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Production of clavulanic acid and cephamycin C by Streptomyces clavuligerus in palm-oil medium

Lee PC, Ho CC

World J Microbiol Biotechnol, 1996 Jan;12(1):73-5.
PMID: 24415093 DOI: 10.1007/BF00327805

Palm and palm-kernel oils and their olein and stearin fractions were suitable as the main carbon sources for growth and production of clavulanic acid by Streptomyces clavuligerus. However, oleic and lauric acids were not utilized for growth. A spontaneous mutant, which was selected for higher cephamycin C production, also produced more clavulanic acid with these oils in the medium.
Fulltext Development of insulated isothermal PCR for rapid on-site malaria detection

Chua KH, Lee PC, Chai HC

Malar J, 2016;15:134.
PMID: 26931146 DOI: 10.1186/s12936-016-1183-z

Detection of Plasmodium spp. is sometimes inconvenient especially in rural areas that are distant from a laboratory. In this study a portable diagnostic test of Plasmodium spp. was developed using insulated isothermal polymerase chain reaction (iiPCR) as an alternative approach to improve this situation.
Analysis of polymorphisms and selective pressures on ama1 gene in Plasmodium knowlesi isolates from Sabah, Malaysia

Chua CY, Lee PC, Lau TY

J Genet, 2017 Sep;96(4):653-663.
PMID: 28947714

The apical membrane antigen-1 (AMA-1) of Plasmodium spp. is a merozoite surface antigen that is essential for the recognition and invasion of erythrocytes. Polymorphisms occurring in this surface antigen will cause major obstacles in developing effective malaria vaccines based on AMA-1. The objective of this study was to characterize ama1 gene in Plasmodium knowlesi isolates from Sabah. DNA was extracted from blood samples collected from Keningau, Kota Kinabalu and Kudat. The Pkama1 gene was amplified using nested PCR and subjected to bidirectional sequencing. Analysis of DNA sequence revealed that most of the nucleotide polymorphisms were synonymous and concentrated in domain I of PkAMA-1. Forteen haplotypes were identified based on amino acid variations and haplotype K5 was the most common haplotype. dN/dS ratios implied that purifying selection was prevalent in Pkama1 gene. Fu and Li's D and F values further provided evidence of negative selection acting on domain II of Pkama1. Lownucleotide diversitywas also detected for the Pkama1 sequences,which is similar to reports on Pkama1 from Peninsular Malaysia and Sarawak. The presence of purifying selection and low nucleotide diversity indicated that domain II of Pkama1 can be used as a target for vaccine development.
Fulltext Draft genome sequence data of Streptomyces sp. FH025

Goh LPW, Mahmud F, Lee PC

Data Brief, 2021 Jun;36:107128.
PMID: 34095378 DOI: 10.1016/j.dib.2021.107128

The genome data of Streptomyces sp. FH025 comprised of 8,381,474 bp with a high GC content of 72.51%. The genome contains 7035 coding sequences spanning 1261 contigs. Streptomyces sp. FH025 contains 57 secondary metabolite gene clusters including polyketide synthase, nonribosomal polyketide synthase and other biosynthetic pathways such as amglyccycl, butyrolactone, terpenes, siderophores, lanthipeptide-class-iv, and ladderane. 16S rRNA analysis of Streptomyces sp. FH025 is similar to the Streptomyces genus. This whole genome project has been deposited at NCBI under the accession JAFLNG000000000.
Fulltext Investigation of a PAX6 gene mutation in a Malaysian family with congenital aniridia

Lee PC, Lam HH, Ghani SA, Subrayan V, Chua KH

Genet. Mol. Res., 2014;13(2):3553-9.
PMID: 24737507 DOI: 10.4238/2014.March.24.15

