Effect of environmental factors on expression and activity of chitinase genes of vibrios with special reference to Vibrio cholerae.
OBJECTIVE
The aim of this study was to investigate the distribution and inducibility of chitinase genes in vibrios and the effect of environmental factors on the expression level and activity of chitinase genes in Vibrio cholerae strains.


RESULTS
Chitin agar plate assays showed that V. cholerae strains were more chitinolytic than non-cholerae vibrios. All of the identified or putative chitinase genes were expressed in V. cholerae (four strains) but not in non-cholerae vibrios (seven species/strains) under standard laboratory growth conditions. In non-cholerae vibrios, these genes were induced by chitin, its monomer N-acetyl-d-glucosamine and on exposure to rabbit intestine, while in V. cholerae strains, these genes showed significant variation in expression levels. To study the effects of environmental factors on the expression and activity of chitinase genes in V. cholerae, bacteria were cultured in different pH, temperature, sodium chloride and nutrients. RT-PCR analysis showed that lower temperatures and higher pH, salinity and nutrition favoured expression of these genes, while their activity increased under higher nutrition content and salinity.


CONCLUSIONS
Chitinase genes are distributed in all the relatively small number of strains studied here, and biotic and abiotic factors have significant role in the induction, expression level and activity of this gene family in vibrios.


CONCLUSIONS
Chitinases have important applications especially in recycling of chitin. Vibrios can be used as chitinolytic agents, using suitable culture conditions that maximize the expression and activity of these genes.
Bhowmick
R
R
Division of Biochemistry, National Institute of Cholera and Enteric Diseases, Kolkata, India.
Ghosal
A
A
Chatterjee
N S
NS
D000117:Acetylglucosamine / Q000494:pharmacology; D000818:Animals; D001431:Bacteriological Techniques; D002688:Chitinases / Q000235:genetics* / Q000378:metabolism; D003470:Culture Media; D004305:Dose-Response Relationship, Drug; D005502:Food; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005798:Genes, Bacterial; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007082:Ileum / Q000382:microbiology; D008297:Male; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012965:Sodium Chloride / Q000494:pharmacology; D013696:Temperature; D014733:Vibrio / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D014734:Vibrio cholerae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*
D003470:Culture Media; D012965:Sodium Chloride; D002688:Chitinases; D000117:Acetylglucosamine