Life Sciences Commons^™

In Vivo Mature Immunological Synapses Forming Smacs Mediate Clearance Of Virally Infected Astrocytes From The Brain, Carlos Barcia, Clare Thomas, James Curtin, Gwendalyn King, Kolja Wawrowsky, Marianela Candolfi, Weidong Xiong, Chunyan Liu, Kurt Kroeger, Olivier Boyer, Jerzy Kupiec-Weglinski, David Klatzmann, Maria Castro, Pedro Lowenstein

Articles

The microanatomy of immune clearance of infected brain cells remains poorly understood. Immunological synapses are essential anatomical structures that channel information exchanges between T cell–antigen-presenting cells (APC) during the priming and effector phases of T cells' function, and during natural killer–target cell interactions. The hallmark of immunological synapses established by T cells is the formation of the supramolecular activation clusters (SMACs), in which adhesion molecules such as leukocyte function-associated antigen 1 segregate to the peripheral domain of the immunological synapse (p-SMAC), which surrounds the T cell receptor–rich or central SMAC (c-SMAC). The inability so far to detect SMAC formation in …

Newly Identified Vitamin K-Producing Bacteria Isolated From The Neonatal Faecal Flora, Gordon Cooke, John Behan, Mary Costello

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Fat-soluble vitamin K is an essential component of the blood clotting process. Menaquinones are the naturally occurring form of vitamin K identified in bacteria. Lipid extracts were made from three bacteria originally isolated from the human neonatal gut and identified as Enterobacter agglomerans, Serratia marcescens and Enterococcus faecium. Following preparative thin layer chromatography (TLC), the lipid extracts were subjected to liquid chromatography-mass spectrometry (LC-MS) analysis. Peak analysis of the LC-MS data showed that the three bacteria produce various forms of menaquinone.

Effect Of Ozone And Calcium Lactate Treaments On Browning And Textured Properties Of Fresh-Cut Lettuce, Daniel Rico, Ana Belen Martin-Diana, Gary Henehan, Jesus Maria Frias, Catherine Barry-Ryan

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The effects of three treatments, 1 mg L⁻¹ ozone at 18–20 °C, 15 g L⁻¹ calcium lactate (CLac) at 50 °C and a combination thereof, were compared on fresh-cut lettuce over 10 days of refrigerated storage. Respiration rate, browning and texture were examined as main quality indicators. The use of ozone produced a significantly (P < 0.05) higher oxygen decline than the use of CLac (from day 3 to day 10). At the end of storage, CLac (alone or combined with ozone) samples had higher oxygen content (∼9%) than ozone samples (∼6%). Enzymatic activity decreased significantly (P < 0.05) in ozone samples. Polyphenol oxidase activity in fresh-cut lettuce treated with ozone (alone or combined with CLac) showed lower values on day 1 (−1) and at the end of storage (g⁻¹) than CLac samples (4000–4800 units g⁻¹). Ozone also reduced peroxidase activity to ∼300 units g⁻¹ after treatment. Finally, pectin methylesterase activity was also reduced with ozone, showing a negative effect on textural properties. Data suggested that …

Fms-Like Tyrosine Kinase 3 Ligand Recruits Plasmacytoid Dendritic Cells To The Brain, James Curtin, Gwendalyn King, Carlos Barcia, Chunyan Liu, Francois Hubert, Carole Guillonneau, Regis Josien, Ignacio Anegon, Pedro Lowenstein, Maria Castro

Articles

The lack of professional afferent APCs in naive brain parenchyma contributes to the systemic immune ignorance to Ags localized exclusively within the brain. Dendritic cells (DCs) appear within the brain as a consequence of inflammation, but no molecular mechanisms accounting for this influx have been described. In this study we demonstrate that Fms-like tyrosine kinase 3 ligand (Flt3L) recruits plasmacytoid DCs (pDCs; >50-fold; p < 0.001) to the brain parenchyma. These pDCs expressed IFN-alpha, the hallmark cytokine produced by pDCs, indicating recruitment and activation in situ of bona fide pDCs within the brain parenchyma. Flt3L did not increase the numbers of conventional DCs, macrophages, or B, T, NK, NKT, or microglial cells within the brain. Our data demonstrate that Flt3L reconstitutes a crucial afferent component of the immune response, namely, professional APCs within the brain parenchyma, and this could counteract the intrinsic systemic immune ignorance to Ags localized exclusively within the brain.

Analysis Of Enzyme, Carbohydrate And Mineral Distribution In The Foot Of Abalone Shellfish., Leanne F. Harris, Nuala O'Byrne-Ring, Helen Lambkin

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No abstract provided.

