Cytosolic calcium levels and stress induced y-amino butyrate synthesis in asparagus mesophyll cells
dc.contributor.author | Cholewa, Ewa M. | en_US |
dc.date.accessioned | 2009-07-09T17:34:38Z | |
dc.date.available | 2009-07-09T17:34:38Z | |
dc.date.issued | 1995-07-09T17:34:38Z | |
dc.identifier.uri | http://hdl.handle.net/10464/1819 | |
dc.description.abstract | Numerous 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.iso | eng | en_US |
dc.publisher | Brock University | en_US |
dc.subject | Calmodulin. | en_US |
dc.subject | Cytosol. | en_US |
dc.subject | Aminobutyric acid. | en_US |
dc.subject | Asparagus--Cytochemistry. | en_US |
dc.title | Cytosolic calcium levels and stress induced y-amino butyrate synthesis in asparagus mesophyll cells | en_US |
dc.type | Electronic Thesis or Dissertation | en |
dc.degree.name | M.Sc. Biological Sciences | en_US |
dc.degree.level | Masters | en_US |
dc.contributor.department | Department of Biological Sciences | en_US |
dc.degree.discipline | Faculty of Mathematics and Science | en_US |
refterms.dateFOA | 2021-07-16T11:12:08Z |