98 research outputs found

    Dual regulation by microRNA-200b-3p and microRNA-200b-5p in the inhibition of epithelial-to-mesenchymal transition in triple-negative breast cancer

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    Epithelial to mesenchymal transition (EMT) involves loss of an epithelial phenotype and activation of a mesenchymal one. Enhanced expression of genes associated with a mesenchymal transition includes ZEB1/2, TWIST, and FOXC1. miRNAs are known regulators of gene expression and altered miRNA expression is known to enhance EMT in breast cancer. Here we demonstrate that the tumor suppressive miRNA family, miR-200, is not expressed in triple negative breast cancer (TNBC) cell lines and that miR-200b-3p over-expression represses EMT, which is evident through decreased migration and increased CDH1 expression. Despite the loss of migratory capacity following re-expression of miR-200b-3p, no subsequent loss of the conventional miR-200 family targets and EMT markers ZEB1/2 was observed. Next generation RNA-sequencing analysis showed that enhanced expression of pri-miR-200b lead to ectopic expression of both miR-200b-3p and miR-200b-5p with multiple isomiRs expressed for each of these miRNAs. Furthermore, miR-200b-5p was expressed in the receptor positive, epithelial breast cancer cell lines but not in the TNBC (mesenchymal) cell lines. In addition, a compensatory mechanism for miR-200b-3p/200b-5p targeting, where both miRNAs target the RHOGDI pathway leading to non-canonical repression of EMT, was demonstrated. Collectively, these data are the first to demonstrate dual targeting by miR-200b-3p and miR-200b-5p and a previously undescribed role for microRNA processing and strand expression in EMT and TNBC, the most aggressive breast cancer subtype

    Arthropod associates of Kenyan buffelgrass (Cenchrus ciliaris): a field survey for biological control candidates of a globally important invasive grass

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    Invasive species are the second largest contributor to biodiversity loss and drivers of ecosystem change. Buffelgrass is a C4, perennial grass native to Africa and Asia that was widely introduced across tropical and subtropical rangelands as livestock forage. Buffelgrass reduces native biodiversity and ecosystem stability in its introduced range when it escapes livestock pastures. Understanding the ecology of insects associated with buffelgrass in its native range may provide an understanding of invasion processes and biological control opportunities where buffelgrass has become an invasive challenge. Here, we present the results of a six-year survey of herbivorous arthropods of a native buffelgrass population from Kenya. Buffelgrass was examined for externally and internally feeding insects of vegetative and reproductive tissues. We also categorised buffelgrass detritivores and parasitoids that may use buffelgrass herbivores as hosts. The samples were photographed and Sanger sequenced to identify them to the lowest possible taxonomic ranking. We collected information on sample abundances, phenologies, tissues consumed, and putative diet breadths. We identified 25 morphospecies representing seven orders and 16 families. The putative host plant specialisation was as high as 67% for Diptera. Phenological variation in herbivore presence correlated with seasonal rainfall and provided a guide for when to conduct follow-up biological control agent searches. The most abundant herbivore was a gall midge (Diptera: Cecidomyiidae) that inhabits buffelgrass culms. Additional research should focus on bringing this species into containment where host choice trials can be conducted to determine if it is truly monophagous and assess its impact on buffelgrass growth

    Systematic reduction of natural enemies and competition across variable precipitation approximates buffelgrass invasiveness (Cenchrus ciliaris) in its native range

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    Invasive grasses cause devastating losses to biodiversity and ecosystem function directly and indirectly by altering ecosystem processes. Escape from natural enemies, plant–plant competition, and variable resource availability provide frameworks for understanding invasion. However, we lack a clear understanding of how natural stressors interact in their native range to regulate invasiveness. In this study, we reduced diverse guilds of natural enemies and plant competitors of the highly invasive buffelgrass across a precipitation gradient throughout major climatic shifts in Laikipia, Kenya. To do this, we used a long-term ungulate exclosure experiment design across a precipitation gradient with nested treatments that (1) reduced plant competition through clipping, (2) reduced insects through systemic insecticide, and (3) reduced fungal associates through fungicide application. Additionally, we measured the interaction of ungulates on two stem-boring insect species feeding on buffelgrass. Finally, we measured a multiyear smut fungus outbreak. Our findings suggest that buffelgrass exhibits invasive qualities when released from a diverse group of natural stressors in its native range. We show natural enemies interact with precipitation to alter buffelgrass productivity patterns. In addition, interspecific plant competition decreased the basal area of buffelgrass, suggesting that biotic resistance mediates buffelgrass dominance in the home range. Surprisingly, systemic insecticides and fungicides did not impact buffelgrass production or reproduction, perhaps because other guilds filled the niche space in these highly diverse systems. For example, in the absence of ungulates, we showed an increase in host-specific stem-galling insects, where these insects compensated for reduced ungulate use. Finally, we documented a smut outbreak in 2020 and 2021, corresponding to highly variable precipitation patterns caused by a shifting Indian Ocean Dipole. In conclusion, we observed how reducing natural enemies and competitors and certain interactions increased properties related to buffelgrass invasiveness

