Search

Search Results

##search.searchResults.foundPlural##

Evaluation of the Useability of Morphological Indicators of Otoliths forIdentification ofsome Marine Fish Species

Vu Quyet Thanh, Tran Van Dat

Date Received: 10-05-2022 / Date Accepted: 27-09-2022
In the presentpaper, we evaluate the ability to identify some marine fish species based on the analysis of morphological otoliths. Thestudy collected 180 sagitta of 10 species, then photographed, measured the basic sizeindices (BSI), and calculated the shape indices (ShI) in program R. Data were analyzed by standard statistical methods: ANOVA, Discriminant function analysis(DFA), and Canonical Analysis. The results of the analysis confirmed the possibility of using measurements of otolith morphology for the purpose of species identification. DFA based on basic measurements BSI could identify threespecies with 100% accuracy (18/18); threespecies with high accuracy from 77% to 95%. Based on the ShI shape index, 02 species can be identified with 100% accuracy (18/18); 03 species achieved high accuracy from 77% to 95%. When combining the basic measurements of BSI and ShI by DFA, the overall accuracy of the species was increased by 81.11%. The number of species with 100% accurate identification was increased to 4 species; 04 species achieved a high classification level from 77% to 95%.Result of this study showed that combiningBSI and ShI gave higest accuracy.
Identificationof Oyster Mushroom (Pleurotusspp.) Strains in the South Vietnam based on Morphological Characteristics and ITS Sequencing

Pham Van Loc, Ngo Thuy Tram, Le Thanh Nhan, Pham Nguyen Duc Hoang, Nguyen Hoang Dung, Ho Bao Thuy Quyen

Date Received: 15-08-2023 / Date Accepted: 25-12-2023 / Date Published: 12-06-2025
Oyster mushrooms (Pleurotusspp.) are one of the most commonly cultivated mushrooms in the world. In Vietnam, Pleurotus mushrooms have been popularly grown, especially in the southern region. The classification of oyster mushrooms is important in conservation and development of genetic resources. One of the primary methods for accurate classification of oyster mushrooms is based on their macroscopic and microscopic characteristics. Besides, classification based on the analysis of consensus sequences was widely applied, with ITS being the most used sequence region in fungal genetics. The objective of this study was to identify 15 oyster mushroom strains collected from the southern region through a combination of morphological characteristic analysis and ITS sequencing. The results showed that 10 strains were identified as P. pulmonarius, while 5 other strains were identified as P. ostreatus. The identification results based on ITS sequences were compatible with the morphological identifications. Following the phylogenetic tree based on ITS sequences, 10 phoenix cultivars belonged to P. pulmonariusclade, supported by a bootstrap value of 88%. The oyster cultivars and blue oyster cultivar belonged to Pleurotus cf. floridanus(P. ostreatus species), supported by a bootstrap value of 80%. The results of this study increased the basic data for identification and conservation purposes.
DOI: https://doi.org/10.31817/tckhnnvn.2023.21.12.
Identification of Causative Agent of Lotus Blight Disease in Thua Thien Hue in 2022

Ha Viet Cuong, Tran Thi Thu Ha, Le Quy Thao, Huynh Thi Tam Thuy, Le Van Vinh

Date Received: 02-02-2023 / Date Accepted: 18-04-2023
Blight is a destructive disease of Lotus (Nelumbo nucifera) that has emerged in Thua Thien Hue province in recent years. The objective of this study was to identify the etiological agent responsible for the disease. The pathogenicity of microorganisms isolated from diseased Lotus plants was evaluated by inoculating healthy Lotus plants with these isolates. The pathogenic fungus was evaluated for its morphological characteristics on potato dextrose agar (PDA) medium and on pieces of pine needles. Molecular identification of the pathogenic fungus was performed based on the sequencing of three barcode genes, including Internal Transcribed Spacer (ITS), Translation Elongation Factor 1 gene (ef1), and beta-tubulin (tub2). Symptom evaluation of diseased Lotus plants in nature suggested that the pathogen primarily attacked the upper part of the plant. Eight morphologically distinct bacterial and seven fungal isolates were obtained from the typical diseased petioles. Artificial inoculation of all bacterial and fungal isolates on leaf veins and petioles of Lotus plants revealed that only one fungal isolate, designated as N1, was pathogenic to Lotus, producing symptoms resembling those of the diseased plants in the field. Morphological evaluation, including the characteristics of fungal mycelia on PDA medium and the characteristics of conidia, identified the N1 isolate as a member of the genus Lasiodiplodiaof the family Botryosphaeriaceae. Molecular identification identified the N1 isolate as Lasiodiplodia theobromae. To the best of our knowledge, this is the first report in the world and in Vietnam that identifies L. theobromaeas the causative agent of blight disease in Lotus plants.
Protocol for Indentification in Tra Catfish (Pangasianodon hypophthalmus) by Morphological Taxonomyand Molecular Genetics methods

