Displaying publications 1 - 20 of 62 in total

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  1. Rueppell O, Kuster R, Miller K, Fouks B, Rubio Correa S, Collazo J, et al.
    Genome Biol Evol, 2016 12 01;8(12):3653-3660.
    PMID: 28173114 DOI: 10.1093/gbe/evw269
    Western honey bees (Apis mellifera) far exceed the commonly observed 1–2 meiotic recombination events per chromosome and exhibit the highest Metazoan recombination rate (20 cM/Mb) described thus far. However, the reasons for this exceptional rate of recombination are not sufficiently understood. In a comparative study, we report on the newly constructed genomic linkage maps of Apis florea and Apis dorsata that represent the two honey bee lineages without recombination rate estimates so far. Each linkage map was generated de novo, based on SNP genotypes of haploid male offspring of a single female. The A. florea map spans 4,782 cM with 1,279 markers in 16 linkage groups. The A. dorsata map is 5,762 cM long and contains 1,189 markers in 16 linkage groups. Respectively, these map sizes result in average recombination rate estimates of 20.8 and 25.1 cM/Mb. Synteny analyses indicate that frequent intra-chromosomal rearrangements but no translocations among chromosomes accompany the high rates of recombination during the independent evolution of the three major honey bee lineages. Our results imply a common cause for the evolution of very high recombination rates in Apis. Our findings also suggest that frequent homologous recombination during meiosis might increase ectopic recombination and rearrangements within but not between chromosomes. It remains to be investigated whether the resulting inversions may have been important in the evolutionary differentiation between honey bee species.
    Matched MeSH terms: Recombination, Genetic*
  2. Chow WZ, Takebe Y, Syafina NE, Prakasa MS, Chan KG, Al-Darraji HA, et al.
    PLoS One, 2014;9(1):e85250.
    PMID: 24465513 DOI: 10.1371/journal.pone.0085250
    The HIV epidemic is primarily characterised by the circulation of HIV-1 group M (main) comprising of 11 subtypes and sub-subtypes (A1, A2, B-D, F1, F2, G, H, J, and K) and to date 55 circulating recombinant forms (CRFs). In Southeast Asia, active inter-subtype recombination involving three main circulating genotypes--subtype B (including subtype B', the Thai variant of subtype B), CRF01_AE, and CRF33_01B--have contributed to the emergence of novel unique recombinant forms. In the present study, we conducted the molecular epidemiological surveillance of HIV-1 gag-RT genes among 258 people who inject drugs (PWIDs) in Kuala Lumpur, Malaysia, between 2009 and 2011 whereby a novel CRF candidate was recently identified. The near full-length genome sequences obtained from six epidemiologically unlinked individuals showed identical mosaic structures consisting of subtype B' and CRF01_AE, with six unique recombination breakpoints in the gag-RT, pol, and env regions. Among the high-risk population of PWIDs in Malaysia, which was predominantly infected by CRF33_01B (>70%), CRF58_01B circulated at a low but significant prevalence (2.3%, 6/258). Interestingly, the CRF58_01B shared two unique recombination breakpoints with other established CRFs in the region: CRF33_01B, CRF48_01B, and CRF53_01B in the gag gene, and CRF15_01B (from Thailand) in the env gene. Extended Bayesian Markov chain Monte Carlo sampling analysis showed that CRF58_01B and other recently discovered CRFs were most likely to have originated in Malaysia, and that the recent spread of recombinant lineages in the country had little influence from neighbouring countries. The isolation, genetic characterization, and evolutionary features of CRF58_01B among PWIDs in Malaysia signify the increasingly complex HIV-1 diversity in Southeast Asia that may hold an implication on disease treatment, control, and prevention.
    Matched MeSH terms: Recombination, Genetic
  3. Lim SP, Pandikumar A, Lim HN, Ramaraj R, Huang NM
    Sci Rep, 2015;5:11922.
