Nguyen Thi Lien

Prevalence of bee viruses among Apis cerana populations in Vietnam

We studied the prevalence and distribution of seven honey bee viruses, namely: acute bee paralysis virus (ABPV); cloudy wing virus (CWV); Israeli acute paralysis virus (IAPV); Kashmir bee virus (KBV); sacbrood virus (SBV); black queen cell virus (BQCV); and deformed wing virus (DWV), in healthy colonies from ten provinces in Vietnam. Colonies from each apiary were randomly selected to check viral infection. To confirm virus infection, samples were tested by Reverse Transcription Polymerase Chain Reaction using specific primer pairs. The positive products were sequenced and compared with the reference sequences using Basic Local Alignment Search Tool for molecular confirmation. In 360 Apis cerana samples, we found that the most prevalent virus was SBV (in 18.33% of samples), followed by BQCV (6.11%) and DWV (3.33%). The other four viruses, ABPV, CWV, IAPV, and KBV, were not detected in any sample. Infection rates were higher in adult bees than in larvae. The prevalences of SBV, BQCV, and DWV were 25.00, 10.56, and 6.11% in adult bees, and 11.67, 1.11, and 0.56% in larvae, respectively. The occurrence of BQCV and DWV varied across geographic regions. BQCV occurred mainly in the northern provinces, while DWV was predominant in the southern provinces. SBV, however, was found in all sampled provinces and exhibited similar infection rates. In adult bees, co-infection rates of BQCV with SBV or DWV were 2.22 and 0.60%, respectively.

Comparative Genomic Analysis for Genetic Variation in Sacbrood Virus of Apis cerana and Apis mellifera Honeybees From Different Regions of Vietnam

Abstract Sacbrood virus (SBV) is one of the most common viral infections of honeybees. The entire genome sequence for nine SBV infecting honeybees, Apis cerana and Apis mellifera, in Vietnam, namely AcSBV-Viet1, AcSBV-Viet2, AcSBV-Viet3, AmSBV-Viet4, AcSBV-Viet5, AmSBV-Viet6, AcSBV-Viet7, AcSBV-Viet8, and AcSBV-Viet9, was determined. These sequences were aligned with seven previously reported complete genome sequences of SBV from other countries, and various genomic regions were compared. The Vietnamese SBVs (VN-SBVs) shared 91–99% identity with each other, and shared 89–94% identity with strains from other countries. The open reading frames (ORFs) of the VN-SBV genomes differed greatly from those of SBVs from other countries, especially in their VP1 sequences. The AmSBV-Viet6 and AcSBV-Viet9 genome encodes 17 more amino acids within this region than the other VN-SBVs. In a phylogenetic analysis, the strains AmSBV-Viet4, AcSBV-Viet2, and AcSBV-Viet3 were clustered in group with AmSBV-UK, AmSBV-Kor21, and AmSBV-Kor19 strains. Whereas, the strains AmSBV-Viet6 and AcSBV-Viet7 clustered separately with the AcSBV strains from Korea and AcSBV-VietSBM2. And the strains AcSBV-Viet8, AcSBV-Viet1, AcSBV-Viet5, and AcSBV-Viet9 clustered with the AcSBV-India, AcSBV-Kor and AcSBV-VietSBM2. In a Simplot graph, the VN-SBVs diverged stronger in their ORF regions than in their 5′ or 3′ untranslated regions. The VN-SBVs possess genetic characteristics which are more similar to the Asian AcSBV strains than to AmSBV-UK strain. Taken together, our data indicate that host specificity, geographic distance, and viral cross-infections between different bee species may explain the genetic diversity among the VN-SBVs in A. cerana and A. mellifera and other SBV strains.

Study on active tectonic faults using soil radon gas method in Viet Nam

This paper presents the results of soil radon gas measurement in three areas, including Thac Ba and Song Tranh 2 hydropower plants, and the planned locations of the nuclear power plants Ninh Thuan 1&2 using solid-state nuclear track detectors (SSNTD) with the aim of clarifying the activity of tectonic faults in these areas. The activity of tectonic faults was assessed through radon activity index KRn (the ratio between anomaly and threshold), which was divided into 5 levels as follows ultra-high (KRn> 10), high (10≥KRn> 5), high (5≥KRn> 3), medium (3≥KRn> 2) and low (KRn≤2). Soil radon gas measurement results showed that in the radon gas concentrations in the Thac Ba hydropower plant area ranged from 72 Bq/m to 273.133 Bq/m and maximum radon activity index KRn reached 9.75 (high level). High KRn indexes show Chay River fault active in recent time and the sub-meridian distribution of Rn anomalies suggested a right-slip motion of the fault. Rn concentrations in the Ninh Thuan 1&2 areas ranged from 6 Bq/m to 52.627 Bq/m, however, the KRn indexes were mostly low (KRn≤3) and the highest value was only 3.42, suggesting that expression of activity of the tectonic faults in this region is not clear, even no expression of fault activity. In the Song Tranh 2 hydropower plant and adjacent areas, radon concentrations ranged from 29 Bq/m to 77.729 Bq/m and maximum KRn index was 20.16 (ultra-high level). The faults having clearer activity expression are Hung Nhuong Ta Vy, Song Tra Bong and some high order faults, especially the northwest southeast segments of these faults or their intersections with the northwest southeast faults. In addition, the high values KRn in the mentioned intersections can be evidenced for the activeness of northwest southeast faults at the present time. The studies on active faults using soil radon gas method were performed in areas with very different geological and structural features, but the results are well consistent with the results of previous investigations obtained by other methods. It confirmed the effectiveness and capability of soil radon gas geochemistry applying to study active tectonic faults.

A study on Arbuscular Mycorrhiza diversity in soil and orange roots sampled from Quy Hop, Nghe An

Arbuscular Mycorrhyza Fungi (AMF) is the common type of symbiotic between mycorrhiza fungi and plants. They have an important role for the growth of plants, especially in bad environmental conditions. In this paper, we reported results of isolation and identification of AMF species in soil and orange roots sampled in Quy Hop, Nghe An province. The results showed that there were 16 AMF species belonging to six genera namely Acaulospora , Entrophospora , Glomus , Sclerocystis , Glomites and Gigaspora in the collected samples from different soil horizons (0-20 cm, 20-40 cm and 40-60 cm) and roots of three orange cultivars, such as Xa Doai, Van Du and V2. The distribution of AMF on roots of three orange cultivars and three soil horizons were significantly different. The role of AMF was evaluated throught the test to determine the infection of AMF into the young orange trees. Results revealed that the trees which were infected with AMF had roots longer and more number of roots.