Showing papers on "Chitin published in 1972"
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TL;DR: A sensitive colour reaction is described for estimating fungi which contain chitin, the glucosamine residues of which are susceptible to deamination with nitrous acid, which yields an aldehyde which is determined colorimetrically with 3-methyl-2-benzothiazolone hydrazone.
Abstract: A sensitive colour reaction is described for estimating fungi which contain chitin. The method is based on the alkaline deacetylation of chitin to chitosan, the glucosamine residues of which are susceptible to deamination with nitrous acid. This yields an aldehyde which is determined colorimetrically with 3-methyl-2-benzothiazolone hydrazone. The observed level of aldehyde, expressed as glucosamine, was related to fungal dry weight by experiments using different fungi grown in vitro. The method, requiring 5 h to complete, has been tested on five phytopathogenic fungi and three hosts, and should be applicable to a wide range of host-pathogen systems.
345 citations
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TL;DR: This antibiotic inhibited the growth of both the yeast and mycelial forms of M. rouxii and caused some minor morphological alterations but did not decisively affect the pattern of dimorphic development.
Abstract: Summary: Polyoxin D is a strong inhibitor of growth and spore germination of Mucor rouxii. This antibiotic inhibited the growth of both the yeast and mycelial forms of M. rouxii. It caused some minor morphological alterations but did not decisively affect the pattern of dimorphic development. Polyoxin D is a powerful competitive inhibitor of chitin synthetase (K
i, = 0·6 μm). Organisms growing at inhibitory concentrations of the antibiotic exhibited weakened walls that were susceptible to bursting.
91 citations
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TL;DR: Findings suggest that the ancestral forms of Mollusca may have had a cuticle without calcified parts, consisting mainly of proteins, mucopolysaccharides and chitin, as well as in the radulae of ten species of the following groups.
Abstract: 1. 1. The cuticle of four species of Solenogastres and Caudofoveata (“Aplacophora”) contains chitin. 2. 2. The tegmentum and articulamentum of the plates of three species of Polyplacophora gave a positive chitosan reaction. 3. 3. Surprisingly chitin was found in the calcified layers of the shells of nine species of Archaeogastropoda, mainly Trochacea, and a taxodont mussel, Nucula nitida . 4. 4. When a well-developed periostracum was present in Gastropoda and Lamellibranchia, especially in the fresh-water and land species, it contained chitin. 5. 5. Chitin was present in the radulae of ten species of the following groups: Placophora (three), Gastropoda (five), Scaphopoda (one) and Cephalopoda (one). 6. 6. Electron micrographs of chitin-containing material which had been treated with KOH showed microfibrils, being arranged in a dispersed texture, sometimes forming bundles, or in a more or less developed parallel texture. 7. 7. These findings suggest that the ancestral forms of Mollusca may have had a cuticle without calcified parts, consisting mainly of proteins, mucopolysaccharides and chitin.
82 citations
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TL;DR: Thirty-seven species of marine invertebrates from different systematic and ecological position were quantitatively tested for cellulase and chininase activity in their digestive systems, and Ascidia Halocyntia aurantium and Metridium senile fimbriatum were found to possess the highest chitin enzyme activity.
Abstract: 1. 1. Thirty-seven species of marine invertebrates from different systematic and ecological position were quantitatively tested for cellulase and chininase activity in their digestive systems. 2. 2. Enzymes were tested by several methods. Carboxymethlcellulase (CMC-ase) and carboxymethylchitinase (CMCh-ase) activities were estimated by the decrease in viscosity of these solutions and by the increase of the reducing sugars. Chitinase activity by precipitated chitin (PCh) was tested by the simultaneous measurement of the reducing sugar (RS) and N-acetylglucosamine (NAGA) in an incubation mixture and by chitin (Ch), using the last method only. 3. 3. Ascidia Halocyntia aurantium and Metridium senile fimbriatum were found to possess the highest chitinase activity; mollusca Littorina mandschurica and L. brevicula had the highest cellulase activity.
77 citations
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TL;DR: On the basis of organic phosphorus content, considerably more phospholipid is associated with the alpha-linked glucan of the more virulent KL-1 strain, suggesting that this cell wall constituent might be one of the factors related to the virulence of this fungus.
