We studied the effect of norepinephrine, calcium concentration, and rate of discharge in the presence of different [Ca2+]0 on radioactive potassium movements in cardiac Purkinje fibers. The following results were obtained: (1) norepinephrine increases potassium uptake in quiescent fibers and in fibers driven at constant rate, but more in the latter; (2) norepinephrine also increases potassium u...

We studied the effect of norepinephrine, calcium concentration, and rate of discharge in the presence of different |Ca * ],, on radioactive potassium movements in cardiac Purkinje fibers. The following results were obtained: (1) norepinephrine increases potassium uptake in quiescent fibers and in fibers driven at constant rate, but more in the latter; (2) norepinephrine also increases potassium...

To probe the mechanism by which intracellular ATP, Na+, and Cl- influence the activity of the NaK2Cl cotransporter, we measured bumetanide-sensitive (BS) 86Rb fluxes in the osteosarcoma cell line UMR-106-01. Under physiological gradients of Na+, K+, and Cl-, depleting cellular ATP by incubation with deoxyglucose and antimycin A (DOG/AA) for 20 min at 37 degrees C reduced BS 86Rb uptake from 6 t...

As a leading cause of community-associated and nosocomial infections, Staphylococcus aureus requires sophisticated mechanisms that function to maintain cellular homeostasis in response to its exposure to changing environmental conditions. The adaptation to stress and maintenance of homeostasis depend largely on membrane activity, including supporting electrochemical gradients and synthesis of A...

All living cells have an absolute requirement for K+, which must be taken up from the external medium. In contrast to marine organisms, which live in a medium with an inexhaustible supply of K+, terrestrial life evolved in oligotrophic environments where the low supply of K+ limited the growth of colonizing plants. In these limiting conditions Na+ could substitute for K+ in some cellular functi...

A field experiment was carried out in the Light village of Netrokona Sadar during the period from December 2010 to March 2011 to study the performance of some wheat varieties in terms of nutrient contents and their uptake. The experiment comprised of five varieties of wheat viz. BARI Gam 25, Shatabdi, BARI Gam 26, Prodip and Bijoy. The experiment was laid out in a randomized complete block desi...

Maintenance of intracellular K(+) concentrations that are not growth-limiting, in an environment of high Na(+), is characteristic of NaCl-adapted cells of the glycophyte, tobacco (Nicotiana tabacum/gossii). These cells exhibited a substantially greater uptake of (86)Rb(+) (i.e. an indicator of K(+)) relative to unadapted cells. Potassium uptake into NaCl-adapted cells was 1.5-fold greater than ...

Two ionophores (monensin and gramicidin) that carry Na+ into 3T3 cells markedly enhance the rate of 86Rb+ uptake. Ouabain prevents both ionophores from increasing 86Rb+ uptake, indicating that the ionophores activate the Na+,K+ pump. Measurements of 86Rb+ uptake and cell Na+ and K+ over a range of monensin concentrations show that the activity of the Na+,K+ pump in 3T3 cells is limited by the s...

abstract heated micaceous minerals under different commercial brand names (including vermiculite) are used as culture medium in greenhouses. heating minerals affects the release of elements, such as potassium, by changing their structure. the present study, investigates the ability of alfalfa, as one of the most important fodder around the world, to take up the non-exchangeable and structural p...