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Academic literature on the topic 'Amino acids – Biosynthesis'

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Published: 4 June 2021
Last updated: 6 September 2023

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Journal articles on the topic "Amino acids – Biosynthesis"

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Velíšek, J., and K. Cejpek. "Biosynthesis of food constituents: Amino acids. 3. Modified proteinogenic amino acids – a review." Czech Journal of Food Sciences 24, No. 2 (November 9, 2011): 59–61. http://dx.doi.org/10.17221/3300-cjfs.

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This review article gives a survey of principal pathways that lead to the biosynthesis of the modified principal proteinogenic amino acids, i.e. cystine, 4-hydroxyproline, 5-hydroxylysine, 3-methylhistidine, and O-phosphoserine. Except the proteinogenic amino acids, peptides and proteins often contain several unusual amino acids arising by specific modifications (e.g. oxidation or esterification) of amino acid residues present in the already synthesised polypeptide chain. The post-translational products include, e.g., the oxidation of the thiol groups of two cysteine residues to form a disulfide bridge (cystine), thus allowing cross-linking of polypeptide chains; the hydroxylation of proline to 4-hydroxyproline and of lysine to 5-hydroxylysine; N-methylation of histidine to 3-methylhistidine; and the phosphorylation of serine to O-phosphoserine. There also exist several other modified proteinogenic amino acids that are of minor significance to foods.    
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Velíšek, J., R. Kubec, and K. Cejpek. "Biosynthesis of food constituents: Amino acids: 4. Non-protein amino acids – a review." Czech Journal of Food Sciences 24, No. 3 (November 12, 2011): 93–109. http://dx.doi.org/10.17221/3304-cjfs.

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This review article gives a brief survey of the principal pathways that lead to the biosynthesis of the most important non-protein amino acids occurring in foods and feeds. These amino acids have been divided into the following groups: 3-amino acids and 4-amino acids, N-substituted amino acids, alicyclic amino acids, hydroxyamino acids, sulfur-containing amino acids, basic amino acids, and taurine.  
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Hochuli, Michel, Heiko Patzelt, Dieter Oesterhelt, Kurt Wüthrich, and Thomas Szyperski. "Amino Acid Biosynthesis in the Halophilic ArchaeonHaloarcula hispanica." Journal of Bacteriology 181, no. 10 (May 15, 1999): 3226–37. http://dx.doi.org/10.1128/jb.181.10.3226-3237.1999.

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ABSTRACT Biosynthesis of proteinogenic amino acids in the extremely halophilic archaeon Haloarcula hispanica was explored by using biosynthetically directed fractional 13C labeling with a mixture of 90% unlabeled and 10% uniformly13C-labeled glycerol. The resulting13C-labeling patterns in the amino acids were analyzed by two-dimensional 13C,1H correlation spectroscopy. The experimental data provided evidence for a split pathway for isoleucine biosynthesis, with 56% of the total Ile originating from threonine and pyruvate via the threonine pathway and 44% originating from pyruvate and acetyl coenzyme A via the pyruvate pathway. In addition, the diaminopimelate pathway involving diaminopimelate dehydrogenase was shown to lead to lysine biosynthesis and an analysis of the 13C-labeling pattern in tyrosine indicated novel biosynthetic pathways that have so far not been further characterized. For the 17 other proteinogenic amino acids, the data were consistent with data for commonly found biosynthetic pathways. A comparison of our data with the amino acid metabolisms of eucarya and bacteria supports the theory that pathways for synthesis of proteinogenic amino acids were established before ancient cells diverged into archaea, bacteria, and eucarya.
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Yang, Jianchang, Yujiao Zhou, and Yi Jiang. "Amino Acids in Rice Grains and Their Regulation by Polyamines and Phytohormones." Plants 11, no. 12 (June 15, 2022): 1581. http://dx.doi.org/10.3390/plants11121581.

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Rice is one of the most important food crops in the world, and amino acids in rice grains are major nutrition sources for the people in countries where rice is the staple food. Phytohormones and plant growth regulators play vital roles in regulating the biosynthesis of amino acids in plants. This paper reviewed the content and compositions of amino acids and their distribution in different parts of ripe rice grains, and the biosynthesis and metabolism of amino acids and their regulation by polyamines (PAs) and phytohormones in filling grains, with a focus on the roles of higher PAs (spermidine and spermine), ethylene, and brassinosteroids (BRs) in this regulation. Recent studies have shown that higher PAs and BRs (24-epibrassinolide and 28-homobrassinolide) play positive roles in mediating the biosynthesis of amino acids in rice grains, mainly by enhancing the activities of the enzymes involved in amino acid biosynthesis and sucrose-to-starch conversion and maintaining redox homeostasis. In contrast, ethylene may impede amino acid biosynthesis by inhibiting the activities of the enzymes involved in amino acid biosynthesis and elevating reactive oxygen species. Further research is needed to unravel the temporal and spatial distribution characteristics of the content and compositions of amino acids in the filling grain and their relationship with the content and compositions of amino acids in different parts of a ripe grain, to elucidate the cross-talk between or among phytohormones in mediating the anabolism of amino acids, and to establish the regulation techniques for promoting the biosynthesis of amino acids in rice grains.
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Velíšek, J., and K. Cejpek. "Biosynthesis of food constituents: Amino acids: 1. The glutamic acid and aspartic acid groups – a review." Czech Journal of Food Sciences 24, No. 1 (November 9, 2011): 1–10. http://dx.doi.org/10.17221/3287-cjfs.

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This review article gives a survey of principal pathways that lead to the biosynthesis of the proteinogenic amino acids of the glutamic acid group (glutamic acid, glutamine, proline, arginine) and aspartic acid group (aspartic acid, asparagine, threonine, methionine, lysine, isoleucine) starting with oxaloacetic acid from the citric acid cycle. There is an extensive use of reaction schemes, sequences, and mechanisms with the enzymes involved and detailed explanations using sound chemical principles and mechanisms.
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FITZGERALD, Lisa M., and Alina M. SZMANT. "Biosynthesis of ‘essential’ amino acids by scleractinian corals." Biochemical Journal 322, no. 1 (February 15, 1997): 213–21. http://dx.doi.org/10.1042/bj3220213.

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Animals rely on their diet for amino acids that they are incapable either of synthesizing or of synthesizing in sufficient quantities to meet metabolic needs. These are the so-called ‘essential amino acids’. This set of amino acids is similar among the vertebrates and many of the invertebrates. Previously, no information was available for amino acid synthesis by the most primitive invertebrates, the Cnidaria. The purpose of this study was to examine amino acid synthesis by representative cnidarians within the Order Scleractinia. Three species of zooxanthellate reef coral, Montastraea faveolata, Acropora cervicornis and Porites divaricata, and two species of non-zooxanthellate coral, Tubastrea coccinea and Astrangia poculata, were incubated with 14C-labelled glucose or with the 14C-labelled amino acids glutamic acid, lysine or valine. Radiolabel tracer was followed into protein amino acids. A total of 17 amino acids, including hydroxyproline, were distinguishable by the techniques used. Of these, only threonine was not found radiolabelled in any of the samples. We could not detect tryptophan or cysteine, nor distinguish between the amino acid pairs glutamic acid and glutamine, or aspartic acid and asparagine. Eight amino acids normally considered essential for animals were made by the five corals tested, although some of them were made only in small quantities. These eight amino acids are valine, isoleucine, leucine, tyrosine, phenylalanine histidine, methionine and lysine. The ability of cnidarians to synthesize these amino acids could be yet another indicator of a separate evolutionary history of the cnidarians from the rest of the Metazoa.
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Lauzier, Annie, Claudia Goyer, Luc Ruest, Ryszard Brzezinski, Don L. Crawford, and Carole Beaulieu. "Effect of amino acids on thaxtomin A biosynthesis by Streptomyces scabies." Canadian Journal of Microbiology 48, no. 4 (April 1, 2002): 359–64. http://dx.doi.org/10.1139/w02-031.

