Prototheca
Genus of algae From Wikipedia, the free encyclopedia
Prototheca is a genus of algae in the family Chlorellaceae.[3] While this genus is a member of the green algae, all Prototheca no longer have chloroplasts and therefore their photosynthetic ability. Some species can cause protothecosis in humans and various vertebrates.
| Prototheca | |
|---|---|
| |
| Prototheca wickerhamii, with Gram stain | |
| Scientific classification | |
| Clade: | Viridiplantae |
| Division: | Chlorophyta |
| Class: | Trebouxiophyceae |
| Order: | Chlorellales |
| Family: | Chlorellaceae |
| Genus: | Prototheca Krüger, 1894[1] |
| Species[2] | |
| |
Etymology
From the Greek proto- (first) + thēkē (sheath), Prototheca is a genus of variably shaped spherical cells of achloric algae in the family Chlorellaceae. Wilhelm Krüger, a German expert in plant physiology and sugar production, reported Prototheca microorganisms in 1894, shortly after spending 7 years in Java studying sugarcane. He isolated Prototheca species from the sap of 3 tree species. Krüger named these organisms as P. moriformis and P. zopfii, the second name as a tribute to Friedrich Wilhelm Zopf, a renowned botanist, mycologist, and lichenologist.[4]
Biology
Prototheca consists of microscopic, single cells, which may sometimes be clustered to form irregular packets. The cell is generally spherical, ellipsoidal or reniform in shape, with a thin and delicate cell wall. Chloroplasts are absent.[5]
With the lack of chloroplasts and photosynthetic ability, Prototheca grow heterotrophically and some exhibit parasitism. Other groups of photosynthetic organisms have undergone similar functional losses in photosynthetic ability and shifted to a parasitic lifestyle, such as in apicomplexans.
Evolution and taxonomy
Although Prototheca lack chloroplasts, they were recognized early on as closely related to other Chlorellaceae based on other morphological and physiological traits similar to the group.[6][7] Phylogenetics confirm that Prototheca species are closely related to Chlorella and other genera, although it is not yet clear whether Prototheca is a monophyletic group.[8]
Pathogenicity
Some species in the genus Prototheca are known to cause protothecosis, one of the few researched diseases caused by algae, which are categorized as Algaemia. P. wickerhamii is the main causing agent of protothecosis in humans, and was first identified as such in 1964. A strain of P. bovis (formerly classified under P. zopfii) is known to cause this disease in cattle, dogs, buffalo, and horses.[9]
Symptoms include: Cutaneous lesions, Olecranon bursitis.
References
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