Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

A deep marine organic carbon reservoir in the non-glacial Cryogenian ocean (Nanhua Basin, South China) revealed by organic carbon isotopes

The late-Cryogenian warm (non-glacial) interval (c.660-c.650 Ma) is potentially of great significance to the co-evolution between life and the surface environment during the emergence of animal life on Earth. In this study, three high-resolution organic carbon isotopic (delta C-13(org) records for the Datangpo/Xiangmeng Formation on the Yangtze Craton are presented. The data derive from drill cores representing different depositional settings at Daotuo (slope setting), Minle (shallow-water basin), and Xiangtan (basin), respectively. The Daotuo and Minle samples exhibit an overall increase of 6-8%o as well as significant isotopic fluctuations following the Tiesi'ao/Sturtian glaciation, while samples from the deeper Xiangtan section show relatively muted fluctuations (+/- 1 parts per thousand) and no overall trend over the same interval. These findings can be plausibly explained by a much longer residence time for marine organic matter, which may have acted as a redox buffer against oxygenation and climate change. The build-up and eventual oxidation of a sub-pycnocline organic carbon reservoir in the redox stratified non-glacial ocean could help to explain the extreme positive and negative carbon isotope perturbations, respectively, in time-equivalent shallow-marine carbonate Platform successions from Mongolia, Australia and Namibia