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At least 109 records · Page 6Linked to original sources
PubMed2006

Effects of salinity on physiological conditions in juvenile common snook Centropomus undecimalis.

This study describes the effects of different salinities on oxygen consumption, ammonia excretion, osmotic pressure, apparent heat increment, postprandial nitrogen excretion, and oxygen:nitrogen ratio in juvenile common snook Centropomus undecimalis. Oxygen consumption of fish fasting and fish feeding was statistically different in relation with salinity. Fish maintained at 0, 25, and 35 ppt invested more energy processing feed than fish maintained at 12 ppt. Fasting fish had lower ammonia excretion than feeding fish and excretion was reduced at high salinities. Snook can change the energetic substrate in function with salinity, from a mixture of protein and lipids and carbohydrates at 35 ppt to a more acute preference for proteins at lower salinities. This species changes osmotic plasma concentrations at extreme experimental salinities. The different salinities were the snook inhabits (0-36 ppt), have a direct effect on the physiology, inducing changes on the oxygen consumption, nitrogen excretion, changes on the energetic substrate and plasma osmotic pressure.

Ammonia↗
PubMed1985

Subchronic toxicity studies of N-D-ornithyl amphotericin B methyl ester in dogs and rats.

Two subchronic studies were conducted to assess the potential toxicity of N-D-ornithyl amphotericin B methyl ester (OAME). In both studies the comparative control substance was amphotericin B (AMB). Dogs (5/sex/group) were given OAME (82% pure, based on high-pressure liquid chromatographic (HPLC) analysis) at 0.6, 2.5, and 10 mg/kg or AMB at 0.6 mg/kg intravenously once daily for 3 months. Two dogs per sex per group were retained for a 7-week postdose observation period. Rats (15/sex/group) were given daily doses of OAME at 4, 12, 24, and 36 mg/kg or AMB at 5 and 12 mg/kg intraperitoneally for 3 months. The principal organs of toxicity in both species were the liver, kidneys, and circulating erythrocytes. Hepatic changes in dogs consisted of periportal and centrilobular inflammation in animals of all dosed groups and were equivalent in dogs given 0.6 mg/kg OAME or AMB. In rats, acute hepatic necrosis with periportal, centrilobular, or panlobular distribution in animals of all OAME (except 4 mg/kg) and AMB-dosed groups was observed. These changes were equivalent in the 36-mg/kg OAME- and 12-mg/kg AMB-dosed animals. Renal changes, evidenced by increases in serum urea nitrogen water consumption, urine volume, decreased urine osmolality, and renal tubular changes (ranging from degeneration and regeneration to necrosis), were observed in both species. In dogs, these changes in the OAME-dosed animals were less severe at all doses than those observed in the AMB-dosed dogs. Renal changes in rats, which were mild in comparison to the dogs, were equivalent at doses of 5 and 12 mg/kg AMB and 36 mg/kg OAME. Decreased erythrocyte counts, hematocrit, and hemoglobin values were observed in both species. Unique to the dog study, however, were irreversible behavioral (somnolence, ataxia, tremors, and compulsive searching) and/or morphologic brain changes (gliosis with astrocytic hypertrophy and hyperplasia) at doses of 2.5 and 10 mg/kg OAME. Similar changes were observed in two dogs given 10 mg/kg OAME (100% pure, based on HPLC analysis) in a 6-week pilot study, indicating that the neurological changes were induced by OAME rather than by an impurity. These changes appear related to prolonged exposure to high plasma concentrations of OAME.

Alkaline Phosphatase↗
PubMed1998

[Biosynthesis of leucine aminopeptidase by Xanthomonas rubrilineans 67 in culture with various concentrations of nitrogen containing compounds].

The dynamics of consumption of amine and ammonium nitrogen and glucose in the process of Xanthomonas rubrilineans 67 growth and biosynthesis of leucine aminopeptidase was studied. It was shown that the rate of leucine, alanine and glycine consumption as a source of amine nitrogen out of 16 amino acids was the highest during the fermentation. Addition of these three amino acids or their mixtures to the medium at definite stages of the fermentation process increased the leucine aminopeptidase biosynthesis by 50 to 100 per cent. Ammonium nitrogen was not used by X.rubrilineans 67. The consumption of glucose during the fermentation was even: by the 24th hour of the process the medium contained about 10 per cent of the glucose initial concentration. The optimal temperature for the culture growth and leucine aminopeptidase biosynthesis was determined. It was shown to be 28 degrees C. Higher aeration increased the culture productivity.

