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result(s) for
"Le, Tu Ngoc"
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miR2118-dependent U-rich phasiRNA production in rice anther wall development
2020
Reproduction-specific small RNAs are vital regulators of germline development in animals and plants. MicroRNA2118 (miR2118) is conserved in plants and induces the production of phased small interfering RNAs (phasiRNAs). To reveal the biological functions of miR2118, we describe here rice mutants with large deletions of the miR2118 cluster. Our results demonstrate that the loss of miR2118 causes severe male and female sterility in rice, associated with marked morphological and developmental abnormalities in somatic anther wall cells. Small RNA profiling reveals that miR2118-dependent 21-nucleotide (nt) phasiRNAs in the anther wall are U-rich, distinct from the phasiRNAs in germ cells. Furthermore, the miR2118-dependent biogenesis of 21-nt phasiRNAs may involve the Argonaute proteins OsAGO1b/OsAGO1d, which are abundant in anther wall cell layers. Our study highlights the site-specific differences of phasiRNAs between somatic anther wall and germ cells, and demonstrates the significance of miR2118/U-phasiRNA functions in anther wall development and rice reproduction.
MicroRNA2118 induces the production of phased small interfering RNAs (phaisRNAs) in plants. Here the authors show that rice miR2118 is required for both male and female fertility and supports the production of atypical U-rich 21 nt phasiRNAs that are abundant in anther walls.
Journal Article
Epigenetic regulation of spurious transcription initiation in Arabidopsis
2020
In plants, epigenetic regulation is critical for silencing transposons and maintaining proper gene expression. However, its impact on the genome-wide transcription initiation landscape remains elusive. By conducting a genome-wide analysis of transcription start sites (TSSs) using cap analysis of gene expression (CAGE) sequencing, we show that thousands of TSSs are exclusively activated in various epigenetic mutants of
Arabidopsis thaliana
and referred to as cryptic TSSs. Many have not been identified in previous studies, of which up to 65% are contributed by transposons. They possess similar genetic features to regular TSSs and their activation is strongly associated with the ectopic recruitment of RNAPII machinery. The activation of cryptic TSSs significantly alters transcription of nearby TSSs, including those of genes important for development and stress responses. Our study, therefore, sheds light on the role of epigenetic regulation in maintaining proper gene functions in plants by suppressing transcription from cryptic TSSs.
Epigenetic regulation can silence transposons and maintain gene expression. Here the authors survey
Arabidopsis
mutants defective in epigenetic regulation and show ectopic activation of thousands of cryptic TSSs and altered expression of nearby genes demonstrating the importance of suppressing spurious transcription.
Journal Article
Climate change adaptation in coastal cities of developing countries: characterizing types of vulnerability and adaptation options
2020
Facing the increasingly adverse impacts of climate change, many coastal cities in developing and least-developed countries have shaped their climate adaptation plan. This study aims to unpack the state-of-the-art municipal adaptation planning in developing countries. The paper seeks to understand the types of vulnerability and explore planned adaptation options through a content analysis of adaptation planning documents in 45 selected coastal cities in developing countries. The result shows the complexity of vulnerabilities that are not only climate change impacts, but more importantly, the socio-economic sensitivity, the insufficient infrastructure system, and limited adaptive capacity. Adaptation responses, correspondingly, address primarily current vulnerabilities rather than future climate change impacts. Local climate change adaptation in developing countries, therefore, cannot separate from socio-economic development and capacity enhancement. A coordination mechanism for inter-policy is necessary to manage the trade-offs between multiple priorities.
Journal Article
Transcriptional regulation of genes bearing intronic heterochromatin in the rice genome
by
Tu, Le Ngoc
,
Saze, Hidetoshi
,
Shimajiri, Yasuka
in
Biodiversity
,
Biology and Life Sciences
,
Chromatin
2020
Intronic regions of eukaryotic genomes accumulate many Transposable Elements (TEs). Intronic TEs often trigger the formation of transcriptionally repressive heterochromatin, even within transcription-permissive chromatin environments. Although TE-bearing introns are widely observed in eukaryotic genomes, their epigenetic states, impacts on gene regulation and function, and their contributions to genetic diversity and evolution, remain poorly understood. In this study, we investigated the genome-wide distribution of intronic TEs and their epigenetic states in the Oryza sativa genome, where TEs comprise 35% of the genome. We found that over 10% of rice genes contain intronic heterochromatin, most of which are associated with TEs and repetitive sequences. These heterochromatic introns are longer and highly enriched in promoter-proximal positions. On the other hand, introns also accumulate hypomethylated short TEs. Genes with heterochromatic introns are implicated in various biological functions. Transcription of genes bearing intronic heterochromatin is regulated by an epigenetic mechanism involving the conserved factor OsIBM2, mutation of which results in severe developmental and reproductive defects. Furthermore, we found that heterochromatic introns evolve rapidly compared to non-heterochromatic introns. Our study demonstrates that heterochromatin is a common epigenetic feature associated with actively transcribed genes in the rice genome.