Mutations in the PAX6 gene that cause aniridia have been identified in various ethnicities but not in the Malaysian population. Therefore, the objective of this study was to investigate the PAX6 mutation in a Malaysian family with congenital aniridia. In this study, a complete ophthalmic examination was performed on a Dusun ethnic family with aniridia. Genomic DNA was extracted from the peripheral blood of the subjects and screened for the PAX6 gene mutation using polymerase chain reaction amplification high-resolution melting curve analysis (PCR-HRM) followed by confirmation via direct DNA sequencing. A heterozygous G deletion (c.857delG) in exon 7 causing a frame shift in PAX6 was identified in all affected family members. Genotype-phenotype correlation analysis revealed congenital cataract and all affected family members showed a similar spectrum of aniridia with no phenotypic variability but with differences in severity that were age-dependent. In summary, by using a PCR-HRM approach, this study is the first to report a PAX6 mutation in a Malaysian family. This mutation is the cause of the aniridia spectra observed in this family and of congenital cataract.
The value of potency testing of poliomyelitis and measles vaccines as an integral part of cold chain surveillance

Saraswathy TS, Sinniah M, Lee WS, Lee PC

Southeast Asian J. Trop. Med. Public Health, 1993 Jun;24(2):265-8.
PMID: 8266228

The Virology Division in the Institute for Medical Research, Kuala Lumpur, Malaysia performs potency tests on oral polio vaccines and live attenuated measles vaccines. Since these potency tests were introduced in 1981 a total of 752 tests have been performed on vaccine samples from peripheral immunization centers. Of 165 representative vaccine samples sent for potency evaluation after a cold chain breakdown 154 (87%) passed minimum potency requirements recommended for immunization of infants. In the absence of potency evaluation, those vaccines exposed to temperatures higher than the recommended storage range would be discarded, perhaps resulting in unnecessary wastage and economic loss. Results of the vaccine potency evaluation has enabled health authorities to indirectly monitor cold chain efficiency and ensure the high quality of viral vaccines used in our childhood immunization program.
Fulltext Prevalence of Alpha(α)-Thalassemia in Southeast Asia (2010-2020): A Meta-Analysis Involving 83,674 Subjects

Goh LPW, Chong ETJ, Lee PC

Int J Environ Res Public Health, 2020 10 09;17(20).
PMID: 33050119 DOI: 10.3390/ijerph17207354

Alpha(α)-thalassemia is a blood disorder caused by many types of inheritable α-globin gene mutations which causes no-to-severe clinical symptoms, such as Hb Bart's hydrops fetalis that leads to early foetal death. Therefore, the aim of this meta-analysis was to provide an update from year 2010 to 2020 on the prevalence of α-thalassemia in Southeast Asia. A systematic literature search was performed using PubMed and SCOPUS databases for related studies published from 2010 to 2020, based on specified inclusion and exclusion criteria. Heterogeneity of included studies was examined with the I2 index and Q-test. Funnel plots and Egger's tests were performed in order to determine publication bias in this meta-analysis. Twenty-nine studies with 83,674 subjects were included and pooled prevalence rates in this meta-analysis were calculated using random effect models based on high observed heterogeneity (I2 > 99.5, p-value < 0.1). Overall, the prevalence of α-thalassemia is 22.6%. The highest α-thalassemia prevalence was observed in Vietnam (51.5%) followed by Cambodia (39.5%), Laos (26.8%), Thailand (20.1%), and Malaysia (17.3%). No publication bias was detected. Conclusions: This meta-analysis suggested that a high prevalence of α-thalassemia occurred in selected Southeast Asia countries. This meta-analysis data are useful for designing thalassemia screening programs and improve the disease management.
Risk association, linkage disequilibrium and haplotype analyses of FASN rs4246445, rs2229425, rs2228305 and rs2229422 polymorphisms in overweight and obesity

