MyMedR

Displaying all 4 publications

Abstract:

Sort:

Fulltext Comparative sensitivity to methyl eugenol of four putative Bactrocera dorsalis complex sibling species - further evidence that they belong to one and the same species B. dorsalis

Hee AK, Ooi YS, Wee SL, Tan KH

Zookeys, 2015.
PMID: 26798265 DOI: 10.3897/zookeys.540.6099

Males of certain species belonging to the Bactrocera dorsalis complex are strongly attracted to, and readily feed on methyl eugenol (ME), a plant secondary compound that is found in over 480 plant species worldwide. Amongst those species is one of the world's most severe fruit pests the Oriental fruit fly, Bactrocera dorsalis s.s., and the former taxonomic species Bactrocera invadens, Bactrocera papayae and Bactrocera philippinensis. The latter species have been recently synonymised with Bactrocera dorsalis based on their very similar morphology, mating compatibility, molecular genetics and identical sex pheromones following consumption of ME. Previous studies have shown that male fruit fly responsiveness to lures is a unique phenomenon that is dose species-specific, besides showing a close correlation to sexual maturity attainment. This led us to use ME sensitivity as a behavioural parameter to test if Bactrocera dorsalis and the three former taxonomic species had similar sensitivity towards odours of ME. Using Probit analysis, we estimated the median dose of ME required to elicit species' positive response in 50% of each population tested (ED50). ED50 values were compared between Bactrocera dorsalis and the former species. Our results showed no significant differences between Bactrocera dorsalis s.s., and the former Bactrocera invadens, Bactrocera papayae and Bactrocera philippinensis in their response to ME. We consider that the Bactrocera males' sensitivity to ME may be a useful behavioural parameter for species delimitation and, in addition to other integrative taxonomic tools used, provides further supportive evidence that the four taxa belong to one and the same biological species, Bactrocera dorsalis.
STR Data for the AmpFlSTR Identifiler loci in three ethnic groups (Malay, Chinese, Indian) of the Malaysian population

Seah LH, Jeevan NH, Othman MI, Jaya P, Ooi YS, Wong PC, et al.

Forensic Sci Int, 2003 Dec 17;138(1-3):134-7.
PMID: 14642733

Allele frequencies for the 15 STR loci in the AmpFlSTR Identifiler kit were determined and compared for the three main ethnic groups of the Malaysian population comprising 210 Malays, 219 Chinese and 209 Indians. Blood was placed on FTA paper and DNA was purified in-situ.
The Antibacterial Agent Identified from Acidocella spp. in the Fluid of Nepenthes gracilis Against Multidrug-Resistant Klebsiella pneumoniae: A Functional Metagenomic Approach

Chan EWL, Chin MY, Low YH, Tan HY, Ooi YS, Chong CW

Microb Drug Resist, 2021 Aug;27(8):1018-1028.
PMID: 33325795 DOI: 10.1089/mdr.2020.0311

Aims: The fluid of Nepenthes gracilis harbors diverse bacterial taxa that could serve as a gene pool for the discovery of the new genre of antimicrobial agents against multidrug-resistant Klebsiella pneumoniae. The aim of this study was to explore the presence of antibacterial genes in the fluids of N. gracilis growing in the wild. Methods: Using functional metagenomic approach, fosmid clones were isolated and screened for antibacterial activity against three strains of K. pneumoniae. A clone that exhibited the most potent antibacterial activity was sent for sequencing to identify the genes responsible for the observed activity. The secondary metabolites secreted by the selected clone was sequentially extracted using hexane, chloroform, and ethyl acetate. The chemical profiles of a clone (C6) hexane extract were determined by gas chromatography/mass spectrometry (GC-MS). Results: Fosmid clone C6 from the fluid of pitcher plant that exhibited antibacterial activity against three strains of K. pneumoniae was isolated using functional metagenome approach. A majority of the open reading frames detected from C6 were affiliated with the largely understudied Acidocella genus. Among them, the gene that encodes for coproporphyrinogen III oxidase in the heme biosynthesis pathway could be involved in the observed antibacterial activity. Based on the GC-MS analysis, the identities of the putative bioactive compounds were 2,5-di-tert-butylphenol and 1-ethyl-2-methyl cyclododecane. Conclusions: The gene that encodes for coproporphyrinogen III oxidase in the heme biosynthesis pathway as well as the secondary metabolites, namely 2,5-di-tert-butylphenol and 1-ethyl-2-methyl cyclododecane could be the potential antibacterial molecules responsible for the antibacterial activity of C6.
Fulltext Clinical characteristics and predictors of 5-year survival among colorectal cancer patients in a tertiary hospital in Malaysia

Lim KG, Lee CS, Chin DHJ, Ooi YS, Veettil SK, Ching SM, et al.

J Gastrointest Oncol, 2020 Apr;11(2):250-259.
PMID: 32399266 DOI: 10.21037/jgo.2020.02.04

Background: Colorectal cancer is the second most common cancer in Malaysia. Its disease burden is likely to increase over time owing to its current trends in this region. This study was undertaken to determine the 5-year survival rate and prognostic factors for survival in colorectal cancer patients treated in a tertiary hospital, in Malaysia.
Methods: We reviewed the records of colorectal cancer patients treated in Hospital Tuanku Ja'afar Seremban, Malaysia from 2008 to 2012. Survival analysis at five years was performed using the Kaplan-Meier method. Cox proportional hazard regression analysis was carried out to determine the predictors of 5-year colorectal cancer survival.
Results: Of the 275 patients, 43.3% were colon cancers, 51.8% were rectal cancers. Only 2.2% were diagnosed in Stage I. 28.7%, 33.1%, and 16.7% were in Stage II, III and IV respectively; 62/79 (78%) of Stage II patients were in Stage IIb; 15.7% of patients were below the age of 50 and fewer of them presented early (P=0.002). The overall 5-year survival was 46.5%. It was 67.9%, 50.5% and 12.8% for Stage I&II, III and IV patients respectively. Early stage of cancer (P<0.001) and age below the mean (P=0.01) were the most significant factor in predicting better survival. Gender and ethnic group were not associated with late presentation nor survival. Neither was there a difference between colon and rectum cancers nor patients who received elective surgical treatment compared to patients receiving other treatment first (P=0.085).
Conclusions: Late presentation is the most important predictor for poor outcome for colorectal cancer in Seremban. Patients under the age of 50 years present late more often, but do not have poorer survival.