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The cloning of Ty1-copia-like retrotransposons from 10 varieties of banana (Musa Sp.)

Teo CH, Tan SH, Othman YR, Schwarzacher T

J. Biochem. Mol. Biol. Biophys., 2002 Jun;6(3):193-201.
PMID: 12186754

Ty1-copia-like retrotransposons have been identified and investigated in several plant species. Here, the internal region of the reverse transcriptase (RT) gene of Ty1-copia-like retrotransposons was amplified by PCR from total genomic DNA of 10 varieties of banana. Two to four clones from each variety were sequenced. Extreme heterogeneity in the sequences of Ty1-copia-like retrotransposons from all the varieties was revealed following sequence analysis of the reverse transcriptase (RT) fragments. The size of the individual RT gene fragments varied between 213 and 309 bp. Southern blots of genomic DNA digested from Musa acuminata and other banana varieties probed with W8 clone from M. acuminata and A4 clone from Pisang Abu Nipah showed similar strong, multiple restriction fragments together with other faint hybridization band patterns with variable intensities indicating the presence of many copies of the Ty1-copia-like retrotransposons in the genomes. There was no correlation between retroelement sequence and the banana species (with A or B genomes) from which it arose, suggesting that the probes are not useful for tracking genomes through breeding populations.
Fulltext Fibroblast growth factor receptor 4 (FGFR4) and fibroblast growth factor 19 (FGF19) autocrine enhance breast cancer cells survival

Tiong KH, Tan BS, Choo HL, Chung FF, Hii LW, Tan SH, et al.

Oncotarget, 2016 Sep 06;7(36):57633-57650.
PMID: 27192118 DOI: 10.18632/oncotarget.9328

Basal-like breast cancer is an aggressive tumor subtype with poor prognosis. The discovery of underlying mechanisms mediating tumor cell survival, and the development of novel agents to target these pathways, is a priority for patients with basal-like breast cancer. From a functional screen to identify key drivers of basal-like breast cancer cell growth, we identified fibroblast growth factor receptor 4 (FGFR4) as a potential mediator of cell survival. We found that FGFR4 mediates cancer cell survival predominantly via activation of PI3K/AKT. Importantly, a subset of basal-like breast cancer cells also secrete fibroblast growth factor 19 (FGF19), a canonical ligand specific for FGFR4. siRNA-mediated silencing of FGF19 or neutralization of extracellular FGF19 by anti-FGF19 antibody (1A6) decreases AKT phosphorylation, suppresses cancer cell growth and enhances doxorubicin sensitivity only in the FGFR4+/FGF19+ breast cancer cells. Consistently, FGFR4/FGF19 co-expression was also observed in 82 out of 287 (28.6%) primary breast tumors, and their expression is strongly associated with AKT phosphorylation, Ki-67 staining, higher tumor stage and basal-like phenotype. In summary, our results demonstrated the presence of an FGFR4/FGF19 autocrine signaling that mediates the survival of a subset of basal-like breast cancer cells and suggest that inactivation of this autocrine loop may potentially serve as a novel therapeutic intervention for future treatment of breast cancers.
Bud development, flower phenology and life history of holoparasitic Rafflesia cantleyi

