Prototheca

Prototheca is a genus of algae in the family Chlorellaceae. While taxonomy classifies this genus as member of the green algae, all species in this genus have lost their chloroplasts and thus forfeited their photosynthetic ability. Some species can cause protothecosis in humans and various vertebratae.

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.

Biology
With the lack of chloroplasts and photosynthetic ability, Prototheca species resort to heterotrophic growth and exhibit parasitism.

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. P. zopfii is known to cause this disease in cattle and dogs.

Symptoms include: Cutaneous lesions, Olecranon bursitis.