Techniques for measuring methanol accumulated by resting cells of Methylosinus trichosporium in the narrow range of 70-80mM phosphate concentration have been standardized. The maximum amount of methanol, 6μmol•mg-1•hr-1, was accumulated at a cell density of 2mg•ml-1 (w/v) of cells in the early stationary phase at pH 6.5, temperature 35°C. The phosphate-dependent inhibition of methanol dehydrogenase was found to be uncompetitive and reversible. Further, 80mM phosphate inhibited methane monooxygenase and formate dehydrogenase by 16% and 20% respectively. A possible biochemical explanation of the role of phosphate inhibition is offered.
Ambrosiozyma, yeasts that produce true mycelia with transverse septa that communicate by a dolipore type septum, are compared with Hyphopichia and Hormoascus. This study includes intracellular oxidases, nitrite and nitrate reductases, guanine plus cytosine content in DNA (GC-content), cytochrome spectra (a+a3, b, c), coenzyme Q, and serological comparison by immunodiffusion and immunoelectrophoresis, with A. monospora and Hormoascus platypodis as references. The results support the division of the genus Ambrosiozyma into 2 groups based upon GC content, vitamin requirements, and serological homologies. Affinities between Hormoascusplatypodis and A. philentoma (vitamin requirements, intracellular nitrite and nitrate reductases, β-galactosidase, serological homology, cytochrome spectra, and GC content) leads to the placing of Hormoascus platypodis in synonymy with Ambrosiozyma philentoma. Ambrosiozyma ambrosiae is compared with the other Ambrosiozyma and with the non-fermentative Pichia, and Hansenula silvicola. These comparisons show that A. ambrosiae has more affinity with the other Ambrosiozyma than with Pichia or Hansenula. Hyphopichia burtonii differs from the other species in regard to vitamin requirements, coenzyme Q8, α2 band of cytochrome c and serological homologies.
The morphology of the root nodules of Pterocarpus indicus Willd ("narra") was studied by scanning and transmission electron microscopy and by light microscopy. The electron micrographs revealed that the nodule tissue cells gradually change from large to small size from the epidermal tissue to the inner core tissue. The epidermal cells have hard and thick cell walls surrounded by cork. The inner core cells have very thin cell walls (about 0.3μm thick). The inner core cells contain numerous bacteroids (1-1.5×2-4.5μm in size).
Myxobacteria were isolated in Japan from soils, decaying plant materials, and tree bark. The isolation methods we have used are the rabbit dung method, placing soil on bacterial smears, the filter paper method, and the agar medium method. Placing soil on bacterial smears was easy to manage. Addition of dealkaline lignin stimulated formation of well- differentiated fruiting bodies on agar medium. This made it possible to investigate the morphology of fruiting bodies of myxobacteria on the agar medium in the laboratory. The myxobacteria isolated and purified were found to be strains of the genera Myxococcus and Archangium. Isolates were identified as Myxococcus stipitatus, Myxococcus fulvus, Myxococcuscoralloides, and Archangium gephyra. A new species Myxococcus flavescens is proposed on the basis of morphological characteristics and production of diffusible light yellow pigment. All the tested strains gave positive reactions in catalase and urease. The DNA base composition of the myxobacteria examined ranged from 65 to 67mol% of guanine plus cytosine. The major quinone was menaquinone with 8 isoprenoid units (MK-8). The major cellular fatty acids were iso 15:0, iso 17:0, and 16:1.
Mutants of Rhizobium meliloti 41 and AK631 deficient in either glutamine synthetase I or II were characterized for growth and acetylene reduction activity. Comparison of the various mutants indicates that either GSI or GSII is competent to provide glutamine for cellular requirements with ammonia as the nitrogen source. The acetylene reduction activity of nodules induced by some GSI- or GSII- mutants was equal to the wild- type activity indicating that neither GS is required for symbiotic effectiveness and that either form is sufficient for effectiveness. No effect of purines on growth was found in the GS mutants of this strain.
Detailed taxonomic studies were applied to six ethanol-using yeasts with acid and ethanol tolerance isolated from soils and feces. It was concluded that one strain, IM-10, which has helmet-shaped ascospores, coenzyme Q- 7, and 35.6mol% of GC content of DNA, is a new species, Pichiagaleiformis. Five other anascosporogeous yeasts with coenzyme Q-7 were divided into three new species belonging to the genus Candida: one strain of C. hinoensis, three of C. soli, and one of C. solicola.
Protoplast formation and regeneration procedures were developed for lactic acid bacteria. Initial attempts to fuse the protoplasts using an electric field were unsuccessful. No fusion was observed and the protoplasts lysed when the electric field voltage was increased to 24kV/cm. However, fusion products were obtained when the protoplasts were suspended in subfusion concentrations (<20%) of polyethylene glycol (PEG) and exposed to D. C. current. Also, the PEG protected protoplasts against lysis in current fields up to 72kV/cm. The frequency of hybrid cell formation (i.e. plasmid transfer) via the electric field-induced fusion was equivalent to the plasmid transfer frequency obtained via conjugation. Chemically induced fusion resulted in a transfer frequency of an order of magnitude greater than that of conjugation.
Edited and published by : Applied Microbiology, Molecular and Cellular Biosciences Research Foundation/Center for Academic Publications Japan Produced and listed by : TERRAPUB, Center for Academic Publications Japan/Shobi Printing Co., Ltd. (-Vol.60,No12), Center for Academic Publications Japan/InternationalAcademic Printing Co., Ltd.(-Vol.54,No1)