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Biotechnology Letters

Young-Jun Choi, Hyemin Kim, Ji-Woo Kim, Seokjoo Yoon, Han-Jin Park
OBJECTIVES: The aim of the study is to generate a spherical three-dimensional (3D) aggregate of hepatocyte-like cells (HLCs) differentiated from human embryonic stem cells and to investigate the effect of the 3D environment on hepatic maturation and drug metabolism. RESULTS: Quantitative real-time PCR analysis indicated that gene expression of mature hepatocyte markers, drug-metabolizing enzymes, and hepatic transporters was significantly higher in HLCs cultured in the 3D system than in those cultured in a two-dimensional system (p < 0...
February 20, 2018: Biotechnology Letters
Chih-Yao Chui, Pierre-Alexis Mouthuy, Hua Ye
OBJECTIVE: To demonstrate that uniform poly(vinyl butyral) (PVB) fibres can be safely electrospun onto a monolayer of human dermal fibroblasts using a portable device. RESULTS: PVB in solvent mixtures containing various amounts of ethanol and water was electrospun. Six percent (weight-to-volume ratio) PVB in a 9:1 ethanol:water ratio was the solution with the highest content in water that could be electrospun into consistent fibres with an average diameter of 0...
February 15, 2018: Biotechnology Letters
Fei Ge, Longbao Zhu, Anna Aang, Ping Song, Wanzhen Li, Yugui Tao, Guocheng Du
Yeast has been increasingly used as a host for the expression of enzymes. Compared to other expression systems, the yeast expression system has many advantages including its suitability for large-scale fermentation and its ability to modify enzymes. When expressed in yeast, many recombinant enzymes are N-glycosylated, and this may play an important role in their activity, thermostability and secretion. Although the mechanism underlying this process is not clear, the regulation of N-glycosylation by introducing or eliminating N-glycosylation at specific sites has developed into an important strategy for improving the production or catalytic properties of recombinant enzymes...
February 15, 2018: Biotechnology Letters
Dianhui Wu, Guolin Cai, Xiaomin Li, Bing Li, Jian Lu
OBJECTIVES: To optimize the expression of type A ferulic acid esterase (FaeA) from Aspergillus niger in Pichia pastoris X-33 using codon optimization. RESULTS: Recombinant FaeA was purified from the fermentation broth, with the maximum specific activity of 48.4 ± 0.1 U mg-1. Adding it during mashing process for beer brewing raised the filtration rate by 14.5% while the turbidity and viscosity declined by 22 and 6.9%, respectively. Addition of FaeA increased the concentrations of free ferulic acid (FA) and arabinoxylan (AX) in the wort, while the polymeric arabinoxylans content declined significantly...
February 12, 2018: Biotechnology Letters
Dong Wei, Yuki Yuminaga, Jiping Shi, Jian Hao
OBJECTIVES: To investigate the outcomes of capsule lost on cell transformation efficiency and chemicals (1,3-propanediol, 2,3-butanediol, and 2-ketogluconic acid) production by Klebsiella pneumoniae. RESULTS: The cps gene cluster showed low sequence homology with pathogenic strains. The wza is a highly conserved gene in the cps cluster that encodes an outer membrane protein. A non-capsulated mutant was constructed by deletion of wza. Phenotype studies demonstrated that non-capsulated cells were less buoyant and easy to sediment...
February 10, 2018: Biotechnology Letters
Chenchen Zhang, Jingyu Lu, Duo Yang, Xia Chen, Yujun Huang, Ruixia Gu
OBJECTIVE: To investigate the aerotolerance of Lactobacillus rhamnosus hsryfm 1301 and its influencing factors. RESULTS: The growth rate of L. rhamnosus hsryfm 1301 weakened noticeably when the concentration of supplemented H2O2 reached 1 mM, and only 2% of all L. rhamnosus hsryfm 1301 cells survived in MRS broth supplemented with 2 mM H2O2 for 1 h. After pretreatment with 0.5 mM H2O2, the surviving cells of L. rhamnosus hsryfm 1301 in the presence of 5 mM H2O2 for 1 h increased from 3...
February 7, 2018: Biotechnology Letters
Kun He, Hong Sun, Hao Song
OBJECTIVES: To enhance the yield of 9α-hydroxy-4-androstene-3,17-dione (9-OHAD) from phytosterols, a phytosterol transport system was constructed in Mycobacterium sp. strain MS136. RESULTS: 9-OHAD can be produced via the controlled degradation of phytosterols by mycobacteria. This involves an active transport process that requires trans-membrane proteins and ATP. A phytosterol transport system from Mycobacterium tuberculosis H37Rv was constructed in Mycobacterium sp...
