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Bibliografias temáticas / Molecular selectivity

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Literatura científica selecionada sobre o tema "Molecular selectivity"

Autor: Grafiati

Publicado: 21 de dezembro de 2024

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Artigos de revistas sobre o assunto "Molecular selectivity"

1

Murray, Royce. "Chemical Sensors and Molecular Selectivity". Analytical Chemistry 66, n.º 9 (abril de 1994): 505a. http://dx.doi.org/10.1021/ac00081a600.

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Somorjai, Gabor A, e Jeong Y Park. "Molecular Factors of Catalytic Selectivity". Angewandte Chemie International Edition 47, n.º 48 (12 de novembro de 2008): 9212–28. http://dx.doi.org/10.1002/anie.200803181.

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Liu, Guangyang, Xiaodong Huang, Lingyun Li, Xiaomin Xu, Yanguo Zhang, Jun Lv e Donghui Xu. "Recent Advances and Perspectives of Molecularly Imprinted Polymer-Based Fluorescent Sensors in Food and Environment Analysis". Nanomaterials 9, n.º 7 (18 de julho de 2019): 1030. http://dx.doi.org/10.3390/nano9071030.

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Molecular imprinting technology (MIT), also known as molecular template technology, is a new technology involving material chemistry, polymer chemistry, biochemistry, and other multi-disciplinary approaches. This technology is used to realize the unique recognition ability of three-dimensional crosslinked polymers, called the molecularly imprinted polymers (MIPs). MIPs demonstrate a wide range of applicability, good plasticity, stability, and high selectivity, and their internal recognition sites can be selectively combined with template molecules to achieve selective recognition. A molecularly imprinted fluorescence sensor (MIFs) incorporates fluorescent materials (fluorescein or fluorescent nanoparticles) into a molecularly imprinted polymer synthesis system and transforms the binding sites between target molecules and molecularly imprinted materials into readable fluorescence signals. This sensor demonstrates the advantages of high sensitivity and selectivity of fluorescence detection. Molecularly imprinted materials demonstrate considerable research significance and broad application prospects. They are a research hotspot in the field of food and environment safety sensing analysis. In this study, the progress in the construction and application of MIFs was reviewed with emphasis on the preparation principle, detection methods, and molecular recognition mechanism. The applications of MIFs in food and environment safety detection in recent years were summarized, and the research trends and development prospects of MIFs were discussed.

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Candeago, Riccardo, Hanyu Wang, Manh-Thuong Nguyen, Mathieu Doucet, Vassiliki Alexandra Glezakou, Jim Browning e Xiao Su. "Molecular Insights into Redox-Active Polymer Interfaces: Solvation and Ion Valency Effects on Metal Oxyanion Selectivity". ECS Meeting Abstracts MA2024-01, n.º 55 (9 de agosto de 2024): 2910. http://dx.doi.org/10.1149/ma2024-01552910mtgabs.

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Chemical separations are responsible for 10-15% of the world’s energy consumption. Minimizing energy and materials inputs in selective separations is imperative for a sustainable future. Ion-electrosorption mediated by redox-active metallopolymer interfaces has the unique advantage of selectively capturing and releasing metal oxyanions in a switchable manner by adjusting the applied potential, without any regenerants. Electrosorption addresses the need for selective separation approaches with low chemical and energy inputs. Previous studies on ferrocene metallopolymers have demonstrated the role of polymer structure and applied potential on selectivity—however, the ubiquitous role of solvation in redox-polymers has remained unexplored. Here, we investigate how solvation and ion valency influence selectivity of ReO4 - vs MoO4 2- for two redox-metallopolymers, poly(vinyl ferrocene) (PVFc) and poly(3-ferrocenylpropyl methacrylamide) (PFPMAm). Both polymers display time-dependent Re/Mo selectivity, with PVFc having higher selectivity compared to PFPMAm. Operando neutron reflectometry, ellipsometry, and electrochemical quartz-crystal microbalance show that both PVFc and PFPMAm swell in the presence of ReO4 - (with PFPMAm having higher solvation), but do not swell in contact with MoO4 2-. We find that the less solvated anion (ReO4 -) is preferably adsorbed by the more hydrophobic redox-polymer (PVFc). We expect that a deeper understanding of solvation and valency effects on selectivity mechanisms in redox interfaces will expedite the development of targeted selective ion-electrosorption systems. Figure 1