    PMID: 26146362 DOI: 10.1038/srep11922
    A silver nanoparticle-decorated N,S-co-doped TiO2 nanocomposite was successfully prepared and used as an efficient photoanode in high-performance dye-sensitized solar cells (DSSCs) with N719 dye. The DSSCs assembled with the N,S-TiO2@Ag-modified photoanode demonstrated an enhanced solar-to-electrical energy conversion efficiency of 8.22%, which was better than that of a DSSC photoanode composed of unmodified TiO2 (2.57%) under full sunlight illumination (100 mWcm(-2), AM 1.5 G). This enhanced efficiency was mainly attributed to the reduced band gap energy, improved interfacial charge transfer, and retarded charge recombination process. The influence of the Ag content on the overall efficiency was also investigated, and the optimum Ag content with N,S-TiO2 was found to be 20 wt%. Because of the enhanced solar energy conversion efficiency of the N,S-TiO2@Ag nanocomposite, it should be considered as a potential photoanode for high-performance DSSCs.
    Matched MeSH terms: Recombination, Genetic
  4. Mandary MB, Poh CL
    Viruses, 2018 06 12;10(6).
    PMID: 29895721 DOI: 10.3390/v10060320
    Enterovirus 71 (EV-A71) is a major etiological agent of hand, foot and mouth disease (HFMD) that mainly affects young children less than five years old. The onset of severe HFMD is due to neurological complications bringing about acute flaccid paralysis and pulmonary oedema. In this review, we address how genetic events such as recombination and spontaneous mutations could change the genomic organization of EV-A71, leading to an impact on viral virulence. An understanding of the recombination mechanism of the poliovirus and non-polio enteroviruses will provide further evidence of the emergence of novel strains responsible for fatal HFMD outbreaks. We aim to see if the virulence of EV-A71 is contributed solely by the presence of fatal strains or is due to the co-operation of quasispecies within a viral population. The phenomenon of quasispecies within the poliovirus is discussed to reflect viral fitness, virulence and its implications for EV-A71. Ultimately, this review gives an insight into the evolution patterns of EV-A71 by looking into its recombination history and how spontaneous mutations would affect its virulence.
    Matched MeSH terms: Recombination, Genetic*
  5. Ng CK, How KY, Tee KK, Chan KG
    Genes (Basel), 2019 04 08;10(4).
    PMID: 30965610 DOI: 10.3390/genes10040282
    Quorum sensing (QS) is a cell-to-cell communication system that uses autoinducers as signaling molecules to enable inter-species and intra-species interactions in response to external stimuli according to the population density. QS allows bacteria such as Acinetobacter baumannii to react rapidly in response to environmental changes and hence, increase the chances of survival. A. baumannii is one of the causative agents in hospital-acquired infections and the number of cases has increased remarkably in the past decade. In this study, A. baumannii strain 863, a multidrug-resistant pathogen, was found to exhibit QS activity by producing N-acyl homoserine lactone. We identified the autoinducer synthase gene, which we named abaI, by performing whole genome sequencing analysis of A. baumannii strain 863. Using high resolution tandem triple quadrupole mass spectrometry, we reported that abaI of A. baumannii strain 863 produced 3-hydroxy-dodecanoyl-homoserine lactone. A gene deletion mutant was constructed, which confirmed the functionality of abaI. A growth defect was observed in the QS-deficient mutant strain. Transcriptome profiling was performed to determine the possible genes regulated by QS. Four groups of genes that showed differential expression were discovered, namely those involved in carbon source metabolism, energy production, stress response and the translation process.
    Matched MeSH terms: Recombination, Genetic/genetics
  6. Lasekan O, Dabaj F, Muniandy M, Juhari NH, Lasekan A
    BMC Chem, 2021 Mar 13;15(1):16.
    PMID: 33714268 DOI: 10.1186/s13065-021-00743-4
    BACKGROUND: To evaluate the impact of cold fermentation time on bagel rolls, the key aroma-active compounds in the volatile fractions obtained from three different bagel rolls through solvent assisted flavor evaporation (SAFE) were sequentially characterized by an aroma extract dilution analysis (AEDA), quantified by stable isotope dilution and analyzed by odor activity values (OAVs) respectively.

    RESULTS: Findings revealed 40 aroma-active compounds with flavor dilution (FD) factor ranges of 2-1024. Of these, 22 compounds (FD ≥ 16) were quantified by stable isotope dilution assays (SIDA). Subsequent analysis of the 22 compounds by odor activity values (OAVs) revealed 14 compounds with OAVs ≥ 1 and the highest concentrations were obtained for 2,3-butanedione, 2-phenylethanol, 3-methylbutanal and acetoin respectively. Two recombination models of the bagels (i.e. 24 h and 48 h bagels) showed similarity to the corresponding bagels. Omission tests confirmed that 2,3-butanedione (buttery), acetoin (buttery), 2-acetyl-1-pyrroline (roasty), 5-methyl-2-furanmethanol (bread-like), (Z)-4-heptenal (biscuit-like) and 4-hydroxy-2,5-dimethyl-3(2H)-furanone, were the key aroma compounds. Additionally, acetic acid, butanoic acid, 2-phenylethanol (honey-like), 3-methylbutanoic acid, 2/3-methylbutanal, vanillin, 3-methylbutanol, methional were also important odorants of the bagel.