Abstract: Cell walls isolated from two strains of Blastomyces dermatitidis were examined. Whereas strain Ga-1 was practically avirulent for mice, strain KL-1 produced death by 21 days in 50% of the mice inoculated. Analyses of the trypsin-treated cell walls of the two strains revealed a higher chitin and protein content in strain KL-1, whereas a higher polysaccharide content was observed in the cell walls of strain Ga-1. Extraction of the walls with 1 n NaOH revealed a threefold difference in the amount of alkali-soluble cell wall material present. The alkali-soluble material could be further fractionated into a water-soluble and a water-insoluble fraction. Previous reports have indicated that the water-insoluble fraction of B. dermatitidis consists of an alpha-linked glucan; however, we report that in addition a phospholipid moiety is covalently bound to the polysaccharide. Furthermore, on the basis of organic phosphorus content, considerably more phospholipid is associated with the alpha-linked glucan of the more virulent KL-1 strain. These results suggest that this cell wall constituent might be one of the factors related to the virulence of this fungus.
55 citations
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TL;DR: In this paper, the content of glucosamine in the walls of daughter (without bud scars) and mother (multiscar) cells ofSaccharomyces cerevisiae was examined in a control and after treatment with dilute alkali, acid and buffer.
Abstract: The content of glucosamine in the walls of daughter (without bud scars) and mother (multiscar) cells ofSaccharomyces cerevisiae was examined in a control and after treatment with dilute alkali, acid and buffer. The occurrence of chitin in the bud and birth scars is discussed. The results of IR and X-ray analysis of cell-wall fractions indicate the presence of α-chitin which is a part of the chitin-glucan complex. The size of the crystallite of α-chitin in this complex is about 60 A.
38 citations
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TL;DR: T4 lysozyme has been purified to apparent homogeneity from lysates of T4-infected Escherichia coli B cells and Binding of the enzyme to chitin under suitable conditions was found to be very efficient and complete, depending on the pH and ionic strength of the medium.
Abstract: T4 lysozyme has been purified to apparent homogeneity from lysates of T4-infected Escherichia coli B cells. In the purification procedure advantage was taken of the affinity of the enzyme for chitin. Binding of the enzyme to chitin under suitable conditions was found to be very efficient and complete, depending on the pH and ionic strength of the medium. The conditions for adsorption and desorption are different from those of hen egg-white lysozyme. The enzyme could be desorbed from the chitin columns by increasing the ionic strength at a low pH.
33 citations
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23 citations
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TL;DR: It is suggested that the hydrolytic capacity of filtrates from cultures of Streptomyces sp.
Abstract: SUMMARY: Walls from Mucor rouxii were partially lysed by an enzymatic complex present in filtrates from cultures of Streptomyces sp. When germinated spores were incubated with the enzymatic complex in a protective medium, osmotically sensitive sphaeroplasts were formed. The enzyme responsible for the degradation of the wall showed optimum activity at pH 7.5 and 32 °C. It was susceptible to the presence of divalent cations. The enzymatic complex released hexosamines (but no N-acetyl hexosamines), neutral sugars and uronic acids from purified walls of the fungus. A wall-bound α-glucosidase was also rendered soluble by the enzyme. The enzymatic complex hydrolysed chitosan, but not chitin or mucoran, and hydrolysed the walls from only fungi belonging to the Mucorales. It is suggested that the hydrolytic capacity of filtrates from cultures of Streptomyces sp. developed in the presence of walls from M. rouxii was due to an enzyme (chitosanase), acting on chitosan but not on chitin.
18 citations
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TL;DR: itin was identified as a wall component by release of N-acetylglucosamine during enzymatic digestions of the walls with Streptomyces griseus chit inase and the presence of chitin in the walls and alkali-insoluble residues was confirmed by X-ray powder analysis.
Abstract: Chemical analyses demonstrated the similar compositions of hyphal walls isolated from the chromomycosis agents Phialophora verrucosa, P. pedrosoi and Cladosporium carrionii. Unfractionated walls of each species consisted of large amounts of glucose (17–31%) and protein components (29–42%) and smaller amounts of mannose (8–14%) and glucosamine (6–8%). Alkali-soluble wall fractions consisted predominantly of glucose and mannose, while alkali-insoluble wall fractions consisted predominately of glucosamine and protein components. Chitin was identified as a wall component by release of N-acetylglucosamine during enzymatic digestions of the walls with Streptomyces griseus chitinase. The presence of chitin in the walls and alkali-insoluble residues was confirmed by X-ray powder analysis. The suggestion is made that the hyphal forms of human pathogenic fungi have wall compositions intermediate between those of euascomycetes and hemiascomycetes.
