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Biotechnology Letters

Xu Ding, Xiao-Ling Tang, Ren-Chao Zheng, Yu-Guo Zheng
OBJECTIVE: Rational engineering of the crevice-like binding site of lipases for improvement of lipases' catalytic properties. RESUTS: The residues located at the crevice-like binding site of four representative lipases including Thermomyces lanuginosus lipases (TLL and Lip), Rhizopus oryzae lipase (ROL), and Rhizomucor miehei lipase (RML) were identified through structural analysis. The residues at the bottom of the crevice-like binding site recognizing the substrates with short/medium carbon chain length and those located at the right-hand wall of the surface crevice region affecting the product release were changed by site-directed mutagenesis...
November 3, 2018: Biotechnology Letters
Sarah Schmitz, Volker Nölle, Skander Elleuche
OBJECTIVES: Metal-ion independent non-specific nucleases are of high potential for applications in EDTA-containing bioprocessing workflows. RESULTS: A novel extracellular non-specific nuclease EcNuc from the enterobacterium Escherichia coli has been identified. The recombinant gene was expressed and the protein was purified. Maximum activity of the enzyme was detected at 41.7 °C and at an acidic pH of 5.8. EcNuc tolerates EDTA in the reaction buffer at concentrations of up to 20 mM and the activity is not impaired by high concentrations of mono- and divalent metal ions in the absence of EDTA...
November 2, 2018: Biotechnology Letters
Tingting Chen, Yiyao Zhou, Yinghua Lu, Haoran Zhang
Heterologous biosynthesis has been long pursued as a viable approach for high efficiency production of natural products with various industrial values. Conventional methods for heterologous biosynthesis use the mono-culture of an engineered microbe for accommodating the whole target biosynthetic pathway to produce the desired product. The emergence of modular co-culture engineering, which divides the pathway between multiple co-culture strains, presents a new perspective to conduct heterologous biosynthesis and improve the bioproduction performance of natural products...
October 31, 2018: Biotechnology Letters
Ali H Rabbad, Clement Agoni, Fisayo A Olotu, Mahmoud E Soliman
OBJECTIVE: Bacterial RNA polymerase (bRNAP) represent a crucial target for curtailing microbial activity but its structural and sequence similarities with human RNA polymerase II (hRNAPII) makes it difficult to target. Recently, Pseudouridimycin (PUM), a novel nucleoside analogue was reported to selectively inhibit bRNAP and not hRNAP. Till date, underlying mechanisms of PUM selectivity remains unresolved, hence the aim of this study. RESULTS: Using sequence alignment method, we observed that the β' of bRNAP and the RPB1 subunits of hRNAPII were highly conserved while the β and RPB2 subunits of both proteins were also characterized by high sequence variations...
October 30, 2018: Biotechnology Letters
Shehnaz Ahmed, Veeren M Chauhan, Amir M Ghaemmaghami, Jonathan W Aylott
Bioreactors hold a lot of promise for tissue engineering and regenerative medicine applications. They have multiple uses including cell cultivation for therapeutic production and for in vitro organ modelling to provide a more physiologically relevant environment for cultures compared to conventional static conditions. Bioreactors are often used in combination with scaffolds as the nutrient flow can enhance oxygen and diffusion throughout the 3D constructs to prevent the formation of necrotic cores. A variety of scaffolds have been fabricated to achieve a structural architecture that mimic native extracellular matrix...
October 27, 2018: Biotechnology Letters
Xian Li, Bo Wu, Kan Zhou, Chengjian Jiang, Peihong Shen
OBJECTIVE: To identify potential target genes involved in L-serine biosynthesis in Methylobacterium sp. MB200 and to evaluate the gnd genetically-engineered strains for L-serine production. RESULTS: Five genes that are not associated with the central metabolic pathway but with L-serine biosynthesis were identified from Methylobacterium sp. MB200 mutants. Gene gnd, encoding 6-phosphogluconate dehydrogenase (PGDH), was selected for further evaluation. The gnd deletion mutant showed a 600% increase in D-serine tolerance and an 80% decrease in PGDH activity compared to Methylobacterium sp...
October 25, 2018: Biotechnology Letters
Christina Kyung Eun Baek, Chang-Ho Baek
OBJECTIVES: Designing a polypeptide sequence to interact with a preselected target polypeptide sequence of a protein has long been of interest, yet remains an elusive goal. RESULTS: Here, we propose a novel concept named "Clustered Complementary Amino Acid Pairing (CCAAP)," which plays an essential role in protein-protein interaction (PPI). Complementary amino acid pairing (CAAP) is a pairing between two amino acids encoded by a codon and its reverse complementary codon...
