Nutritional Control of Differentiation (Sclerotization) of the Myxomycete Physarum flavicomum

1975 ◽  
Vol 53 (7) ◽  
pp. 810-818 ◽  
Author(s):  
Henry R. Henney Jr. ◽  
Glenna Maxey
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Adenosine Monophosphate ◽  
Cellular Protein ◽  
Amino Acid Pool ◽  
Differentiation Process ◽  
Ammonium Ions ◽  
Morphological Alterations ◽  
Acid Pool ◽  
Nutrient Imbalance

During differentiation (sclerotization) of the Myxomycete Physarum flavicomum, the acellular Plasmodium converts into numerous dormant cells surrounded by cell walls. This work establishes that a condition of nutrient imbalance triggers the differentiation process. Specifically, the unavailability of an adequate spectrum of amino acids in the medium initiates the metabolic and morphological alterations characteristic of the sclerotizing Plasmodium.In the absence of extracellular amino acids, the cellular pool of amino acids and cellular protein were catabolized as differentiation proceeded. The pattern of amino acids in the cellular pool also changed during differentiation, as the content of pool amino acids was reduced at least 75%. The decrease in protein content was negligible after 12 h incubation but was about 40% at 48 h when differentiation was complete. However, in the presence of extracellular amino acids, protein degradation, amino acid pool depletion, and differentiation were all inhibited. Ammonium ions (12.4 mM) similarly delayed differentiation.Differentiation, amino acid pool depletion, and the degradation of cellular protein readily occurred in the presence of an extracellular supply of dextrose, which stimulated cell wall formation. The effect of dimethyl sulfoxide, cyclic 3′,5′-adenosine monophosphate, glutathione, diamide, and other compounds on the differentiation process are reported also.

Adaptational changes in Staphylococcus aureus MF31 grown above its maximum temperature when protected by NaCl: physiological studies

1984 ◽  
Vol 30 (9) ◽  
pp. 1105-1111 ◽  
Author(s):  
A. Hurst ◽  
Esther Ofori ◽  
A. A. El-Banna ◽  
J. Harwig
Keyword(s):  
Amino Acids ◽  
Staphylococcus Aureus ◽  
Amino Acid ◽  
Monosodium Glutamate ◽  
Amino Acid Pool ◽  
Maximum Temperature ◽  
C Cells ◽  
Acid Pool ◽  
High Concentrations ◽  
P Cells

Staphylococcus aureus MF31 can grow at 46 °C, 2 °C above its normal maximum temperature of growth if 1 M NaCl is added to the medium. In the present work we show that monosodium glutamate, proline, threonine, aspartic acid, and betaine (in order of decreasing effectiveness) also enabled cells to grow at 46 °C. Cells grown at 46 °C in he presence of salt (protected or P cells) accumulated glutamate more rapidly than cells grown at 37 °C without salt (normal or N cells) and contained an increased amino acid pool. The principal constituents of this pool were dicarboxylic amino acids and proline. Turbidimetric evidence suggests that NaCl caused plasmolysis in S. aureus. The P cells, although grown in 1 M NaCl, had about the same Cl− and K+ content as the N cells grown without added NaCl. P cells had increased heat resistance but high concentrations of CaCl2 in the heating menstruum reduced their D55 value from a maximum of 214 min to < 30 s. We suggest that growth at 46 °C in 1 M NaCl can be explained, in part at least, by the increased amino acid pool internal to the cell and the external osmotic support given by Cl− anions excluded by the cell.

scholarly journals Hypoxic Adaptation of Mitochondrial Metabolism in Rat Cerebellum Decreases in Pregnancy

Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 139 ◽  
Author(s):  
Anastasia Graf ◽  
Lidia Trofimova ◽  
Alexander Ksenofontov ◽  
Lyudmila Baratova ◽  
Victoria Bunik
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Metabolic Network ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Amino Acid Pool ◽  
Pregnant Rats ◽  
Acid Pool ◽  
Rat Cerebellum ◽  
Amino Acid Levels

