Removal of the mRNA 5' cap primes transcripts for degradation and is central for regulating gene expression in eukaryotes. The canonical decapping enzyme Dcp2 is stringently controlled by assembly into a dynamic multi-protein complex together with the 5'-3'exoribonuclease Xrn1. Kinetoplastida lack Dcp2 orthologues but instead rely on the ApaH-like phosphatase ALPH1 for decapping. ALPH1 is composed of a catalytic domain flanked by C- and N-terminal extensions. We show that T. brucei ALPH1 is dimeric in vitro and functions within a complex composed of the trypanosome Xrn1 ortholog XRNA and four proteins unique to Kinetoplastida, including two RNA-binding proteins and a CMGC-family protein kinase. All ALPH1-associated proteins share a unique and dynamic localization to a structure at the posterior pole of the cell, anterior to the microtubule plus ends. XRNA affinity capture in T. cruzi recapitulates this interaction network. The ALPH1 N-terminus is not required for viability in culture, but essential for posterior pole localization. The C-terminus, in contrast, is required for localization to all RNA granule types, as well as for dimerization and interactions with XRNA and the CMGC kinase, suggesting possible regulatory mechanisms. Most significantly, the trypanosome decapping complex has a unique composition, differentiating the process from opisthokonts.
Suramin is one of the oldest drugs in use today. It is still the treatment of choice for the hemolymphatic stage of African sleeping sickness caused by Trypanosoma brucei rhodesiense, and it is also used for surra in camels caused by Trypanosoma evansi. Yet despite one hundred years of use, suramin's mode of action is not fully understood. Suramin is a polypharmacological molecule that inhibits diverse proteins. Here we demonstrate that a DNA helicase of the pontin/ruvB-like 1 family, termed T. brucei RuvBL1, is involved in suramin resistance in African trypanosomes. Bloodstream-form T. b. rhodesiense under long-term selection for suramin resistance acquired a homozygous point mutation, isoleucine-312 to valine, close to the ATP binding site of T. brucei RuvBL1. The introduction of this missense mutation, by reverse genetics, into drug-sensitive trypanosomes significantly decreased their sensitivity to suramin. Intriguingly, the corresponding residue of T. evansi RuvBL1 was found mutated in a suramin-resistant field isolate, in that case to a leucine. RuvBL1 (Tb927.4.1270) is predicted to build a heterohexameric complex with RuvBL2 (Tb927.4.2000). RNAi-mediated silencing of gene expression of either T. brucei RuvBL1 or RuvBL2 caused cell death within 72 h. At 36 h after induction of RNAi, bloodstream-form trypanosomes exhibited a cytokinesis defect resulting in the accumulation of cells with two nuclei and two or more kinetoplasts. Taken together, these data indicate that RuvBL1 DNA helicase is involved in suramin action in African trypanosomes.
- MeSH
- DNA-helikasy genetika MeSH
- suramin farmakologie terapeutické užití MeSH
- Trypanosoma brucei brucei * genetika MeSH
- Trypanosoma brucei rhodesiense genetika MeSH
- Trypanosoma * genetika MeSH
- trypanozomóza africká * farmakoterapie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Camels are considered an important food source in North Africa. Trypanosomiasis in camels is a life-threatening disease that causes severe economic losses in milk and meat production. Therefore, the objective of this study was to determine the trypanosome genotypes in the North African region. Trypanosome infection rates were determined by microscopic examination of blood smears and polymerase chain reaction (PCR). In addition, total antioxidant capacity (TAC), lipid peroxides (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were determined in erythrocyte lysate. Furthermore, 18S amplicon sequencing was used to barcode and characterizes the genetic diversity of trypanosome genotypes in camel blood. In addition to Trypanosoma, Babesia and Thelieria were also detected in the blood samples. PCR showed that the trypanosome infection rate was higher in Algerian samples (25.7%) than in Egyptian samples (7.2%). Parameters such as MDA, GSH, SOD and CAT had significantly increased in camels infected with trypanosomes compared to uninfected control animals, while TAC level was not significantly changed. The results of relative amplicon abundance showed that the range of trypanosome infection was higher in Egypt than in Algeria. Moreover, phylogenetic analysis showed that the Trypanosoma sequences of Egyptian and Algerian camels are related to Trypanosoma evansi. Unexpectedly, diversity within T. evansi was higher in Egyptian camels than in Algerian camels. We present here the first molecular report providing a picture of trypanosomiasis in camels, covering wide geographical areas in Egypt and Algeria.