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Rauschenberg, Melanie, Eva-Corrina Fritz, Christian Schulz, Tobias Kaufmann e Bart Jan Ravoo. "Molecular recognition of surface-immobilized carbohydrates by a synthetic lectin". Beilstein Journal of Organic Chemistry 10 (16 de junho de 2014): 1354–64. http://dx.doi.org/10.3762/bjoc.10.138.

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The molecular recognition of carbohydrates and proteins mediates a wide range of physiological processes and the development of synthetic carbohydrate receptors (“synthetic lectins”) constitutes a key advance in biomedical technology. In this article we report a synthetic lectin that selectively binds to carbohydrates immobilized in a molecular monolayer. Inspired by our previous work, we prepared a fluorescently labeled synthetic lectin consisting of a cyclic dimer of the tripeptide Cys-His-Cys, which forms spontaneously by air oxidation of the monomer. Amine-tethered derivatives of N-acetylneuraminic acid (NANA), β-D-galactose, β-D-glucose and α-D-mannose were microcontact printed on epoxide-terminated self-assembled monolayers. Successive prints resulted in simple microarrays of two carbohydrates. The selectivity of the synthetic lectin was investigated by incubation on the immobilized carbohydrates. Selective binding of the synthetic lectin to immobilized NANA and β-D-galactose was observed by fluorescence microscopy. The selectivity and affinity of the synthetic lectin was screened in competition experiments. In addition, the carbohydrate binding of the synthetic lectin was compared with the carbohydrate binding of the lectins concanavalin A and peanut agglutinin. It was found that the printed carbohydrates retain their characteristic selectivity towards the synthetic and natural lectins and that the recognition of synthetic and natural lectins is strictly orthogonal.

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Farman, Nicolette, e Brigitte Bocchi. "Mineralocorticoid selectivity: Molecular and cellular aspects". Kidney International 57, n.º 4 (abril de 2000): 1364–69. http://dx.doi.org/10.1046/j.1523-1755.2000.00976.x.

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Comba, Peter. "Metal ion selectivity and molecular modeling". Coordination Chemistry Reviews 185-186 (maio de 1999): 81–98. http://dx.doi.org/10.1016/s0010-8545(98)00249-5.

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8

Laskin, Julia, Alexander Laskin, Sergey A. Nizkorodov, Patrick Roach, Peter Eckert, Mary K. Gilles, Bingbing Wang, Hyun Ji (Julie) Lee e Qichi Hu. "Molecular Selectivity of Brown Carbon Chromophores". Environmental Science & Technology 48, n.º 20 (7 de outubro de 2014): 12047–55. http://dx.doi.org/10.1021/es503432r.

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Epa, Kanishka, Christer B. Aakeröy, John Desper, Sundeep Rayat, Kusum Lata Chandra e Aurora J. Cruz-Cabeza. "Controlling molecular tautomerism through supramolecular selectivity". Chemical Communications 49, n.º 72 (2013): 7929. http://dx.doi.org/10.1039/c3cc43935f.

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Souverijns, Wim, Lieve Rombouts, Johan A. Martens e Pierre A. Jacobs. "Molecular shape selectivity of EUO zeolites". Microporous Materials 4, n.º 2-3 (junho de 1995): 123–30. http://dx.doi.org/10.1016/0927-6513(94)00091-9.

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Teses / dissertações sobre o assunto "Molecular selectivity"

1

Rajbanshi, Arbin. "Supramolecular interactions from small-molecule selectivity to molecular capsules". Diss., Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/3879.

