Dimethyl phthalate destroys the cell membrane structural integrity of Pseudomonas fluorescens

Wenjing Chen; Ruxin Guo; Zhigang Wang; Weihui Xu; Yunlong Hu

doi:10.3389/fmicb.2022.949590

Dimethyl phthalate destroys the cell membrane structural integrity of Pseudomonas fluorescens

Front Microbiol. 2022 Aug 22:13:949590. doi: 10.3389/fmicb.2022.949590. eCollection 2022.

Authors

Wenjing Chen^{1

2

3}, Ruxin Guo^{1

2}, Zhigang Wang^{1

2}, Weihui Xu^{1

2}, Yunlong Hu^{1

2}

Affiliations

¹ College of Life Sciences, Agriculture and Forestry, Qiqihar University, Qiqihar, China.
² Heilongjiang Provincial Technology Innovation Center of Agromicrobial Preparation Industrialization, Qiqihar, China.
³ Center for Ecological Research, Northeast Forestry University, Harbin, China.

Abstract

A Gram-negative bacteria (Pseudomonas fluorescens) was exposed to different concentrations (0, 20, and 40 mg/L) of dimethyl phthalate (DMP) for 8 h, and then Fourier transform infrared spectroscopy (FTIR) analysis, lipopolysaccharide content detection, analysis of fatty acids, calcein release test, proteomics, non-targeted metabolomics, and enzyme activity assays were used to evaluate the toxicological effect of DMP on P. fluorescens. The results showed that DMP exposure caused an increase in the unsaturated fatty acid/saturated fatty acid (UFA/SFA) ratio and in the release of lipopolysaccharides (LPSs) from the cell outer membrane (OM) of P. fluorescens. Moreover, DMP regulated the abundances of phosphatidyl ethanolamine (PE) and phosphatidyl glycerol (PG) of P. fluorescens and induced dye leakage from an artificial membrane. Additionally, excessive reactive oxygen species (ROS), malondialdehyde (MDA), and changes in antioxidant enzymes (i.e., catalase [CAT] and superoxide dismutase [SOD]) activities, as well as the inhibition of Ca²⁺-Mg²⁺-ATPase and Na⁺/K⁺-ATPase activities in P. fluorescens, which were induced by the DMP. In summary, DMP could disrupt the lipid asymmetry of the outer membrane, increase the fluidity of the cell membrane, and destroy the integrity of the cell membrane of P. fluorescens through lipid peroxidation, oxidative stress, and ion imbalance.

Keywords: Pseudomonas fluorescens; cell micro-interface; dimethyl phthalate; oxidative stress; toxicological effect.