Vol. 6 No. 4 (2023): Vietnam Journal of Agricultural Sciences

Mung bean (Vigna radiata L. Wilczek) is grown mainly under rainfed conditions, facing water deficits in different growth stages. This study was conducted to evaluate the responses of a local cultivar, Dau tam Thanh Hoa, and three introduced mung bean cultivars (DX14, Mongo Labo, and TV06425) to water stress at the different growth stages. The experiment was carried out in a greenhouse following a completely randomized arrangement with two replications. Drought was induced by withholding water at either the vegetative or flowering growth stages for 20 consecutive days. The control consisted of well-watered plants. After 8, 12, 15, and 20 days of drought, plant available water, growth characteristics, and the weights of fresh stems and roots were measured. After 20 days of drought, plants were watered to assess their recovery after 7 days and the growth characteristics, weights of fresh stems and roots, and yield components at the harvest stage were evaluated. The results showed that drought affected the growth, resilience, and yield-related factors more severely at the vegetative stage than at the flowering stage. The longer drought was imposed, the greater decline in plant growth was observed. Despite the recovery, fresh root mass and root length were still 40-50% and 10-30% worse than the control, respectively. Based on the growth responses and individual yields, Dau tam Thanh Hoa and DX14 were more tolerant to water deficit and can be used as materials for improving the drought tolerance of mung bean.

Toxocara canis and T. cati are common roundworms parasitizing dogs and cats, respectively. However, a recent study detected T. malaysiensis, but not T. cati, in cats from some parts of Ha Noi and Nam Dinh Provinces raising the question of whether T. cati is present in cats in Vietnam. This study was conducted to determine the composition of Toxocara species in dogs and cats in Vietnam. One hundred and twenty-seven Toxocara adult worms were collected from dogs and cats and were analyzed by PCR-RFLP assay and DNA sequencing of a partial section of the cox1 gene. As a result, all samples amplified by PCR showed bands about 430 bp in length. PCR products digested by MseI from isolates from cats and dogs showed four and two restriction patterns, respectively. The six different patterns were chosen to sequence. Based on the restriction patterns and sequencing results, two Toxocara species were identified in the cats, namely T. cati (110/111 isolates) and T. malaysiensis (1/111 isolates) collected from Ha Noi and Hai Duong, respectively; and T. canis was identified in the dogs (16/16 isolates). In addition, the present study indicated intra-specific sequence variations of Toxocara spp. in dogs and cats. In conclusion, the study confirmed the presence of both T. cati and T. malaysiensis in cats, and T. canis in dogs in Vietnam, and suggests further large-scale investigations to fully understand the distribution and genetic variations of Toxocara spp. in cats and dogs in Vietnam.

Combined systems for wastewater treatment and resource recovery have been developed in many countries. However, systems for energy generation are still underdeveloped. This research was conducted to evaluate the possibility of electric potential generation from wastewater using a microbial fuel cell system (MFC). The simple two-chamber apparatus (2 liters) was fed with wastewater collected from dormitory discharge. Three batch experiments were carried out with 2 liters of wastewater with an influent concentration of 518 mg L-1 BOD5 and 750 mg L-1 COD. The results showed that the microbial fuel cell system generated a potential from 0.29 to 0.45 V for 7 days in the presence of 1.0-1.5% (v/v) Bacillus subtilis while this potential was not obtained in the case when microbes were not added. The highest removal efficiencies of BOD5 and COD reached 56% and 63%, respectively. It was found that the potential dropped to almost zero in all of the treatments while the ratio of BOD:COD was 0.83 and the concentration of BOD was around 230 mg L-1, indicating that other governing factors may have an impact on potential electricity generation. Therefore, further studies on the effects of the operating conditions and equipment should be comprehensively studied.

Dredging plays a crucial role in port management, but disposing dredged material in the ocean raises environmental concerns. In recent years, this practice has become more prevalent in Vietnam. This study examined the dispersion of total suspended solids (TSS) in seawater from the submersion of dredged material in Vung Ang Port, northern Vietnam, to evaluate the environmental impact. The study utilized MIKE modeling to simulate the dispersion of TSS during the 16 weeks following the submersion of dredged material into the sea. The model was validated with observed data and adjusted to accurately reproduce wave, water flow, and water level fields. The simulation showed that the propagation of TSS had a significant impact within a radius of 16-17km from the submersion location, with the most severe impact occurring within a radius of 2-3km. The TSS concentration is expected to exceed allowable limits, peaking after 4-5 weeks. Seawater occupation will reach maximums of 49.05ha and 140.66ha for depth increases above 0.5m and 0.1m. The submersion will negatively impact the environment. It is essential to regularly monitor TSS in affected areas during and after dredging to evaluate long-term effects and mitigation effectiveness. The significance of conducting additional research on the matter and the crucial insights offered by this study to pertinent management agencies for their decision-making processes are emphasized in the article. The study offers crucial insights for pertinent management agencies.

