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关键词： environmental factors   monitoring   Patella ferruginea   population viability analysis   recruitment  

摘要： Global climate change and other human-induced alterations of the environment are causing a significant loss in biodiversity. Among the many species affected is the giant limpet Patella ferruginea, considered as the most endangered marine invertebrate within the Western Mediterranean basin. The results of a 10-year monitoring programme in an updated population viability analysis (PVA) model are provided, which indicate the unlikeliness of the population in Ceuta facing extinction within the next 50 years. Evidence is provided for the possible role of this population as a source population for other sink populations in the Alboran Sea. Large interannual variations in recruitment have been recorded, and the general linear model (GLM) indicates the influence of chlorophyll and temperature on recruitment rates. These results inform conservation strategies for this flagship species.

关键词： Oocyte   Egg envelope   Cortical alveoli   Sperm   Acrosome formation   Fertilization mechanism   Ultrastructure   Polychaete  

摘要： Spiophanes uschakowi is a common polychaete living in tubes in sandy sediments in shallow waters of the Sea of Japan. Females and males release their gametes into the water where fertilization and holopelagic, planktotrophic larval development occur. In females, oogenesis is intraovarian: vitellogenesis occurs when the oocytes grow in paired ovaries attached to genital blood vessels in fertile segments. The developed oocytes are accumulated in the coelomic cavity prior to spawning. The newly released oocytes are lentiform, 185-200 mu m in diameter, with honey-combed envelopes 5-7 mu m thick. Each oocyte has 41-49 cortical alveoli regularly arranged in a peripheral circle, a nucleus 80-83 mu m in diameter, and a single nucleolus about 30 mu m in diameter. In males, spermatogonia proliferate in testes and the rest of spermatogenesis occurs in the coelomic cavity. During spermiogenesis, the acrosomal vesicle migrates from the posterior to the anterior part of the spermatid. The spermatozoa are ect-aquasperm with a plate-like acrosome 0.58 +/- 0.06 mu m thick and 2.14 +/- 0.13 mu m in diameter, barrel-shaped nucleus 2.23 +/- 0.13 mu m long and 3.18 +/- 0.13 mu m in diameter, short midpiece 0.93 +/- 0.09 mu m long with five spherical mitochondria, two centrioles and one small lipid droplet, and a flagellum 62-63 mu m long with 9 x 2 + 2 organization of microtubules. The acrosome is a complex heterogeneous structure with 4-6 subspherical apical bodies, and numerous small branched basal cisternae. The anterior end of the nucleus is truncate, while its posterior end has wide shallow depressions accommodating the mitochondria. The centrioles are situated in the center of the midpiece between mitochondria and oriented obliquely to each other. The structure of the gametes of broadcast-spawning spionids is reviewed and the roles of surface granules in species-specific attraction of sperm toward eggs by releasing chemical signals (sperm chemotaxis), and cortical alveoli as a pla

关键词： Amphibians   Marsupial   Gastrulation   Xenopus laevis   frogs   Precocious Development   Pouch   oogenesis   Reproduction  

摘要： The study of oogenesis and early development of frogs belonging to the family Hemiphractidae provide important comparison to the aquatic development of other frogs, such as Xenopus laevis, because reproduction on land characterizes the Hemiphractidae. In this review, the multinucleated oogenesis of the marsupial frog Flectonotus pygmaeus (Hemiphractidae) is analyzed and interpreted. In addition, the adaptations associated with the incubation of embryos in the pouch of the female marsupial frog Gastrotheca riobambae (Hemiphractidae) and the embryonic development of this frog are summarized. Moreover, G. riobambae gastrulation is compared with the gastrulation modes of Engystomops randi and Engystomops coloradorum (Leptodactylidae);Ceratophrys stolzmanni (Ceratophryidae);Hyalinobatrachium fleischmanni and Espadarana callistomma (Centrolenidae);Ameerega bilinguis, Dendrobates auratus, Epipedobates anthonyi, Epipedobates machalilla, Epipedobates tricolor, and Hyloxalus vertebralis (Dendrobatidae);Eleutherodactylus coqui (Terrarana: Eleutherodactylidae), and X. laevis (Pipidae). The comparison indicated twomodes of frog gastrulation. In X. laevis and in frogswith aquatic reproduction, convergent extension begins during gastrulation. In contrast, convergent extension occurs in the post-gastrula of frogswith terrestrial reproduction. These twomodes of gastrulation resemble the transitions toward meroblastic cleavage found in ray-finned fishes (Actinopterygii). In spite of this difference, the genes that guide early development seemto be highly conserved in frogs. I conclude that the shift of convergent extension to the post-gastrula accompanied the diversification of frog egg size and terrestrial reproductive modes. (c) 2018 Elsevier B.V. All rights reserved.

关键词： GLUT proteins   GLUT4 translocation   insulin action  

摘要： The structure and function of glucose transporters of the mammalian GLUT family of proteins has been studied over many decades, and the proteins have fascinated numerous research groups over this time. This interest is related to the importance of the GLUTs as archetypical membrane transport facilitators, as key limiters of the supply of glucose to cell metabolism, as targets of cell insulin and exercise signalling and of regulated membrane traffic, and as potential drug targets to combat cancer and metabolic diseases such as type 2 diabetes and obesity. This review focusses on the use of chemical biology approaches and sugar analogue probes to study these important proteins.

关键词： 5E教学模式   概念模型   生命活动调节  

摘要： 基于5E教学模式对人教版高中生物学必修3《稳态与环境》模块第2章"动物和人体生命活动的调节"一章内容进行核心概念教学设计。5E模式是被教育界普遍认可的有效的教学模式,而核心概念的教学是高中生物教学最重要的内容,通过结合概念模型的构建过程实施5E教学模式,完成核心概念的教学。

关键词： 鄂西   生态旅游区   大型底栖动物   群落结构   生物评价指数  

摘要： 鄂西水系是国家级水源保护区,也是湖北省重要的生态旅游区。为了解鄂西水生态健康状况,于2014年10月~2017年1月不同时段在宜昌国家可持续发展实验示范区卷桥河(J)、清江利川段(Q)、宜昌市水源地黄柏河(H)和丹江口入库河流天河郧西段(T)开展了底栖动物群落特征研究。研究表明:4个河段共采集到大型底栖动物5门8纲18目61科。基于底栖动物指示种耐污性及其丰度占比分析,表明J、Q和T三河流污染程度沿水流方向呈加重趋势,而H水体健康状况整体较好。运用FBI和SIGNAL底栖生物评价指数,显示四条河流健康程度沿水流方向均呈下降趋势,但H变化趋势平缓,结果表明H水体上下游均处于较健康状态,其他3条河流上游或源头水体健康状况良好,下游受到较重污染。对主要环境因子(TP、NH_3-N、COD_(Mn)和TN)做主成分分析表明,轴1的解释率达到65. 1%,表明轴1可以有效表征主要环境压力梯度。FBI和SIGNAL指数与轴1线性拟合度均较高,表明二者在鄂西河流水生态健康评估中可作为快速生物评价指数。

关键词： 植物精油   新型饲料添加剂   动物   生物学活性   免疫力  

摘要： 植物精油是植物产生的挥发性液体,通常具有香气。研究中发现植物精油含有多种活性成分,作为新型饲料添加剂有抗菌、抗氧化、抗炎、提高动物免疫力等作用。因此,本文就植物精油的主要生物学活性及其在动物生产中的应用进行综述。