College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China.
The Management Center of Wuyanling National Natural Reserve in Zhejiang, Wenzhou 325500, China.
J Hazard Mater. 2024 Mar 5;465:133242. doi: 10.1016/j.jhazmat.2023.133242. Epub 2023 Dec 14.
The resuscitated strains achieved through the addition of resuscitation promoting factor (Rpf) hold significant promise as bio-inoculants for enhancing the bioremediation of polychlorinated biphenyls (PCBs). Nevertheless, the potential of these resuscitated strains to transition into a viable but non-culturable (VBNC) state, along with the specific stressors that initiate this transformation, remains to be comprehensively elucidated. In this study, a resuscitated strain HR2, obtained through Rpf amendment, was employed to investigate its survival strategies under combined stress involving low temperature (LT), and PCBs, in the absence and presence of heavy metals (HMs). Whole-genome analysis demonstrated that HR2, affiliated with Achromobacter, possessed 107 genes associated with the degradation of polycyclic aromatic compounds. Remarkably, HR2 exhibited effective degradation of Aroclor 1242 and robust resistance to stress induced by LT and PCBs, while maintaining its culturability. However, when exposed to the combined stress of LT, PCBs, and HMs, HR2 entered the VBNC state. This state was characterized by significant decreases in enzyme activities and notable morphological, physiological, and molecular alterations compared to normal cells. These findings uncovered the survival status of resuscitated strains under stressful conditions, thereby offering valuable insights for the development of effective bioremediation strategies.
通过添加复苏促进因子 (Rpf) 获得的复苏菌株有望成为生物接种剂，以增强多氯联苯 (PCBs) 的生物修复。然而，这些复苏菌株转变为存活但非可培养 (VBNC) 状态的潜力，以及引发这种转变的特定胁迫因素，仍需要全面阐明。在这项研究中，使用通过 Rpf 修饰获得的复苏菌株 HR2 来研究其在低温 (LT) 和 PCBs 联合胁迫下的生存策略，而不存在和存在重金属 (HM) 时。全基因组分析表明，HR2 属于无色杆菌，拥有 107 个与多环芳烃化合物降解有关的基因。值得注意的是，HR2 表现出对 Aroclor 1242 的有效降解和对 LT 和 PCBs 诱导的应激的强大抗性，同时保持其可培养性。然而，当暴露于 LT、PCBs 和 HMs 的联合胁迫下时，HR2 进入了 VBNC 状态。与正常细胞相比，这种状态的特征是酶活性显著下降，以及明显的形态、生理和分子改变。这些发现揭示了复苏菌株在应激条件下的生存状态，为开发有效的生物修复策略提供了有价值的见解。
