，而 ５００ｍｇ／ｋｇ ｂ．ｗ．剂量沙拉沙星对胎鼠体长和骨骼发育有一定影响，但不存在剂量反应关系。上述结果表明，沙拉沙星无明显的致突变性和致畸性。     

Studies on Mutagenicity and Teratogenicity of Sarafloxacin

Wistar rats and closed Kunming strain mice were selected to study the genetic toxicity of sarafloxacin. The results indicated that sarafloxacin had no significant toxic effect of an excreted mutagen in S. typhimurium strains, and did not induce significantly higher percentages of polyehromatic erythrocytes with micronuclei (MNPCE) in mice. No significant mutagenic activity was observed in dominant lethal assay.At 5 and 50mg/kg b.w. , sarafloxacin did not produce significant effects on the reproductive parameters of litters and fetal growth, and did not induce the teratogenic effects on fetuses. Sarafloxacin induced some toxic effects on body length and skeletal growth in fetuses of 500mg/kg b.w., but had no significant dose - response relationship among the administered dosages of sarafloxacin. The results of the genetic toxicology above indicated that no evidence showing sarafloxacin was mutagenic and potentially teratogenic for animals.     

抗性和敏感小菜蛾谷胱甘肽-S-转移酶和谷胱甘肽的比较

研究了抗性和敏感小菜蛾谷胱甘肽 - S-转移酶 ( GSTs)在不同发育期的变化及有机磷类杀虫剂对虫体谷胱甘肽 ( GSH)质量摩尔浓度的影响 .结果表明 :抗性和敏感小菜蛾 GSTs比活力在各发育期中变化不大 ,但虫体 GSTs总活力随虫体生长发育而显著增加 ,在 4龄和蛹期达到最大值 .抗性小菜蛾 GSTs活力明显高于敏感小菜蛾 .甲胺磷和水胺硫磷对敏感小菜蛾幼虫 GSH影响不明显 ,但可导致抗性小菜蛾 GSH质量摩尔浓度的显著降低 .因此可以认为 ,GSTs活力增高和 GSH的结合作用应是小菜蛾对有机磷类杀虫剂抗性的重要机制 .     

中药罗汉果对小鼠急性毒性和致突变性研究

[目的]研究罗汉果水提取物在小鼠体内的急性毒性及致畸变性效应,为罗汉果临床用药安全提供理论依据。[方法]对小鼠进行罗汉果水提取物最大给药量急性毒性试验,观察小鼠给药后的体征及生理变化,进行血液检查以及剖检;采用小鼠骨髓嗜多染红细胞微核试验进行致畸变性检测。[结果]在最大给药量90 000 mg/kg剂量下,小鼠无明显中毒症状,生理指标、血液与空白对照组无显著差异,内脏器官解剖无病理变化;微核试验结果呈阴性。[结论]罗汉果水提取物无急性毒性以及致突变性。     

吡啶酸铬的致突变性和生殖毒性研究

 选用Wistar大鼠和昆明系小鼠对吡啶酸铬的遗传毒性进行研究。结果表明 ,吡啶酸铬在抑菌剂量下对鼠伤寒沙门氏菌TA97、TA98、TA10 0和TA10 2不产生致突变作用 ;吡啶酸铬经口染毒剂量为 5～ 0 .5g·kg-1BW时不引起小鼠骨髓有微核多染红细胞率增加 ;吡啶酸铬对小鼠的显性致死试验结果为阴性 ;饲料中添加 2和 2 0mg·kg-1剂量吡啶酸铬对母鼠的生殖机能和胎鼠的生长发育无明显影响 ,对胎鼠不产生致畸作用 ,而 2 0 0mg·kg-1剂量吡啶酸铬对胎鼠骨骼发育有一定影响 ,但不存在剂量 反应关系。由此得出 ,吡啶酸铬无明显的致突变性和致畸性。     

RNA-dependent cysteine biosynthesis in archaea

Several methanogenic archaea lack cysteinyl-transfer RNA (tRNA) synthetase (CysRS), the essential enzyme that provides Cys-tRNA(Cys) for translation in most organisms. Partial purification of the corresponding activity from Methanocaldococcus jannaschii indicated that tRNA(Cys) becomes acylated with O-phosphoserine (Sep) but not with cysteine. Further analyses identified a class II-type O-phosphoseryl-tRNA synthetase (SepRS) and Sep-tRNA:Cys-tRNA synthase (SepCysS). SepRS specifically forms Sep-tRNA(Cys), which is then converted to Cys-tRNA(Cys) by SepCysS. Comparative genomic analyses suggest that this pathway, encoded in all organisms lacking CysRS, can also act as the sole route for cysteine biosynthesis. This was proven for Methanococcus maripaludis, where deletion of the SepRS-encoding gene resulted in cysteine auxotrophy. As the conversions of Sep-tRNA to Cys-tRNA or to selenocysteinyl-tRNA are chemically analogous, the catalytic activity of SepCysS provides a means by which both cysteine and selenocysteine may have originally been added to the genetic code.     

Studies on the Mutagenicity and Teratogenicity of Kuianchun and Its Potential Carcinogenicity Prediction

Kuianchun is a newly synthesized antibacterial and growth-promoting drug. This paper selected a battery of three short-term tests, including Ames test, micronucleus test and sperm abnormality test, to detect the mutagenicity of Kuianchun. The carcinogenicity prediction and battery selection method (CPBS method) was used to determine the probability of carcinogenicity of Kuianchun based upon the results of shortterm tests mentioned above. In addition, traditional teratogenic test was selected to study teratogenicity of Kuianchun. In Ames test, Kuianchun showed mutagenic for Salmonella typhimurium strains TA98 and TA100 in the absence and presence of microsomal metabolic activation system (S9-mix). However, the mutagenicity was reduced by the addition of S9-mix. In micronucleus test, Kuianchun was administered intra-peritoneally to male mouse 30 hours and 6 hours before they were killed respectively. The result indicated that there was no significant difference on the number of micronucleated polychromatic erythrocytes (PCEs) in the mouse bone marrow induced by Kuianchun compared with the negative contrast (50% DMSO) (P ＞ 0.05). In sperm abnormality test, Kuianchun was administered through a gastric incubation to male mouse as a suspension in 2% Tween-80. The dosage levels were 450, 750, 1000 and 1500mg/kg per day for 5 days. The result indicated that the percentage of abnormal sperms induced by Kuianchun was not significant compared with the negative contrast (P＞0.05). In traditional teratogenic test, Kuianchun was given orally to pregnant mouse at 1/30,1/20 and 1/15 LDs0 during 6 - 15days of pregnancy period (the LD50 = 9000mg/kg). No toxicity was found either on mother and embryo in mouse, and teratogenic effects were also not observed at all tested dosages. The probability of carcinogenicity of Kuianchun is 23.8 % (θ = 0.238). The result demonstrated that Kuianchun is a non-carcinogen.