稻纵卷叶螟和白背飞虱序列危害及间隔天数对水稻生理生化的影响

【目的】为了解稻纵卷叶螟Cnaphalocrocis medinalis和白背飞虱Sogatella furcifera的复合危害对水稻产量相关因子和相关酶类的影响。【方法】本文设定两种害虫的先后危害顺序,并通过调整两者开始危害的时间,研究了受害后水稻在灌浆期根、茎和叶片中淀粉和蔗糖含量的变化以及蔗糖合成酶(Sucrose synthase,SS)和蔗糖磷酸合成酶(Sucrose phosphate synthase,SPS)活性的变化。【结果】随着接虫量的增加,水稻不同组织内各生理指标与对照相比均显著下降。随着间隔天数的增加,先接白背飞虱为害要重于先接稻纵卷叶螟。比如叶片中蔗糖含量在先接稻纵卷叶螟的处理中随着间隔天数的增加显著增加,相应的SPS活性显著增加,间隔24 d的处理显著高于间隔6 d和12 d;而先接白背飞虱的处理中蔗糖含量与SPS活性均显著降低,间隔24 d的处理显著低于间隔6 d和12 d的处理。茎部淀粉含量在先接稻纵卷叶螟的处理中随着间隔天数的增加逐渐增加,SS活性显著增加,而先接白背飞虱的处理中淀粉含量和SS活性均显著降低;叶片中淀粉含量均随着间隔天数的增加逐渐降低,而相应的SS活性在先接稻纵卷叶螟的处理中显著增加,在先接白背飞虱的处理中相反。另外,接虫量和间隔天数间有显著的交互作用。【结论】本研究对指导水稻生产中的"两迁害虫"防治具有潜在应用价值。     

崇明东滩盐沼植被扩散格局及其形成机制

长江河口盐沼植被的形成和演化是生物与其生长环境相互作用的结果。以崇明东滩盐沼植被典型扩散前沿为研究对象,2011至2012年期间调查了盐沼植被扩散前沿实生苗扩散、定居以及形成的扩散格局,同时测定了盐沼植被扩散前沿的潮滩冲淤动态和水文动力条件。研究结果表明,崇明东滩盐沼植被在扩散前沿形成了互花米草-光滩(Spartina alterniflora-Mudflat,SM)和互花米草-海三棱藨草-光滩(Spartina alterniflora-Scirpus mariqueter-Mudflat,SSM)两种典型的扩散格局。冲淤动态和水文动力条件是影响盐沼植被扩散格局的重要因子,尤其是在4—6月盐沼植物实生苗传播和定居的关键阶段。在此基础上,分析了东滩盐沼植被扩散前沿的生物-物理相互作用以及盐沼植被扩散格局的形成机制。研究结果不仅有助于理解长江河口地区盐沼植被扩散的生物物理过程,并对全球气候变化和海平面上升条件下滨海生态系统动态预测与湿地保护与管理具有重要的意义。     

印度南瓜果皮和果肉颜色遗传分析及基因定位

以印度南瓜‘98-2-351’与‘06820-1’杂交构建F2群体,对亲本及各世代群体成熟果实果皮和果肉颜色进行调查、统计分析。结果表明:F2群体中果皮桔红色和灰色的分离比呈3∶1,说明果皮灰色是由单隐性基因控制;F2群体中果肉黄色和白色的分离比呈3∶1,说明果肉白色也是由单隐性基因控制。利用群体分离分析法结合隐性群体分析法,采用SSR分子标记,找到了2个与控制灰色果皮基因位点CmRc紧密连锁的SSR标记(PU078072和PU013839),其连锁遗传距离分别为5.9cM和14.5cM;同时找到了1个与控制白色果肉基因位点CmFc紧密连锁的SSR标记PU132712,其连锁遗传距离为6.7cM。本研究为进一步筛选与控制印度南瓜果皮和果肉颜色基因更加紧密连锁的分子标记及相关基因的精确定位奠定了基础。     

Safety first: terrestrial predators drive selection of highly specific nesting sites in colonial‐breeding birds

Nesting is a critical yet hazardous life stage for many birds. For colonial‐breeding birds, the conspicuousness of the colony to predators suggests immense pressure to select optimal colonial nesting sites. But what drives selection of those sites? As with solitary nesting birds, reducing access by predators may be the single most important factor. If so, knowledge of the predators involved and the attributes of different potential colony sites can allow us to predict the features that make a site especially safe. We examined the attributes of trees used by breeding colonies of metallic starlings Aplonis metallica in tropical Australia, and experimentally tested if those attributes prevented nest access by predatory snakes. Our surveys confirmed that tree choice by starling nesting colonies is highly non‐random, with all colonies located in tall trees in rainforest clearings, with no low branches and smooth bark. Experimental tests demonstrated that the climbing ability of predatory snakes depends upon bark rugosity, and that colony access by snakes depends on tree attributes such as bark rugosity and canopy connectivity. Our study confirms that colonial‐nesting starlings select colony sites that provide a safe refuge from predation. Intense predation pressure may have driven the evolution of stringent breeding habitat criteria in many other species of colonial‐breeding birds.     

