91 research outputs found

    Plastics from Soybean Meal and Furfural

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    It is well known that most protein substances may be hardened to form relatively hard, tough, and water resistant materials by suitable chemical treatment. Perhaps the oldest application of this type is the tanning of leather. Much more modern and of much more popular appeal is the production of some 10,000 tons casein annually to be made into such items as buttons, buckles, fountain pens, and various novelties in an attractive array of pastel colors. While milk casein, hardened by formaldehyde, makes excellent plastics the casein is higher in cost than some available proteins so that the possibility of using other proteins has been given considerable study

    The steady-state transcriptome of the four major life-cycle stages of Trypanosoma cruzi

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    <p>Abstract</p> <p>Background</p> <p>Chronic chagasic cardiomyopathy is a debilitating and frequently fatal outcome of human infection with the protozoan parasite, <it>Trypanosoma cruzi</it>. Microarray analysis of gene expression during the <it>T. cruzi </it>life-cycle could be a valuable means of identifying drug and vaccine targets based on their appropriate expression patterns, but results from previous microarray studies in <it>T. cruzi </it>and related kinetoplastid parasites have suggested that the transcript abundances of most genes in these organisms do not vary significantly between life-cycle stages.</p> <p>Results</p> <p>In this study, we used whole genome, oligonucleotide microarrays to globally determine the extent to which <it>T. cruzi </it>regulates mRNA relative abundances over the course of its complete life-cycle. In contrast to previous microarray studies in kinetoplastids, we observed that relative transcript abundances for over 50% of the genes detected on the <it>T. cruzi </it>microarrays were significantly regulated during the <it>T. cruzi </it>life-cycle. The significant regulation of 25 of these genes was confirmed by quantitative reverse-transcriptase PCR (qRT-PCR). The <it>T. cruzi </it>transcriptome also mirrored published protein expression data for several functional groups. Among the differentially regulated genes were members of paralog clusters, nearly 10% of which showed divergent expression patterns between cluster members.</p> <p>Conclusion</p> <p>Taken together, these data support the conclusion that transcript abundance is an important level of gene expression regulation in <it>T. cruzi</it>. Thus, microarray analysis is a valuable screening tool for identifying stage-regulated <it>T. cruzi </it>genes and metabolic pathways.</p

    Query Large Scale Microarray Compendium Datasets Using a Model-Based Bayesian Approach with Variable Selection

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    In microarray gene expression data analysis, it is often of interest to identify genes that share similar expression profiles with a particular gene such as a key regulatory protein. Multiple studies have been conducted using various correlation measures to identify co-expressed genes. While working well for small datasets, the heterogeneity introduced from increased sample size inevitably reduces the sensitivity and specificity of these approaches. This is because most co-expression relationships do not extend to all experimental conditions. With the rapid increase in the size of microarray datasets, identifying functionally related genes from large and diverse microarray gene expression datasets is a key challenge. We develop a model-based gene expression query algorithm built under the Bayesian model selection framework. It is capable of detecting co-expression profiles under a subset of samples/experimental conditions. In addition, it allows linearly transformed expression patterns to be recognized and is robust against sporadic outliers in the data. Both features are critically important for increasing the power of identifying co-expressed genes in large scale gene expression datasets. Our simulation studies suggest that this method outperforms existing correlation coefficients or mutual information-based query tools. When we apply this new method to the Escherichia coli microarray compendium data, it identifies a majority of known regulons as well as novel potential target genes of numerous key transcription factors

    TRAM (Transcriptome Mapper): database-driven creation and analysis of transcriptome maps from multiple sources

