Biofilm formation at the air-liquid interface by the Pseudomonas fluorescens SBW25 wrinkly spreader requires an acetylated form of cellulose

The wrinkly spreader (WS) isolate of Pseudomonas fluorescens SBW25 forms a substantial biofilm at the air–liquid interface. The biofilm is composed of an extracellular partially acetylated cellulose-fibre matrix, and previous mutagenesis of WS with mini-Tn5 had identified both the regulatory and cellulose-biosynthetic operons. One uncharacterized WS mutant, WS-5, still expressed cellulose but produced very weak biofilms. In this work, the mini-Tn5 insertion site in WS-5 has been identified as being immediately upstream of the tol-pal operon. Like Tol-Pal mutants of other Gram-negative bacteria, WS-5 showed a ‘leaky-membrane’ phenotype, including the serendipitous ability to utilize sucrose, increased uptake of the hydrophilic dye propidium iodide, and the loss of lipopolysaccharide (LPS) expression. WS-5 cells were altered in relative hydrophobicity, and showed poorer recruitment and maintenance in the biofilm than WS. The WS-5 biofilm was also less sensitive to chemical interference during development. However, growth rate, cellulose expression and attachment were not significantly different between WS and WS-5. Finally, WS-5 biofilms could be partially complemented with WS-4, a biofilm- and attachment-deficient mutant that expressed LPS, resulting in a mixed biofilm with significantly increased strength. These findings show that a major component of the WS air–liquid biofilm strength results from the interactions between LPS and the cellulose matrix of the biofilm – and that in the WS biofilm, cellulose fibres, attachment factor and LPS are required for biofilm development, strength and integrity.

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Disruption of Escherichia coli Amyloid-Integrated Biofilm Formation at the Air–Liquid Interface by a Polysorbate Surfactant

Langmuir ◽

10.1021/la304710k ◽

2013 ◽

Vol 29 (3) ◽

pp. 920-926 ◽

Cited By ~ 22

Author(s):

Cynthia Wu ◽

Ji Youn Lim ◽

Gerald G. Fuller ◽

Lynette Cegelski

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Liquid Interface ◽

Air Liquid Interface

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Extending an Eco-Evolutionary Understanding of Biofilm-Formation at the Air-Liquid Interface to Community Biofilms

Bacterial Biofilms ◽

10.5772/intechopen.90955 ◽

2020 ◽

Author(s):

Robyn Jerdan ◽

Olga Iungin ◽

Olena V. Moshynets ◽

Geert Potters ◽

Andrew J. Spiers

Keyword(s):

Biofilm Formation ◽

Liquid Interface ◽

Air Liquid Interface

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Evolutionary flexibility in routes to mat formation by Pseudomonas

10.1101/2021.08.03.454897 ◽

2021 ◽

Author(s):

Anuradha Mukherjee ◽

Jenna Gallie

Keyword(s):

Pseudomonas Fluorescens ◽

Liquid Interface ◽

Secondary Messenger ◽

Diguanylate Cyclases ◽

Close Relatives ◽

High Level ◽

Air Liquid Interface ◽

Gmp Production

Many bacteria form mats at the air-liquid interface of static microcosms. These structures typically involve the secretion of exopolysaccharide(s), the production of which is often controlled by the secondary messenger c-di-GMP. Mechanisms of mat formation have been particularly well characterized in Pseudomonas fluorescens SBW25; mutations that lead to an increase in c-di-GMP production by diguanylate cyclases (WspR, AwsR, or MwsR) result in the secretion of cellulose, and mat formation. Here, we characterize and compare mat formation in two close relatives of SBW25: Pseudomonas simiae PICF7 and Pseudomonas fluorescens A506. We find that PICF7 – the strain more closely related to SBW25 – can form mats through mutations affecting the activity of the same three diguanylate cyclases as SBW25. However, instead of cellulose, these mutations activate the production of the Pel exopolysaccharide. We also provide evidence for at least two further – as yet uncharacterized – routes to PICF7 mat formation. P. fluorescens A506, while retaining the same mutational routes to mat formation as SBW25 and PICF7, forms mats by a semi-heritable mechanism that likely culminates in Pga and/or Psl production. Overall, our results demonstrate a high level of evolutionary flexibility in the molecular and structural routes to mat formation, even among close relatives.

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Protozoan predation drives adaptive divergence in Pseudomonas fluorescens SBW25; ecology meets experimental evolution.

10.1101/2021.07.12.452127 ◽

2021 ◽

Author(s):

Farhad S. Golzar ◽

Gayle C. Ferguson ◽

Heather L Hendrickson

Keyword(s):

Pseudomonas Fluorescens ◽

Adaptive Divergence ◽

Predator Prey ◽

Solid Media ◽

Short Period ◽

Bacterial Mutants ◽

Evolution Experiment ◽

Grazing Resistance ◽

Pseudomonas Fluorescens Sbw25 ◽

Air Liquid Interface

Protozoan predators can affect the structure of bacterial communities, but investigations of how predation might influence bacterial evolution and antagonistic behaviours are scarce. Here, we performed a 20-day predator-prey evolution experiment on solid media to investigate the effect of continuous protozoan predation on bacterial traits using Pseudomonas fluorescens SBW25 as prey and Naegleria gruberi as an amoeboid predator. We observed the divergence of colony morphotypes coincident with an increase in bacterial grazing resistance and relative prey fitness in selected bacterial isolates. When subjected to these resistant prey, N. gruberi show reduced activity (increased encystment) and limited replication. An investigation of the mutations responsible for predation resistance reveals mutations in wspF and amrZ genes, affecting biofilm formation and motility. The bacterial mutants in the wspF gene successfully colonise the air-liquid interface and produce robust cellulose biofilms that prevent predation. The mutation in the amrZ mutant withstands predation but this variant produces low levels of cellulose and limited swarming motility. Our findings suggest that protozoan predation can profoundly influence the course of genetic and phenotypic evolution in a short period.

