从小鼠11.5d胚胎cDNA文库中筛选Dishevelled2相互作用蛋白

Dishevelled (Dvl)是个多功能、进化上非常保守的蛋白,在Wnt信号传导通路中起着重要的作用。为了研究Dishevelled介导Wnt信号传递的分子机制,利用GAL4酵母双杂交系统筛选了小鼠11．5d胚胎cDNA库,发现了15个可与小鼠Dvl2 DEP结构域和羧基端相互作用的蛋白质。将阳性库质粒测序并对测序结果做BLAST分析,发现其中一个阳性克隆是编码Gli3蛋白氨基端(6—122aa)的cDNA片段,从而暗示Gli3蛋白可能与Dishevelled一起作用并参与某些生物学过程。     

Interdependence of Cell Cycle Events in Tetrahymena thermophila: Formation of Contractile Vacuole Pore and Fission Gap in Ciliary Meridians*

SYNOPSIS The formation of the contractile vacuole pore (CVP) in Tetrahymena thermophila. genotype mol^b/mol^b is temporally and spatially associated with the formation of the fission gap in the CVP meridian. New CVPs arise when fission gaps appear in CVP meridians, the new pores being found anterior to the gaps. When, however, CVP meridians are rotated 180°, the fission gaps develop late. In more than 1/3 of the 180°-rotated CVP meridians, the new CVPs are formed before the appearance of the fission gap. Evidently, the appearance of the gap is not a prerequisite for CVP formation. Nevertheless, mutants exist in which the absence of fission gap and CVP are correlated in some cases and in which the presence of supernumerary fission gap and CVP are correlated in other instances. It is suggested that the 2 developmental events, although not causally related to each other, may be controlled by a common morpho-genetic signal. This commits a certain site (mid-body) along a ciliary meridian to develop the fission gap as well as the CVP; however, after this step of commitment, the appearance of the fission gap is delayed in 180°-rotated CVP meridians.     

Genetic differentiation among populations of a Hispaniolan trunk anole that exhibit geographical variation in dewlap colour

Long neglected by classic island biogeographical theory, speciation within and among islands is increasingly recognized as a major contributor to insular diversity. Although the factors responsible for island speciation remain poorly understood, this process appears critically dependent on geographical variation and speciation in allopatry or parapatry. Here, we investigate geographical variation and speciation in a complex of Hispaniolan trunk anoles (Anolis distichus), where populations with strikingly distinct dewlap colours and patterns correspond with deeply divergent mtDNA structure. Using a multilocus, population‐level analysis, we investigate whether these phenotypically and mitochondrially distinct populations exhibit the type of nuclear differentiation expected among species or incipient species. Along a transect that extends across a recently recessed marine barrier, our results are consistent with the persistence of an abrupt phenotypic and mitochondrial transition following secondary contact, in spite of little or no evidence for a reduction in nuclear gene flow. Along a second transect extending across a steep environmental gradient, our phenotypic and microsatellite data suggest a sharp genetic break with little or no admixture, whereas mtDNA recovers a signature of extensive unidirectional introgression. Together, these results are consistent with previous studies of Lesser Antillean anoles, suggesting that allopatric divergence alone is insufficient for speciation, whereas reduced gene flow and partial reproductive isolation may accumulate in the presence of ecological gradients.     

Phyllotaxis in the Oil Palm: Arrangement of Male/Female Florets along the Spikelets

The paper continues an earlier study of the geometry of inflorescencestructures in the oil palm in which geometry is measured interms of Equivalent Phyllotaxis Index (E.P.I.). In this casethe phyllotaxis of male and female florets along their respectivespikelets is considered. Regardless of the spikelet positionon the inflorescence or the palm age the very small male floretshave a higher E.P.I. than the large female structures and acompletely different apparent parastichy arrangement. TheseE.P.I. estimates seem to be independent of the age of palmsfrom which inflorescences and hence spikelets are sampled. However,there is considerable variation in phyllotaxis within bunches,E.P.I. being lower on spikelets sampled toward the base of theinflorescence and increasing in a more or less linear mannerin spikelets sampled at the tip; this pattern is not so definiteon male spikelets. The results are discussed in relation toother more simple measurements of spikelet architecture.     

