四种利用不同生境蜥蜴运动能力的形态特征相关性

动物体态特征、功能表现和生境利用之间是否存在相关性是当前生态形态学领域的一个研究焦点。在实验室条件下测定分别利用开阔地面、草丛、岩石、树丛生境的 4种蜥蜴 (中国石龙子、北草蜥、山地麻蜥和变色树蜥 )的形态特征和运动能力 ,着重探讨蜥蜴运动能力与形态特征之间的相关性。 4种蜥蜴的头体长大小依次为 :中国石龙子 >变色树蜥 >北草蜥 >山地麻蜥。就相对体长而言 ,中国石龙子 >山地麻蜥和北草蜥 >变色树蜥 ,而头大小、附肢长度和尾长的种间差异趋势则相反 ;体高的种间差异为北草蜥 >中国石龙子和变色树蜥 >山地麻蜥。在平面上 ,山地麻蜥和北草蜥的速度显著大于中国石龙子和变色树蜥 ;在斜面上 ,变色树蜥和山地麻蜥的速度显著高于中国石龙子。变色树蜥斜面附着能力最强 ,中国石龙子最弱。生境利用不同的蜥蜴形态迥异 ,运动能力亦因此有显著的差异。本研究结果支持动物形态特征与其功能表现相关的观点。     

两种爬行动物胃肠胰系统5-羟色胺细胞的免疫组织化学定位

目的阐明5-羟色胺﹙5-Hydroxytryptamine,﹚细胞在蝘蜓及蓝尾石龙子胃肠胰系统各段的分布及形态学特征.方法应用5-HT-S-P免疫组织化学方法检测消化道及胰腺的5-HT细胞.结果在蝘蜓胃肠胰系统各段均检测出5-HT细胞;而蓝尾石龙子只在消化道各段分布5-HT细胞,胰腺中未发现阳性细胞.5-HT细胞在两种爬行动物消化道都以胃幽门部位分布密度最高,空肠部位分布密度最低,但其分布类型各不相同.两种爬行动物消化道5-HT 细胞的形态多样,从整个消化道看两者大体都有椭圆形、梭形、纺锤形、烧瓶形、楔形、锥形细胞.不同形状5-HT 细胞分布于消化道不同局部,且其组织学分布特点亦有一定差别.蝘蜓胰腺5-HT 细胞散在分布于胰腺腺泡细胞间,呈椭圆形和锥形.结论两种爬行动物胃肠胰系统5-HT细胞的分布及其形态学特征和组织学分布存在着较多共同点,体现了两者消化生理的相同点;同时两种爬行动物胃肠胰系统5-HT细胞的分布型存在着种间差异.     

两种爬行动物胃肠道内分泌细胞的免疫组织化学比较研究

目的研究七种胃肠激素内分泌细胞在多疣壁虎及石龙子胃肠道的定位及分布。应用S-P免疫组织化学方法。方法结果5-羟色胺(5-Hydroxytryptamine,5-HT)细胞在两种爬行动物胃肠道各段均有分布,但分布型各不相同;生长抑素(Somatostatin,SS)细胞仅在多疣壁虎胃贲门至十二指肠段分布,而石龙子胃肠道各段均有分布;胃泌素(Gastrin,Gas)细胞分布于多疣壁虎十二指肠和空肠段,石龙子则仅分布于胃幽门部;胰高血糖素(Glucagon,Glu)细胞和P-物质(Substance P,SP)细胞均分布于多疣壁虎胃中各段,而石龙子胰高血糖素细胞分布于回肠、直肠及胃体处,P-物质细胞则分布于除空肠外的胃肠道各段;胰岛素(Insulin,Ins)细胞和胰多肽(Pancreatic polypeptide,PP)细胞在两种爬行动物胃肠道各段均未检出。结论两种爬行动物胃肠道内分泌细胞的分布既存在着一定共性,体现了两消化生理的共同点;同时也存在着较大的种间差异。     

河南发现刘氏石龙子及该物种系统位置分析

2018年8月下旬,在河南省南阳市桐柏山采集到11号石龙子科（Scincidae）蜥蜴标本。经形态比较鉴定,该批标本均为刘氏石龙子（Pleistiodon liui）,是河南省爬行动物分布新记录种,也是该物种在长江以北地区首次被发现。通过形态学分析,发现刘氏石龙子可能存在雌雄性二态。基于COI基因658 bp序列的系统发育分析显示,大渡石龙子（P. capito）和黄纹石龙子（P. tunganus）聚在一起,然后再与刘氏石龙子聚成一支系,支持先前基于形态数据的黄纹石龙子种组的单系性。     

