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"Lee, Wei-Chin"
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Argonaute 5 family proteins play crucial roles in the defence against Cymbidium mosaic virus and Odontoglossum ringspot virus in Phalaenopsis aphrodite subsp. formosana
The orchid industry faces severe threats from diseases caused by viruses. Argonaute proteins (AGOs) have been shown to be the major components in the antiviral defence systems through RNA silencing in many model plants. However, the roles of AGOs in orchids against viral infections have not been analysed comprehensively. In this study, Phalaenopsis aphrodite subsp. formosana was chosen as the representative to analyse the AGOs (PaAGOs) involved in the defence against two major viruses of orchids, Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV). A total of 11 PaAGOs were identified from the expression profile analyses of these PaAGOs in P. aphrodite subsp. formosana singly or doubly infected with CymMV and/or ORSV. PaAGO5b was found to be the only one highly induced. Results from overexpression of individual PaAGO5 family genes revealed that PaAGO5a and PaAGO5b play central roles in the antiviral defence mechanisms of P. aphrodite subsp. formosana. Furthermore, a virus‐induced gene silencing vector based on Foxtail mosaic virus was developed to corroborate the function of PaAGO5s. The results confirmed their importance in the defences against CymMV and ORSV. Our findings may provide useful information for the breeding of traits for resistance or tolerance to CymMV or ORSV infections in Phalaenopsis orchids. Phalaenopsis aphrodite subsp. formosana harbours 11 argonaute genes (PaAGOs), among which PaAGO5b plays a crucial role in the antiviral defence mechanisms against Cymbidium mosaic virus and Odontoglossum ringspot virus.
Journal Article
Stable Display of Artificially Long Foreign Antigens on Chimeric Bamboo mosaic virus Particles
Plant viruses can be genetically modified to generate chimeric virus particles (CVPs) carrying heterologous peptides fused on the surface of coat protein (CP) subunits as vaccine candidates. However, some factors may be especially significant in determining the properties of chimeras. In this study, peptides from various sources and of various lengths were inserted into the Bamboo mosaic virus-based (BaMV) vector CP N-terminus to examine the chimeras infecting and accumulating in plants. Interestingly, it was found that the two different strains Foot-and-mouth disease virus (FMDV) VP1 antigens with flexible linker peptides (77 or 82 amino acids) were directly expressed on the BaMV CP, and the chimeric particles self-assembled and continued to express FMDV antigens. The chimeric CP, when directly fused with a large foreign protein (117 amino acids), can self-fold into incomplete virus particles or disks. The physicochemical properties of heterologus peptides N-terminus, complex strand structures of heterologus peptides C-terminus and different flexible linker peptides, can affect the chimera accumulation. Based on these findings, using plant virus-based chimeras to express foreign proteins can increase their length limitations, and engineered plant-made CVP-based vaccines have increasing potential for further development as novel vaccines.
Journal Article
TGF-βI Regulates Cell Migration through Pluripotent Transcription Factor OCT4 in Endometriosis
Transforming growth factor (TGF-β)/TGF-β receptor signal is known to promote cell migration. Up-regulation of TGF-β in serum/peritoneal fluid and increased levels of pluripotent transcription factor OCT4 in endometriotic tissues are frequently observed in patients with endometriosis. However, the mechanisms underlying how TGF-β/TGF-β receptor and OCT4 affect endometriotic cell migration still remain largely unknown. Therefore, endometriotic tissue with high cell migratory capacity were collected from patients with adenomyotic myometrium (n = 23) and chocolate cyst (n = 24); and endometrial tissue with low cell migratory capacity in normal endometrium or hyperplastic endometrium (n = 8) were collected as the controls. We found the mRNA levels of TGF-β receptor I (TGF-β RI) and OCT4 were significantly higher in the high-migratory ectopic endometriotic tissues than those of the low-migratory normal or hyperplastic endometrium. Positive correlations between TGF-β RI and OCT4, and either TGF-β RI or OCT4 with migration-related genes (SNAIL, SLUG and TWIST) regarding the mRNA levels were observed in human endometriotic tissues. TGF-βI dose-dependently increased the gene and protein levels of OCT4, SNAIL and N-Cadherin (N-CAD) and silencing of endogenous OCT4 significantly suppressed the TGF-βI-induced expressions of N-CAD and SNAIL in primary human endometriotic stromal cells and human endometrial carcinoma cell lines RL95-2 and HEC1A. Furthermore, TGF-βI significantly increased the migration ability of endometriotic cells and silencing of OCT4 dramatically suppressed the TGF-βI-induced cell migration activity evidenced by wound-closure assay, transwell assay, and confocal image of F-actin cellular distribution. In conclusion, the present findings demonstrate that the niche TGF-β plays a critical role in initiating expressions of pluripotent transcription factor OCT4 which may contribute to the ectopic endometrial growth by stimulating endometrial cell migration. These findings would be useful for developing therapeutic strategies targeting TGF-β-OCT4 signaling to prevent endometriosis in the future.
Journal Article
First Report of Distinct Bamboo mosaic virus (BaMV) Isolates Infecting Bambusa funghomii in Vietnam and the Identification of a Highly Variable Region in the BaMV Genome
New isolates of the Bamboo mosaic virus (BaMV) were identified in Bambusa funghomii bamboo in Vietnam. Sequence analyses revealed that the Vietnam isolates are distinct from all known BaMV strains, sharing the highest sequence identities (about 77%) with the Yoshi isolates reported in California, USA. Unique satellite RNAs were also found to be associated with the BaMV Vietnam isolates. A possible recombination event was detected in the genome of BaMV-VN2. A highly variable region was identified in the ORF1 gene, in between the methyl transferase domain and helicase domain. These results revealed the presence of unique BaMV isolates in an additional bamboo species in one more country, Vietnam, and provided evidence in support of the possible involvement of environmental or host factors in the diversification and evolution of BaMV.