Chong ETJ, Kuok SSE, Lee PC

Bioimpacts, 2018;8(3):159-165.
PMID: 30211075 DOI: 10.15171/bi.2018.18

Introduction:
Obesity is commonly linked up with several life-threatening diseases. This study aims to investigate the association of fatty acid synthase (FASN) rs4246445, rs2229425, rs2228305, and rs2229422 single nucleotide polymorphisms (SNPs) with the risk of overweight and obesity in the Malaysian population.
Methods:
Blood samples were collected from 1030 individuals who were grouped into normal, overweight, and obese categories. Blood biochemistry test and lipid profiling were performed and genomic DNA was extracted. Genotyping was performed using hydrolysis probes and odd ratio with 95% CI was calculated for risk association analysis. Linkage disequilibrium and haplotypes analyses were carried out using SHEsis software.
Results:
We found that the hemoglobin and white blood cell counts were significantly high in the obese subjects. There is a lack of evidence to link the FASN SNPs with the risk of overweight and obesity in the population. All 4 SNPs were seemed to be in linkage equilibrium. Five common haplotypes were identified in this study but none of them was significantly associated with overweight and obesity in the population.
Conclusion:
Our findings suggest a lack of evidence to associate the FASN rs4246445, rs2229425, rs2228305, and rs2229422 SNPs with the risk of overweight and obesity in the Malaysian population. All 4 SNPs were independent of each other and not all identified haplotypes were significantly associated with overweight and obesity in this study.
Population data of six Alu insertions in indigenous groups from Sabah, Malaysia

Kee BP, Chua KH, Lee PC, Lian LH

Ann Hum Biol, 2012 Nov-Dec;39(6):505-10.
PMID: 22989108 DOI: 10.3109/03014460.2012.719548

The present study is the first to report the genetic relatedness of indigenous populations of Sabah, Malaysia, using a set of Indel markers (HS4.32, TPA25, APO, PV92, B65 and HS3.23). The primary aim was to assess the genetic relationships among these populations and with populations from other parts of the world by examining the distribution of these markers.
Fulltext Bacterial polysaccharides-A big source for prebiotics and therapeutics

Khan R, Shah MD, Shah L, Lee PC, Khan I

Front Nutr, 2022;9:1031935.
PMID: 36407542 DOI: 10.3389/fnut.2022.1031935

Bacterial polysaccharides are unique due to their higher purity, hydrophilic nature, and a finer three-dimensional fibrous structure. Primarily, these polymers provide protection, support, and energy to the microorganism, however, more recently several auxiliary properties of these biopolymers have been unmasked. Microbial polysaccharides have shown therapeutic abilities against various illnesses, augmented the healing abilities of the herbal and Western medicines, improved overall health of the host, and have exerted positive impact on the growth of gut dwelling beneficial bacteria. Specifically, the review is discussing the mechanism through which bacterial polysaccharides exert anti-inflammatory, antioxidant, anti-cancer, and anti-microbial properties. In addition, they are holding promising application in the 3D printing. The review is also discussing a perspective about the metagenome-based screening of polysaccharides, their integration with other cutting-edge tools, and synthetic microbiome base intervention of polysaccharides as a strategy for prebiotic intervention. This review has collected interesting information about the bacterial polysaccharides from Google Scholar, PubMed, Scopus, and Web of Science databases. Up to our knowledge, this is the first of its kind review article that is summarizing therapeutic, prebiotics, and commercial application of bacterial polysaccharides.
An Updated Review on the Role of Single Nucleotide Polymorphisms in COVID-19 Disease Severity: A Global Aspect

Ng JW, Chong ETJ, Lee PC

Curr Pharm Biotechnol, 2022 Jan 14.
PMID: 35034591 DOI: 10.2174/1389201023666220114162347

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and recently has become a serious global pandemic. Age, gender, and comorbidities are known to be common risk factors for severe COVID-19 but are not enough to fully explain the magnitude of their effect on the risk of severity of the disease. Single nucleotide polymorphisms (SNPs) in several genes have been reported as a genetic factor contributing to COVID-19 severity. This comprehensive review focuses on the association between SNPs in four important genes and COVID-19 severity in a global aspect. We discuss a total of 39 SNPs in this review: five SNPs in the ABO gene, nine SNPs in the angiotensin-converting enzyme 2 (ACE2) gene, 19 SNPs in the transmembrane protease serine 2 (TMPRSS2) gene, and six SNPs in the toll-like receptor 7 (TLR7) gene. These SNPs data could assist in monitoring an individual's risk of severe COVID-19 disease, and therefore personalized management and pharmaceutical treatment could be planned in COVID-19 patients.
Fulltext Association between EGF and VEGF functional polymorphisms and sporadic colorectal cancer in the Malaysian population

Lau TP, Roslani AC, Lian LH, Lee PC, Hilmi I, Goh KL, et al.

