Displaying publications 1 - 20 of 78 in total

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  1. Liang JS, Hung KL, Lin LJ, Ong WP, Keng WT, Lu JF
    Epilepsy Behav, 2023 Aug;145:109266.
    PMID: 37385119 DOI: 10.1016/j.yebeh.2023.109266
    Zellweger spectrum disorders (ZSD) are rare autosomal recessive disorders caused by defects in peroxisome biogenesis factor (PEX; peroxin) genes leading to impaired transport of peroxisomal proteins with peroxisomal targeting signals (PTS). Four patients, including a pair of homozygotic twins, diagnosed as ZSD by genetic study with different clinical presentations and outcomes as well as various novel mutations are described here. A total of 3 novel mutations, including a nonsense, a frameshift, and a splicing mutation, in PEX1 from ZSD patients were identified and unequivocally confirmed that the p.Ile989Thr mutant PEX1 exhibited temperature-sensitive characteristics and is associated with milder ZSD. The nature of the p.Ile989Thr mutant exhibited different characteristics from that of the other previously identified temperature-sensitive p.Gly843Asp PEX1 mutant. Transcriptome profiles under nonpermissive vs. permissive conditions were explored to facilitate the understanding of p.Ile989Thr mutant PEX1. Further investigation of molecular mechanisms may help to clarify potential genetic causes that could modify the clinical presentation of ZSD.
    Matched MeSH terms: Membrane Proteins/genetics
  2. Ng YL, Fong MY, Lau YL
    Trop Biomed, 2021 Jun 01;38(2):159-164.
    PMID: 34172705 DOI: 10.47665/tb.38.2.052
    The Plasmodium knowlesi apical membrane antigen-1 (PkAMA-1) plays an important role in the invasion of the parasite into its host erythrocyte, and it has been regarded as a potential vaccine candidate against human knowlesi malaria. This study investigates genetic diversity and natural selection of the full length PkAMA-1 of P. knowlesi clinical isolates from Peninsular Malaysia. Blood samples were collected from P. knowlesi malaria patients from Peninsular Malaysia. The PkAMA-1 gene was amplified from DNA samples using PCR, cloned into a plasmid vector and sequenced. Results showed that nucleotide diversity of the full length PkAMA-1 from Peninsular Malaysia isolates (π: 0.006) was almost similar to that of Sarawak (π: 0.005) and Sabah (π: 0.004) isolates reported in other studies. Deeper analysis revealed Domain I (π: 0.007) in the PkAMA-1 had the highest diversity as compared to Domain II (π: 0.004) and Domain III (π: 0.003). Z-test indicated negative (purifying) selection of the gene. Combined alignment analysis at the amino acid level for the Peninsular Malaysia and Sarawak PkAMA-1 sequences revealed 34 polymorphic sites. Thirty-one of these sites were dimorphic, and 3 were trimorphic. The amino acid sequences could be categorised into 31 haplotypes. In the haplotype network, PkAMA-1 from Peninsular Malaysia and Sarawak were separated into two groups.
    Matched MeSH terms: Membrane Proteins/genetics*
  3. Alessandro L, Low KE, Abushelaibi A, Lim SE, Cheng WH, Chang SK, et al.
    Int J Mol Sci, 2022 Nov 18;23(22).
    PMID: 36430761 DOI: 10.3390/ijms232214285
    The diagnosis of endometrial cancer involves sequential, invasive tests to assess the thickness of the endometrium by a transvaginal ultrasound scan. In 6−33% of cases, endometrial biopsy results in inadequate tissue for a conclusive pathological diagnosis and 6% of postmenopausal women with non-diagnostic specimens are later discovered to have severe endometrial lesions. Thus, identifying diagnostic biomarkers could offer a non-invasive diagnosis for community or home-based triage of symptomatic or asymptomatic women. Herein, this study identified high-risk pathogenic nsSNPs in the NRAS gene. The nsSNPs of NRAS were retrieved from the NCBI database. PROVEAN, SIFT, PolyPhen-2, SNPs&GO, PhD-SNP and PANTHER were used to predict the pathogenicity of the nsSNPs. Eleven nsSNPs were identified as “damaging”, and further stability analysis using I-Mutant 2.0 and MutPred 2 indicated eight nsSNPs to cause decreased stability (DDG scores < −0.5). Post-translational modification and protein−protein interactions (PPI) analysis showed putative phosphorylation sites. The PPI network indicated a GFR-MAPK signalling pathway with higher node degrees that were further evaluated for drug targets. The P34L, G12C and Y64D showed significantly lower binding affinity towards GTP than wild-type. Furthermore, the Kaplan−Meier bioinformatics analyses indicated that the NRAS gene deregulation affected the overall survival rate of patients with endometrial cancer, leading to prognostic significance. Findings from this could be considered novel diagnostic and therapeutic markers.
    Matched MeSH terms: Membrane Proteins/genetics
  4. Garg A, Keng WT, Chen Z, Sathe AA, Xing C, Kailasam PD, et al.
    J Clin Invest, 2022 Dec 01;132(23).
    PMID: 36282599 DOI: 10.1172/JCI156864
