Relevant bibliographies by topics / Amino acid- based systems

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Academic literature on the topic 'Amino acid- based systems'

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Published: 6 September 2023

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Journal articles on the topic "Amino acid- based systems"

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Carrera, Gonçalo V. S. M., Noémi Jordão, Miguel M. Santos, Manuel Nunes da Ponte, and Luís C. Branco. "Reversible systems based on CO2, amino-acids and organic superbases." RSC Advances 5, no. 45 (2015): 35564–71. http://dx.doi.org/10.1039/c5ra03474d.

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Chiral amino-acids in the presence of an organic superbase in a CO2 atmosphere were used to prepare carbamate-based ionic liquids and molten salts. Variation of the superbase and amino acid R-group gave tuneable CO2 release temperatures from the products.
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Hu, Weikang, Mei Ying, Shengmin Zhang, and Jianglin Wang. "Poly(amino acid)-Based Carrier for Drug Delivery Systems." Journal of Biomedical Nanotechnology 14, no. 8 (August 1, 2018): 1359–74. http://dx.doi.org/10.1166/jbn.2018.2590.

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Thompson, Marisa, and Carmen Scholz. "Highly Branched Polymers Based on Poly(amino acid)s for Biomedical Application." Nanomaterials 11, no. 5 (April 26, 2021): 1119. http://dx.doi.org/10.3390/nano11051119.

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Polymers consisting of amino acid building blocks continue to receive consideration for biomedical applications. Since poly(amino acid)s are built from natural amino acids, the same building blocks proteins are made of, they are biocompatible, biodegradable and their degradation products are metabolizable. Some amino acids display a unique asymmetrical AB2 structure, which facilitates their ability to form branched structures. This review compares the three forms of highly branched polymeric structures: structurally highly organized dendrimers, dendrigrafts and the less organized, but readily synthesizable hyperbranched polymers. Their syntheses are reviewed and compared, methods of synthesis modulations are considered and variations on their traditional syntheses are shown. The potential use of highly branched polymers in the realm of biomedical applications is discussed, specifically their applications as delivery vehicles for genes and drugs and their use as antiviral compounds. Of the twenty essential amino acids, L-lysine, L-glutamic acid, and L-aspartic acid are asymmetrical AB2 molecules, but the bulk of the research into highly branched poly(amino acid)s has focused on the polycationic poly(L-lysine) with a lesser extent on poly(L-glutamic acid). Hence, the majority of potential applications lies in delivery systems for nucleic acids and this review examines and compares how these three types of highly branched polymers function as non-viral gene delivery vectors. When considering drug delivery systems, the small size of these highly branched polymers is advantageous for the delivery of inhalable drug. Even though highly branched polymers, in particular dendrimers, have been studied for more than 40 years for the delivery of genes and drugs, they have not translated in large scale into the clinic except for promising antiviral applications that have been commercialized.
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Steczko, J., K. C. Bax, and S. R. Ash. "Effect of Hemodiabsorption and Sorbent-Based Pheresis on Amino Acid Levels in Hepatic Failure." International Journal of Artificial Organs 23, no. 6 (June 2000): 375–88. http://dx.doi.org/10.1177/039139880002300606.

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Changes in plasma amino acid concentrations were measured in patients with hepatic failure during extracorporeal hemodiabsorption (using the Liver Dialysis Unit, “the Unit”) or hemodiabsorption plus sorbent-based pheresis treatment (using the Liver Dialysis Plasmafilter Unit, “the PF-Unit”) Systems. Eight patients with hepatic failure, grade 3 or 4 encephalopathy, elevated bilirubin and/or creatinine levels and respiratory or renal failure were treated for 1–3 days with the Unit alone. Three of these were also treated with the Unit containing 10 g of BCAA in the sorbent suspension. Four patients with hepatic failure treated with the PF Unit also had 10 g of branched chain amino acid (BCAA) added to the sorbents of the Unit portion of this device. Pre- and post-plasma samples were drawn and high performance liquid chromatography (HPLC) was used to separate and detect amino acids in the plasma. Both the Unit and the PF-Unit have the capability to selectively remove various amino acids, especially aromatic amino acids (AAA). The pre-treatment amino acid profiles of plasma were typical for hepatic failure, with abnormally high levels of phenylalanine, tyrosine, tryptophan, and methionine and decreased levels of valine, leucine and isolucine. The average pre-treatment Fischer ratio (BCAA/AAA) for both Unit and PF-Unit patients was 1.43 (±0.58). Treatments by both systems resulted in an increase of BCAA levels in blood and concomitant decrease of AAA levels, with an average Fischer ratio improvement of 30–38% for the Unit and PF-Unit without BCAA. The Fischer ratio improved by 90% (average) for the Unit with BCAA. Levels of many other amino acids (such as alanine, glycine, proline or lysine) increased during both Unit and PF-Unit treatments. The removal of strongly protein-bound toxin and amino acids such as tryptophan and sulphydryl amino acids was more effective by the PF-Unit. Both the Unit and the PF-Unit have the unique capability to remove toxic aromatic amino acids while increasing BCAA levels in patient. The increase in many amino acid levels may be related to the removal of toxins that interfere with normal amino acid metabolism. The addition of the PF module improves the removal of bilirubin and similarly protein-bound chemicals. Changes in amino acid profiles by the Unit and the PF-Unit contrast markedly with other extracorporeal devices.
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Bartlett, Stacey, Mariusz Skwarczynski, Xin Xie, Istvan Toth, Alex Loukas, and Ramon M. Eichenberger. "Development of natural and unnatural amino acid delivery systems against hookworm infection." Precision Nanomedicine 3, no. 1 (January 30, 2020): 471–82. http://dx.doi.org/10.33218/prnano3(1).191210.1.

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Peptide-based vaccines consist of short antigen fragments derived from a specific pathogen. Alone, these peptide fragments are poorly or non-immunogenic; however, when incorporated into a proper delivery system, they can trigger strong immune responses. To eliminate the need for toxic and often ineffective oral adjuvants, we designed single molecule-based self-adjuvating vaccines against hookworms using natural and unnatural hydrophobic amino acids. Two vaccine conjugates were synthesized, consisting of B-cell epitope p3, derived from the hookworm Na-APR-1 protein; universal T-helper peptide P25; and either double copies of unnatural lipoamino acid (2-amino-D,L-eicosanoic acid), or ten copies of the natural amino acid leucine. After challenge with the model hookworm, Nippostrongylus brasiliensis, mice orally immunized with the conjugates, but without adjuvant, generated antibody responses against the hookworm epitope, resulting in significantly reduced worm and egg burdens compared to control mice. We have demonstrated that vaccine nanoparticles composed exclusively of natural amino acids can be effective even when administered orally.
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Stücheli, Patrick E., Thomas Larsen, Bernhard Wehrli, and Carsten J. Schubert. "Amino acid and chlorin based degradation indicators in freshwater systems." Geochimica et Cosmochimica Acta 304 (July 2021): 216–33. http://dx.doi.org/10.1016/j.gca.2021.04.006.

