一株甲胺磷分解菌的分离及其特性研究

通过富集驯化和选择性培养,从福建三农集团污水处理池的活性污泥中筛选到一株能以甲胺磷为惟一碳源和氮源的细菌DM-1。研究了该菌形态与部分生理生化特性。DM-1菌在无机盐基础培养基中对甲胺磷的最高耐受浓度为1500mg／L,DM-1菌最适生长条件：起始pH值8．0,培养温度28℃,接种量3．0％,摇床转速150r／min,培养时间72h。最佳碳、氮源分别为D-甘露醇和蛋白胨。     

不同地理种群小菜蛾对甲胺磷的抗药性

采用浸叶法研究了福州建新镇、福建农林大学校园内、闽侯县上街镇和闽侯县甘蔗镇等地田间小菜蛾种群对甲胺磷的抗性水平及抗性机制。结果表明,与敏感小菜蛾相比,上述4个田间小菜蛾种群已对甲胺磷产生了34-82倍的抗性水平。敏感小菜蛾乙酰胆碱酯酶(AChE)的Ki值是田间抗性小菜蛾AChE的Ki值的17.3-39.1倍。不同小菜蛾种群对甲胺磷的抗性水平也存在着差异,小菜蛾种群AChE对甲胺磷的敏感性大小与其对甲胺磷的抗性水平高低显著相关。     

假单胞菌S-2降解甲胺磷性能的研究

从甲胺磷生产车间分离到一株假单胞菌编号为S-2。S-2可利用甲胺磷为唯一氮源,但不能利用甲胺磷为唯一磷源。该文对S-2体内具有的降解甲胺磷的酶类进行了研究,初步断定：S-2可代谢产生酸性磷酸酶,主要在胞外降解甲胺磷。S-2在甲胺磷诱导的情况下,这些降解酶类可大量聚积。用诱导过的菌液降解甲胺磷比未经诱导的快了2d左右。     

利用PLFA、CLPPs和ARDRA标记分析甲胺磷对土壤微生物群落的影响

利用磷脂脂肪酸(PLFA)、群落水平生理活性(CLPPs)和扩增核糖体DNA限制性分析(ARDRA)标记,综合评估低浓度和高浓度甲胺磷连续施用2和4 yr后对土壤微生物群落结构、功能和遗传多样性的影响。结果表明,甲胺磷胁迫使土壤微生物生物量减少而细菌(革兰氏阴性菌)数量增加,同时使微生物群落功能多样性下降而遗传多样性提高;处理2 yr后高浓度甲胺磷胁迫对微生物群落的影响较低浓度胁迫更为明显,处理4 yr后两个浓度胁迫则具有相似的显著影响,表明不同浓度甲胺磷的长期胁迫均能对微生物群落造成严重破坏。     

松墨天牛幼虫体内神经毒性酯酶和乙酰胆碱酯酶对甲胺磷敏感性的比较

松墨天牛Monochamus alternatus Hope是传播松材线虫Bursaphelenchus xylophilus Nickle的主要媒介昆虫,在其化学防治中经常使用有机磷杀虫剂,而这类杀虫剂有些可通过作用于神经毒性酯酶（neurotoxic esterase, NTE）使敏感的脊椎动物产生迟发性神经毒性。为了深入理解有机磷杀虫剂对害虫毒杀作用机理,增强对昆虫体内NTE活性的了解,我们在松墨天牛中开展了相关的研究。通过差异测定法和经典的乙酰胆碱酯酶（acetylcholinesterase, AChE）活性测定方法,分别测定了松墨天牛幼虫体内NTE和AChE的活性。结果发现,在松墨天牛体内存在NTE活性,其头部的NTE活力为2.80±0.30 nmol·min^-1·mg^-1,比脂肪体高出了近10倍,但仍较鸟类等脊椎动物为低。体内实验显示,松墨天牛体内NTE可被甲胺磷所抑制; 但在体外实验条件下,甲胺磷对来自松墨天牛头部的NTE活性并没有产生明显抑制作用,而此浓度下的甲胺磷对AChE表现出较高水平的抑制作用。表明松墨天牛体内NTE和AChE对甲胺磷的敏感性完全不同。     

