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Cordyceps militaris is an insect parasitic fungus with high medicinal value similar to Cordyceps sinensis and has great economic value. Ensuring the balance between the biomass and the bioactive potential of C. militaris plays an important role in the development of quality products from this medicinal fungus. In this study, nitrogen sources (fresh silkworm pupae, peptone, yeast extract) with different concentrations were used to evaluate the effect on yield, morphology and content of cordycepin, adenosine of C. militaris. The results showed that the N1 medium using 20 g\L fresh silkworm pupae, 0.5g\L KH2PO4 and 0.5g\L MgSO4 gave the highest yield and active ingredient content, with cordycepin yield of 17.01 mg\jar. Adding carbon sources (glucose and sucrose) at concentrations (10, 20, 40 g\L) to N1 medium can shorten the time of filamentous spreading and the time of fruit body formation, but significantly reduce cordycepin content. This result has important implications for medium optimization for C. militaris culturing.

Chomosome number and karyotypes of the North taro germplasm collections maintained at The Plant Resources Center were studied for the database of taro germplasms and to assess genetic diversity in taro (Colocasia esculenta Schott) in Vietnam. The results showed that, most of the 250 accessions of collections discovered are diploid (2n = 2x = 28), accounting for 77,2%, only 22,8% of the germplasm collections are triploid (2n = 3x = 42). The frequency of distribution of diploid and triploid taros between the natural geographic sub-region of the Northwest mountainous and the Northeastern mountainous and midland sub-region is similar. The northern taro germplasm is being conserved is cytogenetic diversity expressed in both chromosome sets (diploid and triploid) and 5 different karyotypes. Three of the five karyotypes (diploid karyotype 11 m + 3 sm, 10 m + 3 sm + 1st, and triploid karyotype, 10 m + 4 sm) were detected in the study were not still reported in taro of Vietnam, therefore added data on the diversity of karyotypes in the taro species of our country. The detailed analysis of chromosomes obtained in this study has provided cytogenetic data, contributing to enriching the taro germplasm database, which is meaningful in conservation and evolutionary research, and planning of breeding programs for new cultivar production of this crop to grow in different agroclimatic environments.

Genetics is one of the important topics in the high school biology curriculum. Genetics has been taught in the subject of biology at grade 9 and grade 12. To investigate the general understanding of genetics of high school students, a survey was carried out and got responses from participants of 901 high school students across the country. The data for the average score was 3.3; median 3.0; scores ranging from 0.33 to 8.33. The data analyses showed that there was no significant difference in the results between urban and rural regions. The general knowledge of genetics of high school students was low. In general, scores of students in gifted schools were higher than in non-gifted schools. In the group of gifted schools, the biological group gave higher results than others. In general, the students tend to choose the subject Biology and have high average scores, also got survey scores higher than those of other groups. Those results contribute to clarifying the reality of learning Biology in general and Genetics in particular of high school students, contributing to the basis for educational administrators to provide more appropriate educational policies.

n-Hexane, ethyl acetate, and butanol fractions from methanol extract of Vietnamese Phellinus baumii fruiting body consisted of phenolics, flavonoids, and terpenoids. Ethyl acetate and butanol fractions showed a high level of total phenolics. Ethyl acetate fractions possessed the highest phenolic content (532.96 ± 19.95 mg GAE\g), accounting for approximately 53% fraction dry weight. Free radical DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging capacity of all fractions correlated with their total phenolic content. Ethyl acetate fraction exhibited the strongest capacity with an IC50 value of 0.059 mg\mL, equivalent to nearly 50% of ascorbic acid’s capacity. Its ferric reducing power was off more than half of quercetin and acid ascorbic at the concentration of 0.2 mg\mL. Ethyl acetate also had remarkable α-amylase inhibitory activity (IC50= 0.38 mg\mL). The results suggested P. baumii fruiting body as a potent source for antioxidative and α-amylase inhibitory compounds.

Mucormycosis is an uncommon but life-threatening invasive fungal infection, mostly occurs in immunocompromised patients. Lacking the appropriate antifungal drugs is one of the reasons that lead to difficulties in the management of mucormycosis. Curcuma longa has been used traditionally and widely to treat various diseases, including fungal infections. In the search for novel antifungal compounds from natural resources, we evaluated the effect of rhizome crude extract of C. longa on Mucor circinelloides – a causal agent of mucormycosis. The results of screening, using broth dilution method and agar-well diffusion method, showed that the C. longa extract exhibited promising antifungal activity against the fungus M. circinelloides. In liquid medium, C. longa extract decreased the ability of spore germination and the speed of hyphae formation of M. circinelloides decreased by up to approximately 70% and 90%, respectively. Besides, in a solid medium, the crude extract presented similar activity with amphotericin B (400 μg\mL) in decreasing the growth of M. circinelloides by nearly 77%. Moreover, the extract of C. longa also likely to induce the yeast-like type of growth of the dimorphic M. circinelloides in the early stage. These results suggest the plant could be a potential source for further study on biochemical components and the mechanism of its antifungal activity.

Vibrio parahaemolyticus is a gram-negative bacterium which has been widely reported as the cause for hepatic and kidney necrosis in fishes, especially species of high economic value, in many regions across the world. Five pathogenic strains of V. parahaemolyticus were isolated from seawater samples collected in Thanh Hoa and Nghe An regions, Vietnam. All those strains were characterized by well-known morphological and biochemical characteristics of V. parahaemolyticus. Furthermore, we identified the presence of two common found virulent genes in V. parahaemolyticus (i.e. toxR và tlh) from all isolated strains while the other two genes (i.e. tdh and trh) were missing. Experimental results indicated LD50 values of isolated strains diverged from 105.73 to 107.28 on tilapia (Oreochromis niloticus) and 104.15 to 105.15 on zebrafish (Danio rerio). Then, the strain with the lowest LD50 value, named DH64.1, was selected for producing an inactivated vaccine by using formaldehyde. Consequently, the inactivated vaccine was injected on tilapia with survival rate 100% and the lack of any pathogenic symptom. Finally, vaccinated fish that were challenged with DH64.1 strain at three different challenge doses (i.e. 106, 107, 108 CFU\mL). After a 15 days post-vaccination, the relative percentage survival (RPS) of the vaccine was around 88.66-100%.