有鳞目动物显微皮纹学

简要介绍了近年来国内外对有鳞目动物表皮扫描电镜研究的动态。现已描述了多样化的鳞片感觉器官;明确了有鳞目动物表皮具有复杂的组织学层次结构;其中最重要的是证明了表皮几丁质双层排列的事实以及得杂的蜕皮循环。研究还表明由于鳞片表皮结构特征在高级分类阶元中具有保守性,因而可以提供有用的系统演化信息。至少某些表皮特征,如微饰类型反映了系统联系而非生态适应。     

苔藓动物的起源与系统发生研究进展—形态学和分子生物学的证据

苔藓动物是后生动物中的一个重要类群。然而,和其它主要后生动物类群相比,长期以来对它的系统学研究却相对滞后。其起源,系统发生地位以及与其它后生物门类之间、其内部各高级分类群间的谱系发生关系一直存在争议。一般认为它是介于原口动物和后口动物之间的过渡类群。但是,近年来的分子系统学研究已经证实了它的原口归属。古生物学资料表明,虽然苔藓动物的大多数类群在奥陶纪已经分化出来,但它在寒武纪却缺乏任何化石记录。另外,苔藓动物起源的时间和方式、其内部各类群间的系统发生关系特别是现生类群和化石类群之间的关系等诸多问题的解决,还有待于大量的形态学和不同的分子数据的进一步积累,并结合其地层分布等各种相关资料进行综合研究。     

有鳞目动物显微皮纹学研究样品制备方法

有鳞目动物具有复杂的蜕皮循环,表皮层还具有复杂的组织学层次,然而只有最外面的角皮层有稳定的微细结构.在扫描电镜样品的制备过程中,常因不能区别蜕皮循环阶段造成混淆组织层次而影响研究成果的准确性.本文介绍的整体切割样品制备技术可以估计蜕皮循环阶段而无需依赖组织学技术,还介绍了一种简单的光学显微镜下皮纹学装片制作方法.     

有鳞目动物鳞片表面超微结构的适应性进化

爬行动物鳞片的微结构是对环境的一种适应。本研究运用扫描电子显微镜观察了北草蜥(Takydromus septentrionalis)、脆蛇蜥(Dopasia harti)和王锦蛇(Elaphe carinata)头部、背部和腹部鳞片的微皮纹结构及感受器特征。结果表明,3个物种的微皮纹和感受器存在种间差异。北草蜥和王锦蛇背部及腹部微皮纹均为狭长带状,脆蛇蜥为不规则多边形。北草蜥和王锦蛇颔片上有感受器,北草蜥无。脆蛇蜥腹部微皮纹上无小齿状凸起,北草蜥和王锦蛇有,与北草蜥相比王锦蛇的小齿状凸起更宽更长。王锦蛇的眼部微皮纹为向上竖起的脊,而其他部位的鳞片为具有小齿状凸起的狭长带状结构。本研究共收集整理17科99种的背鳞微皮纹数据和8科25种的感受器数据,对微皮纹特征和感受器形态进行祖先重建发现,狭长带状背鳞微皮纹主要存在于蜥蜴科(Lacertidae)、游蛇科(Colubridae)和石龙子科(Scincidae)中,而鬛蜥科(Agamidae)、蛇蜥科(Anguidae)、蟒蛇科(Boidae)以及蝰蛇科(Viperidae)的大多为多边形;较原始的感受器形态为无感觉毛的透镜状,这一结构在有...     

丝膜菌属分类系统和物种多样性研究进展

丝膜菌属是具有重要生态和经济价值的外生菌根真菌,其物种多样性丰富、形态复杂,因此物种的界定和分类研究较为困难。近年来,丝膜菌属的分类系统发生了重大的变化,且每年都有大量的新物种被描述。因此,准确理解该属的分类系统和物种多样性,对该类群分类研究的深入开展具有重要的指导意义。在大量文献调查的基础上,对丝膜菌属的分类系统及物种多样性研究现状进行了综述,探讨并展望了该类群今后的分类研究方向及需要重点解决的问题。     

山东半岛北部沿岸岛屿蝮属一新种(爬行纲,有鳞目,蝰科)

根据对山东半岛沿岸岛屿上的13号蝮蛇标本(7♂♂,6♀♀)外部形态的详细观察,并与同属其他各种比较,均有不同,应为亚洲蝮属1新种.新种的鉴别特征:1)中段背鳞23行;2)腹鳞+尾下鳞187～198,平均191行;3)体棕褐色,背部有两行粗大、周围暗棕色而中心色浅、外侧开放的圆斑,左右圆斑彼此交错或并列;4)眶后有一较宽黑色眉纹,其下缘略呈波状且镶有一条明显的白色细纹.     

