Vahlkampfia

VAHLKAMPFIA (syn.-Amoeba Umax), small amoebas with characteristic rolling movement, forming mostly elongated, finger-like pseudopodia. The nucleus contains a large karyosome, which during division is drawn out and distributed between the daughter nuclei; while the chromosomes arise from the outer part of the nucleus (figures-see vol. I, p. 521, fig. 11 a-e). They do not have flagellated stages. They form uninucleate cysts. Free-living V. have a contractile vacuole. V. are extremely widespread in nature. They occur as saprophytes in decaying plant infusions. When entering the intestines of various animals, V. cysts can pass through unchanged and only germinate after being excreted from the body. This source of appearance of mobile amoebas in intestinal material, i.e., with the germination of cysts that only pass through the intestine but do not develop in it, must be taken into account when evaluating the results of corresponding studies. Some V. have adapted to varying degrees to a parasitic mode of life, with some, developing in the lower parts of the intestine, possibly not having lost the ability to exist outside the body; these are so-called semi-parasites, or facultative parasites. Others have perhaps finally adapted to parasitic existence. Pathogenic forms are unknown.- Example: V. limax Duj., 1841, small saprophytic amoebas, found in decaying hay infusions, as well as on artificial media-in cultures of human and various animal intestinal secretions.