Página 7 dos resultados de 311 itens digitais encontrados em 0.008 segundos

Activity of alternative oxidase and plant uncoupling mitochondrial protein in potato tubers stored at low temperature or submitted to artificial aging

Pinheiro,Hugo Alves; Borges,Regis; Silva,Marco Aurélio Pedron e; Centeno,Danilo Cruz
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2004 Português
Relevância na Pesquisa
16.997952%
Potato tubers (Solanum tuberosum L. cv. Binje) were stored at 18 and 4ºC in order to verify changes in mitochondrial metabolism, especially in the activities of the alternative oxidase (AOX) and plant uncoupling mitochondria protein (PUMP). Tubers were also sliced and submitted to artificial aging. The oxygen consumption rate (OCR), respiratory control (RC) and ADP/O ratio for mitochondria obtained after storage at 18ºC were not altered, regardless of the time of storage. Considerable increment in OCR, for both respiratory states 3 and 4, was observed after storing the tubers for five and ten days at 4ºC; and it was accomplished by reductions in RC and ADP/O. The AOX activity was evident after five days at 4ºC, and it was enhanced after ten days of storage at that temperature. No significant changes in PUMP activities were observed after one day at 18ºC or at 4ºC, neither after artificial aging. However, increased swelling of potato mitochondria was observed in the presence of valinomycin and linoleic acid when the tubers were kept at 4ºC for five and ten days. Besides the changes in AOX and PUMP activities, slight alterations in ascorbate peroxidase (APX) and catalase (CAT) activities were observed after storing the tubers at 4ºC for 5 days. The activities of these enzymes were higher after storage at 4ºC for 10 days. The results suggest the combined effect of low temperature and time of exposure in promoting AOX activity...

Cost analysis of a project to digitize classic articles in neurosurgery*

Bauer, Kathleen
Fonte: Medical Library Association Publicador: Medical Library Association
Tipo: Artigo de Revista Científica
Publicado em /04/2002 Português
Relevância na Pesquisa
16.997952%
In summer 2000, the Cushing/Whitney Medical Library at Yale University began a demonstration project to digitize classic articles in neurosurgery from the late 1800s and early 1900s. The objective of the first phase of the project was to measure the time and costs involved in digitization, and those results are reported here. In the second phase, metadata will be added to the digitized articles, and the project will be publicized. Thirteen articles were scanned using optical character recognition (OCR) software, and the resulting text files were carefully proofread. Time for photocopying, scanning, and proofreading were recorded. This project achieved an average cost per item (total pages plus images) of $4.12, a figure at the high end of average costs found in other studies. This project experienced high costs for two reasons. First, the articles contained many images, which required extra processing. Second, the older fonts and the poor condition of many of these articles complicated the OCR process. The average article cost $84.46 to digitize. Although costs were high, the selection of historically important articles maximized the benefit gained from the investment in digitization.

Historical Author Affiliations Assist Verification of Automatically Generated MEDLINE® Citations

Sabir, Tehseen F.; Hauser, Susan E.; Thoma, George R.
Fonte: American Medical Informatics Association Publicador: American Medical Informatics Association
Tipo: Artigo de Revista Científica
Publicado em //2006 Português
Relevância na Pesquisa
16.997952%
High OCR error rates encountered in author affiliations increase the manual labor needed to verify MEDLINE citations automatically created from scanned journal articles. This is due to poor OCR recognition of the small text and italics frequently used in printed affiliations. Using author-affiliation relationships found in existing MEDLINE records, the SeekAffiliation (SA) program automatically finds potentially correct and complete affiliations, thereby reducing manual effort and increasing the efficiency of creating the citations.

A modern optical character recognition system in a real world clinical setting: some accuracy and feasibility observations.

