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Social motility of African trypanosomes is a property of a distinct life-cycle stage that occurs early in tsetse fly transmission.

Imhof S, Knüsel S, Gunasekera K, Vu XL, Roditi I - PLoS Pathog. (2014)

Bottom Line: These findings link the phenomenon of SoMo in vitro to the parasite forms found during the first 4-7 days of a midgut infection.Moreover, the process can be uncoupled from colonisation of the salivary glands.Although they are the major surface proteins of procyclic forms, EP and GPEET are not essential for SoMo, nor, as shown previously, are they required for near normal colonisation of the fly midgut.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cell Biology, University of Bern, Bern, Switzerland; Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.

ABSTRACT
The protozoan pathogen Trypanosoma brucei is transmitted between mammals by tsetse flies. The first compartment colonised by trypanosomes after a blood meal is the fly midgut lumen. Trypanosomes present in the lumen-designated as early procyclic forms-express the stage-specific surface glycoproteins EP and GPEET procyclin. When the trypanosomes establish a mature infection and colonise the ectoperitrophic space, GPEET is down-regulated, and EP becomes the major surface protein of late procyclic forms. A few years ago, it was discovered that procyclic form trypanosomes exhibit social motility (SoMo) when inoculated on a semi-solid surface. We demonstrate that SoMo is a feature of early procyclic forms, and that late procyclic forms are invariably SoMo-negative. In addition, we show that, apart from GPEET, other markers are differentially expressed in these two life-cycle stages, both in culture and in tsetse flies, indicating that they have different biological properties and should be considered distinct stages of the life cycle. Differentially expressed genes include two closely related adenylate cyclases, both hexokinases and calflagins. These findings link the phenomenon of SoMo in vitro to the parasite forms found during the first 4-7 days of a midgut infection. We postulate that ordered group movement on plates reflects the migration of parasites from the midgut lumen into the ectoperitrophic space within the tsetse fly. Moreover, the process can be uncoupled from colonisation of the salivary glands. Although they are the major surface proteins of procyclic forms, EP and GPEET are not essential for SoMo, nor, as shown previously, are they required for near normal colonisation of the fly midgut.

No MeSH data available.


Related in: MedlinePlus

GPEET is not essential for SoMo.(A) 2×105 ΔGPEET cells, cultured with or without glycerol, were inoculated onto a plate containing 20 mM glycerol. Four days post plating only the cells cultured in medium containing glycerol showed SoMo. The scale bar is 1 cm. (B) 4×105 ΔGPEET/GFP cells, cultured in medium containing glycerol, were inoculated onto a plate containing 20 mM glycerol. Four days post plating a community lift was stained with α-GFP antibody.
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ppat-1004493-g003: GPEET is not essential for SoMo.(A) 2×105 ΔGPEET cells, cultured with or without glycerol, were inoculated onto a plate containing 20 mM glycerol. Four days post plating only the cells cultured in medium containing glycerol showed SoMo. The scale bar is 1 cm. (B) 4×105 ΔGPEET/GFP cells, cultured in medium containing glycerol, were inoculated onto a plate containing 20 mM glycerol. Four days post plating a community lift was stained with α-GFP antibody.

Mentions: GPEET is the major surface protein of early procyclic forms. To test if it was required for SoMo we used the ΔGPEET deletion mutant previously generated in our laboratory [6]. Since these cells lack a marker for early procyclic forms, we once again took bloodstream forms and triggered them to differentiate to procyclic forms. In common with its wild-type parent, ΔGPEET was SoMo-positive as long as it was cultured in the presence of glycerol and became SoMo-negative after being transferred to glycerol-free medium (Figure 3A). In order to track the differentiation status of ΔGPEET, it was transformed with a reporter construct in which the GFP coding region is fused to the GPEET 3′ untranslated region [23]. This regulatory sequence ensures that expression of GFP mimics that of GPEET, and indicates whether or not a cell is still an early procyclic form. A community lift using an anti-GFP antibody revealed once again that only the early procyclic forms migrate while the late, GFP-negative cells stay at the point of inoculation (Figure 3B). In addition to migrating, ΔGPEET cells are still capable of recognising and reacting to other trypanosome communities (Figure 3A).


