LitR of Vibrio salmonicida Is a Salinity-Sensitive Quorum-Sensing Regulator of Phenotypes Involved in Host Interactions and Virulence

Bjelland, Ane Mohn; Sørum, Henning; Tegegne, Daget Ayana; Winther‐Larsen, Hanne C.; Willassen, Nils Peder; Hansen, Hilde

doi:10.1128/iai.06038-11

Cited by 40 publications

(103 citation statements)

References 68 publications

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“…In order to reveal potential targets for LitR regulation, we chose to grow the cells at low temperatures, when the differences in phenotypes between the wild type and ⌬litR mutant strains are most prominent. In addition, since the litR mutant is prone to aggregation in SWT medium (unpublished observation), as well as in other liquid media when grown at 4°C (39), it was necessary to grow planktonic cells at 8°C to monitor the cell density properly before harvest. Thus, for bacteria in suspension, the wild-type LFI1238 and the ⌬litR mutant were grown at 8°C in SWT medium with 200 rpm before being harvested at an OD 600 of 0.8.…”

Section: Methodsmentioning

confidence: 99%

“…Construction of V. salmonicida LFI1238 containing a litR in-frame deletion (⌬litR) and a complemented strain (⌬litR c ) have been described elsewhere (39). The ⌬litR double mutants used in the present study were made by chromosomal insertions mainly as described by others (43).…”

Section: Methodsmentioning

confidence: 99%

“…Finally, the inserts were excised from the agarose gel, purified, and ligated into the corresponding restriction sites of pNQ705 before the transformation of E. coli S17-1. The different pNQ705 suicidal constructs were transferred from the S17-1 donor cells to V. salmonicida recipient cells by conjugation as described elsewhere (39). It should be noted that chromosomal plasmid insertions are likely to create polar effects of downstream genes in an operon (43).…”

Section: Methodsmentioning

confidence: 99%

“…The litR open reading frame in the V. salmonicida wildtype isolates (Table 1) were amplified by a standard PCR using the LitR-G forward and LitR-H reverse primers, followed by sequencing using BigDye chemistry (39).…”

Section: Methodsmentioning

confidence: 99%

“…By light microscopy we found that LitR regulates negatively the formation of a loosely attached biofilm and speculated that a high content of polysaccharides prohibited quantification using traditional staining methods (39). In the present study, we have optimized the biofilm assay and show that V. salmonicida strains isolated at different geographic locations and with different plasmid profiles are poor biofilm producers at the chosen conditions.…”

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confidence: 99%

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LitR Is a Repressor of syp Genes and Has a Temperature-Sensitive Regulatory Effect on Biofilm Formation and Colony Morphology in Vibrio (Aliivibrio) salmonicida

Hansen

Bjelland

Ronessen

et al. 2014

Appl Environ Microbiol

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c Vibrio (Aliivibrio) salmonicida is the etiological agent of cold water vibriosis, a disease in farmed Atlantic salmon (Salmo salar) that is kept under control due to an effective vaccine. A seawater temperature below 12°C is normally required for disease development. Quorum sensing (QS) is a cell density-regulated communication system that bacteria use to coordinate activities involved in colonization and pathogenesis, and we have previously shown that inactivation of the QS master regulator LitR attenuates the V. salmonicida strain LFI1238 in a fish model. We show here that strain LFI1238 and a panel of naturally occurring V. salmonicida strains are poor biofilm producers. Inactivation of litR in the LFI1238 strain enhances medium-and temperaturedependent adhesion, rugose colony morphology, and biofilm formation. Chemical treatment and electron microscopy of the biofilm identified an extracellular matrix consisting mainly of a fibrous network, proteins, and polysaccharides. Further, by microarray analysis of planktonic and biofilm cells, we identified a number of genes regulated by LitR and, among these, were homologues of the Vibrio fischeri symbiosis polysaccharide (syp) genes. The syp genes were regulated by LitR in both planktonic and biofilm lifestyle analyses. Disruption of syp genes in the V. salmonicida ⌬litR mutant alleviated adhesion, rugose colony morphology, and biofilm formation. Hence, LitR is a repressor of syp transcription that is necessary for expression of the phenotypes examined. The regulatory effect of LitR on colony morphology and biofilm formation is temperature sensitive and weak or absent at temperatures above the bacterium's upper threshold for pathogenicity.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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LitR Is a Repressor of syp Genes and Has a Temperature-Sensitive Regulatory Effect on Biofilm Formation and Colony Morphology in Vibrio (Aliivibrio) salmonicida

Hansen

Bjelland

Ronessen

et al. 2014

Appl Environ Microbiol

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Fitness Factors in Vibrios: a Mini-review

Johnson

2013

Microb Ecol

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Vibrios are Gram-negative curved bacilli that occur naturally in marine, estuarine, and freshwater systems. Some species include human and animal pathogens, and some vibrios are necessary for natural systems, including the carbon cycle and osmoregulation. Countless in vivo and in vitro studies have examined the interactions between vibrios and their environment, including molecules, cells, whole animals, and abiotic substrates. Many studies have characterized virulence factors, attachment factors, regulatory factors, and antimicrobial resistance factors, and most of these factors impact the organism's fitness regardless of its external environment. This review aims to identify common attributes among factors that increase fitness in various environments, regardless of whether the environment is an oyster, a rabbit, a flask of immortalized mammalian cells, or a planktonic chitin particle. This review aims to summarize findings published thus far to encapsulate some of the basic similarities among the many vibrio fitness factors and how they frame our understanding of vibrio ecology. Factors representing these similarities include hemolysins, capsular polysaccharides, flagella, proteases, attachment factors, type III secretion systems, chitin binding proteins, iron acquisition systems, and colonization factors.

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Efficient surface modification of biomaterial to prevent biofilm formation and the attachment of microorganisms

Bazaka

Jacob

Crawford

et al. 2012

Appl Microbiol Biotechnol

206

134

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Biomaterials play a fundamental role in disease management and the improvement of health care. In recent years, there has been a significant growth in the diversity, function, and number of biomaterials used worldwide. Yet, attachment of pathogenic microorganisms onto biomaterial surfaces remains a significant challenge that substantially undermines their clinical applicability, limiting the advancement of these systems. The emergence and escalating pervasiveness of antibiotic-resistant bacterial strains makes the management of biomaterial-associated nosocomial infections increasingly difficult. The conventional post-operative treatment of implant-caused infections using systemic antibiotics is often marginally effective, further accelerating the extent of antimicrobial resistance. Methods by which the initial stages of bacterial attachment and biofilm formation can be restricted or prevented are therefore sought. The surface modification of biomaterials has the potential to alleviate pathogenic biofouling, therefore preventing the need for conventional antibiotics to be applied.

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LitR of Vibrio salmonicida Is a Salinity-Sensitive Quorum-Sensing Regulator of Phenotypes Involved in Host Interactions and Virulence

Abstract: ABSTRACTVibrio(Aliivibrio)salmonicidais the causal agent of cold-water vibriosis, a… Show more

Cited by 40 publications

References 68 publications

LitR Is a Repressor of syp Genes and Has a Temperature-Sensitive Regulatory Effect on Biofilm Formation and Colony Morphology in Vibrio (Aliivibrio) salmonicida

LitR Is a Repressor of syp Genes and Has a Temperature-Sensitive Regulatory Effect on Biofilm Formation and Colony Morphology in Vibrio (Aliivibrio) salmonicida

Fitness Factors in Vibrios: a Mini-review

Efficient surface modification of biomaterial to prevent biofilm formation and the attachment of microorganisms

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