Bax expression is optimal at low oxygen tension and constant agitation

Publication date: Available online 19 September 2019Source: Protein Expression and PurificationAuthor(s): Yi He, Yong Chen, Daniel L. Morris, Duck-Yeon Lee, Nico TjandraAbstractBax is a pro-apoptosis protein that translocates from the cytosol to the mitochondrial membrane upon initiation of programed cell death. Bax subsequently disrupts the mitochondria membrane, resulting in the release of cytochrome C which activates the downstream caspases. The structure of inactive Bax has been solved, but despite intensive investigation, the mechanism by which it regulates apoptosis is not established. The low yield of Bax expression in E. coli hampers efforts to elucidate the mechanism. Thus, we undertook a systematic study aimed at improving the yield of Bax. Bacteria were grown in a computer-controlled fermenter and expression was induced by addition of Isopropyl ß-d-1-thiogalactopyranoside (IPTG). The Bax expression level decreased continuously when the dissolved oxygen level was kept at 30%, which is non-limiting for E. coli. Alternatively, when oxygen input was decreased with constant agitation and air flow (or kLa), Bax yield increased by a factor of three. To make sure the short chain fatty acids generated during micro-aerobic fermentation had no adverse effect, their concentrations were closely monitored with HPLC and their effect on cell growth and Bax expression were investigated additionally using shake flasks. Through proteomic analysis using Tandem Mass Tag (TMT) lab...
Source: Protein Expression and Purification - Category: Biochemistry Source Type: research

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Publication date: Available online 15 October 2019Source: Journal of Microbiological MethodsAuthor(s): Laleh R. Kalankesh, Susana Rodríguez-Couto, Mohammad Ali Zazouli, Yousef Dadban Shahamat, Ramazan Ali Dianati, Mahdieh ArghianiAbstractIn the present study, SiO2-TiO2 hybrid nanomaterial and zeolite-TiO2 (Z-TiO2) composites were synthesized by the sol-gel method. Then, the antibacterial activity of the above-mentioned synthesized materials, SiO2 and zeolite (Z) was investigated by the disk diffusion method using Echerichia coli and Enterobacter aerogenes as test microorganisms. All the materials showed antibacteria...
Source: Journal of Microbiological Methods - Category: Microbiology Source Type: research
This article centers on two families of sequence-specific transcription factors: bZIP (basic leucine-zipper) proteins, exemplified by the AP-1 and CEBPβ recognition of 5mC; and bHLH (basic helix-loop-helix) proteins, exemplified by MAX and TCF4 recognition of 5caC. We discuss the impact of template strand DNA modification on the activities of DNA and RNA polymerases, and the varied tendencies of modifications to alter base pairing and their interactions with DNA repair enzymes.Graphical abstract
Source: Journal of Molecular Biology - Category: Molecular Biology Source Type: research
Publication date: Available online 15 October 2019Source: Protein Expression and PurificationAuthor(s): Jorge Duarte-Gutiérrez, Lilia Leyva-Carrillo, Miguel A. Martínez-Téllez, Rosa O. Méndez-Estrada, Monserrath Felix-Portillo, Gloria Yepiz-PlascenciaAbstractMetallothioneins (MT) are cysteine rich proteins with antioxidant capacity that participate in the homeostasis and detoxification of metals and other cellular processes, and help to counteract the oxidative stress produced by Reactive Oxygen Species (ROS). The production of ROS increases during several stress conditions, including metal into...
Source: Protein Expression and Purification - Category: Biochemistry Source Type: research
In this study, we characterized a K+-channel toxin gene, ImKTx96, from the venom gland cDNA library of the scorpion Isometrus maculates. The peptide deduced from the ImKTx96 precursor nucleotide sequence contains a signal peptide of 27 amino acid residues and a mature peptide of 29 residues with three disulfide bridges. Multiple sequence alignment indicated that ImKTx96 is similar with the scorpion toxins that typically target K+-channels. The recombined ImKTx96 peptide (rImKTx96) was expressed in the Escherichia coli system, and purified by GST-affinity chromatography and RP-HPLC. Results from whole-cell patch-clamp exper...
