南京1号直立人头骨与肯尼亚KNM-ER 3733人类头骨化石的形态比较

KNM-ER 3733人类头骨化石的年代为距今1.78百万年,1975年发现于肯尼亚。Walker和Leakey注意到这具头骨与周口店直立人的在脑颅形态上很相近,但二者在年代上相差大约1百万年,故认为直立人形态在这1百万年期间是稳定的。长期来此观点缺乏更多的人类化石证据来支持。1993年在中国发现了南京1号人类头骨化石。该头骨与KNM-ER 3733头骨一样兼具脑颅和面颅,且都属于成年女性个体,但南京1号人类头骨化石的年代比KNM-ER 3733人类头骨化石的要晚大约1百万年。因此,南京1号人类头骨是目前所知的可用来验证直立人头骨形态是否在1百万年期间保持稳定的唯一合适的人类头骨化石材料。形态比较表明,这两个人类头骨化石的脑颅虽然在眶上圆枕上沟的发育程度、眶后收缩的程度、额骨横向隆起的程度、角圆枕和乳后突的发育与否、顶骨形状以及骨壁厚度的表现上有所差异,但有更多的形态性状显示出相近。这些相近表现在脑颅的长、宽、高值上;颅容量上;脑颅的低矮性上;脑颅最大宽之位置上;额骨、顶骨、枕骨之矢弧值的比例上;眶上圆枕的纤细上;顶骨的大小和矢向扁平性上;颞线位置和颞鳞顶缘的形状上;枕鳞的低宽形状上;上枕鳞与下枕鳞之间的转折形状和比例上;枕骨圆枕和枕骨圆枕上沟的发育程度上等。这两具头骨的面颅虽然有同属突颌型的面角、皆发育有鼻骨间嵴、两鼻骨组成的上部宽度与下部宽度皆差别很大,但有更多的形态性状显示出差别。这些差别表现在面型上、颜面上部扁平度上、眶形和眶型上、上颌额突外侧面的朝向上、鼻骨横向隆起程度上、鼻梁外突程度上、鼻型上、颧骨下缘外展程度上、颊高上、颧上颌下缘的形状上、上颌颧突基部的位置上以及颧结节的位置上等。因此,南京1号头骨与KNM-ER 3733头骨之间在脑颅上显示出较多的相近性状,在面颅上则显示出较多的相异性状。脑颅方面的相近性状大多具有分类上的鉴别价值。这两个头骨脑颅形态的相近支持把KNM-ER 3733头骨鉴定为"直立人"的观点;也提示了南京1号头骨的脑颅似乎保持着1百多万年前的"祖先"形态。如果直立人的某些成员在至少1百万年期间保持着形态稳定的话,则这种形态上的稳定主要是表现在脑颅形态上。这两具头骨的面颅形态上较大差异的意义,目前尚不清楚。     

中更新世非洲Bodo人类头骨化石与周口店直立人的比较--中国与非洲人类头骨特征对比之三

发现于埃塞俄比亚MiddleAwash地区Bodo地点距今60万年的人类头骨化石是迄今发现的最为古老和完整的非洲中更新世人类化石。由于Bodo头骨化石在形态特征上兼有直立人与智人的特点,多年来学术界对其分类地位一直存在争议。Rightmire认为Bodo头骨化石与BrokenHill及Petralona等在分类上属于古老型智人的中更新世人类更为接近,是非洲直立人向古老型智人过渡的代表。至少在距今60万年的中更新世早期直立人向古老型智人转变的成种事件在非洲就已经发生。以Bodo头骨为代表的一批更新世中期非洲和欧洲人类化石构成了可能是后期人类祖先的人属海德堡种。这些观点导致了近年学术界对古老型智人在非洲及欧亚出现时间以及更新世中期非洲和欧亚地区古人类相互之间演化关系的关注。基于这样的背景,本文对年代与Bodo化石接近的周口店直立人头骨特征与Bodo头骨的相似及差异表现情况进行了对比研究。结果发现Bodo头骨在一系列特征上与周口店直立人相似,同时在包括颅容量在内的其它一些特征上呈现出后期智人的特点,但总体形态上似乎与直立人更为相似。作者认为尽管这种进化上的镶嵌现象在中国古人类化石记录上也广泛存在,但由于中国人类化石标本在年代上的不确定性,目前还没有可靠的证据说明这种集直立人与智人化石特征为一体的镶嵌性在中国古人类化石出现的时间接近或早于非洲。考虑到中国与非洲直立人生存年代的巨大差异及人类演化的不同步或地区间差异,具有较多后期人类特征表现的人类首先出现在非洲是完全可能的。根据这些研究对比,作者就人类演化的镶嵌现象、更新世中期非洲与亚洲地区人类演化上的差异等问题进行了讨论。     

