Document Type: Original Article
Department of Biotic Evolution- Marine Science Center, Basrah University, Basrah, Iraq
Department of Biology, Collage of Education for Pure Science, Basrah University, Basrah, Iraq
Chemotaxis is the movement of a single cell organism as a reaction to a chemical stimulation in its surrounding environment. Biofilm-forming bacteria are the cause for numerous major health and environmental problems. Bacterial extracts were proven to induce negative chemotaxis reaction against biofilm-forming bacteria and biofilm development. Therefore, using and enhancing these extracts are considered as promising methods in pharmaceutical production and environmental science. In this study, twenty Bacillus isolates and five biofilm-forming bacteria (targeted bacteria) isolates from different water and sediments samples of different areas in Basra province were biochemically diagnosed. Secondary metabolites of Bacillus isolates were extracted and analysed. Total proteins in the extracts were determined using Biuret method and the highest two isolates (BS8) and (BS14) with 13.78 and 12.02 g/l protein, respectively were chosen for the experiment. GC-MS results showed the existence of compounds with proven high antimicrobial properties such as type D-amino acids, N-cyclopropyl carbonyl-, butyl and esters such as d- proline, N-methoxycarbonyl, and pentyl ester. Afterwards, the chemotaxis nature of the purified extracts was studied. The results showed that both extracts had a negative chemotaxis toward the targeted bacteria represented by transparent halos without bacterial growth around the spot where secondary metabolites extracts of Bacillus subtilis were placed. K. kristinae was the most affected species in regards of growth inhibition zone diameter with 23 and 24 mm for (BS8) and (BS14) extracts respectively, while P. aeruginosa was the least affected with 19 and 18 mm for (BS8) and (BS14) extracts respectively.