664 research outputs found

    Livestock Depredation by Grizzly Bears on Forest Service Grazing Allotments in the Greater Yellowstone Ecosystem

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    Grizzly bear population growth and range expansion over the last several decades in the Greater Yellowstone Ecosystem (GYE) has led to increased human-bear conflicts, including livestock depredation. In 2015, we began a study to evaluate spatio-temporal relationships between livestock grazing, grizzly bear habitat characteristics, and livestock depredations by grizzly bears on public lands in the GYE during 1992–2014. In collaboration with the U.S. Forest Service (USFS), Interagency Grizzly Bear Study Team, and National Park Service, we have obtained 23 years of grazing allotment attributes for 316 USFS and Grand Teton National Park grazing allotments including: livestock stocking information, grizzly bear habitat characteristics, grizzly bear density and distribution, and livestock depredation counts. Overall counts of livestock depredation events, total livestock killed, and the number of allotments experiencing depredations increased from 1992 to 2014, concurrent with range expansion and increasing grizzly bear densities. Annual depredation events per allotment differed by livestock class, where allotments stocked with cow-calf pairs and sheep experienced the majority of depredations. Livestock depredation counts will be modeled with livestock stocking data and grizzly bear habitat variables to better understand which attributes of grazing allotments had the greatest association with the number of depredations over the study period. We will evaluate habitat attributes at two spatial scales, representing daily and annual grizzly bear activity areas. Our results will enhance adaptive approaches to conserve grizzly bears, while also maintaining the economic viability of livestock operations

    The BioGRID Interaction Database: 2011 update

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    The Biological General Repository for Interaction Datasets (BioGRID) is a public database that archives and disseminates genetic and protein interaction data from model organisms and humans (http://www.thebiogrid.org). BioGRID currently holds 347 966 interactions (170 162 genetic, 177 804 protein) curated from both high-throughput data sets and individual focused studies, as derived from over 23 000 publications in the primary literature. Complete coverage of the entire literature is maintained for budding yeast (Saccharomyces cerevisiae), fission yeast (Schizosaccharomyces pombe) and thale cress (Arabidopsis thaliana), and efforts to expand curation across multiple metazoan species are underway. The BioGRID houses 48 831 human protein interactions that have been curated from 10 247 publications. Current curation drives are focused on particular areas of biology to enable insights into conserved networks and pathways that are relevant to human health. The BioGRID 3.0 web interface contains new search and display features that enable rapid queries across multiple data types and sources. An automated Interaction Management System (IMS) is used to prioritize, coordinate and track curation across international sites and projects. BioGRID provides interaction data to several model organism databases, resources such as Entrez-Gene and other interaction meta-databases. The entire BioGRID 3.0 data collection may be downloaded in multiple file formats, including PSI MI XML. Source code for BioGRID 3.0 is freely available without any restrictions

    Head-to-tail cyclization of side chain-protected linear peptides to recapitulate genetically-encoded cyclized peptides

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    Genetically‐encoded cyclic peptide libraries allow rapid in vivo screens for inhibitors of any target protein of interest. In particular, the Split Intein Circular Ligation of Protein and Peptides (SICLOPPS) system exploits spontaneous protein splicing of inteins to produce intracellular cyclic peptides. A previous SICLOPPS screen against Aurora B kinase, which plays a critical role during chromosome segregation, identified several candidate inhibitors that we sought to recapitulate by chemical synthesis. We describe the syntheses of cyclic peptide hits and analogs via solution‐phase macrocyclization of side chain‐protected linear peptides obtained from standard solid‐phase peptide synthesis. Cyclic peptide targets, including cyclo‐[CTWAR], were designed to match both the variable portions and conserved cysteine residue of their genetically‐encoded counterparts. Synthetic products were characterized by tandem high‐resolution mass spectrometry to analyze a combination of exact mass, isotopic pattern, and collisional dissociation‐induced fragmentation pattern. The latter analyses facilitated the distinction between targets and oligomeric side products, and served to confirm peptidic sequences in a manner that can be readily extended to analyses of complex biological samples. This alternative chemical synthesis approach for cyclic peptides allows cost‐effective validation and facile chemical elaboration of hit candidates from SICLOPPS screens

    Genomic islands of speciation separate cichlid ecomorphs in an East African crater lake

