Duplication and variation of the thermostable direct haemolysin (<i>tdh)</i> gene in <i>Vibrio parahaemolyticus</i>

この論文をさがす

抄録

<jats:title>Summary</jats:title><jats:p>The relationship between phenotypic variation and nucleotide sequence variation of the gene encoding <jats:italic>Vibrio parahaemolyticus</jats:italic> thermostable direct haemolysin (<jats:italic>tdh</jats:italic> gene) was examined. Strains showing a typical haemolysin‐positive phenotype carried two chromosomal gene copies (designated <jats:italic>tdh1</jats:italic> and <jats:italic>tdh2)</jats:italic> while fdh‐gene‐positive strains showing a weakly positive or negative haemolysin phenotype possessed only a single chromosomal gene copy. Both gene copies from a typical haemolysin‐positive strain were cloned and sequenced and possessed 97.2% homo‐logy. Comparison of the amino acid sequence predicted from the nucleotide sequence with the protein sequence determined by Edman degradation as well as construction of a <jats:italic>tdh1</jats:italic>‐deficient yet haemolytic strain of <jats:italic>V. parahaemolyticus</jats:italic> suggest that the <jats:italic>tdh2</jats:italic> locus is primarily responsible for the haemolytic phenotype. Two other <jats:italic>tdh</jats:italic> gene copies were cloned from a phenotypically negative strain which was unusual in that it contained one gene copy on a plasmid (designated <jats:italic>tdh4)</jats:italic> in addition to a single copy on the chromosome (<jats:italic>tdhS).</jats:italic> Both <jats:italic>tdh3</jats:italic> and <jats:italic>tdh4</jats:italic> were expressed in <jats:italic>Escherichia coli</jats:italic> and TDHs with haemolytic activity were produced. These gene copies were sequenced and shared 96.7% homology with the <jats:italic>tdh1</jats:italic> gene. The <jats:italic>V. parahaemolyticus</jats:italic> strain carrying <jats:italic>tdh3</jats:italic> and <jats:italic>tdh4</jats:italic> gene copies did not produce detectable amounts of <jats:italic>tdh</jats:italic>‐specific RNA transcript. It seems, therefore, that differences in the transcriptional control are primarily responsible for the differences seen in haemolytic phenotype.</jats:p>

収録刊行物

被引用文献 (11)*注記

もっと見る

詳細情報 詳細情報について

問題の指摘

ページトップへ