Alanine↗
PubMed1996

Inhibition of lipolysis and muscle protein degradation by EPA in cancer cachexia.

Depletion of muscle and adipose tissue in cancer cachexia appears to arise not only from decreased food intake but also from the production of catabolic factors by certain tumours. Experiments with the cachexia-inducing MAC16 tumour in mice showed that when part of the carbohydrate calories were replaced by fish oil, host body weight loss was inhibited. The effect occurred without an alteration of either the total calorie consumption or nitrogen intake. Instead, one of the polyunsaturated fatty acids (PUFA) in fish oil, eicosapentaenoic acid (EPA), was found directly to inhibit tumour-induced lipolysis. The effect was structurally specific, as two related PUFA, docosahexaenoic acid (DHA) and gamma-linolenic acid (GLA), were without effect. The antilipolytic effect of EPA arose from an inhibition of the elevation of cyclic AMP in adipocytes in response to the lipid mobilizing factor. The increased protein degradation in the skeletal muscle of cachectic animals was also inhibited by EPA. This effect was due to the inhibition of the rise in muscle prostaglandin E2 in response to a tumour-produced proteolytic factor by EPA. Thus, reversal of cachexia by EPA in this mouse model results from its capacity to interfere with tumour-produced catabolic factors. Similar factors have been detected in human cancer cachexia.

Adenocarcinoma↗
PubMed2001

Growth, oxygen consumption, ammonia-N excretion, biochemical composition and energy content of Farfantepenaeus paulensis Pérez-Farfante (Crustacea, Decapoda, Penaeidae) early postlarvae in different salinities.

Physiological responses of early postlarval shrimp Farfantepenaeus paulensis to different salinities were evaluated. Growth, net growth efficiency (K(2)), oxygen consumption, ammonia-N excretion, protein, lipid, carbohydrate, ash and energy content were determined in postlarval stages PL VI-VII and PL XIII-XV at 5 per thousand, 15 per thousand, 25 per thousand and 34 per thousand. PL VI-VII and PL XIII-XV correspond, in the wild, to the penetration of postlarvae into estuarine zones and the adoption of benthic habits, respectively. Postlarvae were gradually acclimated to the various salinity levels in the stage PL VI-VII and were maintained there until reaching the stage PL XIII-XV. Although development time was not affected by salinity, growth was decreased at 34 per thousand. Oxygen consumption was less affected by salinity while ammonia-N excretion presented a negative correlation with salinity. In both stages, protein content was lower at 34 per thousand. In PL VI-VII, lipid was decreased at 5 per thousand, while no significant difference in lipid content was observed in PL XIII-XV. Carbohydrate and ash levels did not vary in function of salinity levels. Energy content was reduced in PL XIII-XV at 34 per thousand. Net growth efficiency (K(2)) between PL VI-VII and PL XIII-XV presented higher values at 15 per thousand and 25 per thousand, and the lowest at 34 per thousand. Enhanced energy expenditure due to osmoregulation was not detected as denoted by oxygen consumption rates. Nitrogen metabolism seems to play a key role in maintaining body fluids concentration in relation to medium salinity. It is concluded that the high degree of euryhalinity in these stages of F. paulensis may be an adaptation to ontogenetic events such as migration to estuarine areas. For aquaculture purposes, it is recommended to maintain these postlarval stages at salinities between 15 per thousand and 25 per thousand rather than 34 per thousand.

Journal Article↗
PubMed2026

Human Milk Oligosaccharides Modulate Nitrogen Utilization in Lactobacillus crispatus in a Glucose-Dependent Manner.