Biondich, Paul G.; Overhage, J. Marc; Dexter, Paul R.; Downs, Stephen M.; Lemmon, Larry; McDonald, Clement J.
Fonte: American Medical Informatics Association Publicador: American Medical Informatics Association
Tipo: Artigo de Revista Científica
Publicado em //2002 Português
Relevância na Pesquisa
16.997952%
Advances in optical character recognition (OCR) software and computer hardware have stimulated a reevaluation of the technology and its ability to capture structured clinical data from preexisting paper forms. In our pilot evaluation, we measured the accuracy and feasibility of capturing vitals data from a pediatric encounter form that has been in use for over twenty years. We found that the software had a digit recognition rate of 92.4% (95% confidence interval: 91.6 to 93.2) overall. More importantly, this system was approximately three times as fast as our existing method of data entry. These preliminary results suggest that with further refinements in the approach and additional development, we may be able to incorporate OCR as another method for capturing structured clinical data.

A TRPV Channel Modulates C. elegans Neurosecretion, Larval Starvation Survival, and Adult Lifespan

Lee, Brian H.; Ashrafi, Kaveh
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
16.997952%
For most organisms, food is only intermittently available; therefore, molecular mechanisms that couple sensation of nutrient availability to growth and development are critical for survival. These mechanisms, however, remain poorly defined. In the absence of nutrients, newly hatched first larval (L1) stage Caenorhabditis elegans halt development and survive in this state for several weeks. We isolated mutations in unc-31, encoding a calcium-activated regulator of neural dense-core vesicle release, which conferred enhanced starvation survival. This extended survival was reminiscent of that seen in daf-2 insulin-signaling deficient mutants and was ultimately dependent on daf-16, which encodes a FOXO transcription factor whose activity is inhibited by insulin signaling. While insulin signaling modulates metabolism, adult lifespan, and dauer formation, insulin-independent mechanisms that also regulate these processes did not promote starvation survival, indicating that regulation of starvation survival is a distinct program. Cell-specific rescue experiments identified a small subset of primary sensory neurons where unc-31 reconstitution modulated starvation survival, suggesting that these neurons mediate perception of food availability. We found that OCR-2...

Intraflagellar Transport/Hedgehog-Related Signaling Components Couple Sensory Cilium Morphology and Serotonin Biosynthesis in Caenorhabditis elegans

Moussaif, Mustapha; Sze, Ji Ying
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/04/2009 Português
Relevância na Pesquisa
16.997952%
Intraflagellar transport in cilia has been proposed as a crucial mediator of Hedgehog signal transduction during embryonic pattern formation in both vertebrates and invertebrates. Here, we show that the Hh receptor Patched-related factor DAF-6 and intraflagellar transport modulate serotonin production in Caenorhabditis elegans animals, by remodeling the architecture of dendritic cilia of a pair of ADF serotonergic chemosensory neurons. Wild-type animals under aversive environment drastically reduce DAF-6 expression in glia-like cells surrounding the cilia of chemosensory neurons, resulting in cilium structural remodeling and upregulation of the serotonin-biosynthesis enzyme tryptophan hydroxylase tph-1 in the ADF neurons. These cellular and molecular modifications are reversed when the environment improves. Mutants of daf-6 or intraflagellar transport constitutively upregulate tph-1 expression. Epistasis analyses indicate that DAF-6/intraflagellar transport and the OCR-2/OSM-9 TRPV channel act in concert, regulating two layers of activation of tph-1 in the ADF neurons. The TRPV signaling turns on tph-1 expression under favorable and aversive conditions, whereas inactivation of DAF-6 by stress results in further upregulation of tph-1 independently of OCR-2/OSM-9 activity. Behavioral analyses suggest that serotonin facilitates larval animals resuming development when the environment improves. Our study revealed the cilium structure of serotonergic neurons as a trigger of regulated serotonin production...

