Vietnam Journal of Biotechnology

Tobacco  mosaic  virus  (TMV)  and  cucumber  mosaic  virus  (CMV)  is  one  of  the  most  important  viral pathogens  capable of affecting  to many plant  species, such as tomato, potato, tobacco, peppe etc. In order to generate fransgenic tobacco plants resistant to both TMV and CMV, RNA interference  (RNAi) technology hasbeen applied in this study. A multi-fragment  of 625 bp - CPi (including  305 bp from  nucleotide  159 - 463 of TMV  cp gene  and  313 bp  from  nucleotide  315 -  627  of  CMV cp gene)  was used  to  construct  a  expression vector  containing T-CMV-CP  RNAi  in order to silence the CP gene of both TMV and CMV. This  construct was fransformed into tobacco plants (Nicotiana tabacum, cv. K326) via grobacterium tumefaciens.  The PCRT-PCR  and ELISA  analyses indicated that the CPi multi-fragment  was stably integrated  in tobacco genome and resulted in the absence of TMV and CMV in the inoculated transgenic lines. The resistant valuation of TO fransgenic tobacco  plants  after  three  times  challenge  with  TMV  and  CMV  revealed  that  34/48  (70.8%) fransgenic  lines were completely resistant to both studied vuuses.

Plant endophytes are an interesting group of microorganisms that colonize the internal tissues of living plants and do not cause any disease symptoms in the host plant. It exists in different parts of plants, such as roots, leaves, and stems, and significantly affects the formation of metabolic products in plants by promoting the accumulation of important secondary metabolites. The present study focused on analyzing the diversity and distribution of endophytic fungi related to different tissues from samples of the medicinal plant Dysosma difformis (Hemsl & E.H. Wilson) T.H. Wang collected in Ha Giang and Lai Chau, in which the isolates from roots were 27 strains (50.94%), 12 strains from stems (22.64%), and 14 strains from leaves (26.42%). Based on the isolates, we analyzed the fungal diversity through seven different diversity indices. The results showed that isolates’ diversity was similar to the endophytic fungal population in tissues of D. difformis distributed in different vegetation in Vietnam. Specifically, Shannon's index showed the highest diversity in roots (H′ = 2.673), followed by stems (H′ = 2.162) and leaves (H′ = 2,054). Similarly, species richness was highest in roots (Dmg = 4,551; Dmn = 3,079) and stem (Dmg = 4,024; Dmn = 3,175) and lowest in leaves (Dmg = 3.41; Dmn = 2,405). However, the Simpson diversity index showed that the endophytic fungal community was most abundance in leaves (1-D = 0.911), followed by stems (1-D = 0.897) and roots (1-D = 0.867). In addition, the Sorensen index of 0.615 shows the average similarity in species composition between the two sites, Ha Giang and Lai Chau. This is the first report on the diversity of endophytic fungi isolated from D. difformis, paving a potential way for screening endogenous fungal strains capable of producing important secondary compounds.

Opisthorchiasis is a zoonotic parasitic infection caused by small liver fluke species, Opisthorchis viverrini,O. felineus and Clonorchis sinensis, in the family Opisthorchiidae. Vietnam has both species, of which C.sinensis is distributed in the northern and O. viverrini in the central provinces. In addition to the mitochondrialgenomes, the ribosomal DNA sequences (rDNA) of these species are highly needed to obtain for providingmolecular markers in species identification, classification, phylogeny and evolutionary studies. In this study,the near/complete nucleotide sequences of ribosomal transcription units (rTU) from O. viverrini (Vietnamesesample), O. felineus (Russian sample) and C. sinensis (Vietnamese sample) were analyzed. All rTUs for threespecies were determined, which is 7,839 bp for O. viverrini, 6,948 bp for O. felineus and 7,296 bp for C.sinensis containing structures of 18S, ITS1, 5,8S, ITS2 and 28S. The IGS region was not obtained for all threespecies. In all three species, sequence analysis revealed 2 tandem repetitive elements of 47-48 bp/each in ITS1but not in ITS2. The nucleotide sequences of 18S, ITS1, ITS2 and 28S are valuable ribosomal markers that thisstudy provides for diagnosis, identification, taxonomic classification and population genetics. In conclusion,the rTU sequences for the three species of the family Opisthorchiidae have been identified and providesmolecular markers for the use of phylogenetic analysis for species/family classification in the superfamilyOpisthorchioidea and the class Trematoda.

