[Moderate grazing increases the abundance of soil methane-oxidizing bacteria and CH4 uptake rate in a typical steppe of Inner Mongolia, China.] / é€‚åº¦æ”¾ç‰§å¢žåŠ å† è’™å¤å ¸åž‹è‰åŽŸç”²çƒ·æ°§åŒ–èŒä¸°åº¦å’Œç”²çƒ·å¸æ”¶.

Microbial oxidation is the only biological sink of atmospheric methane (CH4). It is essential to understand the variation of CH4 fluxes among different grassland use types for developing low-emission management system. Here, we measured the CH4 flux and the soil methane-oxidizing bacteria abundance in a typical steppe under grazing, mowing and fencing management in central Inner Mongolia, with the aims to determine the effects of these grassland use types on CH4 flux, and to test the hypothesis that pmoA functional gene abundance regulates CH4 fluxes. The measurements were conducted on the experimental grassland that had experienced four grassland use treatments over five years. The treatments were whole growing season grazing from May to September (T1), spring and summer grazing (twice in May and July)(T2), autumn mowing (T3) and enclosure (T0). We measured CH4 flux using static chamber method, and quantified the abundance of pmoA functional genes using molecular techniques. Moreover, we measured plant biomass and soil physicochemical properties. The results showed that moderate grazing significantly enhanced CH4 uptake rate and the methane-oxidizing bacteria abundance (i.e., the pmoA gene copy number per gram of dry soil). The pmoA gene copy number ranged from 6.9×104 to 3.9×105 per gram of dry soil in growing season. The CH4 uptake rate was (68.21±3.01) µg·m-2·h-1 under T1, which was 22.1%, 37.5% and 30.9% higher than that under T2, T3 or T0 , respectively. The CH4 uptake rate was positively correlated with abundance of CH4 oxidizing bacteria and soil sand content, but negatively correlated with soil silt content, soil moisture, NH4+-N and NO3--N content, and plant biomass. These results suggested that the steppe ecosystem is a CH4 sink under all land-use types in central Inner Mongolia, and that moderate grazing would enhance methane-oxidizing bacteria abundance and CH4 uptake by improving soil sand content, reducing soil mineral nitrogen content and plant production in the typical steppe ecosystem. These results were of significance for the development of low-emission grassland management system.

[Effects of grazing and mowing on macrofauna communities in a typical steppe of Inner Mongolia, China]. / æ”¾ç‰§å’Œåˆˆå‰²å¯¹å† è’™å¤å ¸åž‹è‰åŽŸå¤§åž‹åœŸå£¤åŠ¨ç‰©çš„å½±å“.

The dynamic features of the ecosystem components under different human activities are fundamental for understanding the ecosystem change mechanisms and developing sustainable mana-gement system. For the vast temperate steppe ecosystems in northern China, there existed many studies on the effects of animal grazing and mowing on plant and soil microbial communities, but not the soil fauna communities. We investigated the soil macrofauna communities of a typical Inner Mongolia steppe grassland under 6 utilization treatments (1 full season grazing, 3 different seasonal grazing, 1 autumn mowing and 1 control of no grazing or mowing). The investigation was conducted in spring, summer and autumn after 3-year's grazing or mowing treatments. We collected 597 soil animals, which belonged to 2 phyla, 4 orders, 11 classes, and 49 groups. The individual density, biomass and diversity indices of soil macrofauna community significantly decreased under the full season grazing, whereas the effects of mowing on soil macrofauna were relatively mild, with the individual density, biomass and diversity indices of soil macrofauna community even showing an increasing trend. The seasonal grazing in summer and autumn had the least negative effects on the individual density, biomass and diversity indices of soil macrofauna community among three seasonal grazing treatments. The results suggested that mowing might facilitate the restoration of soil macrofauna community for degraded steppe grassland, and the seasonal grazing in summer and autumn had the least negative effects on soil macrofauna communities, which was possibly the best grazing practice for a sustainable grassland use.

Effect of transarterial pulsed perfusion with heated saline on tumor vascular permeability in a rabbit VX2 liver tumor model.

