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Gender equality is a human right. Women have the right to live worthy of dignity, to be able to do what they want, and not to be afraid. Gender equality is also a prerequisite for promoting development and reducing poverty. Empowered women improve the health and productivity of families and communities, creating solid prospects for future generations. In the past, in Vietnam, the issue of gender equality has been paid attention to by the state and created all conditions for gender equality to take place, however, in reality, gender equality still has some limitations. This study focuses on analyzing Vietnam’s gender equality policy, the issues raised, and then proposing solutions further to improve Vietnam’s gender equality policy in the future.

The attenuated porcine reproductive and respiratory syndrome virus (PRRSV) strain Hanvet1.vn was developed by Hanvet Pharmaceutical Co., Ltd. by inoculating the virulent strain 02HYon Marc-145 cells for 80 generations and used to produce PRRS vaccine. In this study, we published the results of sequencing, analyzing and comparing the genome of the attenuated PRRSV strain Hanvet1.vn compared with the original pathogenic strain 02HY. The genomes of strains Hanvet1.vn and 02HY have 8 reading frames, coding for 8 non-structural and structural proteins: NSP1a, NSP1b, GP2, GP3, GP4, GP5, MP, NP. After sequencing and translating into proteins, the gene sequence of each open reading frame (ORF) of strain Hanvet1.vn was compared with the sequence of pathogenic strain 02HY to find nucleotide and amino acid changes. The results showed that the Hanvet1.vn pathogenic strain genome (Genbank Accession KU842720) when compared with the pathogenic strain 02HY genome (Submission2490633) had89 nucleotide mutations that changed 51 amino acids in 7 ORFs and 7 proteins, respectively. Particularly, ORF6 encoding for the M protein is completely unchanged. The size of each reading frame is also exactly the same. It showed that there were no insertion and deletion (Indel) mutations in the ORFs of the attenuated strain after 80 generations of inoculation. There was a change in the genome that made the strain Hanvet1.vn become attenuated, but the gene encoding for the GP5 protein that induces the production of neutralizing antibodies only changed two nucleotides at position 471 (A->G), causing the TCA codon to turn into a TCG codon. This is a silent mutation and both codons code for the amino acid Serine (S). The second mutation at position 587 (A->T) causes Glutamine (Q) to transform into Leucine (L). However, this modification does not belong to the GP5 antigenic epitopes. In clonclusion, after 80 passages, despite changes occurred in genes of Hanvet1.vn strain for becoming an attenuated strain, the GP5 protein of the attenuated strain did not change its antigenic amino acids.

In this study, silver nanoparticles effects on the sterilization of different sources of explants (young leaves, young flower stalks and young flower buds) of Gerbera as well as on the in vitro morphogenesis and their growth were investigated. The explants were sterilized and cut transversally (1 mm) with the flower stalk, square (0.5 × 0.5 cm) for the leaf sample, longitudinally (0.5 mm) for the flowers (removed the petals) and cultured on MS medium; then, the explants (contamination-free or no browning/necrosis) were transferred into MS medium supplemented with 0.02 mg/L TDZ plus 0.8 mg/L adenine, 10% coconut water, 30 g/L sucrose and 8 g/L agar in 15 days. The results showed that AgNPs at the appropriate concentration and duration treatment was effective in explant sterilization of flower bud (0.02% AgNPs and 20 min), flower stalks (0.02% AgNPs and 30 min) and young leaves (0.05% AgNPs and 20 min) after 15 days of culture. In addition, 3 types of morphogenesis including callus induction, somatic embryogenesis and direct shoot regeneration of explants derived from sterilization by AgNPs were improved as compared to that of HgCl2. In addition, research on the optimal medium for shoot multiplication, rooting as well as evaluation of acclimatization and the growth at the greenhouse were also studied. Results showed that MS medium supplemented with 2 mg/L NAA combined with 0.5 mg/L BA and 2 mg/L KIN is suitable for shoot multiplication; meanwhile, MS medium supplemented with 2 mg/L NAA improved rooting ability as well as quality of plantlets and to improving survival rate and acclimatization of Gerbera cultured in vitro.

Many studies show that hyperglycemia can lead to injury to the intestinal mucosal barrier, increasing the likelihood of infection, leading to intestinal inflammation in people with type 2 diabetes. Recently, investigations indicate that the gut microbiome plays a very important role in this disease in which Lactobacillus in the gut has been shown to regulate glucose and lipid metabolism, improving oxidative stress, and inhibiting inflammatory responses. In this study, by the method of oriented isolation, the number of Lactobacillus bacteria in the subgroup of healthy people was determined to be (3,9 ± 1.2) x 103 CFU/g and in the group of diabetic patients was (2.7 ± 0.8) x 103 CFU/g. The study identified 17/68 selected Lactobacillus strains that were resistant to both Staphylococcus aureus ATCC13709 and Escherichia coli ATCC 11105. Moreover, these strains were also resistant to acid pH 2. Besides that, 16/17 strains tested were able to survive over 90% in 0.3% bile salt environment. Among the 17 strains studied, 3 strains of Lactobacillus 13, Lactobacillus 16, Lactobacillus 17 showed probiotic characteristics such as antibacterial ability, acid tolerance and bile salt tolerance. All three strains of Lactobacillus 13, Lactobacillus 16, and Lactobacillus 17 belong to species of Lactobacillus plantarum. This result makes a useful contribution to guide the application of Lactobacillus strain in creating dietary supplements for people with type 2 diabetes.

