Search results for "Cell wall"
showing 10 items of 226 documents
Identification ofCandida albicanswall mannoproteins covalently linked by disulphide and/or alkali-sensitive bridges
2014
This paper describes the results obtained by analysing the human pathogen Candida albicans cell wall subproteome by mass spectrometry, using extraction procedures aimed at releasing proteins bound by disulphide bridges (RAE-CWP) or alkali-labile ester linkages (ALS-CWP). Ten of the total proteins released from the wall by β-ME and/or NaOH contained a potential signal peptide, lacked a GPI cell wall hydrophobic C-terminal domain and were identified as true wall proteins by in silico analysis, whereas four additional proteins were identified as bound to the plasma membrane. The results surprisingly demonstrated that, in addition to the expected RAE-CWP and ALS-CWP proteins, 16 GPI proteins we…
Common and form-specific cell wall antigens of Candida albicans as released by chemical and enzymatic treatments.
1996
In order to investigate the antigenic properties of the proteins and mannoproteins present in the cell surface of Candida albicans, and to identify individual antigenic moieties and their distribution, a number of polyclonal antisera were obtained by immunizing rabbits with chemical and enzymatic cell wall extracts obtained from intact cells from both growth forms (yeast and mycelium) of the fungus. Prior to injection, wall moieties present in the extracts were subjected to different treatments and/or purification procedures such as adsorption onto polystyrenelatex microbeads or electrophoretic separation. When used as probes in indirect immunofluorescence assays, the different antisera gav…
Analysis of the polypeptide composition of the cell walls of Neurospora crassa. Similarities with the proteinaceous material secreted by the slime va…
1991
The polypeptide composition of cell walls from the wild-type strain of Neurospora crassa is compared with that of the proteinaceous extracellular coat (PEM) secreted by the slime strain of this fungus. Analyses included determination of the polypeptide pattern by polyacrylamide gel electrophoresis and blotting followed by staining with Concanavalin A and antibodies raised against the overall antigenic components present in either (whole cell walls or PEM) structure. A complex protein assortment was found associated to the walls of the wild type strain. The similarities observed between the polypeptide patterns of the cell walls and PEM, in addition to the immunological cross-reactivity exhi…
Reversible stress softening and stress recovery of cellulose networks
2009
The mechanical properties of the plant cell wall play an important role in communication, differentiation and growth of plant cells. In particular, the expansive growth of plant cells is only possible because the material that forms the plant cell wall yields at a specific stress level, allowing for an increase in cell wall area. This process can be defined in mechanical terms as the relaxation of the wall stress. The current understanding of plant cell growth suggests that such relaxation behaviour occurs due to the presence of wall loosening agents rather than to the properties of the cellulose network itself. It is believed that certain nonenzymatic proteins, acting as wall loosening age…
Influence of Microspore Development on Pollen Protoplast Isolation in Digitalis obscura
1991
Summary Protocols for the enzymatic isolation of Digitalis obscura pollen protoplasts are described. The developmental stage of the microspores was a critical factor for successful isolation since protoplasts were obtained only from tetrads. The highest yield of viable protoplasts was achieved with an enzymatic mixture containing helicase, cellulase and pectolyase in 0.5 M sucrose. In different culture techniques employed, cell wall regeneration took place only when protoplasts were plated in agarose drops.
Effect of a novel chemical mixture on senescence processes and plant--fungus interaction in Solanaceae plants.
2001
The effects of exogenous application of a chemical mixture consisting of adipic acid monoethyl ester, furfurylamine, and 1,2,3,4-tetra-O-acetyl-beta-D-glucopyranose (FGA) on various metabolic pathways and the plant-fungus interaction have been studied in Solanaceae plants. Tomato and pepper plants were sprayed with the FGA mixture, and different biochemical parameters such as gas exchange, chlorophyll concentration, protein, cell wall sugar and phenolics contents, and peroxidase and phenylalanine ammonia lyase (PAL) activities were measured. FGA-treated plants showed, in general, an increase in cell wall sugar content and decreases in the chlorophyll degrading rate and the peroxidase activi…
Ultrastructural changes of sparkling wine lees during long-term aging in real enological conditions.
2012
Ultrastructural changes of lees of three series of sparkling wines produced using the traditional method during long-term aging (4 years) were assessed by high-pressure freezing in combination with transmission electron microscopy. The stratified structure of the cell wall disappeared throughout aging. After 18 months, the microfibrous material of the cell wall appeared more diffuse and the amorphous midzone of the inner wall layer was progressively degraded. From 30 months onward, the cell wall consisted of a tangled structure of fibers. In spite of these changes, the cell wall of yeasts remained unbroken at 48 months of wine aging. Cell membrane breakage was observed for the first time in…
Initial steps of wall protoplast regeneration in Candida albicans
1997
Summary Cell wall regeneration of individual Candida albicans yeast and mycelial protoplasts was studied with confocal and electron microscopy using polyclonal antibodies and leetins. Quantitative measurements of the fluorescence emitted by individual protoplasts during the process of regeneration indicate that chitin is the first polymer to be laid down, whereas β(1,3)- and β(1,6)glucan are incorporated at a later stage. Mannoproteins were found on the surface of fresh protoplasts and those newly synthesized were then deposited with time. During the first steps of wall regeneration, the proteins that interacted covalently with chitin or glucan were different, but the same species were foun…
Nuclear factors binding to the extensin promoter exhibit differential activity in carrot protoplasts and cells
1992
The expression of the cell wall protein extensin, a hydroxyproline-rich glycoprotein, is induced by several different stimuli, including wounding. The process of protoplast preparation mimics the wounding effect and results in the induction of extensin. Using transient expression in protoplasts we analyzed several deletions of the extensin promoter. We identified an important transcriptional regulatory element located between the two TATA boxes that characterize the extensin promoter. Other regulatory elements, located further upstream between -719 to -658, are necessary for maximum level of expression. Employing electrophoretic mobility shift assays and methylation interference experiments…
Differences in the cell walls and extracellular polymers of the two Trebouxia microalgae coexisting in the lichen Ramalina farinacea are consistent w…
2015
Trebouxia TR1 and T. TR9 are the two microalgae that coexist within Ramalina farinacea thalli. In the presence of Pb, TR9 formed extracellular aggregates, while TR1 showed a lower wall lead retention capability. Herein, we studied the cell walls and extracellular polymers (EPS) of TR1 and TR9, and their possible implication in the different Pb retention capacity of these microalgae. The proportion of cell walls on the overall cell biomass was 2.6 times higher in TR9 than in TR1. Glycosyl linkage analysis indicated the presence of hot-water soluble β-galactofuranan(s) in both cell walls, distinct from that previously described in Asterochloris, with increased rhamnose content in TR9 and a hi…