    CONCLUSION: Whilst the long, cold fermented bagels exhibited roasty, malty, buttery, baked potato-like, smoky and biscuit-like notes, the control bagels produced similar but less intense odor notes.

    Matched MeSH terms: Recombination, Genetic
  7. Lau YL, Hasan MT, Thiruvengadam G, Idris MM, Init I
    Trop Biomed, 2010 Dec;27(3):525-33.
    PMID: 21399595
    GRA4 of Toxoplasma gondii has been shown to prompt IgG, IgM and IgA responses in previous studies and is thus considered one of the major immunogenic proteins from T. gondii that can be used for both diagnostics purposes and vaccine development. This study seeks to clone and express the GRA4 in Pichia pastoris, which has numerous advantages over other systems for expression of eukaryotic proteins. In order to achieve this, the gene was cloned into the pPICZα A expression vector, which was then incorporated into the P. pastoris genome via insertional integration for expression of the recombinant protein, under the AOX1 promoter. The antigen was expressed along with the prepro sequence of the α-factor of yeast so that it could be excreted out of the P. pastoris cells and obtained from the medium. Upon SDS-PAGE analysis it was found that the recombinant protein was expressed optimally as a 40 kDa protein after 96 hours of induction with 0.75% of methanol. The expressed GRA4 protein showed discrepancy in size with the calculated molecular mass. This may be attributed to the various posttranslational modifications including glycosylation and phosphorylation. Despite the difference in molecular weight, the recombinant protein was able to detect toxoplasmosis in Western blot format. The recombinant GRA4 was expressed with an intact polyhistidine-tag, which could be used for future purification of the antigen.
    Matched MeSH terms: Recombination, Genetic
  8. Chan YF, Wee KL, Chiam CW, Khor CS, Chan SY, Amalina W MZ, et al.
    Trop Biomed, 2012 Sep;29(3):451-66.
    PMID: 23018509 MyJurnal
    Three genomic regions, VP4 capsid, VP1 capsid and 3D RNA polymerase of human enterovirus 71 (EV-71) and coxsackievirus A16 (CV-A16) were sequenced to understand the evolution of these viruses in Malaysia. A total of 42 EV-71 and 36 CV-A16 isolates from 1997- 2008 were sequenced. Despite the presence of many EV-71 subgenotypes worldwide, only subgenotypes B3, B4, B5, C1 and C2 were present in Malaysia. Importation of other subgenotypes such as C3, C4/D and C5 from other countries was infrequent. For CV-A16, the earlier subgenotype B1 was replaced by subgenotypes B2a and the recent B2c. Subgenotype B2a was present throughout the study while B2c only emerged in 2005. No genetic signatures could be attributed to viral virulence suggesting that host factors have a major role in determining the outcome of infection. Only three EV-71 B3 isolates showed non-consistent phylogeny in the 3D RNA polymerase region which indicated occurrence of recombination in EV-71. High genetic diversity was observed in the Malaysian EV-71 but Malaysian CV-A16 showed low genetic diversity in the three genomic regions sequenced. EV-71 showed strong purifying selection, but that occurred to a lesser extent in CV-A16.
    Matched MeSH terms: Recombination, Genetic
  9. Moss B, Lim KK, Beltram A, Moniz S, Tang J, Fornasiero P, et al.
    Sci Rep, 2017 06 07;7(1):2938.
    PMID: 28592816 DOI: 10.1038/s41598-017-03065-5
    In this article we present the first comparative study of the transient decay dynamics of photo-generated charges for the three polymorphs of TiO2. To our knowledge, this is the first such study of the brookite phase of TiO2 over timescales relevant to the kinetics of water splitting. We find that the behavior of brookite, both in the dynamics of relaxation of photo-generated charges and in energetic distribution, is similar to the anatase phase of TiO2. Moreover, links between the rate of recombination of charge carriers, their energetic distribution and the mode of transport are made in light of our findings and used to account for the differences in water splitting efficiency observed across the three polymorphs.
