Publications by authors named "Nguyen Thanh Trung"

29 Publications

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Resequencing of 672 Native Rice Accessions to Explore Genetic Diversity and Trait Associations in Vietnam.

Rice (N Y) 2021 Jun 10;14(1):52. Epub 2021 Jun 10.

Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ, UK.

Background: Vietnam possesses a vast diversity of rice landraces due to its geographical situation, latitudinal range, and a variety of ecosystems. This genetic diversity constitutes a highly valuable resource at a time when the highest rice production areas in the low-lying Mekong and Red River Deltas are enduring increasing threats from climate changes, particularly in rainfall and temperature patterns.

Results: We analysed 672 Vietnamese rice genomes, 616 newly sequenced, that encompass the range of rice varieties grown in the diverse ecosystems found throughout Vietnam. We described four Japonica and five Indica subpopulations within Vietnam likely adapted to the region of origin. We compared the population structure and genetic diversity of these Vietnamese rice genomes to the 3000 genomes of Asian cultivated rice. The named Indica-5 (I5) subpopulation was expanded in Vietnam and contained lowland Indica accessions, which had very low shared ancestry with accessions from any other subpopulation and were previously overlooked as admixtures. We scored phenotypic measurements for nineteen traits and identified 453 unique genotype-phenotype significant associations comprising twenty-one QTLs (quantitative trait loci). The strongest associations were observed for grain size traits, while weaker associations were observed for a range of characteristics, including panicle length, heading date and leaf width.

Conclusions: We showed how the rice diversity within Vietnam relates to the wider Asian rice diversity by using a number of approaches to provide a clear picture of the novel diversity present within Vietnam, mainly around the Indica-5 subpopulation. Our results highlight differences in genome composition and trait associations among traditional Vietnamese rice accessions, which are likely the product of adaption to multiple environmental conditions and regional preferences in a very diverse country. Our results highlighted traits and their associated genomic regions that are a potential source of novel loci and alleles to breed a new generation of low input sustainable and climate resilient rice.
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http://dx.doi.org/10.1186/s12284-021-00481-0DOI Listing
June 2021

Polycyclic aromatic hydrocarbons in airborne particulate matter samples from Hanoi, Vietnam: Particle size distribution, aryl hydrocarbon ligand receptor activity, and implication for cancer risk assessment.

Chemosphere 2021 Apr 30;280:130720. Epub 2021 Apr 30.

Centre for Environmental Technology and Sustainable Development (CETASD), University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Hanoi, 11400, Viet Nam. Electronic address:

Concentrations and profiles of unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) were analyzed in airborne particulate matter (PM) samples collected from high-traffic roads in Hanoi urban area. Levels of PAHs and Me-PAHs ranged from 210 to 660 (average 420) ng/m in total PM, and these pollutants were mainly associated with fine particles (PM) rather than coarser ones (PM and PM). Proportions of high-molecular-weight compounds (i.e., 5- and 6-ring) increased with decreasing particle size. Benzo[b+k]fluoranthene, indeno[1,2,3-cd]pyrene, and benzo[ghi]perylene were the most predominant compounds in the PM samples. In all the samples, Me-PAHs were less abundant than unsubstituted PAHs. The PAH-CALUX assays were applied to evaluate aryl hydrocarbon receptor (AhR) ligand activities in crude extracts and different fractions from the PM samples. Benzo[a]pyrene equivalents (BaP-EQs) derived by the PAH-CALUX assays for low polar fractions (mainly PAHs and Me-PAHs) ranged from 300 to 840 ng/m, which were more consistent with theoretical values derived by using PAH-CALUX relative potencies (270-710 ng/m) rather than conventional toxic equivalency factor-based values (22-69 ng/m). Concentrations of PAHs and Me-PAHs highly correlated with bioassay-derived BaP-EQs. AhR-mediated activities of more polar compounds and interaction effects between PAH-related compounds were observed. By using PAH-CALUX BaP-EQs, the ILCR values ranged from 1.0 × 10 to 2.8 × 10 for adults and from 6.4 × 10 to 1.8 × 10 for children. Underestimation of cancer risk can be eliminated by using effect-directed method (e.g., PAH-CALUX) rather than chemical-specific approach.
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http://dx.doi.org/10.1016/j.chemosphere.2021.130720DOI Listing
April 2021

A new diphenyl ether from Hale growing in Vietnam.

Nat Prod Res 2021 Apr 7:1-7. Epub 2021 Apr 7.

Department of Chemistry, University of Education, Ho Chi Minh City, Vietnam.

Chemical investigation of the lichen Hale led to the isolation of one new diphenyl ether, parmetherine D (), along with eight known compounds (). The structures were determined by analysis of MS and NMR data and by comparison with the literature. Compounds , , and were evaluated for -glucosidase inhibition. Only compound exhibited significant inhibition.
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http://dx.doi.org/10.1080/14786419.2021.1907748DOI Listing
April 2021

Advances in biochemistry and the biotechnological production of taxifolin and its derivatives.

Biotechnol Appl Biochem 2021 Apr 2. Epub 2021 Apr 2.

Department of Medicinal Chemistry, University of Florida, Gainesville, Florida, USA.

Taxifolin (dihydroquercetin) and its derivatives are medicinally important flavanonols with a wide distribution in plants. These compounds have been isolated from various plants, such as milk thistle, onions, french maritime, and tamarind. In general, they are commercially generated in semisynthetic forms. Taxifolin and related compounds are biosynthesized via the phenylpropanoid pathway, and most of the biosynthetic steps have been functionally characterized. The knowledge gained through the detailed investigation of their biosynthesis has provided the foundation for the reconstruction of biosynthetic pathways. Plant- and microbial-based platforms are utilized for the expression of such pathways for generating taxifolin-related compounds, either by whole-cell biotransformation or through reconfiguration of the genetic circuits. In this review, we summarize recent advances in the biotechnological production of taxifolin and its derivatives.
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http://dx.doi.org/10.1002/bab.2156DOI Listing
April 2021

In vitro antimycobacterial studies of flavonols from Wight and Arn.

