Cell Biology


Publications (77)

Indications for a genetic basis for big bacteria and description of the giant cable bacterium Candidatus Electrothrix gigas sp. nov

Citation
Geelhoed et al. (2023). Microbiology Spectrum
Names (2)
Ca. Electrothrix gigas Ca. Electrothrix
Subjects
Cell Biology Ecology General Immunology and Microbiology Genetics Infectious Diseases Microbiology (medical) Physiology
Abstract
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, with filament diameters ranging from 0.4 to 8 µm. 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.

Pathogenicity and Transcriptomic Analyses of Two “ Candidatus Liberibacter asiaticus” Strains Harboring Different Types of Phages

Citation
Zheng et al. (2023). Microbiology Spectrum 11 (3)
Names (1)
Ca. Liberibacter asiaticus
Subjects
Cell Biology Ecology General Immunology and Microbiology Genetics Infectious Diseases Microbiology (medical) Physiology
Abstract
Citrus Huanglongbing (HLB), also called citrus greening disease, is a highly destructive disease threatening citrus production worldwide. “ Candidatus Liberibacter asiaticus” is one of the most common putative causal agents of HLB. Phages of “ Ca . Liberibacter asiaticus”

Candidatus Alkanophaga archaea from Guaymas Basin hydrothermal vent sediment oxidize petroleum alkanes

Citation
Zehnle et al. (2023). Nature Microbiology 8 (7)
Names (3)
Ca. Thermodesulfobacterium syntrophicum Ca. Syntrophoarchaeum Ca. Alkanophaga
Subjects
Applied Microbiology and Biotechnology Cell Biology Genetics Immunology Microbiology Microbiology (medical)
Abstract
AbstractMethanogenic and methanotrophic archaea produce and consume the greenhouse gas methane, respectively, using the reversible enzyme methyl-coenzyme M reductase (Mcr). Recently, Mcr variants that can activate multicarbon alkanes have been recovered from archaeal enrichment cultures. These enzymes, called alkyl-coenzyme M reductase (Acrs), are widespread in the environment but remain poorly understood. Here we produced anoxic cultures degrading mid-chain petroleum n-alkanes between pentane (C5) and tetradecane (C14) at 70 °C using oil-rich Guaymas Basin sediments. In these cultures, archaea of the genus Candidatus Alkanophaga activate the alkanes with Acrs and completely oxidize the alkyl groups to CO2. Ca. Alkanophaga form a deep-branching sister clade to the methanotrophs ANME-1 and are closely related to the short-chain alkane oxidizers Ca. Syntrophoarchaeum. Incapable of sulfate reduction, Ca. Alkanophaga shuttle electrons released from alkane oxidation to the sulfate-reducing Ca. Thermodesulfobacterium syntrophicum. These syntrophic consortia are potential key players in petroleum degradation in heated oil reservoirs.

Environmental Factors Affect the Bacterial Community in Diaphorina citri , an Important Vector of “ Candidatus Liberibacter asiaticus”

Citation
Jiang et al. (2023). Microbiology Spectrum 11 (2)
Names (1)
Ca. Liberibacter asiaticus
Subjects
Cell Biology Ecology General Immunology and Microbiology Genetics Infectious Diseases Microbiology (medical) Physiology
Abstract
The Asian citrus psyllid (ACP) is an important vector of the HLB pathogen, which is a major threat to citrus production around the world. Bacterial communities harbored by insects could be affected by different environmental factors.