title: Ultrastructure of an extremely thermophilic acidophilic micro-organism.
abstract: A thermoacidophilic micro-organism, isolated from volcanic hot springs near Naples, was cultivated in vitro, and examined by electron microscopy in sections and after negative staining. The cells were almost spherical, with a diameter of about 0.7 to 1.0 mum. Their morphology was very primitive: the protoplasm was composed only of ground cytoplasm, ribosomes, and randomly distributed DNA strands. They were surrounded by a plasma membrane and by an extracellular coat about 20 nm thick which displayed a regular hexagonal pattern. Cell replication occurred by binary fission with median constriction during which a bipolar localization of nuclear material was observable. The morphology is compared with that of other known micro-organisms living in similar habitats.
mesh_terms: D001419:Bacteria / Q000254:growth & development / Q000648:ultrastructure*; D002455:Cell Division; D002462:Cell Membrane / Q000648:ultrastructure; D002473:Cell Wall / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D004269:DNA, Bacterial; D006358:Hot Temperature; D007558:Italy; D008854:Microscopy, Electron; D010772:Phosphotungstic Acid; D012270:Ribosomes / Q000648:ultrastructure; D013194:Staining and Labeling; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D010772:Phosphotungstic Acid