两种雀形目鸟类的窝雏数处理实验:检验Lack假说

于 1 997～ 1 999年在位于青海省北部的中国科学院海北高寒草甸生态系统定位站进行。选择地面筑巢的小云雀 ( Alauda gulgula)和灌丛筑巢的黄嘴朱顶雀 ( Acanthis flavirostris)为代表进行窝雏数处理实验。根据 Lack假说的预报检验 ( 1 )常见窝卵数是否是最大生产力窝卵数 ;( 2 )窝雏数处理对雏鸟质量和亲鸟投入是否产生影响 ;( 3)两种鸟的响应方式是否相同。其结果如下 :1小云雀和黄嘴朱顶雀的常见窝卵数分别是 3和 5枚 ,年间变化不明显 ,用幼鸟出飞率作为生产力 ,两种鸟的扩增窝幼鸟出飞率下降 ,常见窝卵数 (分布频率最高 )等同于最大生产力窝卵数 ;2小云雀的幼鸟的生长参数不随窝雏数的改变而变化 ,而黄嘴朱顶雀有明显变化 ,说明窝雏数处理对后者幼鸟质量有明显影响。 3用递食率作为亲鸟投资指标 ,小云雀亲鸟的递食率随窝雏数的增加而增加 ,但雏期不变 ;而黄嘴朱顶雀递食率不变 ,但雏期延长。 4扩增窝雏数后 ,两种亲鸟表现出不同的响应方式 ,小云雀表现为提高单位时间递食次数 ,而黄嘴朱顶雀延长育幼时间。这两种方式不是通过影响雏鸟质量就是通过影响亲鸟存活率来降低子代和亲代的适合度。结果支持了自然选择将窝卵数调节到亲鸟能喂活最大数量子代的限度 ,即常见窝卵数就是最大生产力窝卵数的 Lack?

我国山丘疫区杜氏利什曼原虫LACK保护性抗原基因克隆和序列分析

利什曼原虫的LACK抗原是利什曼原虫的蛋白激酶C受体的同源物 ,是新发现的一种抗原蛋白。本实验用分子克隆的方法获得我国山丘疫区杜氏利什曼原虫编码LACK保护性抗原的基因片段 ,测序并对其序列分析比较。我国山丘疫区杜氏利什曼原虫 (L dSC10 )LACK抗原基因片段的大小为 94 2bp ,与GenBank中LACK的核苷酸序列一致性在 94 %以上 ,呈高度同源性 ;推导的氨基酸序列与GenBank中LACK的氨基酸序列一致性达 95 %以上 ,具有高度保守性 ;该蛋白质属于WD蛋白家族 ,有重要的生物学意义。

杜氏利什曼原虫LACK抗原基因的克隆和表达

目的 在大肠杆菌中高效表达纯化杜氏利什曼原虫的LACK抗原。方法 以本实验室的重组质粒T -LACK为模板 ,PCR扩增得到LACK抗原基因 ,与表达载体pQE31定向重组 ,转化到宿主菌M 15中进行表达和纯化 ,并以SDS -PAGE和Western -blotting进行鉴定。结果 1 SDS -PAGE电泳检测 ,重组质粒 pQE31-LACK的全菌蛋白没有出现明显的特异表达带 ,而纯化蛋白和包涵体溶解物在 36kDa处均出现了特异的表达带。 2 36kDa的纯化蛋白被抗利什曼原虫鼠血清清晰地识别。结论 得到了高效表达的LACK纯化蛋白 。

杜氏利什曼原虫LACK基因真核表达重组质粒及其在真核细胞中的表达

利什曼原虫的 L ACK抗原是利什曼原虫活性蛋白激酶 C受体同源物 ,是一种新发现的抗原蛋白。我们以本实验室的重组质粒 T- L ACK为模板 ,PCR扩增获得 L ACK基因 ,与真核表达载体 pc DNA3.1(+)定向重组 ,重组质粒经酶切和 PCR分析 ,含有约 95 0 bp的 L ACK基因 ,成功构建含有 L ACK基因的真核表达重组质粒 pc D-NA3- L ACK。将此重组质粒转染 COS- 7细胞 ,通过 RT- PCR及免疫荧光检测 L ACK基因在真核细胞中的表达。实验结果显示转染了重组质粒的 COS- 7细胞 ,其 RT- PCR及免疫荧光检测均呈阳性反应 ,证实重组质粒 pc DNA3-L ACK能在 COS- 7细胞中有效表达 L ACK蛋白。

