Increased insulin sensitivity and obesity resistance in mice lacking the protein tyrosine phosphatase-1B gene

Protein tyrosine phosphatase-1B (PTP-1B) has been implicated in the negative regulation of insulin signaling. Disruption of the mouse homolog of the gene encoding PTP-1B yielded healthy mice that, in the fed state, had blood glucose concentrations that were slightly lower and concentrations of circulating insulin that were one-half those of their PTP-1B+/+ littermates. The enhanced insulin sensitivity of the PTP-1B-/- mice was also evident in glucose and insulin tolerance tests. The PTP-1B-/- mice showed increased phosphorylation of the insulin receptor in liver and muscle tissue after insulin injection in comparison to PTP-1B+/+ mice. On a high-fat diet, the PTP-1B-/- and PTP-1B+/- mice were resistant to weight gain and remained insulin sensitive, whereas the PTP-1B+/+ mice rapidly gained weight and became insulin resistant. These results demonstrate that PTP-1B has a major role in modulating both insulin sensitivity and fuel metabolism, thereby establishing it as a potential therapeutic target in the treatment of type 2 diabetes and obesity.     

Equine bullous pemphigoid IgG autoantibodies target linear epitopes in the NC16A ectodomain of collagen XVII (BP180, BPAG2)

Bullous pemphigoid (BP) is an autoimmune subepithelial blistering dermatosis of humans, dogs, cats and pigs. It is characterized by skin-fixed and circulating IgG autoantibodies that target one or both BP antigens. An immunological homologue of BP in humans was diagnosed in two horses with cutaneous and mucosal ulcerations as well as microscopic subepithelial vesiculation. Immunological investigations revealed similar findings for both the horses. Direct immunofluorescence demonstrated the presence of IgG deposited linearly at the dermoepidermal junction in mucosal and skin biopsy specimens. Indirect immunofluorescence testing confirmed the existence of circulating basement membrane-specific IgG autoantibodies. Using intact and salt-split epithelial substrates, serum IgG were shown to target antigens situated not only at the basal, but also at the lateral and apical aspects of stratum basale keratinocytes. Immunoblotting and ELISA corroborated that the IgG from affected horses, but not those from normal controls, exhibited high immunoreactivity against the NC16A extracellular domain of type XVII collagen (BPAG2, BP180). Equine BP could be proposed, therefore, as another spontaneous model of this most common basement membrane autoimmune dermatosis of humans.     

啤酒营养与保健作用的研究进展

啤酒是以大麦芽、啤酒花、酵母等原料酿造而成的一种低酒度(3%)饮品。啤酒营养丰富,含多种人体必需氨基酸、维生素和微量元素,以及生物活性物质,如多酚和黄酮类化合物等,饮用后对人体的多种生理功能具有调节作用。其药理和保健作用有:防止动脉硬化和心脏病、抑制癌症、促进血液循环、改善免疫机能、抗氧化与抗衰老、促进雌激素分泌、减轻放射线损害、预防白内障、解除肾结石、镇静、活化胃、促进食欲等。     

Effects of land ownership and landscape-level factors on rare-species richness in natural areas of southern Ontario,Canada

Surprisingly few studies have considered the extent to which the nature of the ownership of land is associated with differences in biodiversity. We analysed ownership and other landscape-level effects on rare-species richness for both globally- and regionally-rare biota (including birds, herpetofauna, butterflies, mammals, and plants) in 289 designated natural areas (NAs) in southern Ontario, Canada. Information about each NA −including area, number of plant communities, ownership status and details of species diversity were collected from published sources. Length of perimeter of NA, relative isolation, and an estimate of fragmentation were measured using image analysis and GIS techniques. NAs were in general relatively small, with mean area of 158 ha (median 85 ha, range from 0.9 to 1278 ha) for private NAs; public NAs had mean area of 132 ha (median 16 ha, range from 0.1 to 1481 ha). Mean number of plant communities was 4.6 (median 4, range 1- 13) at private NAs and 3.8 (median 3, range 1-16) at public NAs. Our results show that, of several landscape-level factors, area had the greatest effects on rare-species richness and other biotic indices. Effects of area were followed by effects of plant community diversity, however this was itself significantly affected by area and the extent of perimeter of the NA. Both these factors were followed by effects of ownership of the NA and by effects of isolation of the NA (represented by minimum distance to nearest NA and by number of NAs in 10 km radius). Other landscape- level factors did not appear to have overall significant effects. Variation in area accounted for 0.1% to 29% of variation in number of rare species, with lower values for globally-rare, than for regionally-rare taxa. For all biotic groups, public ownership of NAs was associated with significantly greater rare-species richness compared to private ownership, even after other factors such as area were controlled. For all globally-rare biota except butterflies, area of NA had greater effects on rare-species richness than did ownership. Richness of regionally- rare birds was more affected by plant community diversity than by area of NA. Number of recorded plant communities accounted from 2.1% of variation in number of globally-rare plant species to as high as 31% of variation in regionally-rare butterflies. The diversity of plant communities was itself influenced by total site area (accounting for 45% of variation), extent of elongation of the NA, and both external- and interior- edge perimeters. Public NAs had greatest numbers of rare biota and so should be a significant focus for conservation programs. Smaller, privately-owned patches of natural area dominate (by number and area) in this densely populated region and their significance should not be overlooked. This revised version was published online in July 2006 with corrections to the Cover Date.     

