七株眼虫基于微卫星DNA指纹图谱的区分和关系分析

尽管以前对眼虫进行过大量的形态发育研究和基于核糖体RNA基因的系统发育分析,但对于株系之间的关系仍然知之甚少．因其形态特征有限并且易变,很难鉴定眼虫的相似种和同种内不同的株．作者利用微卫星DNA指纹图谱,在七株眼虫中扩增了七个微卫星DNA位点,成功扩增的六个微卫星引物都得到了四到八个条带．从微卫星DNA指纹图谱计算得到的相似性系数范围从0．000到0．957．根据相似性系数得到的树状结构,七株眼虫在距离为0．9346处分为三支:E．mutabilis,E．intermedia和E．gracilis．其中,

Ecophysiological characteristics of four intertidal marine macroalgae during emersion along Shantou coast of China, with a special reference to the relationship of photosynthesis and CO2

Intertidal marine macroalgae experience periodical exposures during low tide due to their zonational distribution. The duration of such emersion leads to different exposures of the plants to light and aerial CO2, which then affect the physiology of them to different extents. The ecophysiological responses to light and CO2 were investigated during emersion in two red algae Gloiopeltis furcata and Gigartina intermedia, and two brown algae Petalonia fascia and Sargassum hemiphyllum, growing along the Shantou coast of China. The light-saturated net photosynthesis in G. furcata and P. fascia showed an increase followed by slightly desiccation, whereas that in G. intermedia and S. hemiphyllum exhibited a continuous decrease with water loss. In addition, the upper-zonated G. furcata and P. fascia, exhibited higher photosynthetic tolerance to desiccation and required higher light level to saturate their photosynthesis than the lower-zonated G. intemedia and S. hemiphyllum. Desiccation had less effect on dark respiration in these four algae compared with photosynthesis. The light-saturated net photosynthesis increased with increased CO2 concentrations, being saturated at CO2 concentrations higher than the present atmospheric level in G. furcata, G. intermedia and S. hemiphyllum during emersion. It was evident that the relative enhancement of photosynthesis by elevated CO, in those three algae increased, though the absolute values of photosynthetic enhancement owing to CO2 increase were reduced when the desiccation statuses became more severe. However, in the case of desiccated P. fascia (water loss being greater than 20 %), light saturated net photosynthesis was saturated with current ambient atmospheric CO2 level. It is proposed that increasing atmospheric CO2 will enhance the daily photosynthetic production in intertidal macroalgae by varied extents that were related to the species and zonation.

黄土丘陵区植被次生演替灌木种群的土壤养分效应

研究黄土丘陵区植被次生演替灌木群落形成过程中土壤养分的变化情况。【方法】以白羊草群落为对照,选取杠柳、狼牙刺、丁香、虎榛子和柠条5种乡土树种为研究对象,测定其土壤养分含量,计算灌木群落形成变化过程中的土壤养分指数(Soil Nutrient Index,SNI),分析了各养分因子间的线性相关关系。【结果】不同灌木初期对土壤养分的适应能力大小顺序为:柠条(0.072)>狼牙刺(0.114)>杠柳(0.163)>丁香(0.172)>虎榛子(0.292)。不同植被物种群落土壤SNI值大小顺序为:虎榛子群落(0.979)>狼牙刺群落(0.535)>柠条群落(0.457)>丁香群落(0.341)>杠柳群落(0.333)>白羊草群落(0.145)。从不同灌木群落形成过程所产生的土壤养分改善效应来看,各参试群落相对于白羊草群落土壤养分的增幅分别为:虎榛子(4.740倍)、狼牙刺(2.909倍)、柠条(2.661倍)、杠柳(1.169倍)和丁香(1.168倍)。各土壤养分因子间除土壤全磷与有效磷和有效钾的相关性不显著外,其余各土壤养分因子间均表现出极显著的线性相关关系(P<0.01)。【结论】不同灌木种群所需的适宜土...

