Exogenous carbon and nitrogen requirements for conidial germination by Aspergillus flavus

1972 ◽  
Vol 18 (9) ◽  
pp. 1453-1461 ◽  
Author(s):  
T. Pass ◽  
G. J. Griffin
Keyword(s):  
Amino Acid ◽  
Aspergillus Flavus ◽  
Nitrogen Sources ◽  
Amino Acid Mixture ◽  
Conidial Germination ◽  
Tween 20 ◽  
Acid Mixture ◽  
Carbon And Nitrogen ◽  
Amino Acid Mixtures ◽  
Carry Over

In a phosphate-buffered (pH 5.7) inorganic salts solution (B), nearly full dependence on exogenous carbon was found for germination of washed, Tween 20-treated conidia of Aspergillus flavus over a range of conidial densities. No exogenous carbon-independent germination was observed for settling tower-deposited dry conidia. At equivalent carbon, an amino acid mixture supported highest germination of washed conidia; proline, alanine, or glucose plus NH4Cl supported higher germination than several other single amino acids or single sugars plus NH4Cl tested. When exogenous carbon was supplied as glucose, total and percentage germination of washed conidia were influenced more by exogenous nitrogen, supplied as NH4Cl, as the conidial density increased and as the glucose and NH4Cl concentrations increased. At equivalent nitrogen, proline alone, or certain amino acid mixtures supported highest germination of several nitrogen sources in B solution plus glucose. Germination decreased as the conidial density decreased when exogenous carbon and nitrogen were supplied at each density at constant amounts per conidium. Removal of CO2 from the germination medium inhibited germination. Tween 20 and Tergitol NPX stimulated germination of settling tower-deposited conidia. "Amino acid carry-over" for conidial germination was not demonstrated. The possible relation of these findings to the ecology of conidial germination in soil is discussed.

scholarly journals Effect of co-ingestion of amino acids with rice on glycaemic and insulinaemic response

2015 ◽  
Vol 114 (11) ◽  
pp. 1845-1851 ◽  
Author(s):  
Yean Yean Soong ◽  
Joseph Lim ◽  
Lijuan Sun ◽  
Christiani Jeyakumar Henry
Keyword(s):  
Amino Acids ◽  
Blood Glucose ◽  
Amino Acid ◽  
Glycaemic Index ◽  
Amino Acid Mixture ◽  
Postprandial Blood Glucose ◽  
Acid Mixture ◽  
White Rice ◽  
Amino Acid Mixtures

AbstractConsumption of high glycaemic index (GI) and glycaemic response (GR) food such as white rice has been implicated in the development of type 2 diabetes. Previous studies have reported the ability of individual amino acids to reduce GR of carbohydrate-rich foods. Because of the bitter flavour of amino acids, they have rarely been used to reduce GR. We now report the use of a palatable, preformed amino acid mixture in the form of essence of chicken. In all, sixteen healthy male Chinese were served 68 or 136 ml amino acid mixture together with rice, or 15 or 30 min before consumption of white rice. Postprandial blood glucose and plasma insulin concentrations were measured at fasting and every 15 min after consumption of the meal until 60 min after the consumption of the white rice. Subsequent blood samples were taken at 30-min intervals until 210 min. The co-ingestion of 68 ml of amino acid mixture with white rice produced the best results in reducing the peak blood glucose and GR of white rice without increasing the insulinaemic response. It is postulated that amino acid mixtures prime β-cell insulin secretion and peripheral tissue uptake of glucose. The use of ready-to-drink amino acid mixtures may be a useful strategy for lowering the high-GI rice diets consumed in Asia.

scholarly journals Dietary amino acids: effect of depletion and recovery on synthesis in vitro in rat skeletal muscle and liver

1974 ◽  
Vol 31 (1) ◽  
pp. 67-76 ◽  
Author(s):  
P. T. Omstedt ◽  
Alexandra Von Der Decken
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Energy Levels ◽  
Wheat Gluten ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Amino Acid Mixtures ◽  
Wet Weight ◽  
Ribosomal Activity

