A teichuronopeptide (TUP) is one of major structural components of the cell wall of the facultative alkaliphilic strain Bacillus lentus C-125. A mutant defective in TUP synthesis grows slowly at alkaline pH. An upper limit of pH for growth of the mutant was 10.4, while that of the parental strain C-125 was 10.8. Gene tupA, directing synthesis of TUP, was cloned from C-125 chromosomal DNA. The p...

The pH in the cytoplasmic and thylakoid spaces of the blue-green alga, Anacystis nidulans, has been determined in the light and in the dark by uptake of 5,5-dimethyloxazolidine-2,4-dione and methylamine into the sucrose-impermeable (3)H-H(2)O space, as measured by silicon layer filtering centrifugation.Illumination causes an alkalinization in the cytoplasm which is accompanied by an acidificati...

Here we show for the first time that insulin increases the efficiency of the working heart by 35% through an increase in the free energy of the NADH dehydrogenase reaction, an equivalent increase in the cytosolic free energy of ATP hydrolysis and a decrease in O2 consumption. These changes in turn are linked to changes in the components of the tricarboxylic acid cycle and the potential and pH g...

In salt-tolerant Chara longifolia, enhanced Na+ efflux plays an important role in maintaining low cytoplasmic Na+. When it is cultured in fresh water (FW), C. longifolia has a higher Na+ efflux than the obligate FW Chara corallina, although pH dependence and inhibitor profiles are similar for both species (1. Whittington and M.A. Bisson 119941 j Exp Bot 45: 657-665). When it is cultured in salt...

Intracellular pH (pH(i)) was measured during the circadian cycle of Neurospora. Internal pH of Neurospora cultures in liquid medium was assayed by the 5,5-dimethyl-2,4-oxazolidinedione method and gave values for pH(i) which were similar to those previously obtained by other workers using pH-microelectrodes with agar-grown cultures. Cytoplasmic pH changed in liquid medium cultures, but these cha...

We tested the contribution of nucleoside triphosphate (NTP) hydrolysis, ethanol, and organic acid syntheses, and H(+)-pump ATPases activity in the acidosis of anoxic sycamore (Acer pseudoplatanus) plant cells. Culture cells were chosen to alter NTP pools and fermentation with specific nutrient media (phosphate [Pi]-deprived and adenine- or glycerol-supplied). In vivo (31)P- and (13)C-nuclear ma...

Cells of Bacillus firmus OF4 and Bacillus alcalophilus were examined by rapid-freeze freeze-fracture and freeze-substitution electron microscopy. No special vesicular structures linked to growth at alkaline pH were found, either within or associated with the cytoplasmic membrane. The cytoplasmic membranes of the alkaliphilic bacilli and the neutrophilic Bacillus subtilis BD99 were indistinguish...

Plasma membrane vesicles isolated by two-phase partitioning from the storage root of Beta vulgaris show atypically high water permeability that is equivalent only to those reported for active aquaporins in tonoplast or animal red cells (Pf=542 microm s(-1)). The values were determined from the shrinking kinetics measured by stopped-flow light scattering. This high Pf was only partially inhibite...

Methods for the simultaneous measurement of vacuolar and cytoplasmic pH in plant tissues currently have significant limitations. This study demonstrates the usefulness of methyl difluoro alanine (F2ALA) and methyl trifluoro alanine (F3ALA) with in-vivo F NMR spectroscopy to measure vacuolar and cytoplasmic pH in maize root tissue. The pH dependence of the chemical shift of F2ALA and F3ALA is gr...

The mineralocorticoid hormone aldosterone maintains acid-base balance and K+ homeostasis by regulating H+ and K+ secretory mechanisms in kidney epithelial cells. We have shown recently in the amphibian distal nephron that aldosterone activates a Na+/H+ exchange system in the luminal cell membrane, thus leading to transepithelial H+ secretion and cytoplasmic alkalinization. Since H+ secretory fl...