Vietnam Academy of Science and Technology: Journals Online
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EFFECTS OF SALT STRESS ON PLANT GROWTH AND BIOMASS ALLOCATION IN SOME WETLAND GRASS SPECIES IN THE MEKONG DELTA
Full text linkSalt stress causes serious damage to many cellular and physiological processes that leads to yield reduction. The study induced salt stress using Hoagland solution added NaCl to evaluate its effects on plant growth and biomass allocation of some wetland grass species in order to identify salt-tolerant species for replacing and/or supplementing rice/grass in rice-shrimp model and salt-affected area in the Mekong Delta. The study also seeks to evaluate the response of leaf chlorophyll (SPAD unit) and proline content in salt-treated plants to varying application of salinity. Typha orientalis, Lepironia articulata, Eleocharis dulcis and Scirpus littoralis were studied in hydroponics condition with four levels of NaCl of 5, 10, 15, 20‰ and the control treatment (without adding NaCl). The experiment was arranged in a completely randomized design with 3 replications. The salt-treated plants showed visually clear responses of inhibited growth under salt stress condition compared to the control plants. Among the four studied species, T. orientalis produced the highest dry shoot biomass (15.5 g DW/plant), while E. dulcis had the lowest value (2.8 g DW/plant). However, only T. orientalis showed significantly decreased in biomass as salinity increased with 9.3 and 4.6 times lower of fresh and dry biomass in plants grown at the salinity level of 20‰ compared to those grown in the control treatment. The other three plant species did not affect by salinity levels. The results indicated that S. littoralis, L. articulata and E. dulcis could tolerate at high salinity of 20‰ (eq. to the EC value in the nutrient solution of 38.0 dS/m) and could be potential candidate to grow in the rice-shrimp model or in the salt-affected soils.
STUDY ON THE REMOVAL OF AMMONIA IN WASTEWATER USING ADSORBENT PREPARED FROM RICE HULL WITH MAGNESIUM OXIDE MODIFICATION
No full textThis study is aimed to evaluate the ability of magnesium oxide-coated carbonized rice hull (MCRH) material for ammonium removal in synthetic and real domestic wastewater. The MCRH material was prepared using waste rice hull from a household rice-processing factory and magnesium chloride salt via a simple mixing and annealing method. The material was then characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The effects of magnesium chloride modification and environmental condition such as initial ammonium concentration (20 – 100 mg/L), amount of adsorbent (0.8 –2.0 g/L), and adsorption time (0 –32 h) on the ammonium removal efficiency and adsorption capacity were investigated. Adsorption kinetic and isotherms were also studied for MCRH material. Results showed that magnesium oxide was successfully coated on carbonized rice hull with Mg/C molar ratio of 0.22. Ammonium adsorption isotherm fitted well to Langmuir model with maximum adsorption capacity of 65.36 mg/g. The adsorption was physical process and adsorption kinetic was best described by intra-particle diffusion model with the correlation coefficients ranged from 0.942 – 0.979. Ammonium removal feasibility of MCRH was proved through the treatment of real domestic wastewater containing 80.7±1.6 mg/L initial ammonia concentration with removal efficiency reached 86.8% and the effluent concentration met the allowable value (10 mg/L) as given by QCVN 14 : 2008/BTNMT (column B) - National technical regulation on domestic wastewater. Hence MCRH is potential as a cheap and abundant material in Vietnam and the material after adsorption accumulated ammonium would be the source of fertilizer for soil quality improvement
Quantitative analysis of Caffeine in the leaves and flowers of Camellia chrysantha by high-performance liquid chromatography with DAD detection
No full textCaffeine (1,3,7-trimethylxanthine) is the active alkaloid component which is a naturally occurring substance found in the leaves, seeds or fruits of over 63 plants species worldwide. Although caffeine intoxications are rare, they prove the toxic potential of this common constituent, resulting the tachycardia, atrial arrhythmias, convulsions or even coma. Caffeine toxic effect is increased when taken with other medicines, because it is metabolized through the cytochrome P450 system – primarily by the isoenzyme cYP1A2. This enzyme is also inhibited by antipsychotics and antiarrhythmic drugs, which could become toxic in presence of caffeine. This paper describes the methods for qualitative and quantitative determination of caffeine by HPLC. The results present optimal conditions for the rapid analysis of caffeine with high precision and accuracy which is suitable for its determination in the plant. The obtained results revealed that no caffeine is detected in the leaves and flowers of golden camellia (Camellia thrysantha). Thus, we may suggest that taking of golden camellia leaves and flowers as natural alternative to current decaffeinated tea could be avoid some unwanted side effects that caffeine produced beside the antioxidant content and health benefits of the plant material
Anomalous Magnetic Dipole Moment in 3-3-1 Model with Inverse Seesaw Neutrinos
Full text linkWe will show that the recent experimental value of the anomalous magnetic moment (AMM) of the charged lepton m , denoted as , can be explained successfully in a 3-3-1 model with right handed neutrino adding new heavy neutrinos singlets. Allowed regions satisfying the recent AMM data are illustrated numerically
Diversity of the genus Sargassum (Fucales: Sargassaceae) in Tho Chu Archipelago, Kien Giang Province.