线性测量误差模型的lack-of-fit检验

基于正态假设 ,提出了测量误差模型lack of fit检验的一种方法 .在原假设下 ,检验统计量渐近服从 χ2 分布 .还就该检验的势函数与权函数的选择进行了讨论 。

杜氏利什曼原虫平原和荒漠疫区分离株LACK基因克隆及序列分析

目的 测定我国平原疫区和荒漠疫区杜氏利什曼原虫分离株活性蛋白激酶 C受体同源物 (L ACK)基因序列 ,并与山丘疫区分离株及国外利什曼原虫分离株进行比较。 方法 应用 RT- PCR扩增 L ACK基因 ,将其克隆入p UC18载体后用双脱氧链末端终止法测序 ,并与 Gen Bank中相关数据进行比较。 结果 用 RT- PCR成功扩增出约95 0 bp的 L ACK基因片段 ,测序结果表明其片段大小均为 94 2 bp,与 Gen Bank中多种利什曼原虫 L ACK基因的核苷酸序列一致性达 97%以上。我国山丘、平原和荒漠 3个不同疫区杜氏利什曼原虫分离株的 L ACK基因序列的一致性达95 %以上。 结论 获得了我国平原和荒漠疫区杜氏利什曼原虫 L ACK基因序列。我国 3个不同疫区杜氏利什曼原虫分离株的 L ACK基因具有高度同源性。

Life Loss Estimation Based on Dam-Break Flood Uncertainties and Lack of Information in Mountainous Regions of Western China

Compared with urban floods, dam-break floods are associated with greater uncertainties, including variable dam-break modes and hydrological characteristics, so conventional flood estimation methods cannot be directly applied in the estimation of dam-break flood loss. In particular, there is scant information regarding the conditions of affected area and hydrological characteristics in southwest China. In this paper, we introduce an integrated model for estimating flood loss that is adapted to the mountainous regions of southwestern China in light of the relative lack of available information. This model has three major components: a basic information model, a dam-routed flood propagation simulation model, and a loss estimation model. We established the basic information model despite the relative lack of available information using 3S technology [remote sensing(RS); geographical information system(GIS); global positioning system(GPS)], data mining technology, and statistical analysis techniques. Our dam-routed flood propagation simulation model consists of major hydrologic processes and their governing equations for flow propagation, which we solve using finite-difference schemes. In this model, the flood propagation area is divided into grids and each grid is determined by the characteristic parameters obtained from the propagationsimulation. We present a case study of the Lianghekou hydropower station in Sichuan Province, China to illustrate the practical application of this integrated model for life loss estimation.

Research on the lack of alloying in the galvannealed coating of automotive sheet steel

Samples of the cross section microstructures of galvannealed steel sheets that lack alloying were analyzed. X-ray diffraction （XRD） tests were carried out. The study discovers that the deficit of alloying was higher on both sides of the steel sheet when compared to the center and the thickness of the coating on the sides was also higher than the center. The results of the XRD tests demonstrate that the microstructure of the coating with a lack of alloy is mainly composed of zinc,ζ and δ. They also indicate that the lack of alloying is mainly due to a lower galvannealing temperature and thicker coating. It is shown by the optical micrographs of coating that the δ phase forms first in a discontinuous manner at the interface and then rapidly pushes towards the coating and enlarges.

Lack of association between cellular repressor of E1A-stimulated genes(GREG)polymorphisms and coronary artery disease in the Han population of North China

Objectives Phenotypic switching of smooth muscle cells(SMCs) plays a critical role in the pathogenesis of atherosclerotic lesions such as coronary artery disease (CAD).Accumulating evidence demonstrates(hat a cellular repressor of E1A-stimulated genes(CREG) plays a role in the maintenance of the mature phenotype of vascular SMCs. The purpose of the present study was to assess the possible association between CREG and CAD in the Han population of North China.Methods The promoter region of CREG by direct sequencing was conducted in 48 subjects.Then SNP rs2995073 and another 4 tagSNPs(rs4657669,rs3767443, rsl6859185,rs3753921) were selected for the association study.All five selected SNPs were determined in 1161 patients with angiographically proven CAD and 960 controls with normal coronary angiograms to investigate the possible involvement of CREG in CAD.Results Genotype frequencies of the five examined polymorphisms were similarly distributed between CAD group and controls(P】0.05).Further haplotype analysis also found no significant differences in the distributions between CAD group and controls(P】0.05). Conclusions This study did not show an association between common variants of CREG and CAD in the northern Chinese Han population.