- MeSH
- antioxidancia MeSH
- fylogeneze MeSH
- genotyp MeSH
- superoxiddismutasa genetika MeSH
- Trypanosoma * genetika MeSH
- trypanozomiáza * epidemiologie veterinární MeSH
- velbloudi MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- severní Afrika MeSH
Recently, based on a limited morphological characterisation and partial 18S rRNA gene sequence, Jiang et al. (2019) described Trypanosoma micropteri Jiang, Lu, Du, Wang, Hu, Su et Li, 2019 as a new pathogen of farmed fish. Here we provide evidence based on the expanded sequence dataset, morphology and experimental infections that this trypanosome does not warrant the establishment as a new species, because it is conspecific with the long-term known Trypanosoma carassii Mitrophanow, 1883, a common haemoflagellate parasite of freshwater fish. The former taxon thus becomes a new junior synonym of T. carassii.
- MeSH
- fylogeneze MeSH
- RNA ribozomální 18S genetika MeSH
- ryby parazitologie MeSH
- sladká voda MeSH
- Trypanosoma * genetika MeSH
- trypanozomiáza * epidemiologie veterinární parazitologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Trypanosoma brucei parasites are the causative agents of African trypanosomiasis in humans, as well as surra, nagana, and dourine in animals. According to current widely used nomenclature, T. brucei is a group of five (sub)species, each causing a distinct disease and possessing unique genetic marker(s) or a combination thereof. However, minimal nuclear genome differences, sometimes accompanied by ongoing genetic exchange, robustly support polyphyly resulting from multiple independent origins of the (sub)species in nature. The ease of generating such (sub)species in the laboratory, as well as the case of overlapping hosts and disease symptoms, is incompatible with the current (sub)species paradigm, which implies a monophyletic origin. Here, we critically re-evaluate this concept, considering recent genome sequencing and experimental studies. We argue that ecotype should be used going forward as a significantly more accurate and appropriate designation.
- MeSH
- lidé MeSH
- Trypanosoma brucei brucei * genetika MeSH
- Trypanosoma * genetika MeSH
- trypanozomiáza * MeSH
- trypanozomóza africká * parazitologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Differentiation is a central aspect of the parasite life cycle and encompasses adaptation to both host and environment. If we accept that evolution cannot anticipate an organism's needs as it enters a new environment, how do parasite differentiation pathways arise? The transition between vertebrate and insect stage African trypanosomes is probably one of the better studied and involves a cell-cycle arrested or 'stumpy' form that activates metabolic pathways advantageous to the parasite in the insect host. However, a range of stimuli and stress conditions can trigger similar changes, leading to formation of stumpy-like cellular states. We propose that the origin and optimisation of this differentiation program represents repurposing of a generic stress response to gain considerable gain-of-fitness associated with parasite transmission.
Transfer RNAs play a key role in protein synthesis. Following transcription, tRNAs are extensively processed prior to their departure from the nucleus to become fully functional during translation. This includes removal of 5′ leaders and 3′ trailers by a specific endo- and/or exonuclease, 3′ CCA tail addition, posttranscriptional modifications and in some cases intron removal. In this minireview, the critical factors of nuclear tRNA trafficking are described based on studies in classical models such as yeast and human cell lines. In addition, recent findings and identification of novel regulatory loops of nuclear tRNA trafficking in trypanosomes are discussed with emphasis on tRNA modifications. The comparison between the representatives of opisthokonts and excavates serves here to understand the evolutionary conservation and diversity of nuclear tRNA export mechanisms.
