Search results for "Protoplast"
showing 10 items of 55 documents
Mutational analysis of the RNA-binding domain of the Prunus necrotic ringspot virus (PNRSV) movement protein reveals its requirement for cell-to-cell…
2005
AbstractThe movement protein (MP) of Prunus necrotic ringspot virus (PNRSV) is required for cell-to-cell movement. MP subcellular localization studies using a GFP fusion protein revealed highly punctate structures between neighboring cells, believed to represent plasmodesmata. Deletion of the RNA-binding domain (RBD) of PNRSV MP abolishes the cell-to-cell movement. A mutational analysis on this RBD was performed in order to identify in vivo the features that govern viral transport. Loss of positive charges prevented the cell-to-cell movement even though all mutants showed a similar accumulation level in protoplasts to those observed with the wild-type (wt) MP. Synthetic peptides representin…
Phenotypic characterization of the progenies of rice plants derived from cryopreserved calli
1999
The progenies of rice plants (Oryza sativa L.) differentiated from calli that had been cryopreserved and from control (non-cryopreserved) calli were used to study the influence of selection pressure during cryopreservation. The phenotypic evaluation of these progenies was based mainly on the response of seedlings and calli to freezing stress and on the characterization of protoplast and cell populations by flow cytometric analyses. The patterns of response to freezing stress, as well as the variations in some morphological and physiological cell parameters, were unrelated to the origin (cryopreserved or control calli) of the parental plants.
Vesicle formation in the membrane of onion cells (Allium cepa) during rapid osmotic dehydration
2009
BACKGROUND AND AIMS Optimization of osmotic dehydration in different plant cells has been investigated through the variation of parameters such as the nature of the sugar used, the concentration of osmotic solutions and the processing time. In micro-organisms such as the yeast, Saccharomyces cerevisiae, the exposure of a cell to a slow increase in osmotic pressure preserves cell viability after rehydration, while sudden dehydration involves a lower rate of cell viability, which could be due to membrane vesiculation. The aim of this work is to study cytoplasmic vesicle formation in onion epidermal cells (Allium cepa) as a function of the kinetics of osmotic pressure variation in the external…
Purification of a cytochrome aa3 terminal oxidase from protoplast membrane vesicles of Micrococcus luteus
1994
Abstract A cytochrome aa 3 terminal oxidase was isolated from protoplast membrane vesicles of Micrococcus luteus grown under aerobic conditions. The purified complex showed similarities to cytochrome c oxidase (EC 1.9.3.1) of the electron transport chain of mitochondria and many prokaryotes. The enzyme was solubilized by subsequent treatment with the detergents CHAPS and n- dodecyl -β- d - maltoside and purified by ion-exchange chromatography using poly- l -lysine agarose and TMAE-fractogel-650 (S) columns, followed by hydroxyapatite chromatography. The purified complex is composed of two major subunits with apparent molecular masses of 54 and 32 kDa. After purification the isolated enzyme …
Improved Mesophyll Protoplast Culture and Plant Regeneration in Arabidopsis thaliana (L.) Heynh., Genotype Landsberg Erecta
1993
Summary The response of in vitro cultured Arabidopsis thaliana mesophyll protoplasts was investigated with the aim of characterising the crucial factors that affect plating efficiencies and plant regeneration. We selected the genotype Landsberg erecta, which is frequently used for genetic studies, but which is known to respond poorly in protoplast culture. Factors permitting vigorous vegetative growth of the donor plants, i.e. short light period and avoidance of high temperature, were found to be advantageous. Selection of competent leaves and fractionation of protoplast populations indicated that predominantly protoplasts derived from still expanding, yet not highly immature mesophyll cell…
The First Cell Division Cycle in Nicotiana Mesophyll Protoplasts Cultured in Vitro. I. Methods to Determine Cycle Kinetics
1991
Summary The progress of freshly isolated and in vitro cultured mesophyll protoplasts through the first mitotic cycle was studied with the aim of determining the frequency and timing of the G2-phase. Putative G1 and G2 phase cells were identified by measuring the relative DNA content through improved cytofluorimetry of DAPI-stained nuclei. S-phase nuclei were identified by labelling with the thymidine-analogue BrdU, which was subsequently immuno-localized with a BrdU-specific monoclonal antibody. The cells entered S-phase after 12–24h and a maximum of G2 cells was observed 24–36h after culture initiation. Most of the cells had divided after 48 to 72 h.
Isolation, culture and plant regeneration from protoplasts of Sideritis angustifolia
1998
Summary Factors promoting high yields of viable protoplasts from leaves of Sideritis angustifolia are reported. Isolated protoplasts divided and gave rise to callus when plated in modified liquid MS medium with growth regulators. Best plating efficiency was obtained when protoplast were cultured in the presence of 6 μM BA and 2 μM NAA. Calli were then transferred onto solidified regeneration media. Adventitious bud differentiation was only observed in calli grown on medium containing 8 μM BA and 2 μM NAA. These buds proliferated quickly when placed on hormone-free medium and subsequendy regenerated new buds and shoots. Once developed shoots were excised, the remaining tissues maintained thi…
Secretory Pathway Research: The More Experimental Systems the Better
2012
Transient gene expression, in plant protoplasts or specific plant tissues, is a key technique in plant molecular cell biology, aimed at exploring gene products and their modifications to examine functional subdomains, their interactions with other biomolecules, and their subcellular localization. Here, we highlight some of the major advantages and potential pitfalls of the most commonly used transient gene expression models and illustrate how ectopic expression and the use of dominant mutants can provide insights into protein function.
BIOTECHNOLOGICAL APPROACHES TO THE GENETIC IMPROVEMENT OF CHRYSANTHEMUM CINERARIAEFOLIUM L.
2011
The interest in sustainable agriculture has increased the demand of plant-derived compounds which can be less toxic both to mammals and to the environment than the synthetic agrochemicals. Chrysanthemum cinerariaefolium L. (Asteraceae), commonly termed pyrethrum, is an economically important crop from highlands of tropical and subtropical regions of the world. It is grown for the extraction of pyrethrins, natural insect repellents of plant origin. Pyrethrins are a mixture of six compounds produced by esterification of two acids (chrysanthemic and pyrethric acid) with three mono-terpene-alcohols (pyrethrolone-5, jasmolone-3 and cinerolone-4). The principale source of pyrethrins are the dried…
Genomic response programs of Candida albicans following protoplasting and regeneration
2005
Transcription profiling of Candida albicans cells responding to the elimination of the wall (protoplasts) and posterior regeneration was explored. DNA microarrays were used to measure changes in the expression of 6039 genes, and the upregulated genes during regeneration at 28 degrees C were assigned to fourteen categories. A total of 407 genes were upregulated during the process, of which 144 reached a maximum after 1 h. MKC1, a gene encoding a member of the regulatory pathway involved in cell wall integrity was overexpressed. Time-dependent expression divided the genes into 40 clusters. Clusters 1-19 were highly expressed initially (time 0) and downregulated following incubation, whereas t…