LX1V.-The Chemical Action of Bacillus coli cornmu?tis and Similar Organisms on Carbohydrates and Allied Compounds. By ARTHUR HARDEN,THE following experiments were undertaken with the object of examining quantitatively the mode of action of the organisms of the Colon group as fermentative agents, in the hope of finding some characteristics which might serve as a means of classification or discrimination. The organisms of this group can scarcely be distinguished microscopically, but are found to vary in their action on various sugars and proteid compounds. The .Bacillus coli commurzis, a t one end of the series, has the following characteristic properties : ( a ) It decomposes glucose with production of (1) acid and (2) gas. ( b ) It curdles milk. (c) It produces indole from peptone.The Bacillus typho8us, which m a y be taken as the other extreme of the series, does not possess properties b and c, and decomposes glucose with production of acid, but not of gas. Intermediate in the series are a number of organisms, which possess one or more, but not all, of the properties of 23. coli communis or 8. typhosus.The action of B. coli communis and of B. typhosus on glucose has
1. Effect of the addition of Boiled and Filtered Yeast-juice on the Fermentation of Glucose Produced by Yeast-juice . In the course of some experiments on the action of various proteids on the fermentative activity of yeast-juice, it was observed that the alcoholic fermentation of glucose by yeast-juice which has been boiled and filtered, either when fresh or after having undergone autolysis, although this boiled liquid is itself incapable of setting up fermentation. Thus, the total fermentation produced when a greater volume is added, the sugar concentration being kept constant. A similar observation was previously made by Buchner and Rapp in a single experiment (No. 265).
In a previous communication the authors have shown* that when a soluble phosphate is added to a fermenting mixture of glucose and yeast-juice the following phenomena are to be observed : (1) The rate of fermentation is at once greatly increased. (2) This acceleration lasts for a short time and the rate then falls off, and returns approximately to its original value. (3) During this period the extra amount of carbon dioxide evolved and alcohol produced are equivalent to the phosphate added. (4) The phosphate is converted into a form which is not precipitable by magnesia-mixture, and is then probably present as a salt of a hexosephosphoric acid.(1) Effect of the Addition of Phosphate on the Total Fermentation.
THE occurrence in the yeast cell of a substance which yields a reddishbrown coloration with iodine appears to have been first observed by Errera in 1882 (L'EpipZasnze dcs Ascomyc8te.s et Ze Glycogdne des vgqgttaux, Bruxelles, 1885, and Compt. Tend., 1885, 101, 253), although the existence of a carbohydrate reserve substance had been surmised by Pasteur in 1859. On account of this reaction, it was considered to be glycogen, and Errera attempted to extract it from the cell, but did not succeed in obtaining it sufficiently pure t o be certain of its identity with ordinary glycogen.It was next examined by Cremer (Munchener Med. Wochenschr., 1894, 41, 525), who stated that he prepared it from yeast and purified it by Briicke's method (precipitation of the proteids by potassium mercuriiodide) and by fractional precipitation, 13 grams being obtained from 250 grams of dried yeast. He describes it as a neutral white powder, of specific rotation [ a ID + 198.9". It gave a red coloration with iodine, formed a n opalescent solution in water, was converted by boiling with 1225 dilute hydrochloric acid into dextrose, and was inverted by saliva, pancreatic juice, and diastase, A much more detailed investigation on this subject was made by Clautriau (Etude chirnique du Glycogdne. Mem. Coummgs, Acud. Roy. Belg., 1895, 53), who prepared glycogen from yeast, from two species of fungi, and from the rabbit, and carefully compared their properties. Clautriau made use of yeast which had been enriched in glycogen by treatment with wort containing 1 2 per cent. of cane-sugar, and after repeatedly boiling it with ' 1 per cent. aqueous potash and washing with water disintegrated the cells by making them into a solid mass with silica, chalk, and potassium silicate, and then grinding the whole to a fine powder. The glycogen was then extracted by boiling water, a,nd was freed from mucilaginous matters by the repeated production in its solution of a precipitate of calcium phosphate, the last traces of gum being removed by saturating the solution with salt and then adding ammonium sulphate in excess. The glycogen was precipitated from the diluted solution by an excess of iodine, the precipitate treated with sulphurous acid, and the glycogen precipitated by the addition of two volumes of alcohol, and finally washed with absolute alcohol and ether and dried in the air. He thus obtained it free from nitrogen, but containing 1-3-15 per cent. of ash, and observed that in its general properties it agreed with the substance described by Cremer.
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