Showing papers on "Chitin published in 1968"

Use of chitin for promoting wound healing

Abstract: WOUND HEALING COMPOSITION AND THE PROCESS OF HEALING WOUNDS WITH SUCH COMPOSITIONS ARE DESCRIBED, THE COMPOSITIONS CONTAINING CHITIN, PARTIALLY DEPOLYMERIZED CHITIN OR A CHITIN DERIVATIVE.

Chitin decomposition in soil: II. The ecology of chitinoclastic micro-organisms in forest soil

Abstract: Decomposition of naturally occurring and artificially buried chitin in a pine forest soil was brought about by fungi, bacteria and actinomycetes. In the acid horizons, Verticillium sp. I, Mortierella marburgensis and Trichoderma viride were the most important chitin decomposers, whilst in the alkaline horizon Mortierella alpina, Paecilomyces carneus, Gliomastix murorum and to some extent Verticillium sp. I predominated. Bacteria and actinomycetes, mainly species of Pseudomonas, Bacillus and Streptomyces , were found in all horizons, but predominated only during the early stages of breakdown in the alkaline horizon. Some chitin decomposers were restricted to chitin and were not found on other soil particles, e.g. Verticillium sp. I and Calcarisporium arbuscula . The survival of these and other forms is discussed in relation to the occurrence of chitin in the soil and the ability of organisms to utilize chitin breakdown products.

Chitin decomposition in soil

Abstract: Media for the isolation of chitinoclastic micro-organisms from soil have been compared. Agar media containing chitin as a sole carbon and nitrogen source were as good as others tested. The chitin in the media was prepared by ball milling shrimp chitin for 48 h at 2 ° C. Addition of antibiotics to the media made them selective for different groups of micro-organisms.

Studies on Amino-hexoses XIV. Preparation of Partially O -Carboxymethylated Chitin and Its Component 3- O - and 6- O -Carboxymethyl- D -glucosamine, and the Corresponding Glucosaminitols

Abstract: 3-O-carboxymethyl-D-glucosamine, 6-O-carboxymethyl-D-glucosamine, and the corresponding glucosaminitols are prepared as reference compounds in a study of a lysozyme action on a partially-O-carboxymethylated chitin. The preparation of partially-O-carboxymethylated chitin, a substrate of hen-egg white lysozyme, is also described.

The cell wall of Penicillium roquefortii.

Abstract: The cell wall of Penicillium roquefortii has been shown to contain predominantly glucan, chitin, and protein. There is no evidence for any mucopeptide-like structure.

Some Properties of Unpurified Chitinase from the Crayfish Plague Fungus, Aphanomyces astaci

Abstract: The culture filtrate of the crayfish plague fungus, Aphanomyces astaci (Saprolegniaceae), incubated in a peptone glucose medium was tested for chitinase activity under different conditions. The activities were assayed turbidimetrically using low-polymerized chitin as a substrate. Adsorption of chitinase was found to occur on chitin and probably on cellulose and sulphomethyl cellulose but not at all or only a little on some other cellulose derivatives. The pH optimum of the enzyme activity was found to lie at about pll 5.0–5.5. The stability was greatest near pH 6.5 and the highest degree of adsorption occurred at still higher pH values. Enzyme adsorption on the substrate seemed to protect the enzyme against inactivation by heating, shaking, and extreme pH-conditions. The chitinase activity was positively affected by the rest of the culture filtrate. Mercury, cobalt, and copper chlorides, and to a lesser degree some other metal salts, lowered the enzyme activity when present in the test medium. Cellobiose, but neither glucose nor N-acetyl glucosamine had a pronounced inhibiting effect on the activity. Neither cellobiose nor N-acetyl glucosamine seemed to affect chitinase adsorption on chitin. Some chelating and reducing compounds inactivated the culture filtrate. This activity-reducing effect of chelators was strongly prevented by EDTA in some cases.

Studies on the substrate specificity of egg white lysozyme. II. Mode of the enzymatic action on partially-O-carboxymethylated chitin.

Abstract: Partially-O-carboxymethylated chitin was found to be a soluble substrate of hen egg white lysozyme. The products of the lysozyme action were analyzed by gel filtration and by ion-exchange chromatography. The reducing ends of the saccharides produced by the enzyme were the N-acetyl-glucosamine residue or the 3-O-carboxymethyl-N-acetyl-glucosamine residue. 6-O-Carboxymethyl-N-acetyl-glucosamine never appeared as a reducing end. The O-substituted disaccharide detected in the reaction products was 6′-O-carboxymethyl-di-N-acetyl-chitobiose. The results of the reducing-end analyses and the finding that none of the monomers were formed except for the unsubstituted N-acetyl-glucosamine, while an O-substituted dimer was formed as is mentioned above, are in conformity with the conformation of the enzyme-substrate complex proposed by Blake et al. as a result of their X-ray crystallographic investigations.