MyMedR

Characterization of Coconut cadang-cadang viroid variants from oil palm affected by orange spotting disease in Malaysia

Wu YH, Cheong LC, Meon S, Lau WH, Kong LL, Joseph H, et al.

Arch Virol, 2013 Jun;158(6):1407-10.

PMID: 23397332 DOI: 10.1007/s00705-013-1624-8

A 246-nt variant of Coconut cadang-cadang viroid (CCCVd) has been identified and described from oil palms with orange spotting symptoms in Malaysia. Compared with the 246-nt form of CCCVd from coconut, the oil palm variant substituted C(31)→U in the pathogenicity domain and G(70)→C in the central conserved domain. This is the first sequence reported for a 246-nt variant of CCCVd in oil palms expressing orange spotting symptoms.

Matched MeSH terms: Point Mutation/genetics

Fulltext Full-length sequence analysis of chloroquine resistance transporter gene in Plasmodium falciparum isolates from Sabah, Malaysia

Tan LL, Lau TY, Timothy W, Prabakaran D

ScientificWorldJournal, 2014;2014:935846.

PMID: 25574497 DOI: 10.1155/2014/935846

Chloroquine resistance (CQR) in falciparum malaria was identified to be associated with several mutations in the chloroquine resistance transporter gene (pfcrt) that encodes the transmembrane transporter in digestive vacuole membrane of the parasite. This study aimed to investigate the point mutations across the full-length pfcrt in Plasmodium falciparum isolates in Sabah, Malaysia. A total of 31 P. falciparum positive samples collected from Keningau, Kota Kinabalu, and Kudat, Sabah, were analyzed. pfcrt was PCR amplified and cloned prior to sequence analysis. This study showed that all the previously described 10 point mutations associated with CQR at codons 72, 74, 75, 76, 97, 220, 271, 326, 356, and 371 were found with different prevalence. Besides, two novel point mutations, I166V and H273N, were identified with 22.5% and 19.3%, respectively. Three haplotypes, namely, CVMNK (29%), CVIET (3.2%), and SVMNT (67.7%), were identified. High prevalence of SVMNT among P. falciparum isolates from Sabah showed that these isolates are closer to the P. falciparum isolates from Papua New Guinea rather than to the more proximal Southeast Asian CVIET haplotype. Full-length analysis of pfcrt showed that chloroquine resistant P. falciparum in Sabah is still prevalent despite the withdrawal of chloroquine usage since 1979.

Matched MeSH terms: Point Mutation/genetics

Screening for gap junction protein beta-2 gene mutations in Malays with autosomal recessive, non-syndromic hearing loss, using denaturing high performance liquid chromatography

Aishah ZS, Khairi MD, Normastura AR, Zafarina Z, Zilfalil BA

J Laryngol Otol, 2008 Dec;122(12):1284-8.

PMID: 18353197 DOI: 10.1017/S0022215108002041

To determine the frequency and type of gap junction protein beta-2 gene mutations in Malay patients with autosomal recessive, non-syndromic hearing loss.

Matched MeSH terms: Point Mutation/genetics*

Genetic diversity of chicken anemia virus following cell culture passaging in MSB-1 cells

Hasmah MS, Omar AR, Wan KF, Hair-Bejo M, Aini I

Acta Virol., 2004;48(2):85-9.

PMID: 15462283

It has been shown that a chicken anemia virus (CAV) isolates which had undergone 60 passages in MSB-1 cells (SMSC-1/P60, 3-1/P60) acquired 33-66 nucleotide substitutions at the coding region resulting in 13-16 amino acid changes as compared to the CAV isolates passaged only 5 times in MSB-1 cells (SMSC-1 and 3-1) (Chowdhury et al., Arch. Virol. 148, 2437-2448, 2003). In this study we found that a low CAV (BL-5) and a high CAV passage (BL-5/P90) differed by only 15 nucleotide substitutions resulting in 11 amino acid changes. Phylogenetic analysis based on VP1 also revealed that both isolates were close to each other but not to other CAV isolates from Malaysia, namely SMSC-1 and 3-1.

Matched MeSH terms: Point Mutation/genetics

Fulltext Detection of carrier status of hemophilia B using DNA markers

Ishak R, Zakaria Z

Southeast Asian J. Trop. Med. Public Health, 1997 Sep;28(3):629-30.

PMID: 9561621

Hemophilia B is an X-linked recessive disorder of the hemostasis involving a defective clotting factor IX. Amplification of the regions containing restriction fragment length polymorphisms (RFLP) can be achieved by the use of polymerase chain reaction (PCR). This paper describes the analysis of 2 RFLPs involving the Dde1 and Taq1 restriction sites within the factor IX gene in a family with hemophilia B. Digestion of the PCR products with Taq1 revealed a 163bp fragment in all the family members. This finding suggests the absence of restriction site for Taq1 enzyme. However, the Dde1 digest results in bands 369bp and 319bp segregated amongst the family members. The pattern of inheritance of the 369bp fragment in this family suggested that both the patient's mother and aunt are not carriers and that the patient's factor IX gene could have undergone a de novo mutation producing a defective factor IX gene responsible for the hemophilia B. This is supported by the fact that no family history of hemophilia B is indicated in the other male members within the family.

Matched MeSH terms: Point Mutation/genetics

RNA-binding region of Macrobrachium rosenbergii nodavirus capsid protein

Goh ZH, Mohd NAS, Tan SG, Bhassu S, Tan WS

J Gen Virol, 2014 Sep;95(Pt 9):1919-1928.

