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Analytical Biochemistry

Shahram Seidi, Mahshid Majd, Maryam Rezazadeh, Maryam Shanehsaz
A new Schiff base grafted graphene oxide-magnetic chitosan was utilized as a novel sorbent for extraction and quantification of lead ion in blood samples via dispersive magnetic solid phase extraction. The prepared nanocomposite sorbent was characterized by SEM, TEM, FT-IR, XRD, VSM and EDX and the quantification analysis was performed by microsampling flame atomic absorption spectrometry. The important parameters on the extraction efficiency were thoroughly optimized by means of experimental design. Under the optimized conditions, an aliquot of 50 mL of sample (pH 6...
May 17, 2018: Analytical Biochemistry
Maria de Fátima Alves, Ricardo Augusto Moreira de Souza Corrêa, Filipe Soares da Cruz, Diego Leoni Franco, Lucas Franco Ferreira
This paper reports the electrosynthesis and characterisation of a polymeric film derived from 2-hydroxybenzamide over a graphite electrode and its application as an enzymatic biosensor for the determination and quantification of the pesticide fenitrothion. The material was analysed by scanning electron microscopy and its electrochemical properties characterised by cyclic voltammetry and electrochemical impedance spectroscopy. The enzyme tyrosinase was immobilised over the modified electrode by the drop and dry technique...
May 16, 2018: Analytical Biochemistry
Stella Eggels, Viktoriya Avramova, Chris-Carolin Schön, Brigitte Poppenberger, Wilfried Rozhon
The plant hormone abscisic acid (ABA) regulates many processes, including response to drought, seed dormancy and abscission of leaves and fruits. For maintenance of ABA homeostasis, catabolism of ABA by 8'-hydroxylation and subsequent cyclisation to phaseic acid (PA) is crucial. However, detection of ABA 8'-hydroxylation activity is tedious. We present a simple and rapid method for detection of ABA 8'-hydroxylase activity by cloning cDNAs of interest and expressing the respective protein in yeast. Upon addition of ABA, PA is formed and subsequently quantified in the yeast cell culture supernatant by heart cutting 2D-HPLC or GC-MS...
May 16, 2018: Analytical Biochemistry
Zhanmin Liu, Chenhui Yao, Cuiyun Yang, Yanming Wang, Sibao Wan, Junyi Huang
Listeria monocytogenes is an important food-borne pathogen, and it can cause severe diseases. Rapid detection of L. monocytogenes is crucial to control this pathogen. A simple and robust strategy based on the cascade of PCR and G-quadruplex DNAzyme catalyzed reaction was used to detect L. monocytogenes. In the presence of hemin and the aptamer formed during PCR, the catalytic horseradish peroxidase-mimicking G-quadruplex DNAzymes allow the colorimetric responses of target DNA from L. monocytogenes. This assay can detect genomic DNA of L...
May 16, 2018: Analytical Biochemistry
Margaret M Elmer-Dixon, Bruce E Bowler
A novel approach to quantify mixed lipid systems is described. Traditional approaches to lipid vesicle quantification are time consuming, require large amounts of material and are destructive. We extend our recently described method for quantification of pure lipid systems to mixed lipid systems. The method only requires a UV-Vis spectrometer and does not destroy sample. Mie scattering data from absorbance measurements are used as input into a Matlab program to calculate the total vesicle concentration and the concentrations of each lipid in the mixed lipid system...
May 15, 2018: Analytical Biochemistry
Warren Lee, Syed A Ali, Leow Chiuan Yee, Tan Soo Choon, Leow Chiuan Herng
Anti-salbutamol antibodies remain as important tools for the detection of salbutamol abuse in athletic doping. This study evaluated the feasibility and efficiency of the chicken (Gallus gallus domesticus) as an immunization host to generate anti-salbutamol scFv antibodies by phage display. A phage display antibody library was constructed from a single chicken immunized against salbutamol-KLH conjugate. After a stringent biopanning strategy, a novel scFv clone which was inhibited by free salbutamol recorded the highest affinity...
May 15, 2018: Analytical Biochemistry
Nour Noaman, Jens R Coorssen
Quantitative comparative proteomics require accurate and reproducible assessments of total protein concentration. We report a straightforward, cost-effective adaptation of an established commercial method for total protein quantification, utilising non-proprietary materials and colloidal Coomassie Brilliant Blue (cCBB) staining to achieve greater reproducibility, equal sensitivity, and optimal linearity of signal within a practical concentration range for proteins in common solubilisation buffers (i.e. for isoelectric focussing and/or SDS-PAGE)...
