Stimulation of Methionine Sulfoxide Reduction and Ethylene Production by Isoprothiolane in Relation to Its Activity against Non-parasitic Damping-off (MURENAE Disease) of Rice Seedlings

A rice blast controlling agent, isoprothiolane (diisopropyl 1,3-dithiolan-2-ylidenemalonate), stimulated the reduction of methionine sulfoxide to methionine by the rice plant. In the presence of isoprothiolane, the methionine/(methionine + its sulfoxide) ratio was increased to 129~208% of the control. The ethylene production by the plant was also enhanced by isoprothiolane, probably because methionine is an important precursor of ethylene. The non-parasitic damping-off caused by chilling stress on rice seedlings was effectively prevented with the application of isoprothiolane as well as ethephon, which easily decomposes to ethylene and acids. Therefore, the ethylene level modified by isoprothiolane and ethephon can contribute to their protective activity against the non-parasitic damping-off of rice seedlings. Indeed, a close relationship between the ethylene level and the protective activity against damping-off was obtained with isoprothiolane, but not with ethephon. Endogenous ethylene seems to be more effective in controlling the damping-off than exogenous ethylene from ethephon.     

Transmission ratio distortion of molecular markers in a doubled haploid population originated from a natural hybrid between Osmunda japonica and O. lancea

In ferns, intra-gametophytic selfing occurs as a mode of reproduction where two gametes from the same gametophyte form a completely homozygous sporophyte. Intra-gametophytic selfing is considered to be prevented by lethal or deleterious recessive genes in several diploid species. In order to investigate the modes and tempo of selection acting different developmental stages, doubled haploids obtained from intra-gametophytic selfing within isolated gametophytes of a putative F1 hybrid between Osmunda japonica and O. lancea were analyzed with EST_derived molecular markers, and the distribution pattern of transmission ratio distortion (TRD) along linkage map was clarified. As the results, the markers with skewness were clustered in two linkage groups. For the two highly distorted regions, gametophytes and F2 population were also examined. The markers skewed towards O. japonica on a linkage group (LG_2) showed skewness also in gametophytes, and the TRD was generated in the process of spore formation or growth of gametophytes. Also, selection appeared to be operating in the gametophytic stage. The markers on other linkage group (LG_11) showed highest skewness towards O. lancea in doubled haploids, and it was suggested that the segregation of LG_11 were influenced by zygotic lethality or genotypic evaluation and that some deleterious recessive genes exist in LG_11 and reduce the viability of homozygotes with O. japonica alleles. It is very likely that a region of LG_11were responsible for the low frequencies of intra-gametophytic selfing in O. japonica.     

Excessive Cytokine Response to Rapid Proliferation of Highly Pathogenic Avian Influenza Viruses Leads to Fatal Systemic Capillary Leakage in Chickens

Highly pathogenic avian influenza viruses (HPAIVs) cause lethal infection in chickens. Severe cases of HPAIV infections have been also reported in mammals, including humans. In both mammals and birds, the relationship between host cytokine response to the infection with HPAIVs and lethal outcome has not been well understood. In the present study, the highly pathogenic avian influenza viruses A/turkey/Italy/4580/1999 (H7N1) (Ty/Italy) and A/chicken/Netherlands/2586/2003 (H7N7) (Ck/NL) and the low pathogenic avian influenza virus (LPAIV) A/chicken/Ibaraki/1/2005 (H5N2) (Ck/Ibaraki) were intranasally inoculated into chickens. Ty/Italy replicated more extensively than Ck/NL in systemic tissues of the chickens, especially in the brain, and induced excessive mRNA expression of inflammatory and antiviral cytokines (IFN-γ, IL-1β, IL-6, and IFN-α) in proportion to its proliferation. Using in situ hybridization, IL-6 mRNA was detected mainly in microglial nodules in the brain of the chickens infected with Ty/Italy. Capillary leakage assessed by Evans blue staining was observed in multiple organs, especially in the brains of the chickens infected with Ty/Italy, and was not observed in those infected with Ck/NL. In contrast, LPAIV caused only local infection in the chickens, with neither apparent cytokine expression nor capillary leakage in any tissue of the chickens. The present results indicate that an excessive cytokine response is induced by rapid and extensive proliferation of HPAIV and causes fatal multiple organ failure in chickens.     

