Publication
Title
Indications for a genetic basis for big bacteria and description of the giant cable bacterium **Candidatus Electrothrix gigas sp. nov.**
Author
Abstract
Bacterial cells can vary greatly in size, from a few hundred nanometers to hundreds of micrometers in diameter. Filamentous cable bacteria also display substantial size differences,differences, with filament diameters ranging from 0.4 to 8 mu m. We analyzed diameters ranging from 0.4 to 8 mu m. We analyzed the genomes of cable bacterium filaments from 11 coastal environments of which the resulting 23 new genomes represent 10 novel species-level clades of Candidatus Electrothrix and two clades that putatively represent novel genus-level diversity. Fluorescence in situ hybridization with a species-level probe showed that large-sized cable bacteria belong to a novel species with the proposed name Ca. Electrothrix gigas. Comparative genome analysis suggests genes that play a role in the construction or functioning of large cable bacteria cells: the genomes of Ca. Electrothrix gigas encode a novel actin-like protein as well as a species-specific gene cluster encoding four putative pilin proteins and a putative type II secretion platform protein, which are not present in other cable bacteria. The novel actin-like protein was also found in a number of other giant bacteria, suggesting there could be a genetic basis for large cell size. This actin-like protein (denoted big bacteria protein, Bbp) may have a function analogous to other actin proteins in cell structure or intracellular transport. We contend that Bbp may help overcome the challenges of diffusion limitation and/or morphological complexity presented by the large cells of Ca. Electrothrix gigas and other giant bacteria. IMPORTANCE In this study, we substantially expand the known diversity of marine cable bacteria and describe cable bacteria with a large diameter as a novel species with the proposed name Candidatus Electrothrix gigas. In the genomes of this species, we identified a gene that encodes a novel actin-like protein [denoted big bacteria protein (Bbp)]. The bbp gene was also found in a number of other giant bacteria, predominantly affiliated to Desulfobacterota and Gammaproteobacteria, indicating that there may be a genetic basis for large cell size. Thus far, mostly structural adaptations of giant bacteria, vacuoles, and other inclusions or organelles have been observed, which are employed to overcome nutrient diffusion limitation in their environment. In analogy to other actin proteins, Bbp could fulfill a structural role in the cell or potentially facilitate intracellular transport.
Language
English
Source (journal)
Microbiology spectrum. - Washington, DC, 2013, currens
Publication
Washington, DC : ASM Press , 2023
ISSN
2165-0497
DOI
10.1128/SPECTRUM.00538-23
Volume/pages
11 :5 (2023) , p. 1-20
Article Reference
e0053823
e00538-23
ISI
001107303900022
Pubmed ID
37732806
Medium
E-only publicatie
Full text (Publisher's DOI)
Full text (open access)
UAntwerpen
Faculty/Department
Research group
Project info
SEDBIOGEOCHEM 2.0: Hardwiring the ocean floor: the impact of microbial electrical circuitry on biogeochemical cycling in marine sediments
COULOMBUS: Electric Currents in Sediment and Soil
Biogeochemical cycling, redox transformations and microbial actors in electrified sediment ecosystems.
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identifier
Creation 30.10.2023
Last edited 25.04.2024
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