Source: Peptides - Category: Biochemistry Source Type: research
Publication date: 1 December 2019Source: Colloids and Surfaces B: Biointerfaces, Volume 184Author(s): Amir Yadegari, Jafar Khezri, Sadaf Esfandiari, Hossein Mahdavi, Ali Asghar Karkhane, Reza Rahighi, Rashid Heidarimoghadam, Lobat Tayebi, Ehsan Hashemi, Abbas FarmanyAbstractIn this paper, a bottom-up hydrothermal route is reported for the synthesis of oxygen and nitrogen co-decorated carbon quantum dots (CQDs) using ammonium hydrogen citrate (AHC) as a single precursor. DLS data approved the formation of 4.0 nm (average size) CQDs. XRD pattern shows the interlayer spacing (002) of 3.5 Å for CQDs, which is exactly...
Source: Colloids and Surfaces B: Biointerfaces - Category: Biochemistry Source Type: research
Publication date: Available online 15 October 2019Source: Colloids and Surfaces B: BiointerfacesAuthor(s): Yonglin Yu, Qichun Ran, Xinkun Shen, Hong Zheng, Kaiyong CaiAbstractAfter implantation into a host, titanium (Ti) orthopaedic materials are facing two major clinical challenges: bacterial infection and aseptic loosening, which directly determine the long-term survival of the implant. To endow Ti implant with self-defensive antibacterial properties and desirable osteo/angio-genic differentiation potentials, hyaluronic acid (HA)-gentamicin (Gen) conjugates (HA-Gen) and chitosan (Chi) polyelectrolyte multilayers were con...
Source: Colloids and Surfaces B: Biointerfaces - Category: Biochemistry Source Type: research
Publication date: Available online 15 October 2019Source: TrAC Trends in Analytical ChemistryAuthor(s): Sona Jain, Thyago Gois Costa Melo, Silvio Santana Dolabella, Juewen LiuAbstractWater-borne protozoan parasites like Cryptosporidium, Giardia, Entamoeba and Toxoplasma are responsible for 1.7 billion cases of diarrhea globally, representing the second most frequent reason for mortality among children under five. They show an environmentally resistant cyst/oocyst stage. Despite their importance, the standard analytical methods for their detection still rely on immunostaining followed by microscopic analysis. In recent year...
Source: TrAC Trends in Analytical Chemistry - Category: Chemistry Source Type: research
Publication date: Available online 15 October 2019Source: Journal of Photochemistry and Photobiology B: BiologyAuthor(s): Hongjie Zhou, Huiping Jiao, Jingwei Xu, Yulong Liu, Shujun WeiAbstractDesigning biomimetic biomaterials influenced by the common complex structure of hard tissues is yet a test these days. The control of bio-mineralization procedure onto biomaterials should be assessed before the use in medical applications. Coming to the bone rejuvenation applications, this work assessed the in vitro antibacterial activity and interacting between osteoblast cells (MG63) on poly (hydroxypropyl methacrylate) (PHPMA) cryo...
Source: Journal of Photochemistry and Photobiology B: Biology - Category: Speech-Language Pathology Source Type: research
Authors: Bader MS, Loeb M, Leto D, Brooks AA Abstract Urinary tract infections (UTIs) caused by antibiotic- resistant Gram-negative bacteria are a growing concern due to limited treatment options. Knowledge of the common uropathogens in addition to local susceptibility patterns is essential in determining appropriate empiric antibiotic therapy of UTIs. The recommended first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females is a 5-day course of nitrofurantion, a 3-g single dose of fosfomycin tromethamine, or a 5-day course of pevmecillinam. High...
Source: Postgraduate Medicine - Category: Internal Medicine Tags: Postgrad Med Source Type: research
Publication date: 5 February 2020Source: Journal of Molecular Structure, Volume 1201Author(s): Mohammad Asad, Muhammad Nadeem Arshad, Salman A. Khan, Mohammad Oves, Muhammad Khalid, Abdullah M. Asiri, Ataualpa A.C. BragaAbstractThe chalcones have been cyclized into the N-propionyl-2-pyrazolines using propionic acid with hydrazine hydrate. The structures of pyrazolines were determined by FT-IR, NMR spectroscopy, and confirmed by single crystal X-ray diffraction (SC-XRD) study. Further, a combined experimental and density functional theory (DFT) based study of these pyrazolines has been reported. A comprehensive DFT investig...
Source: Journal of Molecular Structure - Category: Molecular Biology Source Type: research
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