Study on the determination of pesticide residues in crops by ion-trap GC/MS/MS

Ion-trap GC/MS/MS was evaluated for the multi-residue determination of pesticides in agricultural products. Matrices were extracted from samples (spinach, carrot, onion and brown rice) with acetone and submitted to gel permeation chromatography, followed by a clean-up step through a graphite carbon cartridge. Thirty-five pesticides were added to either matrix, and analyzed by GC/MS/MS. Detection limits of pesticides by GC/MS/MS was almost the same as those by GC/MS (SIM). Coefficients of variation of peak area in 5 measurements of each pesticide at 0.1 microgram/mL or 0.05 microgram/mL with or without matrices were mostly acceptable, though those of 20 pesticides out of 35 were higher than 10% at a concentration of 0.02 microgram/mL. It was indicated that matrix artifacts, which interfere with GC/MS-Scan analysis, could be eliminated in some cases by using GC/MS/MS.     

Comparison of DNA sequencing analysis with phenotyping test for identification of yeasts isolated from foods

The identification of 20 strains of yeasts isolated from foods by means of DNA sequence analysis with two kinds of universal primers for the rDNA region was examined, and the results were compared with those of the conventional phenotyping test using API 20C AUX. In the analysis of the 26S region, all 20 yeast strains tested were identified at the species level. In the ITS1 region, 16 strains were also classified at the species level. In addition, all results of DNA sequence analysis were consistent with those of the phenotyping test at the genus level. Furthermore, DNA sequence analysis was able to identify causative yeasts observed in two suspect foods, though phenotyping tests alone failed to identify them.     

Distribution, diversity and regulation of alcohol oxidase isozymes, and phylogenetic relationships of methylotrophic yeasts

In this study, we attempted to classify the methylotrophic yeasts based on diversities of alcohol oxidase (AOD), i.e. zymogram patterns and partial amino acid sequences. According to zymogram patterns for AOD, members of the methylotrophic yeasts separate into two major lineages, one group involving strains having a single AOD and the other group, including Pichia methanolica, Candida pignaliae and C. sonorensis, showing nine AOD isozymes. Based on partial amino acid sequences of AOD, the methylotrophic yeasts could be divided into five groups, and this classification agrees mostly with grouping based on 26S domain D1/D2 rDNA nucleotide sequences, except for some strains. Moreover, the strains having AOD isozymes constitute one group with P. trehalophila, P. glucozyma and Pichia sp. strain BZ159, although these strains are divided into two types, based on amino acid sequences of second AODs. On the other hand, these AOD isozymes consist of two subunits; the first subunits are induced not only by methanol but also by glycerol and pectin, although the second subunits are mainly induced by methanol. These data indicate that AOD isozymes and second AOD genes distribute widely in several methylotrophic yeasts in the natural environment, and second AOD genes may have evolved as methylotrophic genes that can adapt to the environmental conditions of higher methanol concentrations.     

Spatial distributions and profiles of atmospheric polycyclic aromatic hydrocarbons in two industrial cities in Japan

The spatial distribution and concentration profiles of 39 vapor and particulate polycyclic aromatic hydrocarbons (PAHs) have been investigated in two Japanese industrial cities (Fuji and Shimizu; a summer and winter season in each). The concentrations of particulate PAHs in winter tended to be higher than those in the summer, but for vapor PAHs, this was not the case. Significant correlations (p < 0.01) were found between most of the PAH concentrations monitored in winter, suggesting the presence of common emission sources. To identify PAH spatial distributions and emission sources in the area, we created contour maps for PAHs monitored; this indicates that the distinctive local distributions correspond to the emission sources. PAH profiles based on benzo[e]pyrene (BeP) concentration, especially for certain relatively heavy molecular weight PAHs, showed differential behaviors among divided areas related to potential regional emission sources such as paper-making plants, power plants, and traffic. We conclude that the origins of atmospheric PAHs in the surveyed areas were dominated by not only traffic but also by stationary emission sources such as paper-making plants and power plants and that local distributions were dependent on the local wind direction.     

Cloning and heterologous expression of a beta-fructofuranosidase gene from Arthrobacter globiformis IFO 3062, and site-directed mutagenesis of the essential aspartic acid and glutamic acid of the active site

We have cloned the gene encoding a beta-fructofuranosidase from Arthrobacter globiformis IFO 3062, and subsequently, the gene was heterologously expressed in Escherichia coli. This beta-fructofuranosidase gene encodes a protein of 548 amino acid residues with a calculated molecular mass of 60,519 Da. We have examined the roles of three residues of A. globiformis IFO 3062 beta-fructofuranosidase by site-directed mutagenesis, and found that aspartic acid 130 and glutamic acid 392, which are two of the apparent catalytic residues, are essential for hydrolase activity. This study provides the first experimental evidence showing that these two amino acid residues of beta-fructofuranosidase play a critical role in hydrolyzing sucrose.     