褐飞虱抗甲胺磷品系的交互抗性和抗性生化机制

用甲胺磷筛选的褐飞虱Nilaparvata lugens品系（R）,对甲胺磷的抗性达到43.74倍,对马拉硫磷、二嗪磷、异丙威、仲丁威及醚菊酯都表现出一定的交互抗性,而对氰戊菊酯和吡虫啉的交互抗性不显著。为了研究褐飞虱对甲胺磷抗性和对其它药剂交互抗性产生的机制,进行了活体增效试验和离体生化实验。用2 μg/头的增效剂预处理试虫的活体增效实验结果显示,在甲胺磷筛选品系（R）中, TPP(triphenyl phosphate, 磷酸三苯酯)对甲胺磷的增效倍数达到4.54,TPP对马拉硫磷、二嗪磷、仲丁威、异丙威都表现出一定的增效作用,增效比分别为2.76、2.07、2.17和1.64;PBO(piperonyl butoxide,胡椒基丁醚)对甲胺磷、马拉硫磷和醚菊酯有一定的增效作用;DEM(diethyl meteate, 顺丁烯二酸二乙酯)的增效作用不明显。研究离体情况下增效剂对三种解毒酶活性的影响发现,TPP对R品系酯酶活力抑制作用很强（抑制率69.04%）,PBO对多功能氧化酶（MFO）具有一定的抑制作用（抑制率29.30%）,而TPP和PBO在F品系和S品系中对酯酶和MFO的抑制作用都较小;DEM在三个品系中对谷胱甘肽-S-转移酶的抑制作用都很小。由此可见,酯酶在褐飞虱对甲胺磷的抗性中起最主要作用,在马拉硫磷、二嗪磷、异丙威和仲丁威的交互抗性中起很重要作用;MFO可能在甲胺磷抗性和醚菊酯、马拉硫磷的交互抗性中起一定作用。     

Effects of methamidophos and glyphosate on copper sorption-desorption behavior in soils

A batch-equilibration technique was employed to study the impact of two organo-phosphorus pesticides methamidophos (MDP) and glyphosate (GPS) on copper (Cu2+) sorption-desorption for phaeozem and burozem collected from Northeastern China. The addition of the two pesticides decreased Cu2+ sorption, increased Cu2+ desorption and prolonged the equilibrium time of Cu2+ sorption-desorption. But GPS appeared to exert a stronger influence on Cu2+ sorption-desorption due to its stronger complexion with Cu2+. When MDP was added, Cu2+ sorption-desorption was linearly correlated with MDP treatment concentrations. But in the presence of GPS, Cu2+ sorption first underwent a rapid decrease period, and then slowly tended towards a steady period. The reverse pattern could be found for Cu2+ desorption in the presence of GPS. Without pesticides and with the existence of MDP, Cu2+ sorption-desorption kinetics was well conformed to two-constant equation and Elovich equation. But that was not the case for Cu2+ desorption kin     

Positive correlation of methamidophos resistance between Lipaphis erysimi and Diaeretilla rapae and effects of methamidophos ingested by host insect on the parasitoid

Temporal and spatial correlated variations on the methamidophos resistance and biomolecular rate constant of acetylcholinesterase to insecticides were found between the turnip aphid, Lipaphis erysimi and its endoparasitoid, Diaeretilla rapae , collected from field colonies and an insecticide-free field insectarium in Fujian, China. Compared to the related susceptible insectarium population, L. erysimi and D. rapae displayed 7.4–29.2- and 2.6–9.2-fold resistance ratios, respectively. In addition, two populations of L. erysimi with different methamidophos resistance levels, that is, a field (with 5.8-fold resistance ratio) and an insectarium population, were used to study the effects of methamidophos ingested by the host insect on D. rapae development. The percentage of D. rapae cocoon formation decreased significantly when the parasitized L. erysimi were fed on cauliflower leaves treated with methamidophos at lethal concentration dosages 10 (LC₁₀) or LC₅₀. At LC₅₀ dosages the percentage of D. rapae cocoon formation and adult emergence decreased significantly. When the parasitized L. erysimi were fed on methamidophos at LC₉₀ dosage, no D. rapae cocoons were found. When the field or insectarium L. erysimi were treated with methamidophos at LC₁₀, the susceptibility to methamidophos in the adult D. rapae emerged from the treated host insect was similar to the control. However, the susceptibility to methamidophos in the adult D. rapae became lower than the control when the host insects were treated at LC₅₀ dosages. The data thus suggested that the methamidophos ingested by the host insect L. erysimi could be an important factor in the endoparasitoids' insecticide resistance development. The natural selectivity would favor the parasitoids that had developed an insensitivity to the insecticide(s).     

甲胺磷降解菌的筛选及降解特性研究

从长期受有机磷农药污染的土壤中分离到1株能降解甲胺磷的菌株B15,经生理生化鉴定为巨大芽孢杆菌(Bacillus megaterium)。在甲胺磷无机盐培养基(甲胺磷浓度为0.5%)生长时,最适生长温度为28℃,最适pH为7.0,摇床培养(28℃190 r/min)48 h降解率达到83%。菌株在甲胺磷浓度为1%的无机盐培养基上能生长,但是在甲胺磷浓度为0.5%的无机盐培养基上生长最好,降解率最高。外加碳氮源对菌株的降解率有所提高,但是超过某一浓度降解率随着浓度的增加反而下降。     

Heterogeneity of Rice Glutelin

Three forms of endopolygalacturonase from Saccharomyces fragilis (Kluyveromyces fragilis) were separated by a procedure including adsorption on Amberlite IRC-50, CM Sephadex C-50 column chromatography and repeated preparative disc electrophoresis. Each endo-PG was almost homogenoeus as judged by polyacrylamide gel electrofocusing and disc electrophoresis. The three enzyme were designated as enzymes I, II and III. Enzymes I and II were similar but enzyme HI different from I and II in isoelectric point. The three enzymes resembled one another in eznyme action on pectic acid and other properties. All the three enzymes showed macerating activity toward the potato and carrot tissues.