Medler, Kathryn and Evanna L. Gleason. Mitochondrial Ca buffering regulates synaptic transmission between retinal amacrine cells. J Neurophysiol 87: 1426–1439, 2002; 10.1152/jn.00627.2001. The diverse functions of retinal amacrine cells are reliant on the physiological properties of their synapses. Here we examine the role of mitochondria as Ca buffering organelles in synaptic transmission betw...

The chemiosmotic coupling hypothesis for oxidative phosphorylation proposed by Mitchell1 postulates that electron transport along the respiratory chain in the mitochondrial membrane generates a transmembrane pH gradient, which becomes the immediate driving force for the enzymatic synthesis of adenosine 5'-triphosphate (ATP) from adenosine 5'-diphosphate (ADP) and phosphate through the reverse a...

Membrane vesicles prepared from Escherichia coli B/r grown on glutamate as a sole source of carbon and energy require sodium for glutamate accumulation when energized by D-lactate oxidation. Glutamate uptake can also be driven by a prearranged sodium gradient (out to in) in the absence of an energy source or a protonmotive force. Sodium ions are exchanged rapidly in respiring vesicles and the s...

The general secretion (Sec) pathway is a conserved essential pathway in bacteria and is the primary route of protein export across the cytoplasmic membrane. During protein export, the signal peptidase LepB catalyzes the cleavage of the signal peptide and subsequent release of mature proteins into the extracellular space. We developed a target-based whole cell assay to screen for potential inhib...

We carried out a series of experiment demonstrating the role of mitochondria in the cytosolic and mitochondrial Ca(2+) transients and compared the results with those from computer simulation. In rat ventricular myocytes, increasing the rate of stimulation (1~3 Hz) made both the diastolic and systolic [Ca(2+)] bigger in mitochondria as well as in cytosol. As L-type Ca(2+) channel has key influen...

The mechanism of proline entry into the matrix region of isolated corn mitochondria (Zea mays L. Mo17 x B73) was investigated by measuring osmotically induced changes of mitochondrial size (changes in A(520)) in combination with oxygen uptake measurements. Using NADH oxidation to generate the electrochemical gradient, we have determined that proline transport is stereospecific and that it can b...

Three novel thiosemicarbazone O-carboxymethyl chitosan derivatives were obtained via a condensation reaction of thiosemicarbazide O-carboxymethyl chitosan with o-hydroxybenzaldehyde, p-methoxybenzaldehyde, and p- chlorobenzaldehyde respectively. Their structures were characterized by elemental analysis, FTIR, (13)C NMR and X-ray diffraction. The antimicrobial behaviors of the prepared derivativ...

o-Xylylenebis (triphenylphosphonium peroxymonosulfate) (1) was easily prepared from an aqueous solution of oxone and o-xylylenebis- (triphenylphosphonium bromide). This Compound (1) is a useful and selective reagent for conversion of oximes, semicarbazones and phenylhydrazones to the corresponding carbonyl compounds. The reaction was carried out under solvent-free conditions and in the presence...

We have used phosphorus-31 nuclear magnetic resonance to determine intracellular pH in the cellular slime mold Dictyostelium discoideum. We devised an air-lift circulator to maintain the dense cell suspensions in a well-oxygenated and well-stirred state while causing minimal perturbation to the sample flowing through the detector coils. Cells continued to develop normally in this set-up. Spectr...