Landslide-facilitated species diversity in a beech-dominant forest

To evaluate the extent to which landslides affect community dynamics and consequent species diversity in a beech-dominated forest, differences in the composition and size structure of tree species were compared between landslide and adjacent stable (control) stands. Demography and changes in size were compared between the two stands over a 5-year period about 60 years after a landslide. In the control stand, replacement occurred even amongst late-successional species, with beech (Fagus crenata)—the most dominant species—increasing in relative abundance. In the landslide stand, very few large individuals of late-successional species occurred, whereas large individuals of early-successional species occurred only in the landslide stand. The traits indicate that the landslide strongly facilitated species diversity, not only by reducing the dominance of late-successional species, but also by promoting recruitment of early-successional species. However, new recruitment of early-successional species was inhibited in the landslide stand, although we observed succeeding regeneration and subsequent population growth of late-successional species there. As a result, the relative dominance of late-successional species increased with succession after the landslide, thus decreasing future species diversity. In beech-dominant forest landscapes in Japan that include communities with different developmental stages, the mosaic of serial stages may facilitate species diversity after a landslide.     

Studies on the Flavonoids in Tea Leaves

Yellow needle crystals, C₂₁H₂₀O₁₃?H₂O have been isolated from tea leaves. The crystals yield myricetin (hexaacetate, m.p. 211~212°C), glucose and galactose on hydrolysis. As analytical data indicate the molecular ratio of myricetin to the sugars to be 1:1 and the only bonding position of the sugars to be position 3 of the aglycone, the crystals are concluded to consist of two kinds of glycosides, namely myricetin-3-glucoside and myricetin-3-galactoside.     

Volatile Components of Quince Fruit (Cydonia oblonga Mill.)

Steam distilled oil of quince fruit (Cydonia oblonga Mill.=C. vulgaris Pers., marmelo in Japanese) was analyzed by gas chromatography and gas chromatography-mass spectrometry. Sixty-two compounds, 2 hydrocarbons, 13 esters, 11 alcohols, 11 aldehydes, 11 ketones, 5 lactones and 9 miscellaneous compounds, were identified. Of them, the chemical structures of two new oxide compounds, trans- and cis-3-methyl-5-[(E)-3′-methyl-13′-butadien-1′-yl]tetrahydrofuran, were elucidated by instrumental analyses.     

Mechanisms of the tRNA wobble cytidine modification essential for AUA codon decoding in prokaryotes

Bacteria and archaea have 2-lysylcytidine (L or lysidine) and 2-agmatinylcytidine (agm²C or agmatidine), respectively, at the first (wobble) position of the anticodon of the AUA codon-specific tRNA^Ile. These lysine- or agmatine-conjugated cytidine derivatives are crucial for the precise decoding of the genetic code. L is synthesized by tRNA^Ile-lysidine synthetase (TilS), which uses l-lysine and ATP as substrates. Agm²C formation is catalyzed by tRNA^Ile-agm²C synthetase (TiaS), which uses agmatine and ATP for the reaction. Despite the fact that TilS and TiaS synthesize structurally similar cytidine derivatives, these enzymes belong to non-related protein families. Therefore, these enzymes modify the wobble cytidine by distinct catalytic mechanisms, in which TilS activates the C2 carbon of the wobble cytidine by adenylation, while TiaS activates it by phosphorylation. In contrast, TilS and TiaS share similar tRNA recognition mechanisms, in which the enzymes recognize the tRNA acceptor stem to discriminate tRNA^Ile and tRNA^Met.     

Absolute Configuration of (+)-1-Acetoxy-p-menth-3-one Isolated from Essential Oil of Mentha gentilis (L.)

The most effective electro-energizing fermentation (E-E F) conditions for l-glutamate (l-Glu) production by Brevibacterium flavum No. 2247 were determined. The adding of 0.01 mm neutral red at the beginning of cultivation was found most effective. A 1.5 V direct current was applied to the culture broth at 6~8 hr after inoculation in the cathode compartment, l-Glu was produced at 51.0 mg per ml, and this is about a 15 % increase in yield compared to the yield of the not electro-energizing (E-E) control (44.3 mg/ml).     

