我国沿海拟菱形藻属的2新记录种及其产毒特征分析

为澄清我国沿海拟菱形藻属(Pseudo-nitzschia)的物种多样性,并确认中国海域拟菱形藻属是否具有产生多莫酸(Domoicacid)的能力,采用毛细管显微操作技术从我国沿海水体中分离、纯化拟菱形藻细胞,建立了单克隆培养株系,并基于核糖体转录间隔区ITS1-5.8S-ITS2 序列构建了分子系统树。结果表明,结合在光学显微镜和透射电镜下观察的形态学特征和分子系统发育分析数据,鉴定到我国拟菱形藻属的2新记录种:银河拟菱形藻(P. galaxiae Lundholm & Moestrup)和微孔拟菱形藻(P. micropora Priisholm, Moestrup & Lundholm),对其形态学特征进行了详细描述,并与相似种类进行了比较研究。利用高效液相色谱(HPLC)技术对多莫酸特征进行了检测,结果表明培养株系并不产生多莫酸。这些为我国拟菱形藻属物种多样性和产毒特征研究提供了基础数据。     

中国沿海新报道的三种产毒拟菱形藻

为了明确我国海域拟菱形藻属(Pseudo-nitzschia)物种的产毒特征, 从中国沿海建立了15个拟菱形藻单克隆培养株系, 利用高效液相色谱-质谱联用法对其多莫酸特征进行检测, 在10个株系中检测到多莫酸。结合光学显微镜下的群体特征和透射电镜下的超微形态学特征, 以及基于核糖体转录间隔区的分子系统学数据, 确认上述10个产毒株系分别隶属于3个物种:尖细拟菱形藻P. cuspidata、伪柔弱拟菱形藻P. pseudodelicatissima、伪善拟菱形藻P. fraudulenta, 其中伪善拟菱形藻是我国的新记录种。建立尖细拟菱形藻的11个尖细拟菱形藻株系, 其中3个株系未检出多莫酸, 其余8个株系有检出, 单细胞产毒水平为0.4—5.5 fg。建立伪柔弱拟菱形藻株系2个, 1个未检出多莫酸, 另1个株系的单细胞产毒量为1 fg。建立伪善拟菱形藻株系2个, 纯种培养株系均未检出多莫酸。利用卤虫(Artemia salina)对部分藻株进行混培诱导, 其中尖细拟菱形藻(MC4049)和伪柔弱拟菱形藻(MC3015)的产毒水平略有下降, 单细胞产毒水平分别由2、1 fg降至0.2、0.4 fg, 而伪善拟菱形藻(MC4074)的产毒能力则有显著改变, 单细胞产毒水平由未检出上升至17.5 fg。研究丰富了我国产毒拟菱形藻的物种多样性, 明确了其物种信息和产毒水平, 可为后续深入研究提供基础数据。     

大亚湾水域并基拟菱形藻的种类鉴定和产毒特征分析

为了丰富我国海域拟菱形藻(Pseudo-nitzschia Peragallo)的物种多样性, 并澄清其产毒特征, 研究从广东大亚湾海域分离并建立了一株拟菱形藻的单克隆培养株系MC298, 通过光学显微镜下的群体特征和透射电镜下的超微形态特征观察, 结合基于核糖体转录间隔区(Internal Transcribed Spacer, ITS)的分子系统学数据, 以及基于ITS2转录RNA的二级结构分析, 鉴定到我国拟菱形藻属的1个新记录种: 并基拟菱形藻P. decipiens Lundholm & Moestrup。研究对其形态学特征进行了较为详细地描述, 并与相似种进行了比较, 还对其ITS2-RNA的特有标志结构进行了阐述。同时, 利用高效液相色谱-质谱联用法(Liquid chromatography tandem mass spectrometry, LC-MS/MS)对该藻株的产毒特征进行了检测, 结果未检测到DA的存在。研究不仅丰富了我国拟菱形藻属的物种多样性, 也可为拟菱形藻的产毒特征研究提供基础数据。     

