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Search Results: 1 - 10 of 448 matches for " Aidan Coffey "
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Transcriptome analysis of Listeria monocytogenes exposed to biocide stress reveals a multi-system response involving cell wall synthesis, sugar uptake, and motility
Aidan Casey,Edward M. Fox,Stephan Schmitz-Esser,Aidan Coffey,Olivia McAuliffe,Kieran Jordan
Frontiers in Microbiology , 2014, DOI: 10.3389/fmicb.2014.00068
Abstract: Listeria monocytogenes is a virulent food-borne pathogen most often associated with the consumption of “ready-to-eat” foods. The organism is a common contaminant of food processing plants where it may persist for extended periods of time. A commonly used approach for the control of Listeria monocytogenes in the processing environment is the application of biocides such as quaternary ammonium compounds. In this study, the transcriptomic response of a persistent strain of L. monocytogenes (strain 6179) on exposure to a sub-lethal concentration of the quaternary ammonium compound benzethonium chloride (BZT) was assessed. Using RNA-Seq, gene expression levels were quantified by sequencing the transcriptome of L. monocytogenes 6179 in the presence (4 ppm) and absence of BZT, and mapping each data set to the sequenced genome of strain 6179. Hundreds of differentially expressed genes were identified, and subsequent analysis suggested that many biological processes such as peptidoglycan biosynthesis, bacterial chemotaxis and motility, and carbohydrate uptake, were involved in the response of L. monocyotogenes to the presence of BZT. The information generated in this study further contributes to our understanding of the response of bacteria to environmental stress. In addition, this study demonstrates the importance of using the bacterium's own genome as a reference when analysing RNA-Seq data.
Isolation and detection of Mycobacterium avium subsp. paratuberculosis (MAP) from cattle in Ireland using both traditional culture and molecular based methods
Pierre E Douarre, William Cashman, Jim Buckley, Aidan Coffey, Jim M O'Mahony
Gut Pathogens , 2010, DOI: 10.1186/1757-4749-2-11
Abstract: M. paratuberculosis was isolated and cultured from 23 faecal samples (7.9%) on solid medium. From a molecular perspective, 105 faecal samples (36%) were PCR positive for MAP specific DNA. A complete correlation (100%) was observed between the results of both molecular targets (IS900 and ISMAP02). Sensitivity was increased by ~10% with the inclusion of a nested PCR for ISMAP02 (29 further samples were positive). When culturing and PCR were retrospectively compared, every culture positive faecal sample also yielded a PCR positive result for both targets. Alternatively, however not every PCR positive sample (n = 105, 36%) produced a corresponding culture isolate. Interestingly though when analysed collectively at the herd level, the correlation between culture and PCR results was 100% (ie every herd which recorded at least 1 early PCR +ve result later yielded culture positive samples within that herd).PCR on bovine faecal samples is a fast reliable test and should be applied routinely when screening for MAP within herds suspected of paratuberculosis. Nested PCR increases the threshold limit of detection for MAP DNA by approximately 10% but proved to be problematic in this study. Although slow and impractical, culturing is still regarded as one of the most reliable methods for detecting MAP among infected cattle.Johne's disease caused by Mycobacterium avium subsp. paratuberculosis (MAP), is one of the most widespread and economically important disease of ruminants. It is a chronic granulomatous enteritis affecting primarily ruminants and many other species [1], which is characterised by persistent diarrhoea, weight loss and a protein enteropathy, followed eventually by death [2]. Most cattle are infected early in life by the ingestion of faeces, milk or MAP contaminated water. The relatively long incubation period is characterized by the excretion of MAP in faeces for months and years before clinical symptoms develop [3]. The exposure to contaminated faeces constitutes
Bacteriophage-Derived Peptidase Eliminates and Prevents Staphylococcal Biofilms
Mark Fenton,Ruth Keary,Olivia McAuliffe,R. Paul Ross,Jim O'Mahony,Aidan Coffey
International Journal of Microbiology , 2013, DOI: 10.1155/2013/625341
