The growth yield of orange-colored Streptococcus bovis No. 148 isolated from bovine rumen was investigated. The high growth yield of S. bovis occurred in the presence of CO2 under batch culture conditions, and the maximum value for YATP (the gram dry weight of organism produced per mol of ATP) was about 18. The growth yield was decreased by the addition of NaHCO3 or Na2CO3 which are commonly used as neutralizing agents for the culture of ordinary rumen bacteria. The growth-promoting effect of CO2 could be partially replaced by some unsaturated fatty acids and oleate-containing compounds. It is suggested that lipid synthesis from CO2 may be a rate-limiting step in the growth of S. bovis.
The biological properties of a Bacillus subtilis defective phage PBSH and it's complementary DNA strands were examined. The biological properties examined were the killing action against sensitive strains and the transforming activity of the single-stranded DNA. Purified phage particles showed the killing action against the sensitive B. subtilis strains. DNAs isolated from phage particles were separated into their complementary strands on a methylated albumin kieselguhl (MAK) column. Transforming activity for various markers in the light (L) and heavy (H) fractions were determined after separation of strands of denatured phage DNA. The ratio between purA, a marker close to the replication origin, and metB, a marker close to the replication terminus, was 30-50 for both the (L) and (H) fractions. The transformation activity of both fractions was reduced to less than 7% compared to that of native DNA. Therefore, the enrichment of purA marker in both strands was maintained after separation of strands.
Temperature-dependency of poly(U)-directed polyphenylalanine synthesis was examined with different cell-free systems of Vibrio sp. strain ABE-1, a psychrophile, and Pseudomonas aeruginosa, a mesophile. In S-30 fractions, the activity of V. ABE-1 was higher than that of P. aeruginosa at and below 25°, but the activity of the former decreased rapidly above 25° and was completely lost at 40°. In ribosome-supernatant systems, V. ABE-1 ribosomes, especially 50S subunits, served a cold-stabilizing function, but V. ABE-1 supernatant was remarkably thermolabile, which was probably attributable to thermo-inactivation of phenylalanyl-tRNA synthetase present in the supernatant. V. ABE-1 ribosomes had no activation factor able to be released by washing with 1M NH4Cl.
Escherichia coli cells were cultured at 20° in variously diluted peptoneyeast extract media, of which the highest concentrations of the components were 10g and 5g, respectively, in 1l. The average size of the log-phase cells grown in these media gave a minimum value at the dilution level of one-hundredth. ATP and protein contents per cell also gave minimum values in cells grown in media of a similar dilution level. Whereas, the adenylate energy charge remained unchanged at about 0.9 in cells grown in a wide range of the dilution. Growth rate and other physiological characteristics also changed with the dilution of culture medium. The pattern of change in growth rate as a function of medium concentration was definitely different from those in terms of mass-increase rate, RNA content per cell and rate of protein synthesis; the latter three characteristics gave the same patterns. The difference in the regulation of growth rate and cell mass in relation to medium concentration is discussed.
A new bacteriophage φNR2 isolated with Bacillus amyloliquefaciens 203 as host is adsorbed by cells of B. subtilis Marburg, however, the infection is abortive. This behavior seems to be analogous to that of phage SP10. Therefore, biological and physico-chemical properties of phage φNR2 were studied in comparison with those of phage SP10C. The most critical differences between the two phages are the antigenic specificities and nonhomology of DNA shown by hybridization experiments. In addition, comparisons of melting temperature, buoyant density and chemically determined base composition indicate that phage φNR2 DNA does not contain unusual bases, while phage SP10 DNA is known to contain abnormal bases replacing thymine. These data show the unrelatedness of phage φNR2 and phage SP10.
A mutant strain PS9, permissive to infection of phages SP10 and φNR2, was derived from a nonpermissive Marburg strain of Bacillus subtilis. When treated with mitomycin C or ultraviolet irradiation, PS9 cells lysed to produce defective phage PBSX as did the nonpermissive cells. Thus it was suggested that the nonpermissiveness might be independent of the repression system of the defective phage PBSX. As another approach to elucidate the mechanism of nonpermissiveness, DNA and RNA syntheses were analyzed in both permissive and nonpermissive cells infected with phage φNR2. By molecular hybridization with phage DNA, it was found that, in the nonpermissive cells, φNR2 DNA did not replicate but phage-directed RNA was partially synthesized. The RNA synthesized in the nonpermissive B. subtilis Marburg appeared to lack late messenger RNA compared to RNA synthesized in the permissive cells.