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1
XIN, HUA-MEI, and YUEMIN ZHU. "ACCURATE NONLINEAR REGISTRATION FOR TWO-DIMENSIONAL GEL ELECTROPHORESIS IMAGES." Journal of Biological Systems 21, no. 03 (September 2013): 1350020. http://dx.doi.org/10.1142/s0218339013500204.
Повний текст джерелаАнотація:
Two-dimensional gel electrophoresis (2DGE) images are an important support for the analysis of proteins in proteomics. The registration of 2DGE images is considered as one of key elements in protein identification while it is a difficult problem. This paper proposes a new accurate nonlinear registration approach for 2DGE images, based on the exploitation of both spot distance measure and spot intensity. The method consists of three steps: multi-resolution affine registration, spot pairing and thin-plate spline interpolation. The results on both simulated and real gel images show that the proposed method significantly improves registration accuracy in comparison with thin-plate spline registration techniques.
2
Villegas-Rivera, Gerardo Antonio, Maria C. Torres-Madronero, Sarah Rothlisberger Booth, and Edilson Delgado Trejos. "Procesamiento de imágenes de electroforesis bidimensional: una revisión." Scientia et technica 24, no. 1 (March 30, 2019): 76. http://dx.doi.org/10.22517/23447214.20091.
Повний текст джерелаАнотація:
Este artículo presenta una revisión de las técnicas y algoritmos aplicados al procesamiento y análisisde imágenes de electroforesis bidimensional (2DGE). La electroforesis bidimensional permite separar cientos de proteínas en un único gel, mostrando un patrón característico. En el análisis de imágenes es importante una correcta detección de las proteínas presentes, ya que cualquier error en esta etapa puede llevar a la detección de falsas proteínas, o a obviar proteínas importantes, pero de baja abundancia, lo cual afectaría los resultados del análisis. Técnicas de segmentación son empleadas para separar las proteínas del fondo y encontrar anomalías. Los métodos empleados para la segmentación de imágenes 2DGE se pueden clasificar como: basados en detección de bordes, morfológicos, umbralización y basados en regiones. En muchos estudios proteómicos se hace necesario la fusión o registro de imágenes para la identificación y comparación de patrones de varias muestras diferentes. Para este proceso de fusión se pueden usar las imágenes originales o los resultados de la segmentación. A pesar de los avances significativos en el campo de procesamiento de imágenes 2DGE, no se encuentran en la literatura métodos completamente automatizados. Las herramientas comerciales disponibles para el análisis y procesamiento de imágenes 2DGE requieren que el usuario seleccione adecuadamente ciertos parámetros, de los cuales dependen los resultados arrojados por el software. Este artículo revisa diferentes técnicas para el procesamiento de las imágenes 2DGE. Especial atención es dada a las técnicas de segmentación y registro de imágenes.
3
Wang, Li, and Nanbert Zhong. "Application of the ProteomeLab™ PF2D protein fractionation system in proteomic analysis for human genetic diseases." Open Chemistry 10, no. 3 (June 1, 2012): 836–43. http://dx.doi.org/10.2478/s11532-012-0033-2.
Повний текст джерелаАнотація:
AbstractProteomic analysis has been widely used in elucidating the mechanism of diseases. As a classical proteomic approach, two-dimensional gel electrophoresis (2DGE) has been commonly applied in finding differentially expressed proteins through a first dimension of separation by the isoelectric point (pI) of proteins and a second dimension of separation according to the molecular weight (MW) of proteins. Compared to 2DGE, a recently developed commercial system from Beckman Coulter, the two-dimensional protein fractionation (PF2D), separates proteins according to the pI of proteins in the first dimension followed by a second dimension of separation according to the degree of protein hydrophobicity. As a liquid-based fractionation system, PF2D could facilitate the extraction and separation of broader protein categories and improve reproducibility and quantification as well as be less labor-intensive, which are usually identified as limitations of a gel-based 2DGE platform. This review evaluates the applications of the PF2D system and discusses the perspectives and advantages of PF2D in the investigation of cancer and genetic disorders and in protein mapping in human biological fluids and cell cultures.
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Osbun, Joshua, Philip Tatman, Sumanpreet Kaur, Carolina Parada, Tina Busald, Luis Gonzalez-Cuyar, Min Shi, Donald Born, Jing Zhang, and Manuel Ferreira. "Comparative Proteomic Profiling Using Two-Dimensional Gel Electrophoresis and Identification via LC-MS/MS Reveals Novel Protein Biomarkers to Identify Aggressive Subtypes of WHO Grade I Meningioma." Journal of Neurological Surgery Part B: Skull Base 78, no. 05 (April 26, 2017): 371–79. http://dx.doi.org/10.1055/s-0037-1601889.
Повний текст джерелаАнотація:
Background Meningomas represent the most common primary intracranial tumor. The majority are benign World Health Organization (WHO) Grade I lesions, but a subset of these behave in an aggressive manner. Protein biomarkers are needed to distinguish aggressive from benign Grade I lesions. Materials and Methods Pooled protein lysates were derived from five clinically aggressive Grade I and five typically benign WHO Grade I tumors snap frozen at the time of surgery. Proteins were separated in each group using two-dimensional gel electrophoresis (2DGE) and protein spots of interest were identified using liquid chromatography–mass spectrometry (LC-MS). Potential biomarker candidates were validated using western blot assays in individual tumor samples and by tissue microarray (TMA). Results Seven candidate biomarkers were obtained from the 2DGE and validated via western blot and TMA. Biomarker validation data allowed for the creation of predictive models using binary logistical regression that correctly identified 85.9% of aggressive tumors within the larger cohort of Grade I meningioma. Conclusion Simple protein separation by 2DGE and identification of candidate biomarkers by LC-MS allowed for the identification of seven candidate biomarkers that when used in predictive models accurately distinguish aggressive from benign behavior in WHO Grade I meningioma.
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Urrea, Juan E., Luisa F. Restrepo, Jeanette Prada-Arismendy, Erwing Castillo, Manuel M. Goez, Maria C. Torres-Madronero, Edilson Delgado-Trejos, and Sarah Röthlisberger. "Dataset of Two-Dimensional Gel Electrophoresis Images of Acute Myeloid Leukemia Patients before and after Induction Therapy." Data 6, no. 2 (February 18, 2021): 20. http://dx.doi.org/10.3390/data6020020.
Повний текст джерелаАнотація:
Acute myeloid leukemia (AML) is a malignant disorder of the hematopoietic stem and progenitor cells, which results in the build-up of immature blasts in the bone marrow and eventually in the peripheral blood of affected patients. Accurately assessing a patient´s prognosis is very important for clinical management of the disease, which is why there are several prognostic factors such as age, performance status at diagnosis, platelet count, serum creatinine and albumin that are taken into account by the clinician when deciding the course of treatment. However, proteomic changes related to treatment response in this patient group have not been widely explored. Here, we make available a set of 22 two-dimensional gel electrophoresis (2DGE) images obtained from the peripheral blood samples of 11 patients with AML, taken at the time of diagnosis and after induction therapy (approximately 21–28 days after starting treatment). The same set of 2DGE images is also made available after a preprocessing stage (an additional 22 2DGE pre-processed images), which was performed using algorithms developed in Python, in order to improve the visualization of characteristic spots and facilitate proteomic analysis of this type of images.
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Zhan, Xianquan, and Dominic M. Desiderio. "Heterogeneity Analysis of the Human Pituitary Proteome." Clinical Chemistry 49, no. 10 (October 1, 2003): 1740–51. http://dx.doi.org/10.1373/49.10.1740.
Повний текст джерелаАнотація:
Abstract Background: A human proteome is relatively dynamic compared with its corresponding genome. Our aim was to study the heterogeneity of a human pituitary proteome as a function of gender, age, and race. Methods: Pituitary control tissues (n = 8) were used to extract proteins; each control tissue was analyzed (n = 3–5) with two-dimensional gel electrophoresis (2DGE) and PDQuest software. We obtained 30 high-resolution 2DGE gels and conducted a comparative analysis as a function of gender, age, and race. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry and liquid chromatography-electrospray ionization-quadrupole-ion trap tandem mass spectrometry were used to characterize the protein in each differential spot. Results: We detected ∼1000 protein spots in each 2DGE map, and 51 differential spots (7 differing with gender, 17 with age, 15 with race, and 12 with the coeffect of age and race). Among those 51, we characterized 28 proteins [5 differing with gender, 8 with age, 6 with race, 8 with the coeffect of age and race, and 1 (somatotropin chain 1) with all of these]. Somatotropin was related to gender, age, and race, and prolactin was higher in females than males. The differentially expressed proteins that were related to age were mainly those proteins associated with cell growth, proliferation, differentiation, apoptosis, and death; those proteins showed no difference with gender and race. Age and race affected some proteins associated with hormone regulation (e.g., follistatin, thyroid hormone receptor β-2, adenylate cyclase-inhibiting Gα protein). Conclusions: A heterogeneity exists in the human pituitary proteome as a function of gender, age, and race. These findings will serve as a basis for our comparative proteomics studies of human pituitary adenomas.
