排序方式： 共有14条查询结果，搜索用时 15 毫秒
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Anne S. Jürgens Mateusz Kolanczyk Dietrich C. C. Moebest Tomasz Zemojtel Urs Lichtenauer Marlena Duchniewicz Melanie P. Gantert Jochen Hecht Uwe Hattenhorst Stefan Burdach Annette Dorn Mark P. Kamps Felix Beuschlein Daniel Räpple Jürgen S. Scheele 《In vitro cellular & developmental biology. Animal》2009,45(5-6):252-263
Experimentation with PBX1 knockout mice has shown that PBX1 is necessary for early embryogenesis. Despite broad insight into PBX1 function, little is known about the underlying target gene regulation. Utilizing the Cre–loxP system, we targeted a functionally important part of the homeodomain of PBX1 through homozygous deletion of exon-6 and flanking intronic regions leading to exon 7 skipping in embryonic stem (ES) cells. We induced in vitro differentiation of wild-type and PBX1 mutant ES cells by aggregation and retinoic acid (RA) treatment and compared their profiles of gene expression at the ninth day post-reattachment to adhesive media. Our results indicate that PBX1 interactions with HOX proteins and DNA are dispensable for RA-induced ability of ES to express neural genes and point to a possible involvement of PBX1 in the regulation of imprinted genes. 相似文献
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The histological effect on and stress response of post juvenile Clarias gariepinus exposed to Qua Iboe crude oil and rig wash were investigated. Fish weighing 60–90 g and measuring 16–18 cm were exposed for 7–28 days to 8.00 ml?1 Qua Iboe crude oil and 0.0018 ml–1 rig wash, both being 0.1 of the 96 hr LC50. Blood samples of C. gariepinus were collected every seven days and evaluated for stress by measuring cortisol concentration. The gills and liver were studied and scored for Gill Alteration Index (GAI) and Hepatic Alteration Index (HAI), respectively. There was an increase in cortisol level up to the 7th and 14th day among the group exposed to Qua Iboe crude oil, with a decrease on the 21st and 28th day. The rig wash group increased in cortisol level up to the 7th day and decreased slightly on the 14th day, after which the trend became irregular. The toxic effects of the Qua Iboe crude oil and rig wash were time dependent, as shown by the histopathological alteration index (HAI) of gill and liver. After 28 days of exposure, the gills had irreparable damage due to high frequency of cellular necrosis and degeneration, whereas the liver had from moderate to severe damage due to the high frequency of cellular degeneration and inflammation. Qua Iboe crude oil and rig wash are both toxic to C. gariepinus, therefore their indiscriminate discharge to the environment must be discouraged. 相似文献
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Alexander Kypta Hermann Blessberger Michael Lichtenauer Thomas Lambert Juergen Kammler Clemens Steinwender 《Indian pacing and electrophysiology journal》2015,15(6):291-292
A 65-year-old man was scheduled for pacemaker implantation for symptomatic sick-sinus-syndrome (SSS). He suffered from multiple drug-allergies and allergies to several metals like quicksilver and titanium. Gold-coated pacemaker generators and polyurethane leads are effective in avoiding allergic reactions to pacing system components. Therefore, we decided to implant a custom-made gold-coated DDDR-pacemaker generator and polyurethane leads. 相似文献
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Jos Manuel Ugalde Isabel Aller Lika Kudrjasova Romy R Schmidt Michelle Schlßer Maria Homagk Philippe Fuchs Sophie Lichtenauer Markus Schwarzlnder Stefanie J Müller-Schüssele Andreas J Meyer 《The Plant cell》2022,34(10):4007
