An antagonist of ATP-regulated potassium channels, the guanidine derivative U-37883A, stimulates the synthesis of phosphatidylserine in rat liver endoplasmic reticulum membranes

AbstractThe guanidine derivative U-37883A has been found to stimulate in vitro synthesis of phosphatidylserine in endoplasmic reticulum membranes, catalyzed exclusively by a serine-specific base exchange enzyme. The stimulation of the enzyme activity by the drug was concentration-dependent, with EC50 of 54 μM, while the biologically inactive analog of U-37883A, U-42069, was without effect. The stimulation caused by U-37883A was enhanced under the conditions when active transport of Ca2+ into the lumen of microsomal vesicles was induced, whereas it was inhibited by a calcium ionophore, A23187, and by a specific inhibitor of Ca2+-ATPase, thapsigargin. On the other hand, a potassium ionophore, valinomycin, had no effect on phosphatidylserine synthesis. U-37883A did not affect the Km of the base exchange enzyme for serine, but greatly reduced the EC50 value of the enzyme for calcium. Furthermore, Ca2+ uptake by endoplasmic reticulum vesicles has been found to increase in the presence of U-37883A. These observations suggest that U-37883A enhances phosphatidylserine synthesis indirectly by acting on calcium transport, thus affecting calcium concentration within the lumen of endoplasmic reticulum membranes. Alternatively, the effect of the drug could be propagated via the mechanism by which phospholipid flip-flop movement, known to regulate the serine-specific base exchange reaction, is modulated

Patterns of bilingual language use and response inhibition : a test of the adaptive control hypothesis

Given prior studies that provided inconsistent results, there is an ongoing debate on the issue of whether bilingualism benefits cognitive control. We tested the Adaptive Control Hypothesis, according to which only the intense use of different languages in the same situation without mixing them in single utterances (called dual-language context) confers a bilingual advantage in response inhibition. In a large-scale correlational study, we attempted to circumvent several pitfalls of previous research on the bilingual advantage by testing a relatively large sample of participants and employing a more reliable and valid measurement of constructs (i.e., latent variable approach accompanied by Bayesian estimation). Our results do not support the Adaptive Control Hypothesis' prediction: the intensity of the dual-language context experience was unrelated to the efficiency of response inhibition in bilinguals. The results suggest that the Adaptive Control Hypothesis is not likely to account for the inconsistent results regarding the bilingual advantage hypothesis, at least in the case of the response-inhibition mechanism. At the same time, the study points to the problem of measuring the response-inhibition construct at the behavioral level. No evidence for a robust response-inhibition construct adds to the growing skepticism on this issue in the literature

The Role of Biological Diversity in Agroecosystems and Organic Farming

Ecosystems are the basis of life and all human activities. Conservation of biological diversity is very important for the proper functioning of the ecosystem and for delivering ecosystem services. Maintaining high biodiversity in agroecosystems makes agricultural production more sustainable and economically viable. Agricultural biodiversity ensures, for example, pollination of crops, biological crop protection, maintenance of proper structure and fertility of soils, protection of soils against erosion, nutrient cycling, and control of water flow and distribution. The effects of the loss of biodiversity may not be immediately apparent, but they may increase the sensitivity of the ecosystems to various abiotic and biotic stresses. The combination of biodiversity conservation with profitable food production is one of the tasks of modern sustainable agriculture that faces the necessity of reconciling the productive, environmental, and social goals. As further intensification of production and increase in the use of chemical pesticides, fertilizers, and water to increase yields are increasingly criticized, global agriculture is looking for other biological and agrotechnical methods in order to meet the requirements of global food production

Ocena stopnia zrównoważenia gospodarstw rolnych o różnych kierunkach produkcji za pomocą modelu RISE

Model RISE (the Response-Inducing Sustainability Evaluation) jest narzędziem pozwalającym na kompleksową oceną stopnia zrównoważenia gospodarstw rolnych. Model ten uwzględnia ekologiczne, ekonomiczne oraz społeczne aspekty zrównoważenia gospodarstwa. W pracy przedstawiono wyniki oceny stopnia zrównoważenia trzech wybranych gospodarstw o różnych kierunkach produkcji (produkcja roślinna, zwierzęca i mieszana) z województwa lubelskiego. Badania wykazały, że żadnego z trzech porównywanych gospodarstw nie można uznać za zrównoważone według metodyki RISE. Wartości wskaźników w większości przypadków osiągały pozytywne wyniki, z wyjątkiem wskaźników „Różnorodność biologiczna i ochrona roślin”, „Warunki pracy” oraz „Zużycie wody”. Najbliższe osiągnięciu zrównoważenia było gospodarstwo o profilu produkcji roślinnej i wielostronnej. Najmniej korzystną ocenę zrównoważenia uzyskało gospodarstwo trzodowe. W żadnym gospodarstwie nie stwierdzono jednak poważnych problemów związanych z oceną ich stopnia zrównoważenia