EFFECTS OF QUERCETIN ON MEMBRANE FLUIDITY OF INJURED VASCULAR ENDOTHELIAL CELLS WITH HYPOXIA AND THE LACK OF GLUCOSE

Objective To study the effects of different concentrations of Quercetin on nitric oxide (NO) production and membrane fluidity of the injured human umbilical vein vascular endothelial cell line(ECV 304) with hypoxia and the lack of glucose. Methods The experiments were performed in the culture of ECV 304 injured with hypoxia and the lack of glucose in vitro. The releases of intracellular lactate dehydrogenase(LDH) of ECV 304 was measured with automatic biochemistry analysis. NO level of ECV 304 was monitored with colorimetry. The membrane fluidity of ECV 304 was measured with the fluorescence polarization method. Results After ECV 304 was cultured in hypoxia and the the lack of glucose for 24 hours, the release of LDH and the membrane fluidity were increased significantly; NO level was decreased. Preincubation of ECV 304 with 20, 80,160 μ mol·L -1 of Quercetin for 24 hours reduced LDH activity, membrane fluidity and increased the level of NO in hypoxia and the lack of glucose induced ECV 304. Conclusion These results demonstrate that Quercetin can produce the protective effect on hypoxia and the lack of glucose induced injury of ECV 304 by increasing release of NO and changing membrane fluidity.

Migrant Workers' Lack of Cultural Rights and Interests and Government Safeguard Measures

This paper analyses the status quo of migrant workers' lack of cultural rights and interests as follows:the holistic cultural life of migrant workers is scant and monotonous;the cultural facilities provided by the majority of enterprises are critically short;the cultural life of migrant workers has the characteristic of closeness to some extent;the holistic cultural consuming capacity of migrant workers is very low,and they are not satisfied with their own cultural life.This paper puts forward the measures that the government should adopt to make up for the lack of migrant workers' cultural rights and interests as follows:first,it should eliminate discrimination in terms of system,and incorporate migrant workers' cultural rights and interests into the building scope of urban public culture;second,it should establish a variety of free public culture facilities,to adapt to the needs of migrant workers;third,it should formulate various kinds of laws and regulations,to effectively safeguard migrant workers' cultural rights and interests.

Lack of proper reimbursement is hampering adoption of minimally invasive gastrointestinal endoscopy in North America

Endoscopic submucosal dissection(ESD)and related procedures are minimally invasive and cost-effective alternates to surgery.However,there is no approved or listed current procedural terminology(CPT)for ESD.We aimed to review the current reimbursement process hurdles for ESD procedures in private practice model in United States.We reviewed the data of two advanced endoscopists(one in New York and other in Pennsylvania State)performing ESD in their private practice set-ups.We found the reimbursement process was complex,with number of refusals varied from 0-9 for ESD procedures.It was not paid at all in 8.3%of cases by the medical insurance.Endoscopic mucosal resection,which is considered inferior as compared to ESD,but has a listed CPT,was denied in only 0.83%cases.Our data highlights the billing hurdles by the endoscopists to adopt ESD-related procedures in private practice model.

