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Hybrid speciation in sparrows I: phenotypic intermediacy,genetic admixture and barriers to gene flow
JO S. HERMANSEN STEIN A. SÆTHER TORE O. ELGVIN THOMAS BORGE ELIN HJELLE GLENN‐PETER SÆTRE 《Molecular ecology》2011,20(18):3812-3822
Homoploid hybrid speciation is thought to require unusual circumstances to yield reproductive isolation from the parental species, and few examples are known from nature. Here, we present genetic evidence for this mode of speciation in birds. Using Bayesian assignment analyses of 751 individuals genotyped for 14 unlinked, nuclear microsatellite loci, we show that the phenotypically intermediate Italian sparrow (Passer italiae) does not form a cluster of its own, but instead exhibits clear admixture (over its entire breeding range) between its putative parental species, the house sparrow (P. domesticus) and the Spanish sparrow (P. hispaniolensis). Further, the Italian sparrow possesses mitochondrial (mt) DNA haplotypes identical to both putative parental species (although mostly of house sparrow type), indicating a recent hybrid origin. Today, the Italian sparrow has a largely allopatric distribution on the Italian peninsula and some Mediterranean islands separated from its suggested parental species by the Alps and the Mediterranean Sea, but co‐occurs with the Spanish sparrow on the Gargano peninsula in southeast Italy. No evidence of interbreeding was found in this sympatric population. However, the Italian sparrow hybridizes with the house sparrow in a sparsely populated contact zone in the Alps. Yet, the contact zone is characterized by steep clines in species‐specific male plumage traits, suggesting that partial reproductive isolation may also have developed between these two taxa. Thus, geographic and reproductive barriers restrict gene flow into the nascent hybrid species. We propose that an origin of hybrid species where the hybrid lineage gets geographically isolated from its parental species, as seems to have happened in this system, might be more common in nature than previously assumed. 相似文献
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GEOFFREY M. REED JOÃO MENDONÇA CORREIA PATRICIA ESPARZA SHEKHAR SAXENA MARIO MAJ 《World psychiatry》2011,10(2):118-131
This article describes the results of the WPA-WHO Global Survey of 4,887
psychiatrists in 44 countries regarding their use of diagnostic classification
systems in clinical practice, and the desirable characteristics of a classification
of mental disorders. The WHO will use these results to improve the clinical
utility of the ICD classification of mental disorders through the current
ICD-10 revision process. Participants indicated that the most important purposes
of a classification are to facilitate communication among clinicians and to
inform treatment and management. They overwhelmingly preferred a simpler system
with 100 or fewer categories, and over two-thirds preferred flexible guidance
to a strict criteria-based approach. Opinions were divided about how to incorporate
severity and functional status, while most respondents were receptive to a
system that incorporates a dimensional component. Significant minorities of
psychiatrists in Latin America and Asia reported problems with the cross-cultural
applicability of existing classifications. Overall, ratings of ease of use
and goodness of fit for specific ICD-10 categories were fairly high, but several
categories were described as having poor utility in clinical practice. This
represents an important focus for the ICD revision, as does ensuring that
the ICD-11 classification of mental disorders is acceptable to psychiatrists
throughout the world. 相似文献
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Yong Hun JO Seung Han OH Bo Mi PARK Dong Hyun Kim Bharat Bhusan PATNAIK Ho Beom LEE Hun Cheon JEONG Yong Seok LEE Kisung KO In Seok Bang Iksoo KIM Yeon Soo HAN 《Entomological Research》2011,41(6):293-293
