苄嘧磺
发布时间：2018-11-27 08:13
【摘要】：乙草胺、苄嘧磺隆以及乙·苄复配制剂是目前最广泛使用的稻田新型除草剂。但大量施用对后茬敏感作物造成明显药害,对农田生态环境带来严重污染。除草剂在土壤中的残留一般通过物理、化学与生物学过程而消失,其中微生物降解是主要途径。因此,利用降解微生物消除环境污染具有重要意义。通过富集培养筛选出一个能以乙草胺为唯一碳源、并耐受苄嘧磺隆的复合菌系66C,从66C复合菌系中分离得到4个细菌菌株,分别命名为66C-1、66C-2、66C-3、66C-4。通过形态特征、分子系统发育分析和生理生化3方面对菌株进行鉴定,将66C-1、66C-2、66C-3、66C-4分别鉴定为粘质沙雷氏菌、Psedomona shunanensi s、恶臭假单胞菌、硝化还原假单胞菌。单一的菌株不能降解乙草胺,只有当这4株菌以1:1:1:1混合培养时才会生长,达到共同降解乙草胺的目的,将4株菌等比例构成的混合菌重新命名为HXDW。在乙草胺初始浓度为100mg/L、pH9.0、NaCl浓度为2%的无机盐培养基中25℃培养时,混合菌HXDW生长最好。10mg/L P b2+明显促进复合菌的生长,而10mg/L的Cd2+和Mn2+抑制复合菌的生长。降解菌系只能利用乙草胺作为唯一碳源,而不能利用丁草胺、异丙甲草胺和吡氟酰草胺。利用LC-MS测定混合菌HXDW培养液中乙草胺的残留量,发现乙草胺的7d降解率为14%。利用UHPLC-QTOF-MS测定混合菌HXDW对乙草胺的代谢产物,初步断定乙草胺经羟基化、氧化、脱氯等过程形成中间产物3-羟基-2-氨基苯甲酸。SDS-PAGE电泳分析显示,经100mg/L乙草胺或100m g/L乙草胺与30mg/L苄嘧磺隆的复配剂诱导后,混合菌HXDW的全蛋白图谱出现3条约58.0、50.0和43.0kDa大小的特异性蛋白条带;而30mg/L苄嘧磺隆诱导的HXDW培养液全蛋白图谱呈现出80.0、64.0、58.0、50.0、43.0、38和25kDa等7条特异性的蛋白条带。通过渗透休克法提取混合菌HXDW胞内、周质空间及胞外粗酶液进行乙草胺的降解研究,结果表明24h的乙草胺降解率分别为17.43%、18.34%、44.95%,乙草胺降解酶主要来自复合菌的胞外酶,而胞内也存在少量的降解酶。当用乙·苄复配剂(20mg/L苄嘧磺隆和60mg/L乙草胺)胁迫敏感菌-大肠杆菌和枯草芽孢杆菌后,SOD酶活迅速下降,至处理后2h达到最低值;之后回升至处理后12h到达最高值,SOD酶活分别为处理前1.63倍和1.08倍。而大肠杆菌的C AT酶活曲线显示出两个峰值,最大值为处理前的1.23倍;枯草芽孢杆菌的CAT酶活在处理初期变化缓慢,处理18h时达到最高值,此时酶活为处理前的4.20倍。总体上,G-菌-大肠杆菌、G+菌-枯草芽孢杆菌经低浓度乙·苄复配剂胁迫后,可缓慢通过SOD酶和CAT酶的提高对抗氧化胁迫。而超过该浓度后,两菌株的CAT酶活显著降低,SOD酶活不变,表明高于60mg/L乙草胺及20mg/L苄嘧磺隆对敏感菌株造成损害。
[Abstract]:Acetochlor, bensulfuron-methyl and acetylbensulfuron-methyl are the most widely used herbicides in paddy fields. However, a large amount of application caused obvious pesticide damage to the next crop and caused serious pollution to the ecological environment of farmland. The residues of herbicides in soil are generally disappeared through physical, chemical and biological processes, in which microbial degradation is the main pathway. Therefore, the use of degradation microorganisms to eliminate environmental pollution is of great significance. Through enrichment culture, a compound strain 66C, which can use Acetochlor as the sole carbon source and tolerance to bensulfuron-methyl, was selected. Four bacterial strains were isolated from 66C complex strain and named 66C-1O66C-2O66C-3O66C-4 respectively. The strains were identified by morphological characteristics, molecular phylogenetic analysis and physiological and biochemical analysis. 66C-1A66C-2O66C-3O66C-4 was identified as Pseudomonas, Psedomona shunanensi s, and Pseudomonas pseudomonas was nitrified. A single strain could not degrade Acetochlor, and only when the four strains were mixed with 1: 1: 1: 1: 1, could they grow, so that the co-degradation of Acetochlor could be achieved. The four strains with the same proportion were renamed HXDW.. When the initial concentration of Acetochlor was 100 mg 路L ~ (-1), pH 9.0% NaCl concentration was 2%, the mixed bacteria HXDW grew best at 25 鈩，
本文编号：2360008
[Abstract]:Acetochlor, bensulfuron-methyl and acetylbensulfuron-methyl are the most widely used herbicides in paddy fields. However, a large amount of application caused obvious pesticide damage to the next crop and caused serious pollution to the ecological environment of farmland. The residues of herbicides in soil are generally disappeared through physical, chemical and biological processes, in which microbial degradation is the main pathway. Therefore, the use of degradation microorganisms to eliminate environmental pollution is of great significance. Through enrichment culture, a compound strain 66C, which can use Acetochlor as the sole carbon source and tolerance to bensulfuron-methyl, was selected. Four bacterial strains were isolated from 66C complex strain and named 66C-1O66C-2O66C-3O66C-4 respectively. The strains were identified by morphological characteristics, molecular phylogenetic analysis and physiological and biochemical analysis. 66C-1A66C-2O66C-3O66C-4 was identified as Pseudomonas, Psedomona shunanensi s, and Pseudomonas pseudomonas was nitrified. A single strain could not degrade Acetochlor, and only when the four strains were mixed with 1: 1: 1: 1: 1, could they grow, so that the co-degradation of Acetochlor could be achieved. The four strains with the same proportion were renamed HXDW.. When the initial concentration of Acetochlor was 100 mg 路L ~ (-1), pH 9.0% NaCl concentration was 2%, the mixed bacteria HXDW grew best at 25 鈩，
本文编号：2360008
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