Search results for "WALL"
showing 10 items of 970 documents
Secretion, interaction and assembly of two O-glycosylated cell wall antigens from Candida albicans.
2001
The mechanisms of incorporation of two antigens have been determined using a monoclonal antibody (3A10) raised against the material released from the mycelial cell wall by zymolyase digestion and retained on a concanavalin A column. One of the hybridomas secreted an IgG that reacted with two bands in Western blots. Indirect immunofluorescence showed that the antigens were located on the surfaces of mycelial cells, but within the cell walls of yeasts. These antigens were detected in a membrane preparation, in the SDS-soluble material and in the material released by a 1,3-beta-glucanase and chitinase from the cell walls of yeast and mycelial cells. In the latter three samples, an additional h…
Cell wall protein and glycoprotein constituents of Aspergillus fumigatus that bind to polystyrene may be responsible for the cell surface hydrophobic…
1996
Cell surface hydrophobicity (CSH) of Aspergillus fumigatus grown both in complex medium (yeast extract/peptone/dextrose; YPD) and minimal (Vogel's N) medium was monitored by assessing attachment of polystyrene microspheres to the cell surface. It was found that mature mycelium was hydrophobic. Treatment of intact mycelium with beta-mercaptoethanol (beta ME) abolished binding of the microspheres to hyphal elements, and coating of the microspheres with beta ME extracts from mycelium inhibited their attachment to intact mycelial cells. A. fumigatus mycelium was tagged in vivo with biotin and treated with beta ME. The beta ME extracts were analysed by SDS-PAGE and Western blotting with both per…
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…
Characterization of cell wall proteins from yeast and mycelial cells of Candida albicans by labelling with biotin: Comparison with other techniques
1992
Candida albicans ATCC 26555 blastoconidia and blastoconidia bearing germ tubes were metabolically labelled by incubating the cells with 14C-labelled protein hydrolysate and were subsequently tagged with biotin. Double-labelled (radioactive and biotinylated) cell wall proteins and glycoproteins were extracted from intact cells of both growth forms by treatment with 2-mercaptoethanol (beta ME) and with beta-glucanases (Zymolyase) after treatment with beta ME. The beta ME- and Zymolyase-extracts were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotted (immunoblotted) to nitrocellulose paper. Polyacrylamide gels were stained with Coomassie blue and process…
Preliminary characterization of the material released to the culture medium by Candida albicans yeast and mycelial cells.
1995
Culture filtrate concentrates were obtained from Candida albicans yeast and mycelial cells grown in the presence of 14C-protein hydrolysate for radioactive labeling of cellular polypeptides. Both growth forms released to the medium minor but significant amounts of proteinaceous materials. The analysis of culture filtrate concentrates by means of SDS-polyacrylamide gel electrophoresis and fluorography revealed a similar and complex electrophoretic pattern, though some qualitative and quantitative differences between samples obtained from yeast and mycelial cells were observed. Materials released, mostly composed of mannoproteins as shown by their affinity towards concanavalin A, presented (i…
Biomechanics and Pathobiology of Aortic Aneurysms
2011
Biomechanical weakening of the aorta leads to aneurysm formation and/or dissection and total biomechanical failure results in rupture, which is often fatal. The most common aneurysm is the abdominal aortic aneurysm (AAA) whereas thoracic aortic aneurysms (TAA) involve the ascending or descending segments of the aorta. Biomechanical strength of the aorta is maintained in part via balance between the integrity of the aortic medial and adventitial extracellular matrix and the health of the mural cells. From a biomechanical perspective, aneurysms rupture or dissect when wall stresses locally exceed the wall strength. Pathobiologic mechanisms, pre-disposing disorders and variability of patient d…
In Silico Shear and Intramural Stresses are Linked to Aortic Valve Morphology in Dilated Ascending Aorta
2017
Objective/Background: The development of ascending aortic dilatation in patients with bicuspid aortic valve (BAV) is highly variable, and this makes surgical decision strategies particularly challenging. The purpose of this study was to identify new predictors, other than the well established aortic size, that may help to stratify the risk of aortic dilatation in BAV patients.Methods: Using fluid-structure interaction analysis, both haemodynamic and structural parameters exerted on the ascending aortic wall of patients with either BAV ( n = 21) or tricuspid aortic valve (TAV; n = 13) with comparable age and aortic diameter (42.7 +/- 5.3 mm for BAV and 45.4 +/- 10.0 mm for TAV) were compared…
Transcatheter Heart Valve Implantation in Bicuspid Patients with Self-Expanding Device
2021
Bicuspid aortic valve (BAV) patients are conventionally not treated by transcathether aortic valve implantation (TAVI) because of anatomic constraint with unfavorable outcome. Patient-specific numerical simulation of TAVI in BAV may predict important clinical insights to assess the conformability of the transcathether heart valves (THV) implanted on the aortic root of members of this challenging patient population. We aimed to develop a computational approach and virtually simulate TAVI in a group of n.6 stenotic BAV patients using the self-expanding Evolut Pro THV. Specifically, the structural mechanics were evaluated by a finite-element model to estimate the deformed THV configuration in …
On the severity of aortic stenosis in ascending aortic aneurysm: A computational tool to examine ventricular-arterial interaction and aortic wall str…
2020
Abstract An ascending thoracic aortic aneurysm (ATAA) is a life-threatening cardiovascular consequence of vessel dilatation that portends adverse events and death. From a clinical perspective, ATAA should not be treated as an isolated disease, and surgery is often carried out in the presence of AS, aortic insufficiency or a calcified valve leaflet. Aortic stenosis (AS) is common in ATAAs and leads to both vessel rigidity and left ventricular (LV) impairment. In this study, lumped-parameter modeling and computational analysis were used to assess the change in the wall shear stress (WSS) and intramural wall stress of patient-specific ATAA models with different degrees of AS (i.e., mild to sev…