scholarly journals Evolutionary diversification of the trypanosome haptoglobin-haemoglobin receptor from an ancestral haemoglobin receptor

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Harriet Lane-Serff ◽  
Paula MacGregor ◽  
Lori Peacock ◽  
Olivia JS Macleod ◽  
Christopher Kay ◽  
...  
Keyword(s):  
Developmental Stage ◽  
Trypanosoma Brucei ◽  
Evolutionary History ◽  
Trypanosoma Congolense ◽  
Tsetse Fly ◽  
Mammalian Host ◽  
Trypanosome Species ◽  
African Trypanosome ◽  
Evolutionary Diversification ◽  
Cellular Changes

The haptoglobin-haemoglobin receptor of the African trypanosome species, Trypanosoma brucei, is expressed when the parasite is in the bloodstream of the mammalian host, allowing it to acquire haem through the uptake of haptoglobin-haemoglobin complexes. Here we show that in Trypanosoma congolense this receptor is instead expressed in the epimastigote developmental stage that occurs in the tsetse fly, where it acts as a haemoglobin receptor. We also present the structure of the T. congolense receptor in complex with haemoglobin. This allows us to propose an evolutionary history for this receptor, charting the structural and cellular changes that took place as it adapted from a role in the insect to a new role in the mammalian host.

scholarly journals Surface Sialic Acids Taken from the Host Allow Trypanosome Survival in Tsetse Fly Vectors

2004 ◽  
Vol 199 (10) ◽  
pp. 1445-1450 ◽  
Author(s):  
Kisaburo Nagamune ◽  
Alvaro Acosta-Serrano ◽  
Haruki Uemura ◽  
Reto Brun ◽  
Christina Kunz-Renggli ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Trypanosoma Brucei ◽  
Sialic Acids ◽  
Sleeping Sickness ◽  
Tsetse Fly ◽  
Mammalian Host ◽  
Tsetse Flies ◽  
African Trypanosome ◽  
Blood Sucking

The African trypanosome Trypanosoma brucei, which causes sleeping sickness in humans and Nagana disease in livestock, is spread via blood-sucking Tsetse flies. In the fly's intestine, the trypanosomes survive digestive and trypanocidal environments, proliferate, and translocate into the salivary gland, where they become infectious to the next mammalian host. Here, we show that for successful survival in Tsetse flies, the trypanosomes use trans-sialidase to transfer sialic acids that they cannot synthesize from host's glycoconjugates to the glycosylphosphatidylinositols (GPIs), which are abundantly expressed on their surface. Trypanosomes lacking sialic acids due to a defective generation of GPI-anchored trans-sialidase could not survive in the intestine, but regained the ability to survive when sialylated by means of soluble trans-sialidase. Thus, surface sialic acids appear to protect the parasites from the digestive and trypanocidal environments in the midgut of Tsetse flies.

scholarly journals Metabolic reprogramming during the Trypanosoma brucei life cycle

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 683 ◽  
Author(s):  
Terry K. Smith ◽  
Frédéric Bringaud ◽  
Derek P. Nolan ◽  
Luisa M. Figueiredo
Keyword(s):  
Life Cycle ◽  
Trypanosoma Brucei ◽  
Model Organism ◽  
Protozoan Parasite ◽  
Tsetse Fly ◽  
Metabolic Reprogramming ◽  
Mammalian Host ◽  
Insect Vector ◽  
Environmental Signals ◽  
Cellular Metabolic Activity

Cellular metabolic activity is a highly complex, dynamic, regulated process that is influenced by numerous factors, including extracellular environmental signals, nutrient availability and the physiological and developmental status of the cell. The causative agent of sleeping sickness, Trypanosoma brucei, is an exclusively extracellular protozoan parasite that encounters very different extracellular environments during its life cycle within the mammalian host and tsetse fly insect vector. In order to meet these challenges, there are significant alterations in the major energetic and metabolic pathways of these highly adaptable parasites. This review highlights some of these metabolic changes in this early divergent eukaryotic model organism.

scholarly journals Differential virulence and tsetse fly transmissibility of Trypanosoma congolense and Trypanosoma brucei strains

2017 ◽  
Vol 84 (1) ◽  
Author(s):  
Purity K. Gitonga ◽  
Kariuki Ndung’u ◽  
Grace A. Murilla ◽  
Paul C. Thande ◽  
Florence N. Wamwiri ◽  
...  
Keyword(s):  
Survival Time ◽  
Trypanosoma Brucei ◽  
Acute Infection ◽  
Glossina Pallidipes ◽  
Trypanosoma Congolense ◽  
Tsetse Fly ◽  
Economic Losses ◽  
Entire Group ◽  
Tsetse Flies ◽  
African Countries