跳甲亚科系统分类学研究进展

跳甲作为叶甲科Chrysomelidae中最大的一个类群具有重要的经济意义。该文简述了跳甲亚科Alticinae的分类研究历史 ,回顾了世界及中国的研究概况 ,从分类地位、族级阶元的划分、支序系统学及分子系统学等方面综述了跳甲亚科的最新研究进展 ,并简要讨论了存在的问题及研究前景     

SARS病毒研究进展

简要阐述了导致“非典”的病毒的形态学、分类学、病毒基因组、蛋白质组、病毒的检测和SARS病预防疫苗和诊断与治疗约物的研究进展。     

中国兽类分类与系统演化研究进展

中国兽类(即哺乳动物)种类繁多,对维持生态平衡发挥着重要的作用。自John R.Reeves于1829—1834年在我国广东开展兽类调查以来,近200年我国兽类分类及系统学研究取得了令世人瞩目的进步和发展。目前中国已知的兽类物种数已达686种,约占全世界兽类种数的10%,是世界上兽类物种多样性最丰富的国家之一。随着我国对生态环境保护的重视,生态环境日益改善,但全球气候变化、生境破碎化、人类活动增加及人兽共患重大疫情涌现等问题仍十分突出,兽类多样性调查及分类学研究的必要性越发明显。同时,兽类分类学这门古老而传统的学科也在不断引入各种新方法与技术,如整合分类学、标本数字化、模式标本测序、便携式测序技术及基于深度学习技术的物种识别鉴定等,分类学研究的成果及应用在近年得到了飞速发展。动物分类学作为传统的基础学科,是遗传学、生理学、生态学、医学、药学等现代生物学的基石。然而,由于学科特征和差异等原因,该学科近年来没有得到足够的重视,导致出现了学科萎缩和分类学人才后继无人的危机。因此,从国家层面对分类学、形态学等基础学科的人才培养、课题设置和资金投入等,予以特殊的政策支持,十分必要,也亟待解决。     

兰科植物系统学及亲缘关系研究进展

兰科植物是开花植物中最大的家族之一,现已受到全世界的重视。其种间或品种间的分类鉴定和亲缘关系的研究为育种工作提供了一个早期的、辅助的、选择性的指标。本文综述了近几年来兰科植物在比较形态学、细胞学、生物化学和分子生物学的研究进展。     

Exploring contradictory phylogenetic relationships in yeasts

Phylogenetic trees underlie our understanding of yeast evolution and are also proving instrumental in the development of a more robust yeast classification system based upon natural (i.e. evolutionary) relationships. In an effort to refine/improve taxonomic resolution, recent studies have focused on the use of multigene rather than single gene sequencing. Nevertheless, searches to determine 'the tree' remain problematic, as they can often overlook conflicts in the dataset. In such instances, phylogenetic networks such as neighbor-nets and consensus networks can provide a more useful and indeed more informative alternative means of analysis. In this study, we have used the latter two phylogenetic network techniques to reanalyze the multigene sequence dataset of Kurtzman & Robnett, which was used to redefine the taxonomy of the family Saccharomycetaceae. Results from our analyses show that, in general, established clades are robust. However, they also reveal conflict between mitochondrial- and nuclear-encoded genes and indicate the existence of complex patterns of hybridization and introgression not detected in the original study. These patterns are discussed in relation to how they may impact upon the current classification of this group of yeasts.     

A review of iguanian and anguimorph lizard genitalia (Squamata: Chamaeleonidae; Varanoidea, Shinisauridae, Xenosauridae, Anguidae) and their phylogenetic significance: comparisons with molecular data sets

We compare phylogenetic hypotheses for iguanian (chameleonids) and anguimorph lizard groups (varanoids, xenosauroids, anguids) which were generated from analyses of genital (hemipenial) morphology, with recent molecular phylogenetic approaches towards the same groups. Taxa with infraspecific communication by means of visible, sexually dimorphic epigamic characters usually have less diverse genital structures than taxa with less developed visible epigamic characters but with a more highly developed chemical intersexual communication. Generally, it turned out in the cases considered here, that phylogenetic hypotheses based on hemipenial characters coincide much better with molecular-genetic phylogenies than with earlier concepts based solely on external morphology. It seems that genital morphological characters are phylogenetically more informative – on both the species and the supraspecific level – than external morphological characters at least in these examples, because the former seem not to be affected by environmental selective pressures but seem to be only subject to sexual selection. Our data suggest that sexual selective pressure on genital structural diversity is higher the less sexually dimorphic, optical cues for infraspecific communication have evolved. They further suggest a correlation with the mating system (single versus multiple matings).     

The phylogenetic relationships of the physaloid genera (Solanaceae) based on morphological data

A group of genera, e.g., Chamaesaracha, Leucophysalis, Physaliastrum, Margaranthus, and Withania, in the subfamily Solanoideae (Solanaceae) is centered around the genus Physalis and has been named the physaloid group. It comprises a number of small and often poorly known genera, sometimes seen as united with Physalis and/or each other. A hypothesis of the phylogenetic relationships within this group, based on parsimony analyses of morphological data, is here presented for the first time. The result is discussed in relation to prevailing generic circumsciptions and taxonomic consequences. It is also compared with hypotheses of relationships based on cpDNA data.     

