氨肽酶N的表达及其与结石形成的关系(英文)

 为研究大鼠高胆固醇饮食时 ,肝脏氨肽酶N(APN)在实验结石形成中可能的结石发生作用 ,采用 1.2 %胆固醇饮食 4周 ,诱发新西兰兔胆囊结石形成 .根据兔APN基因cDNA序列设计引物 ,提取肝脏总RNA .利用RT PCR检测肝脏APNmRNA水平的变化 ,用组织化学方法观察肝脏毛细胆管膜上APN的表达 .观察新西兰兔胆囊结石形成过程中肝脏APN的mRNA水平的变化、APN表达及胆汁中APN活性、胆脂、总蛋白含量的变化 ,探讨APN在胆石形成中可能的作用 .经成石饲料饲养后 ,随着胆汁饱和度增加和APN活性加强 ,胆囊结石组肝脏APNmRNA水平较对照组明显增高 ,胆囊结石组胆汁中总胆固醇、CSI、总蛋白浓度及APN活性均明显高于对照组 ,且胆汁中APN活性与肝脏APN的表达及胆汁CSI增高呈正相关 .结果提示 ,当存在胆汁过饱和的情况下 ,APN很可能作为促成核因子在胆结石形成早期发挥重要作用     

Visualization of cytoskeletal changes through the life cycle inAcetabularia

Summary The cytoskeleton in the siphonous, marine green algaAcetabularia is visualized by immunocytochemistry using antibodies against plant alfa tubulin and animal smooth muscle actin. In the vegetative phase of the life cycle, when the cell grows a cylindrical stalk and until the reproductive cap is completed, actin forms continuous, parallel bundles that extend through the entire length of the stalk and cap rays respectively. Microtubules (MTs) cannot be detected until the primary nucleus, located in the rhizoid of the giant cell, divides to form thousands of secondary nuclei. MTs can then be seen radiating from each secondary nucleus that is encountered in the stalk on its migration upwards into the cap rays. They are oriented mostly parallel to the long axis of the cell. At arrival in the cap rays up to the white spot stage, when nuclei assume equidistant positions in the cap ray cytoplasm, a radiating system of MTs forms around each nucleus and dramatically increases until impressive radial arrays have developed. This phase coincides with a disappearance of actin bundles in the cap rays, but they are retained in the stalk cytoplasm. Shortly after that additional MTs appear around the disk like partitions of cap ray cytoplasm. Concomitantly, bundles of actin reappear colinearly with the circumferrential MTs eventually forming complete rings around each disk of cap ray cytoplasm. During this process the compartments of the future cysts are gradually bulging outwards and simultaneously the rings of actin sink inwards until domes are formed with the nuclei fixed in the top centers of the domes. At this stage the peripheral areas of the radiating MT systems around the nuclei start to break down, whereas the circumferrential MT systems remain intact. Subsequently, the rings of both actin and MTs decrease in diameter, and finally contract to a spot opposite the nucleus, while the cysts continue to develop their oval shape. After the cysts have become separated, they round up and enter several rounds of nuclear divisions. MTs form short radial arrays around each nucleus with minor changes due to a reduction of MTs during division followed by a reappearance after completion of each division. Actin is rearranged in the cysts to a cortical network of randomly oriented, short bundles, that is maintained until gamete formation sets in.These findings accentuate the involvement of Cytoskeletal elements in the key steps of morphogenesis inAcetabularia to an extent that is unknown in higher plants.     