    Multiple genetic loci have been reported for progeroid syndromes. However, the molecular defects in some extremely rare forms of progeria have yet to be elucidated. Here, we report a 21-year-old man of Chinese ancestry who has an autosomal recessive form of progeria, characterized by severe dwarfism, mandibular hypoplasia, hyperopia, and partial lipodystrophy. Analyses of exome sequencing data from the entire family revealed only 1 rare homozygous missense variant (c.86C>T; p.Pro29Leu) in TOMM7 in the proband, while the parents and 2 unaffected siblings were heterozygous for the variant. TOMM7, a nuclear gene, encodes a translocase in the outer mitochondrial membrane. The TOMM complex makes up the outer membrane pore, which is responsible for importing many preproteins into the mitochondria. A proteomic comparison of mitochondria from control and proband-derived cultured fibroblasts revealed an increase in abundance of several proteins involved in oxidative phosphorylation, as well as a reduction in abundance of proteins involved in phospholipid metabolism. We also observed elevated basal and maximal oxygen consumption rates in the fibroblasts from the proband as compared with control fibroblasts. We concluded that altered mitochondrial protein import due to biallelic loss-of-function TOMM7 can cause severe growth retardation and progeroid features.
    Matched MeSH terms: Membrane Proteins/genetics
  5. Eshaghi M, Ali AM, Jamal F, Yusoff K
    J. Biochem. Mol. Biol. Biophys., 2002 Feb;6(1):23-8.
    PMID: 12186779
    Streptococcus pyogenes ST4547 is an opacity factor negative strain, which has been recently reported as a new emm type from Malaysia. Nucleotide sequencing of the mga regulon of this strain showed the existence of two emm-like genes. The emm gene located upstream of the scpA gene comprises 1305 nucleotides encoding the putative precursor M protein of 435 amino acids in length with an M(r) of 49 kDa. or a predicted mature protein of 394 amino acids with an M(r) of 44.8 kDa. Another gene mrpST4547 was located upstream of the emm gene and downstream of the mga gene. The sequence of this mrp gene comprises 1167 nucleotides encoding a predicted protein of 388 amino acids in length with an M(r) of 42.2 kDa. or a predicted mature protein of 347 amino acids with an M(r) of 37.9 kDa. The mga regulon of strain ST4547 has a mosaic structure comprising segments, which originated from different OF positive and OF negative strains. The sequences flanking the hyper-variable and C repeats of the emmST4547 gene showed high similarity to corresponding regions in the mga regulon of OF positive strains notably M15, M4, M22 and M50. In contrast, the sequence within the hyper-variable and C repeat regions of the emmST4547 gene revealed high similarity to equivalent regions in the OF negative strains. These data indicates that horizontal transfer of emm-like gene could have occurred between OF positive and OF negative strains resulting in architectural divergence in the mga regulon.
    Matched MeSH terms: Bacterial Outer Membrane Proteins/genetics*; Membrane Proteins/genetics*
  6. Chang PY, Fong MY, Nissapatorn V, Lau YL
    Am J Trop Med Hyg, 2011 Sep;85(3):485-9.
    PMID: 21896809 DOI: 10.4269/ajtmh.2011.11-0351
    Rhoptry protein 2 (ROP2) of Toxoplasma gondii is a rhoptry-secreted protein that plays a critical role in parasitophorous vacuole membrane formation during invasion. In previous studies, ROP2 has been shown to be efficient in triggering humoral and cell-mediated responses. High immunogenicity of ROP2 makes it a potential candidate for diagnosis and vaccination against toxoplasmosis. In this study, the ROP2 gene was cloned into pPICZα A expression vector and extracellularly expressed in the yeast Pichia pastoris, which has numerous advantages over other expression systems for eukaryotic proteins expression. The effectiveness of the secreted recombinant ROP2 as a diagnosis agent was assessed by Western Blot with 200 human serum samples. Recombinant ROP2 reacted with toxoplasmosis-positive human serum samples and yielded an overall sensitivity of 90% and specificity of 95%. However, recombinant ROP2 is a better marker for detection of IgG (91.7%) rather than IgM (80%).
    Matched MeSH terms: Membrane Proteins/genetics
  7. Fong MY, Wong SS, Silva JR, Lau YL
    Acta Trop, 2015 Dec;152:145-150.
    PMID: 26384455 DOI: 10.1016/j.actatropica.2015.09.009
    The simian malaria parasite Plasmodium knowlesi is now recognized as a species that can cause human malaria. The first report of large scale human knowlesi malaria was in 2004 in Malaysia Borneo. Since then, hundreds of human knowlesi malaria cases have been reported in Southeast Asia. The present study investigates the genetic polymorphism of P. knowlesi DI domain of the apical membrane antigen-1 (AMA-1), a protein considered as a promising vaccine candidate for malaria. The DI domain of AMA-1 gene of P. knowlesi clinical isolates from Peninsular Malaysia was amplified by PCR, cloned into Escherichia coli, then sequenced and analysed. Ninety-seven DI domain sequences were obtained. Comparison at the nucleotide level against P. knowlesi strain H as reference sequence showed 21 synonymous and 25 nonsynonymous mutations. Nonetheless, nucleotide sequence analysis revealed low genetic diversity of the DI domain, and it was under purifying (negative) selection. At the amino acid level, 26 different haplotypes were identified and 2 were predominant haplotypes (H1, H2) with high frequencies. Phylogenetic analysis revealed that the 26 haplotypes could be clustered into 2 distinct groups (I and II). Members of the groups were basically derived from haplotypes H1 and H2, respectively.
    Matched MeSH terms: Membrane Proteins/genetics*
  8. Salahshourifar I, Vincent-Chong VK, Chang HY, Ser HL, Ramanathan A, Kallarakkal TG, et al.
    Clin Oral Investig, 2015 Dec;19(9):2273-83.
    PMID: 25846277 DOI: 10.1007/s00784-015-1467-7
    OBJECTIVES: This study includes the direct sequencing of cornulin (CRNN) gene to elucidate the possible mechanism of CRNN downregulation and explore the genetic imbalances at 1q21.3 across oral squamous cell carcinoma (OSCC) samples.