我国沿海线形亚属海链藻的形态学研究

壳面孔纹的形态学特征是海链藻的重要分类学依据之一。线形亚属的海链藻种类大多是从圆筛藻属修订而来, 它们之间的区别特征细微, 需电镜下观察才能准确鉴定。我国关于线形亚属海链藻的报道较少。研究利用电镜(EM)技术, 对采自我国沿海海域的自然水样, 以及分离获得的单克隆培养藻株进行了形态学观察, 针对其中的海链藻属Thalassiosira Cleve种类开展了形态分类学的专题研究。报道了6个隶属于线形亚属的海链藻种类, 分别是紧密海链藻T. densannula Hasle &; Fryxell、微小海链藻T. exigua Fryxell &; Hasle、线形海链藻T. lineata Jousé、微线形海链藻T. nanolineata (Mann) Fryxell &; Hasle、结线形海链藻T. nodulolineata (Hendey) Hasle &; Fryxell和柔弱海链藻T. tenera Proschkina-Lavrenko, 其中有4个为我国新记录种类: 紧密海链藻、线形海链藻、微线形海链藻和结线形海链藻。对每个种类的形态学特征、生活习性和生态分布进行了描述, 提供了电镜照片。对相似种类的形态学特征进行了比较研究, 分析了孔纹特征的变化类型及其分类学意义。     

新疆菱形藻属和细齿藻属(硅藻门)中国新记录植物

2001年7月至8月、2007年7月分别两次在新疆各地采集硅藻标本,经显微观察,共鉴定出菱形藻属和细齿藻属(硅藻门)中国新记录植物11种1变种,其中菱形藻属9种:额雷菱形藻(Nitzschia eglei Lange-Bertalot)、弯曲菱形藻(N.flexa Schumann)、多样菱形藻(N.diversa Hustedt)、化石菱形藻[N.fossilis (Grunow) Grunow]、吉斯纳菱形藻(N.gessneri Hustedt)、平庸菱形藻(N.inconspicua Grunow)、辐射菱形藻(N.radicula Hustedt)、常见菱形藻(N.solita Hustedt)和粗肋菱形藻(N.valdecostata Lange-Bertalot & Simonsen);细齿藻属2种1变种:科瑞提细齿藻[Denticula creticola (strup) Lange-Bertalot & Krammer]、库津细齿藻汝牧变种(D.kuetzingii var.rumrichae Krammer)和强壮细齿藻[D.valida (Pedicino) Grunow].并对其12种新记录植物的分类学特征进行了详细的描述.     

镰刀藻属与伪镰刀藻属的超微结构比较研究

利用扫描电镜对华南沿海及澳大利亚分布的镰刀藻属（Falcula）和伪镰刀藻属（Pseudofalcula）硅藻进行了形态学观察。发现一中国新记录硅藻,即中间镰刀藻（F. media Voigt）;首次报道了半波镰刀藻（F.semiundulata Voigt）的超微形态结构;通过与透明伪镰刀藻（P. hyalina (Takano) Gómez, Wang&Lin）的比较进一步界定了两属的形态学差异。其中,二者顶纹区结构的差异最为显著：镰刀藻属的顶纹区由数条狭缝组成,而伪镰刀藻属的顶纹区为嵌入壳套的眼点且呈网格状结构。此外,明确了镰刀藻属物种多是大型海藻上的植表生硅藻,而伪镰刀藻属则为典型的动表生硅藻,其宿主为海洋桡足类。本文扩大了中间镰刀藻、半波镰刀藻和透明伪镰刀藻的地理分布区域,厘清了镰刀藻属和伪镰刀藻属的形态学划分依据。     

大亚湾美洲拟菱形藻复合群的形态学观察

拟菱形藻(Pseudo-nitzschia)是一类常见的海洋微藻,它属于硅藻门,羽纹纲,管壳缝目,菱形藻科.本属种类可以广泛分布在两极、温带、亚热带和热带海域.     

