Tubulin and microtubules (MTs) are potential protein targets to treat parasitic infections and our previous studies have shown that the triazolopyrimidine (TPD) class of MT-active compounds hold promise as antitrypanosomal agents. MT-targeting TPDs include structurally related but functionally diverse congeners that interact with mammalian tubulin at either one or two distinct interfacial binding sites; namely, the seventh and vinca sites, which are found within or between α,β-tubulin heterodimers, respectively. Evaluation of the activity of 123 TPD congeners against cultured Trypanosoma brucei enabled a robust quantitative structure-activity relationship (QSAR) model and the prioritization of two congeners for in vivo pharmacokinetics (PK), tolerability and efficacy studies. Treatment of T. brucei-infected mice with tolerable doses of TPDs significantly decreased blood parasitemia within 24 h. Further, two once-weekly doses at 10 mg/kg of a candidate TPD significantly extended the survival of infected mice relative to infected animals treated with vehicle. Further optimization of dosing and/or the dosing schedule of these CNS-active TPDs may provide alternative treatments for human African trypanosomiasis.

• Klíčová slova
• Triazolopyrimidines, Trypanosoma brucei, drug discovery, human African trypanosomiasis, microtubules,
• MeSH
• lidé MeSH
• mikrotubuly metabolismus   MeSH
• myši MeSH
• pyrimidiny farmakologie   terapeutické užití   chemie   MeSH
• savci metabolismus   MeSH
• trypanocidální látky * farmakologie   terapeutické užití   chemie   MeSH
• Trypanosoma brucei brucei * metabolismus   MeSH
• trypanozomóza africká * farmakoterapie   MeSH
• tubulin metabolismus   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• pyrimidiny MeSH
• trypanocidální látky * MeSH
• tubulin 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.

• Klíčová slova
• Trypanosoma, diversity, evolution, parasitism, population structure, speciation,
• 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
• práce podpořená grantem MeSH
• přehledy MeSH

In the bloodstream of mammalian hosts, African trypanosomes face the challenge of protecting their invariant surface receptors from immune detection. This crucial role is fulfilled by a dense, glycosylated protein layer composed of variant surface glycoproteins (VSGs), which undergo antigenic variation and provide a physical barrier that shields the underlying invariant surface glycoproteins (ISGs). The protective shield's limited permeability comes at the cost of restricted access to the extracellular host environment, raising questions regarding the specific function of the ISG repertoire. In this study, we employ an integrative structural biology approach to show that intrinsically disordered membrane-proximal regions are a common feature of members of the ISG super-family, conferring the ability to switch between compact and elongated conformers. While the folded, membrane-distal ectodomain is buried within the VSG layer for compact conformers, their elongated counterparts would enable the extension beyond it. This dynamic behavior enables ISGs to maintain a low immunogenic footprint while still allowing them to engage with the host environment when necessary. Our findings add further evidence to a dynamic molecular organization of trypanosome surface antigens wherein intrinsic disorder underpins the characteristics of a highly flexible ISG proteome to circumvent the constraints imposed by the VSG coat.

• MeSH
• lidé MeSH
• membránové glykoproteiny metabolismus   MeSH
• protozoální proteiny metabolismus   MeSH
• trypanosomové variantní povrchové glykoproteiny * metabolismus   MeSH
• trypanozomóza africká * parazitologie   imunologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• membránové glykoproteiny MeSH
• protozoální proteiny MeSH
• trypanosomové variantní povrchové glykoproteiny * MeSH

Studies have shown that depending on the substitution pattern, microtubule (MT)-targeting 1,2,4-triazolo[1,5-a]pyrimidines (TPDs) can produce different cellular responses in mammalian cells that may be due to these compounds interacting with distinct binding sites within the MT structure. Selected TPDs are also potently bioactive against the causative agent of human African trypanosomiasis, Trypanosoma brucei, both in vitro and in vivo. So far, however, there has been no direct evidence of tubulin engagement by these TPDs in T. brucei. Therefore, to enable further investigation of anti-trypanosomal TPDs, a TPD derivative amenable to photoaffinity labeling (PAL) was designed, synthesized, and evaluated in PAL experiments using HEK293 cells and T. brucei. The data arising confirmed specific labeling of T. brucei tubulin. In addition, proteomic data revealed differences in the labeling profiles of tubulin between HEK293 and T. brucei, suggesting structural differences between the TPD binding site(s) in mammalian and trypanosomal tubulin.