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Chican, I. E., D. Vărăşteanu, I. Fierăscu, R. C. Fierăscu, and M. Deaconu. "Surface properties in surfactant systems containing amino acid-based surfactants." IOP Conference Series: Materials Science and Engineering 572 (August 2, 2019): 012009. http://dx.doi.org/10.1088/1757-899x/572/1/012009.

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Abbas, Sam H., and Dirk Schulze-Makuch. "Amino acid synthesis in Europa's subsurface environment." International Journal of Astrobiology 7, no. 3-4 (October 2008): 193–203. http://dx.doi.org/10.1017/s1473550408004114.

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AbstractIt has been suggested that Europa's subsurface environment may provide a haven for prebiotic evolution and the development of exotic biotic systems. The detection of hydrogen peroxide, sulfuric acid, water, hydrates and related species on the surface, coupled with observed mobility of icebergs, suggests the presence of a substantial subsurface liquid reservoir that actively exchanges materials with the surface environment. The atmospheric, surface and subsurface environments are described with their known chemistry. Three synthetic schemes using hydrogen peroxide, sulfuric acid and hydrocyanic acid leading to the production of larger biologically important molecules such as amino acids are described. Metabolic pathways based on properties of the subsurface ocean environment are detailed. Tidal heating, osmotic gradients, chemical cycling, as well as hydrothermal vents, provide energy and materials that may support a course of prebiotic evolution leading to the development or sustenance of simple biotic systems. Putative organisms may employ metabolic pathways based on chemical oxidation–reduction cycles occurring in the putative subsurface ocean environment.
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Mokshina, Nadezhda Ya, Oksana A. Pakhomova, Gennadiy V. Shatalov, and Irina I. Kosinova. "INTERPHASE DISTRIBUTION OF SOME AMINO ACIDS IN EXTRACTION SYSTEMS BASED ON N-VINYLFORMAMIDE COPOLYMERS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 1 (January 10, 2019): 4–10. http://dx.doi.org/10.6060/ivkkt.20196201.5763.

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The extraction characteristics of amino acids and mono-amides of acids were studied using copolymers of N-vinylformamide with 1-vinyl- and 1-methacryloyl-3,5-dimethylpyrazole as extractants. Synthesis of water-soluble copolymers was carried out by radical copolymerization in dioxane with thermoinitiation with dinitro-azobisisomoic acid. The distribution coefficients and the degree of extraction of analytes for a single extraction in the presence of a salting out agent are calculated. To determine the representatives of amino acids, the method of capillary electrophoresis was used. The most effective extraction systems for the extraction of amino acids and monoamides of acids are proposed: the intrinsic viscosity of polymers, the concentration of polymer and analyte solution, the ratio of phase volumes, the ratio of the mole fractions of N-vinylformamide to 1-vinyl and 1-methacryloyl-3,5-dimethylpyrazole. The results of the most effective interfacial distribution of lysine between a water-salt solution and an extractant are presented, which is a copolymer of N-vinylformamide with 1-methacryloyl-3,5-dimethylpyrazole. The concentration of the copolymer and the ratio of the volumes of equilibrium phases at which the maximum degree of lysine extraction is reached are established. A copolymer of N-vinylformamide with 1-vinyl-3,5-dimethylpyrazole is used for simultaneous extraction of cystine, asparagine and glutamine. The established extraction characteristics allowed a successful separate determination of the amino acid cystine and monoamides (asparagine and glutamine) in a joint presence in an aqueous solution. When choosing the conditions for separate electrophoretic determination of amino acids, the optimal composition of the buffer solution, the type and concentration of the micelle was found. The dependence of the structure of the analytes on their interphase distribution was established, and the complexing power of the copolymers of N-vinylformamide with 1-vinyl- and 1-methacryloyl-3,5-dimethylpyrazole was revealed with respect to the representatives of amino acids. The extraction systems used on the basis of N-vinylformamide copolymers are distinguished by ecological and economic expediency, good metrological indices.
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Shrestha, Rekha Goswami, Lok Kumar Shrestha, and Kenji Aramaki. "Wormlike micelles in mixed amino acid-based anionic/nonionic surfactant systems." Journal of Colloid and Interface Science 322, no. 2 (June 2008): 596–604. http://dx.doi.org/10.1016/j.jcis.2008.03.009.

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Dissertations / Theses on the topic "Amino acid- based systems"

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Vu, Trang. "Rheology control mechanisms for amino acid-based surfactant systems." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1626456205661715.

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Flinn, Nicholas Sean. "A lipidic amino acid based system for peptide delivery and enhancing peptide immunogenicity." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244682.

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Varvarenko, S. M., N. V. Puzko, A. S. Voronov, I. A. Dron, I. T. Tarnavchyk, N. G. Nosova, V. Ja Samaryk, and S. A. Voronov. "Colloidal and Chemical Properties of Polyesters Based on Glutamic Acid and Diols of Different Nature." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35074.

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The paper describes synthesis method and colloid-chemical properties of novel α-amino acid based polyesters with controllable hydrophilic-lipophillic balance. Glutamic acid and diols of different nature based polyesters were obtained via low-temperature activated polyesterefication. Such polymers are able to form micellar structures in self-stabilized water dispersion. Solubilization of water insoluble dyes Sudan and toluene in polymer water solution was studied. Due to micelle forming ability and prognosticated biodegradability to non-toxic products, obtained polymers are promising materials for formation of novel dispersed drug delivery systems. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35074
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Smith, Mark T. "Engineering Cell-Free Systems for Vaccine Development, Self-Assembling Nanoparticles and Codon Reassignment Applications." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4449.