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The regulatory effect of amino acids on the production of thaxtomin A, a phytotoxin produced by Streptomyces scabies, was investigated. Tryptophan had an important inhibitory effect on the toxin biosynthesis in all five strains of S. scabies tested. Two other aromatic amino acids (tyrosine and phenylalanine) also inhibited thaxtomin A biosynthesis, while aliphatic amino acids did not cause an important decline in thaxtomin A production. Methylation of tryptophan prevented or reduced the inhibitory effect on thaxtomin A biosynthesis. In spite of the inhibitory action of tryptophan and phenylalanine on thaxtomin A production, incorporation of these radiolabeled molecules into thaxtomin A confirmed that they are metabolic precursors for the biosynthesis of the phytotoxin.Key words: thaxtomin A, phytotoxin, Streptomyces scabies, common scab, nitroaromatic compounds, amino acids.
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Bröer, Stefan, and Angelika Bröer. "Amino acid homeostasis and signalling in mammalian cells and organisms." Biochemical Journal 474, no. 12 (May 25, 2017): 1935–63. http://dx.doi.org/10.1042/bcj20160822.

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Cells have a constant turnover of proteins that recycle most amino acids over time. Net loss is mainly due to amino acid oxidation. Homeostasis is achieved through exchange of essential amino acids with non-essential amino acids and the transfer of amino groups from oxidised amino acids to amino acid biosynthesis. This homeostatic condition is maintained through an active mTORC1 complex. Under amino acid depletion, mTORC1 is inactivated. This increases the breakdown of cellular proteins through autophagy and reduces protein biosynthesis. The general control non-derepressable 2/ATF4 pathway may be activated in addition, resulting in transcription of genes involved in amino acid transport and biosynthesis of non-essential amino acids. Metabolism is autoregulated to minimise oxidation of amino acids. Systemic amino acid levels are also tightly regulated. Food intake briefly increases plasma amino acid levels, which stimulates insulin release and mTOR-dependent protein synthesis in muscle. Excess amino acids are oxidised, resulting in increased urea production. Short-term fasting does not result in depletion of plasma amino acids due to reduced protein synthesis and the onset of autophagy. Owing to the fact that half of all amino acids are essential, reduction in protein synthesis and amino acid oxidation are the only two measures to reduce amino acid demand. Long-term malnutrition causes depletion of plasma amino acids. The CNS appears to generate a protein-specific response upon amino acid depletion, resulting in avoidance of an inadequate diet. High protein levels, in contrast, contribute together with other nutrients to a reduction in food intake.
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Cortez-Espinosa, Nancy, Judit A. Aviña-Verduzco, Enrique Ramírez-Chávez, Jorge Molina-Torres, and Patricia Ríos-Chávez. "Valine and Phenylalanine as Precursors in the Biosynthesis of Alkamides in Acmella Radicans." Natural Product Communications 6, no. 6 (June 2011): 1934578X1100600. http://dx.doi.org/10.1177/1934578x1100600625.

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Acmella radicans (Asteraceae) produces at least seven alkamides, most with either an isobutyl- or phenylethyl group as the amine moiety. These moieties suggest that the amino acids valine and phenylalanine are the biosynthetic precursors of these alkamides. On the basis of labeled feeding experiments using either L-[2H8]valine or L-[2H8]phenylalanine we present evidence for the involvement of these two amino acids in the biosynthesis of (2 E,6 Z,8 E)- N-isobutyl-2,6,8-decatrienamide (affinin) (1), (2 Z,4 E)- N-(2-phenylethyl)-2,4-octadienamide (2), (2 E)- N-(2-phenylethyl)-nona-2-en-6,8-diynamide (3), and 3-phenyl- N-(2-phenylethyl)-2-propenamide (4). Alkamides were isolated from young A. radicans plants and analyzed by gas chromatography-mass spectrometry (GC-MS). Additionally, in cell free in vitro experiments based on isobutyl and phenylethylamide biosynthesis, using a colorimetric assay and GC-MS, valine and phenylalanine decarboxylase activities were assayed in the soluble extract of A. radicans leaves.
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Sisido, Masahiko. "Biosynthesis of Proteins Containing Nonnatural Amino Acids." Kobunshi 43, no. 9 (1994): 632–33. http://dx.doi.org/10.1295/kobunshi.43.632.

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Dissertations / Theses on the topic "Amino acids – Biosynthesis"

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Waluk, Dominik Paweł. "Biosynthesis and physiological functions of N-acyl amino acids." Doctoral thesis, Stockholms universitet, Institutionen för genetik, mikrobiologi och toxikologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-75766.

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N-acyl amino acids are lipid signalling molecules that have recently been identified in biological systems. These lipids are structurally related to the endocannabinoids, although they do not activate cannabinoid receptors. In 2001, N-arachidonoyl glycine was the first signalling lipid in this group to be identified in bovine and rat brain and since then, about 50 novel N-acyl amino acids have been identified in mammalian systems. These N-acyl amino acids are involved in regulating pain processes, are anti-inflammatory and regulate body temperature, but the metabolic pathways for production and metabolism remain poorly understood. This thesis focussed on the identification of pathways for production and regulation of N-acyl amino acids, in particular N-acyl glycines, and in identifying physiological functions for N-acyl amino acids (particularly N-acyl taurines). Our results identified an enzymatic pathway for production of N-acyl glycines in human and we identified that the human glycine N-acyltransferase-like 2 (hGLYATL2) conjugates (amidates) medium- and long-chain, saturated and unsaturated acyl-CoAs with glycine, to produce N-acyl glycines, with the preferential production of N-oleoyl glycine. Furthermore, we have characterized two other members of the gene family of glycine N-acyltransferases (GLYATs) in human, the hGLYATL1 and hGLYATL3 that may be involved in the production of N-acyl amino acids. As N-acyl glycines are bioactive signalling molecules, it is likely their production requires a rapid on/off switch. The post-translational modification of proteins can result in enzyme regulation, without the need for transcriptional regulation. We have identified that hGLYATL2 is regulated by acetylation/deacetylation on lysine 19, and using mutation analysis, we show that deacetylation of lysine 19 is important for full enzyme activity. The physiological functions of N-acyl amino acids are not well studied to date. In this thesis, we have identified that N-arachidonoyl taurine and N-oleoyl taurine trigger insulin secretion by increasing the calcium flux in pancreatic b-cells via the activation of transient receptor potential vanilloid subfamily 1 (TRPV1). This work on N-acyl amino acids has led us to identify new pathways and physiological functions for these lipid signalling molecules, which advances our knowledge of the importance of these lipids in mammalian systems.

At the time of doctoral defence the following papers were unpublished and had a status as follows:Paper 2: Accepted; Paper 3: Manuscript; Paper 4; Manuscript

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Krappmann, Sven Kurt. "Biosynthesis of Aromatic Amino Acids in Yeast and Aspergillus." Doctoral thesis, [S.l. : s.n.], 2000. http://hdl.handle.net/11858/00-1735-0000-000D-F20C-1.

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Barnard, Sandra H. "Amalgamation of Nucleosides and Amino Acids in Antibiotic Biosynthesis." UKnowledge, 2013. http://uknowledge.uky.edu/pharmacy_etds/20.

