细菌几丁质酶基因的表达调控

Regulation of chitinase genes expression in bacteria

几丁质酶可以降解几丁质,广泛存在于各类微生物中。几丁质的降解产物几丁寡糖在医药、食品及农业生防领域有很重要的应用价值及广泛的应用前景。细菌在利用几丁质时,需要先分泌几丁质酶,将几丁质降解成几丁寡糖或单体,再通过特异的转运系统送进细胞而被利用。胞内的几丁质降解产物作为特定的信号分子,可以激活或阻遏相应chi基因的转录,从而影响细菌几丁质酶的合成。在各种调节蛋白及应答元件的参与下,细菌几丁质酶的合成受到精密的控制。文章以链霉菌和大肠杆菌为代表综述了细菌在转运系统和基因表达两个层面上控制几丁质酶合成的最新研究进展。

Chitinases,which can hydrolyze chitin,occur in a wide range of microorganisms including viruses,bacteria,and fungi.The derivatives of chitin are potentially useful in several areas such as food processing,medicines,and biological control in agriculture.Some bacteria can uptake and utilize chitin as carbon source by secreting chitinase.The chitin is de-graded into chito-oligosaccharides [（GlcNAc）n] or N-acetylglucosamine（GlcNAc） by chitinases,and then the chitin deriva-tives are transferred into cells by specific transport systems of bacteria.The intracellular chitin derivatives activate or sup-press the transcription of a series of chi genes and affect the amount of chitinase.The expression of chitinase genes are strictly regulated by various regulatory factors and responsive cis-acting elements.The present review will focus on the transport system and the regulation of chitinase genes expression in bacteria.