13 results on '"Allen, Stuart C. H."'
Search Results
2. Methods of isolation and identification of pathogenic and potential pathogenic bacteria from skins and tannery effluents
- Author
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Anne Lama, Margaret Bates, Covington, Anthony D., Allen, Stuart C. H., and Antunes, A. Paula M.
- Subjects
QR75 ,TD896 ,TS967 ,TS965.5 - Abstract
Currently there is no standard protocol available within the leather industry to isolate and identify pathogenic bacteria from hides, skins or tannery effluent. This study was therefore carried out to identify simple but effective methods for isolation and identification of bacterial pathogens from the effluent and skins during leather processing. Identification methods based on both phenotypic and genotypic characteristics were investigated. Bacillus cereus and Pseudomonas aeruginosa were used as indicator bacteria to evaluate the isolation and identification methods. Decontaminated calfskins were inoculated with a pure culture of the above mentioned bacterial species followed by a pre-tanning and chromium tanning processes. Effluent samples were collected and skins were swabbed at the end of each processing stage. Bacterial identification was carried out based on the phenotypic characteristics; such as colony appearance on selective solid media, cell morphology following a standard Gram-staining and spore staining techniques, and biochemical reactions, e.g., the ability of a bacterial species to ferment particular sugars and ability to produce certain enzymes. Additionally, an identification system based on bacterial phenotypic characteristics, known as Biolog® system was applied. A pulsed-filed gel electrophoresis (PFGE) method for bacterial DNA fingerprinting was also evaluated and used for the identification of the inoculated bacteria. The methods described in the study were found to be effective for the identification of pathogenic bacteria from skins and effluent.
- Published
- 2013
3. The impact of beamhouse processes on bacterial growth
- Author
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Lama, Anne, Allen, Stuart C H, Attenburrow, Geoff E, Bates, Margaret P, Covington, Anthony D, Antunes, A Paula M, Lama, Anne, Allen, Stuart C H, Attenburrow, Geoff E, Bates, Margaret P, Covington, Anthony D, and Antunes, A Paula M
- Abstract
Various bacterial species including potential pathogens have been isolated from hides and skins. During conventional leather processing, due to the extreme environmental conditions, the probability of bacteria surviving on hides is reduced. Alternatively, total or partial replacement of the hazardous chemicals with nonhazardous chemicals during best available technologies (BAT) processes may provide suitable conditions for bacterial growth. The aim of the present work was to determine the effect of conventional and BAT beamhouse operations on certain bacterial species. Decontaminated calf skin samples were inoculated with a known bacterial species found in hides or skins. A conventional and BAT beamhouse processes was carried out with inoculated skin samples, and bacterial growth was determined at various stages of beamhouse through microbial analysis. Analysis of the bacteria during the beamhouse operations showed that some of the stages of the beamhouse process inhibited the bacterial growth whilst other stages promoted the growth of bacteria.
- Published
- 2009
4. Folding-competent and Folding-defective Forms of Ricin A Chain Have Different Fates after Retrotranslocation from the Endoplasmic Reticulum
- Author
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Li, Shuyu, primary, Spooner, Robert A., additional, Allen, Stuart C. H., additional, Guise, Christopher P., additional, Ladds, Graham, additional, Schnöder, Tina, additional, Schmitt, Manfred J., additional, Lord, J. Michael, additional, and Roberts, Lynne M., additional
- Published
- 2010
- Full Text
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5. Utilisation of the budding yeastSaccharomyces cerevisiae for the generation and isolation of non-lethal ricin A chain variants
- Author
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Allen, Stuart C. H., primary, Byron, Adam, additional, Lord, J. Michael, additional, Davey, John, additional, Roberts, Lynne M., additional, and Ladds, Graham, additional
- Published
- 2005
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6. Utilisation of the budding yeast Saccharomyces cerevisiae for the generation and isolation of non-lethal ricin A chain variants.