African animal trypanosomiasis causes significant economic losses in sub-Saharan African countries because of livestock mortalities and reduced productivity. Trypanosomes, the causative agents, are transmitted by tsetse flies (Glossina spp.). In the current study, we compared and contrasted the virulence characteristics of five Trypanosoma congolense and Trypanosoma brucei isolates using groups of Swiss white mice (n = 6). We further determined the vectorial capacity of Glossina pallidipes, for each of the trypanosome isolates. Results showed that the overall pre-patent (PP) periods were 8.4 ± 0.9 (range, 4–11) and 4.5 ± 0.2 (range, 4–6) for T. congolense and T. brucei isolates, respectively (p < 0.01). Despite the longer mean PP, T. congolense–infected mice exhibited a significantly (p < 0.05) shorter survival time than T. brucei–infected mice, indicating greater virulence. Differences were also noted among the individual isolates with T. congolense KETRI 2909 causing the most acute infection of the entire group with a mean ± standard error survival time of 9 ± 2.1 days. Survival time of infected tsetse flies and the proportion with mature infections at 30 days post-exposure to the infective blood meals varied among isolates, with subacute infection–causing T. congolense EATRO 1829 and chronic infection–causing T. brucei EATRO 2267 isolates showing the highest mature infection rates of 38.5% and 23.1%, respectively. Therefore, our study provides further evidence of occurrence of differences in virulence and transmissibility of eastern African trypanosome strains and has identified two, T. congolense EATRO 1829 and T. brucei EATRO 2267, as suitable for tsetse infectivity and transmissibility experiments.

scholarly journals Prevalence of Cattle Trypanosomosis and Apparent Density of Its Fly Vectors in Bambasi District of Benishangul-Gumuz Regional State, Western Ethiopia

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Morka Amante ◽  
Hika Tesgera
Keyword(s):  
Trypanosoma Brucei ◽  
Body Condition ◽  
Apparent Density ◽  
Tsetse Fly ◽  
Meat Production ◽  
Tsetse Flies ◽  
Trypanosoma Vivax ◽  
Trypanosome Species ◽  
Cross Sectional ◽  
Significant Difference

Trypanosomosis is the most serious disease of cattle, which causes great socioeconomic losses in the country. Its socioeconomic impact is reflected on direct losses due to mortality, morbidity, and reduction in milk and meat production, abortion and stillbirth, and also costs associated with combat of the disease are direct losses. A cross-sectional study was carried out to assess the prevalence of cattle trypanosomosis, and the apparent density and distribution of its fly vectors in selected study areas. The methods employed during the study were buffy coat technique for parasitological study and deploying trap for the collection of tsetse flies. A total of 1512 flies were trapped, and among them, 1162 were tsetse flies while 350 were biting flies. Higher apparent density for tsetse fly (7.7 F/T/D) followed by Stomoxys (0.9 F/T/D), Tabanus (0.8 F/T/D), and Hematopota (0.6 F/T/D) was recorded. Out of 638 examined cattle, the overall prevalence of trypanosomosis in the study area was 9.1% (58/638). Out of positive cases, Trypanosoma congolense (7.7%) was the dominant trypanosome species followed by Trypanosoma vivax (0.9%), Trypanosoma brucei (0.2%), and mixed infection of Trypanosoma brucei and Trypanosoma vivax (0.3%). There was no a significant difference (p>0.05) in trypanosome infection between age, sex, and trypanosome species. The prevalence of trypanosomosis on the bases of body condition was 2.8% for poor, 5.5% for medium, and 0.8% for good body condition. The overall prevalence of anemia was (36.8%), and presence of anemia was higher in trypanosome positive animals (62.5%) than in negative animals (34.3%) which is statistically significant (p<0.05, CI = 1.794–5.471). The overall mean packed cell volume (PCV) value for examined animals was 25.84 ± 0.252SE. Mean (PCV) of parasitaemic cattle (9.1%) was significantly (p<0.05) lower than that of aparasitaemic cattle (90%). This survey showed that trypanosomosis is still a core problem for livestock production of the study area. Therefore, more attention should be given to the control of both the disease and its vectors.

