Dr. Mark Strom
Program Manager
Program Staff Directory
Microbiology Home
Molecular Pathogenesis
Aeromonas salmonicida
Renibacterium salmoninarum
R. salmoninarum Genome
Project
Vibrio vulnificus
Diagnostics development,
identification tools
Applied Studies
BKD vaccines
and chemotherapeutics
Disease Diagnostics
and Pathology
Program Publications
• By year
• By document type
|
|
|
Current Research - Aeromonas salmonicida
|
CRIS AD-421 Research Reports Submitted for 98-35204-6979 on 12/14/99
Project Number: WNR-9802272
Grant Number: 98-35204-6979
CRIS Number: 0181273
ROLE OF TYPE IV PILI IN AEROMONAS SALMONICIDA PATHOGENESIS AND USE AS A VACCINE
Investigators:
Strom, M. S.
Termination Date: 11/30/00
Reporting period: 10/01/98 to 09/30/99
Progress Report:
The goal of this research is to clone and
characterize the genes that encode factors
involved in expression of type IV pili and
extracellular protein secretion from the pathogen
Aeromonas salmonicida, which causes the disease
furunculosis in salmonid fish. Pili are fibers
that protrude from bacterial cells that are often
involved in the initial attachment or
colonization of pathogenic bacteria to host
cells. These same bacteria are often capable of
secreting a number of toxins and degradative
enzymes involved in virulence through a related
pathway. A demonstration that these factors are
important for the pathogenesis of A. salmonicida
could form the basis for an effective vaccine
against the pathogen. Cloning and DNA sequencing
of the tapABCD gene cluster have been completed.
The DNA sequences and encoded protein
translations have been deposited in the Genbank
Sequence Database (accession numbers AF059248 and
AF059249). The genes and their encoded proteins
are highly homologous to previously characterized
type IV pilins and associated proteins involved
in pilus biogenesis from A. hydrophila, Vibrio
vulnificus, and Pseudomonas aeruginosa. However,
even though amino acid sequences of TapA from A.
hydrophila Ah65 and A. salmonicida A450 share 64%
identity, antisera specific for the A. hydrophila
TapA does not recognize TapA from A. salmonicida.
Plasmid constructs carrying copies of
insertionally inactivated tapA and tapD genes in
a suicide vector have been completed. Specific
tapA and tapD mutants of A. salmonicida have been
constructed by allelic exchange using these
clones. A tapA:FLAG fusion construct was made in
order to purify recombinant TapA protein for
antisera preparation. An in vitro bacterial
adherence assay was adapted for A. salmonicida
and the salmonid cell line Chinook Salmon
Embryo-214 (CHSE-214). This will be used to
measure the role of TapA in colonization of
tissue cells.
Impact:
A demonstration that type IV pili are involved in
the intial interaction or colonization of the
salmonid fish host in infections caused by
Aeromonas salmonicida could potentially lead to
the development of a safe, efficacious, and easy
to administer vaccine against furunculosis.
Publications:
(No publications reported.)
|
