Expression, purification and evaluation of recombinant L-asparaginase inmehthylotrophic yeast Pichia pastoris: Expression, purification and evaluation of recombinant L-asparaginase in mehthylotrophic yeast Pichia pastoris: Research article

L-asparaginase (EC 3.5.1.1), a therapeutic enzyme used in the treatment of childhood acute lymphoblastic leukemia (ALL). Hence, the goal of this work is study the expression and evaluation of hydrolysis activity of native sequence (X12746) encoding for L-asparaginase from Erwinia chrysanthemi NCPBB1125 in the popular expression system Pichia pastoris. The sequence of asn encoded for mature protein was expressed in P. pastoris SMD1168 and X33. SDS-PAGE analysis showed recombinant L-asparaginase was secreted efficiently. Stable and high hydrolysis activity of extracellular L-asparaginase in P. pastoris SMD1168 making it a potential candidate to produce recombinant protein. After purification, a specific band whose appearance approximately 45 kDa indicating the glycosylated protein with specific activity by 6.251 Umg-1 and about 3 folds purifications.L-asparaginase (EC 3.5.1.1), một loại enzyme được sử dụng trong điều trị bệng ung thư bạch cầu mãn tính ở trẻ em. Mục tiêu của nghiên cứu này là biểu hiện và đánh giá hoạt tính thủy phân của L-asparaginase mã hóa bởi đoạn gene (X12746) tương ứng từ Erwinia chrysanthemi NCPBB1125 được biểu hiện trong nấm men Pichia pastoris. Gene đã được cắt signal peptide và biểu hiện trong P. pastoris SMD1168 and X33. Qua phân tích kết quả điện di SDS-PAGE của môi trường sau lên men, L-asparaginase tái tổ hợp được tìm thấy trong dịch ngoại bào của P. pastoris. Với khả năng sản xuất protein có hoạt tính cao hơn so với chủng P. pastoris X33, SMD1168 được lựa chọn để biểu hiện L-asparaginase tái tổ hợp. Sau khi tinh sạch, sự xuất hiện của một băng có kích khối lượng phân tử xấp xỉ 45 kDa trên điện di SDS-PAGE cho thấy protein tái tổ hợp đã bị glycosyl hóa với hoạt tính riêng 6.251 Umg-1 và đạt độ sạch 3.471 lần

ENGLISH-MAJORED STUDENTS’ LISTENING DIFFICULTIES AND USE OF STRATEGIES AT MIEN DONG UNIVERSITY OF TECHNOLOGY, VIETNAM

Through the years, difficulties in English listening and listening strategies have been conducted by many researchers. Most of studies have pointed out the common difficulties and strategies which students often have. Focusing on the same subject with a new perspective, this research aimed at understanding English majors’ difficulties in listening and use of listening strategies. A total of ninety eight freshmen English-majored students at Mien Dong University took part in answering the questionnaire and five students answered the semi-structure interview questions. The data gained from the questionnaire were analyzed by SPSS version 20.0 in terms of descriptive statistic. The findings revealed that English-majored students had many difficulties in listening such as the difficulties related to the listener, the content of the dialogue, the speaker, the physical setting and the linguistic factors. In terms of listening strategies, the finding showed that the cognitive listening strategies were used more frequently than metacognitive and socio-affective strategies. Based on the findings, some implications were made to contribute to the administrations, teachers and students at Mien Dong University of Technology.  Article visualizations

Strengthen roles of commercial banks in vietnam economy– a case of eximbank

Is it the time for us to evaluate roles of Vietnam commercial banks and importance of risk management activities? This paper uses both quantitative analysis with statistical data and charts, combined with qualitative analysis including synthesis, inductive and explanatory methods in order to estimate and compare market risk via beta CAPM of Eximbank (EIB) and Asia Commercial Bank (ACB), 2 big listed joint stock banks in Vietnam. Research findings show us that market risk of Eximbank is higher and increase during post-low (L) inflation stage, compared to pre-L inflation time. Results may be used for policy implications and research models can be references for other countries including emerging markets

IDENTIFICATION AND CHARACTERIZATION OF A PURPLE NONSULFUR BACTERIUM ISOLATED FROM COASTAL AREA OF HAI PHONG FOR USING IN PRODUCTION OF UNSATURATED FATTY ACID (OMEGA 6, 7, 9)

Purple nonsulfur bacteria are a group that has so much biotechnological applications, particularly in producing of functional food rich with unsaturated fatty acids. A purple nonsulfur bacterium (named HPB.6) was chosen based on its strong growth, high lipid and synthesis of unsaturated fatty acid (omega 6,7,9). Studying on basic biological characteristics showed that the cells of HPB.6 were observed as ovoid-rod shape, none motility, Gram negative staining. The diameter of single bacterium was about 0.8-1.0 µm. The cells divide by binary fission and had bacteriochlorophyll a (Bchl a). This bacterium grew well on medium with carbon and nitrogen sources such as acetate, succinate, pyruvate, butyrate, glutamate, arginine, leucine, tyrosine, alanine, methionine, threonine, glutamine, yeast extract and NH4Cl. This selected strain grew well on medium with salt concentrations from 1.5 - 6.0% (optimum 3%), pH from 5.0 to 8.0 (optimum at pH 6.5) and could withstand Na2S at 4.0 - 5.2 mM. Based on morphological, physiological properties and 16S rRNA analysis received demonstrated that HPB.6 strain belongs to the species Rhodovulum sulfidophilum

