SÀNG LỌC HOẠT TÍNH KHÁNG OXY HÓA CỦA MỘT SỐ LOÀI RONG NÂU SARGASSUM Ở KHÁNH HÒA, VIỆT NAM

Bài báo này thể hiện kết quả sàng lọc hoạt tính chống oxy hóa của 5 loài rong nâu S. angustifolium, S. aemulum, S. assimile, S. feldmanii và S. ilicifolium ở tỉnh Khánh Hòa. Hoạt tính chống oxy hóa được đánh giá dựa trên các hoạt tính chống oxy hóa tổng, khử Fe và DPPH. Đồng thời cũng chỉ ra hàm lượng phlorotannin/ polyphenol tương ứng ở trong các loài rong này. Những loài này được thu mẫu vào thời gian thành thục sinh sản của chúng. Kết quả cho thấy hàm lượng phlorotannin/ polyphenol ở rong S. angustifolium là cao nhất. ở 5 loài nghiên cứu, hoạt tính khử Fe thể hiện mạnh hơn các hoạt tính khác, hoạt tính khử Fe của S. angustifolium là cao nhất. Hoạt tính bắt gốc tự do DPPH dao động trong khoảng 50% - 96%

Two new additions to the flora of Vietnam

Among the studied specimens collected from Son Tra Nature Reserve, Vietnam, two new taxa: Oxalis barrelieri L. (Oxalidaceae) and Glochidion acuminatum var. siamense Airy Shaw (Phyllanthaceae) which forms new records to the flora of Vietnam. Taxonomic description, habitat, distribution and uses, and color photographs of both taxa are provided

Partial purification and characterization of a superoxide distimutase (SOD1) from black tiger shrimps Penaeus monodon

Superroxide dismutase (SOD, EC.1.15.1.1) is the enzyme which dismutates superoxide radicals and plays an important role in protection of living cells against oxidative stress. SOD is also involved in immune response in shrimps. In this study, it was found that the total SOD activity of black tiger shrimp muscular tissues is 10 fold higher than that of the haemolymph, however, the specific activity of SOD in the shrimp haemolymph is 9.2 fold higher than that of muscular tissues. By using active gel electrophoresis, 2 different SOD forms were found in black tiger shrimps (one in muscular tissues and two in haemolymph).Using DE-52 cellulose and Q-Sepharose ion exchange column chromatography, one SOD (SOD1) from black tiger shrimp haemolymph was partially purified, and its purity was 31.2 times higher than that of the starting haemolymph. The SOD1 was shown to have mainly one protein band of approximately 24 kDa on SDS-PAGE. SOD1 was most active at 45oC and pH of 5.5. At a concentration of 5 mM, Mn2+ strongly activated SOD1 (up 200% activity), Ca2+ và Zn2+ could increase approximately 20% activity while Cu2+ inhibited more than 60% ativity of the enzyme.

The Virome of Acute Respiratory Diseases in Individuals at Risk of Zoonotic Infections

The ongoing coronavirus disease 2019 (COVID-19) pandemic emphasizes the need to actively study the virome of unexplained respiratory diseases. We performed viral metagenomic next-generation sequencing (mNGS) analysis of 91 nasal-throat swabs from individuals working with animals and with acute respiratory diseases. Fifteen virus RT-PCR-positive samples were included as controls, while the other 76 samples were RT-PCR negative for a wide panel of respiratory pathogens. Eukaryotic viruses detected by mNGS were then screened by PCR (using primers based on mNGS-derived contigs) in all samples to compare viral detection by mNGS versus PCR and assess the utility of mNGS in routine diagnostics. mNGS identified expected human rhinoviruses, enteroviruses, influenza A virus, coronavirus OC43, and respiratory syncytial virus (RSV) A in 13 of 15 (86.7%) positive control samples. Additionally, rotavirus, torque teno virus, human papillomavirus, human betaherpesvirus 7, cyclovirus, vientovirus, gemycircularvirus, and statovirus were identified through mNGS. Notably, complete genomes of novel cyclovirus, gemycircularvirus, and statovirus were genetically characterized. Using PCR screening, the novel cyclovirus was additionally detected in 5 and the novel gemycircularvirus in 12 of the remaining samples included for mNGS analysis. Our studies therefore provide pioneering data of the virome of acute-respiratory diseases from individuals at risk of zoonotic infections. The mNGS protocol/pipeline applied here is sensitive for the detection of a variety of viruses, including novel ones. More frequent detections of the novel viruses by PCR than by mNGS on the same samples suggests that PCR remains the most sensitive diagnostic test for viruses whose genomes are known. The detection of novel viruses expands our understanding of the respiratory virome of animal-exposed humans and warrant further studies

