Microbiology 

Abstract: Summary: On the basis of a comparative study of 178 strains of cyanobacteria, representative of this group of prokaryotes, revised definitions of many genera are proposed. Revisions are designed to permit the generic identification of cultures, often difficult through use of the field-based system of phycological classification. The differential characters proposed are both constant and readily determinable in cultured material. The 22 genera recognized are placed in five sections, each distinguished by a particular pattern of structure and development. Generic descriptions are accompanied by strain histories, brief accounts of strain properties, and illustrations; one or more reference strains are proposed for each genus. The collection on which this analysis was based has been deposited in the American Type Culture Collection, where strains will be listed under the generic designations proposed here.

Abstract: SUMMARY A collection of 267 strains, representing many of the principal biotypes among aerobic pseudomonads, has been subjected to detailed study, with particular emphasis on biochemical, physiological and nutritional characters. A total of 146 different organic compounds were tested for their ability to serve as sources of carbon and energy. Other characters that were studied included : production of extracellular hydrolases; nitrogen sources and growth factor requirements H-chemolithotrophy; denitrifying ability; pigment production; ability to accumulate poly-p-hydroxybutyrate as a cellular reserve material; biochemical mechanisms of aromatic ring cleavage; and nature of the aerobic electron transport system. The resultant data have revealed many hitherto unrecognized characters of taxonomic significance. As a consequence, it has become possible to recognize among the biotypes examined a limited number of species which can be readily and clearly distinguished from one another by multiple, unrelated phenotypic differences.

Abstract: SUMMARY: R factors of the compatibility class P were transferred between strains of Escherichia coli k12 and Rhizobium leguminosarum. These R factors were stable in R. leguminosarum and conferred similar levels of antibiotic resistance to those in the corresponding R+ E. coli k12 hosts, with the exception of carbenicillin resistance which was greatly reduced. Transfer between R. leguminosarum strains was by conjugation and was stimulated by conditions favouring spheroplast formation. R factor mediated recombination could not be demonstrated.

Abstract: Menaquinones were the only isoprenoid quinones found in 48 corynebacteria and actinomycete strains examined. Dihydromenaquinones having nine isoprene units were the main components isolated from Gordona, Mycobacterium, Corynebacterium bovis, Corynebacterium glutamicum and a strain labelled Nocardia farcinica, but dihydromenaquinones having eight isoprene units were characteristic of other Corynebacterium species and representatives of the 'rhodochrous' complex. Tetrahydromenaquinones having six and eight isoprene units were found in Nocardia strains and in a single strain of Micropolyspora brevicatena, which also contained mycolic acids similar in chain length to those of Nocardia. Menaquinones having nine isoprene units with from one to five double bonds hydrogenated were the main components in Actinomadura madurae, Actinomadura pelletieri, Micropolyspora faeni, Oerskovia turbata and Streptomyces strains. Actinomadura dassonvillei strains had a characteristic pattern of di-, tetra- and hexahydromenaquinones with 10 isoprene units which was slightly different from the pattern in mixtures of similar quinones from Actinomyces israelii and Actinomyces viscosus.