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Bouanga, Boudiombo Jacky Sorrel. "Molecular selectivity by host-guest methods". Doctoral thesis, Faculty of Science, 2021. http://hdl.handle.net/11427/33667.

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The Host-Guest inclusion crystallization method has long been used for the separation of closely related compounds. Especially for the separation of isomers which presented difficulties in techniques like distillation or chromatography. In this study, different host systems were used to separate isomers of trimethoxybenzenes, lutidines, methylacetophenones and xylenols. Isomers are compounds with the same molecular formula but different arrangement of their atoms. They are often produced as mixtures when synthesised in large quantities by various industries and are more valuable as purified single components. Thus, it is important to separate them into their individual components. The process of Host-Guest method is dependent on the phenomenon of molecular recognition between the host and guest molecules, and this, in turn, relies on the sum of non-bonded, secondary interactions which impinge on the final crystalline product. This is especially the case for enantiomers which are isomers with the same boiling points and melting point. However, enantiomers differ by their ability to diffract polarised light. Although countless methods have been used for their separation, one method that has been proven to be certainly successful on this path was the “family method”. The “Dutch resolution method” or the “family method” makes use of the crystallization technique by mixing similar host compounds to separate enantiomers. However, the improvement of the end results was not understood. In fact, the whole process has been done just on results and no analysis of the actual activity occurring at the molecular level was investigated. In this research, the Host-Guest chemistry method was applied with the aim of separating several isomers compounds in the intention of understanding the selectivity characteristics of a particular host. For the purpose of the analysis, structural isomers with close boiling points were selected. Competition experiments were set to survey which of the isomers were a better fit for a particular host. After analysis of the different crystal material obtained from crystallization experiments with NMR techniques, various trends were observed. X-Ray crystallography was employed to elucidate the crystal structures of the different compound formed by Host-Guest chemistry. The new complexes were further analysed by thermal analysis (TGA, DSC), kinetics of desolvation, Hirshfeld surface analysis, and activation energy of desolvation-analysis techniques. During the separation of the trimethoxybenzene (TMB) isomers, cholic acid and deoxycholic acid' hosts were used in chapter 3. It was found that each host separated the isomers differently. That was independent of the closeness of their molecular structures. The difference in selectivity was attributed to the arrangement of each host in the structure obtained with the guest compounds. Separation of lutidines was carried out in chapters 4 and 5. The first separation consisted of the study of the fifteen pairwise combinations of the isomers with 3,3′-bis(9-hydroxy-9- fluorenyl)2−2′- binaphthyl which is presented in chapter 4. The second analysis was carried out with host 2,2'bis(1-hydroxy-4,5-dihydro-2,3:6,7-dibenzocycloheptatrien-1-yl)-biphenyl. Nevertheless, both hosts preferred 3,4-lutidine. Four additional hosts were used to simulate the “Dutch resolution method” in chapter 5. Further analysis of torsion angles was performed over the five hosts for the complexes formed with 2,4-lutidine and 3,5-lutidine. The host characterized by unbridged phenyl moieties and the one characterized by bulky tert-butyl groups was found to prefer 3,5-lutidine. In chapter 6, deoxycholic acid resolved the 2-methylcyclohexanone (2MCH) but not 3- methylcyclohexanone (3MCH) during the separation of methylcyclohexanone isomers. However, during the competition experiment, it was found that when 2MCH was mixed with 3MCH, the latter was resolved as an S-enantiomer. Kinetics of desolvation studied resulted in the determination of the activation energies of the Host-Guest complexes and was like the trend observed by 1H NMR analysis. Chapter 7 was focused on the synergistic effect of mixed hosts system. This was to emphasize the impact that a mixture of compounds with similar structural composition may provide. Competition experiments were done with the 15 pairs of xylenol isomers with 4,4'- isopropylidene Bisphenol. Three of these pairs were selected for further analysis with two similar bisphenol hosts. One interesting structure was obtained with 4,4-isopropylidene Bisphenol and 4,4'-(9-Fluorenylidene) Bisphenol with a guest mixture. This is an unusual result as crystal structures comprising two hosts with two guests are rare.

