The modulating effect of amino acids on an organotypic culture of lymphoid tissue

The effect of 20 essential and nonessential L-amino acids on the dynamics of development of spleen explants from 1- and 21-day-old rats on an organotypic tissue culture was studied. The hydrophilic amino acids with a higher molecular mass (asparagine, lysine, arginine, and glutamic acid) induced an inhibitory effect on the growth zone of explants of immature tissue from 1-day-old animals and an opposite, stimulating effect on the mature spleen tissue of 21-day-old rats. An immunohistochemical analysis revealed a reciprocal correlation between the expression of the proapoptotic protein p53 and the cell proliferation upon the action of lysine, asparagine, and glutamic acid. The role of polar amino acids in the modulation of cell proliferation and apoptosis in dependence on the period of ontogenesis was determined. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2006, vol. 32, no. 3; see also http://www.maik.ru.     

Effect of amino acids on cell proliferation and protein p53 expression in organotypic culture of lymphoid tissue from neonatal rats

The effect of the larger molecular weight l-amino acids on the development of spleen explants from 1- and 21-day rats in organotypic tissue culture was studied. The amino acids asparagine, lysine, arginine, and glutamic acid inhibited the growth zone of explants of immature tissue from 1-day animals but had an opposite, stimulating, effect on mature spleen tissue of 21-day rats. Immunohistochemical analysis revealed a reciprocal correlation between the expression of the proapoptotic protein, p53, and T-cell proliferation in response to lysine, asparagine, and glutamic acid. Interestingly only arginine reduced the area of p53 expression both in explants of mature and immature spleen tissue. The ability of arginine to reduce p53 expression can be suggested as one of the mechanisms of the tumor growth stimulation.     

The effect of the coded amino acids on meso- and ectodermal tissue development in organotypic culture

The effect of L-amino acids was investigated in organotypic tissue culture ofmesodermal tissue (spleen, myocardium) and ectodermal tissue (brain cortex) in mature rats. The low hydrophobic amino acids: asparagine, hystidine, serine, lysine, arginine and glutamine acid, induced the proliferation stimulation. The high hydrophobic amino acids had both the apoptose effect (spleen) and no effect at all (myocardium). The proliferation stimulation occurred in the ectodermal tissue under the effect of the high hydrophobic amino acids (asparagines acid, valine, threonine, methionine, leucine, isoleucine), whereas the low hydrophobic amino acids had no effect on the nervous tissue development. The combination of two amino acids one of which stimulated and another one inhibited the explant growth zone (or was not active in myocardium) lead to an increase of the stimulatory effect in meso- and ectodermal tissue. The amino acid modulated properties can be taken in consideration in synthesis of new regulatory peptides.     

The modulating action of amino acids upon development in an organotypic culture

The effect of L-amino acids in concentration 0.05 ng/ml was investigated in organotypic tissue culture of spleen, liver and brain cortex at the age of 1 and 21 days. The high molecular and low hydrophobic amino acids: asparagin, lysine, arginine, and glutamine, are active inducing both a less intensive growth zone in explants of all three tissue types in 1-day old rats and more intensive growth zone in spleen, liver explants in 21-day rats as compared to control. Another group of low molecular and high hydrophobic amino acids is active inducing a more intensive growth zone in brain cortex explant in 21-day rats, as compared to control. The data obtained suggest a modulating role of amino acids in the tissues at different stages of maturation.     

The involvement of amino acids in latex lipid synthesis in Euphorbia lathyris seedlings

The breakdown of triglycerides and proteins in the endosperm of Euphorbia lathyris was assayed in a 14 day germination period. Six days after germination, the average daily production was 2.7 μmol of amino acids. Arginine, glutamine, asparagine and glutamic acid accounted for 53% of the total amino acids. Excised cotyledons with 1 cm hypocotyls were used for amino acid uptake and their involvement in terpenoid synthesis was studied. Glutamine and aspartate were hardly involved in apolar lipid synthesis. Leucine, isoleucine, valine and threonine were mainly incorporated into the triterpenes in the laticifers. Alanine and serine were also involved in phytosterol synthesis in the adjacent tissue. In the 14 day germination period, ca3% of the daily yield of latex triterpenes may be synthesized from a variety of amino acids.     

Variations in the content of free and bound amino acids during dormancy and the first cell cycle in Helianthus tuberosus tuber explants

Abstract

Qualitative and quantitative analysis of free and bound amino acids and amides during dormancy and the most important phases of the first cell cycle was carried out in tubers of Helianthus tuberosus.

