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PubMed1978

Microbial fixation of nitrogen in presence of lanthanum sulphate with sodium molybdate.

The effect of lanthanum sulphate together with 100 micrometer of sodium molybdate show that there is considerable increase in nitrogen fixation and carbon consumption in the culture medium of nitrogen-fixing Azotobacter species A1 and A2, isolated from Allahabad soil. But these combination decrease the nitrogen fixation and carbon consumption in case of another species, Azotobacter A3, of the same soil.

Azotobacter↗
PubMed1991

Influence of the feeding frequency on nutrient utilization in man: consequences for energy metabolism.

A study was conducted to investigate whether there is a diurnal pattern of nutrient utilization in man and how this is affected by meal frequency to explain possible consequences of meal frequency for body weight regulation. When the daily energy intake is consumed in a small number of large meals, there is an increased chance to become overweight, possibly by an elevated lipogenesis (fat synthesis and accumulation) or storage of energy after the meal. Thirteen subjects, two males and eleven females, were fed to energy balance in two meals per day (gorging pattern) and seven meals per day (nibbling pattern) over 2-day intervals. On the second day on each feeding regimen, the diurnal pattern of nutrient utilization was calculated from simultaneous measurements of oxygen consumption, carbon dioxide production and urinary nitrogen excretion over 3 h intervals in a respiration chamber. A gorging pattern of energy intake resulted in a stronger diurnal periodicity of nutrient utilization, compared to a nibbling pattern. However, there were no consequences for the total 24 h energy expenditure (24 h EE) of the two feeding patterns (5.57 +/- 0.16 kJ/min for the gorging pattern; 5.44 +/- 0.18 kJ/min for the nibbling pattern). Concerning the periodicity of nutrient utilization, protein oxidation during the day did not change between the two feeding patterns. In the gorging pattern, carbohydrate oxidation was significantly elevated during the interval following the first meal (ie from 1200 h to 1500 h, P less than 0.01) and the second meal (ie from 1800 h to 2100 h, P less than 0.05). The decreased rate of carbohydrate oxidation observed during the fasting period (from rising in the morning until the first meal at 1200 h), was compensated by an increased fat oxidation from 0900 to 1200 h to cover energy needs. In the nibbling pattern, carbohydrate and fat oxidation remained relatively constant during the active hours of the day.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2000

Production and consumption of nitric oxide by three methanotrophic bacteria.

We studied nitrogen oxide production and consumption by methanotrophs Methylobacter luteus (group I), Methylosinus trichosporium OB3b (group II), and an isolate from a hardwood swamp soil, here identified by 16S ribosomal DNA sequencing as Methylobacter sp. strain T20 (group I). All could consume nitric oxide (nitrogen monoxide, NO), and produce small amounts of nitrous oxide (N(2)O). Only Methylobacter strain T20 produced large amounts of NO (>250 parts per million by volume [ppmv] in the headspace) at specific activities of up to 2.0 x 10(-17) mol of NO cell(-1) day(-1), mostly after a culture became O(2) limited. Production of NO by strain T20 occurred mostly in nitrate-containing medium under anaerobic or nearly anaerobic conditions, was inhibited by chlorate, tungstate, and O(2), and required CH(4). Denitrification (methanol-supported N(2)O production from nitrate in the presence of acetylene) could not be detected and thus did not appear to be involved in the production of NO. Furthermore, cd(1) and Cu nitrite reductases, NO reductase, and N(2)O reductase could not be detected by PCR amplification of the nirS, nirK, norB, and nosZ genes, respectively. M. luteus and M. trichosporium produced some NO in ammonium-containing medium under aerobic conditions, likely as a result of methanotrophic nitrification and chemical decomposition of nitrite. For Methylobacter strain T20, arginine did not stimulate NO production under aerobiosis, suggesting that NO synthase was not involved. We conclude that strain T20 causes assimilatory reduction of nitrate to nitrite, which then decomposes chemically to NO. The production of NO by methanotrophs such as Methylobacter strain T20 could be of ecological significance in habitats near aerobic-anaerobic interfaces where fluctuating O(2) and nitrate availability occur.

Genes, rRNA↗
PubMed1984

[Effect of the composition of the diet on the excretion of 3-methylhistidine and creatinine in urine].

3-Methylhistidine in a defined amount of meat, consumed by 7 healthy persons is excreted quantitatively in the urine within 2 days. Simultaneously recorded creatinine excretion remained constant in 4 of the participants while in 3 cases a considerable increase was observed during the day of meat consumption. An increase in nitrogen excretion as a result of meat consumption was observed in 5 out of 7 persons.

Adult↗
PubMed1991

[Do the variations in water carbon dioxide pressure and PH have an effect on the nature of end products of protein catabolism, ammonia and urea, in the clawed frog Xenopus laevis?].

