Inhibition of atrazine degradation by cyanazine and exogenous nitrogen in bacterial isolate M91-3
Inhibition of atrazine degradation by cyanazine and exogenous nitrogen in bacterial isolate M91-3
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DOI：
10.1007/s002530051405
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发表时间：
1999-03-01
影响因子：
5
通讯作者：
Radosevich, M
中科院分区：
文献类型：
--
作者：
Gebendinger, N;Radosevich, M
各种S-三嗪除草剂和氮肥经常作为共污染物出现在农药制造和分配设施中。研究了细菌分离物M91-3在洗涤细胞悬浮液和粗细胞提取物中对莠去津和氰草津的降解。氰草津竞争性抑制阿特拉津降解。阿特拉津的最大降解速率（Vmax）是41倍高，抑制剂（Ki）的半饱和常数是1.3倍，在粗细胞提取物中比洗涤细胞悬浮液，表明细胞吸收影响降解的s-三嗪。先前暴露于阿特拉津和西玛津的培养物表现出相当的阿特拉津降解率，而暴露于氰草津、丙嗪、莠灭净、氰尿酸、2-羟基阿特拉津、缩二脲和尿素的细胞表现出缺乏阿特拉津降解活性。生长在外源性无机氮的存在下抑制随后的阿特拉津降解活性洗涤细胞悬浮液中，这表明调节S-三嗪和氮代谢在此细菌分离株。这些研究结果具有显着的影响，S-三嗪类除草剂在农业环境中的环境命运，因为这些除草剂经常被施加到土壤中接受氮肥。此外，这些结果表明，生物修复的S-三嗪污染的网站（常见的在玉米带的农药配送设施）可能会受到抑制的存在下，出现的共同污染物的N肥料。
A variety of s-triazine herbicides and nitrogen fertilizers frequently occur as co-contaminants at pesticide manufacturing and distribution facilities. The degradation of atrazine and cyanazine by the bacterial isolate M91-3 was investigated in washed-cell suspensions and crude cellular extracts. Cyanazine competitively inhibited atrazine degradation. The maximum atrazine degradation rate (V-max) was 41 times higher and the half-saturation constant for the inhibitor (K-i) was 1.3 times higher in the crude cellular extract than in the washed-cell suspension, suggesting that cellular uptake influenced degradation of the s-triazines. Cultures that had received prior exposure to atrazine and simazine exhibited comparable atrazine degradation rates, while cells exposed to cyanazine, propazine, ametryne, cyanuric acid, 2-hydroxyatrazine, biuret, and urea exhibited a lack of atrazine-degradative activity. Growth in the presence of exogenous inorganic nitrogen inhibited subsequent atrazine-degradative activity in washed-cell suspensions, suggesting that regulation of s-triazine and nitrogen metabolism are linked in this bacterial isolate. These findings have significant implications for the environmental fate of s-triazines in agricultural settings since these herbicides are frequently applied to soils receiving N fertilizers. Furthermore, these results suggest that bioremediation of s-triazine-contaminated sites (common at pesticide distribution facilities in the cornbelt) may be inhibited by the presence of N fertilizers that occur as co-contaminants.