In evolution, genes survived that could code for metabolic pathways, promoting long term survival during famines or fasting when suffering from trauma, disease or during physiological growth. This requires utilization of substrates, already present in some form in the body. Carbohydrate stores are limited and to survive long, their utilization is restricted to survival pathways, by inhibiting glucose oxidation and glycogen synthesis. This leads to insulin resistance and spares muscle protein, because being the main supplier of carbon for new glucose production. In these survival pathways, part of the glucose is degraded in glycolysis in peripheral (muscle) tissues to pyruvate and lactate (Warburg effect), which are partly reutilized for glucose formation in liver and kidney, completing the Cori-cycle. Another part of the glucose taken up by muscle contributes, together with muscle derived amino acids, to the production of substrates consisting of a complete amino acid mix but extra non-essential amino acids like glutamine, alanine, glycine and proline. These support cell proliferation, matrix deposition and redox regulation in tissues, specifically active in host response and during growth. In these tissues, also glucose is taken up delivering glycolytic intermediates, that branch off and act as building blocks and produce reducing equivalents. Lactate is also produced and released in the circulation, adding to the lactate released by muscle in the Cori-cycle and completing secondary glucose cycles. Increased fluxes through these cycles lead to modest hyperglycemia and hyperlactatemia in states of healthy growth and disease and are often misinterpreted as induced by hypoxia.

• Klíčová slova
• Cori-cycle, Growth, Inflammation, Insulin resistance, Trauma/Disease, Warburg effect,
• MeSH
• glukosa metabolismus   MeSH
• glykolýza fyziologie   MeSH
• játra metabolismus   MeSH
• kosterní svaly metabolismus   MeSH
• kyselina mléčná metabolismus   MeSH
• kyselina pyrohroznová metabolismus   MeSH
• ledviny metabolismus   MeSH
• lidé MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• glukosa MeSH
• kyselina mléčná MeSH
• kyselina pyrohroznová MeSH

The main bottleneck in the return of industrial butanol production from renewable feedstock through acetone-butanol-ethanol (ABE) fermentation by clostridia, such as Clostridium beijerinckii, is the low final butanol concentration. The problem is caused by the high toxicity of butanol to the production cells, and therefore, understanding the mechanisms by which clostridia react to butanol shock is of key importance. Detailed analyses of transcriptome data that were obtained after butanol shock and their comparison with data from standard ABE fermentation have resulted in new findings, while confirmed expected population responses. Although butanol shock resulted in upregulation of heat shock protein genes, their regulation is different than was assumed based on standard ABE fermentation transcriptome data. While glucose uptake, glycolysis, and acidogenesis genes were downregulated after butanol shock, solventogenesis genes were upregulated. Cyclopropanation of fatty acids and formation of plasmalogens seem to be significant processes involved in cell membrane stabilization in the presence of butanol. Surprisingly, one of the three identified Agr quorum-sensing system genes was upregulated. Upregulation of several putative butanol efflux pumps was described after butanol addition and a large putative polyketide gene cluster was found, the transcription of which seemed to depend on the concentration of butanol.

• Klíčová slova
• Clostridium beijerinckii, ABE fermentation, butanol shock, transcriptome analysis,
• MeSH
• biologický transport genetika   MeSH
• bioreaktory mikrobiologie   MeSH
• buněčná membrána metabolismus   MeSH
• butanoly toxicita   MeSH
• Clostridium beijerinckii účinky léků   genetika   metabolismus   MeSH
• fyziologický stres genetika   MeSH
• glukosa metabolismus   MeSH
• glykolýza genetika   fyziologie   MeSH
• mastné kyseliny metabolismus   MeSH
• plasmalogeny biosyntéza   MeSH
• proteiny tepelného šoku metabolismus   MeSH
• quorum sensing genetika   MeSH
• stanovení celkové genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• butanoly MeSH
• glukosa MeSH
• mastné kyseliny MeSH
• plasmalogeny MeSH
• proteiny tepelného šoku MeSH

