The identification of these amoebae are based on their size, the shape and number of pseudopodia, appearance of the cytoplasm, number of nuclei, among other characters.
Naked amoeba with multiple pseudopodia, shaped as small conical projections of cytoplasm, rather than tubular or lobose. Here the cell seems to be sending out sheets of hyaline cytoplasm in the direction of motion.
A large amoeba with multiple tubular pseudopodia, often pointing in different directions, but melded at the base, radiating outward like spokes.
This series of images shows the changing shapes of a single amoeba. New outgrowths begin as small spherical blebs that swell and sprout blebs of their own, resulting in a chain of bubble-shaped bulges. Here it has grown outwards in three directions. The accompanying video illustrates the speed of cytoplasmic streaming and remolding.[vimeo http://vimeo.com/26915500]
Amoebae with a single pseudopodium. Some unidentified species below.
Small amoeba with a single rounded and hyaline pseudopodium shaped like a fan (left). Trailing behind is a bundle of cytoplasm and assorted granules (arrow).
Small monopodial amoeba with a hyaline “cap” on its single pseudopodium, and no obvious uroid (tail) structures.
Small monopodial amoeba without a hyaline “cap” on its pseudopodium; its uroid has small finger-like projections.
Amoeba ejecting waste
Protists need to poop too. Watch a vacuole of waste material (inorganic grains?) get deposited outside the cell.
Not a true species, “Amoeba radiosa” refers to the radiating pseudopod arms of a swimming amoeba, very different from the flattened appearance of the typical textbook amoeba that is adhered to a microscope slide. When it has anchored itself it may look quite different! This series demonstrates the changes as a floating amoeba begins to anchor to the microscope slide.
Response to light
This cell, which may be an Amoeba, moves by extending one or two pseudopodia forward. The pseudopodia have a hyaline cap. However when it is illuminated by the light beam of the microscope, I observed that the hyaline zone “breaks out” along the entire border of the cell, and the former directional movement is lost. The prominent circular structure in the cell is a contractile vacuole.
This individual may be a Mayorella, because of the pointed pseudopodial protrusions on the leading edge of the cell.
Colichopodium (testate amoebae)