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This dissertation reports on the technology of cell-free protein synthesis (CFPS) including 1) stabilized lyophilized cell-free systems and 2) enhanced heterogeneous cell extracts. This work further considers applications of CFPS systems in 1) rapid vaccine development, 2) functional virus-based nanoparticles, 3) site-specific protein immobilization, and 4) expanding the language of biology using unnatural amino acids. CFPS technology is a versatile protein production platform that has many features unavailable in in vivo expression systems. The primary benefit cell-free systems provide is the direct access to the reaction environment, which is no longer hindered by the presence of a cell-wall. The “openness” of the system makes it a compelling candidate for many technologies. One limitation of CFPS is the necessity of freezing for long-term viable storage. We demonstrate that a lyophilized CFPS system is more stable against nonideal storage than traditional CFPS reagents. The Escherichia coli-based CFPS system in this work is limited by the biocatalytic machinery found natively in E. coli. To combat these limitations, exogenous biocatalysts can be expressed during fermentation of cells prepared into extract. We demonstrate that simple adjustments in the fermentation conditions can significantly increase the activity of the heterogeneous extract. Towards virus-based particles and vaccines, we demonstrate that the open nature of CFPS can be utilized for coexpression of virus proteins and self-assembly of virus particles. This technique allows for the rapid production of potential vaccines and novel functional virus-based nanoparticles. Unnatural amino acids expand the effective language of protein biology. Utilizing CFPS as an expression system, we demonstrated that the incorporation of a single specific unnatural amino acid allows for site-specific immobilization, thus stabilizing the protein against elevated temperatures and chemical denaturants. Current unnatural amino acid incorporation technologies are limited to one or few simultaneous incorporations and suffer from low efficiency. This work proposes a system that could potentially allow for upwards of 40 unnatural amino acids to be simultaneously incorporated, effectively tripling the protein code. These projects demonstrate the power and versatility of CFPS technologies while laying the foundation for promising technologies in the field of biotechnology.
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Coates, Ian A. "Functional amino acid-based gelators." Thesis, University of York, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489189.

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Several libraries of gelators have been reported. We have described the use of Boc-protected i amino acids such as tryptophan, cysteine, alanine, phenylalanine, proline and glutamine for the gelation of organic solvents. Side chain fiinctionality imparted individual gelation properties on these compounds. The gelation solvent, minimum gelation concentration (MGC) and thermal stabilities were measured and related back to the previously published lysine-based gelator Lys. The cysteine-based gelator Cys was used to form gels where gold nanoparticles have been aligned along gel nanofibres
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Joel, Smita. "ENGINEERING PROTEINS WITH UNIQUE CHARACTERISTICS FOR DIAGNOSTICS AND BIOSENSORS." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/180.

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Proteins possess a broad range of structural and functional properties and, therefore, can be employed in a variety of biomedical applications. While a good number of protein-based biosensing systems and biosensors for target analytes have been developed, the search for versatile, highly sensitive and selective sensors with long term stability able to provide fast detection of target analytes continues to be a challenge. To that end, we now report the design and development of modified proteins with tailored characteristics and their further utilization in the development of biosensing systems. We take advantage of binding proteins that undergo a change in conformation upon binding to their respective target ligand analytes for the development of highly selective biosensing systems. The first class of binding proteins that was explored for this purpose was antibodies. A non-canonical site in the variable region of a monoclonal antibody was tagged with a fluorescent probe to sense the binding of analyte to its corresponding antigen-binding site. The strategy employed for designing antibodysensing molecules is universal as it can be employed for sensing any biomolecule of interest provided that there is an available antibody against the target ligand analyte. In a second strategy, we utilized designer glucose recognition proteins (GRPs) that were prepared by incorporation of unnatural amino acids in the glucose/galactose binding protein (GBP) of Escherichia coli and its truncated fragments. By taking advantage of the global incorporation method, we were able to fine-tune the binding affinity and thermal stability of the proteins, thus, allowing for the development of a reagentless fluorescence based fiber optic glucose biosensor capable of monitoring glucose in the hypoglycemic, normal, and hyperglycemic range, as well as in the hypothermic and hyperthermic temperature range.
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Menlove, Kit J. "Model Detection Based upon Amino Acid Properties." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2253.

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Similarity searches are an essential component to most bioinformatic applications. They form the bases of structural motif identification, gene identification, and insights into functional associations. With the rapid increase in the available genetic data through a wide variety of databases, similarity searches are an essential tool for accessing these data in an informative and productive way. In our chapter, we provide an overview of similarity searching approaches, related databases, and parameter options to achieve the best results for a variety of applications. We then provide a worked example and some notes for consideration. Homology detection is one of the most basic and fundamental problems at the heart of bioinformatics. It is central to problems currently under intense investigation in protein structure prediction, phylogenetic analyses, and computational drug development. Currently discriminative methods for homology detection, which are not readily interpretable, are substantially more powerful than their more interpretable counterparts, particularly when sequence identity is very low. Here I present a computational graph-based framework for homology inference using physiochemical amino acid properties which aims to both reduce the gap in accuracy between discriminative and generative methods and provide a framework for easily identifying the physiochemical basis for the structural similarity between proteins. The accuracy of my method slightly improves on the accuracy of PSI-BLAST, the most popular generative approach, and underscores the potential of this methodology given a more robust statistical foundation.
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Gardiner, James. "Conformationally restricted amino acid analogues based on lactams." Thesis, University of Canterbury. Chemistry, 1998. http://hdl.handle.net/10092/8773.

