Vietnam Journal of Biotechnology

Hiện nay, vi nhân giống Salem vẫn còn gặp nhiều khó khăn như: lá cây in vitro và ex vitro dễ bị hoại tử do nấm, vi khuẩn và virus nội sinh; cây con phát triển chậm, tỉ lệ sống của cây con thấp ở giai đoạn vườn ươm. Nghiên cứu này bước đầu thử nghiệm vật liệu nano sắt hóa trị 0 (nZVI) thay thế cho Fe-EDTA trong môi trường nuôi cấy in vitro cây Salem, một loại cây hoa cắt cành có giá trị cao trên thế giới, nhằm đánh giá khả năng nhân nhanh chồi, sinh trưởng cây con in vitro và thuần hóa ex vitro của cây. Kết quả thu được cho thấy, khi gia tăng nồng độ nZVI (10-200 μM) bổ sung vào môi trường cảm ứng phát sinh chồi với 0,4 mg/L BA, 0,2 mg/L NAA, hệ số nhân chồi tăng so với sử dụng Fe-EDTA sau 5 tuần nuôi cấy. Trong giai đoạn ra rễ, tốc độ tăng trưởng của cây con trên môi trường ½ MS bổ sung nZVI với 0,4 mg/L NAA kém hơn các cây trên môi trường sử dụng Fe-EDTA. Tuy nhiên, sau 4 tuần nuôi trồng ngoài vườn ươm, các cây con in vitro trên môi trường bổ sung nZVI cho hiệu quả tăng trưởng và tỷ lệ sống cao vượt trội so với đối chứng sử dụng Fe-EDTA. Nano sắt với nồng độ 50 μM bổ sung vào môi trường nuôi cấy cho hệ số nhân chồi in vitro, chiều cao cây con, trọng lượng tươi, chiều dài rễ, chỉ số chlorophyll và tỷ lệ sống sót ngoài điều kiện vườm ươm tốt nhất (8,33 chồi; 11,67 cm; 2,89 g; 5,67 cm; 24,3; 99,17%; tương ứng). Nghiên cứu này cho thấy rằng việc sử dụng nano sắt trong môi trường vi nhân giống cho hiệu quả nhân nhanh và chất lượng cây giống ex vitro tốt hơn so với sử dụng muối sắt Fe-EDTA.

The trace element arsenic naturally presents in the environment. Arsenic is the essential factor to the human body at low level, however it causes environmental pollution and have negative effects to health at high level. Recently, arsenic contamination as well as its effects on public health, especially infants and children is increasingly becoming important and serious issues in worldwide. Glutathione S-transferase omega-1 (GSTO1) is a phase II enzymatic detoxification of xenobiotics in variety of animals including humans; to catalyze the arsenic methylation. The difference of urinary arsenic component in each individual may relate to the genetic polymorphism. To evaluate the variations of single nucleotide polymorphisms of GSTO1, PCR-RFLP technology was ultilized. Single nucleotide polymorphisms (SNPs) genotype of 150 cohort blood samples at GSTO1 Thr->Asn (rs15032), GSTO1 Ala->Val (rs11509439) and GSTO1 Ala->Asp (rs4925) were detected. The association between GSTO1 polymorphisms and prenatal arsenic exposure was evaluated by statistical analysis such as SPSS software version 20, t-test and oneway ANOVA. The results showed that GSTO1 Ala->Asp (rs4925) was statistically associated with MMA/iAs (p = 0.041). Differences between ratio of MMA/iAs and genotypes were checked by Tukey-Kramer method, along with oneway ANOVA showed that Individuals taking the AA genotype had higher MMA/ iAs ratio than individuals carrying the CC genotype, with a statistically significant association (p = 0.044), also clearly higher than the individuals carrying AC genotype, significant at p = 0.046. Therefore, it is possible that individuals carrying the AA genotype in the polymorphism have higher arsenic excretion than individuals with CC and AC genotypes

