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Life cycle. Dictyostelium discoideum is a species of soil-dwelling amoeba belonging to the phylum Amoebozoa, infraphylum Mycetozoa.Commonly referred to as slime mold, D. discoideum is a eukaryote that transitions from a collection of unicellular amoebae into a multicellular slug and then into a fruiting body within its lifetime.
They exist as single-celled organisms while food is plentiful. When food is in short supply, many of the single-celled amoebae congregate and start moving as a single body, called a 'slug'. The ability of the single celled organisms to aggregate into multicellular forms are why they are also called the social amoebae.
Most of its life, this haploid social amoeba undergoes a vegetative cycle, preying upon bacteria in the soil, and periodically dividing mitotically. When food is scarce, either the sexual cycle or the social cycle begins. Under the social cycle, amoebae aggregate in response to cAMP by the thousands, and form a motile slug, which moves towards ...
A petri dish of Dictyostelium.. When food (normally bacteria) is readily available dictyostelids behave as individual amoebae, which feed and divide normally. However, when the food supply is exhausted, they aggregate to form a multicellular assembly, called a pseudoplasmodium, grex, or slug (not to be confused with the gastropod mollusc called a slug).
Clockwise from top right: Amoeba proteus, Actinophrys sol, Acanthamoeba sp., Nuclearia thermophila., Euglypha acanthophora, neutrophil ingesting bacteria. An amoeba (/ ə ˈ m iː b ə /; less commonly spelled ameba or amœba; pl.: amoebas (less commonly, amebas) or amoebae (amebae) / ə ˈ m iː b i /), [1] often called an amoeboid, is a type of cell or unicellular organism with the ability ...
When starving, the usually solitary single-celled amoebae aggregate and form a multicellullar slug that can contain 10 4 –10 6 cells. This slug migrates to the soil surface, where it transforms into a fruiting body composed of a spherical tip of spores and a stalk consisting of nonviable stalk cells that hold the spores aloft (Figure 2).
As the life cycle diagram indicates, amoebae and plasmodia differ markedly in their developmental potential. A remarkable further difference is the mechanism of mitosis. Amoebae exhibit “open mitosis” during which the nuclear membrane breaks down, as is typical of animal cells, before reassembling after telophase. Plasmodia exhibit ...
Acrasis rosea amoebae and spores under microscope. The family Acrasidae (ICZN, or Acrasiomycota, ICBN) is a family [1] of slime molds which belongs to the excavate group Percolozoa. The name element acrasio - comes from the Greek akrasia, meaning "acting against one's judgement". This group consists of cellular slime molds.