In vitro protein digestion, and growth of Atlantic salmon with different trypsin isozymes

Growth and in vitro digestion was examined in three iso-trypsin phenotypes (patterns 1, 2 and 2) of Atlantic salmon, Salmo salar. Fish grew equally well during the 128 day experiment irrespective of phenotype. At day 64 and 91, weight-specific growth rate of 2 phenotype animals were significantly lower (p < 0.05). At the end of the experiment, significant differences (p < 0.05) were noted between groups with respect to size. An in vitro method was used to examine protein digestion by the different trypsin phenotypes. Three fish meals (FM I > FM II > FM III) of high, medium and low quality, as defined by chemical analyses, were used. Phenotype 1 was able to differentiate between three fish meals ranking FM I > FM II > FM III. In contrast, phenotypes 2 and 2 were not able to separate between meals. In vitro digestion efficiency was dependent upon the three salmon types, ranking phenotype 2 > 1 = 2.     

培养时间和接种密度对咖啡短体线虫繁殖和形态的影响

采用胡萝卜片培养短体线虫技术,测试不同培养时间和接种密度对咖啡短体线虫(Pratylenchus coffeae)繁殖和形态的影响。结果表明,在25℃培养条件下,每片胡萝卜(厚10 mm,直径3 cm)接种25头线虫雌虫,线虫的数量随培养时间的延长而增加,前3周线虫的繁殖系数为6.24,线虫的群体数量增长缓慢;第3~6周线虫的繁殖系数略有增高,为8.99;第6~9周其繁殖系数高达17.88,线虫群体数量快速增长;之后,线虫群体数量增速下降,其繁殖系数降为1.42。在接种不同密度线虫的实验中,线虫的群体数量均显著增长,其繁殖系数在不同接种密度处理中差异不显著;随机挑取10头雄虫与雌虫,比较不同线虫密度对线虫形态特征的影响,结果表明,线虫密度除对雌虫的b值(体长/头顶至食道腺与肠连接处长)有显著影响外,对雄虫和雌虫的其他形态特征测量值均无显著影响。     

马氏珠母贝两个不同地理种群的形态性状

在“珍珠贝育种规划（Pearl Oyster Breeding scheme,POBs）”中,马氏珠母贝的两个地理种群——印度养殖种群和三亚野生种群正在作为两个基础群（Basic population）建立专门化品系,通过杂交获得杂种优势,构建杂交配套系以培育优良品种。从形态上看,印度养殖种群体个体大,而三亚野生种群体个体小;三亚野生种群的壳宽系数为0．18,大于印度养殖种群的0．15,三亚野生种群的贝体外形较凸,而印度养殖种群的贝体外形扁平。三亚野生种群的壳重指数（25．30）大于印度养殖群体（18．80）。通过成像色度检测分析系统分析,每个种群都有自己的颜色特征值——三刺激值和颜色参数;比较两个种群颜色参数Lab时表明,三亚野生种群贝壳珍珠质颜色的明度（L）大于印度养殖种群,色品比印度养殖种群更偏向绿色（-a）和黄色（b）,印度养殖种群色品偏向蓝色和红色。两个种群间贝壳珍珠质的色差（△XEab）为10．69,属于大色差,感觉强烈。     

An integrated Assessment of a group with complex systematics: the Iberomaghrebian lizard genus Podarcis (Squamata,Lacertidae)

A critical review of the evolutionary biology of Iberian and North African lizard members of the genus Podarcis (Lacertidae) based on phylogeny, phylogeography, morphometrics, behavior, ecology and physiology is presented. The Iberomaghrebian region is inhabited by at least 12 different evolutionary lineages that group into a monophyletic clade (except Podarcis muralis). In contrast to the current taxonomy, the saxicolous ‘Podarcis hispanica’ is paraphyletic with respect to Podarcis bocagei and Podarcis carbonelli, two currently recognized species. Nodes in the phylogenetic tree are deep, resulting from old divergences, clearly preceding the Pleistocene. Nevertheless, more recent range changes as a result of glaciations are also evident. The most plausible evolutionary scenario for this group indicates both vicariant and dispersal events. Although parapatry between lineages is the rule, sympatry and even syntopy are frequent, but usually between ground‐dwelling and saxicolous forms. Contacts between forms with similar habitat use are rare and local. Morphological distinctiveness between lineages has been demonstrated, indicating historical constraints. However, other characters have repeatedly evolved under similar environmental pressures independently of the evolutionary lineage. Strong sexual dimorphism derives from sexual selection and is attained before sexual maturity, although developmental restrictions exist. Variation between populations is also important and derives from local variation in both natural (habitat, climate) and sexual (density) selective pressures. Evidence for short‐term changes has already been found, particularly in insular populations. Reproductive isolation between syntopic forms and partner recognition are based on male—male competition and on visual and chemical recognition of females by conspecific males. Despite this ancient diversification, most forms maintain a degree of reproductive compatibility. Hybridisation may occur, but is limited, and there is evidence of selection against hybrids. The ecological analysis presented here does not support exploitative competition, but rather behavioral interference between forms. Ecomorph classification of lineages suggests character displacement between those with extensive range overlap. Finally, a critical assessment of the specific status of all lineages is provided and directions for further research are suggested.     

鸟类飞羽羽轴髓质结构的定量分析

鸟类飞羽羽轴机械性能一部分来自髓质,但是髓质泡沫结构如何影响羽轴机械性能的问题仍未被研究。本文对5种鸟类初级飞羽羽轴的髓质形态结构进行研究,测定了腔室的大小、壁厚度等形态计量学参数,分析了这些结构参数与体重的关系以及腔室在抵抗形变的作用过程。结果显示,髓质腔室断面的平均周长(l,表示腔室的大小)介于74.26±11.27～153.02±59.01μm之间,在一些种类(如丹顶鹤和毛脚鵟),外周髓质的l值显著大于中央髓质(P<0.05),而在另一些种类(鸿雁、银鸥和短耳鸮)择二者差异不显著(P>0.05);腔室壁厚度(t)介于0.51±0.15～2.14±1.11μm之间,在所有种类外周髓质的t值均显著(P<0.05)或极显著(P<0.01)大于中央髓质。l和t之间没有显著的相关性(P>0.05),但是外周髓质的t值与翈面面积、体重均呈显著的线性相关(P<0.05)。上述结果表明,空球形腔室可以把某一点上的压力有效地传递和分配到整个羽轴内部,并在每个形变的腔室壁上积累势能;外周髓质对羽轴机械性能的贡献大于中央髓质,这种贡献主要缘于腔室壁的厚度而不是腔室的大小。但是,腔室大小在不同鸟类显出与扑翼强度相一致的关系。