A new obligately halophilic methanogenic bacterium, strain IY-1, was isolated from a salt water pond near San Francisco Bay. The bacterial cells are pleomorphic cocci, 0.3-1.5μm in diameter and require a minimum of 10% salt (1.8M NaCl) for growth. Optimum growth occurs at 17.5% salt (3.0M NaCl). Methanogenic substrates included methylamines and methanol, but not formate, H2/CO2, or acetate. Acetate and rumen fluid were required for cell growth. Growth occurred throughout the temperature range 5 to 45°C with an optimum at 35°C. The pH optimum for growth was 6.8 and cell growth occurred throughout the pH range 5.8 to 7.6. Growth in complex medium had a doubling time of 9hr at 37°C. The cells were not easily ruptured by mechanical means and were not sensitive to penicillin G, cycloserine, or rifampicin. Bacterial colonies formed on solid medium were white and circular to oval in shape, with irregular margins. Electron micrographs of ultrathin sections revealed homogeneous granular ribosome-like particles and a thin cell wall, but the membrane could not be observed by the standard Kellenberger's fixation method. The DNA base composition of the isolate was 43.2mol% guanine plus cytosine. We propose Halomethanococcus gen. nov. as the genus and Halomethanococcus doii sp. nov. as the type species for this novel bacterium. Strain IY-1 is the type strain (ATCC 43619).
Uptake of NH4+ by Anabaena cells in the dark at the physiological pH range of 6 to 8 occurred only under aerobic conditions and was accompanied by an efflux of H+ ions. Uptake of NH4+ also stimulated a K+ net efflux in the dark but not in the light. Uptake of NH4+ and efflux of H+ and K+ were strongly inhibited by DCCD, an inhibitor of H+-translocating ATPase. A protonophore CCCP, known to inhibit NH4+ uptake, greatly stimulated K+ efflux. It is concluded that the uptake of NH4+ is an energy-dependent process and may be coupled to the H+ efflux. The K+ efflux may be secondarily stimulated by the NH4+ uptake.
A facultative nitrogen-fixing bacterium was isolated from the roots of eelgrass (Zostera marina) growing in Aburatsubo Inlet, Kanagawa Prefecture, Japan. The isolate grew anaerobically using molecular nitrogen as the sole nitrogen source. However, NH4Cl could also serve as a nitrogen source, under either aerobic or anaerobic conditions. The nitrogenase activity of the isolate was very weak under aerobic conditions, but was easily detected within a few hours under anaerobic conditions. It was enhanced by some sugars and was Na+-dependent. Morphological, physiological, and biochemical characteristics, as well as the guanine-plus- cytosine content of its DNA (45.4±0.3mol%) placed the isolate in the genus Vibrio of the family Vibrionaceae. The isolate was not identical to two previously described nitrogen-fixing species of the genus Vibrio, Vibrio diazotrophicus and Vibrio natriegens.
This study was conducted with algae living in a sugar refinery wastewater environment. Algae common in organic-polluted environments such as Chlorella sp., and Scenedesmus quadricauda were found, along with some other species not so common in this type of environment. Most species were isolated and the resulting axenic cultures were used to establish their heterotrophic potential with different organic compounds found in this type of habitat. Chlorella sp., showed the best adaptive pattern since it had adapted its glucose transport system to operate by facilitated diffusion. It exhibited a higher affinity than other systems of glucose facilitated diffusion and also a higher Vm, which was obtained at about the sugar concentration occurring in its natural habitat. Moreover, Chlorella sp., could increase its glucose uptake rate under some specific conditions of growth.
Seventeen strains of ballistosporous yeasts isolated from various plant materials in Japan and Canada were found to represent an undescribed species. The ballistospores of these yeasts are variously shaped. Some of them are turbinate, ampulliform, or chestnut-shaped with a hilum on the deflected position, while others are polygonal such as trigonal, tetragonal, pentagonal, rhomboid, etc. The biochemical and physiological characteristics of these yeasts place them in the genus Bullera. The electrophoretic pattern of enzymes differs from strain to strain, which suggests that these yeasts constitute several different species. However, no distinct groups were distinguished based on enzyme patterns or other taxonomic characteristics. We group these yeasts in a single species from the practical point of view. The name Bullera variabilis Nakase et Suzuki is given to this species.
The amylase gene of a mutant of Bacillus licheniformis was cloned in a plasmid pBR322 by a shotgun method and transferred into Escherichiacoli HB101. The transformants produced amylase in the medium. A restriction map of the plasmid carrying amylase gene (pNTK1) was constructed and the smaller plasmids pNTK2 and pNTK3 were made. Ninety-three percent of the amylase activity in the E. coli carrying pNTK3 was found in the periplasmic region. A shuttle vector (pSNK1) was constructed from pNTK3 and pUB110 and it is maintained in both E. coli and Bacillus. The amylase productivity of various Bacillus cells carrying pSNK1 were found to be different from strain to strain. The causes of these differences are discussed.
A taxonomic study below the generic or at the specific level was made of the electrophoretic patterns of five enzymes in fourteen strains of Schizosaccharomyces, Octosporomyces, and Hasegawaea species. The five enzymes were glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, hexokinase, phosphoglucomutase, and fumarase. All of the six strains of Schizosaccharomyces pombe examined were linked to each other with a similarity value of 40% or more. The type strain of Schizosaccharomyces malidevorans was closely related to that of S. pombe with a similarity value of 60%. The similarity values of three strains of Octosporomyces octosporus were 80% or more. All of the three strains of Hasegawaea japonica var. japonica examined had a uniform electrophoretic enzyme pattern. The similarity value between the strains of H. japonica var. japonica and H. japonica var. versatilis was 60%. The three species, S. pombe, O. octosporus, and H. japonica had quite different electrophoretic enzyme patterns. Their similarity values were all 0%. The Co-Q systems of the strains were reinvestigated. These data are discussed from the taxonomic point of view.
DNA-DNA hybridization was carried out to clarify the taxonomic relationship among the radiation-resistant Acinetobacter and other Acinetobacter strains. Twenty-six of the thirty-one strains examined were divided on the basis of DNA homology into five separate groups, but the other five strains were not allocated to any groups. Group 1 was composed of seven named strains from culture collections and four isolates together with the type strain of Acinetobacter calcoaceticus. Group 2 consisted of two named strains with the type strain of Acinetobacter lwoffii. Groups 3 and 4 consisted respectively of three named strains and one isolate. And group 5 consisted of the radiation-resistant strain FO-1 isolated from a cotton sample and two strains (G82012 and G82076) isolated from soil samples. The DNA of strain FO-1 showed less than 44% DNA homologies to the DNAs of the authentic Acinetobacter strains. On the other hand, the DNAs of strains G82012 and G82076 from soil showed respectively 92.0 and 91.1% DNA homologies to the DNA of strain FO-1. These two strains from soil were also resistant to gamma-rays. Therefore, it was concluded that these three radiation-resistant Acinetobacter strains were taxonomically separate from the other Acinetobacter species.