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The rapid increase in antibiotic resistance demands the identification of novel antibiotics with novel targets. One potential antibacterial target is the biosynthesis of peptidoglycan cell wall, which is both ubiquitous and necessary for bacterial survival. Both the caprazamycin-related compounds A-90289 and muraminomicin, as well as the capuramycin-related compounds A-503083 and A-102395 are potent inhibitors of the translocase I enzyme, one of the key enzymes required for cell wall biosynthesis. The caprazamycin-related compounds contain a core nonproteinogen b-hydroxy-a-amino acid referred to as 5’-C-glycyluridine (GlyU). Residing within the biosynthetic gene clusters of the aforementioned compounds is a shared open reading frame which encodes a putative serine hydroxymethyltransferase (SHMT). The revelation of this shared open reading frame resulted in the proposal that this putative SHMT catalyzes an aldol-type condensation reaction utilizing glycine and uridine-5’-aldehyde, resulting in the GlyU core. The enzyme LipK involved in A-90289 biosynthesis was used as a model to functionally assign this putative SHMT to reveal its functions as an l-threonine: uridine-5’-aldehyde transaldolases. Biochemical analysis indicates enzymatic activity is dependent upon pyridoxal-5’-phosphate, is non-reactive with alternative amino acids, and produces acetaldehyde as a co-product. Structural characterization of the enzymatic product is consistent with (5’S,6’S)-GlyU indicating that this enzyme orchestrates a C-C bond breaking and formation resulting in two new stereocenters to make a new l-a-amino acid. The same activity was demonstrated for the LipK homologues involved in the biosynthesis of muraminomicin, A-503083, and A-102395. This l-threonine: uridine-5’-aldehyde transaldolase was used with alternative aldehyde substrates to prepare unusual l-a-amino acids, suggesting the potential for exploiting this enzyme to make new compounds.
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Brown, Judy Forsyth. "Regulation in aromatic amino acid biosynthesis in Saccharomyces cerevisiae." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/12947.

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Murphey, Roberta Jean. "Synthesis of deoxyhypusine in eukaryotic initiation factor 4D in rat hepatoma cells." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184691.

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The aim of this research was to study the mechanism involved in the synthesis of deoxyhypusine, the intermediate step in the synthesis of the amino acid hypusine. Oeoxyhypusine is derived from the butylamine moiety of a spermidine molecule which is added to the famino group of one lysine in the eukaryotic initiation factor 40 (eIF-4D). Initially, a hepatoma tissue cell (HTC) lysate with a pH of 9.5 in glycine buffer and with a depleted spermidine pool supported deoxyhypusine synthesis in protein. Since CHES buffer was as efficient as glycine buffer, the synthesis of deoxyhypusine was pH dependent (optimum ∼9.2) and not buffer dependent. Next, several inhibitors were used in the cell-free system to block deoxyhypusine synthesis. Only guazatine, a plant amine oxidase inhibitor, completely inhibited deoxyhypusine synthesis. This suggested that an oxidase was involved in deoxyhypusine synthesis. In addition factors were investigated as possible allosteric stimulators of deoxyhypusine formation. NAD⁺, NADH, FAD⁺, FMN⁺, and as nicotinamide were tested for effects on deoxyhypusine formation. NAD⁺ was the most efficient stimulator, but NAOH and nicotinamide also stimulated deoxyhypusine formation. Although these factors increased the synthesis of deoxyhypusine, these assays were done in buffer with low concentrations of spermidine. When the spermidine pool was replenished, these effects were diminished. Thus, it appeared that NAD⁺ may lower the apparent K(m) for spermidine without affecting the V(max) of deoxyhypusine synthesis. The inhibition of deoxyhypusine synthesis by guazatine implied the involvement of a polyamine oxidase. Therefore, the effect of oxygen depletion on deoxyhypusine formation was investigated. The depletion of oxygen reduced the level of deoxyhypusine synthesis to 12% of the control. This activity could be restored to 85% by reoxygenation of the lysate. Thus in support of the suggestion made by the guazatine data, a spermidine oxidase in involved in deoxyhypusine formation. The most significant contribution of this work was the development of a cell free system to study deoxyhypusine. This synthesis required an unusually high pH in vitro and required polyamine depletion (Chapter 2). In addition, synthesis requires a unique spermidine oxidase that is blocked by a guazatine and is conditionally stimulated by NAD⁺ (Chapter 3).
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Ng, S. C. "Enzymatic and non enzymatic synthesis of amino acid derivatives." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379948.

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Nili, Nafisseh. "Limitations to amino acid biosynthesis de novo in ruminal strains of Prevotella and Butyrivibrio." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phn712.pdf.

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Bibliography: leaves 226-261. Investigates nitrogen utilization in some species of rumen bacteria with the object of understanding the role of ammonia versus exogenous amino acids in relation to microbial growth.
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Lee, Johnny Chien-Yi Biotechnology &amp Biomolecular Sciences Faculty of Science UNSW. "Transcriptional and metabolic responses of yeast Saccharomyces cerevisiae to the addition of L-serine." Publisher:University of New South Wales. Biotechnology & Biomolecular Sciences, 2008. http://handle.unsw.edu.au/1959.4/41012.

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Sudden changes in nutrient resources are common in the natural environment. Cells are able to adapt and propagate under changing environmental conditions by making adjustments in their cellular processes. These cellular adaptations involve genome-wide transcriptional reprogramming that results in the induction or repression of metabolic pathways. Specific enzymes are then synthesised and activated to maximise the use of the newly available nutrient sources. L-serine is one of the twenty proteinogenic amino acids, and can be synthesised in yeast by the glycolytic and gluconeogenic pathways when growing on fermentable or non-fermentable carbon sources or taken up from the environment when available. L-serine is metabolically linked to glycine and is a predominant donor of one-carbon units in one-carbon metabolism. L-serine is also a source of pyruvate and ammonia and contributes to other cellular processes including the biosynthesis of cysteine and phospholipids. Previous work has shown that yeast cells exhibit transcriptional induction of the one-carbon pathway and the genes involved in the synthesis of purine and methionine after the addition of 10 mM glycine. Here it is shown that addition of 10 mM L-serine did not, however, elicit the same transcriptional response. This is primarily due to differences in the uptake of glycine and L-serine in yeast. High concentrations of extracellular L-serine were required for yeast to show an increase in intracellular L-serine concentration of the magnitude required to trigger a noticeable cellular response. Despite L-serine and glycine being interconvertable via the SHMT isozymes and being a one-carbon donor, the genome-wide transcriptional response exhibited by cells in response to L-serine addition was markedly different to that seen for glycine. The predominant response to an increase in intracellular L-serine was the induction of the general amino acid control system and the CHA1 gene encoding the serine (threonine) dehydratase. Unlike glycine, addition of L-serine triggered only minor induction of the one-carbon pathway. A large portion of intracellular L-serine was converted to pyruvate and ammonia in the mitochondrion as the result of induction of CHA1. The high intracellular concentration of L-serine stimulated the cell to increase the production of oxaloacetate and to increase the biosynthesis of L-aspartate. Transient increases in the intracellular L-glutamate and L-glutamine were also observed after the addition of L-serine. The work presented in this study shows that large increase in the intracellular concentration of amino acid is required to trigger a significant transcriptional response. Yeast cells exhibit different transcriptional and metabolic responses to the addition of L-serine and glycine even though these two amino acids are closely metabolically linked. Addition of L-serine provokes the GAAC response, expression of the CHA1 gene and stimulates the biosynthesis of L-aspartate in yeast whereas addition of glycine induces the one-carbon pathway which leads to the biosynthesis of the purine nucleotides.
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Chan, K. K. Jason. "Identification and enzyme studies of rare amino acid biosynthesis from Streptomyces cattleya." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/4478.

