Zhang Yiling, Shang Ruisha, Zhang Jiao, Li Junhao, Zhu Guanyu, Yao Mingshuai, Sun Jiancheng, Shen Zhongyuan
College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212021, China.
The Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, 212021, China.
Antonie Van Leeuwenhoek. 2020 Sep;113(9):1313-1321. doi: 10.1007/s10482-020-01442-1. Epub 2020 Jun 30.
Bacterial septicemia commonly occurs and usually cause huge losses in sericulture industry. Here, two pathogenic bacterial strains were isolated from dead silkworm and named as ZJ-1 and ZJ-2. Phenotypic and genotypic analysis results revealed that both of these two strains are closely related to Serratia marcescens (S. marcescens). The morphological as well as physiological and biochemical characteristics of ZJ-1 were accordant with S. marcescens mentioned in Bergey's manual of determinative bacteriology, whereas ZJ-2 showed some discrepancies such as the utilization of malonate and starch, fermentation of maltose and sucrose, and tests of urease, etc. Surprisingly, ZJ-2 could produce red pigment at high temperature (37°) but ZJ-1 could not. Besides, by analyzing the lethal concentration 50 (LC) of ZJ-1 and ZJ-2, it was found that the virulence of ZJ-2 was lower than that of ZJ-1. These results revealed that ZJ-1 and ZJ-2 were two different strains of S. marcescens and that ZJ-2 was expected to be a safe (low-toxicity) and efficient strain for the production of red pigment. Nonetheless, further research in molecular level is needed to understand the regulation mechanism of pigment production and infection of ZJ-2.
细菌性败血症在养蚕业中普遍发生，通常会造成巨大损失。在此，从死蚕中分离出两株致病细菌菌株，命名为ZJ-1和ZJ-2。表型和基因型分析结果表明，这两株菌株均与粘质沙雷氏菌密切相关。ZJ-1的形态以及生理生化特征与《伯杰氏鉴定细菌学手册》中提到的粘质沙雷氏菌一致，而ZJ-2在丙二酸盐和淀粉利用、麦芽糖和蔗糖发酵以及尿素酶试验等方面存在一些差异。令人惊讶的是，ZJ-2在高温（37°）下可产生红色色素，而ZJ-1则不能。此外，通过分析ZJ-1和ZJ-2的半数致死浓度（LC），发现ZJ-2的毒力低于ZJ-1。这些结果表明，ZJ-1和ZJ-2是粘质沙雷氏菌的两个不同菌株，并且ZJ-2有望成为生产红色色素的安全（低毒）且高效的菌株。尽管如此，仍需要在分子水平上进行进一步研究，以了解ZJ-2色素产生和感染的调控机制。