Journal Article
Resistance Mutation Patterns among HIV-1-Infected Children and Features of the Program for Prevention of Mother-to-Child Transmission in Vietnam’s Central Highlands and Southern Regions, 2017–2021
by
Davydenko, Vladimir S.
,
Tran, Ton
,
Tuong Vi, Nguyen
in
Acquired immune deficiency syndrome
,
AIDS
,
Analysis
2024
The Vietnam Ministry of Health (MOH) has intensified efforts in its aim to eliminate AIDS by 2030. Expanding the program for prevention of mother-to-child transmission (PMTCT) is a significant step towards achieving this goal. However, there are still HIV-exposed children who do not have access to PMTCT services, and some who have participated in the program but still contracted HIV. This study focused on assessing the prevalence and profile of HIV mutations among children under 18 months of age who had recently tested positive for HIV, while gaining insights into the implementation of early infant diagnostic (EID) tests. Between 2017 and 2021, 3.43% of 5854 collected dry blood spot (DBS) specimens from Vietnam’s Central and Southern regions showed positive EID results. This study identified a high prevalence of resistance mutations in children, totaling 62.9% (95% CI: 53.5–72.3). The highest prevalence of mutations was observed for NNRTIs, with 57.1% (95% CI: 47.5–66.8). Common mutations included Y181C and K103N (NNRTI resistance), M184I/V (NRTI resistance), and no major mutations for PI. The percentage of children with any resistance mutation was significantly higher among those who received PMTCT interventions (69.2%; 95% CI: 50.5–92.6%) compared with those without PMTCT (45.0%; 95% CI: 26.7–71.1%) with χ2 = 6.06, p = 0.0138, and OR = 2.75 (95% CI: 1.13–6.74). Mutation profiles revealed that polymorphic mutations could be present regardless of whether PMTCT interventions were implemented or not. However, non-polymorphic drug resistance mutations were predominantly observed in children who received PMTCT measures. Regarding PMTCT program characteristics, this study highlights the issue of late access to HIV testing for both mothers and their infected children. Statistical differences were observed between PMTCT and non-PMTCT children. The proportion of late detection of HIV infection and breastfeeding rates were significantly higher among non-PMTCT children (p < 0.05). Comparative analysis between children with low viral load (≤200 copies/mL) and high viral load (>200 copies/mL) showed significant differences between the mothers’ current ART regimens (p = 0.029) and the ARV prophylaxis regimen for children (p = 0.016). These findings emphasize the need for comprehensive surveillance to assess the effectiveness of the PMTCT program, including potential transmission of HIV drug-resistance mutations from mothers to children in Vietnam.
Journal Article
In the interest of public safety: rapid response to the COVID-19 epidemic in Vietnam
by
Vu, Long Ngoc
,
Tran, Quang Dai
,
Nguyen, Thinh Viet
in
Border stations
,
Boundaries
,
Communicable Disease Control
2021
We describe the status of the COVID-19 epidemic in Vietnam, major response successes, factors that prompted implementation of certain public health actions, and the impact of these actions. In addition, information for three case studies is reported, with crucial learnings to inform future response. Findings from this study suggest that as early as 20 January 2020, Vietnam held a national risk assessment, established a national COVID-19 Response Plan and Technical Treatment and Care Guidelines, and prepared public health laboratories to accurately diagnose cases and hospitals to effectively treat patients. The first COVID-19 case was detected on 23 January. As of 30 September, there had been three waves of the COVID-19 epidemic totalling 1095 cases, and resulting in 35 deaths all among people with underlying health conditions. Evidence of potential transmission of SARS-CoV-2 from a commercial passenger flight inbound to Vietnam was reported. This study also highlights the importance of early technical preparedness, strong political commitment, multisectoral and multilevel efforts, increased resourcing and coordination towards an effective COVID-19 response. Controlling outbreaks in settings, such as crowded public places (bars and hospitals), within certain villages and over cities, required early detection, aggressive trace-test-quarantine efforts, a geographically extensive lockdown area and an adoption of several non-pharmaceutical interventions. Many low-income and middle-income countries have experienced their second or third wave of the COVID-19 epidemic, and they can learn from Vietnam’s response across the three epidemic waves. Swift governmental action, strict border control measures, effective communication of health promotion measures, widespread community engagement, expanded testing capacity and effective social measures to slow the spread of SARS-CoV-2, are highly important in these locations.
