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Izulla P, Wagai JN, Akelo V, Ombeva A, Okeri E, Onyango D, Omore R, Fuller S, Khagayi S, Were J, Anderson SA, Wong HL, Tippett Barr BA. Vaccine safety surveillance in Kenya using GAIA standards: A feasibility assessment of existing national and subnational research and program systems. Vaccine 2023; 41:5722-5729. [PMID: 37550143 DOI: 10.1016/j.vaccine.2023.07.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 04/17/2023] [Accepted: 07/26/2023] [Indexed: 08/09/2023]
Abstract
BACKGROUND Active surveillance systems for monitoring vaccine safety among pregnant women address some of the limitations of a current passive surveillance approach utilized in low- and middle-income countries (LMIC). However, few active surveillance systems in LMIC exist. Our study assessed the feasibility of utilizing three existing data collection systems in Kenya for active surveillance of maternal immunization and to assess the applicability of Global Alignment of Immunization Safety Assessment in pregnancy (GAIA) case definitions that were initially developed for clinical trials within these systems. METHODS We assessed applicability of GAIA case definition for maternal Tetanus Toxoid exposure, stillbirth, low birth weight, small for gestational age, Neonatal Invasive Blood Stream Infection (NIBSI), prematurity and neonatal death in two routine web-based health information systems (Kenya EMR and DHIS-2), and a web-based population-based pregnancy research platform (ANCOV1) in Kenya. RESULTS All three HIS were capable of reporting selected outcomes to varying degrees of GAIA certainty. The ANCOV platform was the most robust in collecting and collating clinical data for effective maternal pharmacovigilance. The utilization of facility- and district-aggregated data limits the usefulness of DHIS-2 in pharmacovigilance as currently operationalized. While the Kenya EMR contained individual level data and meets the key considerations for effective pharmacovigilance, it was used primarily for HIV care and treatment records in a small proportion of health facilities and would require additional resources to expand to all antenatal care facilities and to link maternal and infant records. DISCUSSION Population-based research studies may offer a responsive short-term option for implementing maternal vaccine pharmacovigilance in LMICs. However, the foundation exists for long-term capacity building within the national health electronic data systems to provide this critical service as well as ensure participation of the country in international studies on maternal vaccine safety.
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Affiliation(s)
- P Izulla
- Adroitz Consultants, Nairobi, Kenya.
| | | | - V Akelo
- US Centers for Disease Control and Prevention, Kisumu, Kenya
| | - A Ombeva
- Adroitz Consultants, Nairobi, Kenya
| | - E Okeri
- Adroitz Consultants, Nairobi, Kenya
| | - D Onyango
- Kisumu County Department of Health, Kisumu, Kenya
| | - R Omore
- Kenya Medical Research Institute Center for Global Health Research, Kisumu, Kenya
| | - S Fuller
- US Centers for Disease Control and Prevention, Kisumu, Kenya
| | - S Khagayi
- Kenya Medical Research Institute Center for Global Health Research, Kisumu, Kenya
| | - J Were
- Kenya Medical Research Institute Center for Global Health Research, Kisumu, Kenya
| | - S A Anderson
- US Food and Drug Administration, Silver Spring, USA
| | - H L Wong
- US Food and Drug Administration, Silver Spring, USA
| | - B A Tippett Barr
- US Centers for Disease Control and Prevention, Kisumu, Kenya; Nyanja Health Research Institute, Salima, Malawi
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Toh WK, Teo YL, Tor XY, Loh PC, Wong HL. Development of constitutive and IPTG-inducible integron promoter-based expression systems for Escherichia coli and Agrobacterium tumefaciens. 3 Biotech 2023; 13:91. [PMID: 36825259 PMCID: PMC9941393 DOI: 10.1007/s13205-023-03507-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 01/31/2023] [Indexed: 02/23/2023] Open
Abstract
Broad host range (BHR) expression vector is a vital tool in molecular biology research and application. Currently, most of the plasmid vectors used in Agrobacterium spp. are binary vectors that are designed for plant transformation, and very few are designed for expressing transgenes in Agrobacterium spp. Class 1 integrons are common genetic elements that allow for the efficient capture and expression of antibiotic resistance genes, especially in Gram-negative bacteria. One of its compound promoters, PcS + P2, was used in this study and has been reported to be the strongest class 1 integron constitutive promoter; it is referred to as "integron promoter" (P int) henceforth. Herein, we created two versions of isopropyl-d-thiogalactopyranoside (IPTG)-inducible promoters by substituting and/or inserting lacO sequence(s) into P int. These inducible promoters, which possess different degrees of stringency and inducibility, were used to construct two broad host range expression vectors (pWK102 and pWK103) based on the versatile pGREEN system. This allows them to be stably maintained and replicated in both Escherichia coli and Agrobacterium tumefaciens. Functional validation of these vectors was performed by the expression of the reporter gene, superfolder green fluorescent protein (sfGFP), which was cloned downstream of these promoters. Due to the strong induction and tunable expression of a transgene located downstream to the inducible integron promoter, these vectors may be useful for heterologous gene expression in both E. coli and A. tumefaciens, thus facilitating recombinant protein production and genetic studies in Gram-negative bacteria. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03507-0.
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Affiliation(s)
- Wai Keat Toh
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak Malaysia
| | - Yuh Leng Teo
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak Malaysia
| | - Xin Yen Tor
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak Malaysia
| | - Pek Chin Loh
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak Malaysia
| | - Hann Ling Wong
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak Malaysia
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Wong YL, Cheng CPW, Wong CSM, Wong SN, Wong HL, Tse S, Wong GHY, Chan WC. Cognitive Stimulation for Persons with Dementia: a Systematic Review and Meta-Analysis. East Asian Arch Psychiatry 2021; 31:55-66. [PMID: 34588315 DOI: 10.12809/eaap2102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE We aim to provide an up-to-date systematic review and meta-analysis of the effects of cognitive stimulation (CS) on cognition, depressive symptoms, and quality of life in persons with dementia. Factors affecting the treatment effect were examined. METHODS A literature search was performed on databases of MEDLINE, EMBASE, PsycINFO, CINAHL Plus, and Cochrane Library up to 7 March 2019. Only randomised controlled trials investigating the effects of CS in persons with dementia were included. The outcome measures were cognitive function, depressive symptoms, and quality of life. RESULTS 20 randomised controlled trials with a total of 1251 participants (intervention group: 674; control group: 577) were included for meta-analysis. Most participants had mild to moderate dementia. CS had a significant positive small-to-moderate effect on cognition (Hedges's g = 0.313, p < 0.001). Heterogeneity of CS was low to moderate (Q=30.5854, df=19, p < 0.05, I2 = 37.877%). Inconclusive results were found for depressive symptoms and quality of life. CONCLUSION CS has a significant positive effect on cognitive function, but its effect on depressive symptoms and quality of life was inconclusive. Future studies with more robust methodology establishing evidence of its efficacy are required.
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Affiliation(s)
- Y L Wong
- Department of Psychiatry, Queen Mary Hospital, Hong Kong
| | - C P W Cheng
- Department of Psychiatry, Queen Mary Hospital, Hong Kong
| | - C S M Wong
- Department of Psychiatry, Queen Mary Hospital, Hong Kong
| | - S N Wong
- Department of Psychiatry, Queen Mary Hospital, Hong Kong
| | - H L Wong
- Department of Psychology, The University of Hong Kong, Hong Kong
| | - S Tse
- Department of Psychiatry, Queen Mary Hospital, Hong Kong
| | - G H Y Wong
- Department of Social Work and Social Administration, The University of Hong Kong, Hong Kong
| | - W C Chan
- Department of Psychiatry, Queen Mary Hospital, Hong Kong
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Lam SY, Wong HL, Ling TSC, Hui HF, Sasaki S, Ho YL, Leung OC, Siu JCW, Tan CB. Patient Satisfaction with a Multidisciplinary Team Approach to Uterine Artery Embolisation: Preliminary Results. Hong Kong Journal of Radiology 2021. [DOI: 10.12809/hkjr2117031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- SY Lam
- Department of Radiology, Tuen Mun Hospital, Hong Kong
| | - HL Wong
- Department of Radiology, Tuen Mun Hospital, Hong Kong
| | - TSC Ling
- Department of Obstetrics and Gynaecology, Tuen Mun Hospital, Hong Kong
| | - HF Hui
- Department of Obstetrics and Gynaecology, Tuen Mun Hospital, Hong Kong
| | - S Sasaki
- Department of Anaesthesiology and Intensive Care, Tuen Mun Hospital, Hong Kong
| | - YL Ho
- Department of Anaesthesiology and Intensive Care, Tuen Mun Hospital, Hong Kong
| | - OC Leung
- Department of Radiology, Tuen Mun Hospital, Hong Kong
| | - JCW Siu
- Department of Radiology, Tuen Mun Hospital, Hong Kong
| | - CB Tan
- Department of Radiology, Tuen Mun Hospital, Hong Kong
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Jalali A, Gard G, Banks S, Dunn C, Wong HL, Wong R, Lee M, Gately L, Loft M, Shapiro JD, Kosmider S, Tie J, Ananda S, Yeung JM, Jennens R, Lee B, McKendrick J, Lim L, Khattak A, Gibbs P. Initial experience of TAS-102 chemotherapy in Australian patients with Chemo-refractory metastatic colorectal cancer. Curr Probl Cancer 2021; 46:100793. [PMID: 34565601 DOI: 10.1016/j.currproblcancer.2021.100793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/09/2021] [Accepted: 08/20/2021] [Indexed: 11/24/2022]
Abstract
For patients with refractory metastatic colorectal cancer (mCRC) treatment with Trifluridine/Tipiracil, also known as TAS-102, improves overall survival. This study aims to investigate the efficacy and safety of TAS-102 in a real-world population from Victoria, Australia. A retrospective analysis of prospectively collected data from the Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) registry was undertaken. The characteristics and outcomes of patients receiving TAS-102 were assessed and compared to those enrolled in the registration study (RECOURSE). Across 13 sites, 107 patients were treated with TAS-102. The median age was 60 years (range: 31-83), compared to 63 for RECOURSE. Comparing registry TAS-102-treated and RECOURSE patients, 75% vs 100% were ECOG performance status 0-1, 74% vs 79% had initiated treatment more than 18 months from diagnosis of metastatic disease and 36% vs 49% were RAS wild-type. Median time on treatment was 10.4 weeks (range: 1.7-32). Median progression-free survival (PFS) was 3.3 months compared to 2 months in RECOURSE, while median overall survival was the same at 7.1 months. Two patients (2.3%) had febrile neutropenia and there were no treatment-related deaths, where TAS-102 dose at treatment initiation was at clinician discretion.TRACC registry patients treated with TAS-102 were younger than those from the RECOURSE trial, with similar overall survival observed. Less strict application of RECIST criteria and less frequent imaging may have contributed to an apparently longer PFS.
