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instrument, mass spectrometer, mass analyzer, mass spectrometer, mass spectrometer
This model was found at
239 locations
The model is used in
37 countries
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About the Applied Biosystems 4800

The model Applied Biosystems 4800 was found in 239 unique locations in 37 countries where it was mentioned from 2006 until recentlyIt is used by scientists in various research fields such as Biochemistry, Molecular Biology, General Medicine, General Chemistry, and Organic Chemistry. The model is also used in Molecular Medicine, Immunology, Microbiology, Cell Biology, Pharmaceutical Science, Analytical Chemistry, Drug Discovery, Pharmacology, General Biochemistry, Genetics and Molecular Biology, Spectroscopy, Biotechnology, Biophysics, Bioengineering, Physical and Theoretical Chemistry, Plant Science, Immunology and Allergy, General Physics and Astronomy, Toxicology, Microbiology (medical), Inorganic Chemistry, Structural Biology, Catalysis, Infectious Diseases, Computer Science Applications, and Genetics.
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Research that uses the Applied Biosystems 4800

Huan Cao, Ananyo Bagchi, Dimitris Tampakis, Irina Laidvee, Maria Williams, Beverley Minter, Sonja Wright, Aristotelis Antonopoulos, Stuart M. Haslam, Robert N. Barker, Mark A. Vickers, 2020
Abstract BackgroundReactive oxygen species and other free radicals, together with glucose and its metabolites are believed to play important roles in the aging process. The carbohydrate components of glycosylated proteins are important in mediating cell-cell interactions and a role has been suggested for them in the aging process. Erythrocytes are critical cells in the human body, heavily glycosylated and relatively easily available and so are good candidates to yield insights into how patterns of glycosylation change with age and disease. It has been claimed, based on a periodic acid Schiff assay, that human aging is associated with a decline of erythrocyte surface sialic acids. Plant lectins allow for more specific assays for glycans, including determining the linkage of sialic acids and analysis of single cells by flow cytometry. ResultsSialic acid specific plant lectins, Maackia amurensis lectin II (MAL), binding to α-2,3 linked sialic acids and Sambucus nigra (SNA), α-2,6 sialic acids, were used to show that erythrocyte surface sialic acids have no significant associations with donor age. A combination of storage and cellular aging produces a specific loss of α-2,6 sialic acids. By contrast, erythrocyte surface terminal fucoses increase significantly with age of donor. In order to determine which aspects of aging are important in determining this change, we investigated whether this novel human aging biomarker is associated with higher plasma glucose values, assessed by glycated hemoglobin (HbA1c) and reactive oxygen species (ROS) generation. Fucose levels were associated with HbA1c levels, but not ROS generation. ConclusionOur study identifies novel glycan-based biomarkers for human aging and disease. The simplicity of lectins are presented here as an attractive tool to study cellular medication in aging and disease.
Aadil Yousuf Tantray, Hayssam M. Ali, Altaf Ahmad, Agronomy, 10, 1028 (7), 2020
Phosphorus (P) deficiency is one of the major limiting factors for crop productivity. The yield of rice (Oryza sativa L.) is severely limited by phosphorus deficiency. An attempt has been made in this study to identify P deficiency responsive differentially expressed proteins of rice through analysis of leaf proteome of contrasting P-responsive rice cultivars under P deficiency conditions because genetic variability has been found in the rice cultivars for adaptive response to P deficiency and a controlled regulatory system is involved in the P deficiency adaptation response. Phosphorus-efficient (cv. Panvel) and P-inefficient (cv. Nagina 22) rice cultivars were hydroponically grown in the nutrient medium under control environmental conditions at low-P level (2.0 µM) and optimum-P level (320 µM) treatments. Expression patterns of the proteins of the leaves of both the cultivars were analyzed in 30-day-old plants. The identification of these proteins through mass spectrometry and MASCOT software (Matrix Science Inc., Boston, USA) revealed that these differentially expressed proteins were homologous to known functional proteins involved in energy metabolism, biosynthesis, photosynthesis, signaling, protein synthesis, protein folding, phospholipid metabolism, oxidative stress, transcription factors, and phosphorus metabolism. It has been observed that rice cultivars responded differently to low-P treatment through modification in protein expressions pattern to maintain the growth of the plants. Therefore, the expression patterns of proteins were different in both of the cultivars under low-P treatment. Higher potential of protein stability, stress tolerance, osmo-protection, and regulation of phosphorus uptake was observed in cv. Panvel than cv. Nagina 22. This study could help to unravel the complex regulatory process that is involved in adaptation to P deficiency in rice.
