Detection of heavy metal resistance bioluminescence bacteria using microplate bioassay method

Effects of different heavy metals on Vibrio harveyi, V. fischeri, Photobacterium phosphoreum and P. leiognathi were examined. Checkerboard assay was used for the detection of the natural metal tolerance levels of a large number of marine luminous eubacteria. 57 strains of luminous bacteria were investigated for their natural patterns of heavy metal tolerance. The behaviors of these strains were not homogeneous with respect to all metals tested, even within the strains belonging to the same genus. At least 1 to 4 different MICs were detected for every metal except barium and cobalt. Isolated bacteria were tested for the presence of plasmids using the modified alkaline lysis method, was effective for identification of plasmids of different sizes. This study revealed the frequency of the occurrence of plasmids in heavy metal resistance bacteria and inferred that plasmids are highly ubiquitous and predominant in most heavy metal resistant bacteria.