Abstract: New antibacterial agents are urgently needed for the elimination of biofilm-forming bacteria that are highly resistant to traditional antimicrobial agents. Proliferation of such bacteria can lead to significant economic losses in the agri-food sector. This study demonstrates the potential of the bacteriophage-derived peptidase, , as a biocidal agent for the rapid disruption of biofilm-forming staphylococci, commonly associated with bovine mastitis. Purified applied to biofilms of Staphylococcus aureus DPC5246 completely eliminated the staphylococcal biofilms within 4?h. In addition, was able to prevent biofilm formation by this strain. The lysin also reduced S. aureus in a skin decolonization model. Our data demonstrates the potential of as a biocidal agent for prevention and treatment of biofilm-associated staphylococcal infections or as a decontaminating agent in the food and healthcare sectors. 1. Introduction Staphylococcal species commonly colonise the skin and mucosal membranes of both humans and animals. They are a significant causative agent of bovine mastitis in dairy herds [1] and are also associated with a number of diseases in humans, ranging from a variety of skin conditions to more serious infections such as septicemia [2]. Staphylococcal food poisoning is among the most common food-borne microbial diseases [3] and contamination of food industrial surfaces with staphylococcal species has been demonstrated to be a considerable risk factor [4–6]. Along with the urgent requirement for novel antibacterials to combat the prevalence of antibiotic/disinfectant resistant staphylococci in food processing, veterinary and healthcare settings, there is an increasing need for effective antimicrobial agents which can prevent and treat staphylococcal biofilm-associated infections [7–11]. Biofilms are multilayered communities of sessile cells protected by an extracellular matrix, which often adhere to food contact surfaces, damaged tissue and indwelling medical devices [12–14]. Once formed, biofilms may be up to 1,000 times more resistant to antimicrobial agents than planktonic cells alone making them particularly difficult to eliminate [15]. This can ultimately lead to increased risk of persistent infections, as is commonly the case with bovine mastitis [16]. In addition, because of their increased levels of resistance, biofilm-associated infections can result in a need for explantation of medical devices in human healthcare settings [17, 18]. Although the precise mechanisms of biofilm antibiotic resistance have yet to be fully resolved, failure to
Bacteriophages and Their Derivatives as Biotherapeutic Agents in Disease Prevention and Treatment
Mohamed Elbreki,R. Paul Ross,Colin Hill,Jim O'Mahony,Olivia McAuliffe,Aidan Coffey
Journal of Viruses , 2014, DOI: 10.1155/2014/382539
Abstract: The application of bacteriophages for the elimination of pathogenic bacteria has received significantly increased attention world-wide in the past decade. This is borne out by the increasing prevalence of bacteriophage-specific conferences highlighting significant and diverse advances in the exploitation of bacteriophages. While bacteriophage therapy has been associated with the Former Soviet Union historically, since the 1990s, it has been widely and enthusiastically adopted as a research topic in Western countries. This has been justified by the increasing prevalence of antibiotic resistance in many prominent human pathogenic bacteria. Discussion of the therapeutic aspects of bacteriophages in this review will include the uses of whole phages as antibacterials and will also describe studies on the applications of purified phage-derived peptidoglycan hydrolases, which do not have the constraint of limited bacterial host-range often observed with whole phages. 