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Azurin, a small molecular weight protein produced by Pseudomonas aeruginosa and several gram-negative bacteria has received considerable attention because of its potential anti-parasitic, anti-viral and anti-cancer activity. In this study, 437 bp-gene of azurin was amplified and cloned from Pseudomonas aeruginosa VTCC-B-657. This gene was then inserted into the PET22b+ vector and the recombinant plasmid was introduced into Escherichia coli BL21(DE3) by chemical methods. The recombinant strain was checked by polymerase chain reaction method and sequencing analysis. Next, the recombinant azurin (r-Azu) was expressed and purified by Ni2+-ProBondTM resin column. The molecular mass of purified r-Azu was 16 kDa when determined by SDS-PAGE and was 13.88 kDa when determined by LC/MS. Interestingly, the purified r-Azu showed cytostatic activity only on breast cancer cell lines (MCF-7 and MDA with IC50 of 25.4 and 29.25 μg/ml respectively) but not on normal cells. These results suggest that r-Azu would be a potential candidate for anticancer drugs and deserves further study.

In the pentose phosphate pathway, glucose-6-phosphate dehydrogenase is an enzyme that helps red blood cells patients survive when they come into contact with oxidizing substances like oxygen, chemicals, or drugs. Glucose-6-phosphate dehydrogenase deficiency is an X-linked recessive genetic disorder brought on by gene mutations. The paper employs the formazan method to examine the prevalence of glucose -6-phosphate dehydrogenase deficiency in persimmons and its demand among different ethnic groups in the North of Vietnam.

In this study, the consortium of filamentous fungi affecting the metal protection of 04 types of grease (GOI/VN grease, salt-tolerant grease AMC-3/VN, PVK/VN grease, Russian PVK grease) was identified. Six steel-covering grease types exhibiting protection against fungal infections were taken for fungal isolation. Seven strains of filamentous fungi were isolated, characterized by colony morphology, analysis of ITS1-5,8S-ITS2 sequences, and abilities to produce extracellular enzymes (protease, amylase, cellulase, lipase). Besides, the influence of filamentous fungi on metal protection was evaluated by measurement of rust portfolio on metal surface after degreasing by using images ImageJ v.1.51 software. Among isolated strains, 07 isolates of filamentous fungi showing varieties in morphological colonies were selected and taxonomically identified as Penicillium chermesinum, Penicillium cuddlyae with over 98% similarity of ITS1-5,8S-ITS2 sequences compared with related ones deposited on GenBank (NCBI). Of those, 02 strains (M1.1 and M4.1) were capable of producing 4 types of extracellular enzymes. When utilizing Image J software to examine the effects of fungal isolates on the protective capabilities of grease covering materials against metal corrosion, rust spots with variable densities between 1.30%-18.66% appearing on the surface of CT5 steel were found to be formed by fungal attacks. The findings in present study therefore provide a fundamental basis for the effects of fungal growth on grease decomposition at the Hoa Lac Thach That/ Ha Noi testing area and further studies on damages caused by fungi to steel-covering greases as well as corrosion of the metal surface.

Prodigiosin (Pg), a secondary metabolism produced by numerous bacterial species, is known as anticancer, antibacterial, antifungal, immunosuppressant, antioxidant, antimalarial properties. Pg has been tested for antitumor activity in many different cancer cell lines but studies in LU-1, KB cell lines, and tumor-bearing mice are still limited. In this study, Serratia marcescens QBN VTCC 910026 strain (GenBank: KX674054.1) was mutated using Ethyl Methanesulfonate (EMS) to increase the production of Pg. One strain known as EMS 5 was capable of increasing prodigiosin biosynthetic yield by 52% when compared to the wild-type strain. Red bacterial pigmented colonies containing Pg were collected from solid media, lysed with acetone, purified with toluene: ethyl acetate at a ratio of 9: 1 (v/v), and then used to evaluate the potential anticancer activity. The purity of Pg was confirmed using a high-performance liquid chromatography (HPLC) method which indicated a 98% rate. Pg chemical formula which was determined using 1H-NMR and 13C-NMR spectroscopy, confirmed as prodigiosin (Pg). Human breast cancer cell lines MCF-7, oropharyngeal cancer KB, and particularly lung cancer LU-1 in vitro were used to test the anticancer activity of purified Pg compound. It showed a strong inhibitory ability in all the cancer cell lines. Furthermore, the isolated Pg had capable of inhibiting tumor growth, the tumor volume decreased by 36.82%, after 28 days. The results indicated that the bacterial prodigiosin from variants Serratia marcescens QBN VTCC 910026 strain is an encouraging fragment suitable for therapeutic applications.

