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Papers by Xavier Rubires

L'interet actuel des systemes de detection rapide de micro-organismes dans l'industrie al... more L'interet actuel des systemes de detection rapide de micro-organismes dans l'industrie alimentaire est etroitement lie a son processus productif et a l'expedition du produit final. La microbiologie classique a base ses progres sur le developpement de milieux de culture specifiques et de preuves biochimiques permettant de distinguer differents micro-organismes, de facon quantitative et qualitative. Malgre l'universalite de son utilisation, ces techniques presentent l'inconvenient du temps : il est necessaire d'attendre de deux a trois jours pour obtenir des resultats fiables (par exemple, le comptage des colonies visibles) (11). Cet inconvenient provoque l'accumulation au stock de production ou magasin dans l'attente du resultat du controle de qualite du produit final, ce qui entraine une augmentation des couts de celui-ci. Le besoin de reduire le temps de detection des micro-organismes a entraine le developpement de nouvelles technologies permettant d...

Journal of Bacteriology, 1997

A cosmid-based genomic library of Serratia marcescens N28b was introduced into Escherichia coli D... more A cosmid-based genomic library of Serratia marcescens N28b was introduced into Escherichia coli DH5alpha, and clones were screened for serum resistance. One clone was found resistant to serum, to bacteriocin 28b, and to bacteriophages TuIa and TuIb. This clone also showed O antigen in its lipopolysaccharide. Subcloning and sequencing experiments showed that a 2,124-bp DNA fragment containing the rmlD and wbbL genes was responsible for the observed phenotypes. On the basis of amino acid similarity, we suggest that the 288-residue RmlD protein is a dTDP-L-rhamnose synthase. Plasmid pJT102, containing only the wbbL gene, was able to induce O16-antigen production and serum resistance in E. coli DH5alpha. These results suggest that the 282-residue WbbL protein is a rhamnosyltransferase able to complement the rJb-50 mutation in E. coli K-12 derivatives, despite the low level of amino acid identity between WbbL and the E. coli rhamnosyltransferase (24.80%). S. marcescens N28b rmlD and wbbL...

Molecular Wine Microbiology, 2011

CHAPTER 14 Applied Wine Microbiology Braulio Esteve-Zarzoso 1, Mireia Martínez 2, Xavier Rubires ... more CHAPTER 14 Applied Wine Microbiology Braulio Esteve-Zarzoso 1, Mireia Martínez 2, Xavier Rubires 3, María Yuste-Rojas 2, Mireia Torres 2 1 Dpt Bioquimica i Biotecnologia, Universitat Rovira i Virgili, Tarragona, Spain, 2 Miguel Torres, Barcelona, Spain and 3 Pago Jean ...

Annals of the New York Academy of Sciences, 1996

International Journal of Food Microbiology, 1995

Aeromonas spp. are Gram-negative rods of the family Vibrionaceae. They are normal water inhabitan... more Aeromonas spp. are Gram-negative rods of the family Vibrionaceae. They are normal water inhabitants and are part of the regular flora of poiquilotherm and homeotherm animals. They can be isolated from many foodstuffs (green vegetables, raw milk, ice cream, meat and seafood). Mesophilic Aeromonas spp. have been classified following the AeroKey II system (Altwegg et al., 1990; Carnahan et al., 1991). The major human diseases caused by Aeromonas spp. can be classified in two major groups: septicemia (mainly by strains of A. veronii subsp. sobria and A. hydrophila), and gastroenteritis (any mesophilic Aeromonas spp. but principally A. hydrophila and A. veronii). Most epidemiological studies have shown Aeromonas spp. in stools to be more often associated with diarrhea than with the carrier state; an association with the consumption of untreated water was also conspicuous. Acute self-limited diarrhea is more frequent in young children, in older patients chronic enterocolitis may also be observed. Fever, vomiting, and fecal leukocytes or erythrocytes (colitis) may be present (Janda, 1991). The main putative virulence factors are: exotoxins, endotoxin (LPS), presence of S-layers, fimbriae or adhesins and the capacity to form capsules.

Journal of Bacteriology, 1997

Growth of Aeromonas hydrophila serotype O:34 strains at 37؇C at low and high osmolarity resulted ... more Growth of Aeromonas hydrophila serotype O:34 strains at 37؇C at low and high osmolarity resulted in changes in the lipopolysaccharide (LPS) and virulence of the strains tested. We previously described the effect of growth temperature on LPS and virulence of these strains (S. Merino et al., Infect. Immun. 60:4343-4349, 1992). The effect of osmolarity can be observed when the cells grow at 37؇C but not when they grow at 20؇C. Purified LPS from cells cultivated at 37؇C and high osmolarity was smooth, while the LPS extracted from the cells cultivated at low osmolarity was rough. Furthermore, the strains were more virulent for fish and mice when they were grown at high osmolarity than when they were grown at low osmolarity and also showed increased extracellular activities when they were grown at high osmolarity. Finally, cells grown at high osmolarity showed better adhesion to HEp-2 cells than the same cells grown at low osmolarity, and furthermore the cells grown at high osmolarity were resistant to the bactericidal activity of nonimmune serum, while the same cells grown at low osmolarity were sensitive.

