Suitable inflow rate and furrow length for simplified surge flow irrigation

Paddy and Water Environment - In the arid lands covering Uzbekistan, furrow irrigation with low application efficiency is still widely used due to a lack of funds and shortage of labor. To save...     

Seasonal variation of domoic acid in a bivalve Spondylus versicolor in association with that in plankton samples in Nha Phu Bay,Khanh Hoa,Vietnam

Previously we reported that a significant level of domoic acid, a causative toxin for amnesic shellfish poisoning, was detected in bivalves belonging to a genus Spondylus from various tropical Asian countries. These findings indicate that causative plankton species for domoic acid widely distribute in these areas. In the present study, we monitored seasonal change of domoic acid level of Spondylus versicolor in association with that of plankton samples in Nha Phu Bay, Khanh Hoa, Vietnam from December 2004 to October 2005. The toxicity of S. versicolor showed distinct seasonal variation. During the period when domoic acid level of S. versicolor was increasing, a significant level of domoic acid was detected in the plankton samples, showing the correlation between these two parameters. These findings show that plankton causative for domoic acid occurred in the bay, and S. versicolor accumulate domoic acid during a bloom of the toxic plankton by food web transfer.     

Genetic and genomic analyses for predicted methane‐related traits in Japanese Black steers

The objectives of this study were to estimate genetic parameters and to perform a genome‐wide association study (GWAS) for predicted methane‐related traits in Japanese Black steers. The methane production and yield traits were predicted using on‐farm measurable traits, such as dry matter intake and average daily gain. A total of 4,578 Japanese Black steers, which were progenies of 362 sires genotyped with imputed 551,995 single nucleotide polymorphisms (SNPs), had phenotypes of predicted methane‐related traits during the total fattening period (52 weeks). For the estimation of genetic parameters, the estimated heritabilities were moderate (ranged from 0.57 to 0.60). In addition, the estimated genetic correlations of methane production traits with most of carcass traits and feed‐efficiency traits were unfavorable, but those of methane yield traits were favorable or low. For the GWAS, no genome‐wide significant SNP was detected, but a total of four quantitative trait locus (QTL) regions that explained more than 5.0% of genetic variance were localized on the genome, and some candidate genes associated with growth and feed‐efficiency traits were located on the regions. Our results suggest that the predicted methane‐related traits are heritable and some QTL regions for the traits are localized on the genome in Japanese Black steers.     

Nationwide survey of hepatitis E virus infection among wildlife in Japan

In Japan, hepatitis E virus (HEV) causes hepatitis in humans through the consumption of raw or undercooked meat, including game meat. In the present study, nationwide surveillance of HEV infection among a total of 5,557 wild animals, including 15 species, was conducted in Japan. The prevalence of anti-HEV antibodies in wild boar was 12.4%, with higher positive rates in big boars (over 50 kg, 18.4%) than in small individuals (less than 30 kg, 5.3%). Furthermore, HEV RNA was more frequently detected in piglets than in older boars. Interestingly, the detection of HEV among wildlife by ELISA and RT-PCR suggested that HEV infection in Sika deer was a very rare event, and that there was no HEV infection among wild animals except for wild boar, Sika deer and Japanese monkeys. In conclusion, wild boar, especially piglets, are at high risk of HEV infection, while other wild animals showed less risk or no risk of HEV transmission.     

Correlation between villous height and the disaccharidase activity in the small intestine of piglets from nursing to growing

Early weaning induces villous atrophy in the small intestine. Reduction in villous height in the small intestine after weaning is associated with reductions in brush‐border enzyme activity. Body weight gain after weaning is, therefore, correlated with villous height. This evidence suggested that the maintenance of small intestinal structure and function after weaning is important for the growth of young pigs. On the other hand, the relationship between villous height and the activity of the digestive enzymes in the small intestine has not been studied with piglets from the suckling to the growing period. Five suckling piglets, four piglets in the proximal stage of weaning, four pigs in the distal stage of weaning and four growing pigs were used. The activities of lactase (LA), sucrase (SA) and maltase (MA) were determined. LA showed a positive correlation with villous height in weaning. SA and MA were positively correlated with villous height from suckling to growing. In a previous study, non‐infectious dyspeptic diarrhea was frequently observed in growing piglets on Japanese swine farms. The maintenance of villous height to retain disaccharidase activity may prevent dyspepsic diarrhea in this stage.     