Prodigiosin (Pg), a secondary metabolism produced by numerous bacterial species, is known as anticancer, antibacterial, antifungal, immunosuppressant, antioxidant, antimalarial properties. Pg has been tested for antitumor activity in many different cancer cell lines but studies in LU-1, KB cell lines, and tumor-bearing mice are still limited. In this study

The denaturing gradient gel electrophoresis (DGGE) is an effective culture-independent technique for assessing diversity of microbial communities. In this study, the PCR-DGGE technique was applied for analyzing the diversity of bacterial communities in marine sediment in the Truong Sa archipelago (Spratly Islands), Vietnam, and a comparison with cultivable bacterial fraction was performed. Three sediment samples taken from different depths were used in the study. A total of 17 bacterial strains were isolated and divided into 6 groups based on their colony and cell morphologies. Comparative analyses of nearly full-length 16S rDNA sequences retrieved from six representative strains of these morphologically distinguished groups indicated that they were most closely related to Bacillus amyloliquefaciens, Bacillus filamentosus, Bacillus endophyticus, Bacillus licheniformis, Pseudomonas balearica, and Raoultella ornithinolytica. The PCR-DGGE analyses carried out with the three sediment samples showed relatively diverse bacterial communities with 9 distinct bands, 6 of which were related to the isolated representatives, whereas the other three were identified as Vibrio proteolyticus, Priestia filamentosa, and Clostridium halophilum. Thus, by applying the PCR-DGGE technique, more thorough information on bacterial communities in the sediment of Truong Sa archipelago could be elucidated, providing useful information for further studies on the conservation and utilization of microbial resources in this ecosystem.

Compost is a highly humified organic fertilizer, rich in nutrients and a source of a variety of aerobic microorganisms, including actinomycetes, which develop in response to different levels of temperature, humidity, oxygen and pH. Microbes growing on the compost are believed to have the ability to produce extracellular hydrolytic enzymes. The purpose of this study was to determine the ability of thermophilic actinomycetes XM21 isolated from compost in producing hydrolytic enzymes, namely cellulase, amylase, protease, and lipase. The confirmation tests of hydrolytic enzymes-producing ability were conducted by inoculating the microbes into media containing cellulose, starch, gelatin and tween 80, using the method of disc diffusion. The results showed that strain XM21 capable of extracellular enzymes producing, such as cellulase, protease, amylase, lipase. Strain XM21 can grow well with high cellulase activity in a wide range of temperature between 30-55oC, optimum at 45oC. The strain can grow well on different media, utilized carbon sources with pH 5-10, and salinity of 0-5%. On the agar plate, the strain has white aerial mycelia, the mature spore chains appeared spirals, moderately long, bearing 10 to 35 spores each. Based on the biological characteristics and phylogenetic analysis of 16S rDNA, it can be concluded that strain XM21 is close to Streptomyces flavovariabilis (98, 12%), hence identified as Streptomyces flavovariabilis XM21.

