Glucan cell-wall

Xyloglucans are classified as gum when they are extractable with hot water from seed endosperm cell walls, such as the tamarind seed xyloglucan, and as hemicelluloses because they are alkali-extractable from the cell walls of vegetative plant tissues where they are closely associated with cellulose [2]. Also /3-glucans with mixed linkages appear under the name gum as well as hemicellulose in the literature. 

It may be that this fact was associated with the rather complex composition of fungal mycelium, consisting of chitin enclosed in a glucan matrix (Bowman, Free, 2006). Therefore, mature saprophyte mycelium are completely covered by difficult-soluble glucans and the fraction of chitin in the apical cell wall is not sufficient. As such, we supposed that these cationic isoforms bound with another major component of the fungi... 

Fig. 8. Activation of the PO binding with P, infestans cell walls (glucan-specific ) under pathogen inoculation and treatment with salicylic (SA) and jasmonic (JA) acids (A) Peroxidase activity in stomata guard cells and intercellular spaces of adjoining epidermal leaf cells and on the surface of mycelium contacting with the stomata (B). (1) Non-treated control (2) infection (3) treatment with SA (4) treatment with SA + infection (5) treatment with JA (6) treatment with JA + infection (7) treatment with SA + JA (8) treatment with SA + JA + infection g - gifs of P. infestans s - stomata guard cell. Specific to P, infestans cell walls, PO is highlighted.

Several methylated sugars have been identified in hydrolyzates of LPS, cell-wall polysaccharides, and extracellular polysaccharides. A considerable number of these have been found in the LPS from photosynthetic prokaryotes. Two polysaccharides from Mycobacterium species, a glucan" and a mannan" are remarkable in that they contain high percentages of methylated sugars. Glycolipids from Mycobacterium species are also rich in methylated sugars, some of which have not been found elsewhere, but this is beyond the scope of the present article. 

Manners D.J., Masson A.J. Patterson J.C. (1973a) The sductiwe of a j8-(l-3)-D-glucan fixMn yeast cell walls. BiochemJ, 135, 19-30. 

Sanjuan R., Zueco J., Stock R., Font de Mora J. Sentandreu R. (1995) Identification of glucan-mannoprotein complexes in the cell wall of Candida albicans using a monoclonal antibody that reacts with a (l,6)-/3-glucan epitope. Mzcroftzo/ogy, 141, 1545-1551. 

Intrinsic (natural, innate) resistance. In one form of intrinsic resistance, the fungal cell wall (see Chapter 2) is considered to present a barrier to exclude or, more likely, to reduce the penetration by biocide molecules. The evidence to date is sketchy but the available information tentatively links cell wall glucan, wall thickness and consequent relative porosity to the sensitivity of Saccharomyces cerevisiae to chlorhexidine. 

CelIulose.-Most biologists know that cellulose (l->4-linked P-D-glucan) is a polysaccharide component of all primary and secondary cell walls. Indeed, plant cell walls are... 

IV. PARASITISM. Lysis by hydrolytic enzymes excreted by microorganisms is a well-known feature of mycoparasitism. Chitinase and P-l,3 glucanase (laminarase) are particularly important enzymes secreted by fungal mycoparasites capable of degrading the fungal cell wall components, chitin, and P-1,3 glucan (131-134). 

The cell wall of S. cerevisiae is composed of glucan, mannoproteins, and chitin (Klis, 1994 Cid et al., 1995). Of the mannoproteins, some of them are first synthesized as GPI-anchored and mannosylated proteins. Subsequently, they are incorporated from the plasma membrane to the cell wall and are covalently linked to the glucan there. Therefore, some signals should exist for dictating the cell wall incorporation. One found at a short N-terminal region near the GPI-attached asparagine (the co-site) is important (Hamada et al., 1998b). Namely, a plasma membrane GPI-anchored protein was localized to the cell wall if the (V/I)... 

Table L Synergism between Glucanases in C wriffis lysis (SCL) and Solubilization of Cell Wall Glucans (SCS)...

Table IV. Effect of Sequential Addition of Glucanases on the Lysis and Solubilization of C utilis Cell Wall Glucan...

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