Wee SL, Tan SB, Tan SH, Lee BKB

J Plant Res, 2024 Feb 14.
PMID: 38353931 DOI: 10.1007/s10265-024-01522-7

Despite being the world's largest single-flower, Rafflesia's biology and life history are still poorly understood due to its cryptic growth strategy on Tetrastigma vines. Previous studies have been mostly short-term, contrary to Rafflesia's long development period before blooming. Bud development and flower phenology of R. cantleyi was studied in a dipterocarp forest in Lata Jarum, Peninsular Malaysia. Seven populations, consisting of 247 buds, were monitored fortnightly for 65 months in two discrete studies between 2009 and 2018. The bud size distribution of R. cantleyi is dynamic, progressively changing from small flower buds to larger buds before flowering. Buds 15.0 cm across demonstrated accelerated growth. The bud growth profiles of the same site clustered distinctively regardless of sex with successful blooming rate that varied greatly between sites, prompting speculation about their relatedness to the sites' physical attributes. We reported the first female-dominated population in Rafflesia's life history. Rafflesia cantleyi's blooming rate at Lata Jarum is moderate to high, with non-seasonal flowering phenology as evident by the lack of synchronisation and consistency between flowering and local rainfall patterns. Based on the field data of the present study and the published information of other Rafflesia species, R. cantleyi's life cycle was estimated between 4.0 and 5.3 years. Our findings further explain Rafflesia's biology and life history and highlight the gap in knowledge of the natural habitats on the endoparasite's growth and fate potentially for future conservation and study.
Fulltext Sea cucumbers of the genus Stichopus Brandt, 1835 (Holothuroidea, Stichopodidae) in Straits of Malacca with description of a new species

Woo SP, Yasin Z, Tan SH, Kajihara H, Fujita T

Zookeys, 2015.
PMID: 26798290 DOI: 10.3897/zookeys.545.6415

Five sea cucumber species including one new species of the genus Stichopus are reported from the shallow coral reefs of Straits of Malacca. The new species Stichopus fusiformiossa has unusual fusiform spicules in the tentacles, which are not found in the other species of the genus. Pseudo-tables and large perforated plates are newly recorded for Stichopus hermanni Semper, 1868 and Stichopus vastus Sluiter, 1887, respectively.
Fulltext The Wound Healing Potential of Lignosus rhinocerus and Other Ethno-myco Wound Healing Agents

Yap HY, Ariffeen Rosli MF, Tan SH, Kong BH, Fung SY

Mycobiology, 2023;51(1):1-15.
PMID: 36846625 DOI: 10.1080/12298093.2022.2164641

Wound care has become increasingly important over the years. Various synthetic products for wound care treatment have been reported to cause toxic side effects and therefore natural products are in significant demand as they have minimal side effects. The presence of bioactive compounds in medicinal mushrooms contributes to various biological activities which assist in the early inflammatory phase, keratinocyte proliferation, and its migration enhancement which are pertinent to wound rehabilitation. Lignosus rhinocerus (tiger milk mushroom) can reduce the inflammation phase in wound healing by fighting off bacterial infection and modulating pro-inflammatory cytokines expression in the early stage to avoid prolonged inflammation and tissue damage. The antibacterial, immunomodulating, and anti-inflammatory activities exhibited by most macrofungi play a key role in enhancing wound healing. Several antibacterial and antifungal compounds sourced from traditional botanicals/products may prevent further complications and reoccurrence of injury to a wounded site. Scientific studies are actively underway to ascertain the potential use of macrofungi as a wound healing agent.
Fulltext Decoding Antioxidant and Antibacterial Potentials of Malaysian Green Seaweeds: Caulerpa racemosa and Caulerpa lentillifera

Yap WF, Tay V, Tan SH, Yow YY, Chew J

Antibiotics (Basel), 2019 Sep 17;8(3).
PMID: 31533237 DOI: 10.3390/antibiotics8030152

Seaweeds are gaining a considerable amount of attention for their antioxidant and antibacterial properties. Caulerpa racemosa and Caulerpa lentillifera, also known as 'sea grapes', are green seaweeds commonly found in different parts of the world, but the antioxidant and antibacterial potentials of Malaysian C. racemosa and C. lentillifera have not been thoroughly explored. In this study, crude extracts of the seaweeds were prepared using chloroform, methanol, and water. Total phenolic content (TPC) and total flavonoid content (TFC) were measured, followed by in vitro antioxidant activity determination using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Antibacterial activities of these extracts were tested against Methicillin-resistant Staphylococcus aureus (MRSA) and neuropathogenic Escherichia coli K1. Liquid chromatography-mass spectrometry (LCMS) analysis was then used to determine the possible compounds present in the extract with the most potent antioxidant and antibacterial activity. Results showed that C. racemosa chloroform extract had the highest TPC (13.41 ± 0.86 mg GAE/g), antioxidant effect (EC50 at 0.65 ± 0.03 mg/mL), and the strongest antibacterial effect (97.7 ± 0.30%) against MRSA. LCMS analysis proposed that the chloroform extracts of C. racemosa are mainly polyunsaturated and monounsaturated fatty acids, terpenes, and alkaloids. In conclusion, C. racemosa can be a great source of novel antioxidant and antibacterial agents, but isolation and purification of the bioactive compounds are needed to study their mechanism of action.
Fulltext Elderly's intention to use technologies: A systematic literature review

