盐度对企鹅珍珠贝足丝分泌的影响

企鹅珍珠贝（Pteria penguin）是生产附壳珍珠的大型海水经济贝类,其依靠强壮的足丝将自身固定在硬质基底上,抵抗水流的冲击和抵御被捕食等。足丝分泌和足丝的形状很容易受到环境的影响,本实验采用盐度30为低盐度组、盐度35为中盐度组和盐度40为高盐度组,研究这3种盐度对企鹅珍珠贝足丝分泌、足丝直径和足丝拉力的影响,通过单因素方差分析法（LSD法）分析这三个足丝相关指标在3种盐度组间是否存在显著性差异。结果显示,3种盐度下企鹅珍珠贝足丝附着率无显著差异,但在整个实验周期72 h内,中盐度组的足丝分泌总数为（48.7 ± 15.1）根,显著高于低盐度组的（24.7 ± 5.0）根和高盐度组的（13.3 ± 1.5）根。在实验的前6 h内,中盐度组的足丝首次附着率显著高于低盐度组和高盐度组（P < 0.05）,但在后续的12 h、18 h、30 h、42 h、54 h和66 h这6个时间点,3个盐度组的足丝首次附着率均无显著性差异。足丝直径未受盐度变化的影响,但盐度对足丝拉力具有显著影响,中盐度组的足丝拉力显著高于低盐度组和高盐度组（P < 0.05）。上述结果表明,企鹅珍珠贝为适应一定范围内盐度的改变,会在短时间内通过抑制足丝分泌来减少能量消耗,随着对环境的适应足丝分泌会恢复。盐度影响足丝分泌且对足丝拉力影响显著,但对足丝直径无明显影响。本研究可以为企鹅珍珠贝养殖及珍珠插核培育提供理论基础。     

企鹅珍珠贝不同地理群体遗传多样性的fAFLP 分析

为阐明企鹅珍珠贝(Pteria penguin)不同地理种群的遗传多样性机制, 采用荧光标记扩增片段长度多态性(fAFLP)技术分析了企鹅珍珠贝广西涠洲岛、广东流沙湾和海南黎安3 个不同地理群体的遗传多样性。选取7 对引物组合对90 个个体(每个群体30 个)进行fAFLP 扩增, 结果发现每个个体均能扩增出清晰的、可重复的扩增条带, 每对引物的扩增位点数在100—163 之间, 共得到895 个扩增位点, 多态位点数为865 个; 涠洲岛、流沙湾和黎安群体的多态位点比例分别为70.73%、63.13%、66.82%。Nei 遗传多样性指数为0.1634、0.1558、0.1783, Shannon 遗传多样性指数为0.2635、0.2474、0.2932。3 个群体间遗传相似度在0.9722—0.9824之间, 遗传距离在0.0177—0.0282 之间。根据遗传距离绘制UPGMA 聚类图, 但Mantel 检验结果显示企鹅珍珠贝三群体间的遗传距离与地理距离之间无显著相关。Shannon 遗传多样性指数和AMOVA 分析, 结果均显示企鹅珍珠贝的遗传变异主要来源于群体内个体间, 7.91%的遗传变异来自群体间, 92.09%的遗传变异来自群体内。分析群体的显性基因型频率分布和基因流Nm 发现3 个群体有基本相同的遗传结构, 有明显的基因交流。研究结果表明北海涠洲岛群体、湛江流沙湾群体和海南黎安群体的企鹅珍珠贝种质有较高的多态位点比例, 但未发生显著地理分化。这一结果为我国企鹅珍珠贝的良种选育以及种质资源保护措施的制定提供了参考依据。     

企鹅珍珠贝微卫星标记与生长性状的相关性研究

研究利用5个高度多态性的微卫星标记, 对500个企鹅珍珠贝(Pteria penguin)的4个生长性状进行了关联分析。结果显示, QEB-D15和CL-232两个微卫星标记与企鹅珍珠贝的壳宽呈极显著相关(P＜0.01); 位点QEB-D15基因型是239/263的个体壳宽为最大值, 基因型是239/273的个体壳宽为最小值, 推测263 bp等位基因与壳宽之间存在正相关关系, 而273 bp等位基因与壳宽之间存在负相关关系; 位点CL-232基因型为157/174的个体壳长、壳宽、总重的均值较同一位点的其他基因型均为最大值, 该基因型推测为优势基因型; 而基因型为177/192的个体壳长、壳宽、壳高和总重的均值较同一位点的其他基因型均为最小值, 推测该基因型为劣势基因型, 上述结果可为企鹅珍珠贝分子标记辅助选择育种提供理论依据和参考。     