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Affiliation(s)
- A Jalali
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia; Department of Medical Oncology, Western Health, VIC, Australia; Department of Medical Oncology, Latrobe Regional Hospital, VIC, Australia.
| | - G Gard
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia
| | - S Banks
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia
| | - C Dunn
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia
| | - H L Wong
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia; Department of Medical Oncology, Peter MacCallum Cancer Centre, VIC, Australia
| | - R Wong
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia; Department of Medical Oncology, Eastern Health, VIC, Australia; Eastern Health Clinical School, Monash University, VIC, Australia
| | - M Lee
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia; Department of Medical Oncology, Western Health, VIC, Australia; Department of Medical Oncology, Eastern Health, VIC, Australia; Eastern Health Clinical School, Monash University, VIC, Australia
| | - L Gately
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia
| | - M Loft
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia
| | - J D Shapiro
- Department of Medical Oncology, Cabrini Hospital, VIC, Australia
| | - S Kosmider
- Department of Medical Oncology, Western Health, VIC, Australia
| | - J Tie
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia; Department of Medical Oncology, Western Health, VIC, Australia; Department of Medical Oncology, Peter MacCallum Cancer Centre, VIC, Australia
| | - S Ananda
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia; Department of Medical Oncology, Western Health, VIC, Australia; Department of Medical Oncology, Peter MacCallum Cancer Centre, VIC, Australia; Department of Medical Oncology, Epworth Health, VIC, Australia
| | - J M Yeung
- Department of Surgery, Western Health, University of Melbourne, VIC, Australia; Western Health Chronic Disease Alliance, Western Health, VIC, Australia
| | - R Jennens
- Department of Medical Oncology, Epworth Health, VIC, Australia
| | - B Lee
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia; Department of Medical Oncology, Peter MacCallum Cancer Centre, VIC, Australia; Department of Medical Oncology, Northern Health, VIC, Australia
| | - J McKendrick
- Department of Medical Oncology, Eastern Health, VIC, Australia; Department of Medical Oncology, Epworth Health, VIC, Australia
| | - L Lim
- Department of Medical Oncology, Eastern Health, VIC, Australia
| | - A Khattak
- Department of Medical Oncology, Fiona Stanley Hospital, WA, Australia
| | - P Gibbs
- Division of Personalised Oncology, Walter and Eliza Hall Institute of Medical Research, VIC, Australia; Department of Medical Oncology, Western Health, VIC, Australia
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Shih VWY, Chan WC, Tai OK, Wong HL, Cheng CPW, Wong CSM. Mindfulness-Based Cognitive Therapy for Late-Life Depression: a Randomised Controlled Trial. East Asian Arch Psychiatry 2021; 31:27-35. [PMID: 34987115 DOI: 10.12809/eaap2075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
BACKGROUND Rumination and overgeneral autobiographical memory are dysfunctional cognitions commonly found in older adults with depression. The theoretical underpinnings of mindfulness-based cognitive therapy (MBCT) address the ruminative tendencies and the non-specific retrieval of autobiographical memories. This study aims to examine the efficacy and cognitive mechanisms of MBCT in older adults with active depressive symptoms. METHODS 57 older adults (mean age, 70 years) with normal cognition and mild to moderate depressive symptoms were randomly allocated to either the MBCT group or the active control group for 8 weeks. The MBCT group consisted of eight 2-hour weekly sessions and a 7-hour full-day retreat, with different themes for each class, guided mindfulness exercises, feedback and discussion, homework review, and psychoeducation. The active control group comprised a 1-hour physical exercise and a standardised health education of the specific theme with group discussion (eg fall prevention, chronic pain). Participants were assessed before and after the 8-week intervention for four outcome measures: the Hamilton Depression Rating Scale (HAMD), the Ruminative Response Scale (RRS), the Autobiographical Memory Test (AMT), and the Mindful Attention Awareness Scale (MAAS). RESULTS There was a significant reduction in severity of depressive symptoms (HAMD score) in both the MBCT group (F(1, 27) = 35.9, p < 0.001, η2 = 0.57) and the active control group (F(1, 28) = 9.29, p < 0.01, η2 = 0.24), but only the MBCT group showed substantial improvements in autobiographical memory specificity (AMT score), rumination (RRS score), and mindfulness (MAAS score). CONCLUSION Although both MBCT and active control programme decrease the severity of depressive symptoms in older adults, only MBCT improves AMS, rumination, and mindfulness. Our findings provide empirical support for the theoretical underpinnings of MBCT. Older adults with more severe depression and more severe dysfunctional cognition may benefit more from the specific therapeutic effects of MBCT.
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Affiliation(s)
- V W Y Shih
- Department of Psychiatry, LKS Faculty of Medicine, The University of Hong Kong
| | - W C Chan
- Department of Psychiatry, LKS Faculty of Medicine, The University of Hong Kong
| | - O K Tai
- Department of Psychiatry, LKS Faculty of Medicine, The University of Hong Kong
| | - H L Wong
- Department of Psychiatry, LKS Faculty of Medicine, The University of Hong Kong
| | - C P W Cheng
- Department of Psychiatry, LKS Faculty of Medicine, The University of Hong Kong
| | - C S M Wong
- Department of Psychiatry, LKS Faculty of Medicine, The University of Hong Kong
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Wong HL, Lau HY, Siu JCW. Imaging Findings and Clinical Perspectives of Acute Necrotising Encephalopathy: Report of Two Cases. Hong Kong Journal of Radiology 2020. [DOI: 10.12809/hkjr2017177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- HL Wong
- Department of Radiology, Tuen Mun Hospital, Tuen Mun, Hong Kong
| | - HY Lau
- Department of Radiology, Tuen Mun Hospital, Tuen Mun, Hong Kong
| | - JCW Siu
- Department of Radiology, Tuen Mun Hospital, Tuen Mun, Hong Kong
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Liu Z, Ko CH, Ng CF, Wong HL, Zhang JF, Lam PK, Poon WS, Leung PC. Antioxidative effect of Gastrodiae Rhizoma-containing herbal formula in PC12 cell model: abridged secondary publication. Hong Kong Med J 2020; 26 Suppl 6:44-46. [PMID: 33229605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023] Open
Affiliation(s)
- Z Liu
- Institute of Chinese Medicine, The Chinese University of Hong Kong
| | - C H Ko
- Institute of Chinese Medicine, The Chinese University of Hong Kong
- State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong
| | - C F Ng
- Institute of Chinese Medicine, The Chinese University of Hong Kong
- State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong
| | - H L Wong
- Institute of Chinese Medicine, The Chinese University of Hong Kong
- State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong
| | - J F Zhang
- Department of Orthopaedic and Traumatology, The Chinese University of Hong Kong, Prince of Wales Hospital
| | - P K Lam
- Department of Surgery, The Chinese University of Hong Kong, Prince of Wales, Hospital
| | - W S Poon
- Department of Surgery, The Chinese University of Hong Kong, Prince of Wales, Hospital
| | - P C Leung
- Institute of Chinese Medicine, The Chinese University of Hong Kong
- State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong
- Department of Orthopaedic and Traumatology, The Chinese University of Hong Kong, Prince of Wales Hospital
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Tan SN, Tee CS, Wong HL. Multiple shoot bud induction and plant regeneration studies of Pongamia pinnata. Plant Biotechnol (Tokyo) 2018; 35:325-334. [PMID: 31892819 PMCID: PMC6905217 DOI: 10.5511/plantbiotechnology.18.0711a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/11/2018] [Indexed: 06/10/2023]
Abstract
Pongamia pinnata is a legume plant which has great potential to be used as a biofuel feedstock. Conventional propagation of P. pinnata was found to be inefficient for mass propagation. Employing plant tissue culture techniques for micropropagation and further plant improvement of P. pinnata will be the right path to fulfill future challenges in biofuel production. This study aimed to establish a plant regeneration system for potential micropropagation and genetic manipulation of P. pinnata in future. In vitro nodal explants were used and Woody Plant Medium (WPM) containing 30 µM 6-benzylaminopurine (BAP) and 1 mM phloroglucinol (PG) was able to induce higher frequency of multiple shoot buds compared to other media investigated in this study. For shoot regeneration study, WPM containing 15 µM of zeatin and 1 mM PG was able to induce longer shoots while rooting of the regenerated shoots was enhanced by WPM supplemented with indole-3-butyric acid (IBA) in combination with silver thiosulphate (STS). A simple and effective acclimatisation protocol was established with very high survival frequency of regenerated plantlets. Root nodulation of the successfully acclimatised plants was also observed. In short, multiple shoot buds were successfully induced, regenerated and rooted in vitro. The rooted plantlets were successfully acclimatised and grown healthily. It was concluded that a successful plant regeneration protocol of P. pinnata was achieved for potential application in micropropagation and genetic manipulation.
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Affiliation(s)
- Si Nan Tan
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - Chong Siang Tee
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - Hann Ling Wong
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak, Malaysia
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Yeap YH, Koay TW, Wong HL, Lim BH. Dissection of Synechococcus Rubisco Large Subunit Sections Involved in Holoenzyme Formation in Escherichia coli by Combinatorial Section Swapping and Sequence Analyses. SAINS MALAYS 2018. [DOI: 10.17576/jsm-2018-4710-04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Wong HL, Akamatsu A, Wang Q, Higuchi M, Matsuda T, Okuda J, Kosami KI, Inada N, Kawasaki T, Kaneko-Kawano T, Nagawa S, Tan L, Kawano Y, Shimamoto K. In vivo monitoring of plant small GTPase activation using a Förster resonance energy transfer biosensor. Plant Methods 2018; 14:56. [PMID: 30002723 PMCID: PMC6035793 DOI: 10.1186/s13007-018-0325-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 06/29/2018] [Indexed: 05/05/2023]
Abstract
BACKGROUND Small GTPases act as molecular switches that regulate various plant responses such as disease resistance, pollen tube growth, root hair development, cell wall patterning and hormone responses. Thus, to monitor their activation status within plant cells is believed to be the key step in understanding their roles. RESULTS We have established a plant version of a Förster resonance energy transfer (FRET) probe called Ras and interacting protein chimeric unit (Raichu) that can successfully monitor activation of the rice small GTPase OsRac1 during various defence responses in cells. Here, we describe the protocol for visualizing spatiotemporal activity of plant Rac/ROP GTPase in living plant cells, transfection of rice protoplasts with Raichu-OsRac1 and acquisition of FRET images. CONCLUSIONS Our protocol should be adaptable for monitoring activation for other plant small GTPases and protein-protein interactions for other FRET sensors in various plant cells.
