THE INFLUENCE OF EXCESS METHIONINE ON THE FREE AMINO ACIDS OF BRAIN AND LIVER OF THE WEANLING RAT*

Abstract— —High circulating levels of l -methionine produced by inclusion in the diet or parenteral injection of the amino acid caused alterations in the free amino acid pattern of liver and brain tissues. Acute effects following l -methionine injection were more pronounced than those following long term feeding where adaptation played a role. The net effect following parenteral injection was to increase the total free amino acids of liver while decreasing those of brain. Individually, hepatic levels of aspartic acid, threonine, serine, glutamine, glutamic acid, glycine, and alanine were depressed while levels of taurine, cystathionine, methionine, lysine, and ornithine were markedly elevated. Brain levels of aspartic acid, threonine, serine, glutamic acid, glycine, alanine, and γ-aminobutyric acid were markedly depressed and increased levels of cystathionine, methionine, lysine, and glutamine were observed. A generalized aminoaciduria occurred shortly after excessive methionine intake. Disruption of the free amino acid pools was of two kinds. The first depended on the continued presence of excess l -methionine, the second did not.     

Quantitative analysis of free amino acids and carbohydrates in spring barley anthers at different stages of maturity

The content of the carbohydrates glucose, fructose and sucrose was determined in spring barley anthers at different stages of maturity. During maturation the sucrose content of the anthers increased markedly. The following 17 free amino acids were detected in anthers of different stages of maturity: aspartic acid, glutamic acid, serine, alanine, arginine, leucine, isoleucine, lysine, α-aminobutyric acid, glutamine, proline, tyrosine, phenylalanine, valine, threonine, cystine and glycine. Quantitative analysis was only carried out in amino acids present in higher concentrations in the analysed samples. These were: aspartic acid, glutamic acid, α-aminobutyric acid, proline, serine, valine and glutamine, and a mixture of amino acids (leucine, isoleucine, valine and phenylalanine). The total content of free amino acids increased with increasing maturity of the anthers. However, not all amino acids followed contributed to this increase, but only proline, glutamic acid, aspartic acid and glutamine. A small difference was found in the variety Gopal in which the aspartic acid content did not increase significantly, but the content of the mixture of amino acids and serine did. With the exception of green anthers of the variety Firlbecks Union, proline was present in the highest concentration in all samples analysed.     

Chemotaxis ofRhizobium sp. Towards root exudate ofCicer Arietinum L.

Summary Root exudate from seedlings ofCicer arietinum L. was collected in a chamber under aseptic conditions. The exudate was fractionated into anion, cation and neutral fractions. The anionic fraction was made up of galacturonic acid, gluconic acid, mannuronic acid and two unidentified compounds withR _f values 0.56 and 0.62. The cationic fraction contained alanine, arginine, aspartic acid, cystine, glycine, histidine, isoleucine, leucine, lysine and serine. The neutral fraction was made up of arabinose, galactose, glucose, ribose and xylose. The amino acids contributed to the bulk of the root exudate. The ratio of anionic, cationic and neutral fraction was 1∶7∶2. The crude root exudate was tested for its chemotactic ability using the capillary tube method. It was highly chemotactic for theRhizobium sp. The individual fractions and their various combinations were tested for chemotaxis. The chemotactic response of the Cicer strain of Rhizobium was least with anionic fraction most with cationic fraction and intermediate with neutral fraction. Maximum chemotactic response among the fractional combinations was obtained with all the three fractions and least with cationic plus neutral factions. Individual compounds constituting the various fractions were also tried for their ability to elicit chemotactic response. The organism exhibited maximum positive chemotactic response to histidine and negative response to alanine among the amino acids and to glucose and gluconic acid among the sugars and sugar acids.     

不同年龄小白鼠全脑细胞质氨酰tRNA合成酶活力的比较

从不同年龄(20天,30天,1年)的小白鼠全脑制得细胞质混合氨酰tRNA合成酶。用异源体系(即用酵母tRNA和小白鼠全脑氨酰tRNA合成酶)测定了氨酰tRNA合成酶分别载运~3H标记的Asp、Gly、Glu、Lys和Ala的活力。结果表明除未检出tRNA~(Glu)的合成酶活力外,对其余四种氨基酸都有明显的活力,特别是年龄20天小白鼠的氨酰tRNA合成酶对~3H-Gly具有高达35％的载运活力。对~3H-Gly、~3H-Lys和~3H-Ala的载运活力有随增龄而下降的趋势,但对~3H-Asp的载运活力则随年龄增长而增高。     

ELECTROSHOCK-INDUCED SEIZURES AND THE TURNOVER OF BRAIN PROTEIN IN THE RAT

Abstract— A total of ten electroshock seizures (two seizures per day) were induced in rats beginning 3 days after an injection of [U-¹⁴C]glucose. Despite the intense stimulation, the labelling of the protein and nucleic acid fractions in the brains of convulsed animals decreased only slightly and not significantly. During the first 2 days after administration of [¹⁴C]glucose to untreated animals, there was a slight decrease in the specific activity of protein-bound glutamic acid relative to that of aspartic acid and the total protein fraction, suggesting the presence of a protein with a high content of glutamic acid and a rapid turnover.     