大亚湾大鹏澳水域春季浮游植物优势种的演替

根据2002年4月28日～5月27日大亚湾大鹏澳内每日采样的现场连续观测资料,使用主分量分析方法和多元回归方法,分析浮游植物优势种类之间的关系及影响其生长与演替的主要理化因子,建立春季浮游植物优势种类的演替模型。模型表明,中肋骨条藻和柔弱菱形藻之间为竞争关系;与浮游植物(以硅藻为主)生长密切相关的理化因子为温度(T)、溶解氧饱和度(DOsat)、铵氮(NH4-N)、亚硝酸氮(NO2-N)、磷酸盐(PO4-P)、硅酸盐(SiO3-Si)。影响中肋骨条藻的理化因子还有盐度(S)和氮磷比值(NO3／PO4)。并根据优势种类发生演替期间的环境变化(降雨),分析了浮游植物优势种由中肋骨条藻演替为柔弱菱形藻的过程。     

东海低氧区及邻近水域浮游植物的季节变化

根据2011年5月、8月、11月在东海低氧区及邻近水域(25°00'—33°30'N,120°00'—127°30'E)进行的多学科综合调查,对东海低氧区及邻近水域浮游植物群落结构特征及季节变化进行了相关研究。经Utermhl方法初步分析共鉴定出浮游植物4门74属248种(含变种、变型,不含未定种),主要由硅藻和甲藻组成,此外还有少量的金藻和蓝藻。春季优势种主要为具齿原甲藻(Prorocentrum dentatum)、柔弱伪菱形藻(Pseudo-nitzschia delicatissim)、骨条藻(Skeletonema sp.)和具槽帕拉藻(Paralia sulcata);夏季主要是中肋骨条藻(Skeletonema costatum)和海链藻(Thalassiosira sp.);秋季主要是具槽帕拉藻、圆筛藻(Coscinodiscus sp.)和柔弱伪菱形藻。调查区浮游植物平均细胞丰度在夏季最高,达到85.002×103个/L,春季次之,秋季最低。在水平方向上,春、夏两季,表层浮游植物细胞丰度在近岸出现高值,由近岸到外海细胞丰度逐渐降低;而在秋季则相反,在调查海域的东北部出现高值,随离岸距离的增加细胞丰度逐渐增加。在垂直方向上,春、夏两季,浮游植物细胞丰度在表层出现最大值,随着深度的增加细胞丰度逐渐降低;而在秋季细胞丰度分布比较均匀,随水深变化不明显。调查区表层浮游植物ShannonWiener多样性指数和Pielou均匀度指数的平面分布基本一致,并且与细胞丰度的分布大致呈镶嵌分布。调查浮游植物群落的演替规律是:从春季的甲藻(具齿原甲藻、微小原甲藻(Prorocentrum minimum)等)为主,硅藻(柔弱伪菱形藻、骨条藻等)为辅;演替至夏季的硅藻(中肋骨条藻、海链藻等)为主,甲藻(主要是梭状角藻(Ceratium fusus)和叉状角藻(Ceratium furca))为辅,到秋季进一步演替为硅藻(具槽帕拉藻、圆筛藻、柔弱伪菱形藻等)为主,铁氏束毛藻(Trichodesmium thiebaultii)为辅。浮游植物物种组成、优势种、细胞丰度及多样性指数均表现出明显的时空变化。低氧区与非低氧区浮游植物群集存在明显差异。     

