Cell Wall Glucans of the Yeast and Mycelial Forms of Paracoccidioides brasiliensis
01 Mar 1970-Journal of Bacteriology (American Society for Microbiology)-Vol. 101, Iss: 3, pp 675-680
TL;DR: The alkali-insoluble glucan of the M form of Paracoccidioides brasiliensis was identified as a beta-glucan which contains a beta-(1 --> 3)-glycosidic linkage by infrared absorption spectrum, by effect of beta-1,3- glucanase, and by partial acid hydrolysis.
Abstract: Glucans were isolated from the cell wall of the yeast (Y) and mycelial (M) forms of Paracoccidioides brasiliensis. The alkali-soluble glucan of the Y form had properties of alpha-1,3-glucan. The alkali-insoluble glucan of the M form was identified as a beta-glucan which contains a beta-(1 --> 3)-glycosidic linkage by infrared absorption spectrum, by effect of beta-1,3-glucanase, and by partial acid hydrolysis. The alkali-soluble glucans of the M form were a mixture of alpha- and beta-glucans and the ratio of alpha- to beta-glucan was variable, depending on the preparations.
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TL;DR: Advances in carbohydrate chemistry have enabled us to move from the foundation of composition analysis to more rapid characterization of specific structures, which will lead to a greater understanding of how fungi coexist with their hosts as commensals or exist in conflict as pathogens.
Abstract: Although fungi have always been with us as commensals and pathogens, fungal infections have been increasing in frequency over the past few decades. There is a growing body of literature describing the involvement of carbohydrate groups in various aspects of fungal disease. Carbohydrates comprising the cell wall or capsule, or as a component of glycoproteins, are the fungal cell surface entities most likely to be exposed to the surrounding environment. Thus, the fungus-host interaction is likely to involve carbohydrates before DNA, RNA, or even protein. The interaction between fungal and host cells is also complex, and early studies using whole cells or crude cell fractions often produced seemingly conflicting results. What was needed, and what has been developing, is the ability to identify specific glycan structures and determine how they interact with immune system components. Carbohydrate analysis is complicated by the complexity of glycan structures and by the challenges of separating and detecting carbohydrates experimentally. Advances in carbohydrate chemistry have enabled us to move from the foundation of composition analysis to more rapid characterization of specific structures. This, in turn, will lead to a greater understanding of how fungi coexist with their hosts as commensals or exist in conflict as pathogens.
177 citations
TL;DR: The biochemical and morphological changes of the yeastlike (Y) form to the mycelial (M) form of Paracoccidioides brasiliensis were examined and a hypothesis for the production of the M form from the Y form is proposed.
Abstract: The biochemical and morphological changes of the yeastlike (Y) form to the mycelial (M) form of Paracoccidioides brasiliensis were examined. The main polysaccharide of hexoses of the Y-form cell wall was alpha-glucan, whereas the polysaccharides of the M-form cell wall were beta-glucan and galactomannan. The alpha-glucan of the Y form contained mainly alpha-(1 --> 3)-glycosidic linkage. The beta-glucan of the M form contained mainly beta-(1 --> 3)-glycosidic linkage with a few branches at C-6 position. The incorporation of (14)C-glucose into the cell wall glucans showed that synthesis of alpha-glucan decreased rapidly after the temperature of the culture was changed from 37 to 20 C. The synthesis of beta-glucan was augmented at an early stage of the morphological change. The M-form cell wall contained 12 times more disulfide linkage than the Y form. The cell-free extracts of the whole cell of the Y form had five times more protein disulfide reductase activity than the M form, whereas extracts of the M form contained five to eight times more beta-glucanase activity than the Y form. From these results, a hypothesis for the production of the M form from the Y form is proposed.
138 citations
TL;DR: The existence of some relationship between the presence of alpha-1,3-glucan in the cell wall of the yeastlike form of Paracoccidioides brasiliensis and the pathogenicity of this fungus is suggested.
Abstract: The yeastlike form of Paracoccidioides brasiliensis strain IVIC Pb9 reduced the amount of alpha-1,3-glucan in its cell wall from 45 to 3% when subcultured in vitro for several years. This strain regained its alpha-1,3-glucan up to 25% of the total cell wall when grown in vivo. A mutant strain of P. brasiliensis Pb9, named IVIC Pb140, reported to have 1,3-mannan instead of alpha-glucan in the cell wall, could not be recovered from experimentally infected animals. The existence of some relationship between the presence of alpha-1,3-glucan in the cell wall of the yeastlike form and the pathogenicity of this fungus is suggested in this report.