    Matched MeSH terms: Recombination, Genetic
  10. Ishikawa T, Abe M, Masuda M
    Virus Res, 2015 Jan 2;195:153-61.
    PMID: 25451067 DOI: 10.1016/j.virusres.2014.10.010
    Japanese encephalitis virus (JEV) genotype V was originally isolated in Malaysia in 1952 and has long been restricted to the area. In 2009, sudden emergence of the genotype V in China and Korea was reported, suggesting expansion of its geographical distribution. Although studies on the genotype V are becoming more important, they have been limited partly due to lack of its infectious molecular clone. In this study, a plasmid carrying cDNA corresponding to the entire genome of JEV Muar strain, which belongs to genotype V, in the downstream of T7 promoter was constructed. Electroporation of viral RNA transcribed by T7 RNA polymerase (T7RNAP) in vitro from the plasmid led to production of progeny viruses both in mammalian and mosquito cells. Also, transfection of the infectious clone plasmid into mammalian cells expressing T7RNAP transiently or stably was demonstrated to generate infectious progenies. When the viral structural protein genes were partially deleted from the full-length cDNA, the subgenomic RNA transcribed in vitro from the modified plasmid was shown to replicate itself in mammalian cells as a replicon. The replicon carrying the firefly luciferase gene in place of the deleted structural protein genes was also shown to efficiently replicate itself and express luciferase in mammalian cells. Compared with the replicon derived from JEV genotype III (Nakayama strain), the genotype V-derived replicon appeared to be more tolerant to introduction of a foreign gene. The infectious clone and the replicons constructed in this study may serve as useful tools for characterizing JEV genotype V.
    Matched MeSH terms: Recombination, Genetic*
  11. Lau KA, Wang B, Kamarulzaman A, Ngb KP, Saksena NK
    Curr. HIV Res., 2008 Mar;6(2):108-16.
    PMID: 18336258
    The Asian HIV epidemic appears to be complex, characterized by the prevalence of multiple subtypes and circulating recombinant forms with gradual replacement of pure HIV-1 subtypes in several geographical regions. The main objectives of the present study are to identify and analyse the full-length viral genomes of three unique recombinant forms (URFs); the HIV-1 isolates 07MYKLD47, 07MYKLD48 and 07MYKLD49 from Malaysia. Long-range polymerase chain reaction (PCR) amplification of seven overlapping reading frames was used to derive near full-length HIV-1 genomes. Detailed phylogenetic and bootscanning analyses were performed to determine phylogenetic associations and subtypic assignments. We further confirmed the mosaic composition of these CRF01_AE/B inter-subtype recombinant forms, which are composed of B-subtype fragment(s) in the backbone of CRF01_AE. Both 07MYKLD47 and 07MYKLD48 have an insertion of B subtype (880 bp and 532 bp) in the gag-pol and gp41-env gene regions, respectively. Whereas the isolate 07MYKLD49 has three B-subtype fragments inserted in different gene region along the genome; one each in the gag-pol (1862 bp) and pol-vif (1935 bp) regions, and a short B-subtype insertion (541 bp) in the 5' LTR-gag region. This highlights the public health relevance of newly emerging second generation HIV-1 recombinant forms and their dispersal, along with their rapid and continuous evolution in the region.
    Matched MeSH terms: Recombination, Genetic*
  12. Lai CW, Lau KS, Chou PM
    J Nanosci Nanotechnol, 2019 Dec 01;19(12):7934-7942.
    PMID: 31196312 DOI: 10.1166/jnn.2019.16777
    Using solar-powered water electrolysis systems for hydrogen generation is a key decision for the development of a sustainable hydrogen economy. A facile approach is presented in the present investigation to improve the solar-powered photoelectrochemical performance of water electrolysis systems by synthesising well-aligned and highly ordered TiO₂ nanotube films without bundling through the electrochemical anodisation technique. Herein, geometrical calculations were conducted for all synthesised TiO₂ nanotubes, and determination of the aspect ratio (AR) and geometric surface area factor (G) was achieved. On the basis of the collected data, well-aligned TiO₂ nanotubes with an AR of approximately 60 and G of approximately 400 m² ·g-1 were successfully formed in an electrolyte mixture of ethylene glycol with 0.3 wt% NH4F and 5 wt% H₂O₂ at 40 V for 60 min. The nanotubes were subsequently annealed at 400 °C to form anatase-phase TiO₂ nanotube films. The resultant well-aligned and highly ordered TiO₂ nanotube films exhibited a photocurrent density of 1.5 mA · cm-2 due to a large number of photo-induced electrons moving along the tube axis and perpendicular to the Ti substrate, which greatly reduces interfacial recombination losses.