斜胸叶蝉属一新种（同翅目：叶蝉总科：耳叶蝉科）

本文记述耳叶蝉科斜胸叶蝉属一新种:黄缘斜胸叶蝉Epiclinata flavomarinata sp.nov.。标本采自我国西藏。文中描述了新种的外部形态及雄性外生殖器构造特征,并与近似种进行比较,附有主要特征图。模式标本保存于中国科学院动物研究所。     

Vanishing islands in the sky? A comparison of correlation- and mechanism-based forecasts of range dynamics for montane salamanders under climate change

Forecasting the effects of climate change on species and populations is a fundamental goal of conservation biology, especially for montane endemics which seemingly are under the greatest threat of extinction given their association with cool, high elevation habitats. Species distribution models (also known as niche models) predict where on the landscape there is suitable habitat for a species of interest. Correlative niche modeling, the most commonly employed approach to predict species' distributions, relies on correlations between species' localities and current environmental data. This type of model could spuriously forecast less future suitable habitat because species' current distributions may not adequately represent their thermal tolerance, and future climate conditions may not be analogous to current conditions. We compared the predicted distributions for three montane species of Plethodon salamanders in the southern Appalachian Mountains of North America using a correlative modeling approach and a mechanistic model. The mechanistic model incorporates species-specific physiology, morphology and behavior to predict an annual energy budget on the landscape. Both modeling approaches performed well at predicting the species' current distributions and predicted that all species could persist in habitats at higher elevation through 2085. The mechanistic model predicted more future suitable habitat than the correlative model. We attribute these differences to the mechanistic approach being able to model shifts in key range-limiting biological processes (changes in surface activity time and energy costs) that the correlative approach cannot. Choice of global circulation model (GCM) contributed significantly to distribution predictions, with a tenfold difference in future suitability based on GCM, indicating that GCM variability should be either directly included in models of species distributions or, indirectly, through the use of multi-model ensemble averages. Our results indicate that correlative models are over-predicting habitat loss for montane species, suggesting a critical need to incorporate mechanisms into forecasts of species' range dynamics.     

离子通道在肺动脉的分布及在低氧肺血管收缩反应中的作用

低氧性肺血管收缩反应（HPV）是指在急性低氧时,肺泡氧分压降到某一临界值,肺血管发生的快速、可逆的收缩反应,以纠正肺泡通气／灌流的不匹配。HPV的发生与肺动脉平滑肌细胞上K^＋、Ca^2＋、Cl^-通道的状态密切相关,而这些通道在不同部位的肺动脉上分布存在差异,因此不同部位的肺动脉在低氧中所表现的收缩反应程度也不同,本综述将对上述通道在肺动脉上的分布特点及其在HPV中的作用做一总结。     

Ceramide increases steroid hormone production in MA-10 Leydig cells.

Ceramide is known to have major roles in the control of cell proliferation, differentiation, and apoptosis. Recent studies also have shown that ceramide affects steroid production by JEG-3 choriocarcinoma cells, acutely dispersed rat Leydig cells, and ovarian granulosa cells, but the mechanism by which this occurs is unknown. Because ceramide induces apoptosis in many different cell types, we hypothesized that ceramide might affect steroidogenesis and/or induce apoptosis in MA-10 murine Leydig cells. To test this, MA-10 cells were incubated with either the water soluble C2-ceramide, (N-acetyl-sphingosine, 0.01-10 cm); bacterial sphingomyelinase (1-100 mU/ml); or C2-dihydroceramide (N-acetyl-sphinganine, 0.1-10 microM). The data show that N-acetyl-sphingosine significantly increased basal (0.87 +/- 0.2 vs. 0.42 +/- 0.09 ng/mg cell protein, P < 0.01) and human chorionic gonadotropin (hCG) stimulated progesterone (P) synthesis (204 +/- 12 vs. 120 +/- 5 ng/mg cell protein, P < 0.001); as did sphingomyelinase (basal P = 0.83 +/- 0.1 ng/mg cell protein, P < 0.01; hCG stimulated P = 173 +/- 7 ng/mg cell protein, P < 0.001). C2-dihydroceramide also increased basal P synthesis but was less effective than ceramide on a molar basis. Neither sphingomyelinase (100 mU/ml) nor ceramide (10 microM) had any effect on cAMP production or human chorionic gonadotropin binding; and neither induced any signs of apoptosis (FragEL DNA fragmentation assay and electron microscopy). Cells incubated with anti-Fas (300 ng/ml) demonstrated DNA fragmentation, nuclear condensation, and frequent apoptotic bodies, but had no change in P synthesis. These data show that ceramide significantly increases MA-10 Leydig cell P synthesis but does not induce apoptosis. The mechanism by which ceramide increases steroid hormone synthesis remains unknown but does not appear to be linked to the induction of apoptosis in MA-10 cells.     