Yap YY, Tan SH, Choon SW

Heliyon, 2022 Jan;8(1):e08765.
PMID: 35128090 DOI: 10.1016/j.heliyon.2022.e08765

The population aging and an increased life expectancy are widely recognized social changes. Technologies are believed to improve the elderly's daily lives and maintain their health efficiently. Despite the advantage of adopting technologies, the elderly are slower to adopt new technologies compared to younger adults. This paper presents a Systematic Literature Review (SLR) to identify the different antecedents prevailing in the literature on elderly technology adoption. The SLR classifies and analyzes 26 relevant articles on elderly's technology adoption. Our findings revealed that quantitative approach and cross-sectional studies predominate in this field, building fundamentally upon the technology-driven theories. We identify seven categories of antecedents influencing elderly's use of technology, namely, technology, psychological, social, personal, cost, behavior, and environment antecedents. A conceptual framework for elderly's technology adoption and recommendations were presented. Particular attention is given to the need for in depth study for the antecedents, development of new measurement scales and investigation on the effectiveness of the proposed benefits after technology adoption.
Fulltext Online grocery shopping intention: Elderly's perspective in Malaysia

Yap YY, Tan SH, Tan SK, Choon SW

Heliyon, 2023 Oct;9(10):e20827.
PMID: 37916123 DOI: 10.1016/j.heliyon.2023.e20827

PURPOSE: This study investigates the factors associated with the elderly's intention to use OGS. Building on the Technology Acceptance Model, we propose several elderly-specific and functional-ageing constructs related to the perceived ease of use and usefulness of OGS.
METHODS: The questionnaire was distributed physically and digitally to non-OGS users aged above 60, living in the Klang Valley, Malaysia, using a non-probability sampling approach. A total of 302 data were analysed using PLS structural equation modelling.
RESULTS: The findings indicate that perceived ease of use, functional ability, life-course events, and digital literacy are associated with the elderly's perception of OGS's usefulness, while life-course events, digital literacy, technology anxiety, and facilitating conditions are associated with the perceived ease of use.
CONCLUSION: This study contributes to the OGS literature by addressing ageing complexities with OGS adoption among the elderly population, thereby offering insights for marketers and the government to tailor services and provide relevant support.
Fulltext Development of live attenuated Enterovirus 71 vaccine strains that confer protection against lethal challenge in mice

Yee PTI, Tan SH, Ong KC, Tan KO, Wong KT, Hassan SS, et al.

Sci Rep, 2019 03 18;9(1):4805.
PMID: 30886246 DOI: 10.1038/s41598-019-41285-z

Besides causing mild hand, foot and mouth infections, Enterovirus A71 (EV-A71) is associated with neurological complications and fatality. With concerns about rising EV-A71 virulence, there is an urgency for more effective vaccines. The live attenuated vaccine (LAV) is a more valuable vaccine as it can elicit both humoral and cellular immune responses. A miRNA-based vaccine strain (pIY) carrying let-7a and miR-124a target genes in the EV-A71 genome which has a partial deletion in the 5'NTR (∆11 bp) and G64R mutation (3Dp°l) was designed. The viral RNA copy number and viral titers of the pIY strain were significantly lower in SHSY-5Y cells that expressed both let-7a and miR-124a. Inhibition of the cognate miRNAs expressed in RD and SHSY-5Y cells demonstrated de-repression of viral mRNA translation. A previously constructed multiply mutated strain, MMS and the pIY vaccine strain were assessed in their ability to protect 4-week old mice from hind limb paralysis. The MMS showed higher amounts of IFN-γ ex vivo than the pIY vaccine strain. There was absence of EV-A71 antigen in the skeletal muscles and spinal cord micrographs of mice vaccinated with the MMS and pIY strains. The MMS and pIY strains are promising LAV candidates developed against severe EV-A71 infections.
Fulltext Molecular Detection of Legionella: Moving on From mip

Yong SF, Tan SH, Wee J, Tee JJ, Sansom FM, Newton HJ, et al.