    Matched MeSH terms: Recombination, Genetic
  13. Abd Samad NA, Lai CW, Lau KS, Abd Hamid SB
    Materials (Basel), 2016 Nov 22;9(11).
    PMID: 28774068 DOI: 10.3390/ma9110937
    Efficient solar driven photoelectrochemical (PEC) response by enhancing charge separation has attracted great interest in the hydrogen generation application. The formation of one-dimensional ZnO nanorod structure without bundling is essential for high efficiency in PEC response. In this present research work, ZnO nanorod with an average 500 nm in length and average diameter of about 75 nm was successfully formed via electrodeposition method in 0.05 mM ZnCl₂ and 0.1 M KCl electrolyte at 1 V for 60 min under 70 °C condition. Continuous efforts have been exerted to further improve the solar driven PEC response by incorporating an optimum content of TiO₂ into ZnO nanorod using dip-coating technique. It was found that 0.25 at % of TiO₂ loaded on ZnO nanorod film demonstrated a maximum photocurrent density of 19.78 mA/cm² (with V vs. Ag/AgCl) under UV illumination and 14.75 mA/cm² (with V vs. Ag/AgCl) under solar illumination with photoconversion efficiency ~2.9% (UV illumination) and ~4.3% (solar illumination). This performance was approximately 3-4 times higher than ZnO film itself. An enhancement of photocurrent density and photoconversion efficiency occurred due to the sufficient Ti element within TiO₂-ZnO nanorod film, which acted as an effective mediator to trap the photo-induced electrons and minimize the recombination of charge carriers. Besides, phenomenon of charge-separation effect at type-II band alignment of Zn and Ti could further enhance the charge carrier transportation during illumination.
    Matched MeSH terms: Recombination, Genetic
  14. Tee KK, Pon CK, Kamarulzaman A, Ng KP
    AIDS, 2005 Jan 28;19(2):119-26.
    PMID: 15668536
    OBJECTIVES: To investigate the molecular epidemiology of HIV-1 and to screen for the emergence of intersubtype recombinants in Kuala Lumpur, Malaysia.

    DESIGN: A molecular epidemiology study was conducted among HIV-1 seropositive patients attending the University Malaya Medical Center (UMMC) from July 2003 to June 2004.

    METHODS: Protease (PR) and reverse transcriptase (RT) gene sequences were derived from drug resistance genotyping assay of 100 newly diagnosed or antiretroviral-naive patients. These were phylogenetically analysed to determine the subtypes and recombination breakpoint analyses were performed on intersubtype recombinants to estimate the recombination breakpoint(s).

    RESULTS: CRF01_AE predominated in Kuala Lumpur with 65% in both PR and RT genes. B subtype was detected at 14% and 12% in PR and RT genes, respectively. C subtype was present at 1% in both genes. Overall, the concordance of PR and RT genes in discriminating subtypes/circulating recombinant forms (CRF) was high at 96%. In this study, novel CRF01_AE/B intersubtype recombinants were detected at high prevalence (22%), including those isolates with subtype discordance. Thai variants of CRF01_AE and B subtype were involved in the genesis of these unique recombinant forms (URF). Interestingly, 19 CRF01_AE/B intersubtype recombinant isolates shared similar recombination breakpoints in both PR and RT genes. Several distinct URF were also identified.

    CONCLUSION: PR and RT genes can be utilized for subtype/CRF assessment with high degree of agreement, allowing concurrent surveillance of circulating HIV-1 subtypes with antiretroviral drug resistance genotyping tests. The emergence of highly identical CRF01_AE/B intersubtype recombinants suggests the possibility of the appearance of a new circulating recombinant form in Kuala Lumpur.

    Matched MeSH terms: Recombination, Genetic/genetics*
  15. Tan KH, Chen YW, Van CN, Wang H, Chen JW, Lim FS, et al.
    ACS Appl Mater Interfaces, 2019 Jan 09;11(1):1655-1664.