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Affiliation(s)
- Hann Ling Wong
- Laboratory of Plant Molecular Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192 Japan
- Present Address: Department of Biological Science, University Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak Malaysia
| | - Akira Akamatsu
- Laboratory of Plant Molecular Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192 Japan
- Present Address: Department of Bioscience, Kwansei Gakuin University, 2-1 Gakuen, Sanda, 669-1337 Japan
| | - Qiong Wang
- Present Address: Signal Transduction and Immunity Group, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, No. 3888 Chenhua Road, Shanghai, 201602 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Masayuki Higuchi
- Laboratory of Plant Molecular Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192 Japan
| | - Tomonori Matsuda
- Laboratory of Plant Molecular Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192 Japan
| | - Jun Okuda
- Laboratory of Plant Molecular Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192 Japan
| | - Ken-ichi Kosami
- Present Address: Signal Transduction and Immunity Group, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, No. 3888 Chenhua Road, Shanghai, 201602 China
| | - Noriko Inada
- College of Life, Environment, and Advanced, Osaka Prefecture University Sciences, Sakai, Osaka 599-8531 Japan
| | - Tsutomu Kawasaki
- Laboratory of Plant Molecular Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192 Japan
- Present Address: Department of Advanced Bioscience, Kindai University, 3327-204 Nakamachi, Nara, 631-8505 Japan
| | | | - Shingo Nagawa
- Core Facility of Cell Biology, Shanghai Center for Plant Stress Biology, No. 3888 Chenhua Road, Shanghai, 201602 China
- Present Address: FAFU-UCR Joint Center and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian China
| | - Li Tan
- Core Facility of Cell Biology, Shanghai Center for Plant Stress Biology, No. 3888 Chenhua Road, Shanghai, 201602 China
| | - Yoji Kawano
- Laboratory of Plant Molecular Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192 Japan
- Present Address: Signal Transduction and Immunity Group, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, No. 3888 Chenhua Road, Shanghai, 201602 China
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka, Totsuka, Yokohama, Kanagawa 244-0813 Japan
| | - Ko Shimamoto
- Laboratory of Plant Molecular Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192 Japan
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Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a rate-limiting photosynthetic enzyme that catalyzes carbon fixation in the Calvin cycle. Much interest has been devoted to engineering this ubiquitous enzyme with the goal of increasing plant growth. However, experiments that have successfully produced improved Rubisco variants, via directed evolution in Escherichia coli, are limited to bacterial Rubisco because the eukaryotic holoenzyme cannot be produced in E. coli. The present study attempts to determine the specific differences between bacterial and eukaryotic Rubisco large subunit primary structure that are responsible for preventing heterologous eukaryotic holoenzyme formation in E. coli. A series of chimeric Synechococcus Rubiscos were created in which different sections of the large subunit were swapped with those of the homologous Chlamydomonas Rubisco. Chimeric holoenzymes that can form in vivo would indicate that differences within the swapped sections do not disrupt holoenzyme formation. Large subunit residues 1-97, 198-247 and 448-472 were successfully swapped without inhibiting holoenzyme formation. In all ten chimeras, protein expression was observed for the separate subunits at a detectable level. As a first approximation, the regions that can tolerate swapping may be targets for future engineering.
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Affiliation(s)
- Teng Wei Koay
- Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman
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13
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Tie J, Kinde I, Wang Y, Wong HL, Roebert J, Christie M, Tacey M, Wong R, Singh M, Karapetis CS, Desai J, Tran B, Strausberg RL, Diaz LA, Papadopoulos N, Kinzler KW, Vogelstein B, Gibbs P. Circulating tumor DNA as an early marker of therapeutic response in patients with metastatic colorectal cancer. Ann Oncol 2015; 26:1715-22. [PMID: 25851626 DOI: 10.1093/annonc/mdv177] [Citation(s) in RCA: 459] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/20/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Early indicators of treatment response in metastatic colorectal cancer (mCRC) could conceivably be used to optimize treatment. We explored early changes in circulating tumor DNA (ctDNA) levels as a marker of therapeutic efficacy. PATIENTS AND METHODS This prospective study involved 53 mCRC patients receiving standard first-line chemotherapy. Both ctDNA and CEA were assessed in plasma collected before treatment, 3 days after treatment and before cycle 2. Computed tomography (CT) scans were carried out at baseline and 8-10 weeks and were centrally assessed using RECIST v1.1 criteria. Tumors were sequenced using a panel of 15 genes frequently mutated in mCRC to identify candidate mutations for ctDNA analysis. For each patient, one tumor mutation was selected to assess the presence and the level of ctDNA in plasma samples using a digital genomic assay termed Safe-SeqS. RESULTS Candidate mutations for ctDNA analysis were identified in 52 (98.1%) of the tumors. These patient-specific candidate tissue mutations were detectable in the cell-free DNA from the plasma of 48 of these 52 patients (concordance 92.3%). Significant reductions in ctDNA (median 5.7-fold; P < 0.001) levels were observed before cycle 2, which correlated with CT responses at 8-10 weeks (odds ratio = 5.25 with a 10-fold ctDNA reduction; P = 0.016). Major reductions (≥10-fold) versus lesser reductions in ctDNA precycle 2 were associated with a trend for increased progression-free survival (median 14.7 versus 8.1 months; HR = 1.87; P = 0.266). CONCLUSIONS ctDNA is detectable in a high proportion of treatment naïve mCRC patients. Early changes in ctDNA during first-line chemotherapy predict the later radiologic response.
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Affiliation(s)
- J Tie
- Division of Systems Biology and Personalised Medicine, Walter and Eliza Hall Institute of Medical Research, Melbourne Department of Medical Oncology, Western Hospital, Melbourne Department of Medical Oncology, The Royal Melbourne Hospital, Melbourne Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia
| | - I Kinde
- Ludwig Center for Cancer Genetics and Therapeutics, Howard Hughes Medical Institute at Johns Hopkins Kimmel Cancer Center, Baltimore, USA
| | - Y Wang
- Ludwig Center for Cancer Genetics and Therapeutics, Howard Hughes Medical Institute at Johns Hopkins Kimmel Cancer Center, Baltimore, USA
| | - H L Wong
- Division of Systems Biology and Personalised Medicine, Walter and Eliza Hall Institute of Medical Research, Melbourne Department of Medical Oncology, The Royal Melbourne Hospital, Melbourne Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia Faculty of Medicine, Nursing and Health Sciences, Monash University, Eastern Health Clinical School, Melbourne
| | | | - M Christie
- Division of Systems Biology and Personalised Medicine, Walter and Eliza Hall Institute of Medical Research, Melbourne Department of Medical Oncology, The Royal Melbourne Hospital, Melbourne Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia
| | - M Tacey
- Melbourne EpiCentre, Department of Medicine, The University of Melbourne, Melbourne
| | - R Wong
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Eastern Health Clinical School, Melbourne
| | - M Singh
- Andrew Love Cancer Centre, Barwon Health, Geelong
| | - C S Karapetis
- Department of Medical Oncology, Flinders University, Adelaide, Australia
| | - J Desai
- Division of Systems Biology and Personalised Medicine, Walter and Eliza Hall Institute of Medical Research, Melbourne Department of Medical Oncology, The Royal Melbourne Hospital, Melbourne Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia
| | - B Tran
- Division of Systems Biology and Personalised Medicine, Walter and Eliza Hall Institute of Medical Research, Melbourne Department of Medical Oncology, Western Hospital, Melbourne Department of Medical Oncology, The Royal Melbourne Hospital, Melbourne Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia
| | | | - L A Diaz
- Ludwig Center for Cancer Genetics and Therapeutics, Howard Hughes Medical Institute at Johns Hopkins Kimmel Cancer Center, Baltimore, USA
| | - N Papadopoulos
- Ludwig Center for Cancer Genetics and Therapeutics, Howard Hughes Medical Institute at Johns Hopkins Kimmel Cancer Center, Baltimore, USA
| | - K W Kinzler
- Ludwig Center for Cancer Genetics and Therapeutics, Howard Hughes Medical Institute at Johns Hopkins Kimmel Cancer Center, Baltimore, USA
| | - B Vogelstein
- Ludwig Center for Cancer Genetics and Therapeutics, Howard Hughes Medical Institute at Johns Hopkins Kimmel Cancer Center, Baltimore, USA
| | - P Gibbs
- Division of Systems Biology and Personalised Medicine, Walter and Eliza Hall Institute of Medical Research, Melbourne Department of Medical Oncology, Western Hospital, Melbourne Department of Medical Oncology, The Royal Melbourne Hospital, Melbourne Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia Ludwig Institute for Cancer Research, New York, USA Ludwig Institute for Cancer Research, Melbourne, Australia
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14
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Kumar D, Neo KE, Rub MA, Tan ZL, Beh WL, Wong HL. Study of copper(II)–glycylphenylalanine complex with ninhydrin in aqueous and cationic CTAB micellar media: A kinetic and mechanistic approach. J Mol Liq 2015. [DOI: 10.1016/j.molliq.2014.10.041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Kumar D, Neo KE, Rub MA, Tan ZL, Beh WL, Wong HL. Interaction of Metal–Dipeptide Complex with Ninhydrin in the Absence and Presence of Conventional CTAB Surfactant. J DISPER SCI TECHNOL 2015. [DOI: 10.1080/01932691.2014.982286] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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16
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Akamatsu A, Uno K, Kato M, Wong HL, Shimamoto K, Kawano Y. New insights into the dimerization of small GTPase Rac/ROP guanine nucleotide exchange factors in rice. Plant Signal Behav 2015; 10:e1044702. [PMID: 26251883 PMCID: PMC4622004 DOI: 10.1080/15592324.2015.1044702] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 04/21/2015] [Accepted: 04/21/2015] [Indexed: 05/19/2023]
Abstract
Molecular links between receptor-kinases and Rac/ROP family small GTPases mediated by activator guanine nucleotide exchange factors (GEFs) govern diverse biological processes. However, it is unclear how the Rac/ROP GTPases orchestrate such a wide variety of activities. Here, we show that rice OsRacGEF1 forms homodimers, and heterodimers with OsRacGEF2, at the plasma membrane (PM) and the endoplasmic reticulum (ER). OsRacGEF2 does not bind directly to the receptor-like kinase (RLK) OsCERK1, but forms a complex with OsCERK1 through OsRacGEF1 at the ER. This complex is transported from ER to the PM and there associates with OsRac1, resulting in the formation of a stable immune complex. Such RLK-GEF heterodimer complexes may explain the diversity of Rac/ROP family GTPase signalings.