- MeSH
- buněčné linie MeSH
- lidé MeSH
- RNA jaderná genetika metabolismus MeSH
- RNA transferová genetika metabolismus MeSH
- Saccharomyces cerevisiae genetika metabolismus MeSH
- Trypanosoma genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Horse flies (Diptera: Tabanidae) are of medical and veterinary importance since they transmit a range of pathogens. The horse fly fauna of tropical Africa is still poorly known, and in some geographical areas has not been studied for decades. This study summarizes the results of tabanid collections performed in three West African countries where only sparse data were previously available, the Central African Republic (CAR), Gabon and Liberia. Of 1093 collected specimens, 28 morphospecies and 26 genospecies belonging to six genera were identified, including the first findings of eleven morphospecies in the countries where horse flies were collected: Philoliche (Subpangonia) gravoti Surcouf, 1908 and Tabanus ianthinus Surcouf, 1907 are new records for Liberia; Ancala fasciata f. mixta (Surcouf, 1914), Tabanus fraternus Macquart, 1846, and T. triquetrornatus Carter, 1915 for CAR; Chrysops longicornis Macquart, 1838, Haematopota albihirta Karsch, 1887, H. bowdeni Oldroyd, 1952, and H. brucei Austen, 1908 for Gabon; and Tabanus secedens f. regnaulti Surcouf, 1912 and T. thoracinus Palisot de Beauvois, 1807 for Gabon and Liberia. Species identification of all 28 morphospecies based on morphological features was further supplemented by barcoding of cytochrome oxidase I (COI). Based on the COI sequences of 115 specimens representing 74 haplotypes, a phylogenetic tree was constructed to illustrate the relationships among the tabanid species found and to demonstrate their intra- and interspecific divergences. Our study enriches the current number of barcoded tabanids with another 22 genospecies. Based on the analysis of molecular data we question the taxonomic relevance of the morphological forms Ancala fasciata f. mixta and Tabanus secedens f. regnaulti. A parasitological survey based on nested PCR of 18S rRNA revealed a high (˜25%) prevalence of Trypanosoma theileri in the studied horse flies, accompanied by two species of monoxenous trypanosomatids, Crithidia mellificae and Blastocrithidia sp.
- MeSH
- Diptera klasifikace genetika parazitologie MeSH
- fylogeneze MeSH
- taxonomické DNA čárové kódování MeSH
- Trypanosoma genetika izolace a purifikace MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- západní Afrika MeSH
MRP1/2 is a heteromeric protein complex that functions in the trypanosomatid mitochondrion as part of the RNA editing machinery, which facilitates multiple targeted insertions and deletions of uridines. MRP1/2 was shown to interact with MRB8170, which initiates RNA editing by marking pre-edited mRNAs, while TbRGG2 is required for its efficient progression on pan-edited mRNAs. Both MRP1/2 and TbRGG2 are capable of modulating RNA-RNA interactions in vitro. As determined by using iCLIP and RIP-qPCR, RNAs bound to MRP1/2 are characterized and compared with those associated with MRB8170 and TbRGG2. We provide evidence that MRP1 and MRB8170 have correlated binding and similar RNA crosslinking peak profiles over minimally and never-edited mRNAs. Our results suggest that MRP1 assists MRB8170 in RNA editing on minimally edited mRNAs.
- MeSH
- editace RNA MeSH
- messenger RNA genetika metabolismus MeSH
- mitochondrie genetika metabolismus MeSH
- proteiny vázající RNA metabolismus MeSH
- protozoální proteiny genetika metabolismus MeSH
- RNA mitochondriální genetika metabolismus MeSH
- Trypanosoma genetika metabolismus MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Amphibian trypanosomes were the first ever described trypanosomatids. Nevertheless, their taxonomy remains entangled because of pleomorphism and high prevalence of mixed infections. Despite the fact that the first species in this group were described in Europe, virtually none of the trypanosomes from European anurans was analyzed using modern molecular methods. METHODS: In this study, we explored the diversity and phylogeny of trypanosomes in true frogs from Europe using light microscopy and molecular methods. RESULTS: A comparison of observed morphotypes with previous descriptions allowed us to reliably identify three Trypanosoma spp., whereas the remaining two strains were considered to represent novel taxa. In all cases, more than one morphotype per blood sample was observed, indicating mixed infections. One hundred and thirty obtained 18S rRNA gene sequences were unambiguously subdivided into five groups, correspondent to the previously recognized or novel taxa of anuran trypanosomes. CONCLUSIONS: In this work we studied European frog trypanosomes. Even with a relatively moderate number of isolates, we were able to find not only three well-known species, but also two apparently new ones. We revealed that previous assignments of multiple isolates from distant geographical localities to one species based on superficial resemblance were unjustified. Our work also demonstrated a high prevalence of mixed trypanosome infections in frogs and proposed a plausible scenario of evolution of the genus Trypanosoma.
- MeSH
- druhová specificita MeSH
- fylogeneze * MeSH
- genetická variace MeSH
- klonování DNA MeSH
- polymerázová řetězová reakce MeSH
- RNA protozoální genetika MeSH
- RNA ribozomální 18S genetika MeSH
- Trypanosoma genetika fyziologie MeSH
- žáby krev parazitologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Československo MeSH
- Ukrajina MeSH