Development of a Method to Produce Chromosome Lacking Lines (CLLs) in <i>Nicotiana tabacum</i>L. “Red Russian”

Monosomic lines of Nicotiana tabacum are helpful to confirm the location of genes on specific chromosomes. In the cross N. nudicaulis and N. tabacum, hybrid seedlings express lethal symptoms, which are controlled by the S subgenome of N. tabacum. To identify the responsible chromosome, we needed to produce chromosome lacking lines (CLLs) of N. tabacum L. “Red Russian” and use them to cross with N. nudicaulis. From a cross of (N. tabacum × N. tomentosiformis) × N. tabacum, 380 BC1 individuals were obtained. Using a Haplo-Q line (a monosomic line lacking the single linkage group 11) and N. tabacum, we found that qPCR is a simple and reliable screening method for CLLs of N. tabacum. The marker PT30342 is located on linkage group 11, and the -Ct value (Ct Actin - Ct PT30342) was 2.0 for a disomic line and was 1.097 for a Haplo-Q line. By the use of flow cytometry, qPCR and chromosome counting together as a screening method, we identified 6 CLLs lacking 2 to 6 chromosomes. Compared with conventional methods, our method is a rapid technique for making and screening CLLs ofthe S or S/T subgenome of N. tabacum. Further, these CLLs will be useful to identify the location of two or more factors on chromosomes controlling a variety of genetic problems affecting breeding. Here, we only made CLLs of the S or S/T subgenome of N. tabacum. We will use the method established in this study to produce CLLs of the T subgenome of N. tabacum, and gather a full set of CLLs of N. tabacum. qPCR could also be applied to the identification of chromosome aberrations in other plants.

Lack of Association between Genetic Polymorphisms Affecting Autonomic Activity and Coronary Artery Spasm

Coronary artery spasm （CAS） is one of the leading pathological causes of a wide spectrum of ischemic heart diseases, ranging from variant angina pectoris to acute myocardial infarction and even sudden cardiac death[1]. Furthermore, Pierron et al. concluded that CAS of angiographically normal or sub-normal arteries is responsible for death or myocardial infarction in 11.6% of all cases. Oddly, the incidence of CAS is remarkably higher in Asians than in Caucasians[3], suggesting genetic involvement In its pathogenesis.

Ethanolic Extract of <i>Nigella sativa</i>Seeds Lacks the Chemopreventive Efficacy in the Post Initiation Phase of DMH-Induced Colon Cancer in a Rat Model

Nigella sativa, belonging to the Ranunculacea family, is a versatile phytochemical mine bestowed with multi-dimensional medicinal effects. The current study was performed to investigate the chemopreventive efficacy, if any, of the ethanolic extract of indigenous Nigella sativa seeds (ENS) and to evaluate its potentials on tumor progression during the initiation and post initiation phases of Dimethylhydrazine-induced colon carcinogenesis in a rat model. ENS treatment during the initiation phase unveiled chemopreventive effect manifested by significant reductions in tumor incidence, multiplicity and tumor volumes. Histopathological findings and modified Duke’s classification of tumors provided evidence that ENS, administered in the initiation phase, is capable of delaying progression, restricting invasion and attenuating aggressiveness of colon tumors. These results imply that ENS may be a promising candidate in the primary prevention of colon cancer. On the contrary, we demonstrated that ENS lacked chemopreventive and tumorigenesis inhibitory effects in the post initiation phase. We speculate that the chemopreventive effect of ENS might be due to the synergistic actions of various constituents present in the extract. However, extensive studies are warranted and more efforts need to be dedicated to fractionate, analyze and to further appraise the anticancer effect of ENS before any definitive conclusions can be drawn.

Beijing Lack of "Carrier"Exhibition Center

An Interview towards Mr. Chu Xiangyin, Vice Chairman of Beijing Subcouncil, CCPIT Reporter: Would you please tell us development of exhibition industry in Beijing? Chu Xiangyin: Beijing Statistical Bureau and us have been designing and analyzing statistical system for exhibition industry from 2003. As the largest exhibition center in Beijing,

No More Free Rides-Rational Policy or Lack of Empathy?

By taking advantage of their senior citizen card, elderly residents in Shanghai over 70 used to be able to take the bus and the subway for free, but this favorable policy was discontinued on June 25. Instead, starting from the same month, senior Shanghai citizens - over 65 and with permanent residency - were eligible for a new monthly subsidy ranging from 75 to 600 yuan （$11-90）, according to different age groups.

How Harmful a Lack of Sleeping Is to Your Health

词数:356阅读难度:建议阅读时间:4分钟Through his work,he’s determined that people who don’t get enough sleep tend to be less healthy and have lower energy levels than those who get the recommended amount of shut eye per night.After analyzing the results of 20 separate studies,he’s found a strong correlation between how much people sleep and how