Precise timing of the last interglacial period from mass spectrometric determination of thorium-230 in corals

The development of mass spectrometric techniques for determination of (230)Th abundance has made it possible to reduce analytical errors in (238)U-(234)U-(230)Th dating of corals even with very small samples. Samples of 6 x 10(8) atoms of (230)Th can be measured to an accuracy of +/-3 percent (2sigma) and 3 x 10(10) atoms of (230)Th can be measured to an accuracy of +/-0.2 percent. The time range over which useful age data on corals can be obtained now ranges from about 50 to about 500,000 years. For young corals, this approach may be preferable to (14)C dating. The precision with which the age of a coral can now be determined should make it possible to critically test the Milankovitch hypothesis concerning Pleistocene climate fluctuations. Analyses of a number of corals that grew during the last interglacial period yield ages of 122,000 to 130,000 years. The ages coincide with, or slightly postdate, the summer solar insolation high at 65 degrees N latitude which occurred 128,000 years ago. This supports the idea that changes in Pleistocene climate can be the result of variations in the distribution of solar insolation caused by changes in the geometry of the earth's orbit and rotation axis.     

C14 族R2R3鄄MYB 基因调控杨树抗锈菌过敏性反应

由落叶松-杨栅锈菌引起的杨树叶锈病分布广泛,危害严重。为探究杨树C14族R2R3-MYB基因在杨树抗锈菌过敏性反应中的调控作用,对接种了落叶松-杨栅锈菌E4强致病性生理小种的2种杨树叶片进行症状观察、感病指数判定并对2种杨树C14族共6条R2R3-MYB基因表达量变化情况进行分析。接种7 dpi后,弱感病性树种杂交杨叶片产生的夏孢子堆数量显著少于感病树种欧美杨。杂交杨叶片4 dpi开始出现过敏性反应症状,欧美杨未观察到类似症状。表明过敏性反应可有效阻止锈菌夏孢子堆形成,降低杨树感病性。杂交杨与欧美杨R2R3-MYB基因表达量变化趋势相反,预测杨树C14族R2R3-MYB基因为杨树与病原互作过程中调控过敏性反应的正向调控因子。本研究为进一步系统研究杨树R2R3-MYB基因与过敏性反应的调控机理及杨树抗病育种工作提供理论依据。      

稻瘟病菌一个假定的α-1,2-甘露糖苷酶生物信息学分析

对稻瘟病菌一个假定的α-1,2-甘露糖苷酶MgManⅠ生物信息学进行分析的结果表明,该蛋白与海枣曲霉、桔青霉等丝状真菌的已知α-1,2-甘露糖苷酶(EC 3.2.1.113)氨基酸序列具有高度同源性,并具有其相同的活性中心位点.基序分析表明,该蛋白可能含有4个N-糖基化位点、3类19个磷酸化位点和12个N-肉豆蔻酰位点.该蛋白的相对分子质量预测为58.2 ku,理论等电点pI为5.17,并且为细胞外分泌蛋白,信号肽剪切位点为21A和22S之间.系统发育分析表明:MgManⅠ与丝状真菌中的海枣曲霉、桔青霉α-1,2-甘露糖苷酶之间亲缘关系最近,形成一大类;动物的α-1,2-甘露糖苷酶与植物的α-1,2-甘露糖苷酶分别聚成二大类;酿酒酵母α-1,2-甘露糖苷酶ScManⅠ与丝状真菌不同,单独成为一类.进一步以已知结构的PcManⅠ为模板,通过同源建模得到的三维结构图形基本反映了MgManⅠ的空间构象,为深入研究该蛋白的生化特性和生物学功能奠定了基础.     

Paleoceanography of coral reefs in the hawaiian-emperor chain

The fossil record of shallow marine organisms in the Hawaiian Archipelago and Emperor seamount chain indicates that reef corals were absent during the first half of the Tertiary. Their appearance during the early Oligocene, 34 million years ago, is associated with several paleoceanographic events that appear to have combined to intensify gradually gyral surface currents in the north Pacific. This association suggests that corals were absent in the early Tertiary because of isolation of the Hawaiian Archipelago from the Indo-West Pacific (IWP), the center of reef coral abundance and diversity in the Pacific. Today, the number of species of reef corals in Hawaii is less than 10 percent of the number of species in the IWP. Since their initial colonization, reef corals have been present continuously in the Hawaiian Archipelago, although not without taxonomic change. Episodes of extinction and recolonization are the most likely cause of change in species composition. Recolonization from the IWP may also explain the low rate of endemism (about 20 percent) in the present-day coral fauna.     

