Search results for "Protoplast"
showing 10 items of 55 documents
Transformation of Aspergillus parasiticus using autonomously replicating plasmids from Aspergillus nidulans.
1994
A genetic transformation system for the aflatoxin-producing fungus Aspergillus parasiticus using two autonomously replicating plasmids from A. nidulans (ARp1 and pDHG25) is reported. Transformation frequencies using the plasmid pDHG25 were from 5 x 10(2) to 2.5 x 10(4) transformants per 10(6) viable protoplasts and microgram DNA. The stability of the plasmids in the transformants was also studied. This transformation system offers a new opportunity to clone genes related to aflatoxin production using appropriate aflatoxin-defective mutants.
Gibberellic acid stimulates lipid metabolism in barley aleurone protoplasts
1991
Abstract Changes in the lipid composition of barley aleurone protoplasts following incubation in the presence or absence of gibberellic acid (GA) were studied and correlated with cell development. Analysis of neutral lipids in protoplast extracts and purified lipid bodies provide evidence for the strong effect of GA on the mobilization of storage lipids. In vivo protoplast staining with the membrane marker N -phenyl-l-naphthylamine (NPN) and phospholipid determinations of protoplast extracts show an increase in membrane lipids during protoplast incubation. GA stimulates phospholipid metabolism by increasing the synthesis of phosphatidyl ethanolamine and phosphatidyl choline, the major phosp…
Trafficking of the human transferrin receptor in plant cells: effects of tyrphostin A23 and brefeldin A.
2006
Plant cells possess much of the molecular machinery necessary for receptor-mediated endocytosis (RME), but this process still awaits detailed characterization. In order to identify a reliable and well-characterized marker to investigate RME in plant cells, we have expressed the human transferrin receptor (hTfR) in Arabidopsis protoplasts. We have found that hTfR is mainly found in endosomal (Ara7- and FM4-64-positive) compartments, but also at the plasma membrane, where it mediates binding and internalization of its natural ligand transferrin (Tfn). Cell surface expression of hTfR increases upon treatment with tyrphostin A23, which inhibits the interaction between the YTRF endocytosis signa…
Effect of ethanol on membrane fluidity of protoplasts fromSaccharomyces cerevisiae andKloeckera apiculata grown with or without ethanol, measured by …
1994
Direct measurements of membrane fluidity by fluorescence anisotropy of protoplasts fromKloeckera apiculata andSaccharomyces cerevisiae, a low and a high ethanol tolerant strain respectively, are presented. The comparison of the behaviour of the two strains grown with or without ethanol enabled us to demonstrate the existing relationship between ethanol tolerance and membrane fluidity.
Changes in the cell wall glycoprotein composition of Candida albicans associated to the inhibition of germ tube formation by EDTA.
1994
Hyphal development in Candida albicans was blocked by EDTA. This effect was not due to a general growth inhibition since the chelator did not affect protein and DNA synthesis. Recovery of mycelial growth was observed when EDTA-grown cells were incubated at 37 degrees C in EDTA-free medium. High-molecular-weight mannoproteins (HMWM) that are mycelium-specific wall components, and particularly a 260-kDa species (HMWM-260), were absent in the wall of cells grown under germination conditions in the presence of EDTA. Synthesis of the HMWM-260 species was not inhibited but its incorporation (secretion) into the wall structure seemed to be blocked in EDTA-treated cells.
Genomic response programs of Saccharomyces cerevisiae following protoplasting and regeneration.
2007
Abstract Global transcription profiling during regeneration of Saccharomyces cerevisiae protoplasts was explored. DNA microarrays measured the expression of 6388 genes and wall removal resulted initially in over-expression of 861 genes that decayed later on, a behaviour expected from a transient stress response. Kinetics of expression divided the genes into 25 clusters. Transcription of the genes from clusters 14–25 was initially up-regulated, suggesting that the grouped genes permitted cell adaptation to the removal of the wall. Clustering of genes involved in “wall structure and biosynthesis” showed that most of them had initially low levels of expression that increased along the process.…
Evaluation of different genetic procedures for the generation of artificial hybrids in Saccharomyces genus for winemaking
2012
Several methods based on recombinant DNA techniques have been proposed for yeast strain improvement; however, the most relevant oenological traits depend on a multitude of loci, making these techniques difficult to apply. In this way, hybridization techniques involving two complete genomes became interesting. Natural hybrid strains between different Saccharomyces species have been detected in diverse fermented beverages including wine, cider and beer. These hybrids seem to be better adapted to fluctuating situations typically observed in fermentations due to the acquisition of particular physiological properties of both parental strains. In this work we evaluated the usefulness of three dif…
A comparative study of the incorporation of a 1,6-beta-glucan and an O-glycosylated protein epitope into the cell wall of Candida albicans.
1996
The topological distribution of two epitopes in the cell wall of Candida albicans, the kinetics of their incorporation into the regenerating protoplast wall, and the effect of different antibiotics upon their incorporation and localization have been studied. To do so, two monoclonal antibodies that react against an O-glycosylated mannoprotein (1B12) and against a 1,6-beta-glucan epitope (JRR1) were used. The results show that the JRR1 epitope is localized in an internal layer of the cell wall, in contrast to the 1B12 epitope, which is superficial, and that the incorporation of the JRR1 epitope into walls of regenerating protoplasts precedes that of the 1B12 epitope. The JRR1 epitope is norm…
Rice protoplasts isolated directly from mature-embryo-derived calli
1996
Mature-embryo-derived calli of japonica rice (Oryza sativa L) Taipei 309 were used for replicated protoplast isolation experiments. Six out of nine callus lines produced protoplasts with satisfactory yield of 5.20×106–8.96×106 protoplasts/g FW (fresh weight). The remaining three callus lines initiated from seeds of cryopreserved-callus-derived plants had rooty calli, resulting in low yield of protoplasts and a large number of isolated banana-shape intact cells. Viability of protoplasts ranged 87.46%–94.15%. The average size of protoplasts was 207.49–379.04 μm2 in different callus lines. Comparitive experiments were also carried out using both calli and suspension culture cells for protoplas…
Polypeptide composition of invertase-containing vesicles of Saccharomyces cerevisiae
1990
Vesicles containing invertase activity were obtained from protoplast homogenates of Saccharomyces cerevisiae by differential centrifugation followed by gel chromatography. These vesicles were similar in size and shape to yeast coated vesicles, and appear to have a complex polypeptide composition. Most of these polypeptides were seemingly bound to the surface of the vesicular structures, being released by treatment with alkali. A protein with an electrophoretic mobility similar to that of yeast clathrin (molecular mass of 185 kDa) co-purified with vesicles containing invertase activity, and exhibited cross-reactivity with anti-mammalian (pig) clathrin antibodies.