The interaction between C1q, a subcomponent of the complement classical pathway component C1, and... more The interaction between C1q, a subcomponent of the complement classical pathway component C1, and OmpK36, a porin protein from Klebsiella pneumoniae, was studied in a solid-phase direct-binding assay, inhibition assays with the purified globular and collagen-like regions of C1q, and cross-linking experiments. We have shown that the binding of C1q to the OmpK36 porin of the serum-sensitive strain K. pneumoniae KT707 occurs in an in vivo situation and that this binding leads to activation of the complement classical pathway and the subsequent deposition of complement components C3b and C5b-9 on the OmpK36 porin.

Fems Microbiol Lett, 2006

Infection and Immunity, Aug 1, 1998

The mechanism of killing of Aeromonas hydrophila serum-sensitive strains in nonimmune serum by th... more The mechanism of killing of Aeromonas hydrophila serum-sensitive strains in nonimmune serum by the complement classical pathway has been studied. The bacterial cell surface component that binds C1q more efficiently was identified as a major outer membrane protein of 39 kDa, presumably the porin II described by D. Jeanteur, N. Gletsu, F. Pattus, and J. T. Buckley (Mol. Microbiol. 6:3355-3363, 1992), of these microorganisms. We have demonstrated that the purified form of porin II binds C1q and activates the classical pathway in an antibody-independent manner, with the subsequent consumption of C4 and reduction of the serum total hemolytic activity. Activation of the classical pathway has been observed in human nonimmune serum and agammaglobulinemic serum (both depleted of factor D). Binding of C1q to other components of the bacterial outer membrane, in particular to rough lipopolysaccharide, could not be demonstrated. Activation of the classical pathway by this lipopolysaccharide was also much less efficient than activation by the outer membrane protein. The strains possessing O-antigen lipopolysaccharide bind less C1q than the serumsensitive strains, because the outer membrane protein is less accessible, and are resistant to complementmediated killing. Finally, a similar or identical outer membrane protein (presumably porin II) that binds C1q was shown to be present in strains from the most common mesophilic Aeromonas O serogroups.

Research in Microbiology, Feb 28, 1997

A cosmid-based genomic library of Klebsiella pneumoniae 52145 (01X2) was introduced into Escheric... more A cosmid-based genomic library of Klebsiella pneumoniae 52145 (01X2) was introduced into Escherichia co/i, and clones were screened for the bacteriocin 28b resistance phenotype. One clone was found which conferred partial resistance to bacteriocin 28b. By using Tn5tacl insertions, it was shown that this phenotype was due to the expression, in I?!. co/i, of an outer-membrane protein (OMP) with an apparent molecular mass of 17 kDa (OmpK17). The DNA region defined by insertion mutagenesis was sequenced and found to contain an ORF of 510 bp. The deduced amino acid sequence has 170 residues with a theoretical molecular mass of 18.4 kDa. The protein contains an N-terminal signal sequence of 24 amino acid residues. When compared with other enterobacterial OMPs, OmpK17 most closely resembles members of a family of small OMPs of Enter& bacferiaceae the known functions of which appear to be related to virulence. Immunoblotting experiments showed that OmpK17 is also present in various K. pneumoniae strains belonging to diierent 0 and K serotypes.

Infection and Immunity, Dec 1, 1996

The complement activation by and resistance to complement-mediated killing of Aeromonas sp. strai... more The complement activation by and resistance to complement-mediated killing of Aeromonas sp. strains from serogroup O:11 were investigated by using different wild-type strains (with an S-layer characteristic of this serogroup) and their isogenic mutants characterized for their surface components (S-layer and lipopolysaccharide [LPS]). All of the Aeromonas sp. serogroup O:11 wild-type strains are unable to activate complement, which suggested that the S-layer completely covered the LPS molecules. We found that the classical complement pathway is involved in serum killing of susceptible Aeromonas sp. mutant strains of serogroup O11, while the alternative complement pathway seems not to be involved, and that the complement activation seems to be independent of antibody. The smooth mutant strains devoid of the S-layer (S-layer isogenic mutants) or isogenic LPS mutant strains with a complete or rather complete LPS core (also without the S-layer) are able to activate complement but are resistant to complement-mediated killing. The reasons for this resistance are that C3b is rapidly degraded, and therefore the lytic membrane attack complex (C5b-9) is not formed. Isogenic LPS rough mutants with an incomplete LPS core are serum sensitive because they bind more C3b than the resistant strains, the C3b is not completely degraded, and therefore the lytic complex (C5b-9) is formed.

