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Biotechnology and Applied Biochemistry

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https://www.readbyqxmd.com/read/28887814/construction-and-application-of-an-electrochemical-biosensor-based-on-an-endotoxin-aptamer
#1
GuoQing Ying, MinJun Wang, Yu Yi, JianShu Chen, JianFeng Mei, YanLu Zhang, ShuQing Chen
An electrochemical biosensor that used aptamer as a biological element was constructed to detect endotoxin. Biolayer interferometry was used to obtain the affinity constant of an aptamer for Lipopolysaccharide, which had a equilibrium dissociation constant of 22.9 nM. The amine-terminated aptamer was then assembled on a gold electrode surface using 3-mercaptopropionic acid as a intermediate linker. The modification of the gold electrode was confirmed by cyclic voltammetry and electrochemical impedance spectroscopy...
September 9, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28881487/improving-properties-of-silk-sericin-membranes-via-enzymatic-oxidation-with-laccase-and-tempo
#2
Qian Zhang, Li Cui, Ping Wang, Chao Deng, Qiang Wang, Xuerong Fan
Silk sericin has excellent features of anti-oxidant ability and good cytocompatibility, however, high water solubility and poor mechanical properties have restricted its application in biomedical fields. In this study, aimed at improving the mechanical properties of a regenerated silk sericin, the primary hydroxy groups in silk sericin were enzymatically oxidized by using laccase and 2,2',6,6'-tetramethylpiperidine-N-oxyl (TEMPO), and the generated reactive groups then reacted further with the amino groups in the sericin chains...
September 7, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28881090/an-activity-transition-from-nadh-dehydrogenase-to-nadh-oxidase-during-protein-denaturation
#3
Scott Huston, John Collins, Fangfang Sun, Ting Zhang, Timothy D Vaden, Y-H Percival Zhang, Jinglin Fu
A decrease in the specific activity of an enzyme is commonly observed when the enzyme is inappropriately handled or is stored over extended period. Here, we reported a functional transition of a FMN-bound diaphorase (FMN-DI) that happened during the long-term storage process. It was found that FMN-DI did not simply lose its NADH dehydrogenase activity after a long-time storage, but obtained a new enzyme activity of NADH oxidase. Further mechanistic studies suggested that the alteration of the binding strength of a FMN cofactor with a DI protein could be responsible for this functional switch of the enzyme...
September 7, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28877377/membrane-cholesterol-effect-on-the-5-ht2a-receptor-insights-into-the-lipid-induced-modulation-of-an-antipsychotic-drug-target
#4
Juan Manuel Ramírez-Anguita, Ismael Rodríguez-Espigares, Ramon Guixà-González, Agostino Bruno, Mariona Torrens-Fontanals, Alejandro Varela-Rial, Jana Selent
The serotonin 5-hydroxytryptamine 2A (5-HT2A ) receptor is a G-protein-coupled-receptor (GPCR) relevant for the treatment of CNS disorders. In this regard, neuronal membrane composition in the brain plays a crucial role in the modulation of the receptor functioning. Since cholesterol is an essential component of neuronal membranes, we have studied its effect on the 5-HT2A receptor dynamics through all-atom MD simulations. We find that the presence of cholesterol in the membrane increases receptor conformational variability in most receptor segments...
September 6, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28876471/taxadiene-5%C3%AE-ol-is-a-minor-product-of-cyp725a4-when-expressed-in-escherichia-coli
#5
Laxmi Sagwan-Barkdoll, Aldwin M Anterola
CYP725A4 is a P450 enzyme from Taxus cuspidata that catalyzes the formation of taxadiene-5α-ol (T5α-ol) from taxadiene in paclitaxel biosynthesis. Past attempts expressing CYP725A4 in heterologous hosts reported the formation of 5(12)-oxa-3(11)-cyclotaxane (OCT) and/or 5(11)-oxa-3(11)-cyclotaxane (iso-OCT) instead of, or in addition to, T5α-ol. Here we report that T5α-ol is produced as a minor product by Escherichia coli expressing both taxadiene synthase (TS) and CYP725A4. The major products were OCT and iso-OCT, while trace amounts of unidentified monooxygenated taxanes were also detected by gas chromatography-mass spectrometry...
