STUDIES ON THE RELATIONSHIP BETWEEN OXYGEN CONSUMPTION AND NITROGEN METABOLISM. III. IN POLYCYTHEMIA VERA.
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Journal Article↗
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[Effect of muscular activity on their consumption of nitrogen containing substances].
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Biological Phenomena↗
Whole body leucine metabolism in adolescents with Crohn's disease and growth failure during nutritional supplementation.
The adaptive response of whole body leucine metabolism to nutritional supplementation was determined in 6 adolescents with Crohn's disease and growth failure. Five healthy adolescents served as controls for body composition studies. In the first study period, all subjects received a constant diet comparable to usual intakes. In the second period, the patients were given overnight intragastric supplemental feedings that increased dietary protein and energy intakes approximately 40% (to 3.2 g/kg . day and 96 kcal/kg . day, respectively). During each dietary period, O2 consumption, nitrogen balance, whole body potassium (40K), and urinary creatinine measurements were obtained on all adolescents, and the patients received a primed, constant, intravenous infusion of [13C]leucine for 4 h in the fed state. Plasma leucine and expired carbon dioxide 13C-enrichments were determined by mass spectrometric techniques. In the first study, O2 consumption and nitrogen balances were similar between groups; in patients, 40K and urinary creatinine were reduced by 30% and 36%, respectively. With nutritional supplementation, nitrogen balance increased fourfold; O2 consumption and 40K increased by 32% and 10%, respectively. Similarly, whole body leucine flux increased from 166.9 +/- 5.9 to 201.3 +/- 11.2 mumol/kg . h (p less than 0.05) due to a 66% increase in leucine incorporation into body protein (p less than 0.01) and a 41% decrease in leucine oxidation (p less than 0.05). Thus, these studies demonstrate that the mechanisms responsible for lean body mass accretion during nutritional supplementation in adolescents with Crohn's disease and growth failure are increased rates of amino acid incorporation into body protein (via protein synthesis) and decreased rates of amino acid oxidation.
Adolescent↗
Effect of sepsis syndrome on neonatal protein and energy metabolism.
OBJECTIVE: It was our hypothesis that septic illness would alter both protein and energy metabolism in neonates, with elevations of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-1 beta (IL-1 beta) serving as markers for these effects. STUDY DESIGN: A total of 31 infants with suspected sepsis were enrolled into four groups: septic, sick-nonseptic, healthy-nonseptic, and recovered septic infants. Degree of illness, oxygen consumption, nitrogen balance, urine 3-methylhistidine/creatinine (MeH/Cr), and TNF-alpha, IL-6, IL-1 beta, and C-reactive protein (CRP) were measured. RESULTS: Oxygen consumption increased, while nitrogen balance decreased and MeH/Cr increased with increasing degree of illness. Nitrogen balance improved on recovery from sepsis. IL-6 and CRP levels were elevated in septic infants compared with sick-nonseptic and healthy infants. CONCLUSION: Neonates experience a hypermetabolic response with increased nitrogen loss during septic illness, proportional to the degree of illness. Increased delivery of protein substrate may be nutritionally advantageous to the septic neonate.
Cytokines↗
Monoxenic liquid culture of the entomopathogenic nematode Steinernema carpocapsae using a culture medium containing whey kinetics and modeling.
The submerged culture of the entomopathogenic nematode Steinernema carpocapsae and its symbiotic bacterium, Xenorhabdus nematophila, was carried out in orbitally agitated bottles using a culture medium containing whey (in grams per litre: 500 whey, 20 yeast extract, 10 dried egg yolk-food grade, 3 sodium chloride, 37 corn oil-food grade). Maximum total viable nematode concentrations of 198,333ml(-1) were achieved within fermentations of 24 days with 64% of the nematode population within the infective juvenile stage (IJ) (126,666ml(-1)) at the end. The kinetics of the bioprocess was well modelled using the four-parameter Sigmoidal model and the corresponding maximum specific rates of nematode production (0.47 day(-1)), carbohydrates consumption (0.0008g(carbohydrates)g(nematodes)(-1)day(-1)) and nitrogen consumption (4.44g(nitrogen)g(nematodes)(-1)day(-1)) are first proposed. Besides, X. nematophila appears to have the capacity of lactose hydrolysis.
Animals↗
Application of mass and energy balance regularities in fermentation. Reprinted from Biotechnology and Bioengineering, Vol. XX, No. 10, Pages 1595-1621 (1978).