我国沿海闭合突海链藻的形态学研究

闭合突是一类特殊的突起, 仅报道于少数海链藻种类, 其形态学特征和排列方式是重要的分类学依据。我国关于闭合突海链藻的报道较少。研究利用扫描电镜(SEM)技术, 对采自我国沿海海域的自然水样, 以及分离获得的单克隆培养藻株进行了形态学观察, 针对其中的海链藻属Thalassiosira Cleve种类开展了形态分类学的专题研究。报道了5个具有闭合突的海链藻种类, 分别是西达礁海链藻T. cedarkeyensis Prasad、偏心海链藻T. eccentrica (Ehrenberg) Cleve、伦德海链藻T. lundiana Fryxell、细孔海链藻T. punctigera (Castracane) Hasle和管状海链藻T. tubifera Fryxell, 其中有3个为我国新记录种类: 西达礁海链藻、细孔海链藻和管状海链藻。对每个种类的形态学特征和生境进行了描述, 提供了扫描电镜照片, 对相似种类的形态学特征进行了比较研究, 分析了突起特征的变化类型及其分类学价值。       

Regulation of seasonal reproduction in mollusks

Understanding the physiological basis of environmental regulation of reproduction at the cellular level has been difficult or unfeasible in vertebrate species because of the highly complex and diffuse nature of vertebrate neuroendocrine systems. This is not the case with the simple nervous system of mollusks in which reproductive neuroendocrine cells are often readily identifiable in living tissue. Given that there are mollusks that are seasonal breeders, that the neuroendocrine cells controlling reproduction have been identified in several molluskan species, that these neurons are conducive to cell physiological analysis, and that basic features of cell biology have been highly conserved between mammals and mollusks, it seems that the mollusk would provide an excellent model system to investigate cell-physiological events that mediate effects of environmental signals on reproduction. The purpose of this review is to explore this idea in three species in which the topic of the neural basis of seasonal reproduction has been studied: the giant garden slug Limax maximus, the freshwater pond snail Lymnaea stagnalis, and the marine snail Aplysia californica.     

Selection for improved yield in inter-specific mixtures or intercrops

Summary A simple recurrent selection scheme using randomly constructed intercrop or mixture treatments for the mutual improvement of two or more species is described. Several possible selection criteria are available for each species, including its own yield, those of each of its associates, and combinations of these. Statistical expressions are developed to describe the expected gain in economic yield in each species given selection for one or more species on the basis of any common criterion, and it is shown that the gains from all responding species and applied selection criteria are additive. Negative correlations between the direct and associate effects of genotypes favour the selection of whole mixtures. Selection indices of several species yields can be applied either on an individual species basis or to whole mixtures, but only in the latter case can the statistics required for the calculation of the optimum index be estimated from the data provided by the trial. Some general properties and possible long term effects of different selection methods are discussed.     

Conservation biogeography of large Mediterranean islands. Butterfly impoverishment, conservation priorities and inferences for an ecologica "island paradigm"

Conservation biogeography is considered the Cinderella of biological conservation. Nevertheless biogeography provides the basis for establishing species distributions over space and time, therefore conservation priorities among areas and individual species. We demonstrate that there is no need to simplify analyses by using subsets of species (rare species, endemics) as surrogates. In doing so, we apply strict biogeographical techniques to determine butterfly impoverishment on three of the west Mediterranean's largest islands (Sardinia, Corsica and Sicily). The analyses performed on species, both collectively and individually, reveal that regional species richness in the Mediterranean zone can be largely predicted by latitude, altitude and latitudinal range (maximum minus minimum latitude), but that Sardinia and Corsica have clearly impoverished faunas. Logistic regression at individual species level demonstrates that several species, predicted to be present in these islands on the basis of their continental distributions, are actually absent. When compared with species that are present in these islands, such missing species are disclosed as having ecological traits which reduce their colonization capability. Probabilities of occurrence are calculated for each species on each island; they reflect the potential for each butterfly species to migrate to and colonise each island, and can be considered as a measure of conservation value. As such, species present on islands but having low immigration probabilities are predicted to represent isolated populations from the mainland that are unlikely to re-colonize the islands in the case of extinction. Island endemic species and races are shown to have lower occurrence probabilities compared to widespread species occurring on islands and illustrate the usefulness of occurrence probabilities for identifying isolated populations in need of conservation attention.     

