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2. Correlation between metabolic depression and ecdysteroid peak during embryogenesis of the desert locust, Schistocerca gregaria (Orthoptera: Acrididae)
- Creator:
- Sláma, Karel
- Type:
- article, model:article, and TEXT
- Subject:
- Acrididae, Schistocerca gregaria, ecdysteroids, oxygen consumption, morphogenesis, metamorphosis, embryogenesis, respiratory metabolism, and pharate stages
- Language:
- English
- Description:
- Respiratory metabolism of developing eggs of Schistocerca gregaria has been individually monitored by means of scanning microrespirography. The freshly oviposited eggs consumed 7 nl of O2 /min./egg (50 µl O2/g/h) while the pharate 1st instar larvae shortly before hatching consumed 141 nl of O2/min./egg (550 µl O2/g/h), which shows 20-fold metabolic increase during the egg stage. The output of CO2 was also regular, without discontinuous bursts throughout the whole embryonic development. The amounts of CO2 produced were constantly close to R.Q. ratio of 0.7, suggesting that lipid was the main energetic source. The vermiform, pharate 1st instar larvae emerging from the eggs exhibited very high respiratory rates (up to 3,000 µl O2/g/h). During initial phases of the egg stage, O2 consumption steadily increased until day 6, which was associated with katatrepsis or blastokinesis stage of the embryo (61 nl of O2/egg/min. = 240 µl O2/g/h). Since blastokinesis, respiratory metabolism of the egg remained constant or decreased steadily until day 10, when it rose sharply again towards hatching. The temporary metabolic depression was closely correlated with endogenous peak in ecdysteroid concentration within the embryo. These results corroborate validity of the reciprocal, high ecdysteroid - low metabolism rule previously known from insect metamorphosis. They extend its application into the period of embryogenesis. Practical implications of certain physiological, morphological and evolutionary consequences of these findings are discussed with special emphasis on the connecting links between embryogenesis and metamorphosis.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
3. Effect of captopril on serum lipid levels and cardiac mitochondrial oxygen consumption in experimentally-induced hypercholesterolemia in rabbits
- Creator:
- Kojic, Z., Gopcevic, K., Dragoslav Marinković, and Tasic, G.
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, mitochondrie, srdce, hypercholesterolémie, králíci, mitochondrias, heart, hypercholesterolemia, rabbits, ACE inhibitors, oxygen consumption, 14, and 612
- Language:
- English
- Description:
- Angiotensin converting enzyme inhibitors are widely used in therapy of cardiovascular diseas es. However, the consensus on effects of these inhibitors in control of myocardial oxygen consumption during the process of experimental hypercholesterolemia and under the condition of endothelial dysfunction has not been reached. Here we examined effects of captopril, an angiotensin converting enzyme inhibitor, on serum lipid levels and oxygen consumption rate in mitochondria isolated from heart of rabbits treated by hypercholesterolemic diet. During the twelve-week period, th e Chinchilla male rabbits were daily treated by saline (controls); 1 % cholesterol diet; 5 mg/kg/day captopril or 1 % cholesterol + 5 mg/kg/day captopril. Total- and high-densi ty lipoprotein cholesterol and triglyceride in serum were measured spectrophotometricly. The left ventricle mitochondrial fraction was isolated and myocardial oxygen consumption was measur ed by Biological Oxygen Monitor. Mitochondria isolated from hearts of rabbits exposed to hypercholesterolemic diet sh owed significantly reduced respiration rates (state 3 and state 4) with altering adenosine diphosphate/oxygen ratio, whereas the respiratory control ratio was not affected when compared to controls. Mitochondria from cholesterol/captopril-treated animals showed significantly reduced respiration rates without altering adenosine diphosphate/oxygen ratio index or respiratory control ratio. Although captopril did not exert the favorable effect on serum lipid levels in cholesterol-treated animals, it restored the mitochondrial oxygen consumption. Further studies should be performed to define the under lying physiological and/or pathophysiological mechanisms and clinical implications., Z. Kojic ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Metabolic costs of hybridization in newts
- Creator:
- Gvoždík, Lumír
- Type:
- article, model:article, and TEXT
- Subject:
- oxygen consumption, energetic metabolism, hybrids, Triturus, amphibians, mitonuclear interactions, and reproductive barriers