September 6, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28872702/enhancement-of%C3%A2-l-phenylalanine-production-in-escherichia-coli-by-heterologous-expression-of-vitreoscilla-hemoglobin
#6
Wei-Bin Wu, Xiao-Lei Guo, Ming-Liang Zhang, Qing-Gen Huang, Feng Qi, Jian-Zhong Huang
L-phenylalanine is an important amino acid that is widely used in the production of food flavors and pharmaceuticals. Generally, L-phenylalanine production by engineered Escherichia coli requires a high rate of oxygen supply. However, the co-expression of Vitreoscilla hemoglobin gene (vgb), driven bya tac promoter, with the genes encoding 3-deoxy-D-arabinoheptulosonate-7-phosphate synthetase (aroF) and feedback-resistant chorismate mutase/prephenate dehydratase (pheA(fbr) ), led to increased productivity and decreased demand for aeration by E...
September 5, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28857275/size-of-single-wall-carbon-nanotube-affects-the-folate-receptor-mediated-cancer-cell-targeting
#7
Fahimeh Charbgoo, Mehrdad Behmanesh, Maryam Nikkhah
Advances in nanobiotechnology and targeting strategy could improve the delivery of therapeutic molecules into cancer cells, leading to improved treatment efficiency with minimal side effects on normal cells. To design an efficient nanocarrier, consideration of parameters that facilitate direct drug delivery into the target cells is important. We studied the effect of single wall carbon nanotubes size on their cell internalization level via the folate receptor-mediated pathway through folic acid targeting. Folate-SWNTs were covalently synthesized and characterized...
August 30, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28833557/enhancing-recombinant-interleukin-6-production-yield-by-fermentation-optimization-two-steps-denaturing-2dr-and-one-step-purification
#8
Nadeem Ahmed, Rabbia Abbas, Mohsin Ahmad Khan, Hamid Bashir, Saad Tahir, Ahmad Usman Zafar
Interleukin-6 a pleiotropic cytokine involved in wide range biological activities. So the large scale Production of biologically active recombinant human interleukin-6 is important for its structural and functional studies. Here we report an optimized method for shake flask fermentation and simplified high yield purification procedure for the recombinant interleukin -6. This high yield expression method not only involves the optimization of the fermentation condition, but also the single step purification method as well as two-steps denaturing and one step refolding process (2DR)...
August 22, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28833498/generation-and-selection-of-na%C3%A3-ve-fab-library-for-parasitic-antigen-anti-bmsxp-antibodies-for-lymphatic-filariasis
#9
Noorsharmimi Omar, Nurul Hamizah Hamidon, Muhammad Hafiznur Yunus, Rahmah Noordin, Yee Siew Choong, Theam Soon Lim
Phage display has been applied successfully as a tool for the generation of monoclonal antibodies (mAbs). Naive antibody libraries are unique as they are able to overcome several limitations associated with conventional mAb generation methods like the hybridoma technology. Here, we performed an in vitro selection and generation of Fab antibodies against Brugia malayi SXP protein (BmSXP), a recombinant antigen for the detection of lymphatic filariasis. We developed a naïve multi ethnic Fab antibody library with an estimated diversity of 2...
August 21, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28833484/microbial-production-of-mannitol-by-lactobacillus-brevis-3-a5-from-concentrated-extract-of-jerusalem-artichoke-tubers
#10
Hailong Cao, Min Yue, Gang Liu, Yuguang Du, Heng Yin
In the present study, the conversion of the extract of Jerusalem artichoke tubers for mannitol production by Lactobacillus brevis 3-A5 was investigated. When the bacterium utilized enzymatic hydrolysates of Jerusalem artichoke extract as the main substrates in batch fermentation, the significant decrease in mannitol productivity was observed when the initial concentration of reducing sugar increased. Then, a strategy of continuous fed-batch fermentation was adopted for improving mannitol production with enzymatic hydrolysates of Jerusalem artichoke extract as main substrates...
