The heat sensitive factor (HSF) of Yersinia ruckeriis produced by an alkyl sulphatase involved in sodium dodecyl sulphate (SDS) degradation but not in virulence

Abstract

Background: The heat sensitive factor (HSF) of the fish pathogen Yersinia ruckeri was previously identified as an unusual band on SDS-PAGE. According to this, Y. ruckeri strains were classified in HSF + and HSF − in terms of the presence/absence of the factor. Experiments carried out by injection challenge with HSF + strains caused high mortalities in rainbow trout. In contrast, HSF − strains did not cause mortality. In conclusion, HSF appeared to be a relevant virulence factor in Y. ruckeri. Results: We report here the identification and study of the gene coding for the enzyme involved in the production of HSF. Culture medium containing SDS and Coomassie brilliant blue dye was used to screen a mini-Tn5 Km2 mutant library of Y. ruckeri 150. Blue colonies lacking a surrounding creamy deposit, a phenotype described in former studies as HSF

The repeat structure of two paralogous genes, Yersinia ruckeri invasin (yrInv) and a “Y. ruckeri invasin-like molecule”, (yrIlm) sheds light on the evolution of adhesive capacities of a fish pathogen

“…Some Y. ruckeri strains are flagellated and consequently exhibit variable motility with peritrichously arranged flagella (Tobback et al, 2007). Y. ruckeri can be recovered from the internal organs of infected fish, and then cultured on bacteriological media such as Tryptone Soya Agar , Nutrient Agar (Navais et al, 2014), Brain Heart Infusion Agar (Arias et al, 2007), Columbia Blood Agar (Gibello et al, 2004) and McConkey Agar (Akhlaghi and Sharifi Yazdi, 2008;Gibello et al, 1999). After 24-48 hours of incubation, the bacterium forms smooth, circular, shiny colonies (Busch, 1978 catalase and negative for indole, hydrogen sulfide, oxidase, cytochrom, phosphatase, urease, phenylalanine deaminase (Ewing et al, 1978).…”

Yersinia ruckeri, the causative agent of enteric redmouth disease in fish

“…Heat sensitive factor (HSF) produced by the alkylsulphatase enzyme YraS has been proposed as a virulence factor [ 50 ], and a differential culture medium, using Coomassie Brilliant Blue has been developed to identify strains that carry this factor [ 51 ]. However, recent findings have contradicted these results and suggested that HSF might not be required for Y. ruckeri virulence [ 52 ]. Similarly, the cdsAB operon was initially identified through in vitro expression technology [ 49 ] and has been shown to be required for uptake of L-cysteine by the bacterium [ 53 ].…”

Genomic and Functional Characterization of Environmental Strains of SDS-Degrading Pseudomonas spp., Providing a Source of New Sulfatases

“…The third group includes enzymes with the metallo-β-lactamase-like domain in the N-terminus and SCP-2-like domain in C-terminus. Six sulfatases with different substrate specificities have been characterized to date: SdsA, YraS, and YjcS with activity toward sodium dodecyl sulfate (SDS) ( Davison et al, 1992 ; Liang et al, 2014 ; Navais et al, 2014 ), SdsAP and SdsA1 with activity toward primary sulfate esters including sodium dodecyl sulfate ( Hagelueken et al, 2006 ; Long et al, 2011 ; Schober et al, 2011 ) and Pisa1 with activity toward secondary alkyl sulfates ( Schober et al, 2011 ). Enzymes from this group differ in the mechanism of action and could cleave either S-O or C-O bond causing the retention or inversion of the product alcohol, which could be verified using chiral or labeled substrates.…”