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<正>Rapid and efficient isolation of unknown flanking DNA sequences adjacent to known regions is important for molecular biology research.For this purpose,several PCR-based methods have been reported,including inverse PCR(Uchiyama and Watanabe,2006),ligation-mediated PCR(Yan et al.,2003;Ballester et al.,2005;Wang et al.,2007;Trinh et al.,2012)and randomly primed PCR(Liu and Whittier,1995;Liu et al.,1995;Antal et al."2004;Liu and Chen,2007;Reddy et al.,2008;Wang  相似文献   

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灵长类动物类固醇激素的研究已经在很多物种间展开(Cariso et al.,1999;Lutz et al.,2000;He et al.,2001;Yan and Jiang,2006;Brandon et al.,2008;Lu et al.,2010;Kim et al.,2012)。特别是对于没有明显发情特征的灵长类动物,类固醇激素的变化可以为它们的繁殖状态提供更多可靠的评估(Fujita et al.,2001)。自然状态下野生动  相似文献   

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大鳞副泥鳅雄核单倍体的早期发育   总被引:4,自引:0,他引:4  
目前,有关鱼类雄核发育的研究已见于川鲽(Platichthys flesus)、马苏大麻哈鱼(Oncorhynchus masou)、虹鳟(Oncorhynchus mykiss)、红点溪鳟(Salvelinus fontinalis)、鲤鱼(Cyprnus carpio)、尼罗罗非鱼(Oreochromis niloticus)、泥鳅(Misgurnus anguillicaudatus)、斑马鱼(Danio rerio)等(Purdom,1969;Arai et al., 1979; Scheerer et al., 1991; May et al., 1988; Bongers et al., 1994;Grunina et al., 1990; Meyers, 1995; Masaoka et al., 1995; 赵振山等,1998;Corley-Smith et al., 1996).  相似文献   

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The limited capability to regenerate new neurons following injuries of the central neural system (CNS) still remains a major challenge for basic and clinical neuroscience.Neural stem cells (NSCs) could nearly have the potential to differentiate into all kinds of neural cells in vitro.Previous studies verified that exogenous transplanted NSCs are capable of differentiating into neurons and projecting onto the host neurons in the rat brain (Tabar et al.,2005;Dong JR et al.,2012),which could lead to behavioral recovery from neuronal damages such as spinal cord injury (McDonald et al.,1999),Parkinson's disease (Gonzalez et al.,2015;Kim et al.,2002;Lindvall,2001),and stroke (Zhang et al.,2016).  相似文献   

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Dear Editor, Phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) islocated at an important branch point in the carbohydratemetabolism of plants. The enzyme is a homotetramer andcatalyzes the addition of bicarbonate to phosphoenolpyru-vate (PEP) to form oxaloacetate and phosphate. PEPC isregulated by metabolites and phosphorylation. AIIostericfeedback inhibition is mainly regulated by L-malate andL-aspartate which bind to a site separated from the activecenter (Kai et al., 1999; Paulus et al., 2013). Structure analy-sis of PEPC from Escherichia coli (Kai et al., 1999; Matsumuraet al., 2002), Zea rnays (Matsumura et al., 2002), Flaveria trin-ervia, and F. pringlei (Paulus et al., 2013) revealed that thesubstrate PEP and the feedback inhibitors bind to separatesites within each monomer.  相似文献   

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Aquatic hyphomycetes on submerged fallen leaves and deadwoods have been numerously reported in fast running streams in temperate countries(Ingold,1976;Ingold,1979;Chauvet,1990;Barlocher & Rosset,1987;Barlocher et al.,1995;Descals et al.,1995).However,documented information is considerably limited in African countries(Ingold,1956;Dixon,1959;Le-John,1965;Ferreira et al.,1981),and unavailable in Cameroon,a country mostly covered with heavy tropical forests(Loung,1980).This paper is to present a list of aquatic and aeroaquatic hyphomycetes identified from foam samples collected in Cameroon during a two-year survey.  相似文献   

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正Dwarfism is an important plant architecture trait in crop breeding(Peng et al.,1999;Sasaki el al.,2002).In cucurbits.the compact plant type was proposed to develop new varieties for the once-over mechanical harvest for concentrated fruit set and higher densities(Li et al.,2011;Mondal et al.,2011).Several recessive genes in cucurbits have been reported to confer the phenotype of short internodes or bushy plant habits,such as compact,cp-2,and dw in cucumber(Cucumis sativus  相似文献   

