XVI International Botanical Congess

This study questioned whether bacteria from communities co-occurring (M+) or not (M-) with the cyanobacterium Microcystis aeruginosa respond similarly to Microcystis products. 50 M+ bacteria (Lake Erie) and 50 M- bacteria (East Twin Lake, OH) were tested. Sensitivity to potential antibacterial compounds was tested. M- communities were significantly (p<0.05) more susceptible than M+ isolates. Microcystis exudate effects on 48-hour bacterial growth yields were compared. The M- community exhibited significantly lower growth yields (p<0.005) to Microcystis exudate than did the M+ strains. Finally, chemotactic response was compared. M+ bacteria showed significantly greater (p< 0.005) positive chemotaxis to Microcystis exudate compared to control conditions and to M- strains.