Full text linkOur study investigated 12 study sites in four main islands of Tho Chu archipelago in 2019. Six Sargassum species were recorded for the flora of Tho Chu Archipelago, viz.Sargassum aquifolium (Turner) C.Agardh, Sargassum feldmannii Pham-Hoang Ho, Sargassum ilicifolium (Turner) C.Agardh, Sargassum mcclurei Setchell, Sargassum oligocystum Montagne, Sargassum polycystum C.Agardh, among which three species, namely Sargassum oligocystum Montagne, Sargassum feldmannii Pham-Hoang Ho and Sargassum mcclurei Setchell were newly recorded for Vietnam. There was a significant difference in species composition between Tho Chu, Hon Xanh, Hon Tu and Hon Cao islands; among them, Hon Xanh island differed from the other three islands by 28%, Hon Tu island and Tho Chu island were mostly similarity in flora composition with the similarity index of 85.7%. The morphology of some Sargassum species varied by ecological characteristics, especially for Sargassum aquifolium (Turner) C. Agardh and Sargassum oligocystum Montagne.
Antimicrobial activity of natural compounds from sponge – derived fungus Aspergillus flocculosus 01NT.1.1.5
Full text linkThe Aspergillus fungi have been an important source of natural products that are useful for exploration in medicine, agriculture and industry. In our continuous investigation to search for new antimicrobial agents from marine-derived fungi, one new phomaligol A2 (1), together with three known compounds, wasabidienone E (2), aspertetranone D (3) and mactanamide (4), were obtained from the EtOAc extract of the culture medium of the marine-derived fungus Aspergillus flocculosus (A. flocculosus) 01NT.1.1.5 isolated from the sponge Stylissa sp. at Nhatrang Bay, Vietnam. Their chemical structures were elucidated by analysis of 1D and 2D NMR and mass spectroscopic data, as well as by comparison of the corresponding data to those previously reported in the literature. Furthermore, the aim of this study was also to evaluate the antimicrobial activity of these compounds against pathogenic microbes including Escherichia coli (E. coli) ATCC 25922, Pseudomonas aeruginosa (P. aeruginosa) ATCC 27853, Staphylococcus aureus (S. aureus) ATCC 25923, Bacillus cereus (B. cereus) ATCC 11778, Streptococcus faecalis (S. faecalis) ATCC 19433, Listeria monocytogenes (L. monocytogenes) ATCC 19111, and Candida albicans (C. albicans) ATCC 10231. Among the compounds, 1-3 were inhibitory on the growth of the yeast C. albicans with minimum inhibitory concentration (MIC) value of 16 μg/mL, which was more potent than amoxicillin and cefotaxime (MIC 256 μg/mL), antimicrobial drugs as positive references. Moreover, compounds 1-4 were also found to be active against other pathogens including P. aeruginosa and S. faecalis with MIC values of 16 μg/mL and 32 μg/mL, respectively. Compound 4 had no inhibitory activity against L. monocytogenes, whereas compounds 1-3 had ability to against this strain with MICs of 32 to 64 μg/mL. Four of tested compounds exhibited antibacterial activity against B. cereus and E. coli with MIC values of 64-128 μg/mL. This is the first report about these compounds with antimicrobial activity obtained from marine fungus A. flocculosus isolated in Vietnam
Effect of plant growth regulators on growth and lipid accumulation of microalgal Haematococcus pluvialis Flotow in two-stage culture