Oxidative protein folding in the endoplasmic reticulum (ER) depends on the coordinated action of protein disulfide isomerases and ER oxidoreductins (EROs). Strict dependence of ERO activity on molecular oxygen as the final electron acceptor implies that oxidative protein folding and other ER processes are severely compromised under hypoxia. Here, we isolated viable Arabidopsis thaliana ero1 ero2 double mutants that are highly sensitive to reductive stress and hypoxia. To elucidate the specific redox dynamics in the ER in vivo, we expressed the glutathione redox potential (EGSH) sensor Grx1-roGFP2iL-HDEL with a midpoint potential of −240 mV in the ER of Arabidopsis plants. We found EGSH values of −241 mV in wild-type plants, which is less oxidizing than previously estimated. In the ero1 ero2 mutants, luminal EGSH was reduced further to −253 mV. Recovery to reductive ER stress induced by dithiothreitol was delayed in ero1 ero2. The characteristic signature of EGSH dynamics in the ER lumen triggered by hypoxia was affected in ero1 ero2 reflecting a disrupted balance of reductive and oxidizing inputs, including nascent polypeptides and glutathione entry. The ER redox dynamics can now be dissected in vivo, revealing a central role of EROs as major redox integrators to promote luminal redox homeostasis.Dynamic monitoring of the ER luminal glutathione redox potential highlights the role of ER oxidoreductins in defining redox conditions and the interplay between different redox inputs during hypoxia and reductive stress.IN A NUTSHELL Background: Most secreted proteins contain disulfide bridges that are essential for their structure and function. Those disulfides are introduced into the nascent polypeptide through the oxidation of cysteines in the endoplasmic reticulum (ER) lumen. Oxidative protein folding requires molecular oxygen (O2) as ultimate electron acceptor. The final electron transfer is catalyzed by thiol oxidases called ER oxidoreductins (EROs). Question: What is the role of EROs in maintaining ER redox homeostasis at steady state and when oxygen supply is limiting? Finding: Arabidopsis thaliana contains two ERO genes. An ero1 ero2 double mutant generated by combining a null allele for ERO1 with a knockdown allele for ERO2 showed enhanced sensitivity towards thiol-based reductive challenge and hypoxia. By monitoring the glutathione redox potential EGSH in the ER lumen using the redox biosensor variant roGFP2iL we measured −241 mV in the wild-type, which is a less oxidizing value than previously thought. A good match between the midpoint potential of the biosensor variant and the physiological EGSH in the ER lumen enabled dynamic measurements indicating ERO activity in vivo. Diminished ERO activity in ero1 ero2 caused a reductive shift to −253 mV and delayed recovery after reductive challenge. The dynamics of luminal EGSH under hypoxia in ero1 ero2 differed from the response obtained in wild-type plants, indicating that ERO activity plays a key role in luminal redox homeostasis. Next steps: Monitoring luminal EGSH represents a platform for evaluating ER redox dynamics and allows assessing other candidates for their potential contribution to oxidative protein folding and maintaining luminal redox homeostasis. Future research may focus on the integration of ER redox homeostasis and phytohormone signaling especially under stress situations or during developmental phases associated with hypoxic conditions. 相似文献
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It has been reported in some cases that an increase in pCO2 stimulates growth in diluted cell suspension cultures. Experiments have been designed to study the pattern of dark CO2 fixation in sycamore cells grown in liquid suspension and to correlate this pattern with the culture growth phases. Comparisons were made between enzymatic activities, CO2 incorporation, malic acid content during lag, logarithmic and stationary phases of growth. Malic enzyme (NADP-dependent) was at its maximum activity during early logarithmic growth phase, when biosynthetic capacities were at the highest. Phosphoenolpyruvate-carboxylase activity was strongly correlated with the ability of cells to fix CO2. Malic acid content decreased soon after transfer of the cells to a new medium and increased at the onset of stationary phase. Under optimal conditions, the CO2 incorporation pattern did not change during growth, with an almost identical incorporation in the basic (amino acids) and acidic (organic acids) fractions. These observations have been discussed in relation to a possible effect of increased pCO2 in the cell environment. 相似文献