Screening inhibitors of α-amylase and α-glucosidase from medicinal plants is a topic of interest in the world. Canna edulis Ker Gawl is an important rhizome plant belonging to the genus Canna of the family Cannaceae. It is traditionally used to treat many conditions such as gonorrhea, pain, bruises, diarrhea, hepatitis, chest pain and heart diseases. The potential of this plant in the treatment and prevention of diabetes has rarely been documented. This study reports, for the first time, α-amylase and α-glucosidase inhibiting effects and the phytochemical profile of the rhizome part of C. edulis.C. edulis rhizome was extracted with 96% ethanol, and then successively fractionated with n-hexane, ethyl acetate and water. α-amylase and α-glucosidase inhibiting assays were performed to investigate the enzyme inhibitory activities of the total extract and fractions. Qualitative phytoconstituents were analyzed using chemical reactions. The results showed that all extract and fractions had α-amylase and α-glucosidase inhibiting effects in a dose dependent manner. The ethyl acetate fraction exhibited the strongest inhibiting activities against both enzymes (IC50, 45.24 ± 2.90 and 90.09 ± 6.70 mg/mL for α-amylase and α-glucosidase inhibiting assays, respectively) and its effects were significantly higher than the positive control (p < 0.05). The water fraction showed the lowest effects. C. edulis rhizome contained abundant secondary metabolites including cardiac glycosides, cholesterols, glycosides, flavonoids, sterol and triterpenes, tannins, steroids, saponins, coumarins and proteins. All these secondary metabolites, except for saponin, were found in the ethyl acetate fraction. C. edulis rhizome could serve as a potential candidate to find novel anti-α-amylase and anti-α-glucosidase agents and to develop supplementary products for controlling hyperglycemia.

Probiotics have multiple beneficial effects on human health, including modulation of the immune system, inhibition of enteric pathogens, and prevention of metabolic disorders. Lactic acid bacteria (LAB) are the most common bacterial strains used for probiotic production. Among those, species belonging to the Lactobacillus acidophilus complex, especially L. gasseri, were well characterized and reported for probiotics. This study evaluated the potential probiotic characteristics of two L. gasseri strains (designed as VTCC 12791 and VTCC 12792) isolated from a pair of mother's breast milk and infant's feces. Both strains completely survived in the simulated gastric juice, highly tolerated the simulated intestinal juice (81-84%), strongly adhered to the HT-29 cell (23.5% for VTCC 12791 strain and 5.5% for VTCC 12792 strain), and had antagonistic activity against food-borne pathogens of Aeromonas dhakensis, Vibrio vulnificus, and Listeria monocytogenes, which demonstrated better beneficial properties than those of the commercial reference Lacticaseibacillus casei Shirota (LcS) strain. Additionally, both strains exhibited xanthine oxidase inhibitory activity (approximately 24%), which can lead to reducing serum uric acid. Regarding the safety aspect, the strains were sensitive to several antibiotics of ampicillin, vancomycin, tetracycline, chloramphenicol, erythromycin, and possessed alpha-hemolytic activity, which were similar to those of LcS strain. Our results suggested that L. gasseri VTCC 12791 and VTCC 12792 are potential candidates for producing probiotics and functional foods. Further in vivo studies are needed to prove their potential health benefits, especially in the treatment of hyperuricemia.

The researchs on the biomass spectra - a functional characteristic of biotic communities is still limited. In this study, the nematode biomass spectra in the bottom of Ba Lai estuary was investigated at six subtidal stations from the sea toward the upstream. The result showed that nematode biomass spectra ranged between -8 and 1 being significantly different between stations, and the lowest biomass of those spectras was in station BL4 (< 2 µg) which is upwardly closed to the Ba Lai dam. BL4 was also characterized by the lowest nematode abundance in the studied area. In addition, station BL3 downwardly closed to the dam exhibited low number of individuals. The heterogeneity in the nematode biomass spectra of BL3 and BL4 might due to the disturbance in the sedimentary environment of Ba Lai estuary related to the dam impact. This research again supports the important role of biomass spectra as bioindicator tool for biomonitoring and environmental quality assessment. Therefore, applying nematode biomass spectra is recommended for environmental assessment due to their advantages such as timesaving, not taxonomical expertise-requirement.