Tran Thi Thuy Ha, Tran Nguyen Ai Hang, Nguyen Thi Huong, Nguyen Thi Thu Thuy

Date Received: 12-03-2015 / Date Accepted: 30-08-2017 / Date Published: 03-07-2025
The combination of morphological taxonomy and molecular genetics methods is required for effective and accurate identification of Tra catfish (Pangasianodon hypophthalmus). The identification based on morphological characteristics is possible to identify accuratelyPangasiidae species that simply relieson number of spines, pelvic fins, pectoral fins, etc. In addition, sequence analysis of cytochrome c oxidase I (COI) andcytochrome b (Cytb) genes along with specialized softwares provide significantly reliable results, which contribute information to confirm the morphological classification. In this study, idetification based on molecular genetics method revealed 99-100% similarity in nucleotide sequences of COI and Cytb genes between 30 fish samples collected in An Giang and Ben Tre provinces with Tra catfish Pangasianodon hypophthalmus species. Our finding confirms the superiority and necessity of combining two identifications methods, morphological taxonomy and molecular genetics methods.
DOI: https://doi.org/10.31817/tckhnnvn.2017.15.7.
Identification of Drought-tolerant Lines and Local Cultivars for Development Genetic Material and Rice Breeding for Rainfed Environment

Nguyen Thi Hao, Dam Van Hung, Pham My Linh, Vu Quoc Dai, Le Thi Hau, Dong Huy Gioi, Vu Van Liet

Date Received: 02-02-2013 / Date Accepted: 18-04-2013
Drought is a major constraint affecting rice production, especially in rainfed areas of mountainous regions of Vietnam. Development of drought tolerant varieties will improve rainfed rice production. Identification of drought-tolerance of the lines and local cultivars is useful for the development of genetic material and rice breeding for adaptation to rainfed environments. Forty two rice accessions were evaluated for germination and seedling characteristics by treatment of rice seed with KClO3. The plants were planted in PVC pipe to evaluate root length and root growth under well-watered and water-stressed environments. In addition, QTLs associated with root lengthen and root growth were analyzed using SSR markers. We have identified 11 accessiopns (lines and local cultivars) with drought tolerance. Three best drought tolerant accessions, 455 (Khau li on/Q5), 464 (Mua chua, Dien Bien) and 487 (Khẩu lếch, Bak Kan) are recommended for rice breeding program for rainfed environment.
Study on Identification and Culture Conditionfor Biosynthesis of Laccase by Trametes polyzona TĐ16

Nguyen Thi Hong Lien, Tran Thi Huong, Nguyen Van Hieu, Dang Thi Nhung, Phan Thi Hong Thao

Date Received: 18-08-2023 / Date Accepted: 26-12-2023
White-rot fungi are capble of degrading wood lignin by extracellular lignin modifying enzyme system, in which laccase plays an important role in ligninolysis and is widely used in some industries. This study was carried out with the objective of identifying the white rot fungus TD16 and selected suitable conditions for the biosynthesis of laccase to apply in the biopulping. The strain TD16 was studied for biological characteristics and sequence of the ITS - rDNA gene analyzed. The fruiting bodies have a scalloped shape and the edges are smooth. The upper surface of fruiting bodies is dark brown with concentric circular veins. The hymenium layer is white-brown and rough. On MEA medium, the colonies of TD16 fungal strain are fluffy, snow white, and evenly circular. The strain TD16 has a relatively fast growth rate and can produce extracellular enzymes. The strain TD16 was identified as Trametes polyzonaand named as Trametes polyzonaTD16. The optimal culture conditions for enhanced laccase biosynthesis were investigated. Trametes polyzonaTĐ16 showed the highest laccase activity of upto 8.135 U/ml on MT2 medium containing 0.0625mM CuSO4after 7 days of fermentation at 37ºC and pH of 5.0.
IDENTIFICATION OF NOVEL T CELL EPITOPE REPERTOIRE IN NSP1 AND GP3 OF THE PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS TYPE 2