The tumor suppressor, QM, has been cloned and characterized from various model organisms such as human, plant and invertebrates. Yet, it has not been seriously investigated for its role in conjunction with antiviral mechanisms involving innate insect immunity. From the expressed sequence tag (ESTs) project, conducted with larval cDNA library of cabbage butterfly, Pieris rapae, a partial fragment (718 bp) of QM homologue, termed PrQM containing 660 bp long open reading frame (ORF) encoding protein of 219 amino acids was identified. In silico analysis of PrQM ORF revealed the presence of ribosomal protein L10a/L10e type domain. Phylogenetic analysis of the P. rapae QM‐like protein showed high amino acid sequence similarity with other PrQM polypeptides identified from Heliothis virescenes (95%), Plutella rapae (92%), Bombyx mori (92%), Drosophila melanogaster (89%), and Polyrhachis vicina (85%). The butterfly QM has the closest phylogenetic relationship to a moth (Hv) QM homologue. Further investigations revealed the expression of PrQM at all developmental stages, with pronounced presence at the egg stage. In addition, spatial pattern analysis indicated its high expression in the head, salivary gland, integument and fat body with visible presence in Malpighian tubule and gut. Time course expression studies conducted after immune‐challenge with lipoteichoic acid (LTA) showed the induction of PrQM mRNA at 12 h and 24 h after challenge and also in response to granulovirus (GV). Results of this investigation therefore suggest possible role of QM‐like proteins from Pieris rapae to be involved in innate antiviral immune responses. Further elucidation on the precise function of PrQM during antiviral immune responses by using RNA interference remains a viable research front. 相似文献
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JENNIFER DUMONT DAVID COHEN JOËLLE GÉRARD YVES JOLIVET PIERRE DIZENGREMEL DIDIER LE THIEC 《Plant, cell & environment》2014,37(9):2064-2076
Ozone induces stomatal sluggishness, which impacts photosynthesis and transpiration. Stomatal responses to variation of environmental parameters are slowed and reduced by ozone and may be linked to difference of ozone sensitivity. Here we determine the ozone effects on stomatal conductance of each leaf surface. Potential causes of this sluggish movement, such as ultrastructural or ionic fluxes modification, were studied independently on both leaf surfaces of three Euramerican poplar genotypes differing in ozone sensitivity and in stomatal behaviour. The element contents in guard cells were linked to the gene expression of ion channels and transporters involved in stomatal movements, directly in microdissected stomata. In response to ozone, we found a decrease in the stomatal conductance of the leaf adaxial surface correlated with high calcium content in guard cells compared with a slight decrease on the abaxial surface. No ultrastructural modifications of stomata were shown except an increase in the number of mitochondria. The expression of vacuolar H+/Ca2+‐antiports (CAX1 and CAX3 homologs), β‐carbonic anhydrases (βCA1 and βCA4) and proton H+‐ATPase (AHA11) genes was strongly decreased under ozone treatment. The sensitive genotype characterized by constitutive slow stomatal response was also characterized by constitutive low expression of genes encoding vacuolar H+/Ca2+‐antiports. 相似文献
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PETER J. WANIEK LEILA MENDONÇA‐LIMA GUSTAVO B. MENEZES ANA M. JANSEN CATARINA A. C. ARAÚJO 《Physiological Entomology》2009,34(4):309-317
Insect c‐type lysozymes are antibacterial proteins that are synthesized in different organs with high activity against Gram‐positive bacteria. Because lysozymes possess muramidase activity, they also play an important role in the digestion of bacteria in Diptera. Triatomines express lysozyme‐encoding genes constitutively in the anterior region (cardia and stomach) of the midgut and the fat body after injection of bacteria into the haemocoel. The present study describes the overexpression of the Triatoma brasiliensis lysozyme 1 (lys1) in Escherichia coli. Recombinant T. brasiliensis Lys1 (TbLys1) is purified after solubilization of the inclusion bodies. The protein refolds successfully, showing muramidase activity against Micrococcus lysodeikticus lyophilized cells, after enterokinase cleavage of its thioredoxin fusion protein. In in‐gel zymograms and turbidimetric liquid assays TbLys1 is broadly active under alkaline and acid conditions, indicating a possible digestive function in the two physiologically different midgut regions of the bug: the stomach and small intestine. Muramidase activity is shown in the stomach and small intestine content of unfed bugs and bugs at different days after feeding, respectively. Western blot analysis identifies TbLys1 as lysozyme. 相似文献