Material and energy balances for fermentation processes are developed based on the facts that the heat of reaction per electron transferred to oxygen for a wide variety of organic molecules, the number of available electrons per carbon atom in biomass, and the weight fraction carbon in biomass are relatively constant. Mass-energy balance equations are developed which relate the biomass energetic yield coefficient to sets of variables which may be determined experimentally. Organic substrate consumption, biomass production, oxygen consumption, carbon dioxide production, heat evolution, and nitrogen consumption are considered as measured variables. Application of the balances using direct and indirect methods of yield coefficient estimation is illustrated using experimental results from the literature. Product formation is included in the balance equations and the effect of product formation on biomass yield estimates is examined. Application of mass-energy balances in the optimal operation of continuous single-cell protein production facilities is examined, and the variation of optimal operating conditions with changes in yield are illustrated for methanol as organic substrate.
Electrons↗
Oenococcus oeni preference for peptides: qualitative and quantitative analysis of nitrogen assimilation.
Optimization of malolactic fermentation in wine depends mainly on better understanding of nitrogen nutritional requirements of Oenococcus oeni. Four widely used starter strains and the reference ATCC BAA-1163 strain were grown in media containing different N sources: free amino acids, oligopeptides (0.5-10 kDa) or polypeptides (> 10 kDa). Amino acid auxotrophies were determined by the single omission technique. The tested strains were indifferent to only two to four amino acids and two of the starter strains appeared to be particularly demanding. Nitrogen consumption was investigated and a significant level of nitrogen was consumed by O. oeni only in the free amino acid medium. In media containing complex nitrogen sources, a global balance above 5 mg N l(-1) was enough to ensure biomass formation of all tested strains. Moreover, for all strains, bacterial growth yield was higher in the presence of nitrogen from peptides than that from free amino acids. However, no direct relationship between the bacterial growth level and the amount of nitrogen metabolized could be established. These findings were discussed in relation to the physiology of wine malolactic bacteria.
Amino Acids↗
Comparison of the metabolic effects of continuous postoperative enteral feeding and feeding at night only.
The effects of two different feeding patterns on oxygen consumption, nitrogen balance, blood biochemistry, and urinary catecholamine excretion were investigated over 5 d in patients after major head and neck surgery. Both groups of nine patients each were fed a regimen that provided 4.7 MJ on day 1 and 10 MJ on days 2-5 via a nasogastric tube by continuous infusion with an enteral feeding pump. One group was fed continuously for 24 h, the other was fed only at night, ie, from 1700 to 0900 the next morning. Oxygen consumption was significantly higher (P less than 0.01), nitrogen balance better (P less than 0.05), and urinary catecholamine excretion higher (P less than 0.05) in the 24-h-fed patients than in the night-fed patients. Postoperatively, feeding at night only is more energy efficient than is feeding continuously for 24 h, but is associated with poorer nitrogen balance. These differences may be mediated by sympathoadrenal mechanisms.
Adenocarcinoma↗
The ontogeny of physiological response to temperature in early stage spiny lobster (Jasus edwardsii) larvae.
The physiological response to temperature, in terms of oxygen consumption, nitrogen excretion and feed intake was examined in Jasus edwardsii larvae at mid-stages I-III. From stage I to stage III, the mass-specific oxygen consumption increased in a sigmoid pattern over the temperature range of 10-22 degrees C. The Q(10) value declined significantly from 14-18 to 18-22 degrees C range, indicating a reduced temperature dependence of larval metabolism at higher temperatures. At all stages, feed intake increased with increasing temperature but reached a plateau at the higher temperatures for stages I and II larvae. In contrast, nitrogen excretion increased linearly over this temperature range for all larval stages. Therefore, higher temperatures ( approximately 22 degrees C) may cause an energetic imbalance and reduce growth potential in early stage larvae. While the convection requirement index (quotient of feed intake and oxygen consumption) indicated an equivalent metabolic feeding efficiency from 14 to 22 degrees C, a consistent decline of the O/N ratio above 16-18 degrees C from stage I to stage III suggested that exposure to elevated temperatures may result in an increase in the amount of protein being diverted from growth to catabolic processes. Based on these results, a temperature of 18 degrees C is recommended for the culture of early stage J. edwardsii larvae.
Animals↗
The vinification of partially dried grapes: a comparative fermentation study of Saccharomyces cerevisiae strains under high sugar stress.
