Maltose Solutions Research Articles

A Physiological and Morphological Study of Saprolegnia parasitica

Summary1. Isolations of Saprolegnia parasitica were made from five localities in Michigan and were taken from five species of fish.2. Detailed physiological experiments were made on the mycelium derived from a single spore isolation from white fish eggs obtained from the State Fish Hatchery at Bay City, Michigan. The experiments were made to determine if possible whether or not 5. parasitica was a sterile species as has been supposed.3. It has been shown that the morphology of this fungus can be controlled largely by modifications of the environmental conditions. These modifications are based upon the Klebsian hypothesis that vegetative and reproductive processes can be controlled by a gradual reduction of the nutritive supply.4. Oögonia and antheridia were produced on the mycelium in certain experiments tried. This is the first time that sexual organs have been shown to exist for S. parasitica.5. Peptone was found to be the stimulus for sexual reproduction when used in combination with leucin or with maltose in solution, or with glucose or maltose in synthetic agar. Sexual organs were also produced on mycelium grown on sterilized hemp seed in water.6. The morphological characters are unlike those of other species of the genus and support is thereby given for considering S. parasitica a distinct species.7. The physiological reactions of S. parasitica are unlike those reported for related species and the doctrine of specificity is again confirmed.8. The reactions of the fungus to substrata in nature are discussed. Given a highly concentrated nutritive supply like fish or fish eggs, S. parasitica produces an excellent vegetative growth and reproduces only asexually. Countless chlamydospores are produced as the reaction to a superabundance of food materials. Physiological experiments are reported in which the conditions found in nature are approximated. Conditions causing significant differences in physiological reactions are given in detail.9. A few observations on parasitism are reported.10. An emended description of the species is given.

PRELIMINARY STUDY OF THE NUTRITION OF THE CULTIVATED MUSHROOM

Mushrooms are commercially grown uponl composts of horse manure. As the available supply of manure is becoming less, it is important to explain the wide difference between average and maximum yields. This requires a better knowledge of the nutrition of the cultivated mushroom than we now have. The first attempts to culture Agaricus campestris L. in media of known composition were made by Duggar (2), who made a series of cultures on gray filter paper to which were added various carbonaceous and nitrogenous cornpounds, along with a mineral nutrient solution. His successful cultures included those containing calcium hippurate, peptone, and casein; while the unsuccessful ones were upon the common sugars, starch, mannite, tartrates, lactates, urea, asparagine, ammonium salts, and nitrates. He concluded that the fungus could not utilize carbon in the form of sugars and organic acid salts, nor nitrogen in inorganic form. This conclusion is surprising in view of the general use of these compounds in culture media for fungi. Even the higher fungi have been grown upon such media, Lutz (6) having used a solution of xylose, maltose, ammonium salts, and minerals for hymenomycetes of several types. It is possible that Duggar's negative results were due in part to some adverse condition not easily observed rather than to the inability of the myceliun to develop upon simple nutrients. This possibility was considered in planning the present investigation. Hebert and Heim (4) asserted that calcium and potassium should be added to manures used in the commercial culture of mnushrooms, but supported the assertion only with analyses of mushrooms showing high contents of these elements. Later Hebert and Heim (5) reported that the composting of manure for mushroom culture was marked by losses in ammonia, organic acids, gums, cellulose, and xylan, and by increases in vasculose ( the black materials of the compost) and complex nitrogenous materials. They suggested that the nutrition of the mushroom was dependent upon a supply of the latter groups rather than of the former. Boyer (i), in a study of Agaricuts campestris, transferred his cultures from the original into manure, but said, Almost all organic materials and many inorganic substrata are good. He did not obtain growth upon blotting paper or cellulose; however, it was not stated what medium was used with these materials. Boyer did not mention the inorganic materials used, except to state that potassium nitrate did not improve the growth in

The Hydrolysis of Maltose by Hydrochloric Acid under the Herzfeld Conditions of Inversion

It is shown that contrary to the statements of Kluyver and others, maltose undergoes slight hydrolysis (to the extent of about 2% when 1% solutions of maltose are used) when heated with hydrochloric acid under Herzfeld conditions. It is preferable therefore to adopt 10% citric acid, under the conditions formerly laid down, in estimating cane sugar in plant extracts when maltose is likely to be present.