Fems Microbiol Lett, 1995

Mesophilic Aeromonas hydrophilu from serotypes 0:ll and 0:34 grown in a glucose-rich medium produ... more Mesophilic Aeromonas hydrophilu from serotypes 0:ll and 0:34 grown in a glucose-rich medium produce a capsule that can be seen under light and electron microscopy. The purified capsular polysacoharide has a composition qualitatively similar for strains 0:ll and 0:34, but quantitatively different. The capsular polysacoharides were immunogenic in rabbits, and did not cross-react with specitk antibodies against either purified lipopolysacoharide from strains 0:34 or 0:ll or against the S-layer characteristic of strains from serotype 0:ll.

International Journal of Food Microbiology, 1995

Infection and Immunity, Feb 1, 1999

The bacterial capsule is an important virulence determinant in animal and plant disease. Bacteria... more The bacterial capsule is an important virulence determinant in animal and plant disease. Bacterial capsule and slime can be inhibited by bismuth compounds, especially when complexed with lipophilic thiol chelators. Bismuth dimercaprol (BisBAL) at 1 ppm of Bi 3؉ repressed Klebsiella pneumoniae capsule expression in defined medium by nearly 90%, which exposed subsurface structures. The phagocytic index for BisBAL-treated bacteria increased from <10 to 360 bacteria per 100 neutrophils in the presence of complement and anticapsular or anti-O antigen antiserum. BisBAL treatment also enhanced the reactivity of monoclonal antibodies (MAbs) specific for the O1-antigen lipopolysaccharide (LPS) or the LPS core in a dose-dependent manner as indicated by the results of enzyme-linked immunosorbent assays. When anti-O1 MAb was used, the reactivity increased significantly for fully encapsulated O1:K1 or O1:K2 cells but not for O1:K ؊ cells. Deposition of C3b also increased significantly for BisBAL-treated O1:K1 or O1:K2 cells but not for O1:K ؊ cells. Survival of a serumsensitive strain was <0.1% when nonimmune human serum absorbed with O1:K1 cells was used and 107% when BisBAL-treated cells were used for absorption. Outer membrane proteins were also more accessible on the surface of K. pneumoniae after BisBAL treatment. Thus, at subinhibitory levels, BisBAL inhibited capsule expression, which promoted phagocytosis, enhanced the reactivity of specific antibodies for LPS O antigen, LPS core epitopes, or outer-membrane proteins, and enhanced complement interaction with encapsulated K. pneumoniae. By unmasking bacterial surface structures and enhancing the immune system reactivity to bacteria, bismuth thiols may prove useful as adjuncts for vaccination.

The Serratia marcescens N28b wbbL gene has been shown to complement the rfb-50 mutation of Escher... more The Serratia marcescens N28b wbbL gene has been shown to complement the rfb-50 mutation of Escherichia coli K-12 derivatives, and a wbbL mutant has been shown to be impaired in O4-antigen biosynthesis (X. Rubires, F. Saigi ´, N. Pique ´, N. Climent, S. Merino, S. Alberti ´, J. M. Tomas, and M. Regue ´, J. Bacteriol. 179:7581-7586, 1997). We analyzed

Infection and immunity, 1999

Research in microbiology, 1997

A cosmid-based genomic library of Klebsiella pneumoniae 52145 (O1:K2) was introduced into Escheri... more A cosmid-based genomic library of Klebsiella pneumoniae 52145 (O1:K2) was introduced into Escherichia coli, and clones were screened for the bacteriocin 28b resistance phenotype. One clone was found which conferred partial resistance to bacteriocin 28b. By using Tn5tac1 insertions, it was shown that this phenotype was due to the expression, in E. coli, of an outer-membrane protein (OMP) with an apparent molecular mass of 17 kDa (OmpK17). The DNA region defined by insertion mutagenesis was sequenced and found to contain an ORF of 510 bp. The deduced amino acid sequence has 170 residues with a theoretical molecular mass of 18.4 kDa. The protein contains an N-terminal signal sequence of 24 amino acid residues. When compared with other enterobacterial OMPs, OmpK17 most closely resembles members of a family of small OMPs of Enterobacteriaceae the known functions of which appear to be related to virulence. Immunoblotting experiments showed that OmpK17 is also present in various K. pneumon...

Journal of Bacteriology, 1997

Molecular Wine Microbiology, 2011

Annals of the New York Academy of Sciences, 1996

International Journal of Food Microbiology, 1995

Journal of Bacteriology, 1997

Fems Microbiol Lett, 2006

Infection and Immunity, Aug 1, 1998

Research in Microbiology, Feb 28, 1997

Infection and Immunity, Dec 1, 1996

Fems Microbiol Lett, 1995

International Journal of Food Microbiology, 1995

Infection and Immunity, Feb 1, 1999

Infection and immunity, 1999

Research in microbiology, 1997