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Affiliation(s)
- Akira Akamatsu
- Laboratory of Plant Molecular Genetics; Graduate School of Biological Sciences; Nara Institute of Science and Technology; Ikoma, Japan
- Cell and Developmental Biology; John Innes Center; Norwich, United Kingdom
- These authors equally contributed to this work
| | - Kazumi Uno
- Laboratory of Plant Molecular Genetics; Graduate School of Biological Sciences; Nara Institute of Science and Technology; Ikoma, Japan
- These authors equally contributed to this work
| | - Midori Kato
- Laboratory of Plant Molecular Genetics; Graduate School of Biological Sciences; Nara Institute of Science and Technology; Ikoma, Japan
| | - Hann Ling Wong
- Laboratory of Plant Molecular Genetics; Graduate School of Biological Sciences; Nara Institute of Science and Technology; Ikoma, Japan
- Deptartment of Biological Science; University Tunku Abdul Rahman Jalan Universiti; Bandar Barat Kampar, Malaysia
| | - Ko Shimamoto
- Laboratory of Plant Molecular Genetics; Graduate School of Biological Sciences; Nara Institute of Science and Technology; Ikoma, Japan
| | - Yoji Kawano
- Laboratory of Plant Molecular Genetics; Graduate School of Biological Sciences; Nara Institute of Science and Technology; Ikoma, Japan
- Shanghai Center for Plant Stress Biology; Shanghai, PR China
- Correspondence to: Yoji Kawano;
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17
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Goldstein J, Tran B, Ensor J, Gibbs P, Wong HL, Wong SF, Vilar E, Tie J, Broaddus R, Kopetz S, Desai J, Overman MJ. Multicenter retrospective analysis of metastatic colorectal cancer (CRC) with high-level microsatellite instability (MSI-H). Ann Oncol 2014; 25:1032-8. [PMID: 24585723 DOI: 10.1093/annonc/mdu100] [Citation(s) in RCA: 196] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The microsatellite instability-high (MSI-H) phenotype, present in 15% of early colorectal cancer (CRC), confers good prognosis. MSI-H metastatic CRC is rare and its impact on outcomes is unknown. We describe survival outcomes and the impact of chemotherapy, metastatectomy, and BRAF V600E mutation status in the largest reported cohort of MSI-H metastatic colorectal cancer (CRC). PATIENTS AND METHODS A retrospective review of 55 MSI-H metastatic CRC patients from two institutions, Royal Melbourne Hospital (Australia) and The University of Texas MD Anderson Cancer Center (United States), was conducted. Statistical analyses utilized Kaplan-Meier method, Log-rank test, and Cox proportional hazards models. RESULTS Median age was 67 years (20-90), 58% had poor differentiation, and 45% had stage IV disease at presentation. Median overall survival (OS) from metastatic disease was 15.4 months. Thirteen patients underwent R0/R1 metastatectomies, with median OS from metastatectomy 33.8 months. Thirty-one patients received first-line systemic chemotherapy for metastatic disease with median OS from the start of chemotherapy 11.5 months. No statistically significant difference in progression-free survival or OS was seen between fluoropyrimidine, oxaliplatin, or irinotecan based chemotherapy. BRAF V600E mutation was present in 14 of 47 patients (30%). BRAF V600E patients demonstrated significantly worse median OS; 10.1 versus 17.3 months, P = 0.03. In multivariate analyses, BRAF V600E mutants had worse OS (HR 4.04; P = 0.005), while patients undergoing metastatectomy (HR 0.11; P = <0.001) and patients who initially presented as stage IV disease had improved OS (HR 0.27; P = 0.003). CONCLUSIONS Patients with MSI-H metastatic CRC do not appear to have improved outcomes. BRAF V600E mutation is a poor prognostic factor in MSI-H metastatic CRC.
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Affiliation(s)
- J Goldstein
- Department of Gastrointestinal Medical Oncology, MD Anderson Cancer Center, Houston, USA
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18
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Wamaitha MJ, Yamamoto R, Wong HL, Kawasaki T, Kawano Y, Shimamoto K. OsRap2.6 transcription factor contributes to rice innate immunity through its interaction with Receptor for Activated Kinase-C 1 (RACK1). Rice (N Y) 2012; 5:35. [PMID: 24280008 PMCID: PMC4883712 DOI: 10.1186/1939-8433-5-35] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 11/06/2012] [Indexed: 05/03/2023]
Abstract
BACKGROUND The rice small GTPase OsRac1 is a molecular switch in rice innate immunity. The Receptor for Activated Kinase C-1 (RACK1) interacts with OsRac1 to suppress the growth of the rice blast fungus, Magnaporthe oryzae. RACK1 has two homologs in rice, RACK1A and RACK1B. Overexpressing RACK1A enhances resistance to the rice blast fungus. However, RACK1A downstream signals are largely unknown. RESULTS Here, we report the identification of OsRap2.6, a transcription factor that interacts with RACK1A. We found a 94% similarity between the OsRap2.6 AP2 domain and Arabidopsis Rap2.6 (AtRap2.6). Bimolecular fluorescence complementation (BiFC) assays in rice protoplasts using tagged OsRap2.6 and RACK1A with the C-terminal and N-terminal fragments of Venus (Vc/Vn) indicated that OsRap2.6 and RACK1A interacted and localized in the nucleus and the cytoplasm. Moreover, OsRap2.6 and OsMAPK3/6 interacted in the nucleus and the cytoplasm. Expression of defense genes PAL1 and PBZ1 as well as OsRap2.6 was induced after chitin treatment. Disease resistance analysis using OsRap2.6 RNAi and overexpressing (Ox) plants infected with the rice blast fungus indicated that OsRap2.6 RNAi plants were highly susceptible, whereas OsRap2.6 Ox plants had an increased resistance to the compatible blast fungus. CONCLUSIONS OsRap2.6 contributes to rice innate immunity through its interaction with RACK1A in compatible interactions.
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Affiliation(s)
- Mwathi Jane Wamaitha
- />Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192 Japan
| | - Risa Yamamoto
- />Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192 Japan
| | - Hann Ling Wong
- />Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192 Japan
- />Universiti Tunku Abdul Rahman Jalan Universiti, Bandar Barat, Kampar 31900 Malaysia
| | - Tsutomu Kawasaki
- />Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192 Japan
- />Department of Advanced Bioscience, Graduate School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara, 631-8505 Japan
| | - Yoji Kawano
- />Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192 Japan
| | - Ko Shimamoto
- />Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192 Japan
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19
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Zurina Z, Wong HL, Jasminder K, Neoh SH, Cheah IGS. Parotid abscess in a late premature infant: a case report. Med J Malaysia 2012; 67:631-632. [PMID: 23770964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Parotid abscess is uncommon in neonates. It is frequently related to prematurity, prolonged gavage feeding and dehydration. We report a case of a late preterm infant who developed the classical manifestation of unilateral acute Staphylococcus aureus suppurative parotitis progressing to formation of abscess which responded to surgical drainage and antibiotic therapy.
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Affiliation(s)
- Z Zurina
- Universiti Putra Malaysia, Faculty of Medicine and Health Sciences, Department of Paediatrics, 43400 UPM Serdang, Selangor, Malaysia.
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20
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Kim SH, Oikawa T, Kyozuka J, Wong HL, Umemura K, Kishi-Kaboshi M, Takahashi A, Kawano Y, Kawasaki T, Shimamoto K. The bHLH Rac Immunity1 (RAI1) Is Activated by OsRac1 via OsMAPK3 and OsMAPK6 in Rice Immunity. Plant Cell Physiol 2012; 53:740-54. [PMID: 22437844 DOI: 10.1093/pcp/pcs033] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The Rac/Rop GTPase OsRac1 plays an essential role in rice immunity. However, the regulatory genes acting downstream of OsRac1 are largely unknown. We focused on the RAI1 gene, which is up-regulated in suspension cells expressing a constitutively active form of OsRac1. RAI1 encodes a putative basic helix-loop-helix transcription factor. A microarray analysis of cells transformed with an inducible RAI1 construct showed increased expression of PAL1 and OsWRKY19 genes after induction, suggesting that these genes are regulated by RAI1. This was confirmed using RAI1 T-DNA activation-tagged and RNA interference lines. The PAL1 and OsWRKY19 genes were also up-regulated by sphingolipid and chitin elicitors, and the RAI1 activation-tagged plants had increased resistance to a rice blast fungus. These results indicated that RAI1 is involved in defense responses in rice. RAI1 interacted with OsMAPK3 and OsMAPK6 proteins in vivo and in vitro. Also, RAI1 was phosphorylated by OsMAPK3/6 and OsMKK4-dd in vitro. Overexpression of OsMAPK6 and/or OsMAPK3 together with OsMKK4-dd increased PAL1 and OsWRKY19 expression in rice protoplasts. Therefore, the regulation of PAL1 and OsWRKY19 expression by RAI1 could be controlled via an OsMKK4-OsMAPK3/6 cascade. Co-immunoprecipitation assays indicated that OsMAPK3 and OsRac1 occur in the same complex as OsMAPK6. Taken together, our results indicate that RAI1 could be regulated by OsRac1 through an OsMAPK3/6 cascade. In this study, we have identified RAI1 as the first transcription factor acting downstream of OsRac1. This work will help us to understand the immune system regulated by OsRac1 in rice and its orthologs in other plant species.
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Affiliation(s)
- Sung-Hyun Kim
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Japan
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21
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Je BI, Piao HL, Park SJ, Park SH, Kim CM, Xuan YH, Park SH, Huang J, Do Choi Y, An G, Wong HL, Fujioka S, Kim MC, Shimamoto K, Han CD. RAV-Like1 maintains brassinosteroid homeostasis via the coordinated activation of BRI1 and biosynthetic genes in rice. Plant Cell 2010; 22:1777-91. [PMID: 20581303 PMCID: PMC2910978 DOI: 10.1105/tpc.109.069575] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 05/21/2010] [Accepted: 06/09/2010] [Indexed: 05/18/2023]
Abstract
Temporal and spatial variation in the levels of and sensitivity to hormones are essential for the development of higher organisms. Traditionally, end-product feedback regulation has been considered as the key mechanism for the achievement of cellular homeostasis. Brassinosteroids (BRs) are plant steroid hormones that are perceived by the cell surface receptor kinase Brassinosteroid Insensitive1. Binding of these hormones to the receptor activates BR signaling and eventually suppresses BR synthesis. This report shows that RAVL1 regulates the expression of the BR receptor. Furthermore, RAVL1 is also required for the expression of the BR biosynthetic genes D2, D11, and BRD1 that are subject to BR negative feedback. Activation by RAVL1 was coordinated via E-box cis-elements in the promoters of the receptor and biosynthetic genes. Also, RAVL1 is necessary for the response of these genes to changes in cellular BR homeostasis. Genetic evidence is presented to strengthen the observation that the primary action of RAVL1 mediates the expression of genes involved in BR signaling and biosynthesis. This study thus describes a regulatory circuit modulating the homeostasis of BR in which RAVL1 ensures the basal activity of both the signaling and the biosynthetic pathways.
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Affiliation(s)
- Byoung Il Je
- Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
| | - Hai Long Piao
- Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
| | - Soon Ju Park
- Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
| | - Sung Han Park
- National Academy of Agricultural Science, Rural Development Administration, Suwon 441-857, Korea
| | - Chul Min Kim
- Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
| | - Yuan Hu Xuan
- Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
| | - Su Hyun Park
- Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
| | - Jin Huang
- Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
| | - Yang Do Choi
- School of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
| | - Gynheung An
- Department of Plant Molecular Systems Biotechnology, Crop Biotechnology Institute, Kyung Hee University, Yongin 446-701, Korea
| | - Hann Ling Wong
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan
| | - Shozo Fujioka
- RIKEN Advanced Science Institute, Wako-shi, Saitama 351-0198, Japan
| | - Min-Chul Kim
- Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
| | - Ko Shimamoto
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan
| | - Chang-deok Han
- Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center, Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
- Address correspondence to
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22
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Chen L, Hamada S, Fujiwara M, Zhu T, Thao NP, Wong HL, Krishna P, Ueda T, Kaku H, Shibuya N, Kawasaki T, Shimamoto K. The Hop/Sti1-Hsp90 chaperone complex facilitates the maturation and transport of a PAMP receptor in rice innate immunity. Cell Host Microbe 2010; 7:185-96. [PMID: 20227662 DOI: 10.1016/j.chom.2010.02.008] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 01/14/2010] [Accepted: 02/19/2010] [Indexed: 01/22/2023]
Abstract
Recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs) represents a critical first step of innate defense in plants and animals. However, maturation and transport of PRRs are not well understood. We find that the rice chitin receptor OsCERK1 interacts with Hsp90 and its cochaperone Hop/Sti1 in the endoplasmic reticulum (ER). Hop/Sti1 and Hsp90 are required for efficient transport of OsCERK1 from the ER to the plasma membrane (PM) via a pathway dependent on Sar1, a small GTPase which regulates ER-to-Golgi trafficking. Further, Hop/Sti1 and Hsp90 are present at the PM in a complex (designated the "defensome") with OsRac1, a plant-specific Rho-type GTPase. Finally, Hop/Sti1 was required for chitin-triggered immunity and resistance to rice blast fungus. Our results suggest that the Hop/Sti1-Hsp90 chaperone complex plays an important and likely conserved role in the maturation and transport of PRRs and may function to link PRRs and Rac/Rop GTPases.