    PMID: 30561192 DOI: 10.1021/acsami.8b17758
    The ability of band offsets at multiferroic/metal and multiferroic/electrolyte interfaces in controlling charge transfer and thus altering the photoactivity performance has sparked significant attention in solar energy conversion applications. Here, we demonstrate that the band offsets of the two interfaces play the key role in determining charge transport direction in a downward self-polarized BFO film. Electrons tend to move to BFO/electrolyte interface for water reduction. Our experimental and first-principle calculations reveal that the presence of neodymium (Nd) dopants in BFO enhances the photoelectrochemical performance by reduction of the local electron-hole pair recombination sites and modulation of the band gap to improve the visible light absorption. This opens a promising route to the heterostructure design by modulating the band gap to promote efficient charge transfer.
    Matched MeSH terms: Recombination, Genetic
  16. Koko I, Song AA, Masarudin MJ, Abdul Rahim R
    BMC Biotechnol, 2019 11 27;19(1):82.
    PMID: 31775775 DOI: 10.1186/s12896-019-0575-x
    BACKGROUND: Site-specific integration system allows foreign DNA to be integrated into the specific site of the host genome, enabling stable expression of heterologous protein. In this study, integrative vectors for secretion and surface display of proteins were constructed based on a lactococcal phage TP901-1 integrating system.

    RESULTS: The constructed integration system comprises of a lactococcal promoter (PnisA or P170), phage attachment site (attP) from bacteriophage TP901-1, a signal peptide (USP45 or SPK1) for translocation of the target protein, and a PrtP344 anchor domain in the case of the integrative vectors for surface display. There were eight successfully constructed integrative vectors with each having a different combination of promoter and signal peptide; pS1, pS2, pS3 and pS4 for secretion, and pSD1, pSD2, pSD3 and pSD4 for surface display of desired protein. The integration of the vectors into the host genome was assisted by a helper vector harbouring the integrase gene. A nuclease gene was used as a reporter and was successfully integrated into the L. lactis genome and Nuc was secreted or displayed as expected. The signal peptide SPK1 was observed to be superior to USP45-LEISSTCDA fusion in the secretion of Nuc. As for the surface display integrative vector, all systems developed were comparable with the exception of the combination of P170 promoter with USP45 signal peptide which gave very low signals in whole cell ELISA.

    CONCLUSION: The engineered synthetic integrative vectors have the potential to be used for secretion or surface display of heterologous protein production in lactococcal expression system for research or industrial purposes, especially in live vaccine delivery.

    Matched MeSH terms: Recombination, Genetic*
  17. Lokman MQ, Shafie S, Shaban S, Ahmad F, Jaafar H, Mohd Rosnan R, et al.
    Materials (Basel), 2019 Jun 30;12(13).
    PMID: 31262020 DOI: 10.3390/ma12132111
    This study investigated the different thicknesses of TiO2 photoanode films and the effect of surface plasmon resonance (SPR) of Ag-TiO2 nanocomposites on the current-voltage (I-V) performance of dye-sensitized solar cells (DSSC). The TiO2 layer was deposited using the doctor blade technique and the thickness of the TiO2 films was controlled by using a different number of Scotch tape layers. The silver nanoparticles (AgNP) were synthesised using a chemical reduction method and the concentration of sodium citrate as a reducing agent was varied from 4 to 12 mM to study the effect of citrate ion on the size of the nanoparticles. Ag-TiO2 nanopowder was prepared by adding pure anatase TiO2 powder into AgNP colloidal solution. The mixture was left to dry for 24 h to obtain Ag-TiO2 powder for paste preparation. The three-layer Scotch tape, with thickness of 14.38 µm, achieved a high efficiency of 4.14%. This results showed that three layers was the optimal thickness to improve dye loading and to reduce the charge recombination rate. As for the Ag-TiO2 nanocomposites, 10 mM of AgNP, with a mean diameter of 65.23 nm and high efficiency of 6.92%, proved that SPR can enhance the absorption capability of dye and improve the photon-to-electron generation.
    Matched MeSH terms: Recombination, Genetic
  18. Lau KA, Wang B, Miranda-Saksena M, Boadle R, Kamarulzaman A, Ng KP, et al.
    Curr. HIV Res., 2010 Apr;8(3):259-71.