大壁虎两种群的求偶鸣叫变异

大壁虎Gekko gecko俗称蛤蚧,可分为黑蛤蚧和红蛤蚧.黑蛤蚧主要分布在中国的广东、广西和越南的东北部,而红蛤蚧则主要分布在东南亚地区,包括越南南部、老挝、泰国等.本文对这两种蛤蚧种群的求偶鸣叫进行了定性和定量研究.经比较分析结果表明这两个种群蛤蚧的求偶鸣叫声学特征存在明显差异.大壁虎的求偶鸣叫由一系列的音节组成,可分为3段:第一段由0～5个脉冲串组成,每个脉冲串含多个脉冲(7～10);第二段由4～10个双音节组成;第三段由1～3个单音节组成,只有红蛤蚧的求偶鸣叫具有第三段.此外,黑蛤蚧和红蛤蚧的求偶鸣叫差异也表现在第二段,即双音节的结构上.黑蛤蚧的双音节呈现出复杂的频率调节模式,且第一音节和第二音节之间有明显的沉默间隔.红蛤蚧的求偶鸣叫很少或基本没有频率调节,第一音节和第二音节之间没有沉默间隔.结合这两种蛤蚧在形态、染色体和基因结构方面的显著差异,推测传统认为的大壁虎可能由两个不同的物种以及一个亚种组成.     

蛤蚧视觉神经核团的细胞形态结构及功能的研究

本研究发现,蛤蚧视觉神经核团有视顶盖（OT）、峡核（NI）、基底视束核（nBOR）、豆状核（LM）、中脑深部核（NPM）、圆核（NR）、前背侧室嵴（ADVR）和皮质加厚区（Pth）等,其中NI和ADVR两核团的体积最大。视觉核团中有各种形状的细胞形态,其中梨形和梭形细胞占的比例较大。神经核团的细胞直径为6～30μm,其中以15～28μm最多。在ADVR和Pth核团中有细胞丛簇存在,其它核团尚未发现有这样的结构。各神经核团问和核团内有广泛而复杂的纤维联系。蛤蚧有关视觉神经核团除具有视觉功能外,可能还与听觉、触觉、嗅觉和平衡感觉等功能有关。     

蓝尾石龙子杭州和宁德种群繁殖生活史特征的差异

测定处于不同纬度的浙江杭州和福建宁德的蓝尾石龙子(Eumeceselegans)种群的个体大小和繁殖特征。宁德种群的产卵时间为5月27日—6月22日,早于高纬度杭州种群(6月4日—7月12日)。宁德种群最小繁殖雌体及性成熟个体大小均显著小于杭州种群。宁德和杭州两种群的相对窝卵重无显著差异;当统计去除母体体长的影响之后,两地种群的窝卵数和窝卵重也无显著差异,但杭州种群的卵重量显著大于宁德种群。蓝尾石龙子窝卵数和卵重量呈负相关,窝卵数和卵大小的权衡存在种群间差异。特定窝卵数条件下,杭州种群的卵重量显著大于宁德种群。由此可见,蓝尾石龙子种群间的繁殖生活史特征存在显著差异,而且与母体大小的差异密切相关。推测不同纬度地区的蓝尾石龙子种群的繁殖策略存在差异。     

不同基质对北草蜥和中国石龙子运动表现的影响

动物在野外生境中的活动能力通常会受到许多方面(例如,运动基质表面粗糙程度、遭遇障碍物的大小与形状)的影响。在特定体温(30 ℃)条件下,测量主要分布区重叠的两蜥蜴种类(北草蜥和中国石龙子)在四种不同基质表面(塑料草坪;表面粗糙不透底的塑料地毯;光滑具透底网格的塑料地毯和表面光滑的塑料地毯)的运动表现,以及两者的攀附能力和最大游泳耐力。基质类型显著影响两种蜥蜴的运动表现。两种蜥蜴在粗糙表面运动时的疾跑速明显大于光滑表面(例如,塑料草坪上北草蜥为15.7 SVL/s,中国石龙子为8.1 SVL/s;光滑塑料地毯上则分别为11.4 SVL/s和3.5 SVL/s)。中国石龙子在光滑塑料地毯上具有最大的持续运动距离(10.6 SVL)和最少的停顿次数(1.9次)。北草蜥在光滑塑料地毯上具有最多的停顿次数(4.6次)。两种蜥蜴运动能力的种间差异显著。北草蜥具有较大的相对疾跑速度(北草蜥和中国石龙子:13.5 SVL/s vs 5.8 SVL/s)和攀附能力(143.8 ° vs 101.2 °),但较小的游泳耐力(83.5 s vs 238.5 s)。运动速度与耐力之间存在种间权衡关系而与攀爬能力无进化冲突的结论。     