February 1, 2018: Biotechnology Letters
Noah D Weiss, Claus Felby, Lisbeth G Thygesen
OBJECTIVES: The biochemical conversion of lignocellulosic biomass into renewable fuels and chemicals provides new challenges for industrial scale processes. One such process, which has received little attention, but is of great importance for efficient product recovery, is solid-liquid separations, which may occur both after pretreatment and after the enzymatic hydrolysis steps. Due to the changing nature of the solid biomass during processing, the solid-liquid separation properties of the biomass can also change...
February 1, 2018: Biotechnology Letters
Sin-Tak Chu, Kuo-Hsuan Chien, Hsiu-Hsia Lin, Wei-Hao Wu, Jhih-Yun Jian, Woan-Fang Tzeng, Tzeon-Jye Chiou
OBJECTIVE: To establish a quick analytical method using quantitative PCR for marker gene analysis to identify the functions of iTreg cells and subsequently curtail the harvest time for iTreg cells. RESULTS: The data from the marker gene analysis indicated that varying proportions of iTreg cells could reveal the various expression levels of these genes. FoxP3 expression increased to a considerable degree. By using the same iTreg population, the mixed lymphocyte reaction assay was conducted for 5 days...
January 31, 2018: Biotechnology Letters
Haiyang Zhang, Yang Ou, Ting Chen, Lan Yang, Zicheng Hu
OBJECTIVES: In this study, a rapid sedimentation induced by combined coagulants and gradual shear was developed to harvest Chlorella vulgaris. RESULTS: The microalgal harvesting efficiency was observably promoted by the synergistic effect between FeCl3 and PAM, especially in the first 10 min. A higher harvesting efficiency, 95.61%, could be achieved within approximately 3 min due to the large and dense flocs generated by the combined coagulants. In contrast, the efficiencies were only 54...
January 30, 2018: Biotechnology Letters
Bing-Qian Su, Ying-Qian Han, Shuang-Shuang Fan, Sheng-Li Ming, Bo Wan, Wei-Fei Lu, Bei-Bei Chu, Guo-Yu Yang, Jiang Wang
OBJECTIVE: The purpose of the article is to evaluate the changes in lipid metabolism in bovine mammary-gland epithelial MAC-T cells after PKM2 knockdown. RESULTS: MAC-T cells stably expressing low levels of PKM2 were established with lentivirus-mediated small hairpin RNA. Although the knockdown of PKM2 had no effect on MAC-T cell growth, the reduced expression of PKM2 attenuated the mRNA and protein expression of key enzymes involved in sterol synthesis through the SREBP pathway...
January 30, 2018: Biotechnology Letters
Robert Minkner, Enoch Y Park
Virus-like particles (VLPs) are a promising and developing option for vaccination and gene therapy. They are also interesting as shuttles for drug targeting. Currently, several different gene expression systems are available, among which the silkworm expression system is known for its mass production capacity. However, cost-effective purification with high purity of the target protein is a particular bottleneck for this system. The present review evaluates the advances in the purification of VLPs, especially from silkworm larval hemolymph...
January 30, 2018: Biotechnology Letters
Yasumasa Mashimo, Masayasu Mie, Eiry Kobatake
OBJECTIVE: We explored the co-localization of multiple enzymes on a DNA backbone via a DNA-binding protein, Gene-A* (A*-tag) to increase the efficiency of cascade enzymatic reactions. RESULTS: Firefly luciferase (FLuc) and pyruvate orthophosphate dikinase (PPDK) were genetically fused with A*-tag and modified with single-stranded (ss) DNA via A*-tag. The components were assembled on ssDNA by hybridization, thereby enhancing the efficiency of the cascading bioluminescent reaction producing light emission from pyrophosphate...
January 23, 2018: Biotechnology Letters
H D Pardavé-Alejandre, J E Alvarado-Yaah, E N Pompa-Mera, J E Muñoz-Medina, B Sárquiz-Martínez, C E Santacruz-Tinoco, R G Manning-Cela, V Ortíz-Navarrete, C López-Macías, C R González-Bonilla
OBJECTIVES: To display a recombinant avidin fused to the autotransporter ShdA to bind biotinylated molecules on the surface of Escherichia coli. RESULTS: Two chimeric protein constructs containing avidin fused to the autotransporter ShdA were expressed on the surface of Escherichia coli DH5α. One fusion protein contained 476 amino acids of the ShdA α and β domains, whereas the second consisted of a 314 amino acid from α and truncated β domains. Protein production was verified by SDS-PAGE using an antibody to the molecular FLAG-tag...