May 12, 2018: Analytical Biochemistry
Shamima Akhter, Wan Jefrey Basirun, Yatimah Alias, Mohd Rafie Johan, Samira Bagheri, Md Shalauddin, Magaji Ladan, Nadzirah Sofia Anuar
In the present study, a nanocomposite of f-MWCNTs-chitosan-Co was prepared by the immobilization of Co(II) on f-MWCNTs-chitosan by a self-assembly method and used for the quantitative determination of paracetamol (PR). The composite was characterized by field emission scanning electron microscopy (FESEM) and energy dispersive x-ray analysis (EDX). The electroactivity of cobalt immobilized on f-MWCNTs-chitosan was assessed during the electro-oxidation of paracetamol. The prepared GCE modified f-MWCNTs/CTS-Co showed strong electrocatalytic activity towards the oxidation of PR...
May 10, 2018: Analytical Biochemistry
Cândida Dias, Cátia F Lourenço, Rui M Barbosa, João Laranjinha, Ana Ledo
The evaluation of mitochondrial function provides the basis for the study of brain bioenergetics. However, analysis of brain mitochondrial respiration has been hindered by the low yield associated with mitochondria isolation procedures. Furthermore, isolating mitochondria or cells results in loss of the inherent complexity of the central nervous system. High-resolution respirometry (HRR), is a valuable tool to study mitochondrial function and has been used in diverse biological preparations ranging from isolated mitochondria to tissue homogenates and permeabilized tissue biopsies...
May 10, 2018: Analytical Biochemistry
David R Meier, Kristopher A Lofgren, Grzegorz T Gurda, Paraic A Kenny
Unlike humans, inbred genetically engineered mice have minimal inter-individual variation and, consequently, offer substantially increased statistical power for robust definition of recurrent cooperating cancer mutations. While technically feasible, whole exome sequencing is expensive and extremely data-intensive. Somatic mutation analysis using panels of 25-75 genes now provides detailed insight into the biology of human tumors. Here we report an adaptation for mouse tumors of a human PCR amplicon-based panel (Ion Torrent Cancer Hotspot Panel v2) allowing analysis of 18 cancer genes, including Kras, Nras, Hras, Pten, Pik3ca and Smad4, and encompassing regions homologous to more than 2000 known human cancer mutations...
May 9, 2018: Analytical Biochemistry
Chengyao Ma, Yue Li, Hanqing Wu, Junyang Ji, Qianqian Sun, Yilin Song, Shen Wang, Xiang Li, Yong Chen, Jianwei Chen
Although annonaceous acetogenins (ACGs) have been reported to have antitumor activity for over three decades, and many of the underlying mechanism of ACGs on cancer have been clarified, there are still outstanding issues. In particular, the changes of small metabolite in cancer cells, caused by ACGs intake, have been reported rarely. Recent research has showed that cellular metabolic profiling coupled with ultra-flow liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UFLC-Q-TOF-MS) and multivariable statistical analysis enables a good understanding of ACGs' effects on multidrug resistant human mammary adenocarcinoma (MCF-7/Adr) cells...
May 8, 2018: Analytical Biochemistry
Benjamin R Clarkson, Rajoshi Chaudhuri, Arne Schön, Lisa Kueltzo, Ernesto Freire
Different factors affect the long term stability of monoclonal antibodies, among them denaturation or partial denaturation that is often followed by aggregation. Isothermal calorimetry is capable of quantifying the kinetics of denaturation/aggregation of an antibody by measuring the heat that is released or absorbed by the process over a period of days or weeks, at temperatures below its denaturation temperature, Tm . The denaturation/aggregation kinetics of the anti-HIV monoclonal antibody VRC07-523LS was measured by isothermal calorimetry at different concentrations in four different formulation buffers...
May 8, 2018: Analytical Biochemistry
Mahdi Ghorbani, Mahmoud Chamsaz, Mohsen Aghamohammadhasan, Alireza Shams
A simple and sensitive ultrasonic assisted magnetic dispersive solid phase microextraction method (UAMDSPME) coupled with high performance liquid chromatography was developed to determine serotonin-norepinephrine reuptake inhibitor drugs including duloxetine (DUL), venlafaxine (VEN) and atomoxetine (ATO) in human urine, river water and well water samples. A novel and efficient SPME sorbent, magnetic p-Phenylenediamine functionalized reduced graphene oxide Quantum Dots@ Ni nanocomposites (MrGOQDs-PD@ Ni), was prepared and applied for extraction of the analytes...
May 8, 2018: Analytical Biochemistry
Shannon M Prior, Kenneth G Mann, Kalev Freeman, Saulius Butenas
Hemostatic tests have been utilized to clarify the blood coagulation potential. The novel thrombin generation (TG) assay of this study provides explicit information and is the most physiologically-relevant hemostatic test ex vivo. We describe how this assay allows for TG under a number of relevant circumstances. First, whole blood (WB) from healthy individuals was analyzed ± 5 pM tissue factor (TF) and ± contact pathway inhibition. Without an exogenous initiator TG was decreased and delayed, but addition of 5 pM TF shortened the lag phase and increased peak thrombin...
