Collapsing Aged Culture of the Cyanobacterium Synechococcus elongatus Produces Compound(s) Toxic to Photosynthetic Organisms
Figure 3
CM is harmful to photosynthetic microorganisms but not to heterotrophic bacteria.
(A) XAD-extract of CM was applied to variety of cyanobacteria and algae including S. elongatus, Anabaena PCC 7120, Calothrix PCC 7601, Chlamydomonas reinhardtii, Dunaliella salina and Chlorella vulgaris. Sensitivity was examined spectroscopically to detect the effect on pigmentation. Additional phytoplankton species were examined, as well (see Table S1). Substances extracted with XAD were dissolved in ethanol; this organic solvent was added to fresh medium (FM) in the control samples. (B) Escherichia coli, Staphylococcus aureus, Streptococcus faecalis and Bacillus cereus were inoculated into FM or CM. The number of colony forming units (CFU) following 12 h illumination in CM was normalized to CFU obtained following exposure to FM.
