Prototheca zopfii

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Prototheca zopfii
Histological picture of an infection with Prototheca zopfii in a dog (HE stain)

Histological picture of an infection with Prototheca zopfii in a dog ( HE stain )

Systematics
without rank: Chlorophyta
without rank: Trebouxiophyceae
Order : Chlorellales
Family : Chlorellaceae
Genre : Prototheca
Type : Prototheca zopfii
Scientific name
Prototheca zopfii
W. Kruger

Prototheca zopfii is a ubiquitously occurring green alga , which does not have chlorophyll has. It is widespread in the normal environment and in rare cases can cause a disease called protothecosis in humans and dogs, which usually manifests itself in the form of skin lesions. The species was first described in 1894.

biology

P. zopfii is a unicellular alga, spherical to elliptical in shape and 7 to 30 μm in diameter. The thick-walled cell ( theca ) has a cell wall with two layers that can be distinguished by an electron microscope and contains 2 to 20 non-symmetrically arranged endospores . Reproduction occurs asexually by destroying the mother cell and releasing the spores, which develop into new adult cells. Under ideal conditions, spores are released every 5 to 6 hours. The number of daughter cells is not strictly genetically determined; rather, each cell has a certain probability of producing 2, 4, 8, 16 or 32 daughter cells. This probability does not depend on the number of daughter cells of the previous generation, but can be influenced by changes in the culture medium.

P. zopfii has neither chloroplasts nor chlorophyll. The alga therefore cannot photosynthesize , but lives heterotrophically . It converts 1 mol of glucose to 2 mol of lactic acid . The thermotolerant variety P. zopfii var. Hydrocarbonea can also convert glucose to ethanol and CO 2 under anaerobic conditions at 25 to 40 ° C ( alcoholic fermentation ).

ID

The presence of P. zopfii as a pathogen can be examined for sporangia by culturing infected fluid in Sabouraud dextrose agar or by microscopic examination of tissue samples .

Antimicrobial Therapy

Treatment of infections with P. zopfii is not standardized. Amphotericin B , itraconazole , posaconazole and voriconazole were used.

Individual evidence

  1. ↑ a b Curbelo A & Pankey GA: A man presenting with nodules on hands and elbows . In: Clin Infect Dis . 48, 2009, pp. 1160-1161. doi : 10.1086 / 597466 . PMID 19292636 .
  2. ↑ W. Krüger: Brief description of some lower organisms in the sap flow of deciduous trees . In: Hedwigia , 1894, 33, pp. 241-266
  3. ↑ a b Lass-Flörl C, Mayr A. Human protothecosis. Clin Microbiol Rev. 2007 Apr; 20 (2): 230-42. Review. PMID 17428884
  4. ↑ R. Poyton and D. Branton: Control of daughter-cell number variation in multiple fission: genetic versus environmental determinants in Prototheca . In: PNAS , 1972, 69 pp. 2346-2350
  5. ↑ R. Ueno et al. Isolation, characterization, and fermentative pattern of a novel thermotolerant Prototheca zopfii var. Hydrocarbonea strain Producing ethanol and CO 2 from glucose at 40 ° C . In: Arch. Microbiol. , 2002, 177: pp. 244-250