Social motility of African trypanosomes is a property of a distinct life-cycle stage that occurs early in tsetse fly transmission.

Imhof S, Knüsel S, Gunasekera K, Vu XL, Roditi I - PLoS Pathog. (2014)

GPEET is not essential for SoMo.(A) 2×105 ΔGPEET cells, cultured with or without glycerol, were inoculated onto a plate containing 20 mM glycerol. Four days post plating only the cells cultured in medium containing glycerol showed SoMo. The scale bar is 1 cm. (B) 4×105 ΔGPEET/GFP cells, cultured in medium containing glycerol, were inoculated onto a plate containing 20 mM glycerol. Four days post plating a community lift was stained with α-GFP antibody.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4214818&req=5

ppat-1004493-g003: GPEET is not essential for SoMo.(A) 2×105 ΔGPEET cells, cultured with or without glycerol, were inoculated onto a plate containing 20 mM glycerol. Four days post plating only the cells cultured in medium containing glycerol showed SoMo. The scale bar is 1 cm. (B) 4×105 ΔGPEET/GFP cells, cultured in medium containing glycerol, were inoculated onto a plate containing 20 mM glycerol. Four days post plating a community lift was stained with α-GFP antibody.
Mentions: GPEET is the major surface protein of early procyclic forms. To test if it was required for SoMo we used the ΔGPEET deletion mutant previously generated in our laboratory [6]. Since these cells lack a marker for early procyclic forms, we once again took bloodstream forms and triggered them to differentiate to procyclic forms. In common with its wild-type parent, ΔGPEET was SoMo-positive as long as it was cultured in the presence of glycerol and became SoMo-negative after being transferred to glycerol-free medium (Figure 3A). In order to track the differentiation status of ΔGPEET, it was transformed with a reporter construct in which the GFP coding region is fused to the GPEET 3′ untranslated region [23]. This regulatory sequence ensures that expression of GFP mimics that of GPEET, and indicates whether or not a cell is still an early procyclic form. A community lift using an anti-GFP antibody revealed once again that only the early procyclic forms migrate while the late, GFP-negative cells stay at the point of inoculation (Figure 3B). In addition to migrating, ΔGPEET cells are still capable of recognising and reacting to other trypanosome communities (Figure 3A).

Bottom Line: These findings link the phenomenon of SoMo in vitro to the parasite forms found during the first 4-7 days of a midgut infection.Moreover, the process can be uncoupled from colonisation of the salivary glands.Although they are the major surface proteins of procyclic forms, EP and GPEET are not essential for SoMo, nor, as shown previously, are they required for near normal colonisation of the fly midgut.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cell Biology, University of Bern, Bern, Switzerland; Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.

ABSTRACT
The protozoan pathogen Trypanosoma brucei is transmitted between mammals by tsetse flies. The first compartment colonised by trypanosomes after a blood meal is the fly midgut lumen. Trypanosomes present in the lumen-designated as early procyclic forms-express the stage-specific surface glycoproteins EP and GPEET procyclin. When the trypanosomes establish a mature infection and colonise the ectoperitrophic space, GPEET is down-regulated, and EP becomes the major surface protein of late procyclic forms. A few years ago, it was discovered that procyclic form trypanosomes exhibit social motility (SoMo) when inoculated on a semi-solid surface. We demonstrate that SoMo is a feature of early procyclic forms, and that late procyclic forms are invariably SoMo-negative. In addition, we show that, apart from GPEET, other markers are differentially expressed in these two life-cycle stages, both in culture and in tsetse flies, indicating that they have different biological properties and should be considered distinct stages of the life cycle. Differentially expressed genes include two closely related adenylate cyclases, both hexokinases and calflagins. These findings link the phenomenon of SoMo in vitro to the parasite forms found during the first 4-7 days of a midgut infection. We postulate that ordered group movement on plates reflects the migration of parasites from the midgut lumen into the ectoperitrophic space within the tsetse fly. Moreover, the process can be uncoupled from colonisation of the salivary glands. Although they are the major surface proteins of procyclic forms, EP and GPEET are not essential for SoMo, nor, as shown previously, are they required for near normal colonisation of the fly midgut.

No MeSH data available.


Related in: MedlinePlus