南京2号人类头骨化石的复位和形态

南京2号人类头骨化石仅保留部分的额骨、顶骨、枕骨和颞骨,为一不完整的颅盖骨。其顶骨和枕骨有数条断裂缝,各断块之间有程度不一的错动,致使该颅盖骨显得外形异常。本项研究是对该颅盖骨的错动部分进行复位,结果表明,南京2号头骨有较大的顶骨、较小的上枕鳞相对宽度、可能较大的颅容量。这些形态提示该头骨与直立人有所不同而与早期智人相近。该头骨所具有的角圆枕、颞鳞顶缘形状、枕骨圆枕发育程度、枕骨的枕平面与项平面过渡情况、枕内隆突点与枕外隆突点的距离、头骨骨壁厚度、脑膜中动脉分支情况、头骨枕面观之轮廓线样式等形态细节,还很难作为可靠的依据把南京2号头骨鉴定为直立人。南京2号头骨很大可能是属于智人亚种(Homo sapiens sapiens)中的一员。     

南京人头骨化石研究新进展

1 993年在南京汤山葫芦洞发现了2具人类头骨化石-南京1号头骨和南京2号头骨.这2具头骨化石先后经过两次研究都被认为是属于直立人.近几年来,对南京人类头骨化石作了更深入的研究,研究涉及的内容可归纳为:1)对南京2号头骨作了复位和复原、进行了重新鉴定.对南京1号头骨作了颅容量计算;2)对南京1号头骨作了更广泛的比较,对比标本包括周口店直立人头骨、印尼Sangiran 17直立人头骨、肯尼亚KNM-ER3733头骨和东非Bodo头骨;3)对南京1号头骨的适应性特征-鼻梁高耸进行了论证.这些研究的结果表明:1)南京2号头骨应属于早期智人而不是直立人.南京1号头骨的颅容量,经计算,为871 ml.该颅容量与周口店3号头骨的相当,二者年代也应相近(周口店3号头骨的年代为57.8万年);2)南京1号头骨显示出地区性的形态特征.提示了中国人群南北两大类型的形态差别早在南京直立人生活时期已显出端倪.南京1号头骨及和县头骨可能代表一类中国南方的直立人群,其形态与以周口店直立人为代表的中国北方直立人群有些不同.南京1号头骨在脑颅上显示出较多的与KNM-ER 3733头骨相近的特征,但在面颅上二者相差较大,提示了直立人某些成员在至少1Ma期间脑颅形态保持稳定.南京1号头骨与Bodo头骨的比较结果与"中心和边缘"假说的推测相符合,在东亚这个"边缘地区",现代人群的面颅测量性特征可追溯到直立人群那里;3)南京直立人的高耸鼻梁是适应性特征,是对寒冷或(和)干燥气候适应的结果,并不意味着"西方血统".     

周口店直立人3号头骨的性别和年龄:南京直立人头骨的启示

周口店直立人3号头骨是1929年发现的, 被步达生鉴定为一青春期或成年期的女性个体的头骨。后来, 步达生改变了观点, 认为该头骨是代表青春期早期的男性个体。魏敦瑞同意步达生的意见, 但认为该头骨应属于8岁或9岁的男性个体。此后,周口店直立人3号头骨的性别和年龄的鉴定一直困扰着许多古人类学家。1993年发现的南京直立人成年女性头骨在形态上和尺寸上与周口店直立人3号头骨有相近之处。本文对周口店直立人3号头骨与南京直立人等头骨作了形态和测量上的比较, 结果表明: 从头骨的尺寸大小, 眶上圆枕、枕圆枕和肌嵴的发育程度以及头骨骨壁厚度等来看, 周口店3号头骨有理由被认为是女性个体的。该头骨的鼓骨裂、下颌骨关节窝、泪腺窝、额窦、骨缝等都无法证明其是幼年个体。周口店直立人3号头骨应代表成年女性个体。     

