The dextransucrase produced by orange-colored Streptococcus bovis No. 148 isolated from bovine rumen was investigated. The enzyme was produced in both sucrose and glucose media. The enzyme prepared from the glucose medium was specifically adsorbed on various Sephadex gels. But that from the sucrose medium was not adsorbed. When the enzyme from the glucose medium was incubated with a certain dextran, it was no longer adsorbed on Sephadex. There was no saccharide in the enzyme produced in glucose medium.
Whole-cell pastes of eight Candida species and their suggested teleomorph counterparts in the genera Pichia and Issatchenkia analyzed were spectrophotometrically. All of these yeasts, included in the two very closely related groups "krusei" and "norvegensis, " showed strong similarities in their low-temperature cytochrome absorption spectra, especially in two typical peaks, generally at 597-597.5nm and 605-606.5nm or in some cases at 593.5-594.5nm and 601.5-602nm, in the spectral region of the α maximum absorption of cytochrome aa3. In addition, the two species of each assumed pair of perfect and imperfect yeasts, I. orientalis/C. krusei, I. occidentalis/C. sorbosa, P. fermentans/C. lambica, P. nakasei/C. citrea or P. norvegensis/C. norvegensis were indistinguishable. Cytochrome spectra also indicated that I. terricola may no longer be considered a teleomorph of C. diversa.
The present investigations were undertaken to determine the effect of many physical and chemical factors on the silica solubilizing activity of a species of Bacillus. The bacteria, previously reported to release silica from magnesite ore, was found to do so at an optimum temperature of 37°C. Changing the temperature inhibited the silica release. An optimum shaking condition of 50-100 r.p.m. was suitable for maximum silica release. The best results were obtained with a medium containing ammonium sulfate, yeast extract among the nitrogen sources, disodium hydrogen phosphate and potassium dihydrogen phosphate as phosphate sources, magnesium sulfate and manganese sulfate as divalent cations. An incubation period of 8 days was favourable for maximum silica release by the microorganism.
In the infertile sandy soils of northeast Thailand, field experiments were conducted to evaluate the effects on rates of biological nitrogen fixation (BNF) of inoculating soybeans with selected strains of Bradyrhizobiumjaponicum and adding herbicides. Inoculating soybean seeds with effective B. japonicum strains increased the acetylene reduction by nodulated root systems, and increased the nodule numbers and dry weights associated with soybean roots. The amounts of N2 fixed, as measured by N-15 isotope dilution methods, were also increased by adding the B. japonicum. Inoculation of soybeans with a nif- strain of B. japonicum resulted in increased nodule weights and numbers, but did not increase the acetylene reduction rates or the amounts of N2 fixed. There was a significant strain- cultivar interaction. Application of metolachlor, alachlor, fluazifop butyl or sethoxydim did not reduce the levels of N2 fixed by B. japonicum in association with soybeans, but paraquat did significantly reduce the N2 fixed by the inoculated plants.
A chitosanase was concentrated from the culture broth of Bacilluscirculans MH-K1 and was purified to homogeneity by CM-cellulose and gel permeation chromatography. The enzyme has a molecular weight of about 30, 000, its Km is 0.63mg chitosan/ml and its pI is 9.2. The maximum velocity of chitosan degradation by the enzyme was obtained at 50°C when pH was maintained at 6.5. The enzyme was stable within the range of 0-40°C and pH 4.0-9.0. p-Chloromercuribenzoate and the metal ions of Cu2+ Hg2+, Ni2+, and Zn2+ inhibited the enzyme activity. The enzyme degraded chitosan, glycolchitosan and CM-chitosan, but β-1, 4-glucans such as chitin or its derivatives and CM-cellulose were not susceptible to the enzyme. The degree of deacetylation of chitosan significantly affected its susceptibility to the enzyme action. The most susceptible substrate was 80% deacetylated chitosan, and the substrates with less than 40% deacetylation were not affected by the enzyme. It is suggested that the presence of N-acetylglucosamine residues in the molecule of chitosan play an important role in the recognition of the substrate by the enzyme. The enzyme showed an endo-splitting type of activity, and the end product of chitosan degradation contained a mixture of the dimer and trimer of glucosamine. The smallest of the substrates was a tetramer of glucosamine.
The morphological, physiological, and biochemical characteristics, and the chemotaxonomic data of Rhodosporidium infirmominiatum strains indicate a close relationship to the strains of the genus Cystofilobasidium in the Filobasidiaceae. Therefore, Rhodosporidium infirmominiatum is eclassified in the chemotaxonomically defined genus Cystofilobasidium, as Cystofilobasidium infirmominiatum (Fell, Hunter et Tallman) Hamamoto, Sugiyama et Komagata comb. nov. which includes its anamorph taxa. Interrelations among Rhodosporidium, Rhodotorula, Cystofilobasidium, Mrakia, and Leucosporidium are discussed.
Rhodotorula hasegawae IFO 1058 (holotype) with the major ubiquinone system, Q-10(H2), produces the teleomorph from a single cell without mating. Its apparent life cycle is presented here. It is concluded that this fungus is related to the filobasidiaceous yeasts in the Basidiomycotina since it lacks probasidia (teliospores) and phragmobasidia bearing sessile basidiospores that are not forcibly discharged. Therefore, R. hasegawae is transferred to a new teleomorph-genus Erythrobasidium placed in the family Filobasidiaceae, as Erythrobasidium hasegawae (Yamada et Komagata) Hamamoto, Sugiyama et Komagata, comb. nov.
A taxonomic study below the generic or at the specific level was made of electrophoretic patterns of seven enzymes in 18 strains of the Q9-equipped Sporobolomyces and Bensingtonia species. The seven enzymes were glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase, malate dehydrogenase, hexokinase, phosphoglucomutase, and fumarase. Seven species, S. intermedius, S. miscanthi, S. subroseus, S. yamatoanus, S. naganoensis, S. yuccicola, and S. phylladus, constituted clusters separate from each other (s=0 or 14%). The two strains of S. miscanthi showing identical electrophoretic enzyme patterns (s=100%) were linked to Sporobolomyces species NZ-3 with a similarity value of 29%. Within the five strains of S. yamatoanus examined, the type strain had a similarity value of 86% with one other strain. The remaining three strains whose similarity values were calculated as 100% and 57% were linked to the two strains including the type strain with a similarity value of 43%. The three strains of S. phylladus had identical electrophoretic enzyme patterns (s=100%). Sporobolomyces species NZ-24 had a separate cluster (s=0%). Sporobolomyces weijmanii was synonymous with S. intermedius (s=100%). Bensingtonia ciliata constituted its own cluster (s=0%). These data are discussed from the taxonomic point of view.