AcMNPV核衣壳的形态发生

报道了缺失多角体蛋白基因的AcMNPV在sf9细胞内核衣壳的形态发生过程。病毒衣壳蛋白首先装配成许多呈束状排列的直径为34nm中空长管状结构,然后是病毒DNA进入管内,装有DNA的长管按一定的长度间隔断开,形成成束的核衣壳,每个核衣壳的大小约34×260nm,最后成束的核衣壳被囊膜包被形成完整的多粒包埋型病毒粒子。     

NOSTOCACEAN MACRO‐MORPHOGENESIS

A poorly understood feature of nostocacean growth and development is the formation of ordered macroscopic structures from microscopic cells, trichomes, and filaments. Using macro‐photography, time‐lapse micro‐cinematography, light and electron microscopy of Nostoc species in pure culture, it has been possible to demonstrate how motility, adhesion and aggregation of photo‐induced hormogonia result in macro‐morphogenesis of dendroid forms. Red‐light induced hormogonia from synchronized cultures aggregate rapidly on agar as tight flowing streams, in patterns responsive to the direction and quality of incident light. Unlike the even textured cell surfaces of heterocystous filaments, the cell walls of swarming hormogonia are covered with a striate mucoid layer containing pili attached to cells of adjacent hormogonia. During differentiation to an aseriate phase, cell wall fusions occur and a gelatinous matrix forms around the enlarging sub‐globose cells. Liquid suspensions of hormogonia aggregate in a solid mass following the net centripetal movement of interlaced loops of curved hormogonia attached by adhesive pili. In darkness or dim white light, compressed hormogonial aggregates form erect tree‐like (dendroid) macro‐structures by photo‐tactic reversal of streaming motility. Hormogonia within the aggregates re‐organize into streams that push upward into the light, forming structured, positively phototropic protuberances, several millimeters in length. Under weak illumination, the structures become branched with crowns of waving hormogonia. The dendroid morphology is stabilized by deposit of gelatinous material derived from successive cycles of cell‐filament development, liberation of heterocysts and formation of dormant cells and trichomes.     

论锥叠层石群（Conophyton）的形态发生—对苏北新古九顶山组一个似锥叠层石的剖析

根据对苏北新元古代九顶山组似锥叠层石标本的分析,初步揭示构成似Conophyton叠层珠微生物席可以分为两类。这两类席被作者称为“开端微生物席（first microbial mat)”和“继承微生物席（succedent microbial mat)”。它们在整个叠层石发生和发育过程中起作不同作用。Conophyton叠层石的形态发生可能与开端微生物席的造型有着密切联系,这类微生物席在叠层石形态过程中起作生长“芽”或模具作用。继承微生物席仅仅起作叠层石的增高或增大的作用,它的发育经常受环境制约。     

稀有鮈鲫眼的形态发生研究

详细观察和描述了稀有鮈鲫眼发育的形态变化,并分别对视网膜发育早期神经层、色素上皮层的厚度及眼发育后期视网膜的总厚度进行了测量。结果表明:稀有鲫眼的发生始于神经胚时期形成的眼原基,与两栖、哺乳类动物不同,其眼原基是由间脑向左右伸出的对称外突实体;在尾芽期眼原基向腹侧弯曲、侧向伸长,随后开始内陷,在尾泡期形成视杯。眼原基外层与外胚层紧贴的部分将发育为视杯的内层、神经视网膜,而眼原基其余部分将分化为视杯的外层、视网膜色素层。在尾泡期之后,视网膜色素层停止有丝分裂开始形成色素颗粒,此时视网膜神经层开始分化。视网膜这两层结构在发育早期分化的有序进行可能与早期胚胎头部内空间以及附近的间充质细胞有关。从神经胚期到尾泡期,视网膜色素层厚度由42.3±0.8μm减小到4.8±0.4μm,视网膜神经层厚度从37.1±0.2μm增加到43.7±0.6μm,而从尾鳍期到孵出期视网膜总厚度从42.7±1.2μm逐渐增加到98.3±2.1μm。与所有脊椎动物一样,稀有鲫眼的视网膜分化也是按照由内向外的顺序进行,晶状体、角膜及其他结构在孵出时已基本发育完全。     

MORPHOGENESIS OF THE SPORANGIUM OF COMATRICHA

Goodwin , Donna C. (State U. Iowa, Iowa City.) Morphogenesis of the sporangium of Comatricha. Amer. Jour. Bot. 48(2): 148–154. IIlus. 1961.—Three species of the myxomycete genus, Comatricha, were studied: Comatricha nigra, C. fimbriata, and C. elegans. The sporangia developed on living bark of Ulmus americana in moist chamber. The hypothallus is formed under the homogeneous protoplasmic mass of the sporangial initial. The fibrous threads of the hypothallus bend upward, lengthening at the apices to become the fibers of the stalk and columella. The undifferentiated protoplasm is carried upward as the stalk elongates. When the columella has attained its mature height, threads bend out from the columella and grow toward the periphery of the sporangium. These threads form the capillitium. Simultaneous with the appearance of the capillitial initials, the peridium, a delicate membrane, forms. After the capillitium is mature, the protoplast cleaves into many cells, the future spores. The peridium evanesces early in the stage of spore maturation. Cellulose is present in the stalk, capillitium, and spore walls but is not found in the peridium or hypothallus. The capillitium of these species follows a developmental pattern designated as the “Comatricha-type” by Ross (1957) from a study of Comatricha typhoides. The taxonomic implications of the sporangial developmental pattern are discussed.     

KIN-MEDIATED MORPHOGENESIS IN FACULTATIVELY CANNIBALISTIC TADPOLES

Inclusive fitness theory predicts that organisms can increase their fitness by helping or not harming relatives, and many animals modify their behavior toward kin in a manner consistent with this prediction. Morphogenesis also may be sensitive to kinship environment, particularly in species where certain individuals facultatively develop structures that can be used against conspecifics as weaponry. We tested this hypothesis by examining whether and how consanguinity affected the probability that a structurally distinctive carnivore phenotype, which is opportunistically cannibalistic, would be produced in plains spadefoot toad tadpoles (Spea bombifrons) and southern spadefoot toad tadpoles (S. multiplicata). For tadpoles of S. multiplicata, individuals were significantly more likely to express the carnivore phenotype in mixed sibship groups than in pure sibship groups. For tadpoles of S. bombifrons, individuals were significantly more likely to express the carnivore phenotype when reared alone than in pure sibship groups. Both outcomes were independent of food availability or sibship specific differences in size or growth rate, and waterborne chemical signals from nonkin were sufficient to trigger expression of the carnivore phenotype. Our results suggest that morphogenesis may be responsive to kinship environment in any species or population that occurs as multiple, environmentally induced forms (polyphenism) that differ in their ability to help or to harm others.