    MATERIALS AND METHODS: In mutation screening of CRNN gene, gDNA from OSCC tissues were extracted, amplified, and followed by direct sequencing. OSCC samples were also subjected to fragment analysis on CRNN gene to investigate its microsatellite instability (MSI) and loss of heterozygosity (LOH). Immunohistochemistry was performed to validate CRNN downregulation in OSCC samples.

    RESULTS: No pathogenic mutation was found in CRNN gene, while high frequency of allelic imbalances was found at 1q21.3 region. MSI was found more frequent (25.3 %) than LOH (9.3 %). Approximately 22.6 % of cases had high MSI which reflects higher probability of inactivation of DNA mismatch repair genes. MSI showed significant association with no betel quid chewing (p = 0.003) and tongue subsite (p = 0.026). LOH was associated with ethnicity (p = 0.008) and advanced staging (p = 0.039). The LOH at 1q21.3 was identified to be as an independent prognostic marker in OSCC (HRR = 7.15 (95 % CI, 1.41-36.25), p = 0.018). Downregulation of CRNN was found among MSI-positive OSCCs and was associated with poor prognosis (p = 0.044).

    CONCLUSION: This study showed a significant correlation between LOH/MSI at 1q21.3 with clinical outcomes and that downregulation of CRNN gene could be considered as a prognostic marker of OSCC.

