Search results for " plant."

Immunological detection of tonoplast polypeptides in the plasma membrane of pea cotyledons

1996

The tonoplast is usually characterized by the presence of two electrogenic proton pumps: a vacuolartype H+-ATPase and a pyrophosphatase, as well as a putative water-channel-forming protein (γ-TIP). Using a post-embedding immunogold labelling technique, we have detected the presence of these transport-protein complexes not only in the tonoplast, but also in the plasma membrane and trans Golgi elements of maturing pea (Pisum sativum L.) cotyledons. These ultrastructural observations are supported by Western blotting with highly purified plasma-membrane fractions. In contrast to the vacuolar-type H+-ATPase, whose activity was not measurable, considerable pyrophosphatase activity was detected i…

2021

We report the assembly and annotation of the complete mitochondrial genome of the warningly-coloured wood tiger moth (Arctia plantaginis) and investigate its phylogenetic position within Arctiinae. The A.plantaginis mitogenome is 15,479 bp long with 13 protein-coding genes, 22 transfer RNAs, 2 ribosomal RNA genes, and an A + T-rich region (D-loop). The phylogenetic analyses based on 13 protein-coding genes showed A.plantaginis clustering within a clade of species with white wings and yellow or red bodies. This result can be useful in understanding the evolution of coloration in Arctiid moths.

Rac regulation of NtrbohD, the oxidase responsible for the oxidative burst in elicited tobacco cell

2003

Five cDNAs encoding Rac protein homologues to the Rho-related proteins from plants (Rop) were isolated in tobacco, and the function of one of them, Ntrac5, was studied. The Ntrac5 mRNA is repressed when tobacco leaves and cells are treated with the fungal elicitor cryptogein. Tobacco cells were transformed with sense constructs of Ntrac5 or Ntrac5V15, encoding the native GTP/GDP-bound form of this Rac protein homologue or the constitutively active mutant in its GTP-bound form, respectively. Immunological studies indicate that the corresponding protein is continuously located on the plasma membrane (PM). Both types of transformed cells show the same extra-cellular alkalinization as the contr…

S1/5 Photoaffinity labeling and photoaffinity cross-linking of ATP synthase complexes

2008

2014

The Vipp1 protein is essential in cyanobacteria and chloroplasts for the maintenance of photosynthetic function and thylakoid membrane architecture. To investigate its mode of action we generated strains of the cyanobacteria Synechocystis sp. PCC6803 and Synechococcus sp. PCC7942 in which Vipp1 was tagged with green fluorescent protein at the C-terminus and expressed from the native chromosomal locus. There was little perturbation of function. Live-cell fluorescence imaging shows dramatic relocalisation of Vipp1 under high light. Under low light, Vipp1 is predominantly dispersed in the cytoplasm with occasional concentrations at the outer periphery of the thylakoid membranes. High light ind…

Session 10 Photosynthesis

1994

How Realistically Does Outdoor UV-B Supplementation with Lamps Reflect Ozone Depletion: An Assessment of Enhancement Errors

2010

Limitations in the realism of currently available lamps mean that enhancement errors in outdoor experiments simulating UV-B radiation effects of stratospheric ozone depletion can be large. Here, we assess the magnitude of such errors at two Finnish locations, during May and June, under three cloud conditions. First we simulated solar radiation spectra for normal, compared with 10% and 20% ozone depletion, and convoluted the daily integrated solar spectra with eight biological spectral weighting functions (BSWFs) of relevance to effects of UV on plants. We also convoluted a measured spectrum from cellulose-acetate filtered UV-B lamps with the same eight BSWFs. From these intermediate results…

Effects of peroxidizing herbicides on protoporphyrin IX levels in non-chlorophyllous soybean cell culture

1990

Abstract The mode of action of 16 peroxidizing herbicides belonging to four different families (diphenyl ethers, oxadiazon, pyridine derivatives, and pyrazole derivatives) has been studied in nonchlorophyllous soybean cell cultures. Whenever possible, we have compared active and inactive compounds. Phytotoxic effects were estimated on the basis of growth inhibition, either in the dark or in the light. Protoporphyrin IX accumulations were estimated in dark-treated samples, using a simple methodology. In all cases, we have found a positive correlation between cellular damages and protoporphyrin IX accumulations. The results provide further evidences in favor of the light-dependent activity of…

Rigid Core and Flexible Terminus

2012

The structure of the major light-harvesting chlorophyll a/b complex (LHCII) was analyzed by pulsed EPR measurements and compared with the crystal structure. Site-specific spin labeling of the recombinant protein allowed the measurement of distance distributions over several intra- and intermolecular distances in monomeric and trimeric LHCII, yielding information on the protein structure and its local flexibility. A spin label rotamer library based on a molecular dynamics simulation was used to take the local mobility of spin labels into account. The core of LHCII in solution adopts a structure very similar or identical to the one seen in crystallized LHCII trimers with little motional freed…

Elicitation of tobacco cells with ergosterol activates a signal pathway including mobilization of internal calcium

2003

Abstract Ergosterol interacts with tobacco suspension ( Nicotiana tabacum ) cells and triggers pH changes of extracellular medium, oxidative burst and synthesis of phytoalexins. Compared with the responses induced by cryptogein, a proteinaceous elicitor from Phytophthora sp., oxidative burst and ΔpH changes were weaker whereas phytoalexin accumulation was higher with ergosterol. Cryptogein stimulated an apparent continuous uptake of external calcium within 40 min, whereas no net uptake of external calcium occurred upon the addition of ergosterol. However, the elicitation with both cryptogein and ergosterol resulted in an increase of the fluorescence of calcium green 1 in cytosol. The use of…