类球红细菌XR12的分离、鉴定及其解毒效果研究

为丰富敌百虫污染治理的微生物资源, 从养殖污泥中分离筛选了一株优良的敌百虫耐受菌XR12, 综合生理生化特性与16S rRNA序列分析对其进行了鉴定, 采用纸片扩散法分析了其耐药性, 并进一步评价了其安全性与解毒效果。结果显示: 菌株XR12对敌百虫的最大耐受浓度达到了7680 mg/L。通过生理生化特性以及16S rRNA序列分析, 菌株XR12被鉴定为类球红细菌(Rhodobacter sphaeroides), 其16S rRNA序列与GenBank中类球红细菌菌株的16S rRNA序列有98%—100%的同源性, 而且与类球红细菌菌株RSF1 (登录号: KF606891)的亲缘关系最近。此外, 菌株XR12对卡那霉素、罗红霉素、吡哌酸、阿莫西林、氟苯尼考、多黏菌素B、新霉素、庆大霉素、氧氟沙星、恩诺沙星、诺氟沙星、链霉素、四环素、奈替米星等抗生素高度敏感, 对多西环素中度敏感, 对杆菌肽、萘啶酸、磺胺异噁唑等抗生素耐药, 对斑马鱼的LC₅₀大于109 cfu/mL, 能够将敌百虫对斑马鱼的LC₅₀从26.06 mg/L增加至59.51 mg/L, 对敌百虫具有良好的解毒效果。研究证实了类球红细菌XR12的安全性及其对敌百虫良好的解毒效果, 对养殖水体中敌百虫的解毒具有潜在的应用价值。

ISOLATION,IDENTIFICATION AND DETOXIFICATION OF A TRICHLORPHON-TOLERANT RHODOBACTERSPHAEROIDES XR12

To explore the microbial resources on control trichlorphon pollution, a potential trichlorphon-tolerant bacterium XR12 was isolated and screened from the aquaculture sediment according to the physiological-biochemical characteristics and 16S rRNA gene sequence analysis, and its antibiotic resistance and its safety and detoxification effect were evaluated. The results indicated that strain XR12 exhibited the maximum tolerance concentration of 7680 mg/L trichlorphon. The strain XR12 was identified as Rhodobacter sphaeroides through phenotypic characterization and phylogenetic analysis based on 16S rRNA sequences. Its 16S rRNA sequence had homology of 98%—100% with strains of R. sphaeroides from GenBank, and showed the closest relation to R. sphaeroides strain RSF1 (GenBank accession number: KF606891). In addition, XR12 exhibited high sensitivity to kanamycin, roxithromycin, pipram, amoxicillin, florfenicol, polymyxin B, neomycin, gentamycin, ofloxacin, enrofloxacin, norfloxacin, streptomycin, tetracycline, netilmicin, intermediate sensitivity to doxycycline and resistance to bacitracin, nalidixic acid and sulfamethoxazole. XR12 had a LC₅₀ of >109 cfu/mL for zebra fish, and could significantly enhance the LC₅₀ of trichlorfon to zebrafish from 26.06 to 59.51 mg/L, indicating a good detoxification effect on trichlorfon. This study indicated that XR12 had the potential for trichlorfon detoxification in aquaculture water.