First record of Cantharellus minor from Vietnam with identification support from a combination of nrLSU and nrSSU phylogenetic analysis

Background: A previously identified sample XC02, which was collected from a pine forest (Pinus kesiya Royle ex Gordon), in Xuan Tho Commune, Da Lat, Lam Dong Province, Vietnam, was identified as Cantharellus minor based on morphology and nrLSU phylogeny analysis. Sequence analysis of multiple genes are becoming more and more common for phylogenetic analysis of mushrooms.Method: Total DNA was isolated from sample XC02. The primer NS1, NS4 were applied to amplify the target gene the nuclear ribosomal small subunit DNA (nrSSU). For phylogenetic analysis, individual and concatenated datasets (nrSSU and nrLSU-nrSSU) were constructed. Phylogenetic tree was constructed with MEGA 6.0 with a 1000 replicate bootstrap based on the neighbor joining, maximum likelihood, maximum parsimony method.  Results: A concatenated dataset containing a total of 14 sequences from Cantharellus, Craterellus (Cantharellaceae, Canthraellales) and Hydnum (Hydnaceae, Cantharellales) were constructed. For the specimen XC02, the phylogenies based on the first, second, and third datasets (nrLSU, nrSSU, and nrLSU-nrSSU) and the morphological analysis, reported in our previous study, strongly confirmed the identity of XC02 as Cantharellus minor.Conclusion: The combination between the morphological analysis and phylogenetic analysis is confirmed as the best approach for the identification of Cantharellus and other mushroom species that we collected in the Central Highlands, Vietnam.Keywords: nrLSU; Cantharellus, Cantharellus minor; nrSSU; nrLSU; phylogeny analysis; Vietna

Isolation and identification of triterpenoid compounds from Couroupita guianensis Aubl.

In this report, the extracts from the fruit and leaves of Couroupita guianensis were isolated using chromatographic methods and investigated for chemical composition. Four triterpenoid compounds were isolated and identified as betulinic acid, oleanolic acid, β-amyrin and friedelin. Their chemical structures were interpreted based on modern spectra such as MS, NMR and compared with previously published spectral data

Modelling nitrous oxide (N2O) emission from rice field in impacts of farming practices: A case study in Duy Xuyen district, Quang Nam province (Central Vietnam)

Nitrous oxide (N2O) emisison from paddy soil via the soil nitrification and denitrification processes makes an important contribution to atmospheric greenhouse gas concentrations. The soil N2O emission processes are controlled not only by biological, physical and chemical factors but also by farming practices. In recent years, modeling approach has become popular to predict and estimate greenhouse gas fluxes from field studies. In this study, the DeNitrification–DeComposition (DNDC) model were calibrated and tested by incorporating experimental data with the local climate, soil properties and farming management, for its simulation applicability for the irrigated rice system in Duy Xuyen district, a delta lowland area of Vu Gia-Thu Bon River Basin regions. The revised DNDC was then used to quantitatively estimate N2O emissions from rice fields under a range of three management farming practices (water management, crop residue incorporation and nitrogen fertilizer application rate). Results from the simulations indicated that (1) N2O emissions were significantly affected by water management practices; (2) increases in temperature, total fertilizer N input substantially increased N2O emissions. Finally, five 50-year scenarios were simulated with DNDC to predict their long-term impacts on crop yield and N2O emissions. The modelled results suggested that implementation of manure amendment or crop residue incorporation instead of increased nitrogen fertilizer application rates would more efficiently mitigate N2O emissions from the tested rice-based system.Phát thải nitơ ôxít (N2O) từ canh tác lúa nước (thông qua quá trình nitrat hóa và phản nitrat hóa) đóng góp đáng kể vào tổng lượng khí nhà kính có nguồn gốc từ sản xuất nông nghiệp. Quá trình phát thải N2O là không chỉ phụ thuộc vào các yếu tố sinh-lý-hóa học mà còn phụ thuộc các phương pháp canh tác. Trong những năm gần đây, việc ứng dụng mô hình hóa nhằm tính toán và ước lượng sự phát thải khí nhà kính ngày càng trở lên phổ biến. Trong nghiên cứu này, số liệu quan trắc từ thí nghiệm đồng ruộng và dữ liệu về đất đai, khí hậu, biện pháp canh tác được sử dụng để kiểm nghiệm và phân tích độ nhạy của mô hình DNDC (mô hình sinh địa hóa). Sau đó, mô hình được sử dụng để tính toán lượng N2O phát thải trong canh tác lúa nước dưới các phương thức canh tác khác nhau (về chế độ tưới, mức độ vùi phụ phẩm, bón phân hữu cơ, phân đạm) tại huyện Duy Xuyên, thuộc vùng đồng bằng thấp của lưu vực sông Vu Gia-Thu Bồn. Kết quả kiểm định chỉ ra rằng (1) sự phát thải N2O bị ảnh hưởng đáng kể do sự thay đổi chế độ tưới; (2) nhiệt độ tăng và lượng phân bón N tăng sẽ làm tăng phát thải N2O. Kết quả mô phỏng về tác động lâu dài (trong 50 năm) của các yếu tố đến năng suất cây trồng và phát thải N2O cho thấy: Việc sử dụng phân hữu cơ và phụ phẩm nông nghiệp thay thế cho việc bón phân đạm sẽ giúp giảm phát thải N2O đáng kể

