Microbiology Laboratory, Department of Biotechnology & Bioinformatics, North-Eastern Hill University, Umshing, Shillong, Meghalaya 793022, India.
J Microbiol. 2011 Aug;49(4):568-74. doi: 10.1007/s12275-011-0366-0. Epub 2011 Sep 2.
Enrichment-based methods targeted at uranium-tolerant populations among the culturable, aerobic, chemo-heterotrophic bacteria from the subsurface soils of Domiasiat (India's largest sandstone-type uranium deposits, containing an average ore grade of 0.1 % U(3)O(8)), indicated a wide occurrence of Serratia marcescens. Five representative S. marcescens isolates were characterized by a polyphasic taxonomic approach. The phylogenetic analyses of 16S rRNA gene sequences showed their relatedness to S. marcescens ATCC 13880 (≥99.4% similarity). Biochemical characteristics and random amplified polymorphic DNA profiles revealed significant differences among the representative isolates and the type strain as well. The minimum inhibitory concentration for uranium U(VI) exhibited by these natural isolates was found to range from 3.5-4.0 mM. On evaluation for their uranyl adsorption properties, it was found that all these isolates were able to remove nearly 90-92% (21-22 mg/L) and 60-70% (285-335 mg/L) of U(VI) on being challenged with 100 μM (23.8 mg/L) and 2 mM (476 mg/L) uranyl nitrate solutions, respectively, at pH 3.5 within 10 min of exposure. his capacity was retained by the isolates even after 24 h of incubation. Viability tests confirmed the tolerance of these isolates to toxic concentrations of soluble uranium U(VI) at pH 3.5. This is among the first studies to report uranium-tolerant aerobic chemoheterotrophs obtained from the pristine uranium ore-bearing site of Domiasiat.
基于富集的方法，针对可培养的、好氧的、化能异养细菌中耐铀种群进行了研究，这些细菌来自多马西亚特（印度最大的砂岩型铀矿床，铀矿石品位平均为 0.1%U3O8）的地下土壤。结果表明，广泛存在粘质沙雷氏菌。通过多相分类方法对 5 个代表性的粘质沙雷氏菌分离株进行了表征。16S rRNA 基因序列的系统发育分析表明，它们与粘质沙雷氏菌 ATCC 13880（≥99.4%相似度）具有密切的亲缘关系。生化特征和随机扩增多态性 DNA 图谱显示，代表分离株与模式株之间存在显著差异。这些天然分离株对铀 U(VI)的最小抑制浓度被发现范围在 3.5-4.0 mM 之间。在评估它们对铀酰的吸附特性时，发现所有这些分离株都能够在 pH 值为 3.5 时，在 10 分钟内分别去除 100 μM（23.8 mg/L）和 2 mM（476 mg/L）的铀酰硝酸盐溶液中的近 90-92%（21-22 mg/L）和 60-70%（285-335 mg/L）的铀（VI）。这种能力在 24 小时的孵育后仍能保留。生存能力测试证实了这些分离株对 pH 值为 3.5 时可溶性铀 U(VI)的毒性浓度的耐受性。这是首次报道从多马西亚特原始含铀矿石产地获得的耐铀好氧化能异养菌的研究之一。
