Karyotype analysis of four nemertean species

We performed a karyotype analysis on four species from Phylum Nemertea using regenerating somatic cells. Two palaeonemertean species, Cephalothrix hongkongiensis and Cephalothrix sp., had the same chromosome number (2n=28), but different karyotypes (16 m+10 sm+2 st, NF=54 and 22 m+4 sm+2 st, NF=54, respectively). The karyotypes of the two heteronemerteans, Notospermus geniculatus and Ramphogordius sanguineus were 2n=38, 30 m+6 sm+2 sm/st (NF=76/74) and 2n=56, 48 m+4 sm+4 sm/st (NF=112/108), respectively.     

Distribution patterns of chlorophyll <Emphasis Type="Italic">a</Emphasis> in spring and autumn in association with hydrological features in the southern Yellow Sea and northern East China Sea

Two field studies were conducted to measure pigments in the Southern Yellow Sea (SYS) and the northern East China Sea (NECS) in April (spring) and September (autumn) to evaluate the distribution pattern of phytoplankton stock (Chl a concentration) and the impact of hydrological features such as water mass, mixing and tidal front on these patterns. The results indicated that the Chl a concentration was 2.43±2.64 (Mean ± SD) mg m^?3 in April (range, 0.35 to 17.02 mg m^?3) and 1.75±3.10 mg m^?3 in September (from 0.07 to 36.54 mg m^?3) in 2003. Additionally, four areas with higher Chl a concentrations were observed in the surface water in April, while two were observed in September, and these areas were located within or near the point at which different water masses converged (temperature front area). The distribution pattern of Chl a was generally consistent between onshore and offshore stations at different depths in April and September. Specifically, higher Chl a concentrations were observed along the coastal line in September, which consisted of a mixing area and a tidal front area, although the distributional pattern of Chl a concentrations varied along transects in April. The maximum Chl a concentration at each station was observed in the surface and subsurface layer (0–10 m) for onshore stations and the thermocline layer (10–30 m) for offshore stations in September, while the greatest concentrations were generally observed in surface and subsurface water (0–10 m) in April. The formation of the Chl a distributional pattern in the SYS and NECS and its relationship with possible influencing factors is also discussed. Although physical forces had a close relationship with Chl a distribution, more data are required to clearly and comprehensively elucidate the spatial pattern dynamics of Chl a in the SYS and NECS.     

Antiangiogenic activity of low-temperature lysozyme from a marine bacterium <Emphasis Type="Italic">in vivo</Emphasis> and <Emphasis Type="Italic">in vitro</Emphasis>

We extracted marine low-temperature lysozyme (MLTL), a novel lysozyme, from a marine microorganism through fermentation. Our previous study suggested that a low molecular weight (16 kDa) may exert anti-tumor activity through antiangiogenesis. In this study, we extracted a high weight (39 kDa) and investigated its antiangiogenic activity in vivo and in vitro. Using zebrafish embryos as an in vivo study model, we found that treatment with MLTL significantly inhibited the growth of subintestinal vessels (SIVs) in a dose-dependent manner and that 400 μg/ml MLTL was sufficient to block the growth of SIVs. An in vitro study conducted using human umbilical vein endothelial cells (HUVECs) revealed that MLTL suppressed the proliferation, migration and tube formation of HUVECs in a dose-dependent manner. Interestingly, assays by flow cytometry and DNA electrophoresis indicated that MLTL was able to induce apoptosis of HUVECs. Moreover, further study demonstrated that the disruption of intracellular Ca²⁺ homeostasis may play an important role in MLTL induced apoptosis of HUVECs. Taken together, the results of this study demonstrate for the first time that MLTL inhibits angiogenesis through its pleiotropic effects on vascular endothelial cells and induces apoptosis through regulation of cellular Ca²⁺ levels. The results of this study also revealed a possible mechanism underlying the antiangiogenic effect of MLTL and suggested that MLTL may be a promising new antiangiogenic agent for use in cancer therapy.     

