Ectomycorrhizal fungal community of naturally regenerated Pinus thunbergii seedlings in a coastal pine forest

To add to knowledge of ectomycorrhizal (ECM) community structure on the roots of Pinus thunbergii seedlings in a Japanese coastal forest, we sampled naturally regenerated current-year and 1- to 5-year-old seedlings. We classified the 667 root tips on current-year seedlings and the 1,927 root tips on older seedlings into 13 phylotypes based on morphological and genetic analyses. Cenococcum geophilum, members of the families Clavulinaceae, Russulaceae, or Thelephoraceae or the genus Trichophaea, were indicated to be fungi forming P. thunbergii ectomycorrhizas. Among them, C. geophilum and Clavulinaceae sp. 1 were the most or second most dominant species. A species accumulation curve based on the number of samples nearly reached a plateau, with observed species richness equal to 11 species and the Jackknife2 and Chao2 richness estimators indicating 14 and 12 species, respectively. In addition, Simpson’s 1/D was 3.89 and Shannon–Wiener’s H′ was 1.71, indicating a relatively low taxonomic diversity. There was no significant difference in the ectomycorrhizal formation rate, or the occurrence frequency and the number of ECM phylotypes between current-year and older seedlings. These results indicated that less diverse fungi were involved in ectomycorrhizal formation on coastal pine seedlings compared with those in comparable inland forests in the study area.     

Site-level model–data synthesis of terrestrial carbon fluxes in the CarboEastAsia eddy-covariance observation network: toward future modeling efforts

Based on the model–data comparison at the eddy-covariance observation sites from CarboEastAsia datasets, we report the current status of the terrestrial carbon cycle modeling in monsoon Asia. In order to assess the modeling performance and discuss future requirements for both modeling and observation efforts in Asia, we ran eight terrestrial biosphere models at 24 sites from 1901 to 2010. By analyzing the modeled carbon fluxes against the CarboEastAsia datasets, the strengths and weaknesses of terrestrial biosphere modeling over Asia were evaluated. In terms of pattern and magnitude, the carbon fluxes (i.e., gross primary productivity, ecosystem respiration, and net ecosystem exchange) at the temperate and boreal forest sites were simulated best, whereas the simulation results from the tropical forest, cropland, and disturbed sites were poor. The multi-model ensemble mean values showed lower root mean square errors and higher correlations, suggesting that composition of multiple terrestrial biosphere models would be preferable for terrestrial carbon budget assessments in Asia. These results indicate that the current model-based estimation of terrestrial carbon budget has large uncertainties, and future research should further refine the models to permit re-evaluation of the terrestrial carbon budget.     

Zoosporicidal activity of polyflavonoid tannin identified in Lannea coromandelica stem bark against phytopathogenic oomycete Aphanomyces cochlioides

In a survey of nonhost plant secondary metabolites regulating motility and viability of zoospores of the Aphanomyces cochlioides, we found that stem bark extracts of Lannea coromandelica remarkably inhibited motility of zoospores followed by lysis. Bioassay-guided fractionation and chemical characterization of Lannea extracts by MALDI-TOF-MS revealed that the active constituents were angular type polyflavonoid tannins. Commercial polyflavonoid tannins, Quebracho and Mimosa, also showed identical zoosporicidal activity. Against zoospores, the motility-inhibiting and lytic activities were more pronounced in Lannea extracts (MIC 0.1 microg/mL) than in Quebracho (MIC 0.5 microg/mL) and Mimosa (MIC 0.5 microg/mL). Scanning electron microscopic observation visualized that both Lannea and commercial tannins caused lysis of cell membrane followed by fragmentation of cellular materials. Naturally occurring polyflavonoid tannin merits further study as potential zoospore regulating agent or as lead compound. To the best of our knowledge, this is the first report of zoosporicidal activity of natural polyflavonoid tannins against an oomycete phytopathogen.     

Regulatory effect of amino acids on the pasting behavior of potato starch is attributable to its binding to the starch chain

The binding of an amino acid, glycine (Gly), alanine (Ala), epsilon-aminocaproic acid (-AC), monosodium glutamate (GluNa), or lysine (Lys), to starch was examined by a biomolecular interaction analyzer (IAsys). A starch sample (ATS) hydrolyzed to an extent of 1% hydrolysis rate with 15% sulfuric acid was used as a model starch for the binding examination. The reducing end of ATS was oxidized by the Somogyi reagent, and the conversion of the reducing end to the carboxyl group of ATS was confirmed by a carboxylic acid fluorescence labeling reagent. The oxidized ATS was immobilized to the amino group of a sensor cuvette by using water-soluble carbodiimide and N-hydroxysuccinimide through an amide bond. The IAsys examination showed that Gly, Ala, and epsilon-AC scarcely bound to the immobilized starch chains but that GluNa and Lys favorably bound with their increasing concentrations. The relative binding index (RBI) of each amino acid was defined by the ratio of the slope of the linear regression equation between the binding response and the concentration for each amino acid to that for Gly. Because the relationships between the RBI and the pasting characteristics (pasting temperature, peak viscosity, breakdown, and swelling index) could each be expressed by a linear regression equation with a high correlation coefficient, it is concluded that the regulation of the pasting behavior of starch with an amino acid is caused by binding of the amino acid to the starch chains.     