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This thesis is focussed on the biosynthesis of three toxins: fluoroacetate, 4-fluoro-L-theronine and β-ethynyl-L-serine which are biosynthesised by the soil bacteria Streptomyces cattleya. The two fluorinated metabolites originate from a common biosynthetic pathway and the thesis describes studies carried out on an aldose-ketose isomerase enzyme of the pathway. The biosynthetic origin of β-ethynyl-L-serine is not known. A total synthesis of this acetylenic amino acid is descibed along with the development of a new analytical method for identifying the metabolite and for future isotope-labelling based biosynthetic studies. Chapter 1 presents the background of this research. It is focussed on the biosynthesis of fluoroacetate and 4-fluoro-L-threonine by S. cattleya and it also introduces alkyne-containing natural products and their biosynthesis. Chapter 2 describes the work carried out on crystallisation of the aldose-ketose isomerase of the fluorometabolite pathway in S. cattleya. Crystals of the isomerase were obtained and they were diffracted by X-ray, however a structure could not be solved. Chapter 3 contains site-directed mutagenesis studies of the isomerase from S. cattleya. Chapter 4 describes an enantioselective total synthesis of β-ethynyl-L-serine. A robust analytical technique based on derivatisation using 'Click' chemistry and LC-MS was developed for the detection of this amino acid directly from the fermentation broth. Chapter 5 details the experimental procedures for compounds synthesised in this thesis and the biological procedures for gene cloning and protein purification.
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Al-Bar, Omar Abdulrahman Mostafa. "Modified amino acids and peptides as potential inhibitors of bacterial cell wall biosynthesis." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303364.

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Books on the topic "Amino acids – Biosynthesis"

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Workshop on the Biosynthesis of Branched Chain Amino Acids (1988 Beer-sheva, Israel). Biosynthesis of branched chain amino acids. Weinheim: VCH, 1990.

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Arnstein, H. R. V. Protein biosynthesis. [Oxford, England]: IRL Press at Oxford University Press, 1992.

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J, Stetter, and Brown H. M, eds. Herbicides inhibiting branched-chain amino acid biosynthesis: Recent developments. Berlin: Springer-Verlag, 1994.

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Amino acid and peptide synthesis. Oxford: Oxford University Press, 1992.

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1952-, Singh Bijay K., Flores Hector E. 1950-, and Shannon Jack C. 1935-, eds. Biosynthesis and molecular regulation of amino acids in plants. Rockville, Md: American Society of Plant Physiologists, 1992.

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1940-, Barak Z., Chipman D. M, and Schloss J. V, eds. Biosynthesis of branched chain amino acids: Proceedings of the Workshop on the Biosynthesis of Branched Chain Amino Acids, Beer-sheva, Israel, November 1988. [S.l.]: Balaban Publishers, 1990.

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Bodanszky, Miklos. Peptide chemistry: A practical textbook. 2nd ed. Berlin: Springer-Verlag, 1993.

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M, Mazoyer B., Heiss, W.-D. 1939 Dec. 31-, Comar D, and European Economic Community, eds. PET studies of amino acid metabolism and protein synthesis: Proceedings of workshop held in Lyon, France within the framework of the European Community medical and public health research. Dordrecht: Kluwer Academic Publishers, 1993.

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E, Conn Eric, and Phytochemical Society of North America. Meeting, eds. The Shikimic acid pathway. New York: Plenum Press, 1986.

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R, Adams M., ed. Microorganisms in the production of food. Amsterdam: Elsevier, 1986.

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Book chapters on the topic "Amino acids – Biosynthesis"

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Kubicek, C. P., C. Hönlinger, W. M. Jaklitsch, K. Affenzeller, R. Mach, T. U. Gerngross, and Lu Ying. "Regulation of lysine biosynthesis in the fungus Penicillium chrysogenum." In Amino Acids, 1029–34. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-011-2262-7_128.

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Koide, Hiroshi, Mitsuko Oishi, Takanori Oka, Tetsuo Miyake, Toru Fuwa, Shigeyuki Yokoyama, and Tatsuo Miyazawa. "Biosynthesis of epidermal growth factor having nonprotein amino acid residues by Escherichia coli." In Amino Acids, 193–200. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-011-2262-7_23.

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Parker, Emily J., and Andrew J. Pratt. "Amino Acid Biosynthesis." In Amino Acids, Peptides and Proteins in Organic Chemistry, 1–82. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2011. http://dx.doi.org/10.1002/9783527631803.ch1.

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Smith, C. A., and E. J. Wood. "Nitrogen fixation and incorporation of nitrogen into amino acids." In Biosynthesis, 93–113. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2356-3_5.

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Henner, Dennis, and Charles Yanofsky. "Biosynthesis of Aromatic Amino Acids." In Bacillus subtilis and Other Gram-Positive Bacteria, 269–80. Washington, DC, USA: ASM Press, 2014. http://dx.doi.org/10.1128/9781555818388.ch19.

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Spiteller, Peter. "β-Amino Acid Biosynthesis." In Amino Acids, Peptides and Proteins in Organic Chemistry, 119–61. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527631766.ch4.

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Cohen, G. N. "The Aspartic Acid Family of Amino Acids: Biosynthesis." In Microbial Biochemistry, 257–74. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9437-7_25.

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Cohen, G. N. "The Aspartic Acid Family of Amino Acids: Biosynthesis." In Microbial Biochemistry, 289–308. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-8908-0_25.

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Cohen, Georges N. "The Aspartic Acid Family of Amino Acids: Biosynthesis." In Microbial Biochemistry, 393–417. Dordrecht: Springer Netherlands, 2016. http://dx.doi.org/10.1007/978-94-017-7579-3_25.

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Cohen, Georges N. "The aspartic acid family of amino acids. Biosynthesis." In Microbial Biochemistry, 139–49. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-1-4020-2237-1_22.

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Conference papers on the topic "Amino acids – Biosynthesis"

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Ohtsuki, Takashi, Yoshio Doi, Taishi Manabe, and Masahiko Sisido. "Expansion of protein biosynthesis system including nonnatural amino acids." In 2006 IEEE International Symposium on MicroNanoMechanical and Human Science. IEEE, 2006. http://dx.doi.org/10.1109/mhs.2006.320251.

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KATO, S., Y. OBA, M. OJIKA, and S. INOUYE. "BIOSYNTHESIS OF CYPRIDINA LUCIFERIN FROM FREE AMINO ACIDS IN CYPRIDINA (VARGULA) HILGENDORFII." In Proceedings of the 13th International Symposium. WORLD SCIENTIFIC, 2005. http://dx.doi.org/10.1142/9789812702203_0028.

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Gaivoronskaya, Irina, and Valenitna Kolpakova. "MATHEMATICAL MODELS FOR THE SYNTHESIS OF PLANT-BASED COMPOSITIONS WITH IMPROVED AMINO ACID COMPOSITION." In GEOLINKS Conference Proceedings. Saima Consult Ltd, 2021. http://dx.doi.org/10.32008/geolinks2021/b1/v3/12.