Genet. Mol. Res., 2014;13(3):5555-61.
PMID: 25117311 DOI: 10.4238/2014.July.25.9

Growth factors are polypeptides that are critical for the initiation, progression, and metastasis of cancer. Most tumor cells are capable of synthesizing particular growth factors leading to constitutive pathway activation in these cells through autocrine signaling. Epidermal growth factor (EGF) is a potent mitogenic peptide that exerts direct effects on the proliferation and differentiation of tumor cells in carcinogenesis. By contrast, vascular endothelial growth factor (VEGF) is vital for the invasion and metastasis of neoplasms through the formation of new blood vessels from mature endothelial cells. In this study, we investigated the association between functional polymorphisms of both the EGF and VEGF genes and colorectal cancer (CRC) susceptibility. A total of 130 CRC patients and 212 healthy controls were recruited for this case-control study. Genotyping of genetic variants was conducted via real-time polymerase chain reaction (PCR) amplification with allele-specific TaqMan probes. None of the genotypes of the EGF +61 A>G and VEGF +936 C>T variants was significantly associated with CRC susceptibility among the Malaysian subjects evaluated (P > 0.05). The observed frequency distributions of the EGF +61 A>G polymorphism genotypes showed ethnic heterogeneity, which was not the case for the VEGF +936 C>T genotypes. In conclusion, no positive correlation between these functional polymorphisms and CRC risk was found in this Malaysian population. Studies of the EGF and VEGF genes and CRC susceptibility are scarce, and the results reported thus far differ from one population to another. Hence, more replication studies are warranted before any firm conclusions can be made.
Significant genotype difference in the CYP2E1 PstI polymorphism of indigenous groups in Sabah, Malaysia with Asian and non-Asian populations

Goh LP, Chong ET, Chua KH, Chuah JA, Lee PC

Asian Pac J Cancer Prev, 2014;15(17):7377-81.
PMID: 25227845

CYP2E1 PstI polymorphism G-1259C (rs3813867) genotype distributions vary significantly among different populations and are associated with both diseases, like cancer, and adverse drug effects. To date, there have been limited genotype distributions and allele frequencies of this polymorphism reported in the three major indigenous ethnic groups (KadazanDusun, Bajau, and Rungus) in Sabah, also known as North Borneo. The aim of this study was to investigate the genotype distributions and allele frequencies of the CYP2E1 PstI polymorphism G-1259C in these three major indigenous peoples in Sabah. A total of 640 healthy individuals from the three dominant indigenous groups were recruited for this study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) at G-1259C polymorphic site of CYP2E1 gene was performed using the Pst I restriction enzyme. Fragments were analyzed using agarose gel electrophoresis and confirmed by direct sequencing. Overall, the allele frequencies were 90.3% for c1 allele and 9.7% for c2 allele. The genotype frequencies for c1/c1, c1/c2 and c2/c2 were observed as 80.9%, 18.8%, and 0.3%, respectively. A highly statistical significant difference (p<0.001) was observed in the genotype distributions between indigenous groups in Sabah with all Asian and non-Asian populations. However, among these three indigenous groups, there was no statistical significant difference (p>0.001) in their genotype distributions. The three major indigenous ethnic groups in Sabah show unique genotype distributions when compared with other populations. This finding indicates the importance of establishing the genotype distributions of CYP2E1 PstI polymorphism in the indigenous populations.
Fulltext NOD2/CARD15 variants in Malaysian patients with sporadic colorectal cancer

Lau TP, Roslani AC, Lian LH, Lee PC, Hilmi I, Goh KL, et al.

Genet. Mol. Res., 2014;13(3):7079-85.
PMID: 24682985 DOI: 10.4238/2014.March.19.3

