46 research outputs found

    The Genome Sequence of the Leaf-Cutter Ant Atta cephalotes Reveals Insights into Its Obligate Symbiotic Lifestyle

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    Leaf-cutter ants are one of the most important herbivorous insects in the Neotropics, harvesting vast quantities of fresh leaf material. The ants use leaves to cultivate a fungus that serves as the colony's primary food source. This obligate ant-fungus mutualism is one of the few occurrences of farming by non-humans and likely facilitated the formation of their massive colonies. Mature leaf-cutter ant colonies contain millions of workers ranging in size from small garden tenders to large soldiers, resulting in one of the most complex polymorphic caste systems within ants. To begin uncovering the genomic underpinnings of this system, we sequenced the genome of Atta cephalotes using 454 pyrosequencing. One prediction from this ant's lifestyle is that it has undergone genetic modifications that reflect its obligate dependence on the fungus for nutrients. Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition. These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects). Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host–microbe symbioses

    Impact of the COVID-19 pandemic on the practice of endocrine surgery.

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    BackgroundThis study investigates the impact of the COVID-19 pandemic on endocrine surgeons.MethodsA survey on the professional, educational, and clinical impact was sent to active and corresponding members of the American Association of Endocrine Surgeons (AAES) in September 2020. Chi-square and paired t-test were used for analysis.Results77 surgeons responded (14.8 %). All reported suspension of elective surgeries; 37.7 % were reassigned to other duties during this time. The median number of cases backlogged was 30 (IQR 15-50). Most surgeons reported decreased clinical volume (74.6 %). The use of virtual platforms for clinical and educational purposes increased from pre-COVID-19 levels (all p < 0.001). Use of in-office procedures (p < 0.001) and length of observation prior to discharge for thyroid surgery (p < 0.05) decreased.ConclusionThe COVID-19 pandemic led to suspension of operations and decreased practice volume for endocrine surgeons. Surgeons increased use of virtual platforms, decreased in-office procedures, and decreased duration of observation for thyroid surgery in response
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