Function of brain amino acids as neurotransmitters or their precursors implies changes in the amino acid levels and/or metabolism in response to physiological and environmental challenges. Modelling such challenges by pregnancy and/or hypoxia, we characterize the amino acid pool in the rat cerebellum, quantifying the levels and correlations of 15 amino acids and activity of 2-oxoglutarate dehydrogenase complex (OGDHC). The parameters are systemic indicators of metabolism because OGDHC limits the flux through mitochondrial TCA cycle, where amino acids are degraded and their precursors synthesized. Compared to non-pregnant state, pregnancy increases the cerebellar content of glutamate and tryptophan, decreasing interdependence between the quantified components of amino acid metabolism. In response to hypoxia, the dependence of cerebellar amino acid pool on OGDHC and the average levels of arginine, glutamate, lysine, methionine, serine, phenylalanine, and tryptophan increase in non-pregnant rats only. This is accompanied by a higher hypoxic resistance of the non-pregnant vs. pregnant rats, pointing to adaptive significance of the hypoxia-induced changes in the cerebellar amino acid metabolism. These adaptive mechanisms are not effective in the pregnancy-changed metabolic network. Thus, the cerebellar amino acid levels and OGDHC activity provide sensitive markers of the physiology-dependent organization of metabolic network and its stress adaptations.

Effects of larval Digenea on the free amino acid pool of Littorina littorea (L.)

Parasitology ◽  
1971 ◽  
Vol 62 (3) ◽  
pp. 361-366 ◽  
Author(s):  
Stuart D. M. Watts
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Total Concentration ◽  
Amino Acid Pool ◽  
Littorina Littorea ◽  
Free Amino Acid Pool ◽  
Acid Pool

Quantitative chromatographic analysis of the free amino acids of the head–foot muscle of uninfected and infected Littorina littorea indicates that there is specific variation in the physiological effects of parasitism. The total concentration of free amino acids in the host head–foot muscle showed an increase of 10·9% with infections of Cryptocotyle lingua rediae, a decrease of 12·7% with infections of Himasthla leptosoma rediae and a decrease of 57·5% with infections of Cercaria emasculans sporocysts. These effects probably depend on three main factors namely, the nature, size and mobility of the larvae of the three species concerned and the influence of these factors in determining the extent of any damage to the hepatopancreas of the host.The larvae of C. lingua are probably less affected by the changes they induce in the free amino acid pool of the host than the larvae of H. leptosoma and Cercaria emasculans which induce changes equivalent to starvation.This work was conducted during the tenure of a Science Research Council Studentship. I would like to thank Professor B. John and Mr A. R. Hockley for their helpful advice and criticism.

scholarly journals Regulation of enzyme turnover during tissue differentiation. Interactions of insulin, prolactin and cortisol in controlling the turnover of fatty acid synthetase in rabbit mammary gland in organ culture

1976 ◽  
Vol 154 (2) ◽  
pp. 359-370 ◽  
Author(s):  
Brian K. Speake ◽  
Raymond Dils ◽  
R. John Mayer
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Fatty Acid ◽  
Amino Acid ◽  
Culture Medium ◽  
Fatty Acid Synthetase ◽  
Amino Acid Pool ◽  
Acid Pool ◽  
Intracellular Amino Acid ◽  
Enzyme Degradation

