Defined and Semi-defined Media for the Growth of Amoebae of Physarum polycephalum

Abstract

Amoebae of the true slime mould Physarum polycephalum were cultured in two fully-defined liquid media containing amino acids, glucose, three vitamins and a buffered salts solution. Absolute requirements were demonstrated for methionine, haematin, .thiamine and biotin, all of which were known to be specific requirements of the plasmodial stage. Methods are described for large-scale culture in three semi-defined media.

Chemically defined media for cultivation of Naegleria gruberi

“…The other amebae are Acanthamoeba castellanii (9, 10), Dictyostelium discoidelum (11), Physarum flavicomum (12), and Physasum polycephalum (13). Acanthamoeba and Dictyostelium do not appear to be closely related to each other or to Naegleria, but Physrum may be distantly related to Naegleria (2).…”

“…Hematin, required by Naegleria (8), is also required by both amebae and plasmodia of Physarum (12,13,16) as well as by trypanosomes and diverse other organisms (17). The hematin requirement is a nuisance because it is the only unstable component of the medium; it would be helpful to find a stable substitute.…”

Ultrastructural changes in the myxamoebae of Physarum polycephalum in response to a microcyst-inducing concentration of mannitol

“…Physnruin polycephnluin myxamoebae, strain Cld-Axe, werc cultured axenically in the semidefincd medium described by McCullough and Dee (1976). To induce encystment, stcrile mannitol (9.1 g/ 100 mL) was added directly to cultures either in midlog phase (2 X lo7 cells/mL) or approaching maximum concentration (4 X lo7 cells/ mL), giving a final conccntration of 0.5 M.…”

A Comparison of the Proteins of the Amoebal and Plasanodial Phases of the Slime Mould, Physarum polycephalum

“…This paper compares the proteins of amoebae of strain CL, in which the transition within clones of amoebae has been studied in most detail [l], with the proteins of CL plasmodia, using two-dimensional gel electrophoresis [3]. We had two general objectives: first, to examine differences in gene expression that accompany the transition and second, to identify proteins that change in a sufficiently dramatic manner from one phase to the other to function as markers for analyzing the transition in more detail.Plasmodia may be grown either on complex or on chemically defined media [4,5] but amoebae have only recently been cultured in the absence of live or formalin-killed bacteria [6,7]. However, although it is feasible to grow an axenic strain of amoebae [XI in a medium identical to that which will support growth of a plasmodium, the growth rate and, more importantly, the yield of amoebae in such a medium are both very low, making radioactive labelling experiments uneconomic.…”

“…Plasmodia may be grown either on complex or on chemically defined media [4,5] but amoebae have only recently been cultured in the absence of live or formalin-killed bacteria [6,7]. However, although it is feasible to grow an axenic strain of amoebae [XI in a medium identical to that which will support growth of a plasmodium, the growth rate and, more importantly, the yield of amoebae in such a medium are both very low, making radioactive labelling experiments uneconomic.…”