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Prototheca bovis, a unicellular achlorophyllous trebouxiophyte green alga in the healthy human intestine

Jinatham, Vasana, Cantoni, Diego, Brown, Ian R., Vichaslip, Thanakrit, Suwannahitatorn, Picha, Popluechai, Siam, Tsaousis, Anastasios D., Gentekaki, Eleni (2021) Prototheca bovis, a unicellular achlorophyllous trebouxiophyte green alga in the healthy human intestine. Journal of Medical Microbiology, 70 (9). Article Number 001415. ISSN 0022-2615. (doi:10.1099/jmm.0.001415) (KAR id:89387)

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Introduction: Prototheca species are non-photosynthetic trebouxiophyte algae ubiquitously distributed in nature and can be found in sewage and soil. This microbial eukaryote causes human protothecosis in immunocompromised individuals. Thus, Prototheca presence in the stool of individuals without gastrointestinal symptoms has been reported only rarely. Hypothesis/Gap statement: There is an absence of detailed characterization of human Prototheca isolates. Aim: The aim of this study was to perform morphological and molecular characterization of Prototheca isolates obtained from human stool. Methodology: Prototheca was isolated from fecal samples of four individuals living in a rural area in Thailand. A combination of bioimaging along with molecular and bioinformatics tools was used to characterize the four strains. The growth rate was tested using four media and three temperature conditions. Phylogenetic analysis using the small subunit ribosomal RNA (SSU rRNA) and cytochrome b (cytb) was also performed. Results: Static and live microscopy demonstrated the various life stages of Prototheca and its major defining cellular characteristics. An optimized DNA extraction methodology that improves DNA yield is provided. Partial fragments of the SSU rRNA and cytb genes were obtained. Phylogenetic analysis placed all four strains in the clade with Prototheca bovis. More broadly, Prototheca was not monophyletic but split into at least two distinct clades instead. Conclusion: The results represent the first molecular characterization of Prototheca in Thailand. The study provides insight into transmission dynamics of the organism and potential caveats in estimating the global prevalence of Prototheca. These will spearhead further investigations on Prototheca occurrence in rural areas of both industrialized and developing nations.

Item Type: Article
DOI/Identification number: 10.1099/jmm.0.001415
Uncontrolled keywords: Gut protists; Imaging; Infection; Phylogeny; Prototheca; Zoonosis
Subjects: Q Science > QR Microbiology
Divisions: Divisions > Division of Natural Sciences > Biosciences
Signature Themes: Migration and Movement
Funders: Biotechnology and Biological Sciences Research Council (
Depositing User: Anastasios Tsaousis
Date Deposited: 20 Jul 2021 19:34 UTC
Last Modified: 25 Nov 2022 12:09 UTC
Resource URI: (The current URI for this page, for reference purposes)
Tsaousis, Anastasios D.:
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