Biomaterial Database

The ADP-ribosylating toxin, AexT, from Aeromonas salmonicida subsp. salmonicida is translocated via a type III secretion pathway. 2003

Sarah E Burr, and Katja Stuber, and Joachim Frey

Institute of Veterinary Bacteriology, University of Berne, CH-3012 Berne, Switzerland.

AexT is an extracellular ADP ribosyltransferase produced by the fish pathogen Aeromonas salmonicida subsp. salmonicida. The protein is secreted by the bacterium via a recently identified type III secretion system. In this study, we have identified a further 12 open reading frames that possess high homology to genes encoding both structural and regulatory components of the Yersinia type III secretion apparatus. Using marker replacement mutagenesis of aopB, the A. salmonicida subsp. salmonicida homologue of yopB in Yersinia, we demonstrate that the bacterium translocates the AexT toxin directly into the cytosol of cultured fish cells via this type III secretion pathway. An acrV mutant of A. salmonicida subsp. salmonicida displays a calcium-blind phenotype, expressing and secreting significant amounts of AexT even in the presence of CaCl2 concentrations as high as 10 mM. This acrV mutant is also unable to translocate AexT into the cytosol of fish cells, indicating AcrV is involved in the translocation process. Inactivation of either the aopB or acrV gene in A. salmonicida subsp. salmonicida (resulting in an inability to translocate AexT) is accompanied by a loss of cytotoxicity that can be restored by trans complementation. Finally, we present data indicating that preincubation of the wild-type bacteria with antibodies directed against recombinant AcrV-His protein provides fish cells protection against the toxic effects of the bacterium.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D002347	Carps	Common name for a number of different species of fish in the family Cyprinidae. This includes, among others, the common carp, crucian carp, grass carp, and silver carp.	Carassius carassius,Crucian Carp,Cyprinus,Grass Carp,Carp,Ctenopharyngodon idellus,Cyprinus carpio,Hypophthalmichthys molitrix,Koi Carp,Silver Carp,Carp, Crucian,Carp, Grass,Carp, Koi,Carp, Silver,Carps, Crucian,Carps, Grass,Carps, Silver,Crucian Carps,Grass Carps,Silver Carps
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D000333	Aeromonas	A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs singly, in pairs, or in short chains. Its organisms are found in fresh water and sewage and are pathogenic to humans, frogs, and fish.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001425	Bacterial Outer Membrane Proteins	Proteins isolated from the outer membrane of Gram-negative bacteria.	OMP Proteins,Outer Membrane Proteins, Bacterial,Outer Membrane Lipoproteins, Bacterial
D001427	Bacterial Toxins	Toxic substances formed in or elaborated by bacteria; they are usually proteins with high molecular weight and antigenicity; some are used as antibiotics and some to skin test for the presence of or susceptibility to certain diseases.	Bacterial Toxin,Toxins, Bacterial,Toxin, Bacterial
D015964	Gene Expression Regulation, Bacterial	Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.	Bacterial Gene Expression Regulation,Regulation of Gene Expression, Bacterial,Regulation, Gene Expression, Bacterial
D017422	Sequence Analysis, DNA	A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.	DNA Sequence Analysis,Sequence Determination, DNA,Analysis, DNA Sequence,DNA Sequence Determination,DNA Sequence Determinations,DNA Sequencing,Determination, DNA Sequence,Determinations, DNA Sequence,Sequence Determinations, DNA,Analyses, DNA Sequence,DNA Sequence Analyses,Sequence Analyses, DNA,Sequencing, DNA
D017686	Oncorhynchus mykiss	A large stout-bodied, sometimes anadromous, TROUT found in still and flowing waters of the Pacific coast from southern California to Alaska. It has a greenish back, a whitish belly, and pink, red, or lavender stripes on the sides, with usually a sprinkling of black dots. It is highly regarded as a sport and food fish. Its former name was Salmo gairdneri. The sea-run rainbow trouts are often called steelheads. Redband trouts refer to interior populations of rainbows.	Salmo gairdneri,Steelhead,Trout, Rainbow,Trout, Redband,Rainbow Trout,Redband Trout,Steelheads