Colorectal cancer (CRC) is one of the most common types of cancer in both developed and developing countries. This disease is triggered by and progresses via the sequential accumulation of multiple genetic alterations. In addition, the interaction between low-penetrance genes and environmental factors can also increase the risk of developing CRC. Since inflammatory bowel diseases (IBDs) are one of the predisposing factors for CRC, IBD-related genes might, to a certain extent, be associated with cancer initiation. The nucleotide oligomerization domain 2/caspase activating recruitment domain 15 gene (NOD2/CARD15) is the most well-established gene to be associated with increased susceptibility to Crohn's disease. Thus, various studies have been performed to investigate the potential contribution of this gene to CRC risk. In this study, we aimed to determine the frequency of the Arg702Trp, Gly908Arg, 3020insC, Pro268Ser, and JW1 variants of NOD2/CARD15, and to investigate their association with CRC susceptibility. A total of 130 CRC patients and 212 healthy controls were recruited for this study. Subsequently, real-time polymerase chain reaction with TaqMan was performed for the genotyping of these NOD2/ CARD15 variants. None of the NOD2/CARD15 variants was statistically associated to CRC susceptibility in our Malaysian population. Our findings were remarkably similar to those of other Asian cohorts, which indicated that these NOD2/CARD15 variants exhibit genetic heterogeneity between Caucasian and Asian populations.
Fulltext RsaI but not DraI polymorphism in CYP2E1 gene increases the risk of gastrointestinal cancer in Malaysians: a case-control study

Chong ET, Lee CC, Chua KH, Chuah JA, Lee PC

BMJ Open, 2014;4(1):e004109.
PMID: 24394801 DOI: 10.1136/bmjopen-2013-004109

Our study aimed to investigate the association of CYP2E1 C-1019T RsaI and T7678A DraI polymorphisms and factors such as age, gender and ethnicity to the risk of gastrointestinal cancer (GIC) in Malaysians.
Fulltext Genetic data for 15 STR loci in a Kadazan-Dusun population from East Malaysia

Kee BP, Lian LH, Lee PC, Lai TX, Chua KH

Genet. Mol. Res., 2011;10(2):739-43.
PMID: 21523653 DOI: 10.4238/vol10-2gmr1064

Allele frequencies of 15 short tandem repeat (STR) loci, namely D5S818, D7S820, D13S317, D16S539, TH01, TPOX, Penta D, Penta E, D3S1358, D8S1179, D18S51, D21S11, CSF1PO, vWA, and FGA, were determined for 154 individuals from the Kadazan-Dusun tribe, an indigenous population of East Malaysia. All loci were amplified by polymerase chain reaction, using the Powerplex 16 system. Alleles were typed using a gene analyzer and the Genemapper ID software. Various statistical parameters were calculated and the combined power of discrimination for the 15 loci in the population was calculated as 0.999999999999999. These loci are thus, informative and can be used effectively in forensic and genetic studies of this indigenous population.
Fulltext Development of High Resolution Melting Analysis for the Diagnosis of Human Malaria

Chua KH, Lim SC, Ng CC, Lee PC, Lim YA, Lau TP, et al.

Sci Rep, 2015;5:15671.
PMID: 26507008 DOI: 10.1038/srep15671

Molecular detection has overcome limitations of microscopic examination by providing greater sensitivity and specificity in Plasmodium species detection. The objective of the present study was to develop a quantitative real-time polymerase chain reaction coupled with high-resolution melting (qRT-PCR-HRM) assay for rapid, accurate and simultaneous detection of all five human Plasmodium spp. A pair of primers targeted the 18S SSU rRNA gene of the Plasmodium spp. was designed for qRT-PCR-HRM assay development. Analytical sensitivity and specificity of the assay were evaluated. Samples collected from 229 malaria suspected patients recruited from Sabah, Malaysia were screened using the assay and results were compared with data obtained using PlasmoNex(TM), a hexaplex PCR system. The qRT-PCR-HRM assay was able to detect and discriminate the five Plasmodium spp. with lowest detection limits of 1-100 copy numbers without nonspecific amplifications. The detection of Plasmodium spp. in clinical samples using this assay also achieved 100% concordance with that obtained using PlasmoNex(TM). This indicated that the diagnostic sensitivity and specificity of this assay in Plasmodium spp. detection is comparable with those of PlasmoNex(TM). The qRT-PCR-HRM assay is simple, produces results in two hours and enables high-throughput screening. Thus, it is an alternative method for rapid and accurate malaria diagnosis.
Association of CYP2E1, STK15 and XRCC1 Polymorphisms with Risk of Breast Cancer in Malaysian Women

