The soil bacterial floras were studied in glycine- and water-percolated soils with or without PCP treatment. Many bacterial strains isolated from the percolated soils with PCP treatment died after purification, while those from the percolated soils without PCP did not die. Of the living strains, the bacterial flora in water-percolated soil with PCP treatment was composed of one specific bacterial group: gram-negative, coccoidal rod-shaped, polarly flagellated, Kovacs' oxidase positive, and neither oxidative nor fermentative in Hugh and Leifson's test. On the other hand, the bacterial flora in water-percolated soil without PCP was composed of several bacterial groups. In the glycine-percolated soil without PCP treatment one group of bacteria predominated: gramnegative, rod-shaped, polarly flagellated, Kovacs' oxidase positive, oxidative acid production from glucose in Hugh and Leifson's test, gelatin-liquefaction negative, nitrate-reduction positive, and alkaline reaction to BCP milk. However, different groups of bacteria were isolated from the glycine-percolated soil treated with PCP. Almost all of the strains isolated from the glycine-percolated soil without PCP treatment readily utilized glycine for their growth, but those isolated from the soil with PCP added utilized glycine scantily for their growth. These results indicate that PCP affects soil bacterial flora and that the bacteria responsible for glycine degradation in the glycine-percolated soil treated with PCP are different from the bacterial flora in soil without PCP, even though the apparent patterns of both glycine-degradation and the increase of bacterial population did not change in the presence of PCP.
Nitrosoguanidine-induced manganese-resistant mutants Mnr101, Mnr107, Mnr105, Mnr193, Mnr2-15 and Mnr2-7 of Azospirillum brasilense were isolated and used for associative nitrogen fixation with cheena (Panicummiliaceum L.) genotype RArM6 in acid soil (pH 5.3). Three of the Mn-resistant mutants (Mnr105, Mnr193 and Mnr101) showed crossresistance to aluminium (2.5ppm) and neomycin (15-50μg/ml) but not to streptomycin except Mnr101 and Mnr107. It is also suggested that these three mutants may be most suitable for nitrogen economy in acid soils having various pH and associated factors of acidity.
When immobilized yeast was exposed to nutrients, the resulting heat effect (dQ/dt; J sec-1) increased exponentially with a doubling time (t2) of 2.2±0.3hr. The half life (dQ/dt) under non-growing conditions with sucrose as substrate was 84hr. The kinetics of the transformation of a series of sugars were characterised. The Michaelis constant (Km) and maximal heat effect, (dQ/dt)max, were determined using two common enzyme kinetics linearization plots. The shapes of the Eadie plots for some sugars are discussed in terms of currently proposed mechanisms of their uptake.
A circular genetic map was constructed of Streptomyces peucetius var. caesius, the producer of the anti-cancer antibiotic adriamycin. For the mapping, auxotrophic mutations were used to block the synthesis of various amino acids, adenine and nicotinamide. These auxotrophic mutants were obtained by mutagenic treatment of sporulating derivatives of the original strain (IMRU 3920 hereby called H3502). Most of these derivatives utilized the purple (accumulating ε-rhodomycinone) and white mutants with a defective adriamycin biosynthetic pathway. The location of the markers on the genetic map was based on haploid recombinant selection following the experimental and analytical procedures developed with Streptomyces rimosus. Crosses were made resulting in the unambiguous placement of the markers phe-ser-met-ade-leu-phe in the anti-clockwise direction. This preliminary genetic map can be used for future mapping of the genes involved in adriamycin biosynthesis.
DNA base composition was determined in 73 strains of aerobic, gram negative, methanol-utilizing bacteria, which are divided into nine groups on the basis of chemotaxonomic characteristics and utilization of carbon compounds. Guanine plus cytosine (G+C) contents in their DNAs ranged from 50.0 to 68.8mol% G+C. Group 1 bacteria (obligate methanol -utilizing bacteria) and group 4 bacteria (Hyphomicrobium strains) showed rather wide distributions in DNA base composition, 50.0 to 56.0 mol% G+C and 59.3 to 65.6mol% G+C, respectively. In contrast, bacteria of group 2 (Protomonas strains), group 3 (Microcyclus strains), group 5 (Xanthobacter strains), group 6, group 7, and group 8 (Paracoccusdenitrificans strains) had narrow ranges in DNA base composition. Group 9 (Thiobacillus novellus) had 67.7mol% G+C. DNA-DNA homologies among the strains selected from the above-mentioned groups indicated a clear separation of the group 1 from the other groups. Further, group 1 was divided into six subgroups but not enough phenotypic characteristics were found to separate them from each other. Therefore, despite the heterogeneity of group 1 suggested by DNA base composition, DNA-DNA homology relatedness, and other chemotaxonomic characteristics, this group of bacteria are considered to be a single species from the practical point of view.