Glutathione maintenance is crucial for survival of melanocytes after exposure to rhododendrol

Rhododendrol is a phenolic compound that shows a tyrosinase‐dependent toxicity for melanocytes and occasionally induces a vitiligo‐like skin depigmentation. The post‐tyrosinase mechanisms determining melanocyte death or survival, however, are far from clear. Here, we find that rhododendrol treatment leads to a reduction in the levels of cellular glutathione but also induces a cellular antioxidant response that eventually increases glutathione levels. We further find that rhododendrol toxicity is enhanced when glutathione levels are experimentally reduced and alleviated when glutathione levels are increased. Hence, it appears that the size of the preexisting glutathione pool along with the capacity to supply glutathione via the antioxidant response determines whether melanocytes survive or die after rhododendrol exposure. It is conceivable, therefore, that rhododendrol‐induced leukoderma depends on the capacity to maintain appropriate glutathione levels and that enhancement of glutathione levels may preserve a patient's melanocytes and potentially help in repigmentation.     

Metabolic Syndrome Components Are Associated with Intervertebral Disc Degeneration: The Wakayama Spine Study

Objective

The objective of the present study was to examine the associations between metabolic syndrome (MS) components, such as overweight (OW), hypertension (HT), dyslipidemia (DL), and impaired glucose tolerance (IGT), and intervertebral disc degeneration (DD).

Design

The present study included 928 participants (308 men, 620 women) of the 1,011 participants in the Wakayama Spine Study. DD on magnetic resonance imaging was classified according to the Pfirrmann system. OW, HT, DL, and IGT were assessed using the criteria of the Examination Committee of Criteria for MS in Japan.

Results

Multivariable logistic regression analysis revealed that OW was significantly associated with cervical, thoracic, and lumbar DD (cervical: odds ratio [OR], 1.28; 95% confidence interval [CI], 0.92–1.78; thoracic: OR, 1.75; 95% CI, 1.24–2.51; lumbar: OR, 1.87; 95% CI, 1.06–3.48). HT and IGT were significantly associated with thoracic DD (HT: OR, 1.54; 95% CI, 1.09–2.18; IGT: OR, 1.65; 95% CI, 1.12–2.48). Furthermore, subjects with 1 or more MS components had a higher OR for thoracic DD compared with those without MS components (vs. no component; 1 component: OR, 1.58; 95% CI, 1.03–2.42; 2 components: OR, 2.60; 95% CI, 1.62–4.20; ≥3 components: OR, 2.62; 95% CI, 1.42–5.00).

Conclusion

MS components were significantly associated with thoracic DD. Furthermore, accumulation of MS components significantly increased the OR for thoracic DD. These findings support the need for further studies of the effects of metabolic abnormality on DD.     

Structural Analysis of Free N-Glycans in α-Glucosidase Mutants of Saccharomyces cerevisiae: Lack of the Evidence for the Occurrence of Catabolic α-Glucosidase Acting on the N-Glycans

Saccharomyces cerevisiae produces two different α-glucosidases, Glucosidase 1 (Gls1) and Glucosidase 2 (Gls2), which are responsible for the removal of the glucose molecules from N-glycans (Glc₃Man₉GlcNAc₂) of glycoproteins in the endoplasmic reticulum. Whether any additional α-glucosidases playing a role in catabolizing the glucosylated N-glycans are produced by this yeast, however, remains unknown. We report herein on a search for additional α-glucosidases in S. cerevisiae. To this end, the precise structures of cytosolic free N-glycans (FNGs), mainly derived from the peptide:N-glycanase (Png1) mediated deglycosylation of N-glycoproteins were analyzed in the endoplasmic reticulum α-glucosidase-deficient mutants. 12 new glucosylated FNG structures were successfully identified through 2-dimentional HPLC analysis. On the other hand, non-glucosylated FNGs were not detected at all under any culture conditions. It can therefore be safely concluded that no catabolic α-glucosidases acting on N-glycans are produced by this yeast.     

