Thiamine-deficiency of Prototheca, a Yeast-like Achloric Alga

Abstract

IN 1894, Krüger¹ described two micro-organisms isolated in Germany from mucous flux of Tilia and Ulmus spp., namely, Prototheca moriformis and P. zopfii. Although the generic diagnosis indicated the micro-organisms to be fungi, they could not be connected with the Saccharomycetes nor with the lower Phycomycetes. Chodat² showed that the genus should be referred to the achloric strains of the alga Chlorella; this was confirmed later on by Printz³. Ashford et al.⁴, isolating P. portoricensis and its variety trispora from cases of human sprue in tropical areas, confirmed the ability of this genus to grow also on chemically defined media, although best growth was always obtained in peptone-containing media. Negroni and Blaisten⁵ reported that it was impossible to cultivate P. ciferrii, isolated from potato skin, in the absence of peptone. More recently, Butler⁶ induced by radiation a number of chlorophyll-less mutants of Chlorella pyrenoidosa that, in his opinion, could be referred to the genus Prototheca. The achloric strains can grow on chemically defined media and do not require vitamins or other growth factors.