Publications by authors named "John Buswell"

The survival of Homo sapiens is continually under threat from agencies capable of inflicting calamitous damage to the overall health and well-being of humankind. One strategy aimed at combatting this threat is focused on medicinal mushrooms and derivatives thereof. Mushrooms themselves have been consumed as part of the human diet for centuries, whereas 'mushroom nutriceuticals' is a more recently adopted term describing mushroom-derived products taken as dietary supplements to enhance general health and fitness.

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Nanopore sequencing devices read individual RNA strands directly. This facilitates identification of exon linkages and nucleotide modifications; however, using conventional direct RNA nanopore sequencing, the 5' and 3' ends of poly(A) RNA cannot be identified unambiguously. This is due in part to RNA degradation in vivo and in vitro that can obscure transcription start and end sites.

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We have determined the production profiles of major ligno(hemi)cellulolytic enzymes at different stages of the mushroom development cycle during industrial scale cultivation of Pleurotus eryngii on supplemented agri-wastes. Endo-1,4-β-glucanase, cellobiohydrolase and endoxylanase levels remained relatively low during substrate colonization, increased sharply when small fruit bodies appeared, and peaked at maturation. β-Glucosidase and β-xylosidase levels decreased when substrate colonization was complete, increased with the appearance of small fruit bodies and primordia, respectively, and reached maxima at maturation.

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Eukaryotic mRNAs are modified at their 5' end early during transcription by the addition of N7-methylguanosine (mG), which forms the "cap" on the first 5' nucleotide. Identification of the 5' nucleotide on mRNA is necessary for determination of the Transcription Start Site (TSS). We explored the effect of various reaction conditions on the activity of the yeast scavenger mRNA decapping enzyme DcpS and examined decapping of 30 chemically distinct cap structures varying the state of methylation, sugar, phosphate linkage, and base composition on 25mer RNA oligonucleotides.

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Background: The initiating nucleotide found at the 5' end of primary transcripts has a distinctive triphosphorylated end that distinguishes these transcripts from all other RNA species. Recognizing this distinction is key to deconvoluting the primary transcriptome from the plethora of processed transcripts that confound analysis of the transcriptome. The currently available methods do not use targeted enrichment for the 5'end of primary transcripts, but rather attempt to deplete non-targeted RNA.

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The ability to specifically attach chemical probes to individual proteins represents a powerful approach to the study and manipulation of protein function in living cells. It provides a simple, robust and versatile approach to the imaging of fusion proteins in a wide range of experimental settings. However, a potential drawback of detection using chemical probes is the fluorescence background from unreacted or nonspecifically bound probes.

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Fluorescent tagging of proteins has become a critical step in optical analysis of protein function in vitro and in living cells. Here we describe a two-tag system for expression and isolation of a protein of interest from Escherichia coli and subsequent site-specific fluorescent labeling with Sfp phosphopantetheinyl transferase (Sfp synthase). In the example presented, adenoviral protein E3-14.

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Article Synopsis
  • Intein-mediated protein ligation (IPL) uses an intein to create proteins with a C-terminal thioester, enabling attachment to other proteins or peptides with an amino-terminal cysteine.
  • This method allows for isolation and labeling of recombinant proteins in E. coli by using synthetic short peptides containing a fluorescent group.
  • The chapter further discusses important factors influencing intein-mediated cleavage and ligation processes.
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We have compared the induction of an endoglucanase (EG1) by α-lactose and/or cellobiose, with or without added L-sorbose, in submerged cultures of Volvariella volvacea, to better understand the mechanism whereby cellulase formation is triggered by these soluble disaccharides. EG1 levels induced by α-lactose and cellobiose were 28.6% and 6.

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A beta-glucosidase, with a molecular mass of 95 kDa, was isolated from extracts of Volvariella volvacea mycelium grown on crystalline cellulose. Degenerate primers based on the N-terminal sequences of purified beta-glucosidase and two protease-generated peptides were used to generate cDNA fragments encoding a portion of the beta-glucosidase gene (bgl), and rapid amplification of cDNA ends was used to obtain full-length cDNA clones. The cDNA of bgl contained an ORF of 2586 bp coding for 862 amino acids.

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We used PCR-based methods to clone and sequence four previously unidentified cellulase cDNAs: cbhI-I, cbhI-II, cbhII-I and egII. CbhI-I, cbhI-II and cbhII-I consist of 1710, 1610 and 1453 bp, respectively, and encode for 512, 458 and 442 amino acids, respectively. EgII consists of 1180 bp encoding for 310 amino acids, and belongs to family 61 of the glycosyl hydrolases.

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Cloning of a laccase-encoding cDNA from the edible straw mushroom, Volvariella volvacea, was performed using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends. The cDNA of the putative laccase gene (lac4) consisted of 1689 bp, including an open reading frame encoding a 23-amino acid signal peptide at the N-terminal end and a 540-amino acid mature protein with a predicted molecular mass of 58173 Da and a pI value of 6.1.

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We have isolated a laccase (lac1) from culture fluid of Volvariella volvacea, grown in a defined medium containing 150 micro m CuSO4, by ion-exchange and gel filtration chromatography. Lac1 has a molecular mass of 58 kDa as determined by SDS/PAGE and an isoelectric point of 3.7.

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Volvariella volvacea, strain V14, produces multiple forms of extracellular laccase when grown in submerged culture in a defined medium with glucose as sole carbon source, and on cotton waste 'compost' representative of the conditions used for industrial-scale mushroom cultivation. In liquid culture, enzyme synthesis is associated with the onset of secondary growth, and is positively regulated by copper (up to 200 microM CuSO(4)) and by various aromatic compounds. In solid-state systems, only low levels of laccase are detectable during the vegetative growth phase but enzyme activity increases sharply at the onset of fruiting and during sporophore development.

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Using the single-cell gel electrophoresis ("Comet") assay, we show that tyrosinase-generated L-DOPA oxidation products prevent H2O2-induced oxidative DNA damage in cultured tissue cells. We propose that these oxidation products trigger cellular processes that up-regulate the overall antioxidant status of the cell, and could be incorporated into treatments of pathological conditions associated with elevated oxidative DNA damage and other manifestations of increased oxidative stress.

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A heat-labile protein has been identified in fruit bodies of the edible mushroom, Agaricus bisporus, which protects Raji cells (a human lymphoma cell line) against H2O2-induced oxidative damage to cellular DNA. This protein has been purified following salt fractionation, combined with ion-exchange, hydrophobic interaction and adsorption chromatography. Based on catalytic and electrophoretic properties, and inhibition studies using tropolone, the protein was identified as tyrosinase.

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Aqueous extracts of the sporophores of eight mushroom species were assessed for their ability to prevent H2O2-induced oxidative damage to cellular DNA using the single-cell gel electrophoresis ("Comet") assay. The highest genoprotective effects were obtained with cold (20 degrees C) and hot (100 degrees C) water extracts of Agaricus bisporus and Ganoderma lucidum fruit bodies, respectively. No protective effects were observed with Mushroom Derived Preparations (MDPs) from Flammulina velutipes, Auricularia auricula, Hypsizygus marmoreus, Lentinula edodes, Pleurotus sajor-caju, and Volvariella volvacea.

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