3 Biotech 2021 Mar 16;11(3):128. Epub 2021 Feb 16.

Institute of Research and Development, Duy Tan University, Da Nang, 550000 Vietnam.

Mycobacterial infections and fast-growing strains are increasing globally with 8 million new cases and 1.8 million fatalities per annum worldwide. The acid-fast bacterium, (), can spread diseases like tuberculosis (Tb) and weaken the immune system. In Ayurveda, the genus is most valued for the treatment of tuberculosis lymphadenitis. The objective of the present study is to identify anti-tubercular compounds from the under-investigated medicinal plant Wight and Arn. using bioassay guided isolation. The antimycobacterial activity was evaluated against non-virulent strains: H37Ra (ATCC 25177) and BCG (ATCC 35743). Also, antibacterial and cytotoxicity activities were tested to identify the specificity of the isolated metabolites. Bioassay-guided isolation yielded three known flavonols, namely quercetin , ombuin , and kaempferol from the methanolic extract of bark of . The results of antimycobacterial activity tests revealed that showed much better mycobactericidal activity than 1 and 3 under ex vivo condition with minimum inhibitory concentration (MIC) values ranged from 0.05 ± 0.01 to 0.26 ± 0.01 nM, and half-maximal inhibitory concentration (IC) values ranged from 2.85 ± 0.14 to 7.21 ± 1.09 nM against dormant and active forms, respectively. Also, compound showed higher resistance with MIC values > 100 μg/mL against both Gram-positive and Gram-negative bacteria and the least cytotoxicity up to 100 μg/mL concentration against the tested series of cancer cell lines. The results revealed the Ayurvedic use of extracts of the genus for treating tuberculosis, and the key bioactive compounds were found to be flavonols . The present work provides the first evidence for the presence of antimycobacterial compounds in .

Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-021-02672-4.
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http://dx.doi.org/10.1007/s13205-021-02672-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7885310PMC
March 2021

Parmosidone K, a new -depsidone from the lichen .

Nat Prod Res 2020 Nov 20:1-6. Epub 2020 Nov 20.

Department of Chemistry, Ho Chi Minh City University of Education, Ho Chi Minh City, Vietnam.

Further phytochemical investigation on led to one new -depsidone, parmosidone K together with one known compound, barbatic acid. Their structures were determined by 1D and 2D NMR analysis, high resolution mass spectroscopy, and comparison their NMR data with those reported in literatures. Parmosidone K was evaluated for α-glucosidase inhibition and revealed the powerful activity with IC value of 3.12 µM.
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http://dx.doi.org/10.1080/14786419.2020.1844697DOI Listing
November 2020

Validation of a Highly Sensitive qPCR Assay for the Detection of Plasma Cell-Free Epstein-Barr Virus DNA in Nasopharyngeal Carcinoma Diagnosis.

Cancer Control 2020 Jul-Aug;27(3):1073274820944286

Department of Genomics and Cytogenetics, Institute of Biomedicine & Pharmacy, Vietnam Military Medical University, Hanoi, Vietnam.

Quantification of plasma cell-free Epstein Barr virus DNA (cf EBV DNA) has been suggested as a promising liquid biopsy assay for screening and early detection of nasopharyngeal carcinoma (NPC). However, the diagnostic value of this assay is currently not known in the population of Vietnam, one of the countries which contributed the most to the NPC cases. Herein, we have reported a highly sensitive quantitative polymerase chain reaction (qPCR)-based assay targeting cf EBV DNA for the detection of NPC. A standard curve with linear regression, = 0.9961 (range: 25-150 000 copies/mL) and a detection limit of 25 copies/mL were obtained using an EBV standard panel provided by the Chinese University of Hong Kong. The clinical performance of this assay was assessed using plasma samples obtained from 261 Vietnamese individuals. The optimized qPCR assay detected cf EBV DNA in plasma with a sensitivity of 97.4% and a specificity of 98.2%. The absolute quantitative results of pretreatment cf EBV DNA and patient overall clinical stages were statistically correlated ( < .05). In summary, the remarkably high sensitivity and specificity of our optimized qPCR assay strongly supports the wide use of cf EBV DNA quantification as a routine noninvasive method in early diagnosis and management of patients with NPC.
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http://dx.doi.org/10.1177/1073274820944286DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7658724PMC
March 2021

Chronic Royal Jelly Administration Induced Antidepressant-Like Effects Through Increased Sirtuin1 and Oxidative Phosphorylation Protein Expression in the Amygdala of Mice.

Curr Mol Pharmacol 2021 ;14(2):115-122

Department of Pharmacology, Graduate School of Medical and Dental Science, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima890-8544, Japan.

Background: Major depressive disorder (MDD) is a common psychological disorder worldwide. However, one-third of patients with MDD are resistant to the present anti-depressant medicine, which regulates monoamine contents in the brain. Thus, another drug target is strongly required. Much evidence strongly suggests that sirtuin1, which is the key factor in regulating the mitochondrial activity, may be implicated in MDD.

Objective: Since it is suggested that royal jelly (RJ) ameliorated depressive-like behavior and affected mitochondrial activity in mice, we hypothesized that RJ could be an alternative medicine against MDD, which acts via sirtuin1 signaling to improve mitochondrial activity.