Amelioration of cadmium-induced cardiac impairment by taurine

The present study has been designed to investigate the protective role of taurine (2-aminoethanesulfonic acid), a sulfur containing conditionally essential amino acid, against cadmium-induced cardiac dysfunction in mice. Cadmium chloride (CdCl(2)) was used as the source of cadmium and it was administered orally at a dose of 4mg/kg body weight for 6 days. Cadmium exposure caused significant accumulation of the cadmium and iron in mice hearts tissue. Levels of serum specific markers related to cardiac impairments, e.g. total cholesterol, HDL cholesterol and triglyceride were altered due to cadmium toxicity. Reduction in the activities of antioxidant enzymes, namely, superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx) and glucose-6-phosphate dehydrogenase (G6PD) have been observed in cadmium exposed mice. Cadmium intoxication also decreased the cardiac glutathione (GSH) and total thiols contents and increased the levels of oxidized glutathione (GSSG), lipid peroxidation end products, protein carbonyl content and the extent of DNA fragmentation. Oral administration of taurine at a dose of 100mg/kg body weight for 5 days, however, prevented all the toxin-induced oxidative impairments mentioned above. "Ferric Reducing/Antioxidant Power (FRAP) assay" showed that taurine could protect the cardiac tissue by preventing cadmium-induced reduction of the intracellular antioxidant power. Histological examination of cardiac segments also supported the beneficial role of taurine against cadmium-induced damages in the murine hearts. Effect of a well established antioxidant, vitamin C has been included in the study as a positive control. Combining all, results suggest that taurine attenuates cadmium-induced impairment in mice hearts.     

Hemolysis of rabbit erythrocytes in the presence of copper ions

The hemolysis of red blood cells (RBC) induced by Cu(II) is modified by ceruloplasmin (Cp) and albumin. The time course of hemolysis for rabbit RBC by Cu(II) consisted of two parts, an induction period followed by a catastrophic lysis period. The induction period decreased and the lysis rate increased with increasing Cu(II) concentration. Cp or albumin, modified Cu(II) induced hemolysis, by increasing the duration of the induction period and decreasing the overall rate of hemolysis of RBC. The catastrophic lysis period coincided with a sharp increase in the formation of metHb within the cell and in a rapid uptake of Cu(II). The presence of Cp led to an increase in the induction period prior to the rapid increase in metHb formation and in Cu(II) uptake. Porcine Cp was prepared with either two or three nonprosthetic copper binding sites (sites where Cu(II) is easily removed by passing over Chelex-100). Cp with three nonprosthetic binding sites gave more protection than Cp with two. Likewise, albumin can be prepared with three and five nonprosthetic copper binding sites. The albumin with five sites gave more protection than the albumin with three sites.     

光照、湿度和培养基对苎麻疫霉卵孢子产生量的影响

采用3因素随机区组设计研究了光照、湿度和培养基对苎麻疫霉(hytophthoraboehmeriae)卵孢子产生量的影响。结果表明,各因子对卵孢子产生量的影响效应大小次序为培养基>光照>湿度,其中培养基和光照两因子影响均在0.01水平上显着。在供试的4种常用培养基上,卵孢子产生量的大小次序为：SLA培养基(SLA)>利马豆培养基(LBA)>V₆汁培养基(V₆A)>澄清的V₆汁培养基(V₆B).在设置的3种光照条件中,卵孢子产生量以连续黑暗处理最高,连续光照最低,光照与黑暗交替处理居中。3个试验因子间的所有互作对卵孢子产生量均有极显着的影响。在不同光照、湿度、培养基组合中,卵孢子产生量以低湿+连续黑暗+SLA组合最高,低湿+连续光照+V₆B组合最低。     

Fibromodulin is expressed by both chondrocytes and osteoblasts during fetal bone development

Fibromodulin, a keratan-sulfate proteoglycan, was first isolated in articular cartilage and tendons. We have identified fibromodulin as a gene regulated during BMP-2-induced differentiation of a mouse prechondroblastic cell line. Because expression of fibromodulin during endochondral bone formation has not been studied, we examined whether selected cells of the chondrocytic and osteoblastic lineage expressed fibromodulin. Fibromodulin mRNA was detected in conditionally immortalized murine bone marrow stromal cells, osteoblasts, and growth plate chondrocytes, as well as in primary murine calvarial osteoblasts. We, therefore, investigated the temporo-spatial expression of fibromodulin in vivo during endochondral bone formation by in situ hybridization. Fibromodulin was first detected at 15.5 days post coitus (dpc) in the perichondrium and proliferating chondrocytes. Fibromodulin mRNA was also detected at 15.5 dpc in the bone collar and periosteum. At later time points fibromodulin was expressed in the primary spongiosa and the endosteum. To determine whether fibromodulin was expressed during intramembranous bone formation as well, in situ hybridization was performed on calvariae. Fibromodulin mRNA was present in calvarial osteoblasts from 15.5 dpc. These results demonstrate that fibromodulin is developmentally expressed in cartilage and bone cells during endochondral and intramembranous ossification. These findings suggest that this extracellular matrix protein plays a role in both endochondral and intramembranous bone formation.     

