Relevance of incubation temperature for Vibrio salmonicida vaccine production

Colquhoun, D.J.; Alvheim, K.; Dommarsnes, Kari; Syvertsen, Christian; Sørum, Henning

doi:10.1046/j.1365-2672.2002.01643.x

Cited by 26 publications

(16 citation statements)

References 16 publications

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“…salmonicida causes disease in the Atlantic salmon when the seawater temperature is below 10 to 12°C (35). In the laboratory, V. salmonicida grows at temperatures between 1 and 22°C, with a growth optimum at 12°C in liquid cultures and at 15°C on agar plates (33,35).…”

Section: Discussionmentioning

confidence: 99%

“…Vibrio (Aliivibrio) salmonicida causes cold-water vibriosis in farmed salmonid fish, and the disease occurs mainly in late autumn, winter, and early spring when the water temperature is below 12°C (31)(32)(33)(34)(35). The environmental lifestyle and transmission route of V. salmonicida is unclear but may be through the seawater either as bacterioplankton or on the surfaces of particles (32).…”

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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: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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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“…For challenge experiments, fish were exposed to V. salmonicida cells that were recently passaged through fish to verify and prepare virulence (16,61). The challenge doses were established based on a prechallenge experiment as well as on previous studies (7,12,47,48). Mortality was monitored daily for a period of 3 weeks.…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2012

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ABSTRACTVibrio(Aliivibrio)salmonicidais the causal agent of cold-water vibriosis, a fatal bacterial septicemia primarily of farmed salmonid fish. The molecular mechanisms of invasion, colonization, and growth ofV. salmonicidain the host are still largely unknown, and few virulence factors have been identified. Quorum sensing (QS) is a cell-to-cell communication system known to regulate virulence and other activities in several bacterial species. The genome ofV. salmonicidaLFI1238 encodes products presumably involved in several QS systems. In this study, the gene encoding LitR, a homolog of the master regulator of QS inV. fischeri, was deleted. Compared to the parental strain, thelitRmutant showed increased motility, adhesion, cell-to-cell aggregation, and biofilm formation. Furthermore, thelitRmutant produced less cryptic bioluminescence, whereas production of acylhomoserine lactones was unaffected. Our results also indicate a salinity-sensitive regulation of LitR. Finally, reduced mortality was observed in Atlantic salmon infected with thelitRmutant, implying that the fish were more susceptible to infection with the wild type than with the mutant strain. We hypothesize that LitR inhibits biofilm formation and favors planktonic growth, with the latter being more adapted for pathogenesis in the fish host.

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“…The bacterium with one of the lowest growth optimum temperatures found in the genus Vibrio is the fish pathogen Vibrio salmonicida. It has an optimal growth temperature of % 15°C and requires NaCl for growth [3]. It can therefore be classified as a psychrophilic and mildly halophilic bacterium.A living cell can be considered as a chemical factory which produces many substances.…”

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Comparative studies of endonuclease I from cold‐adapted Vibrio salmonicida and mesophilic Vibrio cholerae

et al. 2006

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The marine and estuarine environment harbors a vast diversity of bacteria. Some of the most extensively studied marine or estuarine bacteria belong to the genus Vibrio, with Vibrio cholerae being the most notorious species as it is the cause of cholera in humans. V. cholerae is found in tropical and temperate areas, and can be classified as a mesophilic bacterium with growth optimum around 37°C. It prefers estuarine waters, is halotolerant, and does not require NaCl for growth [1,2]. The bacterium with one of the lowest growth optimum temperatures found in the genus Vibrio is the fish pathogen Vibrio salmonicida. It has an optimal growth temperature of % 15°C and requires NaCl for growth [3]. It can therefore be classified as a psychrophilic and mildly halophilic bacterium.A living cell can be considered as a chemical factory which produces many substances. The speed of production is limited by reaction rates. The reaction rates are in turn limited by, among other things, environmental factors such as pH, salinity, pressure and temperature. Temperature is a very important factor for growth and proliferation of the cells. At high temperatures, at which thermophiles thrive, chemical reaction rates are very high, and the main challenge for cells is to adapt their enzymes, membranes and molecules to cope with the heat. At low temperatures, the chemical reaction rates are lower, and hence, in order to be competitive and grow fast at low temperatures, evolutionary pressure favors enzymes that are more efficient than their high-temperature counterparts. This higher efficiency at low temperatures is believed to be caused Endonuclease I is a periplasmic or extracellular enzyme present in many different Proteobacteria. The endA gene encoding endonuclease I from the psychrophilic and mildly halophilic bacterium Vibrio salmonicida and from the mesophilic brackish water bacterium Vibrio cholerae have been cloned, over-expressed in Escherichia coli, and purified. A comparison of the enzymatic properties shows large differences in NaCl requirements, optimum pH, temperature stability and catalytic efficiency of the two proteins. The V. salmonicida EndA shows typical cold-adapted features such as lower unfolding temperature, lower temperature optimum for activity, and higher specific activity than V. cholerae EndA. The thermodynamic activation parameters confirm the psychrophilic nature of V. salmonicida EndA with a much lower activation enthalpy. The optimal conditions for enzymatic activity coincide well with the corresponding optimal requirements for growth of the organisms, and the enzymes function predominantly as DNases at physiological concentrations of NaCl. The periplasmic or extracellular localization of the enzymes, which renders them constantly exposed to the outer environment of the cell, may explain this fine-tuning of biochemical properties.Abbreviations DSC, differential scanning calorimetry; VcEndA, recombinant Vibrio cholerae endonuclease I; VsEndA, recombinant Vibrio salmonicida endonuclease I.

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Relevance of incubation temperature for Vibrio salmonicida vaccine production

Cited by 26 publications

References 16 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

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

Comparative studies of endonuclease I from cold‐adapted Vibrio salmonicida and mesophilic Vibrio cholerae

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