Search results for "Plant cell"

Microtubule distribution in gravitropic protonemata of the mossCeratodon

1990

Tip cells of dark-grown protonemata of the moss Ceratodon purpureus are negatively gravitropic (grow upward). They possess a unique longitudinal zonation: (1) a tip group of amylochloroplasts in the apical dome, (2) a plastid-free zone, (3) a zone of significant plastid sedimentation, and (4) a zone of mostly non-sedimenting plastids. Immunofluorescence of vertical cells showed microtubules distributed throughout the cytoplasm in a mostly axial orientation extending through all zones. Optical sectioning revealed a close spatial association between microtubules and plastids. A majority (two thirds) of protonemata gravistimulated for > 20 min had a higher density of microtubules near the lowe…

Uptake of endocytic markers by rice cells: variations related to the growth phase.

2001

Endocytosis is now considered a basic cellular process common to plant cells. Although both non-specific and receptor-mediated endocytosis appear to take place in plant cells, the physiological role of the latter remains unclear. We have investigated the endocytic process in rice cell suspensions using two biotinylated proteins, peroxidase and bovine serum albumin (bHRP and bBSA), as markers. First, we show that markers are internalized by rice cells and appear in intracellular membranes. The uptake of the two markers is temperature dependent, saturable with time and markers dose and it is competed by free biotin. Thus, it shows the properties of a receptor-mediated process. We also show th…

Cryptogein-Induced Anion Effluxes

2014

Anion effluxes are amongst the earliest reactions of plant cells to elicitors of defence responses. However, their properties and their role in disease resistance remain almost unknown. We previously demonstrated that cryptogein, an elicitor of tobacco defence responses, induces a nitrate (NO(3) (-)) efflux. This efflux is an early prerequisite to the cryptogein-triggered hypersensitive response (HR). Here, we analyzed the electrophysiological properties of the elicitor-mediated NO(3) (-) efflux and clarified the mechanisms through which it contributes to cell death. Application of the discontinuous single electrode voltage-clamp technique in tobacco cells elicited with cryptogein enabled u…

Characterization of Cop I Coat Proteins in Plant Cells

2000

Membrane traffic in eukaryotic cells is mediated by COP (coat protein)-coated vesicles. Their existence in plant cells has not yet been unequivocally demonstrated, although coated vesicles (probably with a COP coat) can be seen by electron microscopy. At the gene level, plant cells seem to contain all the components necessary to form COP-coated vesicles. In this paper, we have used antibodies raised against mammalian COPI coat proteins to detect putative homologues in rice (Oryza sativa) cells. Using these antibodies, we have found that rice cells contain alpha-, beta-, beta'-, and gamma-COP, as well as ADP-ribosylation factor (ARF) 1 protein. In addition, we show that antibodies against ma…

Glucosylation of isatin-3-oxime followed by 2D in situ NMR in plant cells at highest magnetic field without labelling.

2001

The glucosylation of isatin-3-oxime (1) was monitored by in situ 2D 1H-13C inverse correlated gradient assisted NMR spectroscopy in plant cell suspension cultures of Rauvolfia serpentina without labelling. The applied high magnetic field of 800 MHz allowed measurements within 20 min at concentrations of 1 of 5.76 mM. Complete glucosylation of 1 occurs inside the cells within 72 hours. During this time isatin-3-oxime-glucoside (2) accumulates without further metabolism.

In-Situ atomic force microscopic observation of ion beam bombarded plant cell envelopes

2007

Abstract A program in ion beam bioengineering has been established at Chiang Mai University (CMU), Thailand, and ion beam induced transfer of plasmid DNA molecules into bacterial cells (Escherichia coli) has been demonstrated. However, a good understanding of the fundamental physical processes involved is lacking. In parallel work, onion skin cells have been bombarded with Ar+ ions at energy 25 keV and fluence1–2 × 1015 ions/cm2, revealing the formation of microcrater-like structures on the cell wall that could serve as channels for the transfer of large macromolecules into the cell interior. An in-situ atomic force microscope (AFM) system has been designed and installed in the CMU bio-impl…

Influence of SiO2 nanoparticles on relative fluorescence of plant cells

2015

Nanoparticles (nano-scale particles (NSPs)) are defined as particles with dimensions less than 100 nm. SiO<sub>2</sub> nanoparticles are one of the most widely common nanoparticles in the environment, particularly in urban areas. The sources of SiO<sub>2 </sub>nanoparticles are very different, including natural nanoparticles, anthropogenic and engineered nanoparticles. The SiO<sub>2 </sub>nanoparticles could be considered a source of different pollution effects on leaving organisms. Nevertheless, knowledge of the mechanisms, through which the SiO<sub>2 </sub>nanoparticles affect cells, is incomplete. The aim of the research was to elaborate a …

Aminopropyltransferases involved in polyamine biosynthesis localize preferentially in the nucleus of plant cells

2012

Plant aminopropyltransferases consist of a group of enzymes that transfer aminopropyl groups derived from decarboxylated S-adenosyl-methionine (dcAdoMet or dcSAM) to propylamine acceptors to produce polyamines, ubiquitous metabolites with positive charge at physiological pH. Spermidine synthase (SPDS) uses putrescine as amino acceptor to form spermidine, whereas spermine synthase (SPMS) and thermospermine synthase (TSPMS) use spermidine as acceptor to synthesize the isomers spermine and thermospermine respectively. In previous work it was shown that both SPDS1 and SPDS2 can physically interact with SPMS although no data concerning the subcellular localization was reported. Here we study the…

In vivo NMR at 800 MHz to monitor alkaloid metabolism in plant cell cultures without tracer labeling.

2001

Dynamics of the biosynthesis of methylursubin in plant cells employing in vivo 13CNMR without labelling.

1995

Abstract In vivo NMR experiments with a digital 600 MHz instrument, exploiting the natural abundance of 13C, allowed us for the first time to follow the biosynthesis of the newly detected glycoside, methylursubin ( 4- methoxyphenyl -O-β- d -primeveroside ), from 4-methoxyphenol through the intermediate methylarbutin in cell suspensions of the Indian medical plant, Rauwolfia serpentina. The metabolic dynamics indicate that, within 48 hr, 4-methoxyphenol is almost completely converted into the primeveroside, methylursubin. Because of the higher sensitivity at 150.9 MHz compared to that at 100.6 MHz, measuring times could be reduced to 1.5 hr. This allows detailed monitoring of the conversion …