Iodide Transport: Inhibition by Agents Reacting at the Membrane (original) (raw)
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Eukaryotic Cell, 2013
Some of the most devastating plant and animal pathogens belong to the oomycete class. The cell walls of these microorganisms represent an excellent target for disease control, but their carbohydrate composition is elusive. We have undertaken a detailed cell wall analysis in 10 species from 2 major oomycete orders, the Peronosporales and the Saprolegniales, thereby unveiling the existence of 3 clearly different cell wall types: type I is devoid of N-acetylglucosamine (GlcNAc) but contains glucuronic acid and mannose; type II contains up to 5% GlcNAc and residues indicative of cross-links between cellulose and 1,3--glucans; type III is characterized by the highest GlcNAc content (>5%) and the occurrence of unusual carbohydrates that consist of 1,6-linked GlcNAc residues. These 3 cell wall types are also distinguishable by their cellulose content and the fine structure of their 1,3-glucans. We propose a cell wall paradigm for oomycetes that can serve as a basis for the establishment of cell wall architectural models and the further identification of cell wall subtypes. This paradigm is complementary to morphological and molecular criteria for taxonomic grouping and provides useful information for unraveling poorly understood cell wall carbohydrate biosynthetic pathways through the identification and characterization of the corresponding enzymes.
The chemistry and molecular architecture of the cell walls of Penicillium chrysogenum
The Journal of biological chemistry, 1969
Treatment of 1%~uniformly labeled cell walls of Penicillium chrysogenum with chitobiase-containing chitinase resulted in 73 % solubilization. The solubilized components were isolated, identified, and determined quantitatively. N-Acetylglucosamine (GIcNAc) and N,N'-diacetylchitobiose ((G~cNAc)~) accounted for 42% of the cell wall. Since kinetic analysis showed that GlcNAc arose from (GlcNAc)t, at least 42% of the cell wall contains GlcNAc in p-~-(1-f 4)glycosidic linkage. When the same experiment was performed with a chitobiase-free chitinase preparation nearly identical results were obtained, except, as expected, essentially all of the GlcNAc was present as (GlcNAc)p. Small amounts of glucose and laminaritriose were also released. In addition, a nondialyzable component, Fraction SA, accounting for 14% of the wall, was isolated. This fraction, devoid of GlcNAc, contains 20 times the amount of galactose and 2 times the amount of mannose with respect to glucose found in cell wall hydrolysates. An additional 13% of the wall was solubilized when the cell wall residue, following treatment with chitinase, was treated with chitinase-free p-~-(1 + 3)-glucanase. Therefore, 86% of the wall was solubilized when treated first with chitinase, then with p-~-(1-+ 3)-glucanase. Initial treatment of cell walls with p-~-(1 + 3j-glucanase resulted in 48% solubilization. From an analysis of the solubilized components the conclusion was reached that at least 40% of the wall contains glucose in ,I!?-D-(1 + 3)glycosidic linkage. An additional 44% of the wall was solubilized when the residue, following treatment with p-~-(1-f 3)-glucanase, was treated with chitinase. Thus, 92% of the wall was solubilized when treated first with p-~-(1 + 3)-glucanase, then with chitinase. The observations that @-D-(1 + 3)-glucanase-free chitinase released in addition to GlcNAc and (GlcNAc)s also glucose, laminaritriose, and a fraction containing mannose, galactose, and glucose (Fraction 5A) and that treatment of this fraction with p-~-(1 + 3)-glucanase released glucose and laminaribiose suggest that glucose may exist in cell
Canadian Journal of Microbiology, 1992
Several probes were used in this ultrastructural study to localize polysaccharides in cell walls on conidial germ tubes, hyphal bodies, and mycelia of the entomogenous hyphomycete Nomuraea rileyi. With the exception of galactose, labelling patterns did not vary from one morphological stage to another. Galactose, which was localized by using a monoclonal antibody to a galactose-specific lectin purified from insect larval hemolymph, was absent from cell walls of hyphal bodies and conidia but was present on germ-tube and mycelial surfaces. Chitin (N-acetylglucosamine), labelled with a wheat-germ agglutinin-ferritin conjugate, was present in the middle regions of lateral walls and septa, and β1-4 glucans were located in the middle and inner regions, as indicated by binding of a cellulase-gold conjugate. An anti-laminaribiose antibody was used to label β1-3 glucans present in the outer wall areas and inner regions near the plasmalemma. The location of mannose residues as indicated by con...