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Fransson, Linda. "Molecular modelling - understanding and prediction of enzyme selectivity". Licentiate thesis, KTH, School of Biotechnology (BIO), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10532.

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Molecular modelling strategies for evaluation of enzyme selectivity wereinvestigated with a focus on principles of how molecular interactionscould be evaluated to provide information about selectivity. Althoughmolecular modelling provides tools for evaluation of geometrical andenergy features of molecular systems, no general strategies for evaluationof enzyme selectivity exist. Geometrical analyses can be based uponinspection and reasoning about molecular interactions, which provide aneasily accessible way to gain information, but suffer from the risk of biasput in by the modeller. They can also be based on geometrical features ofmolecular interactions such as bond lengths and hydrogen-bond formation.Energy analyses are appealing for their modeller independenceand for the possibility to predict not only stereopreference, but also itsmagnitude.In this thesis, four examples of enantio- or regioselective serinehydrolase-catalysed reaction systems are presented together with developedmodelling protocols for explanation, prediction or enhancement ofselectivity. Geometrical as well as energy-based methodology were used,and provided an understanding of the structural basis of enzymeselectivity. In total, the protocols were successful in making qualitative explanationsand predictions of stereoselectivity, although quantitative determinationswere not achieved.

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Heung, Yen Ming Mary. "Molecular selectivity of phospholipase D in granulocyte function". Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241935.

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Maughfling, Edward John Rosewarne. "Molecular basis for the ligand selectivity of bombesin receptors". Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.625098.

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Bauer, Paul. "Computational modelling of enzyme selectivity". Doctoral thesis, Uppsala universitet, Struktur- och molekylärbiologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-326108.

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Enantioselective reactions are one of the ways to produce pure chiral compounds. Understanding the basis of this selectivity makes it possible to guide enzyme design towards more efficient catalysts. One approach to study enzymes involved in chiral chemistry is through the use of computational models that are able to simulate the chemical reaction taking place. The potato epoxide hydrolase is one enzyme that is known to be both highly enantioselective, while still being robust upon mutation of residues to change substrate scope. The enzyme was used to investigate the epoxide hydrolysis mechanism for a number of different substrates, using the EVB approach to the reaction both in solution and in several enzyme variants. In addition to this, work has been performed on new ways of performing simulations of divalent transition metals, as well as development of new simulation software.

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7

Erlenbach, Isolde. "The molecular basis of V2 vasopressin receptor-G protein coupling selectivity". [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963474448.

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8

Kröger, Wendy Lee. "A molecular basis for the C-domain selectivity of angiotensin-converting enzyme". Doctoral thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/3134.

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Kroger, W. "A Molecular Basis for the C-Domain Selectivity of Angiotensin-Converting Enzyme". Doctoral thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/3135.

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Angiotensin-Converting Enzyme (ACE) plays an essential role in blood pressure regulationand ACE inhibitors are widely used to treat cardiovascular disease. Two isoforms exist,somatic ACE (sACE) consisting of two homologous domains, N- and C-domain, and testisACE (tACE), corresponding to the C-domain of sACE. Despite a high degree of sequenceidentity, these two domains display marked differences in substrate and inhibitor specificity.Furthermore, the C-domain of ACE has been implicated to play a dominant role in bloodpressure control. It has therefore been suggested that development of ACE inhibitortreatments that selectively block the C-domain will result in decreased side-effects comparedto current therapies. Analysis of three-dimensional structures of tACE in complex withdomain-specific inhibitors has enabled the identification of key active-site residues potentiallyplaying a role in domain selectivity. To investigate the contribution of such residues, a seriesof C-domain mutants was generated containing single and multiple N-domain active-sitesubstitutions. These constructs were used to characterise specific interactions using domainselectiveinhibitors and fluorogenic peptides. Mutants tested with the fluorogenic peptidesdisplayed minimal, if any, acquisition of N-domain-like catalytic properties. Of the singlemutations, S2 (F391Y, tACE numbering) and S1 (V518T) pocket substitutions caused thelargest decreases in affinity for the C-selective phosphinic inhibitor RXPA380 (34-fold) andketo-ACE derivatives (14-26 fold), respectively. The V379S mutation caused an unexpectedincrease in affinity (2-10 fold) for C-selective inhibitors containing a P2’ Trp that could beexplained by the formation of a water-mediated hydrogen bond interaction resulting fromrearrangement of inhibitor and protein side-chains within the S2’ pocket. Multiple mutantscontaining an N-domain-like S2’ pocket combined with the S2 F391Y substitution (S2’F)caused the most notable shift in Ki from that of tACE for the highly selective phosphinicinhibitors, RXPA380 (Ki’s tACE = 69 nM; S2’F = 5300 nM) and N-specific RXP407 (Ki’stACE = 2800 nM; S2’F Ki = 16.1 nM). This work identifies key residues contributing to thedomain selectivity of ACE, and highlights the complex combination of effects involved in thisphenomenon. Furthermore, it provides useful insight for the further design of domainselectiveinhibitors.