PURPOSE: To evaluate the effect of transarterial pulsed perfusion with 60 °C saline on vascular permeability of tumor tissue, as well as its hepatic and renal toxicity, in a rabbit VX2 liver model. MATERIALS AND METHODS: VX2 carcinomas were grown in rabbit livers, forty male New Zealand white tumor-bearing rabbits were randomly divided into four groups, followed by transarterial perfusion with 37 °C saline 60 ml (n=10) (control 1 group), transarterial pulsed perfusion with 37 °C saline 60 ml (n=10) (control 2 group), transarterial continuous perfusion with 60 °C saline 60 ml (n=10) (TCP group), transarterial pulsed perfusion with 60 °C saline 60 ml (n=10) (TPP group), the duration of time for tumor tissues in the range 43-45 °C of the treated groups was measured with needle thermometer during perfusion. Vascular permeability was assessed using the extravasation of Evans blue (EB) dye in the tumor or normal liver tissues of the four groups separately, the tumor or normal liver tissues of the four groups were estimated by histopathologic examination, and hepatic and renal toxicity was evaluated by means of blood biochemical analysis. The vascular endothelial cells in the tumor were observed by transmission electron microscopy (TEM). RESULTS: The duration of time for tumor tissues in the range 43-45 °C of TPP group showed significantly longer than that of TCP group (12.3±3.3 min vs. 5.7±2.5 min) (P<0.01). After perfusion, the EB content of tumor tissue in TPP group showed significantly higher than that in TCP group (15.21±0.94 µg/100 mg vs. 10.71±0.84 µg/100 mg) (P<0.01), and also showed significantly higher than that in the two control group (3.42±0.87 µg/100 mg, 3.57±0.64 µg/100 mg) (P<0.01). Blood chemical analysis indicating there was an increase (P<0.05) in the serum ALT, AST levels in the two heated perfusion groups at 1, 2, 4, 8 h after infusion when compared to that in the two control group, but there was no significant difference in the serum ALT, AST levels among the four groups at 24 h after perfusion (P>0.05), and there was no significant difference in the serum BUN, Cr levels among the four groups at 1, 2, 4, 8, 24 h after perfusion. Observed by hematoxylin and eosin staining, there were no obvious signs of tissue destruction in liver tissue and tumor tissue. TEM indicating the endothelial cell gap was broadened and the endothelial cells' microvillus was decreased after heated perfusion. CONCLUSIONS: The vascular permeability of the rabbit VX2 tumor was significantly increased after transarterial pulsed perfusion with 60°C saline without significant increase in hepatic and renal toxicity.

Study on spatial-temporal variation of infected snail in bottomland areas after an integrated control strategy at village level in the marshland and lake regions based on geographic information system / 中华流行病学杂志

Objective To evaluate the effect of an integrated control strategy and to quantify the spatial-temporal variation of infected snails in the bottomland areas after the strategy was implemented.Methods Based on the geographic database of infected snail distribution at the village level during 2004-2010 in Anxiang county,Hunan province,spatial autocorrelation analysis and spatial scan statistics were applied to analyze the spatial-temporal characteristics on the distribution of infected snails.Results The number of embankments with infected snails in Anxiang county decreased from 23 in 2004 to 10 in 2010,while the rate of frame with infected snail in embankments decreased from 4.32‰ in 2004 to 0.12‰ in 2010.The spatial distribution of infected snails was nonrandom,only in 2004 and 2005 with Moran's I=0.21 (P＜0.10) and Moran's I=0.13 (P＜0.10) respectively.Data from the local spatial auto-correlation analysis showed that the number of villages with H-H types of auto-correlation model had been gradually decreasing.The results of SaTScan statistics appeared the same as from the local spatial auto-correlation analysis,showing that the number of areas with increased risk was decreasing.Conclusion The comprehensive measures with emphasis on infectious source control seemed effective for schistosomiasis control program.The current distribution characteristics provided us with evidence that the resource assignment could be more reasonably implemented so as to control schistosomiasis in a more effective way.

[Evaluation of schistosomiasis control effect of buffalo removal in Anxiang County].

OBJECTIVE: To evaluate the effect of a comprehensive schistosomiasis control strategy based on buffalo removal in a lake and marshland region. METHODS: A community intervention trial was carried out in seven pilot villages and seven control villages along Dongting Lake in Anxiang County, Hunan Province. Besides annual routine control measures such as synchronous chemotherapy, molluscicidal spray and health education, all buffaloes and sheep were killed or removed from the pilot areas in 2005, of which the effect was strengthened by other supporting measures such as replacing bovines by agricultural machines, isolating meadows and prohibiting pastures, supplying safe water, and building sanitary lavatories or methane pits. Schistosoma japonicum infection in humans or Oncomelania snails was observed and followed up to the spring of 2011. RESULTS: Three years after the intervention, the infection rates in humans decreased to below 1% with no infected snails found outside the embankment in the pilot villages, but the infection rates still ranged between 2% and 3% in the control villages 4 years after the intervention. The comprehensive measures centered on buffalo removal exempted about 50% of the population from the infection in pilot villages. CONCLUSION: Buffalo removal is the key element of comprehensive control strategy which could accelerate the control process and promote the elimination of schistosomiasis in lake and marshland regions along the Yangtze River.