Trường Đại học Khoa học Tự nhiên, Đại học Quốc gia Thành phố Hồ Chí Minh

This study presented simulation results of runoff discharge combining the Mike NAM and Mike SHE models for lower Sai Gon-Dong Nai River basin (SG-DNRB). Sai Gon-Dong Nai River basin is Vietnam’s largest population center and main industrial area in Ho Chi Minh City. In recent years, the area faces flooding problems because of heavy rainfalls and high tides, as part of the impacts of climate change and sea level rise. The lower of SG-DNRB was selected as a case study to highlight the necessity to investigate combination of the rainfall–runoff model and the hydrodynamic model for long-term strategies to resource water in the future. The models were calibrated using water level and runoff discharge data during low and flood seasons in 2014. The calibrated results showed satisfactory coefficients (NASH index, R2 up to 0.70 and RMSE is smaller than 0.20). The results confirmed that the combination of Mike NAM and Mike SHE models is well suitable to simulate runoff discharge in the lower SG-DNRB. Combination of the models can be considered a useful tool to help professional agency operator water resources management projects in other areas in the context of climate change and sea level rise.

Nitrate content (NO3-) is one of the important indicators to assess the quality of leafy vegetables. Many studies have shown that vegetables in local markets containing high levels of nitrate that induce harmful effects on human health. In Vietnam, publications on the correlation between NO3-/+NH4 ratio and the nitrate accumulation are limited. Mustard green (Brassica juncea L.) is a popular vegetable and has a high nutrient (rich in fiber and micronutrients). However, the effect of nitrogen on the nitrate accumulation by hydroponic has not been elucidated. In this study, mustard green was grown in four media with different NO3-/+NH4 ratios (2/1; 1.5/1; 3/1, and 4/0) in the hydroponic reflux system. Results showed that the nitrogen requirement of mustard green depended on growth stages. Mustard green needed a low NO3-/+NH4 ratio at the slow growth stage (seedlings) and a high NO3-/+NH4 ratio at the fast one. In addition, the increase of the nitrate content also improved the chlorophyll content in the leaves. The complete removal of +NH4 in the medium stimulated the nitrate accumulation in leaves. The study showed that the suitable hydroponic medium for mustard green was MS medium supplemented with twice KNO3. The KNO3 addition in the hydroponic medium increased the chlorophyll content, the fresh weight, and ensured the content of nitrate (417.59 ± 10.51 mg/kg) within the allowable limits (< 500 mg/kg).

Introduction: To date, there have been many studies indicating the positive effects of stem cells on treating liver cirrhosis. In this study, we used umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) for treatment in a mouse model of liver cirrhosis. Specifically, we determined and compared the effectiveness of two methods of MSC injection (tail vein versus portal vein). Methods: Liver cirrhosis in male Swiss mice (of age approximately 11 weeks or under) was induced by administration of carbon tetrachloride (CCl4; 1 ml/kg). One million UCB-MSCs were then transplanted into cirrhotic mice via the portal vein or tail vein. After 21 days, blood samples were collected for measurement of transaminase, bilirubin and albumin. The expression of fibrosis-associated genes, specifically procollagen – alpha 1 and integrin – beta1, were assessed using quantitative RT-PCR. The histopathology of the specimens was also evaluated using hematoxylin/eosin, Masson trichrome staining, and immunohistochemistry using collagen type 1 and alpha-SMA antibodies. Results: After 21 days, cirrhotic mice treated with UCB-MSCs showed recovery of bilirubin index, increase of liver albumin synthesis, inhibition of fibrosis-related gene expression (e.g. procollagen – alpha 1 and integrin – beta1), and remodeling of liver histology. From comparison of the different routes of transplantation, UCB-portal route was significantly more effective than UCB-tail route at reducing aspartate transaminase (AST) activity and bilirubin index (P<0.05), and inhibiting procollagen – alpha 1 and integrin – beta1 expression (P<0.05). UCB-MSCs from both transfusion routes showed accelerated improvement of liver histopathology. Conclusion: Therapeutic strategies using UCB-MSCs have proven to be promising for the treatment of liver cirrhosis. Injection of UCB-MSC via portal vein was more effective than tail vein for cirrhosis treatment.  