Mycobacterium tuberculosis (Mtb) causes both acute tuberculosis and latent, symptom-free infection that affects roughly one-third of the world's population. It is a globally important pathogen that poses multiple dangers. Mtb reprograms its metabolism in response to the host niche, and this adaptation contributes to its pathogenicity. Knowledge of the metabolic regulation mechanisms in Mtb is still limited. Pyruvate kinase, involved in the late stage of glycolysis, helps link various metabolic routes together. Here, we demonstrate that Mtb pyruvate kinase (Mtb PYK) predominantly catalyzes the reaction leading to the production of pyruvate, but its activity is influenced by multiple metabolites from closely interlinked pathways that act as allosteric regulators (activators and inhibitors). We identified allosteric activators and inhibitors of Mtb PYK originating from glycolysis, citrate cycle, nucleotide/nucleoside inter-conversion related pathways that had not been described so far. Enzyme was found to be activated by fructose-1,6-bisphosphate, ribose-5-phosphate, adenine, adenosine, hypoxanthine, inosine, L-2-phosphoglycerate, l-aspartate, glycerol-2-phosphate, glycerol-3-phosphate. On the other hand thiamine pyrophosphate, glyceraldehyde-3-phosphate and L-malate were identified as inhibitors of Mtb PYK. The detailed kinetic analysis indicated a morpheein model of Mtb PYK allosteric control which is strictly dependent on Mg2+ and substantially increased by the co-presence of Mg2+ and K+.

• Klíčová slova
• Allosteric regulation, Ions, Metabolism, Metabolites, Mycobacterium tuberculosis, Pyruvate kinase,
• MeSH
• alosterická regulace fyziologie   MeSH
• glykolýza fyziologie   MeSH
• katalýza MeSH
• kinetika MeSH
• metabolomika metody   MeSH
• Mycobacterium tuberculosis enzymologie   metabolismus   MeSH
• pyruvátkinasa metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• pyruvátkinasa MeSH

Trypanosoma brucei brucei has two distinct developmental stages, the procyclic stage in the insect and the bloodstream stage in the mammalian host. The significance of each developmental stage is punctuated by specific changes in metabolism. In the insect, T. b. brucei is strictly dependent on mitochondrial function and thus respiration to generate the bulk of its ATP, whereas in the mammalian host it relies heavily on glycolysis. These observations have raised questions about the importance of mitochondrial function in the bloodstream stage. Peculiarly, akinetoplastic strains of Trypanosoma brucei evansi that lack mitochondrial DNA do exist in the wild and are developmentally locked in the glycolysis-dependent bloodstream stage. Using RNAi we show that two mitochondrion-imported proteins, mitochondrial RNA polymerase and guide RNA associated protein 1, are still imported into the nucleic acids-lacking organelle of T. b. evansi, making the need for these proteins futile. We also show that, like in the T. b. brucei procyclic stage, the mitochondria of both bloodstream stage of T. b. brucei and T. b. evansi import various tRNAs, including those that undergo thiolation. However, we were unable to detect mitochondrial thiolation in the akinetoplastic organelle. Taken together, these data suggest a lack of connection between nuclear and mitochondrial communication in strains of T. b. evansi that lost mitochondrial genome and that do not required an insect vector for survival.

• MeSH
• adenosintrifosfát metabolismus   MeSH
• buněčné jádro genetika   metabolismus   MeSH
• DNA řízené RNA-polymerasy genetika   metabolismus   MeSH
• geneticky modifikované organismy MeSH
• glykolýza fyziologie   MeSH
• guide RNA, Kinetoplastida metabolismus   MeSH
• kinetoplastová DNA metabolismus   MeSH
• mezibuněčná komunikace MeSH
• mitochondrie genetika   metabolismus   MeSH
• oxidativní fosforylace MeSH
• proteiny genetika   metabolismus   MeSH
• RNA interference MeSH
• RNA transferová genetika   metabolismus   MeSH
• transport proteinů MeSH
• transport RNA MeSH
• Trypanosoma fyziologie   MeSH
• trypanozomiáza parazitologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• adenosintrifosfát MeSH
• DNA řízené RNA-polymerasy MeSH
• guide RNA, Kinetoplastida MeSH
• kinetoplastová DNA MeSH
• proteiny MeSH
• RNA transferová MeSH