The Storage Glucan of Phaeocystis Globosa (Prymnesiophyceae) CELLS1
Journal of Phycology, 1996
'4 n o i i-r o l~i i~; f~r~i i i~i g nseiiic strniii ofphaeocystis globosa (Ha riot) Lagei-heiin m s shorii to produce n iiwtersolitble @-D-glucnii. ThiJ glitmi? coiisisted of about 20 gluroJe ct)iit>, t n n i i i l~ (l+?)-lidwd, iclith bra iichiiig at positioii 6. Therefore, it caii he classcjed us n c h i y o l a mi i m r n t i. Glucnii productioii occurred uiniiilj during the stntioiin t ;~ groz'th phase niid resulted iji conceiifratioiis ns high (I~J 76 pg glucose per re[/. Il'heii cultures were depriiled of light thvg1ucnti.q u'vre roiisuineci, which sup,borts their possible role ns rovipouucls rtjedfor temporor! storage Kej iudes iclorrl~: ciutofluoresceiice; aseiiic)ioii-coloii>fo r i i i e r ; cci rhohjdrn te prod uctioii; cli rjsolci iii i u n r n i i ; Phaeocystis globosa: P r y iiesiophyene; storage glucn 11s 0 f P)1 P rg1.
Molecular organization of the alkali-insoluble fraction ofAspergillus fumigatus cell wall
Journal of Biological …, 2000
Physical and biological properties of the fungal cell wall are determined by the composition and arrangement of the structural polysaccharides. Cell wall polymers of fungi are classically divided into two groups depending on their solubility in hot alkali. We have analyzed the alkali-insoluble fraction of the Aspergillus fumigatus cell wall, which is the fraction believed to be responsible for fungal cell wall rigidity. Using enzymatic digestions with recombinant endo--1,3-glucanase and chitinase, fractionation by gel filtration, affinity chromatography with immobilized lectins, and high performance liquid chromatography, several fractions that contained specific interpolysaccharide covalent linkages were isolated. Unique features of the A. fumigatus cell wall are (i) the absence of -1,6-glucan and (ii) the presence of a linear -1,3/1,4-glucan, never previously described in fungi. Galactomannan, chitin, and -1,3-glucan were also found in the alkali-insoluble fraction. The -1,3-glucan is a branched polymer with 4% of -1,6 branch points. Chitin, galactomannan, and the linear -1,3/1,4-glucan were covalently linked to the nonreducing end of -1,3-glucan side chains. As in Saccharomyces cerevisiae, chitin was linked via a -1,4 linkage to -1,3-glucan. The data obtained suggested that the branching of -1,3-glucan is an early event in the construction of the cell wall, resulting in an increase of potential acceptor sites for chitin, galactomannan, and the linear -1,3/1,4-glucan.
Composition of the cell wall polysaccharides in some geophilic dermatophytes
Mycopathologia, 1993
The main polysaccharide fractions from cell wall material of several geophilic dermatophyte species were characterized as a glucomannan (FIS) which amounted to 4.0-6.5% and a glucan-chitin complex representing 44.2-71.0%. The neutral sugar content of fraction F1S in these species was mannose (38.7-78.2%), galactose (0.3-7.3%) and glucose (3.2-8.2%) except in M. fidvum (2.1.9%) and E. stockdaleae (12.5%). Small proportions of xylose, about 1%, were found in this fraction except in M. fuIvum which reached 7.8% and in M. nanum which lacked xytose. The main products detected after Smith degradation were glycerol and glucose. From fraction F1S of M. fulvum a glucan (18.3%) and a mannan (41.5%) were obtained. These two polysaccharides could be used as chemotaxonomic characters for the definition of this group of fungi.