Investing in the biodiversity conservation along river catchments is a cost-effective nature-based solution to ensure the availability and sustainable management of water and the richness of biodiversity for all, with many co-benefits for the other sustainable development goals. The need for further exploration and conservation assessments of inland freshwater fish fauna coincides with expanding threats to freshwater resources from flow alteration and water diversion, increased sediment load, introduced species, overfishing and habitat loss. Meanwhile, the discipline approaches of former studies on the taxonomy of freshwater fish fauna of the Sai Gon - Dong Nai rivers and adjacent drainage basins were ambiguous and no information on phylogenetic relationships and geographic distribution. Our surveys from 2010 to 2020 on revising the fish fauna provided their phylogenetic relationship and geographic distribution. The evolutionary and phylogenetic relationships were analyzed for fish species by using several mitochondrial and nuclear genomes such as COI, Cyto b, 16S rRNA, ATPase 6-8, RAG1, and delineated factors of fish distribution were also inferred. A total of 243 indigenous species, belonging to 166 genera, 79 families, 28 orders were identified from 861 specimens collected in 19 sampling sites. This study updated the scientific names with the correction of three species, determined the phylogenetic relationship, and endemism were integrated from this study and modified global fish phylogenetic data. Based on their zoogeography, the studied fishes were subgrouped into five units, among them, 156 primary species shared with the ones of Mekong river (65 with the Sundaland), one with the Red river, 81 with the Indo - Western Pacific sea and five endemic species. The Sai Gon - Dong Nai rivers and adjacent drainage basins possessed only five endemic species, withholding 3% of the total studied primary species. The mentioned-drainage basins, perhaps in the Quaternary were partly formed from the paleo Mekong Delta, shared with most of primary species (about 96%) of the Mekong river. The Mekong Delta freshwater ecoregion was proposed including most of southern coastal drainage basins of the southern Vietnam.

Introduction: Bisphenol A (BPA) is used in synthesis of plastics. It is known as a potential chemical that causes hormonal changes in human and animals. Many previously studies showed that the activity of BPA was similar to estrogen and it could affect on embryonic and newborn stages. From a different approach, a research by these authors published in 2017 suggested that BPA could effect to the fast- growing stage of an animal based on proteomic profiles of Juvenile-stage zebrafish livers long term exposured to mg/L range of the chemical. This study was the extent of that research to further investigate which metabolic receptors in liver effected by BPA exposure. Among suggestedhepatic receptors, PPARg and C/EBPa genes may be targeted by BPA under such exposure condition. Methods: In this study, zebrafish at 30th day of age were exposed to 0, 10 and 100 mg /L BPA, respectively, and continuously for 60 days under a standar condition for testing chronic toxicity of a chemical on fish. At the end of the testing, mRNA levels of PPARg and C/EBPa genes in zebrafish livers of BPA-exposed groups were compared to that of BPA-unexposed group using Real-Time PCR method with b -actin gene as the reference gene. Results: BPA affected transcription level of both genes depending on the concentration of the chemical. Reduction of 67% and 70% on mRNA level for PPARg and C/EBPa, respectively, was only observed on 100 mg/L BPA-exposed group. No significant change on such regulation was found in 10 mg/L BPA-exposed group. Conclusion: Thus, the effect of BPA exposure on liver functions of zebrafish at juvenile stage may associate with hepatic PPARg and C/EBPa receptors and it depends on the chemical concentration.  

Chrysanthemum indicum cultivar Sakura is one of the daisy cultivars. It is beautiful, but the vase life of cutting flowers is very short. The decrease in flower quality during storage and transportation is a big problem in the flower export. In this study, the morphological, physiological, and biochemical changes during the vase life of cutting flowers were analyzed. The effects of plant growth regulators and sucrose at different concentrations on the vase life of cut flowers were investigated. The vase life of Sakura cutting flowers includes two stages: (1) the growing and blooming of flower, (2) senescence of cutting flowers. During the growing and blooming, the color of disk flowers changed from green to yellow, and the ray flowers continued to expand the dimension leading to an increase in the diameter of the head flower. The senescence of cutting flowers was initiated by the reduction of chlorophyll content in the leaf, which was located at the base. Then, the ray flowers were discolored. In the senescence stage, the respiration rate and the content of the abscisic acid of head flower increased continuously. In contrast, the water absorption, the content of starch, total sugar, salicylic acid, auxin, cytokinin, and gibberellin decreased strongly. The treatment of 10 g/L sucrose, 2 mg/L NAA, 5 mg/L BA, and 20 mg/L salicylic acid in 24 hours extended the vase life of Sakura cutting flowers and the diameter of the head flower.  