BACKGROUND: The purpose was to examine the energy cost and cardiorespiratory demands of nunchaku exercise, one of the martial arts performed with an instrument. METHODS: Nine male martial art practitioners (age 26.4 (+/-SD) 3.4 years, VO2max 54.1+/-9.0 ml x kg(-1)x min(-1)) completed three nunchaku exercise trials, lasting 20 sec, 1 min and 5 min. Cardiorespiratory response was followed by the Cosmed K4 portable respiratory analysis system. MEASURES: Oxygen consumption (VO2) was determined during pre-exercise rest, the exercise period and the recovery phase (10-15 min), and energy release from lactate (La) production was calculated assuming that an increase of 1 mmol x l(-1) corresponds to aVO2 of 3 ml O2 (di Prampero 1981). RESULTS: The overall energy cost of nunchaku exercise attained 76+/-16 kJ (229+/-48 kJ x min(-1)), 98+/-23 kJ and 271+/-72 kJ (54+/-14 kJ x min(-1)) for the 20 sec, 1 min and 5 min nunchaku exercise, respectively. From the point of view of the energy sources (alactic, lactic and oxidative), 20-sec performance was essentially "anaerobic alactic" (69:15:16%), 1 min exercise "alactic-oxidative" (49:16:35%) and 5-min performance an "oxidative" exercise workload (17% alactic: 6% lactic: 77% oxidative, respectively). The intensity of the exercise, on the average, corresponded to 43, 49 and 56% of VO2max and 69, 72 and 76% of HRmax, for the 20 sec, 1 min and 5 min exercises, respectively. CONCLUSIONS: Nunchaku exercise elicits high alactic and oxidative energy sources, but its demand for anaerobic glycolytic pathway seem to be relatively low, regardless the duration of the exercise. The energy cost (EC) for 20-sec to 5-min lasting exercise may be described by power function EC=10.84.t(-0.522) (n=24, r2=0.95), where EC is in kJ x min(-1) x kg(-1) and t in seconds.

• MeSH
• anaerobní práh fyziologie   MeSH
• analýza rozptylu MeSH
• bojové sporty fyziologie   MeSH
• časové faktory MeSH
• dospělí MeSH
• energetický metabolismus * fyziologie   MeSH
• glykolýza fyziologie   MeSH
• kyslík krev   MeSH
• laktáty krev   MeSH
• lidé MeSH
• oxid uhličitý krev   MeSH
• plíce fyziologie   MeSH
• plicní ventilace fyziologie   MeSH
• regresní analýza MeSH
• sportovní vybavení MeSH
• spotřeba kyslíku fyziologie   MeSH
• srdce fyziologie   MeSH
• srdeční frekvence fyziologie   MeSH
• výměna plynů v plicích fyziologie   MeSH
• zátěžový test MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kyslík MeSH
• laktáty MeSH
• oxid uhličitý MeSH

Since nitric oxide (NO) in many cells is involved in energy metabolism, the aim of this study was to evaluate the role of isosorbide dinitrate (ISDN), a NO donor, in energy metabolism of rat reticulocytes, particularly due to their high content of hemoglobin--an effective scavenger of NO. Rat reticulocyte-rich red blood cell suspensions were aerobically incubated in the absence (control) or in the presence of different concentrations of ISDN. ISDN decreased total and coupled oxygen consumption (p<0.05) while increased uncoupled oxygen consumption (p<0.05) in a dose- and time-dependent manner. This was followed by enhancement of glycolysis, as measured by increased glucose consumption and lactate accumulation (p<0.05). Levels of all glycolytic intermediates in the presence of ISDN indicate only stimulation of pyruvate kinase activity. ISDN did not alter the concentration of ATP, while increased ADP and AMP levels (p>0.05). In rat reticulocytes under steady-state conditions, 95.4% of overall energy was produced by oxidative phosphorylation but only 4.6% by glycolysis. Due to a reduced coupled oxygen consumption in the presence of ISDN, ATP production via oxidative phosphorylation was significantly diminished. A simultaneous increase of glycolytic ATP production is not enough to ensure constant ATP production. The calculated mean ATP turnover time was prolonged by 199% in the presence of 1.5 mmol/l ISDN. In conclusion, ISDN a) inhibited total and coupled respiration but enhanced uncoupled respiration, b) stimulated glycolysis, c) decreased ATP production and d) prolonged ATP turnover time in rat reticulocytes. These effects were mediated by NO as the effector molecule.

