596 research outputs found

    A putative origin of the insect chemosensory receptor superfamily in the last common eukaryotic ancestor

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    The insect chemosensory repertoires of Odorant Receptors (ORs) and Gustatory Receptors (GRs) together represent one of the largest families of ligand-gated ion channels. Previous analyses have identified homologous 'Gustatory Receptor-Like (GRL)' proteins across Animalia, but the evolutionary origin of this novel class of ion channels is unknown. We describe a survey of unicellular eukaryotic genomes for GRLs, identifying several candidates in fungi, protists and algae that contain many structural features characteristic of animal GRLs. The existence of these proteins in unicellular eukaryotes, together with ab initio protein structure predictions, provide evidence for homology between GRLs and a family of uncharacterized plant proteins containing the DUF3537 domain. Together, our analyses suggest an origin of this protein superfamily in the last common eukaryotic ancestor

    Gene Duplication and Gain in the Trematode Atriophallophorus winterbourni Contributes to Adaptation to Parasitism.

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    Gene duplications and novel genes have been shown to play a major role in helminth adaptation to a parasitic lifestyle because they provide the novelty necessary for adaptation to a changing environment, such as living in multiple hosts. Here we present the de novo sequenced and annotated genome of the parasitic trematode Atriophallophorus winterbourni and its comparative genomic analysis to other major parasitic trematodes. First, we reconstructed the species phylogeny, and dated the split of A. winterbourni from the Opisthorchiata suborder to approximately 237.4 Ma (±120.4 Myr). We then addressed the question of which expanded gene families and gained genes are potentially involved in adaptation to parasitism. To do this, we used hierarchical orthologous groups to reconstruct three ancestral genomes on the phylogeny leading to A. winterbourni and performed a GO (Gene Ontology) enrichment analysis of the gene composition of each ancestral genome, allowing us to characterize the subsequent genomic changes. Out of the 11,499 genes in the A. winterbourni genome, as much as 24% have arisen through duplication events since the speciation of A. winterbourni from the Opisthorchiata, and as much as 31.9% appear to be novel, that is, newly acquired. We found 13 gene families in A. winterbourni to have had more than ten genes arising through these recent duplications; all of which have functions potentially relating to host behavioral manipulation, host tissue penetration, and hiding from host immunity through antigen presentation. We identified several families with genes evolving under positive selection. Our results provide a valuable resource for future studies on the genomic basis of adaptation to parasitism and point to specific candidate genes putatively involved in antagonistic host-parasite adaptation

    Real time sonography as an anatomy teaching aid in undergraduate radiography institutions in Northern Nigeria

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    Background: Real-time ultrasound scanning is increasing in popularity as a teaching tool for human anatomy because it is non-invasive, offers real-time 3-D anatomy and is cheaper than dissections.Objectives: To assess real-time ultrasound scanning as a teaching method of human anatomy, and to determine what teaching methods radiography students consider effective for understanding human anatomy.Materials and methods: One hundred and ten self-administered, structured and pre-tested questionnaires were distributed to Clinical Radiography students (Third, fourth and fifth year)in Northern Nigeria featuring University of Maiduguri and Bayero University Kano. The questionnaire consists of two sections;Demographics and preferred methods of delivery of anatomical information. Participation was voluntary. Comparisons among teaching methods were made using repeated measures ANOVA.Results: A significant difference among the eight delivery methods with 3-D Radiology imaging being as the most preferred method overall (48.17, p<0.0001) and ultrasound the least (32.48, p<0.0001). With Duncan’s multiple Range test, it is clearly shown that 3-D Radiology imaging differ with mean value(5.2522) followed by Computer programs(5.1292), Anatomic models(4.7593), Laboratory videos(4.5815), textbooks(4.5358), animal dissection(4.2568), lectures(3.2568) and finally ultrasound scan (3.6087), (P<0.0001).Conclusion: 3-D Radiology imaging is the most preferred method of delivering anatomical information and ultrasound scanning is the least preferred method.Keywords: Real time sonography, radiography institutions, Northern Nigeria

    Kesan penggunaan mnemonik “siasat” berbantukan jadual pendaraban indeks dan pembelajaran koperatif terhadap pencapaian matematik pelajar berpencapaian rendah

