Contraction of fibroblast-containing collagen gels: Initial collagen concentration regulates the degree of contraction and cell survival

Remodeling of extracellular matrix involves a number of steps including the recruitment, accumulation, and eventual apoptosis of parenchymal cells as well as the production, organization, and rearrangement of extracellular matrix produced by these cells. The culture of fibroblasts in three-dimensional gels made of type I collagen has been used as a model of tissue contraction which characterizes both wound repair and fibrosis. The current study was designed to determine the effect of initial collagen concentration on the ability of fibroblasts to contract collagen gels and on cell survival. Native type I collagen was extracted from rat tail tendons and used to prepare collagen gels with varying collagen concentrations (0.75-2.0 mg/ml). Human lung fibroblasts (HFL-1) were cast into the gels and cultured in Dulbecco modified Eagle medium with 0.1% fetal calf serum for 2 wk. The gel size, collagen content, and deoxyribonucleic acid (DNA) content were determined. Gels prepared with an initial concentration of 0.75 mg/ml contracted more rapidly and to a smaller final size than gels prepared from 2 mg/ml initial collagen concentration (final size 7.1 versus 36.4% of initial size, P < 0.01). There was no significant degradation of the collagen in the gels under either condition. Hence, the dramatically increased contraction of the lower density gels resulted in a higher final density (P < 0.01). Cell density was estimated from DNA content. In low initial density gels, the final DNA content was significantly less than that in higher initial density gels (0.73 versus 1.88 microg/gel, P < 0.05). This was accompanied by an increased percentage of apoptotic cells at day 14 (43.3 versus 34.1%, P < 0.05). If the gels were maintained in the attached state which largely prevents contraction, apoptosis was significantly reduced, suggesting that contraction rather than matrix composition was a requirement for the increased apoptosis. In summary, these findings indicate that the initial matrix composition can lead to differing outcomes during fibroblast-mediated wound contraction.     

唐家河自然保护区大熊猫种群数量及栖息地的移动

本文根据大熊猫季节性活动规律特点,应用海拔高度路线调查法,全面收集唐家河自然保护区大熊猫的比较新鲜粪便,计获１２４个粪样材料,提取ＤＮＡ作ＤＮＡ指纹图,经微机检测,保护区有大熊猫３７只,个体数量与粪样采集量之比为１∶３３５１４,有６个家系,雌兽２１只,雄兽１６只。并搞清了保护区生态环境质量,箭竹遭受病虫害的程度,洪水对栖息地的影响,特别对引起大熊猫数量减少及栖息地移动等原因,作了较为详细的分析。     

Spatial-temporal expression of pum1 and pum2 in medaka Oryzias latipes

Two pumilios, pum1 and pum2, were identified in medaka Oryzias latipes. Oryzias latipes pum1 and pum2 are ubiquitous in the adult tissues but with specific expression in the germ cells of gonads, ovary and testis. Pum1 is expressed in the spermatogonia to spermatocytes whilst pum2 presents in spermatocytes of testis only. Oryzias latipes pum1 and pum2 are maternally supplied RNA with ubiquitous expression in the early stages, and embryonic expression of pum1 and pum2 may begin from early gastrula. Both pum1 and pum2 are expressed in the tissues including brain, eye and trunk, and both are expressed in the gonads after hatching. Taken together, Pum1 and Pum2 may play important roles in embryonic and germ cell development of O. latipes.     

半夏属 (PINELLIA)的花粉粒和醇溶蛋白比较

继细胞学 〔1〕、形态学 〔2〕和比较解剖学 〔3〕的研究之后 ,我们又对半夏属的花粉粒和醇溶蛋白作了比较分析 ,旨在探讨这些性状的变异与分类学价值。1 　材料和方法1 .1　实验材料　实验材料采自华东 3省的不同地区。在南京栽植至少 1年后 ,在盛花季节 ( 5月 )选有花植株的花粉和地下块茎作实验分析。各材料的种名、群体编号和产地见表 1。表 1 　供实验用的半夏属 5种植物群体材料的来源Table1　 Sources of material for experiment of the populationsbelonging to5species of Pinellia种名Species群体编号No.of populations产地Lo…     

Mice vaccinated with enteropathogenic Escherichia coli ghosts show significant protection against lethal challenges

Aim: To prepare enteropathogenic Escherichia coli (EPEC) E2348/69 ghosts and investigate whether immunization with EPEC bacterial ghosts can elicit protective immune responses. Methods and Results: A recombinant plasmid with double λPL/PR‐cI857 temperature‐sensitive regulatory cassettes was constructed. The lysis gene E and/or the staphylococcal nuclease A (SNA) gene were separately inserted downstream of the two regulatory cassettes to construct the lysis plasmids pBV220::E and pBV220::E::CI‐P‐SNA. An EPEC reference strain E2348/69 (serotype O127:H6) was transformed with the lysis plasmids to produce EPEC ghosts. Mice injected with bacterial ghosts EGE (EPEC ghosts produced using lysis protein E) or EGES (EPEC ghosts produced using a combination of lysis protein E and SNA) gained weight normally and showed no clinical signs of disease. Vaccination trials showed that mice immunized with EGE or EGES were significantly protected against subsequent challenge with the wild‐type virulent parent strain, EPEC E2348/69 (42/50 and 45/50 survival, respectively); in contrast, none of the 30 control mice survived. Conclusions: Immunization with EPEC ghosts can elicit protective immune responses in BALB/c mice. Significance and Impact of the Study: EPEC ghosts may represent a promising new approach for vaccination against EPEC infection.     