1. Bacteriophage History Bacteriophages (phages) were first characterised about 100 years ago by [1–3]. Earlier authors, such as Ernest Hankin [4], Nikolay Gamaleya [5], and Frederick Twort [6], are understood to have observed the antibacterial activity of phages without being able to recognise or identify the agents responsible. Nowadays, most recognition for the development of phage therapy goes to Felix d’Herelle who isolated these agents from the stool samples of dysentery patients, named them bacteriophages, and developed the phage assays which remain in use up to the present [7, 8]. He also initiated the first phage therapy experiments in the early 1920s. Research in phage therapy was eclipsed in the West by the advent and increasing widespread successful application of antibiotics in medical practice from the late 1940s. Phage therapy, on the other hand, was declined largely due to variable and unpredictable results, an issue related to the relatively poor understanding of phage biology at the time. Certainly, many of the illnesses that had been treated with phage preparations up to the mid-twentieth century were likely to have not had a bacterial basis. Thus, the results of phage therapy generally tended to be inferior to those observed for antibiotics, since the latter had a broader therapeutic spectrum and, generally, did not require detailed bacteriological knowledge for effective prescribing by practitioners. The use of phages to treat bacterial infections has recently gained attention in Western medicine mainly due to ever-increasing incidence of bacterial resistance to antibiotics
N-Substituted 5-Amino-6-methylpyrazine-2,3-dicarbonitriles: Microwave-Assisted Synthesis and Biological Properties
Ondrej Jandourek,Martin Dolezal,Pavla Paterova,Vladimir Kubicek,Matus Pesko,Jiri Kunes,Aidan Coffey,Jiahui Guo,Katarina Kralova
Molecules , 2014, DOI: 10.3390/molecules19010651
Abstract: In this work a series of 15 N-benzylamine substituted 5-amino-6-methyl-pyrazine-2,3-dicarbonitriles was prepared by the aminodehalogenation reactions using microwave assisted synthesis with experimentally set and proven conditions. This approach for the aminodehalogenation reaction was chosen due to its higher yields and shorter reaction times. The products of this reaction were characterized by IR, NMR and other analytical data. The compounds were evaluated for their antibacterial, antifungal and herbicidal activity. Compounds 3 (R = 3,4-Cl), 9 (R = 2-Cl) and 11 (R = 4-CF 3) showed good antimycobacterial activity against Mycobacterium tuberculosis (MIC = 6.25 μg/mL). It was found that the lipophilicity is important for antimycobacterial activity and the best substitution on the benzyl moiety of the compounds is a halogen or trifluoromethyl group according to Craig’s plot. The activities against bacteria or fungi were insignificant. The presented compounds also inhibited photosynthetic electron transport in spinach chloroplasts and the IC 50 values of the active compounds varied in the range from 16.4 to 487.0 μmol/L. The most active substances were 2 (R = 3-CF 3), 3 (R = 3,4-Cl) and 11 (R = 4-CF 3). A linear dependence between lipophilicity and herbicidal activity was observed.
Enhanced expression of codon optimized Mycobacterium avium subsp. paratuberculosis antigens in Lactobacillus salivarius
Christopher D. Johnston,John P. Bannantine,Daniel Pletzer,Helge Weingart,Aidan Coffey,Jim O'Mahony,Roy D. Sleator
Frontiers in Cellular and Infection Microbiology , 2014, DOI: 10.3389/fcimb.2014.00120
Abstract: It is well documented that open reading frames containing high GC content show poor expression in A+T rich hosts. Specifically, G+C-rich codon usage is a limiting factor in heterologous expression of Mycobacterium avium subsp. paratuberculosis (MAP) proteins using Lactobacillus salivarius. However, re-engineering opening reading frames through synonymous substitutions can offset codon bias and greatly enhance MAP protein production in this host. In this report, we demonstrate that codon-usage manipulation of MAP2121c can enhance the heterologous expression of the major membrane protein (MMP), analogous to the form in which it is produced natively by MAP bacilli. When heterologously over-expressed, antigenic determinants were preserved in synthetic MMP proteins as shown by monoclonal antibody mediated ELISA. Moreover, MMP is a membrane protein in MAP, which is also targeted to the cellular surface of recombinant L. salivarius at levels comparable to MAP. Additionally, we previously engineered MAP3733c (encoding MptD) and show herein that MptD displays the tendency to associate with the cytoplasmic membrane boundary under confocal microscopy and the intracellularly accumulated protein selectively adheres to the MptD-specific bacteriophage fMptD. This work demonstrates there is potential for L. salivarius as a viable antigen delivery vehicle for MAP, which may provide an effective mucosal vaccine against Johne's disease.
