Life cycle[ edit ] Slime mold growing out of a bin of wet paper Slime molds begin life as amoeba -like cells. Retrieved November 14, However, when a chemical signal is secreted, they assemble into a cluster that acts as one organism, which can crawl about to find a suitable location.
They have a similar life style to Dictyostelids. However, even at this level there are conflicts yet to be resolved. The Dictyosteliida are distantly related to the plasmodial slime molds but have the very different life cycle of being cellular slime molds.
A Monograph of the Mycetozoa.
Protozoa and Other Protists. The amoebae and the plasmodia engulf microorganisms. This slug-like organism crawls to an open lit place and grows into a fruiting body. In logs it has the appearance of a slimy webwork of yellow threads, up to a few feet in size.
Behavior[ edit ] When a slime mold mass or mound is physically separated, the cells find their way back to re-unite.
Myxomycetes, commonly overlooked plants. Migration of the plasmodium is accomplished when more protoplasm streams to advancing areas and protoplasm is withdrawn from rear areas.
Some of the amoebae become spores to begin the next generation, but some of the amoebae sacrifice themselves to become a dead stalk, lifting the spores up into the air. These unicellular amoebae are commonly haploidand feed on bacteria. These contain many nuclei without cell membranes between them, and can grow to be meters in size.
The species Fuligo septica is often seen as a slimy yellow network in and on rotting logs. A cellular slime mold involves amoeba-like unicellular protists that spend most of their lives as individuals.
These amoebae can mate if they encounter the correct mating type and form zygotes, which then grow into plasmodia that contain many nuclei without cell membranes between them.
In more strict terms sensu strictoslime molds conform the group of the mycetozoans myxomycetes, dictyostelids, and protostelids.
The mold first densely filled the space with plasmodia, and then thinned the network to focus on efficiently connected branches. Myxogastria or myxomycetes and Protosteli: If one strand is carefully watched for about 50 seconds, the cytoplasm can be seen to slow, stop, and then reverse direction.
As Physarum avoids bright light, light was used to simulate mountains, water and other obstacles in the dish.
Fuligo forms yellow crusts in mulch. Notably, in the case of the cellular slime mold Dictyostelium discoideium, nematodes can consume individual cells, but the multicellular form offers protection from their predation. When the food supply wanes, the Myxomycete plasmodium will enter the next stage of its life cycle forming haploid sporesoften in a well-defined sporangium or other spore-bearing structure.
These sporangia will then release spores which hatch into amoebae to begin the life cycle again. Overcells may aggregate into this multicellular mass, a pseudoplasmodium. These amoebae can mate if they encounter the correct mating type and form zygotes that then grow into plasmodia.
Today, slime molds have been divided between four supergroups and paradoxically none of them is included in the Fungi. Pparasitic protists that belong to the supergroup Rhizaria. In the event that conditions become moist again the sclerotium absorbs water and an active plasmodium is restored.
When the food supply wanes, the plasmodium will migrate to the surface of its substrate and transform into rigid fruiting bodies. The fruiting bodies or sporangia are what we commonly see; they superficially look like fungi or molds but are not related to the true fungi.
Both Acrasiomycota family Acrasidae and Dictyostelida are cellular slime molds, although they are not considered to be closely related. Slime molds can generally be divided into two main groups: They can cause cabbage club root disease and powdery scab tuber disease.
Taxonomy Slime molds as a group sensu lato are polyphyletic. When food runs out and they are ready to form sporangia, they do something radically different than the plasmodial slime molds. About twenty percent of the cells of Dictyostelium discoideium die in the formation of the stalk Kessin et al.Slime mold is the common name for any of the members of a polyphyletic grouping of heterotrophic, fungi-like amoeboid (that is, like an amoeba) organisms that have an alternation of generations life cycle and where at some point separate single-celled protists create a large multicellular or multi-nuclear body.Download