哺乳动物胰腺体部胰多肽（PP）免疫反应细胞的比较研究

采用SPA-GDN免疫组化染色技术,对人、大鼠、小鼠、豚鼠、猪、狗和猫等七种哺乳动物胰腺体部胰多肽(PP)免疫反应细胞的分布和形态进行比较研究,结果表明,上述七种动物PP细胞的分布和形态有明显的种间差异。人、大鼠和小鼠PP细胞主要位于胰岛周边部,形成环形结构,少量PP细胞散布在外分泌部的腺泡和导管;而豚鼠、猪和猫的PP细胞则主要分布在外分泌部腺泡和导管上皮间;狗的PP细胞在内、外分泌部均有分布。PP细胞的形态在上述动物间也有明显的差异,这可能与该细胞在不同动物的作用途径及功能不同有关。     

蓝尾石龙子杭州和宁德种群繁殖生活史特征的差异

测定处于不同纬度的浙江杭州和福建宁德的蓝尾石龙子(Eumeces elegans)种群的个体大小和繁殖特征。宁德种群的产卵时间为5月27日—6月22日，早于高纬度杭州种群(6月4日—7月12日)。宁德种群最小繁殖雌体及性成熟个体大小均显著小于杭州种群。宁德和杭州两种群的相对窝卵重无显著差异；当统计去除母体体长的影响之后，两地种群的窝卵数和窝卵重也无显著差异，但杭州种群的卵重量显著大于宁德种群。蓝尾石龙子窝卵数和卵重量呈负相关，窝卵数和卵大小的权衡存在种群间差异。特定窝卵数条件下，杭州种群的卵重量显著大于宁德种群。由此可见，蓝尾石龙子种群间的繁殖生活史特征存在显著差异，而且与母体大小的差异密切相关。推测不同纬度地区的蓝尾石龙子种群的繁殖策略存在差异。     

Detection of surface differences between closely related cell populations by partitioning. Cultured K-562 cell sublines

The K-562 cell line is a culture of human leukemia stem cells originally derived from a patient with chronic myelogenous leukemia in blast crisis. We have applied a sensitive method capable of detecting subtle differences in charge-associated and noncharge-related cell surface properties between closely related cell populations to K-562 cells from different sources and having different histories. The method consists of isotopically labeling aliquots of each of two cell populations to be compared with 51Cr-chromate and mixing the labeled cells with an excess of unlabeled cells with which they are to be compared. The mixtures are subjected to countercurrent distribution in either a charge-sensitive or a noncharge-sensitive dextran-poly(ethylene glycol) aqueous two-phase system. The distribution curves are analyzed for total cells (in terms of electronic counts) and labeled cells (in terms of cpm). Alterations in relative specific activities through the distribution curves are indicative of differences in surface properties between such cell populations. Using this method we have found surface differences, both charge-associated and noncharge-related, between any two K-562 cell sublines examined. Interestingly, whereas we observed differences among K-562 sublines, we never witnessed a change in surface properties of the respective sublines. The differences among the sublines examined remained unaltered for more than 40 passages in our hands. It thus appears likely that the event(s) leading to an altered K-562 cell surface, detectable by partitioning, does not occur gradually.     

Differences in the glycosylation of recombinant proteins expressed in HEK and CHO cells

Glycosylation is one of the most common posttranslational modifications of proteins. It has important roles for protein structure, stability and functions. In vivo the glycostructures influence pharmacokinetics and immunogenecity. It is well known that significant differences in glycosylation and glycostructures exist between recombinant proteins expressed in mammalian, yeast and insect cells. However, differences in protein glycosylation between different mammalian cell lines are much less well known. In order to examine differences in glycosylation in mammalian cells we have expressed 12 proteins in the two commonly used cell lines HEK and CHO. The cells were transiently transfected, and the expressed proteins were purified. To identify differences in glycosylation the proteins were analyzed on SDS-PAGE, isoelectric focusing (IEF), mass spectrometry and released glycans on capillary gel electrophoresis (CGE-LIF). For all proteins significant differences in the glycosylation were detected. The proteins migrated differently on SDS-PAGE, had different isoform patterns on IEF, showed different mass peak distributions on mass spectrometry and showed differences in the glycostructures detected in CGE. In order to verify that differences detected were attributed to glycosylation the proteins were treated with deglycosylating enzymes. Although, culture conditions induced minor changes in the glycosylation the major differences were between the two cell lines.     

