Molecular signatures of cell migration in C. elegans Q neuroblasts

Metazoan cell movement has been studied extensively in vitro, but cell migration in living animals is much less well understood. In this report, we have studied the Caenorhabditis elegans Q neuroblast lineage during larval development, developing live animal imaging methods for following neuroblast migration with single cell resolution. We find that each of the Q descendants migrates at different speeds and for distinct distances. By quantitative green fluorescent protein imaging, we find that Q descendants that migrate faster and longer than their sisters up-regulate protein levels of MIG-2, a Rho family guanosine triphosphatase, and/or down-regulate INA-1, an integrin α subunit, during migration. We also show that Q neuroblasts bearing mutations in either MIG-2 or INA-1 migrate at reduced speeds. The migration defect of the mig-2 mutants, but not ina-1, appears to result from a lack of persistent polarization in the direction of cell migration. Thus, MIG-2 and INA-1 function distinctly to control Q neuroblast migration in living C. elegans.     

Genome Rearrangements Caused by Depletion of Essential DNA Replication Proteins in Saccharomyces cerevisiae

Genetic screens of the collection of ～4500 deletion mutants in Saccharomyces cerevisiae have identified the cohort of nonessential genes that promote maintenance of genome integrity. Here we probe the role of essential genes needed for genome stability. To this end, we screened 217 tetracycline-regulated promoter alleles of essential genes and identified 47 genes whose depletion results in spontaneous DNA damage. We further showed that 92 of these 217 essential genes have a role in suppressing chromosome rearrangements. We identified a core set of 15 genes involved in DNA replication that are critical in preventing both spontaneous DNA damage and genome rearrangements. Mapping, classification, and analysis of rearrangement breakpoints indicated that yeast fragile sites, Ty retrotransposons, tRNA genes, early origins of replication, and replication termination sites are common features at breakpoints when essential replication genes that suppress chromosome rearrangements are downregulated. We propose mechanisms by which depletion of essential replication proteins can lead to double-stranded DNA breaks near these features, which are subsequently repaired by homologous recombination at repeated elements.     

An improved on-line solid phase extraction coupled HPLC–MS/MS system for quantification of Sifuvirtide in human plasma

An improved liquid chromatographic method with on-line solid phase extraction (SPE) and tandem mass spectrometric detection was optimised for quantification of the anti-HIV peptide Sifuvirtide in human plasma. The SPE sorbents, loading buffer composition and other aspects of the on-line SPE column were investigated in detail for efficiently extracting the interesting peptides and simultaneously discarding the large amount of proteins. The gradient elution program was optimised on the analysis column to decrease the matrix effect and obtain excellent selectivity. The multiple charge ion at m/z 946.4 of Sifuvirtide was quantified by a linear ion trap mass spectrometer, operating in the positive mode, and selective reaction monitoring (SRM) acquisition. Method validation results demonstrated that the linear calibration curve covered a range of 6.1–6250 ng/mL, and the correlation coefficients (r²) were above 0.992. The lower limit of detection (LLOD) with a signal-to-noise (S/N) ratio higher than 10 was 6.1 ng/mL. The accuracy ranged from −7.6 to 10.6%, and the intra- and inter-batch precisions were less than 8.7% and 5.5%, respectively. Finally, more than nine hundred of samples from a clinical trial was completely analyzed using this on-line SPE coupled HPLC–MS/MS system in one single week, due to the rapid run-time of individual sample (6.5 min).     

中国96个荔枝种质资源的EST-SSR遗传多样性分析

根据本实验室已获得的荔枝果皮cDNA文库EST序列,通过SSRIT在线检索,从3391条EST序列中,发现305条含有SSR,占整个文库EST的8.99%。利用SSR-ESTs序列共设计100对EST-SSR引物,其中62对在荔枝上有扩增产物,50对有扩增多态性,即具有一定的通用性。接着从96份荔枝种质中选取12个品种的基因组DNA,开展核心引物筛选,共筛选出多态性较好的EST-SSR分子标记30个;这30个EST-SSR分子标记在96份资源共扩出284条带,不同引物的扩增条带在3～18条之间,平均9.47条,其中有282条为多态性带,多态率高达99.30%,每对引物的Nei's基因多样度范围为0.186～0.396,香农信息指数范围为0.318～0.558;此外,系统聚类分析结果表明,在相似系数0.5525处,可将96份荔枝种质资源分成了8大类群,该8大类群基本与其生态类型和植物学性状特征相符。在此基础上,还对荔枝的主栽品种和特殊种质进行鉴别,结果表明,该30个EST-SSR分子标记在不同品种间可产生较清晰可辨的多态性差异,为荔枝品种以及种质资源鉴别和鉴定的分子指纹的构建奠定了良好基础。     

Garlic accelerates red blood cell turnover and splenic erythropoietic gene expression in mice: evidence for erythropoietin-independent erythropoiesis

