Browsing by Author "Watson, David G."

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    The Chemical and Biological Properties of Propolis
    (Springer, Cham, 2017) Siheri, Weam; Alenezi, Sameah; Tusiimire, Jonans; Watson, David G.
    Bees produce several different products which have health benefits. There is no doubt that honey has a highly significant status in medical treatments, while other apian materials, such as wax, royal jelly and propolis, have fewer medical applications, despite the fact that propolis has been used by people since ancient times (Burdock 1998; Ghisalberti 1979). The term propolis comes from two Greek words, (which means for or in defence of) and polis (which means the city); thus propolis means in defence of the city or beehive (Ghisalberti 1979). Propolis is a sticky resinous substance, which is gathered from buds and the bark of trees. It is also known as “bee glue” as bees use it to cover surfaces, seal holes and close gaps in their hives, thus providing a sterile environment that protects them from microbes
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    Metabolomic Profiling of the Effects of Melittin on Cisplatin Resistant and Cisplatin Sensitive Ovarian Cancer Cells Using Mass Spectrometry and Biolog Microarray Technology
    (Metabolites, 2016) Alonezi, Sanad; Tusiimire, Jonans; Wallace, Jennifer; Dufton, Mark J.; Parkinson, John A.; Young, Louise C.; Clements, Carol J.; Park, Jin K.; Jeon, Jong W.; Ferro, Valerie A.; Watson, David G.
    In the present study, liquid chromatography-mass spectrometry (LC-MS) was employed to characterise the metabolic profiles of two human ovarian cancer cell lines A2780 (cisplatin-sensitive)and A2780CR (cisplatin-resistant) in response to their exposure to melittin, a cytotoxic peptide from bee venom. In addition, the metabolomics data were supported by application of Biolog microarray technology to examine the utilisation of carbon sources by the two cell lines. Data extraction with MZmine 2.14 and database searching were applied to provide metabolite lists. Principal component analysis (PCA) gave clear separation between the cisplatin-sensitive and resistant strains and their respective controls. The cisplatin-resistant cells were slightly more sensitive to melittin than the sensitive cells with IC50 values of 4.5 and 6.8 g/mL respectively, although the latter cell line exhibited the greatest metabolic perturbation upon treatment. The changes induced by melittin in the cisplatin-sensitive cells led mostly to reduced levels of amino acids in the proline/glutamine/arginine pathway, as well as to decreased levels of carnitines, polyamines, adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide (NAD+). The effects on energy metabolism were supported by the data from the Biolog assays. The lipid compositions of the two cell lines were quite different with the A2780 cells having higher levels of several ether lipids than the A2780CR cells. Melittin also had some effect on the lipid composition of the cells. Overall, this study suggests that melittin might have some potential as an adjuvant therapy in cancer treatment.
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    A method for the analysis of sugars in biological systems using reductive amination in combination with hydrophilic interaction chromatography and high resolution mass spectrometry
    (Talanta, 2017) Bawazeer, Sami; Muhsen, Ali; Alhawiti, Ali A.; Khalaf, Abedawn; Gibson, Colin; Tusiimire, Jonans; Watson, David G.
    Separation of sugar isomers extracted from biological samples is challenging because of their natural occurrence as alpha and beta anomers and, in the case of hexoses, in their pyranose and furanose forms. A reductive amination method was developed for the tagging of sugars with the aim of it becoming part of a metabolomics work flow. The best separation of the common hexoses (glucose, fructose, mannose and galactose) was achieved when 2H5-aniline was used as the tagging reagent in combination with separation on a ZICHILIC column. The method was used to tag a range of sugars including pentoses and uronic acids. The method was simple to perform and was able to improve both the separation of sugars and their response to electrospray ionisation. The method was applied to the profiling of sugars in urine where a number of hexose and pentose isomers could be observed. It was also applied to the quantification of sugars in post-mortem brain samples from three control samples and three samples from individuals who had suffered from bipolar disorder.