AIMS: The study of the fermentation performance of Saccharomyces cerevisiae strains under high sugar stress during the vinification of partially dried grapes. METHODS AND RESULTS: Microvinification of partially dried grape must with sugar concentration of 35 degrees Brix was performed using four commercial strains to carry out alcoholic fermentation. A traditional red vinification without nutrients addition was applied. Yeasts displayed different efficiency to convert sugar in ethanol and varied in glycerol yield. Sugar consumption and ethanol level were attested at 80-87% and 143.5-158.0 g l(-1) respectively. High correlation between sugar and assimilable nitrogen consumption rate was observed. Statistical treatment of data by principal component analysis highlighted the different behaviours that strains exhibited in regard to the production of higher alcohols and other compounds important to wine quality. CONCLUSIONS: Saccharomyces cerevisiae strains displayed appreciable capability to overcome osmotic stress and to yield ethanol fermenting high sugar concentration grape must in winemaking condition. SIGNIFICANCE AND IMPACT OF THE STUDY: The results provided insights on the strain contribution to wine quality subordinate to stress condition. This investigation is of applicative interest for winemaking and processing industry that use high sugar concentration musts.
Carbohydrate Metabolism↗
Heterotrophic production of biomass and lutein by Chlorella protothecoides on various nitrogen sources.
The effects of nitrate, ammonium, and urea as nitrogen sources on the heterotrophic growth of Chlorella protothecoides were investigated using flask cultures. No appreciable inhibitory effect on the algal growth was observed over a nitrogen concentration range of 0.85-1.7 g l(-)(1). In contrast, differences in specific growth rate and biomass production were found among the cultures with the various nitrogen compounds. The influence of different nitrogen sources at a concentration equivalent to 1.7 g l(-)(1) nitrogen on the heterotrophic production of biomass and lutein by C. protothecoides was investigated using the culture medium containing 40 g l(-)(1) glucose as the sole carbon and energy source in fermentors. The maximum biomass concentrations in the three cultures with nitrate, ammonium, and urea were 18.4, 18.9, and 19.6 g l(-)(1) dry cells, respectively. The maximum lutein yields in these cultures were between 68.42 and 83.81 mg l(-)(1). The highest yields of both biomass and lutein were achieved in the culture with urea. It was therefore concluded that urea was the best nitrogen source for the production of biomass and lutein. Based on the experimental results, a group of kinetic models describing cell growth, lutein production, and glucose and nitrogen consumption were proposed and a satisfactory fit was found between the experimental results and predicted values. Dynamic analysis of models demonstrated that enhancing initial nitrogen concentration in fermentor cultures, which correspondingly enhances cell growth and lutein formation, may shorten the fermentation cycle by 25-46%.
Journal Article↗
Effects of starvation on oxygen consumption, ammonia excretion and biochemical composition of the hepatopancreas on adult males of the False Southern King crab Paralomis granulosa (Crustacea, Decapoda).
Adults of the False Southern King crab, Paralomis granulosa, were starved between 0 and 12 days to evaluate the impact of fasting on the oxygen consumption, nitrogen excretion, O/N ratio and changes on biochemical composition of the hepatopancreas. During the experiment, no mortalities were recorded; physiological changes were detected after 6 days of fasting with an increase of nitrogen excretion (p<0.05). After 9 days of starvation, the crabs showed a maximum decrease in the lipid content (4.3+/-1.2%, p<0.05), accompanied by an increase in oxygen consumption (53.1+/-10.9 microg O2 h(-1) g(-1)). The lowest O/N ratio was detected after 6 days (6.4+/-4.8) and the highest after 12 days of fasting (38.1+/-20.4), indicating that initially crabs utilized proteins as source of energy , followed by lipids. Moreover, after 12 days, there was a significant increase in the hepatosomatic index (HI) and total lipid content (9.7+/-1.0%, p<0.05), which could be associated with the re-absorption of other tissues to the hepatopancreas. Our results provide new information on this species that shows a different pattern of adaptation for each period of starvation and a good correlation between physiological and biochemical parameters. The ability to withstand and recover from periods of nutritional stress is an important adaptation for survival of any organism that must sporadically endure periods of limited food supply.
Ammonia↗
Influence of nutritional status on the daily patterns of nitrogen excretion in the carp (Cyprinus carpio L.) and the rainbow trout (Salmo gairdneri R.).