Comparative histology of the vaginal–cloacal region in Squamata and its phylogenetic implications

We described the histology and morphology of the vaginal–cloacal region in 18 species from 12 Squamata families. This comparative study revealed a wide variation in the cloacal morphology. Fifteen morphological characters were considered to be primary homology hypotheses and were optimized over the topology derived from the parsimony analysis of the available soft morphological evidence, including the characters described in this study. The synapomorphies optimized for Squamata are bifid urodaeum, common urodaeal cavity with similar histological features of the urodaeal horns, and presence of glands in the anterior urodaeum; for Scleroglossa the synapomorphy is the lateral position of the vaginal intrusion into the anterior urodaeal chamber, for Nyctisaura + Scincomorpha the synapomorphy is the presence of a bifid posterior urodaeum; and for Xantusidae + Annulata it is the presence of simple glands in the anterior urodaeum. The central position of the vaginal intrusion into the urodaeal chamber and the intraepithelial position of the glandular unit in the anterior urodaeum behave as autapomorphies for Iguanidae. This study contributes evidence that defines the relationships within Scleroglossa. Cloacal features provide interesting information that is useful as a source of morphological characters for phylogenetic studies in Squamata.     

Supermatrix data highlight the phylogenetic relationships of photosynthetic stramenopiles

Molecular data had consistently recovered monophyletic classes for the heterokont algae, however, the relationships among the classes had remained only partially resolved. Furthermore, earlier studies did not include representatives from all taxonomic classes. We used a five-gene (nuclear encoded SSU rRNA; plastid encoded rbcL, psaA, psbA, psbC) analysis with a subset of 89 taxa representing all 16 heterokont classes to infer a phylogenetic tree. There were three major clades. The Aurearenophyceae, Chrysomerophyceae, Phaeophyceae, Phaeothamniophyceae, Raphidophyceae, Schizocladiophyceae and Xanthophyceae formed the SI clade. The Chrysophyceae, Eustigmatophyceae, Pinguiophyceae, Synchromophyceae and Synurophyceae formed the SII clade. The Bacillariophyceae, Bolidophyceae, Dictyochophyceae and Pelagophyceae formed the SIII clade. These three clades were also found in a ten-gene analysis. The approximately unbiased test rejected alternative hypotheses that forced each class into either of the other two clades. Morphological and biochemical data were not available for all 89 taxa, however, existing data were consistent with the molecular phylogenetic tree, especially for the SIII clade.     

A multidisciplinary approach to the fine-systematics within Tisbe - an evaluation of morphological and molecular methods

Six species from the species-rich taxon Tisbe (Copepoda, Harpacticoida) were selected that could be reared in the laboratory as mass cultures. Phylogenetic relationships among these species were assessed by morphological studies of adults and larvae, DNA restriction site polymorphisms, allozymic, immunological distance, and lipid composition. Limits of scope and practicability of these analyses became apparent, as well as their potential and importance for future work in zoological systematics.     

昆虫γ-氨基丁酸受体研究现状

γ-氨基丁酸(gamma-aminobutyric acid,GABA)是脊椎动物和无脊椎动物体内重要的抑制性神经递质,其作用是引起神经传递的抑制,造成突触后膜的超极化,因而抑制动作电位的产生。占领GABA受体或破坏GABA受体的作用即能影响动物(昆虫)正常的突触传递,造成神经功能失常,从而引起死亡。基于此开发的杀虫剂主要有环戊二烯类,阿维菌素类等。近年GABA受体基因及其表达的研究,已为不同的种属GABA受体的亚基组成、生理功能及其对很多杀虫剂药物反应的多样性提供了令人信服的依据。     

Examining the utility of categorical models and alleviating artifacts in phylogenetic reconstruction of the Squamata (Reptilia)

Reconstruction artifacts are a serious hindrance to the elucidation of phylogenetic relationships and a number of methods have been devised to alleviate them. Previous studies have demonstrated a striking disparity in the evolutionary rates of the mitochondrial (mt) genomes of squamate reptiles (lizards, worm lizards and snakes) and the reconstruction artifacts that may arise from this. Here, to examine basal squamate relationships, we have added the mt genome of the blind skink Dibamus novaeguineae to the mitogenomic dataset and applied different models for resolving the squamate tree. Categorical models were found to be less susceptible to artifacts than were the commonly used noncategorical phylogenetic models GTR and mtREV. The application of different treatments to the data showed that the removal of the fastest evolving sites in snakes improved phylogenetic signal in the dataset. Basal divergences remained, nevertheless, poorly resolved. The proportion of both fast-evolving and conserved sites in the squamate mt genomes relative to sites with intermediate rates of evolution suggests rapid early divergences among squamate taxa and at least partly explains the short internal relative to external branches in the squamate tree. Thus, mt and nuclear trees may never reach full agreement because of the short branches characterizing these divergences.     

植物根系形态对低磷胁迫应答的研究进展

本文综述了近年来植物对磷营养高效吸收有关的根系形态方面的研究进展,总结了植物适应低磷胁迫的根系形态特征,以及植物适应低磷胁迫根系形态变化的激素调控的内在机制,着重阐述了植物适应低磷根系形态变化的分子生物学基础,并对开展此类工作的有效途径进行了探讨.