The vaginal microbiome's transition to a dysbiotic state increases susceptibility to pathogens like group B Streptococcus. While human milk oligosaccharides are established prebiotics in the neonatal gut, their impact on the vaginal niche remains largely unexplored. This study investigated the effects of pooled human milk oligosaccharides on the growth and physiology of vaginal (Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus iners) and gut-derived (Lactobacillus reuteri, Lactobacillus rhamnosus) commensals. Growth analyses revealed that human milk oligosaccharides significantly and selectively stimulated growth across all vaginal strains tested, whereas gut commensals exhibited variable or inhibited growth. Carbohydrate utilization assays and comparative genomics against Bifidobacterium infantis showed that Lactobacillus crispatus and Lactobacillus reuteri lack the canonical metabolic machinery to catabolize human milk oligosaccharides. Instead, nitrogen utilization assays identified a glucose-dependent pathway where human milk oligosaccharides are associated with the depletion of primary amines and amino acids in Lactobacillus crispatus supernatants. These results suggest that human milk oligosaccharides act as noncatabolic modulators of vaginal lactobacilli. Collectively, these in vitro findings may warrant investigation of human milk oligosaccharides as modulators of vaginal commensal physiology in more complex experimental systems.

Humans↗
PubMed1988

A comparison of long-chain triglycerides and medium-chain triglycerides on weight loss and tumour size in a cachexia model.

A comparison has been made between the ability of long-chain triglycerides (LCT) and medium-chain triglycerides (MCT) to prevent weight loss induced by the cachexia-inducing colon adenocarcinoma (MAC16) and to reduce tumour size. There was no difference in calorie consumption or nitrogen intake between the various groups. When compared with a normal control high carbohydrate, low fat diet, animals fed MCT showed a reduced weight loss and a marked reduction in tumour size. In contrast neither weight loss nor tumour size differed significantly from the controls in animals fed the LCT diet. An elevated plasma level of 3-hydroxybuturate was found only in the animals fed the MCT diets. Administration of LCT caused an increase in the plasma level of FFA, which was not observed in the MCT group. These results suggest that diets containing MCT would provide the best ketogenic regime to reverse the weight loss in cancer cachexia with a concomitant reduction in tumour size.

3-Hydroxybutyric Acid↗
PubMed1983

Energy metabolism rate equation for fasting and postabsorptive subjects.

The energy metabolism rate, an important parameter in severe clinical polytrauma and burns, is evaluated here using mass conservation law and simple thermodynamic considerations. The expressions for the energy and fat metabolism rates are evaluated utilizing easily measurable quantities: oxygen consumption, CO2 production, and nitrogen excretion rates. The derived equations are identical for the fasting and postabsorptive states, independent of feed composition. A new criteria for distinguishing between the fasting and postabsorptive states is suggested. These equations should help in evaluating energy metabolism rate for patients receiving continuous parenteral nutrition.

Calorimetry↗
PubMed1990

Inhibition of weight loss by omega-3 fatty acids in an experimental cachexia model.

The effect of substitution of the carbohydrate component of the diet by calories derived from fish oil on host body weight loss and tumor growth rate has been studied in an experimental colon adenocarcinoma (MAC16). This tumor produces extensive host weight loss and reductions in both total body fat and muscle dry weight, without a reduction in food intake. Diets containing fish oil significantly reduced host body weight loss, with almost complete protection occurring when the fish oil comprised 50% of the calories, without an alteration of total calorie consumption or nitrogen intake. There was also a significant reduction in tumor growth rate, although the reduction in host weight loss was greater than might be expected from a smaller tumor burden. The reduction of host body weight loss was associated with an increase in total body fat and muscle mass. The effect appears specific to the type of fat since comparable results were not obtained with a gamma-linolenic acid-enriched diet. When compared with cyclophosphamide and 5-fluorouracil the fish oil diet exerted a similar antitumor effect at the maximum dose. Whereas the antitumor effect of the former agents was achieved with considerable host toxicity, the latter produced no toxicity and almost completely abolished the cachectic effect of the tumor. These results suggest that fish oil is a nontoxic, highly effective anticachectic agent with the added advantage of antitumor activity.

Adenocarcinoma↗
PubMed1984

[Exclusive parenteral nutrition in children. Influence of continuous or cyclic intake on the utilization of food].

A continuous measurement of the energetic consumption and a nutritional evaluation were performed over 24 hours in two comparable groups of children under cyclic or continuous total parenteral nutrition (TPN). Over the 24 hours, energetic consumptions and nitrogenous retentions were equal in both groups. In cases submitted to continuous TPN, a similar utilization of nutriments was observed during the day and night periods, with global predominance of carbohydrate oxidation and of lipogenesis. In cases submitted to cyclic TPN, night and day utilization of nutriments was significantly different, with important utilization of glycogen and lipid stocks during the day. Thus, cyclic TPN allows a more important mobilization of the energetic stocks and physical activity during the day than continuous TPN and might change the quality of the weight gain and avoid an unnecessary storage of lipid deposits.

