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Dietetics, Nutrition and Biological Sciences

Permanent URI for this collectionhttps://eresearch.qmu.ac.uk/handle/20.500.12289/23

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Author: search.filters.author.Fyfe, LornaHas files: Yes

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    Comparing Manuka and other medical honeys as adjunct to antibiotic therapy against facultative anaerobes
    (Penerbit UKM, 2022-05) Sievers, Justus Thomas Obiajulu; Moffat, Emily; Yusuf, Khadijah; Sarwar, Nabaa; Bowolaksono, Anom; Fyfe, Lorna
    The development of antibiotic resistance in pathogenic bacteria has created a push for new treatments, with honeys (especially Manuka) becoming a common focus due to their strong antimicrobial action. However, alternatives to Manuka are necessary, as its production is vulnerable. Additionally, research is lacking on how honey affect facultative anaerobic bacteria grown in anaerobic conditions and how honey and antibiotics interact in these conditions. In order to understand these interactions and find novel honey candidates, we investigated the antibacterial effects of four honeys (two Manuka, one Chilean and one ‘Santa Cruz’ honeydew honey) against Staphylococcus aureus and Pseudomonas aeruginosa grown aerobically and anaerobically in broth cultures, and how the honeys affected the action of common antibiotics against these bacteria using agar diffusion assays. We found all honeys to be highly effective at 75% honey, with no significant differences between honeys, showing that other honeys were suitable alternatives to Manuka at such high concentrations. At 20%, oxygen availability and bacterial species impacted the effectiveness of honeys as Santa Cruz honey was most effective aerobically but failed anaerobically, while Manuka honeys were effective against S. aureus but not P. aeruginosa in both conditions, and Chilean honey was ineffective against all samples. The addition of honey increased bacterial sensitivity to antibiotics in some cases, varying with aerobic conditions. The antibacterial activity of the honeys, and differences in conditions whether aerobically or anaerobically, were not correlated with pH, antioxidant capacity or total phenolic count. Since in all cases honeys were either beneficial or of no effect, these results supported the use of honey as adjunct to antibiotic therapy in scenarios such as on bandages, with honeys other than Manuka also being worth consideration.
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    Honey combination therapies for skin and wound infections: A systematic review of the literature
    (Dove Medical Press, 2020-11-24) McLoone, Pauline; Tabys, Dina; Fyfe, Lorna
    Topical application of medical grade honey is recommended for the clinical management of wound infections. The suitability of honey as a wound healing agent is largely due to its antibacterial activity, immune modulatory properties, and biocompatibility. Despite the usefulness of honey in wound healing, chronic wound infections continue to be a global problem requiring new and improved therapeutic interventions. Several recent studies have investigated the effects of combining honey with other therapies or agents with the aim of finding more efficacious treatments. In this systematic review, the database PubMed was used to carry out a search of the scientific literature on the combined effects of honey and other therapies on antimicrobial activity and wound and skin healing. The search revealed that synergistic or additive antimicrobial effects were observed in vitro when honey was combined with antibiotics, bacteriophages, antimicrobial peptides, natural agents e.g. ginger or propolis and other treatment approaches such as the use of chitosan hydrogel. Outcomes depended on the type of honey, the combining agent or treatment and the microbial species or strain. Improved wound healing was also observed in vivo in mice when honey was combined with laser therapy or bacteriophage therapy. More clinical studies in humans are required to fully understand the effectiveness of honey combination therapies for the treatment of skin and wound infections.
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    Inhibition and changes in antibiotic sensitivity of bacteria cultured aerobically and anaerobically in four different medicinal honeys
    (eScientific, 2020-03-27) Klein, Juan-Pablo; Graves-Morris, Katherine; Coyle, Shirley; Fyfe, Lorna
    The growing prevalence of bacterial antibiotic resistance has led to a rediscovery of the antimicrobial properties of honey. This study investigated the antibacterial activity in aerobic and anaerobic conditions, the effect on bacterial antibiotic sensitivity, and the composition of four medical-grade honeys Medihoney®, Comvita® Antibacterial Wound Gel™, Revamil® gel, and Surgihoney™RO®.A broth assay was used to assess the antibacterial activity of the honeys against Staphylococcus aureus and Pseudomonas aeruginosa in aerobic and anaerobic conditions. A disk diffusion test was used to investigate the effect of exposure to a subinhibitory concentration of the honeys to the sensitivity of bacteria to a range of antibiotics. The composition of each honey was characterised by measuring: sugar content, pH, hydrogen peroxide activity, total polyphenolic content and antioxidant capacity.The honeys differed widely in antibacterial activity. Medihoney® was the most effective reducing the growth of both bacteria to < 1 compared to 9 log10 cfu/mL in the growth controls at all tested concentrations. Revamil® gel was the least active of the honeys only having a negligible effect on bacterial growth at the 25% honey concentration. All honeys were equally or more active in anaerobic conditions than in aerobic conditions. The polyphenolic content may influence the activity of honey. Various honey-antibiotic combinations were identified that enhanced antibiotic sensitivity in bacteria. More research is needed to clarify the role of polyphenols in honey activity and further explore the potential synergies between the honeys and antibiotics.