Role of IGFBP7 in Diabetic Nephropathy: TGF-β1 Induces IGFBP7 via Smad2/4 in Human Renal Proximal Tubular Epithelial Cells

Tubular injury is one of the important determinants of progressive renal failure in diabetic nephropathy (DN), and TGF-β1 has been implicated in the pathogenesis of tubulointerstitial disease that characterizes proteinuric renal disease. The aim of this study was to identify novel therapeutic target molecules that play a role in the tubule damage of DN. We used an LC-MS/MS-based proteomic technique and human renal proximal epithelial cells (HRPTECs). Urine samples from Japanese patients with type 2 diabetes (n = 46) were used to quantify the candidate protein. Several proteins in HRPTECs in cultured media were observed to be driven by TGF-β1, one of which was 33-kDa IGFBP7, which is a member of IGFBP family. TGF-β1 up-regulated the expressions of IGFBP7 mRNA and protein in a dose- and time-dependent fashion via Smad2 and 4, but not MAPK pathways in HRPTECs. In addition, the knockdown of IGFBP7 restored the TGF-β1-induced epithelial to mesenchymal transition (EMT). In the immunohistochemical analysis, IGFBP7 was localized to the cytoplasm of tubular cells but not that of glomerular cells in diabetic kidney. Urinary IGFBP7 levels were significantly higher in the patients with macroalbuminuria and were correlated with age (r = 0.308, p = 0.037), eGFR (r = −0.376, p = 0.01), urinary β₂-microglobulin (r = 0.385, p = 0.008), and urinary N-acetyl-beta-D-glucosaminidase (NAG) (r = 0.502, p = 0.000). A multivariate regression analysis identified urinary NAG and age as determinants associated with urinary IGFBP7 levels. In conclusion, our data suggest that TGF-β1 enhances IGFBP7 via Smad2/4 pathways, and that IGFBP7 might be involved in the TGF-β1-induced tubular injury in DN.     

Macroinvertebrate assemblages in an artificial habitat—a settling basin of a hydroelectric power plant: comparison with a natural riffle habitat

The macroinvertebrate assemblages in an artificial habitat, the settling basin of a hydroelectric power plant, were investigated and compared with those in a natural habitat, riffles in a nearby river. This study showed that macroinvertebrate density was much higher in the settling basin than in the riffles. Macroinvertebrate assemblage composition differed between the settling basin and the riffles. The difference was probably due to the widespread bryophyte beds in the settling basin. Cincticostella, Brachycentrus, Ephmerella, and chironomid midges, which are usually abundant in bryophyte beds, were present at much higher densities in the settling basin. Cheumatopsyche and Taeniopterygidae were also present at higher densities in the settling basin than in the natural riffles. In contrast, Epeorus was present at lower density in the settling basin than in the natural riffles. This study suggests that the settling basin increases β-diversity in riverine ecosystems.     

Characterization of the reaction of decoupling ubiquinone with bovine mitochondrial respiratory complex I

We previously produced the unique ubiquinone QT (“decoupling” quinone), the catalytic reduction of which in NADH-quinone oxidoreduction with bovine heart mitochondrial NADH-ubiquinone oxidoreductase (complex I) is completely decoupled from proton translocation across the membrane domain. This feature is markedly distinct from those of typical short-chain quinones such as ubiquinone-1. To further characterize the features of the QT reaction with complex I, we herein synthesized three QT analogs, QT2–QT4, and characterized their electron transfer reactions. We found that all aspects of electron transfer (e.g. electron-accepting activity and membrane potential formation) vary significantly among these analogs. The features of QT2 as decoupling quinone were slightly superior to those of original QT. Based on these results, we conclude that the bound positions of QTs within the quinone binding cavity susceptibly change depending on their side-chain structures, and the positions, in turn, govern the behavior of QTs as electron acceptors.