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Affiliation(s)
- Letian Chen
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Takayama, Ikoma, Japan
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23
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Kawano Y, Akamatsu A, Hayashi K, Housen Y, Okuda J, Yao A, Nakashima A, Takahashi H, Yoshida H, Wong HL, Kawasaki T, Shimamoto K. Activation of a Rac GTPase by the NLR Family Disease Resistance Protein Pit Plays a Critical Role in Rice Innate Immunity. Cell Host Microbe 2010; 7:362-75. [DOI: 10.1016/j.chom.2010.04.010] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 02/01/2010] [Accepted: 04/22/2010] [Indexed: 12/21/2022]
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24
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Chen L, Shiotani K, Togashi T, Miki D, Aoyama M, Wong HL, Kawasaki T, Shimamoto K. Analysis of the Rac/Rop small GTPase family in rice: expression, subcellular localization and role in disease resistance. Plant Cell Physiol 2010; 51:585-95. [PMID: 20203239 DOI: 10.1093/pcp/pcq024] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Plant-specific Rac/Rop small GTPases function as molecular switches for numerous signal transduction events, including defense responses. To understand the function of each of the seven Rac/Rop family members in rice, we studied the tissue-specific expression patterns of Rac/Rop genes by semi-quantitative reverse transcription-PCR (RT-PCR), and also Rac/Rop subcellular localization using green fluorescent protein (GFP) fusion proteins in transient expression systems. We also investigated the roles of these genes in disease resistance by testing single Rac/Rop-RNAi (RNA interference) plants against the rice blast pathogen Magnaporthe grisea. Our studies show that expression of OsRac2, 6 and 7 is very low in leaf blades, and reveal a strong correlation between the number of lysine and/or arginine (KR) residues in the polybasic region of Rac/Rop GTPases and their subcellular distribution in vivo. Infection assays showed that OsRac1 is a positive regulator of blast resistance, confirming previous observations, whereas OsRac4 and OsRac5 are negative regulators of blast resistance. OsRac6 may make minor contributions to disease resistance, while OsRac3 and OsRac7 are probably not involved in defense. Therefore, our study suggests that the rice Rac/Rop family plays multiple roles in diverse cellular activities and has both positive and negative functions in disease resistance.
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Affiliation(s)
- Letian Chen
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, 630-0192 Japan
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25
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Fujiwara T, Maisonneuve S, Isshiki M, Mizutani M, Chen L, Wong HL, Kawasaki T, Shimamoto K. Sekiguchi lesion gene encodes a cytochrome P450 monooxygenase that catalyzes conversion of tryptamine to serotonin in rice. J Biol Chem 2010; 285:11308-13. [PMID: 20150424 DOI: 10.1074/jbc.m109.091371] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Serotonin is a well known neurotransmitter in mammals and plays an important role in various mental functions in humans. In plants, the serotonin biosynthesis pathway and its function are not well understood. The rice sekiguchi lesion (sl) mutants accumulate tryptamine, a candidate substrate for serotonin biosynthesis. We isolated the SL gene by map-based cloning and found that it encodes CYP71P1 in a cytochrome P450 monooxygenase family. A recombinant SL protein exhibited tryptamine 5-hydroxylase enzyme activity and catalyzed the conversion of tryptamine to serotonin. This pathway is novel and has not been reported in mammals. Expression of SL was induced by the N-acetylchitooligosaccharide (chitin) elicitor and by infection with Magnaporthe grisea, a causal agent for rice blast disease. Exogenously applied serotonin induced defense gene expression and cell death in rice suspension cultures and increased resistance to rice blast infection in plants. We also found that serotonin-induced defense gene expression is mediated by the RacGTPase pathway and by the G alpha subunit of the heterotrimeric G protein. These results suggest that serotonin plays an important role in rice innate immunity.
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Affiliation(s)
- Tadashi Fujiwara
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0192, Japan
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Oda T, Hashimoto H, Kuwabara N, Akashi S, Hayashi K, Kojima C, Wong HL, Kawasaki T, Shimamoto K, Sato M, Shimizu T. Structure of the N-terminal regulatory domain of a plant NADPH oxidase and its functional implications. J Biol Chem 2010; 285:1435-45. [PMID: 19864426 PMCID: PMC2801269 DOI: 10.1074/jbc.m109.058909] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 10/08/2009] [Indexed: 12/21/2022] Open
Abstract
Plant NADPH oxidases (Rboh, for respiratory burst oxidase homolog) produce reactive oxygen species that are key regulators of various cellular events including plant innate immunity. Rbohs possess a highly conserved cytoplasmic N-terminal region containing two EF-hand motifs that regulate Rboh activity. Rice (Oryza sativa) RbohB (OsRbohB) is regulated by the direct binding of a small GTPase (Rac1) to this regulatory region as well as by Ca(2+) binding to the EF-hands. Here, we present the atomic structure of the N-terminal region of OsRbohB. The structure reveals that OsRbohB forms a unique dimer stabilized by swapping the EF-hand motifs. We identified two additional EF-hand-like motifs that were not predicted from sequence data so far. These EF-hand-like motifs together with the swapped EF-hands form a structure similar to that found in calcineurin B. We observed conformational changes mediated by Ca(2+) binding to only one EF-hand. Structure-based in vitro pulldown assays and NMR titration experiments defined the OsRac1 binding interface within the coiled-coil region created by swapping the EF-hands. In addition, we demonstrate a direct intramolecular interaction between the N and C terminus, and that the complete N-terminal cytoplasmic region is required for this interaction. The structural features and intramolecular interactions characterized here might be common elements shared by Rbohs that contribute to the regulation of reactive oxygen species production.
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Affiliation(s)
- Takashi Oda
- From the Graduate School of Nanobioscience, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 and
| | - Hiroshi Hashimoto
- From the Graduate School of Nanobioscience, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 and
| | - Naoyuki Kuwabara
- From the Graduate School of Nanobioscience, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 and
| | - Satoko Akashi
- From the Graduate School of Nanobioscience, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 and
| | | | | | - Hann Ling Wong
- Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Tsutomu Kawasaki
- Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Ko Shimamoto
- Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Mamoru Sato
- From the Graduate School of Nanobioscience, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 and
| | - Toshiyuki Shimizu
- From the Graduate School of Nanobioscience, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 and
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Abstract
Plants have to contend with biotic stress, such as disease, mechanical wounding, and herbivory, as well as abiotic stress, such as heat, cold, and salinity. An early warning system for these threats would prevent or reduce the damage suffered by plants. Such a warning system should allow the signal to be rapidly generated and sent over long distances. The study of systemic signaling in plants has been a major scientific challenge. Reactive oxygen species (ROS) are among the systemic signals that have been proposed. Now, the exciting discovery that systemic ROS signaling is mediated by an NADPH (nicotinamide adenine dinucleotide phosphate, reduced form) oxidase opens the door to understanding the molecular mechanisms that initiate and propagate a rapid systemic signal.
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Affiliation(s)
- Hann Ling Wong
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, 630-0192 Nara, Japan
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28
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Nakashima A, Chen L, Thao NP, Fujiwara M, Wong HL, Kuwano M, Umemura K, Shirasu K, Kawasaki T, Shimamoto K. RACK1 functions in rice innate immunity by interacting with the Rac1 immune complex. Plant Cell 2008; 20:2265-79. [PMID: 18723578 PMCID: PMC2553611 DOI: 10.1105/tpc.107.054395] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
A small GTPase, Rac1, plays a key role in rice (Oryza sativa) innate immunity as part of a complex of regulatory proteins. Here, we used affinity column chromatography to identify rice RACK1 (for Receptor for Activated C-Kinase 1) as an interactor with Rac1. RACK1 functions in various mammalian signaling pathways and is involved in hormone signaling and development in plants. Rice contains two RACK1 genes, RACK1A and RACK1B, and the RACK1A protein interacts with the GTP form of Rac1. Rac1 positively regulates RACK1A at both the transcriptional and posttranscriptional levels. RACK1A transcription was also induced by a fungal elicitor and by abscisic acid, jasmonate, and auxin. Analysis of transgenic rice plants and cell cultures indicates that RACK1A plays a role in the production of reactive oxygen species (ROS) and in resistance against rice blast infection. Overexpression of RACK1A enhances ROS production in rice seedlings. RACK1A was shown to interact with the N terminus of NADPH oxidase, RAR1, and SGT1, key regulators of plant disease resistance. These results suggest that RACK1A functions in rice innate immunity by interacting with multiple proteins in the Rac1 immune complex.
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Affiliation(s)
- Ayako Nakashima
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0192, Japan
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29
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Wong HL, Pinontoan R, Hayashi K, Tabata R, Yaeno T, Hasegawa K, Kojima C, Yoshioka H, Iba K, Kawasaki T, Shimamoto K. Regulation of rice NADPH oxidase by binding of Rac GTPase to its N-terminal extension. Plant Cell 2007; 19:4022-34. [PMID: 18156215 PMCID: PMC2217649 DOI: 10.1105/tpc.107.055624] [Citation(s) in RCA: 313] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2007] [Revised: 11/07/2007] [Accepted: 12/07/2007] [Indexed: 05/17/2023]
Abstract
Reactive oxygen species (ROS) produced by NADPH oxidase play critical roles in various cellular activities, including plant innate immunity response. In contrast with the large multiprotein NADPH oxidase complex of phagocytes, in plants, only the homologs of the catalytic subunit gp91phox and the cytosolic regulator small GTPase Rac are found. Plant homologs of the gp91phox subunit are known as Rboh (for respiratory burst oxidase homolog). Although numerous Rboh have been isolated in plants, the regulation of enzymatic activity remains unknown. All rboh genes identified to date possess a conserved N-terminal extension that contains two Ca2+ binding EF-hand motifs. Previously, we ascertained that a small GTPase Rac (Os Rac1) enhanced pathogen-associated molecular pattern-induced ROS production and resistance to pathogens in rice (Oryza sativa). In this study, using yeast two-hybrid assay, we found that interaction between Rac GTPases and the N-terminal extension is ubiquitous and that a substantial part of the N-terminal region of Rboh, including the two EF-hand motifs, is required for the interaction. The direct Rac-Rboh interaction was supported by further studies using in vitro pull-down assay, a nuclear magnetic resonance titration experiment, and in vivo fluorescence resonance energy transfer (FRET) microscopy. The FRET analysis also suggests that cytosolic Ca2+ concentration may regulate Rac-Rboh interaction in a dynamic manner. Furthermore, transient coexpression of Os Rac1 and rbohB enhanced ROS production in Nicotiana benthamiana, suggesting that direct Rac-Rboh interaction may activate NADPH oxidase activity in plants. Taken together, the results suggest that cytosolic Ca2+ concentration may modulate NADPH oxidase activity by regulating the interaction between Rac GTPase and Rboh.