• MeSH
• adenosindifosfát metabolismus   MeSH
• adenosinmonofosfát metabolismus   MeSH
• adenosintrifosfát metabolismus   MeSH
• donory oxidu dusnatého farmakologie   MeSH
• energetický metabolismus účinky léků   MeSH
• glykolýza účinky léků   fyziologie   MeSH
• isosorbiddinitrát farmakologie   MeSH
• krysa rodu Rattus MeSH
• oxid dusnatý metabolismus   MeSH
• oxidativní fosforylace účinky léků   MeSH
• potkani Wistar MeSH
• retikulocyty účinky léků   metabolismus   MeSH
• spotřeba kyslíku účinky léků   fyziologie   MeSH
• vazodilatancia farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenosindifosfát MeSH
• adenosinmonofosfát MeSH
• adenosintrifosfát MeSH
• donory oxidu dusnatého MeSH
• isosorbiddinitrát MeSH
• oxid dusnatý MeSH
• vazodilatancia MeSH

Bioptic samples from the vastus lateralis muscle were analyzed in a group of Czechoslovak representatives in the Nordic combination (ski-jumping and 15 km cross-country skiing). The distribution of individual muscle fibre types (FG, FOG and SO) was detected and correlated with values obtained by motor and functional performance tests. Histochemical analysis of the bioptic samples revealed a considerably heterogeneous distribution of muscle fibre types in the group studied. No typical profilation for this sport discipline was found. Weak correlation between the proportion of fast muscle fibres and explosive strength parameters was ascertained. The correlation between the proportion of slow muscle fibres and the capacity of O2 utilization (VO2max) was statistically significant. Strong correlation between the proportion of fast twitch fibres and relative maximal strength of knee extensors (N/kg) was disclosed. A non-linear relation between the area of fast twitch fibres and vigour of take-off was found.

• MeSH
• biopsie MeSH
• dospělí MeSH
• fyzická vytrvalost fyziologie   MeSH
• glykolýza fyziologie   MeSH
• histocytochemie MeSH
• isometrická kontrakce fyziologie   MeSH
• kosterní svaly cytologie   metabolismus   fyziologie   MeSH
• lidé MeSH
• lyžování * MeSH
• spotřeba kyslíku fyziologie   MeSH
• svalová vlákna typu I metabolismus   fyziologie   ultrastruktura   MeSH
• svalová vlákna typu II metabolismus   fyziologie   ultrastruktura   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• acidóza metabolismus   MeSH
• erytrocyty * MeSH
• glukosa-6-fosfatasa metabolismus   MeSH
• glykolýza fyziologie   MeSH
• koncentrace vodíkových iontů * MeSH
• laktáty metabolismus   MeSH
• lidé MeSH
• pyruváty metabolismus   MeSH
• techniky in vitro MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukosa-6-fosfatasa MeSH
• laktáty MeSH
• pyruváty MeSH

• MeSH
• glykolýza fyziologie   MeSH
• krysa rodu Rattus MeSH
• mozková kůra metabolismus   MeSH
• nucleus caudatus metabolismus   MeSH
• oxymetrie MeSH
• polarografie MeSH
• šířící se kortikální deprese fyziologie   MeSH
• spotřeba kyslíku * MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH