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Current Opinion in Microbiology Dec 2011Protozoan parasites cause tremendous human suffering worldwide, but strategies for therapeutic intervention are limited. Recent studies illustrate that the paradigm of... (Review)
Review
Protozoan parasites cause tremendous human suffering worldwide, but strategies for therapeutic intervention are limited. Recent studies illustrate that the paradigm of microbes as social organisms can be brought to bear on questions about parasite biology, transmission and pathogenesis. This review discusses recent work demonstrating adaptation of social behaviors by parasitic protozoa that cause African sleeping sickness and malaria. The recognition of social behavior and cell-cell communication as a ubiquitous property of bacteria has transformed our view of microbiology, but protozoan parasites have not generally been considered in this context. Works discussed illustrate the potential for concepts of sociomicrobiology to provide insight into parasite biology and should stimulate new approaches for thinking about parasites and parasite-host interactions.
Topics: Cell Communication; Plasmodium; Trypanosoma brucei brucei
PubMed: 22020108
DOI: 10.1016/j.mib.2011.09.012 -
Parasitology Feb 2022Trypanosoma rangeli is a protozoan that infects triatomines and mammals in Latin America, sharing hosts with Trypanosoma cruzi, the etiological agent of Chagas disease....
Trypanosoma rangeli is a protozoan that infects triatomines and mammals in Latin America, sharing hosts with Trypanosoma cruzi, the etiological agent of Chagas disease. Trypanosoma rangeli does not cause disease to humans but is strongly pathogenic to its invertebrate hosts, increasing mortality rates and affecting bug development and reproductive success. We have previously shown that this parasite is also capable of inducing a general increase in the locomotory activity of its vector Rhodnius prolixus in the absence of host cues. In this work, we have evaluated whether infection impacts the insect–vertebrate host interaction. For this, T. rangeli-infected and uninfected R. prolixus nymphs were released in glass arenas offering single shelters. After a 3-day acclimatization, a caged mouse was introduced in each arena and shelter use and predation rates were evaluated. Trypanosoma rangeli infection affected all parameters analysed. A larger number of infected bugs was found outside shelters, both in the absence and presence of a host. Infected bugs also endured greater predation rates, probably because of an increased number of individuals that attempted to feed. Interestingly, mice that predated on infected bugs did not develop T. rangeli infection, suggesting that the oral route is not effective for these parasites, at least in our system. Finally, a smaller number of infected bugs succeeded in feeding in this context. We suggest that, although T. rangeli is not transmitted orally, an increase in the proportion of foraging individuals would promote greater parasite transmission rates through an increased frequency of very effective infected-bug bites.
Topics: Animals; Insect Vectors; Mammals; Mice; Predatory Behavior; Rhodnius; Trypanosoma; Trypanosoma cruzi; Trypanosoma rangeli
PubMed: 35234603
DOI: 10.1017/S0031182021001682 -
Molecular and Biochemical Parasitology Jan 2019Kinetoplastid parasites such as Trypanosoma brucei, Trypanosoma cruzi, and Leishmania species rely upon their insect and vertebrate hosts to provide a plethora of... (Review)
Review
Kinetoplastid parasites such as Trypanosoma brucei, Trypanosoma cruzi, and Leishmania species rely upon their insect and vertebrate hosts to provide a plethora of nutrients throughout their life cycles. Nutrients and ions critical for parasite survival are taken up across the parasite plasma membrane by transporters and channels, polytopic membrane proteins that provide substrate-specific pores across the hydrophobic barrier. However, transporters and channels serve a wide range of biological functions beyond uptake of nutrients. This article highlights the diversity of activities that these integral membrane proteins serve and underscores the emerging complexity of their functions.
Topics: Biological Transport; Leishmania; Membrane Proteins; Membrane Transport Proteins; Protozoan Proteins; Trypanosoma brucei brucei; Trypanosoma cruzi
PubMed: 30590069
DOI: 10.1016/j.molbiopara.2018.12.006 -
Parasitology Aug 2010African trypanosomes have emerged as promising unicellular model organisms for the next generation of systems biology. They offer unique advantages, due to their... (Review)
Review
African trypanosomes have emerged as promising unicellular model organisms for the next generation of systems biology. They offer unique advantages, due to their relative simplicity, the availability of all standard genomics techniques and a long history of quantitative research. Reproducible cultivation methods exist for morphologically and physiologically distinct life-cycle stages. The genome has been sequenced, and microarrays, RNA-interference and high-accuracy metabolomics are available. Furthermore, the availability of extensive kinetic data on all glycolytic enzymes has led to the early development of a complete, experiment-based dynamic model of an important biochemical pathway. Here we describe the achievements of trypanosome systems biology so far and outline the necessary steps towards the ambitious aim of creating a 'Silicon Trypanosome', a comprehensive, experiment-based, multi-scale mathematical model of trypanosome physiology. We expect that, in the long run, the quantitative modelling enabled by the Silicon Trypanosome will play a key role in selecting the most suitable targets for developing new anti-parasite drugs.
Topics: Parasitology; Systems Biology; Trypanosoma
PubMed: 20444304
DOI: 10.1017/S0031182010000466 -
Parasitology Mar 2022The prevalence rates of trypanosomes, including those that require cyclical transmission by tsetse flies, are widely distributed in Africa. Trypanosoma brucei and...
The prevalence rates of trypanosomes, including those that require cyclical transmission by tsetse flies, are widely distributed in Africa. Trypanosoma brucei and Trypanosoma congolense are actively maintained in regions where there are no tsetse flies although at low frequencies. Whether this could be due to an independent evolutionary origin or multiple introduction of trypanosomes due to continuous movement of livestock between tsetse-free and -infested areas is not known. Thus, the aim of the study was to carry out microsatellite genotyping to explore intra-specific genetic diversity between T. (Trypanozoon), T. congolense and Trypanosoma vivax from the two regions: tsetse infested and tsetse free. Microsatellite genotyping showed geographical origin-based structuring among T. (Trypanozoon) isolates. There was a clear separation between isolates from the two regions signalling the potential of microsatellite markers as diagnostic markers for T. brucei and Trypanosoma evansi isolates. Trypanosoma vivax isolates also clustered largely based on the sampling location with a significant differentiation between the two locations. However, our results revealed that T. congolense isolates from Northern Kenya are not genetically separated from those from Coastal Kenya. Therefore, these isolates are likely introduced in the region through animal movement. Our results demonstrate the occurrence of both genetic connectivity as well as independent evolutionary origin, depending on the trypanosome species between the two ecologies.
Topics: Animals; Kenya; Trypanosoma; Trypanosoma brucei brucei; Trypanosoma congolense; Trypanosoma vivax; Trypanosomiasis, African; Tsetse Flies
PubMed: 35264263
DOI: 10.1017/S0031182021001815 -
BioMed Research International 2013This paper reviews the transmission modes of Trypanosoma evansi. Its worldwide distribution is attributed to mechanical transmission. While the role of tabanids is... (Review)
Review
This paper reviews the transmission modes of Trypanosoma evansi. Its worldwide distribution is attributed to mechanical transmission. While the role of tabanids is clear, we raise questions on the relative role of Haematobia sp. and the possible role of Stomoxys sp. in delayed transmission. A review of the available trypanocidal drugs and their efficacy in various host species is useful for understanding how they interact in disease epidemiology, which is complex. Although there are similarities with other mechanically transmitted trypanosomes, T. evansi has a more complex epidemiology due to the diversity of its hosts and vectors. The impact of clinical and subclinical disease is difficult to establish. A model was developed for buffaloes in the Philippines, which could be transferred to other places and livestock systems. Since Trypanosoma evansi was reported in humans, further research is required to investigate its zoonotic potential. Surra remains a potentially emerging disease that is a threat to Australia, Spain, and France. A number of questions about the disease have yet to be resolved. This brief review of the basic knowledge of T. evansi suggests that there is renewed interest in the parasite, which is spreading and has a major economic impact.
Topics: Animals; Buffaloes; Host-Parasite Interactions; Humans; Philippines; Trypanosoma; Trypanosomiasis
PubMed: 24151595
DOI: 10.1155/2013/321237 -
Medecine Et Sante Tropicales 2014Trypanosomes are principally responsible for two human diseases: human African trypanosomiasis (HAT) or sleeping sickness (caused by Trypanosoma brucei gambiense and...
Trypanosomes are principally responsible for two human diseases: human African trypanosomiasis (HAT) or sleeping sickness (caused by Trypanosoma brucei gambiense and T. b. rhodesiense), and Chagas disease, also called South American trypanosomiasis (T. cruzi). However, some trypanosomes that are natural parasites only of animals can sometimes infect humans and cause the so-called "atypical human trypanosomiases" (aHT). T. evansi, the agent causing surra in camels, horses, dogs, and bovines, and T. lewisi, a cosmopolite rat parasite, are the most frequently involved. These atypical infections involve no or only minor symptoms, but major symptoms are sometimes present. Parasite elimination is generally spontaneous, but can require treatment. Molecular tools, such as polymerase chain reaction, have improved the accuracy of parasite identification. Immunological techniques, mainly immunoenzymatic assays, can detect asymptomatic subjects. Several causes, most often concomitant, have been hypothesized, including immune immaturity, immunodeficiency, and close contact with infected animals. Innate immunity to animal trypanosomes depends on a trypanolytic factor called apolipoprotein L-I, present in human serum. A deficit in both apolipoprotein L-I alleles has been reported in an Indian patient infected by T. evansi. The prevalence of aHT is probably underestimated. Moreover, these trypanosomes might become potential emerging zoonotic pathogens, due to their ability to invade new hosts. An international network has been set up to survey these aHT (NAHIAT: Network on Atypical Human Infections by Animal Trypanosomes).