Xueying Zhang, Xinxin Liu, Fadi Li, Xiangpeng Yue, Animals, 10, 1784 (10), 2020
Colostrum and milk proteins are essential resources for the growth and development of the newborns, while their kinds and amounts vary greatly during the lactation period. This study was conducted to better understand whey proteome and its changes at six lactation time points (0 d, 3 d, 7 d, 14 d, 28 d, and 56 d after lambing) in Hu sheep. Using two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF/TOF MS) technologies, a total of 52 differentially expressed protein spots (DEPS), corresponding to 25 differentially expressed proteins (DEPs), were obtained. The protein spots abundance analysis revealed that the proteins are the most abundant at 0 d after lambing. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to explore the biological functions of the DEPs. The biological process was mainly involved in localization, the single-organism process, the cellular process, and a series of immune processes. The cellular components engaged in the extracellular region were the cell, organelle, and membrane. The most prevalent molecular function was binding activity. In addition, the DEPs were involved in nine significant pathways, including the Hippo signaling pathway and Complement and coagulation cascades. These results intuitively presented the changes in Hu sheep whey proteins during a 56-d lactation period, and revealed potential biological functions of the DEPs, providing a scientific basis for early weaning.
Ze Yun, Taotao Li, Huijun Gao, Hong Zhu, Vijai Kumar Gupta, Yueming Jiang, Xuewu Duan, Biomolecules, 9, 167 (5), 2019
Harvested banana ripening is a complex physiological and biochemical process, and there are existing differences in the regulation of ripening between the pulp and peel. However, the underlying molecular mechanisms governing peel ripening are still not well understood. In this study, we performed a combination of transcriptomic, proteomic, and metabolomics analysis on peel during banana fruit ripening. It was found that 5784 genes, 94 proteins, and 133 metabolites were differentially expressed or accumulated in peel during banana ripening. Those genes and proteins were linked to ripening-related processes, including transcriptional regulation, hormone signaling, cell wall modification, aroma synthesis, protein modification, and energy metabolism. The differentially expressed transcriptional factors were mainly ethylene response factor (ERF) and basic helix-loop-helix (bHLH) family members. Moreover, a great number of auxin signaling-related genes were up-regulated, and exogenous 3-indoleacetic acid (IAA) treatment accelerated banana fruit ripening and up-regulated the expression of many ripening-related genes, suggesting that auxin participates in the regulation of banana peel ripening. In addition, xyloglucan endotransglucosylase/hydrolase (XTH) family members play an important role in peel softening. Both heat shock proteins (Hsps) mediated-protein modification, and ubiqutin-protesome system-mediated protein degradation was involved in peel ripening. Furthermore, anaerobic respiration might predominate in energy metabolism in peel during banana ripening. Taken together, our study highlights a better understanding of the mechanism underlying banana peel ripening and provides a new clue for further dissection of specific gene functions.