Mocr: A novel fusion tag for enhancing solubility that is compatible with structural biology applications

DelProposto, James; Majmudar, Chinmay Y.; Smith, Janet L.; Brown, William Clay
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
16.997952%
A persistent problem in heterologous protein production is insolubility of the target protein when expressed to high level in the host cell. A widely employed strategy for overcoming this problem is the use of fusion tags. The best fusion tags promote solubility, may function as purification handles and either do not interfere with downstream applications or may be removed from the passenger protein preparation. A novel fusion tag is identified that meets these criteria. This fusion tag is a monomeric mutant of the Ocr protein (0.3 gene product) of bacteriophage T7. This fusion tag displays solubilizing activity with a variety of different passenger proteins. We show that it may be used as a purification handle similar to other fusion tags. Its small size and compact structure are compatible with its use in downstream applications of the passenger protein or it may be removed and purified away from the passenger protein. The use of monomeric Ocr (Mocr) as a complement to other fusion tags such as maltose-binding protein will provide greater flexibility in protein production and processing for a wide variety of protein applications.

Heat Avoidance Is Regulated by Transient Receptor Potential (TRP) Channels and a Neuropeptide Signaling Pathway in Caenorhabditis elegans

Glauser, Dominique A.; Chen, Will C.; Agin, Rebecca; MacInnis, Bronwyn L.; Hellman, Andrew B.; Garrity, Paul A.; Tan, Man-Wah; Goodman, Miriam B.
Fonte: Genetics Society of America Publicador: Genetics Society of America
Tipo: Artigo de Revista Científica
Publicado em /05/2011 Português
Relevância na Pesquisa
16.997952%
The ability to avoid noxious extremes of hot and cold is critical for survival and depends on thermal nociception. The TRPV subset of transient receptor potential (TRP) channels is heat activated and proposed to be responsible for heat detection in vertebrates and fruit flies. To gain insight into the genetic and neural basis of thermal nociception, we developed assays that quantify noxious heat avoidance in the nematode Caenorhabditis elegans and used them to investigate the genetic basis of this behavior. First, we screened mutants for 18 TRP channel genes (including all TRPV orthologs) and found only minor defects in heat avoidance in single and selected double and triple mutants, indicating that other genes are involved. Next, we compared two wild isolates of C. elegans that diverge in their threshold for heat avoidance and linked this phenotypic variation to a polymorphism in the neuropeptide receptor gene npr-1. Further analysis revealed that loss of either the NPR-1 receptor or its ligand, FLP-21, increases the threshold for heat avoidance. Cell-specific rescue of npr-1 implicates the interneuron RMG in the circuit regulating heat avoidance. This neuropeptide signaling pathway operates independently of the TRPV genes, osm-9 and ocr-2...

Localizing Blurry and Low-Resolution Text in Natural Images

Sanketi, Pannag; Shen, Huiying; Coughlan, James M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 10/02/2011 Português
Relevância na Pesquisa
16.997952%
There is a growing body of work addressing the problem of localizing printed text regions occurring in natural scenes, all of it focused on images in which the text to be localized is resolved clearly enough to be read by OCR. This paper introduces an alternative approach to text localization based on the fact that it is often useful to localize text that is identifiable as text but too blurry or small to be read, for two reasons. First, an image can be decimated and processed at a coarser resolution than usual, resulting in faster localization before OCR is performed (at full resolution, if needed). Second, in real-time applications such as a cell phone app to find and read text, text may initially be acquired from a lower-resolution video image in which it appears too small to be read; once the text’s presence and location have been established, a higher-resolution image can be taken in order to resolve the text clearly enough to read it.