几类处在关键进化地位藻类的TIM基因和糖酵解途径的研究

糖酵解作为细胞的重要的基本代谢途径广泛存在于各类生物中。但参与该途径的tim基因／酶和整个途径在细胞中的区室定位情况在一些处在关键进化地位的藻类中还存在许多未知或争议。本文首先对参与该途径的一个重要酶――磷酸丙糖异构酶（TIM）在两种不同营养方式的眼虫上进行了鉴定和序列结构分析，并结合了包括绿藻、红藻和动基体类等在内的其它生物的数据进行了分子系统分析；其次，对该途径在绿藻类的衣藻细胞中的区室定位情况进行了研究，并对该特殊的区室定位途径的进化进行了探讨。得到了如下结果和结论： 1）通过3’与5’-RACE实验，在光合型眼虫Euglena gracilis和Euglena intermedia和腐生型眼虫Astasia longa中各获得了一长一短两个TIM的全长cDNA序列，同时通过基因组DNA-PCR和序列搜索，还获得了两种绿藻和红藻的tim基因序列。前导序列分析显示眼虫的两个cDNA分别编码定位到胞质的cTIM和定位到叶绿体的cpTIM或质体的pTIM。腐生眼虫A. longa的pTIM与光合型眼虫E. gracilis的cpTIM高度相似，其前导序列也具有眼虫典型的核编码叶绿体蛋白质的典型特征；两类不同营养型眼虫的成熟TIM间的同源性达91.6％，并且具有其它TIM所共有的活性中心氨基酸和保守的序列motifs。这表明A. longa的pTIM确实是定位于质体、具有生物活性的cpTIM的同工酶，并提示A. longa的质体还具有与TIM相关的代谢功能（例如脂肪酸的合成），而不仅仅是一个叶绿体的“残迹”。 TIM的序列比对和分子系统分析结果显示：眼虫类和红藻类的TIM共有一个由两个氨基酸组成的插入；更重要的是，眼虫类TIM既没有与被认为与它共祖的动基体类的TIM聚在一起，又没有与被认为为其提供叶绿体（经二次内共生）的绿藻的TIM聚在一起，而是与红藻TIM聚为一枝。这提示眼虫与红藻间在进化历史上可能曾经有过基因交流。 2）采用生物信息学手段结合分子生物学实验，对衣藻基因组和转录组中参与糖酵解相关基因／酶进行了鉴定、定位预测和表达水平分析，结果表明：与其它极大多数的真核生物不同，衣藻细胞质中不具有完整的糖酵解途径，尽管该途径的后三步主要发生在胞质中，但前七步则是发生在叶绿体中的。 分子系统分析表明衣藻叶绿体中参与前6步和细胞质中参与最后2步的糖酵解酶都是胞质型起源，其中参与第4步的FBA更像是由很早时期的胞质型基因重复而来的；而第7步的PGK是由内共生形成叶绿体的蓝细菌的水平基因转移而来。这表明衣藻胞质中所缺少的糖酵解酶是一种次生性丢失的结果，而非原始的特征；其叶绿体中的糖酵解步骤应该是由于原有胞质型糖酵解酶的基因重复之后重新定位或者直接重新定位到叶绿体中，以及内共生产生叶绿体时由蓝细菌的水平基因转移所致。

锦鸡儿属防风固沙树种的离体培养试验

以锦鸡儿属中柠条锦鸡儿(Caraganakorshinskii)、中间锦鸡儿(C.intermedia)和树锦鸡儿(C.arborescens)种子为外植体,通过对增殖阶段和生根阶段培养基的筛选,探讨了细胞分裂素、生长素、矿质营养和活性炭对这3个树种不同发育阶段的影响。结果表明:(1)继代增殖阶段:柠条锦鸡儿、中间锦鸡儿和树锦鸡儿最佳的基本培养基为MS,最适合的激素浓度配比中,柠条锦鸡儿用BA2mg·L-1+GA2mg·L-1分生率最高;中间锦鸡儿用BA2mg·L-1+GA1mg·L-1分生率最高;树锦鸡儿用BA2mg·L-1+NAA0.1mg·L-1分生率最高。蔗糖是最好的碳源。(2)生根阶段:柠条锦鸡儿诱导生根的适合培养基为1/4MS+NAA0.1mg·L-1和MS+NAA0.1mg·L-1,中间锦鸡儿为1/4MS+NAA0.1mg·L-1,树锦鸡儿为1/2MS+NAA0.1mg·L-1和1/4MS+NAA0.1mg·L-1。活性炭对生根率无显著影响,但普遍增加了根的条数和根的长度。气培生根以MS+IBA50mg·L-1+3%白糖处理较好。