Topics: Animals; Antibodies, Protozoan; DNA, Protozoan; Enzyme-Linked Immunosorbent Assay; Humans; Polymerase Chain Reaction; Trypanosoma; Trypanosomiasis; Zoonoses
PubMed: 24918468
DOI: 10.1684/mst.2014.0346 -
Frontiers in Cellular and Infection... 2021, spp., and are flagellate protozoans of the family Trypanosomatidae and the causative agents of human African trypanosomiasis, leishmaniasis, and Chagas disease,... (Review)
Review
, spp., and are flagellate protozoans of the family Trypanosomatidae and the causative agents of human African trypanosomiasis, leishmaniasis, and Chagas disease, respectively. These diseases affect humans worldwide and exert a significant impact on public health. Over the course of evolution, the parasites associated with these pathologies have developed mechanisms to circumvent the immune response system throughout the infection cycle. In cases of human infection, this function is undertaken by a group of proteins and processes that allow the parasites to propagate and survive during host invasion. In , antigenic variation is promoted by variant surface glycoproteins and other proteins involved in evasion from the humoral immune response, which helps the parasite sustain itself in the extracellular milieu during infection. Conversely, spp. and . possess a more complex infection cycle, with specific intracellular stages. In addition to mechanisms for evading humoral immunity, the pathogens have also developed mechanisms for facilitating their adhesion and incorporation into host cells. In this review, the different immune evasion strategies at cellular and molecular levels developed by these human-pathogenic trypanosomatids have been discussed, with a focus on the key molecules responsible for mediating the invasion and evasion mechanisms and the effects of these molecules on virulence.
Topics: Chagas Disease; Humans; Leishmaniasis; Trypanosoma brucei brucei; Trypanosoma cruzi; Virulence
PubMed: 33937106
DOI: 10.3389/fcimb.2021.669079 -
Parasites & Vectors Feb 2018The trypanosomatid parasites continue their killing spree resulting in significant annual mortality due to the lack of effective treatments and the prominence of these... (Review)
Review
The trypanosomatid parasites continue their killing spree resulting in significant annual mortality due to the lack of effective treatments and the prominence of these diseases in poorer countries. These dimorphic parasites thrive unchecked in the host system, outsmarting the immune mechanisms. An understanding of biology of these parasitic forms will help in the management and elimination of these fatal diseases. Investigation of various metabolic pathways in these parasites has shed light in the understanding of the unique biology of the trypansomatids. An understanding of these pathways have helped in tracing the soft targets in the metabolic pathways, which could be used as effective drug targets which would further impact the therupeutic implications. Pyrimidine pathway is a vital metabolic pathway which yields in the formation of pyrimidines, which are then integrated in nucleic acids (DNA and RNA) in sugars (UDP sugars) and lipids (CDP lipids). A wealth of data and information has been generated in the past decades by in-depth analyses of pyrimidine pathway in the trypanosomatid parasites, which can aid in the identification of anomalies between the parasitic and host counterpart which could be further harnessed to develop therapeutic interventions for the treatment of parasitic diseases. This review presents an updated and comprehensive detailing of the pyrimidine metabolism in the trypansomatids, their uniqueness and their distinctions, and its possible outcomes that would aid in the eradication of these parasitic diseases.
Topics: Biosynthetic Pathways; Carbohydrate Metabolism; DNA; Lipid Metabolism; Pyrimidines; Trypanosoma
PubMed: 29422065
DOI: 10.1186/s13071-018-2660-8 -
Trends in Parasitology Oct 2022Export of RNA from the nucleus is essential for all eukaryotic cells and has emerged as a major step in the control of gene expression. mRNA molecules are required to... (Review)
Review
Export of RNA from the nucleus is essential for all eukaryotic cells and has emerged as a major step in the control of gene expression. mRNA molecules are required to complete a complex series of processing events and pass a quality control system to protect the cytoplasm from the translation of aberrant proteins. Many of these events are highly conserved across eukaryotes, reflecting their ancient origin, but significant deviation from a canonical pathway as described from animals and fungi has emerged in the trypanosomatids. With significant implications for the mechanisms that control gene expression and hence differentiation, responses to altered environments and fitness as a parasite, these deviations may also reveal additional, previously unsuspected, mRNA export pathways.
Topics: Active Transport, Cell Nucleus; Animals; Cell Nucleus; RNA; RNA, Messenger; Trypanosoma
PubMed: 36028415
DOI: 10.1016/j.pt.2022.07.008