Pel R, van den Wijngaard A J, Epping E, Gottschal J C
Department of Microbiology, University of Groningen, Haren, The Netherlands.
J Gen Microbiol. 1990 Apr;136(4):695-704. doi: 10.1099/00221287-136-4-695.
The chitinolytic properties of a facultatively anaerobic bacterium isolated from the hindgut of plaice were compared with those of Clostridium sp. strain 9.1, a bacterium isolated from anoxic estuarine sediment. The chitinolytic enzyme systems of the gut isolate and strain 9.1 both released N,N'-diacetylchitobiose (NAG2) as the major hydrolysis end-product. During the hydrolysis of chitin, there was transient accumulation of a non-sedimentary chitin fraction which was not detectable by high-performance liquid chromatography. Growth on NAG2 repressed chitinase synthesis in the gut isolate but not in the Clostridium species. Thiol reagents were strongly inhibitory to the chitinase of the strict anaerobe but did not affect the hydrolytic enzymes of the gut isolate. When the two bacteria were cocultured with chitin as the sole carbon and energy source, Clostridium sp. strain 9.1 was always outcompeted. Experiments with batch and phauxostat cultures showed that the competitiveness of strain 9.1 could be improved dramatically by the inclusion in the cocultures of a non-chitinolytic bacterium capable of fermenting chitin oligomers. The cooperation between the oligomer-fermenting species and the Clostridium sp. is discussed in relation to the regulation of chitinolytic activity in the latter organism.
将从鲽鱼后肠分离出的兼性厌氧菌的几丁质分解特性与从缺氧河口沉积物中分离出的梭菌属菌株9.1的特性进行了比较。肠道分离菌和菌株9.1的几丁质分解酶系统均释放出N，N'-二乙酰壳二糖（NAG2）作为主要水解终产物。在几丁质水解过程中，有一个不可沉淀的几丁质组分短暂积累，高效液相色谱法无法检测到该组分。以NAG2为底物生长会抑制肠道分离菌中几丁质酶的合成，但对梭菌属细菌没有影响。硫醇试剂对严格厌氧菌的几丁质酶有强烈抑制作用，但不影响肠道分离菌的水解酶。当这两种细菌以几丁质作为唯一碳源和能源进行共培养时，梭菌属菌株9.1总是被淘汰。分批培养和恒化器培养实验表明，通过在共培养物中加入一种能够发酵几丁质寡聚物的非几丁质分解细菌，可以显著提高菌株9.1的竞争力。本文讨论了寡聚物发酵菌与梭菌属之间的合作与后者几丁质分解活性的调节之间的关系。