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    <p>Abstract</p> <p>Background</p> <p>Several tools have been developed to perform global gene expression profile data analysis, to search for specific chromosomal regions whose features meet defined criteria as well as to study neighbouring gene expression. However, most of these tools are tailored for a specific use in a particular context (e.g. they are species-specific, or limited to a particular data format) and they typically accept only gene lists as input.</p> <p>Results</p> <p>TRAM (Transcriptome Mapper) is a new general tool that allows the simple generation and analysis of quantitative transcriptome maps, starting from any source listing gene expression values for a given gene set (e.g. expression microarrays), implemented as a relational database. It includes a parser able to assign univocal and updated gene symbols to gene identifiers from different data sources. Moreover, TRAM is able to perform intra-sample and inter-sample data normalization, including an original variant of quantile normalization (scaled quantile), useful to normalize data from platforms with highly different numbers of investigated genes. When in 'Map' mode, the software generates a quantitative representation of the transcriptome of a sample (or of a pool of samples) and identifies if segments of defined lengths are over/under-expressed compared to the desired threshold. When in 'Cluster' mode, the software searches for a set of over/under-expressed consecutive genes. Statistical significance for all results is calculated with respect to genes localized on the same chromosome or to all genome genes. Transcriptome maps, showing differential expression between two sample groups, relative to two different biological conditions, may be easily generated. We present the results of a biological model test, based on a meta-analysis comparison between a sample pool of human CD34+ hematopoietic progenitor cells and a sample pool of megakaryocytic cells. Biologically relevant chromosomal segments and gene clusters with differential expression during the differentiation toward megakaryocyte were identified.</p> <p>Conclusions</p> <p>TRAM is designed to create, and statistically analyze, quantitative transcriptome maps, based on gene expression data from multiple sources. The release includes FileMaker Pro database management runtime application and it is freely available at <url>http://apollo11.isto.unibo.it/software/</url>, along with preconfigured implementations for mapping of human, mouse and zebrafish transcriptomes.</p

    Deterrence in Cyberspace: An Interdisciplinary Review of the Empirical Literature

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    The popularity of the deterrence perspective across multiple scientific disciplines has sparked a lively debate regarding its relevance in influencing both offenders and targets in cyberspace. Unfortunately, due to the invisible borders between academic disciplines, most of the published literature on deterrence in cyberspace is confined within unique scientific disciplines. This chapter therefore provides an interdisciplinary review of the issue of deterrence in cyberspace. It begins with a short overview of the deterrence perspective, presenting the ongoing debates concerning the relevance of deterrence pillars in influencing cybercriminals’ and cyberattackers’ operations in cyberspace. It then reviews the existing scientific evidence assessing various aspects of deterrence in the context of several disciplines: criminology, law, information systems, and political science. This chapter ends with a few policy implications and proposed directions for future interdisciplinary academic research

    DNA immunoprecipitation semiconductor sequencing (DIP-SC-seq) as a rapid method to generate genome wide epigenetic signatures

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    Modification of DNA resulting in 5-methylcytosine (5 mC) or 5-hydroxymethylcytosine (5hmC) has been shown to influence the local chromatin environment and affect transcription. Although recent advances in next generation sequencing technology allow researchers to map epigenetic modifications across the genome, such experiments are often time-consuming and cost prohibitive. Here we present a rapid and cost effective method of generating genome wide DNA modification maps utilising commercially available semiconductor based technology (DNA immunoprecipitation semiconductor sequencing; “DIP-SC-seq”) on the Ion Proton sequencer. Focussing on the 5hmC mark we demonstrate, by directly comparing with alternative sequencing strategies, that this platform can successfully generate genome wide 5hmC patterns from as little as 500 ng of genomic DNA in less than 4 days. Such a method can therefore facilitate the rapid generation of multiple genome wide epigenetic datasets

    Crucial role of calbindin-D28k in the pathogenesis of Alzheimer's disease mouse model

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    Calbindin-D28k (CB), one of the major calcium-binding and buffering proteins, has a critical role in preventing a neuronal death as well as maintaining calcium homeostasis. Although marked reductions of CB expression have been observed in the brains of mice and humans with Alzheimer disease (AD), it is unknown whether these changes contribute to AD-related dysfunction. To determine the pathogenic importance of CB depletions in AD models, we crossed 5 familial AD mutations (5XFAD; Tg) mice with CB knock-out (CBKO) mice and generated a novel line CBKO·5XFAD (CBKOTg) mice. We first identified the change of signaling pathways and differentially expressed proteins globally by removing CB in Tg mice using mass spectrometry and antibody microarray. Immunohistochemistry showed that CBKOTg mice had significant neuronal loss in the subiculum area without changing the magnitude (number) of amyloid β-peptide (Aβ) plaques deposition and elicited significant apoptotic features and mitochondrial dysfunction compared with Tg mice. Moreover, CBKOTg mice reduced levels of phosphorylated mitogen-activated protein kinase (extracellular signal-regulated kinase) 1/2 and cAMP response element-binding protein at Ser-133 and synaptic molecules such as N-methyl-D-aspartate receptor 1 (NMDA receptor 1), NMDA receptor 2A, PSD-95 and synaptophysin in the subiculum compared with Tg mice. Importantly, this is the first experimental evidence that removal of CB from amyloid precursor protein/presenilin transgenic mice aggravates AD pathogenesis, suggesting that CB has a critical role in AD pathogenesis

