140 research outputs found

    Beyond the standard seesaw: neutrino masses from Kahler operators and broken supersymmetry

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    We investigate supersymmetric scenarios in which neutrino masses are generated by effective d=6 operators in the Kahler potential, rather than by the standard d=5 superpotential operator. First, we discuss some general features of such effective operators, also including SUSY-breaking insertions, and compute the relevant renormalization group equations. Contributions to neutrino masses arise at low energy both at the tree level and through finite threshold corrections. In the second part we present simple explicit realizations in which those Kahler operators arise by integrating out heavy SU(2)_W triplets, as in the type II seesaw. Distinct scenarios emerge, depending on the mechanism and the scale of SUSY-breaking mediation. In particular, we propose an appealing and economical picture in which the heavy seesaw mediators are also messengers of SUSY breaking. In this case, strong correlations exist among neutrino parameters, sparticle and Higgs masses, as well as lepton flavour violating processes. Hence, this scenario can be tested at high-energy colliders, such as the LHC, and at lower energy experiments that measure neutrino parameters or search for rare lepton decays.Comment: LaTeX, 34 pages; some corrections in Section

    Sources of variation in cuticular hydrocarbons in the ant formica exsecta

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    Phenotypic variation arises from interactions between genotype and environment, although how variation is produced and then maintained remains unclear. The discovery of the nest-mate recognition system in Formica exsecta ants has allowed phenotypic variation in chemical profiles to be quantified across a natural population of 83 colonies. We investigated if this variation was correlated or not with intrinsic (genetic relatedness), extrinsic (location, light, temperature) or social (queen number) factors. (Z)-9-Alkenes and n-alkanes showed different patterns of variance: island (location) explained only 0.2% of the variation in (Z)-9-alkenes, but 21¬–29% in n-alkanes, whereas colony of origin explained 96% and 45–49% of the variation in (Z)-9-alkenes and n-alkanes, respectively. By contrast, within-colony variance of (Z)-9-alkenes was 4%, and 23–34% in n-alkanes, supporting the function of the former as recognition cues. (Z)-9-Alkene and n-alkane profiles were correlated with the genetic distance between colonies. Only n-alkane profiles diverged with increasing spatial distance. Sampling year explained a small (5%), but significant, amount of the variation in the (Z)-9-alkenes, but there was no consistent directional trend. Polygynous colonies and populous monogynous colonies were dominated by a rich C23:1 profile. We found no associations between worker size, mound exposure, or humidity, although effect sizes for the latter two factors were considerable. The results support the conjecture that genetic factors are the most likely source of between-colony variation in cuticular hydrocarbons

    Oncogene Activation Induces Metabolic Transformation Resulting in Insulin-Independence in Human Breast Cancer Cells

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    Normal breast epithelial cells require insulin and EGF for growth in serum-free media. We previously demonstrated that over expression of breast cancer oncogenes transforms MCF10A cells to an insulin-independent phenotype. Additionally, most breast cancer cell lines are insulin-independent for growth. In this study, we investigated the mechanism by which oncogene over expression transforms MCF10A cells to an insulin-independent phenotype. Analysis of the effects of various concentrations of insulin and/or IGF-I on proliferation of MCF10A cells demonstrated that some of the effects of insulin were independent from those of IGF-I, suggesting that oncogene over expression drives a true insulin-independent proliferative phenotype. To test this hypothesis, we examined metabolic functions of insulin signaling in insulin-dependent and insulin-independent cells. HER2 over expression in MCF10A cells resulted in glucose uptake in the absence of insulin at a rate equal to insulin-induced glucose uptake in non-transduced cells. We found that a diverse set of oncogenes induced the same result. To gain insight into how HER2 oncogene signaling affected increased insulin-independent glucose uptake we compared HER2-regulated gene expression signatures in MCF10A and HER2 over expressing MCF10A cells by differential analysis of time series gene expression data from cells treated with a HER2 inhibitor. This analysis identified genes specifically regulated by the HER2 oncogene, including VAMP8 and PHGDH, which have known functions in glucose uptake and processing of glycolytic intermediates, respectively. Moreover, these genes specifically implicated in HER2 oncogene-driven transformation are commonly altered in human breast cancer cells. These results highlight the diversity of oncogene effects on cell regulatory pathways and the importance of oncogene-driven metabolic transformation in breast cancer

    Altered striatal endocannabinoid signaling in a transgenic mouse model of spinocerebellar ataxia type-3