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Balgir, P. P., S. S. Shishkin, P. S. Gromoy, and Y. Kornienko. "Human chorionic villi development through gestation: Studied by 2DGE." Cell Differentiation and Development 27 (August 1989): 142. http://dx.doi.org/10.1016/0922-3371(89)90434-6.
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Aizat, Wan M., Jason A. Able, James C. R. Stangoulis, and Amanda J. Able. "Proteomic analysis during capsicum ripening reveals differential expression of ACC oxidase isoform 4 and other candidates." Functional Plant Biology 40, no. 11 (2013): 1115. http://dx.doi.org/10.1071/fp12330.
Повний текст джерелаАнотація:
Capsicum (Capsicum annuum L.) is categorised as a non-climacteric fruit that exhibits limited ethylene production during ripening and the molecular mechanisms associated with this process are poorly understood. A proteomic approach was used to identify the differentially expressed proteins during various ripening stages (Green (G), Breaker Red 1 (BR1) and Light Red (LR)) and the genes associated with their synthesis. From 2D gel electrophoresis (2DGE), seven protein spots were identified as selectively present either in G or BR1 and are involved in carbon metabolism, colour and fruit development, protein synthesis and chaperones or biosynthesis of amino acids and polyamines. One candidate of interest, 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACO) is known to be involved in ethylene biosynthesis and was only present in BR1 and is related to the tomato ACO isoform 4 (LeACO4) and hence named CaACO4. CaACO4 RNA expression as well as total ACO protein expression in multiple stages of ripening (G, Breaker (B), BR1, Breaker Red 2 (BR2), LR and Deep Red (DR)) corresponded to the 2DGE protein spot abundance in breaker stages. Our findings highlight the involvement of the ethylene pathway in non-climacteric fruit ripening.
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Guo, Tianyao, Xiaowei Wang, Maoyu Li, Haiyan Yang, Ling Li, Fang Peng, and Xianquan Zhan. "Identification of Glioblastoma Phosphotyrosine-Containing Proteins with Two-Dimensional Western Blotting and Tandem Mass Spectrometry." BioMed Research International 2015 (2015): 1–21. http://dx.doi.org/10.1155/2015/134050.
Повний текст джерелаАнотація:
To investigate the presence of, and the potential biological roles of, protein tyrosine phosphorylation in the glioblastoma pathogenesis, two-dimensional gel electrophoresis- (2DGE-) based Western blotting coupled with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis was used to detect and identify the phosphotyrosine immunoreaction-positive proteins in a glioblastoma tissue. MS/MS and Mascot analyses were used to determine the phosphotyrosine sites of each phosphopeptide. Protein domain and motif analysis and systems pathway analysis were used to determine the protein domains/motifs that contained phosphotyrosine residue and signal pathway networks to clarify the potential biological functions of protein tyrosine phosphorylation. A total of 24 phosphotyrosine-containing proteins were identified. Each phosphotyrosine-containing protein contained at least one tyrosine kinase phosphorylation motif and a certain structural and functional domains. Those phosphotyrosine-containing proteins were involved in the multiple signal pathway systems such as oxidative stress, stress response, and cell migration. Those data show 2DGE-based Western blotting, MS/MS, and bioinformatics are a set of effective approaches to detect and identify glioblastoma tyrosine-phosphorylated proteome and to effectively rationalize the biological roles of tyrosine phosphorylation in the glioblastoma biological systems. It provides novel insights regarding tyrosine phosphorylation and its potential role in the molecular mechanism of a glioblastoma.
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Khoo, Kelvin H. P., Amanda J. Able, Timothy K. Chataway, and Jason A. Able. "Preliminary characterisation of two early meiotic wheat proteins after identification through 2D gel electrophoresis proteomics." Functional Plant Biology 39, no. 3 (2012): 222. http://dx.doi.org/10.1071/fp11253.
Повний текст джерелаАнотація:
Various genetic-based approaches including mutant population screens, microarray analyses, cloning and transgenesis have broadened our knowledge of gene function during meiosis in plants. Nonetheless, these genetic tools are not without inherent limitations. One alternative approach to studying plant meiosis, especially in polyploids such as Triticum aestivum L. (bread wheat), is proteomics. However, protein-based approaches using proteomics have seldom been described, with only two attempts at studying early plant meiosis reported. Here, we report the investigation of early bread wheat meiosis using proteomics. Five differentially expressed protein spots were identified using 2D gel electrophoresis (2DGE) on protein extracts from four pooled stages of meiosis and three genotypes (Chinese Spring wild-type, ph1b and ph2a wheat mutant lines). Tandem mass spectrometry (MS/MS) identification of peptides from these protein spots led to the isolation and characterisation of the full-length clones of a wheat Speckle-type POZ protein, an SF21-like protein and HSP70, and a partial coding sequence of a hexose transporter. Significantly, the putative functions of the Speckle-type POZ protein and HSP70 were confirmed using in vitro DNA binding assays. Through the use of a 2DGE proteomics approach, we show that proteomics is a viable alternative to genetic-based approaches when studying meiosis in wheat. More significantly, we report a potential role for a Speckle-type POZ protein and a HSP70 in chromosome pairing during the early stages of meiosis in bread wheat.
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Amacher, David E., Rick Adler, Athula Herath, and R. Reid Townsend. "Use of Proteomic Methods to Identify Serum Biomarkers Associated with Rat Liver Toxicity or Hypertrophy." Clinical Chemistry 51, no. 10 (October 1, 2005): 1796–803. http://dx.doi.org/10.1373/clinchem.2005.049908.
Повний текст джерелаАнотація:
Abstract Background: Our objectives were to identify serum marker proteins in rats that might serve as sensitive indicators of hepatomegaly, hepatocellular necrosis, or hepatobiliary injury and to use them to analyze data from a collaborative proteomics project. Methods: In each of 4 studies comprising the collaborative project, rats were given 1 of 4 compounds that target the liver through different mechanisms. Sera and liver samples were collected by terminal bleeds at 1 of 3 postdose time points. Sera were depleted of major secretory proteins and then separated into protein features by 2-dimensional gel electrophoresis (2DGE). Liver specimens were also processed and subjected to 2DGE. Protein spots that significantly increased or decreased in quantity after drug treatment were recovered, digested, analyzed by mass spectroscopy, and compared with available databases for identification. Criteria for further consideration were (a) temporal expression (i.e., increase or decrease at early, fulminant, or recovery periods), (b) known biological function, (c) probable hepatic origin, and (d) any previous association with toxicity in published studies. Markers that changed significantly at the early time point were important because of their potential sensitivity for signaling minimal damage. Results: Vitamin D–binding protein, paraoxonase, cellular retinol-binding protein, malate dehydrogenase, F-protein, and purine nucleoside phosphorylase were identified as empirically confirmed serum markers for hepatic effects in drug-treated rats. Conclusion: Proteomics can be applied for the identification and confirmation of peripheral biomarkers for altered liver function after toxicant exposure.
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Chen, J., T.-S. Chen, C. Lin, S.-Y. Chen, and J. Lin. "A simple JPEG-LS compressed technique for 2DGE image with ROI emphasis." Imaging Science Journal 63, no. 2 (September 10, 2014): 76–80. http://dx.doi.org/10.1179/1743131x14y.0000000086.
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Jaleel, Abdul, and K. Sreekumaran Nair. "Identification of multiple proteins whose synthetic rates are enhanced by high amino acid levels in rat hepatocytes." American Journal of Physiology-Endocrinology and Metabolism 286, no. 6 (June 2004): E950—E957. http://dx.doi.org/10.1152/ajpendo.00403.2003.
Повний текст джерелаАнотація:
Amino acids are key regulators of protein synthesis in liver. However, it remains to be determined whether amino acids stimulate synthesis of all or certain specific liver proteins. No techniques are currently available to simultaneously measure synthetic rates of several individual proteins. Here we report studies performed on rat hepatocyte primary cultures in which we used metabolic labeling with [14C]leucine, two-dimensional gel electrophoresis (2DGE), and tandem mass spectrometry to identify proteins that showed increased leucine incorporation when high amino acid levels were present in the media. Rat hepatocytes were isolated by in situ collagenase perfusion, cultured in serum-free medium containing insulin, and incubated for 2, 4, and 8 h in media of standard and high amino acid concentrations. SDS-PAGE and 2DGE were performed to separate proteins from cell lysates. Proteins that consistently showed increased synthesis on triplicate cultures, as detected by phosphorimaging of gels, were identified by tandom mass spectrometry. The combination of these approaches enabled the detection of 16 specific liver proteins whose synthetic rates were enhanced by increased amino acid concentration. These proteins are involved in specific functions such as translation intiation, protein folding and modification, oxidative phosphorylation, antioxidant defense, signal transduction, and transport, as well as cell motility and tissue integrity. No quantitative changes for any of these proteins were detected by gel staining, indicating that no detectable changes in protein concentration occurred. In contrast, measurable changes in synthetic rates occurred in 16 proteins. In conclusion, amino acids stimulate the synthesis of several liver proteins with important cellular functions.