    CLINICAL RELEVANCE: Insights of the downregulation mode of CRNN gene lays the basis of drug development on this gene as well as revealing its prognostic value.

    Matched MeSH terms: Membrane Proteins/genetics*
  9. Berki DM, Liu L, Choon SE, David Burden A, Griffiths CEM, Navarini AA, et al.
    J Invest Dermatol, 2015 Dec;135(12):2964-2970.
    PMID: 26203641 DOI: 10.1038/jid.2015.288
    Caspase recruitment family member 14 (CARD14, also known as CARMA2), is a scaffold protein that mediates NF-κB signal transduction in skin keratinocytes. Gain-of-function CARD14 mutations have been documented in familial forms of psoriasis vulgaris (PV) and pityriasis rubra pilaris (PRP). More recent investigations have also implicated CARD14 in the pathogenesis of pustular psoriasis. Follow-up studies, however, have been limited, so that it is not clear to what extent CARD14 alleles account for the above conditions. Here, we sought to address this question by carrying out a systematic CARD14 analysis in an extended patient cohort (n=416). We observed no disease alleles in subjects with familial PV (n=159), erythrodermic psoriasis (n=23), acral pustular psoriasis (n=100), or sporadic PRP (n=29). Conversely, our analysis of 105 individuals with generalized pustular psoriasis (GPP) identified a low-frequency variant (p.Asp176His) that causes constitutive CARD14 oligomerization and shows a significant association with GPP in Asian populations (P=8.4×10(-5); odds ratio=6.4). These data indicate that the analysis of CARD14 mutations could help stratify pustular psoriasis cohorts but would be mostly uninformative in the context of psoriasis and sporadic PRP.
    Matched MeSH terms: Membrane Proteins/genetics*
  10. 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.
    Matched MeSH terms: Membrane Proteins/genetics*
  11. Ahmed MA, Quan FS
    Malar J, 2019 Apr 29;18(1):150.
    PMID: 31035999 DOI: 10.1186/s12936-019-2782-2
    BACKGROUND: The high proportion of human cases due to the simian malaria parasite Plasmodium knowlesi in Malaysia is a cause of concern, as they can be severe and even fatal. Merozoite surface protein 7 (MSP7) is a multigene family which forms a non-covalent complex with MSP-1 prior to receptor-ligand recognition in Plasmodium falciparum and thus an important antigen for vaccine development. However, no study has been done in any of the ortholog family members in P. knowlesi from clinical samples. This study investigates the level of polymorphism, haplotypes, and natural selection acting at the pkmsp-7D gene in clinical samples from Malaysia.

    METHODS: Thirty-six full-length pkmsp7D gene sequences (along with the reference H-strain: PKNH_1266000) obtained from clinical isolates of Malaysia, which were orthologous to pvmsp7H (PVX_082680) were downloaded from public databases. Population genetic, evolutionary and phylogenetic analyses were performed to determine the level of genetic diversity, polymorphism, recombination and natural selection.

    RESULTS: Analysis of 36 full-length pkmsp7D sequences identified 147 SNPs (91 non-synonymous and 56 synonymous substitutions). Nucleotide diversity across the full-length gene was higher than its ortholog in Plasmodium vivax (msp7H). Region-wise analysis of the gene indicated that the nucleotide diversity at the central region was very high (π = 0.14) compared to the 5' and 3' regions. Most hyper-variable SNPs were detected at the central domain. Multiple test for natural selection indicated the central region was under strong positive natural selection however, the 5' and 3' regions were under negative/purifying selection. Evidence of intragenic recombination were detected at the central region of the gene. Phylogenetic analysis using full-length msp7D genes indicated there was no geographical clustering of parasite population.

    CONCLUSIONS: High genetic diversity with hyper-variable SNPs and strong evidence of positive natural selection at the central region of MSP7D indicated exposure of the region to host immune pressure. Negative selection at the 5' and the 3' regions of MSP7D might be because of functional constraints at the unexposed regions during the merozoite invasion process of P. knowlesi. No evidence of geographical clustering among the clinical isolates from Malaysia indicated uniform selection pressure in all populations. These findings highlight the further evaluation of the regions and functional characterization of the protein as a potential blood stage vaccine candidate for P. knowlesi.