Tran Thi Huong Giang, Phan Hong Dien, Dong Van Hieu, Wen Bin Chung

Date Received: 02-11-2015 / Date Accepted: 03-05-2016
Virus gây hội chứng rối loạn sinh sản và hô hấp ở lợn (PRRSV) đã trở thành một trong những căn bệnh chính ảnh hưởng lớn tới ngành chăn nuôi lợn trên thế giới. Một số vắc xin đã được sử dụng để phòng và làm giảm ảnh hưởng của PRRS, tuy nhiên căn bệnh vẫn tồn tại và gây ảnh hưởng tới các trang trại chăn nuôi lợn. Phát triển một loại vắc xin trên cơ sở những hiểu biết về cơ chế miễn dịch qua trung gian tế bào nhằm kiểm soát PRRS là việc làm cấp bách và cần thiến hiện nay. Trong nghiên cứu này, chúng tôi đã sử dụng kỹ thuật tin sinh học để xác định các nhóm kháng nguyên tế bào T dựa trên chủng PRRSV ATCC VR-2332 (U87392.3). 12 trình tự a xít amin được sàng lọc bằng kỹ thuật IFN-γ ELISpot trong đáp ứng với tế bào PBMCs. Kết quả đã xác định được 2 peptide gồm 1b3 (YQLASYASYI) và GP3 (SVYAWLAFLSFSY) là epitop tế bào T. Đây có thể là một thông tin có giá trị trong việc phát triển một loại vắc xin có hiệu quả phòng PRRSV.
Selection, Identification of Bacillus spp. Producing Protease, and Determination of Enzyme Thermostability

Nguyen Hoang Anh, Nguyen Van Giang

Date Received: 02-08-2017 / Date Accepted: 01-09-2017 / Date Published: 06-08-2025
In this study, 180 Bacillus strains isolated from Chilli sources, cow rumens, pig small intestine, fermented milk, dairy industry effluent, soil have been used to determine protease activity. The data indicated that there were totally 124 strains producing extracellular protease, in which proteases from NT1.8 and NT3.9.3 isolated from dairy industry effluent were highest activity 423U/l and 274.7U/l, respectively. The evalutation of thermal stability showed that protease produced by NT 1.8 remained 80% after 2 hours incubation of enzyme at 50oC and remained 78% after enzyme incubation at 55oC for 30 min. Meanwhile, the activity of protease from strain NT 3.9.3 reduced dramatically after pre-treatment at 50 and 55oC. Strain NT1.8 was identified to be Bacillus amyloliquefaciens NT1.8 based on the comparison of sequence encoding for 16rRNA gene.
DOI: https://doi.org/10.31817/tckhnnvn.2017.15.8.
Results of Identification of Common Species in Genus Hieroglyphus (Orthoptera: Acrididae) in Hoa Binh Province in 2010-2011

Nguyen Hong Yen, Dinh Dai Quang, Nguyen Lan Huong, Nguyen Thi Lan Huong, Ho Thị Thu Giang, Nguyen Van Dinh

Date Received: 04-11-2011 / Date Accepted: 15-02-2012 / Date Published: 13-06-2025
This study aimed to clarify the scientific name of a common grasshopper species belonging to the Hieroglyphus Krauss (1873) genus, which causes serious damage to plantation in Hoa binh province since 1997. Fifty individuals of this species were reared singly at 250C ambient temperature condition for their morphologic characteristic observation and description. These characteristics were collated to those described in taxonomic system of Mistshenko (1952). Our study has confirmed that the species studied is H.tonkinensis Bolivar (1912). Our results of survey on the grasshopper species during 2010 and 2011 at 3 epidemic sites in Hoa Binh province at coordinates of 20053’34”N, 105014’56”E; 20045’53”N, 105015’49”E and 20041’39”N, 105013’44”E indicated that the most common grasshopper species in this province is H.tonkinensis Bolivar (1912). During survey periods this species occurs with high frequency of above 40% and may account for 87% of the population.
DOI: https://doi.org/10.31817/tckhnnvn.2012.10.1.
Morphological Characteristics and DNA Barcodesof Paris vietnamensis (Takht.) H.Li in Vietnam

