DNA的化学合成及其应用

通过二十多年的探索和研究,脱氧核糖寡核苷酸(DNA)片段的化学合成得到了突飞猛进的发展。DNA固相合成技术的问世更使DNA化学合成技术达到了精确、高效和自动化。重组DNA技术以及外源DNA分子在异源体系中的表达为DNA结构功能及基因表达调控机制的研究打开了新局面,使得生物学的研究发生了革命性的变化,而DNA分子的化学合成为分子生物学家对特定的基因进行遗传工程的操作,选择性地对DNA分子进行改造提供了崭新的手段。借助于化学合成的DNA片段,人     

植物组织培养生产有用化合物的潜力与问题

高等植物仍然是许多有用化合物的重要来源药物、调味品和香料等有用化合物在近半个世纪以来有用化学合成的趋向。但还存在下述的状况:1.化学合成有困难;2.还不能人工组成某些复杂的混合物,例如玫瑰     

环氧化物的生物不对称合成

手性环氧化物是有机化学合成中重要的中间体;与以往化学合成方法相比,手性环氧化物的生物合成有其独特之优点;本文从直接加氧、间接环氧和酶解拆分三个途径全面地介绍该领域的研究成果和最新进展,并对其未来的发展和方向进行了展望 。     

糖基化学品的生物制造

正目前,糖基化学品的合成主要通过提取法、化学合成法来生产,然而这些合成法存在严重的弊端。化学合成法会带来严重的环境污染且生物活性低;提取法收率较低,原料有限。代谢工程作为一种重要糖基化学品合成工具,已经成为替代原有化学合成方法的有效策略。综述了N-乙酰氨基葡萄糖、木糖醇、海藻糖、甘草酸等几种应用广泛的精细糖基化学品的生物制造与应用,并讨论了生物制造糖基化学品的前景和挑战。     

生物法合成乙醛酸

乙醛酸是一种重要的有机化工中间体 ,化学性质活泼 ,应用领域广泛 ,因而它的合成倍受关注。乙醛酸的合成分为化学合成法和生物合成法 ,现在工业生产基本上都是化学法。而生物合成法以其显著的优点成为近年来的研究热点。在综述生物法合成乙醛酸的基础上比较了生物合成法和化学合成法的优缺点。     

环氧化物的生物不对称合成

手性环氧化物是有机化学合成中重要的中间体,与以往化学合成方法相比,手性环氧化物的生物合成有其独特之优点,本文从直接加氧、间接环氧和酶解拆分三个途径全面地介绍该领域的研究成果和最新进展,并对其未来的发展和方向进行了展望。     

生物表面活性剂及其应用

生物表面活性剂是由微生物产生的一类具有表面活性的生物化合物,除具有化学合成表面活性剂的理化特性外,还具有无毒、能生物降解等优点,其应用前景非常广阔,并有可能成为化学合成表面活性剂的替代品或升级换代品。简述了生物表面活性剂的历史、特性、种类及应用研究进展 。     

生物表面活性剂及其应用

生物表面活性剂主要是由微生物产生的一种生物在分子物质,具有或优于化学合成表面活性剂的理化特性,作为一种绿色天然产物。极有可能取代化学合成表面活性剂,其应用前景十分广阔。本文阔述了生物表面活性剂的特点,种类,着重介绍它的潜在应用。     

恶性疟原虫杂合多肽抗原与霍乱毒素B亚单位融合基因在大肠杆菌中的表达

目前疟疾因其发病率较高,分布范围广,恶性疟病程凶险和无特效疫苗用于预防而倍受关注,研制有效的疫苗刻不容缓。由于用常规方法难以研制抗疟疫苗,不少实验室都在尝试用多肽化学合成和基因重组等生物高技术来解决这一世界性难题。我们在patarroyo报道的化学合成的45肽和58肽这两种杂     

各种RNA干扰库的构建及比较

不同种类的RNA干扰库已经被用于基因功能的研究之中,根据其构建方式和分子形式的不同,可将RNA干扰库分为4种类型,即化学合成的小干扰RNA（siRNA）库、化学合成的小发夹RNA（shRNA）表达库、酶切法构建的siRNA库和酶切法构建的shRNA表达库。简要介绍上述RNA干扰库的构建方法及其特点和局限。     

Phylogenetic definitions and taxonomic philosophy

An examination of the post-Darwinian history of biological taxonomy reveals an implicit assumption that the definitions of taxon names consist of lists of organismal traits. That assumption represents a failure to grant the concept of evolution a central role in taxonomy, and it causes conflicts between traditional methods of defining taxon names and evolutionary concepts of taxa. Phylogenetic definitions of taxon names (de Queiroz and Gauthier 1990) grant the concept of common ancestry a central role in the definitions of taxon names and thus constitute an important step in the development of phylogenetic taxonomy. By treating phylogenetic relationships rather than organismal traits as necessary and sufficient properties, phylogenetic definitions remove conflicts between the definitions of taxon names and evolutionary concepts of taxa. The general method of definition represented by phylogenetic definitions of clade names can be applied to the names of other kinds of composite wholes, including populations and biological species. That the names of individuals (composite wholes) can be defined in terms of necessary and sufficient properties provides the foundation for a synthesis of seemingly incompatible positions held by contemporary individualists and essentialists concerning the nature of taxa and the definitions of taxon names.     

