Search results for "Protoplast"
showing 10 items of 55 documents
An integrated proteomic and metabolomic study to evaluate the effect of nucleus-cytoplasm interaction in a diploid citrus cybrid between sweet orange…
2018
Key message: Our results provide a comprehensive overview how the alloplasmic condition might lead to a significant improvement in citrus plant breeding, developing varieties more adaptable to a wide range of conditions. Abstract: Citrus cybrids resulting from somatic hybridization hold great potential in plant improvement. They represent effective products resulting from the transfer of organelle-encoded traits into cultivated varieties. In these cases, the plant coordinated array of physiological, biochemical, and molecular functions remains the result of integration among different signals, which derive from the compartmentalized genomes of nucleus, plastids and mitochondria. To dissect …
Citrus rootstock breeding: response of four allotetraploid somatic hybrids to Citrus tristeza virus induced infections
2018
Four allotetraploid somatic hybrids of citrus, with potential for rootstock improvement, have been evaluated for their response to Citrus tristeza virus (CTV) infection. CTV is the most important viral pathogen affecting citrus production worldwide. Somatic combinations of ‘Milam’ lemon (Citrus jambhiri Lush.) + Sour orange (C. aurantium L Osb.), Calamondin (C. madurensis Lour.) + ‘Keen’ sour orange (C. aurantium L.), Calamondin + ‘Femminello‘ lemon (C. limon L. Burm. F.) and Cleopatra mandarin (C. reshni Hort. ex Tan.) + ‘Femminello’ lemon, were studied. Plants were grafted with CTV-infected “Valencia” sweet orange budwood. Two different CTV strains collected in Sicily, considered as “mild…
In vivoanalysis of the lumenal binding protein (BiP) reveals multiple functions of its ATPase domain
2007
International audience; The endoplasmic reticulum (ER) chaperone binding protein (BiP) binds exposed hydrophobic regions of misfolded proteins. Cycles of ATP hydrolysis and nucleotide exchange on the ATPase domain were shown to regulate the function of the ligand-binding domain in vitro. Here we show that ATPase mutants of BiP with defective ATP-hydrolysis (T46G) or ATP-binding (G235D) caused permanent association with a model ligand, but also interfered with the production of secretory, but not cytosolic, proteins in vivo. Furthermore, the negative effect of BiP(T46G) on secretory protein synthesis was rescued by increased levels of wild-type BiP, whereas the G235D mutation was dominant. U…
Formation of a new cell wall by protoplasts of Candida albicans: effect of papulacandin B, tunicamycin and Nikkomycin.
1987
SUMMARY: Incorporation of polysaccharides into the walls of regenerating protoplasts of Candida albicans was followed in the presence of papulacandin B, tunicamycin and nikkomycin. With the first drug, chitin was incorporated normally whereas incorporation of glucans and mannoproteins was significantly decreased. Tunicamycin decreased incorporation of all wall polymers when added at the beginning of the regeneration process but blocked only mannan and alkali-insoluble glucan incorporation when added after 5 h. Nikkomycin inhibited chitin synthesis, and the walls formed by the protoplasts were enriched in alkali-soluble glucan. Pulse-chase experiments suggested that a precursor-product relat…
Incorporation of mannoproteins into the walls of aculeacin A-treated yeast cells
1986
Inhibition of the synthesis of alkali-insoluble glucan by aculeacin A in Saccharomyces cerevisiae cells caused a decrease in the incorporation of a high molecular weight heterogeneous mannoprotein material and of a 33,000 mannoprotein into the wall network. This was concomitant with the excretion of the latter molecule into the growth medium. Regenerating yeast protoplasts liberated considerable amounts of the heterogeneous material to the medium independently of the presence of aculeacin. The protoplast walls did lack this component and contained only minor amounts of the 33,000 molecule, which was also completely absent from walls of aculeacin-treated protoplasts. Considerable levels of t…
Pga13 in Candida albicans is localized in the cell wall and influences cell surface properties, morphogenesis and virulence.
2011
The fungal cell wall is an essential organelle required for maintaining cell integrity and also plays an important role in the primary interactions between pathogenic fungi and their hosts. PGA13 encodes a GPI protein in the human pathogen Candida albicans, which is highly up-regulated during cell wall regeneration in protoplasts. The Pga13 protein contains a unique tandem repeat, which is present five times and is characterized by conserved spacing between the four cysteine residues. Furthermore, the mature protein contains 38% serine and threonine residues, and therefore probably is a highly glycosylated cell wall protein. Consistent with this, a chimeric Pga13-V5 protein could be localiz…
A kinetic study on the regeneration ofCandida albicansprotoplasts in the presence of cell wall synthesis inhibitors
1993
Aculeacin A and papulacandin B block cell wall regeneration in Candida albicans protoplasts at an intermediate step in which the protoplasts have not yet synthesized the rigid structure of the cell wall and are therefore still osmotically sensitive. In the presence of the antibiotics, total synthesis of glucan is not significantly lowered with respect to control cells, although most of it appears either in the culture medium or in the regenerating wall as alkali-soluble glucan. Thus, it is proposed that echinocandins (such as aculeacin A) and papulacandins may not inhibit glucan synthesis per se but instead inhibit its incorporation into the supramolecular organization of the cell wall.
Incorporation of specific wall proteins during yeast and mycelial protoplast regeneration in Candida albicans
1994
The kinectics of incorporation of two precursor mannoproteins into the regenerating cell wall of Candida albicans protoplasts have been followed at 28°C and 37°C using two monoclonal antibodies specific for protein epitopes (MAb 1B12 and 4C12) as probes. Both molecules were secreted from the beginning of the regeneration process, and their incorporation was retarded significantly. Analysis of the secreted materials by Western immunoblotting with MAb 1B12 allowed the identification of two closely migrating bands at apparent Mr higher than 170 kDa and significant amounts of a highly polydisperse material of even greater molecular mass. Some of these mannoproteinaceous species carried both N- …
Wall formation by Candida albicans yeast cells: synthesis, secretion and incorporation of two types of mannoproteins.
1993
SUMMARY: The mannoprotein components solubilized from the walls of Candida albicans blastoconidia following degradation of the glucan network with β-glucanase (Zymolyase) have higher molecular masses than their probable precursors present in the supernatant of regenerating protoplasts. It therefore appears that the mannoproteins are released from the walls as part of supramolecular complexes. Immunological analysis using both polyclonal and monoclonal antibodies has demonstrated the probable relationship between molecules found in a mixed membrane preparation, those secreted by regenerating protoplasts, and those present in yeast cell walls. Some mannoproteins secreted by protoplasts incuba…
Involvement of transglutaminase in the formation of covalent cross-links in the cell wall of Candida albicans.
1995
Activity of the enzyme glutaminyl-peptide--glutamylyl-transferase (EC 2.3.2.13; transglutaminase), which forms the interpeptidic cross-link N epsilon-(gamma-glutamic)-lysine, was demonstrated in cell-free extracts obtained from both the yeast like and mycelial forms of Candida albicans. Higher levels of enzymatic activity were observed in the cell wall fraction, whereas the cytosol contained only trace amounts of activity. Cystamine, a highly specific inhibitor of the enzyme, was used to analyze a possible role of transglutaminase in the organization of the cell wall structure of the fungus. Cystamine delayed protoplast regeneration and inhibited the yeast-to-mycelium transition and the inc…