Search

The prokaryotic community in sediment plays an important role in the nutrient cycles of lagoon ecosystems. However, the diversity of microbiota in sediments of Vietnamese lagoons has not been discovered. In this study, sediment samples from three lagoons in Central Vietnam were collected. The microbial community structure in the sediments was determined using Illumina sequencing of 16S rRNA at V3V4 regions. Mother software was used to analyze the data and identify the Operational Taxonomic Units (OTUs). Proteobacteria, Firmicutes, Campilobacterota, and Bacteroidetes were the major phyla in three lagoons, while Fusobacteria, Verrucomicrobia, Acidobacteria, Actinobacteria, and Chloroflexi were the minor. These groups of bacteria have been reported to be involved in organic metabolism cycles in sediments. Tam Giang lagoon showed more diversity in species composition when compared with Nai and Thi Nai lagoons. Class Clostridia were predominant in Tam Giang sediment (46%), which may indicate the presence of organic sewage in the environment. Thi Nai and Nai lagoons witnessed the significant presence of Lactobacilales and Vibrionales. While Vibrionales is an indicator of urban pollution, Lactobacilales and other groups of phylum Actinobacteria were potential materials for the screening of natural antibiotics.

Supervisor:NGUYEN, Le Minh, 先端科学技術研究科, 修士(情報科学）

The bacteria capable of fixing atmospheric nitrogen were isolated from cassava cultivated soils of Vietnam. The potential isolates were identified by analyzing the 16S rRNA gene and by morphological, biochemical, cultural characteristics. The selected isolates were assigned to the species Bacillus sp. DQT2 M17, Bacillus subtilis DTAN6 M17, and Bacillus megaterium DSHB I8. The effect of culture conditions on the nitrogen-fixing activity of three selected isolates were studied and the obtained results showed that the highest amount of accumulated ammonia was detected after 6 days of incubation at 35 oC, pH 7.0 with sucrose as a carbon source. The selected strains could be exploited as inoculants for microbial fertilizer production.

Currently, searching for new protease inhibitors is of interest to many scientists around the world because they play an important role in controlling harmful proteases. As terrestrial bioactive resources are becoming increasingly depleted, studies are aimed at finding other sources, for example, the ocean. Some recent reports indicate that sponge- associated microbes produce substances with high biological activity, such as anticancer and anti-inflammation, protease inhibition, etc. In this report, a new serpin gene screened from the metagenomics database of microorganism-associated Spheciospongia vesparium QT2 collected sea of Quang Tri province (Vietnam), was successful expressed in Pichia pastoris SMD1168. The obtained result showed that the maximum amount of recombinant protein secreted in the medium was received after 72 hours of induction with methanol. The PAGE electrophoresis supplemented with 0.1% casein and the Trypsin-sepharose 4B affinity chromatography column were performed, and the result was confirmed that the recombinant protein expressed in the P. pastoris SMD1168 (molecular weight about 50 kDa) was the target protein. The purified recombinant protein PI-QT exhibited inhibitor activity on trypsin, ɑ-chymotrypsin and thermolysin and the inhibition was 88.7%, 69% and 43%, respectively. In addition, PI-QT protein is stable and has optimal activity in the pH range 7−9, the temperature is below 60 oC.

Introduction: Proteases are enzymes that catalyze the hydrolysis of peptide bonds and play an important role in almost all biological processes. However, excessive protein proteolysis can be implicated in several diseases, such as cancer, as well as cardiovascular, inflammatory, neurodegenerative, bacterial, viral and parasitic diseases. In these cases, protease inhibitors can be used as one of versatile tools for regulating proteolytic activity of target proteases as well as therapeutic applications. In this study, we expressed and characterized a new serine protease inhibitory protein (PI-QT) from the metagenome of sponge-associated microorganisms in Escherichia coli. Methods: The gene PI-QT encoding for a new serine protease inhibitory protein was expressed in E. coli BL21(DE3). In addition, the expressed protein was purified and characterized. Results: Optimization of expression of the recombinant protein PI-QT in E. coli showed that suitable conditions for expression of the protein were pre-induction cell density (OD600) of 0.6 - 0.7, IPTG concentration of 1 mM and temperature of 25oC. The protease inhibitory protein was also purified and identified by mass spectrometry LC-MS/MS. The recombinant protein showed inhibitory activity against trypsin anda-chymotrypsin with activity values of 97526 U/mg and 41714 U/mg, respectively. Maximum activity of the protease inhibitory protein was obtained at pH 7 and temperature 20-35oC. The inhibitor was stable over pH 4-9 and up to temperature 50oC. Addition of Zn2+, Mg2+ and Ca2+ enhanced inhibitory activity, whereas other metal ions, surfactants and oxidants reduced inhibitory activity of the protease inhibitor. Conclusion: The recombinant protein PI-QT is a potential protease inhibitor for therapeutic applications.