ĐA DẠNG DI TRUYỀN QUẦN THỂ CÁ CHÌNH HOA (Anguilla marmorata) TẠI QUẢNG TRỊ

This study was conducted to evaluate the population genetic diversity of the wild Anguilla marmorata in Quang Tri province by comparing the DNA sequences of the mitochondrial control region (CR) gene with those of other giant mottled eel populations in the world. The results indicate that the genetic distance between individuals in the Quang Tri population ranged from 0 to 0.261, with an average of 0.024. Among 31 individuals, there were 203 distinct polymorphism sites (S), which led to 209 mutation sites (Eta) and 31 different haplotypes. The average number of distinct nucleotides (k) was 29,299. The nucleotide diversity factor (Pi) accounted for 26.09 × 10–3, and the minimum number of recombination processes (Rm) in the population was 51 events. The majority of eel samples collected at the site had close genetic relationships with those of the North Pacific population (27/31 individuals), and four eel samples had close genetic relationships with those of the South Pacific population. The finding of the four giant mottled eels in Quang Tri belonging to the South Pacific population is considered a significant result of this study.Nghiên cứu này được thực hiện nhằm đánh giá đa dạng di truyền của quần thể cá Chình hoa (Anguilla marmorata) tự nhiên tại tỉnh Quảng Trị dựa trên việc so sánh trình tự DNA của vùng gene điều khiển CR (control region) ty thể với các quần thể cá Chình hoa trên thế giới. Kết quả cho thấy khoảng cách di truyền giữa các cá thể trong quần thể dao động từ 0 đến 0,261, đạt trung bình 0,024. Trong 31 cá thể, 203 vị trí đa hình tách biệt (S) đã tạo ra 209 vị trí đột biến (Eta) với 31 kiểu haplotype khác nhau. Số lượng các nucleotide khác biệt trung bình là 29.299 (k); hệ số đa dạng nucleotide chiếm 26,09 × 10–3 (Pi); số lượng tối thiểu để xẩy ra quá trình tái tổ hợp (Rm) trong quần thể tương ứng với 51 sự kiện. Phần lớn cá thể thu được tại Quảng Trị có quan hệ di truyền gần gũi với quần thể cá Chình hoa Bắc Thái Bình Dương (27/31 cá thể) và 4 cá thể có mối quan hệ di truyền gần gũi với quần thể Nam Thái Bình Dương. Việc phát hiện các cá thể Chình hoa tại Quảng Trị có di truyền gần gũi với các cá thể thuộc Nam Thái Bình Dương được xem như một điểm đáng chú ý trong nghiên cứu này

The Virome of Acute Respiratory Diseases in Individuals at Risk of Zoonotic Infections

The ongoing coronavirus disease 2019 (COVID-19) pandemic emphasizes the need to actively study the virome of unexplained respiratory diseases. We performed viral metagenomic next-generation sequencing (mNGS) analysis of 91 nasal-throat swabs from individuals working with animals and with acute respiratory diseases. Fifteen virus RT-PCR-positive samples were included as controls, while the other 76 samples were RT-PCR negative for a wide panel of respiratory pathogens. Eukaryotic viruses detected by mNGS were then screened by PCR (using primers based on mNGS-derived contigs) in all samples to compare viral detection by mNGS versus PCR and assess the utility of mNGS in routine diagnostics. mNGS identified expected human rhinoviruses, enteroviruses, influenza A virus, coronavirus OC43, and respiratory syncytial virus (RSV) A in 13 of 15 (86.7%) positive control samples. Additionally, rotavirus, torque teno virus, human papillomavirus, human betaherpesvirus 7, cyclovirus, vientovirus, gemycircularvirus, and statovirus were identified through mNGS. Notably, complete genomes of novel cyclovirus, gemycircularvirus, and statovirus were genetically characterized. Using PCR screening, the novel cyclovirus was additionally detected in 5 and the novel gemycircularvirus in 12 of the remaining samples included for mNGS analysis. Our studies therefore provide pioneering data of the virome of acute-respiratory diseases from individuals at risk of zoonotic infections. The mNGS protocol/pipeline applied here is sensitive for the detection of a variety of viruses, including novel ones. More frequent detections of the novel viruses by PCR than by mNGS on the same samples suggests that PCR remains the most sensitive diagnostic test for viruses whose genomes are known. The detection of novel viruses expands our understanding of the respiratory virome of animal-exposed humans and warrant further studies.Peer reviewe

