160 research outputs found
Localized Fetomaternal Hyperglycemia: Spatial and Kinetic Definition by Positron Emission Tomography
to isolated hyperglycemia in the pregnant rat. mg/dL) localized to the left uterine artery was sustained for at least 48 hours while maternal euglycemia was maintained. fetal effects of isolated hyperglycemia. Broadly, this approach can be extended to study a variety of maternal-sided perturbations suspected to directly affect fetal health
A standard protocol for reporting species distribution models
Species distribution models (SDMs) constitute the most common class of models
across ecology, evolution and conservation. The advent of ready-to-use software pack
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ages and increasing availability of digital geoinformation have considerably assisted
the application of SDMs in the past decade, greatly enabling their broader use for
informing conservation and management, and for quantifying impacts from global
change. However, models must be fit for purpose, with all important aspects of their
development and applications properly considered. Despite the widespread use of
SDMs, standardisation and documentation of modelling protocols remain limited,
which makes it hard to assess whether development steps are appropriate for end use.
To address these issues, we propose a standard protocol for reporting SDMs, with an
emphasis on describing how a study’s objective is achieved through a series of model
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ing decisions. We call this the ODMAP (Overview, Data, Model, Assessment and
Prediction) protocol, as its components reflect the main steps involved in building
SDMs and other empirically-based biodiversity models. The ODMAP protocol serves
two main purposes. First, it provides a checklist for authors, detailing key steps for model building and analyses, and thus represents a quick guide and generic workflow for modern SDMs. Second, it introduces
a structured format for documenting and communicating the models, ensuring transparency and reproducibility, facilitating
peer review and expert evaluation of model quality, as well as meta-analyses. We detail all elements of ODMAP, and explain
how it can be used for different model objectives and applications, and how it complements efforts to store associated metadata
and define modelling standards. We illustrate its utility by revisiting nine previously published case studies, and provide an
interactive web-based application to facilitate its use. We plan to advance ODMAP by encouraging its further refinement and
adoption by the scientific community
Plant-Type Trehalose Synthetic Pathway in Cryptosporidium and Some Other Apicomplexans
The trehalose synthetic pathway is present in bacteria, fungi, plants and invertebrate animals, but is absent in vertebrates. This disaccharide mainly functions as a stress protectant against desiccation, heat, cold and oxidation. Genes involved in trehalose synthesis have been observed in apicomplexan parasites, but little was known about these enzymes. Study on trehalose synthesis in apicomplexans would not only shed new light into the evolution of this pathway, but also provide data for exploring this pathway as novel drug target.We have observed the presence of the trehalose synthetic pathway in Cryptosporidium and other apicomplexans and alveolates. Two key enzymes (trehalose 6-phosphate synthase [T6PS; EC 2.4.1.15] and trehalose phosphatase [TPase; EC 3.1.3.12] are present as Class II bifunctional proteins (T6PS-TPase) in the majority of apicomplexans with the exception of Plasmodium species. The enzyme for synthesizing the precursor (UDP-glucose) is homologous to dual-substrate UDP-galactose/glucose pyrophosphorylases (UGGPases), rather than the "classic" UDP-glucose pyrophosphorylase (UGPase). Phylogenetic recontructions indicate that both T6PS-TPases and UGGPases in apicomplexans and other alveolates are evolutionarily affiliated with stramenopiles and plants. The expression level of T6PS-TPase in C. parvum is highly elevated in the late intracellular developmental stage prior to or during the production of oocysts, implying that trehalose may be important in oocysts as a protectant against environmental stresses. Finally, trehalose has been detected in C. parvum oocysts, thus confirming the trehalose synthetic activity in this parasite.A trehalose synthetic pathway is described in the majority of apicomplexan parasites including Cryptosporidium and the presence of trehalose was confirmed in the C. parvum oocyst. Key enzymes in the pathway (i.e., T6PS-TPase and UGGPase) are plant-type and absent in humans and animals, and may potentially serve as novel drug targets in the apicomplexans
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