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Michael Lichtenauer Michael Mildner Gregor Werba Lucian Beer Konrad Hoetzenecker Andrea Baumgartner Matthias Hasun Stefanie Nickl Andreas Mitterbauer Matthias Zimmermann Mariann Gy?ngy?si Bruno Karl Podesser Walter Klepetko Hendrik Jan Ankersmit 《PloS one》2012,7(12)
Rationale
Acute myocardial infarction (AMI) followed by ventricular remodeling is the major cause of congestive heart failure and death in western world countries.Objective
Of relevance are reports showing that infusion of apoptotic leucocytes or anti-lymphocyte serum after AMI reduces myocardial necrosis and preserves cardiac function. In order to corroborate this therapeutic mechanism, the utilization of an immunosuppressive agent with a comparable mechanism, such as anti-thymocyte globulin (ATG) was evaluated in this study.Methods and Results
AMI was induced in rats by ligation of the left anterior descending artery. Initially after the onset of ischemia, rabbit ATG (10 mg/rat) was injected intravenously. In vitro and in vivo experiments showed that ATG induced a pronounced release of pro-angiogenic and chemotactic factors. Moreover, paracrine factors released from ATG co-incubated cell cultures conferred a down-regulation of p53 in cardiac myocytes. Rats that were injected with ATG evidenced higher numbers of CD68+ macrophages in the ischemic myocardium. Animals injected with ATG evidenced less myocardial necrosis, showed a significant reduction of infarct dimension and an improvement of post-AMI remodeling after six weeks (infarct dimension 24.9% vs. 11.4%, p<0.01). Moreover, a higher vessel density in the peri-infarct region indicated a better collateralization in rats that were injected with ATG.Conclusions
These data indicate that ATG, a therapeutic agent successfully applied in clinical transplant immunology, triggered cardioprotective effects after AMI that salvaged ischemic myocardium by down-regulation of p53. This might have raised the resistance against apoptotic cell death during ischemia. The combination of these mechanisms seems to be causative for improved cardiac function and less ventricular remodeling after experimental AMI. 相似文献10.
Cristina Ruberti Elias Feitosa-Araujo Zhaolong Xu Stephan Wagner Matteo Grenzi Essam Darwish Sophie Lichtenauer Philippe Fuchs Ambra Selene Parmagnani Daria Balcerowicz Sbastjen Schoenaers Carolina de la Torre Khansa Mekkaoui Adriano Nunes-Nesi Markus Wirtz Kris Vissenberg Olivier Van Aken Bettina Hause Alex Costa Markus Schwarzlnder 《The Plant cell》2022,34(11):4428
Ca2+ signaling is central to plant development and acclimation. While Ca2+-responsive proteins have been investigated intensely in plants, only a few Ca2+-permeable channels have been identified, and our understanding of how intracellular Ca2+ fluxes is facilitated remains limited. Arabidopsis thaliana homologs of the mammalian channel-forming mitochondrial calcium uniporter (MCU) protein showed Ca2+ transport activity in vitro. Yet, the evolutionary complexity of MCU proteins, as well as reports about alternative systems and unperturbed mitochondrial Ca2+ uptake in knockout lines of MCU genes, leave critical questions about the in vivo functions of the MCU protein family in plants unanswered. Here, we demonstrate that MCU proteins mediate mitochondrial Ca2+ transport in planta and that this mechanism is the major route for fast Ca2+ uptake. Guided by the subcellular localization, expression, and conservation of MCU proteins, we generated an mcu triple knockout line. Using Ca2+ imaging in living root tips and the stimulation of Ca2+ transients of different amplitudes, we demonstrated that mitochondrial Ca2+ uptake became limiting in the triple mutant. The drastic cell physiological phenotype of impaired subcellular Ca2+ transport coincided with deregulated jasmonic acid-related signaling and thigmomorphogenesis. Our findings establish MCUs as a major mitochondrial Ca2+ entry route in planta and link mitochondrial Ca2+ transport with phytohormone signaling.Monitoring of subcellular Ca2+ dynamics in living Arabidopsis roots reveals that MCU proteins provide the dominant mitochondrial Ca2+ uptake mechanism in vivo. 相似文献