January 22, 2018: Biotechnology Letters
Hugo R Soares, Ana I Almeida, Hélio A Tomás, Paula M Alves, Ana S Coroadinha
OBJECTIVE: Develop an engineered cell line containing two flexible gene expression systems enabling the continuous production of tailor-made recombinant gammaretrovirus with predictable productivities through targeted integration. RESULTS: Dual-FLEX cells (dFLEX) contain two independent recombinase-mediated cassette exchange (RMCE) systems which confer flexibility to the expression of different transgene and envelope combinations. The flexible envelope expression in dFLEX cells was validated by pseudotyping retrovirus particles with three different viral envelope proteins-GaLV, 4070A and VSV-G...
January 20, 2018: Biotechnology Letters
Can Li, Jianqun Lin, Ling Gao, Huibin Lin, Jianqiang Lin
OBJECTIVES: Production of gluconic acid by using immobilized enzyme and continuous stirred tank reactor-plug flow tubular reactor (CSTR-PFTR) circulation reaction system. RESULTS: A production system is constructed for gluconic acid production, which consists of a continuous stirred tank reactor (CSTR) for pH control and liquid storage and a plug flow tubular reactor (PFTR) filled with immobilized glucose oxidase (GOD) for gluconic acid production. Mathematical model is developed for this production system and simulation is made for the enzymatic reaction process...
January 18, 2018: Biotechnology Letters
Shuhao Huo, Feifei Zhu, Bin Zou, Ling Xu, Fengjie Cui, Wenhua You
OBJECTIVES: To demonstrate the effectiveness of a novel two-stage system coupling hydrolytic acidification with algal microcosms for the treatment of acrylonitrile butadiene styrene (ABS) resin-manufacturing wastewater. RESULTS: After hydrolytic acidification, the BOD5/COD ratio increased from 0.22 to 0.56, showing improved biodegradability of the wastewater. Coupled with hydrolytic acidification, the algal microcosms showed excellent capability of in-depth removal of COD, NH3-N and phosphorus with removal rates 83, 100, and 89%, respectively, and aromatic pollutants, including benzene, were almost completely removed...
January 18, 2018: Biotechnology Letters
Fengyu Kou, Jing Zhao, Jiao Liu, Cunmin Sun, Yanmei Guo, Zijian Tan, Feng Cheng, Zhimin Li, Ping Zheng, Jibin Sun
OBJECTIVE: To enhance the thermal and alkaline pH stability of the lysine decarboxylase from Escherichia coli (CadA) by engineering the decameric interface and explore its potential for industrial applications. RESULTS: The mutant T88S was designed for improved structural stability by computational analysis. The optimal pH and temperature of T88S were 7.0 and 55 °C (5.5 and 50 °C for wild-type). T88S showed higher thermostability with a 2.9-fold increase in the half-life at 70 °C (from 11 to 32 min) and increased melting temperature (from 76 to 78 °C)...
January 18, 2018: Biotechnology Letters
Ting-Ting Xiao, Xian Li, Jia-Li Feng, Yong Li
OBJECTIVES: We evaluated the potential effects of aspirin combined with vitamin D3 on cell proliferation and apoptosis in oral cancer cells. RESULTS: Compared to the untreated control or individual drug, the combinations of aspirin and vitamin D3 significantly decreased the rates of cell proliferation by CCK-8 assay, and caused higher rates of cell apoptosis in both CAL-27 and SCC-15 cells by Annexin V-FITC apoptosis assay and flow cytometry. Remarkably, the combined treatment with aspirin and vitamin D3 significantly suppressed the expression of Bcl-2 protein and p-Erk1/2 protein, examined by western blot analysis...
January 18, 2018: Biotechnology Letters
Kulbhushan Chaudhary, Anirudha Chattopadhyay, Dharmendra Pratap
Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system allows biologists to edit genomic DNA of any cell in precise and specific way, entailing great potential for crop improvement, drug development and gene therapy. The system involves a nuclease (Cas9) and a designed guide RNA that are involved in wide range of applications such as genome modification, transcriptional modulation, genomic loci marking and RNA tracking. The limitation of the technique, in view of resistance of thymidine-rich genome to Cas9 cleavage, has now been overcome by the use of Cpf1 nuclease...
January 17, 2018: Biotechnology Letters
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