Effects of induced hypothermia on amino acids and glycogen in rat brain

Abstract— The concentrations of free amino acids and glycogen in the cerebral cortex of normal and deeply hypothermic (body temperature 18–20°C) rats were measured. The significant changes which accompanied the induction of hypothermia were a large reduction in glutamic acid concentration and moderate increases in the concentrations of glutamine and aspartic acid. The concentrations of γ-aminobutyric acid, N-acetylaspartic acid and glycogen did not change significantly.     

Effect of variations in salinity and alkalinity of applied irrigation waters on the amino acid make-up of Phaseolus aureus

Summary A marked decrease in the content of various amino acids was observed when the boron concentration was increased from 0.5 to 2.0 ppm particularly at low value of SAR and low level of conductivity. At medium level of conductivity alongwith low level of boron increase in value of SAR definitely suppressed the content of lysine, arginine plus histidine, aspartic acid plus glutamine, threonine plus alanine, proline and cystine in plants. Increase in levels of conductivity specially at low value of SAR and low level of boron substantially affected the content of lysine, arginine plus histidine, aspartic acid plus glutamine, threonine plus alanine, proline and cystine.     

γ-Aminobutyric Acid Metabolism in Detached Leaves of Wheat Seedling and Leaves and Cotyledons of Sunflower

With a prerequisite of 5 hours in the light the detached leaves of wheat seedling and detached leaves and cotyledons of sunflower were able to utilize exogenous γ-aminobutyric acid, the amount of alanine and glutamine formed were increased. It was found that deamination of γ-aminobutyric acid was associated with γ-aminobutyric-pyruvate transaminase in the leaves of wheat seedling. The specific activity of this transaminase was enhanced about 5.6 fold by adsorption with calcium phosphate gel-Some properties of this transaminas were as follows: the optimum pH was 8.9. The produced amount of alanine was linear with time up to a period of one hour. The primary rate of reaction was proportional to enzyme concentration in the first hour. The relation of substrate concentration to the primary rate of alanine formation was determinated and Michaelis constant was evaluated about 2.6 × 10-3 M. The action of this transaminase in metabolism of γ-aminobutyrie acid was discussed.     

Rhipicephalus sanguineus: amino acid composition of egg shell

Acid hydrolysis of the protein fraction of a batch of egg shells of Rhipicephalus sanguineus was followed by determination of the amino acids in the hydrolysate. Using thin layer chromatography, the amino acids—lysine, arginine, aspartic acid, serine, glycine, glutamic acid, alanine, threonine, valine, tyrosine, isoleucine, and leucine were identified. Alkaline hydrolysis of the fraction followed by TLC revealed the presence of tryptophane. Chitin was revealed utilizing a chitosan test.     

Dynamics of the amino acid composition of the medium during cultivation of isolated organs by the directed perfusion method]

The dynamics of the amino acid composition of the medium under conditions of adequate perfusion of the isolated organs of a dog (sternum, kidney and liver) was studied. It was found that after a 6-hour perfusion of the complex of organs the amount in the perfusion medium of such amino acids as histidine, lysine, alanine, considerably increased, whereas the amount of arginine, serine, aspartic acid, threonine with glutamine, isoleucine, proline, leucine and valine decreased as compared with their initial concentration. The dynamics of the amino acid medium composition during a 4-hour perfusion was studied in experiments with the isolated sternum. The concentration of alanine, lysine and histidine increased in the medium. At the same time there was seen a decrease in the concentration of serine, aspartic acid, isoleucine, tyrosine and phenyl-alanine.     

