转鲑鱼降钙素基因酵母对体外培养破骨细胞的影响

用机械分离的方法获得新生Wistar大鼠的破骨细胞,在培养液中分别加入经肠激酶酶切的转鲑鱼降钙素基因酵母的上清液和密钙息（Miacalcic,鲑鱼降钙素注射液）,以HE染色观察破骨细胞形态,Image-Pro Plus图像软件分析骨片上骨吸收陷窝的面积,骨片培养7天,吸收陷窝结果显示,转鲑鱼降钙素对破骨细胞吸收功能具有明显的抑制作用。     

Cell cycle-dependent coupling of the calcitonin receptor to different G proteins.

Calcitonin is a calcium regulating peptide hormone with binding sites in kidney and bone as well as in the central nervous system. The mechanisms of signal transduction by calcitonin receptors were studied in a pig kidney cell line where the hormone was found to regulate sodium pumps. Calcitonin receptors activated the cyclic adenosine monophosphate (cAMP) or the protein kinase C (PKC) pathways. The two transduction pathways required guanosine triphosphate (GTP)-binding proteins (G proteins) (the choleratoxin sensitive Gs and the pertussis toxin sensitive Gi, respectively) and led to opposite biological responses. Moreover, selective activation of one or the other pathway was cell cycle-dependent. Therefore, calcitonin may induce different biological responses in target cells depending on their positions in the cell cycle. Such a modulation of ligand-induced responses could be of importance in rapidly growing cell populations such as during embryogenesis, growth, and tumor formation.     

Interaction of calcitonin and calcitonin gene-related peptide at receptor sites in target tissues

Discrete receptor sites for calcitonin (CT) and calcitonin gene-related peptide (CGRP) were found in the nervous system and in peripheral tissues. Each peptide was capable of cross-reacting with the specific receptor of the other. In contrast to CT receptors, CGRP receptors were not linked to adenylate cyclase. However, CGRP could stimulate adenylate cyclase in CT target tissues apparently by interacting with CT receptors. The relative abilities of CGRP and mammalian CT to inhibit CT binding suggest that CGRP could serve as an endogenous ligand for CT receptors in the central nervous system.     

开发一种预防和治疗骨质疏松症的功能性生菜

骨质疏松症严重威胁着人类的健康,鲑鱼降钙素是一种治疗骨质疏松的有效药,但是昂贵的价格限制了它的使用。本研究以生菜作为生物反应器来表达降钙素中生物活性较高的鲑鱼降钙素,以期通过鲜食表达降钙素的生菜达到防止或治疗骨质疏松目的,同时可大大降低生产成本。首先按植物偏爱密码子设计合成了编码鲑鱼降钙素的msCT基因,其次考虑到转基因产品安全性问题,构建植物双元表达载体p35S-2300-twinT—DNA：：pil—msCT：：noster,利用农杆菌介导进行生菜转化。经PCR和Southem blot确认得到了12株独立的转基因植株。同时RT-PCR分析表明鲑鱼降钙素在To代转基因植株中成功表达,而且表达量存在显著差异,为利用植物生物反应器生产治疗用降钙素奠定了基础。     

Autoradiographic evidence for a calcitonin receptor on testicular Leydig cells

Previous studies have indicated that there is a relation between testicular function and adequate concentrations of zinc in testicular cells, and that calcitonin alters cellular zinc transfer in the testis. The present studies provide autoradiographic evidence that calcitonin binds in vivo to the cell membrane of testicular Leydig cells. The data thus confirm the presence of the testicular cell membrane calcitonin receptors that were previously demonstrated indirectly by Scatchard analysis of data collected from binding studies.     

Global assessment of organic contaminants in farmed salmon

The annual global production of farmed salmon has increased by a factor of 40 during the past two decades. Salmon from farms in northern Europe, North America, and Chile are now available widely year-round at relatively low prices. Salmon farms have been criticized for their ecological effects, but the potential human health risks of farmed salmon consumption have not been examined rigorously. Having analyzed over 2 metric tons of farmed and wild salmon from around the world for organochlorine contaminants, we show that concentrations of these contaminants are significantly higher in farmed salmon than in wild. European-raised salmon have significantly greater contaminant loads than those raised in North and South America, indicating the need for further investigation into the sources of contamination. Risk analysis indicates that consumption of farmed Atlantic salmon may pose health risks that detract from the beneficial effects of fish consumption.     

