ABSTRACT
Microvascular endothelial cells involved in angiogenesis are exposed to an acidic environment that is not conducive for growth and survival. These cells must exhibit a dynamic intracellular (cytosolic) pH (pHcyt) regulatory mechanism to cope with acidosis, in addition to the ubiquitous Na+/H+ exchanger and HCO3--based H+-transporting systems. We hypothesize that the presence of plasmalemmal vacuolar-type proton ATPases (pmV-ATPases) allows microvascular endothelial cells to better cope with this acidic environment and that pmV-ATPases are required for cell migration. This study indicates that microvascular endothelial cells, which are more migratory than macrovascular endothelial cells, express pmV-ATPases. Spectral imaging microscopy indicates a more alkaline pHcyt at the leading than at the lagging edge of microvascular endothelial cells. Treatment of microvascular endothelial cells with V-ATPase inhibitors decreases the proton fluxes via pmV-ATPases and cell migration. These data suggest that pmV-ATPases are essential for pHcyt regulation and cell migration in microvascular endothelial cells.
Subject(s)
Cell Membrane/enzymology , Cell Movement/physiology , Endothelium, Vascular/physiology , Vacuolar Proton-Translocating ATPases/metabolism , Animals , Cell Membrane/physiology , Cells, Cultured , Endothelium, Vascular/cytology , Endothelium, Vascular/enzymology , Hydrogen-Ion Concentration , Immunohistochemistry , Microcirculation/physiology , Rats , Rats, Inbred BB , Sodium-Hydrogen Exchangers/physiologyABSTRACT
Interrelationship between phosphorylation of plasmatic membrane proteins in brain cells and the rate of mice encephalomyocarditis virus adsorption was studied. Phosphorylation of proteins induced by dsRNA (laryphane) was most distinctly manifested in membrane fraction and cytosol of rat brain neuronal cells. Similarity of molecular mass spectra in dsRNA- and cAMP-dependent phosphorylation enabled to suggest that dsRNA activated protein kinase. An increase in the rate of plasmatic membrane proteins phosphorylation appears to correlate with inhibition of virus adsorption as shown by studies of these reactions dynamics. Under conditions of considerable increase in the rate of membrane proteins phosphorylation adsorption of virus on cells was distinctly inhibited.
Subject(s)
Brain/metabolism , Encephalomyocarditis virus/drug effects , Interferon Inducers/pharmacology , Membrane Proteins/metabolism , RNA, Double-Stranded/pharmacology , Adsorption , Animals , Encephalomyocarditis virus/metabolism , L Cells , Mice , Phosphorylation , Protein Kinases/metabolismABSTRACT
Physico-chemical characteristics of plasmid DNAs isoalted from Pseudomonas putida G7 were studied as well as the behavior of these DNAs in th eourse of chromatography on columns with Sepharose 4B and kieselguhr with methylated albumin (MAC). This strain was found to contain several plasmid DNAs having molecular weights of 33-36X10(6), 15-18X10(6), and 3-5X10(6) dalton. The plasmid DNAs of biodegradation are supposed to be located in the vicinity of chromosomes, and only a small part of them is characterized by extrachromosomal localization.
Subject(s)
DNA, Bacterial/analysis , Plasmids , Pseudomonas/analysis , Chemical Phenomena , Chemistry, Physical , Chromatography , Chromatography, Agarose , Diatomaceous Earth , Microscopy, Electron , Molecular Weight , Pseudomonas/geneticsABSTRACT
Localization of Sendai virus 50S RNA in Ehrlich ascitic carcinoma cells was studied. At 48 hours postinfection virus-specific 50S RNA was found in the nucleus after 30 min exposure to 3H-uridine, and its amount increased after 1-hour exposure to the precursor reaching 18% of the total nucleus virus-specific RNA. After 2-hour or longer exposure to the precursor the amount of 50S RNA in the nuclei decreased considerably and in the cytoplasm in this gradient region a considerable radioactivity appeared. Rapid utilization of 3H-uridine by the cells under these experimental conditions suggests that 50S RNA is synthesized in the nucleus and migrates to the cytoplasm.
Subject(s)
Parainfluenza Virus 1, Human/growth & development , RNA, Viral/biosynthesis , Virus Replication , Animals , Carcinoma, Ehrlich Tumor , Cell Nucleus/metabolism , Cells, Cultured/metabolism , Cytoplasm/metabolismABSTRACT
Virus-specific structures with sedimentation coefficients of 250-300, 200 and 150 S were isolated from the polysome fraction of Sendai virus-infected Ahrlich ascitic carcinoma cells treated with cycloheximide, at early stages of infection (1.5 to 2 hours after inoculation). All these 3 types of structure contained both parental and newly synthesized viral RNA. RNA extracted from these structures consisted of 2 components sedimenting in sucrose density gradients in the zones of 50-70 and 35-40 S. Both components contained parental and newly synthesized RNA and were partially resistant to ribonuclease. RNA extracted from rapidly sedimenting structures (250-300 S) contained mainly the 50-70 S component; RNA recovered from 200 S structures contained the 35-40 S component. By analogy with reported data, the isolated forms of RNA have been characterized as transcriptive intermediates.