The growth of strawberry plantlets in the rooting stage on culture medium supplemented with silver nanoparticles (AgNPs) and the ethylene gas accumulation in plantlet culture bottles were investigated. In addition, different culture systems were first used to produce large-scale Strawberry plantlets. The results showed that shoots (3 cm) were cultured on MS medium supplemented with 0.02 mg/L NAA, 1 g/L activated charcoal, 30 g/L sucrose, 8 g/L agar and 0.5 mg/L AgNPs showed about 4 days earlier rooting formation and the plantlet growth such as plantlet height (5.60 cm), fresh weight (242.67 mg), dry weight (34,67 mg), number of roots/plantlet (6.67), root length (3.40 cm), SPAD (39.30 nmol/cm2) were higher than those in the control after 15 days of culture. Besides, the ethylene gas content in the culture bottle (0.06 ppm) in the 0.5 mg/L AgNPs treatment was lower than as compared to that in the control (0.15 ppm) after 15 days of culture. A shoot density (10 shoots) in 250 mL culture bottle with 40 mL of medium gave optimal growth than those in other treatments after 15 days of culture. Square plastic box culture system (length × width × height: 19 cm × 19 cm × 7 cm; 2.5 L in volume) containing 250 mL MS medium added to 0.5 mg/L AgNPs produced 100 vigorous plantlets; meanwhile, rectangular plastic box system (34 cm × 23 cm × 13 cm; 10 L in volume; 10 L in volume) produced 200 vigorous plantlets. Plantlets derived from 0.5 mg/L AgNPs treatment in the plastic box systems exhibited well acclimatization after 30 and 60 days of culture in the greenhouse.

In this study, a new method for shoot regeneration via protocorm-like bodies (PLBs) is described. Shoot proliferation using stem elongation under light-emitting diodes (LEDs), and enhanced growth of Anthurium andraeanum ‘Tropical’ plantlets on medium containing silver nanoparticles (AgNPs) was investigated. For shoot regeneration, the micropropagation efficiency via PLB formation was fourfold more efficient than directly from callus after 12 wk of culture. This was possible because each initial callus cluster could be cut into 20 explant slices (1 × 5 × 5 mm in size), each with an average of 42.67 PLBs which are capable of growing into plants. For shoot proliferation, single shoots with 2 cm in size derived from PLB culture were placed under different blue to red LED ratios. This study showed that higher shoot height (4.77 cm), fresh weight (327.33 mg), number of leaves per shoot (6.33), and the number of stem nodes per shoot (5.67 stem nodes) were obtained under 70R:30B as compared to those under other lighting conditions and fluorescent lamp after 8 wk of culture. Especially, the total shoot proliferation (10 shoots) via stem node culture was higher than those in the control. For enhanced plantlet growth, single shoot with a pair of leaves derived from stem elongation under 70R:30B cultured on 1/4 MS medium supplemented with 0.5 mg L−1 NAA and 1 g L−1 activated charcoal, 7 mg L−1 AgNPs, 30 g L−1 sucrose, and 8 g L−1 agar gave the highest growth than other treatments. Plantlets derived from 7 mg L−1 AgNP treatment transferred into greenhouse showed better growth as well as 4-wk earlier flowering than the control treatment.

Dendrobium officinate Kimura et Migo, a species of orchid for beautiful flowers, is used in traditional medicine in many Asian countries because there are many important pharmaceuticals (chrysotoxene, erianin, confusarin, polysaccharide, alkaloid ...) in anti-cancer, anti-aging, boosting immunity and vasodilation, etc. In recent years, more than 4,000 hectares of Dendrobium officinate Kimura et Migo artificial planting has been available in China and the price of dry product was around ¥ 80,000/kg. Currently, plantlet quality is an important factor influencing the acclimatization stage, growth, and development of plants in the greenhouse. In this study, the effect of a number of factors medium, plant regulator, ventilation, and substrate to improve plantlet quality as well as further growth and development in the greenhouse conditions were investigated. The results showed that SH medium was suitable for in vitro shoot growth in terms of monitoring parameters after 90 days of culture. In shoot multiplication stage, the shoots culture on SH medium supplemented with 2 mg/L BA, 30 g/L sucrose, 9 g/L agar, 1g /L activated charcoal (AC) gave the best results with 4.53 shoots/per shoot. The SH medium supplemented with 1.0 mg/L NAA, 30 g/L sucrose, 9 g/L agar, 1.0 g/L AC combined with ventilation conditions was suitable for rooting stage with plant height (5.73 cm), number of roots (4.77), root length (5.00 cm), fresh weight (3.36 g), dry weight (0,31 g), and total chlorophyll (SPAD) (45.76 nmol/cm2). Plantlets derived from culture ventilation conditions cultivated on the mixture of pine bark and fern fiber (50:50) was the highest survival rate (100%) and growth after 12 months in the greenhouse.