    Molecular evidence for increased regulatory conservation during metamorphosis, and against deleterious cascading effects of hybrid breakdown in Drosophila

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    <p>Abstract</p> <p>Background</p> <p>Speculation regarding the importance of changes in gene regulation in determining major phylogenetic patterns continues to accrue, despite a lack of broad-scale comparative studies examining how patterns of gene expression vary during development. Comparative transcriptional profiling of adult interspecific hybrids and their parental species has uncovered widespread divergence of the mechanisms controlling gene regulation, revealing incompatibilities that are masked in comparisons between the pure species. However, this has prompted the suggestion that misexpression in adult hybrids results from the downstream cascading effects of a subset of genes improperly regulated in early development.</p> <p>Results</p> <p>We sought to determine how gene expression diverges over development, as well as test the cascade hypothesis, by profiling expression in males of <it>Drosophila melanogaster</it>, <it>D. sechellia</it>, and <it>D. simulans</it>, as well as the <it>D. simulans </it>(♀) × <it>D. sechellia </it>(♂) male F1 hybrids, at four different developmental time points (3rd instar larval, early pupal, late pupal, and newly-emerged adult). Contrary to the cascade model of misexpression, we find that there is considerable stage-specific autonomy of regulatory breakdown in hybrids, with the larval and adult stages showing significantly more hybrid misexpression as compared to the pupal stage. However, comparisons between pure species indicate that genes expressed during earlier stages of development tend to be more conserved in terms of their level of expression than those expressed during later stages, suggesting that while Von Baer's famous law applies at both the level of nucleotide sequence and expression, it may not apply necessarily to the underlying overall regulatory network, which appears to diverge over the course of ontogeny and which can only be ascertained by combining divergent genomes in species hybrids.</p> <p>Conclusion</p> <p>Our results suggest that complex integration of regulatory circuits during morphogenesis may lead to it being more refractory to divergence of underlying gene regulatory mechanisms - more than that suggested by the conservation of gene expression levels between species during earlier stages. This provides support for a 'developmental hourglass' model of divergence of gene expression in <it>Drosophila </it>resulting in a highly conserved pupal stage.</p

    Alterations in gene expression profiles correlated with cisplatin cytotoxicity in the glioma U343 cell line

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    Gliomas are the most common tumors in the central nervous system, the average survival time of patients with glioblastoma multiforme being about 1 year from diagnosis, in spite of harsh therapy. Aiming to study the transcriptional profiles displayed by glioma cells undergoing cisplatin treatment, gene expression analysis was performed by the cDNA microarray method. Cell survival and apoptosis induction following treatment were also evaluated. Drug concentrations of 12.5 to 300 μM caused a pronounced reduction in cell survival rates five days after treatment, whereas concentrations higher than 25 μM were effective in reducing the survival rates to ~1%. However, the maximum apoptosis frequency was 20.4% for 25 μM cisplatin in cells analyzed at 72 h, indicating that apoptosis is not the only kind of cell death induced by cisplatin. An analysis of gene expression revealed 67 significantly (FDR < 0.05) modulated genes: 29 of which down- and 38 up-regulated. These genes belong to several classes (metabolism, protein localization, cell proliferation, apoptosis, adhesion, stress response, cell cycle and DNA repair) that may represent several affected cell processes under the influence of cisplatin treatment. The expression pattern of three genes (RHOA, LIMK2 and TIMP2) was confirmed by the real time PCR method

    Full Sequence and Comparative Analysis of the Plasmid pAPEC-1 of Avian Pathogenic E. coli χ7122 (O78∶K80∶H9)

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    (APEC), are very diverse. They cause a complex of diseases in Human, animals, and birds. Even though large plasmids are often associated with the virulence of ExPEC, their characterization is still in its infancy., are also present in the sequence of pAPEC-1. The comparison of the pAPEC-1 sequence with the two available plasmid sequences reveals more gene loss and reorganization than previously appreciated. The presence of pAPEC-1-associated genes is assessed in human ExPEC by PCR. Many patterns of association between genes are found.The pathotype typical of pAPEC-1 was present in some human strains, which indicates a horizontal transfer between strains and the zoonotic risk of APEC strains. ColV plasmids could have common virulence genes that could be acquired by transposition, without sharing genes of plasmid function
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