• Klíčová slova
• African trypanosomiasis, Trypanosoma brucei, microtubules, photoaffinity labeling, seventh site, triazolopyrimidines, vinca site,
• MeSH
• HEK293 buňky MeSH
• lidé MeSH
• proteomika MeSH
• pyrimidiny chemie   MeSH
• savci metabolismus   MeSH
• trypanocidální látky * chemie   MeSH
• Trypanosoma brucei brucei * metabolismus   MeSH
• trypanozomóza africká * farmakoterapie   MeSH
• tubulin metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• pyrimidiny MeSH
• trypanocidální látky * MeSH
• tubulin MeSH

Anogeissus leiocarpus (DC.) Guill. & Perr. belongs to the family Combretaceae and is used both by African traditional medical practitioners and livestock rearers to treat diseases such as African trypanosomiasis, animal diarrhoea, asthma, cancer, cough, diabetes, dysentery, erectile dysfunction, fever, giardiasis, helminthiases, meningitis, menstrual disorders, monkeypox, oral infections, poliomyelitis, sickle cell anaemia, snake bites, toothache, urinary schistosomiasis, and yellow fever. Some of these activities have been associated with the presence of polyphenols in the plant which include ellagic acid derivatives, flavonoids, stilbenes, tannins, and triterpenes. Several bioactive molecules have been identified from A. leiocarpus. These include the main active constituents, ellagitannins, ellagic acid derivates, flavonoids and triterpenes. Pharmacological studies have confirmed its antibacterial, antifungal, antihyperglycemic, antihypertensive, antimalarial, antioxidative, antiparasitic, antitumour and anti-ulcer effects. The stem bark has been investigated mainly for biological activities and phytochemistry, and it is the most mentioned plant part highlighted by the traditional users in ethnomedicinal surveys. In vitro and in vivo models, which revealed a wide range of pharmacological actions against parasites causing helminthiasis, leishmaniasis, malaria and trypanosomiasis, have been used to study compounds from A. leiocarpus. Because of its uses in African traditional medicine and veterinary practices, A. leiocarpus has received considerable attention from researchers. The current review provides a comprehensive overview and critical appraisal of scientific reports on A. leiocarpus, covering its traditional uses, pharmacological activities and phytochemistry.

• Klíčová slova
• Anogeissus leiocarpus, Anthelmintics, Antimicrobial, Combretaceae, Ellagitannins,
• MeSH
• Combretaceae * chemie   MeSH
• fytonutrienty * farmakologie   izolace a purifikace   MeSH
• kůra rostlin chemie   MeSH
• lidé MeSH
• rostlinné extrakty farmakologie   chemie   MeSH
• tradiční africká medicína * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• fytonutrienty * MeSH
• rostlinné extrakty MeSH

• MeSH
• lidé MeSH
• trypanocidální látky terapeutické užití   MeSH
• trypanozomóza africká farmakoterapie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• trypanocidální látky MeSH

Trypanosoma brucei, a protist responsible for human African trypanosomiasis (sleeping sickness), is transmitted by the tsetse fly where the procyclic forms of the parasite develop in the proline-rich (1-2 mM) and glucose-depleted digestive tract. Proline is essential for the midgut colonization of the parasite in the insect vector, however other carbon sources could be available and used to feed its central metabolism. Here we show that procyclic trypanosomes can consume and metabolize metabolic intermediates, including those excreted from glucose catabolism (succinate, alanine and pyruvate), with the exception of acetate, which is the ultimate end-product excreted by the parasite. Among the tested metabolites, tricarboxylic acid (TCA) cycle intermediates (succinate, malate and α-ketoglutarate) stimulated growth of the parasite in the presence of 2 mM proline. The pathways used for their metabolism were mapped by proton-NMR metabolic profiling and phenotypic analyses of thirteen RNAi and/or null mutants affecting central carbon metabolism. We showed that (i) malate is converted to succinate by both the reducing and oxidative branches of the TCA cycle, which demonstrates that procyclic trypanosomes can use the full TCA cycle, (ii) the enormous rate of α-ketoglutarate consumption (15-times higher than glucose) is possible thanks to the balanced production and consumption of NADH at the substrate level and (iii) α-ketoglutarate is toxic for trypanosomes if not appropriately metabolized as observed for an α-ketoglutarate dehydrogenase null mutant. In addition, epimastigotes produced from procyclics upon overexpression of RBP6 showed a growth defect in the presence of 2 mM proline, which is rescued by α-ketoglutarate, suggesting that physiological amounts of proline are not sufficient per se for the development of trypanosomes in the fly. In conclusion, these data show that trypanosomes can metabolize multiple metabolites, in addition to proline, which allows them to confront challenging environments in the fly.