Artichoke (Cynara scolymus L.), a medicinal plant with high economic value, contains high levels of phenolic compounds; especially cynarine, which plays an important role in preventing cancer, cardiovascular disease, osteoporosis, diabetes and neurodegeneration, etc. Currently, Artichoke micropropagation has achieved some success; however, the rooting efficiency and plantlet quality are still limited. In this study, improving the quality of Artichoke plantlet related to the shoot quality and suitable substrates in in vitro rooting stage was studied on “Violetta” Artichoke (VA) and “Green Globe” Artichoke (GA). The results showed that shoots (1.5 cm) cultured on MS medium supplemented 0.5 mg/L KIN were most suitable to shoot multiplication of VA with the number of shoots/explant (3.67 shoots), number of shoots ≥ 2 cm (3 shoots); while, 1.0 mg/L BA was suitable to shoot multiplication of GA (5.33 shoots; 5.00 shoots; respectively) after 4 weeks of culture. Besides, the in vitro rooting was improved using 8 g/L commercial agar for VA; meanwwhile, 3 g/L gelrite for GA. In addition, the nylon bag culture system (120 mm × 250 mm) has potential in plantlet production (15 plants/bag) and can be applied for large scale micropropagation. In addition, VA and GA plantlets derived from in vitro culture gave the good acclimatization, growth and development after 8, 12 and 20 weeks cultivating at the green house conditions.

Artichoke (Cynara scolymus L.), a high economic value crop, was brought to Vietnam by the French in the late 19th century. The artichoke was mainly planted in Lam Dong, Lao Cai, Vinh Phuc provinces, etc. At present, the disease situation of Artichoke plants and the lack of disease-free seedlings result in insufficient source of Artichoke for producers. Artichoke plants are mainly vegetative propagation and pathogens easily transferred from mother to daughter plants. Therefore, low propagation rate and fungal infection are two main factors hindering the expansion and development of Artichoke cultivation (in Lam Dong). Therefore, studying and evaluating the situation of fungi and viruses as well as establishing the in vitro propagation procedures in order to produce high number of disease-free seedlings are urgent for the current Artichoke shortage. In this study, samples of purple and white Artichoke varieties, which suspected fungal manifestations, were collected to assessment of fungi and viruses in artichoke. In addition, in vitro propagation by cultivating apical meristem was applied to produce disease-free seedlings. The recorded results showed that, 19 strains of mold were identified on purple and white Artichoke belonged to nine genera including Mucor (M. sp., M. circinelloides, M. fragilis, M. irregularis, and M. racemosus), Alternaria (Alternaria sp., A. alterinata, A. gaisen, A. tenuissima, and A. tillandsiae), Fusarium (F. acuminatum and F. solani), Cylindrobasidium (Cylindrobasidium sp1 and Cylindrobasidium sp2), Actinomucor elegans, Curvalaria clavata, Plectosphaerella oligotrophica, Phoma herbarum, Rhizomucor variabillis; meanwhile, the Tomato mosaic virus (ToMV) was isolated only purple Artichoke. Shoot explants obtained from apical meristem culture were completely disease-free and used for micropropagation at the next stage.

One of the common problems in strawberry (Fragaria × ananassa) micropropagation is the vitrification phenomenon (succulent plantlets, brittle stems, yellow leaves, etc.) leading to the reduction of plantlets quality and low survival rate in the greenhouse. In this study, the effects of silver nanoparticles (AgNPs) on explant disinfection, in vitro growth (shoot multiplication, and root formation), runner formation as well as ethylene accumulation during micropropagation of strawberry were investigated. The results showed that leaf explants treated with 200 mg/L AgNPs solution for 20 min was more effective in explant disinfection and shoot regeneration than using 1 g/L HgCl2. In addition, AgNPs stimulated the growth of shoot and plantlet and as well shortened the duration of root formation (4 days) as compared to those in control without AgNPs during micropropagation. Besides, AgNPs reduced the ethylene gas accumulation in the culture’s vessels of shoots (0.66 ppm) and plants (0.06 ppm) compared to controls (1.77 ppm; 0.15 ppm; respectively). Moreover, AgNPs combination with culture period (5; 10 or 15 days) effect root formation stage and acclimatization in the greenhouse. The plantlets that cultured on MS medium supplemethed with 0.5 mg/L AgNPs during 10 days showed higher survival rate (93.33%) after 15 days as well as runner formation per plant (8.00 runners) after 60 days in greenhouse than those in control. AgNPs improved explant disinfection and in vitro growth. AgNPs improved runner formation in the greenhouse. AgNPs limited ethylene accumulation during micropropagation.

Conjugated linoleic acid (CLA) have been shown to exert numerous health benefits, including anti-carcinogenic, anti-atherogenic, anti-diabetic, antiobesity, cholesterol reducing, antioxidant, anti-microbial, immune system modulator and growth-stimulating properties. In human, CLA is produced from Linoleic acid (LA) by gut bacteria. In this study, nineteen Lactobacillus (Lac.) strains isolated from human feces were studied to determine their ability to metabolize LA. The bacteria were grown in the liquid form of anaerobic MRS medium supplemented with 0.5 mg/mL LA. The linoleate isomerase activity in bacteria grown on MRS medium was determined by Gas chromatograpy. The results indicated that 4 out of 19 strains, including strains Lac.02, Lac.05, Lac.14 and Lac.16 are capable of producing about 40-50 μg/mL CLA from LA. Among them, the highest ability to produce CLA from LA is Lac.02 strain. In the production of CLA from LA, enzymes involved in this metabolism in Lactobacillus act as catalysts of hydration/dehydration (CLA-HY), oxidation of hydroxy groups/reduction of oxo groups (CLA-DH), migration of carbon-carbon double bonds (CLA-DC), and saturation of carbon-carbon double bonds (CLA-ER). The cla-dh, cla-dc, cla-hy and cla-er genes that encode enzymes CLA-DH, CLA-DC, and CLA-ER had been found in all Lac.02, Lac.05, Lac.14 and Lac.16 strains. Gas chromatography traces indicated that these strains produced the same compounds, which was subsequently identified as cis-9, trans-11, and trans-10, cis-12 CLA. In the next study, we will optimize the conditions such as substrate concentrations, pH values, temperature and culture time of each strain to obtain the best rerults.