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This thesis describes the synthesis of enamino esters 3(S)-(E)-benzoylamino-3-benzyl- 5-ethoxycarbonylmethylidene-1-methylpyrrolidin-2-one 77, and 3(S)-(E)-benzoylamino-3-benzy 1-5-ethoxycarbonylmethylidene-1-2, 4-dimethoxybenzy lamino-pyrrolidin-2-one 79. These were designed as a new class of conformationally restricted amino acid analogue. Chapter one gives a general introduction to the importance of peptides in nature and the pivotal role peptides play in drug discovery and design. A number of examples are examined to provide an insight into key elements required in peptidomimetic design. Chapter two introduces the process of peptidomimetic design, in particular that of cisamide bond mimics. The synthesis of a new class of conformationally restricted peptidomimetic based on lactams is examined. Chapter 3 discusses the synthesis of succinic acid-derived, and aspartic acid-derived, β-keto esters and amides 23, 24, 28, via a Meldrum's acid procedure. This method provides the basis for the preparation of cyclic enamino esters. The preparation of the β-keto amide methyl-5-(N-ethoxycarbonylmethylcarbamoyl)-4-oxo-pentanoate 24 allowed chain extension in the C-direction in one easy step. Chapter 4 examines the importance of ene-lactams in nature and the synthesis of enamino esters 55, 56, 59, 61, and enamino amides 63 and 64,.via the reaction of a β-keto ester, or amide, with an amine. Compounds 59 and 61 represent examples of 3- substituted cis-amide bond mimics that allow chain extension in both the N and C directions and subsequent incorporation into a peptide sequence. Chapter 5 describes the synthesis of the target phenylalanine-derived 3,3-disubstituted enamino esters 77 and 79, using the methodology established in chapter 4. Reaction of the enolate derived from (2R, 4S)-2-phenyl-3-benzoyl-4-benzyl-1,3-oxazolidin-5-one 65, with tert-butylbromoacetate gave (2R, 4S)-2-phenyl-3-benzoyl-4-benzyl-4-(tertbutyloxycarbonylmethyl)-1,3-oxazolidin-5-one 67. An x-ray crystal structure of 67 revealed that the reaction had proceeded with an inversion of configuration at C4, with the oxazolidinone ring being essentially planar in the solid state. This also revealed that the stereochemistry at C3 could be determined by the stereochemistry of the amino acid from which it was derived. The tert-butyl ester was hydrolyzed and the resulting acid was converted to the β-keto ester 71 upon reaction with meldrum's acid and EtOH. The β-keto ester (2R, 4S)-2-pheny 1-3 -benzoy 1-4-benzy 1-4-(3 -ethoxycarbony 1-2-oxopropyl)-1 ,3-oxazolidin-5-one 71, was reacted with either methylamine, or 2,4- dimethoxybenzylamine (DMBNH₂), and heated at 150°C, under reduced pressure, to give the target 3,3-disubstituted enamino esters 77 and 79. The target enamino ester 77 and 79 allow chain extension in both the N and C-directions and are designed to be incorporated into a peptide sequence to mimic a cis-amide bond and allow investigation into the bio-active conformation of a specific peptide.
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Moss, William Osburn. "Novel amino acid synthons based on ketene thioacetals." Thesis, University of Bath, 1990. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253997.

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Yang, Dengliang. "Investigations of amino acid-based surfactants at liquid interfaces." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/2689.

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Herein are presented collective studies of amino acid-based surfactants, also known as lipoamino acids, at liquid interfaces. Chapter III describes an investigation of domain morphology of N-Stearoylglutamic acid (N-SGA) Langmuir monolayers at the air/water interface by epifluorescence microscopy. Anisotropic feather-like domains were observed in L-enantiomeric monolayers while symmetric circular domains were found in racemic N-SGA monolayers. At a surface pressure of 30 mN/m the enantiomeric domains melted at 31 ??C while the racemic domains melted at 27 ??C. This result is exactly opposite to the behavior found in bulk crystals where the racemate melts at a higher temperature. These results were explained in terms of different molecular packing and hydrogen bonding between bulk crystals and two-dimensional thin films for enantiomeric and racemic compounds. Chapter IV summarizes the investigations of hydrogen bonding in N-acyl amino acid monolayers by vibrational sum-frequency spectroscopy (VSFS). The intermolecular hydrogen bonding interaction between the adjacent molecules through amide-amide groups in N-stearoylalanine (N-SA) is characterized by an NH stretch peak at 3311 cm-1. This is the first time that the amide NH stretching signals have been detected with the VSFS technique. A similar peak was detected at 3341 cm-1on N-SGA monolayer. The higher frequency indicates that the H-bond strength is weaker due to the larger size of the glutamic acid residue. The NH stretch mode can thus be used as a fingerprint of hydrogen bonding among amide-amide groups. A peak at 3050 cm-1 due to hydrogen bonding among carboxyl groups was also resolved from the VSFS spectra. Molecular models of intermolecular hydrogen bonding were proposed.
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Books on the topic "Amino acid- based systems"

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M, Lesk Arthur, and CODATA. Task Group on Coordination of Protein Sequence Data Banks., eds. Computational molecular biology: Sources and methods for sequence analysis. Oxford: Oxford University Press, 1988.

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L, Wang Jason T., Shapiro Bruce A, and Shasha Dennis Elliott, eds. Pattern discovery in biomolecular data: Tools, techniques, and applications. New York: Oxford University, 1999.

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B, Calne Donald, ed. Therapeutic manipulation of excitatory amino acid systems. New York: Advanstar Communications, 1994.

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H, Schlesinger David, ed. Macromolecular sequencing and synthesis: Selected methods and applications. New York: A.R. Liss, 1988.

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Entrez user's guide: Release 24.0. Bethesda, Md: National Library of Medicine, 1996.

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Harren, Jhoti, and Leach Andrew R, eds. Structure-based drug discovery. Dordrecht: Springer, 2007.

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1947-, Sillince Maria, ed. Molecular databases for protein sequences and structure studies: An introduction. Berlin: Springer-Verlag, 1991.

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Abelson, John N., Melvin I. Simon, and Russell F. Doolittle. Molecular Evolution: Computer Analysis of Protein and Nucleic Acid Sequences. Elsevier Science & Technology Books, 1990.

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(Editor), John N. Abelson, Melvin I. Simon (Editor), and Russell F. Doolittle (Editor), eds. Molecular Evolution: Computer Analysis of Protein and Nucleic Acid Sequences, Volume 183: Volume 183: Molecular Evolution (Methods in Enzymology). Academic Press, 1990.

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(Editor), John N. Abelson, Melvin I. Simon (Editor), and Russell F. Doolittle (Editor), eds. Molecular Evolution: Computer Analysis of Protein and Nucleic Acid Sequences, Volume 183: Volume 183: Molecular Evolution (Methods in Enzymology). Academic Press, 1990.

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Book chapters on the topic "Amino acid- based systems"

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Danton, M., N. Flinn, W. A. Gibbons, and I. Toth. "Lipidic amino acid based synthetic drug delivery system." In Peptides 1994, 751–52. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-1468-4_346.

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Buntru, Matthias, Simon Vogel, Ricarda Finnern, and Stefan Schillberg. "Plant-Based Cell-Free Transcription and Translation of Recombinant Proteins." In Recombinant Proteins in Plants, 113–24. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2241-4_8.

