Chitin Heterodisaccharide, Released from Chitin by Chitinase and Chitin Oligosaccharide Deacetylase, Enhances the Chitin-Metabolizing Ability of Vibrio parahaemolyticus

Abstract

<i>Vibrio parahaemolyticus</i> RIMD2210633 secretes both chitinase and chitin oligosaccharide deacetylase and produces β-<i>N</i>-acetyl-d-glucosaminyl-(1,4)-d-glucosamine (GlcNAc-GlcN) from chitin. Previously, we reported that GlcNAc-GlcN induces chitinase production by several strains of <i>Vibrio</i> harboring chitin oligosaccharide deacetylase genes (T. Hirano, K. Kadokura, T. Ikegami, Y. Shigeta, et al., Glycobiology 19:1046-1053, 2009). The metabolism of chitin by <i>Vibrio</i> was speculated on the basis of the findings of previous studies, and the role of chitin oligosaccharide produced from chitin has been well studied. However, the role of GlcNAc-GlcN in the <i>Vibrio</i> chitin degradation system, with the exception of the above-mentioned function as an inducer of chitinase production, remains unclear. <i>N</i>,<i>N</i>'-Diacetylchitobiose, a homodisaccharide produced from chitin, is known to induce the expression of genes encoding several proteins involved in chitin metabolism in <i>Vibrio</i> strains (K. L. Meibom, X. B. Li, A. Nielsen, C. Wu, et al., Proc Natl Acad Sci U S A 101:2524-2529, 2004). We therefore hypothesized that GlcNAc-GlcN also affects the expression of enzymes involved in chitin metabolism in the same manner. In this study, we examined the induction of protein expression by several sugars released from chitin using peptide mass fingerprinting and confirmed the expression of genes encoding enzymes involved in chitin metabolism using real-time quantitative PCR analysis. We then confirmed that GlcNAc-GlcN induces the expression of genes encoding many soluble enzymes involved in chitin degradation in <i>Vibrio parahaemolyticus</i> Here, we demonstrate that GlcNAc-GlcN enhances the chitin-metabolizing ability of <i>V. parahaemolyticus</i><b>IMPORTANCE</b> We demonstrate that β-<i>N</i>-acetyl-d-glucosaminyl-(1,4)-d-glucosamine (GlcNAc-GlcN) enhances the chitin-metabolizing ability of <i>V. parahaemolyticus</i> Members of the genus <i>Vibrio</i> are chitin-degrading bacteria, and some species of this genus are associated with diseases affecting fish and animals, including humans (F. L. Thompson, T. Iida, and J. Swings, Microbiol Mol Biol Rev 68:403-431, 2004; M. Y. Ina-Salwany, N. Al-Saari, A. Mohamad, F.-A. Mursidi, et al., J Aquat Anim Health 31:3-22, 2019). Studies on <i>Vibrio</i> are considered important, as they may facilitate the development of solutions related to health, food, and aquaculture problems attributed to this genus. This report enhances the current understanding of chitin degradation by <i>Vibrio</i> bacteria.