In this study, morphogenesis and anatomy of adventitious roots and hairy roots of Ngoc Linh ginseng (Panax vietnamensis Ha et Grushv.) were compared. Adventitious roots were derived from four different samples (leaf, petiole, root and callus) in vitro cultured on medium SH supplemented with 5 mg/L IBA. Hairy roots were derived from callus infected with Agrobacterium rhizogenes strain ATCC 15834. The results showed that there were significant differences in morphogenesis and anatomy, the pathway of secondary roots formation, culture medium between adventitous roots and hairy roots. The hairy roots strongly grew and branched on the free-plant growth regulator medium. The secondary root of the hairy root was formed in two pathways: (1) The secondary root formation began at the vesicles system of main root; (2) The secondary root formation was independent of the vesicles system of main root; it kept developing in length and connected to the vesicles system of main root. On the other hand, growing adventitous roots only grew on the environment with exogenous auxin supplementation; also their branching ability were low. The secondary root formation of the adventitous root was started at the vesicles of the main roots and there was only one secondary root that was formed at an location of adventitous root. The results that obtained in this study will be the reference to identify two types of root.

Somatic embryo is a developmental method for mass multiplication of valuable medicinal plants. In this study, leaf explants of Ngoc Linh ginseng were disinfected with nano silver at different concentrations and exposure times to eliminate infectious agents and induce embryogenic callus for the production of somatic embryos. The results show that the lowest contamination rate (20.00%) was observed when leaf explants were treated with 0.5 g/L nano silver for 15 minutes while the highest embryogenic callus induction rate (72.22%) and fresh weight (0.77 g) was determined at 0.2 g/L nano silver for 20 minutes. High frequency of somatic embryogenesis formation and germination were occurred on MS medium supplemented 1.0 mg/L 2,4-D; 0.5 mg/L NAA; 0.2 mg/L Kin and 1.6 mg/L nanosilver. After 8 weeks of culture, the number somatic embryos derived from nano silver treated-leaves was increased 2 times than non-treated explants. Addition of 1.0 mg/L NAA and 1.2 mg/L nano silver was showed the highest shoot and root length, root number, fresh and dry weight of plantlets. This research showed that pre-treatment and supplement of nano silver in culture medium is potentially useful for improving embryogenesis frequency, and plantlet formation of Ngoc Linh ginseng cultured in vitro.

In plant tissue culture, iron nanoparticles (FeNPs) was one of the first types of nano to be used in plants. Previous reports have identified the effect of FeNPs on many different plant species. In this study, FeNPs was used to replace Fe-EDTA in MS (Murashige, Skoog, 1962) medium to assess their effects on growth, chlorophyll (a, b and a+b) accumulation, antioxidant activity of ascorbate peroxidase (APX) and superoxide dismutase (SOD) enzymes, and acclimatization in greenhouse conditions in different culture systems (in vitro solid, in vitro hydroponic and microponic culture). The obtained results show that FeNPs added to MS medium was higher growth, chlorophyll (a, b and a+b) content, antioxidant activity of SOD and APX enzymes than Fe-EDTA in MS medium as control treatment. The effect of FeNPs are differences between culture systems. In vitro solid and microponic culture systems, the optimal concentration is 75 mM FeNPs and in vitro hydroponic culture system is 100 mM FeNPs. The optimal activity of the antioxidant enzyme SOD (35.04 U.mg−1 prot) obtained in the roots of cultured plants in microponic culture system; meanwhile, the optimal activity of the antioxidant enzyme APX (2.11 μmol.min−1.mg−1 prot) obtained in leaves cultivated in solid culture system. The plantlets derived from MS medium added FeNPs were transfered into greenhouse conditions, the microponic cultivated plants supplemented with FeNPs at a concentration of 100 mM gave the highest survival rate (94.67%). The results of this study showed that FeNPs can replace Fe-EDTA salt in MS medium, and iron deficiency in culture media will reduce chlorophyll content.

Polygonum multiflora Thunb. (Belongs to Polygonaceae family) is a medicinal plant of economic value and should be protected, according to the Red Book of Vietnam. Many studies have shown that P. multiflora Thunb. was effective for many diseases such as hair loss, premature gray hair, lower back pain, knee weakness, muscle weakness, hemiplegia, nervousness, dizziness, insomnia, etc. Propagation and preservation of this herbal species are significantly important because of increased demand. Adventitious root biomass culture has been successful on a number of plant species, and that it has potential for P. multiflorum breeding. In this study, the effect of explants, plant growth regulators and different culture systems on adventitious root formation was investigated. The adventitious roots were induced from the explants and the optimum culture medium were transferred to four different culture systems (3-liter triangular flask, shaking triangle, bioreactor self-made and Korean bioreactor) containing 5 g adventitious roots per 1 liter medium. The results showed that the leaf cultured on SH medium supplemented with 1.5 mg L-1 IBA, 30 g L-1 sucrose, 8.5 g L-1 agar and pH 5.8 gave the higher of adventitious root regeneration rate (100%), root number/explant (25.33 roots), fresh weight (131.67 mg) and dry weight 13.35 mg) compared to those cultured on other condition after 6 weeks of culture. The adventitious root multiplication in the Korea bioreactor system is more effective than other culture systems shown in the fresh biomass (17.04 g), dry biomass (1.56 g) and proliferation rate (3.40 fold) after 6 weeks of culture.