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AbstractPlant cell-free lysates contain all the cellular components of the protein biosynthesis machinery, providing an alternative to intact plant cells, tissues, and whole plants for the production of recombinant proteins. Cell-free lysates achieve rapid protein production (within hours or days) and allow the synthesis of proteins that are cytotoxic or unstable in living cells. The open nature of cell-free lysates and their homogeneous and reproducible performance is ideal for protein production, especially for screening applications, allowing the direct addition of nucleic acid templates encoding proteins of interest, as well as other components such as enzyme substrates, chaperones, artificial amino acids, or labeling molecules. Here we describe procedures for the production of recombinant proteins in the ALiCE (Almost Living Cell-free Expression) system, a lysate derived from tobacco cell suspension cultures that can be used to manufacture protein products for molecular and biochemical analysis as well as applications in the pharmaceutical industry.
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Tafazoli, Shayesteh, and Fatemeh Rafiemanzelat. "Synthesis and Characterization of Biodegradable and Nontoxic Water Borne Copoly(Ether-Urethane-Urea)s Based on Amino Acid Derivatives." In Eco-friendly and Smart Polymer Systems, 87–91. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45085-4_22.

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Flinn, N., M. Danton, W. A. Gibbons, and I. Toth. "A lipidic α-amino acid based adjuvant-carrier system for drug delivery and enhancing peptide immunogenicity." In Peptides 1994, 839–40. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-1468-4_386.

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Smith, C. A., and E. J. Wood. "Amino acid catabolism." In Energy in Biological Systems, 139–61. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3124-7_7.

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Shi, Zhengshuang, Chunhui Zhou, Zhigang Liu, Filbert Totsingan, and Neville R. Kallenbach. "Amino Acid-Based Dendrimers." In Amino Acids, Peptides and Proteins in Organic Chemistry, 491–517. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2011. http://dx.doi.org/10.1002/9783527631827.ch15.

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Koch, Nikolaj G., and Nediljko Budisa. "Focused Engineering of Pyrrolysyl-tRNA Synthetase-Based Orthogonal Translation Systems for the Incorporation of Various Noncanonical Amino Acids." In Methods in Molecular Biology, 3–19. New York, NY: Springer US, 2023. http://dx.doi.org/10.1007/978-1-0716-3251-2_1.

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Steventon, G. B. "The Amino Acid Conjugations." In Enzyme Systems that Metabolise Drugs and Other Xenobiotics, 501–20. Chichester, UK: John Wiley & Sons, Ltd, 2002. http://dx.doi.org/10.1002/0470846305.ch14.

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Landick, Robert, Dale L. Oxender, and Giovanna Ferro-Luzzi Ames. "Bacterial Amino Acid Transport Systems." In The Enzymes of Biological Membranes, 577–615. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4684-4601-2_17.

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Lu, Guangyuan, Chao-Hsiang Tong, Bruce I. Peterson, and Chi-Tang Ho. "Effect of Water Content and Amino Acids on Maillard Browning Kinetics in Propylene Glycol Based Model Systems During Microwave Heating." In Flavor Technology, 40–48. Washington, DC: American Chemical Society, 1997. http://dx.doi.org/10.1021/bk-1995-0610.ch004.

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Conference papers on the topic "Amino acid- based systems"

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HUANG, JIAN, SHUICHI KAWASHIMA, and MINORU KANEHISA. "NEW AMINO ACID INDICES BASED ON RESIDUE NETWORK TOPOLOGY." In Proceedings of the 7th Annual International Workshop on Bioinformatics and Systems Biology (IBSB 2007). IMPERIAL COLLEGE PRESS, 2007. http://dx.doi.org/10.1142/9781860949920_0015.

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Wulfman, David R., Tracey Baas, and Ronald McGlennen. "Planar Waveguide: Utility in Amino Acid Detection." In ASME 2003 International Electronic Packaging Technical Conference and Exhibition. ASMEDC, 2003. http://dx.doi.org/10.1115/ipack2003-35300.

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A device for the detection of fluorescently labeled nucleic acid sequences immobilized or hybridized to the surface of a planar waveguide has been developed. The device described requires no image gathering or analysis utilities, nor any specially patterned waveguide surface for detection. The system consists of an excitation light source and a photo detector, filters for select fluorescent emissions and a standard glass microscope slide that functions as a planar waveguide (PWG) and assay substrate. The device can discriminate fluorescent DNA products hybridized to a glass based array as effectively as laser based reader instruments, and is a low cost system with a high potential for full automation. The system’s functional parameters are presented along with design schematics of current prototypes. Performance data is also presented showing test results comparable to pre-established fluorescence detection means. Future design goals are also discussed. It is concluded that as a component in telemedicine or other remote medical care strategies, the detection means presented can play a significant role in bringing molecular diagnosis and gene detection to arenas of medical care where it is currently unavailable.
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Gao, Bingtao, Lei Wang, Zhengang Zhai, Yuan Chen, and Jiangang Wang. "Species homology analysis method based on amino acid location and physicochemical properties." In ICAIIS 2021: 2021 2nd International Conference on Artificial Intelligence and Information Systems. New York, NY, USA: ACM, 2021. http://dx.doi.org/10.1145/3469213.3471352.

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Teng, Shaolei, Anand K. Srivastava, and Liangjiang Wang. "Biological Features for Sequence-Based Prediction of Protein Stability Changes upon Amino Acid Substitutions." In 2009 International Joint Conference on Bioinformatics, Systems Biology and Intelligent Computing. IEEE, 2009. http://dx.doi.org/10.1109/ijcbs.2009.101.

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Ma, Xin, Jian-Sheng Wu, Hong-De Liu, Xi-Nan Yang, Jian-Ming Xie, and Xiao Sun. "SVM-Based Approach for Predicting DNA-Binding Residues in Proteins from Amino Acid Sequences." In 2009 International Joint Conference on Bioinformatics, Systems Biology and Intelligent Computing. IEEE, 2009. http://dx.doi.org/10.1109/ijcbs.2009.33.

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Shi, Zhuo-xing, Qi Dai, Ping-an He, Yu-hua Yao, and Bo Liao. "Subcellular localization prediction of apoptosis proteins based on the data mining for amino acid index database." In 2013 7th International Conference on Systems Biology (ISB). IEEE, 2013. http://dx.doi.org/10.1109/isb.2013.6623792.

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Srivastava, Shweta, Gautam Kumar, Tapobarata Lahiri, Rajnish Kumar, Manoj Kumar Pal, Pragya Gupta, and Rahul Gupta. "Prediction of catalytic site of proteins based on amino acid triads approach using non parametric function." In 2016 International Conference on Bioinformatics and Systems Biology (BSB). IEEE, 2016. http://dx.doi.org/10.1109/bsb.2016.7552137.

