ABSTRACT
Salmonid rickettsial septicemia, caused by Piscirickettsia salmonis, causes major mortalities in Chilean salmonid aquaculture and is an increasing problem in Atlantic salmon in Ireland and Scotland. Analysis of 16S-to-23S internal transcribed sequences and 16S ribosomal DNA (rDNA) shows that Irish isolates of P. salmonis form two new groups of the organism while Scottish isolates cluster together with Norwegian and Canadian isolates from Atlantic salmon.
Subject(s)
Piscirickettsiaceae/isolation & purification , Salmo salar/microbiology , Animals , Base Sequence , Cloning, Molecular , DNA, Bacterial/isolation & purification , DNA, Ribosomal/chemistry , Ireland , Molecular Sequence Data , Piscirickettsiaceae/classification , Piscirickettsiaceae/genetics , RNA, Ribosomal, 16S/genetics , ScotlandABSTRACT
The occurrence of brown ring disease (BRD) in farmed Manila clams Ruditapes philippinarum is seasonal. Development of the disease is believed to require the presence of the infective agent Vibrio tapetis and particular environmental conditions. This paper studies the effect of salinity (20 to 40 per thousand) on measurable immune parameters of Manila clams, and the progression of BRD in experimentally infected individuals. At 20 per thousand salinity, the total haemocyte count was reduced and disease prevalence was highest. At 40 per thousand salinity significantly fewer clams presented signs of BRD, and this was correlated with increases in the total haemocyte count, hyalinocyte count, phenoloxidase levels and phagocytic activity of haemocytes. Inoculation of clams with V. tapetis did not have a significant effect on the immune parameters measured. Thus, this laboratory-based study relates environmental stress to disease development.
Subject(s)
Bivalvia/immunology , Bivalvia/microbiology , Hemocytes/physiology , Seawater/analysis , Vibrio/immunology , Analysis of Variance , Animals , Aquaculture , Bivalvia/physiology , Cytotoxicity Tests, Immunologic , France , Immunocompetence/physiology , Levodopa/physiology , Phagocytosis/physiology , Vibrio/physiologyABSTRACT
Bacteroides forsythus is a Gram negative anaerobe associated with human periodontal disease. Heat shock proteins are immunodominant antigens in bacteria that can elicit strong and protective immune responses. The gene specifying the GroEL protein (hsp60, heat shock protein 60) of B. forsythus was isolated by PCR amplification using consensus primers based upon published nucleotide sequences of the groEL genes of several bacterial species. Translation of the gene sequence predicts a protein of 544 amino acids in length with a molecular mass of 58 kDa. B. forsythus GroEL demonstrates identities of 50 to 81% with the predicted amino acid sequences of GroEL proteins of several bacterial species and the human mitochondrial P1 protein.
