Importance of Myxomycetes in Biological Research and Teaching

Myxomycetes, the true slime molds, are highlighted in research and teaching that emphasizes various stages of the life cycle as experimental models. Past and current phylogenetic classifications of Myxomycetes on the tree of life are presented. Life cycle stages are illustrated, described, and discussed. Simple laboratory demonstrations and experiments are described that include spore germination, spore release, and moist chamber cultures utilizing organic matter from various microhabitats. Novel compounds isolated from fruiting bodies and plasmodia of 22 myxomycete species are tabulated, some of which exhibit biological activity that function as antibiotics, antimicrobials, and are cytotoxic to cancer cells. Aeroallergens include myxomycete spores, especially Fuligo septica. The plasmodial stage of Physarum polycephalum has been used as a model research system to study responses to gravity in outer space, solve the shortest pathway through a maze exhibiting " primitive intelligence, " develop a biologically controlled robot, discover what controls synchronous nuclear division , and the development of a new drug Polycefin that shows promise in the treatment of breast and brain cancerous tumors. Life span and senescence experiments showed that aging and longevity were under nuclear control. Environmental ground pollution may be remediated by myxomycete fruiting bodies and plasmodia of Fuligo septica that hyper-accumulate and concentrate highly toxic levels of zinc several thousand fold greater than site vegetation and lesser significant amounts of barium, cadmium, iron, manganese, and strontium. Tree canopy research has shown that aerial pollution results in the decrease of myxomycete species richness at higher elevations for Abies fraseri in Great Smoky Mountains National Park. At lower elevations and locations in the United States of America living Juniperus virginiana tree canopies have the highest species richness (54). Myxomycetes that occur mostly on the bark surface of living trees, shrubs, woody vines, prairie and desert plants fall into five pH groups: low pH (3.5– 4.5), mid-range pH (4.6–6.0) and pH (6.1–7.5), high pH values (7.6–10.0), and a broad spectrum of pH (3.5–7.5). When more environmental parameters are better known myxomycetes may one day serve as the basis for evaluating the impact of pollutants on living trees. Introduction Myxomycetes often are referred to by mushroom hunters as " slime molds " or " slimes " when collected as plasmodia in the field, but are also known as acellular slime molds, plasmodial slime molds or true slime molds (Physarum polycephalum). There are different groups of the so-called " slime molds " that are …