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
Aquaglyceroporins (AQPs) are membrane proteins that function in osmoregulation and the uptake of low molecular weight solutes, in particular glycerol and urea. The AQP family is highly conserved, with two major subfamilies having arisen very early in prokaryote evolution and retained by eukaryotes. A complex evolutionary history indicates multiple lineage-specific expansions, losses and not uncommonly a complete loss. Consequently, the AQP family is highly evolvable and has been associated with significant events in life on Earth. In the African trypanosomes, a role for the AQP2 paralogue, in sensitivity to two chemotherapeutic agents, pentamidine and melarsoprol, is well established, albeit with the mechanisms for cell entry and resistance unclear until very recently. Here, we discuss AQP evolution, structure and mechanisms by which AQPs impact drug sensitivity, suggesting that AQP2 stability is highly sensitive to mutation while serving as the major uptake pathway for pentamidine.
Catalase is a widespread heme-containing enzyme, which converts hydrogen peroxide (H2 O2 ) to water and molecular oxygen, thereby protecting cells from the toxic effects of H2 O2 . Trypanosoma brucei is an aerobic protist, which conspicuously lacks this potent enzyme, present in virtually all organisms exposed to oxidative stress. To uncover the reasons for its absence in T. brucei, we overexpressed different catalases in procyclic and bloodstream stages of the parasite. The heterologous enzymes originated from the related insect-confined trypanosomatid Crithidia fasciculata and the human. While the trypanosomatid enzyme (cCAT) operates at low temperatures, its human homolog (hCAT) is adapted to the warm-blooded environment. Despite the presence of peroxisomal targeting signal in hCAT, both human and C. fasciculata catalases localized to the cytosol of T. brucei. Even though cCAT was efficiently expressed in both life cycle stages, the enzyme was active in the procyclic stage, increasing cell's resistance to the H2 O2 stress, yet its activity was suppressed in the cultured bloodstream stage. Surprisingly, following the expression of hCAT, the ability to establish the T. brucei infection in the tsetse fly midgut was compromised. In the mouse model, hCAT attenuated parasitemia and, consequently, increased the host's survival. Hence, we suggest that the activity of catalase in T. brucei is beneficial in vitro, yet it becomes detrimental for parasite's proliferation in both invertebrate and vertebrate hosts, leading to an inability to carry this, otherwise omnipresent, enzyme.
- MeSH
- hmyz účinky léků růst a vývoj metabolismus MeSH
- katalasa metabolismus MeSH
- peroxid vodíku farmakologie MeSH
- Trypanosoma brucei brucei účinky léků metabolismus MeSH
- Trypanosoma účinky léků metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The effect of the combination of α-pinene and β-caryophyllene on the proliferation of the Trypanosoma evansi was analyzed. These compounds were added individually and in combination at different concentrations to T. evansi cultures, and the in vivo study used mice of 1.0 and 1.5 mL kg−1 of α-pinene and β-caryophyllene individually and in combination against T. evansi. In order to evaluate the in vitro safety, lymphocytes and VERO cells were assessed using tetrazolium salt (MTT) assay. The trypanocidal effect of α-pinene and β-caryophyllene was observed in vitro when applied independently or combined at 0.5, 1 and 2% concentrations. The combination effect showed a faster trypanocidal effect when compared to chemotherapy (diminazene aceturate – D.A.). Concerning the in vivo evaluation, α-pinene + β-caryophyllene at 1.0 mL kg−1 was able to extend animal longevity and showed 83.33% curative efficacy, a superior result when compared to D.A. (16.66%). The MTT assay showed that the assessed compounds do not present toxicity to used cells. Also, in vivo safety evaluation of α-pinene + β-caryophyllene at 1.0 mL kg−1 not altered the aminotransferases levels in serum. Combination between α-pinene and β-caryophyllene shows in vitro and in vivo trypanocidal activity against T. evansi, in a safe dose.
- MeSH
- modely u zvířat MeSH
- monoterpeny aplikace a dávkování farmakologie chemie MeSH
- myši MeSH
- seskviterpeny aplikace a dávkování farmakologie chemie MeSH
- trypanocidální látky aplikace a dávkování MeSH
- Trypanosoma izolace a purifikace účinky léků MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
Antimicrobial diazanaphthalenes are indispensable in the treatment of various infections. The quinoxaline scaffold possesses unique physicochemical properties and provides a possibility of a great number of targeted modifications. Quinoxaline-based compounds have a wide range of promising biological properties; therefore a special attention is paid to them for research and designing of new drugs. In fact, quinoxaline can be considered as a privileged structure. The scaffold can be easily and rapidly constructed, which emphasizes the significance of this favourable structure. The review is focused on recently reported potential antibacterial, antimycobacterial, antifungal and antiprotozoal agents derived from the quinoxaline scaffold, their mechanism of action and structure-activity relationships. A brief classification of synthetic pathways of quinoxaline derivatives is provided too.
- MeSH
- antiinfekční látky chemická syntéza chemie farmakologie MeSH
- chinoxaliny chemická syntéza chemie farmakologie MeSH
- gramnegativní bakterie účinky léků MeSH
- grampozitivní bakterie účinky léků MeSH
- houby účinky léků MeSH
- mikrobiální testy citlivosti MeSH
- mnohočetná bakteriální léková rezistence účinky léků MeSH
- Mycobacterium tuberculosis účinky léků MeSH
- Plasmodium účinky léků MeSH
- racionální návrh léčiv * MeSH
- Trypanosoma účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
WHO technical report series, ISSN 0512-3054 984
x, 237 s. : il. ; 22 cm.
- MeSH
- antiprotozoální látky * terapeutické užití MeSH
- epidemiologické metody * MeSH
- infekce přenášené vektorem MeSH
- parazitární nemoci * diagnóza farmakoterapie prevence a kontrola MeSH
- surveillance populace * metody MeSH
- Trypanosoma * klasifikace patogenita účinky léků MeSH
- trypanozomóza africká epidemiologie klasifikace prevence a kontrola MeSH
- Publikační typ
- monografie MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- cestovní a tropická medicína
- parazitologie
- infekční lékařství
- epidemiologie
- NLK Publikační typ
- publikace WHO
WHO technical report series ; no. 739
127 s. : il., tab. ; 20 cm
- MeSH
- epidemiologie organizace a řízení MeSH
- kontrola infekčních nemocí MeSH
- parazitologie MeSH
- socioekonomické faktory MeSH
- Trypanosoma izolace a purifikace klasifikace metabolismus patogenita růst a vývoj účinky léků MeSH
- trypanozomóza africká diagnóza farmakoterapie patofyziologie patologie MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- infekční lékařství
- NLK Publikační typ
- publikace WHO