Nguyen Tien Dung, Nguyen Quynh Nga, Tran Ngoc Lan, Nguyen Thi Thu, Ninh Thi Phip, Doan Thi Thanh Nhan, Le Thi Thu Hien, Nguyen Nhat Linh

Date Received: 15-11-2017 / Date Accepted: 17-06-2018
Plant identification is the basis for taxonomic classification and effective use of plant germplasm. In the present study, theplantspecies,Paris vietnamensis(Takht.) H.Li was characterized in terms of morphological characteristics. In addition, DNA barcodes based on ITS and psbA-trnH regions were analyzed. In comparison with other species of Parisgenus, P. vietnamensiswas characterized by several distinctive features such as: free portion of anther connective cylindrical; inner tepals longer than outer ones; ovary 4 - 7 deeply ribbed, horizontal cross section star-shaped, style inconspicuous,andseeds with red aril. DNA barcoding analyses provided support for the use of the ITS region as an efficient DNA marker for molecular identification of this species within ParisL. Genus.
Redefinition of Scientific Names of Genus and Species in Loach Genus Botia, (Cobitidae,Cypriniformes)in Vietnam

Nguyen Van Hao, Do Van Thinh, Nguyen Thi Hanh Tien, Nguyen Thi Dieu Phuong

Date Received: 06-03-2012 / Date Accepted: 25-07-2012 / Date Published: 13-06-2025
The classification of the species in genus Botia(Botinae, Cobitidae, Cypriniformes)currently have been changed. The genus BotiaGray, 1831, is separated into 4 genera: BotiaGray, 1831;SyncrossusBlyth, 1860;SinibotiaFang, 1936andYasuhikotakaNalbant 2002.In Vietnamrecorded 9 species of genus Botiawere recorded but no updated documentsconcerning the above-mentionedgenusclassification. Relying on thesescientific basesof the separation genus of Botia, established key identification genus, description characterisations genus of the loach, established key identification of species and description species of loach in Vietnam.The authors have definitedsciencetific name of loach inVietnam. Itshowed that only remaining 8 species but in 3 other genus. Genus YasuhikotakaNalbant, 2002 including 4 species and genus SyncrossusBlyth, 1860 including 2 species distributing in the Southern Vietnam and Highlands. Genus SinibotiaFang, 1936 have2 species distributing in highlands provinces of Northen Vietnam. This article providingupdate documents for convinience in research and and uniform scientific names of loach species.
DOI: https://doi.org/10.31817/tckhnnvn.2012.10.4.
Isolation and Identification of Bacteria Co-Cultivated with Non-Axenic Cultures of Chlorella

Vu Thi Hoan

Date Received: 06-02-2018 / Date Accepted: 06-09-2018
This study was investigated to find out the diversity of bacteria co-cultivatedwith microalgae Chlorella.Bacteria were isolated from two non-axenic algal cultures of Chlorella sp. strains C2 and C6 originated from soil using agar plates of 10- and 102-fold diluted nutrient broth.Based on the similarity of the almost full length 16S rRNA gene sequences, the type strains of species phylogenetically closely related to the isolated strains and neighbor-joining tree, the strains were identified at the genus level. Sixteen bacterial strains were isolated and identified as species of seven genera as follows: Caulobacter,Shinella,Aminobacter,Variovorax,Polaromonas,Brevundimonas,Emticicia. The study showed the diversity and abundance of bacteria co-cultivated with non-axenic cultures of algae.
Detection and Identification of Pinworm Syphacia obvelatain Experimental Mice