Declining wild salmon populations in relation to parasites from farm salmon

Rather than benefiting wild fish, industrial aquaculture may contribute to declines in ocean fisheries and ecosystems. Farm salmon are commonly infected with salmon lice (Lepeophtheirus salmonis), which are native ectoparasitic copepods. We show that recurrent louse infestations of wild juvenile pink salmon (Oncorhynchus gorbuscha), all associated with salmon farms, have depressed wild pink salmon populations and placed them on a trajectory toward rapid local extinction. The louse-induced mortality of pink salmon is commonly over 80% and exceeds previous fishing mortality. If outbreaks continue, then local extinction is certain, and a 99% collapse in pink salmon population abundance is expected in four salmon generations. These results suggest that salmon farms can cause parasite outbreaks that erode the capacity of a coastal ecosystem to support wild salmon populations.     

Apolipoprotein E: cholesterol transport protein with expanding role in cell biology

Apolipoprotein E is a plasma protein that serves as a ligand for low density lipoprotein receptors and, through its interaction with these receptors, participates in the transport of cholesterol and other lipids among various cells of the body. A mutant form of apolipoprotein E that is defective in binding to low density lipoprotein receptors is associated with familial type III hyperlipoproteinemia, a genetic disorder characterized by elevated plasma cholesterol levels and accelerated coronary artery disease. Apolipoprotein E is synthesized in various organs, including liver, brain, spleen, and kidney, and is present in high concentrations in interstitial fluid, where it appears to participate in cholesterol redistribution from cells with excess cholesterol to those requiring cholesterol. Apolipo-protein E also appears to be involved in the repair response to tissue injury; for example, markedly increased amounts of apolipoprotein E are found at sites of peripheral nerve injury and regeneration. Other functions of apolipoprotein E, unrelated to lipid transport, are becoming known, including immunoregulation and modulation of cell growth and differentiation.     

Differences in thermal tolerance among sockeye salmon populations

Climate change-induced increases in summer water temperature have been associated with elevated mortality of adult sockeye salmon (Oncorhynchus nerka) during river migration. We show that cardiorespiratory physiology varies at the population level among Fraser River sockeye salmon and relates to historical environmental conditions encountered while migrating. Fish from populations with more challenging migratory environments have greater aerobic scope, larger hearts, and better coronary supply. Furthermore, thermal optima for aerobic, cardiac, and heart rate scopes are consistent with the historic river temperature ranges for each population. This study suggests that physiological adaptation occurs at a very local scale, with population-specific thermal limits being set by physiological limitations in aerobic performance, possibly due to cardiac collapse at high temperatures.     

Physiological role of silent receptors of atrial natriuretic factor

A ring-deleted analog of atrial natriuretic factor--des[Gln18, Ser19, Gly20, Leu21, Gly22] ANF4-23-NH2 (C-ANF4-23)--binds with high affinity to approximately 99% of ANF receptors in the isolated perfused rat kidney. In this preparation, C-ANF4-23 is devoid of detectable renal effects and does not antagonize any of the known renal hemodynamic and natriuretic actions of biologically active ANF1-28. In contrast, both C-ANF4-23 and ANF1-28 increase sodium excretion and decrease blood pressure in intact anesthetized rats. This apparent contradiction is resolved by the finding that the ring-deleted analog markedly increases plasma levels of endogenous immunoreactive ANF in the rat. The results show that the majority of the renal receptors of ANF are biologically silent. This new class of receptors may serve as specific peripheral storage-clearance binding sites, acting as a hormonal buffer system to modulate plasma levels of ANF.     

