Differences in glucose yield of residues from among varieties of rice,wheat, and sorghum after dilute acid pretreatment

Bio-refinery processes require use of the most suitable lignocellulosic biomass for enzymatic saccharification and microbial fermentation. Glucose yield from biomass solid fractions obtained after dilute sulfuric acid (1%) pretreatment (at 180 °C) was investigated using 14, 8, and 16 varieties of rice, wheat, and sorghum, respectively. Biomass solid fractions of each crop showed similar cellulose content. However, glucose yield after enzymatic hydrolysis (cellulase loading at 6.6 filter paper unit/g-biomass) was different among the varieties of each crop, indicating genotypic differences for rice, wheat, and sorghum. Nuclear magnetic resonance method revealed that the high residual level of lignin aromatic regions decreased glucose yield from solid fraction of sorghum.     

Alterations of Hepatic Metabolism in Chronic Kidney Disease via D-box-binding Protein Aggravate the Renal Dysfunction

Chronic kidney disease (CKD) is associated with an increase in serum retinol; however, the underlying mechanisms of this disorder are poorly characterized. Here, we found that the alteration of hepatic metabolism induced the accumulation of serum retinol in 5/6 nephrectomy (5/6Nx) mice. The liver is the major organ responsible for retinol metabolism; accordingly, microarray analysis revealed that the hepatic expression of most CYP genes was changed in 5/6Nx mice. In addition, D-box-binding protein (DBP), which controls the expression of several CYP genes, was significantly decreased in these mice. Cyp3a11 and Cyp26a1, encoding key proteins in retinol metabolism, showed the greatest decrease in expression in 5/6Nx mice, a process mediated by the decreased expression of DBP. Furthermore, an increase of plasma transforming growth factor-β1 (TGF-β1) in 5/6Nx mice led to the decreased expression of the Dbp gene. Consistent with these findings, the alterations of retinol metabolism and renal dysfunction in 5/6Nx mice were ameliorated by administration of an anti-TGF-β1 antibody. We also show that the accumulation of serum retinol induced renal apoptosis in 5/6Nx mice fed a normal diet, whereas renal dysfunction was reduced in mice fed a retinol-free diet. These findings indicate that constitutive Dbp expression plays an important role in mediating hepatic dysfunction under CKD. Thus, the aggravation of renal dysfunction in patients with CKD might be prevented by a recovery of hepatic function, potentially through therapies targeting DBP and retinol.     

Optimum Culture Conditions for Production of Exfoliative Toxin by Staphylococcus hyicus

Optimum culture conditions for the production of exfoliative toxin by Staphylococcus hyicus (shET) were examined. High shET activity was obtained from the culture filtrate of HI and TY broth inoculated with S. hyicus. The pH in these two media ranged from 7 to 8.5 during bacterial culture, while the lowest pH in TS and BHI broth was less than 6. shET activity in the culture filtrate from TY broth inoculated with 10⁷ CFU of S. hyicus per ml was higher than that in TY broth inoculated with 10⁶ and 10⁸ CFU of bacteria per ml. When shET activity in the culture filtrate was measured under various shaking conditions, the culture filtrate shaken at 75 oscillations per min had the highest shET activity of the five shaking conditions. shET activity of the culture filtrate of TY broth to which protease inhibitor had been added was the same as that of TY broth without inhibitor. shET activity in a shaking culture in an Erlenmeyer flask was also the same as that in sac culture and that in shaking culture using a shaking (Sakaguchi) flask. shET activity in TY broth supplemented with 100 mM glucose was significantly lower than that in TY broth without glucose. Based on the above results, the optimum culture conditions for the production of shET were as follows: inoculation of 3 × 10⁹ CFU of S. hyicus strain P-1 into 300 ml of TY broth in a 2,000-ml Erlenmeyer flask, and incubation at 37 C with shaking at 75 oscillations per min. Then shET activity of the culture filtrate under appropriate culture conditions was measured after various incubation periods. shET activity was detected 6 hr after inoculation, reached the maximum (2⁵³ exfoliative unit/0.1 ml) at 16 hr and decreased between 20 and 48 hr. Thus, the optimum incubation period was determined to be 16 hr. Then the optimum concentration of ammonium sulfate for isolation of shET from the culture filtrate under appropriate culture conditions was examined. The greatest shET activity was obtained from the fraction salted out with 90% saturated ammonium sulfate. Thus, the optimum concentration of ammonium sulfate for the isolation of shET was determined to be 90% saturation.     

Gold-ISH: A nano-size gold particle-based phylogenetic identification compatible with NanoSIMS

The linkage of microbial phylogenetic and metabolic analyses by combining ion imaging analysis with nano-scale secondary ion mass spectrometry (NanoSIMS) has become a powerful means of exploring the metabolic functions of environmental microorganisms. Phylogenetic identification using NanoSIMS typically involves probing by horseradish peroxidase-mediated deposition of halogenated fluorescent tyramides, which permits highly sensitive detection of specific microbial cells. However, the methods require permeabilization of target microbial cells and inactivation of endogenous peroxidase activity, and the use of halogens as the target atom is limited because of heavy background signals due to the presence of halogenated minerals in soil and sediment samples. Here, we present “Gold-ISH,” a non-halogen phylogenetic probing method in which oligonucleotide probes are directly labeled with Undecagold, an ultra-small gold nanoparticle. Undecagold-labeled probes were generated using a thiol-maleimide chemical coupling reaction and they were purified by polyacrylamide gel electrophoresis. The method was optimized with a mixture of axenic ¹³C-labeled Escherichia coli and Methanococcus maripaludis cells and applied to investigate sulfate-reducing bacteria in an anaerobic sludge sample. Clear gold-derived target signals were detected in microbial cells using NanoSIMS ion imaging. It was concluded that Gold-ISH can be a useful approach for metabolic studies of naturally occurring microbial ecosystems using NanoSIMS.     

Effect of counterions on complex coacervation

In a recent paper, we developed a thermodynamic theory on the complex coacervation in the absence of low molecular ions, under the assumption that the coacervation is a condensation phenomenon of aggregates of polyanion and polycation in the aqueous solution, by obtaining the interaction potential U_S between these aggregates on the basis of Flory's method. In this paper, we have extended the theory to a more complicated phenomenon of the counterion-containing solutions. This treatment has led the interaction potential having an additional contribution to U_S resulting from an entropy increase by the counterion distribution. The phase diagram between solution (sol) and separated phase has been obtained as a function of the difference of charges between polyanion and polycation. It has been found that the presence of counterions sensitively suppresses the coacervation.     

A new method for the developmental study of the shoot apex

A method of observing and photographing an intact shoot apex prior to killing and fixing for anatomical study is deseribed. By the use of a newly devised instrument, the external shape, cell pattern in its protoderm, and the internal structure of the same shoot apex can be studied. Supported by the Grant in Aid for Scientific Research, Ministry of Education, Project No. 148017.     

Towards a next step of the research of regulatory networks in plant growth and development

Journal of Plant Research -