<i>Haemophilus</i>
            spills its guts to make a biofilm

Seifert, H. Steven

doi:10.1073/pnas.1711077114

Cited by 3 publications

(2 citation statements)

References 13 publications

(15 reference statements)

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“…This may lead to increased cellular adhesion, similar to what is observed in the xopQ- mutant. Furthermore, the KEGG analysis revealed components of type IV secretion system to be up-regulated in the xopQ- mutant and previous results indicate this secretion system is involved in promoting biofilm formation (Cenens, Andrade et al, 2020, Elhenawy, Hordienko et al, 2021, Seifert, 2017). Notably, components of the type III secretion apparatus were amongst down-regulated pathways in the xopQ- mutant (Appendix Table S5).…”

Section: Resultssupporting

confidence: 54%

A bacterial derived plant- mimicking cytokinin hormone regulates social behaviour in a rice pathogen

Deb

Kumar

et al. 2021

Preprint

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Many plant-associated bacteria produce plant- mimicking hormones which are involved in modulating host physiology. However, their function in modulating bacterial physiology has not been reported. Here we show that the XopQ protein, a type-III effector of the rice pathogen, Xanthomonas oryzae pv. oryzae (Xoo), is involved in cytokinin biosynthesis. Xoo produces and secretes an active form of cytokinin which enables the bacterium to maintain a planktonic lifestyle and promotes virulence. RNA-seq analysis indicates that the cytokinin produced by Xoo is required for the regulation of several genes which are involved in biofilm formation. We have also identified the Xoo isopentenyl transferase gene, which is involved in the cytokinin biosynthesis pathway and is required for maintaining planktonic behaviour and virulence. Furthermore, mutations in the predicted cytokinin receptor kinase (PcrK) and the downstream response regulator (PcrR) of Xoo phenocopy the cytokinin biosynthetic mutants, but are not complemented by supplementation with exogenous cytokinin. Cytokinin biosynthetic functions are encoded in a number of diverse bacterial genomes suggesting that cytokinin may be a widespread signalling molecule in the bacterial kingdom

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Section: Resultssupporting

confidence: 54%

A bacterial derived plant- mimicking cytokinin hormone regulates social behaviour in a rice pathogen

Deb

Kumar

et al. 2021

Preprint

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“…The demonstration that HU is a charge-neutralizing glue which allows the negatively-charged surface of a bacterium to bind to the negatively-charged surface of DNA suggested mechanisms for both (i) the embedment of bacteria within a matrix of DNA, and (ii) the generation of extracellular DNA to sustain the growth of the biofilm, through the occasional lysis of cells that tug at each other. Notably, the explosive lysis of bacterial cells that appear to tug at each other has been observed experimentally, and also shown to generate extracellular DNA [9,10]. Therefore, our identification of HU as a molecular glue answered questions both about how negatively-charged E. coli cells coexist with negatively charged DNA [8,11] in biofilms, and also about how extracellular DNA comes to exist in biofilms.…”

Section: Introductionmentioning

confidence: 79%

E. colicells advance into phase-separated (biofilm-simulating) extracellular polymeric substance containing DNA, HU, and lipopolysaccharide

Gupta,

Guptasarma

2024

Preprint

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We have earlier shown that HU, a nucleoid-associated protein, uses its DNA-binding surfaces to bind to bacterial outer-membrane lipopolysachharide (LPS), with this explaining how HU act as a potential glue for the adherence of bacteria to DNA, e.g., in biofilms. We have also earlier shown that HU and DNA together condense into a state of liquid-liquid phase separation (LLPS) both within, and outside, bacterial cells. Here, we report that HU and free LPS also condense into a state of phase separation, with coacervates of HU, DNA and free LPS being less liquid-like than condensates of HU and DNA alone.E. colicells bearing surface LPS and also shedding LPS, are shown to adhere to (as well as enter into) condensates of HU and DNA. HU thus appears to play a role in maintaining both an intracellular state of phase separation involving genomic nucleoids that are phase-separated from the cytoplasm, and an extracellular state of phase separation involving coacervates of extracellular DNA, HU and LPS, in the extracellular polymeric substances (EPS) of biofilms, in which LPS content is shown to modulate liquidity.ImportanceUnderstanding biofilm genesis and nature are crucial to understanding how to deal with the bacterial resistance to antibiotics that develops eventually in persistent biofilms. This study, together with two other recent landmark studies from our group, elucidates a novel aspect of the extracellular polymeric substance (EPS) of anEscherichia colibiofilm, by creating a simulacrum of the EPS and demonstrating that its formation involves liquid-liquid phase separation (LLPS) by its component HU, DNA, and lipopolysaccharide (LPS), with LPS determining the liquidity of the EPS simulacrum. The findings provide insight into the physical nature of biofilms but also suggests that the interplay of HU, DNA, and LPS facilitates the structural integrity and functional dynamics of biofilms. These findings are a stepping stone to the eventual development of strategies to disrupt biofilm.

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Tracing the origins of extracellular DNA in bacterial biofilms: story of death and predation to community benefit

2021

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Haemophilus spills its guts to make a biofilm

Cited by 3 publications

References 13 publications

A bacterial derived plant- mimicking cytokinin hormone regulates social behaviour in a rice pathogen

A bacterial derived plant- mimicking cytokinin hormone regulates social behaviour in a rice pathogen

E. colicells advance into phase-separated (biofilm-simulating) extracellular polymeric substance containing DNA, HU, and lipopolysaccharide

Tracing the origins of extracellular DNA in bacterial biofilms: story of death and predation to community benefit

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