1. Explants of mammary gland from mid-pregnant rabbits were cultured in Medium 199 containing combinations of insulin, prolactin and cortisol. With hormone combinations which included prolactin, a sustained increase in the apparent rate of synthesis and in the amount of fatty acid synthetase was measurable immunologically. Maximum increase was produced with insulin, prolactin and cortisol present together. 2. With prolactin present alone, synthetase activity in the explants decreased to undetectable values after 1 day in culture, whereas the incorporation of l-[U-14C]leucine into immunodetectable material increased. Prolactin may therefore direct the synthesis of immunologically cross-reactive precursors of fatty acid synthetase which are enzymically inactive. 3. Culture with dibutyryl cyclic AMP plus theophylline in the presence of insulin, prolactin and cortisol delayed the increase in the rate of synthesis and accumulation of the synthetase. These compounds may also prevent the apparent decrease in the rate of degradation of the synthetase which occurs on day 2 of culture. 4. A large decrease in the apparent rate of degradation of the synthetase on day 2 of culture occurs during culture with hormone combinations which include prolactin. The protein obtained by centrifugation of explant homogenates for 6min at 14000gav. is degraded continuously throughout the culture period. 5. This decrease in the apparent rate of degradation of the synthetase was measured by radio-immunological precipitation. It is probably part of a regulated programme of enzyme degradation and not a reflexion of the reutilization of radioactive amino acids for the following reasons. (a) The calculated increase in the amount of the synthetase in explants on day 2 of culture with insulin, prolactin and cortisol was approximately equal to the measured increase of the enzyme complex which accumulates in the explants. This suggests little or no enzyme degradation has occurred. (b) Explants were cultured for 24h with insulin, prolactin and cortisol. They were then incubated with l-[U-14C]leucine, washed and incubated again for up to 4½h. l-[U-14C]Leucine rapidly equilibrated with the intracellular amino acid pool. Within 10min of incubation after washing explants to remove endogenous l-[U-14C]leucine the previously linear incorporation of l-[U-14C]-leucine into total explant protein ceased. This suggests that protein is synthesized from an amino acid pool which rapidly equilibrates with amino acids in the culture medium. (c) Explants were cultured for 24h as described in (b) but after washing they were cultured with insulin, prolactin and cortisol for 24h. Approx. 90% of the radioactivity lost from the ‘free’ intracellular amino acid pool and from amino acids derived from the degradation of explant protein in this period was detected in the culture medium. This suggests that the ‘free’ intracellular amino acids and amino acids derived from protein degradation can equilibrate with amino acids in the medium. A residual ‘free’ radioactive amino acid pool was present in the tissue. (d) Casein represents approx. 20% of the protein synthesized after 1 day in culture with insulin, prolactin and cortisol. Histological evidence suggests that on day 2 of culture, casein is unlikely to be degraded in the tissue. No increase in the radioactivity incorporated into casein can be measured in the 23h after incubation of explants with l-[U-14C]leucine as described in (b). This suggests that the incorporation of radioactivity into proteins during culture after incubation with l-[U-14C]leucine is minimal. (e) Inhibition of protein synthesis in explants by cycloheximide after incubation with l-[U-14C]leucine does not reveal a latent continuous degradation of fatty acid synthetase on day 2 of culture which might have been masked by the high rates of protein synthesis and therefore the accumulation of the enzyme. 6. The conclusion is discussed that there is a real decrease (or even cessation) in the rate of degradation of fatty acid synthetase during the period when the enzyme accumulates in explants cultured with hormone combinations which contain prolactin.

Correlations between the amino acid pools of Hymenolepis diminuta and the rat intestine

1975 ◽  
Vol 53 (3) ◽  
pp. 320-331 ◽  
Author(s):  
D. F. Mettrick
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Biosynthesis ◽  
Hymenolepis Diminuta ◽  
Amino Acid Pool ◽  
Acid Uptake ◽  
Rat Intestine ◽  
Time Intervals ◽  
Acid Pool ◽  
High Degree

The composition of the free and protein amino acid pools of the rat intestine and of 16-day-old Hymenolepis diminuta have been determined at 1000 and 1600 h under ad libitum feeding conditions. The molar concentration (μmol/g dry-wt.) of the total intestinal and worm amino acid pools remained constant through time, although quantitatively individual amino acids differed significantly. All of 16 amino acids determined differed significantly in the comparisons between the intestinal and worm amino acid pools and between the time intervals. There was a high degree of correlation between the time intervals. There was also a high degree of correlation between the intestinal and worm pools based on their quantitative ranking, supporting the conclusion that there is little selective capacity involved in amino acid uptake by H. diminuta.Between 1000 and 1600 h the total worm amino acid pool increased by 73 μmol, mainly as a result of an increase in protein amino acids, indicating that worm protein biosynthesis was not inhibited by the changes in the intestinal pools. As the luminal free amino acid pool averaged only 20 μmol over this period, uptake by the worms would be equivalent to 60% of the luminal pool per hour.This high level of nutritional predation by the worms may be tolerated by the host because of extensive mucosal peptide absorption. A similar ability by the worms may explain why they can also tolerate the extensive amino acid fluctuations and fluxes that have been demonstrated between helminth and lumen.

