77 research outputs found

    Armstrong Calculus

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    Authors\u27 Description: An open-source textbook for calculus. The text is mostly an adaptation of two other excellent open- source calculus textbooks: Active Calculus by Dr. Matt Boelkins of Grand Valley State University and Drs. Gregory Hartman, Brian Heinold, Troy Siemers, Dimplekumar Chalishajar, and Jennifer Bowen of the Virginia Military Institute and Mount Saint Mary\u27s University. Both of these texts can be found at http://aimath.org/textbooks/approved-textbooks/. The authors of this text have combined sections, examples, and exercises from the above two texts along with some of their own content to generate this text. The impetus for the creation of this text was to adopt an open-source textbook for Calculus while maintaining the typical schedule and content of the calculus sequence at our home institution. Accessible files with optical character recognition (OCR) and auto-tagging provided by the Center for Inclusive Design and Innovation.https://oer.galileo.usg.edu/mathematics-textbooks/1000/thumbnail.jp

    Elementary Statistics

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    This Grants Collection for Elementary Statistics was created under a Round Four ALG Textbook Transformation Grant. Affordable Learning Georgia Grants Collections are intended to provide faculty with the frameworks to quickly implement or revise the same materials as a Textbook Transformation Grants team, along with the aims and lessons learned from project teams during the implementation process. Documents are in .pdf format, with a separate .docx (Word) version available for download. Each collection contains the following materials: Linked Syllabus Initial Proposal Final Reporthttps://oer.galileo.usg.edu/mathematics-collections/1003/thumbnail.jp

    Separation and identification of permethylated glycan isomers by reversed phase nanoLC-NSI-MSn [preprint]

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    High performance liquid chromatography has been employed for decades to enhance detection sensitivity and quantification of complex analytes within biological mixtures. Among these analytes, glycans released from glycoproteins and glycolipids have been characterized as underivatized or fluorescently tagged derivatives by HPLC coupled to various detection methods. These approaches have proven extremely useful for profiling the structural diversity of glycoprotein and glycolipid glycosylation but require the availability of glycan standards and secondary orthogonal degradation strategies to validate structural assignments. A robust method for HPLC separation of glycans as their permethylated derivatives, coupled with in-line MSn fragmentation to assign structural features independent of standards, would significantly enhance the depth of knowledge obtainable from biological samples. Here, we report an optimized workflow for LC-MS analysis of permethylated glycans that includes sample preparation, mobile phase optimization, and MSn method development to resolve structural isomers on-the-fly. We report baseline separation and MSn fragmentation of isomeric N- and O-glycan structures, aided by supplementing mobile phases with Li+, which simplifies adduct heterogeneity and facilitates cross-ring fragmentation to obtain valuable monosaccharide linkage information. Our workflow has been adapted from standard proteomics-based workflows and, therefore, provides opportunities for laboratories with expertise in proteomics to acquire glycomic data with minimal deviation from existing buffer systems, chromatography media, and instrument configurations. Furthermore, our workflow does not require a mass spectrometer with high-resolution/accurate mass capabilities. The rapidly evolving appreciation of the biological significance of glycans for human health and disease requires the implementation of high-throughput methods to identify and quantify glycans harvested from sample sets of sufficient size to achieve appropriately powered statistical significance. The LC-MSn approach we report generates glycan isomeric separations, robust structural characterization, and is amenable to auto-sampling with associated throughput enhancements

    Modeling Congenital Disorders of N-Linked Glycoprotein Glycosylation in Drosophila melanogaster