Yacon (Smallanthus sonchifolius), a plant traditionally grown in the Northern and Central Andes, is recently cultivated in Vietnam. The edible storage roots of yacon contain a large amount of carbohydrate during the form of indigestible fructooligosaccharide (FOS), which functions as a prebiotic and gives positive effect during the treatment of obesity, diabetes, and colorectal cancer. Thus, yacon root is expected to be a good dietary supplement for patients with these diseases. There has been limited research about the impacts of microorganisms on the tuberous root formation of yacon. Therefore, this paper presents the enumeration of aerobic bacteria in the root area at the two growing stages, before and in the early stage of the tuberous root formation, of yacon by MPN (Most Probable Number) method. The obtained results show a significant change on the amount carbohydrate metabolism bacteria presence in yacon roots between the two growing stages. Besides, there are more carbohydrate metabolism bacteria (9,3 x 105 MPN/mL) in tuberous root than protein metabolism bacteria (9,3x103 MPN/mL). The isolation of aerial bacteria from yacon roots found 22 strains, which are assigned into the 10 genera including Burkholderia, Caulobacter, Myroides, Pantoea, Pseudomonas, Stenotrophomonas, Kosakonia, Rhizobium, Enterobacter, and Klebsiella based on the phylogentic analysis of the so-called 800R 16S rRNA gene sequences. The appearance of those genera in difference parts of yacon root is not the same. The presence of difference genera is also shown in the roots at the two growing stages.

Introduction: Adipose-derived stem cells (ADSCs) are considered as mesenchymal stem cells (MSCs). Indeed, they display all characteristics of MSCs that compliant with the minimal criteria of MSCs suggested by Domonici et al. (2006). However, some recent studies showed that ADSCs contain the subpopulation that was positive with CD34 marker – a marker of hematopoietic stem cells. This study aimed to analyze and determine the expression of CD34 marker in ten samples of ADSCs obtained from 10 donors. Methods: All ADSC samples were isolated and expanded according to the published previous protocols. They were confirmed as the MSCs with some markers and differentiation potential, excepting the CD34 expression. Then they were cultured and analyzed the expression of CD34 by flow cytometry at passage 3, 5, 7 and 9. Results: The results showed that expression of CD34 in ADSCs was different between donors and their passages that accounted from 1.21% to 23.38%. Conclusion: These results suggested that ADSCs are not ‘truly” MSCs like MSCs from bone marrow.

Tomato is one of the most popular foods in the world. However, drought stress has strongly decreased the growth and yield of tomatoes. Therefore, the study on drought-tolerant tomatoes is essential. In this paper, tomato cultivar TN704, which is popularly grown in Vietnam's Southeast and Vietnam's Mekong Delta was selected. The combination of auxin (IAA, indoleacetic acid) and cytokinin (zeatin) at different concentrations was investigated to determine the effective regeneration media. Then, the drought pretreatment was applied to obtain drought-tolerant shoots. The drought tolerance of regenerated shoots was checked by culture in the drought stress condition after two generations (F1 and F2). The physiological and biochemical changes of regenerated shoots in the drought stress condition were analyzed. The MS 1 2 medium supplemented with 0.2 mg/L IAA and 0.5 mg/L zeatin was the effective medium for in vitro shoot regeneration from tomato leaves. The drought pretreatment (MS 1 2 with 20 g/L mannitol) increased the number of regenerated shoots which can develop in the drought stress condition. The regenerated shoots in the F1 and F2 generations grew strongly under drought conditions. The content of chlorophyll, carotenoid and proline, the intensity of respiration and photosynthesis, and the activity of auxin and cytokinin in leaves of F1 and F2 plant were higher than the control.