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    Spinocerebellar ataxia type-3 (SCA-3) is the most prevalent autosomal dominant inherited ataxia. We recently found that the endocannabinoid system is altered in the post-mortem cerebellum of SCA-3 patients, and similar results were also found in the cerebellar and brainstem nuclei of a SCA-3 transgenic mouse model. Given that the neuropathology of SCA-3 is not restricted to these two brain regions but rather, it is also evident in other structures (e.g., the basal ganglia), we studied the possible changes to endocannabinoid signaling in the striatum of these transgenic mice. SCA-3 mutant mice suffer defects in motor coordination, balance and they have an abnormal gait, reflecting a cerebellar/brainstem neuropathology. However, they also show dystonia-like behavior (limb clasping) that may be related to the malfunction/deterioration of specific neurons in the striatum. Indeed, we found a loss of striatal projecting neurons in SCA-3 mutant mice, accompanied by a reduction in glial glutamate transporters that could potentially aggravate excitotoxic damage. In terms of endocannabinoid signaling, no changes in CB2 receptors were evident, yet an important reduction in CB1 receptors was detected by qPCR and immunostaining. The reduction in CB1 receptors was presumed to occur in striatal afferent and efferent neurons, also potentially aggravating excitotoxicity. We also measured the endocannabinoid lipids in the striatum and despite a marked increase in the FAAH enzyme in this area, no overall changes in these lipids were found. Collectively, these studies confirm that the striatal endocannabinoid system is altered in SCA-3 mutant mice, adding to the equivalent changes found in other strongly affected CNS structures in this type of ataxia (i.e.: the cerebellum and brainstem). These data open the way to search for drugs that might correct these changes.Funding: This study has been supported: (i) by MICINN (SAF2009-11847 and SAF2015-68580-C2-1-R), CIBERNED (CB06/05/0089) and “Fundación Eugenio Rodríguez Pascual”, to JFR; (ii) by the Research and Education Component of the Advancing a Healthier Wisconsin Endowment at the Medical College of Wisconsin, to CJH; and (iii) by Fundação para a Ciência e Tecnologia through the project POCI-01-0145-FEDER-016818 (PTDC/NEU-NMC/3648/2014) and co-financed by the Portuguese North Regional Operational Program (ON.2 – O Novo Norte) under the National Strategic Reference Framework (QREN), through the European Regional Development Fund (FEDER), to PM. Carmen Rodríguez-Cueto was a predoctoral fellow supported by FPI Program-Ministry of Science. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.info:eu-repo/semantics/publishedVersio

    Rapid Acoustic Survey for Biodiversity Appraisal

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    Biodiversity assessment remains one of the most difficult challenges encountered by ecologists and conservation biologists. This task is becoming even more urgent with the current increase of habitat loss. Many methods–from rapid biodiversity assessments (RBA) to all-taxa biodiversity inventories (ATBI)–have been developed for decades to estimate local species richness. However, these methods are costly and invasive. Several animals–birds, mammals, amphibians, fishes and arthropods–produce sounds when moving, communicating or sensing their environment. Here we propose a new concept and method to describe biodiversity. We suggest to forego species or morphospecies identification used by ATBI and RBA respectively but rather to tackle the problem at another evolutionary unit, the community level. We also propose that a part of diversity can be estimated and compared through a rapid acoustic analysis of the sound produced by animal communities. We produced α and β diversity indexes that we first tested with 540 simulated acoustic communities. The α index, which measures acoustic entropy, shows a logarithmic correlation with the number of species within the acoustic community. The β index, which estimates both temporal and spectral dissimilarities, is linearly linked to the number of unshared species between acoustic communities. We then applied both indexes to two closely spaced Tanzanian dry lowland coastal forests. Indexes reveal for this small sample a lower acoustic diversity for the most disturbed forest and acoustic dissimilarities between the two forests suggest that degradation could have significantly decreased and modified community composition. Our results demonstrate for the first time that an indicator of biological diversity can be reliably obtained in a non-invasive way and with a limited sampling effort. This new approach may facilitate the appraisal of animal diversity at large spatial and temporal scales

    Two Host Factors Regulate Persistence of H7a-Specific T Cells Injected in Tumor-Bearing Mice

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    BACKGROUND: Injection of CD8 T cells primed against immunodominant minor histocompatibility antigens (MiHA) such as H7(a) can eradicate leukemia and solid tumors. To understand why MiHA-targeted T cells have such a potent antitumor effect it is essential to evaluate their in vivo behavior. In the present work, we therefore addressed two specific questions: what is the proliferative dynamics of H7(a)-specifc T cells in tumors, and do H7(a)-specific T cells persist long-term after adoptive transfer? METHODOLOGY/PRINCIPAL FINDINGS: By day 3 after adoptive transfer, we observed a selective infiltration of melanomas by anti-H7(a) T cells. Over the next five days, anti-H7(a) T cells expanded massively in the tumor but not in the spleen. Thus, by day 8 after injection, anti-H7(a) T cells in the tumor had undergone more cell divisions than those in the spleen. These data strongly suggest that anti-H7(a) T cells proliferate preferentially and extensively in the tumors. We also found that two host factors regulated long-term persistence of anti-H7(a) memory T cells: thymic function and expression of H7(a) by host cells. On day 100, anti-H7(a) memory T cells were abundant in euthymic H7(a)-negative (B10.H7(b)) mice, present in low numbers in thymectomized H7(a)-positive (B10) hosts, and undetectable in euthymic H7(a)-positive recipients. CONCLUSIONS/SIGNIFICANCE: Although in general the tumor environment is not propitious to T-cell invasion and expansion, the present work shows that this limitation may be overcome by adoptive transfer of primed CD8 T cells targeted to an immunodominant MiHA (here H7(a)). At least in some cases, prolonged persistence of adoptively transferred T cells may be valuable for prevention of late cancer relapse in adoptive hosts. Our findings therefore suggest that it may be advantageous to target MiHAs with a restricted tissue distribution in order to promote persistence of memory T cells and thereby minimize the risk of cancer recurrence