Distribution of Labeled Carbon in Reef-Building Corals with and without Zooxanthellae

The uptake and distribution of carbon-14 in two reef-building corals, Manicina areolata and Montastrea annularis, were studied by radioautographic methods. Experiments on colonies with and without zooxanthellae were run in light and in darkness. We suggest that corals cannot derive any effective nutrition from their zooxanthellae, and that the physiological response of corals to the presence of zooxanthellae is due to the secretion of trace amounts of vitamin-like or hormone-like substances by the algal symbionts, and not to their food value per se.     

不同方法提取珊瑚总蛋白质的比较

以海南省近岸海域的鼻形鹿角珊瑚(Acropora nasuta)和箭排孔珊瑚(Seriatopora hystrix)2种硬珊瑚为研究对象,比较了TRIzol试剂提取法和BP-酚提取法在珊瑚蛋白质提取量、双向蛋白点数量和分布上的差异。结果表明,BP-酚抽提法的蛋白质得率相对较高。通过1-DE及2-DE电泳比较分析发现,2种方法获得的蛋白样品存在较大差异。BP-酚抽提法能够获得更多蛋白条带和点数,并且具有较少的拖尾现象。在低相对分子质量蛋白的提取方面,TRIzol试剂提取法具有优势;在高相对分子质量的提取方面,BP-酚抽法具有明显优势。研究结果有望为硬珊瑚的蛋白质组学研究奠定一定的基础。     

Chitin in sea anemone shells

Chitin, which is widely distributed among life forms, is well documented in the coelenterate class Hydrozoa and is contained in one member of class Scyphozoa. In class Anthozoa, hard corals synthesize it but soft corals do not. Chitin was identified by infrared spectrophotometry in the trochoid shell of the actinian Stylobates. It constitutes 1.7 percent of the shell by weight, the rest probably being protein. The ability of sea anemones to synthesize chitin is there by confirmed.     

我国淡水养殖动物主要致病性水霉菌病原的分析

应用ITS(internal transcribed spacer,ITS)区分子系统发育进化分析法和限制性片段长度多态性分析法(Restriction Fragment Length Polymorphism,RFLP)相结合,对近年来分别采集于中国上海、江苏、江西、四川、河北、浙江、湖北等7个主要淡水养殖区的60株疑似致病性水霉菌(Saprolegnia)进行鉴定分类,并系统分析了我国已报道的致病性水霉菌的分类情况,比较了分别分离自鱼体和卵的多子水霉的生物学特性。研究结果表明,60株疑似水霉菌分为10个基因型,其ITSLPCR-LRFLP谱型一致属于典型多子水霉(Saprolegniales ferax)、寄生水霉(Saprolegniales parasitia)和澳大利亚水霉(S.australis)分组类型;ITS系统发育进化分析结果显示,我国致病性水霉菌以多子水霉和寄生水霉为主,二者为我国淡水养殖主要的致病性水霉菌病原。此外,对鱼体和卵来源的多子水霉生物学特征进行比对后发现,二者没有明显差异,同一致病菌株既可感染鱼体也可感染卵。此研究的开展丰富了我国致病性水霉菌分类统计的生物学资料,为水霉病预警和药物防治技术的开发提供了重要的参考价值。     

回头岸礁区4 种造礁珊瑚中可培养细菌的多样性

采用稀释涂布平板法,分离三亚鹿回头岸礁区4种造礁珊瑚及其周围海水中的细菌,并基于16S r RNA基因序列进行了系统发育分析,从而探讨造礁珊瑚中可培养细菌的物种多样性。从澄黄滨珊瑚(Porites lutea)、鹿角珊瑚(Acropora sp.)、盔形珊瑚(Galaxea sp.)、扁脑珊瑚(Platygyra sp.)样品中分别分离获得细菌60、61、54、20株,从珊瑚周边海水中分离获得细菌31株。16S r RNA基因序列分析表明,珊瑚来源的细菌分布于放线菌门(Actinobacteria)、α-变形菌纲(Alphaproteobacteria)、γ-变形菌纲(Gammaproteobacteria)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)。在属级水平上对4种珊瑚及海水来源细菌群落组成分析,发现在4种珊瑚中均有分布的属有3个,为Brachybacterium、Microbacterium和Ruegeria,珊瑚来源细菌类群有一定差异。同时发现4种珊瑚来源细菌与海水来源细菌类群差异较大。在分离的菌株中,有7株菌与已有效描述的细菌物种典型菌株的全长16S r RNA基因相似性低于97%,代表着潜在新属或新种。试验结果表明,三亚鹿回头岸礁区珊瑚中存在较为丰富的细菌多样性,并潜藏较多的新物种资源。     

Community structure of coral reefs on opposite sides of the isthmus of panama

Competition for space amon reef corals includes interspecific destruction by extracoelenteric digestion., rapid growth. and Overtopping. No Caribbean species excela in all strategies, and on western Caribbean coral reefs there is a positive correlation between coral abudance and diversity. On eastern Pacific coral reefs, however. Pocillopora damicornis excludes other corals, and on these reefs there is an inverse relation between coral abundance and diversity, except in areas where distrubances, such as Acanthaster predation offset space monopolization.     

