Decrease in fungal biodiversity along an available phosphorous gradient in arable Andosol soils in Japan.

Andosols comprise one of the most important soil groups for agricultural activities in Japan because they cover about 46.5% of arable upland fields. In this soil group, available phosphorus (P) is accumulated by application of excessive fertilizer, but little is known about the influence of increasing P availability on microbial community diversity at large scales.

Application of a fluorometric microplate algal toxicity assay for riverine periphytic algal species.

Although riverine periphytic algae attached to riverbed gravel are dominant species in flowing rivers, there is limited toxicity data on them because of the difficulty in cell culture and assays. Moreover, it is well known that sensitivity to pesticides differ markedly among species, and therefore the toxicity data for multiple species need to be efficiently obtained. In this study, we investigated the use of fluorometric microplate toxicity assay for testing periphytic algal species.

Genome-wide screening to study breeding methods to improve the nitrogen accumulation ability of yeast without gene recombinant techniques.

To remove nitrogen efficiently from high-concentration organic wastewater, we studied breeding methods using Saccharomyces cerevisiae as a model yeast with improved nitrogen accumulation ability. By DNA microarray analysis under various nitrogen concentrations with two nitrogen sources (peptone and L-asparagine), we obtained 295 commonly overexpressed (over 2-fold) genes and 283 commonly underexpressed (under one-half) genes under nitrogen-starvation conditions. We speculated that overexpression or underexpression recombination of some of these genes might enhance nitrogen uptake.

Reduction of hazardous organic solvent in sample preparation for hydrophilic pesticide residues in agricultural products with conventional liquid chromatography.

An original extraction method using water as an extractant has been established for environmentally friendly sample preparation procedures for hydrophilic pesticides (acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, methomyl, pymetrozine, thiacloprid, and thiamethoxam) in agricultural samples with conventional HPLC. Water-based extraction and cleanup with two solid-phase extraction cartridges can recover target hydrophilic pesticides quantitatively. The matrix effects of tested samples on the proposed method developed herein were negligibly small.

Canopy-scale relationships between stomatal conductance and photosynthesis in irrigated rice.

Modeling stomatal behavior is critical in research on land-atmosphere interactions and climate change. The most common model uses an existing relationship between photosynthesis and stomatal conductance. However, its parameters have been determined using infrequent and leaf-scale gas-exchange measurements and may not be representative of the whole canopy in time and space.

Linking temperature sensitivity of soil organic matter decomposition to its molecular structure, accessibility, and microbial physiology.

Temperature sensitivity of soil organic matter (SOM) decomposition may have a significant impact on global warming. Enzyme-kinetic hypothesis suggests that decomposition of low-quality substrate (recalcitrant molecular structure) requires higher activation energy and thus has greater temperature sensitivity than that of high-quality, labile substrate. Supporting evidence, however, relies largely on indirect indices of substrate quality.

Rice cultivar responses to elevated CO at two free-air CO enrichment (FACE) sites in Japan.

There is some evidence that rice cultivars respond differently to elevated CO2 concentrations ([CO2]), but [CO2]×cultivar interaction has never been tested under open-field conditions across different sites. Here, we report on trials conducted at free-air CO2 enrichment (FACE) facilities at two sites in Japan, Shizukuishi (2007 and 2008) and Tsukuba (2010). The average growing-season air temperature was more than 5°C warmer at Tsukuba than at Shizukuishi.

Spatial distribution and management of isolated woody plants traditionally used as farmland boundary markers in Ibaraki Prefecture, Japan.

Although noncrop woody plants in crop field landscapes serve multiple functions, the modernization of agriculture has threatened their preservation. In this study, isolated woody plants used as farmland boundary markers were investigated in Ibaraki Prefecture in the eastern Kanto region. A total of 2001 individuals of 50 species were found around 177 equidistantly spaced points.

Enzymatic degradation of polyester films by a cutinase-like enzyme from Pseudozyma antarctica: surface plasmon resonance and atomic force microscopy study.

Enzymatic degradation of polyester films by a cutinase-like enzyme from Pseudozyma antarctica JCM10317 (PaE) was analyzed by surface plasmon resonance (SPR). The adsorption of PaE and the degradation rate for polyester films were quantitatively monitored by a positive and negative SPR signal shifts, respectively. The decrease in SPR signal and the erosion depth of amorphous poly(L-lactide) (a-PLLA) film measured by atomic force microscopy (AFM) had a linear relationship, and the weight loss was estimated from the AFM data combined with a density of a-PLLA film.

Taxonomic review of the genus Rhinoncomimus (Coleoptera: Curculionidae: Ceutorhynchinae) with description of a new species from Yunnan, China.

The genus Rhinoncomimus Wagner, 1940 includes seven species from Eastern Asia. One new species, Rh. continuus sp.

Bacterial cytochrome P450 system catabolizing the Fusarium toxin deoxynivalenol.

Deoxynivalenol (DON) is a natural toxin of fungi that cause Fusarium head blight disease of wheat and other small-grain cereals. DON accumulates in infected grains and promotes the spread of the infection on wheat, posing serious problems to grain production. The elucidation of DON-catabolic genes and enzymes in DON-degrading microbes will provide new approaches to decrease DON contamination.

Affinity purification and characterization of a biodegradable plastic-degrading enzyme from a yeast isolated from the larval midgut of a stag beetle, Aegus laevicollis.

Two yeast strains, which have the ability to degrade biodegradable plastic films, were isolated from the larval midgut of a stag beetle, Aegus laevicollis. Both of them are most closely related to Cryptococcus magnus and could degrade biodegradable plastic (BP) films made of poly(butylene succinate) (PBS) and poly(butylene succinate-co-adipate) (PBSA) effectively. A BP-degrading enzyme was purified from the culture broth of one of the isolated strains employing a newly developed affinity purification method based on the binding action of the enzyme to the substrate (emulsified PBSA) and its subsequent degradative action toward the substrate.

