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This study aimed to investigate the effect of silage or dry cornstalk diets on methane emission, rumen fermentation, and methanogenic community, and reveal whether the change of methanogenic compositions was related to the methane production. A total of 39 sheep were divided into four groups, fed diets of different concentrate level based on silage or dry cornstalk roughage for 40 days. It was found that, at 20% concentrate level, the sheep fed silage could suppress methanogenesis significantly in contrast with the silage diet ( p < 0.05). The ruminal acetate:propionate ratio was 3.17 in the silage-fed sheep significantly lower than 3.78 in the dry cornstalk-fed sheep ( p < 0.05), reflecting the effect of fermentation on methane output was related to roughage types. Furthermore, the methanogens was found to be significantly lower abundance ( p < 0.05), and showed a different pattern using multivariate statistical analysis in silage-fed sheep. Compared with dry cornstalk diet, silage diet of 20% concentrate reduced methane production, decreased methanogenic abundance, and induced change of Methanobrevibacter composition at strain levels. This study showed variation of methanogenic compositions at strain level and its probable relationship with methane production, and provided microbial information to explain the low methane output when the animals were fed silage. [ABSTRACT FROM AUTHOR]

Accurate measurement of soil total N (TN) content in agricultural fields is important to guide reasonable application of nitrogenous fertilizer. Estimation of soil TN content with limited in situ data at an acceptable level of accuracy is important because laboratory measurement of N is a time-and labor-consuming procedure. This study was conducted to evaluate cokriging of soil TN with predicted soil organic matter (SOM) content as auxiliary data. The SOM content was predicted by cokriging with a digital number (DN) of Band 1 of Landsat Enhanced Thematic Mapper (ETM) imagery. Soil TN content was estimated by using 88 soil samples for prediction and 43 soil samples for validation in a study area of 367 km2 in Haining City, China. Field-measured soil TN content ranged from 0.47 to 2.48 g kg-1, with a mean of 1.25 g kg-1. Soil TN content of all 131 soil samples including samples for prediction and validation was highly correlated with measured (r = 0.81, p < 0.01) and predicted (r = 0.81, p < 0.01) SOM content in paddy fields. Then, the predicted SOM content was used as auxiliary variable for the prediction of soil TN content. By using the 43 samples for validation, we had a mean error (ME) of 0.03 g kg-1 and a root mean square error (RMSE) of 0.31 g kg-1 for kriging, and a mean error of 0.00 g kg-1 and a root mean square error of 0.25 g kg-1 for cokriging, respectively. Our results indicate cokriging with predicted SOM content data was superior to kriging. In addition, predicted data of the auxiliary variable have the potential to be useful for cokriging when the predicted auxiliary data have high prediction accuracy. [ABSTRACT FROM AUTHOR]

Accurately measuring soil organic matter content (SOM) in paddy fields is important because SOM is one of the key soil properties controlling nutrient budgets in agricultural production systems. Estimation of this soil property at an acceptable level of accuracy is important; especially in the case when SOM exhibits strong spatial dependence and its measurement is a time- and labor-consuming procedure. This study was conducted to evaluate and compare spatial estimation by kriging and cokriging with remotely sensed data to predict SOM using limited available data for a 367-km² study area in Haining City, Zhejiang Province, China. Measured SOM ranged from 5.7 to 40.4 g kg-1, with a mean of 19.5 g kg-1. Correlation analysis between the SOM content of 131 soil samples and the corresponding digital number (DN) of six bands (Band 1-5 and Band 7) of Landsat Enhanced Thematic Mapper (ETM) imagery showed that correlation between SOM and DN of Band 1 was the highest (r = -0.5 87). We used the DN of Band 1 as auxiliary data for the SOM prediction, and used descriptive statistics and the kriging standard deviation (STD) to compare the reliabilities of the predictions. We also used cross-validation to validate the SOM prediction. Results indicate that cokriging with remotely sensed data was superior to kriging in the case of limited available data and the moderately strong linear relationship between remotely sensed data and SOM content. Remotely sensed data such as Landsat ETM imagery have the potential as useful auxiliary variables for improving the precision and reliability of SOM prediction. [ABSTRACT FROM AUTHOR]

The article discusses research that applied a regression model to predict the average cadmium content in rice grains for paddy fields located in China's Zhejiang province. Soils in the Fuyang valley have been contaminated by heavy metals. Cadmium has a tendency to bioaccumulate in rice grains, posing a potential human health risk. A multiple linear model for assessing cadmium content is the most effective predictor, as it examines the sensitivity of calcium chloride-extracted cadmium for changes in oxidation-reduction potential.