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Lin, Jen-Jie, Chun-Chieh Huang, Yu-Li Su, Hao-Lun Luo, Nai-Lun Lee, Ming-Tse Sung, and Yu-Jen Wu. "Proteomics Analysis of Tangeretin-Induced Apoptosis through Mitochondrial Dysfunction in Bladder Cancer Cells." International Journal of Molecular Sciences 20, no. 5 (February 26, 2019): 1017. http://dx.doi.org/10.3390/ijms20051017.
Повний текст джерелаАнотація:
Tangeretin is one of the most abundant compounds in citrus peel, and studies have shown that it possesses anti-oxidant and anti-cancer properties. However, no study has been conducted on bladder cancer cells. Bladder cancer has the second highest mortality rate among urological cancers and is the fifth most common malignancy in the world. Currently, combination chemotherapy is the most common approach by which to treat patients with bladder cancer, and thus identifying more effective chemotherapeutic agents that can be safely administered to patients is a very important research issue. Therefore, this study investigated whether tangeretin can induce apoptosis and identified the signaling pathways of tangeretin-induced apoptosis in human bladder cancer cells using two-dimensional gel electrophoresis (2DGE). The results of the study demonstrated that 60 μM tangeretin reduced the cell survival of a BFTC-905 bladder carcinoma cell line by 42%, and induced early and late apoptosis in the cells. In this study 2DGE proteomics technology identified 41 proteins that were differentially-expressed in tangeretin-treated cells, and subsequently LC–MS/MS analysis was performed to identify the proteins. Based on the functions of the differentially-expressed proteins, the results suggested that tangeretin caused mitochondrial dysfunction and further induced apoptosis in bladder cancer cells. Moreover, western blotting analysis demonstrated that tangeretin treatment disturbed calcium homeostasis in the mitochondria, triggered cytochrome C release, and activated caspase-3 and caspase-9, which led to apoptosis. In conclusion, our results showed that tangeretin-induced apoptosis in human bladder cancer cells is mediated by mitochondrial inactivation, suggesting that tangeretin has the potential to be developed as a new drug for the treatment of bladder cancer.
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Patrauchan, M. A., S. Sarkisova, K. Sauer, and M. J. Franklin. "Calcium influences cellular and extracellular product formation during biofilm-associated growth of a marine Pseudoalteromonas sp." Microbiology 151, no. 9 (September 1, 2005): 2885–97. http://dx.doi.org/10.1099/mic.0.28041-0.
Повний текст джерелаАнотація:
Bacteria undergo a variety of physiological changes following a switch from planktonic growth to surface-associated biofilm growth. Here, it is shown that biofilm development of a marine isolate, Pseudoalteromonas sp. 1398, results in global changes in its cytosolic and extracellular proteomes. Calcium influences these proteome responses, and affects the amount of surface-associated biomass and extracellular matrix material produced by Pseudoalteromonas sp. 1398. Four extracellular proteins, characterized by N-terminal sequencing, showed increased abundances, while one protein, flagellin, showed reduced abundance at higher [Ca2+]. Immunoblotting and transmission-electron-microscopy analysis confirmed that higher [Ca2+] and surface-associated growth results in the repression of flagella production. Two-dimensional gel electrophoresis (2DGE) studies combined with cluster analysis of global proteome responses demonstrated that Ca2+ had a greater regulatory influence on Pseudoalteromonas sp. growing in biofilms than on planktonic cultures. Approximately 22 % of the total cytosolic proteins resolved by 2DGE had differing abundances in response to a switch from planktonic growth to surface-associated growth when the cells were cultivated in 1 mM Ca2+. At higher [Ca2+] this number increased to 38 %. Fifteen cellular proteins that were differentially expressed in response to biofilm growth and/or Ca2+ were analysed by N-terminal sequencing and/or MS/MS. These proteins were identified as factors involved in cellular metabolic functions, putative proteases and transport proteins, although there were several proteins that had not been previously characterized. These results indicate that Ca2+ causes global changes in matrix material, as well as in cellular and extracellular protein profiles of Pseudoalteromonas sp. 1398. These changes are more pronounced when the bacterium grows in biofilms than when it grows in planktonic culture.
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Chen, J., T.-S. Chen, K. I-J Ho, T.-H. Tsai, H.-F. Tsai, M. Hsieh, and T. S. Wang. "A high dynamic range vector quantisation for compressing 2DGE images of different exposures." Imaging Science Journal 59, no. 3 (June 2011): 166–76. http://dx.doi.org/10.1179/136821910x12863757400321.
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Wu, Yajun, Ying Chen, Bin Wang, Haiyan Wang, Fei Yuan, and Guiming Zhao. "2DGE-coomassie brilliant blue staining used to differentiate pasteurized milk from reconstituted milk." Health 01, no. 03 (2009): 146–51. http://dx.doi.org/10.4236/health.2009.13024.
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Wu, Yajun, Ying Chen, Bin Wang, Liqun Bai, Wu ri han, Yiqiang Ge, and Fei Yuan. "Application of SYBRgreen PCR and 2DGE methods to authenticate edible bird's nest food." Food Research International 43, no. 8 (October 2010): 2020–26. http://dx.doi.org/10.1016/j.foodres.2010.05.020.
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Saha, Sutapa, Subrata Banerjee, Debasis Banerjee, Sarmila Chandra, and Abhijit Chakrabarti. "2DGE and DIGE based proteomic study of malignant B-cells in B-cell acute lymphoblastic leukemia." EuPA Open Proteomics 3 (June 2014): 13–26. http://dx.doi.org/10.1016/j.euprot.2014.01.002.
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Rothwell, Stephen W., Ofer Eidelman, Catherine Jozwik, Gregory Mueller, Merrily Poth, Pamela L. Zeitlin, William Guggino, David M. Jacobowitz, Meera Srivastava, and Harvey B. Pollard. "Signalling Pathways Have Different Expression Profiles in Human Platelets Isolated from Men and Women." Blood 108, no. 11 (November 16, 2006): 1519. http://dx.doi.org/10.1182/blood.v108.11.1519.1519.
Повний текст джерелаАнотація:
Abstract Background: Cardiovascular diseases (CVD) are the leading causes of death for men and women in the U.S. Platelets play a central role in the inflammation and coagulation mechanisms responsible for these disorders, and anti-platelet drugs are therefore the current mainstays in prevention and therapy. Understanding the signaling pathways involved in normal and abnormal platelet function using proteomic techniques offers a novel strategic approach to the discovery of potential new therapeutic targets. Hypothesis: The incidence and outcomes of cardiovascular disease are profoundly dependent on gender, and it is possible that differences in platelet signaling mechanisms may contribute to these disparities. We have therefore hypothesized that the platelet signaling proteome is gender-specific. Methods: Platelets were isolated and purified from four normal adult male and four normal adult female donors under an IRB-approved protocol. Conventional 2D-gel electrophoresis (2DGE) and mass spectrometry were used to profile the high abundance platelet proteome. Antibody microarrays, bearing 507 monoclonal antibodies against low abundance proteins involved in signaling pathways and related functions, were used to interrogate the lower abundance platelet. Western blots were used to validate a subset of the data. Results: Discovery studies with 2DGE revealed at least nineteen lower abundance proteins which could be significantly distinguished on the basis of gender (P<0.05). Two of these proteins, a thrombopoeitin-activated G-protein component (#1101) and a megakaryocyte-relevant co-factor for DNA synthesis (#1583), were selectively elevated in male platelets. Concurrent studies on the sensitive antibody microarray platform revealed that more than 420 proteins were significantly expressed in a gender-specific manner (P<0.05). Of these, 62 remained significant by the stringent criterion of a False Discovery Rate (FDR) of <10% (SAM Algorithm, 2000 permutations). By rank-ordering the proteins by expression level, we found that platelets from normal male and female donors were significantly and uniquely enriched in different signaling proteins. These gender-specific signaling proteins included IL-1beta, and specific isoforms of iNOS (inducible nitric oxide synthase), PLC (phospholipase C), and PKC (protein kinase C). Western blot analysis validated a subset of the differentially expressed platelet proteome. Conclusions: These data support the hypothesis that the platelet signaling proteome is gender-specific. We interpret these data to indicate that gender-specific differences in the platelet signaling proteome may contribute to the gender-specific disparity in outcomes for cardiovascular diseases in men and women.
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Wu, Yajun, Bin Wang, Jianxun Han, Zhenmin Zhang, and Ying Chen. "RAPD–2100 bio-analyzer and 2DGE methods applied to qualitatively and quantitatively assess grain purity of commercial malting barley." European Food Research and Technology 234, no. 3 (December 9, 2011): 381–90. http://dx.doi.org/10.1007/s00217-011-1643-1.
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McGill, Melanie A., Diane G. Edmondson, James A. Carroll, Richard G. Cook, Ralph S. Orkiszewski, and Steven J. Norris. "Characterization and Serologic Analysis of the Treponema pallidum Proteome." Infection and Immunity 78, no. 6 (April 12, 2010): 2631–43. http://dx.doi.org/10.1128/iai.00173-10.