1. Rats were given diets containing 200 g/kg of a complete or incomplete amino acid mixture or of high- or low-quality proteins. After 6 d the amino acid-incorporating activity of ribosomes from skeletal muscle and liver was studied.2. The level of isotope incorporation relative to ribosomal RNA was similar for casein supplemented with methionine and for a complete amino acid mixture with the composition of whole-egg protein. Per wet weight of tissue there was a significant decrease after feeding with the complete amino acid mixture.3. There was a significant decrease in activity after feeding with amino acid mixtures deficient in lysine, methionine or tryptophan. In skeletal muscle, but not in liver, the ribosomal activity was less than that obtained with wheat gluten. Activity per wet weight of both tissues was less than that obtained with wheat gluten.4. Refeeding with methionine for 1 d resulted in complete restoration of ribosomal activity and activity per wet weight in skeletal muscle.5. After lysine deficiency, protein synthesis per unit wet weight of both tissues and ribosomal activity in liver were not restored after 2 d of refeeding. Recovery of ribosomal activity in skeletal muscle was complete after 1 d.6. Rats receiving the 200 g casein/kg diet supplemented with methionine at daily energy levels of 263, 176, 141 and 106 KJ (62.6, 42.1, 33.7 and 25.3 kcal) showed no changes in ribosomal activity, but there was a significant decrease in activity per wet weight when 106 KJ were given.

scholarly journals Antidopaminergic effects of dietary tyrosine depletion in healthy subjects and patients with manic illness

2001 ◽  
Vol 179 (4) ◽  
pp. 356-360 ◽  
Author(s):  
S. F. B. McTavish ◽  
M. H. McPherson ◽  
C. J. Harmer ◽  
L. Clark ◽  
T. Sharp ◽  
...  
Keyword(s):  
Amino Acid ◽  
Healthy Volunteers ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Double Blind ◽  
Amino Acid Mixtures ◽  
Tyrosine Depletion ◽  
Dsm Iv ◽  
To Receive ◽  
The Brain

BackgroundIn rats, amino acid mixtures lacking tyrosine and its precursor phenylalanine decrease the release of dopamine produced by the psychostimulant drug amphetamine. Amphetamine has been proposed as a model for clinical mania.AimsTo assess whether dietary tyrosine depletion attenuates the psychostimulant effects of methamphetamine in healthy volunteers and diminishes the severity of mania in acutely ill patients.MethodSixteen healthy volunteers received a tyrosine-free amino acid mixture and a control mixture in a double-blind crossover design 4 h before methamphetamine (0.15 mg/kg). Twenty in-patients meeting DSM–IV criteria for mania were allocated blindly and randomly to receive either the tyrosine-free mixture or the control mixture.ResultsThe tyrosine-free mixture lowered both subjective and objective measures of the psychostimulant effects of methamphetamine. Ratings of mania were lower in the patients who received the tyrosine-free mixture.ConclusionsDecreased tyrosine availability to the brain attenuates pathological increases in dopamine neurotransmission following methamphetamine administration and putatively in mania.

Soil fungistasis: elevation of the exogenous carbon and nitrogen requirements for spore germination by fungistatic volatiles in soils

1975 ◽  
Vol 21 (10) ◽  
pp. 1468-1475 ◽  
Author(s):  
Gary J. Griffin ◽  
T. S. Hora ◽  
Ralph Baker
Keyword(s):  
Spore Germination ◽  
Fusarium Solani ◽  
Inorganic Salt ◽  
Amino Acid Mixture ◽  
Conidial Germination ◽  
Acid Mixture ◽  
Nutritional Requirements ◽  
Carbon And Nitrogen ◽  
Soluble Compound ◽  
Soil Fungistasis

Axenic, washed conidia of Fusarium solani f. sp. phaseoli, Aspergillus flavus, and Verticillium albo-atrum were placed on washed Difco purified agar discs along with an inorganic salt solution containing various levels of carbon and nitrogen substrates. These discs were exposed to volatiles from six soils (pH 5.1–8.6). Fusarium solani macroconidial germination was inhibited mostly by volatiles from soils of pH 5.1, 6.1, 7.0, and 7.5, but high levels of glucose and NH4Cl reversed this inhibition, raising germination to that of no-soil, no-carbon or nitrogen controls. Conidial germination of A. flavus was inhibited mainly by volatiles from high pH (7.0, 7.8, and 8.6) soils, and increased levels of glucose plus an amino acid mixture nullified this inhibition. Volatiles from soils of pH 5.1, 6.1, and 7.5 stimulated A. flavus conidial germination. Assays after the removal of CO2 from the air above soil of pH 5.1 demonstrated that volatiles inhibitory to A. flavus were produced by this soil. Assays indicated that a KOH-soluble compound was a fungistatic soil volatile to F. solani macroconidial germination. The nullification by carbon and nitrogen substrates of F. solani and A. flavus inhibition caused by soil volatiles parallels that for soil fungistasis. Conidial germination of V. albo-atrum was markedly stimulated by volatiles in all soils tested, and was not affected by removal of CO2. Inhibitory soil volatiles may increase the nutritional requirements for spore germination of certain fungi.

