Showing papers on "Chitin published in 1974"
TL;DR: Housefly larvae of 2 days of age were allowed to grow in media containing 0, 0.4, 1.0, or 2.5 ppm TH 6040 for 3 days prior to analysis of the cuticle for structural components ( chitin and protein) or enzymes important in cuticle formation (chitinase and phenoloxidase).
210 citations
TL;DR: A microautoradiographical study was made of the incorporation of glucose, tyrosine, and proline in endocuticle of fifth-instar larvae of Pieris brassicae L..
191 citations
TL;DR: An enzyme which hydrolyzes the acetamido groups of N-acetylglucosamine residues in chitin was partially purified from Mucor rouxii and accounts for the formation of chitosan in fungi.
111 citations
TL;DR: Chitin, the naturally occurring polymer of N-acetyl-glucosamine, has been used as a ligand matrix for affinity chromatography of wheat germ agglutinin in a new purification method which is well suited for large scale preparations.
107 citations
TL;DR: The normal sequence of cell separation in Saccharomyces cerevisiae begins with the formation of a primary septum, presumably consisting of chitin, on which secondary septa are later deposited, but in the presence of the antibiotic polyoxin D this sequence is disrupted.
Abstract: The normal sequence of cell separation in Saccharomyces cerevisiae begins with the formation of a primary septum, presumably consisting of chitin, on which secondary septa are later deposited. In the presence of the antibiotic polyoxin D, a potent inhibitor of chitin synthetase, pairs of abnormal cells of two different types were observed by phase-contrast microscopy: the “exploded pair,” consisting of two lysed cells from which the cytoplasm had been extruded at the cell junction, and the “refringent pair,” consisting of two highly refractile cells joined by a thin bridge. Thus, in both cases the septal region appears to be affected. Observations with the electron microscope showed that the primary chitin septum was not formed in either of these cell types, and as a consequence secondary septa of varying thicknesses were laid down in an abnormal pattern. With [ 3 H]glucose as carbon source the incorporation of tritium into the chitin of abnormal cells was inhibited about 90%, whereas the labeling of mannan was normal and that of glucan somewhat reduced. The effective concentrations of polyoxin D (0.1 to 1 mg/ml) were much greater than those required to inhibit chitin synthesis in vitro. Dimethylsulfoxide and amphotericin B, both known to increase cell permeability, enhanced the action of the antibiotic. Images
95 citations
TL;DR: A "soluble" form of chitin synthetase was separated from a membrane-rich fraction by exposure to the enzyme substrate (uridine diphosphate N-acetyl-D-glucosamine) and activator (Nacetyl, D-glocosamine), which catalyzed the synthesis of microfibrils similar, if not identical, to those formed by the fungus as discussed by the authors.
Abstract: A "soluble" form of chitin synthetase was separated from a membrane-rich fraction by exposure to the enzyme substrate (uridine diphosphate N-acetyl-D-glucosamine) and activator (N-acetyl- D-glucosamine). The solubilized enzyme catalyzed the synthesis of chitin microfibrils similar, if not identical, to those formed in vivo by the fungus. Cell wall microfibrils were thus abundantly formed in the absence of a living cell or its membranes.
85 citations
TL;DR: This chapter discusses a molecular model for morphogenesis, which considered a group of peptidyl-pyrimidine nucleoside antibiotics from Streptomyces cacaoi that are active against a variety of fungi and considered that their site of action was related to the biosynthesis of cell wall chitin.
Abstract: Publisher Summary This chapter discusses a molecular model for morphogenesis The simplest explanation of the asymmetry that results from cell separation is that the mother cell retains both the primary and secondary septa that go to form the bud scar; the daughter cell retains only a secondary septum, the birth scar If indeed chitin constitutes the primary septum, it should be synthesized during a specific period of the cell cycle, that is, prior to cell division To determine whether this was the case, a synchronous culture of Saccharomyces carlsbergensis was allowed to grow in a medium containing tritiated glucose, and the incorporation into chitin was monitored Both the polysaccharide label and the number of cells increased in stepwise fashion whereas the total radioactivity in the cells increased exponentially Polyoxins are a group of peptidyl-pyrimidine nucleoside antibiotics from Streptomyces cacaoi that are active against a variety of fungi It was considered that their site of action was related to the biosynthesis of cell wall chitin
80 citations
TL;DR: Results suggest that the chitin synthetase is a plasma membrane-bound enzyme that was found in the Phycomyces mycelia of different ages as well as in the sporangiophores of each of the five developmental stages.
73 citations
TL;DR: The results indicate that polyoxin B acts as an competitive inhibitor of chitin synthetase, which is concerned in the synthesis of cell-wall chitIn of A. kikuchiana, and suggest that the polyoxin-resistance of this fungus is caused by a lowered penetration of the antibiotic through the cell membrane into the enzyme site.