Jewel orchid (Anoectochilus setaceus Blume) is one of the important medicinal plants used for many common diseases treatment such as hypertension, diabetes, and heart, liver and lung diseases, as well as improving the health in general. Polyploid induction using colchicine and oryzalin has been widely performed in various types of crops and could be considered a valuable tool for plant breeding. In the present study, in vitro young shoots of A. setaceus Blume (1 cm in height) were treated with different concentrations of colchicine (0, 1, 2, 4, 6, 8, and 10 µM) and oryzalin (0, 10, 20, 40, 60, 80, and 100 µM) at different durations (0, 12, 24, 36, and 48 h). The results showed that shoots with length of treatment from 24 to 48 h and the concentrations from 2 to 10 µM of colchicine and from 40 to 100 µM of oryzalin appeared morphological differences (10.00% - 16.00%) but the tendency to return to normal of these shoots after several times of sub-culture was observed. Stomatal length had a close correlation with the level of ploidy. Diploid plantlets (2n = 2x) had the average stomatal length of 33.50 µm when observed under an optical microscope at 100x magnification and corresponding to the peak at 70 FL in flow cytometric DNA histogram. In all identified polyploid plantlets, the stomatal lengths were greater than 40.12 µm. Moreover, flow cytometric analysis indicated that plantlets with stomatal lengths ranged from 40.12 to 50.00 µm were diploid-tetraploid mosaicisms represented by two separate peaks at 70 FL and 90 FL. Finally, samples treated with 4, 6, and 8 µM colchicine with treatment time of 48 h, and 60 µM oryzalin with treatment time of 24 h that had stomatal lengths ranged from 52.03 to 71.25 µm were determined to be tetraploid (2n = 4x) represented by a peak at 120 FL position.

Smoking is widely known to has a major contributor to public health issues both in worldwide and Vietnam. At the same time, Vietnam have a large number of smokers and the market is filled with diverse brand of tobacco products. In this study, we sampled 6 types of cigarette: ThangLong, Vina, Craven, Demi, Maxx and Bastos from local stores and conducted toxicological test on zebrafish larvae. Our results show that there are varied in toxicological properties of total particle matter collected from different cigarette brands in lethal and morphology effects on zebrafish embryos. LC50 of 6 brands after 96 hours of exposure were: ThangLong = 48.7 mg/L, Vina = 45.96 mg/L, Craven = 80.52 mg/L, Demi = 30.91 mg/L, Maxx = 83.54 mg/L and Bastos = 74.92 mg/L. They are lower than 100 mg/L, which put them under Category 2 and 3 in the GHS classification criteria for acute toxicity.

New ornamental varieties with higher quality can be created via artificial polyploid induction. In the present study, the first polyploid induction of Paphiopedilum villosum was described. In vitro young shoots of Paphiopedilum villosum were produced shoots to be used as material for inducing autopolyploidization. Initial shoots were extended in the dark to form three distinct stem nodes and then adventitious shoots were induced from nodal explants from the elongated shoots. Therein, the effects of cytokinins (BA, KIN, and TDZ) and node position on shoot induction were investigated. The shoots (1.5 cm high) derived from the first nodes in 0.5 mg/L TDZ supplementation medium were incubated in colchicine solution at different concentrations and durations and then transferred to rooting medium. Polyploid induction rate reached 19.88% in the treatment of 50 μM colchicine and 6 days. Among obtained polyploidy plantlets, tetraploids (88.24%) and mixoploids were identified by flow cytometric analysis and chromosome counts of root tip tissue squashes. The combination of shoot regeneration from stem nodes and colchicine treatment gives an effective method for the production of polyploid plantlets for further breeding purposes of P. villosum as well as other endangered orchids.

Paphiopedilum spp. is one of the most commercially popular orchids because of its variety of shapes, sizes, and colors. However, it is at risk for extinction because of its exploitation. Regeneration of orchid plants using internode segments is extremely difficult. In this study, young P. callosum plants (1.5 cm) were exposed to eight dark–light cycles (14 days of dark and 1 day of light) for stem elongation to increase the number of nodes to obtain internode tissues. After 75 days of culture, the highest callogenesis (31.25%) was achieved when internode tissue was cultured on liquid Schenk and Hildebrandt (SH) medium containing 30 g·L−1 sucrose, 1.0 mg·L−1 Thidiazuron (TDZ), 1.0 mg·L−1 2,4-Dichlorophenoxyacetic acid (2,4-D), and cotton wool as the support matrix. The optimal media for induction of protocorm-like bodies (PLBs) were the same compositions as previously mentioned and were supplemented with 9 g·L−1 Bacto agar as the gelling agent. PLB clumps (5–6 PLBs/clump) produced the best shoots on medium containing 0.5 mg·L−1 α-Naphthaleneacetic acid (NAA) and 0.3 mg·L−1 TDZ. Among the organic substances tested, 200 g·L−1 potato homogenate (PH) added to Hyponex N016 medium supplemented with 1.0 mg·L−1 NAA, 30 g·L−1 sucrose, 170 mg·L−1 NaH2PO4, 1.0 g·L−1 peptone, and 9 g·L−1 Bacto agar resulted in the best rooting. The rooted plantlets with four to five leaves were acclimatized and had a 100% survival rate. The method presented in this research provides a strategy for the development of highly effective propagation of Paphiopedilum species using ex vitro explants for both conservation and horticultural purposes.

