384 research outputs found

    Efficient targeted mutagenesis in the monarch butterfly using zinc finger nucleases

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    The development of reverse-genetic tools in non-model insect species with distinct biology is critical to establish them as viable model systems. The eastern North American monarch butterfly (Danaus plexippus), whose genome is sequenced, has emerged as a model to study animal clocks, navigational mechanisms and the genetic basis of long-distance migration. Here, we developed a highly efficient gene-targeting approach in the monarch using zinc-finger nucleases (ZFNs), engineered nucleases that generate mutations at targeted genomic sequences. We focused our ZFN approach on targeting the type 2 vertebrate-like cryptochrome gene of the monarch (designated cry2), which encodes a putative transcriptional repressor of the monarch circadian clockwork. Co-injections of mRNAs encoding ZFNs targeting the second exon of monarch cry2 into one nucleus stage embryos led to high frequency non-homologous end-joining-mediated, mutagenic lesions in the germline (up to 50%). Heritable ZFN-induced lesions in two independent lines produced truncated, nonfunctional CRY2 proteins, resulting in the in vivo disruption of circadian behavior and the molecular clock mechanism. Our work genetically defines CRY2 as an essential transcriptional repressor of the monarch circadian clock and provides a proof of concept for the use of ZFNs for manipulating genes in the monarch butterfly genome. Importantly, this approach could be used in other lepidopterans and non-model insects, thus opening new avenues to decipher the molecular underpinnings of a variety of biological processes

    Isotopic evidence of increasing water abundance and lake hydrological change in Old Crow Flats, Yukon, Canada

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    Lake-rich northern permafrost landscapes are sensitive to changing climate conditions, but ability to track real-time and potentially multiple hydrological responses (e.g. lake expansion, drawdown, drainage) is challenging due to absence of long-term, sustainable monitoring programs in these remote locations. Old Crow Flats (OCF), Yukon, is a Ramsar Wetland of International Importance where concerns about low water levels and their consequences for wildlife habitat and traditional ways of life prompted multidisciplinary studies during the International Polar Year (2007–2008) and led to the establishment of an aquatic ecosystem monitoring program. Here, we report water isotope data from 14 representative thermokarst lakes in OCF, the foundation of the monitoring program, and time-series of derived metrics including the isotope composition of input waters and evaporation-to-inflow ratios for a 13 year period (2007–2019). Although the lakes spanned multiple hydrological categories (i.e. rainfall-, snowmelt- and evaporation-dominated) based on initial surveys, well-defined trends from application of generalized additive models and meteorological records reveal that lakes have become increasingly influenced by rainfall, and potentially waters from thawing permafrost. These sources of input have led to more positive lake water balances. Given the documented role of rainfall in causing thermokarst lake drainage events in OCF and elsewhere, we anticipate increased vulnerability of lateral water export from OCF. This study demonstrates the value of long-term isotope-based monitoring programs for identifying hydrological consequences of climate change in lake-rich permafrost landscapes.Northern Scientific Training Program of Polar Knowledge Canad

    Case report: response to the ERK1/2 inhibitor ulixertinib in BRAF D594G cutaneous melanoma.

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    Melanoma is characterized by oncogenic mutations in pathways regulating cell growth, proliferation, and metabolism. Greater than 80% of primary melanoma cases harbor aberrant activation of the mitogen-activated protein kinase kinase/extracellular-signal-regulated kinase (MEK/ERK) pathway, with oncogenic mutations in BRAF, most notably BRAF V600E, being the most common. Significant progress has been made in BRAF-mutant melanoma using BRAF and MEK inhibitors; however, non-V600 BRAF mutations remain a challenge with limited treatment options. We report the case of an individual diagnosed with stage III BRAF D594G-mutant melanoma who experienced an extraordinary response to the ERK1/2 inhibitor ulixertinib as fourth-line therapy. Ulixertinib was obtained via an intermediate expanded access protocol with unique flexibility to permit both single-agent and combination treatments, dose adjustments, breaks in treatment to undergo surgery, and long-term preventive treatment following surgical resection offering this patient the potential for curative treatment

    CRISPR-enhanced human adipocyte \u27browning\u27 as cell therapy for metabolic disease [preprint]

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    Obesity and type 2 diabetes (T2D) are associated with poor tissue responses to insulin [1,2], disturbances in glucose and lipid fluxes [3-5] and comorbidities including steatohepatitis [6] and cardiovascular disease [7,8]. Despite extensive efforts at prevention and treatment [9,10], diabetes afflicts over 400 million people worldwide [11]. Whole body metabolism is regulated by adipose tissue depots [12-14], which include both lipid-storing white adipocytes and less abundant \u27brown\u27 and \u27brite/beige\u27 adipocytes that express thermogenic uncoupling protein UCP1 and secrete factors favorable to metabolic health [15-18]. Application of clustered regularly interspaced short palindromic repeats (CRISPR) gene editing [19,20] to enhance \u27browning\u27 of white adipose tissue is an attractive therapeutic approach to T2D. However, the problems of cell-selective delivery, immunogenicity of CRISPR reagents and long term stability of the modified adipocytes are formidable. To overcome these issues, we developed methods that deliver complexes of SpyCas9 protein and sgRNA ex vivo to disrupt the thermogenesis suppressor gene NRIP1 [21,22] with near 100% efficiency in human or mouse adipocytes. NRIP1 gene disruption at discrete loci strongly ablated NRIP1 protein and upregulated expression of UCP1 and beneficial secreted factors, while residual Cas9 protein and sgRNA were rapidly degraded. Implantation of the CRISPR-enhanced human or mouse brown-like adipocytes into high fat diet fed mice decreased adiposity and liver triglycerides while enhancing glucose tolerance compared to mice implanted with unmodified adipocytes. These findings advance a therapeutic strategy to improve metabolic homeostasis through CRISPR-based genetic modification of human adipocytes without exposure of the recipient to immunogenic Cas9 or delivery vectors

    Effects of Single and Integrated Water, Sanitation, Handwashing, and Nutrition Interventions on Child Soil-Transmitted Helminth and Giardia infections: A Cluster-Randomized Controlled Trial in Rural Kenya

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    Helminth and protozoan infections affect more than 1 billion children globally. Improving water quality, sanitation, handwashing, and nutrition could be more sustainable control strategies for parasite infections than mass drug administration, while providing other quality of life benefits

    Sex differences in lower urinary tract biology and physiology

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    Abstract Females and males differ significantly in gross anatomy and physiology of the lower urinary tract, and these differences are commonly discussed in the medical and scientific literature. However, less attention is dedicated to investigating the varied development, function, and biology between females and males on a cellular level. Recognizing that cell biology is not uniform, especially in the lower urinary tract of females and males, is crucial for providing context and relevance for diverse fields of biomedical investigation. This review serves to characterize the current understanding of biological sex differences between female and male lower urinary tracts, while identifying areas for future research. First, the differences in overall cell populations are discussed in the detrusor smooth muscle, urothelium, and trigone. Second, the urethra is discussed, including anatomic discussions of the female and male urethra followed by discussions of cellular differences in the urothelial and muscular layers. The pelvic floor is then reviewed, followed by an examination of the sex differences in hormonal regulation, the urinary tract microbiome, and the reticuloendothelial system. Understanding the complex and dynamic development, anatomy, and physiology of the lower urinary tract should be contextualized by the sex differences described in this review
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