Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the flagellate Euglena gracilis Klebs, gravitaxis is mediated by an active physiological receptor and is not the result of passive alignment of the cells in the water column. The threshold of this response was found at 0.08 < threshold < 0.16 g during a recent space flight on the American shuttle Columbia, where the cells were subjected to different accelerations between 0 and 1.5 g; the response saturated at 0.32 < saturation < or = 0.64 g. Over the whole duration of the mission no adaptation of the response to microgravity was observed. The whole body of the cell, rather than intracellular organelles, seems to act as statolith since suspending the cells in a density-adjusted medium (Ficoll) resulted in an inhibition of gravitaxis and even reversal of orientation at higher densities. Thus, the cytoplasm seems to exert a pressure on the respective lower membrane where it is hypothesized to activate stretch-sensitive specific ion channels, as indicated by inhibitor studies with gadolinium. One of the early steps in the sensory transduction chain seems to be a modulation of the membrane potential since ion-channel blockers, ionophores and ATPase inhibitors strongly inhibit gravitaxis in this flagellate without seriously affecting motility and phototaxis.
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PMID:Graviperception and graviorientation in flagellates. 1154 Mar 31

Transfer of Euglena gracilis Klebs Z cells from phototrophic to organotrophic growth on acetate results in derepression of the key enzymes of the glyoxylate cycle, malate synthase and isocitrate lyase, which appear coordinately regulated. The derepression of malate synthase and isocitrate lyase was accompanied by increased specific activities of succinate dehydrogenase, fumarase, and malate dehydrogenase, but hydroxypyruvate reductase activity was unaltered.Isolation of organelles from broken cell suspensions of cells grown heterotrophically on acetate was achieved by isopycnic centrifugation on sucrose gradients. Peaks of mitochondrial enzymes were obtained at equilibrium densities of 1.22 g cm(3) and 1.16 g cm(3), and although significant differences in the distribution of tricarboxylic acid cycle enzymes between these two peaks were not recorded adenosine triphosphatase activity was detected only in the less dense fraction (1.16 g cm(3)) showing this contained damaged mitochondria. The peak of particulate glyoxylate cycle enzymes was at an equilibrium density of 1.25 g cm(3), this being the same as that for glycolate pathway enzymes from phototrophic cells. Citrate synthase, isocitrate lyase, malate synthase, and malate dehydrogenase were all present in this fraction so it was concluded that Euglena glyoxysomes contain a complete glyoxylate cycle.
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PMID:Microbody-marker Enzymes during Transition from Phototrophic to Organotrophic Growth in Euglena. 1665 2