The effects of PCO2 and pH changes in the ambient water on the nitrogen catabolism and the proportions of the excreted nitrogenous end products, ammonia and urea, were studied in the clawed frog, Xenopus laevis, at 24 degrees C. In animals living in artificial fresh water, the exposure to a hypocapnic alkalosis (PCO2 = 0.7 Torr instead of 10 Torr) did not entail any change in the nitrogen catabolism. In animals who lived in a water loaded with NaCl and had therefore a higher oxygen consumption, an intense nitrogen catabolism and a marked ureotelism, the hypocapnic alkalosis seems to have increased the intensity of the nitrogen catabolism. In neither group were there signs of ammonia toxicity.

Ammonia↗
PubMed2005

High ambient ammonia promotes growth in a ureogenic goby, Mugilogobius abei.

Mugilogobius abei has the ability to produce large amounts of urea when exposed to high ambient ammonia. Despite this metabolically costly approach, and reports of growth inhibition effects of ammonia on fish, M. abei exposed to ammonia shows no adverse effects on growth. To investigate this observation the growth of M. abei was measured at room temperatures for 8 weeks at a constant ration level under solitary and grouped conditions, in 20% SW with or without (control) 2 mM NH(4)Cl. Furthermore, pituitary mRNA levels of growth hormone, oxygen consumption, incorporation of external (15)N-ammonia into amino acid and protein fractions as well as behavioral activities were also examined. The specific growth rates of ammonia-exposed fish under grouped condition over the 8 weeks were significantly higher than those of control, while those rates under solitary condition were not significantly different between the treatments. The pituitary of ammonia-exposed fish had higher growth hormone mRNA than in control fish. The use of (15)N isotope revealed that M. abei can actively use external ammonia as a supplementary nitrogen source. Oxygen consumption of ammonia-exposed fish was significantly lower than that of control fish. Locomotor activity and aggressive behavior under grouped condition were significantly reduced in ammonia-exposed fish as compared to those of control. These combined alterations in the ammonia-exposed fish may result in the higher growth rates.

Amino Acids↗
PubMed1994

Inhibitory mechanisms of antibody production by nitrogen oxides released from activated macrophages during the immune response: relationship to energy consumption.

We investigated the relationship between the sensitivity of mouse splenocytes in immune response to nitrogen oxides and energy consumption rate of the cells. Macrophage-like cells (Mm1) pretreated with IL-6 served as the source of the nitrogen oxides. The antibody production of both 2,4,6-trinitrophenyl-keyhole limpet haemocyanin-primed splenocytes and B cell hybridomas was markedly reduced; about 20-40% of splenocytes and B cell hybridomas were killed by co-culture with IL-6-treated Mm1. Cell viability and antibody production were completely restored by the addition of NG-monomethyl L-arginine to the culture medium. The cytotoxicity of the nitrogen oxides was correlated with the distance between effector and target cells. Under conditions of low cytotoxicity, antibody production by B cell hybridomas was suppressed by the nitrogen oxides, this suppression not being correlated with the reduction in cell growth. The sensitivity of the target cells differed in co-cultures of antigen-primed splenocytes and B cell hybridomas with IL-6-treated Mm1. The nitric oxide-sensitivity of the cells corresponded to their 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reducing activity and ATP consumption rate. These findings suggest that nitrogen oxides act as regulatory molecules in immune response in three ways: cytostasis, reduction of cell growth and suppression of antibody synthesis.

Animals↗
PubMed1979

Effect of deficiencies of single essential amino acids on nitrogen and energy utilisation in chicks.

1. Diets 50% deficient in single essential amino acids were fed to chicks from day 8 to day 18 after hatching to evaluate body-weight gain, food consumption, body composition, nitrogen (N) and energy utilisation. 2. Body-weight gain was reduced most severely by deficiency of isoleucine followed in decreasing order by threonine, arginine, valine, histidine, tryptophan, methionine plus cystine, phenylalanine plus tyrosine, leucine and lysine, and possible reasons for the differences are discussed. 3. Body-weight gain and food efficiency were highly correlated with food consumption but metabolisable energy value of diets was not affected by single essential amino acid deficiencies. 4. Generally N retention (N retained/N consumed) and energy retention (energy retained/energy consumed) reflected food consumption, except for a lower N retention by chicks fed on the methionine plus cystine-deficient diet and for a lower energy retention by chicks fed on the valine deficient diet. 5. The amino acid deficient in the diet was present at very low concentration in the blood plasma.

Amino Acids, Essential↗
PubMed2004

Optimising design, operation and energy consumption of biological aerated filters (BAF) for nitrogen removal of municipal wastewater.

