Journal of Bacteriology, September 1998, p. 4435-4441, Vol. 180, No. 17
0021-9193/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

The Otto Warburg Center for Biotechnology in
Agriculture and the Department of Plant Pathology and Microbiology,
Faculty of Agricultural, Food, and Environmental Quality Sciences, The
Hebrew University of Jerusalem, Rehovot 76100, Israel,1 and
School of Biology,
Received 25 March 1998/Accepted 18 June 1998
Quorum sensing control mediated by N-acyl homoserine
lactone (AHL) signaling molecules has been established as a key
feature of the regulation of exoenzyme production in many gram-negative bacteria. In Chromobacterium violaceum ATCC 31532 a
number of phenotypic characteristics, including production of the
purple pigment violacein, hydrogen cyanide, antibiotics, and
exoproteases are known to be regulated by the endogenous AHL
N-hexanoyl-L-homoserine lactone (HHL). In this
study we show that C. violaceum produces a set of
chitinolytic enzymes whose production is regulated by HHL. The
chitinolytic activity was induced in strains grown in the presence of
chitin as the sole carbon source and quantitated in the secreted
proteins by using p-nitrophenol analogs of disaccharide, trisaccharide, and tetrasaccharide oligomers of
N-acetylglucosamine. By using 4-methylumbelliferyl analogs
of the same oligomers of N-acetylglucosamine as substrates
for proteins separated and renatured by sodium dodecyl
sulfate-polyacrylamide gel electrophoresis, at least six enzymes were
detected: a chitobiase with high specificity to a dimeric substrate of
87 kDa, two N-acetylglucosaminidases with apparent
molecular masses of 162 and 133 kDa, two endochitinases of 108 and 67 kDa, and a chitobiosidase of 56 kDa. In addition, two unidentified
bands of >205 kDa were found where a tetrameric chitin derivative was
used as a substrate. A pleiotropic mini-Tn5 mutant of
C. violaceum (CV026) that is defective in HHL
production and other quorum-sensing-regulated factors was also found to
be completely deficient in chitinolytic activity. Growth of this mutant
on minimal medium with chitin supplemented with culture supernatant
from the C. violaceum wild-type strain or 10 µM synthetic HHL restored chitinase production to the level shown by the parental strain. These results constitute the most complete evidence so far for
regulation of chitinolytic activity by AHL signaling in a gram-negative
bacterium.
*
Corresponding author. Mailing address: The Hebrew
University, Otto Warburg Center for Biotechnology in Agriculture,
Faculty of Agriculture, P.O. Box 12, Rehovot 76100, Israel. Phone:
972-8-9481128. Fax: 972-8-9468785. E-mail:
chernin{at}agri.huji.ac.il.
Present address: Institute of Biological Sciences, University of
Wales, Aberystwyth, Ceredigion SY23 3DD, United Kingdom.
This article has been cited by other articles:
| Appl. Environ. Microbiol. | Infect. Immun. | Eukaryot. Cell |
|---|---|---|
| Mol. Cell. Biol. | J. Virol. | Microbiol. Mol. Biol. Rev. |
| ALL ASM JOURNALS |