Interactions of Aging, Overload, and Creatine Supplementation in Rat Plantaris Muscle

Schuenke, Mark D.; Brooks, Naomi E.; Hikida, Robert S.
Fonte: SAGE-Hindawi Access to Research Publicador: SAGE-Hindawi Access to Research
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
16.997952%
Attenuation of age-related sarcopenia by creatine supplementation has been equivocal. In this study, plantaris muscles of young (Y; 5m) and aging (A; 24m) Fisher 344 rats underwent four weeks of either control (C), creatine supplementation (Cr), surgical overload (O), or overload plus creatine (OCr). Creatine alone had no effect on muscle fiber cross-sectional area (CSA) or heat shock protein (HSP70) and increased myonuclear domain (MND) only in young rats. Overload increased CSA and HSP70 content in I and IIA fibers, regardless of age, and MND in IIA fibers of YO rats. CSA and MND increased in all fast fibers of YOCr, and CSA increased in I and IIA fibers of AOCr. OCR did not alter HSP70, regardless of age. MND did not change in aging rats, regardless of treatment. These data indicate creatine alone had no significant effect. Creatine with overload produced no additional hypertrophy relative to overload alone and attenuated overload-induced HSP70 expression.

Basic Test Framework for the Evaluation of Text Line Segmentation and Text Parameter Extraction

Brodić, Darko; Milivojević, Dragan R.; Milivojević, Zoran
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 25/05/2010 Português
Relevância na Pesquisa
16.997952%
Text line segmentation is an essential stage in off-line optical character recognition (OCR) systems. It is a key because inaccurately segmented text lines will lead to OCR failure. Text line segmentation of handwritten documents is a complex and diverse problem, complicated by the nature of handwriting. Hence, text line segmentation is a leading challenge in handwritten document image processing. Due to inconsistencies in measurement and evaluation of text segmentation algorithm quality, some basic set of measurement methods is required. Currently, there is no commonly accepted one and all algorithm evaluation is custom oriented. In this paper, a basic test framework for the evaluation of text feature extraction algorithms is proposed. This test framework consists of a few experiments primarily linked to text line segmentation, skew rate and reference text line evaluation. Although they are mutually independent, the results obtained are strongly cross linked. In the end, its suitability for different types of letters and languages as well as its adaptability are its main advantages. Thus, the paper presents an efficient evaluation method for text analysis algorithms.

Endothelial Cell and Platelet Bioenergetics: Effect of Glucose and Nutrient Composition

Fink, Brian D.; Herlein, Judy A.; O’Malley, Yunxia; Sivitz, William I.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 22/06/2012 Português
Relevância na Pesquisa
16.997952%
It has been suggested that cells that are independent of insulin for glucose uptake, when exposed to high glucose or other nutrient concentrations, manifest enhanced mitochondrial substrate oxidation with consequent enhanced potential and generation of reactive oxygen species (ROS); a paradigm that could predispose to vascular complications of diabetes. Here we exposed bovine aortic endothelial (BAE) cells and human platelets to variable glucose and fatty acid concentrations. We then examined oxygen consumption and acidification rates using recently available technology in the form of an extracellular oxygen and proton flux analyzer. Acute or overnight exposure of confluent BAE cells to glucose concentrations from 5.5 to 25 mM did not enhance or change the rate of oxygen consumption (OCR) under basal conditions, during ATP synthesis, or under uncoupled conditions. Glucose also did not alter OCR in sub-confluent cells, in cells exposed to low serum, or in cells treated with added pyruvate. Likewise, overnight exposure to fatty acids of varying saturation had no such effects. Overnight exposure of BAE cells to low glucose concentration decreased maximal uncoupled respiration, but not basal or ATP related oxygen consumption. Labeled glucose oxidation to CO2 increased...

Fatty Acid Oxidation Is Essential for Egg Production by the Parasitic Flatworm Schistosoma mansoni