THE IMPLEMENTATION OF COMMUNICATIVE LANGUAGE TEACHING IN THE CONTEXT OF ONLINE LEARNING: A LITERATURE REVIEW

With the occurrence of the COVID-19 crisis, there has been dramatically growth and adoption of online education. As a consequence of the epidemic, institutes have been compulsory to close, and teaching and learning have changed fully to home studying. As a result, numerous educational institutions have adopted online teaching and learning on a massive scale. To combine the Communicative Language Teaching (CLT) approach with a framework of computer-assisted language learning seems to be the best strategy during a coronavirus outbreak. This study offers a survey of the literature on Communicative Language Teaching in the situation of online teaching and studying. This paper begins with an overview, definition, and characteristics of CLT. It then examines how CLT can be beneficial in a virtual classroom: advantages and disadvantages. Besides, it discusses the approaches to using CLT in online teaching and learning. This paper's goal is to provide an effective overview that can be used for online language instruction. The study will add to our understanding of Communicative Language Teaching and its use in an online setting.  Article visualizations

Influences of Dynamic Moving Forces on the Functionally Graded Porous-Nonuniform Beams

The dynamic response of functionally graded (FG) porous-nonuniform beams subjected to moving forces is investigated. The beam cross-section is assumed to vary longitudinally in the width direction by a linear or quadratic function. A modified rule of mixture, taking the effect of porosities into account, is adopted in evaluating the effective material properties. Based on Timoshenko beam theory, governing equations of motion are derived from Hamilton's principle, and they are solved by a finite element model. The dynamic response of a simply supported FG porous beam is computed with the aid of the Newmark method. The validation of the derived formulation is confirmed by comparing the obtained numerical results with the data available in the literature. A parametric study is conducted to highlight the effect of the material inhomogeneity, porosity volume fraction, section profile and loading parameters on the dynamic behavior of the beams

COMPARATIVE STUDY ON VOLATILE COMPOUNDS OF AGARWOOD FROM KHANH HOA PROVINCE EXTRACTED BY DIFFERENT METHODS

Agarwood from Aquilaria crassna cultivated in Khanh Hoa province was extracted by 5 methods, including simple, enzyme-assited, and microwave-assisted hydrodistillation, extraction with solvent and supercritical carbon dioxide. The volatile compounds of the products were analyzed by GC-MS. Almost all samples contain some common characteristic components, such as Valerianol, Agarospirol, Eudesmol b-, Eudesmol 10-epi-g-, 2-Allyl-4-methylphenol, Guaiol and Neopetasone. However, there were obvious differences in yields, composition, and number of identified components. The application of the more advanced methods for the extraction of agarwood resulted in saving of time and energy, and some improvement of product yield. However, these methods also lead to unconventional products with many unknown components, what requires further investigations

ĐẶC ĐIỂM TƯỚNG ĐÁ - CỔ ĐỊA LÝ PLEISTOCEN MUỘN-HOLOCEN KHU VỰC CỬA SÔNG BA LẠT

Lithofacies and paleogeographical characteristics of late Pleistocene-Holocene deposits are related to three sedimentary system tracts: Lowstand systems tract (LST) corresponds to the low regressive phase from 50 ka BP to 18 ka BP. The sedimentary accumulative space is situated from the boundary of weathering crust to the 100 m water depth. In Ba Lat rivermouth area, the lowstand systems tract is dominated by the alluvial silty sand facies group (arLST); Transgressive systems tract (TST) in Ba Lat rivermouth area constitutes a lithofacies section including three facies in upward direction as follows: (1) Transgressive alluvial silty - sand facies (atTST). (2) Transgressive estuary sandy - mud facies (amtTST). (3) Lagoonal maximum transgressive greenish clay facies (mtTST); Highstand systems tract (HST) in the downstream Red river delta area constitutes a deltaic plain structure consisting of three parts: High subaerial delta, low subaerial delta and subaqueous delta, which had been formed from 5 ka BP.Đặc điểm tuớng đá - cổ địa lý trầm tích Pleistocen muộn-Holocen khu vực cửa sông Ba Lạt gắn liền với ba miền hệ thống trầm tích: Miền hệ thống trầm tích biển thấp (LST) tương ứng với pha biển thoái thấp từ 50.000 năm BP đến 18.000 năm cách ngày nay. Không gian tích tụ của miền hệ thống này được giới hạn từ ranh giới miền xâm thực (vỏ phong hóa) đến độ sâu 100 m nước. Trong khu vực cửa Ba Lạt nhóm tướng aluvi biển thoái thống trị (arLST); Miền hệ thống trầm tích biển tiến (TST) trong khu vực cửa sông Ba Lạt cấu thành một mặt cắt gồm ba tướng từ dưới lên: (1) tướng cát bột aluvi biển tiến (atTST), (2) tướng bùn cát cửa sông biển tiến (amtTST) và (3) tướng sét xám xanh vũng vịnh biển tiến cực đại (mtTST); Miền hệ thống trầm tích biển cao (HST) trong khu vực hạ lưu châu thổ sông Hồng tạo nên một cấu trúc đồng bằng châu thổ bao gồm: Đồng bằng châu thổ cao, Đồng bằng châu thổ thấp và châu thổ ngập nước có tuổi từ 5.000 năm BP

Tannins: Extraction from Plants

The chapter presents mainly on different extraction methods of tannin. Some technical means required for effective extraction are also presented, for example, collection and treatment of plant and drying and storage of plant. Opportunity and challenges in application of extraction methods are also exhibited in the chapter