In the dormant tuber arginine was confirmed to be the most abundant amino acid. A high amount of asparagine was also present; on the contrary glutamine was found in very low concentrations. During the progression of dormancy, all the free amino acids and amides declined while aspartic and glutamic acid increased.

During the G₁ phase of the first cell cycle induced by 2,4-D, all the free amino acids and amides decreased with the exception of glutamic acid.

At 18, 20, 24 h of activation with 2,4-D, corresponding to the S phase and the beginning of mitosis, bound amino acids were also determined. In these phases of the cell cycle they increased reaching a maximum at 20 h; on the other hand the free amino acid and amide content, especially aspartic acid, asparagine and arginine, decreased with the exception of glutamic acid, alanine and phenylalanine.     

The effect of mono‐amino acids on larval settlement of the barnacle,Balanus amphitrite Darwin

Settlement of barnacle larvae is believed to be induced by the chemical cues present in their surrounding environment. Here, an investigation was carried out on the effects of sixteen different mono‐amino acids with acidic, basic, uncharged polar and nonpolar side chains, and GABA on larval settlement of the barnacle, Balanus amphitrite. Settlement inducing activity by nine mono‐amino acids, viz. asparagine, glutamine, tyrosine, serine, glycine, tryptophan, leucine, isoleucine and valine (but not phenylalanine) with uncharged polar and nonpolar side chains was observed. Of these, the most active mono‐amino acids were serine, leucine and isoleucine, which were effective at a threshhold of 1.0 × 10^‐7 M. On the other hand, aspartic acid, glutamic acid, GABA, and the basic mono‐amino acids lysine, arginine and histidine did not have any inducing effect. These results suggest that uncharged polar and non‐polar end group of the amino acid chain play an important role in inducing the settlement process in cyprids.     

Heterogeneous elevation of amino acid transport rates in pantothenate-and lipid-deficient Lactobacillus plantarum

The effect of a pantothenic acid deficiency in Lactobacillus plantarum on the initial rate of amino acid transport was investigated. Although the steady-state accumulation capacity for all amino acids was markedly reduced in pantothenate-deficient cells, initial rates of uptake either were not changed (asparagine, alanine, lysine) or were increased (glutamic acid, aspartic acid, leucine). The findings suggest that a reduction in membrane lipid content heterogeneously affects the operation and/or synthesis of amino acid transport catalysts.     

Changes in accumulation of seed nitrogen compounds in maize under conditions of sulphur deficiency

Maize ( Zea mays L., hybrid INRA 260) was grown in the greenhouse with mineral nutrition of different sulphate concentrations. Mature seeds from these plants were compared for their free amino acid and protein N forms. For the most S-deficient sample, the Asx (asparagine + aspartic acid) content increased by 30% as compared with control, while methionine and cysteine decreased (by 25 and 30%, respectively), as well as glycine, lysine, histidine, arginine and tryptophan. In seeds lowest in S the non-protein N to total N ratio was 77% higher than in the control. Free asparagine dominated in starved seeds (50 mol % of total free amino acids) and was ten-fold more concentrated than in the control, where proline was the predominant free amino acid. Thus the Asx of non-protein N reached 28% of the total mol Asx of the whole starved seed. Altered S nutrition had virtually no effect on the amino acid composition of the main protein fractions, but it significantly changed their ratios. Zeins, which are poor in S-containing amino acids, showed 25% higher level than in seeds supplied with normal S. As a counterbalance, two glutelin subfractions rich in S-containing amino acids, decreased by 36–71% under limiting S nutrition.
It is concluded that the plant reacts against S deficiency by modifying its N metabolism. Significant accumulation occurred of free asparagine, which is the main form of N transportation. The biosynthesis of seed storage protein occurred through the accumulation of the highest possible protein quantity allowed by the available S-containing amino acids, i.e. proteins low in S-containing amino acids were preferentially synthesized.     

