半胱胺盐酸盐和LHRH-A对黄鳍鲷IGF-Ⅰ基因表达和生长的影响

本文以黄鳍鲷 (Sparuslatus)为研究对象 ,利用GeneRaceTM 技术 ,从其肝组织中克隆出类胰岛素生长因子 (IGF Ⅰ )cDNA ,并应用半定量RT PCR方法研究了半胱胺盐酸盐 (Cysteaminehydrochloride)和LHRH A对其肝组织IGF Ⅰ基因表达的影响。黄鳍鲷IGF ⅠcDNA全长为 84 0bp ,编码 185aa多肽 ;序列分析表明 ,黄鳍鲷IGF Ⅰ基因编码的氨基酸序列与金鱼的同源性为 75 8% ,与牙鲆的同源性为 86 5 % ,与同属鲷科的黑鲷同源性高达 10 0 % ,证明鱼类类胰岛素生长因子是非常保守的 ,E区域分析结果表明黄鳍鲷IGF Ⅰ属Ea 4型。在饲料中投喂CSH、LHRH A等添加剂 ,实验组黄鳍鲷鱼种的相对生长率、垂体GH含量、肝脏IGF ⅠmRNA水平均显著高于对照组。以上结果提示 :CSH、LHRH A能促进黄鳍鲷生长激素的合成和IGF Ⅰ基因的表达 ,从而促进鱼种的生长     

Cytokine secretion requires phosphatidylcholine synthesis

Choline cytidylyltransferase (CCT) is the rate-limiting enzyme in the phosphatidylcholine biosynthetic pathway. Here, we demonstrate that CCT alpha-mediated phosphatidylcholine synthesis is required to maintain normal Golgi structure and function as well as cytokine secretion from the Golgi complex. CCT alpha is localized to the trans-Golgi region and its expression is increased in lipopolysaccharide (LPS)-stimulated wild-type macrophages. Although LPS triggers transient reorganization of Golgi morphology in wild-type macrophages, similar structural alterations persist in CCT alpha-deficient cells. Pro-tumor necrosis factor alpha and interleukin-6 remain lodged in the secretory compartment of CCT alpha-deficient macrophages after LPS stimulation. However, the lysosomal-mediated secretion pathways for interleukin-1 beta secretion and constitutive apolipoprotein E secretion are unaltered. Exogenous lysophosphatidylcholine restores LPS-stimulated secretion from CCT alpha-deficient cells, and elevated diacylglycerol levels alone do not impede secretion of pro-tumor necrosis factor alpha or interleukin-6. These results identify CCT alpha as a key component in membrane biogenesis during LPS-stimulated cytokine secretion from the Golgi complex.     

AutoDecon, a deconvolution algorithm for identification and characterization of luteinizing hormone secretory bursts: description and validation using synthetic data

Hormone signaling is often pulsatile, and multiparameter deconvolution procedures have long been used to identify and characterize secretory events. However, the existing programs have serious limitations, including the subjective nature of initial peak selection, lack of statistical verification of presumed bursts, and user-unfriendliness of the application. Here we describe a novel deconvolution program, AutoDecon, which addresses these concerns. We validate AutoDecon for application to serum luteinizing hormone (LH) concentration time series using synthetic data mimicking real data from normal women and then comparing the performance of AutoDecon with the performance of the widely employed hormone pulsatility analysis program Cluster. The sensitivity of AutoDecon is higher than that of Cluster (∼ 96% vs. 80%, P = 0.001). However, Cluster had a lower false-positive detection rate than did AutoDecon (6% vs. 1%, P = 0.001). Further analysis demonstrated that the pulsatility parameters recovered by AutoDecon were indistinguishable from those characterizing the synthetic data and that sampling at 5- or 10-min intervals was optimal for maximizing the sensitivity rates for LH. Accordingly, AutoDecon presents a viable nonsubjective alternative to previous pulse detection algorithms for the analysis of LH data. It is applicable to other pulsatile hormone concentration time series and many other pulsatile phenomena. The software is free and downloadable at http://mljohnson.pharm.virginia.edu/home.html.     

Habitat selection and reproductive success of Ortolan Buntings Emberiza hortulana on farmland in central Sweden – the importance of habitat heterogeneity

