A new criterion is utilized for the interpretation of flow-force relationships in rat liver mitochondria. The criterion is based on the view that the nature of the relationship between the H+/O ratio and the membrane potential can be inferred from the relationship between ohmic-uncoupler-induced extra respiration and the membrane potential. Thus a linear relationship between extra respiration and membrane potential indicates unequivocally the independence of the H+/O ratio from the membrane potential and the leak nature of the resting respiration [Brand, Chien, and Diolez (1994) Biochem. J. 297, 27-29]. On the other hand, a non-linear relationship indicates that the H+/O ratio is dependent on the membrane potential. The experimental assessment of this relationship in the presence of an additional ohmic leak, however, is rendered difficult by both the uncoupler-induced depression of membrane potential and the limited range of dependence of the H+/O ratio on the membrane potential. We have selected conditions, i.e. incubation of mitochondria at low temperatures, where the extent of non-linearity is markedly increased. It appears that the nature of the resting respiration of mitochondria in vitro is markedly dependent on the temperature: at low temperatures the percentage of resting respiration due to membrane leak decreases and that due to intrinsic uncoupling of the proton pumps increases.
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http://dx.doi.org/10.1042/bj3100477 | DOI Listing |
J Am Coll Cardiol
December 2024
Division of Cardiology, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
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Section of Dermatology, Department of Clinical Medicine and Surgery, University of Naples Federico II, Via Pansini 5, 80131 Napoli, Italy.
The COVID-19 pandemic has encouraged the rapid development and licensing of vaccines against SARS-CoV-2. Currently, numerous vaccines are available on a global scale and are based on different mechanisms of action, including mRNA technology, viral vectors, inactive viruses, and subunit particles. Mass vaccination conducted worldwide has highlighted the potential development of side effects, including ones with skin involvement.
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Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 03680 Kyiv, Ukraine.
This work presents the development of an amperometric biosensor for detecting aspartate aminotransferase (AST) activity in biological fluids using a platinum disk electrode as the working transducer. Optimal concentrations of substrates (aspartate, α-ketoglutarate) and the coenzyme (pyridoxal phosphate) were determined to ensure efficient biosensor operation. A semi-permeable poly-m-phenylenediamine membrane was applied to enhance selectivity against electroactive interferents.
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View Article and Find Full Text PDFPharmaceutics
December 2024
Department of Clinical Pharmacy and Biopharmacy, Poznań University of Medical Sciences, Rokietnicka 3, 60-806 Poznań, Poland.
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