Impacts of salmon on riparian plant diversity

The study of natural gradients in nutrient subsidies between ecosystems allows for predictions of how changes in one system can affect biodiversity in another. We performed a large-scale empirical test of the role of Pacific salmon (Oncorhynchus spp.) in structuring riparian plant communities. A comparison of 50 watersheds in the remote Great Bear Rainforest of British Columbia's central coast in Canada shows that salmon influence nutrient loading to plants,shifting plant communities toward nutrient-rich species, which in turn decreases plant diversity.These effects are mediated by interactions between salmon density and the physical characteristics of watersheds. Predicting how salmon affect terrestrial ecosystems is central to conservation plans that aim to better integrate ecosystem values into resource management.     

A continuous cell-free translation system capable of producing polypeptides in high yield

A cell-free translation system has been constructed that uses a continuous flow of the feeding buffer [including amino acids, adenosine triphosphate (ATP), and guanosine triphosphate (GTP)] through the reaction mixture and a continuous removal of a polypeptide product. Both prokaryotic (Escherichia coli) and eukaryotic (wheat embryos, Triticum sp.) versions of the system have been tested. In both cases the system has proven active for long times, synthesizing polypeptides at a high constant rate for tens of hours. With the use of MS2 phage RNA or brome mosaic virus RNA 4 as templates, 100 copies of viral coat proteins per RNA were synthesized for 20 hours in the prokaryotic or eukaryotic system, respectively. With synthetic calcitonin messenger RNA, 150 to 300 copies of calcitonin polypeptide were produced per messenger RNA in both types of continuous translation systems for 40 hours.     

Mineralocorticoid action: target tissue specificity is enzyme, not receptor, mediated

Mineralocorticoid receptors, both when in tissue extracts and when recombinant-derived, have equal affinity for the physiological mineralocorticoid aldosterone and for the glucocorticoids cortisol and corticosterone, which circulate at much higher concentrations than aldosterone. Such receptors are found in physiological mineralocorticoid target tissues (kidney, parotid, and colon) and in nontarget tissues such as hippocampus and heart. In mineralocorticoid target tissues the receptors are selective for aldosterone in vivo because of the presence of the enzyme 11 beta-hydroxy-steroid dehydrogenase, which converts cortisol and corticosterone, but not aldosterone, to their 11-keto analogs. These analogs cannot bind to mineralocorticoid receptors.     

曙红与鲑鱼精蛋白显色反应的研究

[目的]对曙红与鲑鱼精蛋白显色的反应进行研究。[方法]采用分光光度法,研究曙红(醇溶)与鲑鱼精蛋白在聚乙烯醇(PVA)存在时的结合反应,并且研究了显色反应的条件和影响灵敏度的因素,确定了最佳反应条件。[结果]以试剂空白为参比,曙红-硫酸鱼精蛋白复合物的最大吸收波长为542 nm,最大吸收波长处的吸光度与蛋白质的浓度呈良好的线性关系,可用于蛋白质的定量测定。[结论]该方法灵敏度高、线性关系好、试剂稳定、毒性小,且曙红、硫酸鱼精蛋白复合物不易黏附在容器壁上,操作简便、快速、结果准确。     

Autocrine stimulation of intracellular PDGF receptors in v-sis-transformed cells

Autocrine activation of platelet-derived growth factor (PDGF) receptors is the mechanism of transformation by the v-sis oncogene. Since the addition of PDGF does not transform normal cells, autocrine mechanisms may involve unique pathways of receptor activation. In this study autocrine stimulation of the PDGF receptor was observed in v-sis-transformed normal rat kidney (NRK) cells. In contrast to receptor activation in normal cells, autocrine activation of PDGF receptors in v-sis-transformed cells occurred in intracellular compartments, disrupting receptor processing and diverting receptors and their precursors to a chloroquine-sensitive degradation pathway. These findings show that intracellular activation of receptors by autocrine mechanisms may play a role in cell transformation.     