Calorimetry, Indirect↗
PubMed1980

Parenteral and enteral nutrition of the thermally injured patient.

The metabolic response to major thermal injury is characterized by gross hypermetabolism with increased basal metabolic rate, increased oxygen consumption, negative nitrogen balance and weight loss. Failure to provide burn patients with sufficient exogenous caloric and nitrogen intake results in catabolic sequelae; impaired wound healing, severe disturbances in regulation of cardiovascular, pulmonary and hepatorenal functions, as well as decreased resistance to infections leading to overt septic episodes. Vigorous nutritional therapy is therefore essential for the survival and optimal care of burn victims. In addition to enteral nutrition -- either by the oral route or with the help of tube feeding, parenteral nutrition is usually required to satisfy the extremely increased energy and protein requirements of the severely burned patient.

Basal Metabolism↗
PubMed1981

Microbial fixation of nitrogen in the presence of lanthanum sulphate.

The effect of lanthanum sulphate on five Azotobacter strains (4A7, 10, 5A2, 5A1, and 3A3) isolated from Allahabad soil consists in a considerable increase in the nitrogen fixation, carbon consumption and in the amount of nitrogen fixed in mg per g of carbon consumed. The presence of 200 microM, 300 microM and 400 microM lanthanum sulphate in culture media increases the fixation of nitrogen by all the nitrogen fixers significantly.

Azotobacter↗
PubMedDate not supplied

[Effect of replacement of air nitrogen by inert gases on oxygen consumption by the liver tissues in albino rats on various fatty diets].

The effects of helium and argon, inert gases, on oxygen consumption have been studied on liver tissue of white rats who were delivered different fatty products plus to basic food). It is shown that the effects of helium and argon on the tissue respiration depend on the nature of fatty products. The role of membrane structure in realization of the influence of inert gases on tissue respiration is under discussion.

Animals↗
PubMed2004

Removal of multiple nitrogenous wastes by Aspergillus niger in a continuous fixed-slab reactor.

A biofilter reactor, to which is attached a large variety of microorganisms, can be employed to treat circulating water in an intensive aquaculture system. Some nitrogen-containing wastes, such as ammonium and nitrite, are toxic to the aquatic organisms. The removal rates of the nitrogenous wastes are regarded as indices for the efficiency of treatment by biofilters. In this study, a fungus that was characterized as being able to remediate multiple nitrogenous wastes was identified as Aspergillus niger NBG5. In a continuous fixed-slab reactor, the heterotrophic fungus utilized ammonium, nitrite, protein, and glucose simultaneously. The fungus assimilated ammonium, nitrite and protein at rates of 0.247, 0.07 and 0.096 g-N/g-cell/day, respectively, at 22 degrees C. The remediation rates of ammonium nitrogenous wastes decreased by a factor of eight at 35 degrees C, while the specific growth rates slightly increased. For nitrogenous wastes, ammonium was a preferred substrate but its rate of consumption declined significantly as temperature increased. The nitrogen consumption rates were inconsistent with the cell yields at high temperature. Further analysis of consumption ratios of C/N revealed that cells grew predominantly from the carbon at high temperature. The A. niger NBG5 consumed glucose rapidly at specific rates of 2-2.5 g-C/g-cell/day at 35 degrees C in the presence of ammonium and nitrite; while sluggish consumption of glucose was observed in the protein substrate. The protein could serve as an alternative carbon source. Further ANOVA statistical analysis with P < 0.05 revealed no significant effects of temperature on the specific growth rates of A. niger on the SG-NH4 and milk-protein substrates, whereas significant effects on the C/N ratio at culture temperatures higher than 25 degrees C were observed. These findings indicated that the carbon utilization rate increased with high temperature, whereas nitrogen utilization increased as temperature declined. A suitable operational temperature was suggested, depending upon the amount of waste contents of C/N. A high temperature stimulates the use of carbon waste, while a low temperature favors remediation of all nitrogenous wastes.

Analysis of Variance↗