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Affiliation(s)
- Hann Ling Wong
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Ikoma, 630-0192 Nara, Japan
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30
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Ng FY, Wong HL, Yau WP, Chiu KY, Tang WM. Comparison of range of motion after standard and high-flexion posterior stabilised total knee replacement. Int Orthop 2007; 32:795-8. [PMID: 17891397 PMCID: PMC2898944 DOI: 10.1007/s00264-007-0409-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 05/14/2007] [Accepted: 05/15/2007] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to compare the range of motion after standard version posterior stabilised TKR and high-flexion version TKR in patients receiving bilateral total knee replacement. Thirty-five patients were recruited. The range of motion of the knees was measured clinically with a goniometer in both the pre-operative period and the most recent follow-up. It was found that the pre-operative range of motion was comparable in the two groups. The average post-operative flexion was 105 degrees +/- 13 degrees in the standard version group and 106 degrees +/- 14 degrees in the high-flexion design group (p = 0.201, paired t-test; beta error = 0.073). A slight loss in flexion was observed in the standard version group (0.5 degrees ) as opposed to a slight gain in the high-flexion design group (2 degrees ). However, this was not statistically significant (p = 0.251, paired t-test; beta error = 0.105).
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Affiliation(s)
- F Y Ng
- Department of Orthopaedic and Traumatology, Queen Mary Hospital, The University of Hong Kong, No. 102, Pokfulam Road, Pokfulam, Hong Kong.
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31
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Fujiwara M, Wong HL, Shimamoto K. [New aspect of rice pathology research revealed by proteomics and bioimaging]. Tanpakushitsu Kakusan Koso 2007; 52:711-6. [PMID: 17566379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
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32
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Abstract
Florigen, the mobile signal that moves from an induced leaf to the shoot apex and causes flowering, has eluded identification since it was first proposed 70 years ago. Understanding the nature of the mobile flowering signal would provide a key insight into the molecular mechanism of floral induction. Recent studies suggest that the Arabidopsis FLOWERING LOCUS T (FT) gene is a candidate for encoding florigen. We show that the protein encoded by Hd3a, a rice ortholog of FT, moves from the leaf to the shoot apical meristem and induces flowering in rice. These results suggest that the Hd3a protein may be the rice florigen.
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Affiliation(s)
- Shojiro Tamaki
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan
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33
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Cornish AS, Ng WC, Ho VCM, Wong HL, Lam JCW, Lam PKS, Leung KMY. Trace metals and organochlorines in the bamboo shark Chiloscyllium plagiosum from the southern waters of Hong Kong, China. Sci Total Environ 2007; 376:335-45. [PMID: 17320935 DOI: 10.1016/j.scitotenv.2007.01.070] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 01/06/2007] [Accepted: 01/11/2007] [Indexed: 05/14/2023]
Abstract
The bamboo shark Chiloscyllium plagiosum is an abundant benthic species along the shallow continental shelf of Southeast Asia. It is commonly taken by fishermen in China, India, Taiwan and Thailand for human consumption. This study measured trace metal and organochlorine concentrations in C. plagiosum collected from the southern waters of Hong Kong, China. Metals (Ag, Cd, Cr, Cu, Mn, Ni, Pb and Zn) were measured in three different tissues: dorsal muscle, spleen and liver. Polychlorinated biphenyls (PCBs) and chlorinated pesticides in the dorsal muscle were identified and quantified using gas chromatography. Metal concentrations varied among the three different tissues, with liver having higher levels of Ag and Cd, and spleen possessing higher levels of Cu and Mn. Both Ni and Pb in all tissues were below the detection limit. Tissue concentrations of Cr, Cu, Mn and Zn generally decreased with increasing body weight whilst no significant concentration-size relationship was found for other metals. In muscle tissues, total PCBs ranged from 1.056-4.771 ng/g (wet wt.) with a median of 1.801 ng/g, while total DDTs ranged from 0.602-23.55 ng/g with a median of 1.109 ng/g, in which p,p'-DDE was the predominant metabolite. Levels of total hexachlorohexanes and cyclodienes were low. The pesticide p,p'-DDT was the only compound found to be positively correlated with body weight, indicating temporal bioaccumulation of this compound. Zn concentrations in the muscle of C. plagiosum were comparatively higher than recorded in other shark species, however, concentrations of other metals and organochlorines were relatively low. C. plagiosum feeds primarily on polychaetes, shrimps and small fishes, and thus is unlikely to contain levels of contaminants of human health concern.
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Affiliation(s)
- Andrew S Cornish
- The Swire Institute of Marine Science, Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
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34
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Murphy MB, Hecker M, Coady KK, Tompsett AR, Jones PD, Newsted JL, Wong HL, du Preez LH, Solomon KR, Carr JA, Smith EE, Kendall RJ, Van der Kraak G, Giesy JP. Sediment TCDD-EQs and EROD and MROD activities in Ranid frogs from agricultural and nonagricultural sites in Michigan (USA). Arch Environ Contam Toxicol 2006; 51:467-77. [PMID: 16788744 DOI: 10.1007/s00244-005-0183-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Accepted: 12/26/2005] [Indexed: 05/10/2023]
Abstract
In vitro studies have demonstrated atrazine-mediated induction of 7-ethoxyresorufin O-deethylase (EROD) activity. EROD is an enzyme active in the metabolism of many compounds, including many xenobiotics. These studies have suggested that atrazine may affect reproductive function by altering steroid metabolism. The goal of this study was to determine whether relationships could be detected between measured atrazine concentrations in surface waters and the liver-somatic index (LSI) and EROD and 7-methoxyresorufin O-deethylase (MROD) activities in the livers of ranid frogs. In addition, sediment dioxin toxic equivalents (TCDD-EQs) were determined using the H4IIE-luc cell bioassay. Adult and juvenile green frogs (Rana clamitans), bullfrogs (R. catesbeiana), and Northern leopard frogs (R. pipiens) were collected from areas with extensive corn cultivation and areas where there was little agricultural activity in south central Michigan in the summer of 2003. Atrazine concentrations at nonagricultural sites ranged from less than the limit of quantification (0.17 microg atrazine/L) to 0.23 microg atrazine/L and did not exceed 1.2 microg atrazine/L at agricultural sites. Sediment TCDD-EQs were measurable only at one agricultural site. Of the measured parameters, only LSI values in adult male frogs differed significantly between agricultural and nonagricultural sites, with greater values observed at agricultural sites. In green frogs, EROD and MROD activities were measurable in both adult and juvenile frogs and were similar among sites. Median EROD activities ranged from 13 to 21 pmol/min/mg protein in adult male green frogs and from 5 to 13 pmol/min/mg protein in adult female green frogs. Juvenile frogs had greater EROD and MROD activities than adult frogs. Bullfrogs and leopard frogs had greater activities than did green frogs. Atrazine concentrations were significantly and negatively correlated with MROD activity in adult male green frogs (Spearman R = -0.800). LSI and EROD and MROD activities of adult female or juvenile green frogs were not significantly correlated with atrazine concentrations. These results suggest that atrazine does not appear to have a consistent association with EROD or MROD activities in wild-caught green frogs.
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Affiliation(s)
- M B Murphy
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, SAR, People's Republic of China.
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35
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Wong HL, Giesy JP, Lam PKS. Organochlorine insecticides in mudflats of Hong Kong, China. Arch Environ Contam Toxicol 2006; 50:153-65. [PMID: 16307213 DOI: 10.1007/s00244-005-7001-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Accepted: 05/14/2005] [Indexed: 05/05/2023]
Abstract
Organochlorine (OC) insecticides were measured in different environmental compartments (including seawater, sediment, and biota) at six sites within the Mai Po Marshes Nature Reserve (MPMNR) and at one site in A Chau (AC) in Hong Kong in June 2002 (wet season) and January 2003 (dry season). MPMNR is a Wetland of International Importance (Ramsar site) situated in the western part of Hong Kong, whereas AC is a relatively remote island in Starling Inlet on the eastern side of the New Territories of Hong Kong. Generally, concentrations of OC insecticides in water, sediment, and biota were greater at MPMNR than at AC. Hexachlorobenzene, dichloro-diphenyl-trichloroethane, and hexachlorocyclohexanes were detected in all samples collected from MPMNR. Preliminary risk assessments were performed by comparing the measured concentrations of OCs in different environmental compartments with the corresponding guidelines promulgated by various environmental protection authorities. Concentrations of some OCs in sediments from certain locations in MPMNR were consistently greater than their corresponding sediment guideline values. These results suggest that the sediment OC concentrations in the sediments of MPMNR might pose a risk to aquatic organisms. Despite this, concentrations of OCs in biota samples were much lower than the relevant guideline values promulgated by government agencies to protect the health of human consumers. It is postulated that the management practices adopted at MPMNR have been effective in limiting the bioaccumulation window (duration) for OCs. This situation may have been aided by a frequent exchange of water between the tidal shrimp ponds at MPMNR and the open sea, again attributable to management practices. The low-cost maintenance practices adopted at MPMNR may potentially be applicable to wetlands in other southeastern Asian countries, thus allowing sustainable fishery production and wildlife conservation.
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Affiliation(s)
- H L Wong
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
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36
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Fung CN, Zheng GJ, Connell DW, Zhang X, Wong HL, Giesy JP, Fang Z, Lam PKS. Risks posed by trace organic contaminants in coastal sediments in the Pearl River Delta, China. Mar Pollut Bull 2005; 50:1036-49. [PMID: 16199239 DOI: 10.1016/j.marpolbul.2005.02.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/11/2005] [Indexed: 05/04/2023]
Abstract
Local marine environments in China's Pearl River Delta (PRD), the most rapidly developing region in one of the world's fastest growing economies, have been experiencing significant environmental stress during the past decades. This investigation was conducted to determine the status and trends of persistence organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and dioxin-related compounds in marine sediments collected from sixteen coastal stations in the Pearl River Delta (PRD) in March 2003. Elevated concentrations of PAHs (94-4300 ng/g), PCBs (6.0-290 ng/g), PHCs (14-150 microg/g), and DDTs (1.4-600 ng/g) were detected in sediment samples. In addition, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like activities in the sediment samples were estimated to range from 0.3 to 440 pg TCDD-EQ/g. Sediments collected from Xiashan contained the greatest concentrations of trace organic contaminations amongst all the sampling stations in the present study. The degree of trace organic contamination was, in general, more severe at stations situated along the west shores of the PRD than their counterparts in the east. A preliminary assessment was performed to examine the probable risks to the marine ecosystem due to POPs. The results showed that OC pesticide contamination in the PRD was particularly serious and might pose a threat to the health of the marine inhabitants.
