Jako enterální výživa se označuje podávání umělé výživy do trávicího traktu. Je přirozenou cestou přívodu živin nemocným v případě, že není možný nebo dostatečný příjem běžné stravy. Zahrnuje podávání přípravků určených k popíjení (orální nutriční suplementa, sipping) nebo výživu určenou pro podávání sondou. Podmínkou je funkční trávicí trakt. Efektivní nutriční podpora formou enterální výživy vyžaduje dobrou spolupráci nemocného, proto je nezbytné pacienty dostatečně informovat o jejím užívání. Důležitou úlohu v edukaci i nastavení enterální výživy má nutriční terapeut.
Enteral nutrition refers to the administration of artificial nutrition into the digestive tract of alimentary tract. It is a natural way of supplying nutrients to patients when the intake of normal diet is not possible or sufficient. It involves the administration of preparations intended for ingestion (oral nutritional supplements, sipping) or nutrition intended for administration by tube. A functional digestive tract is a prerequisite. Effective nutritional support in the form of enteral nutrition requires good patient’s cooperation; it is therefore essential for the patients to receive sufficient information about its use. The nutritional therapist has an important role in the education and setting of enteral nutrition.
Haptoglobin is a plasma protein of mammals that plays a crucial role in vascular homeostasis by binding free haemoglobin released from ruptured red blood cells. Trypanosoma brucei can exploit this by internalising haptoglobin-haemoglobin complex to acquire host haem. Here, we investigated the impact of haptoglobin deficiency (Hp-/-) on T. brucei brucei infection and the parasite ́s capacity to internalise haemoglobin in a Hp-/- mouse model. The infected Hp-/- mice exhibited normal disease progression, with minimal weight loss and no apparent organ pathology, similarly to control mice. While the proteomic profile of mouse sera significantly changed in response to T. b. brucei, no differences in the infection response markers of blood plasma between Hp-/- and control Black mice were observed. Similarly, very few quantitative differences were observed between the proteomes of parasites harvested from Hp-/- and Black mice, including both endogenous proteins and internalised host proteins. While haptoglobin was indeed absent from parasites isolated from Hp-/-mice, haemoglobin peptides were unexpectedly detected in parasites from both Hp-/- and Black mice. Combined, the data support the dispensability of haptoglobin for haemoglobin internalisation by T. b. brucei during infection in mice. Since the trypanosomes knock-outs for their haptoglobin-haemoglobin receptor (HpHbR) internalised significantly less haemoglobin from Hp-/- mice compared to those isolated from Black mice, it suggests that T. b. brucei employs also an HpHbR-independent haptoglobin-mediated mode for haemoglobin internalisation. Our study reveals a so-far hidden flexibility of haemoglobin acquisition by T. b. brucei and offers novel insights into alternative haemoglobin uptake pathways.
- MeSH
- haptoglobiny * genetika metabolismus MeSH
- hemoglobiny * metabolismus MeSH
- modely nemocí na zvířatech MeSH
- myši inbrední C57BL MeSH
- myši knockoutované * MeSH
- myši MeSH
- proteomika metody MeSH
- Trypanosoma brucei brucei * metabolismus MeSH
- trypanozomóza africká * parazitologie imunologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
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- Klíčová slova
- sipping, nazojejunální sonda, Perkutánní endoskopická gastrostomie PEG, Perorální nutriční suplementy,
- MeSH
- endoskopie trávicího systému MeSH
- enterální výživa MeSH
- gastrostomie MeSH
- metody výživy MeSH
- nádory MeSH
- nutriční podpora metody MeSH
- pacienti MeSH
- podvýživa prevence a kontrola terapie MeSH
- potrava speciální MeSH
- potraviny pro zvláštní výživu MeSH
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 human parasite Trypanosoma brucei does not synthesize heme de novo and instead relies entirely on heme supplied by its vertebrate host or its insect vector, the tsetse fly. In the host bloodstream T. brucei scavenges heme via haptoglobin-hemoglobin (HpHb) receptor-mediated endocytosis occurring in the flagellar pocket. However, in the procyclic developmental stage, in which T. brucei is confined to the tsetse fly midgut, this receptor is apparently not expressed, suggesting that T. brucei takes up heme by a different, unknown route. To define this alternative route, we functionally characterized heme transporter TbHrg in the procyclic stage. RNAi-induced down-regulation of TbHrg in heme-limited culture conditions resulted in slower proliferation, decreased cellular heme, and marked changes in cellular morphology so that the cells resemble mesocyclic trypomastigotes. Nevertheless, the TbHrg KO developed normally in the tsetse flies at rates comparable with wild-type cells. T. brucei cells overexpressing TbHrg displayed up-regulation of the early procyclin GPEET and down-regulation of the late procyclin EP1, two proteins coating the T. brucei surface in the procyclic stage. Light microscopy of immunostained TbHrg indicated localization to the flagellar membrane, and scanning electron microscopy revealed more intense TbHrg accumulation toward the flagellar pocket. Based on these findings, we postulate that T. brucei senses heme levels via the flagellar TbHrg protein. Heme deprivation in the tsetse fly anterior midgut might represent an environmental stimulus involved in the transformation of this important human parasite, possibly through metabolic remodeling.