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Tavares, José, Pedro Brandão, Ivo Barros, Jose Gonçalves, Isabel Praça, Lucia Lacerda, and Marisa Santos. "Machine learning for rectal cancer prediction based on metabolic changes on amino acids." In 2023 IEEE 36th International Symposium on Computer-Based Medical Systems (CBMS). IEEE, 2023. http://dx.doi.org/10.1109/cbms58004.2023.00219.

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Mahfouz, Mohamed A., and Mohamed A. Ismail. "Efficient soft relational clustering based on randomized search applied to selection of bio-basis for amino acid sequence analysis." In 2012 Seventh International Conference on Computer Engineering & Systems (ICCES). IEEE, 2012. http://dx.doi.org/10.1109/icces.2012.6408530.

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Forghani, Majid, Michael Khachay, Artyom Firstkov, and Edward Ramsay. "An Artificial Neural Network Based Ensemble Model for Predicting Antigenic Variants: Application of Reduced Amino Acid Alphabets and Word2Vec." In 2022 8th Iranian Conference on Signal Processing and Intelligent Systems (ICSPIS). IEEE, 2022. http://dx.doi.org/10.1109/icspis56952.2022.10044061.

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Reports on the topic "Amino acid- based systems"

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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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Barash, Itamar, and Robert E. Rhoads. Translational Mechanisms that Govern Milk Protein Levels and Composition. United States Department of Agriculture, November 2004. http://dx.doi.org/10.32747/2004.7586474.bard.

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Original objectives: The long term objective of the project is to achieve higher content of protein in the milk of ruminants by modulating the translational machinery in the mammary gland. The first specific aim of the BARD proposal was to characterize responsiveness of various experimental systems to combination of lactogenic hormones and amino acids with particular emphasis on discrimination between the control of total protein synthesis and milk protein synthesis. Based on the results, we planned to proceed by characterizing the stage of protein synthesis in which the stimulation by lactogenic hormones and amino acid occur and finally we proposed to identify which components of the translation machinery are modified. Background to the topic: Milk protein is the most valuable component in milk, both for direct human consumption and for manufacturing cheese and other protein-based products. Attempts to augment protein content by the traditional methods of genetic selection and improved nutritional regimes have failed. The proposal was based on recent results suggesting that the limiting factor for augmenting protein synthesis in the bovine mammary gland is the efficiency of converting amino acids to milk proteins. Major conclusions, solutions, achievements: Insulin and prolactin synergistically stimulate â-casein mRNA translation by cytoplasmatic polyadenylation. The interaction between insulin and prolactin was demonstrated two decades ago as crucial for milk-protein synthesis, but the molecular mechanisms involved were not elucidated. We found in differentiated CID 9 mouse mammary epithelial cells line that insulin and prolactin synergistically increases the rate of milk protein mRNA translation. We focused on â-casein, the major milk protein, and found that the increase in â-casein mRNA translation was reflected in a shift to larger polysomes, indicating an effect on translational initiation. Inhibitors of the PI3K, mTOR, and MAPK pathways blocked insulin-stimulated total protein and â-casein synthesis but not the synergistic stimulation. Conversely, cordycepin, a polyadenylation inhibitor, abolished synergistic stimulation of protein synthesis without affecting insulin-stimulated translation. The poly(A) tract of â-casein mRNA progressively increased over 30 min of treatment with insulin plus prolactin. The 3’-untranslated region of â-casein mRNA was found to contain a cytoplasmic polyadenylation element (CPE), and in reporter constructs, this was sufficient for the translational enhancement and mRNA-specific polyadenylation. Furthermore, insulin and prolactin stimulated phosphorylation of cytoplasmic polyadenylation element binding protein (CPEB) but did not increase cytoplasmic polyadenylation.
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Forster, Amanda L., Guillaume H. R. Messin, Kirk D. Rice, Michael A. Riley, and Stephanie S. Watson. Study of acid generation from copolymer fibers based on 5-amino-2-(p-aminophenyl)-benzimidazole. Gaithersburg, MD: National Institute of Standards and Technology, 2009. http://dx.doi.org/10.6028/nist.ir.7592.

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Phillips, Donald A., Yitzhak Spiegel, and Howard Ferris. Optimizing nematode management by defining natural chemical bases of behavior. United States Department of Agriculture, November 2006. http://dx.doi.org/10.32747/2006.7587234.bard.

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This project was based on the hypothesis that nematodes interacting with plants as either parasites or beneficial saprophytes are attracted to their host by natural products. This concept was supported by numerous observations that parasitic nematodes are attracted to root exudates. Our overall goal was to identify nematode sensory compounds from root exudates and to use that information for reducing nematicide applications. We applied skills of the investigators to achieve three specific objectives: 1) Identify nematode behavioral cues (e.g., attractants or repellents) in root exudates; 2) Identify new natural nematicidal compounds; and 3) Combine a natural attractant and a nematicide into a nematode trap. Because saprophytic nematodes benefit plants by mineralizing organic matter, we sought compounds attractive primarily to parasitic nematodes. The project was constructed on several complementary foundations. First, data from Dr. Spiegel’s lab showed that under aseptic conditions Ditylenchus dipsaci, a parasite on onion, is attracted to certain fractions of onion root exudates. Second, PI Phillips had a sizeable collection of natural plant products he had identified from previous work on Rhizobium-legume interactions, which could be tested “off the shelf”. Third, Dr. Ferris had access to aseptic and natural populations of various saprophytic and parasitic nematodes. The project focused on five nematode species: D.dipsaci, Heterodera avenae, and Tylenchulussemipenetransat ARO, and Meloidogyne javanicand Caenorhabditis elegans at UCD. Ten pure plant compounds, mostly flavonoids, were tested on the various nematode species using six different assay systems. Results obtained with assorted test systems and by various scientists in the same test systems were essentially irreproducible. Many convincing, Many convincing, i.e. statistically significant, results in one system or with one investigator could not be repeated with other assays or different people. A recent report from others found that these compounds, plus another 30, were inactive as attractants in three additional parasitic nematode species (Wuyts et al. Nematology 8:89- 101, 2006). Assays designed to test the hypothesis that several compounds together are required to attract nematodes have thus far failed to find a reproducibly active combination. In contrast to results using pure plant compounds, complex unfractionated exudates from aseptic onion root reproducibly attracted D. dipsaci in both the ARO and UCD labs. Onion root exudate collection, separation into HPLC fractions, assays using D. dipsaci and MS-MS experiments proceeded collaboratively between ARO and UCD without any definitive identification of an active compound. The final active fraction contained two major molecules and traces of several other compounds. In the end, analytical studies were limited by the amount of onion root exudate and the complexity of the purification process. These tests showed that aseptic plant roots release attractant molecules, but whether nematodes influence that release, as insects trigger release of attractants from plants, is unknown. Related experiments showed that the saprophyte C. elegans stimulates its prey, Pseudomonas bacteria, to increase production of 2, 4-diacetylphloroglucinol (DAPG) a compound that promotes amino acid exudation by plant roots. It is thus possible that saprophytic nematodes are attracted primarily to their bacterial or fungal prey and secondarily to effects of those microorganisms on root exudation. These observations offer promising avenues for understanding root-zone interactions, but no direct routes to controlling nematodes in agriculture were evident. Extracts from two plant sources, Chrysanthemum coronarium and Sequoia sempervirens, showed nematicidal activity at ARO and UCD, respectively. Attempts to purify an active compound from S. sempervirens failed, but preliminary results from C. coronarium are judged to form a potential basis for further work at ARO. These results highlight the problems of studying complex movement patterns in sentient organisms like nematodes and the issues associated with natural product isolation from complex mixtures. Those two difficulties combined with complications now associated with obtaining US visas, slowed and ultimately limited progress on this project. As a result, US investigators expended only 65% of the $207,400 originally planned for this project. The Israeli side of the project advanced more directly toward its scientific goals and lists its expenditures in the customary financial report.
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Amir, Rachel, David J. Oliver, Gad Galili, and Jacline V. Shanks. The Role of Cysteine Partitioning into Glutathione and Methionine Synthesis During Normal and Stress Conditions. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7699850.bard.

