The importance of dietary amino acids on the reproduction and longevity of adult Dacus oleae (Gmelin) (Diptera Tephritidae)

When the amino-acid mixture of an effective chemically defined diet was replaced by single amino acids, keeping the total nitrogen at the same level, the egg production of Dacus oleae was minimal with all the 19 amino acids tested. Male survival was adversely affected by the amino acids : alanine, aspartic acid, glutamic acid, glycine, hydroxyproline, lysine, serine and tyrosine, while female survival was shortened when the amino acids : glycine, hydroxyproline and lysine were added. The creation of amino-acid imbalances, by deleting the 19 amino acids individually, from the complete amino-acid mixture, showed that the amino acids : arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophane and valine were indispensable to the adult Dacus oleae flies, as far as egg production is concerned. Survival of the male flies was significantly shortened when the amino acids : alanine, hydroxyproline and tryptophane were omitted. Significant differences in longevity between males and females were scored, when the amino acids : alanine, aspartic acid, cystine, glycine and tryptophane, were omitted.     

Reproduction of bacteriophage T6 and T7 in auxotrophic mutants ofE. coli B

Summary Phage T₆ and T₇ did not reproduce in mutants ofE. coli auxotrophic for the amino acids methionine, leucine, serine, proline, histidine, tyrosine, phenylalanine and tryptophane unless these amino acids were present in the medium. Very small amounts of these auxotrophic factors (0.01 γ/ml) are able to support phage multiplication. Much care has to be taken to avoid impurities in the medium and to deplete the endogenous reserves of the host cells.     

Amino acid requirements for growth of the rabbit blastocyst in vitro

Ten amino acids, namely, arginine, histidine, lysine, tryptophane, methionine, phenylalanine, leucine, valine, threonine and serine were indispensable for growth of rabbit blastocysts in vitro; others were nonessential. Of all the essential amino acids, arginine and lysine were required in relatively high concentrations, 10^?2 M and 10^?3 M, respectively, for optimum growth. Complete omission of the non-essential amino acids from the medium markedly reduced blastocyst growth. Interaction between serine and glycine demonstrated a partial sparing action on serine by glycine, similar to that observed between methionine and cysteine. The amino acid composition of a culture medium capable of providing continuous and consistent growth of rabbit blastocysts in vitro is described.     

Speculations on the evolution of the genetic code II

An evolutionary scheme is postulated in which a primitive code, involving only guanine and cytosine, would code for glycine (GG), alanine (GC), arginine (CG) and proline (CC). From each of these amino acids and their codons, there evolves a family of related amino acids as the code expands. The four families are: (1)alanine valine, leucine, isoleucine, phenylalanine, tyrosine, methionine and tryptophane; (2)proline, threonine and serine; (3)arginine, lysine, and histidine; (4)glycine, serine, cysteine, glutamic acid, glutamine, aspartic acid and asparagine. Except for the glycine relation to glutamic acid and aspartic acid, all amino acids are related by chemical similarities in their side chains. Glycine not having a side chain would permit a more complex set of substitutions.     

Amino acid requirements for attachment and outgrowth of the mouse blastocyst in vitro

Arginine, cystine, histidine, leucine and threonine were needed for outgrowth of the mouse blastocyst in vitro. Omission of lysine, methionine, phenylalanine, tryptophane and tyrosine from the culture medium markedly reduced blastocyst outgrowth, but did not inhibit it completely; while omission of isolecine and valine reduced the extent of outgrowth only slightly. Blastocysts kept for seven days in a free-floating condition by omitting arginine and leucine from the medium, grew out when these amino acids were added. Such behavior may be analogous to delayed implantation in utero and suggests that the free amino acid content of the uterus could be an important factor in the control of implantation. Blastocysts delayed from implanting in the uterus by ovariectomy were activated to outgrowth in a complete medium, but the intracellular changes associated with outgrowth occurred more slowly than in undelayed blastocysts.     

