A considerable amount of heat was produced when a suspension of yeast was added to a suspending medium in the absence of an exogenous energy source. The amount of heat produced was proportional to the cell concentration and accompanied by oxygen consumption, suggesting that the exothermic reaction may be due to the endogenous metabolism of cells. The patterns of heat production varied with the physiological state of cells, which were influenced by several factors including culture conditions, methods of storage, starvation, temperature and the suspending medium used for calorimetric measurements.
When homothallic cells of Schizosaccharomyces pombe were plated on agar sporulation medium, a few residual divisions were usually observed before induction of conjugation and sporulation. Four cells resulting from the last two residual divisions were usually lined; the "four-lined-cell" formed. Each four-lined-cell contained only one zygote by sistercell-or non-sistercell-copulation, and never two zygotes by two sistercell-copulations. Some of the remaining non-zygotic sistercells divided once again and resulted in the new formation of the four-lined-cell which contained only one zygote. The remaining non-zygotic cell of the four-lined-cell could conjugate with that of another four-lined-cell. These results suggest that the four-lined-cell is to be regarded as one unit with respect to zygote formation.
Viable deletion mutants of actinophage R4 have been isolated using a pyrophosphate treatment. One of the deletion mutants, named R4Δ2, was shown to have a deletion of 0.98 megadaltons. A successful cloning of foreign DNA previously cleaved by SmaI endonuclease demonstrated that a unique PvuII site of R4Δ2 DNA was located in a dispensable region. The usefulness of R4 deletion mutants as cloning vectors in Streptomycesis discussed.
The cellular fatty acid composition was determined for 53 strains of acetic acid bacteria by gas-liquid chromatography. The representatives of the genera Gluconobacter and Acetobacter contained the straight-chain unsaturated acid of C18:1 as a major constituent. Other acids were the straight-chain saturated acids of C16:0 and C18:0 and unidentified acids. The genus Acetobacter was discriminated from the genus Gluconobacter by the former having a detectable amount of the straight-chain saturated acid of C14:0 under experimental conditions. In contrast, the polarly flagellated intermediate strains represented the cellular fatty acid profiles composed of the iso-branched chain acid of C15:0. These results are discussed in connection with the ubiquinone system. The cellular fatty acid composition is proposed here as a novel criterion for characterizing acetic acid bacteria, especially the polarly flagellated intermediate, or A. aurantius.