Huang Liqun
Email Address
nmihlq@nus.edu.sg
9 results
Publication Search Results
Now showing 1 - 9 of 9
Publication The myeloid features of BXH2 leukemias may result from the lack of one copy of the repetitive sequence in the long terminal repeat viral enhancer [1](2007) Huang, L.; Osato, M.; Ito, Y.; Yanagida, M.; Yamashita, N.; MEDICINE; NATIONAL UNIVERSITY MEDICAL INSTITUTESPublication Proteomic analysis of human tears: Defensin expression after ocular surface surgery(2004) Zhou, L.; Beuerman, R.W.; Tan, D.; Huang, L.Q.; Li, S.F.Y.; Grigg, M.E.; Chew, F.T.; Ang, L.; Stern, M.E.; MEDICINE; NATIONAL UNIVERSITY MEDICAL INSTITUTES; CHEMISTRY; BIOLOGICAL SCIENCES; OPHTHALMOLOGYPublication Proteomic analysis of rabbit tear fluid: Defensin levels after an experimental corneal wound are correlated to wound closure(2007-09) Zhou, L.; Beuerman, R.W.; Huang, L.; Barathi, A.; Yong, H.F.; Li, S.F.Y.; Fook, T.C.; Tan, D.; NATIONAL UNIVERSITY MEDICAL INSTITUTES; CHEMISTRY; BIOLOGICAL SCIENCESThe cornea is the major refracting optical element of the eye and therefore critical for forming a retinal image. The exposed surface of the eye is protected from pathogens by the innate immune system whose components include defensins, naturally occurring peptides with antimicrobial properties, and the physical barrier formed by the outer epithelial layer of the cornea. The proteomic approach has revealed that tear levels of defensins are correlated with the course of healing of an experimental corneal wound. Tears were collected from New Zealand White rabbits prior to (day 0) and daily for 5 days (days 1-5) following a standard unilateral 6 mm diameter corneal epithelial abrasion. Tear protein profiles obtained from wounded and contra-lateral control eyes were compared using SELDI ProteinChip technology. Peptides and proteins of interest were purified by RP-HPLC and characterized by nanoESI-MS/MS. Mass spectra of tears on post-wound day 1, revealed 13 peaks whose level decreased and five that increased. During wound healing the tear protein profile correlated with wound closure. An important finding was that the levels of rabbit defensins (NP-1 and NP-2), which were elevated after wounding returned to normal levels by the time the corneal abrasion healed. Relative quantification of NP-2 in tear fluid prior to (day 0) and after corneal wounding (days 1-3) was determined using iTRAQ technology. A corneal wound eliminates the barrier function of innate immunity and puts the cornea at risk from microbial attack until the epithelial cells restore the surface barrier. The increased availability of defensins in the tears during healing suggests that these peptides could protect the cornea from microbial attack during a period of increased vulnerability. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.Publication Haploinsufficiency of Runx1/AML1 promotes myeloid features and leukaemogenesis in BXH2 mice(2005) Ito, Y.; Yamashita, N.; Osato, M.; Yanagida, M.; Shigesada, K.; Huang, L.; Kogan, S.C.; Iwasaki, M.; Nakamura, T.; Asou, N.; MEDICINE; NATIONAL UNIVERSITY MEDICAL INSTITUTESPublication Detection of two orchid viruses using quartz crystal microbalance-based DNA biosensors(2002) Eun, A.J.-C.; Huang, L.; Chew, F.-T.; Li, S.F.-Y.; Wong, S.-M.; CHEMISTRY; BIOLOGICAL SCIENCESWe have developed a piezoelectric DNA-sensor based on DNA-RNA hybridization for the detection of two orchid viruses, Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV). Specific oligonucleotide probes modified with a mercaptohexyl group at the 5′-phosphate end were directly immobilized onto 10-MHz AT-cut quartz crystal microbalance (QCM). QCMs coated with such oligonucleotide probes were exposed to test solutions containing viral RNA for hybridization. Various experimental conditions evaluated were (i) DNA probe coating concentration, (ii) sensitivity and specificity of the probes at different hybridization temperatures, and (iii) effects of incubation temperature on the hybridization time. The specific nucleotide probe-coated QCM-based DNA sensors were able to detect both CymMV and ORSV in quantities as low as approximately 1 ng in purified RNA preparations and 10 ng in the crude sap of infected orchids. This is the first application of a DNA biosensor for the detection of plant viruses.Publication Increased dosage of