送只企鹅过圣诞

叮叮当,叮叮当,铃儿响叮当。一年一度的圣诞节马上就要到啦!在等待圣诞老人带给你惊喜之前,请先接住我特意为你准备的大礼包吧!我保证,这份与众不同的礼物绝对会让你尖叫连连。因为它们来自遥远的南极,不仅会走会跳,还能喊能叫——没错,即将出现在你床头的是一群活生生的企鹅!我特意挑选了其中最好玩、最活跃的三种:巴布亚企鹅、阿德利企鹅和帽带企鹅,希望它们能带给你一个不一样的圣诞节!亲爱的朋友,快张开双臂,欢迎它们成为你家的新成员吧!     

甘南地区小红珠绢蝶生物学特性研究初报

小红珠绢蝶Parnassius nomion Fischer von Waldheim在甘肃甘南1年发生1代。翌年5月上旬幼虫孵化,6月下旬开始化蛹,7月下旬至8月上旬,成虫开始羽化,8月中旬至9月上旬成虫开始产卵,该虫以卵越冬。     

纹颊企鹅

<正>纹颊企鹅(Pygoscelis antarctica),也称帽带企鹅,是世界上18种企鹅之一,最显著的特征是颌下有一条黑色细条纹,类似海军军官的帽带。主要分布于南极半岛、南设德兰群岛等地,在我国南极长城站及其周边地区常见,全球种群数量约150万只。纹颊企鹅为中等体型的企鹅,体重3.5~5.5 kg,     

洪氏环企鹅骨骼的解剖学特点

采用解剖学方法对1只雄性洪氏环企鹅(Spheniscus,humboldti)骨骼系统进行了详细的观察、描述.结果表明:企鹅骨骼结实、沉重不充气;喙长,前端略下弯,颞部呈深凹陷状;肩胛骨及胸骨龙骨突发达;胸椎不愈合;前肢骨骼扁平,特化为鳍状,翼内关节活动性较小,第一掌骨及拇指消失;髌骨发达,跗跖骨短而宽扁.这些特征主要体现了洪氏环企鹅对海中潜水、游泳、取食以及陆地直立的适应.     

企鹅的悲喜剧——笔走南极(七)

“企鹅的肉好吃吗?味道怎样？”自1g89年4月我从南极大陆回到祖国后．记不清有多少人向我提出这个问题。对方询问时往往是一脸的认真。希望我说出企鹅肉的味道如何。然而,我是回答不上来的,恐怕所有中国南极科学考察队员都无以作答。尽管企鹅是极易捕捉的,它的笨拙决定它没有快速奔跑能九尽管企鹅往槎成群地     

褶纹冠蚌光珠与骨珠珍珠囊差异的研究

运用多种组织化学方法和电镜技术研究了褶纹冠蚌光珠和骨珠珍珠囊表皮细胞的形态结构、分泌物性质和功能等方面的差异。结果表明：骨珠珍珠囊表皮细胞合成和分泌珍珠前体物质的能力较光珠的强,故骨珠的形成速度比光珠快;光珠和骨珠珍珠囊表皮细胞合成和分泌的蛋白质的差异决定了光珠和骨珠的形成;光珠和骨珠珍珠囊表皮细胞的形态结构特征差异可作为检验和预测人工培育珍珠质量的细胞学标准。     

Drag Reduction in a Swimming Humboldt Penguin, Spheniscus Humboldti, when the Boundary Layer is Turbulent

An area of protruding feathers found around the beak of many penguin species is thought to induce a turbulent boundary layer whilst swimming. Hydrodynamic tests on a model Humboldt penguin, Spheniscus humboldti, suggest that induced turbulence causes a significant reduction in boundary layer height, flow separation, and an average of 31% reduction in drag ( 1.0 m/s to 4.5 m/s). Visualisation of surface flow showed it to follow the body profile, over the feet and tail, before separating. Movement of the feet in swimming penguins correlates with steering of the bird. Induced turbulence may therefore further increase swimming efficiency by reducing the amount of foot movement required to direct the swimming bird.     

