A strain of yeast which utilizes phenols was isolated from activated sludge for sewage treatment with a medium containing phenol as a sole carbon source. The yeast can oxidize p-cresol after the cells had been incubated in a medium containing phenol. An oxidation product from p-cresol, which accumulated in the reaction mixture, was isolated and crystallized. Ultraviolet, infrared, and nuclear magnetic resonance spectra, and the result of elemental analysis of the oxidation product assigned its structure to be 5-formyl-2-hydroxy-4-methyl-2, 4-pentadienoic acid. An identical compound was obtained by oxidation of 4-methylcatechol with yeast cells. These results suggest that, in the phenol-adapted yeast, an enzyme sequence is formed, by which p-cresol is oxidized to 4-methylcatechol and its benzene ring is cleaved between carbons 1 and 6.
Commercial baker's yeast cells were fractionated into small and large sized cells by repeated centrifugation, and characterization of the small cells was carried out by comparison with the original cells. The small cell preparation consists of more than 90% of small sized age 0 cells, whose length of major axis ranged from 2.5 to 4.5μ. There was no significant difference in DNA content and nuclear appearance between the small and original cell preparations. Respiratory activities were also essentially the same, but a marked difference was observed not only in RNA content but in MAR-column chromatograms. The amount of rRNA corresponding to 28S rRNA was greatly decreased in small cells and that of unidentified peak III was increased. The large cells whose length of major axis ranged from 4.5 to 6.5μ showed excellent synchrony when placed in a synthetic medium. The situation of small cells in the cell division cycle was discussed.
Fatty acid and aldehyde compositions of phospholipids from Selenomonasruminantium cells, grown under various nutritional conditions, were examined. When the cells were grown in a lactate medium or in a glucose medium supplemented with odd-numbered volatile fatty acid (valerate or heptanoate), fatty acid side chains in phospholipids were composed mainly of C15:0 and C15:1. The major fatty aldehydes in plasmalogens were C17:1 and C15:0. When cells were grown in a glucose medium supplemented with even-numbered volatile fatty acid (butyrate, caproate, or caprylate), the major fatty acids in phospholipids were C16:1 and C14:0. The main fatty aldehyde in plasmalogens was C16:1. 14C-Valerate or caproate, supplemented to the glucose medium, was incorporated into the aldehyde side chains of plasmalogens.
Cell walls were prepared from Piricularia oryzae P2. Lytic enzymes were produced when Bacillus circulans WL 12 was grown with P. oryzae cell wall as a sole source of carbon. Mode of lysis of P. oryzae cell walls was compared with the lysis of walls of Aspergillus oryzae and Neurosporacrassa. Activities of β-1→3-glucanase, chitinase, and β-1→6-glucanase were demonstrated in the culture filtrate. Modes of lysis of cell walls of P. oryzae P2 by a single and combined action of lytic enzymes were compared. Combination of β-1→3-glucanase and chitinase gave the most rapid and extensive lysis.
Two methods for detecting DNase activity on agar plates were standardized on the basis of the complex formation of DNA with either Methyl Green or Acridine Orange. Bacterial colonies which excrete DNase could be easily recognized on these plates. By these techniques, two strains of Bacillus subtilis which differed in the level of DNase activity were isolated. Nuclease activity of the two strains, SB168 and SB623, was compared under various cultural conditions. Using polyacrylamide gel electrophoresis, culture media of SB623 were found to contain at least three components of DNase activity, in contrast to SB168 culture media, which showed only one peak, presumably corresponding to the middle component of the former. Properties of these activities were studied. The nuclease-production character of SB623 could be transferred by DNA to SB168 or its derivative, giving rise to DNase-high strains. The nature of these transformants and the possible mechanisms of this transformation are discussed.
A crystalline lipase from Aspergillus niger was most severely inactivated by both Fe2+ and Fe3+ among the various metal ions tested. There were two types of inactivation depending on the extent of treatment of the enzyme with Fe ions, a reversible inhibition by a short-time contact with a lower concentration of Fe ions and irreversible inactivation by a longtime treatment with a higher concentration of Fe ions. The amount of Fe ions bound to the irreversibly inactivated lipase was determined at various inactivation degrees. It was found that the amount of Fe ions bound per mg of the inactivated enzyme protein was constant at any degree of inactivation.
The growth characteristics of a strain of yeast belonging to the genus Trichosporon have been reported. The strain of yeast grows well in mineral salt medium containing gas-oil (BP 250-350°C) as the carbon substrate at pH 4.5. The gas-oil concentrations in the medium varying from 10 to 80 per cent and different phosphate concentrations have no striking effect on the growth of the organism. Cells grown on gas-oil are separated by treatment with a mixture of polar and nonpolar solvents. Dried hydrocarbon-free cells are analyzed for crude protein, amino acids etc. The crude protein and amino acid compositions of the strain compare well with other SCP products as well as FAO reference protein.
The composition of cell wall was studied on 112 strains of coryneform bacteria. Strains named for the same genus did not always exhibit the specific composition of the cell wall. However, the tested bacteria were divided into three groups by the presence of each of DL- and LL-diaminopimelic acid (DAP), and lysine in the cell wall, and the strains of each group demonstrated a common taxonomic characteristic. From this fact, the principal amino acids, i.e., DL-DAP, LL-DAP, and lysine in the cell wall were considered to indicate the taxonomic significance of coryneform bacteria.