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Examining c-di-GMP and possible quorum sensing regulation in Pseudomonas fluorescens SBW25: links between intra- and inter-cellular regulation benefits community cooperative activities such as biofilm formation

The Ukrainian Biochemical Journal ◽

10.15407/ubj90.03.017 ◽

2018 ◽

Vol 90 (3) ◽

pp. 17-31 ◽

Cited By ~ 1

Author(s):

O. V. Moshynets ◽

◽

D. Foster ◽

S. A. Karakhim ◽

K. McLaughlin ◽

...

Keyword(s):

Quorum Sensing ◽

Pseudomonas Fluorescens ◽

Biofilm Formation ◽

Cellular Regulation ◽

Pseudomonas Fluorescens Sbw25

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Biofilm Formation by and Multicellular Behavior of Escherichia coli O55:H7, an Atypical Enteropathogenic Strain

Applied and Environmental Microbiology ◽

10.1128/aem.01395-09 ◽

2010 ◽

Vol 76 (5) ◽

pp. 1545-1554 ◽

Cited By ~ 43

Author(s):

Michal Weiss-Muszkat ◽

Dana Shakh ◽

Yizhou Zhou ◽

Riky Pinto ◽

Eddy Belausov ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Genetic Relatedness ◽

Liquid Interface ◽

E Coli ◽

Wild Type Phenotype ◽

Enteropathogenic Strain ◽

Biofilm Development ◽

Air Liquid Interface ◽

High Degree

ABSTRACT Enteropathogenic Escherichia coli (EPEC) is an important causal agent of diarrheal illness throughout the world. Nevertheless, researchers have only recently begun to explore its capacity to form biofilms. Strain O55:H7 (DMS9) is a clinical isolate belonging to the atypical EPEC (aEPEC) group, which displays a high degree of genetic relatedness to enterohemorrhagic E. coli. Strain DMS9 formed a robust biofilm on an abiotic surface at 26Ã¯Â¿Â½C, but not at 37Ã¯Â¿Â½C. It also formed a dense pellicle at the air-liquid interface and developed a red, rough, and dry (RDAR) morphotype on Congo red agar. Unlike a previously described E. coli O157:H7 strain, the aEPEC strain seems to express cellulose. Transposon mutagenesis was used to identify biofilm-deficient mutants. One of the mutants was inactivated in the csgFG genes, required for assembly and secretion of curli fimbriae, while a second mutant had a mutation in crl, a thermosensitive global regulator that modulates σS activity and downstream expression of curli and cellulose. The two mutants were deficient in their biofilm formation capabilities and did not form a pellicle at the air-liquid interface. Unlike in Salmonella, the csgFG mutant in aEPEC completely lost the RDAR phenotype, while the crl mutant displayed a unique RDAR “pizza”-like morphotype. Genetic complementation of the two mutants resulted in restoration of the wild-type phenotype. This report is the first to describe and analyze a multicellular behavior in aEPEC and support a major role for curli and the crl regulator in biofilm development at low temperatures corresponding to the nonmammalian host environment.

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Biofilm formation by South African non-O157 Shiga toxigenic Escherichia coli on stainless steel coupons

Canadian Journal of Microbiology ◽

10.1139/cjm-2019-0554 ◽

2020 ◽

Vol 66 (4) ◽

pp. 328-336 ◽

Cited By ~ 3

Author(s):

Emmanuel W. Bumunang ◽

Collins N. Ateba ◽

Kim Stanford ◽

Tim A. McAllister ◽

Yan D. Niu

Keyword(s):

Escherichia Coli ◽

Stainless Steel ◽

South African ◽

Food Processing ◽

Biofilm Formation ◽

Viable Cell ◽

Liquid Interface ◽

Cell Counts ◽

Potential Source ◽

Air Liquid Interface

This study examined the biofilm-forming ability of six non-O157 Shiga-toxin-producing Escherichia coli (STEC) strains: O116:H21, wzx-Onovel5:H19, O129:H21, O129:H23, O26:H11, and O154:H10 on stainless steel coupons after 24, 48, and 72 h of incubation at 22 °C and after 168 h at 10 °C. The results of crystal violet staining revealed that strains O129:H23 and O154:H10 were able to form biofilms on both the submerged surface and the air–liquid interface of coupons, whereas strains O116:H21, wzx-Onovel5:H19, O129:H21, and O26:H11 formed biofilm only at the air–liquid interface. Viable cell counts and scanning electron microscopy showed that biofilm formation increased (p < 0.05) over time. The biofilm-forming ability of non-O157 STEC was strongest (p < 0.05) at 22 °C after 48 h of incubation. The strongest biofilm former regardless of temperature was O129:H23. Generally, at 10 °C, weak to no biofilm was observed for isolates O154:H10, O116:H21, wzx-Onovel5:H19, O26:H11, and O129:H21 after 168 h. This study found that temperature affected the biofilm-forming ability of non-O157 STEC strains. Overall, our data indicate a high potential for biofilm formation by the isolates at 22 °C, suggesting that non-O157 STEC strains could colonize stainless steel within food-processing facilities. This could serve as a potential source of adulteration and promote the dissemination of these potential pathogens in food.

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