Search results for "toxin"

Relationships between Staphylococcus aureus genetic background, virulence factors, agr groups (alleles), and human disease

2002

ABSTRACT The expression of most Staphylococcus aureus virulence factors is controlled by the agr locus, which encodes a two-component signaling pathway whose activating ligand is an agr -encoded autoinducing peptide (AIP). A polymorphism in the amino acid sequence of the AIP and of its corresponding receptor divides S. aureus strains into four major groups. Within a given group, each strain produces a peptide that can activate the agr response in the other member strains, whereas the AIPs belonging to different groups are usually mutually inhibitory. We investigated a possible relationship between agr groups and human S. aureus disease by studying 198 S. aureus strains isolated from 14 asym…

Effet insecticide de Bacillus thuringiensis kurstaki et d’une toxine bactérienne, le Spinosad, à l’égard des blattes domestiques adultes (Blattella g…

2012

Les blattes sont très étudiées en raison de leur impact sur la santé humaine et animale, sur les cultures et l’habitat. Blattella germanica est une blatte domestique prédominante qui représente un vecteur potentiel des maladies. En raison de sa nuisance elle a fait l’objet de plusieurs études, en vue d’une lutte efficace. Ces dernières années, une nouvelle approche toxicologique est apparue, elle consiste à développer de nouveaux insecticides issus essentiellement des molécules biologiques telles que les plantes et les microorganismes comme les champignons et les bactéries. Dans cette étude on s’est intéressé aux effets induits par le Bacillus thuringiensiskurstaki sur les adultes de B. ger…

Effects of adjuvants of the cholera toxin family on CD4 + T cell responses in a murine model of intrarectal immunization with rotavirus-like particles

2011

Mucosal immunization is an important goal of vaccine development to protect against pathogens that use mucosa as portals of entry. However, the use of non-replicating antigens requires the addition of adjuvants.Cholera-like enterotoxins, cholera toxin (CT) from Vibrio cholerae and the heat-labile enterotoxin (LT) from toxinogenic strains of E. coli, as well as the mutant LR-192G and their B subunits (CTB and LTB) have been shown to increase immune responses against unrelated co-administered antigens by mucosal routes. However, their mechanism of action is very complex and not completely understood and differences exist between holotoxins and B subunits and within molecules, differences exis…

Ecological role of mycotoxins produced by Fusarium graminearum : consequences of the presence of deoxynivalenol (DON) in crop residues on the soil mi…

2012

Fusarium graminearum is a plant pathogenic fungus, causing devastating disease “Fusarium head blight” (FHB) in cereals including wheat and maize. It also contaminates the grains with mycotoxins including deoxynivalenol (DON) which are toxic to human and animals. This disease has resulted in the serious losses in grain yield and quality. We established through a first bibliographic review that during off season fungus survives saprophytically on the crop residues (ecological habitat) and serves as primary inoculum for the next season crop. However, we noticed also that the literature was poor about the role mycotoxins could play in the establishment of F. graminearum in such a habitat. The m…

Impact of deoxynivalenol on soil microflora and fauna

2012

F. graminearum is an important pathogen that causes head blight of cereal crops as wheat and maize. It also produces the mycotoxins (as Deoxynivalenol=DON) which are toxic to the human and animals. During the off season the pathogen survives in the soil, on weeds and in crop residues. A 24 weeks study was conducted in controlled conditions (microcosms of natural soil, 17 °C, 80% WHC) to test whether the presence of DON in the wheat crop residues gives competitive advantage to F. graminearum over the other soil microflora and fauna to survive and develop a primary inoculum during the decomposition process. This study was carried out in the presence of the whole soil biota (i.e. fungi, bacter…

Étude du développement saprophyte de [i]F. graminearum[/i] champignon pathogène du blé et producteur de mycotoxines

2009

SPE affiche, résumé; Troisième plante cultivée au monde derrière le maïs et le riz, première en ce qui concerne les échanges commerciaux, le blé est l’un des aliments prépondérants en production animale et les produits issus de sa transformation sont à la base de l’alimentation humaine. La fusariose est l’une des principales pathologies fongiques touchant les cultures de blé : elle provoque notamment un dessèchement des épis touchés. Un « pool » de champignons appartenant aux genres Fusarium et Microdochium est responsable de cette maladie. Celle-ci est connue depuis longtemps puisque F. graminearum, l’agent principal de la pathologie, a été décrit en 1839 (Schwabe, Flora Anhaltina 2). Outr…

Étude du développement saprophyte de Fusarium graminearum, champignon pathogène du blé et producteur de mycotoxines

2010

National audience; Troisième plante cultivée au monde derrière le maïs et le riz, première en ce qui concerne les échanges commerciaux, le blé est l’un des aliments prépondérants en production animale et les produits issus de sa transformation sont à la base de l’alimentation humaine. La fusariose est l’une des principales pathologies fongiques touchant les cultures de blé : elle provoque notamment un dessèchement des épis touchés. Un « pool » de champignons appartenant aux genres Fusarium et Microdochium est responsable de cette maladie. Celle-ci est connue depuis longtemps puisque F. graminearum, l’agent principal de la pathologie, a été décrit en 1839 (Schwabe, Flora Anhaltina 2). Outre …

Ecological role of mycotoxin and consequences of the presence of mycotoxins in crop residues on the survival and pathogenic activity of Fusarium gram…

2010

Mechanisms of protection against aflotoxin B1 genotoxycity in rats treated by organosulfur compounds from garlic

2002

International audience

Detection of Escherichia coli strains producing cytotoxic necrotizing factor type two (CNF2) by enzyme-linked immunosorbent assay

1994

Sheep and rabbit antisera were produced against lysates of E. coli strain 711 (pVir). This K-12 strain carries the Vir plasmid which codes for Cytotoxic Necrotizing Factor type 2 (CNF2). Immunoglobulin G (IgG) fractions of both immune sera were subsequently purified by a two-step precipitation method. To increase the specificity for CNF2, the sheep IgG preparation was extensively adsorbed against both a sonicated extract of isogenic K-12 strain 711 and intact phenol-treated cells of vaccine strain 711 (pVir). An enzyme-linked immunosorbent assay (ELISA) was developed to detect clinical isolates of E. coli producing CNF2, using the final preparations of rabbit and sheep IgG in a double sandw…