    PMID: 20214658
    In Malaysia, co-circulation of CRF01_AE and subtype B has resulted in the emergence of the second generation derivative; CRF33_01B in approximately 20% of its HIV-1 infected individuals. Our objective was to identify possible biological advantages that CRF33_01B possesses over its progenitors. Biological and molecular comparisons of CRF33_01B against its parental subtypes clearly show that CRF33_01B replicated better in activated whole peripheral blood mononuclear cells (PBMCs) and CD4+ T-lymphocytes, but not monocyte-derived macrophages (MDMs). Also, its acquired fitness was greater than CRF01_AE but not subtype B. Moreover, CRF33_01B has higher rate of apoptotic cell death and syncytia induction compared to subtype B. These adaptive and survival abilities could have been acquired by CRF33_01B due to the incorporation of subtype B fragments into the gag-RT region of its full-length genome. Our studies confirm the previously held belief that HIV-1 strains may harbor enhanced biological fitness upon recombination. We therefore estimate a possible gradual replacement of the current predominance of CRF01_AE, as well as wider dissemination of CRF33_01B, together with the identification of other new CRF01_AE/B inter-subtype recombinants in Malaysia.
    Matched MeSH terms: Recombination, Genetic
  19. Sirimahachai R, Harome H, Wongnawa S
    Sains Malaysiana, 2017;46:1393-1399.
    AgCl/BiYO3
    composite was successfully synthesized via the aqueous precipitation method followed by calcination. The
    varied amount of AgCl (10, 20 and 30%) was mixed into BiYO3
    via sonochemical-assisted method. The structures and
    morphologies of the as-prepared AgCl/BiYO3
    composite were characterized by x-ray diffraction (XRD), scanning electron
    microscopy (SEM) and UV-vis diffused reflectance spectroscopy (UV-vis DRS). The optical absorption spectrum of AgCl/
    BiYO3
    composite showed strong absorption in visible region. The photocatalytic activity of AgCl/BiYO3
    composite was
    evaluated by the photodegradation of reactive orange16 (RO16), which was selected to represent the dye pollutants,
    under UV and visible light irradiation. The results indicated that 20% AgCl/BiYO3 photocatalyst was the most capable
    photocatalyst in this series in the degradation of RO16 under both UV and visible light illumination within 1 h. Moreover,
    the mechanism of photocatalytic degradation of AgCl/BiYO3
    was elucidated using three types of free radical scavengers.
    The significant enhancement was attributed to the formation of AgCl/BiYO3
    heterojunction resulting in the low electronhole
    pair recombination rate.
    Matched MeSH terms: Recombination, Genetic
  20. Cheong HT, Chow WZ, Takebe Y, Chook JB, Chan KG, Al-Darraji HA, et al.
    PLoS One, 2015;10(7):e0133883.
    PMID: 26196131 DOI: 10.1371/journal.pone.0133883
    In many parts of Southeast Asia, the HIV-1 epidemic has been driven by the sharing of needles and equipment among intravenous drug users (IDUs). Over the last few decades, many studies have proven time and again that the diversity of HIV-1 epidemics can often be linked to the route of infection transmission. That said, the diversity and complexity of HIV-1 molecular epidemics in the region have been increasing at an alarming rate, due in part to the high tendency of the viral RNA to recombine. This scenario was exemplified by the discovery of numerous circulating recombinant forms (CRFs), especially in Thailand and Malaysia. In this study, we characterized a novel CRF designated CRF74_01B, which was identified in six epidemiologically unlinked IDUs in Kuala Lumpur, Malaysia. The near-full length genomes were composed of CRF01_AE and subtype B', with eight breakpoints dispersed in the gag-pol and nef regions. Remarkably, this CRF shared four and two recombination hotspots with the previously described CRF33_01B and the less prevalent CRF53_01B, respectively. Genealogy-based Bayesian phylogenetic analysis of CRF74_01B genomic regions showed that it is closely related to both CRF33_01B and CRF53_01B. This observation suggests that CRF74_01B was probably a direct descendent from specific lineages of CRF33_01B, CRF53_01B and subtype B' that could have emerged in the mid-1990s. Additionally, it illustrated the active recombination processes between prevalent HIV-1 subtypes and recombinants in Malaysia. In summary, we report a novel HIV-1 genotype designated CRF74_01B among IDUs in Kuala Lumpur, Malaysia. The characterization of the novel CRF74_01B is of considerable significance towards the understanding of the genetic diversity and population dynamics of HIV-1 circulating in the region.
    Matched MeSH terms: Recombination, Genetic*
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