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    Pelajar berpencapian rendah sering mengalami masalah dalam pembelajaran matematik khasnya dalam Pendaraban Indeks, salah satu tajuk yang perlu dikuasai oleh pelajar. Oleh itu, kajian ini bertujuan untuk menentukan kesan penggunaan teknik mnemonik akronim SIASAT berbantukan jadual pendaraban indeks dan pembelajaran koperatif ‘Think-Pair-Share’ terhadap pencapaian pelajar Tingkatan Tiga berpencapaian rendah dalam pendaraban indeks. Kajian kuantitatif ini menggunakan reka bentuk kuasi eksperimen dimana dua kumpulan ditetapkan, iaitu 40 orang pelajar dalam kumpulan kawalan dan 40 lagi pelajar dalam kumpulan rawatan. Kumpulan kawalan telah mengikuti pembelajaran konvensional berpusatkan guru manakala kumpulan rawatan didedahkan kepada penggunaan mnemonik akronim SIASAT, jadual pendaraban indeks dan pembelajaran koperatif Think-Pair-Share. Dapatan kajian menunjukkan pelajar dalam kedua-dua kumpulan meningkatkan skor markah mereka daripada ujian pra kepada ujian pasca. Walau bagaimanapun, pencapaian pelajar dalam kumpulan rawatan jauh lebih baik berbanding kumpulan kawalan. Kajian ini telah menunjukkan keberkesanan penggunaan mnemonik akronim SIASAT, jadual pendaraban indeks dan pembelajaran koperatif Think-Pair-Share dalam meningkatkan pencapaian pelajar dalam pendaraban indeks. Justeru, guru-guru perlu kreatif dan inovatif serta proaktif dalam membangunkan pelbagai pendekatan, teknik dan bahan bantu mengajar bagi membantu pelajar berpencapaian rendah dalam pembelajaran matematik

    Continuous-Flow Synthesis of Arylthio-Cyclopropyl Carbonyl Compounds

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    The straightforward, continuous-flow synthesis of cyclopropyl carbaldehydes and ketones has been developed starting from 2-hydroxycyclobutanones and aryl thiols. This acid-catalyzed mediated procedure allows access to the multigram and easily scalable synthesis of cyclopropyl adducts under mild conditions, using reusable Amberlyst-35 as a catalyst. The resins, suitably ground and used for filling steel columns, have been characterized via TGA, ATR, SEM and BET analyses to describe the physical-chemical properties of the packed bed and the continuous-flow system in detail. To highlight the synthetic versatility of the arylthiocyclopropyl carbonyl compounds, a series of selective oxidation reactions have been performed to access sulfoxide and sulfone carbaldehyde cyclopropanes, oxiranes and carboxylic acid derivatives

    Arabidopsis HAP2/GCS1 is a gamete fusion protein homologous to somatic and viral fusogens

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    Cell–cell fusion is inherent to sexual reproduction. Loss of HAPLESS 2/GENERATIVE CELL SPECIFIC 1 (HAP2/GCS1) proteins results in gamete fusion failure in diverse organisms, but their exact role is unclear. In this study, we show that Arabidopsis thaliana HAP2/GCS1 is sufficient to promote mammalian cell–cell fusion. Hemifusion and complete fusion depend on HAP2/GCS1 presence in both fusing cells. Furthermore, expression of HAP2 on the surface of pseudotyped vesicular stomatitis virus results in homotypic virus–cell fusion. We demonstrate that the Caenorhabditis elegans Epithelial Fusion Failure 1 (EFF-1) somatic cell fusogen can replace HAP2/GCS1 in one of the fusing membranes, indicating that HAP2/GCS1 and EFF-1 share a similar fusion mechanism. Structural modeling of the HAP2/GCS1 protein family predicts that they are homologous to EFF-1 and viral class II fusion proteins (e.g., Zika virus). We name this superfamily Fusexins: fusion proteins essential for sexual reproduction and exoplasmic merger of plasma membranes. We suggest a common origin and evolution of sexual reproduction, enveloped virus entry into cells, and somatic cell fusion

    OMA orthology in 2021: website overhaul, conserved isoforms, ancestral gene order and more.

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    OMA is an established resource to elucidate evolutionary relationships among genes from currently 2326 genomes covering all domains of life. OMA provides pairwise and groupwise orthologs, functional annotations, local and global gene order conservation (synteny) information, among many other functions. This update paper describes the reorganisation of the database into gene-, group- and genome-centric pages. Other new and improved features are detailed, such as reporting of the evolutionarily best conserved isoforms of alternatively spliced genes, the inferred local order of ancestral genes, phylogenetic profiling, better cross-references, fast genome mapping, semantic data sharing via RDF, as well as a special coronavirus OMA with 119 viruses from the Nidovirales order, including SARS-CoV-2, the agent of the COVID-19 pandemic. We conclude with improvements to the documentation of the resource through primers, tutorials and short videos. OMA is accessible at https://omabrowser.org

    OMA orthology in 2021: website overhaul, conserved isoforms, ancestral gene order and more

    Get PDF
    OMA is an established resource to elucidate evolutionary relationships among genes from currently 2326 genomes covering all domains of life. OMA provides pairwise and groupwise orthologs, functional annotations, local and global gene order conservation (synteny) information, among many other functions. This update paper describes the reorganisation of the database into gene-, group- and genome-centric pages. Other new and improved features are detailed, such as reporting of the evolutionarily best conserved isoforms of alternatively spliced genes, the inferred local order of ancestral genes, phylogenetic profiling, better cross-references, fast genome mapping, semantic data sharing via RDF, as well as a special coronavirus OMA with 119 viruses from the Nidovirales order, including SARS-CoV-2, the agent of the COVID-19 pandemic. We conclude with improvements to the documentation of the resource through primers, tutorials and short videos. OMA is accessible at https://omabrowser.org
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