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Blgacim, Nuria. "Molecular Control of the δ-opioid Receptor Signaling and Functional Selectivity by Sodium". Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37806.

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Accumulating evidence suggests a prominent role of the arrestin-dependent signaling pathway in triggering most of the deleterious side effects observed using δ-OR targeting drugs. Numerous small molecules targeting the δ-OR receptors have been developed but their pharmacological properties, including their functional selectivity, have been poorly characterized. The absence of functionally selective opioid drugs, and the lack of knowledge of the pharmacological profile and signaling properties of the δ-OR receptor, limits its therapeutic exploitation. The development of functionally selective modulator toward the canonical G protein pathway could importantly increase the therapeutic potential of this receptor while decreasing its deleterious effects. An approach to fine-tune the functional selectivity of a GPCR is by using allosteric modulators. These allosteric modulators would reduce problems associated with drugs targeting the orthosteric site by not chronically activating the receptor. The overall goal of the proposed research is to study the molecular mechanism by which sodium-channel inhibitors allosterically regulates the delta opioid receptor (δ-OR) signaling and functional selectivity. Additionally, the signaling features of the δ-OR signal transduction triggered by biased receptor activation have been investigated. A combination of approaches, including functional studies, molecular modeling and mutagenesis, were used to study the general mechanism underlying the activation and tuning of the δ-OR signal transduction behavior. Thus, this work suggests the druggability of the allosteric sodium pocket by using sodium channel inhibitors. The current research represent discovery of two different allosteric profiles for the β-arrestin recruitment and one allosteric profile for the G-protein pathway at activated DOR and would serve as scaffold for further refinement of modulators with the desired pharmacological profile.

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Livros sobre o assunto "Molecular selectivity"

1

Hathway, D. E. Molecular mechanisms of herbicide selectivity. Oxford: Clarendon, 1989.

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2

De Matteis, F., e E. A. Lock. Selectivity and Molecular Mechanisms of Toxicity. London: Palgrave Macmillan UK, 1987. http://dx.doi.org/10.1007/978-1-349-08759-4.

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A, Lock E., ed. Selectivity and molecular mechanisms of toxicity. Basingstoke: Macmillan, 1987.

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4

Sokell, Emma Jane. A study of decay route selectivity in atomic and molecular autoionisation using two-dimensional photoelectron spectroscopy. Manchester: University of Manchester, 1995.

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5

Crowe, Declan Brendan. Macrocyclic host molecules designed to selectively bind and transport ammonium and primary ammonium guest cations. Birmingham: University of Birmingham, 1991.

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6

Molecular mechanisms of herbicide selectivity. Oxford [England]: Oxford University Press, 1989.

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7

(Editor), E. A. Lock, ed. Selectivity and Molecular Mechanisms of Toxicity. Macmillan Pub Co, 1987.