The use of bacterial spore formers as probiotics

The field of probiosis has emerged as a new science with applications in farming and aqaculture as alternatives to antibiotics as well as prophylactics in humans. Probiotics are being developed commercially for both human use, primarily as novel foods or dietary supplements, and in animal feeds for the prevention of gastrointestinal infections, with extensive use in the poultry and aquaculture industries. The impending ban of antibiotics in animal feed, the current concern over the spread of antibiotic resistance genes, the failure to identify new antibiotics and the inherent problems with developing new vaccines make a compelling case for developing alternative prophylactics. Among the large number of probiotic products in use today are bacterial spore formers, mostly of the genus Bacillus. Used primarily in their spore form, these products have been shown to prevent gastrointestinal disorders and the diversity of species used and their applications are astonishing. Understanding the nature of this probiotic effect is complicated, not only because of the complexities of understanding the microbial interactions that occur within the gastrointestinal tract (GIT), but also because Bacillus species are considered allochthonous microorganisms. This review summarizes the commercial applications of Bacillus probiotics. A case will be made that many Bacillus species should not be considered allochthonous microorganisms but, instead, ones that have a bimodal life cycle of growth and sporulation in the environment as well as within the GIT. Specific mechanisms for how Bacillus species can inhibit gastrointestinal infections will be covered, including immunomodulation and the synthesis of antimicrobials. Finally, the safety and licensing issues that affect the use of Bacillus species for commercial development will be summarized, together with evidence showing the growing need to evaluate the safety of individual Bacillus strains as well as species on a case by case by basis.     

STRUCTURALLY PRESERVED PLANTS FROM SOUTHEASTERN KENTUCKY: STAUROPTERIS BISERIATA SP. NOV.

Several axes of the coenopterid fern Stauropteris are described from permineralized peat associated with Lower-Middle Pennsylvanian coal deposits of southeastern Kentucky. This represents the first documented report of the genus in North America. The specimens are regarded as representatives of a new species—S. biseriata—based on the distinctive branching habit. Three branch orders are described, and in each case, branches are singular and distichous, arranged in a two-ranked pattern. This is in contrast to other species of Stauropteris in which the branches are paired and form a quadriseriate pattern. A pair of vascularized aphlebiae subtend each branch through all branching orders. Aphlebiae associated with first- and second-order branches are three-parted at the point of insertion; those that subtend third-order branches are singular. Stauropteris and a number of Devonian fern-like plants are compared on the basis of certain morphological similarities.     

Cost effectiveness of endangered species management: the kokako (

Expenditure on endangered species management is increasing greatly, on a global basis. Managers need tools to evaluate the performance of endangered species programmes because there will always be more demand for resources than there are available. Cost Effectiveness Analysis (CEA) is used here to evaluate the performance of the kokako (Callaeas cinerea) recovery programme. This species is being managed at a number of sites in New Zealand and analysis shows a large variation in costs and effectiveness between these sites. Cost Effectiveness Analysis provides a tool to allow managers to better predict where resources should be invested to most cost-effectively achieve their conservation targets, in this case recovery of an endangered species. Issues of lack of reliable cost data and ongoing policy problems limit the potential of economics to contribute to improved conservation management of threatened species in New Zealand.     

The Biosemiotic Concept of the Species

Any biological species of biparental organisms necessarily includes, and is fundamentally dependent on, sign processes between individuals. In this case, the natural category of the species is based on family resemblances (in the Wittgensteinian sense), which is why a species is not a natural kind. We describe the mechanism that generates the family resemblance. An individual recognition window and biparental reproduction almost suffice as conditions to produce species naturally. This is due to assortativity of mating which is not based on certain individual traits, but on the difference between individuals. The biosemiotic model described here explains what holds a species together. It also implies that boundaries of a species are fundamentally fuzzy, and that character displacement occurs in case of sympatry. Speciation is a special case of discretisation that is an inevitable result of any communication system in work. The biosemiotic mechanism provides the conditions and communicative restrictions for the origin and persistence of diversity in the realm of living (communicative and semiotic) systems.     