Повний текст джерелаАнотація:
ABSTRACT Treponema pallidum subsp. pallidum is the causative agent of syphilis, a sexually transmitted disease characterized by widespread tissue dissemination and chronic infection. In this study, we analyzed the proteome of T. pallidum by the isoelectric focusing (IEF) and nonequilibrating pH gel electrophoresis (NEPHGE) forms of two-dimensional gel electrophoresis (2DGE), coupled with matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) analysis. We determined the identity of 148 T. pallidum protein spots, representing 88 T. pallidum polypeptides; 63 of these polypeptides had not been identified previously at the protein level. To examine which of these proteins are important in the antibody response to syphilis, we performed immunoblot analysis using infected rabbit sera or human sera from patients at different stages of syphilis infection. Twenty-nine previously described antigens (predominantly lipoproteins) were detected, as were a number of previously unidentified antigens. The reactivity patterns obtained with sera from infected rabbits and humans were similar; these patterns included a subset of antigens reactive with all serum samples tested, including CfpA, MglB-2, TmpA, TmpB, flagellins, and the 47-kDa, 17-kDa, and 15-kDa lipoproteins. A unique group of antigens specifically reactive with infected human serum was also identified and included the previously described antigen TpF1 and the hypothetical proteins TP0584, TP0608, and TP0965. This combined proteomic and serologic analysis further delineates the antigens potentially useful as vaccine candidates or diagnostic markers and may provide insight into the host-pathogen interactions that occur during T. pallidum infection.
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Alhajouj, Mohammed S., Ghadah S. Alsharif, and Ahmed A. Mirza. "Impact of Sequential Passaging on Protein Expression of E. coli Using Proteomics Analysis." International Journal of Microbiology 2020 (July 30, 2020): 1–8. http://dx.doi.org/10.1155/2020/2716202.
Повний текст джерелаАнотація:
Urinary tract infection (UTI) is one of the most prevalent bacterial infections in the world affecting the bladder and the kidney. Escherichia coli (E. coli) is the main causative agent of 80–90% of community-acquired UTIs, about 40% of nosocomial UTIs, and 25% of recurrent UTIs. The field of proteomics has emerged as a great tool to analyze expressed proteins to identify possible biomarkers associated with many pathological states and, to the same extent, those associated with bacterial pathogenesis and their ability to cause recurrent infections. Here, in a descriptive cross-sectional pilot study, we employed proteomic techniques to investigate the effects of environmental stress on protein profiles of E. coli simulated by sequential passaging of samples from patients with UTIs to screen for unique proteins that arise under stressful environment and could aid in the early detection of UTIs. Four urine samples were collected from individuals with recurrent UTI and sequentially subcultured; protein samples were extracted from bacterial pellets and analyzed using 2-dimensional gel electrophoresis (2DGE). Protein spots of interest arising from changes in the protein profile were analyzed using liquid chromatography-mass spectrometry (LC-MS/MS) and matched against known databases to identify related proteins. We identified ATPB_ECOBW, ASPA ECOLI, DPS ECOL6, and DCEB ECOLI as proteins associated with higher passaging. We concluded that passaging resulted in identifiable changes in the protein profile of E. coli, namely, proteins that are associated with survival and possible adaptation of bacteria, suggestive of factors contributing to antibiotic resistance and recurrent UTIs. Furthermore, our method could be further used to identify indicator-protein candidates that could be a part of a growing protein database to diagnose and identify causative agents in UTIs.
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Iakovlev, A. A., A. Volkov, O. Bashtovaya, I. Shcherbakova, T. Ghazudin, G. Leonova, and G. Tarasova. "P081 The structure of the proteomic profile and gut microbiota in patients with primary immunodeficiency, common variable immunodeficiency and inflammatory bowel disease." Journal of Crohn's and Colitis 14, Supplement_1 (January 2020): S175—S176. http://dx.doi.org/10.1093/ecco-jcc/jjz203.210.
Повний текст джерелаАнотація:
Abstract Background Infringement of intestinal microbiota in patients with primary immunodeficiency (PID), common variable immunodeficiency (CVID) and ulcerative colitis (UC) continues to be studied. The aim of the research is a comprehensive study of the structure of gut microbiota and mucosal protein profile (MPP) in patients with PID, CVID and UC in different phases of the disease course. Methods The research included 15 patients with PID, 22 CVID and 46 UC (28 with relapse and 18 with persistent remission of the disease), control group—20 healthy volunteers. Estimation of gut microbiota was performed by bacteriological seeding, hydrogen breath test (HBT) with lactulose. Content of short-chain fatty acids (SCFAs) and microbial lipid markers (MLM) in faeces and colon mucosa was determined by gas–liquid chromatographic and gas chromatography–mass spectrometry (GC–MS). MPP was based on isoelectric focusing techniques (SDS–PAGE, 2DGE). Mass spectrograms were obtained using MALDI-TOF-MS/MS (Bruker, USA). Results HBT showed a 4.5-, 8- and 11-fold increase in hydrogen production on a 150th-minute study. SCFA showed a 6-, 9- and 11-fold decrease in propionic and butyric acids, mainly in patients with PID and UC: 0.2 + 0.1, 0.14 + 0.03 and 0.04 + 0.02 mg/g, respectively. Microbiological analysis showed a decrease in titers of E. coli, bifido- and lactobacilli on average 4.6 + 0.8 Lg. The conditionally pathogenic microflora was represented by E. coli, lactose-negative strains (n = 51,105/g) and haemolytic strains (n = 34,104/g, Proteus spp. (n = 48,105/g), Staphylococcus spp. (n = 29,105–6/g), Candida (n = 51,104–6/g) and Clostridium spp. (n = 38,104/g) in stool culture. MLN GS-MS results showed a 5.5-, 3- and 6-fold increase in total bacterial load in patients with PID, CVID and UC, respectively, which was represented by resident anaerobic microflora: Streptococcus mutants, Clostridium difficile, Candida albicans. Results of MPP (detection rate of 75% or more) of the colon mucosa in patients with PID were detected: 1, 2, 4 okkludin, kininogen 1, interleukin-1B, interleukin 8, B2-glycoprotein, heat shock protein 27, in patients with CVID—translational elongation factor, apolipoprotein C-III. In patients with UC—NF-kB, alipoprotein C-III, TNF-α, interleukin-2 and 8 were presented. Conclusion In patients with PID, CVID and UC markers of colon excess growth and significant decrease in SCFA are recorded during the relapse period. MPP in patients with PID, CVID and UC was characterised by proteins characteristic of inflammation, apoptosis, proliferation and proteins reflecting the activity of the autoimmune process. Patients with UC in the remission have recovery trend of gut microbiota, production of SCFA, disappearance of specific components of altered MPP.
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Lee, Sang Woon. "Two-Dimensional Electron Gas at SrTiO3-Based Oxide Heterostructures via Atomic Layer Deposition." Journal of Nanomaterials 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/1671390.
Повний текст джерелаАнотація:
Two-dimensional electron gas (2DEG) at an oxide interface has been attracting considerable attention for physics research and nanoelectronic applications. Early studies reported the formation of 2DEG at semiconductor interfaces (e.g., AlGaAs/GaAs heterostructures) with interesting electrical properties such as high electron mobility. Besides 2DEG formation at semiconductor junctions, 2DEG was realized at the interface of an oxide heterostructure such as the LaAlO3/SrTiO3(LAO/STO) heterojunction. The origin of 2DEG was attributed to the well-known “polar catastrophe” mechanism in oxide heterostructures, which consist of an epitaxial LAO layer on a single crystalline STO substrate among proposed mechanisms. Recently, it was reported that the creation of 2DEG was achieved using the atomic layer deposition (ALD) technique, which opens new functionality of ALD in emerging nanoelectronics. This review is focused on the origin of 2DEG at oxide heterostructures using the ALD process. In particular, it addresses the origin of 2DEG at oxide interfaces based on an alternative mechanism (i.e., oxygen vacancies).
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SMIRNOV, D., V. V. RUDENKOV, B. M. ASHKINADZE, E. COHEN, P. C. M. CHRISTIANEN, J. C. MAAN, and L. N. PFEIFFER. "PHOTOLUMINESCENCE OF A HIGH MOBILITY 2DEG IN THE FRACTIONAL QUANTUM HALL EFFECT REGIME." International Journal of Modern Physics B 21, no. 08n09 (April 10, 2007): 1455–59. http://dx.doi.org/10.1142/s0217979207043002.