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8

Matteis, Francesco De, e Edward A. Lock. Selectivity and Molecular Mechanisms of Toxicity. Palgrave Macmillan, 1987.

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9

Knaggs, Roger D. The molecular structure of the μ‎-opioid receptor. Editado por Paul Farquhar-Smith, Pierre Beaulieu e Sian Jagger. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198834359.003.0038.

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The landmark paper discussed in this chapter describes the crystal structure of the μ‎-opioid receptor (also known as MOP-1). Opioids are some of the oldest known drugs and have been used for over 4,000 years; however, in addition to having beneficial analgesic effects, they are associated with a myriad of side effects that can minimize their use. Although the gene sequences of the opioid receptors were determined in the 1990s it has taken much longer to translate this into visualizing their three-dimensional structure. The μ‎-opioid receptor consists of seven transmembrane α‎-helices that are connected by three extracellular loops and three intracellular loops, with a wide open binding pocket which offers many potential ligand interaction sites, and evidence of dimerization. Understanding the crystal structure of the μ‎-opioid receptor in much more detail aids explanation of the molecular determinants of ligand recognition and selectivity and will be of use in designing novel opioids with improved efficacy and fewer side effects.

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10

Molecular dipoles in non-polar solvent: A mechanistic investigation of complexation phenomena and selectivity in asymmetric urea-super acid cocatalysis. 2010.

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Capítulos de livros sobre o assunto "Molecular selectivity"

1

Guengerich, F. Peter. "Sequence Selectivity of DNA Damage". In Molecular Life Sciences, 1–3. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4614-6436-5_214-1.

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Guengerich, Frederick Peter. "Sequence Selectivity of DNA Damage". In Molecular Life Sciences, 1126–28. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4614-1531-2_214.

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Nassimbeni, L. R. "Inclusion Compounds: Kinetics and Selectivity". In Molecular Recognition and Inclusion, 135–52. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5288-4_16.

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Ferrie, Ann M., Vasiliy Goral, Chaoming Wang e Ye Fang. "Label-Free Functional Selectivity Assays". In Methods in Molecular Biology, 227–46. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4939-2336-6_16.

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Stace, A. J., e D. M. Bernard. "Reactions of Molecular Ions in Association with Inert Gas Clusters". In Selectivity in Chemical Reactions, 365–72. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-3047-6_20.

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6

Guengerich, F. Peter. "Selectivity of Chemicals for DNA Damage". In Molecular Life Sciences, 1–3. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4614-6436-5_163-1.

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Guengerich, Frederick Peter. "Selectivity of Chemicals for DNA Damage". In Molecular Life Sciences, 1111–13. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4614-1531-2_163.

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Breslow, R. "Biomimetic Control of Chemical Selectivity". In Design and Synthesis of Organic Molecules Based on Molecular Recognition, 185–97. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-70926-5_15.

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Stumpfe, Dagmar, Eugen Lounkine e Jürgen Bajorath. "Molecular Test Systems for Computational Selectivity Studies and Systematic Analysis of Compound Selectivity Profiles". In Methods in Molecular Biology, 503–15. Totowa, NJ: Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-839-3_20.

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10

Watts, Anthony. "Molecular Dynamics and Selectivity in Biomembranes". In Membrane Receptors, Dynamics, and Energetics, 329–39. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4684-5335-5_28.

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Trabalhos de conferências sobre o assunto "Molecular selectivity"

1

Russo, Michael J., Simon H. Friedman, Jens O. M. Karlsson e Mehmet Toner. "A Two-Compartment Membrane Limited Model of Molecular Transport Through Nano-Scale Pores With a Metal-Actuated Switch". In ASME 1997 International Mechanical Engineering Congress and Exposition, 9–14. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-1306.