The ECHO (Extension for Community Health Outcomes) model has been introduced and implemented in several hospitals and health programs in Vietnam since 2015. In 2018, Vietnam National Children’s Hospital (VNCH) officially implemented the ECHO model to provide continuing medical education (CME) credits on pediatrics topics for medical staff in its satellite hospitals and health centers in the Northern region of Vietnam. This paper presents preliminary results of the ECHO program at VNCH. Methods included pre- and post-program assessments of pediatricians’ clinical knowledge, self-efficacy, and professional satisfaction. The analysis compared the differences between pre/post scores descriptively. Knowledge of participants increased by 22.5% points on average. More than 90% of Project ECHO-Pediatrics participants experienced increased confidence. Overall, there was an improvement in participants’ self-efficacy in the post-training compared to the pre-training (range 14.7%-22.6% difference from pre-training). All participants improved on their results in the clinical test immediately after the training and maintained it after 3 months. The study demonstrated the ability Project ECHO to improve healthcare worker knowledge and satisfaction.

Using various chromatographic separations, four compounds, including one new steroid saponin named vernoamyoside E (1), were isolated from the leaves of the Vietnamese medicinal plant Vernonia amygdalina Delile (Asteraceae). Their structures were established by spectroscopic methods such as 1D- and 2D-NMR, HR-ESI-MS, and HPLC analysis. The inhibitory activities against α-glucosidase and α-amylase of the isolated compounds from V. amygdalina were reported for the first time. The results indicated that compound 1 significantly inhibited both against α-amylase and α-glucosidase activity.

The pathogenic fungi often cause huge impacts on agricultural crops, and occupy over 80% of plant diseases. Fusarium oxysporum and Rhizoctonia solani are fungal pathogens that can lead to rapid development of plant diseases on important crops in Tay Nguyen (e.g., pepper, coffee, rubber, cashew). Therefore, the study of microorganisms with bioactivity against these pathogens is essential to control plant diseases. In this study, we isolated microorganisms from rhizospheres of pepper in Tay Nguyen and screened beneficial microbes against two pathogenic fungi using agar well diffusion assay. Obtained results showed that there are different about isolated microbial density between samples collected from diseased and healthy pepper. The bacterial population is higher in rhizosphere region of healthy pepper than in those of diseased plants. In contrast, fungal density is lower in rhizosphere region of healthy plants than in those of diseased ones. From isolation plates, we selected and purified 391 strains including 236 bacteria, 149 actinomycetes and 6 fungi for screening antifungal activity. Out of isolated microorganisms, 44 strains (36 bacteria, 6 actinomycetes, and 2 fungi) showed antagonistic activity against at least one of two pathogens (F. oxysporum and R. solani), of which 15 isolates showed activity against both fungi. Identification of isolates with highest activity using the 16S rRNA gene sequences showed bacterial strains belonged to different species Enterobacter ludwigii, Pseudomonas fulva, Bacillus subtilis, whereas 2 actinomycetes belonged to the genus Streptomyces: Streptomyces sp. and Streptomyces diastatochromogenes. Identification of the isolated fungus based on morphological characteristics and the 18S rRNA gene sequence revealed that this strain belonged to species Penicillium oxalicum. Our study revealed the potential of the indigenous microorganisms in preventing and controlling plant-pathogenic fungi.

