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Analytical Biochemistry

Shwu-Maan Lee, Jordan Plieskatt, C Richter King
A liquid chromatography tandem-mass spectrometry method was developed to map the eleven disulfide bonds in Pfs25, a malaria transmission-blocking vaccine candidate. The compact and complex nature of Pfs25 has led to difficulties in prior peptide mapping efforts. Here, we report confirmation of proper disulfide pairing of a recombinant Pfs25, by optimizing denaturation and digestion with trypsin/Lys-C. The digested peptides were separated by reversed phase HPLC to obtain the peptide map and elucidate the disulfide linkages...
November 18, 2017: Analytical Biochemistry
Lara A B C Carneiro, Richard J Ward
A paramagnetic nanocomposite coated with chitosan and N-(5-Amino-1-carboxy-pentyl) iminodiacetic acid (NTA) that is suitable for protein immobilization applications has been prepared and characterized. The nanoparticle core was synthesized by controlled aggregation of Fe3O4 under alkaline conditions, and Transmission Electron Microscopy revealed a size distribution of 10-50 nm. The nanoparticle core was coated with chitosan and derivatized with glutaraldehyde and NTA, as confirmed by Fourier Transform Infrared Spectroscopy...
November 18, 2017: Analytical Biochemistry
Bo Pang, Chao Zhao, Li Li, Xiuling Song, Kun Xu, Juan Wang, Yushen Liu, Kaiyue Fu, Hao Bao, Dandan Song, Xiangjun Meng, Xiaofeng Qu, Zhuping Zhang, Juan Li
Escherichia coli O157: H7 (E. coli O157: H7) has become one of the most dangerous foodborne pathogenic bacteria around the world. Currently, because of the tedious, high-cost and stringent laboratory conditions required, the conventional E. coli O157: H7 detection methods, such as culture-based methods and polymerase chain reaction (PCR), have much limitation. Thus, we developed a novel paper-based enzyme-linked immunosorbent assay (p-ELISA) with shorter operation duration, lower cost, relatively higher sensitivity and wider application...
November 17, 2017: Analytical Biochemistry
Damien Hall, Akira Kinjo, Yuji Goto
We re-examine a site-binding approach independently proposed by Schellman (Schellman, J.A. (1958) Compt. rend. Lab. Carlsberg Ser. Chim. 30, 439-449) and Aune and Tanford (Aune, K.C. and Tanford, D. (1969) Biochemistry, 8, 4586-4590) for explicitly including the denaturant concentration within the protein unfolding equilibrium. We extend and formalize the approach through development of a multi-dimensional analytical model in which the folding reaction coordinate is defined by the number of denaturant molecules bound to sites located on either the initially folded, or unfolded, states of the protein...
November 17, 2017: Analytical Biochemistry
M V Berridge, P M Herst, M R Rowe, R Schneider, M J McConnell
Interest in the recently discovered phenomenon of mitochondrial transfer between mammalian cells has gained momentum since it was first described in cell culture systems more than a decade ago. Mitochondria-targeting fluorescent dyes have been repurposed and are now widely used in these studies and in acute disease models, sometimes without due consideration of their limitations, while vectors containing mitochondrially-imported fluorescent proteins have complemented the use of mitochondria-targeting dyes. Genetic approaches that use mitochondrial DNA polymorphisms have also been used in some in vitro studies and in tumor models and are particularly useful where mtDNA is damaged or deleted...
November 17, 2017: Analytical Biochemistry
Zihni Onur Uygun, Çağdaş Şahin, Merve Yilmaz, Yasemin Akçay, Ali Akdemir, Ferhan Sağin
The aim of this study is to develop a nanomaterial-dendrimer composite modified biosensor to detect Fetuin-A (HFA) in real blood samples. For this purpose, we designed an Electrochemical Impedance Spectroscopy (EIS) based anti-Fetuin-A (Anti-HFA) modified biosensor system and tested in real blood samples. Chronoimpedance was also employed. The same samples were analyzed with ELISA and the results were compared for validation of the new system. Gold screen printed electrodes (AuSPE) were used as transducer. Firstly, a self-assembly monolayer (SAM) was formed on gold surface by 4-aminothiophenol (4-ATP), Fullerene and PAMAM-NH2 (G5), layers were formed, consecutively...
November 17, 2017: Analytical Biochemistry
Rosita Russo, Giuseppina Focà, Camilla Rega, Annamaria Sandomenico, Nunzianna Doti, Filippo Mori, Marcella Maddaluno, Claudio Farina, Menotti Ruvo, Angela Chambery
Plasma-derived proteins are a subset of relevant biotherapeutics also known as "well-characterized biologicals". They are enriched from plasma through several steps of physical and biochemical methodologies, reaching the regulatory accepted standards of safety, levels of impurities, activity and lot-to-lot consistency. Final products accepted for commercialization are submitted to tight analytical, functional and safety controls by a number of different approaches that fulfill the requirements of sensitivity and reliability...