D-Amino acids of the amino acid pool and occurrence of racemase andD-amino acid oxidase activities inEscherichia coli B

1978 ◽  
Vol 23 (5) ◽  
pp. 341-348 ◽  
Author(s):  
R. P. Raunio ◽  
M. J. Munter ◽  
O. J. Jaakkola ◽  
J. T. Karppinen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Pool ◽  
Acid Oxidase ◽  
Inescherichia Coli ◽  
Amino Acid Oxidase ◽  
Acid Pool

scholarly journals Influence of Amino Acids on Low-Density Escherichia coli Responses to Nutrient Downshifts

2007 ◽  
Vol 189 (8) ◽  
pp. 3099-3105 ◽  
Author(s):  
Sergio Bodini ◽  
Luisa Nunziangeli ◽  
Francesca Santori
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Amino Acid ◽  
High Density ◽  
Amino Acid Pool ◽  
Affinity Constant ◽  
Lag Phase ◽  
Cell Recovery ◽  
Acid Pool ◽  
Amino Acid Availability

ABSTRACT A vast bibliography on nutrient effects on high-density cultures exists, while it has been overlooked that low densities of starving cells are often the rule in natural environments. By means of a novel sensitive β-galactosidase assay, we examined Escherichia coli transitions to minimal media when the cell concentration was 100 to 10,000 cells per ml. As in high-density cultures, the enzyme activity depended on amino acid availability and was subject to catabolite repression and stringent control. In all conditions tested, despite the presence of other nutrient sources, the relationship between β-galactosidase activity and the l-amino acid pool was hyperbolic. The affinity constant when the amino acid pool was the only nutrient source averaged 14 μM after 90 min and increased up to 222 μM after 4.5 h. While investigating the transition from lag phase to exponential phase, we observed that the cells did not enter into starvation mode in the presence of amino acids, even when the nutrient amount was insufficient to support full survival. Based on these premises, the switch from starvation to hunger was investigated in relation to the amino acid pools. A critical range of concentrations at which E. coli linearly synthesized β-galactosidase despite, at the same time, suffering a large decrease in cell viability was then recognized. Since both β-galactosidase production and the dilution rate were reduced by more than half in the absence of leucine, we examined the contribution of leucine to cell recovery capabilities.

The effect of oxygen availability on the osmoregulatory contribution of free amino acids in Acanthamoeba castellanii

1986 ◽  
Vol 64 (7) ◽  
pp. 1430-1435 ◽  
Author(s):  
Yves Geoffrion ◽  
Helga Guderley ◽  
Jacques Larochelle
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Free Amino ◽  
Amino Acid Content ◽  
Amino Acid Pool ◽  
Free Amino Acid Content ◽  
Free Amino Acid Pool ◽  
Hyperosmotic Shock ◽  
Acid Pool

In Acanthamoeba, the availability of oxygen markedly affects the response to hyperosmotic (250 to 500 mosmol/kg water) or hypoosmotic (250 to 125 mosmol/kg water) stress. The short-term recovery of cell hydration after hyperosmotic shock was more rapid at a [Formula: see text] of 54 Torr (1 Torr = 133.322 Pa) than at 5 Torr, despite similar increases in the free amino acid content of the cell (2.3- to 2.4-fold). Under anoxia, the early response to both hyper- and hypo-osmotic stress resulted in osmometer-like cells and the osmoregulatory contribution of the free amino acid pool following hyperosmotic shock was totally abolished. After a hypoosmotic shock under anoxia, however, the decrease of the free amino acid pool, though much slower, was of the same magnitude as under aerobic conditions (1.8- to 2.5-fold). This was apparently the only osmoregulatory mechanism operative in the absence of oxygen. The free amino acid pool was qualitatively affected by the oxygenation level, with proline being more abundant at high [Formula: see text] and alanine being more important under low [Formula: see text] and anoxia. The oxygen consumption of the cells was essentially unaffected by osmotic stress and by the [Formula: see text] level. The osmotically induced changes in the free amino acid content of the cell involve flows of energy into and out of the free amino acid pool that appear considerable when compared with the energy available from oxidative metabolism. This suggests that de novo synthesis and complete oxidation have only a limited role in the supply and disposal of the free amino acids involved in osmotic regulation.