低氧胁迫和恢复对杂交黄颡鱼“黄优1号”肠道组织的影响

为探究低氧胁迫和恢复对杂交黄颡鱼(Pelteobagrus fulvidraco) “黄优1号”肠道组织的影响, 研究运用酶活测定、HE染色、qRT-PCR、TUNEL检测及16S rRNA测序技术等方法, 分析低氧胁迫[(1.0±0.1) mg/L]和恢复下[(7.0±0.5) mg/L]该鱼肠道氧化应激指标、组织结构形态、细胞凋亡及微生物组成变化。结果显示: (1)在低氧胁迫下肠道中抗氧化酶活性(SOD、CAT、GSH-Px)、能量代谢酶活性(LDH)、丙二醛(MDA)和脂质过氧化物(LPO)含量显著升高, 恢复溶氧后氧化应激反应也比较剧烈。(2)低氧胁迫阶段, 肠道组织受损现象逐渐加剧, 杯状细胞肿胀、黏膜层被侵蚀, 恢复溶氧24h后, 缺氧引起的生理变化并未得到明显改善。(3)肠道组织细胞凋亡程度随着低氧时间的延长而加剧, 凋亡相关基因(bax、caspase9和p53)的表达量显著升高, bcl-2基因的表达量则减少。(4)低氧胁迫阶段肠道微生物相对丰度降低, 低氧胁迫72h的处理组中以厚壁菌门(Firmicutes)(47.8%)和拟杆菌门(Bacteroidetes)(40.6%)的丰度最为优势, 恢复溶氧后肠道菌群数量有所增加; KEGG功能预测显示, 多数肠道微生物与代谢通路相关。研究结果可为解析低氧和恢复下杂交黄颡鱼“黄优1号”肠道组织内环境稳态调控机制提供理论依据。     

不同种类无机盐对灰毡毛忍冬“渝蕾1号”悬浮培养体系中细胞生长和绿原酸含量的影响

为提高灰毡毛忍冬"渝蕾1号"悬浮培养体系中绿原酸的含量,该研究探讨了B_5培养基中不同浓度的无机盐对灰毡毛忍冬"渝蕾1号"悬浮培养细胞生物量及绿原酸含量的影响,通过在悬浮培养体系中添加不同浓度的无机盐,采用重量法测定灰毡毛忍冬"渝蕾1号"悬浮培养细胞的生物量及采用高效液相色谱法测定绿原酸的含量。结果表明:当硝态氮和铵态氮配比与B_5培养基中硝态氮和铵态氮配比一致时,即NO_3~-/NH_4~+摩尔比值为13∶1时,培养体系有利于细胞的生长和绿原酸的积累。当KNO_3浓度为3.5 g·L~(-1)时,细胞生物量达到最大,为19.26 g·L~(-1);当KNO_3在较低浓度(0.5 g·L~(-1)和1.5 g·L~(-1))时,积累较多的绿原酸。NO_3~-的两项研究结果均与对照浓度(2.5g·L~(-1))有一定的差异。另外,对(NH_4)_2SO_4来说,在高于对照浓度0.134 g·L~(-1),即浓度为0.268 g·L~(-1)时,生物量和绿原酸含量都达到了最大。P、Ca、Mg三种矿质元素的研究结果表明,当Na H_2PO_4·2H_2O浓度为0.10 g·L~(-1)、Ca Cl_2的浓度为0.20 g·L~(-1)时,细胞的生长和绿原酸的积累均可达到最大值;而对Mg~(2+)来说,低浓度促进细胞的生长,高浓度促进绿原酸的积累。兼顾细胞生物量和绿原酸含量两个指标,需选择适中的浓度。这些结果均与对照浓度有一定的差异。这说明灰毡毛忍冬"渝蕾1号"悬浮细胞所需无机盐的浓度与B_5培养基无机盐的浓度有一定的差异,选择适宜的浓度可促进其悬浮细胞的生长及次生代谢产物绿原酸的积累。该研究结果为绿原酸的工业化生产打下了基础。     