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Affiliation(s)
- C N Fung
- Department of Biology and Chemistry, Center for Coastal Pollution and Conservation, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong
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37
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Jiang QT, Lee TKM, Chen K, Wong HL, Zheng JS, Giesy JP, Lo KKW, Yamashita N, Lam PKS. Human health risk assessment of organochlorines associated with fish consumption in a coastal city in China. Environ Pollut 2005; 136:155-65. [PMID: 15809117 DOI: 10.1016/j.envpol.2004.09.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2004] [Accepted: 09/17/2004] [Indexed: 05/20/2023]
Abstract
Food consumption is an important route of human exposure to organochlorines (OCs). In order to assess the potential health risks associated with these contaminants due to fish consumption, five species of fish were collected from a local market in Zhoushan City, an island in the East China Sea. Dioxin-like compounds, such as polychlorinated dibenzo-p-dioxins/ dibenzofurans, in the fish samples were screened by H4IIE-luc cell bioassay, and the concentrations of specific organochlorines were measured by gas chromatograph-electron capture detector (GC-ECD). The bioassay results indicated that concentrations of dioxin-like compounds in the fish samples were below detection limit (0.64 pg/mL). The concentrations of OC pesticides and PCBs ranged from 0.67 to 13 and 0.24 to 1.4 ng/g wet wt., respectively. Significantly, concentrations of p,p'-DDE in fish meat were comparatively high (average 3.9 ng/g wet wt.) compared with the other OC pesticides. The daily fish consumption, based on a dietary survey conducted among 160 local healthy residents, was determined to be 105 g/person. The relevant cancer benchmark concentrations of HCB, dieldrin, chlordane, DDTs and PCBs were 0.36, 0.04, 1.6, 1.7, and 0.29 ng/kg per day, respectively, based on the local diet. The hazard ratios (HRs), based on non-cancer endpoints were all less than 1.0, while the HRs based on cancer were greater than 1.0 for certain contaminants based on the 95th centile concentration in fish tissue.
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Affiliation(s)
- Q T Jiang
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
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38
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Wong HL, Giesy JP, Siu WHL, Lam PKS. Estrogenic and dioxin-like activities and cytotoxicity of sediments and biota from Hong Kong mudflats. Arch Environ Contam Toxicol 2005; 48:575-86. [PMID: 15886900 DOI: 10.1007/s00244-004-0166-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Accepted: 10/19/2004] [Indexed: 05/02/2023]
Abstract
Persistent organic pollutants, such as organochlorine insecticides and polychlorinated biphenyls (PCBs), were measured in several environmental matrices including aerial deposition, seawater, sediment, and biota in two important coastal wetlands of Hong Kong, China. Specifically, samples were collected from within the Mai Po Marshes Nature Reserve (Mai Po), an internationally acclaimed wetland situated in the northwestern part of the New Territories of Hong Kong, and A Chau in Starling Inlet, a relatively remote island on the eastern side of Hong Kong. Hexachlorobenzene, dichlorodiphenyltrichloroethanes, and hexachlorocyclohexanes were detected in all samples collected from Mai Po. Environmental endocrine disruptors (including dioxin-like compounds and estrogenic chemicals), measured by the use of cell-based chemical activated luciferase expression assays, were found to occur at concentrations that might pose a risk to the ecologic systems in Mai Po. Dioxin-like PCBs were detected at small concentrations in some of the samples. Concentrations of 2,3,7,8 tetrachlorodibenzo-p-dioxin equivalents (TEQs) were primarily related to the relatively great concentrations (>100 ng/g dry weight) of high molecular-weight polycyclic aromatic hydrocarbons in sediments, whereas the relative proportion of TEQs contributed by nonortho-substituted PCBs was small. Polar compounds primarily contributed estrogen equivalents, which were measured in sediments. Significant concentrations of cytotoxic compounds were detected in fish samples collected from the Mai Po but not in fish collected from A Chau.
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Affiliation(s)
- H L Wong
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon
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39
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Ng PC, Wong HL, Lyon DJ, So KW, Liu F, Lam RKY, Wong E, Cheng AFB, Fok TF. Combined use of alcohol hand rub and gloves reduces the incidence of late onset infection in very low birthweight infants. Arch Dis Child Fetal Neonatal Ed 2004; 89:F336-40. [PMID: 15210670 PMCID: PMC1721714 DOI: 10.1136/adc.2003.031104] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To assess the incidence of late onset (> 72 hours) infection and necrotising enterocolitis (NEC) in very low birthweight (VLBW) infants in two 36 month periods using two hand hygiene protocols: conventional handwashing (HW; first 36 month period); an alcohol hand rub and gloves technique (HR; second 36 month period). METHOD VLBW infants admitted to the neonatal intensive care unit during the period December 1993-November 1999 were eligible. A new hand hygiene protocol using alcohol handrub and gloves was introduced in December 1996. Each patient's case record was reviewed retrospectively by two independent investigators using a standard data collection form. The incidence of NEC and systemic infections, including bacterial or fungal septicaemia, meningitis, and peritonitis, in the two periods were compared. RESULTS The HW and HR groups contained 161 and 176 VLBW infants respectively. The incidence of late onset systemic infection decreased from 13.5 to 4.8 episodes (including NEC)/1000 patient days after introduction of the HR regimen, representing a 2.8-fold reduction. Similarly, the incidence of Gram positive, Gram negative, and fungal infections decreased 2.5-fold, 2.6-fold, and 7-fold respectively. There was also a significant reduction in the incidence of NEC in the HR group (p < 0.0001). Subgroup analysis revealed that the incidence of methicillin resistant Staphylococcus aureus (MRSA) septicaemia was significantly decreased in the second 36 month period (p = 0.048). The clinical data suggest that infants in the HW group had significantly earlier onset of sepsis (p < 0.05) and required oxygen supplementation for longer (p < 0.05) than those in the HR group. Significantly more VLBW infants were discharged from the neonatal intensive care unit without ever being infected (p < 0.0001), and also significantly fewer infants had more than one episode of infection in the HR group (p < 0.0001). CONCLUSION The introduction of the HR protocol was associated with a 2.8-fold reduction in the incidence of late onset systemic infection, and also a significant decrease in the incidence of MRSA septicaemia and NEC in VLBW infants. This decrease in infection rate was maintained throughout the second 36 month period.
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Affiliation(s)
- P C Ng
- Level 6, Clinical Sciences Building, Prince of Wales Hospital, Shatin, NT, Hong Kong.
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Wong HL, Sakamoto T, Kawasaki T, Umemura K, Shimamoto K. Down-regulation of metallothionein, a reactive oxygen scavenger, by the small GTPase OsRac1 in rice. Plant Physiol 2004; 135:1447-56. [PMID: 15220467 PMCID: PMC519061 DOI: 10.1104/pp.103.036384] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Metallothioneins are small, ubiquitous Cys-rich proteins known to be involved in reactive oxygen species (ROS) scavenging and metal homeostasis. We found that the expression of a metallothionein gene (OsMT2b) was synergically down-regulated by OsRac1 and rice (Oryza sativa) blast-derived elicitors. Transgenic plants overexpressing OsMT2b showed increased susceptibility to bacterial blight and blast fungus. OsMT2b-overexpressing cells showed reduced elicitor-induced hydrogen peroxide production. In contrast, homozygous OsMT2b::Tos17-inserted mutant and OsMT2b-RNAi-silenced transgenic cells showed significantly higher elicitor-induced hydrogen peroxide production than the wild-type cells. In vitro assay showed that recombinant OsMT2b protein possessed superoxide- and hydroxyl radical-scavenging activities. Taken together, these results showed that OsMT2b is an ROS scavenger and its expression is down-regulated by OsRac1, thus potentiating ROS, which function as signals in resistance response. The results suggest that OsRac1 plays a dual role as an inducer of ROS production and a suppressor of ROS scavenging.
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Affiliation(s)
- Hann Ling Wong
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara 630-0101, Japan
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Li HM, Zhuang ZH, Wang Q, Pang JCS, Wang XH, Wong HL, Feng HC, Jin DY, Ling MT, Wong YC, Eliopoulos AG, Young LS, Huang DP, Tsao SW. Epstein–Barr virus latent membrane protein 1 (LMP1) upregulates Id1 expression in nasopharyngeal epithelial cells. Oncogene 2004; 23:4488-94. [PMID: 15064751 DOI: 10.1038/sj.onc.1207580] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nasopharyngeal carcinoma is closely associated with Epstein-Barr virus (EBV) infection. The EBV-encoded LMP1 has cell transformation property. It suppresses cellular senescence and enhances cell survival in various cell types. Many of the downstream events of LMP1 expression are mediated through its ability to activate NF-kappaB. In this study, we report a novel function of LMP1 to induce Id1 expression in nasopharyngeal epithelial cells (NP69) and human embryonal kidney cells (HEK293). The Id1 is a basic helix-loop-helix (bHLH) protein and a negative transcriptional regulator of p16(INK4a). Expression of Id1 facilitates cellular immortalization and stimulates cell proliferation. With the combination of both specific chemical inhibitors and genetic inhibitors of cell signaling, we showed that induction of Id1 by LMP1 was dependent on its NF-kappaB activation domain at the carboxy-terminal region, CTAR1 and CTAR2. Induction of Id1 by LMP1 may facilitate clonal expansion of premalignant nasopharyngeal epithelial cells infected with EBV and may promote their malignant transformation.
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Affiliation(s)
- H M Li
- Department of Anatomy, The University of Hong Kong, 21 Sassoon Road, Hong Kong SAR, China
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Abstract
The effect of size and tissue parts as well as site locations on a suite of six anti-oxidative biochemical markers, viz. the enzyme degrading neural transmitters acetylcholinesterase (AChE), the Phase II transforming enzyme glutathione-S-transferase (GST), the anti-oxidative enzymes superoxide dismutase (SOD) and catalase (CAT), the lipid metabolite malondialdehyde (MDA) and the ratio of CAT/MDA, in the bivalve mollusc, Perna viridis, was studied. Field mussels were collected from the piers of University of Science and Technology (UST), Pak Sha Wan or Hebe Haven (PS) and Sai Kung (SK) in Port Shelter, Hong Kong. Statistically, ANOVA showed that the activity of all six biochemical markers were generally tissue dependent, size independent and location dependent. Tukey multi comparison test indicated that the biochemical activities fell into two groups, with SK the highest activity group in most cases. The significance of these findings in relation to long-term coastal water biomonitoring is discussed.
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Affiliation(s)
- P S Lau
- Institute for Environment and Sustainable Development, Hong Kong University of Science and Technology, Hong Kong.