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The aim of the work was to optimize the process of obtaining multicomponent protein compositions with high biological value and higher functional properties than the original vegetable protein products. Was realized studies to obtain biocomposites on the base of pea protein-oat protein and pea protein-rice protein. Developed composites were enriched with all limited amino acids. For each of the essential amino acids, the amino acid score was 100% and higher. Protein products used in these compositions are not in major allergen list, which allows to use these compositions in allergen-free products and specialized nutrition. To determine biosynthesis parameters for compositions from pea protein and various protein concentrates with the use of transglutaminase enzyme, was studied effect of concentration and exposition time on the amount of amino nitrogen released during the reaction. Decreasing of amino nitrogen in the medium indicated the occurrence of a protein synthesis reaction with the formation of new covalent bonds. Were determined optimal parameters of reaction: the hydromodule, the exposure time, the concentration of EP of the preparation, were obtained mathematical models. Studies on the functional properties of composites, the physicochemical properties of the proteins that make up their composition, and structural features will make it possible to determine the uses in the manufacture of food products based on their ability to bind fat, water, form foam, gels, and etc.
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Foster, D., B. Schach, M. Rudisky, K. Berkner, A. Kumar, A. Kumar, C. Sprecher, F. Hagen, and E. W. Davie. "The Effect of Changes in the Leader Sequence of Human Protein C on Biosynthetic Processing and Gamma-Carboxylation." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643993.

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Protein C is the precursor to a serine protease in plasma which contains gamma-carboxy glutamic acid and functions as a potent anticoagulant. Protein C shows considerable structural homology with the other vitamin K-dependent coagulation factors including prothrombin, factor VII, factor IX and factor X. Sequence analysis ofthe cDNAs for these proteins has revealedthe presence of a prepro leader sequence that contains a pre sequence or hydrophobic signal sequence and a propeptide containing a number of highly conserved amino acids. The pre region is removed from thegrowing polypeptide chain by signal peptidase, while the pro region is subsequently removed from the protein prior to secretion. Deletion mutants have been constructed in the propeptide portion of the cDNAfor human protein C in order to test the possibility that the propeptide portion of the 42 amino acid leader sequence serves as a molecular signal for gamma-carboxylation.Accordingly, these mutants containthe pre-peptide (hydrophobic leader) plusportions of the pro-peptide at the amino terminus of the light chain. These deletions include the removal of 4, 9, 12, 15, 16 or 17 amino acids from the carboxyl end of the leader sequence of 42 amino acids. The mutant proteins were expressed in carboxylation-competent mammalian cells and were then examined by Western blotting, barium citrate adsorption and precipitation, amino acid sequence analysis, and biological activity and compared with the native protein present in normal plasma. These studies have shown that deletions inthe pro-peptide region interfere with gamma-carboxylation and removal of the pro-peptide. Deletion of residues -1 through -12 had little effect on the carboxylationor secretion. Deletion of -1 through -17 completely abolished gamma-carboxylation, but had no measurable effect on secretion.Amino terminal sequence analysis of thelatter mutant showed that the light chainbegan with Thr-Pro-Ala-Pro... This corresponds to a sequence in the prepro leader starting at -24. This indicates that the signal peptidase cleavage site for human protein C is between residues -25 and -24 and removal of the pro-peptide had been blocked by the deletion.Furthermore, during biosynthesis and secretion, the amino-terminal region of the propeptide (residues from about -12 through -17) are important for carboxylation of protein C, while the carboxyl-terminal portion of the peptide (residues -1 through -4) are important for the removal of the proleader sequence by proteolytic processing.
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Aplakov, V. "The role of wine basic organic and amino acids in proline biosynthesis during secondary alcoholic fermentation." In General question of world science. "Наука России", 2019. http://dx.doi.org/10.18411/gq-30-03-2019-20.

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Leal-Guerra, C. S., E. Pérez-Ortega, L. Damas-Buenrostro, J. C. Cabada, L. Galán-Wong, and B. Pereyra-Alférez. "Biosynthesis of amino acids sulfur in Saccharomyces cerevisiae is affected by fermentation conditions in beer production." In Proceedings of the III International Conference on Environmental, Industrial and Applied Microbiology (BioMicroWorld2009). WORLD SCIENTIFIC, 2010. http://dx.doi.org/10.1142/9789814322119_0125.

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Gilvanova, E. A., and P. Yu Milman. "Auxin and carotene biosynthesis by the bacterium Pantoea agglomerans." In 2nd International Scientific Conference "Plants and Microbes: the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.086.

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Monitoring of auxin and carotene during cultivation of the Pantoea agglomerans strain IB-BF revealed that the maximum yield of the target products is provided not by population density, but by the qualitative composition of the nutrient medium and the need for a larger peptide component of the substrate (rich amino acid set), which is part of the standard LB medium.
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Foster, D., B. Schach, M. Rudinsky, K. Berkner, A. Kumar, C. Sprecher, F. Hagen, and E. W. bavie. "The Effect of Changes in the Leader Sequence of Human Protein C on Biosynthetic Processing and Gamma-Carboxylation." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643648.

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Protein C is the precursor to a serine protease in plasma which contains gamma-carboxy glutamic acid and functions as a potent anticoagulant. Protein C shows considerable structural homology with the other vitamin K-dependent coagulation factors including prothrombin, factor VII, factor IX and factor X. This homology includes the putative pro-peptide region of the prepro leader sequences for these proteins, as well as the leader sequences for gamma-carboxylated proteins from bone. Deletion mutants have been constructed in the cDNA for human protein C in order to test the possibility that the pro-peptide portion of the 42 amino acid leader sequence serves as a molecular signal for gamma-carboxylation. Accordingly, these mutants contain the pre-peptide (hydrophobic leader) plus portions of the pro-peptide at the amino terminus of the light chain. The mutant proteins were expressed in carboxylation-competent mammalian cells and analyzed by barium citrate precipitation and N-terminal amino acid sequencing. These studies have shown that deletions in the pro-peptide region interfere with gamma-carboxylation and removal of the pro-peptide. Deletion of residues −1 through −12 had little effect on the carboxylation or secretion. Deletion of −1 through −17 completely abolished gamma-carboxylation, but had no measurable effect on secretion. Amino terminal sequence analysis of the latter mutant showed that the light chain began with Thr-Pro-Ala-Pro... This corresponds to a sequence in the prepro leader starting at −24. This indicates that the signal peptidase cleavage site for human protein C is between residues −25 and −24 and removal of the pro-peptide had been blocked by the deletion.
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Hao, Da Cheng, and Jun Mu. "Positive Selection of Paclitaxel Biosynthetic Genes Detected at Both Nucleotide and Amino Acid Levels." In 2009 2nd International Conference on Biomedical Engineering and Informatics. IEEE, 2009. http://dx.doi.org/10.1109/bmei.2009.5305785.

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Pittman, Debra D., Louise C. Wasley, Beth L. Murray, Jack H. Wang, and Randal J. Kaufman. "ANALYSIS OF STRUCTURAL REQUIREMENTS FOR FACTOR VIII FUNCTION USING SITE-DIRECTED MUTAGENESIS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644044.

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Factor VIII (fVIII) functions in the intrinsic pathway of coagulation as the cofactor for Factor IXa proteolytic activation of Factor X. fVIII contains multiple sites which are susceptible to cleavage by thrombin, Factor Xa, and activate) protein C. Proteolytic cleavage is required for cofactor activity and may be responsible for inactivation of cofactor activity. In order to identify the role ofthe individual cleavages of fVIII in its activation and inactivation, site-directed DNA mediated mutagenesis of fVIII was performed and the altered forms of fVIII produced and characterized. Conversionof Arg residues to lie residues at amino acid positions 740, 1648, and 1721 resulted in resistance to thrombin cleavage at those siteswith no alteration of in vitro procoagulant activity. Modification of the thrombin cleavage sites at either positions 372 or 1689 resulted in loss of cofactor activity suggesting that these sites are important for activation. Modification of the postulated activated protein C cleavage site at position 336 resulted in fVIII with a higher specific activity than wild type, possibly due to resistance toproteolytic inactivation.DNA mediated mutagenesis was also used to study the role of post-translational biosynthetic modifications of fVIII. Structural characterization of recombinant fVIII suggested the presence of sulfated tyrosine residues within two acidic regions located between amino acid residues 336-372 and 1648-1689. Individual modification of theseTyr residues to Phe had negligible effect on synthesis and in vitrocofactor activity. The effect of combinations of these mutations onsecretion, cofactor activity, and vWF interaction will be presented.
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Reports on the topic "Amino acids – Biosynthesis"

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Jander, Georg, Gad Galili, and Yair Shachar-Hill. Genetic, Genomic and Biochemical Analysis of Arabidopsis Threonine Aldolase and Associated Molecular and Metabolic Networks. United States Department of Agriculture, January 2010. http://dx.doi.org/10.32747/2010.7696546.bard.

