Differential expression of the melanocortin-4 receptor in male and female C57BL/6J mice

The melanocortin 4 receptor is a member of melanocortin receptors of G-protein-coupled receptors. By binding to melanocortin receptor agonists or antagonists, MC4R participates in the regulating of food intake, weight, energy homeostasis and sexual behavior. By activating the protein kinase A and leptin-melanocortin signalling pathways, MC4R mediates the amplification of signals from the hypothalamo–pituitary–adrenal and hypothalamo–pituitary–thyroid axes. This process permits peripheral information about the status of energy metabolism to be transmitted to the central nervous system. The hypothalamic nuclei then integrate these signals to evoke the appropriate reaction. We found that different sexes exhibited distinct metabolic regulation abilities, likely due to differences in these signalling pathways. MC4R plays a key role in coordinating the afferent messages from the peripheral and regulatory signals by controlling food intake and energy expenditure. To probe the disparities in metabolism and weight regulation between the sexes, we analyzed the expression of MC4R in different tissues from male and female mice by qRT-PCR and immunofluorescence. The results show that the expression of MC4R in brain and kidney is higher in female mice than in male mice, but in the livers, the result is opposition. Additionally, in both sexes, the expression of MC4R is higher in the brain than in the kidneys, and its expression in the liver is lowest, in males, the expression of MC4R in the testis is higher than that in the kidneys. These data show that the expression of MC4R exist different between sexes mice.     

E75、R78和D82是影响大肠埃希氏菌FtsZ自身组装及其与MreB相互作用的重要氨基酸

【目的】探索大肠埃希氏菌Escherichia coli FtsZ突变体FtsZ~(E75A)、FtsZ~(R78G)和FtsZ~(D82A)对FtsZ自身组装和FtsZ-MreB相互作用的影响。【方法】利用常规分子克隆和定点突变技术,构建FtsZ及其突变体表达载体,亲和纯化得到相应的目标蛋白;通过同源重组构建QN6(ftsZ::yfp-cat)、QN7(ftsZ~(E75A)::yfp-cat)、QN8(ftsZ~(R78G)::yfp-cat)和QN9(ftsZ~(D82A)::yfp-cat)菌株;利用活细胞成像技术观察FtsZ及其突变体的胞内定位模式;免疫沉淀和细菌双杂交实验检测FtsZ/FtsZ*-FtsZ*或FtsZ/FtsZ*-MreB间的相互作用;光扫描检测定点突变对FtsZ组装特性的影响。【结果】FtsZ~(E75A)、FtsZ~(R78G)和FtsZ~(D82A)突变体的功能活性降低、各突变体在E.coli内不能正确的定位和形成功能性Z环;FtsZ/FtsZ*-FtsZ*单体间的相互作用减弱或消失,FtsZ*-MreB相互作用破坏;FtsZ突变体体外聚合效率降低。【结论】FtsZ E75、R78和D82是影响FtsZ正确组装和功能及FtsZ-MreB相互作用的重要氨基酸。     

不同种源青檀种子的营养成分及种子活力的差异

以采自安徽（ＡＨ）、山东（ＳＤ）及江苏（ＪＳ）的６个青檀（ＰｔｅｒｏｃｅｌｔｉｓｔａｔａｒｉｎｏｗｉＭａｘｉｍ．）种源种子为材料,测定各种源种子营养成分含量及种子活力。６个种源种子的蛋白质、可溶性糖、淀粉及粗脂肪含量存在较大差异。在种子品质上,６个种源的种子千粒重、浸泡液电导率及简化种子活力指数（ＳＶＩＳ）也存在显著差异。种子中各营养成分含量的高低与ＳＶＩＳ的大小密切相关,复相关系数达０８２２３,以蛋白质含量对ＳＶＩＳ的影响最大,淀粉和粗脂肪含量影响次之,可溶性糖含量影响最小。采用模糊聚类分析法,以种子千粒重、电导率及ＳＶＩＳ为评价指标,可将６个种源的种子品质划分为三大类：第一类包括ＳＤ１、ＡＨ１和ＪＳ１３个种源,种子品质较好;第二类仅为ＡＨ３种源,品质中等;第三类包括ＡＨ２和ＳＤ２２个种源,品质较差。     

核酸疫苗的研究及应用进展

核酸疫苗(DNA疫苗)是20世纪90年代发展起来的一种新型疫苗。核酸疫苗不仅可引起体液免疫反应,而且能诱导高水平的细胞免疫应答,尤其是细胞毒T淋巴细胞(CTL)反应,被认为在病毒、细菌、寄生虫等病原体感染的防治中具有更大的优势。核酸疫苗既可作为病毒、细菌或寄生虫的预防疫苗,也可作为非感染性疾病如肿瘤病的治疗用疫苗。     

混合式教学在面向非生物类学生“生命科学导论”课程中的探索与实践

在“互联网+”时代下,本科教学模式正因信息技术的快速发展发生着变革,线上教学和线下教学相结合的混合式教学模式正在各高校推行和发展。为促进教学模式改革和提升教学效果,本课程组针对面向非生物学专业学生开设的“生命科学导论”通识课程开展了混合式教学改革探索。通过线上线下混合式教学探索和实践,课程集合了高水平大型开放式网络课程(Massive Open Online Course,MOOC)、小班化教学、多元化平台、多维度教学模式等特点,建设了多学科背景的协作式教学团队,形成了重过程重能力的多元评价体系,践行了知识传授与价值引领相结合的育人理念,获得了宝贵的实践经验和良好的教学成效,可为国内高校同类课程的改革建设提供借鉴和参考。混合式教学的开展,拓展了教学的广度和深度,激发了学生的学习兴趣和潜能,开拓了学生的思维和视角,培养了学生的科学素养和综合能力,为创新型复合型人才的培养发挥了积极作用。     

