|Budget Amount *help
¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000)
Fiscal Year 2014: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2013: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2012: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
|Outline of Final Research Achievements
The fish pathogen Streptococcus iniae is classified into K+ (capsulated) and K- (non-capsulated) phenotypes. To clarify the structure of genetic loci for capsular polysaccharide (cps) biosynthesis of the phenotypes, PCR amplification of their cps gene clusters was conducted. As a result, 29 out of 40 strains of K- phenotype produced the amplicons whose length was 1~2 kbp longer than those of K+ phenotype and were found to harbor IS981 or other insertion sequence in or between their cps genes, suggesting this structure caused the inhibition of cps biosynthesis. When Japanese flounder Paralichthys olivaceus were challenged with S. iniae strains of K+ or K- phenotype, the bacteria that switched their phenotype were detected after 1 to 2 weeks in the challenged fish, indicating phenotypic switch is easily occurred in vivo.