- Language:
- English
- Description:
- Heterospecific hybrids often suffer from a lowered fitness relative to parental species. Contextdependent intrinsic costs of hybridization are partially due to a malfunction in cell biochemical machinery that affects metabolic rates at the organismal level. This study examines whether heterospecific hybridization influences the metabolic costs of maintenance in F1 hybrids between closely related newts, Triturus carnifex and T. dobrogicus. When controlled for body size, oxygen consumption in hybrid newts was 59-76 % higher than in the parental species. This suggests that high standard metabolic rates in hybrids may contribute to thecosts of hybridization in newts.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5. Physiological response to whole-body vibration in athletes and sedentary subjects
- Creator:
- Gojanovic, B., Feihl, F., Gremion, G., and Waeber, B.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, tělesná cvičení, srdeční rytmus, vibrace, exercises, heart rate, vibration, oxygen consumption, sedentary lifestyle, 14, and 612
- Language:
- English
- Description:
- Whole-body vibration (WBV) is a new exercise method, with good acceptance among sedentary subjects. The metabolic response to WBV has not been well documented. Three groups of male subjects, inactive (SED), endurance (END) and strength trained (SPRINT) underwent a session of side-alternating WBV composed of three 3-min exercises (isometric half-squat, dynamic squat, dynamic squat with added load), and repeated at three frequencies (20, 26 and 32 Hz). VO2, heart rate and Borg scale were monitored. Twenty-seven healthy young subjects (10 SED, 8 SPRINT and 9 END) were included. When expressed in % of their maximal value recorded in a treadmill test, both the peak oxygen consumption (VO2) and heart rate (HR) attained during WBV were greatest in the SED, compared to the other two groups (VO2: 59.3 % in SED vs 50.8 % in SPRINT and 48.0 % in END, p<0.01; HR 82.7 % in SED vs 80.4 % in SPRINT and 72.4 % in END, p<0.05). In conclusions, the heart rate and metabolic response to WBV differs according to fitness level and type, exercise type and vibration frequency. In SED, WBV can elicit sufficient cardiovascular response to benefit overall fitness and thus be a potentially useful modality for the reduction of cardiovascular risk., B. Gojanovic, F. Feihl, G. Gremion, B. Waeber., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6. Procedural memory trace for increased tidal volume can be demonstrated in healthy volunteers
- Creator:
- Šmejkal, V., Radvanský, J., and Matouš, M.
- Type:
- article, model:article, and TEXT
- Subject:
- tidal volume, hyperventilation, respiratory work, oxygen consumption, and procedural memory
- Language:
- English
- Description:
- The minority of healthy subjects can (without previous learning) breathe at exactly double of their resting tidal volume on demand. The aim of the present study was to find whether this estimate of tidal volume value can be learned and at what speed. Basic spirometric values were measured by Oxycon B in 20 healthy volunteers. They learned in one day to breathe at double of the resting tidal volume twice for 3 min. The existence and duration of the memory trace was ascertained four times (three times on the same day, once three weeks later). This engram can be demonstrated on the day of learning after 1 or 2 trials of 3 min each. Three weeks later the memory trace is weak but still present. This fact means that a new breathing pattern can be learned. During learning and tests the subjects hyperventilate but no correlation was seen between learning ability and intensity of hyperventilation.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7. Proton concentration in the thylakoid membranes can regulate energy distribution between the two photosystems
- Creator:
- Tongra, T., Bharti, S., and Jajoo, A.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, špenát, photosynthesis, light-harvesting complex, luminal pH, nonphotochemical quenching, oxygen consumption, oxygen evolution, spinach, 2, and 581
- Language:
- Multiple languages
- Description:
