Allosteric Regulation of Na/Ca Exchange Current by Cytosolic Ca in Intact Cardiac Myocytes

The cardiac sarcolemmal Na-Ca exchanger (NCX) is allosterically regulated by [Ca]i such that when [Ca]i is low, NCX current (INCX) deactivates. In this study, we used membrane potential (Em) and INCX to control Ca entry into and Ca efflux from intact cardiac myocytes to investigate whether this allosteric regulation (Ca activation) occurs with [Ca]i in the physiological range. In the absence of Ca activation, the electrochemical effect of increasing [Ca]i would be to increase inward INCX (Ca efflux) and to decrease outward INCX. On the other hand, Ca activation would increase INCX in both directions. Thus, we attributed [Ca]i-dependent increases in outward INCX to allosteric regulation. Ca activation of INCX was observed in ferret myocytes but not in wild-type mouse myocytes, suggesting that Ca regulation of NCX may be species dependent. We also studied transgenic mouse myocytes overexpressing either normal canine NCX or this same canine NCX lacking Ca regulation (Δ680–685). Animals with the normal canine NCX transgene showed Ca activation, whereas animals with the mutant transgene did not, confirming the role of this region in the process. In native ferret cells and in mice with expressed canine NCX, allosteric regulation by Ca occurs under physiological conditions (KmCaAct = 125 ± 16 nM SEM ≈ resting [Ca]i). This, along with the observation that no delay was observed between measured [Ca]i and activation of INCX under our conditions, suggests that beat to beat changes in NCX function can occur in vivo. These changes in the INCX activation state may influence SR Ca load and resting [Ca]i, helping to fine tune Ca influx and efflux from cells under both normal and pathophysiological conditions. Our failure to observe Ca activation in mouse myocytes may be due to either the extent of Ca regulation or to a difference in KmCaAct from other species. Model predictions for Ca activation, on which our estimates of KmCaAct are based, confirm that Ca activation strongly influences outward INCX, explaining why it increases rather than declines with increasing [Ca]i

Anion-transport mechanism of a triazole-bearing derivative of prodigiosine: a candidate for cystic fibrosis therapy

Cystic fibrosis (CF) is a genetic lethal disease, originated from the defective function of the CFTR protein, a chloride and bicarbonate permeable transmembrane channel. CF mutations affect CFTR protein through a variety of molecular mechanisms which result in different functional defects. Current therapeutic approaches are targeted to specific groups of patients that share a common functional defect. We seek to develop an innovative therapeutic approach for the treatment of CF using anionophores, small molecules that facilitate the transmembrane transport of anions. We have characterized the anion transport mechanism of a synthetic molecule based on the structure of prodigiosine, a red pigment produced by bacteria. Anionophore-driven chloride efflux from large unilamellar vesicles is consistent with activity of an uniporter carrier that facilitates the transport of anions through lipid membranes down the electrochemical gradient. There are no evidences of transport coupling with protons. The selectivity sequence of the prodigiosin inspired EH160 ionophore is formate > acetate > nitrate > chloride > bicarbonate. Sulfate, phosphate, aspartate, isothionate, and gluconate are not significantly transported by these anionophores. Protonation at acidic pH is important for the transport capacity of the anionophore. This prodigiosin derived ionophore induces anion transport in living cells. Its low toxicity and capacity to transport chloride and bicarbonate, when applied at low concentration, constitute a promising starting point for the development of drug candidates for CF therapy.European Union’s Horizon 2020 research and innovation programme under grant agreement No 667079 and Consejería de Educación de la Junta de Castilla y León (Project BU092U16)

Analysis of Amino Acids in Aqueous Solution of Honey and Honey Wines

This study explores the influence of amino acids released during pollen fermentation on the sensory attributes of honey wine. Fermented and non-fermented pollen were introduced into a 20% aqueous honey solution prior to alcoholic fermentation. Analysis revealed a decrease in amino acid levels post-fermentation, accompanied by an increase in higher alcohols, ethers, and acetaldehydes compared to the control. Notably, honey wine fermented with fermented flower pollen exhibited heightened volatile substance content, enhancing its taste and aroma profile. These findings underscore the significant role of pollen fermentation in shaping the sensory characteristics of honey wine

Analysis of Amino Acids in Aqueous Solution of Honey and Honey Wines

This study explores the influence of amino acids released during pollen fermentation on the sensory attributes of honey wine. Fermented and non-fermented pollen were introduced into a 20% aqueous honey solution prior to alcoholic fermentation. Analysis revealed a decrease in amino acid levels post-fermentation, accompanied by an increase in higher alcohols, ethers, and acetaldehydes compared to the control. Notably, honey wine fermented with fermented flower pollen exhibited heightened volatile substance content, enhancing its taste and aroma profile. These findings underscore the significant role of pollen fermentation in shaping the sensory characteristics of honey wine

Photobiosynthesis of Isoprene and Dependence thereof on Functioning of Electron-Transport Chain of Chloroplasts

Available from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

THE RESEARCH OF OPTIMAL CONDITIONS FOR SAFRANAL EXTRACTION FROM SAFFRON FLOWER

Saffron flower on different stages of its physiological development contains important biologically active compounds (including: protocrocine, picrocrocine, crocine, safranal), which can affect on human organism and it is important to use saffron in food technologies. Use of saffron in folk medicine has a huge background. It was used to cure around 70 illness and what is the most important, it was used to prevent and treat heart diseases. This effect is typical for safranal, which is synthesized and accumulated during the flower drying process. In this article the following issues are discussed: the process of safranal extraction, optimal conditions of this process and the results of extract analysis

Determination Of The Thyme Harvesting Period According To The Content Of The Protocrocin

Thyme is one-year-old scented grass. It has a great deal of use in the kitchen of various countries, as a spice because it is distinguished by its taste and aroma. Thyme is used in pharmacy, which is caused by the fact that it contains Carotenoid glycosides. Thyme is widely used in the production of alcoholic and non-alcoholic drinks to

DYNAMICS OF ACCUMULATION OF HIGHER ALCOHOL-TYROSOL IN THE PROCESS OF ALCOHOLIC FERMENTATION OF HONEY SWEET

Alcoholic fermentation is a crucial process of making a drink. Honey wine differs from other alcoholic beverages by its specific honey aroma and taste, the organoleptic properties of which determine the quality of the product. Honey wine contains volatile components along with other substances: ethers and higher alcohols, which differ from each other in their organoleptic properties and can have different effects on the taste and aroma of the product. Higher alcohols are derived from amino acids in various ways (derived from raw materials, as well as obtained by chemical and biochemical transformations of various substances); the amino acid tyrosine is converted during the alcoholic fermentation process to form the aromatic alcohol tyrosol. The latter is characterized by the smell of honey and candle. Based on the above, we aimed to study tyrosol in our research facilities. To determine the dynamics of the accumulation of higher alcohol-tyrosol in the process of alcoholic fermentation of honey sweet, we used: paper chromatographic method for qualitative analysis, and spectrophotometric method for tyrosol quantification. It has been found that the most abundant alcohol with the smell and taste of honey - tyrosol, is present in small amounts in honey and is found in relatively large quantities in the product obtained from its alcoholic fermentation - honey wine