Effects of natural amino acids and sugars on activity of infusiorian cyclases

Natural amino acids and sugars in unicellular eukaryotes are known to regulate adenylyl cyclase (AC) and guanylyl cyclase (GC) systems that control the most important cell processes. The goal of the present work consisted in study of effects of natural amino acids and sugars and some of their derivatives on AC and GC activities of infusoria Tetrahymena pyriformis and Dileptus anser. Methionine, arginine, lysine, and tryptamine stimulated basic AC activity of T. pyriformis, whereas alanine, tyramine, and cysteine decreased it. Methionine, glycine, alanine, thyrosine, arginine, and to the lesser degree tryptamine and histidine stimulated AC of D. anser. The GC activity of T. pyriformis rose in the presence of tryptamine, tryptophane, histidine, arginine, and lysine, whereas glycine and aspartic acid, on the contrary, decreased it. Tryptamine, tryptophan, leucine, glutamic acid, serine, histidine, and alanine stimulated the GC activity of D. anser. Glucose, fructose, and sucrose stimulated the basal AC activity of both infusorians and GC of T. pyriformis, with glucose and sucrose increasing AC of T. pyriformis twice, while that of D. anser 4.5 times. Lactose stimulated AC and GC of T. pyriformis and was inefficient with respect to the D. anser cyclases, whereas mannose and galactose did not affect the enzyme activities in both infusorians. The study of the chemotactic response of the infusorians to amino acids and sugars indicates that involved in realization of this response can be signaling pathways both dependent on and independent of cyclic nucleotides. Thus, it has been established for the first time that several amino acids and sugars affect functional activity of enzymes with cyclase activity of the infusorians T. pyriformis and D. anser. This confirms the hypothesis that at early stages of evolution the large specter of comparatively simple natural molecules has a hormone-like action.     

Isolation from Cigar Tobacco Leaves of Tetrahydroactinidiolide

Basic amino acids (lysine, histidine and arginine) accumulated in Saccharomyces cerevisiae vacuoles should be mobilized to cytosolic nitrogen metabolism under starvation. We found that the decrease of vacuolar basic amino acids in response to nitrogen starvation was impaired by the deletion of AVT4 gene encoding a vacuolar transporter. In addition, overexpression of AVT4 reduced the accumulation of basic amino acids in vacuoles under nutrient-rich condition. In contrast to AVT4, the deletion and overexpression of AVT3, which encodes the closest homologue of Avt4p, did not affect the contents of vacuolar basic amino acids. Consistent with these, arginine uptake into vacuolar membrane vesicles was decreased by Avt4p-, but not by Avt3p-overproduction, whereas various neutral amino acids were excreted from vacuolar membrane vesicles in a manner dependent on either Avt4p or Avt3p. These results suggest that Avt4p is a vacuolar amino acid exporter involving in the recycling of basic amino acids.     

Production of amino acids by free-living heterotrophic nitrogen-fixing bacteria

Summary Interest of microbial production of amino acids has been increased greatly since development of biotechnological methods. These methods represent a perspective way applied in a future large-scale manufacture of inexpensive amino acids. In this context, the isolation of producing organisms that may be exploited in the desing of alternative methods for the production of amino acids could be of primary importance.In this review we will describe the liberation of amino acids (methionine, lysine, arginine, tryptophane and glutamic acid) byAzotobacter andAzospirillum during growth in culture media with different carbon sources under diazotrophic and adiazotrophic conditions. These organisms may be useful in developing new methods for the industrial production of amino acids.     

Nutritional studies of some members of mucorales IV. 1. Sugars,amino- and organic acids of the mycelium

Summary and Conclusions The sugars and amino acids of the fungal mycelium of six species of the order Mucorales were determined with the use of two-dimensional as well as circular paper chromatography. A critical survey of the above conclusions revealed that aspartic acid, glutamic acid, glycine and serine and -alanine were found in either free and bound form. Glutamine and arginine were absent in bound form. Threonine, histidine, isoleucine and tryptophane were absent in the ethanol soluble fraction. The presence and absence of certain amino acids in these species are good subsidiary characters for distinguishing one of them from the other.In the majority of the species three sugars viz., glucose, fructose and sucrose were found. InM. indica andC. bertholletiae sucrose was absent. Amongst the organic acid only tartaric and malic acids were detected in all the organisms.     