Повний текст джерелаАнотація:
The magneto-PL spectra of modulation-doped, ultra-high mobility GaAs/AlGaAs single heterojunctions (HJs) were studied under a perpendicularly applied magnetic field up to 33 T and at temperatures of 0.3 and 1.2 K. The spectra show remarkable intensity redistribution between free (bulk) exciton and 2DEG-hole PL channels occurring at electron filling factors, ν = 2 and 1. At 0.3 K, significant 2DEG-hole PL spectral changes are observed near ν = 2/3 and 1/3. Several heterojunctions with 2DEG density in the range of n2D - (1 - 2.7) · 1011 cm -2 display similar features. These spectral peculiarities are attributed to the modification of the 2DEG energy spectrum caused by the e-e interaction, in particular, the recombination of valence hole with the composite (fractionally-charged) particles of the magnetized 2DEG. In HJs with lower n2D < 1011 cm -2, the observed PL evolution at ν < 1 is mainly determined by an intensity redistribution between the σ+ and σ- circularly-polarized free exciton PL components. In this case, the exciton energy is lower than the energy of the 2DEG-hole system, so that the free excitons do not dissociate near the magnetized 2DEG and thus, the 2DEG-hole PL is barely observed.
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Gall, N. R., E. V. Rut'kov, and A. Ya Tontegode. "Two Dimensional Graphite Films on Metals and Their Intercalation." International Journal of Modern Physics B 11, no. 16 (June 30, 1997): 1865–911. http://dx.doi.org/10.1142/s0217979297000976.
Повний текст джерелаАнотація:
Two-dimensional graphite films (2DGF) on solids are wonderful objects, real nature-made two-dimensional crystals. Formation on active metal surface of a 2DGF with extremely high adsorption, chemical and catalytic passivity leads to a number of staggering effects. The review is devoted to 2DGF on metals and their nature, structure, modes of formation and physico chemical properties. A nature of absorption bond between 2DGF and metal substrate is discussed in details. A special attention is paid to intercalation of 2DGF — a process when foreign atoms and even molecules (fullerenes C 60 molecules) spontaneously penetrate between graphite film and metal substrate. Modes of intercalation are discussed and a mechanism of it, based on thermal movements of carbon atoms of a graphite layer, proposed earlier, is used for explanation of experimental data. A new, practically important effect-superefficient diffusion of alkaline atoms into transition metal bulk, covered by 2DGF, is reported.
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Peng, Da Qing, Xun Dong, Zhong Hui Li, Dong Guo Zhang, Liang Li, Jin Yu Ni, and Wei Ke Luo. "2DEG Transport Properties in AlGaN/GaN Double Heterostructure HEMT with High In Composition InGaN Channel." Advanced Materials Research 805-806 (September 2013): 1027–30. http://dx.doi.org/10.4028/www.scientific.net/amr.805-806.1027.
Повний текст джерелаАнотація:
AlGaN/InGaN/GaN double heterostructure high electron mobility transistor (HEMT) with In composition from 0.08 to 0.26 were grown by MOCVD. 2DEG density and mobility of different channel In composition were investigated. When In composition below 0.19, 2DEG density increased nearly linearly with In composition, and the mobility decreased a bit. While In composition over 0.19, phase separation became more serious, 2DEG density nearly not changed, and the mobility dropped sharply. A high 2DEG mobility of 1163 cm2/V·s with low sheet resistance of 342Ω/ was obtained with In composition 0.19.
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Han, Kun, Kaige Hu, Xiao Li, Ke Huang, Zhen Huang, Shengwei Zeng, Dongchen Qi, et al. "Erasable and recreatable two-dimensional electron gas at the heterointerface of SrTiO3 and a water-dissolvable overlayer." Science Advances 5, no. 8 (August 2019): eaaw7286. http://dx.doi.org/10.1126/sciadv.aaw7286.
Повний текст джерелаАнотація:
While benefiting greatly from electronics, our society also faces a major problem of electronic waste, which has already caused environmental pollution and adverse human health effects. Therefore, recyclability becomes a must-have feature in future electronics. Here, we demonstrate an erasable and recreatable two-dimensional electron gas (2DEG), which can be easily created and patterned by depositing a water-dissolvable overlayer of amorphous Sr3Al2O6 (a-SAO) on SrTiO3 (STO) at room temperature. The 2DEG can be repeatedly erased or recreated by depositing the a-SAO or dissolving in water, respectively. Photoluminescence results show that the 2DEG arises from the a-SAO–induced oxygen vacancy. Furthermore, by gradually depleting the 2DEG, a transition of nonlinear to linear Hall effect is observed, demonstrating an unexpected interfacial band structure. The convenience and repeatability in the creation of the water-dissolvable 2DEG with rich physics could potentially contribute to the exploration of next generation electronics, such as environment-friendly or water-soluble electronics.
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Feng, Qian, Peng Shi, Jie Zhao, Kai Du, Yu Kun Li, Qing Feng, and Yue Hao. "Transport Properties of Two-Dimensional Electron Gas in Cubic AlGaN/GaN Heterostructures." Advanced Materials Research 873 (December 2013): 777–82. http://dx.doi.org/10.4028/www.scientific.net/amr.873.777.
Повний текст джерелаАнотація:
We presented a theoretical study of the dependence of 2DEG mobility on temperature, barrier thickness, Al content, donor concentration to reveal the internal physics of 2DEG mobility in cubic AlGaN/GaNheterostructures. The 2DEG mobility is modeled as a combined effect of the scattering mechanisms including acoustic phonons, ionized impurity, dislocation, alloy disorder and interface roughness scattering.The variation of mobility results mainly from the change of 2DEG density and temperature. It reveals the dominant scattering mechanismsare dislocation and alloy disorder scattering atlow temperature.Acoustic phonons scattering becomes the major limit at 300k. Impurity scattering plays the key role when donor density rises. We find a maximum mobility with a structure of 25% Al content and 4-5nm barrier thickness.
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Javaid Iqbal, Muhammad, Dirk Reuter, Andreas Dirk Wieck, and Caspar van der Wal. "Characterization of low-resistance ohmic contacts to a two-dimensional electron gas in a GaAs/AlGaAs heterostructure." European Physical Journal Applied Physics 89, no. 2 (February 2020): 20101. http://dx.doi.org/10.1051/epjap/2020190202.
Повний текст джерелаАнотація:
The study of electron transport in low-dimensional systems is of importance, not only from a fundamental point of view, but also for future electronic and spintronic devices. In this context heterostructures containing a two-dimensional electron gas (2DEG) are a key technology. In particular GaAs/AlGaAs heterostructures, with a 2DEG at typically 100 nm below the surface, are widely studied. In order to explore electron transport in such systems, low-resistance ohmic contacts are required that connect the 2DEG to macroscopic measurement leads at the surface. Here we report on designing and measuring a dedicated device for unraveling the various resistance contributions in such contacts, which include pristine 2DEG series resistance, the 2DEG resistance under a contact, the contact resistance itself, and the influence of pressing a bonding wire onto a contact. We also report here a recipe for contacts with very low resistance values that remain below 10 Ω for annealing times between 20 and 350 s, hence providing the flexibility to use this method for materials with different 2DEG depths. The type of heating, temperature ramp rate and gas forming used for annealing is found to strongly influence the annealing process and hence the quality of the resulting contacts.
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Cow, Geraline, Charles Gullo, Feng Ge, and Gerrard Teoh. "Protein Mapping and Characterization of Post-Translational Modifications of Ku86 Protein Variants in Multiple Myeloma Cell Lines." Blood 108, no. 11 (November 16, 2006): 3510. http://dx.doi.org/10.1182/blood.v108.11.3510.3510.
Повний текст джерелаАнотація:
Abstract A single biological event, immunoglobulin heavy chain (IgH) isotype class switch recombination (CSR) is thought to mark the onset of multiple myeloma (MM). The DNA repair enzyme, DNA-dependent protein kinase (DNA-PK), which consists of a heterodimeric regulatory subunit (Ku70/Ku86) and its catalytic subunit (DNA-PKcs), is the principal mediator of IgH isotype CSR. Studies in Ku70 and Ku86 knockout mice have suggested that Ku proteins could have a role to play in carcinogenesis. Since we have previously detected truncated variants of Ku86 (Ku86v) in 86% to 100% of freshly isolated patient MM cells, we therefore hypothesize that Ku86v could be a putative oncoprotein. Two variants of Ku86 are predominantly found in MM cells: a 69 kDa variant truncated at the C-terminus (Ku86v-N), which has lost its DNA repair function; and a 56 kDa N-terminus truncated variant (Ku86v-C), which is not translocated into the nucleus and aberrantly expressed on the cell membrane. Our prior studies using Northern blotting, whole cell polyacrylamide gel electrophoresis (PAGE) and electrophoretic mobility shift assays (EMSA) have demonstrated that Ku86vs in MM cells are not the result of alternative RNA splicing; or in vitro degradation, as has been described in human lymphocytes. Moreover, since many proteins in MM cells are known to be heavily glycosylated, and deglycosylation could lead to shorter forms of the protein, we now show using Endo H digestion that Ku86vs are also not the result of N-linked deglycosylation. Rather, Ku86vs are formed by in vivo proteolytic cleavage via a trypsin-like serine protease. Since the proteasome degradation pathway is highly active in MM cells; and protease digestion of DNA-PK holoenzyme is enhanced by proteasome inhibition (i.e. bortezomib treatment), these data support the notion that in vivo activation of putative Ku86v oncoproteins within MM cells could arise via a constitutively active post-translational proteolytic process. To define a functional role for Ku86v, we first demonstrate that Ku86v is physically associated with the most abundant anti-apoptotic protein in MM cells, BCL2. We then used cyanogen bromide immunoprecipitation to purify BCL2-bound Ku86vs followed by 2-dimensional gel electrophoresis (2DGE) to resolve these purified proteins, and demonstrate that only the 56 kDa Ku86v-C (pI 5.0) bound to BCL2. Both full length Ku86 and Ku86v-N were not detected. We then isolated Ku86v-C from the 2D gel and preliminary mass spectrometric analyses suggest that the N-terminus truncation retains the Ku autoantigen related protein 1 (KARP1) motif of Ku86. The significance of this is still under investigation. In conclusion, we have found that Ku86v-C (56 kDa pI 5.0) is formed by post-translational proteolytic cleavage. Since, Ku86v-C is significantly associated with BCL2 oncoprotein, we therefore speculate that Ku86v-C could possibly potentiate BCL2’s anti-apoptotic function. Accordingly, Ku86v-C could be considered as a potential target for therapeutic intervention in MM.