Utilization and requirements of amino acids by a cell line derived from the butterfly Papilio xuthus

The media, in which a butterfly cell line (Px 58), derived from pharate adult ovaries of Papilio xuthus cultured for 8 days, were analysed to examine the changes in free amino acids in the medium during cultivation. Beta-alanine, arginine, glycine, histidine, lysine, phenylalanine, proline, serine, and tryptophan did not change markedly. Asparagine, aspartic acid, cystine, glutamine, isoleucine, leucine, methionine, threonine, tyrosine, and valine decreased to some extent with culturing. Alpha-alanine increased markedly, and glutamic acid did so to a lesser extent. Requirements of amino acids by the cell line were examined by deleting amino acids one at a time. Deletion of alpha-alanine, beta-alanine, asparagine, glutamic acid, glycine, and phenylalanine did not cause deterioration of the cell. These amino acids were thought to be non-essential or required only a little. Deletion of other amino acids impaired the cell growth severely. These amino acids would appear to be essential for growth of the Px 58 cell line.     

Influence d'un choc osmotique sur la composition des feuilles de cotonnier en acides amines libres

The effect of water stress on the free amino acids in cotton leaves has been investigated. The water deficit, obtained by lowering of osmotic potential through the use of polyethylene glycol (PEG-600) as the osmotic agent, induces an accumulation of free amino acids.Significant modifications in the composition of this fraction are observed. The major differences from treated and untreated leaves are in the levels of γ-aminobutyric acid, asparagine, proline, and glutamic acid and its amide.     

Free amino acids in some sponges

Most invertebrates, particularly those of marine origin, have relatively high concentrations of free amino acids which are considered an important constituent of their osmoregulatory mechanisms [1]. Very little information is available on the free amino acid distribution in Porifera [2,3]. Common amino acids in some sponges were recognised by paper chromatography by Inskip and Cassidy [4] and Ackermann et al. [5,6] included a few sponges in their survey of the occurence of nitrogen compounds in marine invertebrates. More recently Bergquist and Hartman [7] surveyed semiquantitatively the distribution of free amino acids in several sponges. In the present paper we report on the amino acid composition of 12 species of sponges belonging to the class Demospongiae as a part of a study on the metabolites of Porifera [8]. Fresh sponges were extracted with aqueous ethanol. The organic solvent was removed and the aqueous solution, after removal of the ether soluble compounds, was separated into cationic, anionic and neutral fractions by ion-exchange chromatography. The cation fraction was analysed for amino acids using an automatic amino acid analyser. The results, which are presented in Table 1, show that all species of sponges examined have a similar composition in common amino acids. Glycine almost always appears as the dominant protein amino acid, followed by high concentrations of alanine and glutamic acid, whereas relatively lower concentrations of basic amino acids are present. In Axinella cannabina, Chondrosia reniformis, Chondrilla nucula, Cliona viridis and Hymeniacidon sanguinea, glycine represents more than 77% of the total amino acids. The high percentage of free glycine (90.4%) in Chondrosia reniformis is noteworthy. The anionic and the neutral fractions were examined for sulfur-containing amino acids using PC. Taurine (Table 2) was detected in all the Porifera examined; this is in agreement with previous observations [5–7]. N-Methyltaurine was identified in some of the species examined, whereas neither N,N-dimethyltaurine nor N,N,N-trimethyltaurine were found.     

Stimulation of Lysine Decarboxylase Production in Escherichia coli by Amino Acids and Peptides

A commercial hydrolysate of casein stimulated production of lysine decarboxylase (EC 4.1.1.18) by Escherichia coli B. Cellulose and gel chromatography of this hydrolysate yielded peptides which were variably effective in this stimulation. Replacement of individual, stimulatory peptides by equivalent amino acids duplicated the enzyme levels attained with those peptides. There was no indication of specific stimulation by any peptide. The peptides were probably taken up by the oligopeptide transport system of E. coli and hydrolyzed intracellularly by peptidases to their constituent amino acids for use in enzyme synthesis. Single omission of amino acids from mixtures was used to screen them for their relative lysine decarboxylase stimulating abilities. Over 100 different mixtures were evaluated in establishing the total amino acid requirements for maximal synthesis of lysine decarboxylase by E. coli B. A mixture containing all of the common amino acids except glutamic acid, aspartic acid, and alanine increased lysine decarboxylase threefold over an equivalent weight of casein hydrolysate. The nine most stimulatory amino acids were methionine, arginine, cystine, leucine, isoleucine, glutamine, threonine, tyrosine, and asparagine. Methionine and arginine quantitatively were the most important. A mixture of these nine was 87% as effective as the complete mixture. Several amino acids were inhibitory at moderate concentrations, and alanine (2.53 mM) was the most effective. Added pyridoxine increased lysine decarboxylase activity 30%, whereas other B vitamins and cyclic adenosine 5′-monophosphate had no effect.     

