Search results for " Outer"
showing 10 items of 129 documents
The Fish Pathogen Vibrio vulnificus Biotype 2: Epidemiology, Phylogeny, and Virulence Factors Involved in Warm-Water Vibriosis
2015
ABSTRACT Vibrio vulnificus biotype 2 is the etiological agent of warm-water vibriosis, a disease that affects eels and other teleosts, especially in fish farms. Biotype 2 is polyphyletic and probably emerged from aquatic bacteria by acquisition of a transferable virulence plasmid that encodes resistance to innate immunity of eels and other teleosts. Interestingly, biotype 2 comprises a zoonotic clonal complex designated as serovar E that has extended worldwide. One of the most interesting virulence factors produced by serovar E is RtxA1 3 , a multifunctional protein that acts as a lethal factor for fish, an invasion factor for mice, and a survival factor outside the host. Two practically id…
Israeli Spotted FeverRickettsiain SicilianRhipicephalus sanguineusTicks
2003
To the Editor: Mediterranean spotted fever (MSF) is endemic in Italy, where it is a reportable disease. From 1992 to 1998, the Italian Ministry of Health was notified of approximately 8,500 cases of human rickettsioses presumed to be MSF. MSF occurs more commonly in some central (Lazio) and southern (Sardinia, Sicily, and Calabria) regions (1,2); in 1998, an average of 8.8 cases occurred for every 100,000 persons in Sicily, compared with the national average of 1.6 cases per 100,000 persons. Rickettsia conorii has been thought to be the only pathogenic Rickettsia of the spotted fever group in Sicily (3,4) or the western Mediterranean area. Recently, three different spotted fever group ricke…
Characteristics of Escherichia coli strains belonging to enteropathogenic E. coli serogroups isolated in Italy from children with diarrhea.
1996
Fifty-five Escherichia coli strains belonging to enteropathogenic E. coli (EPEC) serogroups were examined for phenotypic and genetic factors associated with virulence. The strains were isolated in Italy from children with diarrhea and identified as EPEC by clinical laboratories using commercially available antisera. O:H serotyping showed that 35 strains (27 of O26, O111, and O128 serogroups) belonged to 11 serotypes considered to be classical EPEC O:H serotypes. The other 20 isolates were classified as 15 nonclassical EPEC O:H serotypes. All the potential EPEC virulence factors associated with bacterial adhesion (localized adherence, fluorescentactin staining test positivity, presence of th…
Expression of Staphylococcus saprophyticus surface properties is modulated by composition of the atmosphere.
1995
Expression of two major surface proteins of Staphylococcus saprophyticus, the haemagglutinin and the Staphylococcus saprophyticus surface-associated protein (Ssp), requires carefully defined culture conditions. The Ssp is produced when bacteria are grown on agar, whereas expression of the haemagglutinin requires growth in broth. We sought to identify the environmental signals that are responsible for this modulation. Varying the pH, the osmolarity of the growth medium or the temperature did not influence expression of the proteins. In contrast, growth in an anaerobic atmosphere increased haemagglutination titres and fibronectin binding (both mediated by the haemagglutinin) but suppressed pr…
Permeabilization of the Outer Mitochondrial Membrane by Bcl-2 Proteins
2010
The proteins of the Bcl-2 family regulate the release of the apoptotic factors from mitochondria during apoptosis, a key event in physiological cell death. Although their molecular mechanisms remain unclear, the Bcl-2 proteins have been proposed to directly control the permeability of the outer mitochondrial membrane by pore formation. Indeed, they share structural features with the pore forming domains of some bacterial toxins and they can give rise to proteolipidic pores in model membranes. The complex level of regulation needed to decide the fate of the cell is achieved by an intricate interaction network between different members of the family. Current models consider multiple parallel …
Crystal structure of the N-terminal domain of the major virulence factor BB0323 from the Lyme disease agent Borrelia burgdorferi.
2019
Lyme disease is an infection caused by the spirochete Borrelia burgdorferi after it is transmitted to a mammalian organism during a tick blood meal. B. burgdorferi encodes at least 140 lipoproteins located on the outer or inner membrane, thus facing the surroundings or the periplasmic space, respectively. However, most of the predicted lipoproteins are of unknown function, and only a few proteins are known to be essential for the persistence and virulence of the pathogen. One such protein is the periplasmic BB0323, which is indispensable for B. burgdorferi to cause Lyme disease and the function of which is associated with cell fission and outer membrane integrity. After expression and trans…
Peptides Derived from Apoptotic Bax and Bid Reproduce the Poration Activity of the Parent Full-Length Proteins
2005
Bax and Bid are proapoptotic proteins of the Bcl-2 family that regulate the release of apoptogenic factors from mitochondria. Although they localize constitutively in the cytoplasm, their apoptotic function is exerted at the mitochondrial outer membrane, and is related to their ability to form transbilayer pores. Here we report the poration activity of fragments from these two proteins, containing the first alpha-helix of a colicinlike hydrophobic hairpin (alpha-helix 5 of Bax and alpha-helix 6 of Bid). Both peptides readily bind to synthetic lipid vesicles, where they adopt predominantly alpha-helical structures and induce the release of entrapped calcein. In planar lipid membranes they fo…
Crystal structure of the infectious phenotype-associated outer surface protein BBA66 from the Lyme disease agent Borrelia burgdorferi
2014
Borrelia burgdorferi, the causative agent of Lyme disease is transmitted to the mammalian host organisms by infected Ixodes ticks. Transfer of the spirochaetal bacteria from Ixodes ticks to the warm-blooded mammalian organism provides a challenge for the bacteria to adapt and survive in the different environmental conditions. B. burgdorferi has managed to differentially express genes in response to the encountered changes such as temperature and pH variance or metabolic rate to survive in both environments. In recent years, much interest has been turned on genes that are upregulated during the borrelial transfer to mammalian organisms as this could reveal the proteins important in the patho…
Structural characterization of the Borrelia burgdorferi outer surface protein BBA73 implicates dimerization as a functional mechanism.
2013
Borrelia burgdorferi, which is the causative agent of Lyme disease, is transmitted from infected Ixodes ticks to a mammalian host following a tick bite. Upon changing the host organism from an Ixodes tick to a warm-blooded mammal, the spirochete must adapt to very different conditions, which is achieved by altering the expression of several genes in response to a changing environment. Recently, considerable attention has been devoted to several outer surface proteins, including BBA73, that undergo dramatic upregulation during the transmission of B. burgdorferi from infected Ixodes ticks to mammals and that are thought to be important for the establishment and maintenance of the infection. T…
Solution NMR structure of Borrelia burgdorferi outer surface lipoprotein BBP28, a member of the mlp protein family.
2020
Lyme disease is the most widespread vector‐transmitted disease in North America and Europe, caused by infection with Borrelia burgdorferi sensu lato complex spirochetes. We report the solution NMR structure of the B. burgdorferi outer surface lipoprotein BBP28, a member of the multicopy lipoprotein (mlp) family. The structure comprises a tether peptide, five α‐helices and an extended C‐terminal loop. The fold is similar to that of Borrelia tunicate outer surface protein BTA121, which is known to bind lipids. These results contribute to the understanding of Lyme disease pathogenesis by revealing the molecular structure of a protein from the widely found mlp family. This article is protected …