Search results for "Virulence factors"
showing 7 items of 67 documents
New Insight into Immunity and Immunopathology of Rickettsial Diseases
2011
Human rickettsial diseases comprise a variety of clinical entities caused by microorganisms belonging to the generaRickettsia,Orientia,Ehrlichia, andAnaplasma. These microorganisms are characterized by a strictly intracellular location which has, for long, impaired their detailed study. In this paper, the critical steps taken by these microorganisms to play their pathogenic roles are discussed in detail on the basis of recent advances in our understanding of molecularRickettsia-host interactions, preferential target cells, virulence mechanisms, three-dimensional structures of bacteria effector proteins, upstream signalling pathways and signal transduction systems, and modulation of gene exp…
Virulence factor rtx in Legionella pneumophila, evidence suggesting it is a modular multifunctional protein
2008
Abstract Background The repeats in toxin (Rtx) are an important pathogenicity factor involved in host cells invasion of Legionella pneumophila and other pathogenic bacteria. Its role in escaping the host immune system and cytotoxic activity is well known. Its repeated motives and modularity make Rtx a multifunctional factor in pathogenicity. Results The comparative analysis of rtx gene among 6 strains of L. pneumophila showed modularity in their structures. Among compared genomes, the N-terminal region of the protein presents highly dissimilar repeats with functionally similar domains. On the contrary, the C-terminal region is maintained with a fashionable modular configuration, which gives…
Seroepidemiology of pertussis infection in an urban childhood population in Cameroon.
1991
In 1989, the prevalence of IgG antibodies to pertussis toxin (PT) in a sample of 367 unvaccinated apparently healthy children 5-14 years old was estimated by ELISA in Kumba City (Cameroon). Children were recruited using a systematic random sampling from six primary schools located in different districts of the city. The sample was representative of the various socioeconomic classes. The overall prevalence was 75%; it increased from 62% in 5 year old children to 81% in children 12-14 years old (P less than 0.01). IgG antibody prevalence was positively related to the family size. Children belonging to households of nine or more members had a 2.2-fold risk (C.I. 95 per cent = 1.1-4.6) of previ…
Plasmid diversity in Vibrio vulnificus biotypes.
2009
Vibrio vulnificus is a heterogeneous bacterial species that can be virulent for humans and fish. Virulence in fish seems to rely on a recently described plasmid that can be transmitted between strains, aided by a conjugative plasmid. The main objective of this work was to analyse the plasmid content of a wide collection of strains from the three biotypes of the species, as well as to identify putative conjugative and virulence plasmids by means of Southern hybridization with specific probes and sequence analysis of selected gene markers. We found 28 different plasmid profiles in a total of 112 strains, which were relatively biotype- or serovar-specific. Biotype 1 lacked high-molecular-mass…
Staphylococcus epidermidis virulences faktori un epidemioloģiskā nozīme
2016
Staphylococcus epidermidis svarīgākais virule nces faktors ir biofilmas veidošana. Lai diferencētu komensālos celmus no kolonizējošiem un invazīviem celmiem, pētījumā tika izmantotas fenotipiskās metodes, nosakot biofilmas veidošanu, antibiogrammu, un molekulārās bioloģijas metodes, nosakot virulences gēnus aap / ica A un mec A. Rezultāti liecina, ka biofilmu veidošana raksturīga klīniskajiem celmiem, statistiski ticami biežāk gēni aap/ica A bija noteikti klīniskajos S.epidermidis celmos, tie vis biežāk bija rezistenti pret meticilīnu (97,8%). S.epidermidis tipēšanai pirmo reizi tika pielietota MLST (multilokusu sekvenču tipēšana) metode. Pētījuma rezultāti ļauj secināt par S.epidermidis ge…
A novel intrinsically disordered outer membrane lipoprotein ofAggregatibacter actinomycetemcomitansbinds various cytokines and plays a role in biofil…
2017
Intrinsically disordered proteins (IDPs) do not have a well-defined and stable 3-dimensional fold. Some IDPs can function as either transient or permanent binders of other proteins and may interact with an array of ligands by adopting different conformations. A novel outer membrane lipoprotein, bacterial interleukin receptor I (BilRI) of the opportunistic oral pathogen Aggregatibacter actinomycetemcomitans binds a key gatekeeper proinflammatory cytokine interleukin (IL)-1b. Because the amino acid sequence of the novel lipoprotein resembles that of fibrinogen binder A of Haemophilus ducreyi, BilRI could have the potential to bind other proteins, such as host matrix proteins. However, from th…
Evolutionary Dynamics of Pathoadaptation Revealed by Three Independent Acquisitions of the VirB/D4 Type IV Secretion System in Bartonella
2017
The α-proteobacterial genus Bartonella comprises a group of ubiquitous mammalian pathogens that are studied as a model for the evolution of bacterial pathogenesis. Vast abundance of two particular phylogenetic lineages of Bartonella had been linked to enhanced host adaptability enabled by lineage-specific acquisition of a VirB/D4 type IV secretion system (T4SS) and parallel evolution of complex effector repertoires. However, the limited availability of genome sequences from one of those lineages as well as other, remote branches of Bartonella has so far hampered comprehensive understanding of how the VirB/D4 T4SS and its effectors called Beps have shaped Bartonella evolution. Here, we repor…