与咬肌运动神经元直接联系的运动前神经元在脑干的分布

目的为了定位向咬肌运动神经元投射的最后一级运动前神经元在脑干内的分布。方法注射麦芽凝集素结合的辣根过氧化物酶(WGA-HRP)至咬肌神经逆行跨突触追踪,然后通过免疫组织化学方法显示了该类神经元。结果这类神经元分布在双侧三叉上核(Vsup)、三叉神经感觉主核背侧部(Vpdm)、小细胞网状结构(PCR)和三叉神经脊束核吻侧亚核背侧部(Vodm),以及对侧三叉神经运动核(Vmo)。数量上,Vsup,特别是注射侧Vsup中,标记的神经元数量最多;其他核团内,双侧标记的神经元的数量无明显差别。结论一侧咬肌运动神经元直接接受脑干双侧多个区域调控。     

Secretion expression of recombinant glucagon inEscherichia coli

A novel approach for the preparation of recombinant human glucagon was described. An expression vector pAGluT, containing phoA promoter, phoA signal peptide and glucagon gene, was constructed by means of genetic engineering.Escherichia coli strain YK537 was transformed with pAGluT. High-level secretory expression of recombinant human glucagon was achieved. The expression yield of recombinant human glucagon was found to be 80 mg/L, approximately 30% of the total proteins in supernatant. The biological activities and the physicochemical properties of the purified recombinant human glucagon were found to be the same as that of native glucagon. In addition, our results suggested that phoA expression system may be suitable for the expression of other small peptides.     

基于地形和主风向效应模拟山区降水空间分布

在 ANUSPL IN和 GIS空间分析技术的支持下 ,采用岷江流域内及周边地区共计 5 1个雨量站的 1988～ 2 0 0 2年各月连续观测数据 ,模拟产生岷江上游面积达 2 2 919km2的流域范围内月平均降水量的空间分布栅格。为了体现当地季风方向和坡向之间的耦合效应 ,建立主风向效应指数 (PWEI) ,并从 DEM中提取海拔高度形成两个协变量 ,以雨量站的大地坐标位置作为独立变量。降水的模拟采用样条平滑技术 ,利用降水量值和 4个变量的统计关系拟合产生样条表面 ,并进而结合 DEM和 PWEI栅格产生空间分辨率达 5 0 0 m的降水量栅格。依据归一化交叉检验值 (GCV)确定平滑参数 ,并通过多次诊断运行实现平滑降噪 ,提高预测精度。统计结果表明 ,月平均降水量的预测误差变动在 15 %～ 4 2 %之间 ,是现有雨量站分布条件所能实现的较好的结果。雨季 (5～ 9月份 )的预测误差远小于旱季 ,表明东南季风对迎风坡面有明显的致雨效应 ,并因 PWEI的运用提高了模拟精度 ;旱季 PWEI效果不明显 ,降水分配主要依赖地形。和单纯利用海拔高度一个变量相比 ,增加 PWEI可使全年平均预测误差降低 3.0 %左右。     

Effects of Aluminum Exposure on Serum Sex Hormones and Androgen Receptor Expression in Male Rats

The effects of aluminum (Al) exposure on reproductive functions of male rats were investigated. Forty male Wistar rats (4?weeks old) weighing 75-95?g were randomly divided into four groups and orally exposed to 0 (control group GC), 64.18 (low-dose group GL), 128.36 (middle-dose group GM), and 256.72 (high-dose group GH) mg/kg aluminum trichloride in drinking water for 120?days. The levels of testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were determined by radioimmunoassay. The androgen receptor (AR) expressions in testes were detected respectively by immunohistochemistry and time quantitative PCR. Results showed that the levels of T and LH in GM and GH were lower than those in GC (P??0.05). AR protein expressions in GM and GH were lower than those in GC (P?相似文献   

Effects of Aluminum Exposure on Bone Mineral Density,Mineral, and Trace Elements in Rats

The purpose of the study was to investigate the effects of aluminum (Al) exposure on bone mineral elements, trace elements, and bone mineral density (BMD) in rats. One hundred Wistar rats were divided randomly into two groups. Experimental rats were given drinking water containing aluminum chloride (AlCl₃, 430 mg Al³⁺/L), whereas control rats were given distilled water for up to 150 days. Ten rats were sacrificed in each group every 30 days. The levels of Al, calcium (Ca), phosphorus (P), magnesium (Mg), zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), selenium (Se), boron (B), and strontium (Sr) in bone and the BMD of femur were measured. Al-treated rats showed lower deposition of Ca, P, and Mg compared with control rats. Levels of trace elements (Zn, Fe, Cu, Mn, Se, B, and Sr) were significantly lower in the Al-treated group than in the control group from day 60, and the BMD of the femur metaphysis in the Al-treated group was significantly lower than in the control group on days 120 and 150. These findings indicate that long-term Al exposure reduces the levels of mineral and trace elements in bone. As a result, bone loss was induced (particularly in cancellous bone).     