    Complete Genome Sequence of Crohn's Disease-Associated Adherent-Invasive E. coli Strain LF82

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    International audienceBACKGROUND: Ileal lesions of Crohn's disease (CD) patients are abnormally colonized by pathogenic adherent-invasive Escherichia coli (AIEC) able to invade and to replicate within intestinal epithelial cells and macrophages. PRINCIPAL FINDINGS: We report here the complete genome sequence of E. coli LF82, the reference strain of adherent-invasive E. coli associated with ileal Crohn's disease. The LF82 genome of 4,881,487 bp total size contains a circular chromosome with a size of 4,773,108 bp and a plasmid of 108,379 bp. The analysis of predicted coding sequences (CDSs) within the LF82 flexible genome indicated that this genome is close to the avian pathogenic strain APEC_01, meningitis-associated strain S88 and urinary-isolated strain UTI89 with regards to flexible genome and single nucleotide polymorphisms in various virulence factors. Interestingly, we observed that strains LF82 and UTI89 adhered at a similar level to Intestine-407 cells and that like LF82, APEC_01 and UTI89 were highly invasive. However, A1EC strain LF82 had an intermediate killer phenotype compared to APEC-01 and UTI89 and the LF82 genome does not harbour most of specific virulence genes from ExPEC. LF82 genome has evolved from those of ExPEC B2 strains by the acquisition of Salmonella and Yersinia isolated or clustered genes or CDSs located on pLF82 plasmid and at various loci on the chromosome. CONCLUSION: LF82 genome analysis indicated that a number of genes, gene clusters and pathoadaptative mutations which have been acquired may play a role in virulence of AIEC strain LF82

    Identification of co-expression gene networks, regulatory genes and pathways for obesity based on adipose tissue RNA Sequencing in a porcine model

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    Background: Obesity is a complex metabolic condition in strong association with various diseases, like type 2 diabetes, resulting in major public health and economic implications. Obesity is the result of environmental and genetic factors and their interactions, including genome-wide genetic interactions. Identification of co-expressed and regulatory genes in RNA extracted from relevant tissues representing lean and obese individuals provides an entry point for the identification of genes and pathways of importance to the development of obesity. The pig, an omnivorous animal, is an excellent model for human obesity, offering the possibility to study in-depth organ-level transcriptomic regulations of obesity, unfeasible in humans. Our aim was to reveal adipose tissue co-expression networks, pathways and transcriptional regulations of obesity using RNA Sequencing based systems biology approaches in a porcine model. Methods: We selected 36 animals for RNA Sequencing from a previously created F2 pig population representing three extreme groups based on their predicted genetic risks for obesity. We applied Weighted Gene Co-expression Network Analysis (WGCNA) to detect clusters of highly co-expressed genes (modules). Additionally, regulator genes were detected using Lemon-Tree algorithms. Results: WGCNA revealed five modules which were strongly correlated with at least one obesity-related phenotype (correlations ranging from -0.54 to 0.72, P <0.001). Functional annotation identified pathways enlightening the association between obesity and other diseases, like osteoporosis (osteoclast differentiation, P = 1.4E(-7)), and immune-related complications (e. g. Natural killer cell mediated cytotoxity, P = 3.8E(-5); B cell receptor signaling pathway, P = 7.2E(-5)). Lemon-Tree identified three potential regulator genes, using confident scores, for the WGCNA module which was associated with osteoclast differentiation: CCR1, MSR1 and SI1 (probability scores respectively 95.30, 62.28, and 34.58). Moreover, detection of differentially connected genes identified various genes previously identified to be associated with obesity in humans and rodents, e.g. CSF1R and MARC2. Conclusions: To our knowledge, this is the first study to apply systems biology approaches using porcine adipose tissue RNA-Sequencing data in a genetically characterized porcine model for obesity. We revealed complex networks, pathways, candidate and regulatory genes related to obesity, confirming the complexity of obesity and its association with immune-related disorders and osteoporosis
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