The amidase and oligopeptidase activities of peptostreptococci, peptococci and anaerobic strains of streptococci were studied. Most of the asaccharolytic species of the Genus Peptostreptococcus, which include Peptostreptococcusmicros, Peptostreptococcus magnus, Peptostreptococcusasaccharolyticus, Peptostreptococcus indolicus, and Peptostreptococcusprevotii, had very strong peptidase activities. Peptostreptococcus productus and Peptostreptococcus anaerobius, which are strongly or weakly saccharolytic species, had very weak peptidase activities. Most of the anaerobic strains of streptococci were strongly saccharolytic but their peptidase activities were divided into two groups: a high activity group and a low activity group. The former group includes Streptococcus intermedius, Streptococcus pleomorphus, Streptococcusconstellatus, and Streptococcus morbillorum. The latter group includes Streptococcus hansenii and Streptococcus parvulus. Anaerobic cocci were grouped into 7 phenons according to the analysis of their lower fatty acids as metabolic end products, and the indole and nitrate reduction tests. Several amidase and oligopeptidase tests, which are useful for differentiation at the species level in each phenon, were selected to prepare a new scheme for a rapid identification system of anaerobic cocci.
When Candida maltosa IAM12247 was grown in the presence of cycloheximide, the growth was repressed for a distinct period of time depending on the concentration of cycloheximide, then the growth recovered ("adapted"). The cell-free translation experiments using polyuridylic acid as mRNA indicated that the protein-synthesizing activity was altered in the cells adapted to resist cycloheximide. A reconstituted cell-free system was constructed consisting of ribosomes and soluble fraction (S-100), and it was concluded that ribosomal modification was induced during the cultivation of the cells in the presence of cycloheximide.
Cu2+ uptake by A. nidulans wild type was concentration dependent and followed Michaelis-Menten type kinetics with saturating concentration at 25μM. A Lineweaver-Burk plot of the data revealed an apparent Km of 16.6μM and a Vmax value of 2.5nmol mg-1 protein min-1. No characteristic pH profile was evident for Cu2+ uptake in a pH range of 4.0-9.0, although the highest uptake rate was at pH 4.0. Uptake was sensitive to protonophore FCCP, suggesting the involvement of a proton gradient. Uptake was uninhibited in the dark or in the presence of DCCD, indicating that energy generated through ATP hydrolysis may not be directly involved in the uptake process. Genetic control of the transport was suggested on the ground that mutants differed among themselves as well as from the wild type in terms of Km and Vmax values.
A bacterium, isolated from human saliva, produced carbon monoxide (CO) when cultured in nutrient broth containing hemin or hemoglobin. The production of CO was detected by gas chromatography, and confirmed by gas chromatography-mass spectrometry and spectrophotometry which revealed an absorption spectrum of CO-hemoglobin. The isolated bacterium was identified as a strain of Proteus vulgaris. Survey of 4 IFO strains of P. vulgaris, 1 IFO strain of P. mirabilis and 2 IFO strains of Morganella morganii (received as P. morganii) showed that all the 7 strains had the ability to produce CO. They produced detectable amounts of CO when cultured in a glucose-peptone medium or in the nutrient broth without the addition of heme compound, and the CO production was distinctly enhanced by the addition of hemin. Morganellamorganii IFO 3168, the most active CO producer among the strains tested, produced about 2μmol of CO in the absence of hemin and 6μmol of CO in the presence of 3μmol of hemin. The result suggests that CO production by the Morganella strain is different from the CO production by mammalian tissues where 1mol of protoheme is degraded to 1mol each of CO and biliverdin.
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)