Unraveling the metabolism of Mycobacterium caprae using comparative genomics. (September 2022)

• Record Type: Journal Article
• Authors: Romano, Giovanni Emiddio; Silva-Pereira, Taiana Tainá; de Melo, Filipe Menegatti; Sisco, Maria Carolina; Banari, Alexandre Campos; Zimpel, Cristina Kraemer; Soler-Camargo, Naila Cristina; Guimarães, Ana Marcia de Sá
• Is Part Of: Tuberculosis. Volume 136(2022)
• Publication Date: 2022-09
• Subjects: Mycobacterium caprae -- Metabolism -- Genomics -- Mycobacterium tuberculosis complex; 616.995
• DOI: 10.1016/j.tube.2022.102254
• Languages: English
• ISSNs: 1472-9792

Abstract

Abstract: In our laboratory, Mycobacterium caprae has poor growth in standard medium (SM) 7H9-OADC supplemented with pyruvate and Tween-80. Our objectives were to identify mutations affecting M. caprae metabolism and use this information to design a culture medium to improve its growth. We selected 77 M. caprae genomes and sequenced M. caprae NLA000201913 used in our experiments. Mutations present in >95% of the strains compared to Mycobacterium tuberculosis H37Rv were analyzed in silico for their deleterious effects on proteins of metabolic pathways. Apart from the known defect in the pyruvate kinase, M. caprae has important lesions in enzymes of the TCA cycle, methylmalonyl cycle, B12 metabolism, and electron-transport chain. We provide evidence of enzymatic redundancy elimination and epistatic mutations, and possible production of toxic metabolites hindering M. caprae growth in vitro . A newly designed SM supplemented with l -glutamate allowed faster growth and increased final microbial mass of M. caprae . However, possible accumulation of metabolic waste-products and/or nutritional limitations halted M. caprae growth prior to a M. tuberculosis -like stationary phase. Our findings suggest that M. caprae relies on GABA and/or glyoxylate shunts for in vitro growth in routine media . The newly developed medium will improve experiments with this bacterium by allowing faster growth in vitro . Highlights: Members of the Mycobacterium tuberculosis complex occupy distinct ecological niches that determine their metabolic features. Mycobacterium caprae has poor growth in standard culture medium compared to M. tuberculosis, hampering the research Results suggest M. caprae eliminated redundant enzymes and depends on GABA and/or glyoxylate shunts for in vitro growth. Growth halt of M. caprae is due to metabolic waste-products or nutrient limitation resulting from lesions in the metabolism A newly designed culture medium increased the replication rate of M. caprae.