TY  - JOUR
A1  - Zimmermann, Henriette
A1  - Subota, Ines
A1  - Batram, Christopher
A1  - Kramer, Susanne
A1  - Janzen, Christian J.
A1  - Jones, Nicola G.
A1  - Engstler, Markus
T1  - A quorum sensing-independent path to stumpy development in Trypanosoma brucei
JF  - PLoS Pathogens
N2  - For persistent infections of the mammalian host, African trypanosomes limit their population size by quorum sensing of the parasite-excreted stumpy induction factor (SIF), which induces development to the tsetse-infective stumpy stage. We found that besides this cell density-dependent mechanism, there exists a second path to the stumpy stage that is linked to antigenic variation, the main instrument of parasite virulence. The expression of a second variant surface glycoprotein (VSG) leads to transcriptional attenuation of the VSG expression site (ES) and immediate development to tsetse fly infective stumpy parasites. This path is independent of SIF and solely controlled by the transcriptional status of the ES. In pleomorphic trypanosomes varying degrees of ES-attenuation result in phenotypic plasticity. While full ES-attenuation causes irreversible stumpy development, milder attenuation may open a time window for rescuing an unsuccessful antigenic switch, a scenario that so far has not been considered as important for parasite survival.
KW  - Trypanosoma
KW  - hyperexpression techniques
KW  - parasitic cell cycles
KW  - cloning
KW  - cell cycle and cell division
KW  - cell differentiation
KW  - tetracyclines
KW  - parasitic diseases
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158230
VL  - 13
IS  - 4
ER  - 
TY  - JOUR
A1  - Bargul, Joel L.
A1  - Jung, Jamin
A1  - McOdimba, Francis A.
A1  - Omogo, Collins O.
A1  - Adung'a, Vincent O.
A1  - Krüger, Timothy
A1  - Masiga, Daniel K.
A1  - Engstler, Markus
T1  - Species-Specific Adaptations of Trypanosome Morphology and Motility to the Mammalian Host
JF  - PLoS Pathogens
N2  - African trypanosomes thrive in the bloodstream and tissue spaces of a wide range of mammalian hosts. Infections of cattle cause an enormous socio-economic burden in sub-Saharan Africa. A hallmark of the trypanosome lifestyle is the flagellate’s incessant motion. This work details the cell motility behavior of the four livestock-parasites Trypanosoma vivax, T. brucei, T. evansi and T. congolense. The trypanosomes feature distinct swimming patterns, speeds and flagellar wave frequencies, although the basic mechanism of flagellar propulsion is conserved, as is shown by extended single flagellar beat analyses. Three-dimensional analyses of the trypanosomes expose a high degree of dynamic pleomorphism, typified by the ‘cellular waveform’. This is a product of the flagellar oscillation, the chirality of the flagellum attachment and the stiffness of the trypanosome cell body. The waveforms are characteristic for each trypanosome species and are influenced by changes of the microenvironment, such as differences in viscosity and the presence of confining obstacles. The distinct cellular waveforms may be reflective of the actual anatomical niches the parasites populate within their mammalian host. T. vivax displays waveforms optimally aligned to the topology of the bloodstream, while the two subspecies T. brucei and T. evansi feature distinct cellular waveforms, both additionally adapted to motion in more confined environments such as tissue spaces. T. congolense reveals a small and stiff waveform, which makes these parasites weak swimmers and destined for cell adherence in low flow areas of the circulation. Thus, our experiments show that the differential dissemination and annidation of trypanosomes in their mammalian hosts may depend on the distinct swimming capabilities of the parasites.
KW  - swimming
KW  - viscosity
KW  - flagella
KW  - host-pathogen interactions
KW  - cell motility
KW  - blood
KW  - parasitic diseases
KW  - trypanosoma brucei gambiense
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146513
VL  - 12
IS  - 2
ER  -