286 research outputs found

    Toward development of continuous bioprocesses: Comparison of fed-batch and perfusion upstream production processes in early development

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    Continuous Processing is an exciting development in the field of bioprocessing. The potential for quick response to market demands, decrease in infrastructure, increased flexibility and consistent product quality has resulted in a growing interest in Continuous Processing for production of all types of protein drugs (high or low volume, stable or unstable). Sanofi is developing a novel Integrated Continuous Manufacturing platform for biologics that utilizes an upstream perfusion process. While cell culture perfusion processes offer substantial benefits for commercial biologics production, implementation may present challenges in early development, where speed to first in man studies is critical. Here we present a comparison of candidate Phase I fed-batch and perfusion processes resulting from our upstream development work for a monoclonal antibody. The report focuses on process productivity, product quality attributes, and development timelines. Assessment of the advantages and challenges for both processes informs strategy for Continuous Process platform developmen

    Lessons Learned during Thermal Hardware Integration on the Global Precipitation Measurement Satellite

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    The Global Precipitation Measurement mission is a joint NASA/JAXA mission scheduled for launch in late 2013. The integration of thermal hardware onto the satellite began in the Fall of 2010 and will continue through the Summer of 2012. The thermal hardware on the mission included several constant conductance heat pipes, heaters, thermostats, thermocouples radiator coatings and blankets. During integration several problems arose and insights were gained that would help future satellite integrations. Also lessons learned from previous missions were implemented with varying degrees of success. These insights can be arranged into three categories. 1) the specification of flight hardware using analysis results and the available mechanical resources. 2) The integration of thermal flight hardware onto the spacecraft, 3) The preparation and implementation of testing the thermal flight via touch tests, resistance measurements and thermal vacuum testing

    Functional Analysis of Tpr: Identification of Nuclear Pore Complex Association and Nuclear Localization Domains and a Role in mRNA Export

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    Tpr is a 270-kD coiled-coil protein localized to intranuclear filaments of the nuclear pore complex (NPC). The mechanism by which Tpr contributes to the structure and function of the nuclear pore is currently unknown. To gain insight into Tpr function, we expressed the full-length protein and several subdomains in mammalian cell lines and examined their effects on nuclear pore function. Through this analysis, we identified an NH2-terminal domain that was sufficient for association with the nucleoplasmic aspect of the NPC. In addition, we unexpectedly found that the acidic COOH terminus was efficiently transported into the nuclear interior, an event that was apparently mediated by a putative nuclear localization sequence. Ectopic expression of the full-length Tpr caused a dramatic accumulation of poly(A)+ RNA within the nucleus. Similar results were observed with domains that localized to the NPC and the nuclear interior. In contrast, expression of these proteins did not appear to affect nuclear import. These data are consistent with a model in which Tpr is tethered to intranuclear filaments of the NPC by its coiled coil domain leaving the acidic COOH terminus free to interact with soluble transport factors and mediate export of macromolecules from the nucleus

    Single mRNAs visualized by ultrastructural in situ hybridization are principally localized at actin filament intersections in fibroblasts

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    Considerable evidence indicates that mRNA associates with structural filaments in the cell (cytoskeleton). This relationship would be an important mechanism to effect mRNA sorting since specific mRNAs could be sequestered at sites within the cell. In addition, it can provide a mechanism for spatial regulation of mRNA expression. However, the precise structural interactions between mRNA and the cytoskeleton have yet to be defined. An objective of this work was to visualize individual poly(A) mRNA molecules in situ by electron microscopy to identify their relationship to individual filaments. Poly(A) RNA and filaments were identified simultaneously using antibodies to detect hybridized probe and filaments or actin-binding proteins. In human fibroblasts, most of the poly(A) mRNA (72%) was localized within 5 nm of orthogonal networks of F-actin filaments. Poly(A) mRNA also colocalized with vimentin filaments (29%) and microtubules (\u3c 10%). The sites of mRNA localization were predominantly at filament intersections. The majority of poly(A) mRNA and polysomes colocalized with the actin crosslinking proteins, filamin, and alpha-actinin, and the elongation factor, EF-1 alpha (actin-binding protein; ABP-50). Evidence that intersections contained single mRNA molecules was provided by using a labeled oligo dT probe to prime the synthesis of cDNA in situ using reverse transcriptase. Both the poly(A) and cis sequences of the same mRNA molecule could then be visualized independently. We propose that the cytoskeletal intersection is a mRNA receptor and serves as a microdomain where mRNA is attached and functionally expressed

    Atg6 is required for multiple vesicle trafficking pathways and hematopoiesis in Drosophila