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The objective of this research is to study the nature of the competition for cysteine (Cys), the first organic sulfur-containing compound, between its two main metabolites, glutathione (GSH) and methionine (Met). GSH plays a central role in protecting plants during various stresses, while Met, an essential amino acid, regulates essential processes and metabolites in plant cells through its metabolite S-adenosyl-Met. Our results, which are based on flux analysis and measurements of Met- metabolites, show that the flux towards Met synthesis is high during non-stress conditions, however the flux is significantly reduced under stress conditions, when there is high synthesis of GSH. Under oxidative stress the expression level of the regulatory enzyme of Met synthesis, cystathionine g-synthase (CGS) was reduced. By using three different systems, we have found that that GSH down regulates the expression level of CGS, thus reducing Met synthesis. We have found that this regulation occurs at the post-transcriptional level, and further studies have shown that it occurs at post-translationaly. To reveal how oxidative stress affects the flux towards Met and GSH, flux analysis was performed. We have found that the level of Met is significantly reduced, while the level of glutathione significantly increases during stress. Under stress conditions most of the glutathione is converted from GSH to GSSG (the oxidised form of glutathione). These results suggest that under normal growth conditions, Cys is channelled towards both pathways to support GSH accumulation and the synthesis of growth-essential Met metabolites. However, during oxidative stress, when a high level of GSH is required to protect the plants, the levels of GSH increase while those of CGS are reduced. This reduction leaves more Cys available for GSH synthesis under stress conditions. In addition we have also studied the effects of high GSH level on the transcriptome profile. The analysis revealed that GSH affects the expression level of many major genes coding to enzymes or proteins associated with photosynthesis, starch degradation, hormone metabolism (especially genes associated with jasmonate), biotic stress (especially genes associated with PR-proteins), cytochrome P450 genes, regulation of transcription and signaling (especially genes associated with receptor kinases and calcium). These results suggest that indeed GSH levels affect different pathways and metabolites in plants.
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Zhirov, Nikita, Akim Akimov, and Sergei Zhuravkov. Synthesis and properties of bicomponent complex systems based on organic acid and polyoxometalate compound. Peeref, July 2023. http://dx.doi.org/10.54985/peeref.2307p9790614.

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Shpigel, Muki, Allen Place, William Koven, Oded (Odi) Zmora, Sheenan Harpaz, and Mordechai Harel. Development of Sodium Alginate Encapsulation of Diatom Concentrates as a Nutrient Delivery System to Enhance Growth and Survival of Post-Larvae Abalone. United States Department of Agriculture, September 2001. http://dx.doi.org/10.32747/2001.7586480.bard.

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The major bottlenecks in rearing the highly priced gastropod abalone (Haliotis spp.) are the slow growth rate and the high mortality during the first 8 to 12 weeks following metamorphosis and settling. The most likely reason flor these problems is related to nutritional deficiencies in the diatom diet on which the post larvae (PL) feed almost exclusively in captivity. Higher survival and improved growth rate will reduce the considerable expense of hatchery-nursery resisdence time and thereflore the production costs. BARD supported our research for one year only and the support was given to us in order to prove that "(1) Abalone PL feed on encapsulated diatoms, and (2) heterotrophic diatoms can be mass produced." In the course of this year we have developed a novel nutrient delivery system specifically designed to enhance growth and survival of post-larval abalone. This approach is based on the sodium-alginate encapsulation of heterotrophically grown diatoms or diatom extracts, including appetite-stimulating factors. Diatom species that attract the PL and promote the highest growth and survival have been identified. These were also tested by incorporating them (either intact cells or as cell extracts) into a sodium-alginate matrix while comparing the growth to that achieved when using diatoms (singel sp. or as a mixture). A number of potential chemoattractants to act as appetite-stimulating factors for abalone PL have been tested. Preliminary results show that the incorporation of the amino acid methionine at a level of 10-3M to the sodim alginate matrix leads to a marked enhancement of growth. The results ol these studies provided basic knowledge on the growth of abalone and showed that it is possible to obtain, on a regular basis, survival rates exceeding 10% for this stage. Prior to this study the survival rates ranged between 2-4%, less than half of the values achieved today. Several diatom species originated from the National Center for Mariculture (Nitzchia laevis, Navicula lenzi, Amphora T3, and Navicula tennerima) and Cylindrotheca fusiformis (2083, 2084, 2085, 2086 and 2087 UTEX strains, Austin TX) were tested for heterotrophic growth. Axenic colonies were initially obtained and following intensive selection cycles and mutagenesis treatments, Amphora T3, Navicula tennerima and Cylindrotheca fusiformis (2083 UTEX strain) were capable of growing under heterotrophic conditions and to sustain highly enriched mediums. A highly efficient selection procedure as well as cost effective matrix of media components were developed and optimized. Glucose was identified as the best carbon source for all diatom strains. Doubling times ranging from 20-40 h were observed, and stable heterotroph cultures at a densities range of 103-104 were achieved. Although current growth rates are not yet sufficient for full economical fermentation, we estimate that further selections and mutagenesis treatments cycles should result in much faster growing colonies suitable for a fermentor scale-up. As rightfully pointed out by one of the reviewers, "There would be no point in assessing the optimum levels of dietary inclusions into micro-capsules, if the post-larvae cannot be induced to consume those capsules in the first place." We believe that the results of the first year of research provide a foundationfor the continuation of this research following the objectives put forth in the original proposal. Future work should concentrate on the optimization of incorporation of intact cells and cell extracts of the developed heterotrophic strains in the alginate matrix, as well as improving this delivery system by including liposomes and chemoattractants to ensure food consumption and enhanced growth.
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Wong, Eric A., and Zehava Uni. Nutrition of the Developing Chick Embryo: Nutrient Uptake Systems of the Yolk Sac Membrane and Embryonic Intestine. United States Department of Agriculture, June 2012. http://dx.doi.org/10.32747/2012.7697119.bard.

