Salinity Decreases Nitrite Reductase Gene Diversity in Denitrifying Bacteria of Wastewater Treatment Systems

Investigation of the diversity of nirK and nirS in denitrifying bacteria revealed that salinity decreased the diversity in a nitrate-containing saline wastewater treatment system. The predominant nirS clone was related to nirS derived from marine bacteria, and the predominant nirK clone was related to nirK of the genus Alcaligenes.     

Studies on Phyto-peroxidase

Peroxidase c was isolated and purified from Japanese-radish roots by means of a chromatographic technique with carboxymethyl cellulose. Two or more components exhibiting the absorption spectrum of peroxidase c were separated chromatographically, and the most basic component was crystallized from ammonium sulphate solution. The Reinheit Zahl and the purpurogallin number of the crystalline preparation were found to be 3.55 and 1100 respectively. The absorption maxima were found at 420 and 540 mμ, for the oxidized form and at 425 and 560 mμ for the reduced form. The crystalline preparation contained 1.57% protohematin as the prosthetic group, and then the minimum molecular weight of peroxidase c was found to be 41500.     

Intracellular accumulation of trehalose and glycogen in an extreme oligotroph,Rhodococcus erythropolis N9T-4

An extreme oligotroph, Rhodococcus erythropolis N9T-4, showed intracellular accumulation of trehalose and glycogen under oligotrophic conditions. No trehalose accumulation was observed in cells grown on the rich medium. Deletion of the polyphosphate kinase genes enhanced the trehalose accumulation and decreases the intracellular glycogen contents, suggesting an oligotrophic relationship between among the metabolic pathways of trehalose, glycogen, and inorganic polyphosphate biosyntheses.     

Biotic and Abiotic Factors Controlling Respiration Rates of Above- and Belowground Woody Debris of Fagus crenata and Quercus crispula in Japan

As a large, long-term pool and source of carbon and nutrients, woody litter is an important component of forest ecosystems. The objective of this study was to estimate the effect of the factors that regulate the rate of decomposition of coarse and fine woody debris (CFWD) of dominant tree species in a cool-temperate forest in Japan. Respiration rates of dead stems, branches, and coarse and fine roots of Fagus crenata and Quercus crispula felled 4 years prior obtained in situ ranged from 20.9 to 500.1 mg CO₂ [kg dry wood]^–1 h^–1 in a one-time measurement in summer. Respiration rate had a significant negative relationship with diameter; in particular, that of a sample of Q. crispula with a diameter of >15 cm and substantial heartwood was low. It also had a significant positive relationship with moisture content. The explanatory variables diameter, [N], wood density, and moisture content were interrelated. The most parsimonious path model showed 14 significant correlations among 8 factors and respiration. Diameter and [C] had large negative direct effects on CFWD respiration rate, and moisture content and species had medium positive direct effects. [N] and temperature did not have direct or indirect effects, and position and wood density had indirect effects. The model revealed some interrelationships between controlling factors. We discussed the influence of the direct effects of explanatory variables and the influence especially of species and position. We speculate that the small R ² value of the most parsimonious model was probably due to the omission of microbial biomass and activity. These direct and indirect effects and interrelationships between explanatory variables could be used to develop a process-based CFWD decomposition model.     

Herpes Simplex Virus 1 VP22 Inhibits AIM2-Dependent Inflammasome Activation to Enable Efficient Viral Replication

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High production of a class III lantipeptide AmfS in Streptomyces griseus

AmfS, a class III lantipeptide serves as a morphogen in Streptomyces griseus. Here, we constructed a high production system of AmfS in S. griseus. We isolated S. griseus Grd1 strain defective in glucose repression of aerial mycelium formation and found it suitable for the overproduction of AmfS. Two expression vectors carrying the strong and constitutive ermE2 promoter were constructed using a multicopy number plasmid, pIJ702. The use of the Grd1 strain combined with the expression vectors enabled high production of AmfS by S. griseus into its culture broth. The expression system was also effective for the generation of abundant AmfS derived from Streptomyces avermitilis. In addition, site-directed mutagenesis revealed the amino acid residues essential for the morphogen activity of AmfS. These results indicate that the constructed system enables efficient production of class III lantipeptides by Streptomyces.     

Biochemical characterization of thermostable β-1,4-mannanase belonging to the glycoside hydrolase family 134 from Aspergillus oryzae

Applied Microbiology and Biotechnology - A β-1,4-mannanase, termed AoMan134A, that belongs to the GH 134 family was identified in the filamentous fungus Aspergillus oryzae. Recombinant...     

Dynamics and local ordering of spin-labeled prion protein: an ESR simulation study of a highly PH-sensitive site

Valine 160 on beta-sheet-2 (S2) of mouse prion (moPrPC) has been previously identified as the most highly pH-sensitive site on moPrPC by ESR spectroscopy using site-directed spin labeling (SDSL) technique. However, no further theoretical analysis to reveal the molecular dynamics reported on the experimental ESR spectra is available. The X-band ESR spectra of R1 nitroxide spin label at V160 and four other sites are carefully analyzed over large pH and temperature ranges using a spectral simulation method based upon stochastic Liouville equation (SLE). The results clearly reveal the dynamics and ordering of the local environment of V160R1 showing that (i) molecular mobility of V160R1 on S2 gradually increases with a decrease of pH from 7.5 to 4.5; (ii) two distinctly different spectral components are simultaneously present in all spectra of V160R1 studied. The spectral components are, respectively, denoted as immobile (Im), characterized by lower molecular mobility and higher ordering, and mobile (Mb) component of high mobility and low ordering. The population ratio (Im/Mb) increases with increasing pH, while Im remains dominant in all V160R1 spectra. It suggests a more mobile and disordered dynamic molecular structure for mouse PrPC, which is very likely correlated with increased beta-sheet content at low pH, as the environment changes from neutral to acidic pH. Together with the results of the SLE-based analyses on the spectra of other sites that appear pH-insensitive, we suggest that the simultaneous presence of the spectral components for V160R1 is strongly correlated with the coexistence of multiple protein conformations in local structure of PrPC over the varied pH range. It demonstrates that the combined approach of the SDSL technique and the SLE-based analysis leads to a powerful method for unraveling the complexity of protein dynamics.     

Zebrafish β-adrenergic receptor mRNA expression and control of pigmentation

Beta adrenergic receptors (β-ARs) are members of the G-protein-coupled receptor superfamily and mediate various physiological processes in many species. The expression patterns and functions of β-ARs in zebrafish are, however, largely unknown. We have identified zebrafish β-AR orthologs, which we have designated as adrb1, adrb2a, adrb2b, adrb3a and adrb3b. adrb1 was found to be expressed in the heart and brain. Expression of adrb2a predominated in the brain and skin, whereas adrb2b was found to be highly expressed in muscle, pancreas and liver. Both adrb3a and adrb3b were exclusively expressed in blood. Knock-down of these β-ARs by morpholino oligonucleotides revealed a functional importance of adrb2a in pigmentation. Expression of atp5a1 and atp5b, genes that encode subunits of F1F0-ATPase, which is known to be involved in pigmentation, was significantly increased by knock-down of adrb2a. Our data suggest that adrb2a may regulate pigmentation, partly by modulating F1F0-ATPase.