Patterns of inheritance, development and the mitotic cycle in the protist Physarum polycephalum.

Publisher Summary This chapter summarizes the biology of Physarum polycephalum and gives examples of how the organism has been utilized for analysis of patterns of inheritance, development, and the mitotic cycle. The chapter introduces recent advances in DNA transformation and gene targeting in the organism, and points to definitive experiments now possible using the new technology with the inveterate biology of this plasmodial slime mould. The phases of life cycle of P. polycephalum are amoeba1 phase, plasmodial phase, the sexual cycle, and inheritance. The chapter focuses on genome organization and cytoskeletal organization. The plasmodial mitotic cycle differs from the amoebal cycle in its absence of cytokinesis, and occurrence of mitosis within the nuclear membrane, orchestrated by intranuclear microtubule-organizing centers (MTOCs). This arrangement prevents nuclear fusion during mitosis that occurs in multinucleate amoebae. The molecular analysis in the plasmodium of P. polycephalum can be achieved by introduction of exogenous molecules. The expression of introduced molecules involves diffusion uptake, macroinjection, and DNA transformation. The sophisticated molecular approaches to cell-biological problems are possible in P. polycephalum and in other protists. Further studies will inevitably reveal more knowledge that has been awaiting discovery in these organisms for so many millennia.