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Defenouillère, Quentin, Agathe Verraes, Clotilde Laussel, Anne Friedrich, Joseph Schacherer, and Sébastien Léon. "The induction of HAD-like phosphatases by multiple signaling pathways confers resistance to the metabolic inhibitor 2-deoxyglucose." Science Signaling 12, no. 597 (September 3, 2019): eaaw8000. http://dx.doi.org/10.1126/scisignal.aaw8000.
Повний текст джерелаАнотація:
Anti-cancer strategies that target the glycolytic metabolism of tumors have been proposed. The glucose analog 2-deoxyglucose (2DG) is imported into cells and, after phosphorylation, becomes 2DG-6-phosphate, a toxic by-product that inhibits glycolysis. Using yeast as a model, we performed an unbiased mass spectrometry–based approach to probe the cellular effects of 2DG on the proteome and study resistance mechanisms to 2DG. We found that two phosphatases that target 2DG-6-phosphate were induced upon exposure to 2DG and participated in 2DG detoxification. Dog1 and Dog2 are HAD (haloacid dehalogenase)–like phosphatases, which are evolutionarily conserved. 2DG induced Dog2 by activating several signaling pathways, such as the stress response pathway mediated by the p38 MAPK ortholog Hog1, the unfolded protein response (UPR) triggered by 2DG-induced ER stress, and the cell wall integrity (CWI) pathway mediated by the MAPK Slt2. Loss of the UPR or CWI pathways led to 2DG hypersensitivity. In contrast, mutants impaired in the glucose-mediated repression of genes were 2DG resistant because glucose availability transcriptionally repressed DOG2 by inhibiting signaling mediated by the AMPK ortholog Snf1. The characterization and genome resequencing of spontaneous 2DG-resistant mutants revealed that DOG2 overexpression was a common strategy underlying 2DG resistance. The human Dog2 homolog HDHD1 displayed phosphatase activity toward 2DG-6-phosphate in vitro and its overexpression conferred 2DG resistance in HeLa cells, suggesting that this 2DG phosphatase could interfere with 2DG-based chemotherapies. These results show that HAD-like phosphatases are evolutionarily conserved regulators of 2DG resistance.
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ASHKINADZE, B. M., E. LINDER, E. COHEN, and L. N. PFEIFFER. "MICROWAVE-MODULATED PHOTOLUMINESCENCE OF A TWO-DIMENSIONAL ELECTRON GAS." International Journal of Modern Physics B 21, no. 08n09 (April 10, 2007): 1541–48. http://dx.doi.org/10.1142/s0217979207043166.
Повний текст джерелаАнотація:
The primary effect of microwave (mw) irradiation on a two dimensional electron gas (2DEG) is heating due to mw absorption by the electrons. At low lattice temperatures, pronounced secondary effects are observed: mw-induced modification of the photoluminescence (PL) spectrum and mw-induced resistance oscillations (MIRO). We present an experimental study of mw-modulated PL (MPL) spectroscopy in modulation-doped GaAs/AlGaAs QW's At low magnetic field strengths (B < 0.5 T ), the analysis of the MPL spectra indicates that they arise of a redistribution of the photoexcited holes within the energy states of the top valence band. This is caused by absorbing low-energy acoustic phonons that are emitted by the mw-heated 2DEG. We propose that these nonequilibrium phonons also affect the 2DEG mobility leading to the MIRO's. For B > 0.5 T and intense mw-irradiation, new optically detected resonances (ODRs) are observed at magnetic fields that depend on the 2DEG density and approximately correspond to integer electron filling factors. We argue that these resonances result from a slight 2DEG density increase under mw irradiation with a concurent, low-energy PL spectral shift due to a small bandgap narrowing.
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Im, Ki-Sik, Mallem Siva Pratap Reddy, Jinseok Choi, Youngmin Hwang, Jea-Seung Roh, Sung Jin An, and Jung-Hee Lee. "Characteristics of GaN-Based Nanowire Gate-All-Around (GAA) Transistors." Journal of Nanoscience and Nanotechnology 20, no. 7 (July 1, 2020): 4282–86. http://dx.doi.org/10.1166/jnn.2020.17784.
Повний текст джерелаАнотація:
We investigate the DC, C–V, and pulse performances in GaN-based nanowire gate-all-around (GAA) transistors with two kinds of geometry: one is AlGaN/GaN heterostructure with two dimensional electron gas (2DEG) channel and the other is only GaN layer without 2DEG channel. From I–V and C–V curves, the fabricated GaN nanowire GAA transistor with AlGaN layer clearly exhibits normally-on operation with negative threshold voltage (Vth) due to the existence of 2DEG channel on the trapezoidal shaped GaN nanowire. On the other hand, the GaN nanowire GAA transistor without AlGaN layer presents a positive Vth (normally-off operation) due to the absent of 2DEG channel on the triangle shaped GaN nanowire. However, both devices show the similar temperaturedependent I–V characteristics due to the combination of bulk channel and surface channel in GaN nanowire GAA channel are mostly contributed, rather than the 2DEG channel. GaN-based nanowire GAA transistors demonstrate to almost negligible current collapse phenomenon due to the perfect GAA gate structure in GaN nanowire. The proposed GaN-based nanowire GAA transistors are very promising candidate for both high power device and nano-electronics application.
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Reddy, Bandugula, and N. Prasad. "2-deoxy-D-glucose combined with ferulic acid enhances radiation response in non-small cell lung carcinoma cells." Open Life Sciences 6, no. 5 (October 1, 2011): 743–55. http://dx.doi.org/10.2478/s11535-011-0038-4.
Повний текст джерелаАнотація:
AbstractThe present study was undertaken to investigate the radiosensitizing effects of 2-deoxy-D-glucose (2DG), a glycolytic inhibitor, and ferulic acid (FA), a phenolic prooxidant, in relatively radioresistant human non-small cell lung carcinoma cells (NCI-H460). NCI-H460 cells were treated with 4 mM 2DG and/or 53.8 µM FA for 24 h and then exposed to 2 Gy irradiation. Compared to cells that were 2 Gy-irradiated alone (50%), FA and 2DG with radiation (FA+2DG+IR) showed additional decrease in cell viability (15%). This has been further validated by decreased (86%) colony formation in 2DG+FA+IR group compared to 2DG (29%), FA (24%) and IR (37%) group alone. Increased apoptotic cells (84%) in 2DG+FA+IR group further confirm the radiosensitizing property of 2DG or FA. In NCI-H460 cells 2DG decreased NADPH levels (10%) and FA increased ROS levels leading to enhanced oxidative damage in the 2DG+FA+IR group. This was reflected as altered mitochondrial membrane potential, increased lipid peroxidative markers (TBARS), DNA damage and decreased intracellular glutathione (GSH) levels in combined treatment groups when compared to radiation or 2DG or FA treatment alone. The present study suggests that FA and 2DG act by increasing oxidative damage in NCI-H460 cells.
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Shimizu, Sunao, Mohammad Saeed Bahramy, Takahiko Iizuka, Shimpei Ono, Kazumoto Miwa, Yoshinori Tokura, and Yoshihiro Iwasa. "Enhanced thermopower in ZnO two-dimensional electron gas." Proceedings of the National Academy of Sciences 113, no. 23 (May 24, 2016): 6438–43. http://dx.doi.org/10.1073/pnas.1525500113.
Повний текст джерелаАнотація:
Control of dimensionality has proven to be an effective way to manipulate the electronic properties of materials, thereby enabling exotic quantum phenomena, such as superconductivity, quantum Hall effects, and valleytronic effects. Another example is thermoelectricity, which has been theoretically proposed to be favorably controllable by reducing the dimensionality. Here, we verify this proposal by performing a systematic study on a gate-tuned 2D electron gas (2DEG) system formed at the surface of ZnO. Combining state-of-the-art electric-double-layer transistor experiments and realistic tight-binding calculations, we show that, for a wide range of carrier densities, the 2DEG channel comprises a single subband, and its effective thickness can be reduced to ∼ 1 nm at sufficiently high gate biases. We also demonstrate that the thermoelectric performance of the 2DEG region is significantly higher than that of bulk ZnO. Our approach opens up a route to exploit the peculiar behavior of 2DEG electronic states and realize thermoelectric devices with advanced functionalities.