Methods: In the present study, we applied a mouse model of MDD to investigate the effect of RJ on the depressive-like behavior and the sirtuin1 signaling on mitochondrial activity.

Results: Our results indicated that either the oral administration of RJ for 12 days or single intracerebroventricular (i.c.v.) injection decreased the duration of immobility in the tail suspension test, which suggested that RJ had an antidepressant-like effect. Moreover, sirtuin1 protein expression increased in mice following RJ treatment in the amygdala region, but not in the other brain regions. Similarly, the expressions of oxidative phosphorylation (OXPHOS) related proteins increased in the amygdala regions, but not in the hippocampal regions.

Conclusion: The increase of sirtuin1 and OXPHOS protein expression may at least in part contribute to the antidepressant-like effect of the RJ pathway, and RJ may have the potential to be a novel anti-depressant drug.
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http://dx.doi.org/10.2174/1874467213666200424160153DOI Listing
January 2021

Subnudatones A and B, new trans-decalin polyketides from the cultured lichen mycobionts of Pseudopyrenula subnudata.

Fitoterapia 2020 Apr 13;142:104512. Epub 2020 Feb 13.

Pham Van Dong University, Quang Ngai Province, Viet Nam. Electronic address:

Chemical investigation of the cultured polyspore-derived mycobionts of a Pseudopyrenula subnudata lichen led to the isolation of two new compounds, subnudatones A and B (1 and 2), together with four known compounds, 1-(2-hydroxy-1,2,6-trimethyl-1,2,4a,5,6,7,8,8a-octahydronaphthalen-1-yl)ethanone (3), libertalide C (4), aspermytin A (5), and 6,7-dimethoxy-4-hydroxymellin (6). Their chemical structures were elucidated by extensive 1D and 2D NMR analysis and high resolution mass spectroscopy, and comparisons were made with the literature. The absolute configuration of 1 was defined unambiguously using single crystal X-ray crystallography. Compound 1 represents the first dimeric decalin polyketide to be found in nature. The in vitro cytotoxicity of 1 against two cancer cell lines (K562 and MCF-7) was evaluated. Compound 1 showed moderate cytotoxic activity with IC values of 23.5 ± 1.0 and 51.9 ± 1.4 μM, respectively.
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http://dx.doi.org/10.1016/j.fitote.2020.104512DOI Listing
April 2020

Dilatatone, a new chlorinated compound from .

Nat Prod Res 2020 Jan 27:1-5. Epub 2020 Jan 27.

Faculty of Chemistry, University of Education, Ho Chi Minh City, Vietnam.

Chemical investigation of the lichen led to the isolation of a new chlorinated compound, named dilatatone (), along with a known compound, sernanderin (). Their chemical structures were determined by analysis of their 1 D and 2 D NMR spectra, HRESIMS, and ECD data. Both compounds showed weak glucosidase inhibitor activity.
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http://dx.doi.org/10.1080/14786419.2020.1716348DOI Listing
January 2020

Pituitary Adenylate Cyclase-Activating Polypeptide in the Ventromedial Hypothalamus Is Responsible for Food Intake Behavior by Modulating the Expression of Agouti-Related Peptide in Mice.

Mol Neurobiol 2020 Apr 11;57(4):2101-2114. Epub 2020 Jan 11.

Department of Pharmacology, Graduate School of Medical and Dental Science, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima, 890-8544, Japan.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is abundantly expressed in the hypothalamus and contributes to hypothalamic functions, including appetite regulation. Although food intake is suggested to be decreased in PACAP (-/-) mice, the detailed mechanisms are still being discussed. We sought to investigate this link. The food consumption at 8 h after refeeding in the (-/-) mice who had fasted for 2 days was significantly lower than in the PACAP (+/+) mice. The nocturnal and daily food intake of (-/-) mice was significantly lower than those of (+/+) mice, but the diurnal food intake showed a tendency to increase. mRNA expression levels of agouti-related peptide (AgRP) were decreased, but those of proopiomelanocortin (POMC) were increased in the hypothalamus of (-/-) mice 4 h after refeeding. Furthermore, intracerebroventricular administration of a PACAP receptor antagonist, PACAP (1 nmol/4 μL/mouse), decreased food intake and body weight 1, 2, and 4 h after refeeding, as well as expression levels of AgRP at 4 h after refeeding in (+/+) mice. The selective overexpression of PACAP by the infection of an adeno-associated virus in the ventromedial hypothalamus (VMH) resulted in an increase in food intake and AgRP expression in the nocturnal period in addition to the increased food intake at 8 h after refeeding. These results suggest that food intake behavior in mice is triggered by the increase in PACAP expression in the VMH via modulation of AgRP expression in the hypothalamus, pointing to PACAP inhibition as a potential strategy for the development of anti-obesity drugs.
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http://dx.doi.org/10.1007/s12035-019-01864-7DOI Listing
April 2020

Soil and sediment contamination by unsubstituted and methylated polycyclic aromatic hydrocarbons in an informal e-waste recycling area, northern Vietnam: Occurrence, source apportionment, and risk assessment.

Sci Total Environ 2020 Mar 5;709:135852. Epub 2019 Dec 5.