Distinctive pharmacological differences between liver cancer cell lines HepG2 and Hep3B

As cellular models for in vitro liver cancer and toxicity studies, HepG2 and Hep3B are the two most frequently used liver cancer cell lines. Because of their similarities they are often treated as the same in experimental studies. However, there are many differences that have been largely over-sighted or ignored between them. In this review, we summarize the differences between HepG2 and Hep3B cell lines that can be found in the literature based on PubMed search. We particularly focus on the differential gene expression, differential drug responses (chemosensitivity, cell cycle and growth inhibition, and gene induction), signaling pathways associated with these differences, as well as the factors in governing these differences between HepG2 and Hep3B cell lines. Based on our analyses of the available data, we suggest that neither HBx nor p53 may be the crucial factor to determine the differences between HepG2 and Hep3B cell lines although HBx regulates the expression of the majority of genes that are differentially expressed between HepG2 and Hep3B. Instead, the different maturation stages in cancer development of the original specimen between HepG2 and Hep3B may be responsible for the differences between them. This review provides insight into the molecular mechanisms underlying the differences between HepG2 and Hep3B and help investigators especially the beginners in the areas of liver cancer research and drug metabolism to fully understand, and thus better use and interpret the data from these two cell lines in their studies.     

云南红河和保山两地区小蜜蜂巢房结构比较研究

【目的】本研究旨在对自然环境条件明显不同的云南红河和保山两地区小蜜蜂Apis florea巢房结构进行量化分析,以期揭示这两个地区间小蜜蜂巢房结构的差异性。【方法】测量小蜜蜂子脾厚度、小蜜蜂巢脾上连续10个工蜂巢房的宽度;利用环氧树脂填充巢房,制作巢房模型,基于巢房模型比较两地区小蜜蜂工蜂和雄蜂单个巢房直径、口部边长、棱长、深度和容积及巢房倾斜角的差异。【结果】云南 红河地区小蜜蜂工蜂、雄蜂子脾厚度均极显著小于保山地区的。两地区小蜜蜂连续10个工蜂巢房的宽度在0°方向均显著大于60°和120°方向的宽度,60°和120°方向的宽度之间差异均不显著,两地区小蜜蜂工蜂单个巢房直径在3个方向上也表现出显著差异, 而两地区雄蜂单个巢房的直径在3个方向上均没有显著性差异。红河地区小蜜蜂工蜂巢房直径在3个方向上均显著小于保山地区的,而两地区小蜜蜂雄蜂巢房直径在3个方向上均差异不显著。红河地区小蜜蜂工蜂、雄蜂单个巢房口部边长、棱长、深度和容积均极显著小于保山地区的;两地区工蜂巢房的倾斜角差异不显著。【结论】小蜜蜂巢房的结构存在地区性差异,海拔高、温度低的地区小蜜蜂巢房结构尺寸明显大于海拔低、温度高地区的。本研究结果不仅丰富了小蜜蜂的生物学知识,也为后续研究小蜜蜂巢房结构指标与形态学指标关联性研究提供了思路。     

Cell proliferation, cell death and hepatocarcinogenesis

The carcinogenic process in the liver is a multistep process, characterised by an altered ratio between cell proliferation and cell death. In the last few years, we have undertaken studies aimed at determining the possible differences exhibited by two different types of cell proliferation, namely compensatory regeneration and direct hyperplasia at a molecular and cellular level. These two types of proliferative stimuli appear to play different roles in liver carcinogenesis. The scope of this article is to summarise the present knowledge about the differences in the expression of genes involved in the entry of liver cells into cell cycle, between liver regeneration following cell loss and/or cell death and direct hyperplasia induced by primary mitogens.     

Different baseline sister chromatid exchange levels in density fractionated human lymphocytes

Summary Different activation states of B and T lymphocytes, as manifested by differences in cell density, were obtained by Percoll density centrifugation of unstimulated human lymphocytes. Four different density fractions were defined: B cells with low (1.043 g/ml) and high (1.056) density, and T cells with low (1.067) and high (1.077) density, respectively. Sister chromatid exchange (SCE) conditions and proliferation rates were determined. Total B cells, stimulated by the bacterial mitogen Branhamella, had 4.6 SCE per cell, the lowest mean baseline SCE level recorded among lymphocytes. The growth rate was intermediate between that of low and high density T cells. The two T cell fractions stimulated by phytohemagglutinin (PHA) had different baseline SCE frequencies and different growth characteristics: the low density cells had 5.7 SCEs per cell and a short cell cycle, whereas high density cells had 12.5 SCEs per cell and a longer cell cycle. The differences in baseline SCE frequency and growth characteristics between the two T cell fractions seem to be correlated with the differences in the activation state as reflected by the cell density. Both high and low density T cell are G₀ populations which supposedly differ with respect to previous history in vivo such as age and contact with antigens. The reason why these cells react differently to bromodeoxyuridine (BrdU) is unknown, but differences in intracellular DNA precursor pools and enzyme activities might play a role.     

