Structures in a blue-green alga resembling prolamellar bodies

Summary Cells ofAnabaena (IUCC 380) from soil-water cultures 106 and 168 days after inoculation were fixed in 2% KMnO₄ and studied by electron microscopy. Thylakoid lattices morphologically similar to prolamellar bodies characteristic of etiolated higher plant chloroplasts were discovered. Prefixation sonication and centrifugation were eliminated as factors producing these lattices in the photosynthetic thylakoid system of these prokaryotic cells. Similar lattices are not seen in young cultures in the log phase of growth cultured under the same temperature and light conditions in the same medium. Factors, other than age, producing these lattices are yet to be determined.