Secrets of the subterranean pathosystem of Armillaria

Armillaria root disease affects fruit and nut crops, timber trees and ornamentals in boreal, temperate and tropical regions of the world. The causal pathogens are members of the genus Armillaria (Basidiomycota, Physalacriaceae). This review summarizes the state of knowledge and highlights recent advances in Armillaria research. Taxonomy: Armillaria includes more than 40 morphological species. However, the identification and delineation of species on the basis of morphological characters are problematic, resulting in many species being undetected. Implementation of the biological species' concept and DNA sequence comparisons in the contemporary taxonomy of Armillaria have led to the discovery of a number of new species that are not linked to described morphological species. Host range: Armillaria exhibits a range of symbioses with both plants and fungi. As plant pathogens, Armillaria species have broad host ranges, infecting mostly woody species. Armillaria can also colonize orchids Galeola and Gastrodia but, in this case, the fungus is the host and the plant is the parasite. Similar to its contrasting relationships with plants, Armillaria acts as either host or parasite in its interactions with other fungi. Disease control: Recent research on post-infection controls has revealed promising alternatives to the former pre-plant eradication attempts with soil fumigants, which are now being regulated more heavily or banned outright because of their negative effects on the environment. New study tools for genetic manipulation of the pathogen and characterization of the molecular basis of the host response will greatly advance the development of resistant rootstocks in a new stage of research. The depth of the research, regardless of whether traditional or genomic approaches are used, will depend on a clear understanding of where the different propagules of Armillaria attack a root system, which of the pathogen's diverse biolymer-degrading enzymes and secondary metabolites facilitate infection, and how the course of infection differs between resistant and susceptible hosts.     

Quantifying effects of legal and non-legal designations of alien plant species on their control and profile

Invasive alien species (IAS) pose serious threats to native ecosystems worldwide. In some regions, laws and/or lists related to alien species have been made, but their effects on actual measures against alien species have been little studied. In Japan the IAS act, which came into force in 2005, lists many harmful species under the heading “Designated IAS”. The importation, domestication, sale or release of these species is tightly regulated. In addition, other species are named as alerted alien species (AASs) on the “alien species alert list” to raise public awareness. In this paper we examined the situation in Japan as case study that is exposed to threats from alien species under such laws in recent year to evaluate the effects of that for public interesting. We conducted a survey of the effects of the legal designation and other classification of alien plant species, examining a number of aspects, including research publications, eradications and public awareness. In our analysis, the degree of harmfulness of IASs was considered on the basis of weed risk assessment (WRA). The results show that legal classification of IASs has led to increases in research focused on the designated species, eradication efforts and public awareness. Similar results were also apparent for some AASs, but there was a great deal of variability among the many sub-categories of AASs. This may be partly because AAS sub-categories are based on different premises, and partly because the identification of AASs is not necessarily linked to legal controls that affect the behavior of individuals.     

Using directed phylogenetic networks to retrace species dispersal history

Methods designed for inferring phylogenetic trees have been widely applied to reconstruct biogeographic history. Because traditional phylogenetic methods used in biogeographic reconstruction are based on trees rather than networks, they follow the strict assumption in which dispersal among geographical units have occurred on the basis of single dispersal routes across regions and are, therefore, incapable of modelling multiple alternative dispersal scenarios. The goal of this study is to describe a new method that allows for retracing species dispersal by means of directed phylogenetic networks obtained using a horizontal gene transfer (HGT) detection method as well as to draw parallels between the processes of HGT and biogeographic reconstruction. In our case study, we reconstructed the biogeographic history of the postglacial dispersal of freshwater fishes in the Ontario province of Canada. This case study demonstrated the utility and robustness of the new method, indicating that the most important events were south-to-north dispersal patterns, as one would expect, with secondary faunal interchange among regions. Finally, we showed how our method can be used to explore additional questions regarding the commonalities in dispersal history patterns and phylogenetic similarities among species.