Full text linkHaematococcus pluvialis cells were cultured in aerated liquid Bold’s Basal medium in two-stage (initial stage during in 7 weeks for increased biomass growth and second stage during in 3 weeks for increased lipid accumulation) with different volumes 250 mL, 10 L, and 1,000 L. With a volume of 250 mL, the medium was supplied with benzyl adenine (BA), indole-3-acetic acid (IAA) or gibberellic acid (GA3) at concentration from 0.1 - 0.2 mg/L in initial stage and IAA or GA3 at concentration from 0.1 - 0.2 mg/L in second stage. After 10 weeks of culture, results showed that supplement of 0.1 mg/L BA in initial stage and 0.125 mg/L IAA in second stage increased cell density, and microalgal cells had green color with a spherical shape. On the contrary, supplement of 0.15 mg/L IAA in initial stage and 0.175 mg/L GA3 in second stage increased lipid accumulation, and microalgal cells had red color with a spherical shape. With a volume of 10 L, the medium was supplied with 0.1 mg/L BA in initial stage, and treated with separation or combination from 2 - 3 of these factors (nitrogen starvation, 0.5% NaCl, 4.98 mg/L FeSO4) were applied in second stage. The result showed that the cultures was treated with nitrogen starvation increased dry biomass and biofuel, but treated with 4.98 mg/L FeSO4 only increased biofuel. With a volume of 1,000 L, microalgal cells were cultured in BB liquid medium in initial stage, and treated with 4.98 mg/L FeSO4 increased fresh 78.67 mg/mL and dry biomass 2.05 mg/L and total lipid content 28.24 %/ DW
Human-elephant conflict in Pu Mat National Park region, Nghe An Province: current status and impact on the conservation atitude of local residents
No full textPu Mat National Park (NP) region is designated by the Government of Vietnam as a priory area for conservation of the Asian elephant. Out of three elephant groups currently inhabited Pu Mat NP region, only the group in Anh Son District (Anh Son elephant group) causes severe human-elephant conflict (HEC) with significant economic damage for local villagers and rubber farms, human casualties, and induced psychological pressure for local residents. Because of the HEC, support for the elephant conservation of local residents was significantly reduced and the retaliatory killing of an elephant happened in 2011.This study assessed the HEC status in Anh Son District and identified the main causes of HEC here.
Protection of chickens against A/H5N1 virus by plant-based haemagglutinin fused IGMFC
No full textVaccination is one of the most effective and cost-beneficial interventions for protection of animals against the highly pathogenic A/H5N1 avian influenza virus. Haemagglutinin (HA) is a transmembrane glycoprotein of A/H5N1 virus and is a critical antigen for development of the influenza vaccine. The haemagglutinin-based vaccine produced in plants was demonstrated as a candidate vaccine since it elicited neutralizing antibodies against A/H5N1 virus. In this study, immunogenicity and protective ability of a plant-based recombinant HA antigen which was fused to IgMFc to form oligomerized HA antigen (H5TG oligomer) had been evaluated by vaccination in chickens. Chicken sera after each vaccination were collected for Western blot, ELISA and HI assays. Ten days after the second vaccination, the chickens have been challenged with A/duck/TG/NAVET(3)/2013 virus, clade 1.1. The analysis results showed that the oligomeric recombinant H5TG antigen elicited stronger H5TG-specific IgY antibodies and A/H5N1 clade 1.1 virus-neutralizing antibodies than the H5TGpII trimeric recombinant antigen without fusing IgMFc in vaccinated chickens. Notably, the chicken protection rate against A/H5N1 clade 1.1 virus of the H5TG oligomer antigen was 80% that is not significantly lower than that of a commercial vaccine as a positive control from National Veterinary Joint Stock company NAVETCO, Vietnam with the chicken protective rate of 90%. Whereas the chicken protection rate against A/H5N1 clade 1.1 virus of the H5TG trimer antigen was 50%. These results suggest that the IgMFc motif plays an important role in the forming of oligomeric proteins which had been proved for enhancing immunogenicity and protection ability in this study. Therefore, the plant-based oligomerized recombinant H5TG antigen is a potential vaccine candidate against A/H5N1 influenza virus in the future