Bioorganic/inorganic hybrid composition of sponge spicules: Matrix of the giant spicules and of the comitalia of the deep sea hexactinellid Monorhaphis

The giant basal spicules of the siliceous sponges Monorhaphis chuni and Monorhaphis intermedia (Hexactinellida) represent the largest biosilica structures on earth (up to 3 m long). Here we describe the construction (lamellar organization) of these spicules and of the comitalia and highlight their organic matrix in order to understand their mechanical properties. The spicules display three distinct regions built of biosilica: (i) the outer lamellar zone (radius: >300 mu m), (ii) the bulky axial cylinder (radius: <75 mu m), and (iii) the central axial canal (diameter: <2 mu m) with its organic axial filament. The spicules are loosely covered with a collagen net which is regularly perforated by 7-10 mu m large holes; the net can be silicified. The silica layers forming the lamellar zone are approximate to 5 mu m thick; the central axial cylinder appears to be composed of almost solid silica which becomes porous after etching with hydrofluoric acid (HF). Dissolution of a complete spicule discloses its complex structure with distinct lamellae in the outer zone (lamellar coating) and a more resistant central part (axial barrel). Rapidly after the release of the organic coating from the lamellar zone the protein layers disintegrate to form irregular clumps/aggregates. In contrast, the proteinaceous axial barrel, hidden in the siliceous axial cylinder, is set up by rope-like filaments. Biochemical analysis revealed that the (dominant) molecule of the lamellar coating is a 27-kDa protein which displays catalytic, proteolytic activity. High resolution electron microscopic analysis showed that this protein is arranged within the lamellae and stabilizes these surfaces by palisade-like pillars. The mechanical behavior of the spicules was analyzed by a 3-point bending assay, coupled with scanning electron microscopy. The load-extension curve of the spicule shows a biphasic breakage/cracking pattern. The outer lamellar zone cracks in several distinct steps showing high resistance in concert with comparably low elasticity, while the axial cylinder breaks with high elasticity and lower stiffness. The complex bioorganic/inorganic hybrid composition and structure of the Monorhaphis spicules might provide the blueprint for the synthesis of bio-inspired material, with unusual mechanical properties (strength, stiffness) without losing the exceptional properties of optical transmission. (C) 2007 Elsevier Inc. All rights reserved.

中国海豆蟹科Family Pinnotheridae分类学研究

本文根据中国科学院海洋研究所收藏的豆蟹科标本和国内外相关文献，进行了中国海域豆蟹科的分类学研究。作者克服了豆蟹科分类难度大，研究积累较少，种的界限不清等困难，在短期内初步查清了中国海域豆蟹科种类及分布情况，共记述5亚科12属 40种。发现4新记录属，9新记录种，和豆蟹属1未定种Pinnotheres sp.，丰富了中国海豆蟹科区系内容，列出了共栖种中国海域全部记录过的宿主。 作者对鉴定过程中出现的疑难问题：“中型三强蟹Tritodynamia intermedia Shen, 1935是否为霍氏三强蟹 Tritodynamia horvathi Nobili, 1905的同物异名” 进行了细致比较、研究，否定了通行多年的Sakai（1976）的“T. intermedia Shen为T. horvathi Nobili的次异名”的结论，肯定了二者均为有效种。 对中国海域豆蟹科种类地理分布初步研究表明其分布与日本海域和东南亚海域都有相似之处，但有显著不同：仅发现于中国海域而未见于日本海域的豆蟹属Pinnotheres多达8种：涨腹豆蟹Pinnotheres excussus Dai et al., 1980，球豆蟹Pinnotheres pilulus Dai et al., 1980，锯颚豆蟹Pinnotheres serrignathus Shen, 1932，宽豆蟹Pinnotheres dilatatus Shen, 1932，青岛豆蟹Pinnotheres tsingtaoensis Shen, 1932，海阳豆蟹Pinnotheres haiyangensis Shen, 1932，钝颚豆蟹Pinnotheres obtusidentata（Dai et al., 1980），光豆蟹Pinnotheres luminatus Dai et al., 1980）；仅发现于中国海域的三强蟹属Tritodynamia有4种：福建三强蟹Tritodynamia fujianensis Chen, 1979，长腿三强蟹Tritodynamia longipropodum Dai et al., 1980，宽身三强蟹 Tritodynamia dilatatum Yang et Sun,1996和海南三强蟹 Tritodynamia hainanensis Dai et al.g, 1980；而未发现于中国海域的日本特有种多达13种。结果表明这一类群由于共栖和地域分化程度较高乃至地区性特有种数显著较多。 论文通过对豆蟹科系统分类和初步的动物地理学研究，搞清了中国海豆蟹科的种和分布、多样性及其宿主等基本情况。为今后研究豆蟹科种类生物学、生态学特性提供了基础资料。

