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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 ...
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.
E. thermarum as an example of adaptation to extreme environments [2] suggests that the evolution of thermophily in amoebae has occurred across multiple distantly related lineages, indicating that the amoeboid form may be particularly well-suited for high-temperature environments.
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).
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.
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).
An amoeba of the genus Mayorella (Amoebozoa, Discosea). Amoebozoa is a large and diverse group, but certain features are common to many of its members. The amoebozoan cell is typically divided into a granular central mass, called endoplasm, and a clear outer layer, called ectoplasm.
The locomotion of Amoeba proteus exhibits chaotic dynamics described by a low-dimensional chaotic attractor with a correlation dimension around 3-4, indicating that the seemingly random movement arises from deterministic cooperative interactions among a small number of processes like sol-gel transformations, cytoplasmic streaming, and calcium-mediated reactions. [7]