FtsZ proteins have been well-characterized to play a crucial role in cell division. Unfortunately, data are scarce on FtsZ proteins in the Lactococcus and Bacillus genera. The objective of this study was to analyze the features of FtsZ proteins in the Bacillus and Lactococcus genus groups. By exploring the available genomes, we identified and characterized FtsZ proteins in 19 Bacillus and 22 Lactococcus species. The sizes and weights of the FtsZ proteins ranged from 376 to 410 aa residues and 39.53 to 44.15 kDa in the Bacillus genus, respectively, and from 387 to 430 aa residues and  41.14 to 45.11 kDa in the Lactococcus genus, respectively. All the FtsZ proteins in the Bacillus and Lactococcus species were acidic and globular, and localized in the cytoplasm. Next, 3D modeling and multiple alignments were performed. We realized that the FtsZ proteins in the Bacillus and Lactococcus species exhibited five specific regions. Taken together, our study could provide a general background for further functional characterization of the FtsZ proteins in Bacillus and Lactococcus species.

Lentinula edodes (Berk.) Pegler, commonly known as shiitake mushroom, is one of the most popular edible mushrooms with valuable medicinal properties. Despite its global popularity, the cultivation of shiitake in Vietnam has been limited due to a lack of research on this macrofungus. This study aimed to optimize the culture conditions for the mycelial growth and fruiting body development of two shiitake strains, J1 and J2. The culture conditions were optimized by one-factor-at-a-time method. A temperature of 25°C was found to be optimal for the growth of both strains, while glucose was identified as the most effective carbon source. Yeast extract and ammonium chloride (NH4Cl) were found to be the optimal nitrogen sources for favorable mycelial growth of strains J1 and J2, respectively. The most suitable spawning material for upscaling the mycelium was a mixture of 74% grain rice, 25% sawdust, and 1% CaCO3. Additionally, the cultivation of strain J2 on a mixture of 69% corncobs, 20% sawdust, 10% wheat bran, and 1% CaCO3 led to a higher biological yield (36.5%) than that of strain J1 (23.5%). These findings provide useful information for improving the cultivation technology of shiitake and expanding its cultivation in Vietnam.

This study examined the phytochemical composition and algicidal effectiveness of Ludwigia octovalvis. The powder samples were extracted by ultrasound-assisted extraction with polar solvents (water-diluted ethanol, acetone, methanol, and water). The preliminary phytochemical analyses used standard procedures following Sofowora and Harborne. Total phenolic contents in extracts were determined by the Folin-Ciocalteu method using a calibration curve of gallic acid. The results showed that this plant contains polyphenols, flavonoids, anthraquinones, glycosides, and saponins. The best conditions for the extraction of polyphenol compounds with a total polyphenol content of 149.22 ± 0.96 mg GAE g-1 were acetone/water 70:30 (v/v) and a solvent-to-material ratio of 20 mL g-1. The inhibitory effect of the extracts against M. aeruginosa growth increased from 40.71 to 81.56% on day 7 when exposed to concentrations of the extract from 50-200 μg mL-1 according to the cell counting method. The L. octovalvis extract was identified as an effective inhibitor of the growth of M. aeruginosa.

The association among financial development, trade openness, natural resources rent, government expenditure, and economic growth has been investigated by scholars, but the results have been controversial. This study attempts to examine the relationship among financial development, trade openness, natural resources rent, government expenditure, and economic growth in three Northeast Asian countries, namely China, Japan, and the Republic of Korea, between 1981 and 2020 using the fixed effect and random effect models. The results of the feasible generalized least squares model stated that economic growth of these countries can be fostered by financial development and trade openness.  However, surprisingly, natural resources rent had a negative effect on the economic growth of the three countries in the region, while the relationship between government expenditure and economic growth was not statistically significant. Finally, policies are recommended to accelerate economic growth and achieve sustainable development for the region. First, financial development should be encouraged by improving domestic credit to the private sector. Second, trade openness should be facilitated to exploit competitive advantages in export-led growth, and science and technology. Finally, the countries should implement sustainable growth models to their reduce dependence on natural resources and achieve sustainable development for the region.

Chuong My is a suburban district of Hanoi with a rapid development of pig farming, accompanied by the problem of environmental pollution. For the sustainable development of livestock production, besides improving production efficiency, it is necessary to reduce environmental pollution. This study measured production efficiency considering environmental factors (environmental efficiency) to assess the sustainability of pig farms in the district. This study used the data envelopment analysis (DEA) model with undesirable output (COD emissions) to measure environmental efficiency in pig production. The research results showed that the average production inefficiency score was 1.07, while the average environmental inefficiency score was 1.19. This shows that if environmental factors are not considered, the measurements of production efficiency are biased. Using Tobit regression, the study showed that the factors that increased environmental efficiency were the installation of biogas digesters and the pollutant removal efficiency of manure treatment facilities. Meanwhile, increases in the volume of wastewater discharging into the treatment plants reduced environmental efficiency. These findings confirm the importance of biogas plants in manure treatment in Vietnam. To improve environmental efficiency, it is necessary to enhance the efficiency of treatment facilities and apply water-saving technologies in livestock production.

This study aimed to analyze the quality culture factors affecting the work motivation of lecturers at the Vietnam National University of Agriculture (VNUA). A quantitative research study was conducted with 197 samples through direct and indirect interviews. After collecting and processing data, a regression analysis was conducted to assess the impact of the quality culture factors on the work motivation of lecturers. The results showed that there are three groups of quality culture factors (human resource management and mission, training and evaluation of education programs, and quality assurance system) that have a positive impact, of which human resource management and mission have the greatest influence on the work motivation of lecturers. Based on the findings, recommendations on these quality culture factors were made to enhance the work motivation of lecturers at VNUA.