Hyo Young Jung, Woosuk Kim, Kyu Ri Hahn, Hyun Jung Kwon, Sung Min Nam, Jin Young Chung, Yeo Sung Yoon, Dae Won Kim, Dae Young Yoo, In Koo Hwang, Cells, 9, 1067 (5), 2020
Pyridoxine, one of the vitamin B6 vitamers, plays a crucial role in amino acid metabolism and synthesis of monoamines as a cofactor. In the present study, we observed the effects of pyridoxine deficiency on novel object recognition memory. In addition, we examined the levels of 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), 3,4-dihydroxyphenethylamine (DA), 3,4-dihydroxyphenylacetic acid, and homovanillic acid and the number of proliferating cells and neuroblasts in the hippocampus. We also examined the effects of pyridoxine deficiency on protein profiles applying a proteomic study. Five-week-old mice fed pyridoxine-deficient diets for 8 weeks and showed a significant decrease in the serum and brain (cerebral cortex, hippocampus, and thalamus) levels of pyridoxal 5′-phosphate, a catalytically active form of vitamin-B6, and decline in 5-HT and DA levels in the hippocampus compared to controls fed a normal chow. In addition, pyridoxine deficiency significantly decreased Ki67-positive proliferating cells and differentiated neuroblasts in the dentate gyrus compared to controls. A proteomic study demonstrated that a total of 41 spots were increased or decreased more than two-fold. Among the detected proteins, V-type proton ATPase subunit B2 (ATP6V1B2) and heat shock cognate protein 70 (HSC70) showed coverage and matching peptide scores. Validation by Western blot analysis showed that ATP6V1B2 and HSC70 levels were significantly decreased and increased, respectively, in pyridoxine-deficient mice compared to controls. These results suggest that pyridoxine is an important element of novel object recognition memory, monoamine levels, and hippocampal neurogenesis. Pyridoxine deficiency causes cognitive impairments and reduction in 5-HT and DA levels, which may be associated with a reduction of ATP6V1B2 and elevation of HSC70 levels in the hippocampus.
Dae Young Yoo, Hyo Young Jung, Woosuk Kim, Kyu Ri Hahn, Hyun Jung Kwon, Sung Min Nam, Jin Young Chung, Yeo Sung Yoon, Dae Won Kim, In Koo Hwang, Cells, 9, 2712 (12), 2020
Entacapone, a reversible inhibitor of catechol-O-methyl transferase, is used for patients in Parkinson’s disease because it increases the bioavailability and effectiveness of levodopa. In the present study, we observed that entacapone increases novel object recognition and neuroblasts in the hippocampus. In the present study, two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry were performed to compare the abundance profiles of proteins expressed in the hippocampus after entacapone treatment in mice. Results of 2-DE, MALDI-TOF mass spectrometry, and subsequent proteomic analysis revealed an altered protein expression profile in the hippocampus after entacapone treatment. Based on proteomic analysis, 556 spots were paired during the image analysis of 2-DE gels and 76 proteins were significantly changed more than two-fold among identified proteins. Proteomic analysis indicated that treatment with entacapone induced expressional changes in proteins involved in synaptic transmission, cellular processes, cellular signaling, the regulation of cytoskeletal structure, energy metabolism, and various subcellular enzymatic reactions. In particular, entacapone significantly increased proteins related to synaptic trafficking and plasticity, such as dynamin 1, synapsin I, and Munc18-1. Immunohistochemical staining showed the localization of the proteins, and western blot confirmed the significant increases in dynamin I (203.5% of control) in the hippocampus as well as synapsin I (254.0% of control) and Munc18-1 (167.1% of control) in the synaptic vesicle fraction of hippocampus after entacapone treatment. These results suggest that entacapone can enhance hippocampal synaptic trafficking and plasticity against various neurological diseases related to hippocampal dysfunction.
