Transformation of glycosyltransferase dnrs and auxiliary DNRQ genes into the Streptomyces peucetius MH9.2 for the enhance of doxorubicin production

Doxorubicin antibiotic produced by Streptomyces peucetius is a very crucial antibiotic with a large spectrum used as an anticancer drug and in clinical treatment. Production of doxorubicin from wild type strain by microbiological fermentation process is nomally very low yield and limited. The enhancement of doxorubicin production (DXR) by the genetically engineering of the auxiliary genes involved in the pathway of doxorubicin biosynthesis from Streptomyces peucetius has being focused by many research groups. The gene cluster responsible for biosynthesis of doxorubicin had been isolated, sequenced and characterized. Among them, the dnrQ and dnrS genes belong to the gene cluster encoded for the glycosyltransferase and helper enzymes, which are responsible for attachment of sugar moiety to -rhodomycinon intermediate and regulation of doxorubicin production, respectively. In this research, the dnrQ and dnrS genes were isolated and cloned in the p25.1 vector containing the strong promoter (ermE*) to generate the p25.1QS as a recombinant vector. The obtained plasmid was transferred into the host strain Streptomyces peucetius MH9.2 by the protoplast transformation method to generate the S. peucetius MH9.2SQ strain. Doxorubicin production from the recombinant S. peucetius MH9.2SQ and the parent strain were extracted and purified by using chlorofrom and methanol solvents. The products were confirmed by HPLC, LC-mass analysis and antibacterial bioassay. The results showed that the over production of doxorubicin was accumulated by the recombinant strain from the fermentation broth. In the S. peucetius MH9.2SQ, the doxorubicin productivity was 3.1 to 3.6 folds higher than in the parent strain. This recombinant strain could be a potential candidate for further research in enhancement and larger biomass scale of DXR production

PURIFICATION OF RAVE COMPLEX FROM Saccharomyces cerevisiae USING FLAG TAG-AFFINITY PURIFICATION METHOD

RAVE (Regulator of the H+-ATPase of the Vacuolar and Endosomal membranes) is an            essential factor of assembly and reversible disassembly of V-ATPase. RAVE complex has three subunits, which are Rav1p, Rav2p and Skp1p. There are few studies on RAVE so it is very             important to study structure of RAVE complex to understand more about the regulation of the assembly and reassembly at V-ATPase. In this study the RAVE complex was purified by affinity purification by fussing FLAG tag to subunit Rav1p or Rav2p. Experimental process: yeast cells were incubated in 8 L YEPD medium at 30 oC, 200 rpm (OD600nm around of 3). Furthermore                   harvested cells were broken by a French pressure cell disruptor at 25,000 p.s.i in TBSE (50 mM Tris/Cl, 150 mM NaCl, 1 mM EDTA, pH 7.4) with 1 mm PMSF. The cell lysate was centrifuged at 20,000 xg for 20 minutes at 4 oC. Then, the supernatant, was achieved by centrifugation, and loaded onto a small column contained 1 ml of anti-FLAG M2 gel. After washing anti-FLAG column with TBSE, RAVE complex was eluted with TBSE containing 100 µg/ml FLAG               peptides. The results showed RAVE complex purification from strain with FLAG tag fused in                 C-terminus of Rav2 is better than RAVE complex purification from the yeast strain S. cerevisiae with FLAG tag fused in N-terminus of Rav1 or C-terminus of Rav1

Comparative study on vision based rice seed varieties identification

Abstract-This paper presents a system for automated classification of rice variety for rice seed production using computer vision and image processing techniques. Rice seeds of different varieties are visually very similar in color, shape and texture that make the classification of rice seed varieties at high accuracy challenging. We investigated various feature extraction techniques for efficient rice seed image representation. We analyzed the performance of powerful classifiers on the extracted features for finding the robust one. Images of six different rice seed varieties in northern Vietnam were acquired and analyzed. Our experiments have demonstrated that the average accuracy of our classification system can reach 90.54% using Random Forest method with a simple feature extraction technique. This result can be used for developing a computer-aided machine vision system for automated assessment of rice seeds purity

A Multicentre Molecular Analysis of Hepatitis B and Blood-Borne Virus Coinfections in Viet Nam