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Since the amino acids threonine and isoleucine can be limiting in mammalian diet and there is interest in increasing their abundance in certain crop plants. To meet this need, a BARD proposal was written with two main research objectives: (i) investigate new avenues for manipulating threonine and isoleucine content in plants and (ii) study the role of threonine aldolase in plant metabolism. Research conducted to meet these goals included analysis of the sub-cellular localization of threonine aldolase in the plant, analysis of metabolic flux in developing embryos, over- and under-expression of Arabidopsis threonine aldolases, and transcriptional and metabolic analysis of perturbations resulting from altered threonine aldolase expression. Additionally, the broader metabolic effects of increasing lysine biosynthesis were investigated. An interesting observation that came up in the course of the project is that threonine aldolase activity affects methionine gamma-lyase in Arabidopsis. Further research showed that threonine deaminase and methionine gamma-lyase both contribute to isoleucine biosynthesis in plants. Therefore, isoleucine content can be altered by manipulating the expression of either or both of these enzymes. Additionally, both enzymes contribute to the up to 100-fold increase in isoleucine that is observed in drought-stressed Arabidopsis. Toward the end of the project it was discovered that through different projects, both groups had been able to independently up-regulate phenylalanine accumulation by different mechanisms. The Galili lab transformed Arabidopsis with a feedbackinsensitive bacterial enzyme and the Jander lab found a feedback insensitive mutation in Arabidopsis arogenate dehydratase. Exchange of the respective plant lines has allowed a comparative analysis of the different methods for increasing phenylalanine content and the creation of double mutants. The research that was conducted as part of this BARD project has led to new insights into plant amino acid metabolism. Additionally, new approaches that were found to increase the accumulation of threonine, isoleucine, and phenylalanine in plants have potential practical applications. Increased threonine and isoleucine levels can increase the nutritional value of crop plants. Elevated isoleucine accumulation may increase the osmotic stress tolerance of plants. Up-regulation of phenylalanine biosynthesis can be used to increase the production of downstream higher-value plant metabolites of biofuel feed stocks.
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Sengupta-Gopalan, Champa, Shmuel Galili, and Rachel Amir. Improving Methionine Content in Transgenic Forage Legumes. United States Department of Agriculture, February 2001. http://dx.doi.org/10.32747/2001.7580671.bard.

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Leguminous forage crops are high in proteins but deficient in S- amino acids. It has been shown that both wool quality and milk production can be limited by the post-ruminal supply of sulfur-containing amino acids. Efforts to use conventional plant breeding and cell selection techniques to increase the S-amino acid content of alfalfa have met with little success. With the objective to increase the S-amino acid content of forage legumes, the goal of this project was to co- express the methionine rich zein genes from corn along with a gene for a key enzyme in methionine biosynthesis, aspartate kinase(AK). The zeins are seed storage proteins from corn and are groupec into four distinct classes based on their amino acid sequence homologies. The b-zein (15kd) and the 6zein (10kD and 18kD) have proportionately high levels of methionine (10%, 22% and 28%, respectively). Initial studies from our lab had shown that while the 15kD zein accumulated to high levels in vegetative tissues of transgenic tobacco the l0kD zein did not. However, co-expression of the 10kD zein with the 15kD zein genes in tobacco showed stabilization of the 10kD zein and the co-localization of the 10kD and 15kD zein proteins in unique ER derived protein bodies. AK is the key enzyme for producing carbon skeletons for all amino acids of the aspartate family including methionine. It is, however, regulated by end-product feedback inhibition. The specific objectives of this proposal were: i. to co-express the 15kD zein with the 10/18kD zein genes in alfalfa in order to enhance the level of accumulation of the 10/18kD zein; ii. to increase methionine pools by expressing a feedback insensitive AK gene in transformants co-expressing the 15kD and 10/18kD zein genes. The Israeli partners were successful in expressing the AK gene in alfalfa which resulted in an increase in free and bound threonine but not in methionine (Galili et al., 2000). Since our target was to increase methionine pools, we changed our second objective to replace the AK gene with the gene for cystathionine gamma synthase (CGS) in the co-expression studies. The first methionine specific reaction is catalyzed by CGS. An additional objective was to develop a transformation system for Berseem clover, and to introduce the appropriate gene constructs into it with the goal of improving their methionine content. Genes for the 15kD zein along with the genes for either the 10kD or 18kD zein have been introduced into the same alfalfa plant both by sexual crosses and by re-transformation. Analysis of these zein co-expressors have shown that both the IOkD and 18kD zein levels go up 5 to 10 fold when co-expressed with the 15kD zein (Bagga et al., MS in preparation). Incubation of the leaves of transgenic alfalfa co-expressing the 15kD and 10kD zein genes, in the rumen of cows have shown that the zein proteins are stable in the rumen. To increase the level of zein accumulation in transgenic alfalfa different promoters have been used to drive the zein genes in alfalfa and we have concluded that the CaMV 35S promoter is superior to the other strong leaf -specific promoters. By feeding callus tissue of alfalfa plants co-expressing the 15kD and 10kD zein genes with methionine and its precursors, we have shown that the zein levels could be significantly enhanced by increasing the methionine pools. We have now introduced the CGS gene (from Arabidopsis; kindly provided to us by Dr. Leustek), into the 15kD zein transformants and experiments are in progress to check if the expression of the CGS gene indeed increases the level of zein accumulation in alfalfa. We were not successful in developing a transformation protocol for Berseem clover.
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Dudareva, Natalia, Alexander Vainstein, Eran Pichersky, and David Weiss. Integrating biochemical and genomic approaches to elucidate C6-C2 volatile production: improvement of floral scent and fruit aroma. United States Department of Agriculture, September 2007. http://dx.doi.org/10.32747/2007.7696514.bard.