Identification of a silicatein(-related) protease in the giant spicules of the deep-sea hexactinellid Monorhaphis chuni

Silicateins, members of the cathepsin L family, are enzymes that have been shown to be involved in the biosynthesis/condensation of biosilica in spicules from Demospongiae (phylum Porifera), e. g. Tethya aurantium and Suberites domuncula. The class Hexactinellida also forms spicules from this inorganic material. This class of sponges includes species that form the largest biogenic silica structures on earth. The giant basal spicules from the hexactinellids Monorhaphis chuni and Monorhaphis intermedia can reach lengths of up to 3 m and diameters of 10 mm. The giant spicules as well as the tauactines consist of a biosilica shell that surrounds the axial canal, which harbours the axial filament, in regular concentric, lamellar layers, suggesting an appositional growth of the spicules. The lamellae contain 27 kDa proteins, which undergo post-translational modification (phosphorylation), while total spicule extracts contain additional 70 kDa proteins. The 27 kDa proteins cross-reacted with anti-silicatein antibodies. The extracts of spicules from the hexactinellid Monorhaphis displayed proteolytic activity like the silicateins from the demosponge S. domuncula. Since the proteolytic activity in spicule extracts from both classes of sponge could be sensitively inhibited by E-64 (a specific cysteine proteinase inhibitor), we used a labelled E-64 sample as a probe to identify the protein that bound to this inhibitor on a blot. The experiments revealed that the labelled E-64 selectively recognized the 27 kDa protein. Our data strongly suggest that silicatein(-related) molecules are also present in Hexactinellida. These new results are considered to also be of impact for applied biotechnological studies.

The unique skeleton of siliceous sponges (Porifera; Hexactinellida and Demospongiae) that evolved first from the Urmetazoa during the Proterozoic: a review

Sponges (phylum Porifera) had been considered as an enigmatic phylum, prior to the analysis of their genetic repertoire/tool kit. Already with the isolation of the first adhesion molecule, galectin, it became clear that the sequences of sponge cell surface receptors and of molecules forming the intracellular signal transduction pathways triggered by them, share high similarity with those identified in other metazoan phyla. These studies demonstrated that all metazoan phyla, including Porifera, originate from one common ancestor, the Urmetazoa. The sponges evolved prior to the Ediacaran-Cambrian boundary (542 million years ago [myr]) during two major "snowball earth events", the Sturtian glaciation (710 to 680 myr) and the Varanger-Marinoan ice ages (605 to 585 myr). During this period the ocean was richer in silica due to the silicate weathering. The oldest sponge fossils (Hexactinellida) have been described from Australia, China and Mongolia and are thought to have existed coeval with the diverse Ediacara fauna. Only little younger are the fossils discovered in the Sansha section in Hunan (Early Cambrian; China). It has been proposed that only the sponges possessed the genetic repertoire to cope with the adverse conditions, e.g. temperature-protection molecules or proteins protecting them against ultraviolet radiation. The skeletal elements of the Hexactinellida (model organisms Monorhaphis chuni and Monorhaphis intermedia or Hyalonema sieboldi) and Demospongiae (models Suberites domuncula and Geodia cydonium), the spicules, are formed enzymatically by the anabolic enzyme silicatein and the catabolic enzyme silicase. Both, the spicules of Hexactinellida and of Demospongiae, comprise a central axial canal and an axial filament which harbors the silicatein. After intracellular formation of the first lamella around the channel and the subsequent extracellular apposition of further lamellae the spicules are completed in a net formed of collagen fibers. The data summarized here substantiate that with the finding of silicatein a new aera in the field of bio/inorganic chemistry started. For the first time strategies could be formulated and experimentally proven that allow the formation/synthesis of inorganic structures by organic molecules. These findings are not only of importance for the further understanding of basic pathways in the body plan formation of sponges but also of eminent importance for applied/commercial processes in a sustainable use of biomolecules for novel bio/inorganic materials.