Livelihood strategy change and land use change —Case of Danzam Village in upper Dadu River watershed, Tibetan Plateau of China

Land use change in rural China since the 1980s, induced by institution reforms, urbanization, industrialization and population increase, has received more attention. However, case studies on how institution reforms affect farmers’ livelihood strategies and drive land use change are scarce. By means of cropland plots investigations and interviews with farmers, this study examines livelihood strategy change and land use change in Danzam Village of Jinchuan County in the upper Dadu River watershed, eastern Tibetan Plateau, China. The results show that, during the collective system period, as surplus labor forces could not be transferred to the secondary and tertiary industries, they had to choose agricultural involution as their livelihood strategy, then the farmers had to produce more grains by land reclamation, increasing multiple cropping index, improving input of labor, fertilizer, pesticide and adopting advanced agricultural techniques. During the household responsibility system period, as labors being transferred to the secondary and tertiary industries, farmers chose livelihood diversification strategy. Therefore, labor input to grain planting was greatly reduced, which drove the transformation of grain to horticulture, vegetable or wasteland and decrease of multiple cropping index. This study provides a new insight into understanding linkages among institution reforms, livelihood strategy of smallholders and land use change in rural China. Foundation item: Under the auspices of National Natural Science Foundation of China (No. 40601006, 40471009), National Basic Research Program of China (No. 2005CB422006)     

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Impact factors on distribution and characteristics of natural plant community in reclamation zones of Changjiang River estuary

To identify impact factors on the distribution and characters of natural plants community in reclamation area, with survey data from 67 plant quadrats in July 2009, soil properties data from 216 sampling points in April 2009, and TM (30 m) data in 2006, the composition and characteristics of natural plants community in different time of the Fengxian area in the Changjiang (Yangtze) River estuary were analyzed with two-way indicator species analysis (TWINSPAN), multivariate analysis of variance (MANOVA), detrended canonical correspondence analysis (DCCA) and canonical correspondence analysis (CCA). The results show that: 1) The plant communities in the reclaimed area are mainly mesophytes and helophytic-mesophytic transitional communities, showing a gradient distribution trend with the change in reclamation years. Species richness (MA), species diversity (H) and above-ground biomass also increase with the increase of reclamation years. Nevertheless, they appear to decline slightly in the middle and late reclamation period (> 30 years). 2) With the rise in land use levels, the changes in species richness and species diversity tend to increase at first and then decrease; species dominance (D), however, tends to decline; and above-ground biomass increases slightly. 3) The distribution of the plant community is mainly influenced by the following factors: land use levels (R = 0.55, p < 0.05), soil moisture (R = 0.53, p < 0.05), soil salinity (R = 0.43, p < 0.05) and reclamation time (R = 0.40, p < 0.05).     

Runoff change of Naoli River in Northeast China in 1955–2009 and its influencing factors

Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 for Bao′an station, from 1955 to 2009 for Baoqing station, from 1956 to 2009 for Caizuizi station and from 1978 to 2009 for Hongqiling station. The influences of climate change and human activities on runoff change were investigated, and the causes of hydrological regime change were revealed. The seasonal runoff distribution of the Naoli River was extremely uneven, and the annual change was great. Overall, the annual runoff showed a significant decreasing trend. The annual runoff of Bao′an, Baoqing, and Caizuizi stations in 2009 decreased by 64.1%, 76.3%, and 84.3%, respectively, compared with their beginning data recorded. The wet and dry years of the Naoli River have changed in the study period. The frequency of wet year occurrence decreased and lasted longer, whereas that of dry year occurrence increased. The frequency of dry year occurrence increased from 25.0%-27.8% to 83.9%-87.5%. The years before the 1970s were mostly wet, whereas those after the 1970s were mostly dry. Precipitation reduction and land use changes contributed to the decrease in annual runoff. Rising temperature and water project construction have also contributed important effects on the runoff change of the Naoli River.     

广西小平阳岩溶区地裂缝形成因素分析

８０年代以来，广西小平阳岩溶区出现了大量的地裂缝。通过调查研究．这些地裂缝的形成是受多种因素控制的．其中包括构造、土体性质、水的作用、地形地貌、气候及植被等因素。在上述因素中．构造是主导因素，上体性质是基础因素．其它则为诱发因素，也是因地质环境要素变化所引起的因素。主导因素是通过诱发因素起作用的．并最终通过土体性质因素导致产土地裂缝。