A cellulase from the symbiotic intestinal flagellates of termites and of the roach, Cryptocercus punctulatus
Year: 1932
Type: article
Abstract: THE number of organisms able to utilise cellulose as the sole source of carbo- hydrate is small, and the number from which it has been possible to isolate a cellulase is smaller still.Karrer et al. [1923; 1924; 1925] have done extensive work with a cellulase from the intestinal juice of the vineyard snail, as have Pringsheim and Bauer [1928] and Pringsheim and Leibowitz [1928] with a very similar enzyme obtained from malt.Boynton, Lyman and Miller [1927] were able to demonstrate cellulase somewhere in the anterior portion of the ship- worm, Bankia setacea.Jewell and Lewis [1918] found lichenase in the ali- mentary system of each of twenty species of invertebrates.Since lichenin is a form of cellulose [Karrer, Joos and Staub, 1923] the active extracts from these animals would probably also have hydrolysed cellulose.Pringsheim [1912; 1919] showed long ago the presence of a cellulase in cellulose-fermenting bacteria, but this enzyme loses its activity very soon after the death of the bacteria, and has never been obtained in a cell-free condition.Of all the cellulose-feeding organisms there are few whose diet contains as high a percentage of cellulose as does that of termites.Cleveland [1923; 1924] has shown that these insects can live for long periods of time on a diet of almost pure cellulose, if, and only if, their normal complex intestinal fauna has not been removed.This fauna consists mainly of representatives of two orders of flagellates: the polymastigotes and the hypermastigotes.The great majority of these intestinal protozoa ingest cellulose particles and apparently digest them.They might be presumed to contain a cellulase.Most termites, on account of their small size, do not furnish very good material for the preparation of enzyme extracts.Recently, however, it has been discovered that the large wood-feeding roach, Cryptocercus punctulatus, possesses a fauna of intestinal flagellate symbionts very similar in all respects to those of termites [Cleveland, 1930].These roaches, obtained through the kindness of Dr L. R. Cleveland, proved to be an excellent source of the enzyme, cellulase, and they were used for most of the work reported in this paper.The
Source: Biochemical Journal
DOI: 10.1042/bj0261762
Author: William Trager
Institution: Harvard University
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
Funder: Harvard University
OpenAlex ID: W1868580213