May 7, 2018: Analytical Biochemistry
Gail Whiting, Jackie Ferguson, Min Fang, David Pepin, Patricia Donahoe, Paul Matejtschuk, Chris Burns, Jun X Wheeler
Measurement of serum concentrations of Müllerian inhibiting substance (MIS), also known as anti-Müllerian Hormone (AMH) by immunoassay is gaining clinical acceptance and widespread use for the diagnosis of ovarian conditions and for prediction of the response to ovarian stimulation protocols as part of assisted reproductive therapies. Provision of an International Standard to harmonize immunoassay methods is required. It is desirable for the content of a future International Standard to be assigned in mass units for consistency with the units reported by current methods...
May 6, 2018: Analytical Biochemistry
Marie K Schwinn, Trish Hoang, Xiaofeng Yang, Xiansi Zhao, Jingya Ma, Ping Li, Keith V Wood, William D Mallender, Michael E Bembenek, Zhong-Hua Yan
Neddylation is a posttranslational modification that regulates protein stability, activity, and subcellular localization. Here, we describe a new tool for exploring the neddylation cycle of cullin1 (Cul1) directly in a cellular context. This assay utilizes the NanoLuc® Binary Technology (NanoBiT) to monitor the covalent neddylation status of Cul1. A stable clonal cell line derived from HEK293 was developed that expressed a C-terminus LgBiT tagged-Cul1 and N-terminus SmBiT tagged-Nedd8. Using this cell line, we screened inhibitors that are known to disrupt Nedd8 biology and demonstrated that both inhibitors of Nedd8-activating enzyme (NAE) and Constitutive photomorphogenesis 9 signalosome (CSN) complex produce concentration and time dependent signal decreases and increases, respectively...
May 4, 2018: Analytical Biochemistry
Erik Hanff, Maximilian Zinke, Anke Böhmer, Janine Niebuhr, Mirja Maassen, Volker Endeward, Norbert Maassen, Dimitrios Tsikas
The most widely recognized activity of the large family of the metalloenzyme carbonic anhydrases (CAs) is the diffusion-controlled hydration of CO2 to HCO3 - and one proton, and the less rapid dehydration of HCO3 - to CO2 : CO2  + H2 O ⇆ HCO3 -  + H+ . CAs also catalyze the reaction of water with other electrophiles such as aromatic esters, sulfates and phosphates, thus contributing to lending to CAs esterase, sulfatase and phosphatase activity, respectively. Renal CAII and CAIV are involved in the reabsorption of nitrite, the autoxidation product of the signalling molecule nitric oxide (● NO): 4 ● NO + O2  + 2 H2 O → 4 ONO-  + 4 H+ ...
May 2, 2018: Analytical Biochemistry
Keisuke Ishigami, Hiromitsu Furukawa
This paper proposes a time-domain Gaussian-weighted noise reduction filter for bioluminescence measurement with low signal-to-noise ratio through photon counting. The filter was used for estimating the true fold-change signal from noisy gene expression data obtained through real-time dual-color luciferase assay. Furthermore, not only was the higher harmonics noise of the measurement system confirmed to reduce from the gene expression data but rapid and slow changes were also preserved in the estimated signal...
May 1, 2018: Analytical Biochemistry
Jan Vacek, Marika Svrckova, Martina Zatloukalova, David Novak, Jitka Proskova, Katerina Langova, Dana Galuszkova, Jitka Ulrichova
Human serum albumin (HSA) is a multifunctional protein with ligand binding, transporting and buffering properties. Posttranslational modifications and ligand binding processes are closely related to albumin final functional status. In the last few decades, HSA has been characterized using a broad spectrum of methods, but quantitative data on the HSA's modifications among individuals have not been reported. The investigations presented here are based on the non-denaturing electrocatalytic screening of HSA samples isolated from the blood serum of healthy subjects...
April 30, 2018: Analytical Biochemistry
Ziyue Li, Yilin Song, Guihua Xiao, Fei Gao, Shengwei Xu, Mixia Wang, Yu Zhang, Fengru Guo, Jie Liu, Yang Xia, Xinxia Cai
Temporal Lobe Epilepsy (TLE) is a chronic neurological disorder, characterized by sudden, repeated and transient central nervous system dysfunction. For better understanding of TLE, bio-nanomodified microelectrode arrays (MEA) are designed, for the achievement of high-quality simultaneous detection of glutamate signals (Glu) and multi-channel electrophysiological signals including action potentials (spikes) and local field potentials (LFPs). The MEA was fabricated by Micro-Electro-Mechanical System fabrication technology and all recording sites were modified with platinum black nano-particles, the average impedance decreased by nearly 90 times...
April 30, 2018: Analytical Biochemistry
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