Anna Serwotka-Suszczak, Alicja Sochaj-Gregorczyk, Jerzy Pieczykolan, Daniel Krowarsch, Filip Jelen, Jacek Otlewski, International Journal of Molecular Sciences, 18, 401 (2), 2017
Antibody-drug conjugates (ADCs) have recently emerged as efficient and selective cancer treatment therapeutics. Currently, alternative forms of drug carriers that can replace monoclonal antibodies are under intensive investigation. Here, a cytotoxic conjugate of an anti-HER2 (Human Epidermal Growth Factor Receptor 2) diaffibody with monomethyl-auristatin E (MMAE) is proposed as a potential anticancer therapeutic. The anti-HER2 diaffibody was based on the ZHER2:4 affibody amino acid sequence. The anti-HER2 diaffibody has been expressed as a His-tagged protein in E. coli and purified by Ni-nitrilotriacetyl (Ni-NTA) agarose chromatography. The molecule was properly folded, and the high affinity and specificity of its interaction with HER2 was confirmed by surface plasmon resonance (SPR) and flow cytometry, respectively. The (ZHER2:4)2DCS-MMAE conjugate was obtained by coupling the maleimide group linked with MMAE to cysteines, which were introduced in a drug conjugation sequence (DCS). Cytotoxicity of the conjugate was evaluated using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide MTT assay and the xCELLigence Real-Time Cell Analyzer. Our experiments demonstrated that the conjugate delivered auristatin E specifically to HER2-positive tumor cells, which finally led to their death. These results indicate that the cytotoxic diaffibody conjugate is a highly potent molecule for the treatment of various types of cancer overexpressing HER2 receptors.
Julia Chudzian, Anna Szlachcic, Malgorzata Zakrzewska, Miroslawa Czub, Marcin Pustula, Tad Holak, Jacek Otlewski, International Journal of Molecular Sciences, 19, 2470 (9), 2018
Fibroblast growth factor 1 (FGF1) and its receptors (FGFRs) regulate crucial biological processes such as cell proliferation and differentiation. Aberrant activation of FGFRs by their ligands can promote tumor growth and angiogenesis in many tumor types, including lung or breast cancer. The development of FGF1-targeting molecules with potential implications for the therapy of FGF1-driven tumors is recently being considered a promising approach in the treatment of cancer. In this study we have used phage display selection to find scFv antibody fragments selectively binding FGF1 and preventing it from binding to its receptor. Three identified scFv clones were expressed and characterized with regard to their binding to FGF1 and ability to interfere with FGF1-induced signaling cascades activation. In the next step the scFvs were cloned to scFv-Fc format, as dimeric Fc fusions prove beneficial in prospective therapeutic application. As expected, scFvs-Fc exhibited significantly increased affinity towards FGF1. We observed strong antiproliferative activity of the scFvs and scFvs-Fc in the in vitro cell models. Presented antibody fragments serve as novel FGF1 inhibitors and can be further utilized as powerful tools to use in the studies on the selective cancer therapy.
Mei-Chi Chang, Yunn-Jy Chen, Yun-Chia Lian, Bei-En Chang, Chih-Chia Huang, Wei-Ling Huang, Yu-Hwa Pan, Jiiang-Huei Jeng, International Journal of Molecular Sciences, 19, 4071 (12), 2018
Butyric acid as a histone deacetylase (HDAC) inhibitor is produced by a number of periodontal and root canal microorganisms (such as Porphyromonas, Fusobacterium, etc.). Butyric acid may affect the biological activities of periodontal/periapical cells such as osteoblasts, periodontal ligament cells, etc., and thus affect periodontal/periapical tissue destruction and healing. The purposes of this study were to study the toxic effects of butyrate on the matrix and mineralization marker expression in MG-63 osteoblasts. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cellular apoptosis and necrosis were analyzed by propidium iodide/annexin V flow cytometry. The protein and mRNA expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) were analyzed by Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). OPG, soluble RANKL (sRANKL), 8-isoprostane, pro-collagen I, matrix metalloproteinase-2 (MMP-2), osteonectin (SPARC), osteocalcin and osteopontin (OPN) secretion into culture medium were measured by enzyme-linked immunosorbant assay. Alkaline phosphatase (ALP) activity was checked by ALP staining. Histone H3 acetylation levels were evaluated by immunofluorescent staining (IF) and Western blot. We found that butyrate activated the histone H3 acetylation of MG-63 cells. Exposure of MG-63 cells to butyrate partly decreased cell viability with no marked increase in apoptosis and necrosis. Twenty-four hours of exposure to butyrate stimulated RANKL protein expression, whereas it inhibited OPG protein expression. Butyrate also inhibited the secretion of OPG in MG-63 cells, whereas the sRANKL level was below the detection limit. However, 3 days of exposure to butyrate (1 to 8 mM) or other HDAC inhibitors such as phenylbutyrate, valproic acid and trichostatin stimulated OPG secretion. Butyrate stimulated 8-isoprostane, MMP-2 and OPN secretion, but not procollagen I, or osteocalcin in MG-63 cells. Exposure to butyrate (2–4 mM) for 3 days markedly stimulated osteonectin secretion and ALP activity. In conclusion, higher concentrations of butyric acid generated by periodontal and root canal microorganisms may potentially induce bone destruction and impair bone repair by the alteration of OPG/RANKL expression/secretion, 8-isoprostane, MMP-2 and OPN secretion, and affect cell viability. However, lower concentrations of butyrate (1–4 mM) may stimulate ALP, osteonectin and OPG. These effects are possibly related to increased histone acetylation. These events are important in the pathogenesis and repair of periodontal and periapical destruction.
