Phenolic Oxidases in Gall Disease of Milicia Species

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dc.contributor.advisorGbewonyo, W. S. K.
dc.contributor.advisorOsei, Y. D.
dc.contributor.advisorAddy, M. E.
dc.contributor.authorDorleku, W.
dc.contributor.otherUniversity of Ghana, College of Basic and Applied Sciences, School of Physical and Mathematical Sciences, Department of Chemistry
dc.date.accessioned2016-03-15T10:41:05Z
dc.date.accessioned2017-10-13T17:36:23Z
dc.date.available2016-03-15T10:41:05Z
dc.date.available2017-10-13T17:36:23Z
dc.date.issued2000-08
dc.descriptionThesis (MPhil.) - University of Ghana, 2000
dc.description.abstractMilicia regia and M . excelsa are inva.lua.iDle plant species in Ghana for their durable timber. Their numbers are however dwindling. Efforts by the forestry department to establish plantations have been unsuccessful due primarily to attack by Phytolyma species, resulting in gall formation. Phenols and phenolic oxidases appear to be important in the defence mechanisms of some plants as well as in wound healing and regulation of growth in these plants. Thus, they may be natural resistance factors of the Phytolyma-induced gall disease of Milicia species. The activities of phenolic oxidases, [polyphenol oxidase (PPO) and peroxidase (PRO)] and the phenolic content in galls and leaves of Milicia species differing in susceptibility to Phytolyma attack were determined. Polyphenol oxidase and peroxidase were also extracted and partially purified from acetone powders prepared from the galls and leaves. The activity of polyphenol oxidase was found to be higher in the leaves of the resistant plants than in the tolerant and susceptible plants. Galls of the seedlings also showed higher activity of the enzyme than in the normal leaves. Similar trends were also observed for the activity of peroxidase in the samples but the differences in activity were insignificant. Phenol and o-dihydroxyphenol contents of galls of seedlings were slightly lower than in the normal leaves. The resistant plants also showed slightly higher phenol content than the tolerant and susceptible plants. The susceptible plants on the other hand appeared to contain slightly higher o-dihydroxyphenol than the resistant plants. Peroxidase and polyphenol oxidase were extracted and partially purified from acetone powders prepared from galls and leaves of the samples. The peroxidase and polyphenol oxidase from the galls were purified 10 and 14-fold, respectively, using gel filtration followed by ion-exchange chromatography. The peroxidase and polyphenol oxidase from the leaves were also purified 37 and 17-fold, respectively, using ion-exchange chromatography followed by gel filtration. The activities of the two enzymes could not be separated as they co-eluted in the same fractions. The purified enzymes from both sources did not oxidize monophenolsen_US
dc.format.extentxi, 98p. : ill.
dc.identifier.urihttp://197.255.68.203/handle/123456789/7860
dc.language.isoenen_US
dc.publisherUniversity of Ghanaen_US
dc.rights.holderUniversity of Ghana
dc.subjectGALL DISEASE
dc.subjectMilicia Species
dc.subjectPolyphenol Oxidase
dc.subjectTimber Plants
dc.subjectPlant Species
dc.titlePhenolic Oxidases in Gall Disease of Milicia Speciesen_US
dc.typeThesisen_US

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