Huang, Stanley Ching-Cheng; Freitas, Tori C.; Amiel, Eyal; Everts, Bart; Pearce, Erika L.; Lok, James B.; Pearce, Edward J.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
16.997952%
Schistosomes, parasitic flatworms that cause the neglected tropical disease schistosomiasis, have been considered to have an entirely carbohydrate based metabolism, with glycolysis playing a dominant role in the adult parasites. However, we have discovered a close link between mitochondrial oxygen consumption by female schistosomes and their ability to produce eggs. We show that oxygen consumption rates (OCR) and egg production are significantly diminished by pharmacologic inhibition of carnitine palmitoyl transferase 1 (CPT1), which catalyzes a rate limiting step in fatty acid β-oxidation (FAO) and by genetic loss of function of acyl CoA synthetase, which complexes with CPT1 and activates long chain FA for use in FAO, and of acyl CoA dehydrogenase, which catalyzes the first step in FAO within mitochondria. Declines in OCR and egg production correlate with changes in a network of lipid droplets within cells in a specialized reproductive organ, the vitellarium. Our data point to the importance of regulated lipid stores and FAO for the compartmentalized process of egg production in schistosomes.

Lateral Entorhinal Cortex is Critical for Novel Object-Context Recognition

Wilson, David IG; Langston, Rosamund F; Schlesiger, Magdalene I; Wagner, Monica; Watanabe, Sakurako; Ainge, James A
Fonte: Wiley Subscription Services, Inc., A Wiley Company Publicador: Wiley Subscription Services, Inc., A Wiley Company
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
16.997952%
Episodic memory incorporates information about specific events or occasions including spatial locations and the contextual features of the environment in which the event took place. It has been modeled in rats using spontaneous exploration of novel configurations of objects, their locations, and the contexts in which they are presented. While we have a detailed understanding of how spatial location is processed in the brain relatively little is known about where the nonspatial contextual components of episodic memory are processed. Initial experiments measured c-fos expression during an object-context recognition (OCR) task to examine which networks within the brain process contextual features of an event. Increased c-fos expression was found in the lateral entorhinal cortex (LEC; a major hippocampal afferent) during OCR relative to control conditions. In a subsequent experiment it was demonstrated that rats with lesions of LEC were unable to recognize object-context associations yet showed normal object recognition and normal context recognition. These data suggest that contextual features of the environment are integrated with object identity in LEC and demonstrate that recognition of such object-context associations requires the LEC. This is consistent with the suggestion that contextual features of an event are processed in LEC and that this information is combined with spatial information from medial entorhinal cortex to form episodic memory in the hippocampus. © 2013 Wiley Periodicals...

Hyperoxia Decreases Glycolytic Capacity, Glycolytic Reserve and Oxidative Phosphorylation in MLE-12 Cells and Inhibits Complex I and II Function, but Not Complex IV in Isolated Mouse Lung Mitochondria

Das, Kumuda C.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 02/09/2013 Português
Relevância na Pesquisa
16.997952%
High levels of oxygen (hyperoxia) are frequently used in critical care units and in conditions of respiratory insufficiencies in adults, as well as in infants. However, hyperoxia has been implicated in a number of pulmonary disorders including bronchopulmonary dysplasia (BPD) and adult respiratory distress syndrome (ARDS). Hyperoxia increases the generation of reactive oxygen species (ROS) in the mitochondria that could impair the function of the mitochondrial electron transport chain. We analyzed lung mitochondrial function in hyperoxia using the XF24 analyzer (extracellular flux) and optimized the assay for lung epithelial cells and mitochondria isolated from lungs of mice. Our data show that hyperoxia decreases basal oxygen consumption rate (OCR), spare respiratory capacity, maximal respiration and ATP turnover in MLE-12 cells. There was significant decrease in glycolytic capacity and glycolytic reserve in MLE-12 cells exposed to hyperoxia. Using mitochondria isolated from lungs of mice exposed to hyperoxia or normoxia we have shown that hyperoxia decreased the basal, state 3 and state3 μ (respiration in an uncoupled state) respirations. Further, using substrate or inhibitor of a specific complex we show that the OCR via complex I and II...