scholarly journals The effect of feeding with a tryptophan-free amino acid mixture on rat liver magnesium ion-activated deoxyribonucleic acid-dependent ribonucleic acid polymerase

1970 ◽  
Vol 120 (1) ◽  
pp. 205-214 ◽  
Author(s):  
A. R. Henderson
Keyword(s):  
Amino Acid ◽  
Rna Polymerase ◽  
Rat Liver ◽  
Acid Concentration ◽  
Polymerase Activity ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Amino Acid Mixtures ◽  
Rna Polymerase Activity ◽  
Tryptophan Concentration

1. The Widnell & Tata (1966) assay method for Mg2+-activated DNA-dependent RNA polymerase was used for initial-velocity determinations of rat liver nuclear RNA polymerase. One unit (U) of RNA polymerase was defined as that amount of enzyme required for 1 mmol of [3H]GMP incorporation/min at 37°C. 2. Colony fed rats were found to have a mean RNA polymerase activity of 65.9μU/mg of DNA and 18h-starved rats had a mean activity of 53.2μU/mg of DNA. Longer periods of starvation did not significantly decrease RNA polymerase activity further. 3. Rats that had been starved for 18h were used for all feeding experiments. Complete and tryptophan-deficient amino acid mixtures were given by stomach tube and the animals were killed 15–120min later. The response of RNA polymerase to the feeding with the complete amino acid mixture was rapid and almost linear over the first hour of feeding, resulting in a doubling of activity. The activity was still elevated above the starvation value at 120min after feeding. The tryptophan-deficient amino acid mixture produced a much less vigorous response about 45min after the feeding, and the activity had returned to the starvation value by 120min after the feeding. 4. The response of RNA polymerase to the feeding with the complete amino acid mixture was shown to occur within a period of less than 5min to about 10min after the feeding. 5. Pretreatment of the animals with puromycin or cycloheximide was found to abolish the 15min RNA polymerase response to the feeding with the complete amino acid mixture, but the activity of the controls was unaffected. 6. The characteristics of the RNA polymerase from 18h-starved animals and animals fed with the complete or incomplete amino acid mixtures for 1h were examined. The effects of Mg2+ ions, pH, actinomycin D and nucleoside triphosphate omissions were determined. The [Mg2+]– and pH–activity profiles of the RNA polymerase from the animal fed with the complete mixture appeared to differ from those of the enzyme from the other groups, but this difference is probably not significant. 7. [5-3H]Orotic acid incorporation by rat liver nuclei in vivo was shown to be affected by the amino acid mixtures in a similar manner to the RNA polymerase. 8. The tryptophan concentrations of plasma and liver were determined up to 120 min after feeding with the amino acid mixtures. Feeding with the complete mixture produced a rapid increase in free tryptophan concentrations in both plasma and liver, but feeding with the incomplete mixture did not alter the plasma concentration. The liver tryptophan concentration increased at about 45min after feeding with the tryptophan-deficient diet. 9. There was a good correlation between the liver tryptophan concentration and RNA polymerase activity in all groups of animals. 10. It was concluded that the rat liver nucleus responded to an increase in amino acid supply by increased synthesis of RNA as a result of synthesis of RNA polymerase de novo. The correlation of tryptophan concentration and RNA polymerase activity appears to reflect the general amino acid concentration required to support hepatic protein synthesis and to produce new RNA polymerase. This new polymerase appears to differ from the basal RNA polymerase by its rapid synthesis and destruction, which may be a means of regulating RNA synthesis by the amino acid concentration in the liver.

scholarly journals Jejunal absorption of an amino acid mixture simulating casein and an enzymic hydrolysate of casein prepared for oral administration to normal adults

