A new Lactobacillus isolated from dried cow dung using a medium containing xylose as a sole carbon source is described. The strains of the species are heterofermentative, contain meso-diaminopimelic acid in cell wall peptidoglycan, and actively ferment pentoses more than hexoses. Heterofermentative lactobacilli which contain meso-diaminopimelic acid in cell wall peptidoglycan have not been reported so far and, therefore, the isolate should be classified into a new species and was named Lactobacillusvaccinostercus KOZAKI and OKADA sp. nov.
When DNA from ρ11c3, a clear mutant of temperate phage ρ11, was digested with the restriction endonuclease BamHI and the products were analyzed by agarose gel electrophoresis, there appeared eight distinct fragments which could be designated as BamHI A-H in the order of decreasing size. To study the order of their arrangement on the ρ11c3 DNA, many plaque-forming deletion mutants were isolated from ρ11c3 and compared with ρ11c3 on BamHI cleavage pattern in agarose gels. The arrangement was tentatively determined as D-G-E-C-A-(F-H)-B. The thymidylate synthetase gene in the ρ11 genome was found to reside on the fragment A. It was found, moreover, from studies of ρ11c3 deletion mutant DNAs that deletions in the D-G-E region and the C region gave no lethal effect on the phage.
Certain temperature-sensitive sporulation mutants were used to study the sporulation process of Bacillus subtilis. Among the isolated mutants, four, spo-ts 2A, 4A, 7A, and 15A, were found to produce spores at 43° provided the medium was enriched with glutamate or aspartate (20mM) at a time before the initiation of sporulation. This effect appeared to be mutation-specific; sporulation of other spo-ts mutants was not cured by glutamate. Moreover, genetic study has indicated that 2A, 4A, and 7A mutations are clustered in the region between the purA and the novA.
When Pseudomonas sp. strain 351 (P. 351), a psychrotroph, and Pseudomonasaeruginosa and Bacillus subtilis, mesophiles, were exposed to 0°, viability of P. 351 was little changed during the chilling for 16 days, whereas that of P. aeruginosa and B. subtilis was reduced to about 40% after 2 and 4 days of chilling, and was lost completely after 16 and 8 days, respectively. Protein-synthesizing activity of P. 351 at 0°, 10°, and 20° was little changed or stimulated by chilling for 4 days, whereas that of P. aeruginosa was markedly depressed by the same treatment. However, RNA synthesis was activated by chilling for 4 days both in P. 351 and P. aeruginosa. From these results, cold-sensitivity of the protein-synthesizing system in P. aeruginosa seems to be closely related with diminution of its viability in low temperatures.
A linear plasmid-like DNA was isolated by Agarose gel electrophoresis from a lysate of Streptomyces sp. 7434-AN4 which produces lankacidin group antibiotics. The DNA (pSLA2) with a molecular weight of 11.2×106 was cleaved into five and three fragments, respectively, with XmaI and BamNI on the definite sites from the end, but not digested by EcoRI and HindIII. Upon treatment of the strain with ethidium bromide, variants were obtained which have lost the ability to produce the antibiotics. These variants were found to have lost pSLA2. These results suggest that the linear plasmid-like DNA is involved in the production of lankacidin group antibiotics.
An appreciable amount of nitrogen-fixing (acetylene-reducing) activity was observed in the excised roots of graminaceous weed, Eragrostisferruginea. The highest activity obtained at 5% oxygen concentration was 26.8nmol acetylene reduced/g/hr. From the excised root, an aerobic bacterial strain with rapid growth on nitrogen-deficient medium and high acetylene-reducing activity was obtained. The isolate, termed ER201, was Gram-negative nonmotile rod and resembled Azotobacter, although its taxonomic position is uncertain. Glucose, sucrose, ethanol, acetate, lactate, malate, pyruvate, and succinate supported its N2-dependent growth, while lactose, rhamnose, starch, xylose, glycerol, citrate, and p-hydroxybenzoate did not. At the expense of 1g of glucose, 7.3 to 7.5mg of nitrogen was fixed. Specific activity of the isolate for acetylene reduction was 37.7nmol acetylene reduced per mg cell protein per min under 10.6% oxygen concentration. The isolate failed to grow in nitrogen-deficient media with initial pH below 6.6, while its growth was abundant at pH 6.8 or higher.