- MeSH
- biologický transport MeSH
- down regulace MeSH
- flagella metabolismus MeSH
- hem metabolismus MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- membránové transportní proteiny metabolismus MeSH
- mikroskopie elektronová rastrovací MeSH
- moucha tse-tse parazitologie MeSH
- proliferace buněk MeSH
- protozoální proteiny metabolismus MeSH
- receptory buněčného povrchu metabolismus MeSH
- RNA interference MeSH
- sekvence aminokyselin MeSH
- stadia vývoje MeSH
- transgeny MeSH
- Trypanosoma brucei brucei metabolismus MeSH
- vývojová regulace genové exprese MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
A serie of O-substituted N-2-phenylcyclopropylcarbamates was prepared and characterized. These carbamates were tested as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). It was found, that these compounds exhibit moderate inhibition activity with values of IC50 in the range of 54.8-94.4 μM (for AChE) and up to 5.8 μM (for BChE). The AChE/BChE selectivity for each carbamate was calculated. These values varied from 0.50 to 9.46, two carbamate derivatives inhibited only AChE selectively. The most promising derivative was prepared in all optically pure forms (four isomers). It was found that individual stereoisomers differed only slightly in the inhibition ability. The cytotoxicity of all carbamates was evaluated using the standard in vitro test with Jurkat cells. With regard to their inhibition activity and cytotoxicity as well as easy preparation, O-substituted N-2-phenylcyclopropylcarbamates can be considered as promising compounds for potential medicinal applications.
- MeSH
- acetylcholinesterasa metabolismus MeSH
- butyrylcholinesterasa metabolismus MeSH
- cholinesterasové inhibitory chemická syntéza chemie farmakologie MeSH
- Jurkat buňky MeSH
- karbamáty chemická syntéza chemie farmakologie MeSH
- lidé MeSH
- molekulární struktura MeSH
- viabilita buněk účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
ABC transporter mitochondrial 1 (Atm1) and multidrug resistance-like 1 (Mdl) are mitochondrial ABC transporters. Although Atm1 was recently suggested to transport different forms of glutathione from the mitochondrion, which are used for iron-sulfur (Fe-S) cluster maturation in the cytosol, the function of Mdl remains elusive. In Trypanosoma brucei, we identified one homolog of each of these genes, TbAtm and TbMdl, which were downregulated either separately or simultaneously using RNA interference. Individual depletion of TbAtm and TbMdl led to limited growth defects. In cells downregulated for TbAtm, the enzymatic activities of the Fe-S cluster proteins aconitase and fumarase significantly decreased in the cytosol but not in the mitochondrion. Downregulation of TbMdl did not cause any change in activities of the Fe-S proteins. Unexpectedly, the simultaneous downregulation of TbAtm and TbMdl did not result in any growth defect, nor were the Fe-S cluster protein activities altered in either the cytosolic or mitochondrial compartments. Additionally, TbAtm and TbMdl were able to partially restore the growth of the Saccharomyces cerevisiae Δatm1 and Δmdl2 null mutants, respectively. Because T. brucei completely lost the heme b biosynthesis pathway, this cofactor has to be obtained from the host. Based on our results, TbMdl is a candidate for mitochondrial import of heme b, which was markedly decreased in both TbMdl and TbAtm + TbMdl knockdowns. Moreover, the levels of heme a were strongly decreased in the same knockdowns, suggesting that TbMdl plays a key role in heme a biosynthesis, thus affecting the overall heme homeostasis in T. brucei.
- MeSH
- ABC transportéry antagonisté a inhibitory genetika metabolismus MeSH
- akonitáthydratasa metabolismus MeSH
- biologické modely MeSH
- cytosol metabolismus MeSH
- fumarasa metabolismus MeSH
- fylogeneze MeSH
- genový knockdown MeSH
- hem metabolismus MeSH
- mitochondrie metabolismus MeSH
- proteiny obsahující železo a síru metabolismus MeSH
- proteiny spojené s mnohočetnou rezistencí k lékům antagonisté a inhibitory genetika metabolismus MeSH
- protozoální geny MeSH
- protozoální proteiny antagonisté a inhibitory genetika metabolismus MeSH
- Saccharomyces cerevisiae genetika metabolismus MeSH
- testy genetické komplementace MeSH
- Trypanosoma brucei brucei genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
