Fischer (I ) proposes that his results "strongly suggest that the basic mechanism of stomatal opening, in response to light plus CO2-free air, is stimulation of the uptake of potassium." I believe that his evidence supports the opposite conclusion (2) that "in order to account for stomatal opening, the guard cells would have to absorb 13 times as rapidly as the most rapidly absorbing cells." Fi...

The ability of plants to absorb ions selectively is a major reason for the preference for chemical rather than physical theories of ion uptake (11), yet in spite of this, comparatively little attention has been paid to this property. Thus far, selectivity between alkali cations has been examined in excised barley roots (6) in beet discs (12) and in whole plants (1,4). In recent years the relati...

Hydroponically grown ten grape genotypes (Vitis vinifera L.) were treated with different concentrations of NaCl. Chawga genotype accumulated K+ in its root and shoot even at high salinity. The correlation between Na+ and K+ concentrations in root and lamina of all genotypes was negative (P

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...

In cardiomyocytes, connexin 43 (Cx43) forms gap junctions and unopposed hemichannels at the plasma membrane, but the protein is also present at the inner membrane of subsarcolemmal mitochondria (SSM). Both inhibition and genetic ablation of Cx43 reduce ADP-stimulated complex 1 respiration. Since mitochondrial potassium influx impacts on oxygen consumption, we investigated whether or not inhibit...

oocyte]. Oocytes were incubated for 24 to 48 hours, treated with coelenterazine [10 ,uM coelenterazine (Molecular Probes, Eugene, OR) and 30 p.M reduced glutathione in OR-2 media (no calcium)] for 2 to 3 hours with gentle orbital shaking in the dark at 18°C, and retumed to ND-86 medium with calcium (maintained in the dark with shaking) until measurements were initiated. For luminometer measurem...

Potassium transport characteristics were investigated in three species of freshwater bivalves: a corbiculid, Corbiculafluminea, and two unionids, Carunculina texasensis and Ligumia subrostrata. Using K, all three were found to take up potassium from dilute artificial pondwater ([K] about O.OSmmolP). The influx (7i) was 0.72/iequivg"drytissueh^ in the corbiculid, significantly higher than the va...

The inward transport of potassium by separated dog erythrocytes has been studied at concentrations of potassium in the medium from 2.9 to 25.0 m.eq./liter and at 38.0 and 33.0 degrees C. At the physiological concentration of external potassium (4.06 m.eq./liter medium), the inward potassium flux is 0.11 m.eq./liter cells hour and the glucose consumption is 2.0 mM/liter cells hour. The dependenc...