    Systematic reduction of natural enemies and competition across variable precipitation approximates buffelgrass invasiveness ( Cenchrus ciliaris ) in its native range

    Get PDF
    Invasive grasses cause devastating losses to biodiversity and ecosystem function directly and indirectly by altering ecosystem processes. Escape from natural enemies, plant–plant competition, and variable resource availability provide frameworks for understanding invasion. However, we lack a clear understanding of how natural stressors interact in their native range to regulate invasiveness. In this study, we reduced diverse guilds of natural enemies and plant competitors of the highly invasive buffelgrass across a precipitation gradient throughout major climatic shifts in Laikipia, Kenya. To do this, we used a long‐term ungulate exclosure experiment design across a precipitation gradient with nested treatments that (1) reduced plant competition through clipping, (2) reduced insects through systemic insecticide, and (3) reduced fungal associates through fungicide application. Additionally, we measured the interaction of ungulates on two stem‐boring insect species feeding on buffelgrass. Finally, we measured a multiyear smut fungus outbreak. Our findings suggest that buffelgrass exhibits invasive qualities when released from a diverse group of natural stressors in its native range. We show natural enemies interact with precipitation to alter buffelgrass productivity patterns. In addition, interspecific plant competition decreased the basal area of buffelgrass, suggesting that biotic resistance mediates buffelgrass dominance in the home range. Surprisingly, systemic insecticides and fungicides did not impact buffelgrass production or reproduction, perhaps because other guilds filled the niche space in these highly diverse systems. For example, in the absence of ungulates, we showed an increase in host‐specific stem‐galling insects, where these insects compensated for reduced ungulate use. Finally, we documented a smut outbreak in 2020 and 2021, corresponding to highly variable precipitation patterns caused by a shifting Indian Ocean Dipole. In conclusion, we observed how reducing natural enemies and competitors and certain interactions increased properties related to buffelgrass invasiveness

    Forecasting the spread of raccoon rabies using a purpose-specific group decisionmaking process

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    The Centers for Disease Control (CDC) and USDA Wildlife Services (WS) have been involved in an oral rabies vaccination (ORV) program for raccoons (Procyon lotor) that has slowed the westward spread of raccoon rabies. The objective of this study was to forecast the spread of the disease if an ORV zone was not maintained. A group decision-making process was designed to address the forecasting problem and was implemented using a group of 15 experts and 4 support personnel at a meeting at the USDA National Wildlife Research Center. Ten expansion regions were constructed that described the spread of disease at 2-year intervals. This forecast may provide for more accurate cost-benefit analysis of the ORV barrier

    Prevalence Estimates of Health Risk Behaviors of Immigrant Latino Men Who Have Sex With Men

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    Little is known about the health status of rural immigrant Latino men who have sex with men (MSM). These MSM comprise a subpopulation that tends to remain “hidden” from both researchers and practitioners. This study was designed to estimate the prevalence of tobacco, alcohol, and drug use, and sexual risk behaviors of Latino MSM living in rural North Carolina

    A Randomized Controlled Trial of a Culturally Congruent Intervention to Increase Condom Use and HIV Testing Among Heterosexually Active Immigrant Latino Men

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    This randomized controlled trial tested the efficacy of an HIV prevention intervention to increase condom use and HIV testing among Spanish-speaking, heterosexually active immigrant Latino men. A community-based participatory research partnership developed the intervention and selected the study design. Following baseline data collection, 142 immigrant Latino men were randomized to the HIV prevention intervention or the cancer education intervention. Three-month follow-up data were collected from 139 participants, for a 98% retention rate. Mean age of participants was 31.6 years and 60% reported being from Mexico. Adjusting for baseline behaviors, relative to their peers in the cancer education comparison, participants in the HIV prevention intervention were more likely to report consistent condom use and receiving an HIV test. Community-based interventions for immigrant Latino men that are built on state of the art prevention science and developed in partnership with community members can greatly enhance preventive behaviors and may reduce HIV infection