Complex diel cycles of gene expression in coral-algal symbiosis

Circadian regulation of plant-animal endosymbioses is complicated by a diversity of internal and external cues. Here, we show that stress-related genes in corals are coupled to the circadian clock, anticipating major changes in the intracellular milieu. In this regard, numerous chaperones are "hard-wired" to the clock, effectively preparing the coral for the consequences of oxidative protein damage imposed by symbiont photosynthesis (when O(2) > 250% saturation), including synexpression of antioxidant genes being light-gated. Conversely, central metabolism appears to be regulated by the hypoxia-inducible factor system in coral. These results reveal the complexity of endosymbiosis as well as the plasticity regulation downstream of the circadian clock.     

Discovery of symbiotic nitrogen-fixing cyanobacteria in corals

Colonies of the Caribbean coral Montastraea cavernosa exhibit a solar-stimulated orange-red fluorescence that is spectrally similar to a variety of fluorescent proteins expressed by corals. The source of this fluorescence is phycoerythrin in unicellular, nonheterocystis, symbiotic cyanobacteria within the host cells of the coral. The cyanobacteria coexist with the symbiotic dinoflagellates (zooxanthellae) of the coral and express the nitrogen-fixing enzyme nitrogenase. The presence of this prokaryotic symbiont in a nitrogen-limited zooxanthellate coral suggests that nitrogen fixation may be an important source of this limiting element for the symbiotic association.     

广西家蚕核型多角体病毒株gp64基因 克隆与序列分析

[目的]了解广西家蚕核型多角体病毒(Bombyxmori nucleopolyhedrovirus,BmNPV)毒株gp64基因的保守性,并掌握其具体的突变位点,为研究核型多角体病毒(NPV)种内的微进化模式提供参考依据.[方法]对广西不同桑蚕产区的19株BmNPV毒株进行gp64基因克隆与测序,分析完整开放阅读框(ORF)序列的同源性和单核苷酸多态性,并构建基于gp64基因的遗传进化树.[结果]广西BmNPV毒株的gp64基因ORF序列不一致,存在1590、1593和1599 nt三种类型,是由于第94~96位缺失GCG或第97~102位插入GCGCCG所致,且插入核苷酸突变仅在广西BmNPV毒株中出现.仅GXSL毒株与T3毒株的核苷酸及其推导氨基酸序列同源性均达100.0%,其余18株毒株与T3毒株的核苷酸序列同源性在98.5%~99.2%,其推导氨基酸序列同源性在98.7%~99.6%.19株广西BmNPV毒株被分为两个亚群(cladeⅠ和cladeⅡ),其中11株独立形成cladeⅡ,7株独立形成cladeⅠ中的一个亚群;广西毒株在多个位点出现同义核苷酸突变,呈一定的规律性.[结论]广西BmNPV毒株的gp64基因具有遗传多样性,在遗传进化上较独立,插入突变显示出地域特点.     

漳州紫泥围垦区海水中弧菌类群研究

[目的]调查紫泥围垦区海水中弧菌类群组成,为相关病害的预防和控制提供有价值的资料。[方法]采用TCBS(Thiosulfate Citrate Bile Salts Sucrose)培养基从紫泥围垦区海水中分离得到48株细菌,应用16S rRNA基因-RFLP(限制性酶切图谱多样性分析)、16S rRNA基因序列及系统进化分析方法对48个菌株进行分子鉴定。[结果]紫泥围垦区海水弧菌包括4个类群,分别为group 1-Vibrio crassostreae,占14.6%;group 2-V.atlanticus,占58.3%;group 3-V.splendidus,占12.5%;group 4-V.lentus,占14.6%。4类弧菌皆属于V.splendidus进化分支,能引起虾类、贝类动物的疾病。[结论]该研究明确了特定时间段内紫泥围垦区弧菌为V.splendidus相关的类群,对于针对性地防控这些弧菌引起的养殖动物疾病具有一定的指导价值。     

