Throughout evolution, one of the most ancient forms of aggression between cells or organisms has been the production of proteins or peptides affecting the permeability of the target cell membrane. This class of virulence factors includes the largest family of bacterial toxins, the pore-forming toxins (PFTs). PFTs are bistable structures that can exist in a soluble and a transmembrane state. It ...

Phosphatidylinositol glycan-A (PIGA) is a gene that encodes an element required for the first step in glycosylphosphatidylinositol (GPI) anchor assembly. Because PIGA is X-located, a single mutation is sufficient to abolish cell surface GPI-anchored protein expression. In this study, we investigated whether mutation of the PIGA gene could be exploited to identify mutator (Mut) phenotypes in can...

The alpha toxin produced by Clostridium septicum is a channel-forming protein that is an important contributor to the virulence of the organism. Chinese hamster ovary (CHO) cells are sensitive to low concentrations of the toxin, indicating that they contain toxin receptors. Using retroviral mutagenesis, a mutant CHO line (BAG15) was generated that is resistant to alpha toxin. FACS analysis show...

In this study, pathogenic Aeromonas hydrophila, A. veronii, and A. schubertii from fish were detected by multiplex TaqMan real-time PCR assay. The assay utilized three pairs of specific primers and three corresponding TaqMan probes designed to detect the aerolysin gene in A. hydrophila, the aerolysin gene in A. veronii, and the gyrB gene in A. schubertii. The specificity of the probe and primer...

Collagen-binding protein (CNBP) synthesized by Aeromonas veronii is located conserved within the subcellular fraction. The results of this study show that 98% of the total CNBP produced by Aer. veronii is present in the extracellular medium, and that the remaining CNBP is distributed either on the cell surface, within the periplasm or anchored on the outer membrane. CNBP is specifically secrete...

The binary toxin from Lysinibacillus sphaericus has been successfully used for controlling mosquito-transmitted diseases. An activation step shortens both subunits BinA and BinB before their interaction with membranes and internalization in midgut cells, but the precise role of this activation step is unknown. Herein, we show conclusively using three orthogonal biophysical techniques that proto...

In this paper, we studied the fate of endocytosed glycosylphosphatidyl inositol anchored proteins (GPI- APs) in mammalian cells, using aerolysin, a bacterial toxin that binds to the GPI anchor, as a probe. We find that GPI-APs are transported down the endocytic pathway to reducing late endosomes in BHK cells, using biochemical, morphological and functional approaches. We also find that this tra...

Aerolysin is one of the putative toxins in extracellular products (ECP) produced by Aeromonas hydrophila, an important pathogen of catfish. To better understand the molecular mechanism and mode of action of this toxin, proaerolysin-coding gene was cloned from the genomic DNA of an A. hydrophila strain, cultured from diseased channel catfish, and heterologously expressed in E. coli. Functional r...

In this work, we report likely recurrent horizontal (lateral) gene transfer events of genes encoding pore-forming toxins of the aerolysin family between species belonging to different kingdoms of life. Clustering based on pairwise similarity and phylogenetic analysis revealed several distinct aerolysin sequence groups, each containing proteins from multiple kingdoms of life. These results stron...