Patterns of Genetic Population Differentiation in Four Species of Amazonian Frogs: A Test of the Riverine Barrier Hypothesis1

Patterns and levels of allozyme variation among populations of Amazonian frogs were used to test the riverine barrier hypothesis of species differentiation. Two frog species were sampled from each of the two main forest habitats on both banks of the Juruá River in the southwestern Brazilian Amazon Basin at various points along its course to contrast different barrier strengths. Scarthyla ostinodactyla and Scinax rubra were sampled from flooded forest (varzea), and Physalaemus petersi and Epipedobates femoralis from non-flooded forest (terra firme). All species showed high levels of within-population genetic variation. Average Nei's (1978) and Rogers’ (1972) genetic distances between sampled sites for all species were high indicating substantial among-population differentiation. The observation of low gene flow between sampled sites within species was further substantiated with Slatkin's (1993) M? analyses. Randomization tests suggested that there was some population structure at a few assayed polymorphic loci that was consistent with the riverine barrier hypothesis. However, it was apparent from the raw allozyme frequency data that these results were largely driven by substantial differentiation at one or a few collecting localities rather than by basin-wide patterns of riverine differentiation. Phenograms using genetic distance matrices supported this interpretation. Patterns of geographic variation are probably more consistent with the idea of this region being a zone of secondary contact.     

人外周血单核细胞来源的树突状细胞的体外“2＋2”快速法培养及其鉴定

以人浓缩白细胞来源的CD14 单核细胞为前体,建立体外快速培养树突状细胞(dendritic cell,DC)的方法.采用密度梯度离心和MACS磁珠分选系统,收集高纯度的CD14 单核细胞;以rGM-CSF、rIL-4联合分化2天诱导不成熟DC,再将分化后的细胞以rTNF-α、IL-1β、IL-6、PGE2共同活化2天得到成熟DC.流式细胞仪检测结果表明,分化2天的不成熟DC具有吞噬能力,且表型HLA-DR、CD40、CD80表达在80%以上,CD83、CD86基本小表达,成熟后的DC能够激活T细胞增殖,HLA-DR表达增高,CD83、CD86表达占85%.     

Skull size and shape variation versus molecular phylogeny: a case study of alpine newts (<Emphasis Type="Italic">Mesotriton alpestris</Emphasis>, Salamandridae) from the Balkan Peninsula

We explored the phylogenetic signal of skull size and shape in alpine newts from the Balkans, a group of European newts that, in spite of their considerable phylogeographic substructuring (as inferred from previous DNA analyses), maintain a conserved phenotype. In terms of skull shape disparity, geometric morphometrics show that the dorsal cranium carries a significant phylogenetic signal, the most notable evidence in this present study. On the contrary, no phylogenetic signal in the shape of the ventral cranium was found. This result indicates that the variation in the shape of the ventral cranium is more prone to other factors and processes, such as adaptations to local environments rather than phylogenetic constraints. Variation in skull size within alpine newts seems to be independent from phylogenetic constraints.     

Isolation and Sequence of Partial cDNA Clones of Human L1: Homology of Human and Rodent L1 in the Cytoplasmic Region

We have isolated cDNA clones coding for the human homologue of the neuronal cell adhesion molecule L1. The nucleotide sequence of the cDNA clones and the deduced primary amino acid sequence of the carboxy terminal portion of the human L1 are homologous to the corresponding sequences of mouse L1 and rat NILE glycoprotein, with an especially high sequences identity in the cytoplasmic regions of the proteins. There is also protein sequence homology with the cytoplasmic region of the Drosophila cell adhesion molecule, neuroglian. The conservation of the cytoplasmic domain argues for an important functional role for this portion of the molecule.     