- Author
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Allen, Stuart C. H., Byron, Adam, Lord, J. Michael, Davey, John, Roberts, Lynne M., and Ladds, Graham
- Abstract
Knowledge of the uptake, membrane translocation, refolding and ribosome interaction of the ribosome-inactivating toxin ricin is incomplete at the present time. Ricin A chain (RTA) is the catalytic subunit of holotoxin and is also of particular interest as a vaccine candidate. For many studies into the uptake and immunological applications of ricin, it is essential to have inactive variants. Here, following error-prone polymerase chain reaction of the RTA open reading frame, we have used a modified gap-repair protocol in Saccharomyces cerevisiae to show that it is possible to rapidly generate a panel of inactive RTA mutants. Since yeast cells have ribosomes that are highly sensitive to RTA, we utilized a genetic selection based on the viability of transformants. This enabled the recovery of a number of mutations, some not previously identified, which permitted production of full-length but non-toxic RTA proteins. Such disarmed toxins may have utility as tools to study the cytosolic entry and action of RTA, and as potential vaccine candidates. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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7. Enhancing student employability skills through partnership working in STEM outreach: the University of Northampton approach
- Author
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John Mitchell Sinclair, Allen, Stuart C. H., Linda Davis, Tricia Goodchild, Julie Messenger, and Scott Turner
- Subjects
ComputingMilieux_COMPUTERSANDEDUCATION - Abstract
For over a decade, University of Northampton staff and students have delivered successful STEM outreach activities, master classes and co-working opportunities to learners in schools and FE colleges. In addition, the University works with the local STEMNET contract holder to gain national recognition for staff and students STEM Ambassadors and recognises STEM Ambassadors through awards (staff and student) as part of its annual celebration of volunteer achievement. Both developments derive from a culture of empowering students as partners and enhancing the student journey. The University has developed a co-ordinated programme of training and events to empower students and staff to engage with school and community outreach. A cross-University STEM Steering Group (SSG) which features both management and grass roots-level representation from the across the University (Science and Technology, Health, Education, the Arts and its Centre for Employability and Engagement) manages the activities, including recruiting representation from the student body. As such, SSG is uniquely well-placed to champion STEM activities across the University and to make these available to the wider community. Local schools are able to access inspirational science activities, whilst University students gain employability-related skills in leadership, communication, project-delivery and self-motivation and staff gain valuable CPD. Students also identify more strongly with the University. The total package plays a major role in contributing to University aspirations in widening participation and is hugely popular with participants. This paper will outline the project and will showcase the positive enhancements which it offers to University of Northampton students and school participants.
8. An ethnographic study of palliative care in a Nigerian hospital
- Author
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Agom, David, Neill, Sarah Jane, Allen, Stuart C. H., and Poole, Helen Louise
- Subjects
362.17 ,Nigeria ,palliative care ,ethnography ,nursing - Abstract
Palliative care has become an important public health issue in recent years and has been declared a universal human right. A wealth of literature can be found describing its effectiveness and numerous benefits, yet significant disparities exist in worldwide palliative care development between, and within, countries. To date, previous studies indicate that it has steadily improved in the more economically developed countries, although its utilisation remained uneven in western societies between the blacks compared with the white people. In low- and middle-income countries, palliative care has continued to be less available, underutilised and not integrated in many of the healthcare systems, especially in the African countries such as Nigeria. This qualitative study using an ethnographical approach to understand the cultural, socio-political, environmental, and organisational dynamics which influenced the provision of palliative care, and the patients' and relatives' behaviour towards its utilisation in a Nigerian hospital. Data was collected using participant observation, ethnographic interview and review of documentary sources, involving 43 participants, comprising healthcare professionals, members of the hospital management, patients and their families. The findings show a dominant discourse of culturally-based perceptions rooted in belief systems and inadequate knowledge of palliative care associated with insufficient education and training which manifested in several ways, such as conceptualisation of palliative care as a 'dead end'. The service-users predominantly used their belief systems in decision-making, whereas dichotomy existed amongst the professionals about using either ethno-religious knowledge or biomedical knowledge to inform practice. These culturally-based perceptions were found to be contributory to, and a result of, a political and organisational culture that did not value palliation. Thus, the insensitivity of the bureaucrats was displayed in numerous ways, such as lack of funding for palliative care. Consequently, the environment for care represented space rather than a place that could promote the wellbeing of the service-users, which thereby contributed to various organisational cultures, such as weak interdepartmental collaboration and work-stoppage, with negative impacts for the service-users. The findings also suggest that the customary code of behaviour used by the service users was conditioned mainly by complex interactions of economic conditions, social relationships and lack of a governmental social support system. The professionals, therefore, used their personal resources as well as provided physical cash to the patients to cushion the effect of government inadequacies and to improve their wellbeing. These findings indicate the need for a cultural shift towards a mind-set that values palliative care in Nigeria in order to enhance its development. This study adds to the knowledge of this field and provides clinicians around the world with further understanding of meaning making in illness from the perspective of the Nigerian culture, which may be applicable to other people of African ancestry and could be used to boost cultural competence in palliative care.