Regulation of ubiquitin-proteasome pathway on pig oocyte meiotic maturation and fertilization

Degradation of proteins mediated by the ubiquitin-proteasome pathway (UPP) plays essential roles in the eukaryotic cell cycle. The main aim of the present study was to analyze the functional roles and regulatory mechanisms of the UPP in pig oocyte meiotic maturation, activation, and early embryo mitosis by drug treatment, Western blot analysis, and confocal microscopy. By using the hypoxanthine-maintained meiotic arrest model, we showed that the meiotic resumption of both cumulus-enclosed oocytes and denuded oocytes was stimulated in a dose- and time-dependent manner by two potent and cell-permeable proteasome inhibitors. Both the mitogen-activated protein kinase (MAPK) kinase inhibitor U0126 and the maturation-promoting factor inhibitor roscovitine overcame the stimulation of germinal vesicle breakdown induced by proteasome inhibitors. The phosphorylation of MAPK and p90rsk and the expression of cyclin B1 increased in a dose- and time-dependent manner when treated with proteasome inhibitors during oocyte in vitro-maturation culture. Both U0126 and roscovitine inhibited the phosphorylation of MAPK and p90rsk, and the synthesis of cyclin B1 stimulated by proteasome inhibitors. When matured oocytes were pretreated with proteasome inhibitors and then fertilized or artificially activated, the second polar body emission and the pronuclear formation were inhibited, and the dephosphorylation of MAPK and p90rsk as well as the degradation of cyclin B1 that should occur after oocyte activation were also inhibited. We also investigated, to our knowledge for the first time, the subcellular localization of 20S proteasome alpha subunits at different stages of oocyte and early embryo development. The 20S proteasome alpha subunits were accumulated in the germinal vesicle, around the condensed chromosomes at prometaphase, with spindle at metaphase I and II, the region between the separating chromosomes, and especially the midbody at anaphase I and telophase I, the pronucleus, and the nucleus in early embryonic cells. In conclusion, our results suggest that the UPP is important at multiple steps of pig oocyte meiosis, fertilization, and early embryonic mitosis and that it may play its roles by regulating cyclin B1 degradation and MAPK/p90rsk phosphorylation.     

Human globin knock-in mice complete fetal-to-adult hemoglobin switching in postnatal development

Elevated levels of fetal γ-globin can cure disorders caused by mutations in the adult β-globin gene. This clinical finding has motivated studies to improve our understanding of hemoglobin switching. Unlike humans, mice do not express a distinct fetal globin. Transgenic mice that contain the human β-globin locus complete their fetal-to-adult hemoglobin switch prior to birth, with human γ-globin predominantly restricted to primitive erythroid cells. We established humanized (100% human hemoglobin) knock-in mice that demonstrate a distinct fetal hemoglobin (HbF) stage, where γ-globin is the dominant globin chain produced during mid- to late gestation. Human γ- and β-globin gene competition is evident around the time of birth, and γ-globin chain production diminishes in postnatal life, with transient production of HbF reticulocytes. Following completion of the γ- to-β-globin switch, adult erythroid cells synthesize low levels of HbF. We conclude that the knock-in globin genes are expressed in a pattern strikingly similar to that in human development, most notably with postnatal resolution of the fetal-to-adult hemoglobin switch. Our findings are consistent with the importance of BCL11A in hemoglobin switching, since removal of intergenic binding sites for BCL11A results in human γ-globin expression in mouse definitive erythroid cells.     

基于模拟退火法由脑磁图推测电流偶极子参数

利用模拟退火（Ｓｉｍｕｌａｔｅｄ Ａｎｎｅａｌｉｎｇ） 算法,由脑磁图（ ＭＥＧ） 数据反演脑内作为磁源的单电流偶极子参数,可以得到理想的结果。在上述工作的基础上,对脑内多电流偶极子参数的反演,则呈现如下状况：即以少于实际源数目的偶极子为源假设反演,目标函数得不到极小优化。反之,目标函数可以得到极小优化, 但出现多余的伪偶极子, 且这些伪偶极子在多次不同条件的反演结果中,处于不稳定状态。若将多次反演结果中处于不稳定状态的偶极子作为伪偶极子的判据而将其排除,则可以得到一种判断磁源偶极子数目的方法     

HPLC-MS/MS shotgun proteomic research of deer antlers with multiparallel protein extraction methods

Deer antlers mature rapidly in 60 days, and subsequently shed in 5 days with rapid ossification. During this procedure, the function of deer antlers changes significantly. Therefore, the profiling of antler proteome is helpful to discover important growing and shedding regulation proteins, which might be of great significance for studying development and regeneration. In this study, a parallel protein extraction strategy was developed to extract proteins from antlers of red deer with five different lysis solutions, followed by shotgun proteomic analysis by microflow reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry (μRPLC-ESI-MS/MS) with a 30 cm-long serially coupled microcolumn. Our experimental results showed that the identified proteins extracted by five kinds of lysis solution were complementary to each other. In total, 416 unique proteins were identified, with relative molecular masses from 2000 to 600,000, and isoelectric points from 3.84 to 11.57. All these results demonstrate that the combination of parallel protein extraction strategy and μRPLC-ESI-MS/MS analysis with serially coupled long microcolumns might be of great significance for comprehensive proteomic research of deer antler.