Bioactive compounds produced by cyanobacteria

Cyanobacteria produce a large number of compounds with varying bioactivities. Prominent among these are toxins: hepatotoxins such as microcystins and nodularins and neurotoxins such as anatoxins and saxitoxins. Cytotoxicity to tumor cells has been demonstrated for other cyanobacterial products, including 9-deazaadenosine, dolastatin 13 and analogs. A number of compounds in cyanobacteria are inhibitors of proteases — micropeptins, cyanopeptolins, oscillapeptin, microviridin, aeruginosins- and other enzymes, while still other compounds have no recognized biological activities. In general cyclic peptides and depsipeptides are the most common structural types, but a wide variety of other types are also found: linear peptides, guanidines, phosphonates, purines and macrolides. The close similarity or identity in structures between cyanobacterial products and compounds isolated from sponges, tunicates and other marine invertebrates suggests the latter compounds may be derived from dietary or symbiotic blue-green algae.     

The effect of preparative protocol on the cytoskeleton ultrastructure observed in extracted whole-mount BHK cells

Extracted BHK cells (baby hamster kidney) were prepared for electron microscopy by air-drying (with Freon 113), critical-point-drying, and freeze-drying. Variations in the drying procedures had a marked effect on the resultant cytoskeleton ultrastructure. Air drying had to be done in a Freon-saturated atmosphere, residual water had to be removed from the dehydrating solutions and carbon dioxide for critical-point-dried specimens, and freeze-drying had to be done at temperatures lower than -90 degrees C. Failure to exercise these precautions resulted in a cytoskeleton ultrastructure artifact, possibly caused by fusion of the cytoskeleton filaments.