Biological Applications with the NVPi

humming bird logo Biological Applications of the NVPi


A Calcium Flux is Found Exiting All Cells that Have Been Examined, details. The following model has been proposed and is being tested.

Ion probe

Three components of Ca++ efflux:


Fact One The [K]i is greater than [K]o and results in a high positive potential outside the cell.
Fact Two The [Ca]o is greater than [Ca]i and in combination with a highly positive membrane potential results in a high pressure for calcium to enter the cell when a channel opens briefly.
Fact Three The [Ca]i rises to a point at which pumps are activated to expel it outside the cell.


Model of a calcium sink at the tip of a plant root hair,

Ion probe
details of Root Hair Model.

Ion probe 3-D Kinemage plot of Proton Flux from a Periplaneta americana oocyte (Kunkel & Faszewski, 1995).

The outline of an American cockroach ovariole is given in yellow. The central follicle focused on in this preparation is the penultimate follicle in this ovariole. The blue lines depict the path of the proton ionprobe which was used to measure the proton flux vectors, which are shown in red. At the posterior end of this follicle the scanning reveals a cap of outward proton flux. This is the same area from which an outward potassium flux was measured. The correlation of the proton and potassium fluxes brings up several possibilities of mechanisms to explain the joint distribution. This pattern, detected earlier with the voltage probe, NVPpd, (Kunkel, 1986) was shown in a broad selection of Dictyopteran species to be correlated with the presumptive polarity of the future embryo (Kunkel, 1991). To view this 3-D data optimally, in 3-D stereo, one should obtain the data file 'bbfg95.kin' from the anonymous FTP download site and view it with the Mage utility which is downloadable from the Brookhaven National Laboratory FTP site.


If you have questions about the University of Massachusetts Vibrating Probe Facility, you can send an email message to its Director, Joe Kunkel.


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Page maintained by Joe Kunkel, joe@bio.umass.edu. Copyright(c) 1995. Created: 95/10/28 Updated: 97/02/14