PMID: 24878641 DOI: 10.1099/vir.0.064014-0

White tail disease (WTD) kills prawn larvae and causes drastic losses to the freshwater prawn (Macrobrachium rosenbergii) industry. The main causative agent of WTD is Macrobrachium rosenbergii nodavirus (MrNV). The N-terminal end of the MrNV capsid protein is very rich in positively charged amino acids and is postulated to interact with RNA molecules. N-terminal and internal deletion mutagenesis revealed that the RNA-binding region is located at positions 20-29, where 80 % of amino acids are positively charged. Substitution of all these positively charged residues with alanine abolished the RNA binding. Mutants without the RNA-binding region still assembled into virus-like particles, suggesting that this region is not a part of the capsid assembly domain. This paper is, to the best of our knowledge, the first to report the specific RNA-binding region of MrNV capsid protein.

Matched MeSH terms: Point Mutation/genetics

X-linked Charcot-Marie-Tooth disease predominates in a cohort of multiethnic Malaysian patients

Shahrizaila N, Samulong S, Tey S, Suan LC, Meng LK, Goh KJ, et al.

Muscle Nerve, 2014 Feb;49(2):198-201.

PMID: 23649551 DOI: 10.1002/mus.23892

Data regarding Charcot-Marie-Tooth disease is lacking in Southeast Asian populations. We investigated the frequency of the common genetic mutations in a multiethnic Malaysian cohort.

Matched MeSH terms: Point Mutation/genetics

Clarithromycin resistance and point mutations in the 23S rRNA gene in Helicobacter pylori isolates from Malaysia

Ho SL, Tan EL, Sam CK, Goh KL

J Dig Dis, 2010 Apr;11(2):101-5.

PMID: 20402836 DOI: 10.1111/j.1751-2980.2010.00423.x

To determine the prevalence of primary clarithromycin resistance amongst Helicobacter pylori (H. pylori) strains in Malaysian patients with gastroduodenal diseases, by using restriction fragment length polymorphism (RFLP) in domain V of 23S rRNA.

Matched MeSH terms: Point Mutation/genetics*

Activated protein C resistance: a study among 60 thromboembolic patients in the Singapore population

Lim LC, Tan HH, Lee LH, Tien SL, Abdul Ghafar A

Ann Acad Med Singap, 1999 Mar;28(2):252-5.

PMID: 10497677

Resistance to activated protein C (APC-R) is the commonest inherited cause of thrombosis among Caucasians. Few studies have been carried out on its prevalence in Asians. We conducted a prospective study on 60 patients with thromboembolism to determine its prevalence in our local population. The Factor V Leiden (VaQ506) mutation associated with this condition was detected by amplification of the Factor V gene by polymerase chain reaction (PCR) and digestion of the fragment with Mnl I. Three patients were found to be heterozygous for this mutation. None of the 3 patients had other concomitant hypercoagulable states. In addition, we studied the prevalence of this condition in Malays which was found to be 0.5%. Our study suggests that the incidence of APC-R is much lower here compared to the West.

Matched MeSH terms: Point Mutation/genetics

Interaction of Hb South Florida (codon 1; GTG-->ATG) and HbE, with beta-thalassemia (IVS1-1; G-->A): expression of different clinical phenotypes

Tan JA, Tan KL, Omar KZ, Chan LL, Wee YC, George E

Eur J Pediatr, 2009 Sep;168(9):1049-54.

PMID: 19034506 DOI: 10.1007/s00431-008-0877-9

INTRODUCTION: Interactions of different hemoglobin variants with thalassemia alleles can result in various clinical phenotypes. HbE-beta-thalassemia generally manifests with severe anemia where individuals exhibit beta-thalassemia major with regular blood transfusions or beta-thalassemia intermedia with periodic blood transfusions. This study presents a unique Malay family with three beta-globin gene defects-HbE, Hb South Florida, and IVS1-1 (G-->A).

MATERIALS AND METHODS: HbE activates a cryptic splice site that produces non-functional mRNAs. Hb South Florida is a rare beta-hemoglobin variant, and its interactions with other beta-thalassemia alleles have not been reported. IVS1-1 is a Mediterranean mutation that affects mRNA processing giving rise to beta(o)-thalassemia.

RESULTS AND DISCUSSION: Fifteen mutations along the beta-globin gene complex were analyzed using the amplification refractory mutation system. Hb South Florida was identified by direct sequencing using genomic DNA.

CONCLUSION: The affected child with HbE/IVS1-1 produced a beta-thalassemia major phenotype. Compound heterozygosity for Hb South Florida/IVS1-1 produced a beta-thalassemia carrier phenotype in the mother.

Matched MeSH terms: Point Mutation/genetics*

Association of p53 tumor suppressor gene with paraclinical and clinical modalities of gliomas patients in Malaysia

Yusoff AA, Abdullah J, Abdullah MR, Mohd Ariff AR, Isa MN

Acta Neurochir (Wien), 2004 Jun;146(6):595-601.

PMID: 15168228

Alteration of the tumor suppressor gene p53 is considered to be a critical step in the development of human cancer. Changes in this gene have been detected in a wide range of human tumours, including gliomas. In glioma, the presence of p53 gene alterations has been associated with worse prognosis.

Matched MeSH terms: Point Mutation/genetics

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