Cited by 79Bacterial Genetics and BiotechnologyEscherichia coli research studiesLegume Nitrogen Fixing Symbiosis

The DOI matches its Crossref record; 49 of the 49 references it cites were found in a registry or an index.

Function of a Chemotaxis-Like Signal Transduction Pathway in Modulating Motility, Cell Clumping, and Cell Length in the Alphaproteobacterium Azospirillum brasilense

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Abstract

A chemotaxis signal transduction pathway (hereafter called Che1) has been previously identified in the alphaproteobacterium Azospirillum brasilense. Previous experiments have demonstrated that although mutants lacking CheB and/or CheR homologs from this pathway are defective in chemotaxis, a mutant in which the entire chemotaxis pathway has been mutated displayed a chemotaxis phenotype mostly similar to that of the parent strain, suggesting that the primary function of this Che1 pathway is not the control of motility behavior. Here, we report that mutants carrying defined mutations in the cheA1 (strain AB101) and the cheY1 (strain AB102) genes and a newly constructed mutant lacking the entire operon [Delta(cheA1-cheR1)::Cm] (strain AB103) were defective, but not null, for chemotaxis and aerotaxis and had a minor defect in swimming pattern. We found that mutations in genes of the Che1 pathway affected the cell length of actively growing cells but not their growth rate. Cells of a mutant lacking functional cheB1 and cheR1 genes (strain BS104) were significantly longer than wild-type cells, whereas cells of mutants impaired in the cheA1 or cheY1 genes, as well as a mutant lacking a functional Che1 pathway, were significantly shorter than wild-type cells. Both the modest chemotaxis defects and the observed differences in cell length could be complemented by expressing the wild-type genes from a plasmid. In addition, under conditions of high aeration, cells of mutants lacking functional cheA1 or cheY1 genes or the Che1 operon formed clumps due to cell-to-cell aggregation, whereas the mutant lacking functional CheB1 and CheR1 (BS104) clumped poorly, if at all. Further analysis suggested that the nature of the exopolysaccharide produced, rather than the amount, may be involved in this behavior. Interestingly, mutants that displayed clumping behavior (lacking cheA1 or cheY1 genes or the Che1 operon) also flocculated earlier and quantitatively more than the wild-type cells, whereas the mutant lacking both CheB1 and CheR1 was delayed in flocculation. We propose that the Che1 chemotaxis-like pathway modulates the cell length as well as clumping behavior, suggesting a link between these two processes. Our data are consistent with a model in which the function of the Che1 pathway in regulating these cellular functions directly affects flocculation, a cellular differentiation process initiated under conditions of nutritional imbalance.

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Crossref · 10.1128/jb.00734-08

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  • Chemotaxis plays a role in the autoaggregation of Azospirillum brasiliense; the Che1 chemotactic signal transduction pathway increases swimming velocity with changes in aeration conditions, and mutants defective in Che1 do not alter their swimming speed and do not detach from early, reversibly formed clumps, leading to formation of larger flocs stabilised by exopolysaccharides.

    “Chemotaxis also plays a role in the autoaggregation of Azospirillum brasiliense, a plant-associated soil bacterium [99]. Here, the chemotactic signal transduction pathway Che1 increases swimming velocity with changes in aeration conditions; mutants defective in Che1 do not alter their swimming speed and do not detach from early, reversibly formed clumps. This in turn leads to formation of larger fl”

    From Bacterial autoaggregation (2018) · cites this paper as [99]

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Metadata

Authors
Bible, A. N., Stephens, B. B., Ortega, D. R., Xie, Z., & Alexandre, G.
Affiliations
  • Department of Biochemistry, Cellular and Molecular Biology
  • Georgia State University (US)
  • University of Tennessee at Knoxville (US)
Corresponding author
Alexandre, Gladys
Venue
Journal of Bacteriology
Published
2008-10
Volume
190
Issue
19
Pages
6365-6375
ISSN
  • 0021-9193 (ISSN-L)
  • 1098-5530
OpenAlex
W1991537109
Cited by
79
References
49
Citations by year
2026: 4 · 2025: 2 · 2024: 2 · 2023: 3 · 2022: 2 · 2021: 6 · 2020: 1 · 2019: 3 · 2018: 4 · 2017: 4 · 2016: 4 · 2015: 6 · 2014: 7 · 2013: 5 · 2012: 6
FWCI
3.80
Type
journal article
Language
en
Open access
Locations
  • Journal of Bacteriology (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Bacterial Genetics and Biotechnology
  • Life Sciences › Immunology and Microbiology › Microbiology › Escherichia coli research studies
  • Life Sciences › Agricultural and Biological Sciences › Plant Science › Legume Nitrogen Fixing Symbiosis
Keywords
Azospirillum brasilense, cell clumping, flocculation, exopolysaccharides, aerotaxis, swimming patterns, CheA, CheY, Cheb, Cher, bacterial motility, gene complementation, Alphaproteobacteria
MeSH terms
Bacterial Proteins, Chemotaxis, Genetic Complementation Test, Models, Genetic, Operon, Signal Transduction, Azospirillum brasilense, Gene Expression Regulation, Bacterial

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