Evaluation of greenhouse gas emissions in a Miscanthus sinensis Andersson-dominated semi-natural grassland in Kumamoto,Japan

Increasing greenhouse gas emissions from anthropogenic activities continue to be a mounting problem worldwide. In the semi-natural Miscanthus sinensis Andersson; grasslands of Aso, Kumamoto, Japan, which have been managed for thousands of years, we measured soil methane (CH₄) and nitrous oxide (N₂O) emissions before and after annual controlled burns. We estimated annual soil carbon (C) accumulation, and CH₄ and N₂O emissions induced by biomass burning in 2009 and 2010, to determine the impacts of this ecosystem and its management on global warming. Environmental factors affecting soil CH₄ and N₂O fluxes were unknown, with no effect of annual burning observed on short-term soil CH₄ and N₂O emissions. However, deposition of charcoal during burning may have enhanced CH₄ oxidation and N₂O consumption at the study site, given that emissions (CH₄: ?4.33 kg C ha^?1 yr^?1, N₂O: 0.17 kg N ha^?1 yr^?1) were relatively lower than those measured in other land-use types. Despite significant emission of CH₄ and N₂O during yearly burning events in early spring, the M. sinensis semi-natural grassland had a large annual soil C accumulation, which resulted in a global warming potential of ?4.86 Mg CO₂eq ha^?1 yr^?1. Consequently, our results indicate that long-term maintenance of semi-natural M. sinensis grasslands by annual burning can contribute to the mitigation of global warming.     

Comparison of lysophospholipid levels in rat feces with those in a standard chow

Although lysophospholipids have attracted much attention due to their diverse physiological activities through their specific receptors, little is known about their metabolic fates in mammalian digestive systems after their ingestion as a minor food component. In this study, we analyzed five lysophospholipids in lipid extracts of a standard rat chow and feces of rats fed the chow by two-dimensional thin layer chromatography and liquid chromatography-tandem mass spectrometry. The most abundant lysophospholipid in the rat chow was lysophosphatidylcholine followed by lysophosphatidylethanolamine, lysophosphatidic acid (LPA), lysophosphatidylinositol and lysophosphatidylserine (LPS) in an increasing order, but their concentrations were very low in rat feces. Among the molecular species of LPS in the chow, only saturated species were detected in the feces in significant amounts. In addition, several molecular species of LPA remained in the feces in variable portions (saturated > monounsaturated > polyunsaturated). These results suggest that a portion of ingested LPA and LPS reach the rat large intestine, affecting physiological colon functions.     

Localization of connexin 32 in spontaneous liver lesions of mice

We examined the localization of connexin 32 (Cx32), a component of gapjunctions, in 24-month-old male B6C3F1 mice with spontaneously occurring hepatocellularaltered foci or tumors. Immunohistochemically, Cx32-staining intensity in cell-to-cellmembranes of altered hepatocytes was decreased in eosinophilic foci and increased inbasophilic foci as compared to those in intact hepatocytes. These alterations wereenhanced in adenomas and carcinomas with both eosinophilic and basophilic cytoplasm. Incell membranes facing on the sinusoidal portions, the intensities increased in alllesions. Image analyses confirmed that the spot areas of Cx32 were decreased ineosinophilic foci, but increased in basophilic foci, adenomas and carcinomas. Theseresults demonstrate that Cx32 shows different expression in different types of hepaticlesions.     

Nuclear transfer in cattle : effect of linoleic acid-albumin on freezing sensitivity of enucleated oocytes

The effect of linoleic acid-albumin (LAA) supplementation to the media for IVM, enucleation, and activation on the developmental potential of bovine embryos produced by nuclear transfer (NT) into frozen-thawed cytoplasts was investigated. Blastomeres derived from morulae was placed in the perivitelline space of frozen-thawed cytoplasts, which were then fused by a DC pulse. The proportion of fused embryos was similar between groups with and without LAA (87 vs. 90%). The proportion of development to blastocysts of NT embryos derived from the media with LAA (14%) was higher than that without LAA (4%), indicating that LAA treatment of bovine oocytes during IVM, enucleation and activation can improve the ability of such cytoplasts after freezing and thawing to develop into blastocysts after NT.     

Drop of egg production in chickens by experimental infection with an avian metapneumovirus strain PLE8T1 derived from swollen head syndrome and the application to evaluate vaccine

Decreases in egg production and increased incidence of abnormal eggs due to malformation of egg shells were observed in specific pathogen free (SPF) 173-day-old laying hens inoculated intravenously with an avian metapneumovirus (aMPV) strain PLE8T1. This strain was derived from an isolate from broiler birds exhibiting swollen head syndrome (SHS). Some SPF birds inoculated with the virus showed, slight diarrhea without any respiratory symptoms. Thus, the PLE8T1 strain was used as a challenge virus to evaluate efficacy of aMPV vaccines. SPF chickens which received a live attenuated aMPV vaccine (NEMOVAC; Merial) at 7 or 77 days old and an inactivated aMPV vaccine (OVO-4; Merial) at 105 days old were protected against poor egg production caused by the challenge with the PLE8T1 strain. Thus, aMPV, the PLE8T1 strain passaged 22 times after isolation, from birds exhibiting SHS, could induce a drop in egg production in laying hens accompanied by malformation of egg shells. It was suggested that this challenge system could be applied to evaluate the efficacy of aMPV vaccine.