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    Phenotypic changes in the lipopolysaccaride of Pseudomonas aeruginosa and E.coli grown in milk-based enteral nutrient solutions
    (Elsevier, 1999-01) Hodgson, Ian; Stewart, John; Fyfe, Lorna
    Previous studies have shown enteral nutritional solutions (ENS) contaminated with large numbers of microorganisms from the environment or gastrointestinal (GI) tract of patients have caused respiratory infections, acute and chronic enteritis, and septicemia. The introduction of closed- enteral feeding systems has been used to prevent contaminating organisms from entering enteral feeding systems in large numbers. However, there is some discussion as to whether this has been an effective measure in reducing ENS-related infections because there is anecdotal evidence to suggest that disease processes resulting from enteral feeding are still commonplace in the hospital and home. This is because there is very little information about the growth of microorganisms in ENS and whether growth in ENS may affect the virulence and pathogenicity of microorganisms. This study shows that Escherichia coli and Pseudomonas aeruginosa may grow at 25C from either high or low initial numbers to up to 9.2 log colony-forming units per mL in a range of milk-based ENS. However, these organisms did not grow in the fruit-based ENS. The effect on the lipopolysaccharide (LPS) of culturing E. coli and P. aeruginosa in milk-based ENS as opposed to standard laboratory media was examined using polyacrylamide gel electrophoresis. We found that there were significant qualitative changes in the phenotype of O-polysaccharide side chains of the LPS from these organisms. O-polysaccharide is known to mediate in the complement, antibiotic and bile resistance, and affect adherence. Therefore, changes in the virulence and pathogenicity of these microorganisms when cultured in ENS may be indicated. Thus, the study provides further evidence for reevaluating the microbiologic and immunologic effects of enteral feeding, especially on the microbial flora of the GI tract.
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    A Randomised Double Blind Placebo Controlled Trial of a Nucleotide-Containing Supplement Nucell on Symptoms of Participants with the Common Cold - A Pilot Study
    (ECronicon, 2016-05-20) Davidson, Isobel; Fyfe, Lorna
    Objectives: To ascertain whether a nucleotide containing nutritional supplement Nucell attenuates self-reported symptoms of the common cold. Design: A randomised controlled trial. Setting: A University. Participants: Participants with self-reported symptoms of the common cold but otherwise healthy individuals. Intervention: Nucell capsules containing a yeast-based nucleotide preparation or placebo were provided over a 28 day period. Outcome Measures: Subjective ratings of symptoms were recorded by self-administered questionnaires using a nine-point scale. Salivary IgA concentrations were analysed from samples collected during the first 7 days and then at days 14,21 and 28 of supplementation. Total and white blood cell counts were also measured throughout the intervention. Results: Thirty-six participants completed the study. Nineteen received Nucell and 17 received the placebo. The mean age of participants was similar (29.8 + 2.5 in Nucell group v 30.7 + 2.7 in control group) and the time participants had been suffering from cold-related symptoms was not significantly different in each treatment group (2.5 + 0.40 days in Nucell v 2.9 + 0.47 days in control group). Severity of self-reported symptoms was significantly attenuated in the Nucell treated group in the first week of supplementation for questions asked with respect to taste, painful sinuses and earache (p< 0.05). Supplementation with Nucell did not adversely affect total or differential white blood counts. Conclusion: These results suggest that Nucell supplementation administered as a treatment for cold-related symptoms may reduce the severity of specific symptoms particularly in the early infective phase. In conclusion, Nucell supplementation may provide subjective relief of some cold-related symptoms and may be of significant benefit administered as a treatment in participants where sinus pain, earache and diminished taste are common symptoms.
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    Influence of Subinhibitory Concentrations of Honey on Toxic Shock Syndrome Toxin -1 (TSST-1) Production by Two Strains of Staphylococcus Aureus
    (Horizon Research Publishing, 2015-05) Okoro, P.; Coyle, S.; Fyfe, Lorna
    Antibiotic resistant bacteria are a worldwide health concern and it is essential to develop new antimicrobial agents to kill these bacteria and to reduce the use of antibiotics. Staphyloccus aureus (S.aureus) an important medical pathogen is responsible for many wound infections and up to 25% of all strains produce the toxic shock syndrome toxin (TSST-1) which stimulates the release of inflammatory cytokines which cause fever and shock. Here we report on the inhibition of two penicillin resistant TSST-1 producing strains of S.aureus by seven different honeys. Bacterial growth was reduced after 24 hours at 37oC, from 10.0 log 10 in the TSB growth control to less than 1.0 log 10 in Highland, Chilean and Manuka honey. TSST-1 production was reduced from 256ng/ml in the TSB growth control to less than 30 ng/ml in sub inhibitory concentrations of all honeys.
