THE STRUCTURE OF FISH GILLS IN RELATION TO THEIR RESPIRATORY FUNCTION

1. The general structure of the gills of different fishes is compared and it is concluded that, though essentially the same, there are certain differences by which they can be recognized. Possible ways in which they may have evolved from one another are considered. 2. A detailed account is given of the structure of the secondary lamellae, where gaseous exchange takes place, and it is shown that two epithelial sheets are separated by a vascular axis mainly composed of pillar cells overlain by a basement membrane on each side. Blood pathways through the gills are discussed in relation to their respiratory function. 3. The embryonic development of gills is described and evidence regarding homo-logies of different structures, particularly the pillar cells, is reviewed. 4. The gills of fish having different modes of life show variations in (a) the number of arches, (b) the number and length of the gill filaments, and (c) the size and frequency of the secondary lamellae. Ways in which measurements of gill area may be carried out and some of the complications involved are reviewed and a summary given of measurements made for a wide variety of species. Measurements of the thickness of the water-blood barrier are also discussed; the more active fish generally have thinner water-blood barriers and larger gill areas. 5. The different mechanisms of gill ventilation are summarized and characteristics of gill resistance in elasmobranchs and teleosts are compared. Gas exchange is discussed in relation to available techniques and the current terminology and symbols, and to indicate the value of analogies between gill exchangers and systems studied by engineers. 6. It is outlined how studies of the functioning of gills during coughing, parasitic infection, and in polluted waters add to knowledge of their role in respiration.     

STRUCTURE AND FUNCTION OF THE STROPHIOLAR PLUG IN SEEDS OF ALBIZIA LOPHANTHA

Entry of water into the testa of hard seeds of Albizia lophantha (Willd.) Benth. is controlled by a small strophiolar plug (0.3 × 0.25 mm), adjacent to the hilum, which is lost by eruption after heating. Movement of water through the testa is facilitated by the vascular bundle which arches close to the strophiole. Each seed imbibes 90 to 110 μl of water. This water enters the testa with an average flux of 165 μl/mm²/hr. Development of the testa is described with particular relevance to the strophiolar plug and associated tissues.     

飞蝗复眼生理和结构上的节律变化

采用细胞内记录和光镜方法研究了飞蝗(Locusta migratoria)夜间和日间在暗适应和明适应状态下小网膜细胞角敏感度以及晶锥和小网膜细胞之间区域结构上的变化.结果表明小网膜细胞角敏感度的变化不仅仅由于晶锥周围主色素细胞色素颗粒的移动,而且也由于小眼感杆束结构上的节律变化.     

昆虫脑中央复合体的结构与功能研究进展

中央复合体是昆虫脑内具有显著特征的一个重要结构,它位于昆虫脑的中央,主要包括四个亚结构,相互间形成高度组织化的网络连接。中央复合体通过大范围神经元与多种感觉神经元和运动神经元相连,是一个控制脑的高级功能的中心。近年来的研究表明中央复合体参与了记忆的形成、运动的协调与控制以及处理偏振光进行导航等多种功能。揭示中央复合体参与以及调控这些复杂功能的神经机制,必将会极大地促进我们在神经回路层次上理解脑的高级复杂功能。     

生态系统中Lyapunov函数的构造

本文讨论生态模型中Liapunov函数的构造方法．典型的Liapunov函数的构造步骤和某些应用被综述．     

皱纹盘鲍肠粘膜上皮的结构和功能

以透射电镜和扫描电镜观察、组织化学及酶活性测定等方法研究了皱纹盘鲍的肠和直肠,肠和直肠粘膜上皮由5种细胞组成。具微绒的柱状细胞呈现吸收细胞的超微结构特征,纤毛柱状细胞参与运输食物颗粒和粪便,Ⅰ型腺细胞具蛋白酶、非特异性酯酶和脂酶活性,以顶浆分泌形式分泌消化酶,Ⅱ型腺细胞分泌物可能与包裹粪便有关,状细胞分泌酸性粘多糖。体外酶活性分析表明肠和直肠粘膜上皮分别具有4种和3种植物多糖酶。     

哺乳动物细胞去核产物(胞质体及核体)的结构与功能研究

1967年Carter发现细胞松弛素可以诱发组织培养细胞的自发排核之后,Prescott(1972)借助细胞松弛素存在下的离心处理,使这一排核现象普遍化,从而确立了体外细胞去核的标准方法。经过不断改进(croce et al., 1974;Veomett et al., 1976;Lucas etal., 1976;Wigler et al., 1975),现在,这一技术已广泛应用于细胞学研究的各个重要领域(Mc Burney et al., 1979;Goldman et al., 1974;du Bols et al., 1980)。细胞去核技术及其应用的研究在我国已有初步开展(陈瑞铭等,1979;沈鼎武等,1980)。本实验对二种上皮型传代细胞系进行了去核手术,用扫描电镜和透射电镜对所获得的胞质体     