From the aerial parts of Schisandra rubrifloraFranchRehd. et Wils., four new dibenzocyclooctadiene lignans, methylgomisin R 1, +14tigloylgomisin K32, 12demethylwuweilignan I 3, schisandrene A 4, together with 13known lignans, were isolated. The structures of four new compounds were elucidated by spectroscopic methods including extensive 1D and 2DNMR techniques. [ABSTRACT FROM AUTHOR]

Organochlorine pesticides were used extensively in the Yangtze River Delta, China. However, knowledge about their residual levels and environmental fates in soils of this area is limited. This paper presents the residue isomers and spatial pattern of dichlorodiphenyltrichloroethane (DDT) in soils across 17 main cities in the Yangtze River Delta. Forty-three soil surface (0-15 cm) samples were collected during a field campaign conducted in October 2003 in the Delta. Six DDT isomers (1-[2-chlorophenyl]- 1-[4-chlorophenyl]-2,2-dichloroethane [o,p'-DDD], 1-[2-chlorophenyl]-1-[4-chlorophenyl]-2,2-dichloroethylene [o,p-'DDE], 1,1,1- trichloro-2-[p-chlorophenyl]-2-[o-chlorophenyl]ethane [o,p'-DDT], p,p'-dichlorodiphenyldichloroethane [p,p'-DDD], p,p'-dichlorodiphenyldichloroethylene [p,p'-DDE], p,p'-dichlorodiphenyltrichloroethane [p,p'-DDT]) were detected using gas chromatography. The results show that p,p'-DDE was the dominant isomer in the soil samples. The levels of DDT are generally low in soils of this area and are comparable to DDT levels in other cities in China and in soils from developed countries such as the United States and Germany. The isomer ratios of o,p'-DDT to p,p'-DDT and DDT to (DDD + DDE) were employed to identify the source of DDT. The computed ratios implied that the source of DDT might be related to the application of dicofol, an acaricide manufactured from technical DDTs and mainly used on cotton fields to treat mites. [ABSTRACT FROM AUTHOR]

The protective effects of sasanquasaponin, an effective compound from Chinese traditional herbs, on ischaemia and reperfusion injury in mouse hearts have been suggested through modulation of intracellular Cl− homeostasis. The effects of sasanquasaponin on injury of endothelial cells, however, induced by anoxia and reoxygenation remain unknown. Therefore, the present study attempted to observe the effects of sasanquasaponin on anoxia and reoxygenation injury in endothelial cells and investigate its putative mechanisms. Human umbilical vein endothelial cells (HUVECs) were exposed to normoxia or anoxia and reoxygenation in the absence or presence of sasanquasaponin (10.0, 1.0 and 0.1 µmol/l). Lactate dehydrogenase activity was determined in cultured HUVECs supernatant, and malondialdehyde content, superoxide dismutase and glutathione peroxidase activities were measured in HUVECs by a colorimetric method. Neutrophil adhesion to HUVECs was assayed colorimetrically. The levels of intercellular adhesion molecule-1 and tumour necrosis factor-α were detected. The activity of nuclear factor kappa B was determined by flow cytometry. The results show that sasanquasaponin decreased the lactate dehydrogenase activity and malondialdehyde contents, and inhibited the neutrophil adhesion to HUVECs; sasanquasaponin, moreover, inhibited nuclear factor kappa B transnuclear activity, lowered tumour necrosis factor-α and intercellular adhesion molecule-1 expression levels. On the other hand, sasanquasaponin increased the mitochondrial superoxide dismutase and glutathione peroxidase activities. It is suggested that sasanquasaponin could protect HUVECs against anoxia and reoxygenation injury, and the protective mechanisms appear to be related to anti-lipoperoxidation and anti-adhesion. [ABSTRACT FROM AUTHOR]

Reports on a study of the anaerobic phosphate flux and mineralization of lake sediment organic carbon over a period of 182 days. Importance of lake sediment porewater composition and redox status that control material exchange at the sediment-water interface; Indication that under anaerobic conditions, organic-rich lake sediment can be an important source of phosphorus and methane.