Studies on aspergilli. VI. The utilization of amino acids in mixtures by some ascosporic members of the aspergillus nidulans group

Summary The utilization of certain amino acids when supplied in three different combinations, (a) glycine, serine, valine, histidine (b) methionine, valine, alanine, arginine (c) leucine, tryptophane, glutamic acid, aspartic acid, byA. nidulans (Eidam)Wint;A. rugulosus Thom andRaper;A. variecolor (Berk. andBr.)Thom andRaper;A. quadrilineatus Thom andRaper andA. violaceus Fennel andRaper was studied through circular partition chromatography. It was found that these Aspergilli which are so closely related morphologically exhibited different rate of assimilation of amino acids. Amino acids in mixtures were utilized better than when supplied singly. Although different species had their own preference to certain amino acids yet there was a simultaneous utilization of both good and poor amino acids.     

Amino-acid synthesis in adult Dacus oleae (Gmelin) (Diptera Tephritidae) determined with [U-14C] glucose

The ability of adult Dacus oleae for amino-acid synthesis from [U-14C] glucose was investigated. The relatively high specific activity radiometric measurements indicated that both sexes were able to synthesize the amino acids: alanine, aspartic acid, cystine, glutamic acid, glycine, hydroxyproline, proline and tyrosine; therefore, these amino acids are considered as nutritionally dispensable for D. oleae. On the other hand, the amino acids: arginine, histidine, leucine, isoleucine, lysine, methionine, phenylalanine, serine, threonine, and valine, showed a very low specific activity and therefore are considered as nutritionally indispensable. It was not possible to conclude about tryptophane, since the acid hydrolysis destroyed this amino acid.     

Meat meal in the diet of the early-weaned pig IV. The supplementation of diets with tryptophane,lysine and methionine

Two experiments were conducted with 72 pigs between 28 and 56 days of age to study the effect of tryptophane supplementation on their performance when fed on diets containing wheat and meat meal.In the first experiment, pigs were fed on a basal diet (Diet 1) or on the same diet supplemented with calcium dihydrogen phosphate (Diet 2), bone meal (Diet 3) or bone meal plus tryptophane (Diet 4), all to 3.1% calcium. The weight gains of the pigs (315 g day^?1) fed on Diet 3 were significantly lower than that of the pigs fed on the other three diets (363 g day^?1). The feed conversion ratios showed a similar trend. Diet 3 contained 0.16% tryptophane while the other diets contained 0.18–0.19% tryptophane. The crude protein, lysine and methionine contents of all diets were similar.In the second experiment, a basal diet containing meat meal and bone meal was supplemented with tryptophane, lysine plus methionine or all three amino acids. Feed intake was increased by all amino acid supplements. Weight gains were improved significantly (57%) by the addition of all three amino acids to the diets, but the improvements due to tryptophane alone (28%) or methionine plus lysine (35%) were not significant. Tryptophane supplementation alone or with lysine plus methionine increased the nitrogen retention of the pigs.It was concluded that the requirement for tryptophane of pigs between 28 and 56 days of age was greater than 0.16% of diets containing wheat and meat meal.     

P-aminohippurate accumulation in kidney cortex slices: stimulation by dicarboxylates, amino acids and their oxoanalogues.

The effect of various amino acids and oxoacids on the accumulation of PAH in rat kidney cortex slices was determined. The following compounds were found to increase the PAH tissue to medium ratio (T/MPAH): a) dicarboxylic acids: glutarate, 2-oxoglutarate and oxaloacetate, b) amino acids: glutamate, isoleucine, leucine, valine, methionine, tryptophane, histidine, threonine and glycine, c) monocarboxylates: hydroxymethionine, oxovaline, oxoisoleucine and oxoleucine. There were no marked concentration/effect differences to glycine, glutamate, glutarate and oxovaline. Ouabain inhibited T/MPAH only slightly, but abolished its increase by pyruvate, 2-oxoglutarate and histidine. Oxygen hyposaturation abolished the T/MPAH increase caused by 2-oxoglutarate, pyruvate, glutamate and histidine. It is concluded that various substrates stimulating the organic anion transport system (OATS) do so namely by improving the energy supply, although the direct participation of dicarboxylates in OATS could be of relevance namely in short-lasting variations.     