Fluoxetine (FLX), a widely used antidepressant primarily acting as a selective serotonin reuptake inhibitor, has been shown to exhibit other mechanisms of action in various cell types. Cyclic adenosine monophosphate (cAMP) is a second messenger used for intracellular signal induction. Cyclic AMP is a nucleotide synthesized within the cell from adenosine triphosphate by the adenylyl cyclase enzyme, and is inactivated enzymatically to 5′AMP by hydroxylation with a group of enzymes called phosphodiesterase. The aim of this study was to determine the effects of FLX on MLTC-1 Leydig cells on intracellular cyclic AMP response to forskolin (FSK). MLTC-1 cells were incubated at 37°C in media supplemented with or without different doses of FLX (0, 0.156, 0.3125, 0.625, 1.25, 2.5, 5 and 10 µM). We then looked for how the concentration of FLX for a short-time (2 hours) and a long-time (24 hours) affects the concentration of intracellular cyclic AMP response to FSK and ATP levels on MLTC-1 cells. Our results show that FLX decreased the intracellular cAMP response to FSK depending on FLX concentration. FLX decreased significantly cAMP levels only at 10 µM after 2 hours of incubation but after 24 hours of incubation FLX caused an effect on cAMP levels at 5 µM and at 10 µM. Moreover, as expected, FLX also caused a decline of steroidogenesis, which is under the control of cAMP and ATP levels in the cells. Taken together, these findings demonstrate that the inhibition of cAMP synthesis by FLX is dose-dependent, and that FLX also inhibited hormone-induced steroidogenesis in MLTC-1 cells.

Six microsatellites were used to characterize genetic diversity in three purebred giant freshwater prawn (Macrobrachium rosenbergii) strains that originated from a diallel cross among two wild Vietnamese strain (Dong Nai and Mekong) and a third domesticated Hawaiian strain. All three purebred strains showed relatively high levels of genetic diversity with average number of alleles per locus (A) ranging from 13 to 15. Average observed (Ho) and expected (He) heterozygosities across loci were 0.84 to 0.89 and 0.87 to 0.89, respectively. Microsatellite data from the three purebred strains were pooled together as a basis for estimating the levels of genetic diversity in an synthetic hatchery population and this compared with data for genetic diversity in the three wild populations combined. No significant differences were observed in the relative levels of genetic diversity between the two combined populations. Average A, Ho, and He for the experimental vs. wild reference populations were 24.33 vs. 24.33, 0.87 vs. 0.90, and 0.94 vs. 0.95, respectively. Therefore, an experimental population formed by combining the genetic resources from three purebred strains showed non-significant loss of genetic diversity as a consequence of domestication process. Thus such a synthetic line can provide an important genetically diverse resource for the planned development of GFP culture in Vietnam.

The reverse transcriptase-polymerase chain reaction (RT-PCR) was applied for detection of the strawberry crinkle vims (SCV) and strawberry mild yellow edge vims (SMYEV) diseases on three strawberry cultivars: "My Da", "My Huong" and "Phap". The in vitro leaves of these three strawberry cultivars were used for this research. Three different culture media were used. Calli were induced on the MS medium containing 1 mg/l TDZ, 0.1 mg/l 2,4-D, 30 g/l sucrose and 8 g/l agar (1); shoots were regenerated on MS medium containing 0.2 mg/l BA, 30 g/l sucrose and 8 g/l agar (2); roots were formed on MS medium containing 5 ml/1 B5 vitamin, 30 g/l sucrose and 8 g/l agar (3). The RNA extraction from leaf tissues according to the method of Mazzara and James (2000) and then, the extracted RNA transposition into RT-PCR using the StrataScript® One-Tube RTPCR Kit of ITS Vietnam. In this research, two primer pairs SCIDFW-SCIDRV and SMlDFW-SMlDRV were used for the detection of these virases by RT-PCR. The amplified products had expected sizes: 345 bp and 271 bp, respectively. We found that the RT-PCR test with these two primer pairs SCIDFW-SCIDRV and SMlDFW-SMlDRV was capable to detect the SCV and SMYEV diseases on in vitro strawberry plantlets. The infection rates of SCV and SMYEV on three strawberry cutivars were "My Da": 2.66% SCV and 3.3% SMYEV; "My Huong": 4% SCV and 2.66% SMYEV; "Phap": 4.6% SCV and 1.3% SMYEV. Vims-free strawberry plantlets were obtained, and were used as a vims-free expiant source for the strawberry propagation.

