^*Author for Correspondence.
Faculty of Science and Technology,
Universiti Kebangsaan Malaysia,
43600 UKM Bangi,
Selangor Darul Ehsan, Malaysia
Tel: 60-3-8921-3862
Fax: 60-3-8925-2698
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Key words: affinity chromatography, Burkholderia pseudomallei, exotoxin, scFv

Abstract.
Burkholderia pseudomallei is the causative agent of melioidosis, a fulminating disease in South East Asia and northern Australia. B. pseudomallei is known to secrete various extracellular products related to its pathogenesis, such as lethal exotoxin, protease and hemolysin. We have attempted to purify the exotoxin as studies have shown it to exhibit necrotic and cytotoxic activities and inhibit cellular protein synthesis. Purification was performed by antibody mediated affinity chromatography using previously generated single chain variable fragments (scFv) towards partially purified B. pseudomallei exotoxin coupled to a diaminodipropylamine column. B. pseudomallei was grown in BHIB + 2% glycerol under static conditions at 37°C for 7 days and crude extract was subjected to the scFv-linked column to capture the exotoxin. SDS-PAGE analysis exhibited a purified protein migrating as a single band bearing a size of approximately 37kDa. N-terminal protein sequencing and further bioinformatics analysis showed that the peptide shared some similarity with a putative decapeptide of the Pseudomonas aeruginosa exotoxin A and is present in both chromosomes 1 and 2 of B. pseudomallei. This suggests that the protein obtained could be the 37 kDa subunit of the B. pseudomallei exotoxin. Selected assays demonstrated that the purified product had no hemolytic, proteolytic or tyrosine phosphatase activity. The purified protein can aid in understanding the role of this virulence factor and serve as a candidate for vaccine development to combat melioidosis.

^*Author for Correspondence.
Department of Molecular Medicine,
Faculty of Medicine,
University of Malaya,
50603 Kuala Lumpur, Malaysia
Tel:603 7967 5740
Fax: 603 7967 4957
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Key words: hypervariable regions, Malaysia, mtDNA, sequence polymorphism

Abstract.
Nucleotide sequence variabilities in the three hypervariable (HV-) regions, HV1, HV2, and HV3, of the noncoding control region of human mitochondrial DNA (mtDNA) from a portion of the Malaysian population were elucidated with the use of polymerase chain reaction (PCR) appropriate gel detection and flourescence based sequencing methodologies. Genomic DNA were extracted from 195 randomly selected individuals (15 samples from each of the 13 ethnicities ranging from of Malay, Chinese, Indian, Punjabi, indigenous Sarawakian, indigenous Sabahan, and Orang Asli ) and nucleotide sequence variabilities in HV1, HV2, and HV3 regions, were determined. These were located in the control region that contains sequences responsible for transcription and replication control of the mtDNA. The control region is located between the tRNA genes that encoded proline and phenylalanine, respectively. We found that the noncoding segments of the control region were polymorphic in the Malaysian samples. The polymorphisms within the control region exhibited a significant degree of diversity, thus enabling the three HV-regions of the control region of mtDNA to be used as additional markers in individual identification in forensic investigations, supplementing nuclear DNA markers. The results generated could also further complement anthropology and population studies in Asia.

^*Author for Correspondence.
Dept. of Food Science and Technology,
Sejong University, 98 Kunja-dong,
Kwangjin-ku, Seoul 143-747, Korea.
Tel : 822-3408-3229
Fax : 822-3408-3569
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Key words: Panax ginseng C.A. Meyer, adventitious root, saponin, culture condition, elicitor

Abstract.
Root growth and saponin production in the root culture of Panax ginseng C. A. Meyer were investigated under various pH values, concentrations of sucrose, nitrogen and phosphate and elicitors. The pH of a medium did not have a significant effect on root growth, but apparently affected the saponin content. The maximum saponin content of 0.26 % was obtained at pH 6.0. The optimal concentrations of sucrose, nitrogen and phosphate on root growth and saponin production were 30 g/l, 382.7 mg/l and 40.40 mg/l, respectively. Saponin biosynthesis was stimulated by the addition of panaxatriol saponin (PTS) and total saponin (TS). However, fresh weight in PTS was so low that the theoretical total saponin in TS treatment was higher than that in PTS treatment. Thus, it appears that TS is a better elicitor than PTS in the ginseng root culture. The saponin content in TS treated ginseng root was 0.38 % and approximately 1.5-fold higher than the control. This work will be helpful for efficient large-scale bioprecessing of the ginseng root culture in a bioreactor.

^*Author for Correspondence.
Dept. Medical Microbiology & Immunology, Faculty of Medicine, UKM
Jalan Yaacob Latiff, 56000 Kuala Lumpur, Malaysia.
Tel: 603-91702208; Fax: 603-91737336
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Key words: Antigen detection, experimental invasive aspergillosis, sandwich ELISA

Abstract.
A biotin-avidin amplified sandwich ELISA utilizing polyclonal antibodies to water soluble (WS) mycelial antigens of Aspergillus fumigatus was used to detect antigens in sera of rabbits with experimental invasive aspergillosis. Tricolor rabbits were more susceptible to infection than NZW rabbits as evidenced by a faster progression of infection and greater isolation rates of A. fumigatus from organ culture. Antigenemia was detected in all 11 Tricolor rabbits inoculated with 1 x 10⁶ and 1 x 10⁷ conidia. However, antigenemia was detected in only 0%, 50% and 75% of NZW rabbits inoculated with 1 x 10⁶, 1 x 10⁷ and 1 x 10⁸ conidia, respectively. Tricolor rabbits demonstrated antigenemia in 75% (18 of 24) of sera, whilst only 36% (5 of 14) of sera of NZW rabbits tested positive. The overall sensitivity and specificity of antigen detection in Tricolor and NZW rabbits were 84.2% (16 of 19 rabbits) and 85.7% (12 of 14) respectively. The protein rich Concanavalin A unbound fraction of WS antigens demonstrated immunoreactivity with the BALISA. Immunoblot studies using the capture antibody demonstrated 3 strongly immunoreactive regions of 38-46kD, 66-68kD and 73-85kD for WS antigens. The results of partial characterization of WS antigens, suggests that the antigens detected are protein in nature.