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    Atg6 (beclin 1 in mammals) is a core component of the Vps34 complex that is required for autophagy. Beclin 1 (Becn1) functions as a tumor suppressor, and Becn1(+/-) tumors in mice possess elevated cell stress and p62 levels, altered NF-kappaB signaling and genome instability. The tumor suppressor function of Becn1 has been attributed to its role in autophagy, and the potential functions of Atg6/Becn1 in other vesicle trafficking pathways for tumor development have not been considered. Here, we generate Atg6 mutant Drosophila and demonstrate that Atg6 is essential for autophagy, endocytosis and protein secretion. By contrast, the core autophagy gene Atg1 is required for autophagy and protein secretion, but it is not required for endocytosis. Unlike null mutants of other core autophagy genes, all Atg6 mutant animals possess blood cell masses. Atg6 mutants have enlarged lymph glands (the hematopoietic organ in Drosophila), possess elevated blood cell numbers, and the formation of melanotic blood cell masses in these mutants is not suppressed by mutations in either p62 or NFkappaB genes. Thus, like mammals, altered Atg6 function in flies causes hematopoietic abnormalities and lethality, and our data indicate that this is due to defects in multiple membrane trafficking processes

    No Evidence of HIV and SIV Sequences in Two Separate Lots of Polio Vaccines Used in the First U.S. Polio Vaccine Campaign

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    AbstractWe obtained sealed vials of two different polio vaccine lots, expiration date 1955, which were used in the first U.S. polio vaccine campaign. These early lots were pulled from the market because they contained live infectious poliovirus which caused polio in some of the vaccines. Theoretically, these vaccines could have contained other infectious retroviruses, including HIV. No viral sequences were detected using RT-PCR analyses with primers capable of amplifying chimpanzee SIV and HIV-1-related viruses nor with primers for macaque SIV, sooty mangabey SIV, and HIV-2-related viruses. Poliovirus sequences were readily amplified by RT-PCR, suggesting that the technique used would have detected SIV or HIV sequences, if present

    Computations and observations on congruence covering systems

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    A covering system\textit{covering system} is a collection of integer congruences such that every integer satisfies at least one congruence in the collection. A covering system is called distinct\textit{distinct} if all of its moduli are distinct. An expansive literature has developed on covering systems since their introduction by Erd\H{o}s. Here we present elementary observations on covering systems, including some approaches we believe to be original. We also present substantial new computational results, including a full classification of distinct covering systems with at most ten moduli, which we group together based on two forms of equivalence. In addition, we confirm the minimum cardinality of a distinct covering system with all moduli exceeding 22, which is 1111.Comment: 9 pages, one tabl

    Non-excitable fluorescent protein orthologs found in ctenophores

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    Background: Fluorescent proteins are optically active proteins found across many clades in metazoans. A fluorescent protein was recently identified in a ctenophore, but this has been suggested to derive from a cnidarian, raising again the question of origins of this group of proteins. Results: Through analysis of transcriptome data from 30 ctenophores, we identified a member of an orthologous group of proteins similar to fluorescent proteins in each of them, as well as in the genome of Mnemiopsis leidyi. These orthologs lack canonical residues involved in chromophore formation, suggesting another function. Conclusions: The phylogenetic position of the ctenophore protein family among fluorescent proteins suggests that this gene was present in the common ancestor of all ctenophores and that the fluorescent protein previously found in a ctenophore actually derives from a siphonophore

    Nanocuration workflows: Establishing best practices for identifying, inputting, and sharing data to inform decisions on nanomaterials

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    There is a critical opportunity in the field of nanoscience to compare and integrate information across diverse fields of study through informatics (i.e., nanoinformatics). This paper is one in a series of articles on the data curation process in nanoinformatics (nanocuration). Other articles in this series discuss key aspects of nanocuration (temporal metadata, data completeness, database integration), while the focus of this article is on the nanocuration workflow, or the process of identifying, inputting, and reviewing nanomaterial data in a data repository. In particular, the article discusses: 1) the rationale and importance of a defined workflow in nanocuration, 2) the influence of organizational goals or purpose on the workflow, 3) established workflow practices in other fields, 4) current workflow practices in nanocuration, 5) key challenges for workflows in emerging fields like nanomaterials, 6) examples to make these challenges more tangible, and 7) recommendations to address the identified challenges. Throughout the article, there is an emphasis on illustrating key concepts and current practices in the field. Data on current practices in the field are from a group of stakeholders active in nanocuration. In general, the development of workflows for nanocuration is nascent, with few individuals formally trained in data curation or utilizing available nanocuration resources (e.g., ISA-TAB-Nano). Additional emphasis on the potential benefits of cultivating nanomaterial data via nanocuration processes (e.g., capability to analyze data from across research groups) and providing nanocuration resources (e.g., training) will likely prove crucial for the wider application of nanocuration workflows in the scientific community
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