Garlic (Allium sativum) has been valued in many cultures both for its health effects and as a culinary flavor enhancer. Garlic's chemical complexity is widely thought to be the source of its many health benefits, which include, but are not limited to, anti-platelet, procirculatory, anti-inflammatory, anti-apoptotic, neuro-protective, and anti-cancer effects. While a growing body of scientific evidence strongly upholds the herb's broad and potent capacity to influence health, the common mechanisms underlying these diverse effects remain disjointed and relatively poorly understood. We adopted a phenotype-driven approach to investigate the effects of garlic in a mouse model. We examined RBC indices and morphologies, spleen histochemistry, RBC half-lives and gene expression profiles, followed up by qPCR and immunoblot validation. The RBCs of garlic-fed mice register shorter half-lives than the control. But they have normal blood chemistry and RBC indices. Their spleens manifest increased heme oxygenase 1, higher levels of iron and bilirubin, and presumably higher CO, a pleiotropic gasotransmitter. Heat shock genes and those critical for erythropoiesis are elevated in spleens but not in bone marrow. The garlic-fed mice have lower plasma erythropoietin than the controls, however. Chronic exposure to CO of mice on garlic-free diet was sufficient to cause increased RBC indices but again with a lower plasma erythropoietin level than air-treated controls. Furthermore, dietary garlic supplementation and CO treatment showed additive effects on reducing plasma erythropoietin levels in mice. Thus, garlic consumption not only causes increased energy demand from the faster RBC turnover but also increases the production of CO, which in turn stimulates splenic erythropoiesis by an erythropoietin-independent mechanism, thus completing the sequence of feedback regulation for RBC metabolism. Being a pleiotropic gasotransmitter, CO may be a second messenger for garlic's other physiological effects.     

东北地区野生百合数量分类研究

对中国东北地区6种3变种30份野生百合的23个形态性状进行了研究。结果表明,我国东北地区野生百合种质资源的主要数量性状均有明显差异,其中花柱长和叶宽的变异系数较大,分别为59.49%和54.03%。基于形态性状,把30份野生百合聚类并划分为两大类:第1类为茎粗壮、花朵较大的种类,包括卷丹和毛百合;第2类为花朵相对较小的种类,包括有斑百合、大花百合、细叶百合、垂花百合、大花卷丹、东北百合和朝鲜百合。通过主成分分析,前4个主成分代表了形态分化的82.51%,即叶长和宽、外轮花瓣宽、内轮花瓣长和宽、花蕾长、花柱长、花药长8个性状是其形态分化的主要指标。     

布地奈德雾化吸入治疗特发性肺纤维化临床研究的系统评价

目的:探讨布地奈德雾化吸入治疗特发性肺纤维化的有效性和安全性.方法:检索包括中国生物医学文献数据库,中国期刊全文数据库,中文科技期刊数据库和万方数据资源系统.收集2009年4月以前发表的布地奈德雾化吸入治疗特发性肺纤维化的随机对照研究.纳入研究的质量评价参考Cochrane干预性研究系统评价员手册,采用RevMan4.2分析数据.结果:6个关于布地奈德雾化吸入治疗特发性肺纤维化的随机对照研究纳入评价,纳入特发性肺纤维化患者260例(试验组/对照组:132/128),纳入研究质量较低.对同质性好的数据进行meta分析,结果表明布地奈德雾化吸入治疗特发性肺纤维化能改善患者的呼吸困难等症状,改善肺功能,氧分压,疗效与口服泼尼松(龙)组相当.且布地奈德雾化吸入方式不良反应较少,表现为口腔炎及血糖高,其不良反应明显低于口服泼尼松(龙)组,患者依从性较好.结论:纳入研究的方法学质量普遍较低,存在多种偏倚,影响了结果的可靠性.有必要开展设计严谨、管理规范的临床研究以进一步证实布地奈德雾化吸入治疗特发性肺纤维化的有效性和安全性,为临床决策提供高质量的疗效证据.     

高浓度葡萄糖对小鼠囊胚Caspase-8表达的影响

目的:探讨高浓度葡萄糖对小鼠囊胚Caspase-8表达的影响.方法:通过促超排卵,获取妊娠3.5d小鼠囊胚,随机分成三组,即对照组(空白)、低糖组(葡萄糖浓度为7.5mmol/L)和高糖组(葡萄糖浓度为28.0mmol/L),分别培养在含0、7.5mmol/L和28.0mmol/L葡萄糖的M199培养基中,培养24h后,然后再吸出囊胚.每组随机吸取30个囊胚用免疫组织化学S-P法.检测不同浓度葡萄糖对小鼠囊胚Caspase-8表达状况,利用HPIAS-1000图像分析系统测定Caspase-8在以上三组中表达的平均光密度和平均阳性面积率.结果:Caspase-8表达结果:空白组中囊胚细胞胞浆中可见少量浅棕黄色颗粒,Caspase-8表达呈弱阳性.低糖组中囊胚细胞胞浆未见着色,Caspase-8表达呈阴性.高糖组囊胚细胞胞浆中可见较多的棕黄色颗粒,Caspase-8表达呈强阳性.空白组与低糖组囊胚Caspase-8表达的阳性面积率及平均光密度无显著性差异(P>0.05),高糖组与空白组和低糖组相比均存在显著性差异(P<0.01).结论:高浓度葡萄糖可诱导Caspase-8的过度表达,导致囊胚细胞数目过度减少,从而影响囊胚的正常发育和着床.     

IL-18及γ-IFN与过敏性皮炎患者的相关性研究

目的:探讨血清IL-18和γ-IFN水平及IL-18编码基因-137G/C、-607C/A多态性与过敏性皮炎的相关性.方法:提取受试者白细胞DNA,等位基因特异性引物PCR技术检测28例过敏性皮炎病人和52例正常对照IL-18基因多态性;酶联免疫吸附法(ELISA)检测两组IL-18和γ-IFN血清含量.结果:过敏性皮炎组与对照组比较,两者-137G/C、-607C/A基因型频率和等位基因频率均无显著性差异(P＞0.05).过敏性皮炎组的血清IL-18和γ-IFN水平明显低于对照组,差异有显著性(P＜0.001).不同基因型皮炎组患者间的血清IL-18水平均无统计学差异(P＞0.05).结论:过敏性皮炎患者IL-18和γ-IFN的表达降低,提示过敏性皮炎的发生可能与本身血清IL-18和γ-IFN水平低下有关.