Rapid and simple immunochemical screening combined with hand-shaking extraction for thiamethoxam residue in agricultural products.

Background: With the aim of expanding the applicability of a kit-based enzyme-linked immunosorbent assay (ELISA) for the neonicotinoid insecticide thiamethoxam, the ELISA was newly applied to three kinds of agricultural samples (green pepper, eggplant and spinach). To offer the ELISA as a screening analysis for thiamethoxam residues, a rapid and simple method of extraction by hand-shaking was used, and speed-up and simplification of the sample treatment before the ELISA analysis were examined. Finally, the validity of the ELISA combined with the proposed extraction method was verified against a reference high-performance liquid chromatography (HPLC) method using real-world agricultural samples.

Quantification of canavanine, 2-aminoethanol, and cyanamide in Aphis craccivora and its host plants, Robinia pseudoacacia and Vicia angustifolia: effects of these compounds on larval survivorship of Harmonia axyridis.

The cowpea aphid Aphis craccivora that infests the black locust Robinia pseudoacacia shows toxicity to its predator, the multicolored Asian ladybird beetle, Harmonia axyridis. In contrast, the same aphid species that infests the common vetch, Vicia angustifolia, is suitable prey for H. axyridis larvae.

Ion-beam irradiation, gene identification, and marker-assisted breeding in the development of low-cadmium rice.

Rice (Oryza sativa L.) grain is a major dietary source of cadmium (Cd), which is toxic to humans, but no practical technique exists to substantially reduce Cd contamination. Carbon ion-beam irradiation produced three rice mutants with <0.

Chitin-induced gene expression in secondary metabolic pathways of Streptomyces coelicolor A3(2) grown in soil.

Microarray analyses revealed that the expression of genes for secondary metabolism together with that of primary metabolic genes was induced by chitin in autoclaved soil cultures of Streptomyces coelicolor A3(2). The data also indicated that DasR was involved in the regulation of gene expression for chitin catabolism, secondary metabolism, and stress responses.

Quantitative analysis of fungicide azoxystrobin in agricultural samples with rapid, simple and reliable monoclonal immunoassay.

This work presents analytical performance of a kit-based direct competitive enzyme-linked immunosorbent assay (dc-ELISA) for azoxystrobin detection in agricultural products. The dc-ELISA was sufficiently sensitive for analysis of residue levels close to the maximum residue limits. The dc-ELISA did not show cross-reactivity to other strobilurin analogues.

[Reducing cadmium content of rice grains by means of flooding and a few problems].

The effects of water management in rice paddies on the levels of cadmium (Cd) and arsenic (As) in Japanese rice grains were tested. In order to reduce the Cd concentration in rice grains, flooding for 3 weeks before and after heading was most effective, but this treatment increased As concentration considerably. Aerobic treatment was effective in reducing As concentration in rice grains, but increased Cd concentration markedly.

Plant growth inhibitor from the Malaysian medicinal plant Goniothalamus andersonii and related species.

A crude methanol extract of Goniothalamus andersonii J. Sinclair strongly inhibited elongation of lettuce (Lactuca sativa L.) radicles.

A novel method for RNA extraction from Andosols using casein and its application to amoA gene expression study in soil.

The lack of a universal method to extract RNA from soil hinders the progress of studies related to nitrification in soil, which is an important step in the nitrogen cycle. It is particularly difficult to extract RNA from certain types of soils such as Andosols (volcanic ash soils), which is the dominant agricultural soil in Japan, because of RNA adsorption by soil. To obtain RNA from these challenging soils to study the bacteria involved in nitrification, we developed a soil RNA extraction method for gene expression analysis.

Rapid and simple colorimetric assay for detecting the enzymatic degradation of biodegradable plastic films.

We developed a rapid and simple method for evaluating the degradation of solid biodegradable plastics (BPs). Dye-containing BP films were used as substrates and the release of dye caused by the degradation of BPs was confirmed by a color change in the enzyme solution after a reaction time of 24 h.

Wellbore-wall compression effects on monitored groundwater levels and qualities.

The effects of wellbore-wall compression from rough excavation on monitored groundwater levels and qualities under natural hydraulic gradient conditions were investigated in a shallow clayey Andisol aquifer. Nine wellbores reaching the underlying aquitard at about 2.6-m depth were constructed by dynamic cone penetrometry to mimic rough wellbore construction.

Rapid and simple analysis of pesticides persisting on green pepper surfaces swabbing with solvent-moistened cotton.

A rapid and simple nondestructive extraction (NDE) method that includes wiping off of systemic neonicotinoid insecticides has been developed to streamline sample pretreatment procedures conducted before chromatographic determination. Pesticide residues were extracted from green pepper surfaces by swabbing them with absorbent cotton moistened with acetone or acetonitrile. After spraying of pesticides, the extraction rate decreased gradually, except for thiacloprid.

Degradation of biodegradable plastic mulch films in soil environment by phylloplane fungi isolated from gramineous plants.

To improve the biodegradation of biodegradable plastic (BP) mulch films, 1227 fungal strains were isolated from plant surface (phylloplane) and evaluated for BP-degrading ability. Among them, B47-9 a strain isolated from the leaf surface of barley showed the strongest ability to degrade poly-(butylene succinate-co-butylene adipate) (PBSA) and poly-(butylene succinate) (PBS) films. The strain grew on the surface of soil-mounted BP films, produced breaks along the direction of hyphal growth indicated that it secreted a BP-degrading enzyme, and has directly contributing to accelerating the degradation of film.