Minor Role of Mitochondrial Respiration for Fatty-Acid Induced Insulin Secretion

Schulz, Nadja; Kluth, Oliver; Jastroch, Martin; Schürmann, Annette
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 16/09/2013 Português
Relevância na Pesquisa
16.997952%
An appropriate insulin secretion by pancreatic beta-cells is necessary to maintain glucose homeostasis. A rise in plasma glucose leads to increased metabolism and an elevated cytoplasmic ATP/ADP ratio that finally triggers insulin granule exocytosis. In addition to this triggering pathway, one or more amplifying pathways—activated by amino acids or fatty acid—enhance secretion by promoting insulin granule recruitment to, and priming at, the plasma membrane. The aim of this study was to clarify the impact of the mitochondrial respiratory activity on fatty acid-induced insulin secretion that was assessed by an extracellular flux analyzer. Treatment of isolated mouse islets with glucose (20 mM) increased insulin secretion 18-fold and correlated with ATP-synthesizing respiration. Furthermore, oxygen consumption rate (OCR) significantly increased by 62% in response to glucose, whereas the addition of palmitate resulted only in a minor increase of OCR at both 2.8 mM (11%) and 20 mM glucose (21%). The addition of palmitate showed a pronounced increase of coupling efficiency (CE) at 2.8 mM glucose but no further insulin secretion. However, treatment with palmitate at 20 mM glucose increased insulin secretion about 32-fold accompanied by a small increase in CE. Thus...

Magnesium Sulfate Protects Against the Bioenergetic Consequences of Chronic Glutamate Receptor Stimulation

Clerc, Pascaline; Young, Christina A.; Bordt, Evan A.; Grigore, Alina M.; Fiskum, Gary; Polster, Brian M.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 13/11/2013 Português
Relevância na Pesquisa
16.997952%
Extracellular glutamate is elevated following brain ischemia or trauma and contributes to neuronal injury. We tested the hypothesis that magnesium sulfate (MgSO4, 3 mM) protects against metabolic failure caused by excitotoxic glutamate exposure. Rat cortical neuron preparations treated in medium already containing a physiological concentration of Mg2+ (1 mM) could be segregated based on their response to glutamate (100 µM). Type I preparations responded with a decrease or small transient increase in oxygen consumption rate (OCR). Type II neurons responded with >50% stimulation in OCR, indicating a robust response to increased energy demand without immediate toxicity. Pre-treatment with MgSO4 improved the initial bioenergetic response to glutamate and ameliorated subsequent loss of spare respiratory capacity, measured following addition of the uncoupler FCCP, in Type I but not Type II neurons. Spare respiratory capacity in Type I neurons was also improved by incubation with MgSO4 or NMDA receptor antagonist MK801 in the absence of glutamate treatment. This finding indicates that the major difference between Type I and Type II preparations is the amount of endogenous glutamate receptor activity. Incubation of Type II neurons with 5 µM glutamate prior to excitotoxic (100 µM) glutamate exposure recapitulated a Type I phenotype. MgSO4 protected against an excitotoxic glutamate-induced drop in neuronal ATP both with and without prior 5 µM glutamate exposure. Results indicate that MgSO4 protects against chronic moderate glutamate receptor stimulation and preserves cellular ATP following treatment with excitotoxic glutamate.

cGMP-Selective Phosphodiesterase Inhibitors Stimulate Mitochondrial Biogenesis and Promote Recovery from Acute Kidney Injury

