Biofilms of the non-tuberculous Mycobacterium chelonae form an extracellular matrix and display distinct expression patterns

Perla Vega-Dominguez; Eliza Peterson; Min Pan; Alessandro Di Maio; Saumya Singh; Siva Umapathy; Deepak K Saini; Nitin Baliga; Apoorva Bhatt

doi:10.1016/j.tcsw.2020.100043

Biofilms of the non-tuberculous Mycobacterium chelonae form an extracellular matrix and display distinct expression patterns

Cell Surf. 2020 Aug 5:6:100043. doi: 10.1016/j.tcsw.2020.100043. eCollection 2020 Dec.

Authors

Perla Vega-Dominguez¹, Eliza Peterson², Min Pan², Alessandro Di Maio¹, Saumya Singh³, Siva Umapathy³, Deepak K Saini⁴, Nitin Baliga², Apoorva Bhatt¹

Affiliations

¹ School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
² Institute for Systems Biology, Seattle, WA 98109, USA.
³ Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
⁴ Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India.

Abstract

Mycobacterium chelonae is an environmental, non-tuberculous mycobacterial species, capable of causing infections in humans. Biofilm formation is a key strategy used by M. chelonae in colonising niches in the environment and in the host. We studied a water-air interface (pellicle) biofilm of M. chelonae using a wide array of approaches to outline the molecular structure and composition of the biofilm. Scanning electron micrographs showed that M. chelonae biofilms produced an extracellular matrix. Using a combination of biochemical analysis, Raman spectroscopy, and fluorescence microscopy, we showed the matrix to consist of proteins, carbohydrates, lipids and eDNA. Glucose was the predominant sugar present in the biofilm matrix, and its relative abundance decreased in late (established) biofilms. RNA-seq analysis of the biofilms showed upregulation of genes involved in redox metabolism. Additionally, genes involved in mycolic acid, other lipid and glyoxylate metabolism were also upregulated in the early biofilms.

Keywords: Biofilms; DEG, Differentially expressed genes; ECM, Extracellular matrix; Extracellular matrix; FMA, Free mycolic acids; Lipids; Mycobacterium chelonae; NTMs, Non-tuberculous mycobacteria; Non-tuberculous mycobacteria; PG, Phosphatidyl glycerol; Raman spectroscopy; SEM, Scanning electron microscopy; TDM, Trehalose dimycolate; eDNA, Extra cellular DNA.

Abstract

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