Studies on the free pool of amino acids of the cestodeHymenolepis diminuta

Parasitology ◽  
1973 ◽  
Vol 67 (3) ◽  
pp. 289-305 ◽  
Author(s):  
L. H. Chappell ◽  
C. P. Read
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Free Amino ◽  
Hymenolepis Diminuta ◽  
Amino Acid Pool ◽  
Absolute Amount ◽  
Free Amino Acid Pool ◽  
Acid Pool

Alteration of the free amino acid pool ofHymenolepis diminutawas observed following incubation of worms with a single exogenous amino acidin vitro, recovery from which depended upon the initial magnitude of alteration. The free amino acid pool of both rat small intestine andH. diminutawas rendered imbalanced after feeding a single dietary dose of proline. Recovery was more rapid in the host than in the parasite tissues. The quantitative dynamics of amino acid change with time were examined. The effects of amino acid variation upon the uptake and incorporation of lysine-C14into worm protein were examinedin vitro. Four amino acids altered lysine incorporation; aspartate stimulated incorporation while ornithine, arginine and histidine reduced variously the absolute amount of lysine uptake but produced relative stimulation of lysine incorporation. These data indicate that, in the system examined, short term variation of the free amino acid pool is unlikely to affect protein synthesis inH. diminuta. Data were obtained suggesting the possible occurrence of certain amino acid inter conversions inH. diminuta.

scholarly journals Blood serum amino acid pool violation of in patients with liver cirrhosis

2021 ◽  
Vol 88 (1-2) ◽  
pp. 19-22
Author(s):  
O. P. Balazh
Keyword(s):  
Amino Acids ◽  
Liver Cirrhosis ◽  
Amino Acid ◽  
Blood Serum ◽  
Free Amino ◽  
High Performance ◽  
Reversed Phase ◽  
Amino Acid Pool ◽  
Acid Pool ◽  
Intestinal Dysbiosis

Objective. To investigate serum amino acid pool changes in patients with liver cirrhosis. Materials and methods. 95 patients with liver cirrhosis were participated in the study. In the 1st group (class A disease severity according to Child- Pugh score) there were 18 (18.95%) patients, in the 2nd group (class B) - 25 (26.3%), in the 3rd groups (class C) - 52 (54.7%) patients. The amount of free amino acids in blood serum was determined by reversed-phase high-performance liquid chromatography in isocratic elution mode with electrochemical detection. Results. Violations of free amino acid reserves were revealed in patients with cirrhosis of the liver with a predominant accumulation of aromatic amino acids: phenylalanine - (162.45 ± 14.12) nmol/ml, tyrosine - (99.05 ± 10.07) nmol/ml, tryptophan - (76.10 ± 12.40) nmol/ml, as well as an increase in the content of proline, lysine, cysteine (p <0.05) . In parallel, the decreasing of free serum amino acids with branched side chain levels were observed: valine - up (150.10 ± 8.92) nmol/ml leucine - up (75.14 ± 5.12) nmol/ml (p < 0.05) and isoleucine - up to (80.40 ± 8.01) nmol/ml. Conclusions. The correlation between the second degree of thick guts dysbiosis and increased levels of tryptophan was determined (r = 0.77; p <0.01). III degree thick dysbiosis was correlated with increasing levels of phenylalanine (r = 0.71; p <0.01). In patients of 2nd group the correlations between levels of tryptophan and II degree of intestinal dysbiosis (r = 0.58; p <0.01) and the levels of tyrosine in phenylalanine in III stage intestinal dysbiosis were detected.

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