    Matched MeSH terms: Membrane Proteins/genetics*
  12. Amjad N, Osman HA, Razak NA, Kassian J, Din J, bin Abdullah N
    World J Gastroenterol, 2010 Sep 21;16(35):4443-7.
    PMID: 20845512
    AIM: To study the presence of Helicobacter pylori (H. pylori) virulence factors and clinical outcome in H. pylori infected patients.

    METHODS: A prospective analysis of ninety nine H. pylori-positive patients who underwent endoscopy in our Endoscopy suite were included in this study. DNA was isolated from antral biopsy samples and the presence of cagA, iceA, and iceA2 genotypes were determined by polymerase chain reaction and a reverse hybridization technique. Screening for H. pylori infection was performed in all patients using the rapid urease test (CLO-Test).

    RESULTS: From a total of 326 patients who underwent endoscopy for upper gastrointestinal symptoms, 99 patients were determined to be H. pylori-positive. Peptic ulceration was seen in 33 patients (33%). The main virulence strain observed in this cohort was the cagA gene isolated in 43 patients. cagA was associated with peptic ulcer pathology in 39.5% (17/43) and in 28% (16/56) of non-ulcer patients. IceA1 was present in 29 patients (29%) and iceA2 in 15 patients (15%). Ulcer pathology was seen in 39% (11/29) of patients with iceA1, while 31% (22/70) had normal findings. The corresponding values for iceA2 were 33% (5/15) and 33% (28/84), respectively.

    CONCLUSION: Virulence factors were not common in our cohort. The incidence of factors cagA, iceA1 and iceA2 were very low although variations were noted in different ethnic groups.

    Matched MeSH terms: Bacterial Outer Membrane Proteins/genetics*
  13. Wong KC, Lai MY, De Silva JR, Cheong FW, Fong MY, Lau YL
    Trop Biomed, 2021 Jun 01;38(2):143-148.
    PMID: 34172703 DOI: 10.47665/tb.38.2.051
    Normocyte binding protein Xa (NBPXa) has been implied to play a significant role in parasite invasion of human erythrocytes. Previous phylogenetic studies have reported the existence of three types of NBPXa for Plasmodium knowlesi (PkNBPXa). PkNBPXa region II (PkNBPXaII) of type 1, type 2 and type 3 were expressed on mammalian cell surface and interacted with human and macaque (Macaca fascicularis) erythrocytes. The binding activities of PkNBPXaII towards human and macaque erythrocytes were evaluated using erythrocyte-binding assay (EBA). Three parameters were evaluated to achieve the optimal protein expression of PkNBPXaII and erythrocyte binding activity in EBA: types of mammalian cells, post transfection time and erythrocyte incubation time. COS-7, HEK-293, and CHO-K1 cells showed successful expression of PkNBPXaII, despite the protein expression is weak compared to the positive control. COS-7 was used in EBA. All three types of PkNBPXaII showed rosette formation with macaque erythrocytes but not with human erythrocytes. Future studies to enhance the PkNBPXaII expression on surface of mammalian cells is indeed needed in order to elucidate the specific role of PkNBPXaII in erythrocytes invasion.
    Matched MeSH terms: Membrane Proteins/genetics
  14. Gitaka JN, Takeda M, Kimura M, Idris ZM, Chan CW, Kongere J, et al.
    Malar J, 2017 03 02;16(1):98.
    PMID: 28253868 DOI: 10.1186/s12936-017-1743-x
    BACKGROUND: Plasmodium falciparum SURFIN4.1is a putative ligand expressed on the merozoite and likely on the infected red blood cell, whose gene was suggested to be under directional selection in the eastern Kenyan population, but under balancing selection in the Thai population. To understand this difference, surf4.1sequences of western Kenyan P. falciparum isolates were analysed. Frameshift mutations and copy number variation (CNV) were also examined for the parasites from western Kenya and Thailand.

