氯氰菊酯降解菌CY22-7的分离鉴定及降解特性研究

从采集的多种土壤样品中.获得了19株在3种筛选平板上均生长良好的候选氯氰菊酯降解菌.通过生理生化特性鉴定和16S rDNA序列的测定及比对.将其中的氯氰菊酯降解菌CY22-7鉴定为中华根瘤菌属(Sinorhizobium sp.).同时,对氯氰菊酯降解菌CY22-7的降解特性研究结果表明:(1)氯氰菊酯降解菌CY22-7以5%(体积分数)的接种鼍接种到氯氰菊酯起始质量浓度为100 mg/L的氯氰菊酯乙醇培养基后,于200 r/min、30℃摇床中培养.经过6 d的培养,氯氰菊酯降解菌CY22-7降解了约60%的氯氰菊酯.(2)加人外源营养物质有利于促进氯氰菊酯的降解.其中,葡萄糖和酵母提取物的促进作用最为明显.(3)氯氰菊酯降解菌CY22-7降解氯氰菊酯的最适温度为30℃,最佳pH为6.0.     

Effect of copper on the degradation of pesticides cypermethrin and cyhalothrin

The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers.     

4种新型杀虫剂对黄色羽摇蚊(Chironomus flaviplumus)老熟幼虫的急性毒性

测定了峰升(15%杀单·唑磷乳油)、稻卫(20.2%阿维·唑磷乳油)、蚜螨克星(1.8%阿维·吡乳油)和蔬卫(2.4%高氯·阿维乳油)4种新型杀虫剂对黄色羽摇蚊(Chironomus flaviplumus)老熟幼虫的急性毒性.结果表明:峰升处理黄色羽摇蚊幼虫后24 h,不同浓度间的存活率无显著差异,而在其他时间段(48、72、96 h),随着杀虫剂浓度的增加,存活率逐渐下降.其他3种杀虫剂处理黄色羽摇蚊幼虫4 d,随着杀虫剂浓度的增加,每天的存活率也呈下降趋势.峰升、稻卫、蚜螨克星和蔬卫对黄色羽摇蚊幼虫48 h的LCs0分别为0.1735、0.0249、0.0015和0.0046 mg·L-1.蚜螨克星毒性最高,毒性在同一数量级的还有蔬卫,其次为稻卫.峰升毒性最低,但仍属高毒杀虫剂.     

红球菌CDT3降解氯氰菊酯的特性及途径

以一株降解氯氰菊酯的红球菌(Rhodococcussp.)CDT3为材料,研究了CDT3降解氯氰菊酯的最适条件(温度、pH值、接种量、培养时间、添加营养物).结果表明,在温度30℃,pH8.0时,CDT3对氯氰菊酯的降解率最高,添加少量葡萄糖、蛋白胨、酵母汁均能促进它对氯氰菊酯的降解.研究了CDT3降解氯氰菊酯的代谢途径,通过GC-MS分析,证实氯氰菊酯被CDT3降解后的产物是3-苯氧基苯甲酸(3-PBA)和二氯菊酸(DCVA),推测氯氰菊酯是由CDT3产生的羧酸酯酶降解的,作为验证,提取了CDT3的粗酶液,并且通过聚丙烯酰胺凝胶电泳(PAGE)检测了羧酸酯酶.     

Assessing cypermethrin-contaminated soil with three di erent earthworm test methods

A series of tests (lethal, sublethal, and behavioral) on earthworms were conducted as an eco-assessment of pesticides. In this study, the toxicity of cypermethrin-contaminating soil on adult and juvenile earthworms was assessed. Beside the acute and chronic tests, an avoidance response test was carried out. It was shown that the all-round toxicity from cypermethrin was weak on adult earthworms. Compared with adult earthworms, the toxicity of juvenile earthworms from cypermethrin especially chronic toxicity increased significantly. Growth and reproduction of earthworms appeared to be more severely a ected by cypermethrin at juvenile stage than at adult stage. Applied at 10 mg/kg, cypermethrin had obvious adverse impact on the growth of juvenile earthworms, while 20 mg/kg, cypermethrin caused significant toxic e ects in reproduction. The results also indicated that ecotoxicological risk assessment using only adult specimens may underestimate the e ects of cypermethrin on soil invertebrate populations.     

水中BPMC等残留农药的分析方法研究

BPMC、Propyzamide、TPN、Diazinon、IBP、MEP、Benthiocarb、Isoxathion、EPN等农药是目前广泛使用的除草剂和杀虫剂,其中部分农药如BPMC被列为毒害品,然而目前还没有可行有效的、针对以上物质的统一检测方法。选用了合适的有机溶剂对多种组分进行同时萃取,经过净化后采用气相色谱-质谱法测定,分析效果较好。     

高效氯氰菊酯急性暴露中斑马鱼相关酶活性和基因表达变化

高效氯氰菊酯广泛地应用于农业生产及日常生活中的害虫防治,但对水生生物却毒性极高。为探究高效氯氰菊酯对斑马鱼的急性毒性,以总超氧化物歧化酶(总SOD)、过氧化氢酶(CAT)和乙酰胆碱酯酶(ACh E)活性以及相关的基因表达量变化为检测指标,研究其对斑马鱼成鱼的影响。急性毒性试验结果显示,高效氯氰菊酯对斑马鱼属剧毒物质,斑马鱼的急性中毒症状为身体蜷曲、抽搐,鳃盖扇动加快,游动能力减弱,间歇性出现无规律急速游动和撞壁行为。酶活测定结果显示,斑马鱼组织中总SOD、CAT和ACh E活性与高效氯氰菊酯呈现低浓度诱导、高浓度抑制的剂量效应关系;相关基因表达量的检测结果显示,高效氯氰菊酯会诱导斑马鱼肝脏、肠和脑中Sod1、Cat以及Ache的m RNA表达上调。研究表明,高效氯氰菊酯的神经毒性和氧化损伤共同造成了斑马鱼的中毒甚至死亡。     

Chemical and photochemical transformation of fenamiphos—an organophosphorus nematicide

Fenamiphos, an organophosphorus nematicide and its hydrolysis product 4‐methylthio‐m‐cresol under dye‐sensitized photo‐oxidative conditions yielded the corresponding sulfoxide analogs. Under UV‐photolytic conditions, fenamiphos in methanol solution gave mainly the cleavage products. To obtain standards of the oxidative degradation products/metabolites in larger quantities, fenamiphos and fenamiphos phenol was chemically transformed to the corresponding sulfoxide and sulfone. Their structures were confirmed by ‘HNMR and mass spectra.     

Acute effects of low-dose cypermethrin on male rat cells

Effects of synthetic pyrethroid insecticide α-cypermethrin were investigated following intradermal dose (5–50 mM) of cypermethrin to male albino Wistar rats. Glucose, protein, cholesterol, triglycerides, urea, uric acid, creatinine, hemoglobin, blood RBC, and WBC content were determined 6 h after pesticide administration. Biochemical parameters and blood cell count changed significantly in treated rats at all doses. Low-dose cypermethrin affected early biochemical changes in rats.