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We have examined the developmental changes in composition, amount, and uptake of yolk nutrients (fat, protein, water and carbohydrates) and the expression ofnutrient transporters in the yolk sac membrane (YSM) from embryonic day 11 (Ell) to 21 (E21) and small intestine from embryonic day 15 (E15) to E21 in embryos from young (22-25 wk) and old (45-50 wk) Cobb and Leghorn breeder flocks. The developmental expression profiles for the peptide transporter 1 (PepTl), the amino acid transporters, EAAT3, CAT-1 and BOAT, the sodium glucose transporter (SGLTl), the fructose transporter (GLUT5), the digestive enzymes aminopeptidase N (APN) and sucraseisomaltase (SI) were assayed by the absolute quantification real time PCR method in the YSM and embryonic intestine. Different temporal patterns of expression were observed for these genes. The effect of in ovo injection of peptides (the dipeptide Gly-Sar, purified peptides, trypsin hydrolysate) on transporter gene expression has been examined in the embryonic intestine. Injection of a partial protein hydrolysate resulted in an increase in expression of the peptide transporter PepT2. We have initiated a transcriptome analysis of genes expressed in the YSM at different developmental ages to better understand the function of the YSM.
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Barefoot, Susan F., Bonita A. Glatz, Nathan Gollop, and Thomas A. Hughes. Bacteriocin Markers for Propionibacteria Gene Transfer Systems. United States Department of Agriculture, June 2000. http://dx.doi.org/10.32747/2000.7573993.bard.

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The antibotulinal baceriocins, propionicin PLG-1 and jenseniin G., were the first to be identified, purified and characterized for the dairy propionibaceria and are produced by Propionibacterium thoenii P127 and P. thoenii/jensenii P126, respectively. Objectives of this project were to (a) produce polyclonal antibodies for detection, comparison and monitoring of propionicin PLG-1; (b) identify, clone and characterize the propionicin PLG-1 (plg-1) and jenseniin G (jnG) genes; and (3) develop gene transfer systems for dairy propionibacteria using them as models. Polyclonal antibodies for detection, comparison and monitoring of propionicin PLG-1 were produced in rabbits. Anti-PLG-1 antiserum had high titers (256,000 to 512,000), neutralized PLG-1 activity, and detected purified PLG-1 at 0.10 mg/ml (indirect ELISA) and 0.033 mg/ml (competitive indirect ELISA). Thirty-nine of 158 strains (most P. thoenii or P. jensenii) yielded cross-reacting material; four strains of P. thoenii, including two previously unidentified bacteriocin producers, showed biological activity. Eight propionicin-negative P127 mutants produced neither ELISA response nor biological activity. Western blot analyses of supernates detected a PLG-1 band at 9.1 kDa and two additional protein bands with apparent molecular weights of 16.2 and 27.5 kDa. PLG-1 polyclonal antibodies were used for detection of jenseniin G. PLG-1 antibodies neutralized jenseniin G activity and detected a jenseniin G-sized, 3.5 kDa peptide. Preliminary immunoprecipitation of crude preparations with PLG-1 antibodies yielded three proteins including an active 3-4 kDa band. Propionicin PLG-1 antibodies were used to screen a P. jensenii/thoenii P126 genomic expression library. Complete sequencing of a cloned insert identified by PLG-1 antibodies revealed a putative response regulator, transport protein, transmembrane protein and an open reading frame (ORF) potentially encoding jenseniin G. PCR cloning of the putative plg-1 gene yielded a 1,100 bp fragment with a 355 bp ORF encoding 118 amino acids; the deduced N-terminus was similar to the known PLG-1 N-terminus. The 118 amino acid sequence deduced from the putative plg-1 gene was larger than PLG-1 possibly due to post-translational processing. The product of the putative plg-1 gene had a calculated molecular weight of 12.8 kDa, a pI of 11.7, 14 negatively charged residues (Asp+Glu) and 24 positively charged residues (Arg+Lys). The putative plg-1 gene was expressed as an inducible fusion protein with a six-histidine residue tag. Metal affinity chromatography of the fused protein yielded a homogeneous product. The fused purified protein sequence matched the deduced putative plg-1 gene sequence. The data preliminarily suggest that both the plg-1 and jnG genes have been identified and cloned. Demonstrating that antibodies can be produced for propionicin PLG-1 and that those antibodies can be used to detect, monitor and compare activity throughout growth and purification was an important step towards monitoring PLG-1 concentrations in food systems. The unexpected but fortunate cross-reactivity of PLG-1 antibodies with jenseniin G led to selective recovery of jenseniin G by immunoprecipitation. Further refinement of this separation technique could lead to powerful affinity methods for rapid, specific separation of the two bacteriocins and thus facilitate their availability for industrial or pharmaceutical uses. Preliminary identification of genes encoding the two dairy propionibacteria bacteriocins must be confirmed; further analysis will provide means for understanding how they work, for increasing their production and for manipulating the peptides to increase their target species. Further development of these systems would contribute to basic knowledge about dairy propionibacteria and has potential for improving other industrially significant characteristics.
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Chen, Chiung-Chu, and Michael McQuaid. A Thermochemical Kinetic-Based Study of Ignition Delays for 2-Azidoethanamine-Red Fuming Nitric Acid Systems: 2-Azido-N-Methylethanamine (MMAZ) Vs. 2-Azido-N,N-Dimethylethanamine (DMAZ). Fort Belvoir, VA: Defense Technical Information Center, January 2014. http://dx.doi.org/10.21236/ada599206.

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