The use of quantitative imaging to investigate regulators of membrane trafficking in Arabidopsis stomatal closure

Expansion of gene families facilitates robustness and evolvability of biological processes but impedes functional genetic dissection of signalling pathways. To address this, quantitative analysis of single cell responses can help characterize the redundancy within gene families. We developed high‐throughput quantitative imaging of stomatal closure, a response of plant guard cells, and performed a reverse genetic screen in a group of Arabidopsis mutants to five stimuli. Focussing on the intersection between guard cell signalling and the endomembrane system, we identified eight clusters based on the mutant stomatal responses. Mutants generally affected in stomatal closure were mostly in genes encoding SNARE and SCAMP membrane regulators. By contrast, mutants in RAB5 GTPase genes played specific roles in stomatal closure to microbial but not drought stress. Together with timed quantitative imaging of endosomes revealing sequential patterns in FLS2 trafficking, our imaging pipeline can resolve non‐redundant functions of the RAB5 GTPase gene family. Finally, we provide a valuable image‐based tool to dissect guard cell responses and outline a genetic framework of stomatal closure.      

Immunoneutralization of insulin partially modifies dorsoventral patterning in developing frog embryos

Determination of anteroposterior and dorsoventral axes is an important early event in the development of vertebrates involving extensive cellular interactions including inductive events. Recently we showed that insulin plays an essential role in prepancreatic development of the frogMicrohyla ornata. In the present study we have investigated the effects of immunoneutralization of endogenous insulin on the process of pattern formation. Treatment of neurulating embryos with antiserum to insulin caused abnormal pattern formation. The defects included loss of normal architecture of the neural tube, reduction in the size of the neural tube and, most conspicuously, rotation of the dorsoventral axis of the neural tube, notochord and adjoining mesodermal elements. The effects could be alleviated partially by pretreatment of embryos with exogenous insulin. This supports our belief that insulin plays an important role in induction and pattern formation of the amphibian nervous system. In addition, using 2-deoxy-α-D-glucose, an inhibitor of glucose metabolism, it is shown that the stimulatory effects of exogenous insulin on developing frog embryos are, at least partially, through the glucose metabolism pathway. Preliminary results of this study were presented at the National Symposium on Genes and Human Environment, held at Hyderabad, February 1994 and DAE Symposium on Stress and Adaptive Responses in Biological Systems, held at Vadodara, March 1994.     

Pigmentation pattern formation in butterflies: experiments and models

Butterfly pigmentation patterns are one of the most spectacular and vivid examples of pattern formation in biology. They have attracted much attention from experimentalists and theoreticians, who have tried to understand the underlying genetic, chemical and physical processes that lead to patterning. In this paper, we present a brief review of this field by first considering the generation of the localised, eyespot, patterns and then the formation of more globally controlled patterns. We present some new results applied to pattern formation on the wing of the mimetic butterfly Papilio dardanus.     

Smad3基因剔除小鼠特异性免疫功能的研究

目的　研究Smad3基因剔除小鼠的体液免疫和细胞免疫。方法　采用流式细胞仪对其细胞免疫和体液免疫进行检测 ;并且应用ELISA方法对IgG抗体的吸光度进行测定。结果　纯合型 (- - )小鼠CD8 、CD4 CD8 、IgG雌雄之间差异有显著性 ;CD4 、CD8 、CD3 、CD19 、IgG的值低于野生型 ;结论　CD4 CD8 的比值同野生型比较属于异常 (与人的范围比较 )。因此 ,为在人类免疫疾病研究方面选用该动物提供一定的参考价值