1975 ◽  
Vol 33 (1) ◽  
pp. 95-100 ◽  
Author(s):  
D. B. A. Silk ◽  
M. L. Clark ◽  
T. C. Marrs ◽  
Jill M. Addison ◽  
D. Burston ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Oral Administration ◽  
Human Subjects ◽  
Amino Nitrogen ◽  
Casein Hydrolysate ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Amino Acid Mixtures ◽  
Percentage Absorption

1. An intestinal perfusion technique was used in six normal human subjects to study absorption of sixteen individual amino acids from an amino acid mixture simulating casein and from an enzymic hydrolysate of casein, prepared for oral administration to these subjects, which consisted of a mixture of oligopeptides and free amino acids.2. Total absorption of α-amino nitrogen was greater from the casein hydrolysate than from the amino acid mixture, and the considerable variation in percentage absorption of individual amino acids from the amino acid mixture was much reduced when the enzymic hydrolysate solution was perfused, as a number of amino acids which were poorly absorbed from the amino acid mixture were absorbed to a greater extent from the casein hydrolysate.3. These findings indicate that after extensive intestinal resections or in malabsorption there might be significant nutritional advantages in the administration of protein hydrolysates rather than amino acid mixtures.

scholarly journals PLASMA PROTEIN AND HEMOGLOBIN PRODUCTION

1947 ◽  
Vol 85 (3) ◽  
pp. 243-265 ◽  
Author(s):  
F. S. Robscheit-Robbins ◽  
L. L. Miller ◽  
G. H. Whipple
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Protein ◽  
Nitrogen Balance ◽  
Essential Amino Acids ◽  
Amino Acid Mixture ◽  
Blood Protein ◽  
Acid Mixture ◽  
Amino Acid Mixtures ◽  
Urinary Nitrogen

Given healthy dogs fed abundant iron and protein-free or low protein diets with sustained anemia and hypoproteinemia, we can study the capacity of these animals to produce simultaneously new hemoglobin and plasma protein. Reserve stores of blood protein-building materials are measurably depleted and levels of 6 to 8 gm. per cent for hemoglobin and 4 to 5 gm. per cent for plasma protein can be maintained for weeks or months depending upon the intake of food proteins or amino acid mixtures. These dogs are very susceptible to infection and various poisons. Dogs tire of these diets and loss of appetite terminates many experiments. Under these conditions (double depletion) standard growth mixtures of essential amino acids are tested to show the response in blood protein output and urinary nitrogen balance. As a part of each tabulated experiment one of the essential amino acids is deleted from the complete growth mixture to compare such response with that of the whole mixture. Methionine, threonine, phenylalanine, and tryptophane when singly eliminated from the complete amino acid mixture do effect a sharp rise in urinary nitrogen. This loss of urinary nitrogen is corrected when the individual amino acid is replaced in the mixture. Histidine, lysine, and valine have a moderate influence upon urinary nitrogen balance toward nitrogen conservation. Leucine, isoleucine, and arginine have minimal or no effect upon urinary nitrogen balance when these individual amino acids are deleted from the complete growth mixture of amino acids during 3 to 4 week periods. Tryptophane and to a less extent phenylalanine and threonine when returned to the amino acid mixture are associated with a conspicuous preponderance of plasma protein output over the hemoglobin output (Table 4). Arginine, lysine, and histidine when returned to the amino acid mixture are associated with a large preponderance of hemoglobin output. Various amino acid mixtures under these conditions may give a positive urinary nitrogen balance and a liberal output of blood proteins but there is always weight loss, however we may choose to explain this loss. These experiments touch on the complex problems of parenteral nutrition, experimental and clinical.

