单甲脒农药的微生物降解代谢研究

研究了门多萨假单胞菌ＤＲ－８菌株对单甲脒农药的降解代谢。该菌利用率甲脒作为生长的唯一氮源，其对单甲脒的呼吸作用试验确证了该农药的生物可降解性。单甲脒对细菌生物氧化代谢关联酶活性的影响研究表明，脱氢酶对单甲脒较敏感，而ＮＡＤＨ氧化酶则耐受性较强。

MICROBIAL DEGRADATION METABOLISM OF N-2,4-DIMETHYL -PHENYL-N'-METHYLFORMAMIDINE(DMA)

Degradation metabolism of N-2, 4 dimethyl phenyl-N'-methylformamidine (DMA) by Pseudomonas mendocina DR-8 was studied. The strain DR-8 and its mixed culture with other bacteria were able to utilize DMA as sole nitrogen source for growth and degrading the pesticide. The result from respiration assay by intact cells of strain DR-8 for DMA also demonstrated that the pesticide was biodegradable.Effects of DMA on the activity of enzymes indicated that dehydrogenase was susceptible to DMA, but NADH oxidase was rather tolerant to DMA. Properties of the DMA degrading enzyme were studied, the enzyme was an intracellular one, mainly located in the cell wall and membrane, the Km of the enzyme for degrading DMA was 5.14 mmol/L. The results from the detection of the intermediate metabolites for degradation of DMA by ultraviolet spectrum and thin layer chromatography as well as ammonia assay showed that biodegradation products of DMA were 2, 4 dimethylaniline and ammonia. Above study showed that the degradation of DMA by Pseudomonas mendocina DR-8 was a cometabolism.