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Sun Am KIM Mi Young NOH Yong Hun JO Seung Han OH Iksoo KIM Yong Seok LEE Heung Cheol KIM Sook Jae SEO In Seok BANG Yeon Soo HAN 《Entomological Research》2009,39(2):129-134
The 14-3-3 proteins are known to play an important regulatory role in apoptosis, and various cell signaling cascades. However, no investigation on mosquito 14-3-3 has been reported. To investigate the role of 14-3-3 proteins in mosquito midgut cells undergoing apoptosis, we decided to take advantage of Anopheles gambiae genome data, and were able to find Ag14-3-3ζ cDNA and protein sequences from Ensembl ( http://www.ensembl.org ). Further in silico analysis using BLAST search revealed that Ag14-3-3ζ protein is a polypeptide of 248 amino acids, and shares high identity with 14-3-3ζ homologues from Aedes aegypti (100%), Drosophila melanogaster (96%) and Bombyx mori (93%). Due to the perfect match and high homology, we hypothesized that Ag14-3-3ζ peptide antibody may recognize 14-3-3ζ homologs from other anopheline mosquitoes and insects. We thus generated 14-3-3ζ polyclonal antibody against a unique region located in the C-terminal end of Ag14-3-3ζ after in silico epitope analysis. As expected, zoo-western blot analysis of 14-3-3 proteins revealed that a polyclonal antibody against Ag14-3-3ζ peptide recognizes 14-3-3 homologs from dipteran and lepidopteran insects. To our knowledge, this is the first report on polyclonal antibody production against mosquito 14-3-3ζ. The mosquito-based 14-3-3ζ antibody will be very useful for studying the functional characterization of 14-3-3ζ in the context of host–pathogen interactions in midgut and other immune cells. 相似文献
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PAUL MELLOY GRANT HOLLAWAY JO LUCK ROB NORTON ELIZABETH AITKEN SUKUMAR CHAKRABORTY 《Global Change Biology》2010,16(12):3363-3373
Rising atmospheric carbon dioxide (CO2) concentration is increasingly affecting food production but how plant diseases will influence production and quality of food under rising CO2 is not well understood. With increased plant biomass at high CO2 the stubble‐borne fungal pathogen Fusarium pseudograminearum causing crown rot (CR) of wheat may become more severe. We have studied inoculum production by Fusarium using fungal biomass per unit wheat stubble, stem browning from CR and the saprophytic fitness of Fusarium strains isolated from two wheat varieties grown in 2007 and 2008 at ambient and elevated CO2 in free‐air CO2 enrichment (FACE) with or without irrigation and once in a controlled environment. Fungal biomass, determined using primers for fungal ribosomal 18s and the TRI5 gene, increased significantly at elevated CO2 in two of the three studies. Stem browning increased significantly at elevated CO2 in the 2007 FACE study. At elevated CO2 increased stem browning was not influenced by irrigation in a susceptible variety but in a resistant variety stem browning increased by 68% without irrigation. Wheat variety was significant in regression models explaining stem browning and Fusarium biomass but pathogen biomass at the two CO2 levels was not significantly linked to stem browning. Fusarium isolates from ambient and elevated CO2 did not differ significantly in their saprophytic fitness measured by the rate of colonization of wheat straw. We show that under elevated CO2Fusarium inoculum in stubbles will be amplified from increased crop and pathogen biomass while unimpeded saprophytic fitness will retain its effectiveness. If resistant varieties cannot completely stop infection, Fusarium will rapidly colonize stubble to further increase inoculum once the crop is harvested. Research should move beyond documenting the influence of elevated CO2 to developing disease management strategies from improved knowledge of pathogen biology and host resistance under rising CO2. 相似文献