This study aimed to assess the diversity and antimicrobial activity of cultivable bacteria associated with Vietnamese sponges. In total, 460 bacterial isolates were obtained from 18 marine sponges. Of these, 58.3% belonged to Proteobacteria, 16.5% to Actinobacteria, 18.0% to Firmicutes, and 7.2% to Bacteroidetes. At the genus level, isolated strains belonged to 55 genera, of which several genera, such as Bacillus, Pseudovibrio, Ruegeria, Vibrio, and Streptomyces, were the most predominant. Culture media influenced the cultivable bacterial composition, whereas, from different sponge species, similar cultivable bacteria were recovered. Interestingly, there was little overlap of bacterial composition associated with sponges when the taxa isolated were compared to cultivation-independent data. Subsequent antimicrobial assays showed that 90 isolated strains exhibited antimicrobial activity against at least one of seven indicator microorganisms. From the culture broth of the isolated strain with the strongest activity (Bacillus sp. M1_CRV_171), four secondary metabolites were isolated and identified, including cyclo(L-Pro-L-Tyr) (1), macrolactin A (2), macrolactin H (3), and 15,17-epoxy-16-hydroxy macrolactin A (4). Of these, compounds 2-4 exhibited antimicrobial activity against a broad spectrum of reference microorganisms.

Sponges (Phylum Porifera) are ancient sedentary and filter-feeding animals which harbour very diverse and abundant associated microbial community in their tissues with density up to 40–50% of sponge tissue volume. In this study, the diversity of associated microorganisms with two marine sponges Haliclona oculata and Amphius huxleyi collected at the Lang Co bay of Vietnam was assessed by analysis of hypervariable V3 and V4 regions of the 16S rRNA gene using Illumina MiSeq system. The taxonomic diversity of sponge-associated microorganisms was classified to different taxonomic levels (kingdom, phylum, class, order, family, and genus). Based on Bayesian classification method and reference sequences derived from Greengenes database, the associated microorganisms in studied sponges were assigned to 17 phyla (H. oculata) and 13 phyla (A. huxleyi). Many microbial taxa were detected in two sponge species, however, they were distinctive by the abundance. Proteobacteria was the most dominant phylum in both sponge species, and all of 4 classes Epsilonproteobacteria, Gammaproteobacteria, Alphaproteobacteria, and Deltaproteobacteria were found in H. oculata and A. huxleyi.

A comprehensive phytochemical investigation of the dichloromethane-soluble fraction of Physalis angulata led to the isolation of eight compounds (1–8) including two new withanolides named physagulin P and Q (compounds 5 and 8). Their chemical structures were established using two-dimensional nuclear magnetic resonance (spectroscopy. The cytotoxic activity of these metabolites was investigated against A549, HeLa, and PANC-1 cancer cell lines. Among them, compound 1 showed significant cytotoxic activity against A549 cells with a half-maximal inhibitory concentration (IC50) value of 8.27 μM, while compound 7 showed the most potent activity against PANC-1 cells with an IC50 value of 3.18 μM.

Marine sponge is known as a “gold mine” of natural products from marine environment. Many novel bioactive compounds have been isolated from marine sponges and sponge-associated microorganisms such as antibiotics, anti-cancer compounds, protease inhibitors, etc. In this study, we selected a gene encoding protease inhibitor from metagenome of a sponge collected in Da Nang to express in Escherichia coli BL21(DE3). The gene PI-DN9 encoding protease inhibitor (1.3 kb) was cut off cloning vector pUC57/PI-DN9 containing gene PI-DN9 and inserted into expression vector pET32a(+), the recombinant vector pET32a(+)/PI-DN9 then was transformed and expressed in the E. coli strain BL21(DE3). Results showed that recombinant protein (50 kDa) was expressed successfully at 25°C, 1 mM of IPTG in 5 hours. The recombinant protein was purified using Ni-NTA affinity chromatography column. Western blot assay and bioactive assay showed good activity of the purified protein.

Let A1 be any spectrum in a class of finite spectra whose mod-2 cohomology is isomorphic to a free module of rank one over the subalgebra A(1) of the Steenrod algebra. Let EC be the second Morava-E theory associated to a universal deformation of the formal completion of the supersingular elliptic curve (C) : y2+y = x3 defined over F4 and S1C a certain closed subgroup of the Morava stabiliser group. As first steps towards understanding the homotopy type of the K(2)-localisation of the 2-local sphere spectrum, we analyse, in this thesis, the topological duality spectral sequence for EChS^1_C ^A1[symbol dollar], constructed by Irina Bobkova and Paul Goerss. In particular, we compute the E1-term of the latter and prove that its edge homomorphism is surjective.; Soit A1 un spectre dans une classe des spectres finis dont la cohomologie modulo 2 est isomorphe à un module libre de rang un sur la sous-algèbre A(1) de l'algèbre de Steenrod. Soit EC la seconde E-théorie de Morava associée à une déformation universelle de la complétion formelle de la courbe elliptique supersingulière (C) : y2+y = x3 définie sur F4 et S1C un certain sous-groupe fermé du groupe des stabilisateurs de Morava. Dans la perspective de mieux comprendre le type d'homotopie de la localisation en K(2) du spectre des sphères 2-local, nous analysons, dans cette thèse, la suite spectrale de dualité topologique pour EChS^1_C ^A1, construite par Irina Bobkova and Paul Goerss. En particulier, nous calculons le term E1 de la dernière et montre que son application du bord est surjective.

