Pasteuriaceae

The Pasteuriaceae are a family of nonmotile Gram-positive bacteria. They are moderately to strongly resistant to heat. Species in this family produce a septate mycelium with one refractile endospore. The mycelium grows bigger on one end to form sporangia and sometimes endospores. The size of the endospores is different for each species of the genus "Pasteuria". Species of the family of Pastueriaceae are endoparasitic in plant, soil, and freshwater invertebrates.
Parasitism.
Bacteria of the Pasteuriaceae family are endoparasitic within nematodes or cladoceran hosts. After the infection, the host gets castrated by the parasite and shows gigantism. The infection pathway is not fully discovered yet. The core of the endospores is covered by glycoproteins that are presumed to be involved in the attachment of the endospores to the invertebrates host.