Many granivorous birds have shown severe population declines in Europe during recent decades. The aim of the present study was to analyse habitat preferences and reproductive success of one such species, the Ortolan Bunting Emberiza hortulana, in different farmland habitats in south‐central Sweden. Four seemingly different land‐use types were preferred: permanent set‐asides, short rotation coppice, and grazed and unmanaged semi‐natural pastures. Territories and random sites differed considerably in the proportion of these preferred land‐use types; 39% of territories had > 70% preferred habitat (at the 100‐m scale) compared to 5% of random sites. In contrast, 22% of territories and 65% of random sites had no preferred habitats. All the preferred habitats had heterogeneous ground vegetation characterized by patches with bare ground, or at least sparse ground vegetation, intermixed with patches with taller vegetation. Ortolan Buntings also preferred a heterogeneous habitat structure with occurrence of field islets, shrubby edges, barns and electric wires, which could act as song posts or suitable nest‐sites, in 88% of territories. At a larger (1‐km square) scale, territories occupied by pairs aggregated strongly in areas with high proportions of preferred habitats. The number of territories with single males correlated positively with the number of pairs, which suggests that conspecific attraction may influence territory distribution. No measured habitat factors were related to reproductive success. However, due to habitat preferences and the higher proportion of paired males in one habitat type (set‐aside), the production of young (fledglings/ha) is expected to be higher in set‐asides, as well as in short‐rotation coppices and semi‐natural pastures. Thus, these habitats are important for the conservation of the Ortolan Bunting. Large areas with habitat structures such as field islets are especially important because the Ortolan Bunting breeds in aggregations in these areas.     

Salmonella enterica requires ApbC function for growth on tricarballylate: evidence of functional redundancy between ApbC and IscU

Mutants of Salmonella enterica lacking apbC have nutritional and biochemical properties indicative of defects in [Fe-S] cluster metabolism. Here we show that apbC is required for S. enterica to use tricarballylate as a carbon and energy source. Tricarballylate catabolism requires three gene products, TcuA, TcuB, and TcuC. Of relevance to this work is the TcuB protein, which has two [4Fe-4S] clusters required for function, making it a logical target for the apbC effect. TcuB activity was 100-fold lower in an apbC mutant than in the isogenic apbC(+) strain. Genetic data show that derepression of the iscRSUA-hscAB-fdx-orf3 operon or overexpression of iscU from a plasmid compensates for the lack of ApbC during growth on tricarballylate. The studies described herein provide evidence that the scaffold protein IscU has a functional overlap with ApbC and that ApbC function is involved in the synthesis of active TcuB.     

Insight into disulfide bond catalysis in Chlamydia from the structure and function of DsbH, a novel oxidoreductase

The Chlamydia family of human pathogens uses outer envelope proteins that are highly cross-linked by disulfide bonds but nevertheless keeps an unusually high number of unpaired cysteines in its secreted proteins. To gain insight into chlamydial disulfide bond catalysis, the structure, function, and substrate interaction of a novel periplasmic oxidoreductase, termed DsbH, were determined. The structure of DsbH, its redox potential of -269 mV, and its functional properties are similar to thioredoxin and the C-terminal domain of DsbD, i.e. characteristic of a disulfide reductase. As compared with these proteins, the two central residues of the DsbH catalytic motif (CMWC) shield the catalytic disulfide bond and are selectively perturbed by a peptide ligand. This shows that these oxidoreductase family characteristic residues are not only important in determining the redox potential of the catalytic disulfide bond but also in influencing substrate interactions. For DsbH, three functional roles are conceivable; that is, reducing intermolecular disulfides between proteins and small molecules, keeping a specific subset of exported proteins reduced, or maintaining the periplasm of Chlamydia in a generally reducing state.     

Determination of vertebral endplate deformation under load using micro-computed tomography

Endplate strength plays an important role in preventing vertebral failure of normal vertebrae and in cases where surgical intervention has replaced the disc with an implant or has altered the vertebral loading. We have developed a non-contact method based on the principles of image guided failure analysis, mechanical testing, and micro-computed tomography analysis, which allows for in vitro quantification of endplate deformation under axial load. The method allows for the implementation of a repeated measures experimental design, each specimen acting as its own control. Our methodology was validated using cadaveric functional spine units, loaded stepwise from 200 N to a maximum of 2000 N. The loading protocol was repeated over two days, allowing time for recovery of the disc mechanical properties. We found no meaningful difference in measured force, stiffness, and endplate deformation between day 1 and day 2. The mean fiducial registration error was less than 0.015 mm for all three axes. Endplate deformation could be reproducibly estimated. The root mean squared error was 0.03 mm, which is the effective precision of the method. Using this micro-CT based method, the effect of interbody implants, grafts, disc replacement strategies, and surgical procedures such as nucleotomy and vertebral cement augmentation on endplate mechanical behaviour can be ascertained.     

Mercury toxicity presenting as chronic fatigue, memory impairment and depression: diagnosis, treatment, susceptibility, and outcomes in a New Zealand general practice setting (1994-2006)

In a group of 465 patients diagnosed as having chronic mercury toxicity (CMT), 32.3% had severe fatigue, 88.8% had memory loss, and 27.5% had depression. A significant correlation was found between CMT and the Apo-lipoprotein E4 genotype (p=0.001). An investigation into an additional 864 consecutively seen general practice patients, resulted in 30.3% having evidence consistent with CMT, and once again a significant correlation was found with the APO-E4 genotype (p=0.001). Removal of amalgam mercury fillings when combined with appropriate treatment resulted in a significant symptom reduction (p<0.001) to levels reported by healthy subjects.