INTRODUCTION AND AIMS: Gender and age patterns of drinking are important in guiding country responses to harmful use of alcohol. This study undertook cross-country analysis of drinking across gender, age groups in some high-and middle-income countries. DESIGN AND METHODS: Surveys of drinkers were conducted in Australia, England, Scotland, New Zealand, St Kitts and Nevis (high-income), Thailand, South Africa, Mongolia and Vietnam (middle-income) as part of the International Alcohol Control Study. Drinking pattern measures were high-frequency, heavier-typical quantity and higher-risk drinking. Differences in the drinking patterns across age and gender groups were calculated. Logistic regression models were applied including a measure of country-level income. RESULTS: Percentages of high-frequency, heavier-typical quantity and higher-risk drinking were greater among men than in women in all countries. Older age was associated with drinking more frequently but smaller typical quantities especially in high-income countries. Middle-income countries overall showed less frequent but heavier typical quantities; however, the lower frequencies meant the percentages of higher risk drinkers were lower overall compared with high-income countries (with the exception of South Africa). DISCUSSION AND CONCLUSIONS: High-frequency drinking was greater in high-income countries, particularly in older age groups. Middle-income countries overall showed less frequent drinking but heavier typical quantities. As alcohol use becomes more normalised as a result of the expansion of commercial alcohol it is likely frequency of drinking will increase with a likelihood of greater numbers drinking at higher risk levels.

Introduction and Aims To investigate behaviours related to four alcohol policy variables (policy-relevant behaviours) and demographic variables in relation to typical quantities of alcohol consumed on-premise in six International Alcohol Control study countries. Design and Methods General population surveys with drinkers using a comparable survey instrument and data analysed using path analysis in an overall model and for each country. Measures: typical quantities per occasion consumed on-premise; gender, age; years of education, prices paid, time of purchase, time to access alcohol and liking for alcohol advertisements. Results In the overall model younger people, males and those with fewer years of education consumed larger typical quantities. Overall lower prices paid, later time of purchase and liking for alcohol ads predicted consuming larger typical quantities; this was found in the high-income countries, less consistently in the high-middle-income countries and not in the low middle-income country. Three policy-relevant behaviours (prices paid, time of purchase, liking for alcohol ads) mediated the relationships between age, gender, education and consumption in high-income countries. Discussion and Conclusions International Alcohol Control survey data showed a relationship between policy-relevant behaviours and typical quantities consumed and support the likely effect of policy change (trading hours, price and restrictions on marketing) on heavier drinking. The path analysis also revealed policy-relevant behaviours were significant mediating variables between the effect of age, gender and educational status on consumption. However, this relationship is clearest in high-income countries. Further research is required to understand better how circumstances in low-middle-income countries impact effects of policies.

Introduction and Aims This study examines the proportion of alcohol markets consumed in harmful drinking occasions in a range of high-, middle-income countries and assesses the implications of these findings for conflict of interest between alcohol producers and public health and the appropriate role of the alcohol industry in alcohol policy space. Design and Methods Cross-sectional surveys were conducted in 10 countries as part of the International Alcohol Control study. Alcohol consumption was measured using location- and beverage-specific measures. A level of consumption defined as harmful use of alcohol was chosen and the proportion of the total market consumed in these drinking occasions was calculated for both commercial and informal alcohol. Results In all countries, sizeable proportions of the alcohol market were consumed during harmful drinking occasions. In general, a higher proportion of alcohol was consumed in harmful drinking occasions by respondents in the middle-income countries than respondents in the high-income countries. The proportion of informal alcohol consumed in harmful drinking occasions was lower than commercial alcohol. Discussion and Conclusions Informal alcohol is less likely to be consumed in harmful drinking occasions compared with commercial alcohol. The proportion of commercial alcohol consumed in harmful drinking occasions in a range of alcohol markets shows the reliance of the transnational alcohol corporations on harmful alcohol use. This reliance underpins industry lobbying against effective policy and support for ineffective approaches. The conflict of interest between the alcohol industry and public health requires their exclusion from the alcohol policy space.