Investigating the Activity Spectrum for Ring-Substituted 8-Hydroxyquinolines
Robert Musiol,Josef Jampilek,Jacek E. Nycz,Matus Pesko,James Carroll,Katarina Kralova,Marcela Vejsova,Jim O'Mahony,Aidan Coffey,Anna Mrozek,Jaroslaw Polanski
Molecules , 2010, DOI: 10.3390/molecules15010288
Abstract: In this study, a series of fourteen ring-substituted 8-hydroxyquinoline derivatives were prepared. The synthesis procedures are presented. The compounds were analyzed using RP-HPLC to determine lipophilicity. They were tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Primary in vitro screening of the synthesized compounds was also performed against four mycobacterial strains and against eight fungal strains. Several compounds showed biological activity comparable with or higher than the standards isoniazid or fluconazole. For all the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed.
Ring-substituted 4-Hydroxy-1H-quinolin-2-ones: Preparation and Biological Activity
Josef Jampilek,Robert Musiol,Matus Pesko,Katarina Kralova,Marcela Vejsova,James Carroll,Aidan Coffey,Jacek Finster,Dominik Tabak,Halina Niedbala,Violetta Kozik,Jaroslaw Polanski,Jozef Csollei,Jiri Dohnal
Molecules , 2009, DOI: 10.3390/molecules14031145
Abstract: In the study, a series of twelve ring-substituted 4-hydroxy-1H-quinolin-2-one derivatives were prepared. The procedures for synthesis of the compounds are presented. The compounds were analyzed using RP-HPLC to determine lipophilicity and tested for their photosynthesis-inhibiting activity using spinach (Spinacia oleracea L.) chloroplasts. All the synthesized compounds were also evaluated for antifungal activity using in vitro screening with eight fungal strains. For all the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed, as well as their structure-activity relationships (SAR).
Investigating the Spectrum of Biological Activity of Ring-Substituted Salicylanilides and Carbamoylphenylcarbamates
Jan Otevrel,Zuzana Mandelova,Matus Pesko,Jiahui Guo,Katarina Kralova,Frantisek Sersen,Marcela Vejsova,Danuta S. Kalinowski,Zaklina Kovacevic,Aidan Coffey,Jozef Csollei,Des R. Richardson,Josef Jampilek
Molecules , 2010, DOI: 10.3390/molecules15118122
Abstract: In this study, a series of twelve ring-substituted salicylanilides and carbamoylphenylcarbamates were prepared and characterized. The compounds were analyzed using RP-HPLC to determine lipophilicity. They were tested for their activity related to the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Moreover, their site of action in the photosynthetic apparatus was determined. Primary in vitro screening of the synthesized compounds was also performed against mycobacterial, bacterial and fungal strains. Several compounds showed biological activity comparable with or higher than the standards 3-(3,4-dichlorophenyl)-1,1-dimethylurea, isoniazid, penicillin G, ciprofloxacin or fluconazole. The most active compounds showed minimal anti-proliferative activity against human cells in culture, indicating they would have low cytotoxicity. For all compounds, the relationships between lipophilicity and the chemical structure are discussed.
Investigating Biological Activity Spectrum for Novel Styrylquinazoline Analogues
Josef Jampilek,Robert Musiol,Jacek Finster,Matus Pesko,James Carroll,Katarina Kralova,Marcela Vejsova,Jim O'Mahony,Aidan Coffey,Jiri Dohnal,Jaroslaw Polanski
Molecules , 2009, DOI: 10.3390/molecules14104246
Abstract: In this study, series of ring-substituted 2-styrylquinazolin-4(3H)-one and 4-chloro-2-styrylquinazoline derivatives were prepared. The syntheses of the discussed compounds are presented. The compounds were analyzed by RP-HPLC to determine lipophilicity. They were tested for their inhibitory activity on photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Primary in vitro screening of the synthesized compounds was also performed against four mycobacterial strains and against eight fungal strains. Several compounds showed biological activity comparable with or higher than that of the standard isoniazid. It was found that the electronic properties of the R substituent, and not the total lipophilicity of the compound, were decisive for the photosynthesis-inhibiting activity of tested compounds.
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