Abstract: A large number of strains of Alternaria kikuchiana that cause the black spot disease on pear were isolated from some orchards of Tottori Prefecture, Japan. From them seven strains, which showed different sensitivities to polyoxin B, were selected and used in the experiments. Polyoxin B, at a concentration of 10μM, inhibited more than 50% of the incorporation of glucosamine-14C into cell-wall chitin in washed mycelia of the polyoxin-sensitive strains and at the same time resulted in an unusually increased accumulation of UDP-N-acetylglucosamine-14C, which is a precursor of chitin biosynthesis. Both the inhibition of glucosamine-14C incorporation into chitin and the increase of accumulation of UDP-N-acetylglucosamine-14C caused by polyoxin B were moderately lowered with decreasing the sensitivity to the antibiotic of the different strains. Crude preparations of chitin synthetase were obtained from these strains. Polyoxin B strongly inhibited all the enzyme preparations in competition with their substrate UDP-N-acetyl-glucosamine. The Km values for the substrate or the Ki values for the antibiotic determined in the enzyme reactions differed slightly from each other. These results indicate that polyoxin B acts as an competitive inhibitor of chitin synthetase, which is concerned in the synthesis of cell-wall chitin of A. kikuchiana. And they also suggest that the polyoxin-resistance of this fungus is caused by a lowered penetration of the antibiotic through the cell membrane into the enzyme site.
72 citations
TL;DR: The cell wall of the yeast form of Histoplasma farciminosum contains 13.2% beta-1,3-glucan, 1.0% galactomannan, and 25.8% chitin this article.
Abstract: The cell wall of the yeast form of Histoplasma farciminosum contains 13.2% beta-1,3-glucan, 1.0% galactomannan, and 25.8% chitin, whereas the cell wall of mycelial form has 21.8, 4.5, and 40%, respectively, for the same polymers. Also, the cell wall of the yeast form contains alpha-1,3-glucan (13.5%) and an unidentified polymer (21.5%). Chitin, one of the structural polymers of both yeast and mycelial cell walls, is identified as thin isolated fibers (4 nm wide) or in thick bundles (50 nm wide) of fibers. beta-(1-3)-Glucan is also found as thin isolated fibers indistinguishable from isolated fibers of chitin. Fibers 14 nm wide and resembling alpha-(1-3)-glucan fibers of other fungi are found in the yeast form. The results reported here do not give support to the proposal for a different taxonomic classification.
65 citations
TL;DR: In this article, the cell walls of the yeast-like (Y) and mycelial (M) forms of Histoplasma capsulatum G-184B were analyzed and it was shown that the Y form contained about 46.5% of β-glucan, 31.7% of galactomannan, 25.8% of chitin, and essentially no αglucans.
Abstract: Chemical and ultrastructural studies of the cell walls of the yeastlike (Y) and mycelial (M) forms ofHistoplasma capsulatum G-184B revealed that the Y form contained about 46.5% ofα-glucan, 31.0% ofβ-glucan, 7.7% of galactomannan and 11.5% of chitin, whereas the M form cell wall contained about 18.8% ofβ-glucan, 24.7% of galactomannan, 25.8% of chitin, and essentially noα-glucan. Theα-glucan of the Y form contained mainly anα-(1 → 3)-linkage. Theβ-glucans of both forms may have mainly aβ-(1 → 3)-linkage. Chitin microfibrils were located mainly in the inner portion of the cell walls of the Y and M forms, whereas theα-glucan fibers were observed only in the outer portion of the Y form cell wall.
TL;DR: It is concluded that a small but significient number of the amino groups in the chitin molecule are not acetylated, and the molecular packing of the chains was essentially side-by-side.
TL;DR: A glycol-chitin-splitting enzyme without lysozyme (muramidase) activity was found in serum from various animals and the concentration of the enzyme was determined in various organ tissues and body fluids to elucidate the origin of the serum chitinase.
Abstract: 1. A glycol-chitin-splitting enzyme without lysozyme (muramidase) activity was found in serum from various animals. Goat, cow, hen, sheep and pig possessed high activity. No activity was found in serum from man, monkey, horse, dog, cat, rabbit, guinea-pig or hamster.
2. Glycol chitin has been used as a substrate in purification and characterization. A viscosimetric assay with the use of this substrate was found to be a convenient method.
3. By means of ammonium sulphate fractionation of goat serum and subsequent gel chromatography a 100-fold purification of the enzyme was obtained.
4. The purified enzyme has its optimal activity around pH 1.65 with glycol chitin as a substrate and, when incubated at 50 °C for 60 min, the optimal stability is in the pH interval 3.5–6.5. The pI determined by isoelectric focusing is 4.85 and the molecular weight assessed by gel chromatography is around 60000.
5. The purified goat serum enzyme degrades colloidal chitin with an optimum at pH 5.5 and is thus defined as a chitinase. Goat anti-human lysozyme serum does not inhibit the purified chitinase.
6. To elucidate the origin of the serum chitinase, the concentration of the enzyme was determined in various organ tissues and body fluids. The highest activity with the exception of serum was found in the wall of the fourth stomach of goat and cow.