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    Protein glycosylation, the enzymatic addition of N-linked or O-linked glycans to proteins, serves crucial functions in animal cells and requires the action of glycosyltransferases, glycosidases and nucleotide-sugar transporters, localized in the endoplasmic reticulum and Golgi apparatus. Congenital Disorders of Glycosylation (CDGs) comprise a family of multisystemic diseases caused by mutations in genes encoding proteins involved in glycosylation pathways. CDGs are classified into two large groups. Type I CDGs affect the synthesis of the dolichol-linked Glc3Man9GlcNac2 precursor of N-linked glycosylation or its transfer to acceptor proteins. Type II CDG (CDG-II) diseases impair either the trimming of the N-linked oligosaccharide, the addition of terminal glycans or the biosynthesis of O-linked oligosaccharides, which occur in the Golgi apparatus. So far, over 100 distinct forms of CDGs are known, with the majority of them characterized by neurological defects including mental retardation, seizures and hypotonia. Yet, it is unclear how defective glycosylation causes the pathology of CDGs. This issue can be only addressed by developing animal models of specific CDGs. Drosophila melanogaster is emerging as a highly suitable organism for analyzing glycan-dependent functions in the central nervous system (CNS) and the involvement of N-glycosylation in neuropathologies. In this review we illustrate recent work that highlights the genetic and neurobiologic advantages offered by D. melanogaster for dissecting glycosylation pathways and modeling CDG pathophysiology

    Glycan profiles of gp120 protein vaccines from four major HIV-1 subtypes produced from different host cell lines under non-GMP or GMP conditions

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    Envelope glycoprotein (Env) of human immunodeficiency virus type 1 (HIV-1) is an important target for the development of an HIV vaccine. Extensive glycosylation of Env is an important feature that both protects the virus from antibody responses and serves as a target for some highly potent broadly neutralizing antibodies. Therefore, analysis of glycans on recombinant Env proteins is highly significant. Here we present glycosylation profiles of recombinant gp120 proteins from four major clades of HIV-1 (A, B, C, and AE) produced either as research-grade material in 293 and CHO cells or as two independent lots of clinical material under GMP conditions. Almost all potential N-linked glycosylation sites were at least partially occupied in all proteins. The occupancy rates were largely consistent among proteins produced under different conditions, although a few sites showed substantial variability even between two GMP lots. Our data confirmed previous studies in the field showing high abundance of oligomannose on Env protein, with 40-50% of glycans having Man5-Man9 on all four proteins under all production conditions. Overall the differences in occupancy and glycan forms among Env from different subtypes produced under different conditions were less dramatic than anticipated and antigenicity analysis with a panel of six monoclonal antibodies showed that all four gp120s maintained their antibody-binding profiles, including antibodies that recognize glycan forms. Such findings have major implications to the final production of a clinical HIV vaccine including Env glycoprotein components. IMPORTANCE HIV-1 Env protein is a major target for the development of an HIV-1 vaccine. Env is covered with a large number of sugar-based glycan forms - about 50% of the Env molecular weight is composed of glycans. Glycan analysis of recombinant Env proteins is important to understand its roles in vial pathogenesis and immune responses. The current report presents the first extensive comparison of glycosylation patterns of recombinant gp120 proteins from four major clades of HIV-1 produced in two different cell lines, grown at either laboratory condition or at 50L GMP scale across different lots. Information learned in this study is valuable for the further design and production of HIV-1 Env proteins as the critical components of HIV-1 vaccine formulations