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    The genomic causes and effects of divergent ecological selection during speciation are still poorly understood. Here, we report the discovery and detailed characterization of early-stage adaptive divergence of two cichlid fish ecomorphs in a small (700m diameter) isolated crater lake in Tanzania. The ecomorphs differ in depth preference, male breeding color, body shape, diet and trophic morphology. With whole genome sequences of 146 fish, we identify 98 clearly demarcated genomic ‘islands’ of high differentiation and demonstrate association of genotypes across these islands to divergent mate preferences. The islands contain candidate adaptive genes enriched for functions in sensory perception (including rhodopsin and other twilight vision associated genes), hormone signaling and morphogenesis. Our study suggests mechanisms and genomic regions that may play a role in the closely related mega-radiation of Lake Malawi.The work was funded by Royal Society-Leverhulme Trust Africa Awards AA100023 and AA130107 (M.J.G., B.P.N. and G.F.T.), a Wellcome Trust PhD studentship grant 097677/Z/11/Z (M.M.), Wellcome Trust grant WT098051 (S.S. and R.D.), Wellcome Trust and Cancer Research UK core support and a Wellcome Trust Senior Investigator Award (E.A.M.), a Leverhulme Trust Research Fellowship RF-2014-686 (M.J.G.), a University of Bristol Research Committee award (M.G.), a Bangor University Anniversary PhD studentship (to A.M.T.) and a Fisheries Society of the British Isles award (G.F.T.). Raw sequencing reads are in the SRA nucleotide archive: RAD sequencing (BioProject: PRJNA286304; accessions SAMN03768857 to SAMN03768912) and whole genome sequencing (BioProject PRJEB1254: sample accessions listed in Table S16). The RAD based phylogeny and alignments have been deposited in TreeBase (TB2:S18241). Whole genome variant calls in the VCF format, phylogenetic trees, and primer sequences for Sequenom genotyping are available from the Dryad Digital Repository (http://dx.doi.org/10.5061/dryad.770mc). RD declares his interests as a founder and non-executive director of Congenica Ltd., that he owns stock in Illumina from previous consulting, and is a scientific advisory board member of Dovetail Inc. We thank R. Schley for generating pharyngeal jaw data; S. Mzighani, J. Kihedu and staff of the Tanzanian Fisheries Research Institute for logistical support; A. Smith, H. Sungani, A. Shechonge, P. Parsons, J. Swanstrom, G. Cooke and J. Bridle for contributions to sampling and aquarium maintenance, the Sanger Institute sequencing core for DNA sequencing and Dr. H. Imai (Kyoto University) for the use of spectrometer in his laboratory.This is the author accepted manuscript. The final version is available from AAAS via http://dx.doi.org/10.1126/science.aac992

    Active growth signaling promotes senescence and cancer cell sensitivity to CDK7 inhibition

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    Tumor growth is driven by continued cellular growth and proliferation. Cyclin-dependent kinase 7’s (CDK7) role in activating mitotic CDKs and global gene expression makes it therefore an attractive target for cancer therapies. However, what makes cancer cells particularly sensitive to CDK7 inhibition (CDK7i) remains unclear. Here, we address this question. We show that CDK7i, by samuraciclib, induces a permanent cell-cycle exit, known as senescence, without promoting DNA damage signaling or cell death. A chemogenetic genome-wide CRISPR knockout screen identified that active mTOR (mammalian target of rapamycin) signaling promotes samuraciclib-induced senescence. mTOR inhibition decreases samuraciclib sensitivity, and increased mTOR-dependent growth signaling correlates with sensitivity in cancer cell lines. Reverting a growth-promoting mutation in PIK3CA to wild type decreases sensitivity to CDK7i. Our work establishes that enhanced growth alone promotes CDK7i sensitivity, providing an explanation for why some cancers are more sensitive to CDK inhibition than normally growing cells

    Mapping epigenetic divergence in the massive radiation of Lake Malawi cichlid fishes.

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    Epigenetic variation modulates gene expression and can be heritable. However, knowledge of the contribution of epigenetic divergence to adaptive diversification in nature remains limited. The massive evolutionary radiation of Lake Malawi cichlid fishes displaying extensive phenotypic diversity despite extremely low sequence divergence is an excellent system to study the epigenomic contribution to adaptation. Here, we present a comparative genome-wide methylome and transcriptome study, focussing on liver and muscle tissues in phenotypically divergent cichlid species. In both tissues we find substantial methylome divergence among species. Differentially methylated regions (DMR), enriched in evolutionary young transposons, are associated with transcription changes of ecologically-relevant genes related to energy expenditure and lipid metabolism, pointing to a link between dietary ecology and methylome divergence. Unexpectedly, half of all species-specific DMRs are shared across tissues and are enriched in developmental genes, likely reflecting distinct epigenetic developmental programmes. Our study reveals substantial methylome divergence in closely-related cichlid fishes and represents a resource to study the role of epigenetics in species diversification
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