Hepatitis B (HBV) infection is endemic in Viet Nam, with up to 8.4 million individuals estimated to be chronically infected. We describe results of a large, multicentre seroepidemiological and molecular study of the prevalence of HBV infection and blood-borne viral coinfections in Viet Nam. Individuals with varying risk factors for infection (n = 8654) were recruited from five centres; Ha Noi, Hai Phong, Da Nang, Khanh Hoa and Can Tho. A mean prevalence rate of 10.7% was observed and levels of HBsAg were significantly higher in injecting drug users (IDUs) (17.4%, n = 174/1000) and dialysis patients (14.3%, n = 82/575) than in lower-risk groups (9.4%; p<0.001). Coinfection with HIV was seen in 28% of HBV-infected IDUs (n = 49/174) and 15.2% of commercial sex workers (CSWs; n = 15/99). HCV infection was present in 89.8% of the HBV-HIV coinfected IDUs (n = 44/49) and 40% of HBV-HIV coinfected CSWs (n = 16/40). Anti-HDV was detected in 10.7% (n = 34/318) of HBsAg positive individuals. Phylogenetic analysis of HBV S gene (n = 187) showed a predominance of genotype B4 (82.6%); genotypes C1 (14.6%), B2 (2.7%) and C5 (0.5%) were also identified. The precore mutation G1896A was identified in 35% of all specimens, and was more frequently observed in genotype B (41%) than genotype C (3%; p<0.0001). In the immunodominant ‘a’ region of the surface gene, point mutations were identified in 31% (n = 58/187) of sequences, and 2.2% (n = 4/187) and 5.3% (n = 10/187) specimens contained the major vaccine escape mutations G145A/R and P120L/Q/S/T, respectively. 368 HBsAg positive individuals were genotyped for the IL28B SNP rs12979860 and no significant association between the IL28B SNP and clearance of HBsAg, HBV viral load or HBeAg was observed. This study confirms the high prevalence of HBV infection in Viet Nam and also highlights the significant levels of blood-borne virus coinfections, which have important implications for hepatitis-related morbidity and development of effective management strategies

SOME TERPENE COMPOUNDS ISOLATED FROM CALLICARPA MACROPHYLLA (L.) SPECIES IN VIETNAM

Callicarpa macrophylla L. (Tu Chau la to) usually used in Vietnam traditional medicine for gastrointestinal bleeding, nosebleeds, in addition, it is also used for treating osteoarthritis pain. Phytochemical investigation of the n-hexan and ethyl acetate extract of Callicarpa macrophylla L. led to the isolation of β-sitosterol (1), β-sitosterol-3-O-β-D-glucopyranoside (2), stigmasta-7,22-dien-3β-ol (3), β-amyrin (4), ent-1α-acetoxy-7β,14α-dihydroxy-kaur-16-en-15-on (5) và ent-7β,16,17,18-tetrahydroxy-kaur-16-en-15-on (6). Their chemical structures were determined by spectroscopic methods including MS, 1D, 2D NMR and comparing with those reported in previous papers. Three compounds 4, 5, 6 were isolated for the first time from Callicarpa macrophylla  plant

Making sense of Vietnamese consumers in the casual wear market

With Focus Groups Interviews as the main research approach, this project aims at providing a comprehensive understanding of Vietnamese consumers in the casual wear market. From this understanding, marketing implications and recommendations are discussed further

The Role of p.Ser1105Ser (in <i>NPHS1</i> Gene) and p.Arg548Leu (in <i>PLCE1</i> Gene) with Disease Status of Vietnamese Patients with Congenital Nephrotic Syndrome: Benign or Pathogenic?

Background and Objectives: Congenital nephrotic syndrome (CNS), a genetic disease caused by mutations in genes on autosomes, usually occurs in the first three months after birth. A number of genetic mutations in genes, which encode for the components of the glomerular filtration barrier have been identified. We investigated mutations in NPHS1, NPHS2, PLCE1 (NPHS3), and WT1 genes that relate to the disease in Vietnamese patients. Materials and Methods: We performed genetic analysis of two unrelated patients, who were diagnosed with CNS in the Vietnam National Children&#8217;s Hospital with different disease status. The entire coding region and adjacent splice sites of these genes were amplified and sequenced using the Sanger method. The sequencing data were analyzed and compared with the NPHS1, NPHS2, PLCE1, and WT1 gene sequences published in Ensembl (ENSG00000161270, ENSG00000116218, ENSG00000138193, and ENSG00000184937, respectively) using BioEdit software to detect mutations. Results: We detected a new variant p.Ser607Arg and two other (p.Glu117Lys and p.Ser1105Ser) in the NPHS1 gene, as well as two variants (p.Arg548Leu, p.Pro1575Arg) in the PLCE1 gene. No mutations were detected in the NPHS2 and WT1 genes. Patient 1, who presented a heterozygous genotype of p.Ser1105Ser and p.Arg548Leu had a mild disease status but patient 2, who presented a homozygous genotype of these alleles, had a severe phenotype. Conclusions: These results suggest that variants p.Ser1105Ser (in NPHS1 gene) and p.Arg548Leu (in PLCE1 gene) in the homozygous form might play a role in the development of the disease in patients