Whitaker, Ryan M.; Wills, Lauren P.; Stallons, L. Jay; Schnellmann, Rick G.
Fonte: The American Society for Pharmacology and Experimental Therapeutics Publicador: The American Society for Pharmacology and Experimental Therapeutics
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
16.997952%
Recent studies demonstrate that mitochondrial dysfunction is a mediator of acute kidney injury (AKI). Consequently, restoration of mitochondrial function after AKI may be key to the recovery of renal function. Mitochondrial function can be restored through the generation of new, functional mitochondria in a process called mitochondrial biogenesis (MB). Despite its potential therapeutic significance, very few pharmacological agents have been identified to induce MB. To examine the efficacy of phosphodiesterase (PDE) inhibitors (PDE3: cAMP and cGMP activity; and PDE4: cAMP activity) in stimulating MB, primary cultures of renal proximal tubular cells (RPTCs) were treated with a panel of inhibitors for 24 hours. PDE3, but not PDE4, inhibitors increased the FCCP-uncoupled oxygen consumption rate (OCR), a marker of MB. Exposure of RPTCs to the PDE3 inhibitors, cilostamide and trequinsin, for 24 hours increased peroxisome proliferator–activated receptor γ coactivator-1α, and multiple mitochondrial electron transport chain genes. Cilostamide and trequinsin also increased mRNA expression of mitochondrial genes and mitochondrial DNA copy number in mice renal cortex. Consistent with these experiments, 8-Br-cGMP increased FCCP-uncoupled OCR and mitochondrial gene expression...

Metabolic profile analysis of a single developing zebrafish embryo via monitoring of oxygen consumption rates within a microfluidic device

Huang, Shih-Hao; Huang, Kuo-Sheng; Yu, Chu-Hung; Gong, Hong-Yi
Fonte: AIP Publishing LLC Publicador: AIP Publishing LLC
Tipo: Artigo de Revista Científica
Publicado em 22/11/2013 Português
Relevância na Pesquisa
16.997952%
A combination of a microfluidic device with a light modulation system was developed to detect the oxygen consumption rate (OCR) of a single developing zebrafish embryo via phase-based phosphorescence lifetime detection. The microfluidic device combines two components: an array of glass microwells containing Pt(II) octaethylporphyrin as an oxygen-sensitive luminescent layer and a microfluidic module with pneumatically actuated glass lids above the microwells to controllably seal the microwells of interest. The total basal respiration (OCR, in pmol O2/min/embryo) of a single developing zebrafish embryo inside a sealed microwell has been successfully measured from the blastula stage (3 h post-fertilization, 3 hpf) through the hatching stage (48 hpf). The total basal respiration increased in a linear and reproducible fashion with embryonic age. Sequentially adding pharmacological inhibitors of bioenergetic pathways allows us to perform respiratory measurements of a single zebrafish embryo at key developmental stages and thus monitor changes in mitochondrial function in vivo that are coordinated with embryonic development. We have successfully measured the metabolic profiles of a single developing zebrafish embryo from 3 hpf to 48 hpf inside a microfluidic device. The total basal respiration is partitioned into the non-mitochondrial respiration...

Modulation of mitochondrial bioenergetics in a skeletal muscle cell line model of mitochondrial toxicity☆

Dott, William; Mistry, Pratibha; Wright, Jayne; Cain, Kelvin; Herbert, Karl E
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em 10/01/2014 Português
Relevância na Pesquisa
16.997952%
Mitochondrial toxicity is increasingly being implicated as a contributing factor to many xenobiotic-induced organ toxicities, including skeletal muscle toxicity. This has necessitated the need for predictive in vitro models that are able to sensitively detect mitochondrial toxicity of chemical entities early in the research and development process. One such cell model involves substituting galactose for glucose in the culture media. Since cells cultured in galactose are unable to generate sufficient ATP from glycolysis they are forced to rely on mitochondrial oxidative phosphorylation for ATP generation and consequently are more sensitive to mitochondrial perturbation than cells grown in glucose. The aim of this study was to characterise cellular growth, bioenergetics and mitochondrial toxicity of the L6 rat skeletal muscle cell line cultured in either high glucose or galactose media. L6 myoblasts proliferated more slowly when cultured in galactose media, although they maintained similar levels of ATP. Galactose cultured L6 cells were significantly more sensitive to classical mitochondrial toxicants than glucose-cultured cells, confirming the cells had adapted to galactose media. Analysis of bioenergetic function with the XF Seahorse extracellular flux analyser demonstrated that oxygen consumption rate (OCR) was significantly increased whereas extracellular acidification rate (ECAR)...