Background: Cellulytic enzymes including carboxymethyl cellulases play the key role in hydrolysis of cellulose, a huge organic carbon reservoir on earth, into monomeric sugars and their eventual conversion into valuable chemicals and energy sources. Objectives: In this study, we described the identification of a basidiomycete isolate NDVN01 and optimization of culture conditions and medium components for CMCase production by this strain under liquid state fermentation. The CMCase was estimated as 32 - 33 kDa on a native Polyacrylamide gel electrophoresis (PAGE). Materials and Methods: We used 5 basidiomycetes for screening CMCase production, internal transcribed spacer (ITS) sequence analysis in combination with morphology for strain identification, and liquid state fermentation for optimization of CMCase production. Results: The maximum CMCase production by Peniophora sp. NDVN01 was obtained at 28°C, with the initial medium pH of 7 and within 120 hours of cultivation in the optimum medium containing 80% (v/v) of potato infusion, 0.6% (w/v) straw rice as additional carbon source and 0.2% (w/v) ammonium hydrogen phosphate as an additional nitrogen source, and 0.5% (w/v) pulp as inducer. Conclusions: Under optimal conditions, Peniophora sp. NDVN01 produced 24.65 ± 0.37 units of CMCase per mL of culture supernatant, which was 8.6 times higher than the amount (2.87 ± 0.28 U.mL -1) before optimization.

A gene coding for an endo-β-1,4-xylanase (XlnA) (glycosyl hydrolase family 10) from Aspergillus niger DSM 1957 was cloned and sequenced. The cDNA sequence (984 bp) and its putative endoxylanase (327 aa protein with a predicted molecular mass of 35.5 kDa and pI 6.23) showed 91.3–99.5% and 96.3–99.1% identities with cDNA sequences and their corresponding endoxylanases from A. niger strains from GenBank, respectively. The cDNA was expressed in Pichia pastoris GS115 under the control of AOX1 promoter at a level of 46.4 U/ml culture supernatant, after 144 h of growth at 30 °C in YP medium induced with 0.5% (v/v) of methanol. The molecular mass of the purified XlnA determined by SDS–PAGE was 35.5 kDa with a specific activity of 808.5 U/mg towards 1% (w/v) of birch wood xylan. Temperature and pH optimum were observed at 50 °C and pH 7.0, respectively. The enzyme was stable over a temperature range of 25–40 °C and at pH range of 4.5–8.5 and resistant to Tween 80 and acetone. The K m and V max value obtained for the purified xylanase were 25.5 mg/ml and 5000 μmol/min/mg protein with birch wood xylan as substrate, respectively. The xylanase was free of cellulase and mannanase activity but highly active towards birch wood xylan. The major products of the birch wood xylan hydrolysis were predicted as xylotriose, xylotetraose, and xylopentose. The biochemical characteristics suggested that the recombinant xylanase has a potential application, including use as a feed enzyme.

A novel extracellular endoglucanase from a basidiomycete strain Peniophora sp. NDVN01 was purified 2.8-fold to homogeneity through ammonium sulfate precipitation and gel filtration with Bio-Gel P-100 and Sephadex G-75. The endoglucanase had a specific activity of 163.8 U/mg protein and a molecular mass of 32 kDa. Optimum temperature and pH were at 60 °C and 4.5, respectively. The enzyme was stable at up to 42 °C and in the pH range of 3.5-5.5 with a residual activity of over 80% for 24 h of treatment. Ni2+ activated but other metal ions showed no or slight inhibitory effect on the enzyme activity. The endoglucanase showed a high resistance to most tested detergents and organic solvents. The endoglucanase catalyzed the hydrolysis of barley b-glucan and carboxymethyl cellulose (CMC), but not toward xylan, locust bean gum, and Avicel, typical substrates for xylanase, mannanase and exoglucanase, respectively. The kinetic parameters Km, Vmax, Kcat, and Kcat/Km for barley b-glucan and carboxymethyl cellulose were 5.9 mg/mL, 9804 U/mg, 6.14 × 105 min-1, and 1.04 × 105 and 34.8 mg/mL, 1825 U/mg, 1.14 × 105 min-1, and 0.33 × 104, respectively. Hydrolysis of CMC liberated cellobiose, cellotriose, cellotetraose, and a detectable amount of glucose. These results suggest that the endoglucanase might potentially be used in enzymatic reactions and to investigate the efficacy of feed enzymes.