    Biosynthesis of the major brain gangliosides GD1a and GT1b

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    Gangliosides-sialylated glycosphingolipids-are the major glycoconjugates of nerve cells. The same four structures-GM1, GD1a, GD1b and GT1b-comprise the great majority of gangliosides in mammalian brains. They share a common tetrasaccharide core (Gal1-3GalNAc1-4Gal1-4Glc1-1′Cer) with one or two sialic acids on the internal galactose and zero (GM1 and GD1b) or one (GD1a and GT1b) 2-3-linked sialic acid on the terminal galactose. Whereas the genes responsible for the sialylation of the internal galactose are known, those responsible for terminal sialylation have not been established in vivo. We report that St3gal2 and St3gal3 are responsible for nearly all the terminal sialylation of brain gangliosides in the mouse. When brain ganglioside expression was analyzed in adult St3gal1-, St3gal2-, St3gal3-and St3gal4-null mice, only St3gal2-null mice differed significantly from wild type, expressing half the normal amount of GD1a and GT1b. St3gal1/2-double-null mice were no different than St3gal2-single-null mice; however, St3gal2/3-double-null mice were >95 depleted in gangliosides GD1a and GT1b. Total ganglioside expression (lipid-bound sialic acid) in the brains of St3gal2/3-double-null mice was equivalent to that in wild-type mice, whereas total protein sialylation was reduced by half. St3gal2/3-double-null mice were small, weak and short lived. They were half the weight of wild-type mice at weaning and displayed early hindlimb dysreflexia. We conclude that the St3gal2 and St3gal3 gene products (ST3Gal-II and ST3Gal-III sialyltransferases) are largely responsible for ganglioside terminal 2-3 sialylation in the brain, synthesizing the major brain gangliosides GD1a and GT1b. © 2012 The Author.Fil: Sturgill, Elizabeth R.. Johns Hopkins School Of Medicine; Estados Unidos. University Johns Hopkins; Estados UnidosFil: Aoki, Kazuhiro. University of Georgia; Estados UnidosFil: Lopez, Pablo. University Johns Hopkins; Estados UnidosFil: Colacurcio, Daniel. University Johns Hopkins; Estados UnidosFil: Vajn, Katarina. University Johns Hopkins; Estados UnidosFil: Lorenzini, Ileana. University Johns Hopkins; Estados UnidosFil: Majic, Senka. University Johns Hopkins; Estados UnidosFil: Yang, Won Ho. University of California; Estados UnidosFil: Heffer, Marija. J. J. Strossmayer University; CroaciaFil: Tiemeyer, Michael. University of Georgia; Estados UnidosFil: Marth, Jamey D.. University of California; Estados UnidosFil: Schnaar, Ronald L.. University Johns Hopkins; Estados Unido

    Phosphatidic acid phospholipase A1 mediates ER-Golgi transit of a family of G protein-coupled receptors

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    The coat protein II (COPII)-coated vesicular system transports newly synthesized secretory and membrane proteins from the endoplasmic reticulum (ER) to the Golgi complex. Recruitment of cargo into COPII vesicles requires an interaction of COPII proteins either with the cargo molecules directly or with cargo receptors for anterograde trafficking. We show that cytosolic phosphatidic acid phospholipase A1 (PAPLA1) interacts with COPII protein family members and is required for the transport of Rh1 (rhodopsin 1), an N-glycosylated G protein-coupled receptor (GPCR), from the ER to the Golgi complex. In papla1 mutants, in the absence of transport to the Golgi, Rh1 is aberrantly glycosylated and is mislocalized. These defects lead to decreased levels of the protein and decreased sensitivity of the photoreceptors to light. Several GPCRs, including other rhodopsins and Bride of sevenless, are similarly affected. Our findings show that a cytosolic protein is necessary for transit of selective transmembrane receptor cargo by the COPII coat for anterograde trafficking

    Functional implications of glycans and their curation:insights from the workshop held at the 16th Annual International Biocuration Conference in Padua, Italy

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    Dynamic changes in protein glycosylation impact human health and disease progression. However, current resources that capture disease and phenotype information focus primarily on the macromolecules within the central dogma of molecular biology (DNA, RNA, proteins). To gain a better understanding of organisms, there is a need to capture the functional impact of glycans and glycosylation on biological processes. A workshop titled "Functional impact of glycans and their curation" was held in conjunction with the 16th Annual International Biocuration Conference to discuss ongoing worldwide activities related to glycan function curation. This workshop brought together subject matter experts, tool developers, and biocurators from over 20 projects and bioinformatics resources. Participants discussed four key topics for each of their resources: (i) how they curate glycan function-related data from publications and other sources, (ii) what type of data they would like to acquire, (iii) what data they currently have, and (iv) what standards they use. Their answers contributed input that provided a comprehensive overview of state-of-the-art glycan function curation and annotations. This report summarizes the outcome of discussions, including potential solutions and areas where curators, data wranglers, and text mining experts can collaborate to address current gaps in glycan and glycosylation annotations, leveraging each other's work to improve their respective resources and encourage impactful data sharing among resources. Database URL: https://wiki.glygen.org/Glycan_Function_Workshop_2023
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