Nitrogen (ammonia and/or urea) excretion in carp and rainbow trout kept under different feeding regimes was continuously monitored over 24-hr cycles. The daily nitrogen excretion patterns resulting from these feeding regimes were studied over several days after a change from one made to another. Constant levels of endogenous nitrogen excretion were reached about one week after the start of a fasting period; almost one week was needed for the daily nitrogen excretion pattern to stabilize after the feeding rhythm was changed. Overall daily nitrogen excretion rates were directly related to nitrogen consumption in carp as well as in trout. The rate of ammonia excretion increased immediately after each meal; the maximum rate occurred at different intervals, depending on the amount of nitrogen intake as well as on the time-lapse after a particular feeding regime was initiated. Contrary to data on sockeye salmon, post-digestive nitrogen excretion rate was distinctly different from the ENE rates observed during fasting in carp and rainbow trout.
Ammonia↗
Effect of spinal cord stimulation on myocardial blood flow assessed by positron emission tomography in patients with refractory angina pectoris.
Spinal cord stimulation in angina pectoris increases exercise capacity and reduces both anginal attacks and ischemic electrocardiographic signs. This suggests an anti-ischemic action, perhaps through changes in myocardial blood flow. In 9 patients, regional myocardial blood flow was studied with positron emission tomography before and after 6 weeks of spinal cord stimulation, both at rest and during a dipyridamole stress test. Frequency of anginal attacks and consumption of short-acting nitrates were assessed by patient diaries. Exercise duration and time to angina were measured with treadmill exercise tests. After 6 weeks of stimulation, both frequency of daily anginal attacks and nitrogen consumption decreased (3.7 +/- 1.7 vs 1.4 +/- 1.0 [p <0.01] and 2.8 +/- 2.2 vs 1.1 +/- 1.2 tablets [p = 0.01], respectively); exercise duration and time to angina increased (358 +/- 165 vs 493 +/- 225 seconds [p <0.01] and 215 +/- 115 vs 349 +/- 213 seconds [p = 0.02], respectively); and ST-segment depression during dipyridamole stress testing was reduced (0.17 [0 to 0.5] mV vs 0.09 [0 to 0.2] mV, p = 0.04) (all data mean +/- SD). Total resting blood flow remained unchanged (115 +/- 29 vs 127 +/- 31 ml/min/100 g, p = 0.31), but flow reserve decreased (146 +/- 43% vs 122 +/- 39%, p = 0.04). The coefficient of variation of flow, representing flow heterogeneity, decreased after treatment, both at rest (20.1 +/- 3.8% vs 17.4 +/- 2.6%, p = 0.04) and after dipyridamole stress (26.2 +/- 4.4% vs 22.9 +/- 5.5%, p = 0.02). Thus, spinal cord stimulation is clinically effective due to homogenization of myocardial blood flow. Since flow reserve decreases despite clinical improvement, the dipyridamole effect may be blunted by spinal cord stimulation.
Angina Pectoris↗
Does oral rehydration therapy alter food consumption and absorption of nutrients in children with cholera?
In order to estimate consumption of food and absorption of nutrients, a metabolic balance study was conducted in 47 children between 1 and 5 years old, suffering from acute cholera. Twenty-two of the children were treated by intravenous solution (IV) only and 25 others by oral rehydration along with intravenous solution (ORS/IV) when necessary. After initial rehydration a nonabsorbable charcoal marker was fed to the patients followed by a typical Bangladeshi home food of known composition offered ad libitum. Appearance of the first marker in the faeces was taken as zero hour (0 h); at 72 h a second marker was fed. Faeces, urine and vomitus were collected up to the appearance of the second marker. Intake of IV fluid, ORS and any other fluid or food were recorded accurately. Samples of faeces, urine and vomitus were analysed for energy, fat and nitrogen. Consumption of nutrients and absorption in both groups were calculated. There was no significant difference in the intake or absorption of energy or carbohydrate between the two groups. The consumption of fat and protein was slightly, but significantly, lower in the ORS/IV group during the acute stage of diarrhoea than in the IV group. Absorption of nitrogen was significantly lower in the ORS/IV group, but absorption of fat was not significantly impaired. Vomiting was significantly higher in the ORS/IV group. The differences in the consumption and absorption of nutrients between the two groups were transient and came to the same level within 2 weeks after recovery.