Front Microbiol, 2010;1:123.
PMID: 21687766 DOI: 10.3389/fmicb.2010.00123

The detection of Legionella pneumophila in environmental and clinical samples is frequently performed by PCR amplification of the mip and/or 16S rRNA genes. Combined with DNA sequencing, these two genetic loci can be used to distinguish different species of Legionella and identify L. pneumophila. However, the recent Legionella genome sequences have opened up hundreds of possibilities for the development of new molecular targets for detection and diagnosis. Ongoing comparative genomics has the potential to fine tune the identification of Legionella species and serogroups by combining specific and general genetic targets. For example, the coincident detection of LPS biosynthesis genes and virulence genes may allow the differentiation of both pathogen and serogroup without the need for nucleotide sequencing. We tested this idea using data derived from a previous genomic subtractive hybridization we performed between L. pneumophila serogroup 1 and L. micdadei. Although not yet formally tested, these targets serve as an example of how comparative genomics has the potential to improve the scope and accuracy of Legionella molecular detection if embraced by laboratories undertaking Legionella surveillance.
Fulltext Photophysical and Electroluminescence Characteristics of Polyfluorene Derivatives with Triphenylamine

Zhang Q, Wang PI, Ong GL, Tan SH, Tan ZW, Hii YH, et al.

Polymers (Basel), 2019 May 09;11(5).
PMID: 31075895 DOI: 10.3390/polym11050840

In this work, polymers of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-triphenylamine] with side chains containing: pyrene (C1), diphenyl (C2), naphthalene (C3), and isopropyl (C6) structures were synthesized via a Suzuki coupling reaction. The structures were verified using NMR and cyclic voltammetry measurements provide the HOMO and LUMO of the polymers. The polymer with pyrene (C1) and naphthalene (C3) produced photoluminescence in the green while the polymer with the side chain containing diphenyl (C2) and isopropyl (C6) produce dual emission peaks of blue-green photoluminescence (PL). In order to examine the electroluminescence properties of the polymers, the solutions were spin-coated onto patterned ITO anode, dried, and subsequently coated with an Al cathode layer to form pristine single layer polymer LEDs. The results are compared to a standard PFO sample. The electroluminescence spectra resemble the PL spectra for C1 and C3. The devices of C2, C3, and C6 exhibit voltage-dependent EL. An additional red emission peak was detected for C2 and C6, resulting in spectra with peaks at 435 nm, 490 nm, and 625 nm. The effects of the side chains on the spectral characteristics of the polymer are discussed.
Fulltext Plasma Ceramides as Prognostic Biomarkers and Their Arterial and Myocardial Tissue Correlates in Acute Myocardial Infarction

de Carvalho LP, Tan SH, Ow GS, Tang Z, Ching J, Kovalik JP, et al.

JACC Basic Transl Sci, 2018 Apr;3(2):163-175.
PMID: 30062203 DOI: 10.1016/j.jacbts.2017.12.005

We identified a plasma signature of 11 C14 to C26 ceramides and 1 C16 dihydroceramide predictive of major adverse cardiovascular events in patients with acute myocardial infarction (AMI). Among patients undergoing coronary artery bypass surgery, those with recent AMI, compared with those without recent AMI, showed a significant increase in 5 of the signature's 12 ceramides in plasma but not simultaneously-biopsied aortic tissue. In contrast, a rat AMI model, compared with sham control, showed a significant increase in myocardial concentrations of all 12 ceramides and up-regulation of 3 ceramide-producing enzymes, suggesting ischemic myocardium as a possible source of this ceramide signature.

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