森林经营方案编制及实施效果评价的微机辅助系统研究

本文以微型计算机为工具，选用ｄＢＡＳＥⅢ关系型数据库和ＢＡＳＩＣＡ语言，研制了国营林场森林经营方案编制及实施效果评价的辅助系统，并以福建林学院莘口教学林场的森林资源数据试运行．经过运行表明，该系统结构合理、功能较全、性能可靠、科学实用．     

Emergence of anoxia in the California current large marine ecosystem

Eastern boundary current systems are among the world's most productive large marine ecosystems. Because upwelling currents transport nutrient-rich but oxygen-depleted water onto shallow seas, large expanses of productive continental shelves can be vulnerable to the risk of extreme low-oxygen events. Here, we report the novel rise of water-column shelf anoxia in the northern California Current system, a large marine ecosystem with no previous record of such extreme oxygen deficits. The expansion of anoxia highlights the potential for rapid and discontinuous ecosystem change in productive coastal systems that sustain a major portion of the world's fisheries.     

盐碱胁迫下羊草种子的萌发特性

时羊草Leymus chinensis种子在NaCl,Na2CO3和混合盐胁迫下的发芽率进行测定.在NaCl 12.5～600mmol/L,Na2CO312.5～150 mmol/L和混合盐37.5～250 mmol/L条件下羊草的发芽率均高于对照,在NaCl,Na2CO3浓度为1 2.5 mmol/L,混合盐75 mmol/L时发芽率最高,并且NaCl胁迫下的发芽率高于Na2CO3和混合盐,表明适宜的盐碱能促进种子发芽,中性盐更有助于促进种子发芽.方差分析表明羊草种子在3种胁迫下的发芽响应已产生分化,发芽率的变异系数为64.190 5%～66.625 5%.在不同环境条件下,羊草种子具有生态可塑性.     

青杄功能性状及其在各器官间分配格局的时空变化

为研究青杄在不同环境和发育阶段的适应性和生存策略,以关帝山典型森林分布区的青杄(Piceawilsonii)为对象,分析其叶片鲜干比、叶面积、叶绿素和C、N、P含量等重要功能性状在不同年龄(5、15、25、35、45a)和不同海拔梯度(1760、1820、1880、1940、2000m)上的变化,以及C、N、P在各器官间分配格局随年龄和海拔的时空变化。结果表明:1)随树龄的增加,青杄叶面积、叶鲜干比呈增大趋势,叶P和根P含量呈下降趋势,叶有机碳含量下调,但根有机碳在上调。2)随海拔增加,叶绿素、叶面积显著增加,叶有机碳呈下降趋势,而根有机碳在增加。叶、枝、根中的N、P含量均呈先增加后减小趋势,相比之下,N、P随海拔的变化较有机碳更为显著。3)随树龄增加,C、N、P在各器官间分配格局表现为:P在幼年时于叶、根中分配比例相对较大,成年时主要集中在枝中。在研究的5~45a范围内,N分配呈叶>枝>根的稳定格局,未随年龄而显著变化。有机碳则在各器官呈近乎均匀分配的基础上随年龄增加根中比例略有增大,相反叶中比例略有下降。C、N、P并未随海拔增加呈现各器官间分配格局上的显著变化。青杄各功能性状随年龄和海拔变化并通过在各器官间相互关联和协调分配来增强其生态适应性。