Learman Deric R, Ahmad Zahra, Brookshier Allison, Henson Michael W, Hewitt Victoria, Lis Amanda, Morrison Cody, Robinson Autumn, Todaro Emily, Wologo Ethan, Wynne Sydney, Alm Elizabeth W, Kourtev Peter S
Institute for Great Lakes Research and Department of Biology, Central Michigan University, Mount Pleasant, MI, USA.
PeerJ. 2019 Jan 14;6:e6258. doi: 10.7717/peerj.6258. eCollection 2019.
A total of 16 different strains of spp. were isolated from contaminated soil and enriched on the carcinogen, hexavalent chromium [Cr(VI)]. The majority of the isolates (11 of the 16) were able to tolerate concentrations (0.1 mM) of cobalt, cadmium, and nickel, in addition to Cr(VI) (0.5-20 mM). Interestingly, these bacteria were also able to tolerate three different antibiotics (ranges: ampicillin 0-16 μg ml, chloramphenicol 0-24 μg ml, and vancomycin 0-24 μg ml). To gain genetic insight into these tolerance pathways, the genomes of these isolates were assembled and annotated. The genomes of these isolates not only have some shared genes (core genome) but also have a large amount of variability. The genomes also contained an annotated Cr(VI) reductase () that could be related to Cr(VI) reduction. Further, various heavy metal tolerance (e.g., Co/Zn/Cd efflux system) and antibiotic resistance genes were identified, which provide insight into the isolates' ability to tolerate metals and antibiotics. Overall, these isolates showed a wide range of tolerances to heavy metals and antibiotics and genetic diversity, which was likely required of this population to thrive in a contaminated environment.
总共从受污染土壤中分离出16种不同的 spp. 菌株，并在致癌物六价铬[Cr(VI)]上进行富集培养。大多数分离菌株（16株中的11株）除了能耐受Cr(VI)（0.5 - 20 mM）外，还能耐受钴、镉和镍的浓度（0.1 mM）。有趣的是，这些细菌还能耐受三种不同的抗生素（范围：氨苄青霉素0 - 16 μg/ml、氯霉素0 - 24 μg/ml和万古霉素0 - 24 μg/ml）。为了深入了解这些耐受途径的遗传学机制，对这些分离菌株的基因组进行了组装和注释。这些分离菌株的基因组不仅有一些共同的基因（核心基因组），而且具有大量的变异性。这些基因组还包含一个已注释的Cr(VI)还原酶（），可能与Cr(VI)的还原有关。此外，还鉴定出了各种重金属耐受性（如Co/Zn/Cd外排系统）和抗生素抗性基因，这有助于了解分离菌株耐受金属和抗生素的能力。总体而言，这些分离菌株对重金属和抗生素表现出广泛的耐受性以及遗传多样性，这可能是该菌群在污染环境中生存所必需的。