October 24, 2018: Biotechnology Letters
Wei Zhang, Yu Wang, Junzhe Wan, Pengbo Zhang, Fei Pei
OBJECTIVE: Mitochondrial dysfunction plays a pivotal role in various pathophysiological processes of heart. Cytochrome oxidase subunit 6B1 (COX6B1) is a subunit of cytochrome oxidase. METHODS: Cardiomyocytes were isolated from neonatal SD rats (within 24 h of birth) by repeating digestion of collagenase and trypsin. COX6B1 over-expression and hypoxia/reoxygenation was conducted on neonatal rat cardiomyocytes. Cell viability, apoptosis rates, mitochondria membrane potential and mitochondrial permeabilization transition pores (mPTPs) were then determined respectively by Cell performing Counting Kit-8 (CCK-8), Annexin-V/PI assay, JC-1 assay, mPTP assay...
October 11, 2018: Biotechnology Letters
Priyanka Jha, Vijay Kumar
Plants have evolved a number of transcription factors, many of which are implicated in signaling pathways as well as regulating diverse cellular functions. BABY BOOM (BBM), transcription factors of the AP2/ERF family are key regulators of plant cell totipotency. Ectopic expression of the BBM gene, originally identified in Brassica napus, has diverse functions in plant cell proliferation, growth and development without exogenous growth regulators. The BBM gene has been implicated to play an important role as a gene marker in multiple signaling developmental pathways in plant development...
December 2018: Biotechnology Letters
Zahra Payandeh, Effat Noori, Bahman Khalesi, Maysam Mard-Soltani, Jalal Abdolalizadeh, Saeed Khalili
CD37 is a member of tetra-spanning superfamily (characterized by their four transmembrane domains). It is one of the specific proteins for normal and malignant mature B cells. Anti CD37 monoclonal antibodies are reported to improve the overall survival in CLL. These therapeutics will increase the efficacy and reduce the toxicity in patients with both newly diagnosed and relapsed and refractory disease. Recent clinical trials have shown promising outcomes for these agents, administered both as monotherapy and in combination with standard chemotherapeutics...
December 2018: Biotechnology Letters
Ryoichi Sakiyama, Hiroyuki Hamada, Brandon Blau, Nora Freyer, Katrin Zeilinger, Frank Schubert, Toshio Miki
OBJECTIVES: To determine the most efficient design of a hollow fiber-based bioreactor device for a bioartificial liver support system through comparative bioengineering evaluations. RESULTS: We compared two types of hollow fiber-based bioreactors, the interwoven-type bioreactor (IWBAL) and the dialyzer-type bioreactor (DBAL), by evaluating the overall mass transfer coefficient (K) and the convective coefficient (X). The creatinine and albumin mass transfer coefficients and convective coefficients were calculated using our mathematical model based on the homoporous theory and the modified Powell method...
December 2018: Biotechnology Letters
Uriel Gutiérrez-Gómez, Martín P Soto-Aceves, Luis Servín-González, Gloria Soberón-Chávez
OBJECTIVE: To construct Pseudomonas aeruginosa PA14 derivatives that overproduce rhamnolipids (RL) by blocking the synthesis of the carbon-storage polymer polyhydroxyalkanoates (PHA) and by overexpressing the rhlAB-R operon that encodes for enzymes of RL synthesis and the RhlR transcriptional regulator. RESULTS: In contrast to previous results showing that overexpression of rhlAB-R genes in two P. aeruginosa strains (PAO1 and ATCC 9027) is sufficient to overproduce RL, we show that a PA14 derivative overexpressing the rhlAB-R operon did not increase the synthesis of these biosurfactants...
December 2018: Biotechnology Letters
Ying Wang, Guo-Si Li, Pei Qiao, Ling Lin, Hai-Long Xue, Li Zhu, Mian-Bin Wu, Jian-Ping Lin, Li-Rong Yang
OBJECTIVE: To strengthen NADH regeneration in the biosynthesis of L-2-aminobutyric acid (L-ABA). RESULTS: L-Threonine deaminase (L-TD) from Escherichia coli K12 was modified by directed evolution and rational design to improve its endurance to heat treatment. The half-life of mutant G323D/F510L/T344A at 42 °C increased from 10 to 210 min, a 20-fold increase compared to the wild-type L-TD, and the temperature at which the activity of the enzyme decreased by 50% in 15 min increased from 39 to 53 °C...