Comparison of in vitro decomposition of bryophytic and tracheophytic plant material

The fossil record of bryophytes is generally poor and infertile plants attributable to liverworts and mosses could also be thalloid vascular plant gametophytes or herbaceous lycophytes respectively. The paucity of the bryophytic record could be the result of relatively rapid degradation of bryophytic material in comparison to that of vascular plants, the absence of lignified cells in bryophytes sustaining this belief. However, certain organs of bryophytes are as robust as those of vascular plants (e.g. spores) and the hydroxybenzofuran polymers produced by some mosses could be of similar preservational resistance to lignins. A simplistic experiment to test the relative resistance to decay of bryophytic material has been undertaken. Its findings suggest that bryophytic plant material has a similar preservational potential to that of a selected vascular plant, particularly in organic rich sediments. This result may be construed to imply that bryophytes were indeed less abundant in the preservational environments of the Coal Measures than might be expected on the basis of current palaeoenvironmental reconstructions.     

Échinodermes de l'Ordovicien supérieur (Ashgill) de Sardaigne et d'Algérie

Research on the influence of sea level variations on the benthic faunas have been carried out in the Upper Ordovician of Sardinia. Study of the depositional facies and sequence analysis of the upper part (Lower Ashgill) of the Portixeddu Formation led to the identification of the sedimentary environments. Cystoids and crinoids are associated to bryozoans and brachiopods in most levels. The numerical analysis of associations and megaguilds shows that crinoids and cystoids have a higher frequency in the proximal and median facies of the upper offshore. The columnal association characterized by Conspectocrinus celticus and the coronoid Mespilocystites tregarvanicus has been discovered in the upper part of the formation. This material and complementary samples from Upper Ordovician of Sardinia and Kabylia (Algeria) bring additional data on the systematic and show the wide distribution of this fauna outside of the Ibero-armorican domain. The distribution of this echinoderm association supports a palaeogeographical position of the Ibero-armorican domain and Sardinia within the north gondwanan margin during the Lower Palaeozoic.     

Des Miliolacea aux Alveolinacea (grands foraminifères): la faune du Crétacé supérieur et du Tertiaire inférieur du Chiapas (S.E. Mexique)

Found in Chiapas (South-East of Mexico), Praealveolina michaudi nov. sp. and Chubbina jamaicensis (of Campanian-Maestrichtian age) are described, both evolved from Nummoloculina sp. while Raadshoovenia guatemalensis (upper Paleocene-lower Eocene) arises from Quinqueloculina. We precisely analyze and modelize the nepionic coiling during the evolutionary change from Miliolacea to Alveolinacea. During ontogenesis as well as during phylogenesis, quinqueloculine coiling progresses to streptospiral and then to planispiral chamber arrangement with the increase of volume of embryo and of chambers. Appearance of these large foraminifers are understood as a consequence of the rise of K-strategies in their mode of life, following the development of photosynthetic symbioses.     

人工合成多样性突变文库研究进展*

突变文库的构建是定向进化研究过程中一个关键步骤,主要利用天然存在的系统或者人工合成的分子技术来产生多样性核酸分子文库,为制备和筛选具有一定特性的蛋白酶、多肽、人工抗体等提供庞大的遗传基因库,也可用于合成生物学中相关基因元件的研究与筛选,为目标生物制品的高效工业化生产提供动力。随着对突变文库构建技术研究的日益深入,各种文库构建策略相继被开发出来,并在生物能源、生物化工、生物医药、生物试剂和食品工业等方面得到了广泛的应用。然而,定向进化中的文库构建策略多有不同,各种突变文库构建技术的核心方法也在不断创新。主要介绍近年来实验室中人工合成多样性文库的前沿技术,并对文库构建技术在自动化和智能化方向的发展进行了展望。     

A phylogenetic analysis of basal Anseriformes, the fossil Presbyornis, and the interordinal relationships of waterfowl