Effect of repeated harvesting on the content of caffeic acid and seven species of caffeoylquinic acids in sweet potato leaves

The purpose of this study was to investigate the effect of repeated harvesting on the content of caffeic acid (CA) and seven species of caffeoylquinic acids (CQAs) in sweet potato leaves using a newly developed high-performance liquid chromatography method. Six cultivars and two breeding lines were used in this study. Leaves were collected at monthly intervals from 1st harvest (May) to 4th harvest (August) in 2011 and 2012. ANOVA analysis revealed that the contents of CQAs were significantly different among all cultivars and breeding lines, but no significant differences were found for CA. No annual variation was confirmed in CA and CQAs. Repeated harvest of sweet potato leaves affected the content of only 4-CQA and 5-CQA. Post-hoc comparisons using Tukey’s method indicated that the contents of 4-CQA and 5-CQA in sweet potato leaves harvested at first time were significantly higher compared to those at the other harvest times.     

Lactobacillus helveticus SBT2171 alleviates allergic symptoms in a murine model for pollen allergy

ABSTRACT

Lactic acid bacteria are known to have various health-promoting effects and are highly expected to find applications in anti-allergic food materials. In this study, we focused on Lactobacillus helveticus SBT2171 (LH2171), which reportedly modifies some unique immune responses and ameliorated symptoms of patients allergic to mites and house dust in the previous studies. We examined the effect of LH2171 on cytokine production by antigen-stimulated murine naïve splenocytes in vitro and demonstrated that it inhibited IL-4 and IL-13 production while enhancing IFN-γ and IL-10 production. Then, we examined the anti-allergic effect of LH2171 in vivo using a murine model of pollen allergy and found that LH2171 reduced the sneezing frequency when orally administered to mice. We successfully confirmed the immune modulatory activity of LH2171 and its anti-allergic activity against inhaled antigens. These evidences would contribute to identifying the anti-allergic mechanism of LH2171.

Abbreviations: ALDH: aldehyde dehydrogenase; EGCG: epigallocatechin gallate; LAB: lactic acid bacteria; LH2171: Lactobacillus helveticus SBT2171; NALT: nasal-associated lymphoid tissue; OVA: ovalbumin     

Phosphorylation of Arabidopsis thaliana MEKK1 via Ca2+ signaling as a part of the cold stress response

The Arabidopsis mitogen activated protein kinase kinase kinase (MEKK1) plays an important role in stress signaling. However, little is known about the upstream pathways of MEKK1. This report describes the regulation of MEKK1 activity during cold signaling. Immunoprecipitated MEKK1 from cold-treated Arabidopsis seedlings showed elevated kinase activity towards mitogen activated protein kinase kinase2 (MKK2), one of the candidate MEKK1 substrates. To clarify how MEKK1 becomes active in response to cold stress signaling, MEKK1 phosphorylation was monitored by an enzyme extracted from the seedlings grown under cold stress with or without EGTA. MEKK1 was phosphorylated after cold stress, but EGTA inhibited the phosphorylation. MKK2 was also phosphorylated by the same extract, but only when EGTA was absent. These results suggested that Ca²⁺ signaling occurred upstream of the MEKK1–MKK2 pathway. Full-length MEKK1 showed almost no activity but MEKK1 without the N-terminal region (MEKK1 KD) that retained the kinase domain had a strong ability to phosphorylate MKK2, demonstrating the inhibitory role of the N-terminal region of MEKK1. In addition, MEKK1 was phosphorylated by calcium/calmodulin-regulated receptor-like kinase (CRLK1), which suggested that CRLK1 is one of candidates located upstream of MEKK1.     

Square‐Centimeter‐Sized High‐Efficiency Polymer Solar Cells: How the Processing Atmosphere and Film Quality Influence Performance at Large Scale

Organic solar cells based on two benzodithiophene‐based polymers (PTB7 and PTB7‐Th) processed at square centimeter‐size under inert atmosphere and ambient air, respectively, are investigated. It is demonstrated that the performance of solar cells processed under inert atmosphere is not limited by the upscaling of photoactive layer and the interfacial layers. Thorough morphological and electrical characterizations of optimized layers and corresponding devices reveal that performance losses due to area enlargement are only caused by the sheet resistance of the transparent electrode reducing the efficiency from 9.3% of 7.8% for PTB7‐Th in the condition that both photoactive layer and the interfacial layers are of high layer quality. Air processing of photoactive layer and the interfacial layers into centimeter‐sized solar cells lead to additional, but only slight, losses (<10%) in all photovoltaic parameters, which can be addressed to changes in the electronic properties of both active layer and ZnO layers rather than changes in layer morphology. The demonstrated compatibility of polymer solar cells using solution‐processed photoactive layer and interfacial layers with large area indicates that the introduction of a standard active area of 1 cm² for measuring efficiency of organic record solar cells is feasible. However electric standards for indium tin oxides (ITO) or alternative transparent electrodes need to be developed so that performance of new photovoltaic materials can be compared at square centimeter‐size.