Cyclic electron flow around photosystem I (CEF) is critical for balancing the photosynthetic energy budget of the chloroplast, by generating ATP without net production of NADPH. We demonstrate that the chloroplast NADPH dehydrogenase complex (NDH), a homolog to respiratory Complex I, pumps approximately two protons from the chloroplast stroma to the lumen per electron transferred from ferredoxi...

1. Mitochondria from the parasitic nematode worm Nippostrongylus brasiliensis produce H2O2 in the energized state; higher rates of H2O2 production were observed in the presence of the uncoupler carbonyl cyanide m-chlorophenylhydrazone. 2. Antimycin A inhibits respiration and H2O2 production by 70 and 65% respectively; the residual activities can be attributed to alternative electron-transport p...

Executive Summary We propose a program of study of the interaction of electrons and photons in fields approaching the critical QED field strength of an electron rest energy per Compton wavelength. This can be achieved in collisions between the picosecond pulses of a teraWatt laser and a 50-GeV electron beam. The phenomena accessible to study include nonlinear Compton scattering , trident produc...

One of the basic mechanisms of photo-bio-modulation is the acceleration of electron transfer by electromagnetic radiation in the visible and near infra-red region of the spectrum [1,2]. In the presence of an electron acceptor such as molecular oxygen (O2), electron transfer reduces O2 to the super-oxide anion O2 , which subsequently dismutates into hydrogen peroxide (H2O2) [3]. Both O2 and H2O2...

the objective of this study was to determine the effect of irradiation of pomegranate seed (ps) on chemical composition, digestibility and kinetic of gas production. pomegranate seeds were exposed to gamma ray (gr) and electron beam (eb) at doses of 5, 10, 15 and 20 kgy. three ruminally fistulated rams were used for obtaining ruminal fluid for in vitro digestibility and gas production measuremen...

[1] We investigate the extreme ionospheric effect during the intense solar flare (X17.0/3B) that occurred on 7 September 2005. A strong E region electron density enhancement is observed by the incoherent scatter radars at Millstone Hill, Sondrestrom, and Tromsø, as well as by the radio occultation experiment on board the CHAMP satellite. The observations from both Millstone Hill and Sondrestrom...

Mitochondria generate reactive oxygen species (ROS) dependent on substrate conditions, O(2) concentration, redox state, and activity of the mitochondrial complexes. It is well known that the FADH(2)-linked substrate succinate induces reverse electron flow to complex I of the electron transport chain and that this process generates superoxide (O(2)(*-)); these effects are blocked by the complex ...

Microbial fuel cells (MFCs) are processes used for simultanuous bioenergy capturing and waste treatment. In this study, a model for MFCs based upon a conduction mechanism for electron transfer is proposed, which integrates substrate utilization, current production and conduction and  microbial distribution and growth in batch flow mode. The outputs of the model and that of a mediator based mode...

Purple nonsulfur bacteria grow photoheterotrophically by using light for energy and organic compounds for carbon and electrons. Disrupting the activity of the CO2-fixing Calvin cycle enzyme, ribulose 1,5-bisphosphate carboxylase (RubisCO), prevents photoheterotrophic growth unless an electron acceptor is provided or if cells can dispose of electrons as H2. Such observations led to the long-stan...

A computational mechanistic model of superoxide (O2•-) formation in the mitochondrial electron transport chain (ETC) was developed to facilitate the quantitative analysis of factors controlling mitochondrial O2•- production and assist in the interpretation of experimental studies. The model takes into account all individual electron transfer reactions in Complexes I and III. The model accounts ...