Metabolic Conversion of Amino Acids Loaded in the Vacuole of Chara australis Internodal Cells

Vacuoles of internodal cells of Chara australis (or Chara corallina) were loaded with a 10 millimolar amount of various amino acids by a perfusion method and incubated under continuous light. After 20 to 24 hours, the cell sap was collected, and free amino acids in it and the rest of the cell (cytoplasm) were analyzed. The only amino acid metabolized completely was alanine. About 40 to 80% of the aspartic acid, glutamine, serine, and glycine were metabolized, whereas less than 30% of the threonine, asparagine, isoasparagine, isoleucine, phenylalanine, γ-aminobutyric acid, lysine, and arginine were metabolized. The figure for glutamic acid fluctuated between 10 and 100%. The main metabolites of alanine were glutamine, glycine and ammonia, which accumulated in the vacuole. Alanine utilization was not affected by l-methionine-d,l-sulfoximine or azaserine, but was strongly inhibited by aminooxyacetate. The cell extract contained enough alanine aminotransferase activity to account for the rate of alanine metabolism.     

Amino Acid Concentrations in Rumen Fluid

Methods using dialysis or ultrafiltration are described for the collection of extracellular fluid in rumen contents for analysis of amino acids. Marked differences in the concentration of aspartic acid, glutamic acid, and alanine were found in samples of either diffusate or ultrafiltrate and in clarified acidified rumen liquor. Concentrations are given for aspartic acid, glutamic acid, alanine, glycine, γ-aminobutyric acid, valine, δ-aminovaleric acid, and leucine.     

Effect of provenance on free amino acid and chemical composition of Scots pine needles

Free amino acid (16 amino acids) and chemical composition (N, P, K, Mg, Ca, S, Fe, Mn, Cu, Zn) of Scots pine (Pinus sylvestris L.) needles were compared between six provenances in three different experimental areas. The main free amino acids in the needles were in the sequence of quantity; glutamic acid, glutamine, arginine and γ-aminobutyric acid. There were no significant differences in the concentrations of phenylalanine, γ-aminobutyric acid, methionine, proline and threonine in pine needles between the sites or between the provenances. Significant differences in the foliar concentrations of alanine and leucine were found between the sites and in the foliar concentrations of isoleucine, glutamine, glycine and tyrosine between the provenances. The concentrations of aspartic acid, glutamic acid, arginine and lysine were significantly affected by the sites and the provenances. The foliar nutrients, except copper, had statistically significant differences, both between the sites and between the provenances. Calcium did not differ between the provenances. This revised version was published online in June 2006 with corrections to the Cover Date.     

Morphogenesis and free amino acid composition of the ascomycete Sphaerostilbe repens as influenced by nitrogen and calcium

Abstract Sphaerostilbe repens utilizes nitrate and ammonium as nitrogen sources. Differentiation of mycelium into rhizomorphs and coremia was reduced in the presence of nitrate and completely inhibited in the absence of calcium. The most abundant free amino acids were, in decreasing order: alanine, glutamine, glutatomic acid, serine, aspartic acid, γ-aminobutyric acid, arginine and threonine. These compounds represented 90% of the total amino acid pool.
The free amino acid composition did not vary with cultural conditions although concentrations of individual amino acids differed. In ammonium-grown cells, γ-aminobutyric acid increased in concentration and glutamate, aspartate and alanine decreased. Calcium-deficient media reduced amino acid concentrations, especially of arginine and ornithine. Amino acid contents increased during the growth period and were higher in rhizomorphs than in vegetative mycelia.     

Changes in protein fractions and leucine-[14C] incorporation during Sorghum grain development

Incorporation of leucine and changes in different protein fractions have been studied during Sorghum grain development. Most of the label from the injected leucine-[¹⁴C] was found in glutelin and residue fraction towards later stages of maturity. The label in albumin, globulin and prolamin decreased with a concomitant increase in label in glutelin and residue proteins. The concentration of lysine, aspartic acid and glycine decreased while that of leucine, proline, alanine, tyrosine, phenylalanine, and cystine increased during grain development. Increase in serine, methionine, valine and isoleucine was only marginal. The proportion of glutamic acid was high at all stages of grain development. Glutelin fraction resolved into two peaks on gel chromatography, only one of which with higher MW was labelled, while in albumin both the peaks were found to be labelled. Tannin content also increased during grain development.     