Shang Eun Park, Kiumars Shamloo, Timothy A. Kristedja, Shaban Darwish, Marco Bisoffi, Keykavous Parang, Rakesh Kumar Tiwari, International Journal of Molecular Sciences, 20, 3291 (13), 2019
Prostate cancer (PCa) is the most common malignancy in men and is the leading cause of cancer-related male mortality. A disulfide cyclic peptide ligand [CTVRTSADC] 1 has been previously found to target extra domain B of fibronectin (EDB-FN) in the extracellular matrix that can differentiate aggressive PCa from benign prostatic hyperplasia. We synthesized and optimized the stability of ligand 1 by amide cyclization to obtain [KTVRTSADE] 8 using Fmoc/tBu solid-phase chemistry. Optimized targeting ligand 8 was found to be stable in phosphate buffered saline (PBS, pH 6.5, 7.0, and 7.5) and under redox conditions, with a half-life longer than 8 h. Confocal microscopy studies demonstrated increased binding of ligand 8 to EDB-FN compared to ligand 1. Therefore, we hypothesized that the EDB-FN targeted peptides (1 and 8) conjugated with an anticancer drug via a hydrolyzable linker would provide selective cytotoxicity to the cancer cells. To test our hypothesis, we selected both the normal prostate cell line, RWPE-1, and the cancerous prostate cell lines, PC3, DU-145, LNCaP, and C4-2, to evaluate the anticancer activity of synthesized peptide–drug conjugates. Docetaxel (Doce) and doxorubicin (Dox) were used as anticancer drugs. Dox conjugate 13 containing disulfide linkage showed comparable cytotoxicity versus Dox after 72 h incubation in all the cancer cell lines, whereas it was found to be less cytotoxic on RWPE-1, suggesting that it can act as a Dox prodrug. Doce conjugate 14 was found to be less cytotoxic in all the cell lines as compared to drug alone.
Gabriele Clarizia, Paola Bernardo, Giuliana Gorrasi, Daniela Zampino, Sabrina Carroccio, Materials, 11, 1326 (8), 2018
Dense films based on the hydrophobic Pebax®2533 were prepared by using solution casting in different solvents as well as compression molding and subjected to photo–aging under ultraviolet (UV) irradiation. The influence of the preparation method, including the casting solvents, as well as the UV irradiation time selected to treat the samples, were evaluated in terms of permeation rates of pure gases (CO2, N2, O2, CH4, He, and H2). The transport data were correlated with the microstructure and surface properties by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), as well as water contact angle measurements. The obtained results showed that a controlled photo-oxidation process reduces the hydrophobicity of the Pebax®2533 films, increasing their permeability without compromising their integrity.