Response of the carbon cycle in sub-arctic black spruce forests to climate change: Reduction of a carbon sink related to the sensitivity of heterotrophic respiration

Assessment of the response of the carbon cycle to climate change is important for predicting future climate, especially in northern high latitudes, where the warming may be highly pronounced. In this paper, three years of data measured by the eddy covariance method were used to verify the carbon dynamics of a black spruce forest in interior Alaska with the BIOME-BGC model. The model was modified and calibrated to the cold regions. The calibrated model simulation satisfactorily performed reproduction of the observed net ecosystem exchange (NEE), gross primary productivity (GPP), and ecosystem respiration (RE). The daily output of the model also correlated with field-based estimates of NEE (42%), GPP (89%), and RE (89%). The model simulation showed that the heterotrophic respiration occupied a substantial portion of total carbon exchange, and that inter-annual variation of the heterotrophic respiration determined the sink/source strength of carbon. According to our simulation, the black spruce forest in interior Alaska was a net carbon sink between 1949 and 2005, and the trend of the projected sink strength was not obvious in the recent climate warming. The model analysis suggested that the change in the seasonal weather pattern strongly affected the carbon balance. A potentially increased carbon sink due to future warming climate and elevated CO₂ will be at least partly offset by a concurrent increase of VPD, since the response of the stomatal conductance to increased VPD could increase the soil moisture, and thus stimulate heterotrophic respiration, rather than net primary productivity. The results of this study should be useful to forecast the response of the carbon cycle to warming in black spruce forests of interior Alaska.     

Evaluation of bone toxicity in various bones of aged rats

The aim of the present study was to provide a method for evaluating bone toxicity induced by drugs in various bones in aged rats. Male Crl:CD (SD) rats at 46 weeks of age were administered 15 mg/m(2) body surface area of doxorubicin, which effects the growth plate in weanling rats, weekly for 9 weeks by intravenous injection, and the femur, sternum, humerus and tibia were examined histopathologically. In the doxorubicin-treated group, thinning of the growth plate was remarkably observed in the proximal tibia and humerus; however, these changes were not observed in other regions. In addition, the osteoclast number per bone perimeter in the proximal tibia was significantly higher than others in control aged rat. Thus, recognizing the various histological reactions related to the time of epiphyseal closure is important for evaluating bone toxicity in aged rats.     

Inhibitory effects of oolong tea polyphenols on pancreatic lipase in vitro

Fifty-four polyphenols isolated from tea leaves were evaluated for their inhibitory activities against pancreatic lipase, the key enzyme of lipid absorption in the gut. (-)-Epigallocatechin 3-O-gallate (EGCG), which is one of major polyphenols in green tea, showed lipase inhibition with an IC50 of 0.349 microM. Moreover, flavan-3-ol digallate esters, such as (-)-epigallocatechin-3,5-digallate, showed higher activities of inhibition on lipase with an IC50 of 0.098 microM. On the other hand, nonesterified flavan-3-ols, such as (+)-catechin, (-)-epicatechin, (+)-gallocatechin, and (-)-epigallocatechin, showed zero and/or the lowest activities against pancreatic lipase (IC50 > 20 microM). These data suggested that the presence of galloyl moieties within the structure was required for enhancement of pancreatic lipase inhibition. It is well-known that flavan-3-ols are polymerized by polyphenol oxidase and/or heating in a manufacturing process of oolong tea. Oolonghomobisflavans A and B and oolongtheanin 3'-O-gallate, which are typical in oolong tea leaves, showed strong inhibitory activities with IC50 values of 0.048, 0.108, and 0.068 microM, respectively, even higher than that of EGCG. The oolong tea polymerized polyphenols (OTPP) were prepared for the assay from oolong tea extract, from which the preparation effectively subtracted the zero and/or less-active monomeric flavan-3-ols by preparative high-performance liquid chromatography. The weight-average molecular weight (Mw) and number-average molecular-weight (Mn) values of OTPP were 2017 and 903, respectively, by using gel permeation choromatography. OTPP showed a 5-fold stronger inhibition against pancreatic lipase (IC50 = 0.28 microg/mL) by comparison with that of the tannase-treated OTPP (IC50 = 1.38 microg/mL). These data suggested that the presence of galloyl moieties within their chemical structures and/or the polymerization of flavan-3-ols were required for enhancement of pancreatic lipase inhibition.