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TL;DR: Decomposition of chitin by Cytophaga johnsonii was investigated and the nature of some of the products formed and the steps involved in their transformations by the resting cells and the cell-free extracts suggested that N-acetylglucosamine first gets deacetylated to glucosamine before it is further oxidized to glucoaminic acid by these strains.
Abstract: Decomposition of chitin by Cytophaga johnsonii was investigated. Unlike other chitinolytic bacteria, some strains of C. johnsonii did not liberate chitinase extracellularly; instead the cells of such strains had need for close contact with the chitin particles in order to hydrolyze them. The cell-free extract of one of these strains, viz., C. johnsonii C35 did show presence of chitinase. The remaining strains liberated an extracellular chitinase and a chitobiase. The partially purified chitinase from the culture filtrates of C. johnsonii C31 was most active at pH 6.3–6.5 and at 40°C. Metabolism of N-acetylglucosamine, a product of chitin hydrolysis, by C. johnsonii C35 and C31 was investigated. The nature of some of the products formed and the steps involved in their transformations by the resting cells and the cell-free extracts suggested that N-acetylglucosamine first gets deacetylated to glucosamine before it is further oxidized to glucosaminic acid by these strains. Both strains were also able to dehydrogenate gluconate to 2-ketogluconate, the former being in all probability the product of deamination of glucosaminic acid.
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13 Nov 1972
TL;DR: In this paper, a microcrystalline chitin is prepared by subjecting chitins to controlled acid hydrolysis and high shear while suspended in an aqueous medium.
Abstract: Microcrystalline chitin is prepared by subjecting chitin to controlled acid hydrolysis and high shear while suspended in an aqueous medium.
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TL;DR: A high incidence of chitin decomposing bacteria in carp was considered to be related to a better utilization of petro-yeast by carp than by the other freshwater fish.
Abstract: In order to elucidate the reasons for the highly efficient utilization of petro-yeast in freshwater fish, a series of experiments were carried out, laying emphasis on the characteristically high content of chitin in petro-yeast. In this report, the authors examined the distribution of chitin decomposing bacteria in the digestive tracts of ayu (Plecoglossus altivelis), carp (Cyprinus carpo), and rainbow trout (Salmo gairdneri), as well as the biochemical characteristics of the isolated chitin decomposing bacteria. Chitin decomposing bacteria were isolated from the digestive tracts of the above mentioned fishes in relatively high frequencies. The proportion of chitin decomposing bacteria to total bactiria was generally high in every species of fish, particularly in fishes fed with a diet containing petro-yeast. Most of the chitin decomposing bacteria isolated were considered to belong to Ahromonas genus according to their biochemical characteristics. This makes a marked contract with the case of marine fishes whose chitin decomposing bacteria were mainly members of genus Vibrio. In particular, a high incidence of chitin decomposing bacteria in carp was considered to be related to a better utilization of petro-yeast by carp than by the other freshwater fish.
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TL;DR: Cell walls and cell sap of 2 strains of Sepedonium were lipid-extraction and the readily-extracted lipids examined, finding that Mannose and glucose were the only sugars found in the cell walls; much of the glucose was resistant to mild acid hydrolysis.
Abstract: Cell walls and cell sap of 2 strains of Sepedonium were lipid-extracted and the readily-extracted lipids examined. The lipid-extracted cell walls were treated with ethylenediamine, and unfractionated, as well as fractionated, cell walls were analyzed for their sugar and chitin content. The lipids of all preparations consisted of phospholipids, triglycerides, diglycerides, sterols, sterol esters and free fatty acids. Linoleic acid was, with 1 exception, the major fatty acid in all extracts; palmitic, stearic and oleic acids were also present. Mannose and glucose were the only sugars found in the cell walls; much of the glucose was resistant to mild acid hydrolysis. These sugars together accounted for approximately 20% of the unfractionated cell walls of both strains. Glucose and acetylglucosamine were released from the cell walls of both strains by a crude chitinase preparation, and the acetylglucosamine represented 19% and 28% of the cell walls of the 2 strains.