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dc.contributor.authorCholewa, Ewa M.en_US
dc.date.accessioned2009-07-09T17:34:38Z
dc.date.available2009-07-09T17:34:38Z
dc.date.issued1995-07-09T17:34:38Z
dc.identifier.urihttp://hdl.handle.net/10464/1819
dc.description.abstractNumerous investigations have demonstrated large increases in y-amino butyrate (GABA) levels in response to a variety of stresses such as touch or cold shock (Wallace et ale 1984) Circumstantial evidence indicating a role of Ca2 + in these increases includes elevated Ca2+ levels in response to touch and cold shock (Knight et ale 1991), and the demonstration of a calmodulin binding domain on glutamate decarboxylase (GAD), the enzyme responsible for GABA synthesis (Baum et al 1993) In the present study the possible role of Ca2+ and calmodulin in stimulation of GAD and subsequent GABA accumulation was examined using asparagus mesophyll cells. Images of cells loaded with the Ca2+ indicator Fluo-3 revealed a rapid and transient increase in cytosolic Ca2+ in response to cold shock. GABA levels increased by 106% within 15 min. of cold shock. This increase was inhibited 70% by the calmodulin antagonist W7, and 42% by the Ca2+ channel blocker La3+.. Artificial elevation of intracellular Ca2+ by the Ca2+ionophore A23187 resulted in an 61% increase in GABA levels. Stimulation of GABA synthesis by ABA resulted in an 83% increase in GABA levels which was inhibited 55% by W7. These results support the hypothesis that cold shock stimulates Ca2+ entry into the cytosol of the cells which results in Ca2+/calmodulin mediated activation of GAD and consequent GABA synthesis.en_US
dc.language.isoengen_US
dc.publisherBrock Universityen_US
dc.subjectCalmodulin.en_US
dc.subjectCytosol.en_US
dc.subjectAminobutyric acid.en_US
dc.subjectAsparagus--Cytochemistry.en_US
dc.titleCytosolic calcium levels and stress induced y-amino butyrate synthesis in asparagus mesophyll cellsen_US
dc.typeElectronic Thesis or Dissertationen_US
dc.degree.nameM.Sc. Biological Sciencesen_US
dc.degree.levelMastersen_US
dc.contributor.departmentDepartment of Biological Sciencesen_US
dc.degree.disciplineFaculty of Mathematics and Scienceen_US
refterms.dateFOA2021-07-16T11:12:08Z


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