Repression of alkaline protease in salt-tolerant alkaliphilic <Emphasis Type="Italic">Streptomyces clavuligerus</Emphasis> strain Mit-1 under the influence of amino acids in minimal medium

A salt-tolerant alkaliphilic actinomycete (strain Mit-1) was isolated from Mithapur (Western Coast, Gujarat, India) and identified as Streptomyces clavuligerus. Based on 16S rRNA gene sequence (EU146061) homology, it was found to be related to Streptomyces sp. (AY641538.1). The strain secreted alkaline protease optimally at 5% NaCl and pH 9 during the early stationary phase and could utilize the amino acids methionine, alanine, leucine, phenylalanine, tyrosine, tryptophan, arginine, asparagine, histidine, and glutamic acid as the sole source of nitrogen. Above their threshold levels, these amino acids caused repression of alkaline protease production. Protease production with methionine (120 U/mL), histidine (140 U/mL), and aspartic acid (118 U/mL) was comparable to that with complex medium (130 U/mL). However, the production increased with an increasing number of different amino acids in the growth medium. Repression of protease production as influenced by the amino acids generated valuable information on enzyme synthesis in actinomycetes, as such data is scarce. Optimization of the conditions for enzyme production by actinomycetes in general, and in haloalkaliphilic actinomycetes in particular, appears to be an attractive proposition for biocatalysis.     

Quantitative analysis of histidine and cis and trans isomers of urocanic acid by high-performance liquid chromatography: a new assay method and its application

To elucidate the factors involved in dry skin and the skin damage caused by UV light, it is necessary to analyze small amounts of stratum corneum to determine amino acid contents. A new assay method for this purpose is described. Dabsylated amino acids including histidine and the cis and trans isomers of urocanic acid were analyzed quantitatively by high-performance liquid chromatography (HPLC), using a reversed-phase column. Histidine and the isomers of urocanic acid were separated from 36 other amino acids thought to be present in the extract of stratum corneum. In the presence of the 36 amino acids, standard calibration curves were obtained from 0.25 to 2.5 pmol/μl, for histidine and for both isomers of urocanic acid. The coefficients of variation for the reproducibility of the analysis at 1.0 pmol/μl were 3.8%, 2.9% and 2.5% for the cis and trans isomers of urocanic acid and for histidine, respectively. Amounts of 2 to 50 pmol of cis and trans isomers of urocanic acid and histidine in the stratum corneum were detected. The ratio of the cis to the trans isomer of urocanic acid in sunburned stratum corneum was more than three times that in normal stratum corneum. This method appears to be useful for the determination of small amounts of histidine and of the cis and trans isomers of urocanic acid in the stratum corneum.     

Proteolysis upon dehydration of yeasts saccharomyces cerevisiae

The effect of dehydration on proteolysis and activity of proteases A, B and C in the cells of baker's yeast Saccharomyces cerevisiae was investigated. It can be concluded, that under investigated conditions of yeast Saccharomyces cerevisiae drying a decrease of proteases activity takes place. In cells a limited proteolysis takes place which is indicated by an increase in amino nitrogen content and a decrease of tryptophane synthase activity. Adding the protease inhibitor to yeast suspension prevents decrease of tryptophane synthase activity upon dehydration.     

The amino acid transport systems of the autotrophically grown green alga Chlorella

The kinetic analysis of l-amino acid uptake by the green alga Chlorella revealed at least seven different uptake systems to be present in cells grown autotrophically with nitrate as nitrogen source. There is a ‘general system’ which transports most neutral and acidic amino acids, a system for short-chain neutral amino acids including proline, a system for basic amino acids including histidine, a special system for acidic amino acids, and specific systems for methionine, glutamine and threonine. The ‘general system’ is possibly the same as that which can be stimulated by incubation of cells in glucose plus ammonium (Sauer, N. (1984) Planta 161, 425–431). The incubation of Chlorella in glucose induces the increased synthesis of six amino acid uptake systems, namely the above-mentioned system for short-chain neutral amino acids, a threonine system, a methionine system, and a glutamine system. These results indicate that the uptake of l-amino acids by the green alga Chlorella is as complex as in other free-living organisms such as bacteria or yeast. The small number of amino acid uptake systems found in cells of higher plants, i.e. two or three, seems therefore to be a consequence of integration of the cells in a tissue supplying a relatively constant environment, and not a consequence of autotrophic growth on mineral carbon and mineral nitrogen.     

