Five Paracoccus species, P. denitrificans, P. alcaliphilus, P. aminophilus, P. aminovorans and P. kocurii, ubiquitously contained putrescine and spermidine as major polyamines. Spermine and cadaverine were detected sporadically in some strains as a minor component. All the strains of these species produced norspermidine from diaminopropane supplemented into the medium and some strains produced two aminopropyl derivatives of cadaverine, i.e., aminopropylcadaverine and aminopentylnorspermidine. The biosynthetic ability of these unusual polyamines serves as a chemotaxonomic marker in the genus Paracoccus. P. denitrificans IFO 13301 decarboxylated ε-N-methyllysine as well as lysine but neither ε-N-acetyllysine nor δ-hydroxylysine. The orgranism formed 2-hydroxyspermidine from the supplemented 2-hydroxyputrescine as well as 2-hydroxynorspermidine from 2-hydroxydiaminopropane but not N-acetyispermidine and N-methylspermidine from N-acetylputrescine and N-methylputrescine, respectively. A halophilic species, P. halodenitrificans, which contains spermidine as the major polyamine and has no norspermidine- and aminopropylcadaverine-synthetic potential, was suggested not to be a valid member of the genus Paracoccus.
Three actinomycete strains isolated from soil, ‘Streptomyces candidus subsp. azaticus’ IFO 13803T (T=type strain) and ‘Nocardiopsisstreptosporus’ IFO 14362T were found to contain both LL- and meso-2, 6-diaminopimelic acid (A2pm) in their cell wall peptidoglycans and supposed to belong to new members of Streptomyces, yielded by unification of the genus Kitasatosporia with the genus Streptomyces. Based on the phenetic and DNA-DNA hybridization studies, these strains were considered to belong to new species of the genus Streptomyces. We propose the names Streptomyces cochleatus sp. nov. for the species represented by the soil isolate M-5T (=IFO 14768T) and S. paracochleatus sp. nov. for the soil isolate M-13T (=IFO 14769T), and S. azaticus sp. Nov. for strain IFO 13803T. ‘Nocardiopsis streptosporus’ IFO 14362T and ‘Kitasatosporiabrunnea’ IFO 14627T were included in S. phosalacinea. ‘K. melanogena’ IFO 14327T, ‘K. cystarginea’ IFO 14836T and ‘K. kifunense’ IFO 15206T were new species belonging to the genus Streptomyces. ‘K. clausa’ IFO 15240T was supposed to belong to a maduromycete. ‘K. papulosa’ and ‘K. grisea’ are synonymous, and should be reclassified as a species belonging to the cluster consisting of original Streptomyces species.
To determine the primary structure of chitosanase, which was produced by Bacillus circulans MH-K1, its amino acid sequence was analyzed. Total 183 amino acids were determined. Two kinds of primer were synthesized according to the obtained amino acid sequence, and were used for PCR amplification of chitosanase gene. A 620bp fragment was amplified, and was used for a probe for Southern hybridization of the genomic DNA which was cut by some restriction enzymes. A 5.6kb PstI fragment was isolated and introduced into pUC 19 vector. Colonies which harbored chitosanase gene containing pUC 19 were detected by colony hybridization with the probe. HindIII/HindIII fragment (1.2kb) and HindIII/SacI fragment (0.7kb) were sub-cloned and sequenced. The chitosanase gene (open reading frame is 900 by containing 259 amino acids and a signal peptide) was coded by the fragments. There was no meaningful homology to other enzymes including chitinase.
Two forms of erythrose reductave (ER-1 and ER-2) were purified from an Aureobasidium sp. mutant having high erythritol-producing activity besides the one (ER-3) reported previously. They were purified by chromatofocusing or hydrophobic chromatography after being separated from ER-3 on affinity chromatography. Physicochemical and enzymatic properties of the three forms were compared. Molecular weights were estimated to be 38, 000 for ER-1 and 37, 000 for ER-2 and ER-3 by SDS-PAGE. Isoelectric points of ER-1, ER-2, and ER-3 were 5.2, 5.0, and 4.8, respectively. All three forms behaved similarly toward pH and temperature, and showed maximum activity at pH 6.5 and 45°C. They showed essentially the same pH- and temperature-stability. D-Erythrose was the best substrate and D-glyceraldehyde, L-erythrulose, and dihydroxyacetone followed. No other aldose and ketose were reduced. There was no significant difference in the substrate specificity of the three forms. Their Km and Vmax for D-erythrose were found to be around 8mM and 0.38-0.63μmol/min/mg, respectively. Significant differences were observed in the behavior of the three forms toward metal ions such as Ag+, Fe3+, and Al3+. They showed no oxidative activity at neutral pH but showed some activity at alkaline conditions. Although the activity toward erythritol was much lower (less than 0.1%) compared with the reductive activity, the three forms showed remarkable diversity in pH-activity profile and substrate specificity.
Single and multiple mutations in the mreB, mreC, and mreD genes of Escherichia coli, which are involved in rod shape determination and the accompanied change in the cell's mecillinam resistance, caused an increase in the quantity of septum-peptidoglycan synthetase penicillin-binding protein (PBP)-3, and more general peptidoglycan synthetase PBP-1B. The mreD mutant, but not the mreB and mreC mutants, showed a decreased growth which could be suppressed by deletion of the total mreBCD-orfEF area on the chromosome. The mre mutations additionally caused a complex nature increase/decrease of several other cytoplasmic and membrane protein quantities. These results suggest that the mreB, mreC, and mreD genes are involved in a complex regulatory mechanism in the process of cell growth, division and shape determination.
The changes in the sedimentation, the surface properties, and the attachment of Pseudomonas syringae pv. atropurpurea NIAES 1309 induced by introduction of the plasmid pBPW 1::Tn7 were studied by comparing wild-type (WT) cells and cells containing the plasmid (pBPW1 cells). The cell sedimentation rate, which was markedly enhanced by the introduction of the plasmid, was investigated quantitatively by using an image analyzer. The element causing the sedimentation was assumed to exist at the cell surface. The pBPW1 cells showed a greater negative surface charge than the WT cells. Infrared spectra together with the data of the cell surface charge suggested that the pBPW1 cells contained more protein but less sugar residues at the cell surface compared with WT cells. Little difference could be found in the surface free energy, based on dispersion and polar components, between WT and pBPW1 cells. Microbial cell attachment to the surface of glass was observed continuously in a parallel plate flow system. The number of pBPW1 cells attached to the glass surface was greater than that of the WT cells: about 5 times greater after 6h from the beginning of the experiment. A factor other than the surface charge was assumed to be responsible for the cell sedimentation and/or the cell attachment to the glass surface.
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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)