Joana Costa, Andreia Farinha, Filipe Paz, Augusto Tomé, Molecules, 24, 3177 (17), 2019
A simple and straightforward synthesis of diporphyrins and pentaporphyrins is reported here. The supramolecular interactions of the new porphyrin derivatives with C60 and PyC60 (a pyridyl [60]fulleropyrrolidine) were evaluated by absorption and fluorescence titrations in toluene. While no measurable modifications of the absorption and fluorescence spectra were observed upon addition of C60 to the porphyrin derivatives, the addition of PyC60 to the corresponding mono-Zn(II) porphyrins resulted in the formation of Zn(porphyrin)–PyC60 coordination complexes and the binding constants were calculated. Results show that the four free-base porphyrin units in pentaporphyrin 6 have a significant contribution in the stabilization of the 6–PyC60 complex. The crystal and molecular features of the pentaporphyrin Zn5 were unveiled using single-crystal X-ray diffraction studies.
Mayeli M. Martínez-Aguilar, Diana I. Aparicio-Bautista, Eric G. Ramírez-Salazar, Juan P. Reyes-Grajeda, Aldo H. De la Cruz-Montoya, Bárbara Antuna-Puente, Alberto Hidalgo-Bravo, Berenice Rivera-Paredez, Paula Ramírez-Palacios, Manuel Quiterio, Margarita Valdés-Flores, Jorge Salmerón, Rafael Velázquez-Cruz, Nutrients, 11, 2853 (12), 2019
Osteoporosis is a skeletal disease mainly affecting women over 50 years old and it represents a serious public health problem because of the high socioeconomic burden. This disease is characterized by deterioration of bone microarchitecture, low bone mineral density (BMD), and increased risk of fragility fractures. This study aimed to identify serum useful proteins as biomarkers for the diagnosis and/or prognosis of osteoporosis and fracture risk. We collected 446 serum samples from postmenopausal women aged ≥45 years old. Based on the BMD measurement, we classified the participants into three groups: osteoporotic, osteopenic, and normal. In an initial discovery stage, we conducted a proteomic approach using two-dimensional differential gel electrophoresis (2D-DIGE). The peptides into the spots of interest were identified through matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF/TOF). Enzyme-linked immunosorbent assay (ELISA) was performed to validate the proteins of interest. We identified 27 spots of interest when comparing low BMD versus normal BMD postmenopausal women. Based on their relevance in bone metabolism, we analyzed three proteins: ceruloplasmin (CP), gelsolin (GSN), and vitamin D-binding protein (VDBP). Our results demonstrated that low serum VDBP levels correlate with low BMD (osteopenic and osteoporotic). Therefore, VDBP could be considered as a novel, potential, and non-invasive biomarker for the early detection of osteoporosis.
undefined Salas-Moreno, undefined Contreras-Puentes, undefined Rodríguez-Cavallo, undefined Jorrín-Novo, undefined Marrugo-Negrete, undefined Méndez-Cuadro, Plants, 8, 513 (11), 2019
Heavy metal tolerant plants have phytoremediation potential for the recovery of contaminated soils, and the characterization of their metabolic adaptation processes is an important starting point to elucidate their tolerance mechanisms at molecular, biochemical and physiological levels. In this research, the effects of Cd and Pb on growth and protein carbonylation in tissues of Paspalum fasciculatum exposed to 30 and 50 mg·Kg-1 Cd and Pb respectively were determined. P. fasciculatum seedlings exposed to metals grew more than controls until 60 days of cultivation and limited their oxidative effects to a reduced protein group. Carbonyl indexes in leaf and root proteins reached a significant increase concerning their controls in plants exposed 30 days to Cd and 60 days to Pb. From the combined approach of Western Blot with Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and protein analysis by Matrix Asisted Laser Desorption/Ionisation - Time Of Flight (MALDI-TOF/TOF) mass spectrometry, chloroplastic proteins were identified into the main oxidative stress-inducible proteins to Cd and Pb, such as subunits α, γ of ATP synthetase, Chlorophyll CP26 binding protein, fructose-bisphosphate aldolase and long-chain ribulose bisphosphate carboxylase (RuBisCO LSU). Cd generated damage in the photosynthetic machinery of the leaves of P. fasciculatum into the first 30 days of treatment; five of the oxidized proteins are involved in photosynthesis processes. Moreover, there was a proteolytic fragmentation of the RuBisCO LSU. Results showed that intrinsic tolerance of P. fasciculatum to these metals reached 60 days in our conditions, along with the bioaccumulating appreciable quantities of metals in their roots.
