Screening of microbial inhibitors against glycogen synthase kinase-3 in eukar yotic signal transduction system obtained from actinomycetes using a yeast based screening system

Chan, Kai Wai (2005) Screening of microbial inhibitors against glycogen synthase kinase-3 in eukar yotic signal transduction system obtained from actinomycetes using a yeast based screening system. Universiti Malaysia Sabah. (Unpublished)

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Abstract

Screening Glycogen Synthase Kinase-3 (GSK-3) inhibitors is an essential task as GSK- 3 inhibitors could serve as drugs to treat diabetes, Alzheimer's disease and other diseases. In this project, a yeast-based screening system comprises of two mutant yeasts, H10075 and H10079 was used to search for GSK-3 inhibitors. A total of 133 (listed in appendix C) actinomycetes crude extracts which contain secondary metabolites were fustly screened using the mutant yeast H10075 to find out whether they have the potential to inhibit mammalian GSK-3β. The mammalian GSK-3β gene was inserted into a plasmid and the plasmid was transformed into a mutant yeast Saccharomyces cerevisiae. This was done by Professor Tomoko Andoh of Hiroshima University in Japan. All these 133 extracts screened were made from 133 actinomycetes strains isolated from soil samples collected at Danum Valley Conservation Area, Sabah. Of all these 133 extracts screened, only 3 (H11526, H11668 and H11686) were found to be able to inhibit the mammalian GSK-3β in the mutant yeast. Another 6 extracts (H11520, H11888, H11900, H11612, H11635 and H11911) were found to be toxic against the mutant yeast and the rest have no activity against the mutant yeast. Presence or absence of inhibition zones around paper discs loaded with extracts is a mean to detect the presence or absence of GSK-3 inhibitors in this screening system which is based on temperature sensitivity of the yeast. An extract which has the potential to inhibit mammalian GSK-3β will exhibit inhibition zone around paper disc on the screening plate incubated at 37°C but not at 25 °C after 72 hours of incubation. An extract which is toxic to the yeast will exhibit inhibition zones on paper discs on both plates. An extract which shows no activity against the yeast will not show any inhibition zones at all on both plates. The 3 extracts of actinomycetes strains H 11526, H 11668 and H11686 were then screened by using the H10079 mutant yeast based on the same principles above. It was found that these 3 extracts are able to inhibit MCK1, the gene in yeast which is homologous to mammalian GSK-3. It was suggested that these 3 extracts to be further screened by using a screening system based on galactose sensitivity in yeast.

Item Type: Academic Exercise
Uncontrolled Keywords: Alzheimer's disease, Screening Glycogen Synthase Kinase-3, GSK-3 inhibitor, extract, extracts of actinomycete,
Subjects: Q Science > QR Microbiology
Divisions: SCHOOL > School of Science and Technology
Depositing User: MDM SITI AZIZAH IDRIS
Date Deposited: 07 Jan 2014 07:51
Last Modified: 10 Oct 2017 08:25
URI: http://eprints.ums.edu.my/id/eprint/7997

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