November 14, 2017: Analytical Biochemistry
Sergey Nikolaev, Laure Lemmens, Thibaud Koessler, Jean-Louis Blouin, Thierry Nouspikel
We present the results of our technical validation process in establishing the analysis of circulating tumor DNA (ctDNA) as a diagnostic tool. Like most cells in our body, tumor cells shed DNA in the blood flow. Analysis of ctDNA mutational content can provide invaluable information on the genetic makeup of a tumor, and assist oncologists in deciding on therapy, or in following residual disease. However, low absolute amounts of circulating DNA and low tumor fraction constitute formidable analytical challenges...
November 11, 2017: Analytical Biochemistry
Yan Chen, Ying Zhao, Yan-Bo Li, Yan-Jun Wang, Gui-Zhen Zhang
OBJECTIVE: To establish a high throughput, low cost, and simple nanotechnology-based method for the detection of single nucleotide polymorphism (SNP) loci in type 2 diabetes mellitus (T2DM). METHODS: Multiplex ligase detection reaction (LDR) amplification was performed using fluorescently labeled magnetic nanosphere-bound upstream LDR probes and downstream probes labeled with a unique fluorescent group for each SNP locus. The amplified LDR products were separated by magnetic nanospheres and then scanned by fluorescence spectroscopy...
November 9, 2017: Analytical Biochemistry
Noriko Iwamoto, Akinobu Hamada, Takashi Shimada
Therapeutic monoclonal antibodies (mAbs) are developed for treatment of diverse cancers and autoimmune diseases. For expansion of mAbs approval against unapproved diseases and pharmaceutical development, pharmacokinetics study is very important. Bioanalysis provides one of the most essential index against pharmacokinetics information. So far, we developed useful method for bioanalysis of mAbs in plasma or serum, nSMOL: nano-surface and molecular-orientation limited proteolysis. This method can provide accurate and reproducible value of mAbs content in plasma...
November 9, 2017: Analytical Biochemistry
Catpagavalli Asokanathan, Sharon Tierney, Christina R Ball, George Buckle, Ami Day, Simon Tanley, Adrian Bristow, Kevin Markey, Dorothy Xing, Chun-Ting Yuen
ADP-ribosyltransferase activities have been observed in many prokaryotic and eukaryotic species and viruses and are involved in many cellular processes, including cell signalling, DNA repair, gene regulation and apoptosis. In a number of bacterial toxins, mono ADP-ribosyltransferase is the main cause of host cell cytotoxicity. Several approaches have been used to analyse this biological system from measuring its enzyme products to its functions. By using a mono ADP-ribose binding protein we have now developed an ELISA method to estimate native pertussis toxin mono ADP-ribosyltransferase activity and its residual activities in pertussis vaccines as an example...
November 8, 2017: Analytical Biochemistry
Beáta Bozóki, Lívia Gazda, Ferenc Tóth, Márió Miczi, János András Mótyán, József Tőzsér
In connection with the intensive investigation of proteases, several methods have been developed for analysis of the substrate specificity. Due to the great number of proteases and the expected target molecules to be analyzed, time- and cost-efficient high-throughput screening (HTS) methods are preferred. Here we describe the development and application of a separation-based HTS-compatible fluorescent protease assay, which is based on the use of recombinant fusion proteins as substrates of proteases. The protein substrates used in this assay consists of N-terminal (hexahistidine and maltose binding protein) fusion tags, cleavage sequences of the tobacco etch virus (TEV) and HIV-1 proteases, and a C-terminal fluorescent protein (mApple or mTurquoise2)...
November 6, 2017: Analytical Biochemistry
Qi Zhang, Xiaoyan Li, Chunhua Qian, Li Dou, Feng Cui, Xiaojun Chen
The content of neuron specific enolase (NSE) in serum is considered to be an essential indicator of small cell lung cancer (SCLC). Here, a novel label-free electrochemical immunoassay for the detection of NSE based on the three dimensionally macroporous reduced graphene oxide/polyaniline (3DM rGO/PANI) film has been proposed. The 3DM rGO/PANI film was constructed by electrochemical co-deposition of GO and aniline into the interspaces of a sacrificial silica opal template modified Au slice. During the co-deposition, GO was successfully reduced by aniline and PANI could be deposited on the surfaces of rGO sheets...