August 17, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28833445/in-silico-mapping-of-allosteric-ligand-binding-sites-in-type-1-cannabinoid-receptor
#11
Annalaura Sabatucci, Daniel Tortolani, Enrico Dainese, Mauro Maccarrone
The recent resolution of the crystal structure of type-1 cannabinoid receptor (CB1 ), and the discovery of novel modulators for this target open the way to the possibility of elucidating the structural requirements for CB1 binding, and thereby facilitate a rational drug design. Compounds that target the orthosteric site of CB1 in some cases have shown side effects. Allosteric modulators could potentially avoid these side effects by influencing binding and/or efficacy of orthosteric ligands. Here, we summarize and compare previous data on different putative allosteric binding sites observed in CB1 homology models with an in silico docking study of the recently published crystal structure of the same receptor on endogenous and natural hydrophobic ligands that act as positive allosteric modulators (PAMs) and negative allosteric modulators (NAMs) of CB1 ...
August 17, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28805269/cloning-and-bacterial-expression-systems-for-recombinant-human-heparanase-production-substrate-specificity-investigation-by-docking-of-a-putative-heparanase-substrate
#12
Angela Pennacchio, Alessandro Capo, Simonetta Caira, Annabella Tramice, Antonio Varriale, Maria Staiano, Sabato D'Auria
Human heparanase (HPSE) is an enzyme that degrades the extracellular matrix. It is implicated in a multiplicity of physiological and pathological processes encouraging angiogenesis and tumor metastasis. The protein is a heterodimer composed from a subunit of 8 kDa and a subunit of 50 kDa. The two protein subunits are non-covalently associated. The cloning and expression of the two protein subunits in Escherichia coli, and their subsequent purification to homogeneity under native conditions result in the production of an active heparanase enzyme...
August 14, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28795444/prediction-of-shorter-oligonucleotide-sequences-recognizing-aflatoxin-m1
#13
Amit Kumar Pandey, Yudhishthir Singh Rajput, Dheer Singh, Rajan Sharma
Aflatoxin M1 (AFM1) is present in milk of lactating animals fed on aflatoxin B1 contaminated feeds. Aptamers are new emerging ligand molecules and can be employed in assay protocols. Shorter aptamers have several advantages. Untruncated (72-nucleotide long) and truncated (18- to 42-nucleotide long) aptamers were evaluated for AFM1 recognition that was detected by color change in aptamer-conjugated gold nanoparticles in the presence of AFM1. Truncation of 10 aptamers was designed to retain motifs. Untruncated and truncated aptamers recognized AFM1...
August 10, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28791765/effects-of-gelling-bath-on-the-physical-properties-of-alginate-gel-beads-and-the-biological-characteristics-of-entrapped-hepg2-cells
#14
Dongsheng Sun, Yang Liu, Hao Wu, Ying Ren, Xiaojun Ma, Huijian Wu, Guangwei Sun
Optimizing alginate gel beads is necessary to support the survival, proliferation, and function of entrapped hepatocytes. In this study, gelling bath was modified by decreasing calcium ion concentration and increasing sodium ion concentration. Alginate gel beads (using 36% G sodium alginate) prepared in the modified gelling bath had more homogeneous structure and better mass transfer properties compared with the traditional gelling bath that contains only calcium ions. Moreover, Alginate gel beads generated in the modified gelling bath could significantly promote the HepG2 cell proliferation and the growth of cell spheroids, and maintain the albumin secretion ability similar to alginate gel beads prepared in the traditional gelling bath with only calcium ions...
August 9, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28791738/metformin-promotes-neuronal-differentiation-and-neurite-outgrowth-through-ampk-activation-in-human-bone-marrow-mesenchymal-stem-cells
#15
Min-Ji Ahn, Goang-Won Cho
Metformin is an AMP-activated kinase (AMPK) activator that plays a role in glucose energy metabolism and cell protection. It is widely used to treat several diseases, including type 2 diabetes, cardiovascular diseases, cancer, and metabolic diseases. In this study, we investigated whether AMPK activation upon treatment with metformin may promote neurite outgrowth during the progression of neuronal differentiation in human bone marrow-mesenchymal stem cells (hBM-MSCs). Differentiation of metformin-treated MSCs (Met-MSCs to Met-diMSCs) in the neuronal induction media resulted in an increase in the number of differentiated cells in a metformin concentration dependent manner...