Auxin modulates the enhanced development of root hairs in Arabidopsis thaliana (L.) Heynh. under elevated CO(2)

Root hairs may play a critical role in nutrient acquisition of plants grown under elevated CO(2) . This study investigated how elevated CO(2) enhanced the development of root hairs in Arabidopsis thaliana (L.) Heynh. The plants under elevated CO(2) (800 μL L(-1)) had denser and longer root hairs, and more H-positioned cells in root epidermis than those under ambient CO(2) (350 μL L(-1)). The elevated CO(2) increased auxin production in roots. Under elevated CO(2) , application of either 1-naphthoxyacetic acid (1-NOA) or N-1-naphthylphthalamic acid (NPA) blocked the enhanced development of root hairs. The opposite was true when the plants under ambient CO(2) were treated with 1-naphthylacetic acid (NAA), an auxin analogue. Furthermore, the elevated CO(2) did not enhance the development of root hairs in auxin-response mutants, axr1-3, and auxin-transporter mutants, axr4-1, aux1-7 and pin1-1. Both elevated CO(2) and NAA application increased expressions of caprice, triptychon and rho-related protein from plants 2, and decreased expressions of werewolf, GLABRA2, GLABRA3 and the transparent testa glabra 1, genes related to root-hair development, while 1-NOA and NPA application had an opposite effect. Our study suggests that elevated CO(2) enhanced the development of root hairs in Arabidopsis via the well-characterized auxin signalling and transport that modulate the initiation of root hairs and the expression of its specific genes.     

Abundance and residency dynamics of the Indo-Pacific humpback dolphin,Sousa chinensis,in the Dafengjiang River Estuary,China

Robust population size estimates are essential for informing population conservation status. Residency dynamics show population habitat use through time. Population size of Indo-Pacific humpback dolphins (Sousa chinensis) has been extensively investigated in Chinese waters, but their residency dynamics are rarely known. Mark-recapture analysis based on photo-identification records was applied to humpback dolphins in the Dafengjiang River Estuary habitat, one of the key habitats in the northern Beibu Gulf, China. Movement analyses based on lagged identification rate indicated the humpback dolphins spent, on average, 78.5 days inside and 46.9 days outside the survey area. Within the study area, the humpback dolphin abundance was 83 identifiable dolphins. A total of 353–430 humpback dolphins, estimated by POPAN modeling, were involved in this fluid habitat-use dynamic. Robust Design analysis showed strong seasonality in humpback dolphin abundance and emigration probability, implying a movement- and habitat-use pattern likely associated with spatiotemporal distribution of oceanographic characteristics and prey occurrences. Population surveys and conservation measures currently conducted in Chinese waters seldom consider seasonality in movements between habitat patches, which can be addressed by genetic analyses across habitats and cross-matching photo-identification records among neighboring habitats.     

Effects of aluminum exposure on the allergic responses and humoral immune function in rats

This study was conducted to assess effects of aluminum (Al) exposure on allergic responsive reactions and humoral immune function in rats. Forty male Wistar rats (5 weeks old) weighed 110?C120 g were randomly allocated into four groups and were orally exposed to 0, 64.18, 128.36, and 256.72 mg/kg body weight aluminum trichloride in drinking water for 120 days. The levels of immunoglobulin (Ig) G, IgA, IgM, IgE, Complement factor (C)3, and C4 in serum were determined by ELISA and nephelometric assays at the end of experiment. The results showed that the levels of IgM, C3, and C4 were lowered, and the levels of IgG, IgA, and IgE were increased in an Al-dose dependent manner. The increased in IgE level and the decreased in C3 and C4 levels indicate that Al induces allergic responses in rats; while the increased levels in IgG and IgA and the decreased level in IgM suggest that Al disorders the humoral immune function in rats.     

Secretion expression of recombinant glucagon in Escherichia coli

A novel approach for the preparation of recombinant human glucagon was described. An expression vector pAGluT, containing phoA promoter, phoA signal peptide and glucagon gene, was constructed by means of genetic engineering. Escherichia coli strain YK537 was transformed with pAGluT. High-level secretory expression of recombinant human glucagon was achieved. The expression yield of recombinant human glucagon was found to be 80 mg/L, approximately 30% of the total proteins in supernatant. The biological activities and the physicochemical properties of the purified recombinant human glucagon were found to be the same as that of native glucagon. In addition, our results suggested that phoA expression system may be suitable for the expression of other small peptides.