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Varnava, Christiana. "2DEG transistors with constrictions." Nature Electronics 3, no. 2 (February 2020): 74. http://dx.doi.org/10.1038/s41928-020-0379-y.
Повний текст джерела
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VYURKOV, VLADIMIR, ANDREY VETROV, and VICTOR RYZHII. "PSEUDO-GAP AND SPIN POLARIZATION IN A TWO-DIMENSIONAL ELECTRON GAS." International Journal of Nanoscience 02, no. 06 (December 2003): 619–24. http://dx.doi.org/10.1142/s0219581x03001747.
Повний текст джерелаАнотація:
Tunneling (one-particle excitation) density of states in the vicinity of Fermi level of a two-dimensional electron gas (2DEG) subjected to an external parallel and zero magnetic field is calculated. It reveals a pseudo-gap recently observed in the experiments. The gap originates in spin polarization of 2DEG. Nonmonotonic dependence of energy on a Landau level filling factor (density) for perpendicular magnetic field was also obtained. It implies the tunneling current peculiarities at filling factors of about 1/2 and 1. The Ising-like model of the exchange interaction in 2DEG was exploited instead of the conventional one. It was crucial to achieve even a qualitative agreement with experimental data.
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PATEL, DIGISH K., A. C. SHARMA, and S. S. Z. ASHRAF. "ELECTRON-IMPURITY SCATTERING IN DOPED SINGLE LAYER GRAPHENE." Modern Physics Letters B 27, no. 05 (February 5, 2013): 1350033. http://dx.doi.org/10.1142/s0217984913500334.
Повний текст джерелаАнотація:
We calculated electron-impurity scattering rate (ℏ/τ) as a function of quasiparticle energy (ε) for doped single layer graphene (SLG), bilayer graphene (BLG) and two-dimensional electron gas (2DEG) at zero temperature. (ℏ/τ) of SLG has been computed analytically as well as numerically. Computed results show that ℏ/τ of SLG; (a) tends to zero at ε = 0 and, (b) it exhibits peak at ≈1.6εf, where εf is Fermi energy. Contrary to this, ℏ/τ of 2DEG and BLG show their maximum values at ε = 0 and decline thereafter on increasing ε to attain a minimum at around ε equal to Fermi energy. We thus find that ℏ/τ versus ε of SLG displays an entirely different behavior than that of BLG and 2DEG, suggesting that electron-impurity scattering process in SLG sharply differs from those in BLG and 2DEG. Further, computed ℏ/τ of SLG exhibits a large variation in its magnitude over the energy range of 0 ≤ ε ≤ 3εf. Estimation of resistivity within Boltzmann transport theory involves an scattering rate averaged over all possible values of ε. It can therefore be inferred that the computation of resistivity with the use of ℏ/τ at ε = εf for comparing the computed results with experimental data can be highly misleading. Scattering rates of SLG, BLG and 2DEG are found increasing on enhancing the impurity concentration.
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Minh, Nguyen Viet. "Electron Mobility in an Unintentionally Doped GaN/AlGaN Surface Quantum Well." Communications in Physics 21, no. 4 (March 12, 2012): 309. http://dx.doi.org/10.15625/0868-3166/21/4/432.
Повний текст джерелаАнотація:
We present a theoretical study the two-dimensional electron gas 2DEG at low temperature in an unintentionally doped GaN/AlGaN surface quantum well, taking adequate account of the roughness-induced scattering mechansms and effect due to sheet polarization charges. Within model of surface quantum wells 2DEG be described by an extended Fang-Howard wave function, we are able to derive an analytic expression for the self-consistent Hartree potential. Thus, we obtained simple expresion describing the enhancement of the 2DEG screening and unscreened\break potentials for different scattering sources. We studied the electron mobility due to different scattering sources and the total electron mobility in an unintentionally doped GaN/AlGaN surface quantum well.
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Yu, Chen-hui, Qing-zhou Luo, Xiang-dong Luo, and Pei-sheng Liu. "Donor-Like Surface Traps on Two-Dimensional Electron Gas and Current Collapse of AlGaN/GaN HEMTs." Scientific World Journal 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/931980.
Повний текст джерелаАнотація:
The effect of donor-like surface traps on two-dimensional electron gas (2DEG) and drain current collapse of AlGaN/GaN high electron mobility transistors (HEMTs) has been investigated in detail. The depletion of 2DEG by the donor-like surface states is shown. The drain current collapse is found to be more sensitive to the addition of positive surface charges. Surface trap states with higher energy levels result in weaker current collapse and faster collapse process. By adopting an optimized backside doping scheme, the electron density of 2DEG has been improved greatly and the current collapse has been greatly eliminated. These results give reference to the improvement in device performance of AlGaN/GaN HEMTs.
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O'Donnell, Allyson F., Rhonda R. McCartney, Dakshayini G. Chandrashekarappa, Bob B. Zhang, Jeremy Thorner та Martin C. Schmidt. "2-Deoxyglucose Impairs Saccharomyces cerevisiae Growth by Stimulating Snf1-Regulated and α-Arrestin-Mediated Trafficking of Hexose Transporters 1 and 3". Molecular and Cellular Biology 35, № 6 (29 грудня 2014): 939–55. http://dx.doi.org/10.1128/mcb.01183-14.
Повний текст джерелаАнотація:
The glucose analog 2-deoxyglucose (2DG) inhibits the growth ofSaccharomyces cerevisiaeand human tumor cells, but its modes of action have not been fully elucidated. Yeast cells lacking Snf1 (AMP-activated protein kinase) are hypersensitive to 2DG. Overexpression of either of two low-affinity, high-capacity glucose transporters, Hxt1 and Hxt3, suppresses the 2DG hypersensitivity ofsnf1Δ cells. The addition of 2DG or the loss of Snf1 reducesHXT1andHXT3expression levels and stimulates transporter endocytosis and degradation in the vacuole. 2DG-stimulated trafficking of Hxt1 and Hxt3 requires Rod1/Art4 and Rog3/Art7, two members of the α-arrestin trafficking adaptor family. Mutations inROD1andROG3that block binding to the ubiquitin ligase Rsp5 eliminate Rod1- and Rog3-mediated trafficking of Hxt1 and Hxt3. Genetic analysis suggests that Snf1 negatively regulates both Rod1 and Rog3, but via different mechanisms. Snf1 activated by 2DG phosphorylates Rod1 but fails to phosphorylate other known targets, such as the transcriptional repressor Mig1. We propose a novel mechanism for 2DG-induced toxicity whereby 2DG stimulates the modification of α-arrestins, which promote glucose transporter internalization and degradation, causing glucose starvation even when cells are in a glucose-rich environment.
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Xu, W. "Dynamical Properties of a Terahertz Driven Two-dimensional Electron Gas." Australian Journal of Physics 53, no. 1 (2000): 87. http://dx.doi.org/10.1071/ph99041.
Повний текст джерелаАнотація:
In this paper, I present a detailed theoretical study on how a nanostructure, such as a semiconductor-based two-dimensional electron gas (2DEG), interacts with a linearly polarised intense laser field. A tractable method in dealing with the time-dependent many-body problem has been developed, from which the electron Green's function, the electron density–density correlation function and the inverse dielectric function matrix for a 2DEG driven by intense laser fields have been obtained. Using these results, the influence of terahertz laser radiation on dynamical properties such as plasmon and optical spectra in a 2DEG is investigated. The results obtained from this study can be used for the case where the intense terahertz radiation is provided by recently developed free-electron laser sources.
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BENDING, S. J., K. VON KLITZING, and K. PLOOG. "WEAK LOCALIZATION AS A PROBE FOR AN INHOMOGENEOUS MAGNETIC FIELD DISTRIBUTION." Modern Physics Letters B 05, no. 05 (February 28, 1991): 323–30. http://dx.doi.org/10.1142/s0217984991000381.
Повний текст джерелаАнотація:
Type II superconducting films have been prepared on top of the two-dimensional electron gas (2DEG) in a GaAs/AlGaAs heterostructure. In an applied magnetic field the inhomogeneous flux distribution at the superconductor is projected down onto the electron gas. At low applied fields the distribution at the 2DEG takes the form of flux tubes which are much narrower than an electron inelastic scattering length. In this regime we observe a qualitatively new weak localization magnetoconductivity proportional to |B| in contrast to the B2 homogeneous result and in semi-quantitative agreement with the theory of Rammer et al.1 We further demonstrate that the 2DEG can be used as a probe of the spatial distribution of an inhomogeneous magnetic field
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Pan, Yu-Zhen, Thomas P. Sutula, and Paul A. Rutecki. "2-Deoxy-d-glucose reduces epileptiform activity by presynaptic mechanisms." Journal of Neurophysiology 121, no. 4 (April 1, 2019): 1092–101. http://dx.doi.org/10.1152/jn.00723.2018.