Nguyen Thi Hoang Yen, Nguyen Chi Hieu

Date Received: 13-12-2023 / Date Accepted: 23-05-2024 / Date Published: 12-06-2025
This study was conducted to identify the species of pinworms in experimental mice. Eggs of pinworms were examined from four white mice that were purchased from an animal facility before the conduct of experimental infection. The eggs were detected by the perianal tape test method, adult worms were collected by necropsy method, and then eggs and adult worms were identified based on their morphology. Besides, PCR and sequencing techniques were also applied to confirm the species identification. The results show that eggs were pointed oval (with one side flatted) in shape and approximately 129.2 x 39.17m in size. Adult worms were 3-5mm in length, having two subtle cervical alea, a bulb at the end of the esophagus, and a long and pointed tail. PCR and sequencing techniques revealed the species of pinworm to be Synphacia obvelata. Even though the scope of the study was still limited, the results of the study provided information on the presence of S. obvelatain experimental mice and gave a warning signal about monitoring and eradication of pinworms for experimental animal facilities.
DOI: https://doi.org/10.31817/tckhnnvn.2024.22.5.
Isolation and Identification Biochemical Characteristics of Porcine Circovirus Type 2 (PCV2) from pigs in Some Northern Provinces of Vietnam

Huynh Thi My Le, Nguyen Van Giap

Date Received: 15-04-2013 / Date Accepted: 15-06-2013 / Date Published: 13-06-2025
The aim of this study was to isolate and identify biochemichal characteristics of PCV2formpigs with PCVAD in 4 nothern provinces of Vietnam (Hanoi, Hoa Binh, Bac Giang and Hai Duong). Isolation of PCV2 would be a conclusive evidence to confirm the circulation of PCV2 and PCVAD in pigs of Vietnam. 8 of PCV2 were isolated from 38 samples collected from pigs with suspected PCVAD. PCV2 isolates were PCV2b genotype. The result of identification biochemical characteristics of isolated PCV2 shown that PCV2 could multiply in PK15 cell culture from the first or second passage, but no CPE was observed. TCID50of all ranging from 102,7to104,2 /ml.
DOI: https://doi.org/10.31817/tckhnnvn.2013.11.3.
Farmers’ Assessment on Implementation of Agricultural Support Policy for Poverty Reduction in Van Xuan and Ngoc Phung Communes, Thuong Xuan District, Thanh Hoa Province

Do Kim Chung, Hoang Thi Hang

Date Received: 05-10-2015 / Date Accepted: 04-11-2015 / Date Published: 13-06-2025
This research study reportsassessments of 250 farmhouseholdsin thetwo extremely difficult communesinThuong Xuan district, Thanh Hoa province on implementation of agricultural support policy for poverty reduction. Findings indicate thatthe majority of farmers expressed positive viewpoints on beneficiary identification process, accessibility, supports received and appropriateness of agricultural supportive policies for poverty reduction. Farmers also perceived that supportive policies have strong impacts on poverty reduction. However, poverty rate in the communes remainedhigh and reduced slowly. The situation was ascribedtoimproper beneficiary identification process, low accessibility of the poor, inappropriate planning, weak capacity for policy implementation and shortcomings in supportive policy design. The research also pointedout some measures to improve effectiveness and efficiencies of supportive policies for poverty reduction such as improvement of planning, renovating policy implementation process, propaganda of policies, enhancing implementers’ capacity, mobilizing resources and renovation of policy from free input subsidies to support a development of a full value change in agricultural productionandsettingout relief from supportive policies
DOI: https://doi.org/10.31817/tckhnnvn.2015.13.7.
Building Image Database and Retrieval System for Rice Seed Identification

Tran Thi Thu Huyen, Nguyen Thi Thao, Nguyen Thi Thuy, Hoang Thanh Tam, Vu Thi Luu

Date Received: 22-07-2015 / Date Accepted: 03-09-2015 / Date Published: 13-06-2025
This paper presents a database of rice seeds properties to aid users in the assessment and recognition of seed characteristics of rice varieties based on their apprearance. Inspired by practical demands in quality control and rice seed purity assessment in seed production, we collected rice seeds of different varieties, acquired their images and consulted with experts about the visual properties for rice variety identification. As a result, we built a database of rice seed properties accompanied with their images and the description of the visual features. The database included popular rice varieties in the northern delta of Viet Nam. A database management system (DBMS) was built for managing and searching for rice seeds in the database. A web-based version of the DBMS was also developed. The system can be used to search for different rice varieties based on name and/or the description of the seed appearance. It can help users to learn about rice seed varieties, their visual features for discrimination and recognition. The system is easy to use, especially for non-IT users such as technicians, agronomy students or rice experts of rice seed production companies. This is also the first web-based database of rice varieties in Viet Nam with rice seed images to support rice seed searching and recognition.
DOI: https://doi.org/10.31817/tckhnnvn.2015.13.6.
Phân biệt hai loài cá trê (Clarias macrocephalusvà C. gariepinus) và con lai của chúng bằng phương pháp PCR-RFLP