Population Genetics of the Washington National Primate Research Center's (WaNPRC) Captive Pigtailed Macaque (Macaca nemestrina) Population

Pigtailed macaques (Macaca nemestrina) provide an important model for biomedical research on human disease and for studying the evolution of primate behavior. The genetic structure of captive populations of pigtailed macaques is not as well described as that of captive rhesus (M. mulatta) or cynomolgus (M. fascicularis) macaques. The Washington National Primate Research Center houses the largest captive colony of pigtailed macaques located in several different housing facilities. Based on genotypes of 18 microsatellite (short tandem repeat [STR]) loci, these pigtailed macaques are more genetically diverse than captive rhesus macaques and exhibit relatively low levels of inbreeding. Colony genetic management facilitates the maintenance of genetic variability without compromising production goals of a breeding facility. The periodic introduction of new founders from specific sources to separate housing facilities at different times influenced the colony's genetic structure over time and space markedly but did not alter its genetic diversity significantly. Changes in genetic structure over time were predominantly due to the inclusion of animals from the Yerkes National Primate Research Center in the original colony and after 2005. Strategies to equalize founder representation in the colony have maximized the representation of the founders’ genomes in the extant population. Were exchange of animals among the facilities increased, further differentiation could be avoided. The use of highly differentiated animals may confound interpretations of phenotypic differences due to the inflation of the genetic contribution to phenotypic variance of heritable traits. Am. J. Primatol. 74:1017‐1027, 2012. © 2012 Wiley Periodicals, Inc.     

论山东、辽宁寒武系炒米店组底部(古丈阶顶部)小凤凰虫(Fenghuangella Yang in Zhou et al.,1977)北大核心

本文对在山东济南市钢城区九龙山和辽宁东部大连市白家山寒武系炒米店组底部报道的小凤凰虫,进行了详细的描述及修订。根据与小凤凰虫共生的三叶虫对于华北地台区苗岭统与芙蓉统的界线进行了深入探讨,将产有小凤凰虫的Liostracina simesi-Placosema convexa组合带作为华北地台区苗岭统古丈阶最上部的一个化石带,而将Prochuangia mansuyi的首现作为华北地台区芙蓉统排碧阶的底界,对于华南斜坡相区和华北地台区苗岭统和芙蓉统之间界线划分和对比具有重要意义。     

Ultrastructural Features of the Oral Region of Amicronucleate Paramecium tetraurelia in Autogamy1

ABSTRACT Amicronucleate Paramecium tetraurelia fails to develop an oral apparatus but resorbs the pre-existing one in the sexual cycle. Previous cytological studies have revealed the presence of a shallow, oral depression with a few scattered basal bodies after autogamy or conjugation. The present ultrastructural study of the ectoplasm beneath the oral depression revealed only the presence of a disorganized filamentous reticulum and small blocks of cytopharyngeal ribbons. In addition, beneath the oral depression, a large number of discoidal vesicles were found, similar to but larger in diameter than those normally associated with the cytopharynx of vegetative cells. The oral structures found in amicronucleates in autogamy might be remnants of the pre-existing oral apparatus, but the possibility that they were newly developed was not excluded. The morphogenetic interest of these structures was discussed. It is evident that amicronucleates in autogamy do not develop an extensive oral ultrastructural organization.     

Comparing genetic variants detected in the 1000 genomes project with SNPs determined by the International HapMap Consortium

Single-nucleotide polymorphisms (SNPs) determined based on SNP arrays from the international HapMap consortium (HapMap) and the genetic variants detected in the 1000 genomes project (1KGP) can serve as two references for genomewide association studies (GWAS). We conducted comparative analyses to provide a means for assessing concerns regarding SNP array-based GWAS findings as well as for realistically bounding expectations for next generation sequencing (NGS)-based GWAS. We calculated and compared base composition, transitions to transversions ratio, minor allele frequency and heterozygous rate for SNPs from HapMap and 1KGP for the 622 common individuals. We analysed the genotype discordance between HapMap and 1KGP to assess consistency in the SNPs from the two references. In 1KGP, 90.58% of 36,817,799 SNPs detected were not measured in HapMap. More SNPs with minor allele frequencies less than 0.01 were found in 1KGP than HapMap. The two references have low discordance (generally smaller than 0.02) in genotypes of common SNPs, with most discordance from heterozygous SNPs. Our study demonstrated that SNP array-based GWAS findings were reliable and useful, although only a small portion of genetic variances were explained. NGS can detect not only common but also rare variants, supporting the expectation that NGS-based GWAS will be able to incorporate a much larger portion of genetic variance than SNP arrays-based GWAS.     

Borrelia burgdorferi infection in Ixodes ricinus from habitats in Denmark

A total of 2647 ticks of the genus Ixodes was sampled by flagging the vegetation in thirty-one sites in eastern Jutland, Denmark. All ticks were identified as Ixodes ricinus Linnaeus. A total of 317 ticks (202 nymphs and 115 adults) from three different sites were examined for the spirochaete Borrelia burgdorferi Johnson et al. by indirect fluorescent antibody staining; the frequency of infection varied from 7% to 22%. It is concluded that I. ricinus, known to be the most common tick in Denmark, is the vector largely responsible for the transmission of B. burgdorferi in this country.