Trichamoeba

Page updated 18/1/04

A large monopodal genus whose members have a single, ovular (that is with numerous small nucleoli)  nucleus. This latter feature differentiates Trichamoeba from the otherwise similar Saccamoeba which has a nucleus with a single large nucleolus. Trichamoeba generally have a bulbous uroid from which adhesive filaments (colosomes) may be seen. Although the genus is typically composed of large amoebae, members range from 20 to 325um.   Species have been identified from sea and freshwater. One species (T. sinusa) probably produces a cyst, most do not. As T. villosa cannot be included in the genus (see below), this leaves T. sinusa (Siemensma & Page, 1986) as the only member to be studied by EM (to the best of my knowledge).  The glycocalyx was largely amorphous yet some indications of cylindrical structures, possibly hexagonal in cross-section could be seen. The fine structure of the nucleus was similar to that of Hydramoeba hydroxema.  This is not surprising since Trichamoeba and Hydramoeba are so similar in general form and appearance.  Golgi stacks were visible and the ER present as short tracks.  Floating forms of Trichamoeba is many blunt pseudopods radiating in many directions some granular.

Here are some pictures of a Trichamoeba sp from Lake Ontario kindly supplied by Dr Piotr Rotkiewicz (see Droplet microscopy)

(Each photograph is 130um in width)

Trichamoeba at the Protist Information Server

Trichamoeba cloaca   80-150um in length. Lots of bipyramidal crystals in cytoplasm. Uroid bulbous can have adhesive filaments.(Bovee, 1972)

Trichamoeba gumia  (Schaeffer, 1926) from W.N. Atlantic ocean 60-140um in length.

Trichamoeba hirta The type species of the genus up to 125um in length but is probably not identifiable (Page, 1988).

Trichamoeba limax  up to 100mm. (Jahn & Jahn, 1949).  The status of this species is uncertain as it was only partially described.

Trichamoeba myakka Characterized by having a permanent hyaline often papillate uroid 200-300um in length.

Trichamoeba osseosaccus (Schaeffer, 1926) is 100-150um.

Trichamoeba pallida (Schaeffer, 1926) is 60um in length but sometimes spreads flat on surface.  Isolated from the Gulf of Mexico.

Trichamoeba schaefferi (Radir, 1927)

Trichamoeba sinusa 125-325um in length (making it the largest described Trichamoeba). Many bipyramidal crystals in cytoplasm.  No floating form seen. See above for the description of the E.M. findings (Siemensma & Page, 1986).

Trichamoeba sphaerarum (Schaeffer, 1926) is 20-30um. Isolated from the Gulf of Mexico.

Trichamoeba villosa.   Famous (amongst people who cared about these things at the time) for producing stunning electron micrographs of cortically associated myosin minifilaments supporting the general contraction theory of cell locomotion (Bhowmick, 1967).  Although T. villosa being occasionally polypodal, cannot be considered a member of the Trichamoeba genus, but may be a member of the genus Amoeba instead (Siemensma & Page, 1986; Page, 1988).

Available strains:-

ATCC 50249 Trichamoeba sp. Sawyer, T.K. Virginia Beach VA 1989

References

Bhowmick, D.K. (1967). "Electron microscopy of Trichamoeba villosa and amoeboid movement." Exp.Cell Res. 45: 570-589.

Bovee, E.C. (1951). "Some observations on Trichamoeba osseosaccus (Schaeffer)." Trans.Amer.Microsc.Soc. 70; 47-56.

Bovee, E.C. (1972). "The lobose amoebas IV. A key to the order granulopodida Bovee & Jahn, 1966, and descriptions of some new and little-known species in this order. " Arch.Protistenk. 114: 371-403.

Radir, P.L. (1927). "Trichamoeba schaefferi, a new species of large marine amoeba from Monterey Bay, California." Arch.Protistenk. 59: 289-300.

Siemensma, F.J. & Page, F.C. (1986). "A light and electron-microscopic study of Trichamoeba sinusa N. sp. (amoebida) with are-diagnosis of the genus." Protistologica 22: 117-125.