Department of Genetics, Faculty of Agriculture, Cairo University, Giza, 12613, Egypt.
Biotechnology Department, Faculty of Agriculture, Al-Azhar University, Cairo, Egypt.
Funct Integr Genomics. 2024 Sep 25;24(5):174. doi: 10.1007/s10142-024-01441-9.
Many organisms have adapted to survive in environments with high levels of arsenic (As), a naturally occurring metalloid with various oxidation states and a common element in human activities. These organisms employ diverse mechanisms to resist the harmful effects of arsenic compounds. Ten arsenic-resistant bacteria were isolated from contaminated wastewater in this study. The most efficient bacterial isolate able to resist 15,000 ppm NaHAsO·7HO was identified using the 16S rRNA gene and whole genome analysis as Enterobacter cloacae FACU. The arsenic E. cloacae FACU biosorption capability was analyzed. To further unravel the genetic determinants of As stress resistance, the whole genome sequence of E. cloacae FACU was performed. The FACU complete genome sequence consists of one chromosome (5.7 Mb) and two plasmids, pENCL 1 and pENCL 2 (755,058 and 1155666 bp, respectively). 7152 CDSs were identified in the E. cloacae FACU genome. The genome consists of 130 genes for tRNA and 21 for rRNAs. The average G + C content was found to be 54%. Sequencing analysis annotated 58 genes related to resistance to many heavy metals, including 16 genes involved in arsenic efflux transporter and arsenic reduction (five arsRDABC genes) and 42 genes related to lead, zinc, mercury, nickel, silver, copper, cadmium and chromium in FACU. Scanning electron microscopy (SEM) confirmed the difference between the morphological responses of the As-treated FACU compared to the control strain. The study highlights the genes involved in the mechanism of As stress resistance, metabolic pathways, and potential activity of E. cloacae FACU at the genetic level.
许多生物已经适应了在高砷环境中生存，砷是一种具有多种氧化态的天然类金属，也是人类活动中的常见元素。这些生物采用了多种机制来抵抗砷化合物的有害影响。本研究从受污染废水中分离出 10 株耐砷细菌。使用 16S rRNA 基因和全基因组分析，从这些细菌中鉴定出一种最有效的细菌分离株，即能够耐受 15000ppm NaHAsO·7HO 的阴沟肠杆菌 FACU。分析了砷抗性肠杆菌 FACU 的生物吸附能力。为了进一步揭示砷胁迫抗性的遗传决定因素，对肠杆菌 FACU 的全基因组序列进行了分析。FACU 的完整基因组序列由一条染色体（5.7Mb）和两个质粒 pENCL 1 和 pENCL 2（分别为 755058bp 和 1155666bp）组成。在肠杆菌 FACU 基因组中鉴定出 7152 个 CDS。基因组包含 130 个 tRNA 基因和 21 个 rRNA 基因。平均 G+C 含量为 54%。测序分析注释了 58 个与多种重金属抗性相关的基因，包括 16 个参与砷外排转运体和砷还原（五个 arsRDABC 基因）以及 42 个与铅、锌、汞、镍、银、铜、镉和铬相关的基因。扫描电子显微镜（SEM）证实了砷处理的 FACU 与对照菌株之间形态响应的差异。该研究强调了参与砷胁迫抗性机制、代谢途径以及肠杆菌 FACU 遗传水平潜在活性的相关基因。