Aedes aegypti and Ae. albopictus are key vectors in the spread of arboviruses such as dengue, chikungunya, yellow fever, and Zika. Triatoma rubrofasciata is an “assassin bug” whose populations and association with humans have dramatically increased and may represent a serious health concern. Control of insect vectors is a logical course of action to prevent the spread of these insect-borne infections. This work presents the leaf essential oil composition, mosquito larvicidal activities, and insect-repellent activity of Severinia monophylla. The essential oil of S. monophylla from Vietnam was obtained by hydrodistillation and analyzed by gas chromatography and mass spectrometry. The major components were sabinene, β-caryophyllene, bicyclogermacrene, germacrene D, (E)-nerolidol, globulol, and linalool. The leaf essential oil showed remarkable larvicidal activity against Ae. aegypti with LC50 (48 h) of 7.1 μg/mL and Ae. albopictus with LC50 (48 h) of 36 μg/mL. The essential oil also showed repellent activity on T. rubrofasciata at a concentration of 0.5%.

Saponin compounds released by Panax vietnamensis into the rhizosphere play critical roles in drug discovery. This study investigated the growth and saponin accumulation of P. vietnamensis adventitious root. Results showed the root growth and productivity of three-saponins (MR2, Rb1, and Rg1) were increased highest on the modified MS medium containing 7 mg/L IBA and 0.5 mg/L BA at 56 days. The root culture divided into three phases: (1) Growth phase 14–56 culture-days; (2) Stationary phase 56–70 days; and (3) Decline phase after 70 days. Saponin accumulation was significantly increased in the treatments of three plant-hormone-elicitors (JA, ABA, and SA), and two cell-wall elicitors (YE and CHN), but five elicitors inhibited formation lateral roots. Although contents of Rg1 (0.32%), Rb1 (0.85%), and MR2 (2.83%) were highest in JA treatment at 0.48 mM, 0.24 mM, and 0.96 mM JA respectively, maximum biomass as well as saponins productivity was observed in 150 mg/L YE. In addition, combination of YE and SA showed effective lower than the solitary YE treatment. The results suggest that adventitious root biomass of P. vietnamensis developed effectively in the modified MS medium after 56 days, and the culture could be scale-up in bioreactor 20 L.

Mosquito-borne diseases are a consistent problem in Vietnam. Additionally, freshwater snail species are agricultural pests and are known to be intermediate hosts for several parasitic worms. There is a need for new and complementary botanical pesticidal agents for controlling these pests and essential oils have shown promise. In this work, essential oils from 2 species of Callicarpa ( C. rubella and C. sinuata) and 4 species of Premna ( P. chevalieri, P. corymbosa, P. maclurei, and P. tomentosa) were screened for mosquito larvicidal activity against Aedes albopictus and Culex quinquefasciatus and for molluscicidal activity against 3 freshwater snail species, Gyraulus convexiusculus, Pomacea canaliculata, and Tarebia granifera. Callicarpa rubella essential oil showed exceptional larvicidal activity against Cx. quinquefasciatus with 24-h LC50 of 9.8 μg/mL. In addition to C. rubella, the essential oils of P. chevalieri and P. tomentosa showed notable molluscicidal activities against P. canaliculata with LC90 values ≤ 20 μg/mL. These Callicarpa and Premna essential oils were all rich in sesquiterpenes and should be considered for continued investigation as botanical pesticidal agents.

In this research, nanosilver with different concentrations and treatment time was used to sterilize infection agents and induce initial explants which were used as materials for cell suspension culture of Limonium sinuatum. The result showed that leaf explants sterilized with 0.2 g/L nanosilver for 20 minutes had highest effect (live rate 73.33%) comparing to HgCl2and Ca(ClO)2(56.66% and 64.44%, respectively). In addition, the leaf explants which were treated with nanosilver and cultured in ½ MS medium supplemented with 20 g/L sucrose, 1 mg/L picloram and 2.5 g/L gelrite also induced calli (friable calli, milk white color, embryogenic callus structure). Moreover, cell suspension formation process from these calli was also observed highest on the 20thday (49,088 cells/mL) in liquid shaking culture condition comparing to control treatment (19,361 cells/mL) when they were cultured on similar medium combined with 1.2 mg/Lnanosilver. These cells had the best growth, development and regeneration from the 16thday to the 20thday. The ability of shoot and callus regeneration was highest (67.77%) in ½ MS medium which was supplemented with 20 g/L sucrose, 1 mg/L zeatin, 2.5 g/L gelrite and 1.6 mg/L nanosilver compared with control treatment having no nanosilver (40.00%). This research showed that in micropropagation of Limonium sinuatum, nanosilver was proved to be an effective agent for sterilization, explant induction, cell suspension origination, and callus and shoot regeneration. Beside that, nanosilver had negative impact on the development of explants when it was used with high concentration for extended period.