Duong Thuy Yen

Date Received: 08-05-2015 / Date Accepted: 25-08-2015 / Date Published: 13-06-2025
Cá trê lai (Clarias macrocephalusx Clarias gariepinus) được nuôi phổ biến ở Việt Nam và có thể thất thoát ra ngoài môi trường tự nhiên. Việc xác định đúng cá thể con lai trở nên quan trọng trong quản lý nguồn lợi cũng như trong nuôi trồng thủy sản. Phân biệt con lai dựa vào hình thái thường không chính xác. Nghiên cứu này sử dụng phương pháp PCR-RFLP đối với gien ti thể (Cytochrome C oxidase subunit I, COI) và gien trong nhân (Rhodopsin, rho) để phân biệt con lai với hai loài bố mẹ. Mười hai mẫu cá (6 mẫu cho mỗi loài) và 3 mẫu cá trê lai nuôi được giải trình tự 2 gien trên. Sau đó, trình tự gien của hai loài được sắp xếp thẳng hàng để tìm enzym cắt giới hạn đặc trưng cho loài. Hai enzym SpeI và XcmI được chọn để cắt hai gien tương ứng, COI và rho. Kết quả khẳng định cá trê vàng C. macrocephaluslà loài cá mẹ của con lai đang được nuôi hiện nay. Chromatogram và phân đoạn gien rho sau khi bị cắt bởi enzym XcmI của con lai thể hiện đặc điểm trung gian của hai loài bố mẹ. Như vậy, phương pháp phân tích PCR-RFLP gien COI và rho là phương pháp hiệu quả và chính xác để xác định từng cá thể cá trê lai.
DOI: https://doi.org/10.31817/tckhnnvn.2015.13.6.
Isolation and Rapid Identification by MALDI-TOF MS of Riemerella anatipestiferfrom Clinical Cases in Waterfowls in Ha Nam Province

Truong Quang Lam, Nguyen Thi Lan, Nguyen Thi Thu Huong, Dao Le Anh, Tran Danh Son

Date Received: 01-06-2021 / Date Accepted: 10-01-2022
This study aimed to isolate and identify by PCR and MALDI-TOF MS of Riemerella anatipestifer(RA) strains isolated from ducks and muscovy ducks in Ha Nam province. Samples including brain, heart, liver, lung, and spleen were collected from 45 suspected ducks in the farms in Ly Nhan, Binh Luc, Duy Tien districts. Total 27 out of 45 ducks showed the appearance of suspected colonies with the following characteristics: small, transparent, non-hemolysis with the main biochemical features as negative for indole, positive for catalase and oxidase test, and did not grow on MacConkey agar plates. Rapid identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) showed that 27 suspected colonies were positive to RA. This result is 100% in agreement with the PCR results.
Selection, Identification and Determination of Some Cultural Conditions Affecting Cellulase Production of Lactic Acid Bacteria

Nguyen Thi Lam Doan, Peter Vandamme

Date Received: 20-05-2018 / Date Accepted: 09-07-2018
The purposesof this study wereto selectandidentify species of lactic acid bacteria (LAB) capable of producing high extracellular cellulase and to determine some cultural conditions affectingcellulase production of selected strains. Fortystrains producing extracellular cellulasewere selected from 120LAB strains isolated from some traditional fermented foods. Of40 strains producing extracellular cellulase, 10 strains produced cellulase withhigh enzyme activities with diameter of substrate hydrolyzing zone reachingfrom 11 to 15 mm. DP4.8 strainwithhighest cellulase productivitywas further investigated onthe effect of some culture conditions such as carboxymethyl cellulose (CMC) concentration, cultural temperature, cultural time on producing cellulase. Results showed that CMC concentration of 1.0%, culture temperature at 37oC, and culture time (36h) were the best conditionsfor producing cellulase.In addition, DP4.8 strain was analysedbypheSgenesequencingandcomparedwiththe known sequence database in EMBL and BCCM/LMG collection of Ghent University, Belgium. This strain was identified to be Lactobacillus rossiaes.
Isolationand Characterization of the Strain Arthrospira plastensisIsolated from Van Quan Lake

