Various authors (1, 2, 3, 9) have reported that tritiated water as applied to plant roots does not fully exchange with water of various aerial organs, particularly leaves, even after long period of observation. This incomplete equality between tritium concentration in tissue water and external sources has been attributed to an inaccessible component of tissue water which does not exchange (2). ...

A balanced supply of essential nutrients is an important factor influencing root architecture in many plants, yet data related to the interactive effects of two nutrients on root growth are limited. Here, we investigated the interactive effect between phosphorus (P) and magnesium (Mg) on root growth of Arabidopsis grown in pH-buffered agar medium at different P and Mg levels. The results showed...

Wetlands seem to be especially vulnerable to invasions. Even though ≤6% of the earth’s land mass is wetland, 24% (8 of 33) of the world’s most invasive plants are wetland species. Furthermore, many wetland invaders form monotypes, which alter habitat structure, lower biodiversity (both number and “quality” of species), change nutrient cycling and productivity (often increasing it), and modify f...

The lingual artery of the bullfrog was perfused with artificial solution and the effects of Ca2+, Ca-channel blockers (MnCl2 and verapamil), cGMP, and cAMP added to the perfusing solution of the gustatory nerve responses were examined. The responses to chemical stimuli of group 1 (CaCl2, NaCl, distilled water, D-galactose, and L-threonine) applied to the tongue surface were greatly decreased by...

Na+ transport across the lamprey erythrocyte membrane was examined using 22Na as a tracer. Both Na+ influx and Na+ effux exhibit a wide variability among different lampreys due to amiloride-sensitive components. Addition of 1 mmol/l amiloride to incubation media resulted in a decrease of the Na+ influx from 8.4 +/- 0.9 to 5.5 +/- 0.3 mmol/l cells/h (n = 18, P < 0.001), and of the rate coefficie...

The effects of aluminum (Al) on sodium (Na) regulation by the freshwater crustacean Daphnia magna were determined. (22)Na influx and outflux experiments were conducted in soft water adjusted to pH 4.5, 5.0, and 6.5 (reference pH) with either ambient (0.02 mg/liter) or high (1.02 mg/liter) concentrations of total Al. The results indicate that Al toxicity was pH dependent. Aluminum increased the ...

The channel Orai1 requires Ca2+ store depletion in the endoplasmic reticulum and an interaction with the Ca2+ sensor STIM1 to mediate Ca2+ signaling. Alterations in Orai1-mediated Ca2+ influx have been linked to several pathological conditions including immunodeficiency, tubular myopathy, and cancer. We screened large-scale cancer genomics data sets for dysfunctional Orai1 mutants. Five of the ...

Parthenogenetic activation of Lytechinuspictus eggs can be monitored after inje&ion with the Ca-sensitive photoprotein aequorin to estimate calcium release during activation. Parthenogenetic treatments, including the nonelectrolyte urea, hypertonic sea water, and ionophore A23187, all acted to release Ca2+ from intracellular stores. Ionophore and urea solutions release Ca*’ from the same intrac...

1. In a preparation of human leucocytes maintained in tissue culture fluid, increasing the extracellular zinc concentration leads to a significant increase in both ouabain-sensitive sodium efflux and in sodium influx. 2. Cell water and sodium content do not alter significantly with increasing extracellular zinc concentration. 3. A small increase in the ouabain-insensitive sodium efflux can be d...