A phylogenetic analysis of 123 morphological characters of basal waterfowl (Aves: Anseriformes) and other selected avian orders confirmed that the screamers (Anhimae: Anhitn-idae) are the sister-group of other waterfowl (Anseres), and that the magpie goose (Anseranatidae: Anseranas semipalmata) is the sister group of other modern waterfowl exclusive of screamers (Anatidae sensu stricto). The analysis also supports the traditional hypothesis of the gallinaceous birds (Galliformes) as the sister group of the Anseriformes. Presbyornis, a fossil from the early Eocene of Wyoming and averred by Olson & Feduccia as showing that the Anseriformes were derived from shorebirds (Charadriiformes), was found to represent the sister group of the Anatidae. Associated hypotheses by Olson & Feduccia concerning the implications of Presbyornis for the phylogenetic relationships of flamingos (Phoenicopteriformes), the position of the Anhimidae within the waterfowl, relationships among modern Anatidae, and a plausible evolutionary scenario for waterfowl also are rejected. Analyses revealed that cranial characters were critical to the establishment of the Galliformes as the sister group of the Anseriformes; exclusion of the Anhimidae, especially in combination with Anseranas, also undermined the support for this inference. Placement of Presbyornis as the sister group of the Anatidae casts doubt on the role suggested by Feduccia of ‘transitional shorebirds' in the origin of modern avian orders, and calls into question the concept of ‘fossil mosaics’. The phylogenetic hypothesis is used to reconstruct an evolutionary scenario for selected ecomorphological characters in the galliform-anseriform transition, to predict the most parsimonious states of these characters for Presbyornis, and to propose a phylogenetic classification of the higher-order taxa of waterfowl. This re-examination of Presbyornis also is used to exemplify the fundamental methodological shortcomings of the intuitive approach to the reconstruction of phylogenetic relationships.     

L’habitat en grotte au Néolithique : vers une estimation de l’intensité des occupations

The archaeological excavation of the cave of the Gardon has brought to light a dilated and nearly continuous stratigraphy for the Neolithic era. The analysis of lithic industry has showed the existence of variations between those neolithic layers, which are independents of the technological processes of tools productions. Four criteria allow us to characterize the occupation’s type of each layer. Compared to the excavations data and to sedimentological analysis, these results allow us to display the evolution of the intensity of occupations of the cave throughout the whole Neolithic.     

The Natural Host Range of Steinernema and Heterorhabditis spp. and Their Impact on Insect Populations

The natural host range of entomopathogenic nematodes of the genera Steinernema and Heterorhabditis can be defined as the range of insects which indigenous nematode populations use for propagation. Information on the natural host range is rare. However, based on records of insects found to be naturally infected with nematodes, some conclusions regarding the natural host range of some Steinernema spp. and Heterorhabditis spp. are presented. Reports of indigenous nematode populations impacting on insect populations can be divided between relatively balanced, long-lasting nematode-host associations and unbalanced, short-lasting epizootics. Examples of the augmentation and inoculative introduction of nematodes in agriculture and forestry ecosystems are presented. Based on current knowledge, nematode reproduction strategies are discussed and indications of the risk involved in the release of non-indigenous nematodes are given.     

Concentration of 17 trace elements in serum and whole blood of plains viscachas (Lagostomus maximus) by ICP-MS, their reference ranges, and their relation to cataract

The reference ranges of the trace elements Al, As, Be, B, Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, Li, Rb, Se, Sr, and Zn were determined by inductively coupled plasma-mass spectrometry (ICP-MS) in sera of a group of free-ranging plains viscachas of the pampa grasslands of Argentina. The values were compared with those of a small group of captive plains viscachas of the Zurich Zoo with diabetes and bilateral cataracts. In addition, a method for digestion of whole-blood samples is described for the trace element determination. Significant differences in the concentration of trace elements in the two groups of animals are discussed. No correlation was found between the levels of selenium and of other trace elements compared to the formation of cataracts.     

A Species-specific Monoclonal Antibody System for Detecting the Remains of Field Slugs, Deroceras reticulatum (Muller) (Mollusca: Pulmonata), in Carabid Beetles (Coleoptera: Carabidae)

The field slug, Deroceras reticulatum (Muller), is probably the most damaging and widespread species of slug, causing severe economic losses in a broad range of crops in temperate zones throughout the world. Investigations into the role of predation in the population dynamics of this species required a biochemical system which was capable of identifying the remains of this slug in the crop contents of predators, and distinguishing them from those of other molluscs. A monoclonal antibody was developed (IgM isotype). This was capable of separating, in an enzyme-linked immunosorbent assay, D. reticulatum from the related D. caruanae (Pollonera) and all molluscs and other invertebrates tested, with the unexpected exceptions of New Zealand flatworms, Artioposthia triangulata (Deny) and the millipede Polymicrodon polydesmoides (Leach). Characterization of the antibody and assay demonstrated that the system could clearly detect as little as 11.6 ng of D. reticulatum protein in 200 mu l of buffer. Slug remains could be identified as such in the crops of the carabid predator Pterostichus melanarius Illiger for 38.1 h, while the antibody-antigen reaction declined to half of that measured immediately following consumption, after 12.9 h. A practical and highly sensitive system was therefore developed, using the first species-specific monoclonal antibody available for the investigation of predation on slugs.