Free alanine,aspartic acid,or glutamic acid reduce the glycation of human lens proteins

The amino acids lysine and glycine are reported to react with glucose at physiological pH and temperature and undergo non-enzymic glycation. Three other amino acids present in relatively larger amounts in the lens i.e. alanine, aspartic acid and glutamic acid were also found to undergo non-enzymic glycation as found by incorporation of uniformly labelled (U-[¹⁴C]) glucose into the amino acids. The glucose incorporation was 1.6 to 2.5% for alanine, 35 to 50% for aspartic acid and 2.3 to 3.3% for glutamic acid. Each amino acid of varying concentrations lowered the extent ofin vitro glycation of lens proteins significantly in glucose-treated homogenates of normal lens from humans. The decrease in glycation for alanine was between 32 and 69%, that for aspartate was between 18 and 74%, and for glutamate was between 52 to 74%. Decreased glycation was greater for higher concentrations of glucose. Scavenging of intracellular glucose and decreasing the extent of glycation of lens proteins could be the mechanism of action by which the amino acids alanine, aspartic acid and glutamic acid could exercise a beneficial effect on cataract and diabetic retinopathy.     

Gas chromatographic analysis of free amino acids in the hyaloplasm of the hypophysis, pineal gland, thyroid gland, spinal cord, thymus and lymph nodes of the cow

Studies of the qualitative and quantitative composition of free amino acids in the hyaloplasm of the hypophysis, pineal gland, thyroid gland, spinal cord, thymus and lymph nodes of the cow are described. The following findings are reported: the highest levels of alanine, valine, glycine, isoleucine, histidine, leucine, threonine, serine, phenylalanine, tyrosine and lysine are found in the thyroid gland, methionine and aspartic acid in the spinal cord, tryptophan and hydroxyproline in the pineal gland, and proline and glutamic acid in the thymus gland. The highest level by weight is that of glutamic acid in all tissues. The presence of α-aminobutyric acid combined with sarcosine and 4-aminoisobutyric acid with 2-AOA and citrulline with cystine was demonstrated. α-Aminoisobutyric acid and isovaline were found in the spinal cord.     

Free Amino Acid, Protein and Water Content Changes Associated with Seed Development in Araucaria angustifolia

The free amino acid, protein, water and dry matter contents were determined during the seed development of Araucaria angustifolia. Soluble and insoluble proteins in the mature seed represent 4.2 % of the fresh matter. The embryonic axis stored the greatest amount of soluble proteins, while cotyledons both with the embryonic axis showed the largest quantities of insoluble proteins in the mature seed. The greatest concentration of free amino acids was detected during the stage when cotyledons start to develop. Glutamic acid, aspartic acid, alanine and serine were predominant in the whole seed while arginine, lysine and γ-aminobutyric acid were present in great amounts only in cotyledons and embryonic axis. Although megagametophyte was important as a source of free amino acids, it was not the major protein storage organ in the mature seed. In the embryogenetic process, the rise of cotyledons is closely related to physiological and biochemical changes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Amino Acids from Heterodera glycines

Amino acids emitted and extracted from surface-sterilized larvae and adults of Heterodera glycines were identified by paper chromatography and quantitatively analyzed by column chromatography. Five amino acids (alanine, aspartic acid, glutamic acid, glycine and serine) were emitted by H. glycines larvae and eight others (asparagine, glutamine, leucine/isoleucine, lysine, methionine sulfoxide, threonine, tyrosine, valine/methionine) were found in extracts from crushed larvae.In addition to the amino acids emitted or extracted from larvae, four others were emitted by adults (γ-aminobutyric acid, histidine, phenylalanine, and proline). Four different amino acids (arginine, cystathionine, hydroxyproline, and ornithine) were found only in the extract from crushed adults. Greater quantities of alanine, aspartic acid and glycine were emitted than could be detected in nematode extracts suggesting selective emission.Subsamples of nematode populations were taken from growing plants 19, 26, 33, and 40 days after inoculation and extracted to determine whether changes in specific amino acid content correlated with aging. Proline content shifted most, increasing from 4.1% to 21.5% of the total amino acid complement from the 19th to the 40th days.     

Effect of dieldrin injection on the level of certain amino acids and some enzymes in rat brain

The present investigation revealed the effect of the organochlorine insecticide dieldrin at the dose level 0.25 LD50 at different time intervals on the concentration of 11 rat brain amino acids, on the activities of glutamic oxyacetic transaminase (GOT), glutamic pyruvic transaminase (GpT) and cholinesterase. The study was also extended to include the total protein content during the tested periods. The daily injection of dieldrin caused a marked decrease in the levels of glutamic acid, glutamine and taurine and an increase in the levels of aspartic acid, asparagine, GABA, glycine, lysine, serine, alanine and histidine. However, the maximal increase and decrease were recorded for most of the tested amino acids at the end of the tested period. The activity of the transaminases increased significantly. The recorded values of GOT were usually higher than GPT. Cholinesterase activity was inhibited thoroughly during all the experimental periods. Total protein content was decreased in the experiment; the minimal value was given 3 days after the injection.