Introduction and Aim: To report data on the implementation of alcohol policies regarding availability and marketing, and drink driving, along with ratings of enforcement from two small high-income to three high-middle income countries, and one low-middle income country. Method: This study uses the Alcohol Environment Protocol, an International Alcohol Control study research tool, which documents the alcohol policy environment by standardised collection of data from administrative sources, observational studies and interviews with key informants to allow for cross-country comparison and change over time. Results: All countries showed adoption to varying extents of key effective policy approaches outlined in the World Health Organization Global Strategy to Reduce the Harmful Use of Alcohol (2010). High-income countries were more likely to allocate resources to enforcement. However, where enforcement and implementation were high, policy on availability was fairly liberal. Key Informants judged alcohol to be very available in both high- and middle-income countries, reflecting liberal policy in the former and less implementation and enforcement and informal (unlicensed) sale of alcohol in the latter. Marketing was largely unrestricted in all countries and while drink-driving legislation was in place, it was less well enforced in middle-income countries. Conclusion: In countries with fewer resources, alcohol policies are less effective because of lack of implementation and enforcement and, in the case of marketing, lack of regulation. This has implications for the increase in consumption taking place as a result of the expanding distribution and marketing of commercial alcohol and consequent increases in alcohol-related harm. © 2018 The Authors Drug and Alcohol Review published by John Wiley & Sons Australia, Ltd on behalf of Australasian Professional Society on Alcohol and other Drugs

A 2010 World Health Assembly resolution called on member states to intensify efforts to address alcohol-related harm. Progress has been slow. This study aims to determine the magnitude of public support for 12 alcohol policies and whether it differs by country, demographic factors and drinking risk (volume consumed).

Introduction Taxation is increasingly being used as an effective means of influencing behaviour in relation to harmful products. In this paper we use data from six participating countries of the International Alcohol Control Study to examine and evaluate their comparative prices and tax regimes. Methods We calculate taxes and prices for three high-income and three middle-income countries. The data are drawn from the International Alcohol Control survey and from the Alcohol Environment Protocol. Tax systems are described and then the rates of tax on key products presented. Comparisons are made using the Purchasing Power Parity rates. The price and purchase data from each country's International Alcohol Control survey is then used to calculate the mean percentage of retail price paid in tax weighted by actual consumption. Results Both ad valorem and specific per unit of alcohol taxation systems are represented among the six countries. The prices differ widely between countries even though presented in terms of Purchasing Power Parity. The percentage of tax in the final price also varies widely but is much lower than the 75% set by the World Health Organization as a goal for tobacco tax. Conclusion There is considerable variation in tax systems and prices across countries. There is scope to increase taxation and this analysis provides comparable data, including the percentage of tax in final price, from some middle and high-income countries for consideration in policy discussion.

Using metagenomics-based method to isolate new compounds from the marine environment are getting more and more attention in recent years. Based on metagenome library, bioinformatics methods is a powerful tool for screening genes with new biological activities from uncultured microorganisms and become a breakthrough in research and application of biotechnology. In this study we selected and used the samples DNA QT2 which had high DNA content and purity from a total of 6 DNA samples of sponge-associated microorganisms collected in Quang Tri sea (Vietnam) for metagenomic sequencing (DNA concentration is 202.5 ng, A260/ A280 value is 1.80). 16S rRNA metagenomic sequencing data of QT2 produced 44,117,722 reads, which were assembled into 120,236 contigs. ORF prediction using Prodigal produced 386,416 ORFs. Functional annotation was conducted based on 7 different databases (NR, COG, CAZy, Swissprot, GO, KEGG, Pfam), and there are 266,553 genes were annotated using Swiss-Prot. In addition, based on the obtained metagenomic data, 50 complete genes encoding protease inhibitor proteins were revealed and among them, 28 genes encoding protein (> 50%) belonged to the serine protease inhibitor family, and 22 genes genes encoding belonged to the Inter-alpha-trypsin inhibitor group. NCBI BLAST screening results that these proteins had higher 50% identity to protease inhibitors.