Alterations in the Cell Wall of Rhodococcus biphenylivorans Under Norfloxacin Stress

Yangyang Jia; Chungui Yu; Jiahui Fan; Yulong Fu; Zhe Ye; Xiaoguang Guo; Ying Xu; Chaofeng Shen

doi:10.3389/fmicb.2020.554957

Alterations in the Cell Wall of Rhodococcus biphenylivorans Under Norfloxacin Stress

Front Microbiol. 2020 Oct 6:11:554957. doi: 10.3389/fmicb.2020.554957. eCollection 2020.

Authors

Yangyang Jia¹, Chungui Yu¹, Jiahui Fan¹, Yulong Fu¹, Zhe Ye¹, Xiaoguang Guo¹, Ying Xu², Chaofeng Shen^{1

3}

Affiliations

¹ Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
² State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
³ Zhejiang Provincial Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, China.

Abstract

Many microorganisms can enter a viable but non-culturable (VBNC) state under various environmental stresses, while they can also resuscitate when the surroundings turn to suitable conditions. Cell walls play a vital role in maintaining cellular integrity and protecting cells from ambient threats. Here, we investigated the alterations in the cell wall of Rhodococcus biphenylivorans TG9 at VBNC state under norfloxacin stress and then at resuscitated state in fresh lysogeny broth medium. Electron microscopy analyses presented that TG9 in the VBNC state had a thicker and rougher cell wall than that in exponential phase or resuscitated state. Meanwhile, the results from infrared spectroscopy also showed that its VBNC state has different peptidoglycan structures in the cell wall. Moreover, in the VBNC cells the gene expressions related to cell wall synthesis and remodeling maintain a relatively high level. It indicates that the morphological variations of TG9 at the VBNC state might result from kinetic changes in the cell wall synthesis and remodeling. As a consequence, the alterations in the cell wall of VBNC TG9 may somewhat account for its tolerance mechanisms to antibiotic treatment.

Keywords: Rhodococcus biphenylivorans; cell wall; environmental stresses; peptidoglycan; resuscitation; viable but non-culturable state.