Vigna umbellata is an underutilized species in Vietnam, and more information about its nutritional values needs to be provided. This study investigated the nutritional composition and antioxidant activity of the seeds of 10 rice bean varieties collected from different districts of Son La province. Moisture content, ash and nutritional composition, including total protein, lipid, and carbohydrate were estimated. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, total phenolic content (TPC), and total flavonoid content (TFC) were carried out to assess the antioxidant activity. The results showed as follows: moisture content ranged from 0.44% to 1.23%, total ash values were obtained in the range between 38.46 and 45.72 mg/g DW, total protein content spread from 106.65 to 156.77 mg/g; total lipid varied from 7.37 to 11.90 mg/g, and total carbohydrate dominated the nutritional profile with 786.10 to 834.73 mg/g. Remarkably, there were significant differences (p < 0.05 using ANOVA) among the rice bean species from various districts of Son La province regarding moisture and protein content. Still, similar values were observed for other parameters (p > 0.05). The IC50 of the DPPH assay ranged from 259.06 µg/mL to 479.99 µg/mL, while the TPC varied from 2.85 to 4.98 mg GAE/g, and TFC values were in the range between 6.46 and 13.73 mg QE/g DW. Both TPC and TFC were significantly negatively correlated to antioxidant activity. This study is the first report on the nutritional compositions and antioxidant activity in the seeds of 10 rice bean varieties collected in Son La province. The findings in this study contribute to valorizing the V. umbellata species, which might be a promising plant as a low-priced staple food for ethnic people in mountainous regions.

Monkeypox (Mpox) is a viral zoonotic and human-to-human disease with no specific drug or treatment protocol targeting the monkeypox virus (MPXV). In the MPXV life cycle, viral kinase phosphorylation plays a crucial role in early morphogenesis in the cytoplasm, making inhibition of MPXV kinase a potential therapeutic approach for controlling Mpox. Hypericum sampsonii contains several bioactive compounds, such as hypericin and pseudohypericin, which are known for their antiviral properties. In this study, a computational investigation of the physicochemical properties of hypericin and pseudohypericin revealed drug-like characteristics. Pharmacokinetic predictions indicated that hypericin and pseudohypericin are non-toxic to the central nervous system, hepatic system, and cardiac system. Molecular docking results indicated a strong binding affinity of hypericin/pseudohypericin with MPXV thymidylate kinase. As a result, these compounds are being considered as potential Mpox control candidates.

Ovarian Tissue Cryopreservation (OTC) is a promising technique for reproductive preservation in women with cancer. Although this technique has been successfully applied in many Invitro Fertilization (IVF) centers worldwide, OTC has not been recently developed in Vietnam, and there are no publications of OTC. The study of OTC by vitrification at IVFMD, My Duc Hospital, was conducted from 2018 to 2023 with trial registration number NCT04666376. Ovarian tissues from each patient were divided into 3 groups: group 1, which consisted on fresh tissues as a control group; group 2, which consisted of vitrified tissues using the Ova Kit Type M (Kitazato, Japan); and group 3, which consisted of vitrified tissues using IVFMD medium. The findings showed that the rates of viable follicles and follicles with both healthy oocytes and CGs in groups 2 and 3 were significantly lower than in group 1, at [80.3% in group 1, 70% in group 2, and 65% in group 3] and [71.3% in group 1, 59.4% in group 2, and 58.3% in group 3] respectively (P < 0.05). The results aligned with previous findings due to the negative effects of cryopreservation. Moreover, it was illustrated that there was no change in the quality of tissue between the commercial medium and IVFMD’s medium in OTC.

Mucormycosis is an emerging fungal infection caused by many species belonging to the order Mucorales. The lack of effective therapies to treat this disease is due to our limited understanding of its pathogenesis. Chitin is one of the fungal-specific components of the cell wall. In fungi, chitin synthase and chitin deacetylase are the key enzymes involved in chitin biogenesis. The RNAi mechanisms have been well-studied in the fungus Mucor-lusitanicus, a model organism for mucormycosis studies. The RNAi technique has been previously applied to study gene function. In this study, two chitin synthase-encoding genes (chs1 and chs2) were identified using transcriptomic data. Approximately 1 kb of DNA fragments of the target genes were amplified and cloned into the pMAT1812 vector to generate the corresponding RNAi plasmids. Initial screening by colony PCR identified 3/10 and 1/10 potential colonies that might contain the RNAi plasmids. One plasmid for each clone was selected and named pAT63 and pAT64, corresponding to the chs1 and chs2 genes, respectively. The validation of these recombinant RNAi plasmids using different restriction enzymes (NotI - PvuII and SalI - PstI for plasmids pAT63 and pAT64, respectively) showed the expected results. The DNA sequencing of the plasmids pAT63 and pAT64 using specific primers validated the results of the screening process. These RNAi plasmids can be used to suppress the expression of the target genes. The silencing mechanism of the target genes will be triggered by the expression of the RNAi plasmids. This approach allows us to study the function of the chitin synthase-encoding genes in this fungus.