Screening and identification of an anti-bacterial and cytotoxic marine halophilic strain XD20
- Author:
Jun MU
1
Author Information
1. Department of Biochemistry and Molecular Biology
- Publication Type:Journal Article
- From:
Academic Journal of Second Military Medical University
2006;27(1):8-11
- CountryChina
- Language:Chinese
-
Abstract:
Objective: To isolate and screen the active marine microorganisms from East China Sea and to identify the phenotypes of the isolated active strains. Methods: The samples were widely collected from East China Sea and the active strains were screened out through an anti-bacterial model and a cytotoxic model. The isolated strains were subjected to phenotypical study, salt-aggregation test and rDNA ITS sequencing. Neighbor-joining phylogenetic trees were drawn by comparing the results of rDNA ITS sequencing with sequences of described species in the BLAST server of the National Center for Biotechnology Information (NCBI). One of the strains, subsequently named XD20, was identified to species level. Results: XD20, a halophilic strain with a highest tolerable salt concentration of 10.0% and suitable concentration range of 2.5% to 7.5%, was collected and isolated on the site of C01 (122°26′30″, 30°43′48″) 30 meters under water. XD20 showed an inhibitory effect on the growth of Candida albicans and a cytotoxic activity toward SMMC7721 and HeLa cells. XD20 produced arthroconidia by mycelium break and the arthroconidia had similar size and morphology to those of Wallemia sebi. rDNA ITS sequencing showed that the sequence of XD20 had a higher similarity to those of Wallemia sebi and the differences were located in ITS1 and ITS2 areas, both belong to variable region. Conclusion: XD20, an active halophilic strain fungus, has been obtained from the sea for the first time, and has been identified to be Wallemia sebi (Fr.) Arx.