Повний текст джерелаАнотація:
2-Deoxy-d-glucose (2DG), a glucose analog that inhibits glycolysis, has acute and chronic antiepileptic effects. We evaluated 2DG’s acute effects on synaptic and membrane properties of CA3 pyramidal neurons in vitro. 2DG (10 mM) had no effects on spontaneously occurring postsynaptic currents (PSCs) in 3.5 mM extracellular potassium concentration ([K+]o). In 7.5 mM [K+]o, 2DG significantly reduced the frequency of epileptiform bursting and the charge carried by postsynaptic currents (PSCs) with a greater effect on inward excitatory compared with outward inhibitory charge (71% vs. 40%). In 7.5 mM [K+]o and bicuculline, 2DG reduced significantly the excitatory charge by 67% and decreased the frequency but not amplitude of excitatory PSCs between bursts. In 7.5 mM [K+]o, 2DG reduced pharmacologically isolated inhibitory PSC frequency without a change in amplitude. The frequency but not amplitude of inward miniature PSCs was reduced when 2DG was applied in 7.5 mM [K+]o before bath application of TTX, but there was no effect when 2DG was applied after TTX, indicating a use-dependent uptake of 2DG was required for its actions at a presynaptic locus. 2DG did not alter membrane properties of CA3 neurons except for reducing the slow afterhyperpolarization in 3.5 but not 7.5 mM [K+]o. The reduction in frequency of spontaneous and inward miniature PSCs in elevated [K+]o indicates a presynaptic mechanism of action. 2DG effects required use-dependent uptake and suggest an important role for glycolysis in neuronal metabolism and energetics in states of high neural activity as occur during abnormal network synchronization and seizures. NEW & NOTEWORTHY 2-Deoxy-d-glucose (2DG) is a glycolytic inhibitor and suppresses epileptiform activity acutely and has chronic antiepileptic effects. The mechanisms of the acute effects are not well delineated. In this study, we show 2DG suppressed abnormal network epileptiform activity without effecting normal synaptic network activity or membrane properties. The effects appear to be use dependent and have a presynaptic locus of action. Inhibition of glycolysis is a novel presynaptic mechanism to limit abnormal neuronal network activity and seizures.
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Ahmad, Iman, Ebtihal Mustafa, Noor Mustafa, Lubna Tahtamouni, and Maher Abdalla. "2DG enhances the susceptibility of breast cancer cells to doxorubicin." Open Life Sciences 5, no. 6 (December 1, 2010): 739–48. http://dx.doi.org/10.2478/s11535-010-0060-y.
Повний текст джерелаАнотація:
Abstract2DG causes cytotoxicity in cancer cells by disrupting thiol metabolism while Doxorubicin (DOX) induces cytotoxicity in tumor cells by generating reactive oxygen species (ROS). Here we examined the combined cytotoxic action of 2DG and DOX in rapidly dividing T47D breast cancer cells vs. slowly growing MCF-7 breast cancer cells. T47D cells exposed to the combination of 2DG/DOX significantly decreased cell survival compared to controls, while 2DG/DOX had no effect on MCF-7 cells. 2DG/DOX also disrupted the oxidant status of T47D treated cells, decreased intracellular total glutathione and increased glutathione disulfide (%GSSG) compared to MCF-7 cells. Lipid peroxidation increased in T47D cells treated with 2DG and/or DOX, but not in MCF-7 cells. T47D cells were significantly protected by NAC, indicating that the combined treatment exerts its action by increasing ROS production and disrupting antioxidant stores. When we inhibited glutathione synthesis with BSO, T47D cells became more sensitive to 2DG/DOX-induced cytotoxicity, but NAC significantly reversed this cytotoxic effect. Finally, 2DG/DOX, and BSO significantly increased the %GSSG in T47D cells, an effect which was also reversed by NAC. Our results suggest that exposure of rapidly dividing breast cancer cells to 2DG/DOX enhances cytotoxicity via oxidative stress and via disruptions to thiol metabolism.
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Lu, J., B. Shen, N. J. Tang, D. J. Chen, and Y. D. Zheng. "Anti-Weak Localization of the Two Dimensional Electron Gas in Modulation-Doped AlxGa1-xN/GaN Single Quantum Well." Materials Science Forum 475-479 (January 2005): 1787–90. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.1787.
Повний текст джерелаАнотація:
The weak-localization of the two-dimensional electron gas (2DEG) in a modulation-doped Al0.22Ga0.78N/GaN single quantum well has been investigated through the magnetoresistance measurements. The elastic scattering time τε, dephasing time τφ and spin-orbit(s-o) scattering time τso at various temperatures are obtained. The fitting parameters indicate that the inelastic scatterings to the 2DEG are mainly due to the piezoelectric field and the alloy disorder in the AlxGa1-xN barrier. When the second subband in the triangular quantum well at the heterointerface is occupied by the 2DEG, the anti-weak localization is observed clearly, which is due to the strong spin-orbit interaction. The spin-orbit effect dominates the quantum correction of the conductivity in the upper subband. The intersubband scattering becomes stronger with increasing temperature.
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Herrera-Moro Chao, D., L. León-Mercado, E. Foppen, M. Guzmán-Ruiz, M. C. Basualdo, C. Escobar, and R. M. Buijs. "The Suprachiasmatic Nucleus Modulates the Sensitivity of Arcuate Nucleus to Hypoglycemia in the Male Rat." Endocrinology 157, no. 9 (July 5, 2016): 3439–51. http://dx.doi.org/10.1210/en.2015-1751.
Повний текст джерелаАнотація:
The suprachiasmatic nucleus (SCN) and arcuate nucleus (ARC) have reciprocal connections; catabolic metabolic information activates the ARC and inhibits SCN neuronal activity. Little is known about the influence of the SCN on the ARC. Here, we investigated whether the SCN modulated the sensitivity of the ARC to catabolic metabolic conditions. ARC neuronal activity, as determined by c-Fos immunoreactivity, was increased after a hypoglycemic stimulus by 2-deoxyglucose (2DG). The highest ARC neuronal activity after 2DG was found at the end of the light period (zeitgeber 11, ZT11) with a lower activity in the beginning of the light period (zeitgeber 2, ZT2), suggesting the involvement of the SCN. The higher activation of ARC neurons after 2DG at ZT11 was associated with higher 2DG induced blood glucose levels as compared with ZT2. Unilateral SCN-lesioned animals, gave a mainly ipsilateral activation of ARC neurons at the lesioned side, suggesting an inhibitory role of the SCN on ARC neurons. The 2DG-induced counterregulatory glucose response correlated with increased ARC neuronal activity and was significantly higher in unilateral SCN-lesioned animals. Finally, the ARC as site where 2DG may, at least partly, induce a counterregulatory response was confirmed by local microdialysis of 2DG. 2DG administration in the ARC produced a higher increase in circulating glucose compared with 2DG administration in surrounding areas such as the ventromedial nucleus of the hypothalamus (VMH). We conclude that the SCN uses neuronal pathways to the ARC to gate sensory metabolic information to the brain, regulating ARC glucose sensitivity and counterregulatory responses to hypoglycemic conditions.
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LIU, XIUPING, ZHENGMING XIONG, SHEEN-WOO LEE, JELENA LEVI, SHAHRIAR YAGHOUBI, SANDIP BISWAL, SANJIV SAM GAMBHIR, and ZHEN CHENG. "A NEAR-INFRARED FLUORESCENT DEOXYGLUCOSE DERIVATIVE FOR OPTICAL IMAGING OF EXPERIMENTAL ARTHRITIS." Journal of Innovative Optical Health Sciences 02, no. 02 (April 2009): 179–87. http://dx.doi.org/10.1142/s1793545809000450.
Повний текст джерелаАнотація:
The purpose of this study is to investigate whether a near-infrared fluorescence (NIRF) probe, Cy5.5-D-glucosamine (Cy5.5-2DG), can image arthritis in collagen-induced arthritic (CIA) mice. The presence of arthritis was verified by both visual examination and micro-computed tomography (MicroCT) imaging. CIA mice were imaged by a micro-positron emission tomography (MicroPET) scanner one hour after intravenous injection of 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG). After radioactivity of [18F]FDG decayed away, Cy5.5-2DG was injected into a lateral tail vein of the mice. Arthritic tissue targeting and retention of Cy5.5-2DG in CIA mice were evaluated and quantified by an optical imaging system. Inflammatory tissue in CIA mice was clearly visualized by [18F]FDG-MicroPET scan. NIRF imaging of Cy5.5-2DG in the same mice revealed that the pattern of localization of Cy5.5-2DG in the arthritic tissue was very similar to that of [18F]FDG. Quantification analysis further showed that [18F]FDG uptake in arthritic tissues at one hour post-injection (p.i.) and Cy5.5-2DG uptakes at different time points p.i. were all well correlated (r2over 0.65). In conclusion, Cy5.5-DG can detect arthritic tissues in living mice. The good correlation between the [18F]FDG uptake and Cy5.5-2DG accumulation in the same arthritic tissue warrants further investigation of Cy5.5-2DG as an approach for assessment of anti-inflammatory treatments.