Protozoa Animal Organisms

A number of extensive reviews on the biochemistry and nutrition of the various groups of Protozoa have been written, some rather recently. Although very few species of this large phylum of animals have been studied biochemically, some interesting information is available for each major subdivision. For only one genus, Tetrahymena, do we have complete information on nutritional requirements, however. 

Relatively few organisms lack the ability to synthesize hematin (certain Trypanosomidae, the blood-sucking redivid Triaioma, and certain bacteria). For these organisms hematin is a true growth factor.  

Not all members of the Trypanosomidae are incapable of synthesizing hematin (Table 1). Strigomonas oncopeltiy S, parva and S. media can be grown in peptone without blood or hematin. In addition to hematin the trypanosomes and the leishmanias require additional factors present in blood.  

The Lwofifs have shown that the activity of hematin is due to its stimulation of respiration (see M. LwofiP) and not to its peroxidase activity. Strigomonas fasciculatay for instance, can insert iron into protoporphyrin and can utilize protohematin. Protoporphyrin appears to be necessary for the synthesis of the respiratory system of aerobic forms, and when organisms lose their ability to carry out its synthesis it must be supplied exogenously if they are to survive. 

Niacin can be synthesized provided that adequate tryptophan is present in the diet. Choline not required when adequate vitamin B12 and methionine present. 

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Single cell protein, normally called simply SCP, is the term used to describe microbial cells, or proteins from them, which are used as food (food for humans) or feed (food for farm animals or fish). Although the term micro-organisms covers viruses, bacteria, fungi, algae and protozoa, viruses and protozoa are not considered suitable for SCP production. 

Recall that the original development of eukaryotic creatures may have started with a symbiotic relationship between two prokaryotes and that symbiosis between algae and nonphotosynthetic organisms may have led to development of higher plants. Associations between species are still important today. For example, the bacteria in the protozoa of the digestive tract of ruminant animals are essential to production of meat. Our own bodies play host to bacteria, fungi,... 

Protozoa are single-celled organisms that represent the lowest division of the animal kingdom. Of the several... 

Ferredoxin is found in representatives of all major groups of organisms except animals (Table 2). It has been found in all photosynthetic bacteria, protozoa (Shapiro (89)), algae, and higher plants which have been exa-... 

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