Centre for Environmental Technology and Sustainable Development (CETASD), VNU University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Hanoi, Viet Nam. Electronic address:

Improper processing activities of e-waste are potential sources of polycylic aromatic hydrocarbons (PAHs) and their derivatives, however, information about the environmental occurrence and adverse impacts of these toxic substances is still limited for informal e-waste recycling areas in Vietnam and Southeast Asia. In this study, unsubstituted and methylated PAHs were determined in surface soil and river sediment samples collected from a rural village with informal e-waste recycling activities in northern Vietnam. Total levels of PAHs and MePAHs decreased in the order: workshop soil (median 2900; range 870-42,000 ng g) > open burning soil (2400; 840-4200 ng g) > paddy field soil (1200; range 530-6700 ng g) > river sediment samples (750; 370-2500 ng g). About 60% of the soil samples examined in this study were heavily contaminated with PAHs. Fingerprint profiles of PAHs and MePAHs in the soil and sediment samples indicated that these pollutants were mainly released from pyrogenic sources rather than petrogenic sources. The emissions of PAHs and MePAHs in this area were probably attributed to uncontrolled burning of e-waste and agricultural by-products, domestic coal and biomass combustion, and traffic activities. Carcinogenicity and mutagenicity of PAHs in the e-waste workshop soils were significantly higher than those of the field soils; however, the incremental lifetime cancer risk of PAH-contaminated soils in this study ranged from 5.5 × 10 to 4.6 × 10, implying acceptable levels of human health risk. Meanwhile, concentrations of some compounds such as phenanthrene, anthracene, fluoranthene, benz[a]anthracene, and benzo[a]pyrene in several soil samples exceeded the maximum permissible concentrations, indicating the risk of ecotoxicological effects.
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http://dx.doi.org/10.1016/j.scitotenv.2019.135852DOI Listing
March 2020

Allelochemicals and Signaling Chemicals in Plants.

Molecules 2019 Jul 27;24(15). Epub 2019 Jul 27.

Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam.

Plants abound with active ingredients. Among these natural constituents, allelochemicals and signaling chemicals that are released into the environments play important roles in regulating the interactions between plants and other organisms. Allelochemicals participate in the defense of plants against microbial attack, herbivore predation, and/or competition with other plants, most notably in allelopathy, which affects the establishment of competing plants. Allelochemicals could be leads for new pesticide discovery efforts. Signaling chemicals are involved in plant neighbor detection or pest identification, and they induce the production and release of plant defensive metabolites. Through the signaling chemicals, plants can either detect or identify competitors, herbivores, or pathogens, and respond by increasing defensive metabolites levels, providing an advantage for their own growth. The plant-organism interactions that are mediated by allelochemicals and signaling chemicals take place both aboveground and belowground. In the case of aboveground interactions, mediated air-borne chemicals are well established. Belowground interactions, particularly in the context of soil-borne chemicals driving signaling interactions, are largely unknown, due to the complexity of plant-soil interactions. The lack of effective and reliable methods of identification and clarification their mode of actions is one of the greatest challenges with soil-borne allelochemicals and signaling chemicals. Recent developments in methodological strategies aim at the quality, quantity, and spatiotemporal dynamics of soil-borne chemicals. This review outlines recent research regarding plant-derived allelochemicals and signaling chemicals, as well as their roles in agricultural pest management. The effort represents a mechanistically exhaustive view of plant-organism interactions that are mediated by allelochemicals and signaling chemicals and provides more realistic insights into potential implications and applications in sustainable agriculture.
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http://dx.doi.org/10.3390/molecules24152737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6695906PMC
July 2019

Rapid Disappearance of Poliovirus Type 2 (PV2) Immunity in Young Children Following Withdrawal of Oral PV2-Containing Vaccine in Vietnam.

J Infect Dis 2019 07;220(3):386-391

National Institute of Hygiene and Epidemiology, Hanoi, Vietnam.

Background: Due to global shortage of inactivated poliovirus vaccine and withdrawal of oral vaccine containing poliovirus type 2 (PV2), a PV2-containing vaccine was not used in Vietnam May 2016 to October 2018. We assessed the population immunity gap to PV2.

Methods: A cross-sectional survey in children aged 1-18 months was carried out in January 2018. One blood sample per child was analyzed for presence of poliovirus neutralizing antibodies. In children with detectable anti-PV2 antibodies, a second sample was analyzed 4 months later to distinguish between passive (maternally derived) and active (induced by secondary transmission or vaccination) immunity.

Results: Sera were obtained from 1106/1110 children. Seroprevalence of PV2 antibodies was 87/368 (23.6%) at age 1-7 months, 27/471 (5.7%) at 8-15 months, and 19/267 (7.1%) at 16-18 months. Seroprevalence declined with age in the 1-7 months group; in the 8-18 months group there was no significant change with age. Four months later, 11/87 (14%), 9/27 (32%), and 12/19 (37%) remained seropositive in 1-7, 8-15, and 16-18 months age groups, respectively.

Conclusions: We found declining immunity to PV2, suggesting Vietnam is at risk for an outbreak of type 2 vaccine-derived poliovirus following virus importation or new emergence.
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http://dx.doi.org/10.1093/infdis/jiz124DOI Listing
July 2019

An optimized molecular method for detection of influenza A virus using improved generic primers and concentration of the viral genomic RNA and nucleoprotein complex.

J Vet Diagn Invest 2019 Mar 22;31(2):175-183. Epub 2019 Feb 22.

Laboratory of Avian Diseases (J-W Kim, Lee, Nguyen, J-H Kim), College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.

For reported primer sets used to detect influenza A viruses (IAVs), we verified the nucleotide identities with 9,103 complete sequences of matrix (M) genes. At best, only 93.2% and 85.3% of the sequences had a 100% match with reported forward and reverse primers, respectively. Therefore, we designed new degenerate forward and reverse primers with 100% identity to 94.4% and 96.2% of compared genes, respectively, and the primer set was used with SYBR-based reverse-transcription real-time PCR (SYBR-RT-rtPCR) for lower detection limits. The sensitivity of SYBR-RT-rtPCR with the new primers was 10-fold higher than that with a conventional method in ~2.37% of all M genes in the database used in our study. We successfully increased the sensitivity of SYBR-RT-rtPCR by concentrating the viral ribonucleoprotein (RNP) using immunomagnetic beads and Triton X-100. The improved generic primer set and RNP concentration method may be useful for sensitive detection of IAVs.
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http://dx.doi.org/10.1177/1040638719830760DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6838833PMC
March 2019

An auto-inducible phosphate-controlled expression system of Bacillus licheniformis.