Seventeen bacterial strains were isolated from 9 marine mud samples from the inshore environments of the East Sea. Four bacterial strains showed an inhibition against all tested microorganisms Staphylococcus aureus ATCC10832, Escherichia coli JM109, and Fusarium oxysporum. 16S rRNA sequences of four bacterial strains were obtained by PCR using specific primers. PCR products were cloned into E. coli DH5a using pJET1.2 blunt vector. The recombinant plasmids were sequenced and the lengths of these 16S rRNA sequences were ~930bp. The 16S rRNA sequence from the four bacterial DB1.2, DB1.2.3, DB4.2 and DB5.2 strain showed a high identity of 97 to 99% with the 16S rRNA sequence from Photobacterium sp., Oceanisphaera sp., Shigella sp., Stenotrophomonas sp, respectively. Mười bảy chủng vi khuẩn đã được phân lập từ 9 mẫu bùn biển từ các vùng ven bờ biển Việt Nam. Bốn chủng vi khuẩn được ghi nhận có khả năng ức chế mạnh sự sinh trưởng và phát triển của các chủng vi khuẩn Staphylococcus aureus ATCC10832, Escherichia coli JM109, và thậm chí cả nấm Fusarium oxysporum. Trình tự gene 16S rRNA của bốn chủng vi khuẩn này đã được khuếch đại bằng PCR sử dụng cặp mồi đặc hiệu. Sản phẩm PCR được nối ghép vào vector pJET1.2 blunt sử dụng T4 ligase, hình thành plasmid tái tổ hợp và biến nạp vào E. coli DH5. Khuẩn lạc có plasmid mang phân đoạn DNA chèn được nuôi cấy và tách plasmid. Trình tự 16S rRNA từ 4 chủng DB1.2, DB1.2.3, DB4.2 and DB5.2 chỉ ra có sự tương đồng 97 ÷ 99% so với trình tự 16S rRNA tương ứng của các chủng vi sinh vật biển trên ngân hàng gene thế giới là Photobacterium sp., Oceanisphaera sp., Shigella sp., và Stenotrophomonas sp., Journal of Vietnamese Environment, Vol 3 No 2 (2012)

An acid-stable and organic solvent-tolerant extracellular xylanase was isolated and purified from Aspergillus awamori VTCC-F312 and its properties were investigated. The xylanase was purified by Sephadex G-100 gel filtration chromatography and DEAE-Sephadex A-50 ion exchange chromatography to homogeneity. The enzyme had a molecular mass of 32 kDa and a specific activity of 217 U/mg protein, with optimum temperature of 50-55 °C and optimum pH of 5. This enzyme was stable at up to 45 °C and no loss of enzyme activity was observed after incubation for 6 h at 40 °C. The xylanase was stable within the pH range of 4-8 with no loss of enzyme activity after incubation at 30 °C for 1-4 h, even the enzyme activity was found to increase by 60% after incubation at pH 4 for 4 h. The Km and Vmax values were 12.6 mg oat spelt xylan per ml and 1000 U/mg protein, respectively. Dithiothreitol, -mercaptoethanol, and EDTA were found to increase the xylanase activity by 19%, 46%, and 138%, respectively. Except for Fe 3+ , the presence of 5 mM tested metal ions increased the enzyme activity by 18-52%. The enzyme showed high resistance to organic solvents and retained 63-86% and 44-61% of its activity in the presence of tested organic solvents at 30% and 80% (v/v), respectively. Triton X-100 and Tween 80 activated the xylanase to 128% and 116% of its activity, whereas SDS at the concentration of 5% completely inhibited the enzyme. These results suggested that the xylanase from A. awamori VTCC-F312 could potentially be used as a feed additive for monogastric animals.