Chong ET, Goh LP, See EU, Chuah JA, Chua KH, Lee PC

Asian Pac J Cancer Prev, 2016;17(2):647-53.
PMID: 26925658

BACKGROUND: Breast cancer is the most common type of cancer affecting Malaysian women. Recent statistics revealed that the cumulative probability of breast cancer and related deaths in Malaysia is higher than in most of the countries of Southeast Asia. Single nucleotide polymorphisms (SNPs) in CYP2E1 (rs6413432 and rs3813867), STK15 (rs2273535 and rs1047972) and XRCC1 (rs1799782 and rs25487) have been associated with breast cancer risk in a meta-analysis but any link in Southeast Asia, including Malaysia, remained to be determined. Hence, we investigated the relationship between these SNPs and breast cancer risk among Malaysian women in the present case-control study.
MATERIALS AND METHODS: Genomic DNA was isolated from peripheral blood of 71 breast cancer patients and 260 healthy controls and subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.
RESULTS: Our study showed that the c1/c2 genotype or subjects with at least one c2 allele in CYP2E1 rs3813867 SNP had significantly increased almost 1.8-fold higher breast cancer risk in Malaysian women overall. In addition, the variant Phe allele in STK15 rs2273535 SNP appeared to protect against breast cancer in Malaysian Chinese. No significance association was found between XRCC1 SNPs and breast cancer risk in the population.
CONCLUSIONS: This study provides additional knowledge on CYP2E1, STK15 and XRCC1 SNP impact of risk of breast cancer, particularly in the Malaysian population. From our findings, we also recommend Malaysian women to perform breast cancer screening before 50 years of age.
Fulltext Draft Genome Sequence of Flavobacterium sp. Strain PL002, Isolated from Antarctic Porphyra Algae

Teoh CP, Lavin P, Najimudin N, Lee PC, Iancu L, Purcarea C, et al.

Microbiol Resour Announc, 2021 Feb 25;10(8).
PMID: 33632855 DOI: 10.1128/MRA.00063-21

Here, we report the draft genome sequence of Flavobacterium sp. strain PL002, isolated from Antarctic Porphyra algae. The 4,299,965-bp genome sequence is assembled into 170 contigs, has 32.92% GC content, and 3,734 predicted genes.
Fulltext Anti-malarial and anti-inflammatory effects of Gleichenia truncata mediated through inhibition of GSK3β

Suhaini S, Liew SZ, Norhaniza J, Lee PC, Jualang G, Embi N, et al.

Trop Biomed, 2015 Sep;32(3):419-33.
PMID: 26695202 MyJurnal

Gleichenia truncata is a highland fern from the Gleicheniaceae family known for its traditional use among indigenous communities in Asia to treat fever. The scientific basis of its effect has yet to be documented. A yeast-based kinase assay conducted in our laboratory revealed that crude methanolic extract (CME) of G. truncata exhibited glycogen synthase kinase-3 (GSK3)-inhibitory activity. GSK3β is now recognized to have a pivotal role in the regulation of inflammatory response during bacterial infections. We have also previously shown that lithium chloride (LiCl), a GSK3 inhibitor suppressed development of Plasmodium berghei in a murine model of malarial infection. The present study is aimed at evaluating G. truncata for its anti-malarial and anti-inflammatory effects using in vivo malarial and melioidosis infection models respectively. In a four-day suppressive test, intraperitoneal injections of up to 250 mg/kg body weight (bw) G. truncata CME into P.berghei-infected mice suppressed parasitaemia development by >60%. Intraperitoneal administration of 150 mg/kg bw G. truncata CME into Burkholderia pseudomallei-infected mice improved survivability by 44%. G. truncata CME lowered levels of pro-inflammatory cytokines (TNF-α, IFN-γ) in serum and organs of B. pseudomallei-infected mice. In both infections, increased phosphorylations (Ser9) of GSK3β were detected in organ samples of animals administered with G. truncata CME compared to controls. Taken together, results from this study strongly suggest that the anti-malarial and anti-inflammatory effects elicited by G. truncata in part were mediated through inhibition of GSK3β. The findings provide scientific basis for the ethnomedicinal use of this fern to treat inflammation-associated symptoms.

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