Correction of contractile function and metabolism in canine ischemic myocardium due to exogenous glutamic acid

The effect of intravenous glutamic acid infusion (3 mg/kg/min) was studied during myocardial ischemia and reperfusion in anesthetized dogs. Left ventricular ischemia was induced by underperfusion of the anterior descending and circumflex coronary arteries. Glutamic acid reduced the ischemic contractile depression 2 min after a 60%-reduction of the coronary blood flow. The left ventricular systolic pressure was decreased by 9% versus 22%, dP/dt by 16% versus 29%, left ventricular systolic pressure heart rate product by 16% versus 31%. Reperfusion with glutamic acid improved the recovery of cardiac performance without any increase in myocardial oxygen consumption. Glutamic acid infusion resulted in a 2-fold augmentation of glutamate uptake by the ischemic myocardium. It led to cessation of ammonia release by the heart due to activation of glutamine synthesis, enhancement of alanine formation coupled with pyruvate utilization and did not change lactate production. The mechanisms of the protective action of glutamic acid are discussed.     

Changes in ornithine decarboxylase activity in the developing parotid salivary gland

Ornithine decarboxylase activity in the rat parotid salivary gland was estimated during the early postnatal development. Regular alterations of enzymatic activity were found in different periods of gland development. The data obtained were compared with the evidence on the establishment of protein synthesis circahoralian rhythm of this organ in ontogenesis. The ornithine decarboxylase activity, being rather high in the parotid gland as long as up to the 20th-21st days, decreases during the termination of differentiation in this organ. It rises simultaneously with the emergence of circahoralian rhythm of protein synthesis.     

At the beginning of the route: ABA perception and signal transduction in plants

Nowadays, fundamentally important data toward the molecular mechanisms of phytohormone action, starting from hormonal signal perception and up to changes in hormone-regulated gene expression, became available. Signaling mechanisms for plant cell responses to ABA remained the least known. Although a substantial progress was achieved in our understanding of the role of protein kinases and protein phosphatases functioning downstream receptors, identification of ABA receptors has induced very hot debates. This review summarizes information obtained during the last decade and concerned the molecular mechanisms of perception and signal transduction of ABA signal in plants.     

Evolution of raw meat polarization-based properties by means of Mueller matrix imaging

The possibilities of using Mueller matrix (MM) imaging polarimetry to assess meat quality have not yet been sufficiently explored. In the current study, the fresh porcine muscles are imaged at room temperature with a wide-field MM imaging polarimeter over 26 hours to visualize dynamics of tissue optical properties through applying Lu-Chipman decomposition. The frequency distribution histograms (FDHs) and statistical analysis of the MM elements show prominent changes over time. The wavelength spectra of both total depolarization and scalar retardance have dips at 550 nm whereas their values continuously increase with time; the former is referred to the increase of number of scattering events and decrease of myoglobin absorption in the red part of visible spectra related to meat color and freshness, while the latter is associated with the increase in birefringence and meat tenderness. The obtained results are promising to develop a novel fast noncontact optical technique for monitoring of meat quality.     

The effect of lipase from Penicillium sp. on the membrane fraction of the levorin-producing Streptomyces levoris

The effect of a lipase preparation from Penicillium sp. on the membranes of the levorin producer Streptomyces levoris was being studied. The enzyme preparation was found preferably to hydrolyse neutral lipids in the Str. levoris membranes, which makes it possible to use the lipase from Penicillium sp. for studying neutral lipids in microbial membranes.     

Possible mechanisms of the formation of structures in bacterial populations consisting of motile cells

The formation of fixed and moving structures was studied in Escherichia coli populations. The moving and fixed structures were shown to be formed only by bacteria with a taxis system. The moving structures caused an uneven distribution of the substrate concentration. Bacterial growth on agar with the unevenly distributed substrate led to the appearance of fixed structures. Mechanisms responsible for the formation of bacterial structures remain obscure.