Nguyen Duc Bach, Chu Duc Ha, Vu Le Dieu Huong, Phi Thi Cam Mien

Date Received: 06-04-2021 / Date Accepted: 05-05-2021
Spirulina (Arthrospira platensis)is a species of Cyanobacteriaand is widelycultivated for functional foods, cosmeticsand aquaculture feed due to its rich protein, pigments, vitamins, unsaturated fatty acids and trace elements. In Vietnam, Spirulinawasfirst studiedin the late 1970s, mainlyfocused oninvestigating environmentaland nutritive factors aswell asculture techniques. However, very few studies on isolation, identification and characterization of native strain have been done. With the aim of exploiting the indigenous genetic resources, a strain of Cyanobacteria distributed in Van Quan lake (Hanoi) was isolated, identified and culturedinthe medium ofHoagland, BBM, BG-11, ½ Chu-10 and Zarrouk. Bymorphological analysis using optical and electron scanning microscopy combined with 16S rRNA sequence analysis, theisolated strain was identified as Arthrospira platensis. As the results attained, except for Zarroukmedia, this speciescan grow well inin BG-11and BBMmedia. The study provided an initial scientific basis for exploiting indigenous genetic resources for functional foods, cosmeticsand aquaculture feeds.
–galactosidase from Lactobacillus fermentumFV4: from Strain Identification to Characterization of Galacto-oligosaccharide Production of Enzyme

Nguyen Tien Thanh, Tran Thi Na, Nguyen Thi Lam Doan, Nguyen Hoang Anh

Date Received: 01-03-2021 / Date Accepted: 04-05-2021
This study was conducted to select, identify lactic acid bacteria strain producing enzyme -galactosidase with trans-galactosylation activity and determine the characteristics of enzyme applied in Galacto-oligosacchride (GOS) production. -galactosidase of lactic bacterial strain FV4 isolated from the fermented mustardhas been recorded as trans-galactosylation enzyme which converts lactose to GOS via the conversion product by using thin-layer chromatography (TLC).FV4 strain was identified and named Lactobacillus fermentum FV4 based on the comparison of sequence encoding for 16rRNA gene. Characterization of technical –galactosidase from this strain indicated that enzyme activity was the highest in the pH ranged from 6.5 to 8.5 and the most stable was at pH 7.5, after 24h of incubation in pH 7.5, the enzyme activity has still remained 92.8%. The optimal temperature of enzyme was 50Cand enzyme was very stable at 30Cin 24h of incubation. In addition, K+, Na+, DTT 1mM, 10mM, and Mg2+1mM activated the enzyme activity. Products of lactose conversion by using enzyme β-galactosidasewere analyzed based on TLC and HPLC showed that 65% lactose was converted to 8% GOS within 6h.
Variation in Morphometric Characteristics of Glossogobius aureusDistributed from Can Tho to Ca Mau

Phan Hoang Gieo, Dinh Minh Quang, Truong Trong Ngon, Nguyen Huu Duc Ton

Date Received: 19-02-2021 / Date Accepted: 12-03-2021
This study aimed to provide information on the morphometric variations of Glossogobius aureus, a commercial fish species in the Mekong Delta. A total of 742 individuals (282 males and 360 females) were collected during the dry and wet seasons (January 2020 to December 2020) at four studied sites (Cai Rang, Can Tho; Long Phu, Soc Trang; Hoa Binh, Bac Lieu; and Dam Doi, Ca Mau). The results showed that total length and body weight of this species varied along with seasons and studied sites, but not genders. There were no significant differences in all morphological characteristics were not significant difference except the body length and weight variations of the immature and mature fish. The studied site and season variables influenced the total length and body weight of this species. The results of the present study have provided useful information for this species identification and understanding of the ecological adaptation of the fish in the study locations.
Characterization of Ground-beetle Community Structure and Identification of ground-beetle Species as Bioindicators for Land use typesat Huu Lien Nature Reserve, Lang Son Province

