Hepatitis C Virus “HCV” is the major factor to develop the chronic liver disease. Accurate genotyping is important to decide the choice and duration of therapy. The most common method for the determination of the genotype in HCV is the direct sequencing of the 5’UTR region, CORE, CORE/E1 and NS5B region. The current study is to compare different subgenomic regions for the molecular characterization of genotype 6 in Hong Kong and study the molecular epidemiology by phylogenetic analysis. Ninety-four patients were included in the study from 2006 to 2009. There was no discordant result between different subgenomic regions. The percentage of the patients sequenced from CORE, CORE/E1 and NS5B were 95%, 93% and 78% respectively. All the HCV strains were genotype 6a except two patients were other subtypes of genotype 6. The phylogenetic analysis in the neighbor-joining tree in CORE/E1 and NS5B region can clearly discriminate between the subtypes of genotype 6, however it cannot show in the NJ tree of the CORE region sequences. It is to conclude that CORE/E1 is the best choice both for the characterization of genotype 6 and used for phylogenetic analysis in the study. / published_or_final_version / Microbiology / Master / Master of Medical Sciences

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

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Abstract The antibacterial activities of three Croton species were compared using bioautography and the serial microdilution methods. The methanolic extracts of all the species had low activity against Escherichia coli. The highest activity was observed with Croton megalobotrys against Enterococcus faecalis with a minimal inhibitory concentration (MIC) value of 0.02 mg/ml. Croton steenkapianus extracts were the least active of the species investigated, only managing an MIC value of 0.625 mg/ml against Pseudomonas aeruginosa. Croton megalobotrys leaf powder was serially extracted using solvents of various polarities. The lowest MIC value (0.06 mg/ml) of the serially extracted fractions was observed with acetone against Pseudomonas aeruginosa. The liquid-liquid fractions of the methanol extract of Croton megalobotrys were also tested. The lowest MIC value of 0.02 mg/ml was observed with n-hexane fraction against Enterococcus faecalis. The carbon tetrachloride fraction was further fractionated using column chromatography with silica as the immobile phase. The resulting seven fractions were tested for activity following the bioassay-guided practice, and it emerged that the first three fractions had active compounds against Staphylococcus aureus when the bioautography method was used.

published_or_final_version / Chemistry / Master / Master of Philosophy

No description available.

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