BMC Biotechnol 2019 01 9;19(1). Epub 2019 Jan 9.

Pharmaceutical Biotechnology, Institute of Pharmacy, University Greifswald, Greifswald, Germany.

Background: A promoter that drives high-level, long-term expression of the target gene under substrate limited growth conditions in the absence of an artificial inducer would facilitate the efficient production of heterologous proteins at low cost. A novel phosphate-regulated expression system was constructed using the promoter of the phytase encoding gene phyL from Bacillus licheniformis for the overexpression of proteins in this industrially relevant host.

Results: It is shown that the phyL promoter enables a strong overexpression of the heterologous genes amyE and xynA in B. licheniformis when cells were subjected to phosphate limitation. Whether B. licheniformis can use phytate as an alternative phosphate source and how this substrate influences the PphyL controlled gene expression under growth conditions with limited inorganic phosphate concentrations were also investigated. It is shown that B. licheniformis cells are able to use sodium phytate as alternative phosphate source. The addition of small amounts of sodium phytate (≤ 5 mM) to the growth medium resulted in a strong induction and overexpression of both model genes in B. licheniformis cells under phosphate limited growth conditions.

Conclusions: The PphyL controlled expression of the investigated heterologous genes in B. licheniformis is strongly auto-induced under phosphate limited conditions. The proposed PphyL expression system enables an overexpression of target genes in B. licheniformis under growth conditions, which can be easily performed in a fed-batch fermentation process.
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http://dx.doi.org/10.1186/s12896-018-0490-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6327384PMC
January 2019

Escherichia coli modular coculture system for resveratrol glucosides production.

World J Microbiol Biotechnol 2018 May 23;34(6):75. Epub 2018 May 23.

Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800, Kongens Lyngby, Denmark.

In bio-based fermentation, the overall bioprocess efficiency is significantly affected by the metabolic burden associated with the expression of complete biosynthetic pathway as well as precursor and cofactor generating enzymes into a single microbial cell. To attenuate such burden by compartmentalizing the enzyme expression, recently synthetic biologists have used coculture or poly-culture techniques for biomolecules synthesis. In this paper, coculture system of two metabolically engineered Escherichia coli populations were employed which comprises upstream module expressing two enzymes converting para-coumaric acid into resveratrol and the downstream module expressing glucosyltransferase to convert the resveratrol into its glucosidated forms; polydatin and resveratroloside. Upon optimization of the initial inoculum ratio of two E. coli populations, 92 mg resveratrol glucosides/L (236 µM) was produced i.e. achieving 84% bioconversion from 280 µM of p-coumaric acid in 60 h by 3 L fed batch fermentor. This is the report of applying coculture system to produce resveratrol glucosides by expressing the aglycone formation pathway and sugar dependent pathway into two different cells.
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http://dx.doi.org/10.1007/s11274-018-2458-zDOI Listing
May 2018

Epidemiology of acute diarrhea caused by rotavirus in sentinel surveillance sites of Vietnam, 2012-2015.

Vaccine 2018 12 18;36(51):7894-7900. Epub 2018 May 18.

National Institute of Hygiene and Epidemiology, Hanoi, Vietnam. Electronic address:

A prospective, multicentre study was conducted in four sentinel surveillance hospitals to assess the trend and epidemiology of acute diarrhea caused by Rotavirus in Vietnam. During the period 2012-2015, a total 8,889 children under 5 years of age were enrolled in the surveillance, and 8689 stool samples were collected. Of these cases, Rotavirus was most common pathogen 46.7% (4054 cases); in which 26.6% (1117) rotavirus-positive stool samples were evaluated to identify genotypes. The proportion of rotavirus positive specimens decreased annually from 54.7% in 2012 to 36.6% in 2015. Rotavirus was detected year-round, but most rotavirus gastroenteritis cases (77.1%) occurred between December and May, corresponding to the rotavirus seasonality. It is found that the peaks varied by regions. Rotavirus positivities varied between the youngest and oldest age, but children 6-11 months old (38.8%) and 12-23 months old (38.4%) counted for most cases. A significant higher number of diarrhea within 24 hours (8.3 times, 95%CI: 8.1-8.4 times) and higher proportion of severe dehydration (12.9%) in Rotavirus positive group than that in Rotavirus negative group (7.7 times, 95%CI: 7.6-7.9 times; and 9.7%, respectively). A downtrend of prevalence of G1P[8] was observed from 82% in 2013 to 15% in 2015. However, G2P[4] was found in 5% of samples in 2012, 9% in 2013, 36% in 2014, and 28% in 2015. Rotavirus infection is the most important cause of acute diarrhea among hospitalized children in Vietnam, and a rotavirus vaccination program for children may significantly reduce this disease.
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http://dx.doi.org/10.1016/j.vaccine.2018.05.008DOI Listing
December 2018

Evaluating Food Safety Knowledge and Practices of Food Processors and Sellers Working in Food Facilities in Hanoi, Vietnam.

J Food Prot 2018 04;81(4):646-652

2 Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA.

