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111.
The effects of abscisic acid (ABA) treatments on the surfaceelectrical properties of cells and isolated protoplasts fromCatharanthus roseus cell suspension cultures were studied byelectrophoretic mobility and 9-aminoacridine (9AA) fluorescencemeasurements. The surface charge densities of the cells andprotoplasts estimated from electrokinetic data were 0.064Cm2and 0.048 C m2 respectively. These values wereclose to that estimated by 9AA fluorescence technique i.e.,0.053 Cm2 for the cells and 0.041 Cm2for the isolated protoplasts accordingly. The net negative surfacecharge density decreased after application of 10 µM and50 µM ABA in both cells and protoplats, the more pronouncedeffect being observed at 10 µM ABA. When 100 µMABA was supplemented to the cell suspension culture the oppositeeffect was observed. The average charge density increased to0.074 C m2 for the cells, and to 0.055C m2 for protoplasts, as revealed from the 9AA measurements.The results are discussed in terms of specific concentrationdependent ABA-induced alterations of the electrostatic propertiesof cell and protoplast membranes. (Received December 12, 1994; Accepted April 3, 1995) 相似文献
112.
Enhancement of the light-triggered electrical response in plant cells following their de-energization with uncouplers 总被引:1,自引:0,他引:1
Light-triggered membrane potential changes in cells of a liverwort Anthoceros are greatly enhanced by the ionophorous uncouplers nigericin and monesin. Stimulation of the light-triggered electrical response (LTER) by nigericin occurred concomitantly with inhibition of a slow decline in the chlorophyll fluorescence, which suggests that the transmembrane pH gradient in thylakoids is not essential for generation of LTER at the plasma membrane. The extent of monensin-stimulated LTER remained high under a diminished driving force for the ionophore-induced proton-cation exchange across the plasma membrane (elevation of the external Na+ concentration from 1 to 50 m M ), which indicates that energy uncoupling in chloroplasts is more related to the electric response enhancement than the induction of the H+ /K+ (Na+ ) exchange at the plasma membrane. Enhancement of LTER by ionophores occurs in parallel with stimulation of light-triggered pH changes (alkalinization) in the vicinity of the cell surface, which suggests an association of trans-membrane H+ fluxes with LTER. The results are consistent with the hypothesis that illumination produces a temporary inhibition of the plasma membrane H+ pump with a subsequent activation of gated channels and transient rapid depolarization of the cell. 相似文献
113.
Each cryptomonad strain contains only a single spectroscopic type of biliprotein. These biliproteins are isolated as 50000 kDa '2 complexes which carry one bilin on the and three on the subunit. Six different bilins are present on the cryptomonad biliproteins, two of which (phycocyanobilin and phycoerythrobilin) also occur in cyanobacterial and rhodophytan biliproteins, while four are known only in the cryptomonads. The subunit is encoded on the chloroplast genome, whereas the subunits are encoded by a small nuclear multigene family. The subunits of all cryptomonad biliproteins, regardless of spectroscopic type, have highly conserved amino acid sequences, which show > 80% identity with those of rhodophytan phycoerythrin subunits. In contrast, cyanobacteria and red algal chloroplasts each contain several spectroscopically distinct biliproteins organized into macromolecular complexes (phycobilisomes). The data on biliproteins, as well as several other lines of evidence, indicate that the cryptomonad biliprotein antenna system is primitive and antedates that of the cyanobacteria. It is proposed that the gene encoding the cryptomonad biliprotein subunit is the ancestral gene of the gene family encoding cyanobacterial and rhodophytan biliprotein and subunits.Abbreviations Chl
chlorophyll
- CER
chloroplast endoplasmic reticulum
- SSU rRNA
small subunit ribosomal RNA 相似文献
114.
115.
Alexander A. Bachmanov Danielle R. Reed Yuro Ninomiya Masashi Inoue Michael G. Tordoff R. Arlen Price Gary K. Beauchamp 《Mammalian genome》1997,8(8):545-548
Individual variability in sucrose consumption is prominent in humans and other species. To investigate the genetic contribution
to this complex behavior, we conducted behavioral, electrophysiological, and genetic studies, using male progeny of two inbred
mouse strains (C57BL/6ByJ [B6] and 129/J [129]) and their F2 hybrids. Two loci on Chromosome (Chr) 4 were responsible for over 50% of the genetic variability in sucrose intake. These
loci apparently modulated intake by altering peripheral neural responses to sucrose. One locus affected the response threshold,
whereas the other affected the response magnitude. These findings suggest that the majority of difference in sucrose intake
between male B6 and 129 mice is due to polymorphisms of two genes that influence receptor or peripheral nervous system activity.
Received: 27 January 1997 / Accepted: 17 March 1997 相似文献
116.
117.
Expression of connexin43 mRNA in adult rodent brain 总被引:3,自引:0,他引:3
E. Simbürger Alexander Stang Marian Kremer R. Dermietzel 《Histochemistry and cell biology》1997,107(2):127-137
118.
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120.
Alexander Steinkasserer Tania Jones Denise Sheer Karl Koettnitz Joachim Hauber Dorian Bevec 《Genomics》1995,25(3)
The eukaryotic initiation factor 5A (eIF-5A) has been identified as an essential cofactor for the HIV-1 trans-activator protein Rev. Rev plays a key role in the complex regulation of HIV-1 gene expression and thereby in the generation of infectious virus particles. Expression of eIF-5A is vital for Rev function, and inhibition of this interaction leads to a block of the viral replication cycle. In humans, four different eIF-5A genes have been identified. One codes for the eIF-5A protein and the other three are pseudogenes. Using a panel of somatic rodent—human cell hybrids in combination with fluorescence in situ hybridization analysis, we show that the four genes map to threedifferent chromosomes. The coding eIF-5A gene (EIF5A) maps to 17p12–p13, and the three pseudogenes EIF5AP1, EIF5AP2, and EIF5AP3 map to 10q23.3, 17q25, and 19q13.2, respectively. This is the first localization report for a eukaryotic cofactor for a regulatory HIV-1 protein. 相似文献