Amino Acid Concentrations in Portal Venous Plasma during Absorption from the Small Intestine of the Guinea Pig of an Amino Acid Mixture Simulating Casein and a Partial Enzymic Hydrolysate of Casein

1977 ◽  
Vol 52 (3) ◽  
pp. 259-267
Author(s):  
M. H. Sleisenger ◽  
D. Pelling ◽  
D. Burston ◽  
D. M. Matthews
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Guinea Pig ◽  
Preliminary Investigation ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Analytical Technique ◽  
Amino Acid Mixtures ◽  
Amino Acid Concentrations ◽  
Venous Plasma

1. The characteristics of absorption of individual amino acids from amino acid mixtures simulating casein and from enzymic hydrolysates of casein containing oligopeptides as well as free amino acids are known to be different. The differences, which are attributable to mucosal uptake of small peptides, involve more rapid absorption from the enzymic hydrolysates of certain amino acids which are relatively slowly absorbed from the amino acid mixtures. This could lead to more effective utilization of amino acids from the enzymic hydrolysates than from the amino acid mixtures. 2. To obtain further information bearing on this hypothesis, we have used a recently developed technique for portal cannulation in the guinea pig to make a preliminary investigation of amino acid concentrations in the portal venous plasma at intervals after the infusion into the duodenum of equivalent amounts of (a) an amino acid mixture simulating casein and (b) a partial enzymic (papain followed by kidney peptidases) hydrolysate of casein, the two preparations being infused in separate experiments. 3. For some amino acids, such as leucine, isoleucine, valine, phenylalanine and lysine, the curves after the enzymic hydrolysate were fairly similar to the corresponding curves after the amino acid mixture, though usually slightly lower. With other amino acids, the curves after the enzymic hydrolysate were very much lower than the corresponding curves after the amino acid mixture. With serine, glutamine, proline and glycine this discrepancy was particularly great. 4. The results cannot yet be fully explained, but their main features are explicable by the hypothesis that the lower amino acid concentrations in portal plasma after the enzymic hydrolysate are the result of entry of amino acids into the portal blood in peptide form, in which they would not be detectable by the analytical technique employed, and possibly also of more rapid clearance of amino acids from the blood during absorption of this preparation.

Absorption of Amino Acids from an Amino Acid Mixture Simulating Casein and a Tryptic Hydrolysate of Casein in Man

1973 ◽  
Vol 45 (5) ◽  
pp. 715-719 ◽  
Author(s):  
D. B. A. Silk ◽  
T. C. Marrs ◽  
Jill M. Addison ◽  
D. Burston ◽  
M. L. Clark ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Total Absorption ◽  
Perfusion Technique ◽  
Double Lumen ◽  
Jejunal Absorption ◽  
Amino Acid Mixtures ◽  
Tryptic Hydrolysate

1. A double-lumen perfusion technique has been used in man to study jejunal absorption of individual amino acids from an amino acid mixture simulating casein, and a tryptic hydrolysate of casein consisting of oligopeptides and amino acids. 2. Total absorption was greater from the tryptic hydrolysate than from the amino acid mixture. There was wide variation in the extent to which individual amino acids were absorbed from the amino acid mixture. This was decreased when the tryptic hydrolysate was perfused. Amino acids which were particularly poorly absorbed from the amino acid mixture were absorbed to a substantially greater extent from the tryptic hydrolysate. 3. The results suggest that the characteristics of absorption of amino acid mixtures do not represent those of absorption of the physiological products of intraluminal digestion, oligopeptides and amino acids.

Food Preferences Acquired by Association with Variations in Amino Acid Nutrition

1971 ◽  
Vol 23 (1) ◽  
pp. 135-145 ◽  
Author(s):  
D. A. Booth ◽  
P. C. Simson
Keyword(s):  
Amino Acid ◽  
Essential Amino Acid ◽  
Free Amino ◽  
Food Preferences ◽  
Free Food ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Water Load ◽  
Amino Acid Mixtures ◽  
Anorexigenic Effect

Protein-deprived rats were given, on one day, a balanced mixture of amino acids followed by access to protein-free food having a distinctive odour. On another day, an imbalanced (histidine-free) amino acid mixture was given just before food having another odour. The rats afterwards preferred the balance-paired odour to the imbalance-paired odour. The preference was acquired whether the duration of odour presentation, or the amount of odourised food taken, was kept constant on the two conditioning days. Retention of the preference seemed unattenuated after 4 weeks. An attraction to the balance-paired odour (relative to odours paired with a water load) contributed to the acquired preference. There was also a relative aversion to unfamiliar odours when they had been paired with imbalance. Such acquired chemosensory control of preferences, together with an anorexigenic effect of imbalanced amino acid mixtures, can account for characteristics of feeding behaviour under conditions in which the diet is deficient in an essential amino acid.

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