Bangladesh↗
The influence of operational conditions in sequencing batch reactors on removal of nitrogen and organics from municipal landfill leachate.
The removal of nitrogen and organics from municipal landfill leachate in sequencing batch reactors (SBR) was investigated in the present study. The influence of hydraulic retention time (HRT), sludge age, manner of leachate dosage (short filling period of SBR and filling during the reaction period), and operational conditions with and without a mixing phase in the SBR cycle was explored. Four series were performed. In each series, the HRT used in the four SBRs was 12, 6, 3 and 2 days, respectively. Series 1 and 2 were characterized by a short leachate filling period, whereas series 3 and 4 were characterized by filling during the 4 h duration of the reaction in the SBR cycle. In series 1-3 SBR reactors worked with mixing and aeration phases, whereas in series 4 they worked only with an aeration phase. The effectiveness of the removal of organics increased with the extension of the HRT of leachate, particularly under operational conditions with the mixing and aeration phases in the SBR cycle. At 12 days HRT, the SBRs with the mixing and aeration phases in the cycle (series 1-3) showed better results than those with only an aeration phase (series 4). However, at 2 days HRT the operational conditions in SBR reactors with leachate filling over the reaction period (series 3 and 4) were more suitable. The highest efficiency of ammonium removal was obtained in series 1 with a short leachate filling period. In this series, at an HRT of 3-12 days, the ammonium concentration in the effluent did not exceed 1 mg NNH4 L(-1). Nitrogen removal proceeded mainly in the aeration phase as a result of ammonium losses and, to a lesser extent, dissimilative nitrate reduction over the mixing phase. The highest percentage of nitrogen removal as a result of ammonium losses was observed in series with a short filling period and long sludge age (series 1) and also in series without a mixing phase and filling over the aeration phase (series 4), whereas the highest nitrogen consumption for biomass production occurred in series 3 with filling during the reaction period and mixing phase of the cycle.
Biomass↗
Effects of the horn fly (Diptera: Muscidae) on physiological and nutritional responses of beef steers: continuous fly population levels.
Twenty-four Hereford-Angus crossbred beef steers were exposed to 0, 75, 150, and 225 horn flies, Haematobia irritans (L.), per head under controlled environmental conditions. The physiological and nutritional indices of all steers were recorded during a 14-d infestation period. Overall rectal temperature increased in steers exposed to 225 H. irritans was per head. Feed intake and nitrogen consumption by steers exposed to 225 H. irritans was lower than uninfested steers during the first 4 d. Overall serum cortisol was lower in steers exposed to 150 or 225 H. irritans per head compared with unexposed steers. Compared with unexposed steers, packed cell volume (percentage) was lower in steers exposed to 150 H. irritans on days 4, 7, and 14, lower in steers exposed to 225 H. irritans on days 7 and 14, and lower in steers exposed to 75 H. irritans on day 14. Blood urea nitrogen (BUN) was higher on day 1 in steers exposed to 75 H. irritans per head compared with uninfested steers, whereas BUN was lower in 225 H. irritans-exposed steers on days 7, 10, and 14 when compared with uninfested steers. Our data, in conjunction with previously published data, suggest that rectal temperature increases in beef steers exposed to > 150 H. irritans per head, and water consumption and urine production increases at infestation levels > 225 H. irritans per per head. Our data were unable to resolve H. irritans effects on steer heart rate, respiration rate, urinary nitrogen excreted, nitrogen retained, and serum cortisol levels.
Animal Nutritional Physiological Phenomena↗
[Concept of labile protein and the adaptation of nitrogen metabolism in protein deficiency in man].
Investigations involving 30 healthy males, who for 45 days consumed standard semisynthetic diets differing in the caseine content (from 0 to 15.1 g of nitrogen per day) and serving as a sole source of protein, furnished data on the nitrogen excretion kinetics and nitrogen balance. Mathematical analysis of these data allowed it to find the existence of general regularity in the nitrogen excretion and to deduce an integral equation of its losses at different levels of nitrogen consumption. Pertinent calculations have ascertained that by the labile protein one should understand not the specific proportion of the total protein in the organism, but the actual rate of its metabolism, manifesting itself in the routine lag-phase during adaptation of the nitrogen metabolism to a new level of the protein allowances in the organism. The data thus made available permitted it, at the same time, to propose a criterion for estimating the optimal requirements of man in proteins.
Adaptation, Physiological↗