Micropropagation of rose (Rosa hybrida L. ‘Baby Love’) often encounter some abnormal phenomena such as yellow and abscission leaf, hyperhydricity, etc. These phenomena effect on the quality of shoots cultured in vitro as well as the survival rate of plantlets after transferred to greenhouse. This is due to the accumulation of ethylene in culture vessel, which leads to an increase in enzyme activity of cellulase and pectinase resulted in disrupting the cell wall binding and inducing organ abscission. In this study, the effect of silver nanoparticles (AgNPs) to overcome these abnormal phenomena as well as its effect on the growth and development of shoots and plantlets in rose cultured in vitro were evaluated. The results showed that after 6 weeks of shoot culture, the medium supplemented with 2 ppm AgNPs was the most suitable for in vitro shoot multiplication with the highest number of shoots/explant (6.67 shoots), shoot height (3.06 cm), fresh weight (451.00 mg), dry weight (58.33 mg), SPAD (32.28) and dry mass ratio(12.33%). Adding 3 ppm AgNPs into in vitro rooting medium may improve the growth and develop involve in plant height (3.06 cm), number of leaves (6.33), leaf length (1.50 cm), leaf width (1.50 cm), fresh weight (137.67 mg), dry weight (13.00 mg), number of roots (4.33), SPAD (39.37), dry mass ratio (9.40%) of rose plantlet after 4 weeks of culture. After treatment with AgNPs, the abnormal phenomena including ethylene gas accumulation (0.30 ppm), cellulase enzyme activity (0.14 UI/mL) and pectinase enzyme activity (0.40 UI/mL) was reduced compare with the other treatments and the control. In addition, the high survival rate (93.33%) of plantlets was also observed after 4 weeks transferred to greenhouse. On the other hand, the treatment with 5 ppm AgNPs also induced early rose in vitro flowering; however, when using AgNPs at high concentrations (7 ppm) inhibited growth, development, toxicity and even death of explants.

Maximal crop performance potential and land area suitable for cultivation are usually restricted by adverse environmental conditions. Among the abiotic factors, salinity stress is considered as one of the main threats, which causes ionic toxicity, dehydration and oxidative stresses on the plants. Alarmingly, the impact of salinity is predicted to be more severe in the forthcoming years due to global warming. Therefore, development of new cultivars with better salinity resistance with mimimized yield penalty under the adverse condition, either by breeding or genetic engineering approach, has attracted a great attention from the scientists. In this review, important parameters used in evaluation of plant resistance ability against salinity stress are discussed, which highlights the necessity to obtain multi-sets of biological data ranging from analyses of morphological alterations to physiological, biochemical and molecular responses, as well as by performing -omics studies to find out network of salinity-responsive pathways. Literature review also demonstrates that the relevance of salinity condition setup in terms of concentration and duration is required in experimental design. Furthermore, recent investigations on genome duplication, activities of non-coding sequence or epigenetics also reveal their regulatory roles in shaping plant response and tolerance degree toward salinity stress. Collection of such data not only contributes to widen scientific understanding of plant response mechanisms and adaptation to this stress factor but also facilitates the identification of important genes associating with plant tolerance to salinity. Therefore, the presented information could be used as a reference for the salinity stress-related studies serving for crop innovation and transgene function characterization.