undefined Gonçalves, undefined Lesport, undefined Kuylle, undefined Stura, undefined Ciolek, undefined Mourier, undefined Servent, undefined Bourinet, undefined Benoit, undefined Gilles, Toxins, 11, 484 (9), 2019
Over the two last decades, venom toxins have been explored as alternatives to opioids to treat chronic debilitating pain. At present, approximately 20 potential analgesic toxins, mainly from spider venoms, are known to inhibit with high affinity the NaV1.7 subtype of voltage-gated sodium (NaV) channels, the most promising genetically validated antinociceptive target identified so far. The present study aimed to consolidate the development of phlotoxin 1 (PhlTx1), a 34-amino acid and 3-disulfide bridge peptide of a Phlogiellus genus spider, as an antinociceptive agent by improving its affinity and selectivity for the human (h) NaV1.7 subtype. The synthetic homologue of PhlTx1 was generated and equilibrated between two conformers on reverse-phase liquid chromatography and exhibited potent analgesic effects in a mouse model of NaV1.7-mediated pain. The effects of PhlTx1 and 8 successfully synthetized alanine-substituted variants were studied (by automated whole-cell patch‐clamp electrophysiology) on cell lines stably overexpressing hNaV subtypes, as well as two cardiac targets, the hCaV1.2 and hKV11.1 subtypes of voltage-gated calcium (CaV) and potassium (KV) channels, respectively. PhlTx1 and D7A-PhlTx1 were shown to inhibit hNaV1.1–1.3 and 1.5–1.7 subtypes at hundred nanomolar concentrations, while their affinities for hNaV1.4 and 1.8, hCaV1.2 and hKV11.1 subtypes were over micromolar concentrations. Despite similar analgesic effects in the mouse model of NaV1.7-mediated pain and selectivity profiles, the affinity of D7A-PhlTx1 for the NaV1.7 subtype was at least five times higher than that of the wild-type peptide. Computational modelling was performed to deduce the 3D-structure of PhlTx1 and to suggest the amino acids involved in the efficiency of the molecule. In conclusion, the present structure–activity relationship study of PhlTx1 results in a low improved affinity of the molecule for the NaV1.7 subtype, but without any marked change in the molecule selectivity against the other studied ion channel subtypes. Further experiments are therefore necessary before considering the development of PhlTx1 or synthetic variants as antinociceptive drug candidates.
Sira Defaus, Mar Forner, Rodrigo Cañas-Arranz, Patricia de León, María J. Bustos, Miguel Rodríguez-Pulido, Esther Blanco, Francisco Sobrino, David Andreu, Vaccines, 8, 406 (3), 2020
A broadly protective and biosafe vaccine against foot-and-mouth disease virus (FMDV) remains an unmet need in the animal health sector. We have previously reported solid protection against serotype O FMDV afforded by dendrimeric peptide structures harboring virus-specific B- and T-cell epitopes, and also shown such type of multivalent presentations to be advantageous over simple B-T-epitope linear juxtaposition. Chemically, our vaccine platforms are modular constructions readily made from specified B- and T-cell epitope precursor peptides that are conjugated in solution. With the aim of developing an improved version of our formulations to be used for on-demand vaccine applications, we evaluate in this study a novel design for epitope presentation to the immune system based on a multiple antigen peptide (MAP) containing six immunologically relevant motifs arranged in dendrimeric fashion (named B2T-TB2). Interestingly, two B2T units fused tail-to-tail into a single homodimer platform elicited higher B- and T-cell specific responses than former candidates, with immunization scores remaining stable even after 4 months. Moreover, this macromolecular assembly shows consistent immune response in swine, the natural FMDV host, at reduced dose. Thus, our versatile, immunogenic prototype can find application in the development of peptide-based vaccine candidates for various therapeutic uses using safer and more efficacious vaccination regimens.
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