新疆的微藻及其群落结构

为了解新疆的微藻资源及其群落特征,研究于2013年5月和2014年6月对新疆包括荒漠、草甸、农田、滩涂等土壤生境和湖泊、水库、河流、池塘、沟渠等水体生境中的微藻进行了采样调查,共采集到标本329个,其中水样256个,土样73个。经室内鉴定发现,陆生藻有77种,优势种呈蓝藻-绿藻型,主要是席藻属(Phormidium)的种类、具鞘微鞘藻(Microcoleus vaginatus)、土生绿球藻(Chlorococcum humicola);水生藻有272种,优势种呈绿藻-硅藻-蓝藻型,主要集中在颤藻属(Oscillatoria)、席藻属(Phormidium)、栅藻属(Scenedesmus)、单针藻属(Monoraphidium)和舟形藻属(Navicula)。整体而言,北部中温带干旱区的微藻较南部暖温带极端干旱区更丰富,而且主要集中在中温带干旱区的滩涂、湖泊和河流生境。依多维尺度分析发现,土壤生境下同一气候区的滩涂和草甸的微藻群落结构较为相似,荒漠和农田生境的群落结构无气候区域差异。在水生生境下,暖温带极端干旱区河流中的群落结构与其他4种水境中差别较大;中温带干旱区的湖泊和河流相似,其他生境中的差别都较大,这说明气候带和生境类型都对微藻群落有影响。       

水螅的反口孔结构和功能

在２３０个水螅（Ｐｅｌｍａｔｏｈｙｄｒａｐｓｅｕｄｏｌｉｇａｃｔｉｓ）中观察到３８例反口孔排物过程。反口孔静止时,基盘附着层外表中心见不到孔迹。反口孔开启时,有废物或气体从孔内排出。连续切片检查,发现反口孔排物前,基盘腔内堆积有食泡残骸等许多废物,孔周死亡细胞和断裂废弃的中胶层在反口孔开启时脱落。非排物期,基盘附着层中心处缺少中胶层。根据观察结果,对反口孔的结构特点及其生理功能作了讨论。     

革螨跗感器的结构和功能

本文进一步研究了:④厩真厉螨截肢前后的爬行行为,表明第1对足其感觉功能;②用古拉广厉螨分别截各对足驱避反应的对比试验,见到只有当截去第1对足跗节时失去嗅觉功能,而截去第Ⅱ、Ⅲ、Ⅳ对足时,各组都仍有嗅觉功能;⑤对格氏血厉螨、厩真厉螨、毒厉螨和鼠颚毛厉螨进行涂漆前后的驱避试验,显示当跗感器被涂满封闭,则嗅觉功能消失;④以0.5%结晶紫或龙胆紫液染色的截肢标本,观察了厩真厉螨、毒厉螨、格氏血厉螨、古拉广厉螨及尾足螨股一种螨,足Ⅰ跗节末端凹窝中,至少都存在两类感毛,钝钉型感毛和长而尖的刚毛型感毛;⑤厩真厉螨雌螨和幼螨跗感器的钝钉毛分别为8根和5根,另外各有2根短而尖的毛,分别测定了长度,描述了形态特点;⑥透射电镜观察厩真厉螨、毒厉螨等的跗感器钝钉毛,毛外围有表皮壁,壁上有很多微孔,内有中心腔,腔内有树突。属化感器——嗅觉器;⑦电生理技术研究,当用氨和醋酸的气体刺激厩真厉螨、毒厉螨的离体足Ⅰ时,均产生明显的应激电位差,充分证明足Ⅰ辩节有嗅觉功能。     

白沙蒿种子萌发特性的研究 I. 粘液瘦果的结构和功能

白沙蒿(Artemisia sphaerocephala Krasch.)是中国西北部沙漠的流动及固定沙丘上广泛分布的优势种灌木。瘦果小而轻,借助显微镜和扫描电镜对瘦果的形态结构进行了观察,其种子的种皮与果皮愈合,果皮外层为很厚的粘液层,其粘液层在遇湿后迅速吸水膨胀,其重量增至原来的589倍。在自然生境中,粘液物质将沙粒粘附于瘦果的周围,使瘦果的重量发生变化。瘦果能长时间在水上漂浮,粘液物质有助于种子的萌发和苗的发育。白沙蒿产生三种不同颜色的瘦果,其种子具有不同的萌发速率但最终达到相同的萌发率。研究表明瘦果的粘液物质对白沙蒿种子的传播与萌发具有重要的生态意义。     

THE FINE STRUCTURE AND FUNCTION OF THE CONTRACTILE AXOSTYLES OF CERTAIN FLAGELLATES

The axostyles of the flagellates Oxymonas, Saccinobaculus, and Notila are large ribbon-shaped structures which undulate actively in the cytoplasm. The form of their movements is described and illustrated. Axostyles consist of regular arrays of longitudinal fibres, the number of which varies between 100 and 5000 in different species. The fibres are about 240 A in diameter, apparently hollow, regularly cross-banded with a periodicity of about 150 A, and connected by delicate cross-links, also at regular intervals of about 150 A. They resemble very closely the central fibres of cilia and flagella. No other structural components are present, except at the anterior end, where the fibres are attached to one or more basal bodies, and at the posterior tip, where they are anchored to the plasma membrane. The relevance of the findings to an understanding of the mechanism of ciliary and flagellar movements is discussed.