title: Patterns of cell division, DNA base compositions, and fine structures of some radiation-resistant vegetative bacteria found in food.
abstract: Representative highly radiation-resistant Moraxella-Acinetobacter (M-A), Pseudomonas radiora, Micrococcus radiodurans, and Micrococcus radiophilus exhibited a wide variety of division systems and cell wall characteristics. However, the most resistant M-A possessed unusually thick cell walls, indicating a possible role of the cell wall in radiation resistance in the M-A. Thick septation was present in most of the bacteria studied, but was absent in P. radiora, thus excluding this as a necessity for high resistance. Reliable determination of the number of division planes of the M-A for use as a taxonomic criterion was achieved by the direct observation of dividing cells. The highly resistant M-A were found to divide in multiple planes and had base compositions of 54.0 to 57.5%, unlike typical Moraxella and/or Acinetobacter species. The taxonomic position of most highly resistant bacteria remains unclear.
mesh_terms: D001419:Bacteria / Q000166:cytology / Q000528:radiation effects* / Q000648:ultrastructure; D002455:Cell Division; D002473:Cell Wall / Q000648:ultrastructure; D003596:Cytosine / Q000032:analysis; D004269:DNA, Bacterial / Q000032:analysis; D005516:Food Microbiology; D006147:Guanine / Q000032:analysis; D013045:Species Specificity
chemical_list: D004269:DNA, Bacterial; D006147:Guanine; D003596:Cytosine