Amoeba

Amoeba (from the Greek. amoibe-edit)- squad Amoebina subclass of corneous (Rhizopoda) class of Arkadevich (Sarcodina) type protozoans (Protozoa). Described several dozen species amoebae (Fig. 1). Body amoeba consists of protoplasm with different organelles and one, two or, less often multiple cores. Protoplasm is divided into two layers: the outer - ectoplasm and internal - endoplasm.

Fig. 1 . Different types of amoebae: 1 - Amoeba proteus; 2 - Naegleria sp.; 3-Amoeba verrucosa; 4 - Entamoeba citelli; 5 - Entamoeba ran arum; 6 - Entamoeba muria.
Fig. 2. Kernel Entamoeba gingivalis at various stages of division (1-4).

Body amoeba constantly changes its shape due to the formation of pseudopodia (logmanager)for movement and for grasping food particles. Form of pseudopodia, different in different species amoebae, nuclear structure, dimensions, etc. are important systematic signs. In some species amoebae the body is covered with a sink (Testacea). The core of amoeba is pozinkovane education, sheathed in which there are pores. Different types of amoebae it is arranged differently. Differences in the structure of the kernel is especially visible on the fixed and stained samples. By building the kernel amoebae can be divided into two types: curiosity and mesh; the first is from free-living amoebae Amoeba C limax vaginal of parasitic - Endolimax nana; kernel amoebae of the second type have a small carisoma, usually located in the downtown core. In the cycle of development amoebae distinguish two phases: vegetative individuals and cysts; the latter is equipped with a shell that protects them from the effects of adverse environmental factors. Reproduction amoebae is carried out by dividing (described amicos and mitosis). Initially divided the core (Fig. 2), then protoplasm. The process of fission of nucleus of different species amoebae is not the same. Vegetative animals feed on bacteria, algae, fungi, grains of starch and other Under adverse conditions the body amoeba covered with a shell - cyst is formed. Many amoebae the core of the cyst is split with the formation of 2, 4, 8 cores or more. In cysts sometimes there are reserves of nutrients (glycogen and others). At hit in favorable conditions cyst burst, and of them overlook amoeba. Then the cycle repeats.
Amoebae are free-living and parasitic way of life. Parasitic amoeba commonly found in the intestinal canal invertebrates and vertebrates. Many owners they do not harm and are usual residents of the digestive tract. This group includes some amoeba that live in the intestines of humans and the oral cavity. It Entamoeba coli, E. gingivalis, Endolimax nana, and other Pathogenic for humans amoeba dysentery - E. histolytica (see Amebiasis).