    RESULTS: Positively significant departures from neutral expectations were detected on the surf4.1region encoding C-terminus of the variable region 2 (Var2) by 3 population-based tests in the western Kenyan population as similar in the Thai population, which was not covered by the previous analysis for eastern Kenyan population. Significant excess of non-synonymous substitutions per nonsynonymous site over synonymous substitutions per synonymous site was also detected in the Var2 region. Negatively significant departures from neutral expectations was detected on the region encoding Var1 C-terminus consistent to the previous observation in the eastern Kenyan population. Parasites possessing a frameshift mutation resulting a product without intracellular Trp-rich (WR) domains were 22/23 in western Kenya and 22/36 in Thailand. More than one copy of surf4.1gene was detected in western Kenya (4/24), but no CNV was found in Thailand (0/36).

    CONCLUSIONS: The authors infer that the high polymorphism of SURFIN4.1Var2 C-terminus in both Kenyan and Thai populations were shaped-up by diversifying selection and maintained by balancing selection. These phenomena were most likely driven by immunological pressure. Whereas the SURFIN4.1Var1 C-terminus is suggested to be under directional selection consistent to the previous report for the eastern Kenyan population. Most western Kenyan isolates possess a frameshift mutation that would limit the expression of SURFIN4.1on the merozoite, but only 60% of Thai isolates possess this frameshift, which would affect the level and type of the selection pressure against this protein as seen in the two extremities of Tajima's D values for Var1 C-terminus between Kenyan and Thai populations. CNV observed in Kenyan isolates may be a consequence of this frameshift mutation to increase benefits on the merozoite surface.