Journal Article
Coping with COVID-19: The Resilience and Transformation of Community-Based Tourism in Brunei Darussalam
The COVID-19 pandemic heavily impacted the travel and tourism industry, economies, livelihoods, public services, and opportunities globally. This is also observed in the small country of Brunei. As one of the few countries that have successfully mitigated COVID-19 transmissions, Brunei is slowly rebuilding its tourism industry through its community-based tourism (CBT). Following Sharma et al.’s resilience-based framework for reviving the tourism industry post-COVID-19 established in 2021, this study incorporates responses from semi-structured interviews with 16 local CBT owners on the challenges, the management, and the CBT initiatives during the height of the pandemic until today. These initiatives include diversifying more tour packages and utilising local resources and products. Despite the lockdown imposed by the government, which suspended businesses and restricted all travelling, local CBT operations flourished, generated more income for the owners, and created job opportunities for the community. Such efforts have caused the public to appreciate local cultures, the environment, and ultimately increase CBT experiences in the country. While shedding light on Brunei’s unique management of its tourism industry during the pandemic, this paper also demonstrates theoretical and conceptual contributions to the recent literature of resilient and transformational tourism and provide suggestions on how to manage CBT operations during these challenging times.
Journal Article
The new ecotourists of the 21st century: Brunei as a case study
Literature often describes the archetypical ecotourists as well-educated, and financially secure, coming from the \"Western\" Baby Boomer with strong convictions on the need for the conservation of nature and indigenous cultures. Today, traveling is made affordable for the mass coming from diverse nationalities, particularly of the younger generation, who are eager to experience disappearing cultures and nature. Although they appear to share traits of the ecotourists, are they truly the younger generations of ecotourists or do they seek out similar destination sites but for different reasons? Our research is the first attempt to answer this question. The paper aims to redefine the archetypical ecotourists in a market dominated by generations X, Y, and Z. The study involved survey questionnaires administered to 237 respondents living in Brunei coming from multiple generations comparing their attitudes, travel motivations, interests, and behaviour. A stratified-convenience sampling method was used to distribute the questionnaire to capture equal numbers of respondents in the three different generation groups. The data reveals some degree of incongruency between the younger generations of ecotourists and of the old archetypes. We found that the new ecotourists deviate in ideology and value. The new ecotourists are more inclined towards hedonism, social approval and popular culture. The differences in archetype have implications for tourism planning in general, and ecotourism in particular.
Journal Article
Antioxidant effects of black rice extract through the induction of superoxide dismutase and catalase activities
Our ex vivo study revealed that BRE had significantly stronger ability to inhibit LDL oxidation than white rice extract (WRE). The purpose of this study was to investigate whether black rice extract (BRE) supplementation might ameliorate oxidative stress and enhance antioxidant enzyme activities in HepG2 cells and in C57BL/6 mice. In the cellular study, superoxide anions (O2.−) and reactive oxygen species (ROS) in the BRE group were significantly suppressed. The BRE group also showed significant increases in superoxide dismutase (SOD) and catalase (CAT) activities by 161.6% and 73.4%, respectively. The major components responsible for the free‐radical‐scavenging and antioxidative properties might be cyanidin−3‐O‐glucoside chloride and peonidin‐3‐O‐glucuside chloride. In the animal study, male C57BL/6 mice were divided into three groups (control, BRE, and WRE). Plasma HDL‐cholesterol was significantly higher, and thiobarbituric, acid‐reactive substances were significantly lower in the BRE group, whereas plasma levels of total cholesterol and triglyceride were not affected by BRE supplementation. Increased hepatic SOD and CAT activities were observed in BRE‐treated mice as compared to the control mice. However, no changes were detected for the protein expression of antioxidant enzymes by Western blot analysis. Our data suggest that antioxidative effects exerted by BRE are mediated through decreases in free‐radical generation as well as increases in SOD and CAT activities both in vitro and in vivo.
Journal Article
Plasma Haptoglobin Concentrations Are Elevated in Patients with Coronary Artery Disease
Inflammation underlies the development and progression of coronary artery plaques. Haptoglobin (Hp) is an acute phase protein, the synthesis of which is increased during inflammation. The aim of this study was to investigate plasma Hp concentrations and phenotype in patients with coronary artery disease (CAD). We recruited 359 patients with fixed luminal stenosis ≥50% in at least one coronary artery (CAD group) and 83 patients with luminal stenosis ≤40%, normal ejection fraction, and normal regional wall motion (control group). Plasma Hp concentrations were measured using a phenotype-specific enzyme-linked immunosorbent assay. Hp phenotype was determined by native polyacrylamide gel electrophoresis. Plasma lipid concentrations were measured. Plasma Hp concentrations were significantly higher in the CAD compared with the control group (262.4±144.2 vs 176.0±86.7 ng/mL, P<0.001); however, there was no between group difference in the distribution of Hp phenotype (1-1 = 7.5% vs 7.2%; 2-1 = 40.4% vs 42.2%; 2-2 = 52.1% vs 50.6%). Stepwise multivariate logistic regression revealed that high Hp concentrations (odds ratio [OR] = 5.865), male sex (OR = 3.689), hypertension (OR = 2.632), diabetes mellitus (OR = 3.300), and low-density lipoprotein concentrations (OR = 1.480) were independently associated with CAD (all P<0.05). Hp phenotype was not associated with CAD. Plasma Hp concentrations were significantly correlated with the severity of luminal stenosis (r = 0.236, P<0.001). Our findings suggest that plasma Hp concentrations may be elevated in patients with CAD. There does not appear to be any relationship between Hp phenotype and CAD.
Journal Article