Runx1/AML1 acts as a positive modulator of myeloid leukemogenesis in BXH2 mice(2005) Yanagida, M.; Osato, M.; Yamashita, N.; Jacob, B.; Cao, X.; Ito, Y.; Liqun, H.; Wu, F.; Shigesada, K.; Nakamura, T.; Yokomizo, T.; Takahashi, S.; Yamamoto, M.; MEDICINE; NATIONAL UNIVERSITY MEDICAL INSTITUTESPublication Protein microarrays on ITO surfaces by a direct covalent attachment scheme(2002-08-06) Ng, H.T.; Fang, A.; Huang, L.; Li, S.F.Y.; CHEMISTRYWe describe the use of an indium tin oxide (ITO) thin film on a solid support serving as an effective generic immobilization platform to achieve one-step direct covalent attachment of arrayed proteins with good reproducibility and uniformity, Potential functional analyses on these surfaces involving protein-protein and protein-ligand interactions have been demonstrated. We also show that the approach can be adapted, via a photolithography-derived microwell route, to produce high-density protein microarrays which typically could accommodate a significantly higher density while occupying a comparatively smaller footprint than that achievable using currently existing high-precision robotic microarrayer systems, suggesting its potential applications in simultaneous parallel biological assays.Publication Detection of two orchid viruses using quartz crystal microbalance (QCM) immunosensors(2002) Eun, A.J.-C.; Huang, L.; Chew, F.-T.; Li, S.F.-Y.; Wong, S.-M.; CHEMISTRY; BIOLOGICAL SCIENCESQuartz crystal microbalance (QCM) immunosensors are based on the principle that adsorption of substances on the surface of a quartz crystal changes its resonance oscillation frequency. A QCM immunosensor was developed for the detection of both cymbidium mosaic potexvirus (CymMV) and odontoglossum ringspot tobamovirus (ORSV) by pre-coating the QCMs with virus-specific antibodies. Upon binding of virions in either purified form or crude sap of infected orchids with the immobilised virus antibodies, the increase in mass at the QCM surface resulted in a reduction in the frequency of resonance oscillation in a manner dependent upon the amount of virus bound. The QCM was able to detect as low as 1 ng each of the two orchid viruses. This detection sensitivity is comparable to enzyme linked immunosorbent assay (ELISA) but the assay is faster. This immunoassay was shown to be specific, sensitive, rapid and economical, thus providing a viable alternative to virus detection methods. This is the first report using QCM immunosensors to detect plant viruses. © 2002 Elsevier Science B.V. All rights reserved.Publication Microgravimetric DNA sensor based on quartz crystal microbalance: Comparison of oligonucleotide immobilization methods and the application in genetic diagnosis(2001) Zhou, X.C.; Huang, L.Q.; Li, S.F.Y.; ANATOMY; CHEMISTRYWe report on the study of immobilization DNA probes onto quartz crystal oscillators by self-assembly technique to form variety types of mono- and multi-layered sensing films towards the realization of DNA diagnostic devices. A 18-mer DNA probe complementary to the site of genetic β-thalassaemia mutations was immobilized on the electrodes of QCM by covalent bonding or electrostatic adsorption on polyelectrolyte films to form mono- or multi-layered sensing films by self-assembled process. Hybridization was induced by exposure of the QCMs immobilized with DNA probe to a test solution containing the target nucleic acid sequences. The kinetics of DNA probe immobilization and hybridization with the fabricated DNA sensors were studied via in-situ frequency changes. The characteristics of QCM sensors containing mono- or multi-layered DNA probe constructed by direct chemical bonding, avidin-biotin interaction or electrostatic adsorption on polyelectrolyte films were compared. Results indicated that the DNA sensing films fabricated by immobilization of biotinylated DNA probe to avidin provide fast sensor response and high hybridization efficiencies. The effects of ionic strength of the buffer solution and the concentration of target nucleic acid used in hybridization were also studied. The fabricated DNA biosensor was used to detect a set of real samples. We conclude that the microgravimetric DNA sensor with its direct detection of amplified products provide a rapid, low cost and convenient diagnostic method for genetic disease. © 2001 Elsevier Science B.V.