Comparative analysis of cytosolic and mitochondrial ATP synthesis in embryonic and postnatal hippocampal neuronal cultures

ATP in neurons is commonly believed to be synthesized mostly by mitochondria via oxidative phosphorylation. Neuronal mitochondria have been studied primarily in culture, i.e., in neurons isolated either from embryos or from neonatal pups. Although it is generally assumed that both embryonic and postnatal cultured neurons derive their ATP from mitochondrial oxidative phosphorylation, this has never been tested experimentally. We expressed the FRET-based ATP sensor AT1.03 in cultured hippocampal neurons isolated either from E17 to E18 rat embryos or from P1 to P2 rat pups and monitored [ATP]c simultaneously with mitochondrial membrane potential ΔΨm; TMRM) and NAD(P)H autofluorescence. In embryonic neurons, transient glucose deprivation induced a near-complete decrease in [ATP]c, which was partially reversible and was accelerated by inhibition of glycolysis with 2-deoxyglucose. In the absence of glucose, pyruvate did not cause any significant increase in [ATP]c in 84% of embryonic neurons, and inhibition of mitochondrial ATP synthase with oligomycin failed to decrease [ATP]c. Moreover, ΔΨm was significantly reduced by oligomycin, indicating that mitochondria acted as consumers rather than producers of ATP in embryonic neurons. In sharp contrast, in postnatal neurons pyruvate added during glucose deprivation significantly increased [ATP]c (by 54 ± 8%), whereas oligomycin induced a sharp decline in [ATP]c and increased ΔΨm. These signs of oxidative phosphorylation were observed in all tested P1-P2 neurons. Measurement of ΔΨm with the potential-sensitive probe JC-1 revealed that neuronal mitochondrial membrane potential was significantly reduced in embryonic cultures compared to the postnatal ones, possibly due to increased proton permeability of inner mitochondrial membrane. We conclude that, in embryonic, but not postnatal neuronal cultures, ATP synthesis is predominantly glycolytic and the oxidative phosphorylation-mediated synthesis of ATP by mitochondrial F1Fo-ATPase is insignificant. © 2013 Surin, Khiroug, Gorbacheva, Khodorov, Pinelis and Khiroug.Peer reviewe

Face reconstruction through active stereovision

The automatic face recognition is a very attractive problem and several solutions can be found in the literature . Most of them rely on the analysis of the images acquired by a classical CCD camera. These images are treated and given us input to a discrimination algorithm . However, the information contained in the image is relatively poor and it is very likely that these techniques will fail in the case of a large database with a lot of people . The surface of the faces is a very discriminant information so in this article, we propose a stereovision algorithm which can be used for the acquisition of the surface offaces . The problem of matching between the pattern and its images is solved using the epipolar constraint and the local coherency constraint . Some experimental results are shown .La reconnaissance automatique de visages est un problème qui suscite beaucoup d'intérêt et pour lequel divers algorithmes basés sur l'utilisation d'images acquises par des caméras CCD ont été proposés. L'information fournie aux algorithmes de discrimination mis en place dans ce type de solution est assez fruste et ces algorithmes sont peu susceptibles de fonctionner de manière robuste pour des bases comprenant un grand nombre d'individus. La surface du visage doit pouvoir être beaucoup plus discriminante. Dans cet article, nous proposons un algorithme de stéréovision active qui permet l'acquisition de surfaces de visages. Le problème de la mise en correspondance entre les éléments du motif projeté et leur image est résolu en utilisant la contrainte épipolaire et une contrainte de cohérence locale. Des résultats expérimentaux sont présentés

Measurements of light background at large depth in the ocean

The mean intensity of Cerenkov emission from the products of K(40) decay and bioluminescence was measured at depths to 5 km. The intensity of ocean light background is found to depend upon depth and at the 5 km level is equal on averaged to 300 + or - 60 quanta/sq cms into spatial angle of 2 pi sterradian in transparency window. The amplitudes, duration and number of BL flashes were measured at various depths. The intensive flashes due to BL are shown to be observed rather seldom at depths over 4 km

Physio-mechanical Materials Testing Using Scanning Contact Potentiometry Method

To study the processes of forming and growing embryonic fatigue cracks in steel EI-847 when tested under a uniaxial tension at constant load; adapting the method of scanning contact potentiometry using the INSTRON-5982 machine. The embryo was detected on the sample surface- in the yield point- and stably tracked by theequipment indications at higher loads up to the fracture point. Keywords: scanning contact potentiometry, electrical non-destructive testing, tension testing, fatigue crack, time-frequency signal analysis

Measurement of hadron cross sections with the SND detector

New results on exclusive hadron production in $e^+e^-$ annihilation obtained in experiments with the SND detector at the VEPP-2M and VEPP-2000 $e^+e^-$ colliders are presented.Comment: 4 pages, 4 figures, presented at the 14th International Workshop on Meson Production, Properties and Interaction (MESON 2016), Cracow, Poland, 2nd - 7th June 201