Bui Van Bac, Le Minh Thu

Date Received: 07-10-2020 / Date Accepted: 29-01-2021
This study examined the differences in species composition and community structure of ground beetles among land use types of karst ecosystems in Huu Lien Nature Reserve (Lang Son Province). Pitfall traps were used to collect ground beetles. In total, 80 pitfall traps were established and distributed in four major types of land use comprising agricultural land, grassland, Acaciaplantations (10 years) and secondary forest (15 years). The study recorded 24 morphospecies of ground beetles from 477 trapped individuals. Agricultural land (maize field) had the highest abundance and species richness and a high level of diversity of ground beetles. The community structure of ground beetles significantly differed among the land uses. Particularly, the species ordination NMDS obviously separated the agricultural ground beetles from the forest communities. The litter layer significantly affected the community structure of ground beetles. The study found four ground-beetle species as bio-indicator species of the agricultural land based on the indicator value (IndVal), including: Pheropsophus jessoensis Morawitz, 1862, Chlaenius pleuroderusChaudoir, 1883, Harpalus indicusBates, 1891 and Chlaenius flavofemoratusLaporte, 1834.
Isolation and Identification of Soft Rot Bacteria on Dendrobium AnosmumOrchid and Evaluation of Inhibitory Effects of Some Actinomycetes

Pham Hong Hien, Diem Dang Truong, Duong Van Hoan, Tran Thi Dao, Nguyen Thi Thu, Nguyen Xuan Canh

Date Received: 20-07-2021 / Date Accepted: 09-12-2021
Bacterial soft rot is one of the most common diseases and mainly affects plants including orchid Dendrobium anosmum. The bacteria causing soft rot penetrates plant tissue, causing soft rot through the wound. This study aimed to íolate and identify bacterial strains capable of causing soft rot disease on orchids and select actinomycetes capable of antagonizing pathogenic bacterial strains. From five samples of orchid leaves showing symptoms of soft rot disease collected in Bac Giang, two strains of bacteria capable of causing soft rot disease were-isolated and the pathogenicity determined by artificial re-infection method. Bacterial strains were identified as Bacillus pumilusVK3 and B. altitudinisVK5B. By usingthe disk-diffusion method, from six Streptomycesstrains, XK7 Streptomycesstrain was selected for its antagonistic effect against B. pumilusVK3 and B. altitudinisVK5B-with the diameters of clear zone of17 ± 0,07mm and 14 ± 0,05mm, respectively.
Isolation, Selection and Identification of Strain of Enterococcus faeciumHN1 Capable of Producing Bacteriocin

Pham Hong Hien, Duong Van Hoan, Tran Thi Dao, Pham Thi Dung, Nguyen Thi Thu, Pham Thi Thu Trang, Nguyen Xuan Canh

Date Received: 14-06-2021 / Date Accepted: 16-02-2022
This study was carried out to identify lactic bacteria producing bacteriocin potentially as supplement in the aquaculture feeds to replace the antibiotics. Combining methods of spreading and observing morphological characteristics of the colony on MRS medium, 16 strains of lactic acid bacteria were isolated from 18 fish gut samples collected at different locations. Among these, 8 strains were able to produce bacteriocin showing antibacterial activity against Salmonellasp. and Escherichia coli. The strain HN1 isolated from Tilapiagut samples collected in Hanoi had the most vital bacteriocin - producing ability and exhibited strong antibacterial activity simultaneously against Salmonellasp. and Escherichia coliwith antibacterial ring diameters of 16mm and 15mm, respectively. On MRS medium supplemented with 3% glucose as a carbon source and 3% yeast extract as a nitrogen source, the strain HN1 was able to grow and produce the highest amount of bacteriocin. The combination of morphological, physiological, biochemical characteristics and analysis of molecular biological sequences has identified the strain HN1 as Enterococcus faecium.

1 - 25 of 76 items 1 2 3 4 > >>

Search

Advanced filters

Search Results