Consumption of fast food and street food is increasingly common among Vietnamese, particularly in large cities. The high daily demand for these convenient food services, together with a poor management system, has raised concerns about food hygiene and safety (FHS). This study aimed to examine the FHS knowledge and practices of food processors and sellers in food facilities in Hanoi, Vietnam, and to identify their associated factors. A cross-sectional study was conducted with 1,760 food processors and sellers in restaurants, fast food stores, food stalls, and street vendors in Hanoi in 2015. We assessed each participant's FHS knowledge using a self-report questionnaire and their FHS practices using a checklist. Tobit regression was used to determine potential factors associated with FHS knowledge and practices, including demographics, training experience, and frequency of health examination. Overall, we observed a lack of FHS knowledge among respondents across three domains, including standard requirements for food facilities (18%), food processing procedures (29%), and food poisoning prevention (11%). Only 25.9 and 38.1% of participants used caps and masks, respectively, and 12.8% of food processors reported direct hand contact with food. After adjusting for socioeconomic characteristics, these factors significantly predicted increased FHS knowledge and practice scores: (i) working at restaurants and food stalls, (ii) having FHS training, (iii) having had a physical examination, and (iv) having taken a stool test within the last year. These findings highlight the need of continuous training to improve FHS knowledge and practices among food processors and food sellers. Moreover, regular monitoring of food facilities, combined with medical examination of their staff, should be performed to ensure food safety.
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http://dx.doi.org/10.4315/0362-028X.JFP-17-161DOI Listing
April 2018

Effect of the fourth nucleotide at the 3' end of neuraminidase and matrix viral genomic RNA on the pathogenicity of influenza virus A/PR/8/34.

J Vet Sci 2017 Aug;18(S1):307-313

Laboratory of Avian Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea.

Twelve nucleotides located at the 3' end of viral genomic RNA (vRNA) are conserved among influenza A viruses (IAV) and have a promoter function. Hoffmann's 8-plasmid reverse genetics vector system introduced mutations at position 4, C nucleotide (C4) to U nucleotide (U4), of the 3' ends of neuraminidase (NA) and matrix (M) vRNAs of wild-type A/PR/8/34 (PR8). This resulted in a constellation of C4 and U4 vRNAs coding for low (polymerases) and relatively high (all others) copy number proteins, respectively. U4 has been reported to increase promoter activity in comparison to C4, but the constellation effect on the replication efficiency and pathogenicity of reverse genetics PR8 (rgPR8) has not been fully elucidated. In the present study, we generated 3 recombinant viruses with C4 in the NA and/or M vRNAs and rgPR8 by using reverse genetics and compared their pathobiological traits. The mutant viruses showed lower replication efficiency than rgPR8 due to the low transcription levels of NA and/or M genes. Furthermore, C4 in the NA and/or M vRNAs induced lower PR8 virus pathogenicity in BALB/c mice. The results suggest that the constellation of C4 and U4 among vRNAs may be one of the multigenic determinants of IAV pathogenicity.
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http://dx.doi.org/10.4142/jvs.2017.18.S1.307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5583418PMC
August 2017

Prevalence and genotype distribution of hepatitis delta virus among chronic hepatitis B carriers in Central Vietnam.

PLoS One 2017 12;12(4):e0175304. Epub 2017 Apr 12.

Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany.

Hepatitis D virus (HDV) infection plays an important role in liver diseases. However, the molecular epidemiology and impact of HDV infection in chronic hepatitis B (CHB) remain uncertain in Vietnam. This cross-sectional study aimed to investigate the prevalence and genotype distribution of HDV among HBsAg-positive patients in Central Vietnam. 250 CHB patients were tested for HDV using newly established HDV-specific RT-PCR techniques. HDV genotypes were determined by direct sequencing. Of the 250 patients 25 (10%) had detectable copies of HDV viral RNA. HDV-2 was predominant (20/25; 80%) followed by HDV-1 (5/25; 20%). Proven HDV genotypes share the Asian nomenclature. Chronic hepatitis B patients with concomitant HDV-1 showed higher HBV loads as compared to HDV-2 infected patients [median log10 (HBV-DNA copies/ml): 8.5 vs. 4.4, P = 0.036]. Our findings indicate that HDV infection is highly prevalent and HDV-2 is predominant in Central Vietnam. The data will add new information to the management of HBsAg-positive patients in a highly HBV endemic region to in- or exclude HDV infection in terms of diagnostic and treatment options.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0175304PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5389633PMC
April 2017

Microbial production of astilbin, a bioactive rhamnosylated flavanonol, from taxifolin.

World J Microbiol Biotechnol 2017 Feb 24;33(2):36. Epub 2017 Jan 24.

Department of Life Science and Biochemical Engineering, SunMoon University, 70 Sunmoon-ro 221, Tangjeong-myeon, Asan-si, Chungnam, 31460, Republic of Korea.

Flavonoids are plant-based polyphenolic biomolecules with a wide range of biological activities. Glycosylated flavonoids have drawn special attention in the industries as it improves solubility, stability, and bioactivity. Herein, we report the production of astilbin (ATN) from taxifolin (TFN) in genetically-engineered Escherichia coli BL21(DE3). The exogenously supplied TFN was converted to ATN by 3-O-rhamnosylation utilizing the endogeneous TDP-L-rhamnose in presence of UDP-glycosyltransferase (ArGT3, Gene Bank accession number: At1g30530) from Arabidopsis thaliana. Upon improving the intracellular TDP-L-rhamnose pool by knocking out the chromosomal glucose phosphate isomerase (pgi) and D-glucose-6-phosphate dehydrogenase (zwf) deletion along with the overexpression of rhamnose biosynthetic pathway increases the biotransformation product, ATN with total conversion of ~49.5 ± 1.67% from 100 µM of taxifolin. In addition, the cytotoxic effect of taxifolin-3-O-rhamnoside on PANC-1 and A-549 cancer cell lines was assessed for establishing ATN as potent antitumor compound.
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http://dx.doi.org/10.1007/s11274-017-2208-7DOI Listing
February 2017

Cost-Effectiveness Analysis of Screening for and Managing Identified Hypertension for Cardiovascular Disease Prevention in Vietnam.

