Vol. 3 No. 1 (2020): Vietnam Journal of Agricultural Sciences

Tomato is one of the most important vegetables cultivated in Vietnam. Besides its regular consumption as a vegetable, a new demand for using tomato as a decorative plant on special occasions was identified in recent years. This study aimed to characterize new tomato accessions on their desirable morphological traits to select potential materials for further breeding programs of ornamental tomato varieties in Vietnam. Twenty-four heirloom tomato genotypes were evaluated on 19 morphological traits. Based on the describing system for tomato developed by the International Plant Genetic Resources Institute (IPGRI, 1996), significant variation was assessed in both qualitative and quantitative traits related to fruit morphology. The results of principle component analysis indicated that three main principle components explained over 60% of the total phenotypic variation. The five traits of fruit size, fruit shoulder shape, fruit cross-sectional shape, number of locules, and shape of the pistil scar were recommended as important traits for clustering tomato genotypes in this study. In addition, the 24 genotypes were classified at the coefficient of 0.39 into six different clusters. Finally, six interesting accessions, AU66, AU67, AU68, AU73, AU79, and AU83 (with strange fruit colors and shapes), were selected as potential materials for further breeding programs of ornamental tomato in Vietnam.

The study was conducted from October 2016 to December 2017 at the Experimental Farm, Faculty of Animal Science, Vietnam National University of Agriculture, with the aim to evaluate the interaction between farming model types and reproductive performance of Ho and Dong Tao chickens. The two farming model types used in this research were (1) the traditional type – backyard and (2) the ameliorate type – battery cage. Data were collected from 61 Ho hens and 61 Dong Tao hens continuously during 52 laying weeks. The total number of eggs laid by hens raised in battery cages averaged 88.47 eggs (for Ho hens) and 94.91 eggs (for Dong Tao hens), 35-38% higher than the number of eggs laid by hens raised in a traditional model. The FCR index per 10 eggs laid in battery cages was significantly lower than that in the back-yard model (P< 0.001). In both the Ho and Dong Tao breeds, the rate between the number of embryonated eggs by number of incubated eggs recorded in the ameliorate model was higher than that recorded in the traditional model (P< 0.01 for Ho chickens, P< 0.001 for Dong Tao). The weight of eggs produced by hens raised in battery cages was higher than eggs laid by free-range hens for both Ho and Dong Tao chickens (P< 0.01). As such, the reproductive performances and egg quality of both Ho and Dong Tao breeds were apparently improved when chickens were raised in battery cages.

Staphylococcus aureus is a major problem in both the clinical setting and within the community. S. aureus can quickly develop resistance to a wide range of antibiotics through a number of different mechanisms, of which, using transporters located in the cell membrane to pump antibiotics out of the cell is the most serious concern. In staphylococcal species, QacA, one such important transporter, is encoded by qacA. QacA is 55kD in size and has 14 transmembrane segments (TMS) (TMS 1-TMS 14). This research describes the mutation process of the amino acid residues in TMS 11 of QacA using site-direct PCR. In this research, 15 primers were successfully designed for site-directed mutagenesis PCR. The site-mutagenesis PCR was successfully conducted to create 15 qacA mutants. These mutants will be used in further functional research of QacA.

The effects of frozen storage of goat’s milk on the physicochemical, physical properties, and sensory attributes of goat’s milk yoghurts were evaluated. Four yoghurts were made from goat’s milk stored at 4℃ overnight, and at -6, -20, or -35℃ for 1 month. Goat’s milk yoghurts were stored at 6℃ for 21 days. Protein and lipid contents in all the yoghurts were insignificantly different, however, the total solids content, including the added sugar in the yoghurts made from frozen goat’s milk, significantly increased in comparison with that in the yoghurt made from chilling goat’s milk. The water holding capacity (WHC) and viscosity for all the yoghurts at any period of cold storage were statistically different. No significant differences in pH or titratable acidity for all the yoghurts were observed after 1 day of cold storage; however, these physicochemical properties for the yoghurts after 7 days of storage were significantly different. All the yoghurts after 21 days of storage received similar scores for appearance and texture, but significantly different scores for color, odor, flavor, and overall acceptability. 

The C2H2 zinc finger protein ZAT12 has been classified as a plant core abiotic stress response gene in the early  response to multiple stresses. ZAT12 links the iron deficiency and oxidative stress responses through the direct interaction with/and negative regulation of a central regulator - FIT. For further research on the regulation of the ZAT12 protein in planta, a huge quantity of ZAT12 proteins is required to inject into mice for the generation of ZAT12 antiserum. In this study, the gene encoding the ZAT12 protein from Arabidopsis thaliana was cloned into the expression vector - pETBlue-2 and then overexpressed in E. coli T7. A high expression level was indicated by SDS-PAGE. Immunoblot demonstrated successful expression using a bacterial expression system.

In this study, with the aim of determining and assessing the influence of several culture conditions on the ligninolytic enzyme (LiP, MnP, and Lac) activity of bacteria, five lignin-degrading bacteria strains were isolated from two different soil samples and cultured on minimum salt medium agar containing alkaline lignin (MSML agar). Among the five isolated strains, DL1 and X3 expressed strong and stable ligninase enzyme activity at various temperature levels (30°C, 37°C, 50°C, and 60°C) and were selected for further study. Notably, at 60°C, the ligninase activity of both strains lasted until the seventh day before decreasing. The effects of the culture medium conditions, namely, carbohydrate sources, nitrogen sources, and pH, on the ligninolytic system illustrated that both X3 and DL1 were able to generate good enzymatic activity at a pH range of 3.0 to 7.0. These strains could use various sources of carbohydrates and nitrogen, derived from glucose, lactose, peptone, meat extract, and yeast extract. In addition, the analyses of biochemical characteristics revealed that X3 was capable of hydrolyzing starch and cellulose, while DL1 was not. Therefore, the results of this study suggested the potential of applying selected lignin-degrading bacterial strains on lignin treatments of agricultural wastes.

In this study, we investigated one of the most popular stochastic volatility pricing models, the Heston model, for European options. This paper deals with the implementation of a finite difference scheme to solve a two-dimensional partial differential equation form of the Heston model. We explain in detail the explicit scheme for the Heston model, especially on the boundaries. Some simple ideas to modify the treatment on the boundaries, which leads to a lower computational cost, are also stated. The paper also covers comparisons between the explicit solution and the semi-analytical solution.

In beekeeping, monitoring beehives plays an important role to make sure the health of bee colonies and to reduce negative effects that could happen for the colonies. A large number of studies have been carried out to improve the performance of monitoring beehives from the traditional manual methods. Especially, the application of Artificial Intelligence (AI) technologies in recent time has led to significant effects in the monitoring process. These new methods, however, have not yet been interested and applied in Vietnam. To understand the use of the AI-based technologies in automatic monitoring beehives, this paper provides a survey on the beehive monitoring system based on audio data and AI techniques. Opportunities and perspectives for the applications of these techniques in audio-based monitoring beehive in Vietnam are also discussed.