广东湛江鲤鱼墩遗址人骨的C、N稳定同位素分析:华南新石器时代先民生活方式初探

相对于长江流域和黄河流域而言,华南地区先民生活方式的了解一直较为缺乏。广东湛江鲤鱼墩遗址人骨的C和N稳定同位素分析,显示此遗址的先民主要以海生类资源为食,陆生资源(包括可能的块茎类原始农业和动物)只占次要地位。通过与约同时代黄河流域、长江流域先民的稳定同位素数据比较,可以看出,早在6000年前,我国先民的生活方式就已出现3大类型。     

Myelin Gangliosides of Human Peripheral Nervous System: An Enrichment of GM1 in the Motor Nerve Myelin Isolated from Cauda Equina

Myelins of the PNS were isolated from human motor and sensory nerves of cauda equina, and their ganglioside compositions were compared. The predominant ganglioside in the human PNS myelins, both from motor and sensory nerves, was LM1 (sialosylneolactotetraosylceramide). Sialosyl-nLc6Cer and disialosyl-nLc4Cer, GD3, GM3, and GD1b were detected as common components of the two nerve myelins. Furthermore, it was revealed that the motor nerve myelin contained GM1 (about 15% of total gangliosides), whereas sensory nerve myelin contained only a trace amount of GM1 (less than 5%), by TLC analyses together with TLC immunostaining using anti-GM1 antibody. As for the disialoganglioside fraction, the content of GD1a, as well as that of GM1, differed in motor and sensory nerves. Thus, the different contents of the ganglioseries gangliosides in human motor and sensory nerve myelins were demonstrated.     

A Micromethod for the Isolation of Large and Small Microvessels from Frozen Autopsied Human Brain

Microvessels were isolated from autopsied human brain using a simple procedure involving disruption, sieving, and centrifugation on a sucrose density gradient. The present procedure is characterized by isolation, from frozen autopsied brain, of materials either from the cerebral cortex or white matter, and subsequent separation of the capillary fraction from the large vessel fraction. The preparation appears highly purified under phase-contrast microscopic examination. The purity was also established by the enrichment of gamma-glutamyl transpeptidase activity and by the nearly negligible cerebroside content in the vessel fractions as compared to the brain homogenate.     

Underlying the Mechanism of Vancomycin and Human Serum Albumin Interaction: A Biophysical Study

In the present study, the binding mechanism of vancomycin with human serum albumin (HSA) was determined. Upon addition of vancomycin to HSA, the fluorescence emission was quenched and the binding constant of vancomycin with HSA was found to be 6.05 × 10³ M^?1 at 295 K, which corresponds to –2.16 × 10⁴ J·mol^?1 of free energy. The conformation of HSA was altered upon binding of vancomycin with a decrease in α helix and an increase in β sheets and random coils, suggesting partial unfolding of the secondary structure. Molecular docking experiments found that vancomycin binds strongly with HSA at the hydrophobic pocket through hydrogen bonding and van der Waals interactions. An average binding distance of 4.71 nm has been determined on the basis of the Förster resonance energy theory. It was demonstrated that vancomycin binding to HSA causes protein structural changes. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:463‐470, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21511     

Succession of Exotic and Native Species Assemblages within Restored Floodplain Forests: A Test of the Parallel Dynamics Hypothesis

Exotic plants pose a threat to restoration success in post‐agricultural bottomlands, but little information exists on their dynamics during succession of actively restored sites. We hypothesized that exotic assemblages would establish during succession and that their compositional trends during succession time would mirror those published for native species in other systems, with an early peak in herbaceous richness followed by a decline as woody species establish. In the summer of 2008, we sampled 16 sites across an 18‐year chronosequence of restored forests, with an additional four mature forest stands for comparison, within the Cypress Creek NWR, Illinois, U.S.A. We identified all vascular plant species and quantified canopy openness at three canopy strata, and soil texture and chemistry. Trends in exotic assemblages were significantly correlated with canopy openness at all strata. Richness of exotic and native herbaceous species was related to stand age and consistent with a Weibull regression model. Native and exotic herbaceous cover followed an exponential decay model. Woody native richness over time conformed to a logistic model; woody exotics exhibited no relationship with stand age and were present in sites of all ages. Our results indicate that although their rates of decline differ, herbaceous exotics and natives exhibit similar successional dynamics; therefore, herbaceous exotics may not pose a lasting threat to restoration success in reforested floodplains. Woody exotics can establish across a range of successional stages and persist under closed canopy conditions. Bottomland restorations are vulnerable to the invasion and expansion of exotic plant species even after canopy closure.