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Abstract We have previously demonstrated that we can reversibly alter the transport selectivity of the plasma membrane to small molecules (∼1000 Da) by treating cells with H5, a genetic mutant of the pore-forming protein Staphylococcus aureus α-toxin, designed to be equipped with a metal-actuated switch. Toward the development of a plasma membrane permeabilization technique for both clinical and basic research applications, we have developed a simple model of molecular transport through the H5 pore. This model in combination with hindered transport models predicts the rate of transport of our marker molecules, carboxycalcein blue (CCB) and sucrose, and provides an approximation of the number of pores in the plasma membrane. Model predictions are also in reasonable agreement with experimental measurements of CCB and sucrose transport through the H5 treated plasma membranes of 3T3 fibroblasts. This model allows us to analyze quantitatively the selectivity of the H5 pore and by extension to use genetically designed pore forming proteins to advance the understanding of hindered transport in pores.

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2

Ramachandran, Abhijit, Qingjiang Guo, Samir Iqbal e Yaling Liu. "Modeling DNA Translocation Kinetics in Nanopores With Selectivity". In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13074.

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The development in nanotechnology has made fabrication of solid-state nanopores with 20nm diameter possible. These nanopores have found a variety of applications, with the foremost one being sensing of the biological molecules. To achieve molecular sensing, a major requirement of these solid state nanopores is molecular selectivity. This paper focuses on modeling the DNA translocation in functionalized nanopore with application on gene sequencing.

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3

Vitale, U., A. Rechichi, M. D’Alonzo, C. Cristallini, N. Barbani, G. Ciardelli e P. Giusti. "Selective Peptide Recognition With Molecularly Imprinted Polymers in Designing New Biomedical Devices". In ASME 8th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2006. http://dx.doi.org/10.1115/esda2006-95587.

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Molecular imprinting is a technique for the synthesis of polymers capable to bind selectively specific molecules. The imprinting of large proteins, like cell adhesion proteins or cell receptors, can lead to important and innovative biomedical applications. However such molecules show such important conformational changes in the polymerisation environment that the recognition sites are poorly specific. The “epitope approach” can overcome this limit by adopting, as template, a stable short peptide sequence representative of an accessible fragment of a larger protein. The resulting imprinted polymer can recognize both the template and the whole molecule thanks to the specific cavities for the epitope. In this work two molecularly imprinted polymer formulations (macroporous monolith and nanospheres) were obtained with the protected peptides Z-Thr-Ala-Ala-OMe, as template, and Z-Thr-Ile-Leu-OMe, as analogue for the selectivity evaluation, the methacrylic acid, as functional monomer, the trimethylolpropane trimethacrylate and pentaerythritol triacrylate, as cross-linkers. Polymers were synthesized by precipitation polymerisation in acetonitrile at 60 °C, thermally initiated with azobisisobutyronitrile. All polymers were characterized by the standard techniques SEM, FT-IR, and TGA. The supernatants from the polymerisation and the rebinding solutions were analysed by HPLC. The higher cross-linked polymers retained about the 70% of the template, against about the 20% for the lower ones. The extracted template amount and the rebinding capacity decreased with the cross-linking degree, while the selectivity showed the opposite behaviour. The pentaerythritol triacrylate cross-linked polymers showed the best recognition (MIP 2−, α = 1.71) and selectivity (MIP 2+, α′ = 5.58) capabilities.

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4

Cannon, James J., Dai Tang e Daejoong Kim. "A Molecular Dynamics Study on the Absorption of Ions Into Carbon Nanotubes". In ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30579.

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The ability of ions to be selectively absorbed into nano-pores is important for a wide range of industrial and biological processes. To make practical use of such ionic selectivity, a molecular-level understanding of the dynamics is required, so that conditions can be tailored and optimised as required. This is especially the case when the ions being separated are very similar. We have therefore conducted molecular dynamics simulations in order to study the selective absorption of sodium and potassium ions into a nano-scale pore. We show how ion hydration and the presence of a negative ion lead to alternative selectivity depending on the size of the pore.

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5

Zia, Asif I., S. C. Mukhopadhyay, I. H. Al-Bahadly, P. L. Yu, Chinthaka P. Gooneratne e Jurgen Kosel. "Introducing molecular selectivity in rapid impedimetric sensing of phthalates". In 2014 IEEE International Instrumentation and Measurement Technology Conference (I2MTC). IEEE, 2014. http://dx.doi.org/10.1109/i2mtc.2014.6860861.