MAS is the mordem breeding used commonly nowaday. MAS based on estimating exactly sites of genes on the map and the tightly relationships between the markers and the interested genes to estimate genotype of individuals in population. Molecular markers such as RAPD, AFLP, RFLP have been used for mapping but they cannot be directly used in breeding. These markers, they must be developped to STS markers so that they can be used for MAS. To apply MAS need a lots of easy and typical STS markers linked to genes confrolling interested fraits. Following the results on the QTLs mapping by AFLP markers for some root fraits related to drought resistance, we have developped STS markers from AFLP fragments for the use in MAS. We have cloned and sequenced six AFLP fragments linked to root number, root thickness, root length, root weight to shoot ratio and deep root weight to shoot ratio. From these sequences we designed six pairs of STS primers. We found out the PCR conditions for STSAVM62, STSAVM22, STSAVM87 primers with respective annealing temperature 54*'C, 53°C and 60*'C. However, the PCR products were not polymorphic. To create the polymorphism between lines, we attemped to use a single STS primer. As the results when amplified forward primer of STSAVM62, the polymorphic band of lOOObp was obtained. This band, proved to be stable in the population and inherited through progenies so it can be used in breeding of drought resistance rice lines.

Cá bông lau, tra bần và cá dứa là 3 loài cá kinh tế quan trọng trong giống Pangasius. Chúng có đặc điểm bên ngoài giống nhau nên dễ bị nhẫm lần ở giai đoạn cá nhỏ. Nghiên cứu này nhằm phân biệt 3 loài cá này dựa trên sự khác biệt về DNA mã vạch, gene COI (cytochrome c oxidase subunit I), và những đặc điểm hình thái. Cá được thu với nhiều kích cỡ khác nhau (>90 mẫu/loài) ở vùng hạ lưu sông Mekong. So sánh trình tự COI (15 mẫu, trong đó có 4 mẫu có trình tự riêng biệt với số truy cập ở Genbank từ KT289877 đến KT289880) cho thấy khoảng cách di truyền theo phương pháp “Kimura-2 parameter” giữa 3 loài tương đối lớn, dao động từ 9,33 – 12,10%. Về hình thái, các chỉ tiêu đếm gồm số lượng tia mềm của các vi và số lượng lược mang có khoảng biến động tương đương nhau giữa 3 loài nhưng các chỉ tiêu đo khác biệt có ý nghĩa (P<0,01). Kết quả phân tích thành phần chính dựa trên các chỉ tiêu đo cho thấy 3 loài tách thành nhóm riêng biệt. Điểm nhận dạng của cá dứa là thân hình dài, cuống đuôi dài, mắt to và răng lá mía dạng chữ nhật. Cá tra bần khác cá bông lau ở những đặc điểm của phần đầu. Số lượng thùy, hình dạng và kích thước bóng hơi cũng khác biệt giữa 3 loài. Mối quan hệ loài dựa trên kết quả di truyền và hình thái đều cho thấy bông lau gần với tra bần hơn cá dứa và giữa tra bần - cá dứa có sự khác biệt lớn nhất.

DNA barcoding is a tool for species discrimination and identification which helps overcome the problem of identification that cannot be covered by morphological identification. Quercus is the second biggest genus of Fagaceae in Vietnam as well as Lam Dong province after Lithocarpus. However, the species discrimination study of the Quercus species in Vietnam and Lam Dong province has yet to be well uncovered due to ambiguous species boundaries and the lack of universal molecular markers. In this study, the DNA barcodes were tested to discriminate among the species of the Quercus genus in Lam Dong province. A total of sixteen and two samples of the Quercus and Lithocarpus genus (out-group) were tested using matK, rbcL, and internal transcribed spacer (ITS). Of which, the new sequences in this study were sequenced from six species and one unknown species of Quercus, the rest was retrieved from GenBank. The BLAST, neighbor-joining, and Bayesian methods were employed to examine species discrimination success. The results showed that ITS was an efficient single-locus barcode for Quercus species by yielding the highest rate of universality as well as the best discriminatory and authentication power among the barcodes examined. In addition, the combination of ITS+matK+rbcL achieved the highest species discrimination. Therefore, matK and rbcL should not be used as DNA barcodes for the species identification of Quercus, whereas the combination of three genes that were proposed in this study is the most suitable DNA barcode for identifying Quercus species in Lam Dong province.