Hidden keys to survival: the type,density, pattern and functional role of emperor penguin body feathers

Antarctic penguins survive some of the harshest conditions on the planet. Emperor penguins breed on the sea ice where temperatures drop below −40°C and forage in −1.8°C waters. Their ability to maintain 38°C body temperature in these conditions is due in large part to their feathered coat. Penguins have been reported to have the highest contour feather density of any bird, and both filoplumes and plumules (downy feathers) are reported absent in penguins. In studies modelling the heat transfer properties and the potential biomimetic applications of penguin plumage design, the insulative properties of penguin plumage have been attributed to the single afterfeather attached to contour feathers. This attribution of the afterfeather as the sole insulation component has been repeated in subsequent studies. Our results demonstrate the presence of both plumules and filoplumes in the penguin body plumage. The downy plumules are four times denser than afterfeathers and play a key, previously overlooked role in penguin survival. Our study also does not support the report that emperor penguins have the highest contour feather density.     

The construction of ethnic categories: Discourses of ethnicity in The Netherlands

This article is concerned with the way ethnic and racial categories are achieved and sustained in daily talk. We argue against the notion of social categories as immanent cognitive structures whose existence and significance can be taken for granted. It is emphasized that categories are constructed in discourse. The construction and representation of ethnic categories are studied by analysing discussions held by some ethnically Dutch inhabitants of an inner‐city quarter in Rotterdam. There were two discussion groups (six and five participants respectively) and each group met one evening a week in a row in the local community centre for four weeks. All eight sessions were taped and transcribed and each session lasted approximately two and a half hours. Our goal is to describe in detail some of the discourses that are being used to achieve and sustain specific categorical representations. First, the nature of the different categorical constructs used is analysed. It is shown that people use different criteria for constructing ‘us‐them’ distinctions and that this multiplicity is rhetorically useful. Second, the ways in which categorical constructions are represented and vary in discourse are identified and outlined. Subsequently, the means by which these representations are achieved and sustained is examined. Attention is focued on comparisons that are being made, on the use of metaphors, and on the process of concretiz‐ation. Third, some of the cultural values drawn upon in legitimizing the representations are explored. It is shown how the taken‐for‐granted notions of freedom, merit, equality and tolerance are used to construct and legitimize ethnic representations. Finally, it is argued that a discourse approach can provide important additional insights into issues concerning ethnic relations and racism. For one thing it can help to develop strategies for reconstructing the predominant distinction between ‘us’ and ‘them’.     

The winter distribution of chinstrap penguins from two breeding sites in the South Shetland Islands of Antarctica

Satellite telemetry was used to determine the winter movements of eight chinstrap penguins from two breeding colonies in the South Shetland Islands, Antarctica during the 2000 and 2004 austral winters. Chinstrap penguins foraged largely inshore, on the shelf, north of the South Shetland Islands during 2000, but foraged mainly offshore in pelagic waters in 2004. Analyses of foraging trip durations during the chick-rearing periods that preceded the 2000 and 2004 winters suggest that prey were more abundant inshore during the summer of 2000 than in 2004. Oceanographic data further revealed the presence of a strong shelf-slope front in 2000 that was absent in 2004. In addition, two of the six chinstrap penguins from the colony in Admiralty Bay migrated from the South Shetland Islands region to the vicinity of the South Orkney and South Sandwich Islands, distances of 800 and 1,300 km, respectively. We postulate that the differences in winter migratory behavior among chinstrap penguins from this colony may reflect individual ties to different ancestral epicenters of chinstrap populations; one older and local in the South Shetland Islands and one relatively recent, arising from the emigration of chinstrap penguins that occurred during the expansion of this species in the mid-1900s.     

异化金属还原菌的研究进展

微生物利用金属氧化物作呼吸作用的最终电子受体是一种新的代谢途径。该过程微生物利用有机底物异化还原金属氧化物进行生长代谢。异化金属还原菌对于研究探索古生物呼吸形式、界定生命的上限温度等生命科学问题具有重要研究价值,同时在生物整治、微生物燃料电池等方面具有广阔的应用前景。对异化金属还原菌进行了综述,并对这类菌的研究应用给了评述和展望。     

Zerfurchte Flügel und zähe Luft

Corrugated wings and viscous air Airborne microorganisms were bound to evolve morphologic characteristics that are optimized with respect to their scale regime. Vortices – stationary or dynamically generated – herein are playing a dominant role. The generation of vortices in microorganisms is assisted by micro-morphologic structures as veins, grooves and pores.