The Pure Culture of Physarum polycephalum on a Partially Defined Soluble Medium

Abstract

SUMMARYA wild strain of the multinucleate plasmodial myxomycete Physarum polycephalum was isolated in pure culture and grown on a medium consisting of 1 yo (w/v) Tryptone, 1% (w/v) glucose, 0.15% (w/v) yeast extract, 0.3% (w/v) CaCO,, inorganic salts and a small amount of chick embryo extract. The organism may be grown with this medium either as a single large plasmodium on surface culture, or as a suspension of tiny plasmodia in submerged culture. From an initial inoculum of 1 ml. of a %day culture, the average plasmodial yield in a submerged culture was about 80 mg. dry weight/20 ml. medium a t 72 hr. Growth occurred only in the presence of small amounts of an unidentified factor which was present particularly in chick embryo extract and foetal calf serum. An isolate of P. polycephalum was grown continuously on this medium for over four years without an appreciable decrease in growth rate. Under proper conditions a suspension of tiny plasmodia from shaken culture will fuse to form a single large surface plasmodium which exhibits synchronous mitosis.

Nutrition and Chemotaxis in the Myxomycete Physarum polycephalum: the Effect of Carbohydrates on the Plasmodium

“…I . Virtually no lag phase occurred, and growth rate (doubling time about 12 h.) and yield were comparable to, or greater than, the highest reported by other workers (Daniel & Rusch, 1961 ;Daniel & Baldwin, 1964;Brewer, Kuraishi, Garver & Strong, 1964). When glucose was omitted from the standard medium, little growth occurred ( Table I ; Fig.…”

“…The omission of glucose from standard medium results in growth yields of as low as 2 % of those given by control cultures (Table I); this establishes that peptone cannot act as sole carbon source for the growth of Physarum polycephalum. The high yields obtained in the absence of added carbohydrates by earlier workers, 29 % (Daniel & Rusch, 1961) and 36 to 49 % (Daniel & Baldwin, 1964) Nutrition and chemotaxis in a myxomycete 225 of control cultures, are probably due to the presence of large amounts of yeast extract in their media, as are the high yields (52 % of control cultures) obtained with P. rigidum (Henney & Henney, 1968).…”

“…One of the more convincing of the early studies was that of Coman (I940), who found that plasmodia of Physurum polycephalum Schweinitz responded to glucose solutions by positive chemotaxis but were indifferent to sucrose solutions. Since this study, the pure culture of plasmodia of P. polycephalurn on liquid media has been achieved (Daniel & Rusch, 1961). It therefore seemed desirable to confirm Coman's finding with pure cultures, to investigate the effects of other carbohydrates and to ascertain whether there was a correlation between the chemotactic effectiveness of carbohydrates and their ability to support growth.…”

Glycoproteins and enzymes associated with the plasmodial membrane and slime layer of Physarum polycephalum.

“…Microplasmodia of Physarum polycephalum were grown under aseptic conditions in a semi-defined medium containing glucose, yeast extract, tryptone and haemin (7). The cultures were shaken in 100 ml of the medium at 26°C in the dark.…”

Characterization of glycopeptides from Physarum polycephalum labeled with (3H)mannose or (3H)glucosamine.

“…The microplasmodia of P. polycephalum were grown under aseptic conditions in a liquid medium containing glucose, yeast extract and tryptone at 26°C with shaking (6). Macrocyst (spherule) formation was induced by transferring the microplasmodia to a medium containing 0.5 M mannitol (differentiation medium) in a dark room (4).…”