Calcium Ions Regulate K+ Uptake into Brain Mitochondria: The Evidence for a Novel Potassium Channel

The mitochondrial response to changes of cytosolic calcium concentration has a strong impact on neuronal cell metabolism and viability. We observed that Ca2+ additions to isolated rat brain mitochondria induced in potassium ion containing media a mitochondrial membrane potential depolarization and an accompanying increase of mitochondrial respiration. These Ca2+ effects can be blocked by iberiotoxin and charybdotoxin, well known inhibitors of large conductance potassium channel (BKCa channel). Furthermore, NS1619 – a BKCa channel opener – induced potassium ion–specific effects on brain mitochondria similar to those induced by Ca2+. These findings suggest the presence of a calcium-activated, large conductance potassium channel (sensitive to charybdotoxin and NS1619), which was confirmed by reconstitution of the mitochondrial inner membrane into planar lipid bilayers. The conductance of the reconstituted channel was 265 pS under gradient (50/450 mM KCl) conditions. Its reversal potential was equal to 50 mV, which proved that the examined channel was cation-selective. We also observed immunoreactivity of anti-β4 subunit (of the BKCa channel) antibodies with ~26 kDa proteins of rat brain mitochondria. Immunohistochemical analysis confirmed the predominant occurrence of β4 subunit in neuronal mitochondria. We hypothesize that the mitochondrial BKCa channel represents a calcium sensor, which can contribute to neuronal signal transduction and survival

Jakość życia oraz jej predyktory wśród pacjentów neurologicznych — systematyczny przegląd badań

Quality of life is an important aspect in the fields of medicine and health sciences. It is presented as a complex concept. Therefore, it is presented in various ways. Its interpretation and definition depends mainly on the discipline and area of study. Very often, the quality of life is also defined in the context of the well-being that a person experiences during his life. It depends on the state of health. It can take into account a wide variety of problems, because neurological diseases bring about such unwanted effects as pain, the need for medical and rehabilitation stays, social isolation, and one of the worst consequences, i.e. shortening life expectancy. Therefore, it is important to conduct research on the quality of life among neurological patients. The results obtained from the conducted and continued research on large groups of patients could constitute a specific compendium of knowledge about the situation of patients, their needs and the perceived quality of life. Therefore, the aim of this study is to present research on the assessment of quality of life and its predictors among neurological patients. (JNNN 2020;9(3):114–118)Jakość życia jest ważnym aspektem w dziedzinie medycyny i nauk o zdrowiu. Ukazywana jest ona jako pojęcie złożone. Dlatego też prezentowana jest w różnorodny sposób. Jej interpretacja oraz definiowanie zależy w głównej mierze od dyscypliny i obszaru nauki. Bardzo często jakość życia definiowana jest także w kontekście dobrostanu jakiego człowiek doświadcza w ciągu swojego życia. Uwarunkowana jest ona od stanu zdrowia. Może uwzględniać dużą różnorodność problemów, ponieważ choroby neurologiczne przynoszą tak niechciane skutki jak ból, konieczność pobytów w placówkach medycznych oraz rehabilitacyjnych, izolację społeczną, oraz jedną z najgorszych konsekwencji, czyli skrócenie przewidywanej długości życia. Istotne jest zatem prowadzenie badań nad jakością życia wśród chorych neurologicznych. Uzyskane wyniki z prowadzonych oraz kontynuowanych badań na dużych grupach pacjentów mogłyby stanowić swoiste kompendium wiedzy na temat sytuacji chorych, ich potrzeb oraz odczuwanej jakości życia. Dlatego też celem prezentowanej pracy jest przedstawienie badań dotyczących oceny jakości życia oraz jej predyktorów wśród chorych neurologicznych. (PNN 2020;9(3):114–118

Bongkrekic acid and atractyloside inhibits chloride channels from mitochondrial membranes of rat heart

AbstractThe aim of this work was to characterize the effect of bongkrekic acid (BKA), atractyloside (ATR) and carboxyatractyloside (CAT) on single channel properties of chloride channels from mitochondria. Mitochondrial membranes isolated from a rat heart muscle were incorporated into a bilayer lipid membrane (BLM) and single chloride channel currents were measured in 250/50 mM KCl cis/trans solutions. BKA (1–100 μM), ATR and CAT (5–100 μM) inhibited the chloride channels in dose-dependent manner. The inhibitory effect of the BKA, ATR and CAT was pronounced from the trans side of a BLM and it increased with time and at negative voltages (trans–cis). These compounds did not influence the single channel amplitude, but decreased open dwell time of channels. The inhibitory effect of BKA, ATR and CAT on the mitochondrial chloride channel may help to explain some of their cellular and/or subcellular effects