日本知床半岛海域细鳞大马哈鱼和大马哈鱼的移动生态调查

在北海道知床半岛周边海域,用小型数据记录器监测细鳞大马哈鱼Oncorhyncus gorbuscha和大马哈鱼O.keta的回归游泳行为,探讨其与环境水温的关系。数据记录间隔时间为1 s,连续记录时间为226 h。于2008年8月至10月期间,在知床沿岸放流了带有数据记录器的洄游途中的大马哈鱼和细鳞大马哈鱼个体(分别为30尾和5尾),分别有13尾、3尾个体被捕获。研究表明:试验个体有一系列的上浮和下沉行为,并且频繁地回到表层水面,垂直移动中的深潜水是对表层高水温和暖流分层水中的一种适温调节行为。因此,尽管表层水温较高,性成熟后的大马哈鱼仍会回到表层水面寻找其产卵场所。     

Memory-blocking agents: effects on olfactory discrimination in homing salmon

Homing salmon were injected intracranially with puromycin, actinomycin D, or cycloheximide. From 4 to 7 hours after such treatment these agents markedly inhibited olfactory bulbar discrimination between home water and other natural waters, including spawning sites for other groups of salmon. At longer intervals after treatment there was a partial restoration of olfactory memory-based discrimination. The dosages of the inhibitors used could be shown to have depressed incorporation of H(3)-leucine into protein by 78 percent or of H(3)-uridine into RNA by 41 percent in the salmon brains 4 hours after intracranial injection. These findings suggest that acute blockage of RNA synthesis or protein synthesis can interfere with long-term olfactory memory in anadromous salmon, at least as this function can be analyzed by electrophysiological methods. This implies that long-term olfactory memory depends upon continued metabolism of RNA and continued protein synthesis.     

Electroencephalographic evidence for retention of olfactory cues in homing coho salmon

Differences were observed in the magnitude of the evoked electroencephalographic response to 1 percent morpholine for homing coho salmon (Oncorhynchus kisutch) exposed to morpholine as fingerlings 1 month before smolting as compared to salmon not exposed to morpholine as fingerlings. These results indicate that olfactory information has been retained for 18 months, the period between smolting and the homeward migration.     

Satellite tagging and cardiac physiology reveal niche expansion in salmon sharks

Shark populations are declining globally, yet the movements and habitats of most species are unknown. We used a satellite tag attached to the dorsal fin to track salmon sharks (Lamna ditropis) for up to 3.2 years. Here we show that salmon sharks have a subarctic-to-subtropical niche, ranging from 2 degrees to 24 degrees C, and they spend winter periods in waters as cold as 2 degrees to 8 degrees C. Functional assays and protein gels reveal that the expression of excitation-contraction coupling proteins is enhanced in salmon shark hearts, which may underlie the shark's ability to maintain heart function at cold temperatures and their niche expansion into subarctic seas.     

褪黑素受体Mel 1b基因mRNA和蛋白在鸭不同组织中的表达与分布

褪黑素广泛的生理作用是通过与其膜受体(Mel 1a、Mel 1b、Mel 1c)结合介导的。褪黑素受体在机体内广泛分布,但因受体亚型、物种、组织不同而异。采用RT-PCR、real-time PCR和免疫组化技术探究了Mel 1b在鸭不同组织(包括鸭脾脏、心脏、肾脏、大脑、胸肌、卵巢、肺脏、肝脏、胰脏组织)中的表达分布及相对表达量。结果表明,鸭Mel 1b mRNA在脾脏、心脏、肾脏、大脑、胸肌、卵巢、肺脏、肝脏、胰脏中均有表达,且Mel 1b受体蛋白均存在于大脑、肺脏、肝脏、胸肌、肾脏、心脏、胰脏中(脾脏、卵巢未成功测试)。Real-time PCR结果表明,各组织中Mel 1b mRNA表达量存在差异,在卵巢中的表达量最高,其次为肺脏,在脾脏、心脏、肾脏和肝脏中的表达量也明显高于大脑中的表达,但在胸肌和胰脏中的表达量要稍低于大脑中的表达量。Mel 1b在鸭各组织中普遍表达分布,进一步说明了其介导褪黑素广泛的生理功能,特别是对生殖功能的调节。