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    Influence of sub-inhibitory concentrations of plant essential oils on the production of enterotoxins A and B and alpha toxin by Staphylococcus aureus
    (Society for General Microbiology, 2004-10) Smith-Palmer, A.; Stewart, J.; Fyfe, Lorna
    The data presented show the ability of subinhibitory concentrations of plant essential oils to influence the production of enterotoxins A and B and alpha-toxin by Staphylococcus aureus. Subinhibitory concentrations of the oils of bay, clove, cinnamon, nutmeg and thyme had no significant effect on the overall quantity of extracellular protein produced. Haemolysis due to alpha-toxin was significantly reduced after culture with all five plant essential oils. This reduction was greatest with the oils of bay, cinnamon and clove. These three oils also significantly decreased the production of enterotoxin A; the oils of clove and cinnamon also significantly decreased the production of enterotoxin B.
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    Inhibition of listeriolypin O and phosphatidylcholine - specific phospholipase C production in Listeria monocytogeres by subinhibitory concentrations of plant essential oils
    (Society for General Microbiology, 2002-07) Smith-Palmer, A.; Stewart, J.; Fyfe, Lorna
    Successful infection by Listeria monocytogenes is dependent upon a range of bacterial extracellular proteins including a cytolysin termed listeriolysin O and phosphatidylcholine-specific phospholipase C. Five plant essential oils--bay, clove, cinnamon, nutmeg and thyme--significantly reduced the production of listeriolysin O by L. monocytogenes. The greatest change was observed after culture with oil of thyme, which reduced haemolysis to 52.1 haemolytic units (HU)/ml compared with 99.8 HU/ml observed with the control. Oil of clove was the only oil that also significantly reduced phosphatidylcholine-specific phospholipase C activity. These changes were observed despite the oils causing no change to the final bacterial concentration or total extracellular protein concentration.
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    The Roles of Opioid Receptors and Agonists in Health and Disease Conditions
    (Maxwell Scientific Organization,, 2011-04-30) Ibegbu, A. O.; Mullaney, I.; Fyfe, Lorna; McBean, Douglas
    Opioid receptors are found in the Central Nervous System (CNS) and are classified as mu (µ), kappa (κ), delta (δ) and sigma (σ) opioid receptors. Opioid receptors belong to the large family of G Protein Coupled Receptors (GPCRs), and have diverse and important physiological roles. The aim of the present review is to discuss the roles played by opioid receptors, their agonists and antagonists in health and disease conditions. Opioid receptors are not uniformly distributed in the CNS and are found in areas concerned with pain, with the highest concentration in the cerebral cortex, followed by the amygdala, septum, thalamus, hypothalamus, midbrain and spinal cord. Activated delta opioid receptors are coupled to Gi1 while activated mu opioid receptors are coupled to Gi3 in neuroblastoma cells. Mu opioid receptors are activated by mu receptor agonists and are coupled through the Gi1 and GoA. Both mu and kappa opioid receptors are coupled via both Gi and Gz and opioid receptors are important targets for thousands of pharmacological agents. GPCRs typically require activation by agonists for their signalling activity to be initiated but some of the GPCRs may display basal or spontaneous signalling activity in the absence of an agonist. The stimulation of these receptors triggers analgesic effects and affects the function of the nervous system, gastrointestinal tract and other body systems. Hundreds of analogs of opioid peptides have been synthesized in an effort to make the compounds more active, selective, and resistant to biodegradation than the endogenous ligands. All these modifications resulted in obtaining very selective agonists and antagonists with high affinity at mu-, delta-, and kappa-opioid receptors, which are useful in further studies on the pharmacology of opioid receptors in a mammalian organism.
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    The Effect of Hypoxia on G Protein Coupled (Opioid) Receptor Gene Expression in Cortical B50 Neurons in Culture
    (Maxwell Scientific Organization,, 2011-04-30) Ibegbu, A. O.; Mullaney, I.; Fyfe, Lorna; McBean, Douglas
    Hypoxia adversely affects cells and tissues, and neuronal cells in particular have been shown to be more susceptible to the injurious effects of hypoxia in which they may begin to die when oxygen supply is reduced or completely eliminated. Opioid receptor agonists have been shown to elicit several central nervous system effects, mediated via G protein-coupled receptors. The aim of this study was to study the effect of hypoxia on G protein coupled receptor gene expression using mu opioid receptor as a case study in cortical neuronal B50 cell lines in culture. The B50 cells were cultured in normoxia (21% O2; 5% CO2) and hypoxia (5% O2; 5% CO2), and were treated with opioid agonists to determine their effects on hypoxia-induced changes. Three opioid agonists {DAMGO(_), DSLET(*) and ICI--199,441(6)}, were administered to the cells as treatment for 48 hours after 48 hours of initial culture for a total of 96 hours of culture in hypoxic conditions at concentrations of 10, 50 and 100 :M. The levels of G-protein coupled receptor (mu opioid) mRNAs were assessed using RT-PCR. The results showed that hypoxia induced morphological changes in B50 cells in hypoxia while the mu opioid RT-PCR mRNA levels showed no appreciable changes in normal, hypoxic and treated cells. The results show that B50 neuronal cells are susceptible to damage and injurious effects of hypoxia, as are most brain cells and the opioid agonist treatments showed there were no changes in the level of mu opioid receptor gene expression due to hypoxia or agonist treatment in neuronal B50 cells in culture.