Exploring cell tropism as a possible contributor to influenza infection severity

Several mechanisms have been proposed to account for the marked increase in severity of human infections with avian compared to human influenza strains, including increased cytokine expression, poor immune response, and differences in target cell receptor affinity. Here, the potential effect of target cell tropism on disease severity is studied using a mathematical model for in-host influenza viral infection in a cell population consisting of two different cell types. The two cell types differ only in their susceptibility to infection and rate of virus production. We show the existence of a parameter regime which is characterized by high viral loads sustained long after the onset of infection. This finding suggests that differences in cell tropism between influenza strains could be sufficient to cause significant differences in viral titer profiles, similar to those observed in infections with certain strains of influenza A virus. The two target cell mathematical model offers good agreement with experimental data from severe influenza infections, as does the usual, single target cell model albeit with biologically unrealistic parameters. Both models predict that while neuraminidase inhibitors and adamantanes are only effective when administered early to treat an uncomplicated seasonal infection, they can be effective against more severe influenza infections even when administered late.     

Lifetime measurements reveal kinetic differences between homophilic cadherin bonds

Cadherins are multidomain adhesion proteins whose interactions direct cell sorting during histogenesis. They determine cell adhesion specificity, but prior studies failed to identify physical differences that could underlie cell sorting. These single molecule studies identify kinetic and strength differences between different cadherins. They further demonstrate that the modular extracellular architecture of cleavage stage C-cadherin supports a multistate binding mechanism. These multiple bonds exhibit a kinetic hierarchy of strengths that map to the different cadherin domains. The outer two N-terminal domains of C-cadherin form two bound states with dissociation rates of 3.9 and 0.02 s(-1). The latter is 25-fold slower than between the corresponding epithelial cadherin segments. In addition to the two fast bonds, the five-domain fragment (CEC1-5) forms two additional stronger, longer-lived bonds with dissociation rates of 0.00039 and 0.00001 s(-1). We further quantified the lifetimes of bonds subject to a constant force, and thus identified multiple dissociation events with rates that agree quantitatively with the force spectroscopy data. The qualitative features are similar to those reported for epithelial cadherin. However, the significant differences in the dissociation rates of the outer domains, which include the specificity-determining region, suggest that kinetic differences may determine cadherin discrimination, rather than adhesion energies.     

Morphometric analysis of the cell outlines of normal and polyomavirus-transformed FR 3T3 fibroblasts

A method is described for the analysis of cell shape, using an image analyzer connected to a computer to assess the cell outline. A series of parameters to assess the contribution of large cytoplasmic expansions to cell morphology and to cell spreading on a planar substratum were used to quantify the visual morphologic differences between normal (nontransformed; N.3T3) and polyomavirus-transformed (Py.3T3) Fisher rat 3T3 fibroblasts. The results show that the Py.3T3 fibroblasts are more spherical than are the N.3T3 fibroblasts and that the cytoplasmic expansions of the Py.3T3 fibroblasts are smaller than those of N.3T3, with the spreading of these two cell strains being different. These differences can be explained by the difference in cell-substratum affinity between these two cell strains.     

HLA-E allelic variants. Correlating differential expression,peptide affinities,crystal structures,and thermal stabilities

Previous studies of HLA-E allelic polymorphism have indicated that balancing selection may be acting to maintain two major alleles in most populations, indicating that a functional difference may exist between the alleles. The alleles differ at only one amino acid position, where an arginine at position 107 in HLA-E*0101 (E(R)) is replaced by a glycine in HLA-E*0103 (E(G)). To investigate possible functional differences, we have undertaken a study of the physical and biochemical properties of these two proteins. By comparing expression levels, we found that whereas steady-state protein levels were similar, the two alleles did in fact differ with respect to cell surface levels. To help explain this difference, we undertook studies of the relative differences in peptide affinity, complex stability, and three-dimensional structure between the alleles. The crystal structures for HLA-E(G) complexed with two distinct peptides were determined, and both were compared with the HLA-E(R) structure. No significant differences in the structure of HLA-E were induced as a result of binding different peptides or by the allelic substitution at position 107. However, there were clear differences in the relative affinity for peptide of each heavy chain, which correlated with and may be explained by differences between their thermal stabilities. These differences were completely consistent with the relative levels of the HLA-E alleles on the cell surface and may indeed correlate with functional differences. This in turn may help explain the apparent balancing selection acting on this locus.