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A fluorimetric assay using ethidium bromide (EB) was employed to quantify cell death in monolayer cell cultures (MA-104 cells) in situ and isolated cell suspensions (isolated colonic cells and Leishmania). Fluorescence of EB stained cells was measured with a photometer coupled to an inverted microscope for cell monolayers or in a spectrofluorometer for cell(More)
Rotavirus matures inside the endoplasmic reticulum (ER), a site of intracellular calcium storage. Total cell Ca2+ depletion has been shown to impair virus maturation, arresting this process at the membrane-enveloped intermediate form following its budding into the ER. On the other hand, rotavirus infection leads to an increase in the internal Ca2+(More)
Rotavirus infection modifies Ca(2+) homeostasis, provoking an increase in Ca(2+) permeation, the cytoplasmic Ca(2+) concentration ([Ca(2+)](cyto)), and total Ca(2+) pools and a decrease in Ca(2+) response to agonists. A glycosylated viral protein(s), NSP4 and/or VP7, may be responsible for these effects. HT29 or Cos-7 cells were infected by the SA11 clone(More)
Rotavirus infection of cultured cells induces a progressive increase in plasma membrane permeability to Ca2+. The viral product responsible for this effect is not known. We have used tunicamycin and brefeldin A to prevent glycosylation and membrane traffic and study the involvement of viral glycoproteins, NSP4 and/or VP7, in rotavirus-infected HT29 and(More)
The mechanism by which rotavirus and other nonenveloped viruses enter the cell is still not clear. We have proposed an endocytosis model where the critical step for virus uncoating and membrane permeabilization is the decrease in Ca(2+) concentration in the endosome. In this paper, we monitored rotavirus entry by measuring alpha-sarcin-rotavirus coentry and(More)
Some viruses induce changes in membrane permeability during infection. We have shown previously that the porcine strain of rotavirus, OSU, induced an increase in the permeability to Na+, K+, and Ca2+ during replication in MA104 cells. In this work, we have characterized the divalent cation entry pathway by measuring intracellular Ca2+ in fura-2-loaded MA104(More)
Rotavirus infection modifies the metabolism and ionic homeostasis of the host cell. First, there is an induction of viral synthesis with a parallel shutoff of cell protein production, followed by an increase of plasma membrane Ca2+ permeability, thereby inducing an increase of free cytoplasmic and sequestered Ca2+ concentrations. Cell death follows at a(More)
The concentration and localization of serotonin was determined in the retina of the teleost Eugerres plumieri by using high performance liquid chromatography (HPLC) and immunohistochemical techniques. Serotonin and dopamine were measured simultaneously, their concentrations in the retina being 77 +/- 8 and 516 +/- 23 ng/mg tissue respectively. Treatment of(More)
Rotavirus infection is characterized by a number of Ca(2+) dependent virus-cell interactions. The structure of rotavirus triple-layered particles (TLP) is dependent on Ca(2+) concentration. Acquisition of the capsid outer layer requires a high Ca(2+) concentration inside the ER. Infection modifies Ca(2+) homeostasis of the cell, increasing ER Ca(2+)(More)
Rotavirus infection modifies Ca(2+) homeostasis provoking an increase in Ca(2+) permeation, cytoplasmic Ca(2+) concentration ([Ca(2+)](cyto)), total Ca(2+) pools and, a decrease of Ca(2+) response to agonists. These effects are mediated by NSP4. The mechanism by which NSP4 deranges Ca(2+) homeostasis is not yet known. It has been proposed that the increase(More)
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