Journal Article
Outbreak of Sexually Transmitted Nongroupable Neisseria meningitidis –Associated Urethritis, Vietnam
by
Nguyen, Hao Trong
,
Pham, Nhi Thi Uyen
,
Bui, Ha Manh
in
Antibiotics
,
Antimicrobial agents
,
antimicrobial resistance
2023
We report on an outbreak of nongroupable Neisseria meningitidis–associated urethritis, primarily among men who have sex with men in southern Vietnam. Nearly 50% of N. meningitidis isolates were resistant to ciprofloxacin. This emerging pathogen should be considered in the differential diagnosis and management of urethritis.
Journal Article
Clinical prognostic models for severe dengue: a systematic review protocol
by
Le Ngoc, Tu
,
Phung Khanh, Lam
,
Dao Phuoc, Thang
in
Bibliographic data bases
,
Classification
,
Dengue fever
2019
Background:
Dengue is a common mosquito-borne, with high morbidity rates recorded in the annual. Dengue contributes to a major disease burden in many tropical countries. This demonstrates the urgent need in developing effective approaches to identify severe cases early. For this purpose, many multivariable prognostic models using multiple prognostic variables were developed to predict the risk of progression to severe outcomes. The aim of the planned systematic review is to identify and describe the existing clinical multivariable prognostic models for severe dengue as well as examine the possibility of combining them. These findings will suggest directions for further research of this field.
Methods:
This protocol has followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta – Analyses Protocol (PRISMA-P). We will conduct a comprehensive search of Pubmed, Embase, and Web of Science. Eligibility criteria include being published in peer-review journals, focusing on human subjects and developing the multivariable prognostic model for severe dengue, without any restriction on language, location and period of publication, and study design. The reference list will be captured and removed from duplications. We will use the Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS) checklist to extract data and Prediction study risk of bias assessment tool (PROBAST) to assess the study quality.
Discussion:
This systematic review will describe the existing prediction models, summarize the current status of prognostic research on dengue, and report the possibility to combine the models to optimize the power of each paradigm.
PROSPERO registration
:
CRD42018102907
Journal Article
TiO2 Nanotubes with Different Ag Loading to Enhance Visible-Light Photocatalytic Activity
2017
An improved photocatalytic activity of semiconductor materials using incorporation of the noble metals such as Ag, Au, and Pt is a promising technology. In this study, Ag nanoparticle-TiO2 nanotube structures (Ag-TNTs) have been investigated as a photocatalyst in different irradiation conditions using different characterization techniques. The results indicate that Ag nanoparticles dispersed uniformly on the TNTs’ surface without any change in TNTs’ morphology. In addition, Ag-TNTs exhibited lower photoactivity than the TNTs under UV irradiation. In contrast, Ag-TNTs increased the photoactivity in comparison with TNTs and the photocatalytic performance under sunlight irradiation. These phenomena could be contributed to the appearance of Ag nanoparticles on the nanotube surface.
Journal Article
Impact of CuS counter electrode calcination temperature on quantum dot sensitized solar cell performance
2023
INTRODUCTION Inorganic semiconductor quantum dots (QDs), which have an extremely high capacity to synthesize electrons for use in solar cells, have recently gained notoriety as such materials. When we do current and potential density measurements, electrochemical impedance measurements, and employ Na2S203.5H20 and Cu(N03)2 bought from Sigma's firm, Germany, we use colloidal silver as the route of the front and rear of the solar cell. [...]it was stored for preparation of quantum dot - sensitized solar cell. [...]we first need to ascertain the structure of CuS in order to use it as electrodes.
Journal Article