- Published
- 2019
9. The phenotypic and molecular responses of Listeria monocytogenes to stressors
- Author
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Sewell, Danny, Phillips, Carol A., and Allen, Stuart C. H.
- Subjects
616 ,QR46 Medical microbiology ,QR115 Food microbiology ,QR201.L7 Listeriosis - Abstract
Listeria monocytogenes is a food-borne pathogen and the causative agent of listeriosis, a severe infection resulting in septicaemia, meningitis and still birth. Infection typically arises through the consumption of contaminated foodstuffs. L. monocytogenes is a hardy organism which can survive several food control measures. Psychotrophic and facultatively anaerobic properties permit growth under refrigeration conditions and within modified atmosphere packaging. Through transcriptional and translational changes L. monocytogenes is able to mount adaptive responses against stressors. Such responses typically cross protect against subsequent stresses, including effectors of the human immune system. The aim of this study was to assess the ability of L. monocytogenes to adaptively respond to stressors, and to assess the phenotypic and molecular responses that such exposures have on resistance and virulence potential. Using adaptation and repeated exposure assays L. monocytogenes cells were assessed for their ability to develop resistance and to adaptively respond to stressors. Using qRT-PCR and insertional mutagenesis the roles of several candidate genes in stress response were assessed. Using a simulated gastro-intestinal transit model the effects of refrigeration and oxygen limitation on virulence potential were investigated, while microarray analysis allowed elucidation of the molecular mechanisms accounting for altered resistance properties and virulence potential. Stationary phase L. monocytogenes cells were not found to adapt to sub lethal exposure to citric acid, TSP, NaCIO and H2O2. Susceptibility to stressors was increased or unchanged following sub-lethal pre-exposure. Sub-lethal exposure to NaCIO increased expression of Imo0669 (oxidoreductase) by 4.6-fold, while a 2-fold increase in gadA was observed during TSP exposure. These responses permit survival under NaCIO and TSP stress, and may have implications in subsequent stress exposure and/or virulence potential. Inactivation of ctsR, hfq, lisR and lisK by site-directed mutagenesis gave rise to mutant cells with increased sensitivity to H2O2. Citric acid resistance was impaired by ctsR and hfq disruption. Pre-conditioning under oxygen limiting conditions significantly increased acid tolerance in L. monocytogenes FSL R2-499. When assessing the effects of pre-conditioning on gastro-intestinal transit L. monocytogenes FSL R2-499 displayed growth phase, pre-conditioning and pH dependant resistance profiles. Cells grown under oxygen limiting conditions typically demonstrated increased resistance towards simulated gastric juice (pH 2.5), however, only stationary phase cells were able to survive bile salt exposure. L. monocytogenes cells grown under oxygen limiting conditions displayed increased acid tolerance but decreased H2O2 resistance. Transcriptional analysis revealed significant up-regulation of the acid response gene, gadA, under oxygen limiting conditions, while catalase was significantly down-regulated. The findings of this study provide important information for food manufacturers who can use this data to "intelligently apply" food control measures, or hurdles, to improve food safety.
- Published
- 2014
10. Investigating physiological and genetic characteristics of community acquired infections and potential antimicrobial interventions
- Author
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Adukwu, Emmanuel, Allen, Stuart C. H., and Phillips, Carol A.
