Rediscovery of Gastrostyla setifera (Engelmann, 1862) Kent, 1882: morphology and divisional morphogenesis (Ciliophora,Hypotrichida)

The morphology and morphogenesis of the poorly known hypotrichous ciliate Gastrostyla setifera, isolated from a freshwater pond near Harbin, China, are described from both living and protargol silver-impregnated specimens. The Harbin population of this species is characterized thus: medium-sized freshwater Gastrostyla, 150-205 × 70-95 μm in vivo, ellipsoid in shape but somewhat narrowed posteriorly. Contractile vacuole located in left half of mid-body region. On average 48-56 (mean 52) adoral membranelles; 10 frontal and 9-11 ventral cirri; 23-26 left and 30-34 right marginal cirri; usually with four complete dorsal kineties and two dorsomarginal kineties; three caudal cirri present at posterior margin; invariably two macronuclear nodules and two micronuclei. Its morphogenesis reveals the following characteristics: (1) adoral zone of membranelles (AZM) in the opisthe arises from the new oral primordium while the proter inherits the entire parental structure; (2) 10 frontal, 9-11 ventral and five transverse cirri are derived from five frontoventral transverse cirral anlagen together with the undulating membrane anlage; (3) left and right marginal cirri are derived from new anlagen which originate within the old marginal rows; (4) the generation of the dorsal kineties is of the 'two-group-mode'; three left primary dorsal anlagen and two dorsomarginal anlagen appear as two groups in both dividers from which all dorsal kineties are derived (the fourth kinety is formed due to the fragmentation of the third anlage); (5) one caudal cirrus is formed at the ends of each of the first, second and fourth dorsal anlagen.     

Effect of the calmodulin inhibitor R24571 (calmidazolium) on rat embryos cultured in vitro

Summary The possible effects of inhibition of the calcium-binding protein, calmodulin, on mammalian morphogenesis have been investigated by culturing rat embryos in vitro from 9 1/2 to 11 1/2 days of development in the presence of R24571 (calmidazolium), a specific inhibitor of calmoldulin. Embryos cultured in 10^–2 mM R24571 for 48 h show inhibited development and exhibit a range of morphogenetic abnormalities including assymetry and neural tube defects. Embryos exposed to R24571 for the first 24 h of a 48 h culture are more severely affected than embryos exposed to R24571 for the last 24 h.Acknowledgments. We wish to thank Mr C. Veltkamp and Mr B. lewis for their expert help with the scanning electron microscopy and photography.     

扬子鳄附肢的形态发生

本文在３１例扬子鳄胚胎中观察了附肢的形态发生过程，并与密河鳄附肢的形态发生过程进行和讨论，孵化每天 ，前、后肢芽形成处的组织略隆起；第８天时，前、后肢芽突出呈乳状。前、后肢芽分别在１６、２０天出现近轴部与远轴部结构的区分。前肢掌面和后肢 反在第１６－２４天中形成，第２４－３２天中指间裂逐渐形成。     

Molecular basis of morphogenesis during vertebrate gastrulation

Gastrulation is a crucial step in early embryogenesis. During gastrulation, a set of morphogenetic processes takes place leading to the establishment of the basic body plan and formation of primary germ layers. A rich body of knowledge about these morphogenetic processes has been accumulated over decades. The understanding of the molecular mechanism that controls the complex cell movement and inductive processes during gastrulation remains a challenge. Substantial progress has been made recently to identify and characterize pathways and molecules implicated in the modulation of morphogenesis during vertebrate gastrulation. Here, we summarize recent findings in the analysis of signaling pathways implicated in gastrulation movements, with the aim to generalize the basic molecular principles of vertebrate morphogenesis.     

高盒形藻的有性生殖发生

从厦门沿岸分离高盒形藻，培养观察其有性生殖发生．该藻在光诱导下每天发生一次性分化，每次持续４ｈ．从海区采样观察和实验室培养，性分化在６２μｍ以下宽度的细胞中发生．每个精原孢囊产生１２８个单鞭毛精子，精子生活１９ｈ之后存活率大大下降，每个卵囊形成成对的卵子，精子和卵子几乎同步发生．结果表明，该藻可能存在小型和中型细胞分段发生性化和两次细胞复大现象．生殖中呈现的相似和相异特征，显示种间的亲缘关系．     

蛇床愈伤组织的形态发生及植株再生

蛇床幼茎外植体在ＭＳ＋２，４－Ｄ２ｍｇ／ｌ＋ＫＴ０．２ｍｇ／ｌ培养基上形成淡黄绿色松软状愈伤组织。愈伤组织在转入培养基ＭＳ＋ＮＡＡ０．２ｍｇ／ｌ＋２Ｔ０．８ｎｇ／ｌ以后分化出不定芽，在１／２ＭＳ＋ＩＡＡ２ｍｇ／ｌ培养基中可产生不定根，进而发育成为完整植株。愈伤组织在ＭＳ＋２，４－Ｄ０．２ｍｇ／ｌ＋ＺＴＺＴ０．４ｍｇ／ｌ培养基中继代３～４次以后，再转入ＭＳ＋ＮＡＡ０．２ｍｇ／ｌ＋ＺＴ０．８ｍｌ／ｌ培养基中继代１～２次，形成了大量胚状体。胚状体经过球形胚、心形胚、鱼雷胚和子叶胚最终发育成再生植株。器官发生和体细胞胚胎发生这两种形态发生方式在发生顺序、形态特征和所需激素条件等方面都是不同的。     

光质对珙桐幼苗形态建成及光合特性的影响

为探究不同光质对珙桐幼苗的形态和生理指标的影响,采用发光二极管(LED)对珙桐幼苗进行不同颜色的可见光处理(白色,蓝色,绿色和红色).结果表明,红光处理下的珙桐幼苗株高最低但光合色素含量最高;绿光使幼苗叶宽及叶面积明显减小,光合色素含量显著增加;蓝光处理则使幼苗生长较高,叶绿素荧光特性参数及H_2O_2等含量也最高,但光合色素含量和PSⅡ量子产量最低;白光使珙桐幼苗生长最高,但光合色素和H_2O_2及MDA等含量较低.以上结果说明珙桐幼苗在不同的生长环境下能形成不同的生长机制,通过感知光质来调整自身的生理机能,最大限度地进行适应性生长.