The Biofiltration process in wastewater treatment combines filtration and biological processes in one reactor. In Europe it is meanwhile an accepted technology in advanced wastewater treatment, whenever space is scarce and a virtually suspended solids-free effluent is demanded. Although more than 500 plants are in operation world-wide there is still a lack of published operational experiences to help planners and operators to identify potentials for optimisation, e.g. energy consumption or the vulnerability against peakloads. Examples from pilot trials are given how the nitrification and denitrification can be optimised. Nitrification can be quickly increased by adjusting DO content of the water. Furthermore carrier materials like zeolites can store surplus ammonia during peak loads and release afterwards. Pre-denitrification in biofilters is normally limited by the amount of easily degradable organic substrate, resulting in relatively high requirements for external carbon. The combination of pre-DN, N and post-DN filters is much more advisable for most municipal wastewaters, because the recycle rate can be reduced and external carbon can be saved. Exemplarily it is shown for a full scale preanoxic-DN/N/postanoxic-DN plant of 130,000 p.e. how 15% energy could be saved by optimising internal recycling and some control strategies.

Ammonia↗
PubMed1996

Respiratory gas exchange, nitrogenous waste excretion, and fuel usage during starvation in juvenile rainbow trout, Oncorhynchus mykiss.

Oxygen consumption, CO2 excretion, and nitrogenous waste excretion (75% ammonia-N and 25% urea-N) were measured daily in 4-g rainbow trout over a 15-day starvation period. Oxygen consumption and CO2 excretion declined while N excretion increased transiently in the mid-part of the starvation period but was unchanged from control levels at the end. Component losses (as percentage of total fuel used) of protein, lipid, and carbohydrate were 66.5, 31.1, and 2.4% respectively, as measured from changes in body weight and body composition, the latter relative to a control group at day 0. Instantaneous fuel use, as calculated from the respiratory quotients and nitrogen quotients, indicated that relative protein use rose during starvation, but contributed at most 24% of the aerobic fuel (as carbon). Lipid metabolism fell from about 68 to 37%, and was largely replaced by carbohydrate metabolism which rose from 20 to 37%. We conclude that the two approaches measure different processes, and that the instantaneous method is preferred for physiological studies. The compositional method is influenced by greater error, and measures the fuels depleted, not necessarily burned, because of possible interconversion and excretion of fuels.

Analysis of Variance↗
PubMed1984

[Effect of metabolism-oriented substrate administration on energy and protein metabolism in polytraumatized artificial respiration patients].

An adequate "individually tailored" infusion and nutritional therapy is one of the essential prerequisites for an optimal healing process - especially in ventilated, polytraumatized patients with reduced compensatory capacities. There are nevertheless practically no publications dealing with the effect of substrate application adjusted to the measured metabolic rate on the energy and protein metabolism of the critically ill. In order to clarify this situation a prospective study was carried out on a group of 40 polytraumatized, ventilated patients, who were randomized into four groups, each receiving different infusion and nutritional regimen. The O2-consumption, energy expenditure, nitrogen balance and substrate concentrations in plasma and urine were determined, and the urea production rate and substrate turnover of all patients calculated. In the groups given nutritional support carbohydrate application adjusted to O2-consumption - lead to blood glucose concentrations which were persistently high. However, median values did not exceed 10 mmol/l and insulin application was never necessary. Energy expenditure - calculated from O2-consumption - averaged about 3000 kcal/day and was clearly below values previously reported in the literature for patients comparable to those studied in this investigation. There was no difference in energy expenditure between the patients treated with various infusion regimen. In none of the groups the median plasma urea concentration did exceed reference range. Despite an apparent improvement in nitrogen retention rate - through an increased amino-acid intake and a balanced energy input - an increased urea production rate resulted. When a balanced delivery of energy-yielding substrates is given, 2 g amino-acids/kg/day seems to be the upper limit of nitrogen support in the critically ill. 3-methylhistidine excretion in urine was parallel to urea production rate, indicating that the amino-acid sparing effect of carbohydrates is mainly derived from amino-acid conservation in muscle. These results seem to indicate that even in the early posttraumatic period a substrate application, adjusted to the measured turnover is possible without leading to a disturbance in homeostasis.

Adolescent↗
PubMedDate not supplied

Respiratory peripheral chemosensory irritation, acute and repeated exposure toxicity studies with aerosols of triethylene glycol.

