Fine structure of the thermophilic blue-green alga Synechococcus lividus Copeland. A study of frozen–fractured–etched cells

The thermophilic unicellular blue-green alga, Synechococcus lividus, was studied by electron microscopy in thin sections and by the freeze-etching technique. Thin sections revealed subcellular structures like those observed by other authors in mesophilic blue-green algae. In the freeze-etched fractures similar results were obtained but, in addition, surface views of plasma and thylakoidal membranes were examined in detail. The many inclusions present in the freeze-etched preparations confirmed those displayed in thin sections and are interpreted as polyhedral, polyphosphate, and lipid bodies. Some unidentified osmiophilic granules and also phycobilisomes were seen.