Paphiopedilum villosum is a beautiful orchid species and has high value in trade; however, this is one of the most difficult to propagate orchids. So far, there has been very little publication on micropropagation. In this study, the effects of plant growth regulators on shoot regeneration from stem node culture of elongated P. villosum shoots in the darkness were investigated. Shoots (1.5 cm) were elongated and produced individual stem nodes under darkness condition for 3 months. Stem nodes were cultured on SH medium and supplemented with individually BA, KIN or TDZ to investigate shoot regeneration. The shoot multiplication rate was also recorded in this study. The highest stem node was observed in the dark with 5.25 cm in the height and the number of stem nodes were 3 stem nodes/shoot. The isolated stem node was cultured on SH medium supplemented with 30 g/L sucrose, 8 g/L agar, 1 g/L charcoal and different concentrations of BA, KIN, TDZ. The results observed after 3 months showed that the best shoot regeneration rate (85%) and highest shoot multiplication coefficient (6.6 shoots/stem node) was obtained when shoots derived from stem node were cultured on SH medium supplemented with 0.5 mg/L TDZ, 30 g/L sucrose, 8 g/L agar and 1 g/L charcoal. Those shoots obtained in the above treatments were subcultured on MS medium supplemented with 0.3 mg/L NAA for rooting and gave the highest number of roots (6.6 roots/shoot) after 1 month; and these plantlets were acclimatized in Taiwan sphagnum moss and transferred into greenhouse with the best survival rate (100%) after 3 months.

In recent years, the Agrobacterium-mediated genetic transformation system has become the most useful method widely used for the introduction of foreign genes into plant cells followed by regeneration of genetically improved plants. Panax vietnamensis Ha et Grushv. is a highly valued medicinal plant native to Vietnam with limited area of distribution. This report illustrates the possibilities of biotechnology for genetic transformation aimed at establishing an effective production of secondary metabolites in P. vietnamensis. In the present investigation, 0.5 cm2 leaf blades, 1 cm long leaf petioles and 0.5 cm3 callus clusters were used for the hairy root induction. Results indicated that hairy roots were induced on P. vietnamensis callus clusters co-cultivated with Agrobacterium rhizogenes strain ATCC15834 at OD600 of 0.5 with an infection time of 20 min and a supplementation of 100 mM acetosyringone. PCR amplification of the DNA isolated from the resulting hairy roots was used to confirm the presence of rol genes. Compared to in vitro rhizome cultures, hairy root cultures appear to be potential for continuous production of valuable secondary metabolites with similar saponin profiles. The protocol described in this study is simple and rapid and therefore, can be used for large-scale experiments for the rapid production of valuable compounds.

Micropropagation has proven to be an effective method for large-scale plant production in a short time and a useful tool for plant breeding. Microbial contamination is one of the most difficult micropropagation challenges, resulting in reduced plant quality and loss of valuable stocks. Therefore, sterilization of culture media is a critical step in plant micropropagation. However, sterilized media might reduce the activity of plant growth regulators and nutritional components of culture media. The sterilization effects of silver nanoparticles (AgNP) on the growth of explants and culture media were examined. The treatment with 250 ppm AgNP for 15 to 20 min of 4-wk-old ex vitro leaves proved optimal for controlling the contamination. Furthermore, the Murashige and Skoog medium containing 4 ppm AgNP resulted in 100% medium disinfection (no contamination) after 4 wk of culture. The plantlets obtained from non-sterilized MS medium (NoM) containing 4 ppm AgNP and 4 g L−1 agar gave similar results as the control medium with 8 g L−1 agar and the absence of AgNP. Large scale culture systems using NoM in large plastic containers of two different sizes (NoM1 and NoM2) could produce quality plantlets. Chrysanthemum plantlets in the NoM1 system showed higher antioxidant enzyme activities of ascorbate peroxidase and superoxide dismutase than plantlets in the autoclaved medium. Furthermore, the plantlets from NoM were better acclimatized under greenhouse conditions than those from the autoclaved medium (AuM) system. The developmental stages (flower buds and blooming time) of NoM1 and NoM2 plantlets, were 1 wk earlier than those from the AuM system. The successful use of AgNP as a sterilizer and as a component of culture media would reduce the cost of micropropagation and improve plants' quality.

The purpose of this work is to evaluate the performance of novel hydrfo-pneumatic suspension system (HPSs) in comparison with traditional hydro-pneumatic fsuspension system (HPSs) of a heavy truck in the direction of improving vehicle ride comfort. Firstly, the nonlinear dynamic models of the traditional and novel HPS systems are set up to determine the vertical forces. And then, the vertical forces are connected with a 3-D nonlinear dynamic model of heavy truck with 10 degrees of freedom under random excitation of road surface. The root mean square (RMS) acceleration responses of the vertical cab, pitch and roll angles of the cab (awzcb, awfcb and awtcb) based on the International Standard ISO 2631-1: 1997 are chosen as objective functions. The study results show that the awzcb, awfcb and awtcb values with novel HPSs reduce by 28.27%, 28.32% and 6.89% in comparison with traditional HPSs when vehicle moves on ISO class D road surface at vehicle speed of 50 km/h and full load. Finally, the ride performance of novel HPSs is verified and compared and evaluated with traditional HPSs under different operating conditions and the evaluation results are also indicated that the ride performance of a novel HPSs is better than the traditional HPSs under survey conditions.