The status of southern white-cheeked gibbon (Nomascus siki) in Truong Son key biodiversity area

The Southern white-cheeked crested gibbon, Nomascus siki, is an endemic primate to Vietnam and Laos, and has been identified as a nationally and globally endangered species (EN). However, little information is known on the status of the species in Vietnam generally and in the Truong Son key biodiversity area (Truong Son KBA) particularly. In order to explore the current status of the species in the Truong Son KBA, we conducted field surveys in 2018 and 2019. Analysis of the survey data shows 149 groups of gibbon in the 4 study areas. Combined with results of similar-techniqued survey in 2016 on the same species in Khe Nuoc Trong forest, we identified at least 252 gibbon groups and estimated 425 gibbon groups in the entire Truong Son KBA. These gibbon groups are mainly distributed in medium-rich evergreen closed forests in mountainous areas of the west Truong Son KBA, adjacent to the Vietnam-Laos border.

Evaluation of the Luminex xTAG Respiratory Viral Panel FAST v2 assay for detection of multiple respiratory viral pathogens in nasal and throat swabs in Vietnam.

BACKGROUND: Acute respiratory infections (ARI) are among the leading causes of hospitalization in children ≤5 years old. Rapid diagnostics of viral pathogens is essential to avoid unnecessary antibiotic treatment, thereby slowing down antibiotic-resistance. We evaluated the diagnostic performance of the Luminex xTAG Respiratory Viral Panel FAST v2 against viral specific PCR as reference assays for ARI in Vietnam. METHODS: Four hundred and forty two nose and throat swabs were collected in viral transport medium, and were tested with Luminex xTAG Respiratory Viral Panel FAST v2. Multiplex RT-PCR and single RT-PCR were used as references.    Results: Overall, viral pathogens were detected in a total count of 270/294 (91.8%, 95% CI 88.1-94.7) by the Luminex among reference assays, whilst 112/6336 (1.8%, 95% CI, 1.4-2.1) of pathogens were detected by the Luminex, but not by reference assays. Frequency of pathogens detected by Luminex and reference assays was 379 and 292, respectively. The diagnostic yield was 66.7% (295/442, 95%CI 62.1-71.1%) for the Luminex assay and 54.1% (239/442, 95% CI, 49.3-58.8%) for reference assays. The Luminex kit had higher yields for all viruses except influenza B virus, respiratory syncytial virus, and human bocavirus. High agreements between both methods [mean (range): 0.91 (0.83-1.00)] were found for 10/15 viral agents. CONCLUSIONS: The Luminex assay is a high throughput multiplex platform for rapid detection of common viral pathogens causing ARI. Although the current high cost may prevent Luminex assays from being widely used, especially in limited resource settings where ARI are felt most, its introduction in clinical diagnostics may help reduce unnecessary use of antibiotic prescription

Viral Metagenomic Analysis of Cerebrospinal Fluid from Patients with Acute Central Nervous System Infections of Unknown Origin, Vietnam.

Central nervous system (CNS) infection is a serious neurologic condition, although the etiology remains unknown in >50% of patients. We used metagenomic next-generation sequencing to detect viruses in 204 cerebrospinal fluid (CSF) samples from patients with acute CNS infection who were enrolled from Vietnam hospitals during 2012-2016. We detected 8 viral species in 107/204 (52.4%) of CSF samples. After virus-specific PCR confirmation, the detection rate was lowered to 30/204 (14.7%). Enteroviruses were the most common viruses detected (n = 23), followed by hepatitis B virus (3), HIV (2), molluscum contagiosum virus (1), and gemycircularvirus (1). Analysis of enterovirus sequences revealed the predominance of echovirus 30 (9). Phylogenetically, the echovirus 30 strains belonged to genogroup V and VIIb. Our results expanded knowledge about the clinical burden of enterovirus in Vietnam and underscore the challenges of identifying a plausible viral pathogen in CSF of patients with CNS infections

Farming systems in the sandy area of the Thua Thien Hue Province, Central Vietnam, survey of socio-economic situation and constraints identified by farmers

peer reviewe