头索动物

Here we show that a TH derivative, triiodothyroacetic acid, induces metamorphosis in the cephalochordate amphioxus.

科学家通过研究发现，甲状腺激素的衍生物，一种叫做TRIAC的物质，在头索动物文昌鱼中诱导了变态。

Amphioxus, a cephalochordate, is believed to be the closest living relative of the vertebrate. It is often regarded as an important model animal for phylogenetic studies on the evolution of animals from invertebrate to vertebrate.

文昌鱼是头索动物，被认为是现存的与脊椎动物最接近的无脊椎动物，经常被看作是分析从无脊椎动物到脊椎动物进化过程的一种重要的模式动物。

In fact, this discovery filled the gaps of evolution from cephalopod to the vertebrate.

头索动物与脊椎动物之间的演化空白由此得以填补。

Any of various small, flattened marine organisms of the subphylum Cephalochordata, structurally similar to the vertebrates but having a ''.'notochord'.

蛞蝓鱼类任一种体形较小的头索动物纲的扁平海洋动物，它们在结构上与脊椎动物类似，但只有一个''。

Firstly,the presence and location of AAT in amphioxus was studied by Westernblotting and immunohistochemical methods.The results first revealed that AATpresent in amphioxus,a cephalochordate.Also it was demonstrated that AATdistributed in cellular plasma in hepatic diverticulum,the pouch that protrudesforward as an outpocketing of the digestive tube and extends along the right side ofthe posterior part of the pharynx,which has long been considered to be the precursorof vertebrate liver.In vertebrate,AAT is primary synthesized in liver.

我们首先利用免疫组化和Western blotting方法，研究了AAT在文昌鱼的组织表达和定位，首次在头索动物文昌鱼中证明了AAT的存在，结果显示，AAT定位于文昌鱼肝盲囊的细胞浆内，从AAT在文昌鱼中的合成部位来看，在功能上文昌鱼的肝盲囊等同于脊椎动物肝脏，肝盲囊是在发育分化过程中消化道组织向右前方突出沿着咽后部向前扩展和延伸形成的一个囊袋状结构。

In this study, the genomic structure and regulatory elements of ApoD from 10 representive species including protozoan, invertebrate, protochordate and vertebrate were analyzed and compared. The genomic structure of ApoD is less conserved in organisms from protostome to deuterostome invertebrates, while it is highly conserved among chordates including amphioxus and verebrates. All four conserved cysteine residues are present in amino acid sequence of deuterostome ApoDs, while there are only two cysteine residues in amino acid sequence of protostomes ApoD. Structure divergence between protostome and deuterostome ApoD proteins suggests their function difference. The majority of regulatory elements are present in nearly all organism ApoD genes ranging from unicellular protozoan to mammals, suggesting that ApoD plays a very fundamental role, and possesses a conserved regulatory mechanism. However, there also exist some specific regulatory elements, which are present only in certain species and may perform some special roles.ApoD mRNA expression in murine NIH/3T3 fibroblasts exposed to various stresses such as as hydrogen peroxide and UV light shows dose-dependent increase. And a fly homolog of ApoD, Glial Lazarillo, whose overexpression results in increased resistance to hyperoxia as well as a extension of lifespan under normoxia and resistance to starvation without altering lipid or protein content.

本文首先从生物信息学角度对分属于原生动物、无脊椎动物、头索动物和脊椎动物类群的10种动物ApoD的基因结构及调控区的调控元件进行分析及比较，发现：(1)ApoD基因外显子-内含子结构从原生动物草履虫到原口动物再到后口动物海胆的进化过程中不保守，但在分析的几种脊椎动物中相当保守；(2)文昌鱼ApoD基因扮演从无脊椎动物到脊椎动物承上启下的角色，可能代表了脊椎动物ApoD基因原型；(3)四个半胱氨酸保守位点在后口动物中都存在，而在原口动物中只存在两个，原口、后口动物ApoD蛋白一级结构上的差异反映蛋白功能上可能也存在一定差别；(4)调控区大多数主要调控元件为不同动物共有，说明ApoD主要功能及其表达调控在进化中相当保守；(5)ApoD基因个别调控元件是随着物种进化而出现并开始发挥相关作用，如SF-1；还有一些调控元件在进化过程中还没有发现其规律，这说明ApoD某些功能和基因表达调控模式可能因物种不同而存在一定的差异。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。