109 citations
TL;DR: The pathogenic fungi included in this review are classified according to their cell wall structure, following Bartnicki-Garcia's criteria (15) on the distribution of the two major polysaccharides within the fungal cell wall.
Abstract: The ability of some fungi to cause disease in animals, and particularly in humans, appears to be related to some peculiar trait of their metabolism not shared by taxonomically related species, so that among thousands of species of fungi, only some 100 are considered pathogenic for humans. Recently, there has been an increase in the basic research aimed at elucidating the physiology, biochemistry, and mechanisms of pathogenicity of the fungi in addition to the responses of the infected host. The results from these studies are often difficult to compare because of the lack of reference cultures, and because variability among laboratories are found for many parameters such as origin of isolates, growth conditions, and fractionation procedures used to obtain chemically defined components of cell walls. This review deals with cell wall structures and their influence in host-parasite relationships in those relatively few pathogenic fungi on which substantial literature exists. Serological properties of the walls are included when available. Readers interested in medical and biological aspects of fungi may consult Rippon's (140) and Emmons et al.'s (51) textbooks, among others. Some reviews on microbial surfaces and their relationships to pathogenicity have been published (160 162)2 The pathogenic fungi included in this review are classified according to their cell wall structure, following Bartnicki-Garcia's criteria (15) on the distribution of the two major polysaccharides within the fungal cell wall. This classification is based on the fact that fungi may be subdivided into various categories according to the chemical nature of their walls, and that these categories closely parallel conventional taxonomic boundaries. As seen in Table l, this classification is based on dual combinations of those polysaccharides which appear to be the principal component of vegetative walls, disregarding the presence of small amounts of other classifying polysaccharides. The few pathogenic fungi whose cell walls have been studied to some extent belong to Bartnicki-Garcia's categories 5 (chitin-glucan) and 6 (mannan-glucan) (Table 2). Besides these main polysaccharides, some minor components of the cell wall may also play important roles in pathogenicity, as antigens, or as virulence factors, and they will be mentioned in this review.
98 citations
TL;DR: It was shown that FTIR microspectroscopy is a rapid and accurate tool to simultaneously probe the major biochemical events associated with the autolytic process and the intrinsically higher sensitivity of ATR with respect to transmission spectra in analyzing autolysis was also demonstrated.
96 citations
References
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7,125 citations
"Cell Wall Glucans of the Yeast and ..." refers background in this paper
...Chemical analyses and paper chromatographic studies were performed as described before (12), except for the determinations of total phosphorus (5) and amino acids (20)....
[...]
5,607 citations
TL;DR: Modifications are introduced, based on a test given by Feigl for reducing sugars, which eliminate the heating step, and in which the reagents are applied in organic solvents, thus removing the danger of migration of the sugar spots.
Abstract: THE ammoniacal silver nitrate spray1 used for the detection of sugars has several disadvantages; to those mentioned by Partridge2 should be added the necessity for very careful control of the heating step, particularly important in laboratories lacking special apparatus. We have introduced modifications, based on a test given by Feigl3 for reducing sugars, which eliminate the heating step, and in which the reagents are applied in organic solvents, thus removing the danger of migration of the sugar spots. The method has been in use for more than a year, and has proved easy to handle and extremely reliable.
3,526 citations
"Cell Wall Glucans of the Yeast and ..." refers background in this paper
...Sugars were detected with alkaline silver nitrate (18)....
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TL;DR: A systematic review of the ninhydrin colour test for amino-acids is given in this article, with a note on its use in the identification of protein hydrolysates.
Abstract: A systematic review of the mechanism and application of the ninhydrin colour test for amino-acids, with a note on its use in the identification of protein hydrolysates. -- AATA
1,967 citations
"Cell Wall Glucans of the Yeast and ..." refers background in this paper
...Chemical analyses and paper chromatographic studies were performed as described before (12), except for the determinations of total phosphorus (5) and amino acids (20)....
[...]
1,528 citations
"Cell Wall Glucans of the Yeast and ..." refers background in this paper
...,3-Glucans which have ,B-(1 -* 3)- and ,B(1 -÷ 6)-glycosidic linkages are widely distributed in fungal cell walls (4), and a-1, 3-glucans are now found in various fungal cell walls (2)....
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