TL;DR: A new model of the regulation is presented which accounts for the specific location as well as for termination of chitin synthesis during the budding cycle.
Abstract: The activity of chitin synthase extracted from whole cells of Saccharomyces cerevisiae shows reproducible changes during the course of batch cultivation. During exponential growth 5–10% of the enzyme occurs in the active form, whereas in the stationary phase no active enzyme can be detected. Of three yeast proteinases, A, B and C, only B is able to activate pre-chitin synthase and inactivate chitin synthase. A new model of the regulation is presented which accounts for the specific location as well as for termination of chitin synthesis during the budding cycle.
TL;DR: Cell walls of the Basidiomycete fungus Polyporus tumulosus (Cooke) were fractionated, and the polysaccharide content of the fractions investigated, providing supporting evidence that the poly Saccharide is an essentially unbranched polymer of 1,3-linked glucose residues.
TL;DR: From the results of chemical analysis, optical rotation, infrared spectrum and alkaline treatment, it is suggested that the predominant structure for this polysaccharide is (1→4)-2-acetamido-2-deoxy-6- O -sulfo- β -D-glucopyranan.
TL;DR: The cytosol of the sporangiophore of Phycomyces blakesleeanus has considerable chitinolytic activity, and the possibility is discussed that chit inase might be involved in the growth response system by transiently loosening the rigid framework of chitin at specific and defined points.
TL;DR: A study of the chitin contents in Rhodotorula yeast walls indicates that the contents of this amino polysaccaharide may vary from 0.58 to 12% according to the yeast and depending on the culture conditions, which means cell walls with high glucosamine content, but low amino-acids content, are the more easily degraded.
TL;DR: Cell walls from Morchella sp.
Abstract: Cell walls from Morchella sp. were isolated after mechanical breakage of the fungus. Analysis of the material revealed that the most prominent compound was protein, phosphate being present in lesser amounts. Non-nitrogenous polysaccharides accounted for 17%. They were mostly soluble in hot HCl. The following monosaccharides were identified by chromatography of hydrolyzed samples: glucose, mannose and galactose. No lipids were detected in the purified cell walls. Chitin was present in a concentration of 16%. It was identified by cytochemical reactions, infrared spectra, and X-ray diffraction analysis. The cell wall of Morchella did not contain chitosan nor cellulose.
TL;DR: The initial rates of mineralization of chitin by Pseudomonas sp. and soil microorganisms were enhanced in media containing glass microbeads, the extent of stimulation being governed by bead size.
Abstract: The initial rates of mineralization of chitin by Pseudomonas sp. and soil microorganisms were enhanced in media containing glass microbeads, the extent of stimulation being governed by bead size. Size of the glass particles also affected the formation of reducing sugars during chitin decomposition. A thin layer of 29 μm beads placed between the polysaccharide and Pseudomonas sp. almost totally prevented chitin degradation for 15 days, but the attack was retarded somewhat even with glass particles of larger diameter. No decomposition occurred if a thicker layer of small glass spheres was placed between the substrate and the bacterium.
01 Jul 1974
TL;DR: Bacteriophage T7 infected Escherichia coli B cells have been shown to contain two enzyme activities possessing the ability to liberate radioactive material from 3H diaminopimelic acid labelled E. coli C cell walls.
TL;DR: The preparation and use of an affinity adsorbent based on a low molecular weight substrate analog of lysozyme, which could be used for coupling other saccharides to agarose is described.
Abstract: Publisher Summary Affinity chromatography of lysozyme has been carried out using a variety of adsorbents: dispersed chitin, carboxymethylated chitin, deaminated chitin, and chitin-coated cellulose. This chapter describes the preparation and use of an affinity adsorbent based on a low molecular weight substrate analog of lysozyme. The procedure for preparation of the adsorbent is general and could be used for coupling other saccharides to agarose. The experiments described in this chapter were carried out in order to determine optimum elution conditions for handling small amounts of lysozyme such as are manipulated during purification of synthetic protein.
TL;DR: The highest value of incorporation within 24 hours was shown at one day after molting suggesting that the most active synthesis of chitin occurs at the beginning of endocuticle formation and slows down thereafter with the lapse of time.
Abstract: The incorporation of radioactivity into chitin of the exoskeleton after injection of glucose-1-C14 into the blood of a shore crab, Gaetice depressus, was studied in relation to chitin synthesis at stages of the molting cycle.The ratio of chitin to organic matter was determined to be 67.9% in the completed exoskeleton, but different in each cuticle layer; that is, 22.4% in the exocuticle, 74.9% in the endocuticle, and 63.3% in the membranous layer.During the period of endocuticle formation, the radioactivity was rapidly incorporated into chitin within several hours after the injection of glucose-1-C14, while that in blood decreased correspondingly.Throughout the molting cycle, the highest value of incorporation within 24 hours was shown at one day after molting suggesting that the most active synthesis of chitin occurs at the beginning of endocuticle formation and slows down thereafter with the lapse of time.