The minor receptor group human rhinovirus type 2 enters host cells by endocytosis via members of the low-density-lipoprotein receptor family. In late endosomes, it undergoes a conformational change solely induced by a pH of < or =5.6, resulting in RNA transfer across the endosomal membrane into the cytoplasm. To determine potential driving forces of this process, we investigated whether RNA pen...

BACKGROUND AND PURPOSE Symptomatic hemorrhagic transformation (HT) is the most important complicating factor after treatment with intravenous tissue plasminogen activator. In this study, we used multimodal magnetic resonance imaging to investigate the incidence and severity of reperfusion-based HT in spontaneously hypertensive rats after ischemia/reperfusion. METHODS Twenty male spontaneously...

The outermost epidermal layer, the stratum corneum (SC), exhibits an acidic surface pH, whereas the pH at its base approaches neutrality. NHE1 is the only Na(+)/H(+) antiporter isoform in keratinocytes and epidermis, and has been shown to regulate intracellular pH. We now demonstrate a novel function for NHE1, as we find that it also controls acidification of extracellular "microdomains" in the...

Using pH-sensitive microelectrodes (in vitro) and acridine orange photometry (in vivo), the actions of the two tonoplast phosphatases, the tp-ATPase and the tp-PPase, were investigated with respect to how effectively they could generate a transtonoplast pH-gradient. Under standard conditions the vacuoles of the aquatic liverwort Riccia fluitans have an in vivo pH of 4.7 to 5.0. In isolated vacu...

Membrane vesicles of Clostridium thermoautotrophicum containing carbon monoxide dehydrogenase generated a proton motive force when exposed to CO. This proton motive force, with a value of -140 mV, consisted of only an electrical potential at pH 7.5 and above and of an electrical potential and pH gradient at a lower pH. The proton motive force drove the uptake of L-alanine by the vesicles to a c...

ATP, the universal carrier of cell energy, is manufactured from ADP and phosphate by the enzyme ATP synthase using the free energy of an electrochemical gradient of protons (or Na(+)). The proton-motive force consists of two components, the transmembrane proton concentration gradient (delta pH) and the membrane potential. The two components were considered to be not only thermodynamically but a...

The xanthophyll cycle-dependent dissipation of excitation energy in higher plants is one of the most important regulatory and photoprotective mechanisms in photosynthesis. Using parallel time-resolved and pulse-amplitude modulation fluorometry, we studied the influence of the intrathylakoid pH and the xanthophyll cycle carotenoids on the PSII chlorophyll (Chl) a fluorescence yield in thylakoids...

The generation of a proton gradient across the inner mitochondrial membrane (IMM) is an essential energy conservation event that couples the oxidation of carbohydrates and fat to the synthesis of ATP. Studies in isolated mitochondria have established that the chemical gradient for protons (pH m) and the mitochondrial membrane potential ( m) contribute independently to the proton-motive force...

Rewarding properties of psychostimulants result from reduced uptake and/or increased release of dopamine at mesolimbic synapses. As exemplified by cocaine, many psychostimulants act by binding to the dopamine uptake transporter. However, this does not explain the action of other psychostimulants, including amphetamine. As most psychostimulants are weak bases and dopamine uptake into synaptic ve...

Previous studies have suggested that pulmonary hypertension (PH) in severe aortic stenosis (AS) is a risk factor for operative mortality with aortic valve replacement (AVR). Conversely, others have shown that patients with AS and PH extract a large symptomatic and survival benefit from AVR compared with those patients not treated surgically. We sought to evaluate the prevalence, severity, and m...