20 research outputs found
Delayed Rectifier and A-Type Potassium Channels Associated with Kv 2.1 and Kv 4.3 Expression in Embryonic Rat Neural Progenitor Cells
BACKGROUND: Because of the importance of voltage-activated K(+) channels during embryonic development and in cell proliferation, we present here the first description of these channels in E15 rat embryonic neural progenitor cells derived from the subventricular zone (SVZ). Activation, inactivation, and single-channel conductance properties of recorded progenitor cells were compared with those obtained by others when these Kv gene products were expressed in oocytes. METHODOLOGY/PRINCIPAL FINDINGS: Neural progenitor cells derived from the subventricular zone of E15 embryonic rats were cultured under conditions that did not promote differentiation. Immunocytochemical and Western blot assays for nestin expression indicated that almost all of the cells available for recording expressed this intermediate filament protein, which is generally accepted as a marker for uncommitted embryonic neural progenitor cells. However, a very small numbers of the cells expressed GFAP, a marker for astrocytes, O4, a marker for immature oligodendrocytes, and betaIII-tubulin, a marker for neurons. Using immunocytochemistry and Western blots, we detected consistently the expression of Kv2.1, and 4.3. In whole-cell mode, we recorded two outward currents, a delayed rectifier and an A-type current. CONCLUSIONS/SIGNIFICANCE: We conclude that Kv2.1, and 4.3 are expressed in E15 SVZ neural progenitor cells, and we propose that they may be associated with the delayed-rectifier and the A-type currents, respectively, that we recorded. These results demonstrate the early expression of delayed rectifier and A-type K(+) currents and channels in embryonic neural progenitor cells prior to the differentiation of these cells
Differential changes in the end-plate architecture of functionally diverse muscles during aging
Desensitization and resensitization rates of glutamate-activated channels may regulate motoneuron excitability
Validating MODIS above-cloud aerosol optical depth retrieved from “color ratio” algorithm using direct measurements made by NASA's airborne AATS and 4STAR sensors
We present the validation analysis of above-cloud aerosol optical depth
(ACAOD) retrieved from the “color ratio” method applied to MODIS cloudy-sky
reflectance measurements using the limited direct measurements made by NASA's
airborne Ames Airborne Tracking Sunphotometer (AATS) and Spectrometer for
Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) sensors. A thorough search of the airborne database
collection revealed a total of five significant events in which an airborne
sun photometer, coincident with the MODIS overpass, observed partially
absorbing aerosols emitted from agricultural biomass burning, dust, and
wildfires over a low-level cloud deck during SAFARI-2000, ACE-ASIA 2001, and
SEAC4RS 2013 campaigns, respectively. The co-located satellite-airborne
matchups revealed a good agreement (root-mean-square difference < 0.1), with most
matchups falling within the estimated uncertainties associated the MODIS
retrievals (about −10 to +50 %). The co-retrieved cloud optical depth was
comparable to that of the MODIS operational cloud product for ACE-ASIA and
SEAC4RS, however, higher by 30–50 % for the SAFARI-2000 case study. The
reason for this discrepancy could be attributed to the distinct aerosol
optical properties encountered during respective campaigns. A brief
discussion on the sources of uncertainty in the satellite-based ACAOD
retrieval and co-location procedure is presented. Field experiments dedicated
to making direct measurements of aerosols above cloud are needed for the
extensive validation of satellite-based retrievals