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The specific objectives of approved proposal include to: 1. Elucidate the C6-C2 biochemical pathways leading to the biosynthesis of phenylacetaldehyde, phenylethyl alcohol and phenylethyl acetate in floral tissues of ornamentally important plants, pefunia and roses. 2. Isolate and characterrze genes responsible for the production of these C6-C2 compounds and those involved in the regulation of the pathway using genomic and transcriptomic tools. 3. Determine whether altering the expression of key genes of this pathway can result in changing the aroma characteristics of flowers. Aldehydes are intermediates in a variety of biochemical pathways including those involved in the metabolism of carbohydrates, vitamins, steroids, amino acids, benzylisoquinoline alkaloids, hormones, and lipids. In plants they are also synthesized in response to environmental stresses such as salinity, cold, and heat shock or as flavors and aromas in fruits and flowers. Phenylacetaldehyde along with 2-phenylethanol and its acetate ester, are important scent compounds in numerous flowers, including petunias and roses. However, little is known about the biosynthesis of these volatile compounds in plants. We have shown that the formation PHA and 2-phenylethanol from Phe does not occur via trans-cinnamic acid and instead competes with the key enzyme of phenypropanoid metabolism Pheammonia-lyase (PAL) for Phe utilization. Using functional genomic approach and comparative gene expression profiling, we have isolated and characterized a novel enzyme from petunia and rose flowers that catalyzes the formation of the Ca-Czcompound phenylacetaldehyde (PHA) from L-phenylalanine (Phe) by the removal of both the carboxyl and amino groups. This enzyme, designated as phenylacetaldehyde synthases (PAAS), is a bifunctional enzyme that catalyzes the unprecedented efficient coupling of phenylalanine decarboxylation to oxidation, generating phenylacetaldehyde, CO2, ammonia, and hydrogen peroxide in stoichiometric amounts. Down-regulation of PAAS expression via RNA interference-based (RNAi) technology in petunia resulted in no PHA emission when compared with controls. These plants also produced no 2-phenylethanol, supporting our conclusion that PHA is a precursor of 2-phenylethanol. To understand the regulation of scent formation in plants we have also generated transgenic petunia and tobacco plants expressing the rose alcohol acetyltransferase (RhAAT) gene under the control of a CaMV-35S promoter. Although the preferred substrate of RhAAT in vitro is geraniol, in transgenic petunia flowers, it used phenylethyl alcohol and benzyl alcohol to produce the corresponding acetate esters, not generated by control flowers. These results strongly point to the dependence of volatile production on substrate availability. Analysis of the diurnal regulation of scent production in rose flowers revealed that although the daily emission of most scent compounds is synchronized, various independently evolved mechanisms control the production, accumulation and release of different volatiles. This research resulted in a fundamental discovery of biochemical pathway, enzymes and genes involved in biosynthesis of C6-C2s compounds, and provided the knowledge for future engineering plants for improved scent quality.
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Riov, Joseph, Michael Pirrung, and Raphael Goren. Synthesis and Properties of Amino-Acid Analogues in Ethylene Biosynthesis. United States Department of Agriculture, October 1985. http://dx.doi.org/10.32747/1985.7562303.bard.

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Author, Not Given. Gene-Enzyme Relationships of Aromatic Amino Acid Biosynthesis in Higher Plants. Office of Scientific and Technical Information (OSTI), August 2002. http://dx.doi.org/10.2172/834384.

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Ginzberg, Idit, Richard E. Veilleux, and James G. Tokuhisa. Identification and Allelic Variation of Genes Involved in the Potato Glycoalkaloid Biosynthetic Pathway. United States Department of Agriculture, August 2012. http://dx.doi.org/10.32747/2012.7593386.bard.

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Steroidal glycoalkaloids (SGAs) are secondary metabolites being part of the plant defense response. The two major SGAs in cultivated potato (Solanum tuberosum) are α-chaconine and α-solanine, which exhibit strong cellular lytic properties and inhibit acetylcholinesterase activity, and are poisonous at high concentrations for humans. As SGAs are not destroyed during cooking and frying commercial cultivars have been bred to contain low levels, and their content in tubers should not exceed 20 mg/100 g fresh weight. However, environmental factors can increase tuber SGA content above the safe level. The focus of the proposed research was to apply genomic approaches to identify candidate genes that control potato SGA content in order to develop tools for potato improvement by marker-assisted selection and/or transgenic approaches. To this end, the objectives of the proposal included identification of genes, metabolic intermediates and allelic variations in the potato SGAbiosynthetic pathway. The SGAs are biosynthesized by the sterol branch of the mevalonic acid/isoprenoid pathway. Transgenic potato plants that overexpress 3-hydroxy-3-methylglutaryl-CoA reductase 1 (HMG1) or squalene synthase 1 (SQS1), key enzymes of the mevalonic acid/isoprenoid pathway, exhibited elevated levels of solanine and chaconine as well as induced expression of genes downstream the pathway. These results suggest of coordinated regulation of isoprenoid (primary) metabolism and SGA secondary metabolism. The transgenic plants were further used to identify new SGA-related candidate genes by cDNA-AFLP approach and a novel glycosyltransferase was isolated. In addition, genes involved in phytosterol biosynthesis may have dual role and synthesize defense-related steroidal metabolites, such as SGAs, via lanosterol pathway. Potato lanosterol synthase sequence (LAS) was isolated and used to prepare transgenic plants with overexpressing and silencing constructs. Plants are currently being analyzed for SGA content. The dynamics of SGA accumulation in the various organs of a potato species with high SGA content gave insights into the general regulation of SGA abundance. Leaf SGA levels in S. chacoense were 10 to 20-fold greater than those of S. tuberosum. The leptines, SGAs with strong antifeedant properties against Colorado potato beetles, were present in all aerial tissues except for early and mid-developmental stages of above ground stolons, and accounted for the high SGA content of S. chacoense. These results indicate the presence of regulatory mechanisms in most tissues except in stolons that limit the levels of α-solanine and α-chaconine and confine leptine accumulation to the aerial tissues. The genomes of cultivated and wild potato contain a 4-member gene family coding for SQS. Three orthologs were cloned as cDNAs from S. chacoense and heterologously expressed in E. coli. Squalene accumulated in all E. coli lines transformed with each of the three gene constructs. Differential transcript abundance in various organs and amino acid sequence differences in the conserved domains of three isoenzymes indicate subfunctionalization of SQS activity and triterpene/sterol metabolism. Because S. chacoense and S. phureja differ so greatly for presence and accumulation of SGAs, we selected four candidate genes from different points along the biosynthetic pathway to determine if chcor phuspecific alleles were associated with SGA expression in a segregating interspecific diploid population. For two of the four genes (HMG2 and SGT2) F2 plants with chcalleles expressed significantly greater total SGAs compared with heterozygotes and those with phualleles. Although there are other determinants of SGA biosynthesis and composition in potato, the ability of allelic states at two genes to affect SGA levels confirms some of the above transgenic work where chcalleles at two other loci altered SGA expression in Desiree. Present results reveal new opportunities to manipulate triterpene/sterol biosynthesis in more targeted ways with the objective of altering SGA content for both human health concerns and natural pesticide content without disrupting the essential metabolism and function of the phytosterol component of the membranes and the growth regulating brassinosteroids.
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Blumwald, Eduardo, and Avi Sadka. Sugar and Acid Homeostasis in Citrus Fruit. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7697109.bard.

