Global transcriptional response of pig brain and lung to natural infection by Pseudorabies virus

Background  

Pseudorabies virus (PRV) is an alphaherpesviruses whose native host is pig. PRV infection mainly causes signs of central nervous system disorder in young pigs, and respiratory system diseases in the adult.     

Variation in the ribosomal internal transcribed spacers (ITS1 and ITS2) among eight taxa of the Mimulus guttatus species complex

The internal transcribed spacer region (ITS1 and ITS2) of the 18S-25S nuclear ribosomal DNA sequence and the intervening 5.8S region were sequenced from three individuals in each of eight taxa of the Mimulus guttatus species complex. Three discrete variants, or "types," of ITS sequences were found, among which 30%-40% of sites differed, compared with 1%-2% within types. Dot plots indicate that these types were not related by conspicuous rearrangements or inversions. More than one ITS type was often found in the same taxon, and two of three ITS types span species boundaries, indicating their presence prior to speciation. These ITS sequences showed essentially no positional homology with the nearest sequenced relative, tomato. In contrast, the 5.8S region was relatively unvaried, with 8 of 162 sites varied in the sample among all eight taxa. The phylogeny inferred by the most common ITS sequence type, rooted by the two other ITS types, agreed with isozymes in showing the distinctness of M. nudatus, M. laciniatus, and M. tilingii from the other five taxa.      

Methenyltetrahydrofolate synthetase regulates folate turnover and accumulation

Cellular folate deficiency impairs one-carbon metabolism, resulting in decreased fidelity of DNA synthesis and inhibition of numerous S-adenosylmethionine-dependent methylation reactions including protein and DNA methylation. Cellular folate concentrations are influenced by folate availability, cellular folate transport efficiency, folate polyglutamylation, and folate turnover specifically through degradation. Folate cofactors are highly susceptible to oxidative degradation in vitro with the exception of 5-formyltetrahydrofolate, which may be a storage form of folate. In this study, we determined the effects of depleting cytoplasmic 5-formyltetrahydrofolate on cellular folate concentrations and folate turnover rates in cell cultures by expressing the human methenyltetrahydrofolate synthetase cDNA in human MCF-7 cells and SH-SY5Y neuroblastoma. Cells with increased methenyltetrahydrofolate synthetase activity exhibited: 1) increased rates of folate turnover, 2) elevated generation of p-aminobenzoylglutamate in culture medium, 3) depressed cellular folate concentrations independent of medium folic acid concentrations, and 4) increased average polyglutamate chain lengths of folate cofactors. These data indicate that folate catabolism and folate polyglutamylation are competitive reactions that influence cellular folate concentrations, and that increased methenyltetrahydrofolate synthetase activity accelerates folate turnover rates, depletes cellular folate concentrations, and may account in part for tissue-specific differences in folate accumulation.     

Do microcracks decrease or increase fatigue resistance in cortical bone?

Fatigue of cortical bone produces microcracks; it has been hypothesized that these cracks are analogous to those occurring in engineered composite materials and constitute a similar mechanism for fatigue resistance. However, the numbers of these linear microcracks increase substantially with age, suggesting that they contribute to increased fracture incidence among the elderly. To test these opposing hypotheses, we fatigued 20 beams of femoral cortical bone from elderly men and women in load-controlled four point bending having initial strain ranges of 3000 or 5000 microstrain. Loading was stopped at fracture or 10(6) cycles, whichever occurred first, and microcrack density and length were measured in the loaded region and in a control region that was not loaded. We studied the dependence of fatigue life and induced microdamage on initial microdamage, cortical region, subject gender and age, and several other variables. When the effect of modulus variability was controlled, longer fatigue life was associated with higher rather than lower initial crack density, particularly in the medial cortex. The increase in crack density following fatigue loading was greater in specimens from older individuals and those initially having longer microcracks. Crack density increased as much in specimens fatigued short of the failure point as in those that fractured, and microcracks were, on average, shorter in specimens with greater numbers of resorption spaces, a measure of remodeling rate.     

小黄皮叶挥发油的化学成分

利用水蒸气蒸馏法提取小黄皮叶挥发油,运用毛细管气相色谱-质谱联用法对挥发油进行了分析,分离出40个峰,鉴定了其中的37种成分,所鉴定成分占挥发油总量的99.87%,其主要化学成分为单萜及倍半萜类化合物。     

Variability of uterine cervical anatomy in the white-tailed gnu (Connochaetes gnou)

Examination of the reproductive anatomy of six female white-tailed gnu revealed duplex uterus with varying degrees of cervical division. The division ranged from 36 to 100% of the length of the cervix, with one animal exhibiting double external ossa. This variability in reproductive anatomy could be important in artificial insemination or embryo transfer procedures in this species.     

