84 research outputs found

    Citizen science and online data: Opportunities and challenges for snake ecology and action against snakebite

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    The secretive behavior and life history of snakes makes studying their biology, distribution, and the epidemiology of venomous snakebite challenging. One of the most useful, most versatile, and easiest to collect types of biological data are photographs, particularly those that are connected with geographic location and date-time metadata. Photos verify occurrence records, provide data on phenotypes and ecology, and are often used to illustrate new species descriptions, field guides and identification keys, as well as in training humans and computer vision algorithms to identify snakes. We scoured eleven online and two offline sources of snake photos in an attempt to collect as many photos of as many snake species as possible, and attempt to explain some of the inter-species variation in photograph quantity among global regions and taxonomic groups, and with regard to medical importance, human population density, and range size. We collected a total of 725,565 photos—between 1 and 48,696 photos of 3098 of the world's 3879 snake species (79.9%), leaving 781 “most wanted” species with no photos (20.1% of all currently-described species as of the December 2020 release of The Reptile Database). We provide a list of most wanted species sortable by family, continent, authority, and medical importance, and encourage snake photographers worldwide to submit photos and associated metadata, particularly of “missing” species, to the most permanent and useful online archives: The Reptile Database, iNaturalist, and HerpMapper.ISSN:2590-171

    Assessment of acute myocardial infarction: current status and recommendations from the North American society for cardiovascular imaging and the European society of cardiac radiology

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    There are a number of imaging tests that are used in the setting of acute myocardial infarction and acute coronary syndrome. Each has their strengths and limitations. Experts from the European Society of Cardiac Radiology and the North American Society for Cardiovascular Imaging together with other prominent imagers reviewed the literature. It is clear that there is a definite role for imaging in these patients. While comparative accuracy, convenience and cost have largely guided test decisions in the past, the introduction of newer tests is being held to a higher standard which compares patient outcomes. Multicenter randomized comparative effectiveness trials with outcome measures are required

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    MORPHOLOGICAL STUDIES IN EXPERIMENTAL CRETINISM

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    Non-H-2 genes alter the H-2 determined susceptibilities in immune complex nephritis

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    Non-H-2 genes alter the H-2 determined susceptibilities in immune complex nephritis. These experiments examined the effects of genes outside of the H-2 region on disease susceptibility and pathogenesis. Four strains of mice with the susceptible H-2 type, H-2d, but different non-H-2 genes were studied. B10.D2, Balb/c, NZB, and DBA/2J mice were injected with 4mg of apoferritin i.p. q.d. for 28 days. B10.D2 and Balb/c mice developed proliferative and crescentic glomerulonephritis. NZB mice developed proliferative and crescentic glomerulonephritis with wire loop lesions suggestive of lupus. DBA/2J mice developed only minimal mesangial proliferation without crescents or necrosis. Electron microscopy showed subepithelial and mesangial deposits in B10.D2, moderate subepithelial and mesangial deposits in Balb/c, and marked mesangial, subendothelial and subepithelial deposits in NZB. Immunofluorescence demonstrated the presence of IgG, IgM, C3 and apoferritin in these deposits. The DBA/2J mice had only minimal mesangial deposits by immunofluorescence and electron microscopy. These experiments demonstrate that non-H-2 genes alter the H-2d determined disease susceptibility seen in H-2 congenic mice. NZB genes can alter the disease so that lupus-like lesions develop and DBA/2J genes can substantially ameliorate the disease

    The Ctf18RFC Clamp Loader Is Essential for Telomere Stability in Telomerase-Negative and <i>mre11</i> Mutant Alleles

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    <div><p>The function of the replication clamp loaders in the semi-conservative telomere replication and their relationship to telomerase- and recombination mechanisms of telomere addition remains ambiguous. We have investigated the variant clamp loader Ctf18 RFC (Replication Factor C). To understand the role of Ctf18 at the telomere, we first investigated genetic interactions after loss of Ctf18 and TLC1 (the yeast telomerase RNA). We find that the <i>tlc1▵ ctf18▵</i> double mutant confers a rapid >1000-fold decrease in viability. The rate of loss was similar to the kinetics of cell death in <i>rad52▵ tlc1▵</i> cells. However, the Ctf18 pathway is distinct from Rad52, required for the repair of DSBs, as demonstrated by the synthetic lethality of <i>rad52▵ tlc1▵ ctf18▵</i> triple mutants. These data suggest that each mutant elicits non-redundant defects acting on the same substrate. Second, interactions of the yeast hyper-recombinational mutant, <i>mre11A470T, with ctf18▵</i> confer a synergistic cold sensitivity. The phenotype of these double mutants ultimately results in telomere loss and the generation of recombinational survivors. We observed a similar synergism between single mutants that led to hypersensitivity to the DNA alkylating agent, methane methyl sulphonate (MMS), the replication fork inhibitor hydroxyurea (HU), and to a failure to separate telomeres of sister chromatids. Hence, <i>ctf18▵</i> and <i>mre11A470T</i> act in different pathways on telomere substrates for multiple phenotypes. The <i>mre11A470T</i> cells also displayed a DNA damage response (DDR) at 15°C but not at 30°C while <i>ctf18▵</i> mutants conferred a constitutive DDR activity. Both the 15°C DDR pattern and growth rate were reversible at 30°C and displayed telomerase activity <i>in vivo</i>. We hypothesize that Ctf18 confers protection against stalling and/or breaks at the replication fork in cells that either lack, or are compromised for, telomerase activity. This Ctf18-based function is likely to contribute another level to telomere size homeostasis.</p></div

    <i>mre11A470T ctf18</i>▵ cold sensitive survivors arise via recombinational mechanisms.

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    <p>[<b>GT</b>] DNA isolated from the indicated strains (top) grown at 30°C and 15°C and from ten independent survivors (1–10) were digested with XhoI and Southern analysis performed using poly GT as a telomeric probe. Arrow on right indicates position of Type I survivor. Note that the smearing of the distribution that represents the distribution of Type II-like survivors. [<b>PEP4</b>] Southern blot from above was stripped and probed with <i>PEP4</i> sequences as an internal loading control.</p

    Western blot analysis of DNA damage responses to <i>mre11A470T</i> and <i>ctf18</i>▵ Mutations.

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    <p>[<b>Top</b>]: Protein extracts were isolated from wild-type, <i>mre11A470T</i>, <i>ctf18▵</i> and <i>mre11A470T ctf18▵</i> cultures grown in 5 ml YPD cultures at 30°C or 15°C. Extracts were subjected to electrophoresis on a 10% SDS-PAGE gel prior to Western analysis using goat primary polyclonal anti-Rad53 antibody as described in Materials and Methods. Phosphorylated forms (arrows on right) migrate more slowly than the un-phosphorylated species. [<b>Bottom</b>]: Protein extracts were isolated from cold resistant <i>mre11A470T ctf18Δ</i> survivors and grown in 5 ml YPD at 15°C before shifting to 30°C. Extracts were subjected to Western analysis for Rad53 expression as described above.</p
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