Journal of Environmental Biology

Characterization of native Bacillus thuringiensis strains for cytotoxicity against human cancer cell lines

M.K. Oktay, B. Şahin and H. G?neş*

Department of Biology, Faculty of Science, Muğla Sıtkı Ko?man University, 48000, Muğla, Turkey

*Corresponding Author E-mail: haticegunes@mu.edu.tr

Key words

Bacillus thuringiensis

Cancer cell lines

Cyt genes

Cytotoxicity

Parasporin

Publication Data

Paper received : 14.08.2017

Revised received : 20.12.2017

Accepted : 05.02.2018

Abstract

Aim: The aim of this study was to characterize fourteen B. thuringiensis strains for cyt and parasporin gene contents as well as cytotoxicity of parasporal proteins against different cancer cell lines.?? ?

Methodology: PCR was applied for screening of cyt 1/cyt 2 and six different parasporin genes. In addition, cyt negative (non-cyt) nine Bt strains were tested for hemolytic activity. Non-cyt and non-hemolytic parasporal proteins from nine Bt strains were alkali solubilized and activated by proteinase- K for in vitro cytotoxic activities. ?

Results: Five Bt strains carried cyt gene whereas only one strain Bt-Ba14 harbored parasporin 2 gene and showed 37 kDa protein on SDS-PAGE. Non-cyt 9 Bt strains were confirmed to be non-hemolytic. MTT assay indicated that activated parasporal proteins (10 ?g ml^-1) displayed selective cytotoxicity against HeLa, PC-3 and A549 cancer cell lines compared to a normal cell line BEAS-2B. Parasporal protein from Bt-Ba14 exhibited the highest cytotoxicity against all three cancer cells, however, not to normal cell line and caused cytocidal activity similar to that observed with parasporins. ?

Interpretation: The study reported that non-cyt and non-hemolytic Bt strains from Turkey have parasporal proteins with cytotoxic activities against cancer cells.

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