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Isolation and identification of two Serratia marcescens strains from silkworm, Bombyx mori
Yiling Zhang1,2,3,4, Ruisha Shang1, Jiao Zhang1
1College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212021, China.
Abstract:
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 (LC50) 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.
Insights
Two new bacterial strains, ZJ-1 and ZJ-2, were identified as Serratia marcescens from silkworms. ZJ-2, a low-toxicity strain, efficiently produces red pigment, offering potential for industrial applications.
Area of Science:
- Bacteriology
- Sericulture Science
- Biotechnology
Background:
- Bacterial septicemia causes significant economic losses in the sericulture industry.
- Isolation and characterization of novel bacterial strains are crucial for disease management and biotechnological applications.
Purpose of the Study:
- To isolate and identify pathogenic bacterial strains from diseased silkworms.
- To characterize the isolated strains, Serratia marcescens ZJ-1 and ZJ-2, for their biochemical properties, pigment production, and virulence.
- To evaluate the potential of ZJ-2 as a safe and efficient source for red pigment production.
Main Methods:
- Isolation of bacterial strains from dead silkworms.
- Phenotypic and genotypic analyses for bacterial identification.
- Biochemical tests and pigment analysis at different temperatures.
- Determination of lethal concentration 50 (LC50) to assess virulence.
Main Results:
- Two strains, ZJ-1 and ZJ-2, were identified as closely related to Serratia marcescens.
- ZJ-1 exhibited standard S. marcescens characteristics, while ZJ-2 showed distinct variations in metabolic capabilities.
- ZJ-2 produced red pigment at 37°C, unlike ZJ-1, and possessed lower virulence (higher LC50) than ZJ-1.
Conclusions:
- ZJ-1 and ZJ-2 represent distinct strains of Serratia marcescens.
- ZJ-2 is a promising candidate for safe and efficient red pigment production due to its low toxicity and pigment-generating ability.
- Further molecular research is required to elucidate the mechanisms of pigment production and infection by ZJ-2.
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