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利用活体观察和蛋白银染色技术对近年来采自青岛、大亚湾、湛江沿岸水体的10个海洋寡毛类纤毛虫种: 侧扁急游虫Strombidium apolatum Wilbert & Song, 2005、具头急游虫Strombidium capitatum (Leegaard, 1995) Kahl, 1932、广东急游虫Strombidium guangdongense Liu, et al., 2016、拟卡氏急游虫Strombidium paracalkinsi (Lei, et al., 1999) Agatha, 2004、拟楔尾急游虫Strombidium parastylifer Song, et al., 2009、铃木急游虫Strombidium suzukii Song, et al., 2009、束腰旋游虫Spirostrombidium cinctum (Kahl, 1932) Petz, et al., 1995、杨科夫平游虫Parallelostrombidium jankowski (Song, et al., 2009) Song, et al., 2018、卡尔平游虫Parallelostrombidium kahli (Song, et al., 2009) Song, et al., 2018、最小拟盗虫Strombidinopsis minima (Gruber, 1884) Song & Bradbury, 1998的形态学开展了比较研究, 补充和厘定了有关形态特征、纤毛图式以及性状变异等分类学新信息。  相似文献   

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<正>Dear Editor,Avian Influenza virus(AIV)H9N2 subtype viruses circulate widely in domestic fowl,and usually cause mild clinical signs in poultry(Li et al.,2005).Occasionally,avian H9N2 can infect humans and cause mild clinical symptoms(Peiris et al.,1999;Lin et al.,2000).Genetic analysis indicates that the H9N2 genotype viruses exist in major poultry species(such as duck and chicken)and in minor poultry species(such as quail,partridge,chukar,pheasant,and guinea fowl)(Guan et al.,2000;Li et al.,2005).Meanwhile,frequent reassortment events among  相似文献   

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山地麻蜥继饥饿后的补偿生长   总被引:7,自引:0,他引:7  
许雪峰  吴义莲 《动物学报》2002,48(5):700-703
动物继饥饿后一段时间后恢复喂食,在恢复生长阶段中常出现高于正常生长速度的补偿生长现象.有关脊椎动物补偿增长的研究主要集中在畜禽类、哺乳类和鱼类(Wilson et al.,1960;Plavnik et al.,1985;Drew et al.,1975;Pitts,1986;Kim et al.,1995),并且已在一些经济动物的饲养中利用补偿增长效应而提高经济效益.爬行动物是否存在补偿生长的现象迄今不明.本研究以山地麻蜥(Eremias breuchleyi)作为实验对象,研究其继饥饿后的补偿生长,预期为揭示爬行动物饥饿胁迫条件下的生长对策提供基础资料.  相似文献   

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On the origin of the Hirudinea and the demise of the Oligochaeta   总被引:10,自引:0,他引:10  
The phylogenetic relationships of the Clitellata were investigated with a data set of published and new complete 18S rRNA gene sequences of 51 species representing 41 families. Sequences were aligned on the basis of a secondary structure model and analysed with maximum parsimony and maximum likelihood. In contrast to the latter method, parsimony did not recover the monophyly of Clitellata. However, a close scrutiny of the data suggested a spurious attraction between some polychaetes and clitellates. As a rule, molecular trees are closely aligned with morphology-based phylogenies. Acanthobdellida and Euhirudinea were reconciled in their traditional Hirudinea clade and were included in the Oligochaeta with the Branchiobdellida via the Lumbriculidae as a possible link between the two assemblages. While the 18S gene yielded a meaningful historical signal for determining relationships within clitellates, the exact position of Hirudinea and Branchiobdellida within oligochaetes remained unresolved. The lack of phylogenetic signal is interpreted as evidence for a rapid radiation of these taxa. The placement of Clitellata within the Polychaeta remained unresolved. The biological reality of polytomies within annelids is suggested and supports the hypothesis of an extremely ancient radiation of polychaetes and emergence of clitellates.  相似文献   