Age-related changes of muscle and plasma amino acids in healthy children

The aim of the study was to explore if changes in muscle and plasma amino acid concentrations developed during growth and differed from levels seen in adults. The gradient and concentrations of free amino acids in muscle and plasma were investigated in relation to age in metabolic healthy children. Plasma and specimens from the abdominal muscle were obtained during elective surgery. The children were grouped into three groups (group 1: < 1 year, n = 8; group 2: 1–4 years, n = 13 and group 3: 5–15 years, n = 15). A reference group of healthy adults (21–38 years, n = 22) was included in their comparisons and reflected specific differences between children and adults. In muscle the concentrations of 8 out of 19 amino acids analysed increased with age, namely taurine, aspartate, threonine, alanine, valine, isoleucine, leucine, histidine, as well as the total sums of branched chain amino acids (BCAA), basic amino acids (BAA) and total sum of amino acids (P < 0.05). In plasma the concentrations of threonine, glutamine, valine, cysteine, methionine, leucine, lysine, tryptophane, arginine, BCAA, BAA and the essential amino acids correlated with age (P < 0.05). These results indicate that there is an age dependency of the amino acid pattern in skeletal muscle and plasma during growth.     

Nitrogen deficiency induced changes of free amino acids and coumarin contents in the leaves of Matricaria chamomilla

Through o-hydroxycinnamic acids, the biosynthesis of coumarins is connected with aromatic amino acid metabolism and nitrogen uptake. Therefore the quantitative changes in levels of some free amino acids and coumarins (herniarin and its glucosidic precursors (Z) - and (E)-2-β-D-glucopyranosyloxy-4-methoxycinnamic acids; umbelliferone) in the leaf rosettes of chamomile (Matricaria chamomilla L.) subjected to nitrogen deficiency were studied. Nitrogen content decreased in the leaf rosettes and in the roots of N-deficient plants during the course of the experiment, but these plants produced significantly higher root biomass. Among secondary metabolites, the sum of 2-β-D-glucopyranosyloxy-4-methoxycinnamic acids increased sharply, herniarin increased slowly and the content of umbelliferone was low in N-deficient plants. We have concluded that nitrogen deficiency is not an inducing factor for stress accumulation of herniarin and umbelliferone. A decrease in levels of all detected amino acids, besides histidine, was found. Within aromatic amino acids, tyrosine was the most abundant. The content of free phenylalanine was significantly lower in both, control and N-deficient plants when compared to the content of tyrosine. In this view, the increase of herniarin glucosidic precursors is apparently due to enhancing phenylalanine ammonia-lyase activity under nitrogen deficiency and nitrogen-free carbon skeletons are shunted in to the phenylpropanoid metabolism, including biosynthesis of (Z)-and (E)-2-β-D-glucopyranosyloxy-4-methoxycinnamic acids.     

Vba2p,A Vacuolar Membrane Protein Involved in Basic Amino Acid Transport in Schizosaccharomyces pombe

A recent study filling the gap in the genome sequence in the left arm of chromosome 2 of Schizosaccharomyces pombe revealed a homolog of budding yeast Vba2p, a vacuolar transporter of basic amino acids. GFP-tagged Vba2p in fission yeast was localized to the vacuolar membrane. Upon disruption of vba2, the uptake of several amino acids, including lysine, histidine, and arginine, was impaired. A transient increase in lysine uptake under nitrogen starvation was lowered by this mutation. These findings suggest that Vba2p is involved in basic amino acid transport in S. pombe under diverse conditions.