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Citrus fruit quality standards have been determined empirically, depending on species and on the particular growing regions. In general, the TSS (total soluble solids) to total acidity (TA) ratio determines whether citrus fruit can be marketed. Soluble sugars account for most of the TSS during harvest while TA is determined almost solely by the citric acid content, which reaches levels of 1-5% by weight in many cultivated varieties. Acid and sugar homeostasis in the fruit is critical for the management of existing cultivars, the development of new cultivars, the improvement of pre- and post-harvest strategies and the control of fruit quality and disorders. The current proposal (a continuation of a previous proposal) aimed at: (1) completing the citrus fruit proteome and metabolome, and establish a citrus fruit functional database, (2) further characterization of the control of fruit acidity by studying the regulation of key steps affecting citrate metabolism, and determine the fate of citrate during acid decline stage, and (3) Studying acid and sugar homeostasis in citrus fruits by characterizing transport mechanisms across membranes. These aims were completed as the following: (1) Our initial efforts were aimed at the characterization and identification of citric acid transporters in citrus juice cells. The identification of citrate transporters at the vacuole of the citrus juice cell indicated that the steady-state citrate cytosolic concentration and the action of the cytosolic aconitase were key elements in establishing the pH homeostat in the cell that regulates the metabolic shift towards carbon usage in the fruit during the later stages of fruit development. We focused on the action of aconitase, the enzyme mediating the metabolic use of citric acid in the cells, and identified processes that control carbon fluxes in developing citrus fruits that control the fruit acid load; (2) The regulation of aconitase, catalyzing a key step in citrate metabolism, was further characterized by using two inhibitors, citramalte and oxalomalte. These compounds significantly increased citrate content and reduced the enzyme’s activity. Metabolite profiling and changes of amino-acid metabolizing enzymes in oxalomalate- treated cells suggested that the increase in citrate, caused by aconitase inhibition, induces amino acid synthesis and the GABA shunt, in accordance with the suggested fate of citrate during the acid decline stage in citrus fruit. (3) We have placed a considerable amount of time on the development of a citrus fruit proteome that will serve to identify all of the proteins in the juice cells and will also serve as an aid to the genomics efforts of the citrus research community (validating the annotation of the fruit genes and the different ESTs). Initially, we identified more than 2,500 specific fruit proteins and were able to assign a function to more than 2,100 proteins (Katz et al., 2007). We have now developed a novel Differential Quantitative LC-MS/MS Proteomics Methodology for the identification and quantitation of key biochemical pathways in fruits (Katz et al., 2010) and applied this methodology to identify determinants of key traits for fruit quality (Katz et al., 2011). We built “biosynthesis maps” that will aid in defining key pathways associated with the development of key fruit quality traits. In addition, we constructed iCitrus (http://wiki.bioinformatics.ucdavis.edu/index.php/ICitrus), a “functional database” that is essentially a web interface to a look-up table that allows users to use functional annotations in the web to identify poorly annotated citrus proteins. This resource will serve as a tool for growers and field extension specialists.
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Rafaeli, Ada, and Russell Jurenka. Molecular Characterization of PBAN G-protein Coupled Receptors in Moth Pest Species: Design of Antagonists. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7593390.bard.

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The proposed research was directed at determining the activation/binding domains and gene regulation of the PBAN-R’s thereby providing information for the design and screening of potential PBAN-R-blockers and to indicate possible ways of preventing the process from proceeding to its completion. Our specific aims included: (1) The identification of the PBAN-R binding domain by a combination of: (a) in silico modeling studies for identifying specific amino-acid side chains that are likely to be involved in binding PBAN with the receptor and; (b) bioassays to verify the modeling studies using mutant receptors, cell lines and pheromone glands (at tissue and organism levels) against selected, designed compounds to confirm if compounds are agonists or antagonists. (2) The elucidation ofthemolecular regulationmechanisms of PBAN-R by:(a) age-dependence of gene expression; (b) the effect of hormones and; (c) PBAN-R characterization in male hair-pencil complexes. Background to the topic Insects have several closely related G protein-coupled receptors (GPCRs) belonging to the pyrokinin/PBAN family, one with the ligand pheromone biosynthesis activating neuropeptide or pyrokinin-2 and another with diapause hormone or pyrokinin-1 as a ligand. We were unable to identify the diapause hormone receptor from Helicoverpa zea despite considerable effort. A third, related receptor is activated by a product of the capa gene, periviscerokinins. The pyrokinin/PBAN family of GPCRs and their ligands has been identified in various insects, such as Drosophila, several moth species, mosquitoes, Triboliumcastaneum, Apis mellifera, Nasoniavitripennis, and Acyrthosiphon pisum. Physiological functions of pyrokinin peptides include muscle contraction, whereas PBAN regulates pheromone production in moths plus other functions indicating the pleiotropic nature of these ligands. Based on the alignment of annotated genomic sequences, the primary and secondary structures of the pyrokinin/PBAN family of receptors have similarity with the corresponding structures of the capa or periviscerokinin receptors of insects and the neuromedin U receptors found in vertebrates. Major conclusions, solutions, achievements Evolutionary trace analysisof receptor extracellular domains exhibited several class-specific amino acid residues, which could indicate putative domains for activation of these receptors by ligand recognition and binding. Through site-directed point mutations, the 3rd extracellular domain of PBAN-R was shown to be critical for ligand selection. We identified three receptors that belong to the PBAN family of GPCRs and a partial sequence for the periviscerokinin receptor from the European corn borer, Ostrinianubilalis. Functional expression studies confirmed that only the C-variant of the PBAN-R is active. We identified a non-peptide agonist that will activate the PBAN-receptor from H. zea. We determined that there is transcriptional control of the PBAN-R in two moth species during the development of the pupa to adult, and we demonstrated that this transcriptional regulation is independent of juvenile hormone biosynthesis. This transcriptional control also occurs in male hair-pencil gland complexes of both moth species indicating a regulatory role for PBAN in males. Ultimate confirmation for PBAN's function in the male tissue was revealed through knockdown of the PBAN-R using RNAi-mediated gene-silencing. Implications, both scientific and agricultural The identification of a non-peptide agonist can be exploited in the future for the design of additional compounds that will activate the receptor and to elucidate the binding properties of this receptor. The increase in expression levels of the PBAN-R transcript was delineated to occur at a critical period of 5 hours post-eclosion and its regulation can now be studied. The mysterious role of PBAN in the males was elucidated by using a combination of physiological, biochemical and molecular genetics techniques.
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9

Lapidot, Moshe, and Vitaly Citovsky. molecular mechanism for the Tomato yellow leaf curl virus resistance at the ty-5 locus. United States Department of Agriculture, January 2016. http://dx.doi.org/10.32747/2016.7604274.bard.

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Tomato yellow leaf curl virus (TYLCV) is a major pathogen of tomato that causes extensive crop loss worldwide, including the US and Israel. Genetic resistance in the host plant is considered highly effective in the defense against viral infection in the field. Thus, the best way to reduce yield losses due to TYLCV is by breeding tomatoes resistant or tolerant to the virus. To date, only six major TYLCV-resistance loci, termed Ty-1 to Ty-6, have been characterized and mapped to the tomato genome. Among tomato TYLCV-resistant lines containing these loci, we have identified a major recessive quantitative trait locus (QTL) that was mapped to chromosome 4 and designated ty-5. Recently, we identified the gene responsible for the TYLCV resistance at the ty-5 locus as the tomato homolog of the gene encoding messenger RNA surveillance factor Pelota (Pelo). A single amino acid change in the protein is responsible for the resistant phenotype. Pelo is known to participate in the ribosome-recycling phase of protein biosynthesis. Our hypothesis was that the resistant allele of Pelo is a “loss-of-function” mutant, and inhibits or slows-down ribosome recycling. This will negatively affect viral (as well as host-plant) protein synthesis, which may result in slower infection progression. Hence we have proposed the following research objectives: Aim 1: The effect of Pelota on translation of TYLCV proteins: The goal of this objective is to test the effect Pelota may or may not have upon translation of TYLCV proteins following infection of a resistant host. Aim 2: Identify and characterize Pelota cellular localization and interaction with TYLCV proteins: The goal of this objective is to characterize the cellular localization of both Pelota alleles, the TYLCV-resistant and the susceptible allele, to see whether this localization changes following TYLCV infection, and to find out which TYLCV protein interacts with Pelota. Our results demonstrate that upon TYLCV-infection the resistant allele of pelota has a negative effect on viral replication and RNA transcription. It is also shown that pelota interacts with the viral C1 protein, which is the only viral protein essential for TYLCV replication. Following subcellular localization of C1 and Pelota it was found that both protein localize to the same subcellular compartments. This research is innovative and potentially transformative because the role of Peloin plant virus resistance is novel, and understanding its mechanism will lay the foundation for designing new antiviral protection strategies that target translation of viral proteins. BARD Report - Project 4953 Page 2
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