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Data on the ontogeny of the posterior haptor of monogeneans were obtained from more than 150 publications and summarised. These data were plotted into diagrams showing evolutionary capacity levels based on the theory of a progressive evolution of marginal hooks, anchors and other attachment components of the posterior haptor in the Monogenea (Malmberg, 1986). 5 + 5 unhinged marginal hooks are assumed to be the most primitive monogenean haptoral condition. Thus the diagrams were founded on a 5 + 5 unhinged marginal hook evolutionary capacity level, and the evolutionary capacity levels of anchors and other haptoral attachement components were arranged according to haptoral ontogenetical sequences. In the final plotting diagram data on hosts, type of spermatozoa, oncomiracidial ciliation, sensilla pattern and protonephridial systems were also included. In this way a number of correlations were revealed. Thus, for example, the number of 5 + 5 marginal hooks correlates with the most primitive monogenean type of spermatozoon and with few sensillae, many ciliated cells and a simple protonephridial system in the oncomiracidium. On the basis of the reviewed data it is concluded that the ancient monogeneans with 5 + 5 unhinged marginal hooks were divided into two main lines, one retaining unhinged marginal hooks and the other evolving hinged marginal hooks. Both main lines have recent representatives at different marginal hook evolutionary capacity levels, i.e. monogeneans retaining a haptor with only marginal hooks. For the main line with hinged marginal hooks the name Articulon-choinea n. subclass is proposed. Members with 8 + 8 hinged marginal hooks only are here called Proanchorea n. superord. Monogeneans with unhinged marginal hooks only are here called Ananchorea n. superord. and three new families are erected for its recent members: Anonchohapteridae n. fam., Acolpentronidae n. fam. and Anacanthoridae n. fam. (with 7 + 7, 8 + 8 and 9 + 9 unhinged marginal hooks, respectively). Except for the families of Articulonchoinea (e.g. Acanthocotylidae, Gyrodactylidae, Tetraonchoididae) Bychowsky's (1957) division of the Monogenea into the Oligonchoinea and Polyonchoinea fits the proposed scheme, i.e. monogeneans with unhinged marginal hooks form one old group, the Oligonchoinea, which have 5 + 5 unhinged marginal hooks, and the other group form the Polyonchoinea, which (with the exception of the Hexabothriidae) has a greater number (7 + 7, 8 + 8 or 9 + 9) of unhinged marginal hooks. It is proposed that both these names, Oligonchoinea (sensu mihi) and Polyonchoinea (sensu mihi), will be retained on one side and Articulonchoinea placed on the other side, which reflects the early monogenean evolution. Except for the members of Ananchorea [Polyonchoinea], all members of the Oligonchoinea and Polyonchoinea have anchors, which imply that they are further evolved, i.e. have passed the 5 + 5 marginal hook evolutionary capacity level (Malmberg, 1986). There are two main types of anchors in the Monogenea: haptoral anchors, with anlages appearing in the haptor, and peduncular anchors, with anlages in the peduncle. There are two types of haptoral anchors: peripheral haptoral anchors, ontogenetically the oldest, and central haptoral anchors. Peduncular anchors, in turn, are ontogenetically younger than peripheral haptoral anchors. There may be two pairs of peduncular anchors: medial peduncular anchors, ontogentically the oldest, and lateral peduncular anchors. Only peduncular (not haptoral) anchors have anchor bars. Monogeneans with haptoral anchors are here called Mediohaptanchorea n. superord. and Laterohaptanchorea n. superord. or haptanchoreans. All oligonchoineans and the oldest polyonchoineans are haptanchoreans. Certain members of Calceostomatidae [Polyonchoinea] are the only monogeneans with both (peripheral) haptoral and peduncular anchors (one pair). These monogeneans are here called Mixanchorea n. superord. Polyonchoineans with peduncular anchors and unhinged marginal hooks are here called the Pedunculanchorea n. superord. The most primitive pedunculanchoreans have only one pair of peduncular anchors with an anchor bar, while the most advanced have both medial and lateral peduncular anchors; each pair having an anchor bar. Certain families of the Articulonchoinea, the Anchorea n. superord., also have peduncular anchors (parallel evolution): only one family, the Sundanonchidae n. fam., has both medial and lateral peduncular anchors, each anchor pair with an anchor bar. Evolutionary lines from different monogenean evolutionary capacity levels are discussed and a new system of classification for the Monogenea is proposed.In agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. EditorIn agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. Editor  相似文献   

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