    Aldehyde dehydrogenase inhibition as a pathogenic mechanism in Parkinson disease

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    Parkinson disease (PD) is a neurodegenerative disorder particularly characterized by the loss of dopaminergic neurons in the substantia nigra. Pesticide exposure has been associated with PD occurrence, and we previously reported that the fungicide benomyl interferes with several cellular processes potentially relevant to PD pathogenesis. Here we propose that benomyl, via its bioactivated thiocarbamate sulfoxide metabolite, inhibits aldehyde dehydrogenase (ALDH), leading to accumulation of the reactive dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL), preferential degeneration of dopaminergic neurons, and development of PD. This hypothesis is supported by multiple lines of evidence. (i) We previously showed in mice the metabolism of benomyl to S-methyl N-butylthiocarbamate sulfoxide, which inhibits ALDH at nanomolar levels. We report here that benomyl exposure in primary mesencephalic neurons (ii) inhibits ALDH and (iii) alters dopamine homeostasis. It induces selective dopaminergic neuronal damage (iv) in vitro in primary mesencephalic cultures and (v) in vivo in a zebrafish system. (vi) In vitro cell loss was attenuated by reducing DOPAL formation. (vii) In our epidemiology study, higher exposure to benomyl was associated with increased PD risk. This ALDH model for PD etiology may help explain the selective vulnerability of dopaminergic neurons in PD and provide a potential mechanism through which environmental toxicants contribute to PD pathogenesis

    A CBPR Partnership Increases HIV Testing Among Men Who Have Sex With Men (MSM): Outcome Findings From a Pilot Test of the CyBER/testing Internet Intervention

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    The Internet has emerged as an important tool for the delivery of health promotion and disease prevention interventions. Our community-based participatory research (CBPR) partnership developed and piloted CyBER/testing, a culturally congruent intervention designed to promote HIV testing among men who have sex with men (MSM) within existing Internet chat rooms. Using a quasi-experimental, single-group study design, cross-sectional data were collected from chat room participants, known as “chatters,” at pretest (n=346) and post-test (n=315). Extant profile data also were collected to describe the demographics of the online population. The intervention significantly increased self-reported HIV testing among chatters overall, increasing rates from 44.5% at pretest to nearly 60% at post-test (p<.001). Furthermore, chatters who reported having both male and female sexual partners had nearly 6 times the odds of reporting HIV testing at post-test. Findings suggest that chat room-based HIV testing intervention may increase testing among MSM who may be difficult to reach in traditional physical spaces

    Integrating data types to estimate spatial patterns of avian migration across the Western Hemisphere

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    For many avian species, spatial migration patterns remain largely undescribed, especially across hemispheric extents. Recent advancements in tracking technologies and high-resolution species distribution models (i.e., eBird Status and Trends products) provide new insights into migratory bird movements and offer a promising opportunity for integrating independent data sources to describe avian migration. Here, we present a three-stage modeling framework for estimating spatial patterns of avian migration. First, we integrate tracking and band re-encounter data to quantify migratory connectivity, defined as the relative proportions of individuals migrating between breeding and nonbreeding regions. Next, we use estimated connectivity proportions along with eBird occurrence probabilities to produce probabilistic least-cost path (LCP) indices. In a final step, we use generalized additive mixed models (GAMMs) both to evaluate the ability of LCP indices to accurately predict (i.e., as a covariate) observed locations derived from tracking and band re-encounter data sets versus pseudo-absence locations during migratory periods and to create a fully integrated (i.e., eBird occurrence, LCP, and tracking/band re-encounter data) spatial prediction index for mapping species-specific seasonal migrations. To illustrate this approach, we apply this framework to describe seasonal migrations of 12 bird species across the Western Hemisphere during pre- and postbreeding migratory periods (i.e., spring and fall, respectively). We found that including LCP indices with eBird occurrence in GAMMs generally improved the ability to accurately predict observed migratory locations compared to models with eBird occurrence alone. Using three performance metrics, the eBird + LCP model demonstrated equivalent or superior fit relative to the eBird-only model for 22 of 24 species–season GAMMs. In particular, the integrated index filled in spatial gaps for species with over-water movements and those that migrated over land where there were few eBird sightings and, thus, low predictive ability of eBird occurrence probabilities (e.g., Amazonian rainforest in South America). This methodology of combining individual-based seasonal movement data with temporally dynamic species distribution models provides a comprehensive approach to integrating multiple data types to describe broad-scale spatial patterns of animal movement. Further development and customization of this approach will continue to advance knowledge about the full annual cycle and conservation of migratory birds
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