ApCl基因在毕赤酵母中的表达

为了研究ApCl基因的功能,应用基因重组技术将ApCl基因片段克隆入大肠埃希菌—酵母穿梭质拉pGAPZαA,构建重组真核表达质拉pGAPZαA-ApCl,电转化巴斯德单赤酵母GS115,Zeocin筛选出阳性克隆转化子.通过比较转化空载体pGAPZaA和重组载体pGAPZαA-ApCl的不同菌株分别在含有高盐和高山梨醇浓度的液体培养基中生长情况,发现毕赤酵母GS115在转化ApCl基因后其抗旱、抗盐能力显著提高(约3倍),进一步验证了ApCl基因对提高生物抗逆能力有显著作用,为将来分离该蛋白及进一步研究奠定基础.     

非人灵长类基因修饰模型研究进展

非人灵长类动物在生命科学基础研究和生物医药研究领域具有非常重要的地位。近年来随着慢病毒载体转染及靶向核酸酶(ZFN,TALEN,CRISPR/Cas9)等基因操作技术的出现,科学家们成功地获得了外源基因过表达的转基因猴和目的基因定点切割的基因编辑猴。文中对目前利用慢病毒载体获得转基因猴和利用靶向核酸酶获得基因编辑猴的研究进展进行了综述,并讨论了基因修饰猴的嵌合体现象、脱靶现象及非人灵长类动物较长性成熟时间这几个影响非人灵长类基因修饰模型推广应用的因素,最后展望了非人灵长类基因修饰模型构建技术的研究热点及发展趋势。     

Inhibition of mitochondrial complex I improves glucose metabolism independently of AMPK activation

Accumulating evidences showed metformin and berberine, well‐known glucose‐lowering agents, were able to inhibit mitochondrial electron transport chain at complex I. In this study, we aimed to explore the antihyperglycaemic effect of complex I inhibition. Rotenone, amobarbital and gene silence of NDUFA13 were used to inhibit complex I. Intraperitoneal glucose tolerance test and insulin tolerance test were performed in db/db mice. Lactate release and glucose consumption were measured to investigate glucose metabolism in HepG2 hepatocytes and C2C12 myotubes. Glucose output was measured in primary hepatocytes. Compound C and adenoviruses expressing dominant negative AMP‐activated protein kinase (AMPK) α1/2 were exploited to inactivate AMPK pathway. Cellular NAD⁺/NADH ratio was assayed to evaluate energy transforming and redox state. Rotenone ameliorated hyperglycaemia and insulin resistance in db/db mice. It induced glucose consumption and glycolysis and reduced hepatic glucose output. Rotenone also activated AMPK. Furthermore, it remained effective with AMPK inactivation. The enhanced glycolysis and repressed gluconeogenesis correlated with a reduction in cellular NAD⁺/NADH ratio, which resulted from complex I suppression. Amobarbital, another representative complex I inhibitor, stimulated glucose consumption and decreased hepatic glucose output in vitro, too. Similar changes were observed while expression of NDUFA13, a subunit of complex I, was knocked down with gene silencing. These findings reveal mitochondrial complex I emerges as a key drug target for diabetes treatment. Inhibition of complex I improves glucose homoeostasis via non‐AMPK pathway, which may relate to the suppression of the cellular NAD⁺/NADH ratio.     

2010年山东省环境污水中脊髓灰质炎病毒的监测及其基因特征分析

本研究在山东省开展了脊髓灰质炎病毒(Poliovirus,PV)的外环境监测,从济南、临沂两地采集污水标本,浓缩处理后进行病毒分离,对分离到的PV采用中和试验进行血清定型,并对其VP1及3D区进行序列测定,分析其基因突变和重组情况。2010年,共采集污水标本32份,PV阳性10份,阳性率31.3%;分离到18株PV(PV1型3株,PV2型9株,PV3型6株),均为疫苗相关株,VP1完整编码区核苷酸变异数在0~4个之间,在3株PV2型病毒和4株PV3型病毒的基因组中发现重组;对VP1区影响神经毒力的减毒位点分析发现,PV1型病毒中有1株在nt 2 749发生突变(A→G),PV2型病毒中有1株在nt2 908发生A→G突变,3株在nt2 909发生U→C突变,6株PV3型病毒全部在nt2 493发生C→U突变。环境污水中可以分离到PV,其基因重组率和主要减毒位点的回复突变率较高,未发现脊灰野毒株和疫苗衍生株脊灰病毒(Vaccine-derived poliovirus,VDPV)。