An investigation of the interactions between lower-limb bone morphology,limb inertial properties and limb dynamics

Bone mass and size clearly affect the safety and survival of wild animals as well as human beings, however, little is known about the interactions between bone size and movement dynamics. A modeling approach was used to investigate the hypothesis that increased bone cortical area causes increased limb moments of inertia, decreased lower-limb movement maximum velocities, and increased energy requirements to sustain submaximum lower-limb locomotion movements. Custom software and digital data of a human leg were used to simulate femur, tibia, and fibula cortical bone area increases of 0%, 22%, 50%, and 80%. Limb segment masses, center of mass locations, and moments of inertia in the sagittal plane were calculated for each bone condition. Movement simulations of unloaded running and cycling motions were performed. Linear regression analyses were used to determine the magnitude of the effect cortical area has on limb moment of inertia, velocity, and the internal work required to move the limbs at a given velocity. The thigh and shank moment of inertia increased linearly up to 1.5% and 6.9%, respectively for an 80% increase in cortical area resulting in 1.3% and 2.0% decreases in maximum unloaded cycling and running velocities, respectively, and in 3.0% and 2.9% increases in internal work for the cycling and running motions, respectively. These results support the hypothesis and though small changes in movement speed and energy demands were observed, such changes may have played an important role in animal survival as bones evolved and became less robust.     

益生菌对调节脑梗死后大鼠运动功能的机制研究

探讨在脑梗死后康复期使用益生菌治疗促进大鼠运动功能恢复的机制。

成年雄性SPF级7～8周龄Wistar大鼠,体重200～250 g,共35只。25只大鼠颅内注射内皮素制作脑缺血模型,模型制作后5只大鼠死亡,剩余20只大鼠按照随机数表法分为缺血组（ISC组）和缺血+益生菌组（ISC+PB组）,每组10只。另外10只大鼠作为假手术组（SHAM组）。SHAM组大鼠仅使用生理盐水按照上述造模流程进行。各组均喂食普通大鼠饲料。ISC+PB组大鼠第7天开始使用益生菌VSL#3溶液进行灌胃,0.25 mL/(只•d)。采用原位末端转移酶标记（TdT-mediated dUTP nick-end labeling,TUNEL）凋亡试剂盒检测凋亡细胞。采用蛋白质免疫印迹法检测各组大鼠海马与梗死周边皮层脑源性神经营养因子（brain derived neurotrophic factor,BDNF）的蛋白水平变化。使用梯形平衡木测试大鼠的肢体运动功能。

ISC组大鼠TUNEL阳性细胞数量较SHAM组显著增多（t=3.278,P=0.016）,ISC+PB组大鼠的TUNEL阳性细胞数量低于ISC组（t=2.721,P=0.037）。ISC组大鼠海马与梗死周边BDNF蛋白表达水平高于SHAM组（t=2.012,P=0.032）,ISC+PB组大鼠海马与梗死周边皮层BDNF水平较ISC组进一步提高（t=1.892,P=0.021）。梯形平衡木行走实验显示ISC组大鼠产生明显的运动功能损伤（t=3.425,P=0.041）,而ISC+PB组错误率低于ISC组（t=4.131,P=0.024）。

脑梗死后益生菌通过调控BDNF水平,抑制细胞凋亡,改善运动功能。

     

5-HT_(1A)受体参与学习记忆的分子机制研究进展

5-HT(五羟色胺)能神经元是起源最早的神经元之一,在传统的神经元形成前,成长中的轴突就可释放5-HT,并且通过5-HT的各种亚型受体来实现不同的功能。近年来,随着5-HT、5-HTRs(五羟色胺受体)的基因克隆及5-HT受体选择性激动剂和拮抗剂的研究发展,5-HT系统在学习记忆中的作用越发明确,许多研究结果表明:5-HT系统在记忆的巩固、短时程记忆(STM)及长时程记忆(LTM)中起重要作用,5-HT1A受体更是在非脊椎动物及哺乳动物的脑中都高度表达,并通过相似的信号转导途径参与学习与记忆的形成和巩固。本文将介绍5-HT1A受体、5-HT1A受体激动剂、5-HT1A受体拮抗剂及其与学习记忆的联系,重点综述5-HT1A受体参与学习记忆的信号转导途径研究进展,讨论5-HT1A受体参与学习记忆的可能性分子神经生物学机制。