Background and Aim: Hemolysin as a pore forming toxin is an important virulence factor in many bacteria especially Bacillus species. This toxin causes lysis of erythrocytes by destroying cell membrane. According to its concentration, hemolysin can induce apoptosis or necrosis in host cells. The aim of this study was to evaluate the hemolytic activity and hemolysin characteristics of a naturally occurring bacterium isolated from shrimp’s farm for further anticancer studies. Methods: shrimp farm samples had been collected in previous studies and kept in laboratory stock cultures. After recultivation of samples, hemolysin screening was performed on blood agar medium and bacteria with highest alpha zone were selected, purified and designated as HGM96. Bacterium (HGM96) was molecularly identified by 16S ribosomal RNA gene sequencing. Then HGM96 hemolysin was extracted by ammonium sulphate precipitation. Bradford assay was performed for measuring the protein concentration and Zymogram and SDS-PAGE methods were respectively used to purify and measure the molecular weight of hemolysin. Results: molecular identification showed up to %99 homology of HGM96 strain with Bacillus zhangzhouensis. The hemolysin was successfully extracted and its lysis properties were confirmed. SDS-PAGE method showed that HGM96 is able to produce two hemolysins with molecular weights of 54 and 18 kDa. Conclusion: isolated bacillus strain from aquaculture water of shrimp presented a strong hemolytic activity and the ability of this toxin in pore formation and apoptosis induction can be a valuable tool in cancer studies.

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