66 research outputs found
Effects of Aprons on Pitfall Trap Catches of Carabid Beetles in Forests and Fields
This study compared the efficacy of three types of pitfall traps in four forest and two field habitats. Two traps had aprons and one did not. The two apron traps were the same except for a gap between the trap and the plywood-apron, allowing captures from above or below. Traps were placed in a split-plot design and had three replicates of the three trap types per habitat. The traps were emptied each week from May to September. ANOVA\u27s were performed on 12 trapped species separately over habitats, weeks, and the in- teractions between them. The nonapron trap captured over 40% more individuals than either apron trap, though apron traps tended to be more effective in fields for species found in both habitats. Habitat-trap interactions were only significant in two species. Trap-week interactions were significant in four species
Orchard: building large cancer phylogenies using stochastic combinatorial search
Phylogenies depicting the evolutionary history of genetically heterogeneous
subpopulations of cells from the same cancer i.e., cancer phylogenies, provide
useful insights about cancer development and inform treatment. Cancer
phylogenies can be reconstructed using data obtained from bulk DNA sequencing
of multiple tissue samples from the same cancer. We introduce Orchard, a fast
algorithm that reconstructs cancer phylogenies using point mutations detected
in bulk DNA sequencing data. Orchard constructs cancer phylogenies
progressively, one point mutation at a time, ultimately sampling complete
phylogenies from a posterior distribution implied by the bulk DNA data. Orchard
reconstructs more plausible phylogenies than state-of-the-art cancer phylogeny
reconstruction methods on 90 simulated cancers and 14 B-progenitor acute
lymphoblastic leukemias (B-ALLs). These results demonstrate that Orchard
accurately reconstructs cancer phylogenies with up to 300 mutations. We then
introduce a simple graph based clustering algorithm that uses a reconstructed
phylogeny to infer unique groups of mutations i.e., mutation clusters, that
characterize the genetic differences between cancer cell populations, and show
that this approach is competitive with state-of-the-art mutation clustering
methods
Role of Ucp1 enhancer methylation and chromatin remodelling in the control of Ucp1 expression in murine adipose tissue
Aims/hypothesis
Increasing the expression of the brown adipose tissue-specific gene uncoupling protein-1 (Ucp1) is a potential target for treating obesity. We investigated the role of DNA methylation and histone modification in Ucp1 expression in adipose cell lines and ex vivo murine adipose tissues.
Methods
Methylation state of the Ucp1 enhancer was studied using bisulphite mapping in murine adipose cell lines, and tissue taken from cold-stressed mice, coupled with functional assays of the effects of methylation and demethylation of the Ucp1 promoter on gene expression and nuclear protein binding.
Results
We show that demethylation of the Ucp1 promoter by 5-aza-deoxycytidine increases Ucp1 expression while methylation of Ucp1 promoter–reporter constructs decreases expression. Brown adipose tissue-specific Ucp1 expression is associated with decreased CpG dinucleotide methylation of the Ucp1 enhancer. The lowest CpG dinucleotide methylation state was found in two cyclic AMP response elements (CRE3, CRE2) in the Ucp1 promoter and methylation of the CpG in CRE2, but not CRE3 decreased nuclear protein binding. Chromatin immunoprecipitation assays revealed the presence of the silencing DiMethH3K9 modification on the Ucp1 enhancer in white adipose tissue and the appearance of the active TriMethH3K4 mark at the Ucp1 promoter in brown adipose tissue in response to a cold environment.
Conclusions/interpretation
The results demonstrate that CpG dinucleotide methylation of the Ucp1 enhancer exhibits tissue-specific patterns in murine tissue and cell lines and suggest that adipose tissue-specific Ucp1 expression involves demethylation of CpG dinucleotides found in regulatory CREs in the Ucp1 enhancer, as well as modification of histone tails
Urochordate Histoincompatible Interactions Activate Vertebrate-Like Coagulation System Components
The colonial ascidian Botryllus schlosseri expresses a unique allorecognition system. When two histoincompatible Botryllus colonies come into direct contact, they develop an inflammatory-like rejection response. A surprising high number of vertebrates' coagulation genes and coagulation-related domains were disclosed in a cDNA library of differentially expressed sequence tags (ESTs), prepared for this allorejection process. Serine proteases, especially from the trypsin family, were highly represented among Botryllus library ortholgues and its “molecular function” gene ontology analysis. These, together with the built-up clot-like lesions in the interaction area, led us to further test whether a vertebrate-like clotting system participates in Botryllus innate immunity. Three morphologically distinct clot types (points of rejection; POR) were followed. We demonstrated the specific expression of nine coagulation orthologue transcripts in Botryllus rejection processes and effects of the anti-coagulant heparin on POR formation and heartbeats. In situ hybridization of fibrinogen and von Willebrand factor orthologues elucidated enhanced expression patterns specific to histoincompatible reactions as well as common expressions not augmented by innate immunity. Immunohistochemistry for fibrinogen revealed, in naïve and immune challenged colonies alike, specific antibody binding to a small population of Botryllus compartment cells. Altogether, molecular, physiological and morphological outcomes suggest the involvement of vertebrates-like coagulation elements in urochordate immunity, not assigned with vasculature injury
Parent-Of-Origin Effects in Autism Identified through Genome-Wide Linkage Analysis of 16,000 SNPs
Autism is a common heritable neurodevelopmental disorder with complex etiology. Several genome-wide linkage and association scans have been carried out to identify regions harboring genes related to autism or autism spectrum disorders, with mixed results. Given the overlap in autism features with genetic abnormalities known to be associated with imprinting, one possible reason for lack of consistency would be the influence of parent-of-origin effects that may mask the ability to detect linkage and association.We have performed a genome-wide linkage scan that accounts for potential parent-of-origin effects using 16,311 SNPs among families from the Autism Genetic Resource Exchange (AGRE) and the National Institute of Mental Health (NIMH) autism repository. We report parametric (GH, Genehunter) and allele-sharing linkage (Aspex) results using a broad spectrum disorder case definition. Paternal-origin genome-wide statistically significant linkage was observed on chromosomes 4 (LOD(GH) = 3.79, empirical p<0.005 and LOD(Aspex) = 2.96, p = 0.008), 15 (LOD(GH) = 3.09, empirical p<0.005 and LOD(Aspex) = 3.62, empirical p = 0.003) and 20 (LOD(GH) = 3.36, empirical p<0.005 and LOD(Aspex) = 3.38, empirical p = 0.006).These regions may harbor imprinted sites associated with the development of autism and offer fruitful domains for molecular investigation into the role of epigenetic mechanisms in autism
Compartment-Restricted Biotinylation Reveals Novel Features of Prion Protein Metabolism in Vivo
A selective tagging method for detecting minor alternatively-localized populations of a protein is used to study a disease-associated transmembrane form of prion protein. The analysis reveals key features of transmembrane prion protein metabolism and one way this is altered by human disease-causing mutants
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