November 4, 2017: Analytical Biochemistry
Julia Hennicke, Anna Maria Lastin, David Reinhart, Clemens Grünwald-Gruber, Friedrich Altmann, Renate Kunert
Immunoglobulin M (IgM) antibodies are reckoned as promising tools for therapy and diagnostic approaches. Nevertheless, the commercial success of IgMs is hampered due to bottlenecks in recombinant production and downstream processing. IgMs are large, complex and highly glycosylated proteins that are only stable in a limited range of conditions. To investigate these sensitive IgM antibodies we optimized the elution conditions for a commercially available IgM affinity matrix (CaptureSelect™). Applying a small-scale screening system, we optimized our single step purification strategy for high purity, high yield and retained antigen binding capacity...
November 4, 2017: Analytical Biochemistry
Torben Larsen
OBJECTIVE: D-lactic acid in the mammalian body is mainly of microbiological origin and is often located somewhere along the digestive tract. Surgical, extensive re-sectioning of the small bowel may be one of the risk factors for altered balance in the microbiological environment. Higher levels in the body may lead to D-lactate acidosis and neurotoxicity; consequently, the possibility of diagnosis of this condition is important. Several analytical procedures for D-lactate have been introduced, but it is absolutely mandatory to distinguish this metabolite from the much more abundant and naturally occurring stereoisomer L-lactate...
November 3, 2017: Analytical Biochemistry
Tasha B Toro, Samantha A Edenfield, Brandon J Hylton, Terry J Watt
Acetylation is an important regulatory mechanism in cells, and emphasis is being placed on identifying substrates and small molecule modulators of this post-translational modification. However, the reported in vitro activity of the lysine deacetylase KDAC8 is inconsistent across experimental setups, even with the same substrate, complicating progress in the field. We detected trace levels of zinc, a known inhibitor of KDAC8 when present in excess, even in high-quality buffer reagents, at concentrations that are sufficient to significantly inhibit the enzyme under common reaction conditions...
October 31, 2017: Analytical Biochemistry
Jia-Jia Yang, Zhi-Feng Zhang, Gui-Qin Yan
MicroRNAs (miRNAs) play an important role in many biological processes, and its level in plasma and other biological fluids is closely related to many diseases. In this work, a selective room-temperature phosphorescence (RTP) detection method for miRNA was developed based on a duplex-specific nuclease (DSN) -assisted signal amplification strategy and phosphorescence resonance energy transfer (PRET) between poly-diallyldimethylammonium chloride-modified quantum dots (QDs@PDDA) and 6-carboxy-X-rhodamine-modified miRNA sequences complementary oligonucleotide (ROX-ssDNA)...
October 28, 2017: Analytical Biochemistry
J E Abud, C G Santamaría, E H Luque, H A Rodriguez
In the present study, we developed both a conventional enzyme-linked immunosorbent assay (ELISA) and a highly sensitive immuno-polymerase chain reaction (IPCR) assay specific for detection of human thyroid stimulating hormone (hTSH). Several anti-hTSH monoclonal antibodies (MAbs) were generated using hybridoma technology. Two pairs of MAbs (B-4 and B-9) were rationally selected and the optimal assay conditions of sandwich ELISAs were established. The ELISA prototypes were evaluated with standards calibrated with WHO 2nd International Reference Preparation for hTSH and in comparison with a commercial ELISA Kit...
October 27, 2017: Analytical Biochemistry
Jennifer C Thera, Karen A Kidd, M Elaine Dodge-Lynch, Robert F Bertolo
We examined the performance of an ultra-high performance liquid chromatography method to quantify protein-bound sulphur amino acids in zooplankton. Both cysteic acid and methionine sulfone were linear from 5 to 250 pmol (r(2) = 0.99), with a method detection limit of 13 pmol and 9 pmol, respectively. Although there was no matrix effect on linearity, adjacent peaks and co-eluting noise from the invertebrate proteins increased the detection limits when compared to common standards. Overall, performance characteristics were reproducible and accurate, and provide a means for quantifying sulphur amino acids in aquatic invertebrates, an understudied group...
October 26, 2017: Analytical Biochemistry
Koji Hashimoto, Mika Inada, Keiko Ito
We have developed a novel voltammetric DNA chip for real-time electrochemical detection of targeted nucleic acid sequences using loop-mediated isothermal amplification (LAMP) and ruthenium hexaamine (RuHex) as the intercalative redox compound. A GspSSD DNA polymerase was used for LAMP owing to its tolerance of the intercalative redox compound. The electrochemical reaction of 1 mM RuHex in the LAMP solution was measured continuously by linear sweep voltammetry at 65 °C using an electrochemical DNA chip. According to the LAMP reaction of the positive sample, the cathodic peak current of RuHex increased and the cathodic peak potential of RuHex shifted to negative voltage...
October 24, 2017: Analytical Biochemistry
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