Isolation and Characterization of Two Types of Xyloglucanases from a Phytopathogenic Fungus,Verticillium dahliae

Xyloglucan is a major hemicellulosic component in plant cell walls. Phytopathogenic fungi secrete cell wall-degrading enzymes on their infection to hosts, while the nature of the cell wall-lytic enzymes of such fungi are yet to be fully understood. Verticillium dahliae is a soil-borne fungus that causes vascular wilt diseases in a variety of commercially important crops worldwide. We purified two types of xyloglucanases, XEG12A and XEG74B, from the culture of naturally isolated Verticillium dahliae strain 2148. XEG12A showed a molecular size of 23 kDa with its maximal activity at pH 7.5. XEG12A specifically hydrolyzed xyloglucan with no activity on other β-glucans. XEG74B had a molecular size of 110 kDa with its optimum pH at 6.0. XEG74B primarily hydrolyzed xyloglucan, with a slight activity on β-1,3-1,4-glucan. Analysis of hydrolytic products of xyloglucanooligasaccharide (XXXGXXXG) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) revealed that the both enzymes cleaved β-1,4-glucosidic linkage at the position of unbranched chain, while XEG74B showed a little fluctuation with the cleavage site. Both enzymes did not hydrolyzed xyloglucanoheptasaccharide (XXXG) at all. N-Terminal and internal amino acid sequencing of the enzymes revealed that XEG12A and XEG74B belonged to Glycoside Hydrolase (GH) Families 12 and 74, respectively. Based on these results we concluded that V. dahliae XEG12A and XEG74B were xyloglucan-specific endo-β-1,4-glucanases (EC 3.2.1.151).     

Effects of Phosphoryl Oligosaccharides of Calcium (POs-Ca) on Mycelial Growth and Fruiting Body Development of the Edible Mushroom,Pleurotus ostreatus

Phosphoryl oligosaccharides of calcium (POs-Ca) is a calcium salt of phosphoryl maltooligosaccharides made from potato starch. POs-Ca is highly water-soluble and can supply both the calcium ion and acidic oligosaccharides in an aqueous solution. In this study, we investigated the effects of POs-Ca on the mycelial growth and fruiting body yield of Pleurotus ostreatus , which is one of the most widely cultivated edible mushrooms in the world. We cultivated the mushroom using both potato dextrose agar (PDA) medium and sawdust-based medium, with added calcium salts. The addition of POs-Ca into the PDA medium with a calcium concentration of 10 mg increased mycelial growth significantly ( p < 0.05, vs . control). POs-Ca addition to the sawdust-based medium at concentrations of 1.0 to 3.0 g/100 g medium increased the amount of calcium in the fruiting bodies but did not affect the length of the cultivation period or the weight of the fruiting body. The calcium content in the fruiting body increased 12-fold when compared to the control. On the other hand, neither the CaHPO ₄ ･2H ₂ O group nor the CaHPO ₄ ･2H ₂ O with oligosaccharides group showed changes in the calcium content of the fruiting bodies. Our results indicate that the use of POs-Ca in mushroom cultivation allows for the possibility of developing new functional foods like calcium-enriched edible mushrooms. This is the first report describing the effects of POs-Ca on mushroom cultivation.     

Treatment capability of an up-flow anammox column reactor using polyethylene sponge strips as biomass carrier

The feasibility of applying a polyethylene (PE) sponge as a biomass carrier in an anaerobic ammonium oxidation (anammox) reactor and its nitrogen removal performance were also investigated. Experiments were carried out in an up-flow column reactor with synthetic inorganic wastewater. Experimental results indicate that reactor containing PE sponge biomass carriers showed a high nitrogen removal capability and exhibited stable performance. In addition, the reactor with 8 strips PE sponge as biomass carrier exhibited greater adaptation capacity compared to that with 6 strips and could achieve a high TN removal rate within a very short period. The ratio of NO₂-N removal and NO₃-N production to NH₄-N removal for the reactor was 1.26:0.21. Furthermore, to investigate the bacterial composition of the mature community, 16S rRNA sequences were amplified by PCR and analyses were conducted using DNA databases. Results showed that a new kind of anammox microorganism (Kumadai-1) was the dominant species in the reactor when using PE sponge as a biomass carrier.     

日本造纸工业现状与技术进步

2006年日本纸和纸板的总产量是5110．5万吨,仅次于美国和中国,位列世界第三。日本制浆造纸工业的特点是进口木片,然后在本土生产纸浆和纸。由于国内消费量不再增长,日本不得不慎重对待进口纸。中国的影响将成为一个大问题,而公司的社会责任则是另一个大问题。     

The absence of corpus luteum formation alters the endocrine profile and affects follicular development during the first follicular wave in cattle

We previously established a bovine experimental model showing that the corpus luteum (CL) does not appear following aspiration of the preovulatory follicle before the onset of LH surge. Using this model, the present study aimed to determine the profile of follicular development and the endocrinological environment in the absence of CL with variable nadir circulating progesterone (P(4)) concentrations during the oestrous cycle in cattle. Luteolysis was induced in heifers and cows and they were assigned either to have the dominant follicle aspirated (CL-absent) or ovulation induced (CL-present). Ultrasound scanning to observe the diameter of each follicle and blood collection was performed from the day of follicular aspiration or ovulation and continued for 6 days. The CL-absent cattle maintained nadir circulating P(4) throughout the experimental period and showed a similar diameter between the largest and second largest follicle, resulting in co-dominant follicles. Oestradiol (E(2)) concentrations were greater in the CL-absent cows than in the CL-present cows at day -1, day 1 and day 2 from follicular deviation. The CL-absent cows had a higher basal concentration, area under the curve (AUC), pulse amplitude and pulse frequency of LH than the CL-present cows. After follicular deviation, the CL-absent cows showed a greater basal concentration, AUC and pulse amplitude of growth hormone (GH) than the CL-present cows. These results suggest that the absence of CL accompanying nadir circulating P(4) induces an enhancement of LH pulses, which involves the growth of the co-dominant follicles. Our results also suggest that circulating levels of P(4) and E(2) affect pulsatile GH secretion in cattle.