ISSN:
1573-5036
Keywords:
enzymatic isolation
;
K+ channel
;
patch clamp
;
xylem contact cells
;
Zea mays
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Because of their importance for nutrition, a method was developed to patch xylem contact cells in leaves of Vicia faba and maize. Since the lignification of older cells was a major obstacle for isolating protoplasts which could be patched, only young leaves (fourth fully developed leaf) were used. An important step in the isolation of these cells was the infiltration of the leaves and their exposure to enzymes for several hours, allowing mesophyll cells to be removed whilst having most of the xylem contact cells attached to the xylem. Channel activity in cell-attached mode or in excised patches could only be observed if an internal coating of sigmacote was used to block diffusion ions out of the pipette glass. Two different types of K+ channels were identified by measuring the reversal potential at different concentrations of KCl. One channel (SC) had a symmetric IV curve with a high probability of remaining open, irrespective of membrane potential; the other channel was an inward rectifier. The symmetical channel could be blocked weakly by Na+ but it was permeable to $${\text{NH}}_{{\text{4}}^{\text{ + }} } $$ .
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1004206208968
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