BMP Signaling and Podocyte Markers Are Decreased in Human Diabetic Nephropathy in Association With CTGF Overexpression

Diabetic nephropathy is characterized by decreased expression of bone morphogenetic protein-7 (BMP-7) and decreased podocyte number and differentiation. Extracellular antagonists such as connective tissue growth factor (CTGF; CCN-2) and sclerostin domain-containing-1 (SOSTDC1; USAG-1) are important determinants of BMP signaling activity in glomeruli. We studied BMP signaling activity in glomeruli from diabetic patients and non-diabetic individuals and from control and diabetic CTGF^+/+ and CTGF^+/− mice. BMP signaling activity was visualized by phosphorylated Smad1, -5, and -8 (pSmad1/5/8) immunostaining, and related to expression of CTGF, SOSTDC1, and the podocyte differentiation markers WT1, synaptopodin, and nephrin. In control and diabetic glomeruli, pSmad1/5/8 was mainly localized in podocytes, but both number of positive cells and staining intensity were decreased in diabetes. Nephrin and synaptopodin were decreased in diabetic glomeruli. Decrease of pSmad1/5/8 was only partially explained by decrease in podocyte number. SOSTDC1 and CTGF were expressed exclusively in podocytes. In diabetic glomeruli, SOSTDC1 decreased in parallel with podocyte number, whereas CTGF was strongly increased. In diabetic CTGF^+/− mice, pSmad1/5/8 was preserved, compared with diabetic CTGF^+/+ mice. In conclusion, in human diabetic nephropathy, BMP signaling activity is diminished, together with reduction of podocyte markers. This might relate to concomitant overexpression of CTGF but not SOSTDC1. (J Histochem Cytochem 57:623–631, 2009)     

Response of carbon fluxes to drought in a coastal plain loblolly pine forest

Full accounting of ecosystem carbon (C) pools and fluxes in coastal plain ecosystems remains less studied compared with upland systems, even though the C stocks in these systems may be up to an order of magnitude higher, making them a potentially important component in regional C cycle. Here, we report C pools and CO₂ exchange rates during three hydrologically contrasting years (i.e. 2005–2007) in a coastal plain loblolly pine plantation in North Carolina, USA. The daily temperatures were similar among the study years and to the long‐term (1971–2000) average, whereas the amount and timing of precipitation differed significantly. Precipitation was the largest in 2005 (147 mm above normal), intermediate in 2006 (48 mm below) and lowest in 2007 (486 mm below normal). The forest was a strong C sink during all years, sequestering 361 ± 67 (2005), 835 ± 55 (2006) and 724 ± 55 (2007) g C m^?2 yr^?1 according to eddy covariance measurements of net ecosystem CO₂ exchange (NEE). The interannual differences in NEE were traced to drought‐induced declines in canopy and whole tree hydraulic conductances, which declined with growing precipitation deficit and decreasing soil volumetric water content (VWC). In contrast, the interannual differences were small in gross ecosystem productivity (GEP) and ecosystem respiration (ER), both seemingly insensitive to drought. However, the drought sensitivity of GEP was masked by higher leaf area index and higher photosynthetically active radiation during the dry year. Normalizing GEP by these factors enhanced interannual differences, but there were no signs of suppressed GEP at low VWC during any given year. Although ER was very consistent across the 3 years, and not suppressed by low VWC, the total respiratory cost as a fraction of net primary production increased with annual precipitation and the contribution of heterotrophic respiration (R_h) was significantly higher during the wettest year, exceeding new litter inputs by 58%. Although the difference was smaller during the other 2 years (R_h : litterfall ratio was 1.05 in 2006 and 1.10 in 2007), the soils lost about 109 g C m^?2 yr^?1, outlining their potential vulnerability to decomposition, and pointing to potential management considerations to protect existing soil C stocks.