PLoS One 2016 18;11(5):e0155699. Epub 2016 May 18.

University of Groningen, Department of Pharmacy, Unit of PharmacoEpidemiology & PharmacoEconomics, Groningen, the Netherlands.

Objective: To inform development of guidelines for hypertension management in Vietnam, we evaluated the cost-effectiveness of different strategies on screening for hypertension in preventing cardiovascular disease (CVD).

Methods: A decision tree was combined with a Markov model to measure incremental cost-effectiveness of different approaches to hypertension screening. Values used as input parameters for the model were taken from different sources. Various screening intervals (one-off, annually, biannually) and starting ages to screen (35, 45 or 55 years) and coverage of treatment were analysed. We ran both a ten-year and a lifetime horizon. Input parameters for the models were extracted from local and regional data. Probabilistic sensitivity analysis was used to evaluate parameter uncertainty. A threshold of three times GDP per capita was applied.

Results: Cost per quality adjusted life year (QALY) gained varied in different screening scenarios. In a ten-year horizon, the cost-effectiveness of screening for hypertension ranged from cost saving to Int$ 758,695 per QALY gained. For screening of men starting at 55 years, all screening scenarios gave a high probability of being cost-effective. For screening of females starting at 55 years, the probability of favourable cost-effectiveness was 90% with one-off screening. In a lifetime horizon, cost per QALY gained was lower than the threshold of Int$ 15,883 in all screening scenarios among males. Similar results were found in females when starting screening at 55 years. Starting screening in females at 45 years had a high probability of being cost-effective if screening biannually was combined with increasing coverage of treatment by 20% or even if sole biannual screening was considered.

Conclusion: From a health economic perspective, integrating screening for hypertension into routine medical examination and related coverage by health insurance could be recommended. Screening for hypertension has a high probability of being cost-effective in preventing CVD. An adequate screening strategy can best be selected based on age, sex and screening interval.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0155699PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4871542PMC
July 2017

A Phosphate Starvation-Inducible Ribonuclease of Bacillus licheniformis.

J Microbiol Biotechnol 2016 Aug;26(8):1464-72

Pharmaceutical Biotechnology, Institute of Pharmacy, Ernst-Moritz-Arndt-University, 17489 Greifswald, Germany.

The BLi03719 protein of Bacillus licheniformis DSM13 belongs to the most abundant extracellular proteins under phosphate starvation conditions. In this study, the function of this phosphate starvation inducible protein was determined. An amino-acid sequence analysis of the BLi03719-encoding gene showed a high similarity with genes encoding the barnase of Bacillus amyloliquefaciens FZB42 and binase-like RNase of Bacillus pumilus SARF-032. The comparison of the control strain and a BLi03719-deficient strain revealed a strongly reduced extracellular ribonuclease activity of the mutant. Furthermore, this knockout mutant exhibited delayed growth with yeast RNA as an alternative phosphate and carbon source. These results suggest that BLi03719 is an extracellular ribonuclease expressed in B. licheniformis under phosphate starvation conditions. Finally, a BLi03719 mutant showed an advantageous effect on the overexpression of the heterologous amyE gene under phosphate-limited growth conditions.
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http://dx.doi.org/10.4014/jmb.1601.01087DOI Listing
August 2016

Integrated electronic system for implantable sensory NFC tag.

Annu Int Conf IEEE Eng Med Biol Soc 2015 ;2015:7119-22

We have designed the complete electronic system for an implanted sensory NFC-A tag (type 1) that monitors a physiological parameter, e.g. blood glucose, dehydration, bladder pressure, to name some of the target applications that we pursue. The tag is meant to be implanted under the skin and is powered by an NFC reader held close to it, such as a smart phone or a smart watch. The electronic system consists of a sensor front-end, ADC, NFC-A transceiver and NFC power harvester. In its present status, the physical layer of the communication and the power harvester have been implemented on one ASIC, and the sensor front-end and ADC on another, while the digital circuits realizing the higher level NFC protocol have been implemented on an FPGA. Simulations and a few preliminary test results are presented in this paper. The ultimate goal after thorough testing of this first prototype is to integrate all of these modules on a single ASIC.
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http://dx.doi.org/10.1109/EMBC.2015.7320033DOI Listing
September 2016

Bifidobacterium species lower serum glucose, increase expressions of insulin signaling proteins, and improve adipokine profile in diabetic mice.

Biomed Res 2015 ;36(1):63-70

Department of Food Microbiology, National Institute for Food Control.

This study, using C57BL/6J mice with streptozotocin (STZ)-induced diabetes, aimed to determine whether Bifidobacterium species (spp.) both induces the expressions of proteins in the insulin signaling pathway and enhances the expressions of certain adipocytokines. The protein expressions of IκB kinase alpha (IKKα), IκB kinase beta (IKKβ), nuclear factor-kappaB inhibitor alpha (IκBα), and the mitogen-activated protein kinase (MAPK) pathway were also investigated. Oral administration of Bifidobacterium spp. reduced blood glucose levels significantly and increased the protein expressions of insulin receptor beta, insulin receptor substrate 1, protein kinase B (Akt/PKB), IKKα, and IκBα. Extracellular-signal-regulated kinase 2 (ERK2) showed increased expression. Bifidobacterium spp. also induced the adiponectin expression and decreased both macrophage chemoattractant protein-1 (MCP-1) and interleukin-6 (IL-6) expression. In addition, IKKβ, c-Jun NH2-terminal kinase (JNK) and p38 MAP kinase expressions showed no significant changes in both groups. In conclusion, Bifidobacterium spp. may be the promising bacteria for treating diabetes.
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http://dx.doi.org/10.2220/biomedres.36.63DOI Listing
November 2015

Direct costs of hypertensive patients admitted to hospital in Vietnam- a bottom-up micro-costing analysis.