- The aim of our study was to investigate the role of protons in regulating energy distribution between the two photosystems in the thylakoid membranes. Low pH-induced changes were monitored in the presence of a proton blocker, N,N′-dicyclohexylcarbodiimide (DCCD). When thylakoid membranes were suspended in a low-pH reaction mixture and incubated with DCCD, then a decrease in the fluorescence intensity of photosystem II (PSII) was observed, while no change in the intensity of photosystem I (PSI) fluorescence occurred according to the measured fluorescence emission spectra at 77 K. Since low pH induced distribution of energy from PSII to PSI was inhibited in the presence of DCCD, we concluded that pH/proton concentration of the thylakoid membranes plays an important role in regulating the distribution of the absorbed excitation energy between both photosystems., T. Tongra, S. Bharti, A. Jajoo., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8. Remote ischemic preconditioning of the heart: protective responses in functional and biophysical properties of cardiac mitochondria
- Creator:
- Miroslav Ferko, Kancirová, I., Jašová, M., Slávka Čarnická, Muráriková, M., Waczulíková, I., Sumbalová, Z., Jarmila Kucharská, Oľga Uličná, Ravingerová, T., and Atila Ziegelhöffer
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, ischemie, mitochondrie, ischemia, mitochondrias, rat heart, remote preconditioning, reperfusion injury, heart mitochondria, oxygen consumption, respiratory chain, mitochondrial membrane fluidity, 14, and 612
- Language:
- English
- Description:
- Remote ischemic preconditioning (RIP)-induced protection of myocardial energetics was well documented on the level of tissue, but data concerning the involvement of mitochondria were missing. We aimed at the identification of changes in membrane properties and respiratory functions induced in rat heart mitochondria by RIP. Experiments were performed on 46 male Wistar rats divided into control and RIP-treated groups of 21 animals each. Blood flow in the occluded area was recorded by MRI angiography in four animals. RIP protocol comprised of three successive 5-min occlusions each followed by 5-min reperfusions of descending branches of the right hind limb femoral artery. The efficacy of RIP was evaluated as the extent of RIP-induced protection against damage to the functions of mitochondria isolated by differential centrifugation after 30-min global ischemia followed by 40-min reperfusion of the hearts in Langendorff mode. Assessments: mitochondrial membrane fluidity with a fluorescent probe DPH, CoQ9 and CoQ10 with HPLC, mitochondrial respiration with the Oxygraph-2k (Oroboros). Results revealed that RIP was affecting the mitochondria. The immediate protection conferred by RIP involves beneficial and prognostically significant effects: a total elimination of ischemia/reperfusion-induced depression of mitochondrial membrane fluidity and a trend for better preservation of mitochondrial state 3 respiration., M. Ferko, I. Kancirová, M. Jašová, S. Čarnická, M. Muráriková, I. Waczulíková, Z. Sumbalová, J. Kucharská, O. uličná, T. Ravingerová, A. Ziegelhöffer., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9. Variability of mitochondrial respiration in relation to sepsis-induced multiple organ dysfunction
- Creator:
- Kohoutová, M., Dejmek, J., Tůma, Z., and Kuncová, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- sepsis, mitochondria, oxygen consumption, multiple organ dysfunction, and animal models
- Language:
- English
- Description:
- Ample experimental evidence suggests that sepsis could interfere with any mitochondrial function; however, the true role of mitochondrial dysfunction in the pathogenesis of sepsis-induced multiple organ dysfunction is still a matter of controversy. This review is primarily focused on mitochondrial oxygen consumption in various animal models of sepsis in relation to human disease and potential sources of variability in experimental results documenting decrease, increase or no change in mitochondrial respiration in various organs and species. To date, at least three possible explanations of sepsis-associated dysfunction of the mitochondrial respiratory system and consequently impaired energy production have been suggested: 1. Mitochondrial dysfunction is secondary to tissue hypoxia. 2. Mitochondria are challenged by various toxins or mediators of inflammation that impair oxygen utilization (cytopathic hypoxia). 3. Compromised mitochondrial respiration could be an active measure of survival strategy resembling stunning or hibernation. To reveal the true role of mitochondria in sepsis, sources of variability of experimental results based on animal species, models of sepsis, organs studied, or analytical approaches should be identified and minimized by the use of appropriate experimental models resembling human sepsis, wider use of larger animal species in preclinical studies, more detailed mapping of interspecies differences and organ-specific features of oxygen utilization in addition to use of complex and standardized protocols evaluating mitochondrial respiration.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public