The Involvement Of Calcium And Map Kinase Signaling Pathways In The Production Of Radiation-Induced Bystander Effects, Fiona Lyng, Paula Maguire, B. Mcclean, C. Seymour, Carmel Mothersill

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Much evidence now exists regarding radiation-induced bystander effects, but the mechanisms involved in the transduction of the signal are still unclear. The mitogen-activated protein kinase (MAPK) pathways have been linked to growth factor-mediated regulation of cellular events such as proliferation, senescence, differentiation and apoptosis. Activation of multiple MAPK pathways such as the ERK, JNK and p38 pathways have been shown to occur after exposure of cells to radiation and a variety of other toxic stresses. Previous studies have shown oxidative stress and calcium signaling to be important in radiation-induced bystander effects. The aim of the present study was to investigate …

Antimicrobial Resistance In Irish Isolates Of Verocytotoxigenic Escherichia Coli (E. Coli)-Vtec., Ciara Walsh, Geraldine Duffy, R. O'Mahoney, I. S. Blair, D. A. Mcdowell

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This study compared the antimicrobial resistance profiles of Escherichia coli O157:H7 isolates (n = 257) recovered from bovine hides, minced beef and human clinical samples in Ireland, to those profiles of a range of Irish non-O157 E. coli (O111 and O26) isolates (n=31) from a variety of clinical and veterinary sources. Four multi-drug resistant (MDR) E. coli O157:H7 food isolates were identified, with resistance to 10 (1 isolate), 6 (1 isolate) and 4 (2 isolates) antimicrobial agents respectively. Two of these isolates (resistant to 7 and 4 antimicrobial classes) were characterised further by molecular methods and found to contain class …

Survival Of Antibiotic Resistant And Antibiotic Sensitive Strains Of E. Coli O157 And E. Coli O26 In Food Matrices., Ciara Walsh, Geraldine Duffy, I. S. Blair, D. A. Mcdowell

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Escherichia coli O157:H7 or E. coli O26, which were AS (antibiotic sensitive), AR (laboratory created antibiotic resistant mutants), or naturally MAR (multi-antibiotic resistant), were inoculated into laboratory media, yoghurt or orange juice and their growth/survival monitored during enrichment at 37 °C or storage at 4 °C. The strains were also inoculated into minced beef and their thermal inactivation (D-values) examined at 55 °C, with and without a prior heat shock at 48 °C. The growth kinetics (lag phases, growth rates) of the VTEC (verocytotoxigenic E. coli), incubated over 24 h at 37 °C in laboratory media, were …

Isolation And Characterization Of Toxin A-Negative, Toxin B-Positive Clostridium Difficile In Dublin, Ireland, Denise Drudy, N. Harnedy, S. Fanning, R. O’Mahony, L. Kyne

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Clostridium difficile is a major cause of infectious diarrhoea in hospitalised patients. Most pathogenic C. difficile strains produce two toxins, A and B; however, clinically relevant toxin A-negative, toxin Bpositive (A– B+ ) strains of C. difficile that cause diarrhoea and colitis in humans have been isolated worldwide. The aims of this study were to isolate and characterise A– B+ strains from two university hospitals in Dublin, Ireland. Samples positive for C. difficile were identified daily by review of ELISA results and were cultured on selective media. Following culture, toxin-specific immunoassays, IMR-90 cytotoxicity assays and PCR were used to analyse …

Comparative Phylogenomics Of Clostridium Difficile Reveals Clade Specificity And Microevolution Of Hypervirulent Strains., Denise Drudy

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No abstract provided.

Characterisation Of Cell Types In Abalone (Haliotis Spp.) Tissues Using Immunohistochemical Techniques, Leanne Harris, Nuala O'Byrne-Ring, Helen Lambkin

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The increasing popularity of abalone as a seafood delicacy has led to the rapid development of abalone aquaculture worldwide. The commercial and economic importance of this industry has resulted in an increasing interest in the biology of this particular shellfish genus. In this study we focus on the identification of structural, functional and proliferative proteins in two species of abalone shellfish, Haliotis discus hannai and Haliotis tuberculata. Monoclonal and polyclonal antibodies that react with proteins in vertebrate and invertebrate tissues were selected and applied to abalone tissues. Cross sections of whole animals were analysed using avidin–biotin immunoperoxidase staining protocols. In …

Horseradish And Soybean Peroxidases: Comparable Tools For Alternative Niches?, Barry Ryan, CiaráN Fagan, Neil Carolan

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Horseradish and soybean peroxidases (HRP and SBP, respectively) are useful biotechnological tools. HRP is often termed the classical plant heme peroxidase, and although it has been studied for decades our understanding has deepened since its cloning and subsequent expression, which has enabled numerous mutational and protein engineering studies. SBP, however, has been neglected until recently; despite offering a real alternative to HRP that actually outperforms it in terms of stability. SBP is now used in numerous biotechnological applications, including biosensors. Review of both is timely. This article summarises and discusses the main insights into the structure and mechanism of HRP, …

Antimicrobial Resistance In Non-Typhoidal Salmonella From Food Sources Colombia: Evidence For An Unusual Plasmid Located Class 1 Integron In Serotypes Typhimurium And Anatum, Ciara Walsh, Rebecca O'Mahoney, Teresa Quinn, Denise Drudy, Paul Whyte, Salim Matar, Seamus Fanning

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Seventy-two isolates representing 18 serotypes recovered from various food samples collected in Colombia were tested for antimicrobial susceptibilities. The collection was further characterized for extended-spectrum cephalosporin, aminoglycoside, and tetracycline resistance markers. Multidrug resistant (MDR) isolates were further investigated for class 1 integrons and were evaluated for the presence of conjugative plasmids along with a determination of the incompatibility group by polymerase chain reaction (PCR). Antibiogram analysis showed that the incidence rate of ceftiofur resistance was moderately high (15%). A similar level of resistance to neomycin and oxytetracycline (11% and 10%, respectively) was also observed. There was a high prevalence of …

Analysis Of The Mouse And Human Acyl-Coa Thioesterase (Acot) Gene Clusters Shows That Convergent, Functional Evolution Results In A Reduced Number Of Human Peroxisomal Acots., Mary Hunt, Anna Rautanen, Maria Westin, Thomas Svensson, Stefan Alexson

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The maintenance of cellular levels of free fatty acids and acyl-CoAs, the activated form of free fatty acids, is extremely important as imbalances in lipid metabolism have serious consequences for human health. Acyl-CoA thioesterases (ACOTs) hydrolyze acyl-CoAs to the free fatty acid and CoASH, and thereby have the potential to regulate intracellular levels of these compounds. We have previously identified and characterized a mouse ACOT gene cluster, comprised of six genes that apparently arose by gene duplications, encoding acyl- CoA thioesterases with localizations in cytosol (ACOT1), mitochondria (ACOT2) and peroxisomes (ACOT3-6). However, the corresponding human gene cluster contains only three …

High-Level Resistance To Moxifloxacin And Gatifloxacin Associated With A Novel Mutation In Gyrb In Toxin-A-Negative, Toxin-B-Positive Clostridium Difficile, Denise Drudy, T. Quinn, R. O'Mahony, L. Kyne, P. O'Gaora, S. Fanning

Articles

OBJECTIVES:

To determine the mechanism of high-level resistance to fluoroquinolone antimicrobials in toxin-A-negative, toxin-B-positive (A- B+) Clostridium difficile isolates.

METHODS:

Following culture 16-23S PCR ribotyping was used to determine genomic relationships between A- B+ C. difficile isolates. Antimicrobial susceptibilities were determined using Etests in the presence and absence of the efflux pump inhibitors reserpine (20 microg/mL), L-phenylalanine-L-arginine-beta-naphthylamide (PAbetaN; 20 microg/mL) and verapamil (100 microg/mL). Genomic regions including the quinolone-resistance-determining-region (QRDR) of gyrA and gyrB were amplified and characterized.

RESULTS:

PCR ribotyping profiles identified one major cluster of A- B+ C. difficile, universally resistant to the fluoroquinolones tested (ofloxacin, ciprofloxacin, levofloxacin, …

Whey Permeate As A Bio-Preservative For Shelf Life Maintenance Of Fresh-Cut Vegetables, Ana Belen Martin-Diana, Daniel Rico, Jesus Maria Frias, Jemina Mulcahy, Gary Henehan, Catherine Barry-Ryan

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Whey permeate at different concentrations (0.5%, 1.5% and 3%) was used as natural sanitizing agent in the washing treatment of fresh-cut lettuce and carrots. These treatments were compared with a chlorine 120 ppm widely used in the industry. Microbiological, quality (colour changes, browning-related enzymes, headspace gas composition, textural changes and sensory analysis) and nutritional (ascorbic acid and carotenoids) markers were monitored over 10 days in fresh-cut lettuce and carrot packages stored at 4 °C. Whey permeate at 3% resulted in equivalent or better microbial load reduction than chlorine. Although lower concentration of whey permeate produced minor initial reduction, microbial counts …

Effect Of Calcium Lactate And Heat-Shock On Texture In Fresh-Cut Lettuce During Storage, Ana Belen Martin-Diana, Daniel Rico, Jesus Maria Frias, Gary Henehan, Jemina Mulcahy, J. Barat, Catherine Barry-Ryan

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Textural and microstructural changes in fresh-cut lettuce were analysed over 12 days storage. The vegetable was treated with 120 ppm chlorine and with 15 g/L calcium lactate at room temperature (18–20 °C) and at 50 °C (heat-shock). Texturometer analysis showed that samples washed with calcium lactate had significantly (p > 0.05) higher crispness values than samples washed with chlorine. However the use of 50 °C treatment (heat-shock) gave better textural properties at the end of storage and significantly retarded the softening process, being in agreement with the sensorial results. Cryo-SEM micrographs showed a loss of turgor (shrinkage) of the tissue cells …

Social Software, Groups, And Governance, Michael J. Madison

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Formal groups play an important role in the law. Informal groups largely lie outside it. Should the law be more attentive to informal groups? The paper argues that this and related questions are appearing more frequently as a number of computer technologies, which I collect under the heading social software, increase the salience of groups. In turn, that salience raises important questions about both the significance and the benefits of informal groups. The paper suggests that there may be important social benefits associated with informal groups, and that the law should move towards a framework for encouraging and recognizing them. …