BMC Health Serv Res 2014 Oct 28;14:514. Epub 2014 Oct 28.

Background: There is an economic burden associated with hypertension both worldwide and in Vietnam. In Vietnam, patients with uncontrolled high blood pressure are hospitalized for further diagnosis and initiation of treatment. Because there is no evidence on costs of inpatient care for hypertensive patients available yet to inform policy makers, health insurance and hospitals, this study aims to quantify direct costs of inpatient care for these patients in Vietnam.

Methods: A retrospective study was conducted in a hospital in Vietnam. Direct costs were analyzed from the health-care provider's perspective. Hospital-based costing was performed using both bottom-up and micro-costing methods. Patients with sole essential or primary hypertension (ICD-code I10) and those comorbid with sphingolipid metabolism or other lipid storage disorders (ICD-code E75) were selected. Costs were quantified based on financial and other records of the hospital. Total cost per patient resulted from an aggregation of laboratory test costs, drug costs, inpatient-days' costs and other remaining costs, including appropriate allocation of overheads. Both mean and medians, as well as interquartile ranges (IQRs) were calculated. In addition to a base-case analysis, specific scenarios were analyzed.

Results: 230 patients were included in the study (147 cases with I10 code only and 83 cases with I10 combined with E75). Median length of hospital stay was 6 days. Median total direct costs per patient were US$65 (IQR: 37 -95). Total costs per patient were higher in the combined hypertensive and lipid population than in the sole hypertensive population at US$78 and US$53, respectively. In all scenarios, hospital inpatient days' costs were identified as the major cost driver in the total costs.

Conclusions: Costs of hospitalization of hypertensive patients is relatively high compared to annual medication treatment at a community health station for hypertension as well as to the total health expenditure per capita in Vietnam. Given that untreated/undetected hypertension likely leads to more expensive treatments of complications, these findings may justify investments by the Vietnamese health-care sector to control high blood pressure in order to save downstream health care budgets.
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http://dx.doi.org/10.1186/s12913-014-0514-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4221683PMC
October 2014

Influence of varying levels of supplemental cassava root meal without or with groundnut cake on performance of growing Laisind cattle.

Trop Anim Health Prod 2014 Aug 9;46(6):925-30. Epub 2014 Apr 9.

Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, P.O. Box 5003 IHA-NMBU, 1430, Ǻs, Norway,

The objective of this study was to evaluate the effect of supplementation of varying levels of cassava root meal (CRM, 300 and 1,000 g), without or with 700 g groundnut cake (GNC) on intake and performance of growing Laisind cattle fed with a basal diet of urea-treated rice straw (URTRS). Twenty-four male cattle of crossbred Laisind (50% Red Sindhi and 50 % local Yellow, both Bos indicus), from 15 to 17 months of age, 165-175 kg body weight, were used. They were assigned to a completely randomized block design in a 2 × 2 factorial arrangement (two CRM levels and two GNC levels). Intake of URTRS (interaction, P < 0.01) and digestibility of neutral detergent fiber (interaction, P < 0.05) decreased as CRM level increased on the diets without GNC but was not affected by CRM level on the diets with GNC. The total dry matter intake (interaction, P < 0.05) and live weight gain (LWG) (interaction, P < 0.001) increased as CRM level increased on the diets with GNC, but no difference was observed on the diets without GNC. In conclusion, supplementation of 1,000 g CRM should be in combination with 700 g GNC to avoid the negative effects on URTRS intake and digestibility, therefore improving LWG of growing Laisind cattle fed on a URTRS-based diet.
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http://dx.doi.org/10.1007/s11250-014-0586-5DOI Listing
August 2014

Multiplex nested RT-PCR for detecting avian influenza virus, infectious bronchitis virus and Newcastle disease virus.

J Virol Methods 2013 Mar 20;188(1-2):41-6. Epub 2012 Dec 20.

Laboratory of Avian Diseases, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea.

In this study, multiplex nested RT-PCR (mnRT-PCR) was applied to simultaneous detect multiplex PCR with the higher sensitivity of nested PCR that is required for avian influenza, infectious bronchitis and Newcastle disease virus using two steps of amplification. For the first PCR, primers that were specific for each virus were newly designed from the nucleoprotein gene of AIV, the nucleocapsid protein gene of IBV and the fusion protein gene of NDV to amplify products of 665, 386 and 236 nucleotides, respectively. The multiplex PCR step provides mass amplification using common primers, which increased markedly the sensitivity of the test. Non-specific reactions were not observed when other viruses and bacteria were used for evaluating the mnRT-PCR. As a field application, 172 samples were tested by RT-PCR and mnRT-PCR. Among these samples, the concordance rates for mnRT-PCR and the single conventional RT-PCR showed 98.9% (kappa=0.98) and 98.8% (kappa=0.96) similarity for IBV and AIV, respectively. As a result, it is recommended the multiplex nested PCR as an effective tool for detecting and studying the molecular epidemiology of various mixed infections of one or more of these viruses in poultry.
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http://dx.doi.org/10.1016/j.jviromet.2012.12.004DOI Listing
March 2013