鱼类的干扰素系统和干扰素系统基因的鉴定

干扰素(Interferon,IFN)是最早发现的一种细胞因子.虽然有些组织和细胞能检测到IFN的组成型表达,但在正常情况下,生物机体一般只在受到病毒和细菌感染,或用Poly I:C、促细胞分裂素等诱导剂人工诱导时分泌IFN.IFN系统是脊椎动物抵抗病毒入侵的第一道屏障,能在病毒感染后几小时内就迅速起作用,而特异性免疫抗体必须在几天或几周之后才由淋巴细胞产生.       

THE CHITIN SYSTEM

• 1 The view is supported that chitin is not found in Deuterostomia because of the absence of chitin synthetase, and is not found in higher plants because of the absence of glucosamine. In Fungi, control mechanisms are present affecting the synthesis of glucosamine; chitin is often present, but when it is absent this probably results from a failure to synthesize glucosamine.
• 2 A review of conformation maps for cellulose and chitin indicates the possibility of a slightly right-handed twist in small groups of chitin chains.
• 3 The occurrence of α, β and γ-forms of chitin in the peritrophic membranes of various insects is described. Gamma chitin seems to be the commonest form.
• 4 In several beetles, optical and electron-microscope studies trace the formation of chitinous cocoon fibres from larval peritrophic membrane and define the discrete ribbon-like nature of the, β chitin produced in the mid-gut.
• 5 By studying apodemes it is found that orthopteroid insects are most varied, different molecular structures being present in levator, depressor and pretarsal tendons. By contrast, Hymenoptera and Coleoptera show very similar structures in all three apodemes as well as in other parts of the cuticle. Apodemes are regarded as sampling the cuticle at their varying points of origin; they provide especially favour able material for diffraction studies.
• 6 In arthropod cuticles there is evidence for the widespread occurrence of α chitin micelles which are three chains thick in the direction of the c axis. This is compared with the structure of γ chitin where the chains repeat in groups of three along the c axis.
• 7 Changes in the diffraction pattern are related to the series of proteins defined by Hackman. The chitin-protein complex is not affected by water or neutral salt extrac tion, but is disrupted by treatment in urea.
• 8 Electron microscopy defines the unit of structure as a composite microfibril: a core of chitin surrounded by adsorbed proteins. This consists of ‘primary’ protein (often repeating as regular units along the fibrils) and a quantity of ‘satellite’ protein which obscures the imaging of the regularly arranged ‘primary’ protein. There are apparent ‘bridges' between the microfibrils.
• 9 New diffraction data give information about the size and arrangement of micro-fibrils. These fibrils may be arranged in layers of ‘rods’, or as an hexagonal arrange ment of ‘rods’.

     

家庭遥控影像系统

计算机网络的应用可以提供设计一个家庭影像系统,该系统的主要目标是提供现场呼叫医生在家里及时查看影像资料。     

二种群生态系统的能量结构分析

每一个生命系统均存在一个能量系统与之相对应。能量进入生命系统后按生理的组织和功能进行分配,形成具有特定的能量传递关系,组分配置关系及相互关联形式的能量结构,这种结构是完成一定生命功能的物质基础,也是不同生命系统之间相互区别的重要特征。以二种群生态系统分析为例,从其能量的传输类型,配置和奇点的控制特性三个方面扼要地介绍了生命能量系统结构的概念和分析方法。     

应用系统理论的方法建立套作玉米系统的数学模型

一、前言 目前,系统理论越来越广泛地深入地应用到各个科学研究和生产领域,甚至社会科学的范围。通常我们最简单地用一个方框图表示一个系统(图1)。     

THE EARLY SOLAR SYSTEM

Life arose on an early Earth which was the product of the conditions present, and processes operating, during formation of the solar system. The formation and early state of the solar system are reviewed in order to better understand the nature of the early Earth, and to constrain the conditions present during the origin and early evolution of life on this planet.     

THE PORPHYROPSIN VISUAL SYSTEM

1. In the rods of fresh-water and some anadromous fishes, rhodopsin is replaced by the purple photolabile pigment porphyropsin. This participates in a retinal cycle identical in form with that of rhodopsin, but in which new carotenoids replace retinene and vitamin A. 2. Porphyropsin possesses a broad absorption maximum at 522 ± 2 mµ, and perhaps a minimum at about 430 mµ. The vitamin A-analogue, vitamin A₂, possesses a maximum in chloroform at 355 mµ and yields with antimony trichloride a deep blue color due to a band at 696 mµ. The retinene-analogue, retinene₂, absorbs maximally in chloroform at 405 mµ and possesses an antimony chloride maximum at 706 mµ. 3. Its non-diffusibility through a semi-permeable membrane, salting-out properties, and sensitivity to chemical denaturants and to heat, characterize porphyropsin as a conjugated carotenoid-protein. 4. The porphyropsin cycle may be formulated: porphyropsin See PDF for Structure. retinene₂-protein ₍₂₎ ^→ vitamin A₂-protein ₍₃₎ ^→ porphyropsin. Isolation of the retina cuts this cycle at (3); denaturation procedures or extraction of porphyropsin into aqueous solution eliminate in addition (1) and (2). 5. The primary difference between the rhodopsin and porphyropsin systems appears to be the possession by the latter of an added ethylenic group in the polyene chain.     

金丝猴(RHINOPITHECUS)的动脉

动脉在体内的分支情况与机体各部分的结构和功能及其发育情况是相适应的,随着物种的分化,动脉的分支情况也产生了差异,并在一定程度上反映出动物在进化过程中所处的地位。所以,研究动脉的分支是推导动物演化趋向的根据之一。 关于灵长类动脉的研究,已涉及绝大多数种类,但在猴科中,尚未做过金丝猴动脉的研究。本文报导了金丝猴的动脉,并与有关种类的动脉分支情况作了比较。     

四爪陆龟消化、呼吸系统的解剖

四爪陆龟（Ｔｅｓｔｕｄｏｈｏｒｓｆｉｅｌｄｉ）的消化管总长度为体长的４．５—４．８倍。喙缘锋利，硬腭侧缘具细齿，舌不伸出口，食道扩展性强，胃呈囊状，被肝叶覆盖，小肠较长，盲肠发达。肝较大，重１８．３ｇ，分左叶、中叶和右叶，绿色胆囊位于右肝两小叶间。胰腺长条形，分布于十二指肠内。肺长囊形，紧贴在背甲的内表面，位于肩带和腰带之间。气管较短由１５－２０个软骨环组成，支气管较长由７０个左右的软骨环组成。