- Subjects
362.1969 ,QR46 Medical microbiology ,RA421 Public health. Hygiene. Preventive Medicine ,QR75 Bacteria - Abstract
Staphylococcus aureus and Enterococcus sp. infections occur in hospital and, increasingly, in community settings, with the potential of having different susceptibility to antimicrobial agents. The purpose of this study was to investigate the effect of antimicrobial agents against community acquired S.aureus and investigate antibiotic characteristics, biofilm formation and gene expression following exposure to an antimicrobial agent. The susceptibility of S. aureus isolates and a vancomycin resistant Enterococcus faecium isolate to antibiotics, essential oils and disinfectants were investigated under planktonic conditions using standardised antimicrobial susceptibility tests and the Quantitative suspension and surface tests (EN 1276 and EN 13697) for the disinfectants. Biofilm formation, inhibition and eradication was investigated using the crystal violet (CV) assay while the viability of treated biofilms were investigated using the 2, 3-bis [2-methyloxy-4-nitro-5- sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay and CFU/ml assay. Multiplex PCR was used to determine the presence of PVL, icaA and IcaD genes as well as SCCmec typing while RT-PCR used to investigate changes in gene expression in five target genes following treatment of PVL CA MSSA and CA MRSA MW2 biofilms with grapefruit EO. The S. aureus isolates all formed biofilms and had similar molecular characteristics however one isolate (CA MRSA SR) was multidrug resistant and PVL negative. The VRE isolate was negative for biofilm formation. In suspension, household bleach and NaDCC caused > 5 log reduction in viable counts and on stainless steel surfaces, there was < 3.5 log reduction. Against biofilms, Household bleach at 5000ppm caused 100% biofilm eradication within 10 minutes while NaDCC eradicated <50% of the biofilm within one hour at 10,000ppm. The eco-friendly product did not demonstrate any antimicrobial activity against planktonic cells or biofilms. Antimicrobial activity of six essential oils (EO) (lime, lemon, lemongrass, geranium, grapefruit, bergamot), and two components (limonene and citral) was investigated for the S. aureus isolates. Following exposure to lemongrass EO extensive disruption to S. aureus biofilms was shown under scanning electron microscopy. The most notable changes in gene expression following exposure to grapefruit EO were the /caD, luxS and sodA genes when the PVL CA MSSA biofilms was compared to the prototype community acquired strain, CA MRSA MW2. The S. aureus isolates were susceptible to the essential oils with the exception of limonene and lemon EO. Lemongrass EO inhibited biofilm formation, metabolic activity and viability. No anti-biofilm activity was observed for Grapefruit EO against S. aureus except for one isolate (PVL positive CA MSSA), where an increase in metabolic activity was observed following treatment. Lemongrass EO was effective as an antibacterial and antibiofilm agent and could be a potential alternative to chemical based antimicrobial agents in both healthcare and non-healthcare environments.
- Published
- 2013
11. Plastic embedding techniques for light microscopy histological studies
- Author
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Hand, Neil M., Raleigh, Stuart M., and Allen, Stuart C. H.
- Subjects
611 - Abstract
This thesis collates, records and reviews pioneering studies performed by the author on the formulation, use, advantages, and applications of acrylic plastic embedding media for the histological examination of tissue using light microscopy, with particular emphasis on histochemical and molecular techniques. Nine key papers by the author are reviewed. The first relates to a number of modifications of an established method for the histological examination and investigation of metabolic bone diseases. As a result it was reported that the procedure had resulted in significant time saving without detrimentally affecting quality, and has been used for investigating approximately 10,000 cases of metabolic bone diseases for diagnosis. In a further separate development, the enzymes lactase and sucrase were first reported in plastic-embedded jejunum. Subsequently it was shown that these two important disaccharidases for assessing malabsorption were sensitive to specific processing agents and could easily be lost, resulting in false negative staining. However, by using a specific processing schedule and times, the author was able to demonstrate how best tissue could be processed to retain these and other enzymes in various plastic embedding media. A number of procedures were initiated for the application of IHC on plastic- embedded tissue that included the development of a modified plastic with new preparatory techniques, and changes in immunocytochemical staining protocols to enable IHC to be routinely performed. Previously, this had been regarded as technically not possible. Later in a series of papers published, procedures were described where the use and evaluation of enzyme, and/or antigen retrieval techniques using microwave heating and/or pressure cooking were assessed. Numerous antigens were successfully demonstrated, and subsequently specific diagnostic applications on various tissues were reported, including extensive routine use on approximately 35,000 cases to date of bone marrow trephines. In a further development, the application of ISH techniques for the detection of mRNA in chick tissue for the demonstration of transcription Sox genes 11 and 21 was reported, which subsequently was combined with IHC for bromodeoxyuridine or neurofilament protein for simultaneous double staining on the same section.