August 9, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28791741/molecular-dynamics-study-on-the-apo-and-holo-forms-of-5-lipoxygenase
#16
Juan Torras, Mauro Maccarrone, Enrico Dainese
Lipoxygenases (LOXs) are nonheme iron-containing enzymes catalyzing the dioxygenation of polyunsaturated fatty acids. LOX catalytic activity depends on the presence of iron in the active site and the iron removal is also able to affect the membrane binding properties of the enzyme. Leukotrienes biosynthesis is initiated by the action of 5-LOX at the level of nuclear membrane and the mechanism of enzyme-membrane interaction is thought to involve structural flexibility and conformational changes at the level of the protein tertiary structure...
August 8, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28779486/construct-a-gene-to-metabolite-network-to-screen-the-key-genes-of-triterpene-saponin-biosynthetic-pathway-in-panax-notoginseng
#17
Ning Wang, Long Wang, Lianwen Qi, Xu Lu
Triterpene saponins are main active constituents of Panax notoginseng. Metabolites profiling of 12 triterpene saponins was analyzed by high-performance liquid chromatography-mass spectrometry in leaf, petiole, and root extracts of P. notoginseng. Most of the 20(S)-protopanaxatriol (PPT) type saponins, except ginsenoside Re, were mainly distributed in roots, while 20(S)-protopanaxadiol (PPD) type saponins were detected among various tissues. The total content of PPD-type saponins decreased in the order of leaf, petiole, and root...
August 4, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28770577/sec-saxs-and-hdx-ms-a-powerful-combination-the-case-of-the-calcium-binding-domain-of-a-bacterial-toxin
#18
REVIEW
Darragh P O'Brien, Sébastien Brier, Daniel Ladant, Dominique Durand, Alexandre Chenal, Patrice Vachette
Small-angle X-ray Scattering (SAXS) is a relatively simple experimental technique that provides information on the global conformation of macromolecules in solution, be they fully structured, partially, or extensively unfolded. Size Exclusion chromatography in line with a SAXS measuring cell considerably improves the mono-dispersity and ideality of solutions, the two main requirements of a "good" SAXS sample. Hydrogen/Deuterium eXchange monitored by Mass Spectrometry (HDX-MS) offers a wealth of information regarding the solvent accessibility at the local (peptide) level...
August 2, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28762562/co-expression-of-alpha-1-antitrypsin-with-cytoplasmic-domain-of-v-snare-in-pichia-pastoris-preserving-biological-activity-of-alpha-1-antitrypsin
#19
Maryam Khatami, Seyed Nezamedin Hosseini, Sadegh Hasannia
Alpha-1-antitrypsin (A1AT) is a major serum protein in human with protease inhibitory activity. Because of its extensive application in medicine, recombinant DNA technology has been considered for its production. The current study is going to examine co-expression of A1AT, and soluble domain of v-SNARE in Pichia pastoris, which can prevent the secretion of A1AT after passing the secretory pathway thoroughly. This was done mainly to preserve the biological activity of A1AT which in the secretory mode might be impaired in the fermentation and early clarification conditions...
August 1, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28762559/improvement-of-amphotericin-b-production-by-a-newly-isolated-streptomyces-nodosus-mutant
#20
Bo Zhang, Hai-Dong Zhang, Yi-Teng Zhou, Kai Huang, Zhi-Qiang Liu, Yu-Guo Zheng
Amphotericin B is an effective antifungal antibiotic. However, its production in the wild-type strain of Streptomyces nodosus is relatively low. In this study, a strain of ZJB 20130827, capable of producing amphotericin B, was isolated and identified as Streptomyces nodosus, based on its physiological and biochemical characteristics as well as its 16S rRNA gene sequence analysis. With N-methyl-N-nitroso-N'-nitroguanidine (NTG) and ultraviolet (UV) treatment, this wild-type strain was mutated for improving the yield of amphotericin B...
August 1, 2017: Biotechnology and Applied Biochemistry
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