Optimization of Microwave-Assisted Extraction Process of Callicarpa candicans (Burm. f.) Hochr Essential Oil and Its Inhibitory Properties against Some Bacteria and Cancer Cell Lines

Callicarpa candicans (Burm. f.) Hochr. (Callicarpa cana L.) is a medicinal plant that is distributed mainly in the tropics and subtropics of Asia and finds a wide range of uses in traditional medicine. In this study, we attempted and optimized the microwave-assisted hydro-distillation (MAHD) process to obtain essential oil from the leaves of C. candicans. In addition, the obtained oil was analyzed for volatile composition by gas chromatography&ndash;mass spectrometry (GC-MS) and assayed for bioactivity against several bacteria and cancer cell lines. To optimize the extraction process, response surface methodology (RSM) in combination with central composite design (CCD) was adopted. Experimental design and optimization were carried out with respect to three experimental factors including the ratio of water to raw material, extraction time, and microwave power. The optimal extraction conditions were obtained as follows: water to raw material ratio of 6/1 (v/w), extraction time 42 min, and microwave power 440 W. Composition determination of the obtained C. candicans essential oil indicated the presence of predominant components including caryophyllene &lt;b-&gt; (10.45%), cadinene &lt;d-&gt; (10.28%), gurjunene &lt;a-&gt; (8.95%), muurolene &lt;g-&gt; (8.92%), selinene &lt;a-&gt; (7.06%), selinene &lt;b-&gt; (5.59%), and copaene &lt;a-&gt; (5.40%). In comparison with the essential oils obtained via traditional hydro-distillation method, the essential oil extracted by MAHD exhibited superior anti-proliferative activity on all tested cancer cell lines. Current results imply that the MAHD is capable of recovering biologically-active natural products of greater quantity than that recovered by the conventional distillation

Hepatitis C virus in Vietnam: high prevalence of infection in dialysis and multi-transfused patients involving diverse and novel virus variants.

Hepatitis C virus (HCV) is a genetically diverse pathogen infecting approximately 2-3% of the world's population. Herein, we describe results of a large, multicentre serological and molecular epidemiological study cataloguing the prevalence and genetic diversity of HCV in five regions of Vietnam; Ha Noi, Hai Phong, Da Nang, Khanh Hoa and Can Tho. Individuals (n=8654) with varying risk factors for infection were analysed for the presence of HCV Ab/Ag and, in a subset of positive specimens, for HCV RNA levels (n=475) and genotype (n=282). In lower risk individuals, including voluntary blood donors, military recruits and pregnant women, the prevalence of infection was 0.5% (n=26/5250). Prevalence rates were significantly higher (p<0.001) in intravenous drug users (IDUs; 55.6%, n=556/1000), dialysis patients (26.6%, n=153/575) commercial sex workers (CSWs; 8.7%, n=87/1000), and recipients of multiple blood transfusions (6.0%, n=32/529). The prevalence of HCV in dialysis patients varied but remained high in all regions (11-43%) and was associated with the receipt of blood transfusions [OR: 2.08 (1.85-2.34), p=0.001], time from first transfusion [OR: 1.07 (1.01-1.13), p=0.023], duration of dialysis [OR: 1.31 (1.19-1.43), p<0.001] and male gender [OR: 1.60 (1.06-2.41), p=0.026]. Phylogenetic analysis revealed high genetic diversity, particularly amongst dialysis and multi-transfused patients, identifying subtypes 1a (33%), 1b (27%), 2a (0.4%), 3a (0.7%), 3b (1.1%), 6a (18.8%), 6e (6.0%), 6h (4.6%), 6l (6.4%) and 2 clusters of novel genotype 6 variants (2.1%). HCV genotype 1 predominated in Vietnam (60%, n=169/282) but the proportion of infections attributable to genotype 1 varied between regions and risk groups and, in the Southern part of Vietnam, genotype 6 viruses dominated in dialysis and multi-transfused patients (73.9%). This study confirms a high prevalence of HCV infection in Vietnamese IDUs and, notably, reveals high levels of HCV infection associated with dialysis and blood transfusion