December 2018: Biotechnology Letters
Zhe Yang, Shihao Chen, Songlei Xue, Xinxiu Li, Zhen Sun, Yu Yang, Xuming Hu, Tuoyu Geng, Hengmi Cui
OBJECTIVES: To investigate the effect of endogenous Cas9 on genome editing efficiency in transgenic zebrafish. RESULTS: Here we have constructed a transgenic zebrafish strain that can be screened by pigment deficiency. Compared with the traditional CRISPR injection method, the transgenic zebrafish can improve the efficiency of genome editing significantly. At the same time, we first observed that the phenotype of vertebral malformation in early embryonic development of zebrafish after ZFERV knockout...
December 2018: Biotechnology Letters
Zihang Li, Junli Zhao, Niaz Muhammad, Dongyang Wang, Qinwen Mao, Haibin Xia
OBJECTIVES: To establish a HEK293 cell line with a luciferase knock-in reporter controlled by the endogenous SREBP1 promoter for investigating transcriptional regulation of the SREBP1 gene. RESULTS: PCR confirmed the site-specific integration of a single copy of the exogenous luciferase gene into one allele of the genome and a 14 bp deletion of the targeted sequence in the other. Luciferase activity was directly correlated with the promoter activity of the endogenous SREBP1 gene in the HEK293-SREBP1-T2A-luciferase-KI cell line cell line...
December 2018: Biotechnology Letters
Mengjuan Liu, Jiaqi Wang, Hongping Tang, Li Fan, Liang Zhao, Hai-Bin Wang, Yan Zhou, Wen-Song Tan
OBJECTIVE: To explore the impact of taurine on monoclonal antibody (mAb) basic charge variants in Chinese hamster ovary (CHO) cell culture. RESULTS: In fed-batch culture, adding taurine in the feed medium slightly increased the maximum viable cell density and mAb titers in CHO cells. What's more, taurine significantly decreased the lysine variant and oxidized variant levels, which further decreased basic variant contents from 32 to 27%. The lysine variant content in the taurine culture was approximately 4% lower than that in control condition, which was the main reason for the decrease in basic variants...
December 2018: Biotechnology Letters
Jayanthi Nagappan, Chiew Foan Chin, Lee Pei Lee Angel, Richard M Cooper, Sean T May, Eng-Ti Leslie Low
The first and most crucial step of all molecular techniques is to isolate high quality and intact nucleic acids. However, DNA and RNA isolation from fungal samples are usually difficult due to the cell walls that are relatively unsusceptible to lysis and often resistant to traditional extraction procedures. Although there are many extraction protocols for Ganoderma species, different extraction protocols have been applied to different species to obtain high yields of good quality nucleic acids, especially for genome and transcriptome sequencing...
December 2018: Biotechnology Letters
Lihao Ge, Yuyan Wang, Yang Cao, Gang Li, Rui Sun, Peng Teng, Yansong Wang, Yunlong Bi, Zhanpeng Guo, Yajiang Yuan, Deshui Yu
MicroRNA-429(miR-429) plays an important role in mesenchymal stem cells. Hypoxia-inducible factor 1α (HIF-1α) is a nuclear transcription factor that regulates the proliferation, apoptosis and tolerance to hypoxia of mesenchymal stem cells. HIF-1α is also a target gene of miR-429. We investigated whether miR-429 plays a role in hypoxia tolerance with HIF-1α in human amniotic mesenchymal stem cells (hAMSCs). The expression of miR-429 was increased by hypoxia in hAMSCs. miR-429 expression resulted in decreased HIF-1α protein level, but little effect on HIF-1α mRNA...
December 2018: Biotechnology Letters
Lakshmi Tripathi, Victor U Irorere, Roger Marchant, Ibrahim M Banat
Surfactants and emulsifiers are surface-active compounds (SACs) which play an important role in various industrial processes and products due to their interfacial properties. Many of the chemical surfactants in use today are produced from non-renewable petrochemical feedstocks, while biosurfactants (BS) produced by microorganisms from renewable feedstocks are considered viable alternatives to petroleum based surfactants, due to their biodegradability and eco-friendly nature. However, some well-characterised BS producers are pathogenic and therefore, not appropriate for scaled-up production...
December 2018: Biotechnology Letters
Hala S Helal, Amro Hanora, Rania Abdelmonem Khattab, Hayam Hamouda, Hamdallah Zedan
OBJECTIVE: The objective of this work was to isolate bacteria from Red Sea invertebrates, determine their antimicrobial activity, and screen for the biosynthetic gene clusters [polyketides (PKs) and nonribosomal peptides (NRPs)] which could be involved in the production of bioactive secondary metabolites. RESULT: Eleven different samples of marine invertebrates' were collected from Egypt's Red Sea (El-Tor-Sharm El-Sheikh and Hurghada) by scuba diving, and a total 80 isolates of the associated microorganisms were obtained from the cultivation on six different cultural medium...
December 2018: Biotechnology Letters
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