heliobacter pylori: the type species of genus Heliobacter; produces urease and is associated with several gastroduodenal diseases (including gastritis and gastric ulcers and duodenal ulcers and other peptic ulcers)
bacteria species: a species of bacteria
cleistothecium: closed spore-bearing structure of some fungi (especially Aspergillaceae and Erysiphaceae) from which spores are released only by decay or disintegration