杨树湿心材病致病细菌的分离、鉴定和侵染途径

采用常规的组织分离法从杨树湿心材病发病心材组织中分离到10个优势菌株,将菌株分别回接健康杨树实生苗,通过侵染症状、发病率和发病程度等测定致病性,结果发现2-16号菌株能引起典型的湿心材症状,即心材变色并腐烂。对2-16菌株形态特征、生理生化进行了分析,2-16菌株16SrDNA基因序列与胡萝卜软腐果胶杆菌胡萝卜软腐亚种(Pectobacterium carotovorumsubsp.carotovorum)NBRC 14082菌株报告的序列相似度为99%。采用Mega5.0软件以相近序列构建的进化树中,2-16菌株和NBRC 14082菌株聚在同一进化枝上。鉴定2-16号致病菌为胡萝卜软腐果胶杆菌胡萝卜软腐亚种。以温室栽培的当年生中石7杨树实生苗为接种材料,将2-16号致病菌分别通过4种方式进行侵染接种,结果表明:茎刻伤和茎注射2-16致病菌株均能引起杨树植株发病,茎注射法发病率、病斑扩散长度和发病指数均高于茎刻伤法,而叶接和灌根接种2-16致病菌株均不能使杨树感病,表明茎部伤口感染是该致病菌侵染杨树的主要途径。     

Molecular epidemiological study of animal rabies in Kazakhstan

Rabies is a serious public health issue in Kazakhstan, with high economic impact and social burden.  As part of a routine surveillance, 31 rabies-positive brain specimens taken from livestock (cattle) and carnivores (dogs, foxes, and cats) during 2013–2021 were subject to viral sequencing.  Phylogenetic and Bayesian analysis were performed using obtained rabies virus (RABV) sequences.  All 31 strains of RABV candidate belonged to the Cosmopolitan clade, of which 30 strains belonged to steppe-type subclade, and 1 dog strain belonged to Other subclade.  The 31 strains did not diverge from RABV strains in Kazakhstan and neighboring countries, including Russia, Mongolia, and China, suggesting that animal rabies has close relationship and transmission between borders.  Fox-originated strains and cattle strains shared similar sequence signature, and some animal rabies cases had space–time intersection, showing that infected foxes were a major transmission source of cattle rabies in different Kazakhstan regions.  Besides, free-roaming dogs played a pivotal role in rabies epizootics of cattle in Kazakhstan.  The recent spread of animal rabies presents an increasing threat to public health, and provides updated information for improving current control and prevention strategies at the source for Kazakhstan and neighboring countries.     

One-third of reef-building corals face elevated extinction risk from climate change and local impacts

The conservation status of 845 zooxanthellate reef-building coral species was assessed by using International Union for Conservation of Nature Red List Criteria. Of the 704 species that could be assigned conservation status, 32.8% are in categories with elevated risk of extinction. Declines in abundance are associated with bleaching and diseases driven by elevated sea surface temperatures, with extinction risk further exacerbated by local-scale anthropogenic disturbances. The proportion of corals threatened with extinction has increased dramatically in recent decades and exceeds that of most terrestrial groups. The Caribbean has the largest proportion of corals in high extinction risk categories, whereas the Coral Triangle (western Pacific) has the highest proportion of species in all categories of elevated extinction risk. Our results emphasize the widespread plight of coral reefs and the urgent need to enact conservation measures.     

Dust: a diagnostic of the hydrologic cycle during the last glacial maximum

Dust concentrations in ice of the last glacial maximum (LGM) are high in ice cores from Greenland and Antarctica. The magnitude of the enhancements can be explained if the strength of the hydrologic cycle during the LGM was about half of that at present. This notion is consistent with a large decrease (5 degrees Celsius) in ocean temperature during the LGM, as recently deduced from measurements of strontium and calcium in corals.     

寄生蜂28S rDNA D2 区序列及其分子系统学研究

对棉铃虫齿唇姬蜂Campoletis chlorideae Uchida、腰带长体茧蜂Macrocentrus cingulum Brischke和麦蚜茧蜂 Ephedrusplagia-tor（Nees）3种寄生蜂28S rDNA D2区序列进行了聚合酶链式反应（PCR）,检索了GenBank核酸序列库中姬蜂总科和小蜂总科的其它26种寄生蜂的相应序列,利用29种寄生蜂及2种弹尾目昆虫28S rDNA D2区序列对寄生蜂进行了系统进化分析.结果表明,3种寄生蜂28S rDNA D2区序列与同一亚科的其他种相似性达90%以上.3种寄生蜂中,腰带长体茧蜂和麦蚜茧蜂与弹尾目昆虫的遗传距离较远,是较进化的种类;棉铃虫齿唇姬蜂与弹尾目昆虫的遗传距离较近,是较早分化的种类.29种寄生蜂系统进化分析表明,茧蜂科的蚜茧蜂亚科和长体茧蜂亚科处于同一分化地位,但有明显分化;小蜂总科与姬蜂科处于同一分化地位,比茧蜂科分化晚.