Cytogenetic Study on Mitotic Cell Division in Allium cepa by Lead (Pb) and Chromium (Cr) Containing Bacterial Strain Isolated from Tannery Effluents of Bangladesh

In the present study, a bacterial strain capable of Pb and Cr detoxifi cation was isolated from tannery effl uents which was identifi ed as Myroides sp. through 16S rRNA gene sequencing. In the cytogenetic experiment, 100 and 600 μg/ml of lead and chromium were used as treatment for the root tips of Allium cepa and caused many chromosomal abnormalities such as abnormal chromosome position, damaged nucleus, breaks of chromosome bridges and fragments also occurred. Notably, sticky metaphase was found where sticky chromosomes indicated highly toxic, usually irreversible consequences leading to cell death. However, Myroides sp. treated supernatant, collected after day 7, used to treat Allium cepa tips showed less mitotic aberrations, nuclear degeneration and observed normal anaphase and telophase stage indicating possible metal detoxifying ability of the isolated strain. Furthermore, LC50 value was 64.63 μl/ml for Myroides sp. ABSTRACT Subject Area(s): MICROBIOLOGY | BIOLOGY