Phani Victor, Rao Uma
Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India.
J Nematol. 2018 Sep 3;50(2):91-98. doi: 10.21307/jofnem-2018-022.
Pasteuria penetrans is a Gram-positive, endospore forming soil bacterium, infecting root-knot nematodes, Meloidogyne spp. Being obligate in nature, the bacterium is not easily grown in vitro, and the in vivo culturing technique is relied on the soil-based microcosm since long. Hence, culturing of P. penetrans using CYG germination pouches as a soil-less medium for plant growth, promises to provide a contamination free environment along with ease in isolation of infected females from the plant roots. Additionally, this method increases the percentage of P. penetrans infected nematode females as compared with the soil-based system. Schematic observation of all the life stages of P. penetrans was documented, which revealed chronological fragmentation of vegetative microcolony inside the nematode body demonstrating the formation of some stages not reported earlier. Further, germination of endospores attached to infective juveniles was found to be most likely asynchronous as single female nematode contained most of the developing stages of P. penetrans concurrently. Additionally, the effect of an antibiotic, streptomycin sulfate was evaluated for effects on the growth and development of the bacterium at different concentrations. Higher doses of antibiotic were found to exert a negative impact on the development of P. penetrans , which shows the incompatibility of Pasteuria and streptomycin sulfate.
穿透巴氏杆菌是一种革兰氏阳性、形成芽孢的土壤细菌，可感染根结线虫（Meloidogyne spp.）。由于该细菌本质上是专性寄生的，不易在体外培养，长期以来其体内培养技术依赖于基于土壤的微观生态系统。因此，使用CYG发芽袋作为植物生长的无土培养基来培养穿透巴氏杆菌，有望提供一个无污染的环境，同时便于从植物根部分离受感染的雌虫。此外，与基于土壤的系统相比，这种方法提高了穿透巴氏杆菌感染线虫雌虫的比例。记录了穿透巴氏杆菌所有生命阶段的示意图观察结果，这揭示了线虫体内营养微菌落的按时间顺序的碎片化，表明形成了一些先前未报道的阶段。此外，发现附着在感染性幼虫上的芽孢萌发很可能是异步的，因为单个雌虫同时包含了穿透巴氏杆菌的大部分发育阶段。此外，评估了抗生素硫酸链霉素在不同浓度下对该细菌生长和发育的影响。发现较高剂量的抗生素对穿透巴氏杆菌的发育有负面影响，这表明巴氏杆菌与硫酸链霉素不相容。