- Published
- 2013
12. Myb induced myeloid protein 1 (Mim-1) is an acetyltransferase.
- Author
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Allen SC and Hebbes TR
- Subjects
- Acetyltransferases isolation & purification, Amino Acid Sequence, Animals, Chickens blood, Conserved Sequence, Erythrocytes enzymology, Molecular Sequence Data, Protein Structure, Tertiary, Sequence Analysis, Sequence Analysis, Protein, Acetyltransferases metabolism
- Abstract
We have screened protein extracts from chicken blood cells for acetyltransferases. An in gel acetyltransferase assay revealed that a 32 kDa protein, which is more prevalent in whole blood when compared with erythrocyte cells, possessed an auto-acetylation activity. This protein was purified by a series of chromatographic steps, sequenced by Edman degradation and subsequently identified as Myb induced myeloid protein (Mim-1). Mim-1 has similarities to the conserved acetyltransferase motifs found in the GNAT superfamily of proteins and also contains three minimal GK acetylation motifs. These data identify Mim-1 as an acetyltransferase.
- Published
- 2003
- Full Text
- View/download PDF
13. Essential cytoplasmic domains in the Escherichia coli TatC protein.
- Author
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Allen SC, Barrett CM, Ray N, and Robinson C
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- Amino Acid Sequence, Arabidopsis metabolism, Arginine chemistry, Binding Sites, Cell Membrane metabolism, Green Fluorescent Proteins, Luminescent Proteins metabolism, Membrane Proteins genetics, Membrane Proteins metabolism, Molecular Sequence Data, Mutagenesis, Site-Directed, Mutation, NADH, NADPH Oxidoreductases metabolism, Oxidoreductases Acting on CH-NH Group Donors, Oxidoreductases, N-Demethylating chemistry, Oxidoreductases, N-Demethylating metabolism, Plasmids metabolism, Protein Binding, Protein Structure, Tertiary, Protein Transport, Recombinant Fusion Proteins metabolism, Sequence Homology, Amino Acid, Subcellular Fractions, Cytoplasm chemistry, Escherichia coli metabolism, Membrane Proteins chemistry, Plant Proteins
- Abstract
The twin-arginine translocation (Tat) system mediates the transport of proteins across the bacterial plasma membrane and chloroplast thylakoid membrane. Operating in parallel with Sec-type systems in these membranes, the Tat system is completely different in both structural and mechanistic terms, and is uniquely able to catalyze the translocation of fully folded proteins across coupled membranes. TatC is an essential, multispanning component that has been proposed to form part of the binding site for substrate precursor proteins. In this study we have tested the importance of conserved residues on the periplasmic and cytoplasmic face of the Escherichia coli protein. We find that many of the mutations on the cytoplasmic face have little or no effect. However, substitution at several positions in the extreme N-terminal cytoplasmic region or the predicted first cytoplasmic loop lead to a significant or complete loss of Tat-dependent export. The mutated strains are unable to grow anaerobically on trimethylamine N-oxide minimal media and are unable to export trimethylamine-N-oxide reductase (TorA). The same mutants are completely unable to export a chimeric protein, comprising the TorA signal peptide linked to green fluorescent protein, indicating that translocation is blocked rather than cofactor insertion into the TorA mature protein. The data point to two essential cytoplasmic domains on the TatC protein that are essential for export.
- Published
- 2002
- Full Text
- View/download PDF
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