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Leishmania, the causative agent of various forms of leishmaniasis, is the significant cause of morbidity and mortality. Regarding energy metabolism, which is an essential factor for the survival, parasites adapt to the environment under low oxygen tension in the host using metabolic systems which are very different from that of the host mammals. We carried out the study of susceptibilities to different inhibitors of mitochondrial electron transport chain and studies on substrate level phosphorylation in wild-type L. donovani. The amastigote forms of L. donovani are independent on oxidative phosphorylation for ATP production. Indeed, its cell growth was not inhibited by excess oligomycin and dicyclohexylcarbodiimide, which are the most specific inhibitors of the mitochondrial Fo/F1-ATP synthase. In contrast, mitochondrial complex I inhibitor rotenone and complex III inhibitor antimycin A inhibited amastigote cell growth, suggesting the role of complex I and complex III in cell survival. Complex II appeared to have no role in cell survival. To further investigate the site of ATP production, we studied the substrate level phosphorylation, which was involved in the synthesis of ATP. Succinate-pyruvate couple showed the highest substrate level phosphorylation in amastigotes whereas NADH-fumarate and NADH-pyruvate couples failed to produce ATP. In contrast, NADPH-fumarate showed the highest rate of ATP formation in promastigotes. Therefore, we can conclude that substrate level phosphorylation is essential for the survival of amastigote forms of Leishmania donovani.
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The role of G protein B subunits in the release of ATP from human erythrocytes

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Previously, we demonstrated that adenosine triphosphate (ATP) is released from human erythrocytes in response to mechanical deformation and that this release requires activation of a signal-transduction pathway involving adenylyl cyclase and the heterotrimeric G protein, Gs. Here we investigate the role of heterotrimeric G proteins of the Gi subtype in the release of ATP from human erythrocytes. In addition, we determined the profile of heterotrimeric G protein ß submits present in these erythrocyte membranes. The activity of Gi was stimulated by incubation of erythrocytes (20% hematocrit) with mastoparin (10 µM). ATP release was measured using the luciferin/luciferase assay. Heterotrimeric G protein ß subunits present in erythrocyte membranes were resolved using gel electrophoresis and subunit specific antibodies. Incubation of human erythrocytes with mastoparan (an activator ofGi/o) resulted in a 4.1 ±0.6-fold increase in ATP present in the medium (P<0.01). Human erythrocyte membranes stain positively for ß subunit types 1, 2, 3 and 4, all of which been reported to activate of some isoforms of adenylyl cyclase. Activation of the heterotrimeric G protein, Gi, results in ATP release from erythrocytes. This effect is may be related to the activity of ß submits associated with this G protein in the human erythrocyte.
Elaboration of an assessment method for plumbing materials contacting drinking water was the main purpose of this study. The investigation was conducted in 8 week cycles in dynamic conditions using a continuous flow reactor. Microbial growth was measured indirectly by a bioluminescence technique (ATP assay). Every week swabs from the surface of tested materials (polypropylene and different types of polyethylene), from the domestic market were collected and the level of bioluminescence was examined. The results obtained from the surface of tested materials were repeatable and clearly approximated those obtained from the surface of a negative control (stainless steel, low susceptibility for microbial growth). The level of bioluminescence (ATP) on the surface of positive control (paraffin, high susceptibility for microbial growth) was many times higher than that observed on other materials. The presented investigation was the main part of a validation process, which in short time will serve to initiate a complete assessment system for organic materials contacting drinking water.
Increase of genetic potential of fast growing chicken broilers to enlarge size of muscles may lead to decrease quality of the meat because of non-adequate amount of nutrient and energy, stored within the eggs, for providing optimal development. Deliver to the chicken embryo additional amount of energy as ATP or ATP attached to the nanoparticles of silver, as a transporting molecule, may promote growth and development of breast muscle. The objective of the investigation was to evaluate the effect of Ag nanoparticles and ATP, administrated in ovo to the embryo, on the morphology of pectoral muscle. The fertilised eggs of Ross 308 (160) were divided into four groups (4 x 40 eggs): without injection (control), with injection of hydrocol-loid of Ag nanoparticles (Nano-Ag), with injection of hydrocolloid of adenosine triphosphate (ATP) and with injection of Nano-Ag conjugated with adenosine triphosphate (Nano-Ag/ATP). At day one of incubation, the eggs were injected into the air sac with 0.3 ml of experimental solutions. Chicken embryo morphology was evaluated according to the Hamburger-Hamilton standard stages of embryo development, furthermore, pectoral muscle was visualized by TEM. Results showed that Nano-Ag, ATP and Nano-Ag/ATP did not affect negatively growth and development. However, ultra morphology of the cross section of embryo pectoral muscles was better structured and muscle was more dense with myofibers when ATP and Ag nanoparticles were applicated. The results indicate that application of Nano-Ag and ATP in ovo can affect morphology of breast muscle, but not affecting embryo growth.
A pilot study on squamous cell lung carcinoma (LC) chemosensitivity in adenosine triphosphate cell viability chemosensitivity assay (ATP-CVA) was performed. Besides the histological investigation, a modified ATP-CVA was used for the analysis of cancer cell chemosensitivity to four drug regimens, including topotecan, a promising agent for non-small-cell lung cancer (NSCLC) chemotherapy. Results of in vitro chemosensitivity testing showed chemoresistance or only weak response in the predominant amount of tumors.
Background: Smooth muscle cells (SMC) constitute the major contractile cell population of blood vessels and inner organs. SMC contraction depends on energy provided by adenosine triphosphate (ATP) catabolism, which can be generated through oxidative phosphorylation in mitochondria or by anaerobic glycolysis. Mitochondrial activity may also modulate smooth muscle tone by biotransformation of vasoactive mediators. Here, we study the role of mitochondrial DNA gene expression for vascular function in vivo. Methods: Since loss of functional mitochondria in SMC may not be compatible with normal development, we generated mice with inducible SMC-specific abrogation of the mitochondrial transcription factor A (Tfam). Deletion of this gene leads to dysfunctional mitochondria and prevents aerobic ATP production in affected cells. Results: Invasive blood pressure monitoring in live animals demonstrated that SMC specific Tfam deletion results in lower blood pressure and a defective blood-pressure response to stress, changes that were not compensated by increased heart rate. The contractility to agonists was reduced in arterial and gastric fundus strips from Tfam-deficient mice. Endothelium-dependent relaxation of arterial strips in response to ACh was also blunted. Conclusion: Our data show that mitochondrial function is needed for normal gastric contraction, vascular tone, and maintenance of normal blood pressure.
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