Trypanosome Signaling—Quorum Sensing

2021 ◽  
Vol 75 (1) ◽  
Author(s):  
Keith R. Matthews
Keyword(s):  
Quorum Sensing ◽  
Historical Context ◽  
Tsetse Fly ◽  
Sub Saharan Africa ◽  
Mammalian Host ◽  
Annual Review ◽  
Publication Date ◽  
Trypanosome Species ◽  
African Trypanosomes ◽  
Infection Dynamics

African trypanosomes are responsible for important diseases of humans and animals in sub-Saharan Africa. The best-studied species is Trypanosoma brucei, which is characterized by development in the mammalian host between morphologically slender and stumpy forms. The latter are adapted for transmission by the parasite's vector, the tsetse fly. The development of stumpy forms is driven by density-dependent quorum-sensing (QS), the molecular basis for which is now coming to light. In this review, I discuss the historical context and biological features of trypanosome QS and how it contributes to the parasite's infection dynamics within its mammalian host. Also, I discuss how QS can be lost in different trypanosome species, such as T. brucei evansi and T. brucei equiperdum, or modulated when parasites find themselves competing with others of different genotypes or of different trypanosome species in the same host. Finally, I consider the potential to exploit trypanosome QS therapeutically. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Protein tyrosine phosphatase TbPTP1: a molecular switch controlling life cycle differentiation in trypanosomes

2006 ◽  
Vol 175 (2) ◽  
pp. 293-303 ◽  
Author(s):  
Balázs Szöőr ◽  
Jude Wilson ◽  
Helen McElhinney ◽  
Lydia Tabernero ◽  
Keith R. Matthews
Keyword(s):  
Life Cycle ◽  
Trypanosoma Brucei ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Tsetse Fly ◽  
Mammalian Host ◽  
African Trypanosomes ◽  
Protein Tyrosine ◽  
Ptp1b Inhibitors ◽  
Stumpy Form

Differentiation in African trypanosomes (Trypanosoma brucei) entails passage between a mammalian host, where parasites exist as a proliferative slender form or a G0-arrested stumpy form, and the tsetse fly. Stumpy forms arise at the peak of each parasitaemia and are committed to differentiation to procyclic forms that inhabit the tsetse midgut. We have identified a protein tyrosine phosphatase (TbPTP1) that inhibits trypanosome differentiation. Consistent with a tyrosine phosphatase, recombinant TbPTP1 exhibits the anticipated substrate and inhibitor profile, and its activity is impaired by reversible oxidation. TbPTP1 inactivation in monomorphic bloodstream trypanosomes by RNA interference or pharmacological inhibition triggers spontaneous differentiation to procyclic forms in a subset of committed cells. Consistent with this observation, homogeneous populations of stumpy forms synchronously differentiate to procyclic forms when tyrosine phosphatase activity is inhibited. Our data invoke a new model for trypanosome development in which differentiation to procyclic forms is prevented in the bloodstream by tyrosine dephosphorylation. It may be possible to use PTP1B inhibitors to block trypanosomatid transmission.

Neutralization of individual variable antigen types in metacyclic populations of Trypanosoma brucei does not prevent their subsequent expression in mice

Parasitology ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 79-88 ◽  
Author(s):  
J. D. Barry ◽  
J. S. Crowe ◽  
K. Vickerman
Keyword(s):  
Salivary Glands ◽  
Trypanosoma Brucei ◽  
Bloodstream Infections ◽  
Visual Observation ◽  
Tsetse Fly ◽  
Mammalian Host ◽  
Characteristic Set ◽  
Specific Antibodies ◽  
Antigenic Composition ◽  
Variable Antigen

The Trypanosoma brucei metacyclic population in the salivary glands of the tsetse fly displays a characteristic set of variable antigen types (VATs) which represents only a restricted part of the parasite's total VAT repertoire. After introduction into the mammalian host by fly bite, the metacyclics transform into bloodstream forms which retain expression of the metacyclic VATs. Specific antibodies, both polyvalent and monoclonal, have been used to neutralize separately 4 individual VATs from metacyclic populations. Control experiments and visual observation confirmed lysis of each VAT. On injection of the surviving trypanosomes, after washing, into mice each neutralized VAT was nevertheless expressed within a few days. Simultaneous neutralization of 2 metacyclic VATs which usually switch to one another in bloodstream infections did not prevent expression of either on subsequent injection into mice. Expression of neutralized VATs was not influenced by the antigenic composition of the population originally ingested by the tsetse fly. Metacyclic forms and their immediate successors thus appear to switch rapidly to expression of other metacyclic VATs in bloodstream populations.

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