A comparison of amide and ureide nitrogen sources in tissue culture of tree legume Prosopis alba clone B2 V50

The effects of medium nitrogen sources on the recalcitrant nature of Prosopis alba clone B2V50 in tissue culture were compared involving shoot development using axillary bud explants from 2 to 4-year-old greenhouse-grown trees. A significant difference (P<0.05) was found between the amino acids aspartic acid and glutamic acid and their corresponding amide-containing compounds asparagine and glutamine. A comparison between amide and ureide nitrogen sources showed that allantoin, a ureide, was an acceptable replacement for asparagine or glutamine. Allantoin, asparagine, and glutamine could be used as the sole nitrogen sources. Allantoin at a concentration of 20 mM was adopted for use in future research. Although shoots were consistently induced, all explants showed complete shoot-tip necrosis after 12 weeks of in vitro culture.     

相思子属三种药材中的氨基酸分析比较

利用全自动氨基酸分析仪和高效液相色谱仪分析比较相思子属三种药材中氨基酸成分及含量。结果9个样品都检测出17种氨基酸和2种色氨酸衍生物。结论:不同样品中的氨基酸含量有所差异,但其中门冬氨酸、谷氨酸、亮氨酸和赖氨酸的含量相对较高。     

Protein and free amino acids in a high lysine maize double mutant

A comparative study of free amino acids and protein fractions of normal with a double mutant (su₁ o₂) was made, during endosperm development in segregating ears of a maize synthetic. Zein content showed striking differences in the two genotypes, being 7.7 and 6 times greater in the normal endosperm at 24 and 47 days after pollination respectively. This observed decrease in zein synthesis, coded by sugary-1/opaque-2 genes, causes an accumulation of alanine, glutamic and aspartic acids, glutamine and asparagine in the high lysine endosperm mutant.     

Plasma amino acids in four models of experimental liver injury in rats

Summary We studied the plasma amino acid profiles in four models of hepatic injury in rats. In partially hepatectomized rats (65% of liver was removed) we observed significant increase of aromatic amino acids (AAA; i.e. tyrosine and phenylalanine), taurine, aspartate, threonine, serine, asparagine, methionine, ornithine and histidine. Branched-chain amino acids (BCAA; i.e. valine, leucine and isoleucine) concentrations were unchanged. In ischemic and carbon tetrachloride acute liver damage we observed extreme elevation of most of amino acids (BCAA included) and very low concentration of arginine. In carbon tetrachloride induced liver cirrhosis we observed increased levels of AAA, aspartate, asparagine, methionine, ornithine and histidine and decrease of BCAA, threonine and cystine. BCAA/AAA ratio decreased significantly in partially hepatectomized and cirrhotic rats and was unchanged in ischemic and acute carbon tetrachloride liver damage. We conclude that a high increase of most of amino acids is characteristic of fulminant hepatic necrosis; decreased BCAA/AAA ratio is characteristic of liver cirrhosis; and decrease of BCAA/AAA ratio may not be used as an indicator of the severity of hepatic parenchymal damage.Abbreviations BCAA branched-chain amino acids (i.e. valine, leucine and isoleucine) - AAA aromatic amino acids (i.e. tyrosine and phenylalanine)     

Amino-acid profiles in red algae

Free protein amino acids have been quantitatively determined in 30 red algae. In most of the species, aspartic acid (asparagine), glutamic acid (glutamine), alanine, glycine and serine dominate, while massive accumulation of proline (up to 80·5%) was observed in six species, all belonging to the family Rhodomelaceae.     

某些内科系统疾病患者血浆游离氨基酸的变化及意义

为了解某些内科系统疾病的血氨基酸代谢特点。测定１７０例９种内科系统急慢性疾病患者血浆游离氨基酸浓度,并分别与５８例健康人血浆氨基酸浓度作对比分析。９种疾病的血浆胱氨基酸浓度不同程度升高,以尿毒症病人最为显著,炎症性病人血浆苯丙、蛋、赖氨酸和苯丙／酪比值显著升高,丙、组、精、脯氨酸和支／芳比值显著降低;糖尿病和甲亢病人血浆总游离氨基酸、谷、丙、酪、赖和支链氨酸显著升高;糠尿病病人支／芳比值显著升高,表明不同疾病的血氨基酸浓度有特征性变化,炎症是导致血氨基酸代谢紊乱的重要因素