Markhacanasin C, cycloartane triterpenoid from the leaves of <i>Markhamia stipulata</i> var. <i>canaense</i> V.S. Dang

<p>One new cycloartane triterpenoid, named markhacanasin C (<b>1</b>), together with three known triterpenoids, oleanolic acid (<b>2</b>), ursolic acid (<b>3</b>) and 6<i>β</i>,19<i>α</i>-dihydroxyursolic acid (<b>4</b>) were isolated by various chromatographic methods from the most cytotoxic fraction of the ethyl acetate extract of <i>Markhamia stipulata</i> var. <i>canaense</i> V.S. Dang leaves. Among them, <b>4</b> was reported for the first time from the genus <i>Markhamia</i>, while <b>2</b> and <b>3</b> were found for the first time from this species. Their structures were elucidated by IR, UV, HR-ESI-MS and NMR experiments. The cytotoxicity of isolated compounds (<b>3</b> and <b>4)</b> against three human cancer cell lines (HeLa, HepG2, and MCF-7) were evaluated. At the concentration of 100 μg/mL, <b>3</b> exhibited significant cytotoxic activity (86.36 ± 3.69%).</p

Antiproliferative, Anti-Inflammatory Activities, and Molecular Docking Studies of Secondary Metabolites from Macrosolen tricolor

In Vietnam, Macrosolen tricolor is used for the treatment of bloating, broken bones, cough, diarrhea, diuretic, rheumatism, and laxative effects. The study aimed to identify the in vitro antiproliferation and anti-inflammation of all fractions and purified compounds from the M. tricolor whole plants, as well as the in silico molecular docking of the potentially cytotoxic compounds. As the results, fractions (MTH.I, MTH.II, MTE.I, and MTE.II) strongly demonstrated antiproliferative properties against three tested cells, MDA-MB-231, RD, and HepG2 (IC50 values ranged from 4.00 ± 0.20 to 70.60 ± 1.44 μg/mL), as well as anti-inflammatory effects (IC50 values ranged from 4.45 ± 0.08 to 23.00 ± 1.18 μg/mL), whereas other fractions meaningfully evidenced selective cytotoxicity and/or anti-inflammation. Therefore, the phytochemical compositions of the active fractions were illuminated, leading to the characterization of eighteen compounds. Compounds (3–5) revealed the most cytotoxic effects towards all examined cells (IC50 values ranged from 6.88 ± 0.12 to 71.64 ± 1.17 μM) and the strongest anti-inflammatory properties (IC50 values of 16.30 ± 0.92, 7.31 ± 0.55, and 9.23 ± 0.60 μM, respectively). Compound 11 showed potential cytotoxicity against MDA-MB-231, RD, and HepG2 cells (IC50 values of 24.42 ± 0.28, 20.60 ± 0.25, and 3.20 ± 0.02 μM, respectively). Furthermore, compounds (4, 5, and 11) interacted with the active site of the apoptosis regulator Bcl-2 protein (PDB ID: 2O2F), were comparable to PAC, and were compatible with their anticancer activity. This project suggests that M. tricolor is a good source of natural antiproliferative and anti-inflammatory agents and contributes to understanding the biological activities of Macrosolen species in traditional Vietnamese medicine

Sociodemographic Factors, Sexual Behaviors, and Alcohol and Recreational Drug Use Associated with HIV Among Men Who Have Sex with Men in Southern Vietnam

A total of 2768 MSM participated in a survey in southern Vietnam. Univariate and multivariate logistic regression analyses were performed to determine predictors of HIV infection. The prevalence of HIV among MSM was 2.6 %. HIV infection was more likely in MSM who were older, had a religion, had engaged in anal sex with a foreigner in the past 12 months, previously or currently used recreational drugs, perceived themselves as likely or very likely to be infected with HIV, and/or were syphilis seropositive. MSM who had ever married, were exclusively or frequently receptive, sometimes consumed alcohol before sex, and/or frequently used condoms during anal sex in the past 3 months were less likely to be infected with HIV. Recreational drug use is strongly associated with HIV infection among MSM in southern Vietnam. HIV interventions among MSM should incorporate health promotion, condom promotion, harm reduction, sexually transmitted infection treatment, and address risk behaviors