Lactobacillus sp. in the digestive tract are capable of producing H2O2 to inhibit the growth of harmful bacteria and balance the gut microflora. In this study, we have isolated 115 strains of Lactobacillus spp. from stool samples of healthy people in Ha Noi. Of the 50 tested Lactobacillus strains, 9 strains were capable of producing H2O2, of which the Lac.VFE-14 strain produced highly H2O2 with a concentration of 2.183 mM, followed by Lac.VFE-08 strains (2.081 mM) and Lac.VFE-04 (2.067 mM). All three strains grew well in MRS medium supplemented with bile salts or adjusted to low pH value. With 0.3% of bile salt, the survival rates of these 3 strains were 99%, 95% and 97%, respectively. At pH 3.0, after 3 hours of cultivation, the survival rates of the three strains were 98.54%, 94.15% and 95.27%, respectively. In addition, each of the cell-free culture supernatants of these three strains that inhibit the growth of S. aureus ATCC-23235. The inhibition zone diameters of the three strains were 19.0±1.0 mm, 14.0±1.0 mm and 11.7±1.3 mm, respectively. The results of 16S rRNA gene analyses showed that Lac.VFE-14, Lac.VFE-08 and Lac.VFE-04 had high similarity scores with L. plantarum ZZU 23 (100%), L. rhamnosus JCM 1136 (99%) and L. plantarum S7 (98.65%), respectively. This study indicates that all three strains have the potential to be used as probiotics in the future.

A microponic culture system, combining micro-propagation and hydroponics, could reduce the drawbacks of micro-propagation system such as being prone to contamination, being resource-intensive and require large areas, etc. In this study, chrysanthemum shoots (3 cm in length) were cultured in a microponic system and micro-propagation system. The growth of shoots cultured on half-strength sugar-free liquid MS medium supplemented with 7.5 ppm silver nanoparticles under 70% red LED combined with 30% blue LED were the highest among tested concentrations. Results of qualitative and quantitative tests of microbial contents in the microponic culture by 4 testing methods indicated that at concentration of 7.5 ppm silver nanoparticles effectively reduces microbial counts of 8 tested bacteria (Corynebacterium sp., Enterobacter sp., Arthrobacter sp., Agrobacterium sp., Xanthomonas sp., Pseudomonas sp., Bacillus sp. and Micrococcus sp.) and 3 fungi (Aspergillus sp., Fusarium sp. and Alterneria sp.). After 12 weeks at the nursery stage, the chrysanthemum plants derived from microponics began to bear flower-buds. Chrysanthemums produced by the microponic system started flowering after 15 weeks, which was 1 week earlier than those produced by in vitro micropropagation. Taken together, a microponic system was developed and tested successfully. The shoots derived from microponic culture could flower normally at 1-week earlier than the micropropagation-derived ones. The approach was proved to be both cost and time saving.

Mosquitoes are the deadliest animals on earth and are the vectors of several neglected tropical diseases. Recently, essential oils have emerged as potential renewable, cost-effective, and environmentally benign alternatives to synthetic pesticides for control of mosquitoes. In this work, thirteen species of Piper were collected from different areas of central Vietnam. The essential oils were obtained by hydrodistillation and analyzed by gas chromatography&ndash, mass spectrometry. The essential oils were screened for mosquito larvicidal activity against Aedes aegypti. Four of the Piper essential oils showed outstanding larvicidal activity against Ae. aegypti, namely P. caninum, P. longum, P. montium, and P. mutabile, with LC50 and LC90 values less than 10 &micro, g/mL. Multivariate analysis has correlated concentrations of &beta, caryophyllene, &beta, bisabolene, &alpha, pinene, and &beta, pinene with mosquito larvicidal activity.

No report on plant regeneration via somatic embryogenesis of P. vietnamensis has been previously published. In the present study, somatic embryogenesis via callus formation from cultures of leaf transverse thin cell layers (tTCLs) of Vietnamese ginseng (Panax vietnamensis Ha et Grushv.) was investigated. α-naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BA) and thidiazuron (TDZ) were added separately and in combination into the culture media. Explant necrosis or low callogenesis rates were observed when 1-mm wide leaf tTCLs were cultured on media with TDZ, BA, 2,4-D or NAA. On the other hand, calli were successfully induced from the tTCL explants cultured on medium supplemented with either 2,4-D and BA or 2,4-D and TDZ. Callogenesis was observed under both light and dark conditions. The highest callogenesis rate (100%) was obtained on Murashige and Skoog (MS) basal medium supplemented with 1.0 mg l-1 2,4-D in combination with 0.1 mg l-1 TDZ in darkness after eight weeks of culture. White calli were cut into small pieces (1.0 x 1.0 cm dimension) and placed on MS media containing 1.0 mg l-1 2,4-D, 0.5 mg l-1 NAA and TDZ at various concentrations (0.01; 0.1; 0.2; and 0.5 mg l-1), and the best callus proliferation was recorded on medium containing 1.0 mg l-1 2,4-D and 0.2 mg l-1 TDZ. Somatic embryogenesis, with a success rate of 53.3% and 35 embryos per explant, was achieved when calli were subcultured onto MS medium supplemented with 1.0 mg l-1 2,4-D, 0.5 mg l-1 NAA and 0.2 mg l-1 TDZ.