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Siu WHL, Hung CLH, Wong HL, Richardson BJ, Lam PKS. Exposure and time dependent DNA strand breakage in hepatopancreas of green-lipped mussels (Perna viridis) exposed to Aroclor 1254, and mixtures of B[a]P and Aroclor 1254. Mar Pollut Bull 2003; 46:1285-1293. [PMID: 14550341 DOI: 10.1016/s0025-326x(03)00234-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Green-lipped mussels (Perna viridis) were exposed to Aroclor 1254 (0.5, 5 and 50 microgl(-1)) and a mixture of benzo[a]pyrene (B[a]P) and Aroclor 1254 (0.3+0.5 and 3+5 microgl(-1)) for 12 days. On day 0, 1, 3, 6 and 12, the levels of DNA strand breaks in the mussel hepatopancreas were monitored using an alkaline unwinding assay. The results were compared to the findings of a previous study in which the levels of DNA strand breakage in the same species were measured following exposure to various concentrations of B[a]P (0.3, 3 and 30 microgl(-1)). The results indicated that Aroclor 1254 at a concentration </=50 microgl(-1) did not cause any increase in DNA strand breaks while B[a]P at concentrations ranging from 0.3 to 3 microgl(-1) caused an increase in strand breaks after one day of exposure, followed by an apparent rapid recovery. In contrast, exposure to 30 microgl(-1) B[a]P caused no increase in DNA strand breaks over the exposure period. This was postulated to be due to an early elicitation of the DNA repair system by the relatively high exposure level of B[a]P. This hypothesis was tested in the present study, and the results suggest that exposure to the high B[a]P concentration might have elicited the defense mechanism within the mussels, resulting in no observed increase in DNA strand breaks. An increase in strand breaks was, however, evident when the mussels were exposed to lower B[a]P levels. The levels of DNA strand breaks were correlated with the body burden of B[a]P and Aroclor 1254 but no significant relationship was observed, possibly owing to the rapid metabolism of the toxicant and/or an effective DNA repair mechanism. As a result, DNA strand breakage in the hepatopancreas of green-lipped mussels may not be a suitable biomarker of exposure to the above toxicants in the marine environment. Our findings also suggest that it would be instructive to investigate (1) the role of DNA repair enzymes in the exposed mussels; and (2) the correlation between the activity of these enzymes and the body burden of specific toxicants.
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Affiliation(s)
- W H L Siu
- Centre for Coastal Pollution and Conservation, Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong
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Takahashi A, Kawasaki T, Wong HL, Suharsono U, Hirano H, Shimamoto K. Hyperphosphorylation of a mitochondrial protein, prohibitin, is induced by calyculin A in a rice lesion-mimic mutant cdr1. Plant Physiol 2003; 132:1861-9. [PMID: 12913143 PMCID: PMC181272 DOI: 10.1104/pp.103.021733] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2003] [Revised: 03/15/2003] [Accepted: 04/24/2003] [Indexed: 05/18/2023]
Abstract
The rice (Oryza sativa) lesion-mimic mutants, cell death and resistance (cdr), show spontaneous cell death on the entire leaf and exhibited significant resistance to the rice blast fungus. Our previous studies showed that CDR1 and CDR2 genes negatively regulated the phosphorylation steps leading to the activation of NADPH oxidase, which is associated with oxidative burst. To identify novel factors involved in the phosphorylation steps, the phosphorylation level of total proteins was compared between cdr mutants and wild type using two-dimensional gel electrophoresis. Here, we show that the phosphorylation level of four proteins in cdr1 was increased as compared with the wild type after calyculin A treatment. Partial amino acid sequences revealed that one of the four proteins is homologous to prohibitin (PHB), which has been shown to be associated with senescence and cell death and to function as a chaperone in the assembly of mitochondrial respiratory chain complex in yeast and mammals. Analysis of green fluorescent protein fusions indicated that rice PHB (OsPHB1) was targeted to mitochondria as found in yeast and mammals, suggesting a possibility that PHB is involved in defense response and/or programmed cell death through the mitochondrial function.
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Affiliation(s)
- Akira Takahashi
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, 630-0101, Japan
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Abstract
OBJECTIVE The purpose of this study was to assess the effectiveness of music therapy in decreasing anxiety in ventilator-dependent patients. DESIGN A crossover repeated measures design with random assignment was used. SETTING The intensive care unit of a university hospital in Hong Kong was used as the setting for this study. PATIENTS Twenty patients who were ventilator-dependent were recruited for the study. They were all Chinese with a mean age of 58.25 years (range, 19-84 y). Most (75%) were men. OUTCOME MEASURES Physiologic measures of anxiety assessed in this study were mean blood pressure and respiratory rate. An additional measure was the Chinese version of the Spielberger State-Trait Anxiety Inventory. INTERVENTION Patients were randomized to receive either 30 minutes of uninterrupted rest and then 30 minutes of music therapy or the music therapy first and then the uninterrupted rest period. Patients listened to relaxing music by using audiocassette players and headphones. Subjects selected the music of their choice from a selection including both Chinese and Western music. Subjects had physiologic measures taken immediately before the intervention (or rest period) and at 5-minute intervals throughout the intervention. The Chinese version of Spielberger's State-Trait Anxiety Inventory was completed before the intervention and immediately after the intervention. RESULTS Findings indicated that music therapy was more effective in decreasing state anxiety than was an uninterrupted rest period (P <.01). As measured by analysis of variance with repeated measures, blood pressure and respiratory rate showed no significant differences in the 2 conditions over time. However, significant differences were observed at the end of the intervention (after 30 minutes) between the 2 conditions, with music therapy being superior to the rest period. CONCLUSION Music therapy is an effective nursing intervention in decreasing anxiety in ventilator-dependent patients and its use should be incorporated into the care of mechanically ventilated patients. For the Chinese patients, culture and language were the predominant factors in their choice of music.
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Affiliation(s)
- H L Wong
- Intensive Care Unit, Prince of Wales Hospital, Hong Kong, China
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Fok TF, Gu JS, Lim CN, Ng PC, Wong HL, So KW. Oxygen consumption and resting energy expenditure during phototherapy in full term and preterm newborn infants. Arch Dis Child Fetal Neonatal Ed 2001; 85:F49-52. [PMID: 11420323 PMCID: PMC1721262 DOI: 10.1136/fn.85.1.f49] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To determine the effect of phototherapy on the oxygen consumption and resting energy expenditure of term and preterm newborn infants. METHODS A total of 202 infants (gestation 30-42 weeks; body weight 1270-4100 g) requiring phototherapy for the treatment of neonatal hyperbilirubinaemia were enrolled in a randomised crossover study. In random sequence, the oxygen consumption and resting energy expenditure were measured twice in each infant by indirect calorimetry, once at the end of six hours of continuous phototherapy and once after a control period of at least six hours without phototherapy. Anterior abdominal wall temperature was servocontrolled at 36.5 degrees C throughout the study. RESULTS At the end of six hours of continuous phototherapy, oxygen consumption (mean (SD): 6.21 (1.35) v 6.26 (1.51) ml/kg, p = 0.555) and resting energy expenditure (178.11 (37.62) v 180.37 (43.14) kJ/kg/24 h, p = 0.382) did not differ significantly from those measured after the control period. There were also no significant differences in heart rate, respiratory rate, or rectal temperature. Subgroup analysis of those of gestation < 37 weeks or < 34 weeks also showed no effect of phototherapy on either oxygen consumption or resting energy expenditure. CONCLUSION Phototherapy has no effect on the metabolic rate of thermally stable term or preterm infants.
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Affiliation(s)
- T F Fok
- Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong.
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Ono E, Wong HL, Kawasaki T, Hasegawa M, Kodama O, Shimamoto K. Essential role of the small GTPase Rac in disease resistance of rice. Proc Natl Acad Sci U S A 2001; 98:759-64. [PMID: 11149940 PMCID: PMC14661 DOI: 10.1073/pnas.98.2.759] [Citation(s) in RCA: 203] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Production of reactive oxygen intermediates (ROI) and a form of programmed cell death called hypersensitive response (HR) are often associated with disease resistance of plants. We have previously shown that the Rac homolog of rice, OsRac1, is a regulator of ROI production and cell death in rice. Here we show that the constitutively active OsRac1 (i) causes HR-like responses and greatly reduces disease lesions against a virulent race of the rice blast fungus; (ii) causes resistance against a virulent race of bacterial blight; and (iii) causes enhanced production of a phytoalexin and alters expression of defense-related genes. The dominant-negative OsRac1 suppresses elicitor-induced ROI production in transgenic cell cultures, and in plants suppresses the HR induced by the avirulent race of the fungus. Taken together, our findings strongly suggest that OsRac1 has a general role in disease resistance of rice.
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Affiliation(s)
- E Ono
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan
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Huang J, Wong HL, Zhou Y, Wu XY, Grad H, Komorowski R, Friedman S. In vitro studies and modeling of a controlled-release device for root canal therapy. J Control Release 2000; 67:293-307. [PMID: 10825562 DOI: 10.1016/s0168-3659(00)00225-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Endodontic disease is caused primarily by bacteria that interact with periradicular host tissues. Therefore, treatment of endodontic disease aims at the exclusion of bacteria from the root canal system. This work focused on in vitro studies and modeling of a controlled-release device for delivering antimicrobial agents in root canals. A cylindrical, needle-shaped device was prepared consisting of a matrix core and a polymer coating, loaded with 30-45% chlorhexidine (CHX). The composition of the core, a blend of water-permeable polymers, and the thickness of the coating were tailored to impart various release rates. A relatively steady release rate for over 40 days after an initial burst was achieved using a formulation for long-term release, which is desirable for establishing and maintaining the necessary therapeutic levels. Mathematical models were developed for both in vitro and in vivo drug release into a liquid of limited volume, taking into account a moving boundary of the dispersed drug and a time-dependent boundary condition. A concentration-dependent effective diffusion coefficient was used to count increased porosity as the solid drug had dissolved. The finite element method and computer programs were applied to solve the differential equations and predict the in vitro and in vivo release kinetics. The model prediction agreed well with the in vitro experimental data and provided guidance for designing the device for in vivo release in root canals. The result of in vitro antimicrobial tests, performed using a bovine tooth model, suggested that the device was effective in reducing growth of microbes.
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Affiliation(s)
- J Huang
- Faculty of Pharmacy, University of Toronto, M5S 2S2, Toronto, Canada
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Bern Z, De Freitas A, Wong HL. Coupling gravitons to matter. Phys Rev Lett 2000; 84:3531-3534. [PMID: 11019138 DOI: 10.1103/physrevlett.84.3531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/1999] [Indexed: 05/23/2023]
Abstract
Using relationships between open and closed strings, we present a construction of tree-level scattering amplitudes for gravitons minimally coupled to matter in terms of gauge theory partial amplitudes. In particular, we present examples of amplitudes with gravitons coupled to vectors or to a single fermion pair. We also present two examples with massive graviton exchange, as would arise in the presence of large compact dimensions. The gauge charges are represented by flavors of dynamical scalars or fermions. This also leads to an unconventional decomposition of color and kinematics in gauge theories.
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Affiliation(s)
- Z Bern
- Department of Physics and Astronomy, The University of California at Los Angeles, Los Angeles, California 90095-1547, USA
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Abstract
Amplified fragment length polymorphism (AFLP) markers were used in the characterization of eight cassava varieties. This nonradioactive AFLP system was customized in terms of the choice of restriction enzymes used and the selection of nucleotides added to the 3' end of primers. EcoRI/MseI and HindIII/MseI fragments generally gave monomorphic profiles while ApaI/TaqI fragments produced polymorphic profiles suggesting a genome with high G + C content. It was possible to identify the eight cassava varieties used in this study using CTG as selective bases at the TaqI primer. For cassava, the AFLP system provided a higher number of loci detected per run when compared to RAPD. The reliability accompanying AFLP analysis would thus make it suitable for the characterization of cassava varieties.
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Affiliation(s)
- H L Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore
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