    Matched MeSH terms: Membrane Proteins/genetics*
  15. Yazid MD, Zainal Ariffin SH, Senafi S, Zainal Ariffin Z, Megat Abdul Wahab R
    ScientificWorldJournal, 2011;11:2150-9.
    PMID: 22125464 DOI: 10.1100/2011/340278
    The main purpose of this paper was to determine the heterogeneity of primary isolated mononucleated cells that originated from the peripheral blood system by observing molecular markers. The isolated cells were cultured in complete medium for 4 to 7 days prior to the separation of different cell types, that is, adherent and suspension. Following a total culture time of 14 days, adherent cells activated the Cd105 gene while suspension cells activated the Sca-1 gene. Both progenitor markers, Cbfa-1 and Ostf-1, were inactivated in both suspension and adherent cells after 14-day culture compared to cells cultured 3 days in designated differentiation medium. In conclusion, molecular analyses showed that primary mononucleated cells are heterogeneous, consisting of hematopoietic stem cells (suspension) and mesenchymal stem cells (adherent) while both cells contained no progenitor cells.
    Matched MeSH terms: Membrane Proteins/genetics
  16. Kaiyrzhanov R, Mohammed SEM, Maroofian R, Husain RA, Catania A, Torraco A, et al.
    Am J Hum Genet, 2022 Sep 01;109(9):1692-1712.
    PMID: 36055214 DOI: 10.1016/j.ajhg.2022.07.007
    Leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) encodes an inner mitochondrial membrane protein with an osmoregulatory function controlling mitochondrial volume and ion homeostasis. The putative association of LETM1 with a human disease was initially suggested in Wolf-Hirschhorn syndrome, a disorder that results from de novo monoallelic deletion of chromosome 4p16.3, a region encompassing LETM1. Utilizing exome sequencing and international gene-matching efforts, we have identified 18 affected individuals from 11 unrelated families harboring ultra-rare bi-allelic missense and loss-of-function LETM1 variants and clinical presentations highly suggestive of mitochondrial disease. These manifested as a spectrum of predominantly infantile-onset (14/18, 78%) and variably progressive neurological, metabolic, and dysmorphic symptoms, plus multiple organ dysfunction associated with neurodegeneration. The common features included respiratory chain complex deficiencies (100%), global developmental delay (94%), optic atrophy (83%), sensorineural hearing loss (78%), and cerebellar ataxia (78%) followed by epilepsy (67%), spasticity (53%), and myopathy (50%). Other features included bilateral cataracts (42%), cardiomyopathy (36%), and diabetes (27%). To better understand the pathogenic mechanism of the identified LETM1 variants, we performed biochemical and morphological studies on mitochondrial K+/H+ exchange activity, proteins, and shape in proband-derived fibroblasts and muscles and in Saccharomyces cerevisiae, which is an important model organism for mitochondrial osmotic regulation. Our results demonstrate that bi-allelic LETM1 variants are associated with defective mitochondrial K+ efflux, swollen mitochondrial matrix structures, and loss of important mitochondrial oxidative phosphorylation protein components, thus highlighting the implication of perturbed mitochondrial osmoregulation caused by LETM1 variants in neurological and mitochondrial pathologies.
    Matched MeSH terms: Membrane Proteins/genetics
  17. Apalasamy YD, Moy FM, Rampal S, Bulgiba A, Mohamed Z
    Genet. Mol. Res., 2014;13(3):4904-10.
    PMID: 25062423 DOI: 10.4238/2014.July.4.4
    A genome-wide association study showed that the tagging single nucleotide polymorphism (SNP) rs7566605 in the insulin-induced gene 2 (INSIG2) was associated with obesity. Attempts to replicate this result in different populations have produced inconsistent findings. We aimed to study the association between the rs7566605 SNP with obesity and other metabolic parameters in Malaysian Malays. Anthropometric and obesity-related metabolic parameters and DNA samples were collected. We genotyped the rs7566605 polymorphism in 672 subjects using real-time polymerase chain reaction. No significant associations were found between the rs7566605 tagging SNP of INSIG2 with obesity or other metabolic parameters in the Malaysian Malay population. The INSIG2 rs7566605 SNP may not play a role in the development of obesity-related metabolic traits in Malaysian Malays.
    Matched MeSH terms: Membrane Proteins/genetics*
  18. Lau YL, Fong MY, Mahmud R, Chang PY, Palaeya V, Cheong FW, et al.
    Malar J, 2011;10:197.
    PMID: 21774805 DOI: 10.1186/1475-2875-10-197
    The emergence of Plasmodium knowlesi in humans, which is in many cases misdiagnosed by microscopy as Plasmodium malariae due to the morphological similarity has contributed to the needs of detection and differentiation of malaria parasites. At present, nested PCR targeted on Plasmodium ssrRNA genes has been described as the most sensitive and specific method for Plasmodium detection. However, this method is costly and requires trained personnel for its implementation. Loop-mediated isothermal amplification (LAMP), a novel nucleic acid amplification method was developed for the clinical detection of P. knowlesi. The sensitivity and specificity of LAMP was evaluated in comparison to the results obtained via microscopic examination and nested PCR.
    Matched MeSH terms: Membrane Proteins/genetics
  19. Lokanathan Y, Mohd-Adnan A, Wan KL, Nathan S
    BMC Genomics, 2010;11:76.
    PMID: 20113487 DOI: 10.1186/1471-2164-11-76
    Cryptocaryon irritans is a parasitic ciliate that causes cryptocaryonosis (white spot disease) in marine fish. Diagnosis of cryptocaryonosis often depends on the appearance of white spots on the surface of the fish, which are usually visible only during later stages of the disease. Identifying suitable biomarkers of this parasite would aid the development of diagnostic tools and control strategies for C. irritans. The C. irritans genome is virtually unexplored; therefore, we generated and analyzed expressed sequence tags (ESTs) of the parasite to identify genes that encode for surface proteins, excretory/secretory proteins and repeat-containing proteins.
    Matched MeSH terms: Membrane Proteins/genetics
  20. Aziah I, Ravichandran M, Ismail A
    Diagn Microbiol Infect Dis, 2007 Dec;59(4):373-7.
    PMID: 17964105
    Conventional polymerase chain reaction (PCR) testing requires many pipetting steps and has to be transported and stored in cold chain. To overcome these limitations, we designed a ready-to-use PCR test for Salmonella typhi using PCR reagents, primers against the ST50 gene of S. typhi, a built-in internal amplification control (IAC), and gel loading dye mixed and freeze-dried in a single tube. The 2-step dry-reagent-based assay was used to amplify a 1238-bp target gene and an 810-bp IAC gene from 73 BACTEC blood culture broths (33 true positives for S. typhi and 40 true negatives for non-S. typhi). The sensitivity, specificity, positive predictive value, and negative predictive value of the PCR assay were 87.9%, 100%, 100%, and 90.9%, respectively. We suggest that this rapid 2-step PCR test could be used for the rapid diagnosis of typhoid fever.
    Matched MeSH terms: Bacterial Outer Membrane Proteins/genetics*
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