The potential for adverse effects from exposure to respirable aerosols of triethylene glycol (TEG: CAS Number 112-27-6) was investigated by a peripheral chemosensory irritation study, and by acute and repeated exposure toxicity studies. The sensory irritation study, conducted with male Swiss Webster mice, showed an exposure concentration-related depression of breathing rate that allowed the calculation of an RD50 of 5140 mg m(-3). In an acute study male and female Sprague Dawley rats were exposed whole body to aerosols of TEG up to 6730 mg m(-3) for 4 h. No mortalities occurred at this high concentration, but unexplained mortality occurred in female rats at 5230 mg m(-3) at 2-3 days postexposure. Two repeats of the 5230 mg m(-3) exposure did not cause mortality. Signs at 6730 and 5230 mg m(-3) were limited to those of irritancy. For a 9 day repeated exposure study rats were exposed whole body to 0, 494, 2011 and 4824 mg m(-3) TEG aerosols for 6 h day(-1). Mortalities occurred at 4824 mg m(-3) between exposure days 2 and 5. Nonspecific indications of toxicity at 2011 mg m(-3) were signs of irritation, decreased body weight and increased food and water consumption; evidence of hepatic dysfunction was indicated by increased serum alkaline phosphatase and alanine aminotransferase activities, but liver histology was normal. Fluid imbalance was suggested by increases in water consumption, blood urea nitrogen, relative kidney weight and urine volume, with decreased urine osmolality, pH and N-acetyl-beta-D-glucosaminidase activity. At 494 mg m(-3) there were minimal signs of irritation, increased water consumption and slightly increased alkaline phosphatase; histology of the kidney was normal. Thus, in this 9 day repeated aerosol whole body exposure study a No-Observed-Effect-Level (NOEL) could not be established. Since preening of the fur at these high aerosol concentrations exposures might have led to a confounding factor from the resultant oral intake, another 9 day repeated aerosol study was conducted, but by nose-only exposure of rats for 6 h day(-1) to TEG aerosol concentrations of 0, 102, 517 and 1036 mg m(-3). In this study there were no clinical signs, no effects on food and water consumption, and no biochemical or histological evidence of hepatorenal dysfunction. By the end of the exposure period, male and female rats of the 1036 mg m(-3) group had body weights lower than those of the controls, but not with statistical significance. Since there were no statistically significant effects on any monitors, 1036 mg m(-3) is considered to be a threshold for toxicity by nose-only exposure to TEG aerosol. The findings indicate that exposure to a respirable aerosol is not acutely harmful, but may cause sensory irritant effects. Repeated exposure to high concentrations of TEG aerosols may be harmful, particularly if there are contributions from additional routes of exposure.

Administration, Inhalation↗
PubMed1997

Nitrogen availability of grape juice limits killer yeast growth and fermentation activity during mixed-culture fermentation with sensitive commercial yeast strains.

The competition between selected or commercial killer strains of type K2 and sensitive commercial strains of Saccharomyces cerevisiae was studied under various conditions in sterile grape juice fermentations. The focus of this study was the effect of yeast inoculation levels and the role of assimilable nitrogen nutrition on killer activity. A study of the consumption of free amino nitrogen (FAN) by pure and mixed cultures of killer and sensitive cells showed no differences between the profiles of nitrogen assimilation in all cases, and FAN was practically depleted in the first 2 days of fermentation. The effect of the addition of assimilable nitrogen and the size of inoculum was examined in mixed killer and sensitive strain competitions. Stuck and sluggish wine fermentations were observed to depend on nitrogen availability when the ratio of killer to sensitive cells was low (1:10 to 1:100). A relationship between the initial assimilable nitrogen content of must and the proportion of killer cells during fermentation was shown. An indirect relationship was found between inoculum size and the percentage of killer cells: a smaller inoculum resulted in a higher proportion of killer cells in grape juice fermentations. In all cases, wines obtained with pure-culture fermentations were preferred to mixed-culture fermentations by sensory analysis. The reasons why killer cells do not finish fermentation under competitive conditions with sensitive cells are discussed.

Antibiosis↗
PubMed1994

Metabolic response to lower abdominal surgery: analgesia by epidural blockade compared with intravenous opiate infusion.

To determine whether the type of peri-operative analgesic regimen affects the metabolic response during and after surgery, we studied 19 women undergoing abdominal hysterectomy under propofol anaesthesia. Patients were randomized to receive either continuous intravenous opioid or a bupivacaine-opioid mixture through a lumbar epidural catheter. Total body oxygen consumption and carbon dioxide excretion, blood glucose and haemodynamic variables were determined up to 24 h after surgery. No differences in any metabolic or haemodynamic variables were noted during surgery. In the post-operative period, the increase in oxygen consumption up to pre-operative values, the urinary nitrogen excretion and the changes in acute phase proteins were similar in both treatment groups. In contrast, the respiratory quotient was significantly higher in the lumbar epidural group than in the intravenous opioid group, 0.87 (SD 0.04) vs 0.77 (SD 0.06) (P < 0.05) and the hyperglycaemic response was more delayed in the epidural group. These data suggest that prolonged sympathetic blockade associated with epidural analgesia might contribute to better preservation of glucose homeostasis in the perioperative period.

Acute-Phase Proteins↗