Lacl3
Mostrando 25-36 de 37 artigos, teses e dissertações.
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25. Voltage-dependent intracellular pH in Helix aspersa neurones.
1. The intracellular pH (pHi) of large nerve cells from the mollusc, Helix aspersa, was measured with pH-sensitive micro-electrodes. Cells were held under voltage clamp and the effect on pHi of different holding potentials was determined. 2. Depolarization of the cell from the resting potential (about -50 mV) to -10 mV produced a fall in pHi that could be re
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26. Sodium current in single cells from bullfrog atrium: voltage dependence and ion transfer properties.
1. Whole-cell and patch-clamp techniques (Hamill, Marty, Neher, Sakmann & Sigworth, 1981) have been used to make quantitative measurements of the transient inward sodium current (INa) in single cells from bullfrog atrium. This preparation is particularly suitable for the study of INa: (i) the current density is relatively low, (ii) the cells lack a transvers
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27. Direct Measurement of Calcium Transport across Chloroplast Inner-Envelope Vesicles1
The initial rate of Ca2+ movement across the inner-envelope membrane of pea (Pisum sativum L.) chloroplasts was directly measured by stopped-flow spectrofluorometry using membrane vesicles loaded with the Ca2+-sensitive fluorophore fura-2. Calibration of fura-2 fluorescence was achieved by combining a ratiometric method with Ca2+-selective minielectrod
American Society of Plant Physiologists.
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28. Electrophysiological and chemical determination of acetylcholine release at the frog neuromuscular junction.
1. Mass fragmentography was used to measure the tissue content and release of acetylcholine (ACh) by frog sartorius muscles, which had been previously treated with an irreversible cholinesterase inhibitor. The frequency of miniature end-plate currents (m.e.p.c.s) was also measured. 2. Exposure of muscles for 15 min to 2 mM-LaCl3 resulted in a large release o
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29. Na+/Ca2+ exchange-mediated calcium entry in human lymphocytes.
Regulation of cytosolic Ca2+ and cytosolic Na+ is critical for lymphocyte cation homeostasis and function. To examine the influence of cytosolic Na+ on Ca2+ regulation in human peripheral blood lymphocytes, Ca2+ entry and cytosolic Ca2+ (measured with fura-2) were monitored in cells in which cytosolic Na+ was increased and/or the Na+ gradient was decreased b
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30. Transfer of synaptic vesicle antigens to the presynaptic plasma membrane during exocytosis.
We have utilized immunofluorescence techniques to look for synaptic vesicle antigens on the plasma membrane of resting and active nerve terminals. Rabbit antiserum was raised against purified cholinergic synaptic vesicles from the electric organ of Narcine brasiliensis, a marine electric ray. Antibodies to synaptic vesicles were shown to bind selectively to
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31. Regulation of lac Operon Expression: Reappraisal of the Theory of Catabolite Repression
The physiological state of Escherichia coli with respect to (permanent) catabolite repression was assessed by measuring the steady-state level of β-galactosidase in induced or in constitutive cells under a variety of growth conditions. Four results were obtained. (i) Catabolite repression had a major effect on fully induced or constitutive expression of the
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32. Membrane Changes and Adenosine Triphosphate Content in Normal and Malignant Transformed Cells
Transformed fibroblasts had a low content of ATP when grown at a high cell density and a high content of ATP when grown at a low cell density. Concanavalin A agglutinated transformed cells with a low, but not those with a high, ATP content. Transformed cells with a high ATP content gained agglutinability after ATP depletion by inhibitors of the energy-genera
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33. Lactose transport system of Streptococcus thermophilus: a hybrid protein with homology to the melibiose carrier and enzyme III of phosphoenolpyruvate-dependent phosphotransferase systems.
The gene responsible for the transport of lactose into Streptococcus thermophilus (lacS) was cloned in Escherichia coli as a 4.2-kilobase fragment from an EcoRI library of chromosomal DNA by using the vector pKK223-3. From deletion analysis, the gene for lactose transport mapped to two HindIII fragments with a total size of 2.8 kilobases. The gene was transc
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34. Electrophysiological Characterization of the Arabidopsis avrRpt2-Specific Hypersensitive Response in the Absence of Other Bacterial Signals1
The hypersensitive response (HR) is defined as rapid cell collapse at the infection site and often accompanies plant resistance. The physiological processes leading to HR are not well understood. Here, we report an electrophysiological characterization of bacterial HR caused by a single avirulence gene in the absence of other bacterial signals. We used dexam
American Society of Plant Biologists.
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35. Regulation of the gravitropic response and ethylene biosynthesis in gravistimulated snapdragon spikes by calcium chelators and ethylene inhibitors.
The possible involvement of Ca2+ as a second messenger in snapdragon (Antirrhinum majus L.) shoot gravitropism, as well as the role of ethylene in this bending response, were analyzed in terms of stem curvature and gravity-induced asymmetric ethylene production rates, ethylene-related metabolites, and invertase activity across the stem. Application of Ca2+ c
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36. Ionic permeabilities of the gill lamina cuticle of the crayfish, Astacus leptodactylus (E).
The cuticle of the gill lamina of the crayfish Astacus leptodactylus (E), mechanically isolated, was mounted in an Ussing chamber and examined for its electrical properties. The cuticle of the gill lamina obtained from exuviae had similar properties. When perfused with artificial fresh water (AFW) outside and Van Harreveld solution (VH) inside, the transcuti