• MeSH
• citrátový cyklus účinky léků   MeSH
• glukosa metabolismus   MeSH
• hmyz - vektory parazitologie   MeSH
• moucha tse-tse účinky léků   parazitologie   MeSH
• oxidace-redukce účinky léků   MeSH
• prolin metabolismus   farmakologie   MeSH
• RNA interference fyziologie   MeSH
• Trypanosoma brucei brucei účinky léků   metabolismus   MeSH
• Trypanosoma účinky léků   metabolismus   MeSH
• trypanozomóza africká farmakoterapie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glukosa MeSH
• prolin MeSH

Trypanosoma brucei, the causative agent of the African sleeping sickness of humans, and other kinetoplastid flagellates belong to the eukarytotic supergroup Excavata. This early-branching model protist is known for a broad range of unique features. As it is amenable to most techniques of forward and reverse genetics, T. brucei was subject to several studies of its iron-sulfur (Fe/S) protein biogenesis and thus represents the best studied excavate eukaryote. Here we review what is known about the Fe/S protein biogenesis of T. brucei, and focus especially on the comparative and evolutionary interesting aspects. We also explore the connections between the well-known and quite conserved ISC and CIA machineries and the tRNA thiolation pathway. Moreover, the Fe/S cluster protein biogenesis is dissected in the procyclic stage of T. brucei which has an active mitochondrion, as well as in its pathogenic bloodstream stage with a metabolically repressed organelle. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.

• Klíčová slova
• Fe/S cluster, Kinetoplastida, Protist, Trypanosoma brucei,
• MeSH
• biosyntetické dráhy * MeSH
• lidé MeSH
• mitochondrie metabolismus   MeSH
• proteiny obsahující železo a síru biosyntéza   MeSH
• protozoální proteiny biosyntéza   MeSH
• RNA transferová metabolismus   MeSH
• síra metabolismus   MeSH
• Trypanosoma brucei brucei metabolismus   MeSH
• trypanozomóza africká parazitologie   MeSH
• železo metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• proteiny obsahující železo a síru MeSH
• protozoální proteiny MeSH
• RNA transferová MeSH
• síra MeSH
• železo MeSH

The risk of acquiring a transfusion-induced infection in Zambia was studied for the first time. Blood slide examination of donors, despite the insensitivity of the method, established malaria as the most serious hazard. The species involved was Plasmodium falciparum, the cause of cerebral malaria, and which could be rapidly fatal in a non-immune host visiting an endemic area. Microfilariae of Dipetalonema perstans and Wuchereria bancrofti were also found in donor populations. While no disease may be induced, allergic reactions due to the breakdown products of dead microfilariae may manifest themselves. Several cases of transfusion-induced malaria, a case of relapsing fever and a case of rhodesian trypanosomiasis are reported. Toxoplasmosis and kalatazar, which may also be transfusion-induced, are both known to occur in the country but no cases were observed. It is emphasized that prophylactic measures should be mandatory in areas where no regular, screened, donor panel is available. The awareness and ackowledgement of the risk of transfusion-induced infections may be the best safeguard against the serious consequences in developing countries.

• MeSH
• biochemická analýza krve MeSH
• dítě MeSH
• dospělí MeSH
• infekce bakteriemi rodu Borrelia etiologie   MeSH
• lidé MeSH
• malárie etiologie   MeSH
• Plasmodium falciparum MeSH
• potransfuzní reakce * MeSH
• trypanozomóza africká etiologie   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Geografické názvy
• Zambie MeSH

Cytosolic and nuclear iron-sulphur (Fe/S) proteins include essential components involved in protein translation, DNA synthesis and DNA repair. In yeast and human cells, assembly of their Fe/S cofactor is accomplished by the CIA (cytosolic iron-sulphur protein assembly) machinery comprised of some 10 proteins. To investigate the extent of conservation of the CIA pathway, we examined its importance in the early-branching eukaryote Trypanosoma brucei that encodes all known CIA factors. Upon RNAi-mediated ablation of individual, early-acting CIA proteins, no major defects were observed in both procyclic and bloodstream stages. In contrast, parallel depletion of two CIA components was lethal, and severely diminished cytosolic aconitase activity lending support for a direct role of the CIA proteins in cytosolic Fe/S protein biogenesis. In support of this conclusion, the T. brucei CIA proteins complemented the growth defects of their respective yeast CIA depletion mutants. Finally, the T. brucei CIA factor Tah18 was characterized as a flavoprotein, while its binding partner Dre2 functions as a Fe/S protein. Together, our results demonstrate the essential and conserved function of the CIA pathway in cytosolic Fe/S protein assembly in both developmental stages of this representative of supergroup Excavata.

• MeSH
• cytosol metabolismus   MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• proteiny obsahující železo a síru chemie   genetika   metabolismus   MeSH
• protozoální proteiny chemie   genetika   metabolismus   MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• terciární struktura proteinů MeSH
• Trypanosoma brucei brucei chemie   genetika   růst a vývoj   metabolismus   MeSH
• trypanozomóza africká parazitologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• proteiny obsahující železo a síru MeSH
• protozoální proteiny MeSH