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Wadman, Grant, Irina Kufareva, John Dawson, Penglie Zhang, Andrew Tebben, Percy Carter, Siyi Gu et al. "Molecular Mechanisms of Antagonist Selectivity Against CCR2 and CCR5". In ASPET 2024 Annual Meeting Abstract. American Society for Pharmacology and Experimental Therapeutics, 2024. http://dx.doi.org/10.1124/jpet.569.131403.

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Weiner, A. M., D. E. Leaird, G. P. Wiederrecht e K. A. Nelson. "Femtosecond multiple pulse impulsive simulated Raman scattering in α-perylene molecular crystals". In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.fx5.

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Generation of coherent optic phonons through impulsive stimulated Raman scattering (ISRS) can occur whenever a sufficiently short optical pulse passes through a Raman active medium. The first experiments demonstrating ISRS were performed with α-perylene molecular crystals1; subsequently, similar observations were reported for a variety of other materials. One difficulty which can be associated with the impulsive scattering technique is an inherent lack of mode selectivity. In this paper we demonstrate multiple pulse impulsive stimulated Raman scattering, a powerful new technique for achieving mode selectivity in ISRS experiments. By using phase-only spectral filtering techniques, we efficiently generate terahertz repetition-rate bursts of femtosecond pulses,2 which we use for repetitive impulsive excitation in our experiments. Individual phonon modes are selected by tuning the pulse repetition rate to the vibrational period. We demonstrate this concept by selectively and individually exciting the 104-cm™1 vibrational mode and the 80-cm™1 librational mode in α-perylene molecular crystals. This technique permits direct observation of the individual cycles of the vibrational and librational oscillations, without the mode beating which occurred in previous experiments,1 and makes possible accurate measurements of the dephasing times.

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Tarhan, M. C., R. Yokokawa, F. O. Morin, S. Takeuchi e H. Fujita. "Sorting and direct transportation of target molecules by bio-molecular selectivity and motor function". In 2007 IEEE 20th International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2007. http://dx.doi.org/10.1109/memsys.2007.4433049.

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Higgins, M. J., M. Polcik, T. Fukuma, J. E. Sader e S. P. Jarvis. "Direct Mechanical Measurement of Organised Water and the Influence of Adjacent Surface Chemistry Using Atomic Force Microscopy (Keynote)". In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-64383.

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Directly measuring structural changes in water with a mechanical probe of lateral dimensions comparable to that of a single molecule provides an invaluable insight into how and why bio-molecules behave with high selectivity or why certain surfaces promote or inhibit bio-molecular adhesion. In the immediate vicinity of the molecule, continuum models break down and the aqueous environment will often form a discrete layered structure depending on the nature of the molecule. The absence or presence of such structure may be fundamental in influencing the promotion or inhibition of protein adsorption, biological function and membrane recognition.

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Kessler, Rudolf. "Sensitivity and selectivity in optical spectroscopy and imaging: A molecular approach". In OCM 2015 - 2nd International Conference on Optical Characterization of Materials. KIT Scientific Publishing, 2015. http://dx.doi.org/10.58895/ksp/1000044906-7.

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Intelligent manufacturing has attracted enormous interest in recent years. Optical spectroscopy will play a major role in the sensor technology as it provides simultaneously chemical (by absorption) and morphological (by scatter) information. The paper demonstrates, that the sensitivity and selectivity of each individual technology has its limitations due to the structure of the molecule and the quantum mechanical limitations by their interaction with the photons. The absorption and scatter cross sections are defined and discussed in terms of sensitivity and selectivity of the different technologies. These fundamentals cannot be overcome. Furthermore, the suitability and robustness of each technology is pre-determined by the selection of appropriate light illumination sources and the selected detectors. An overview of the different techniques is given.

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Relatórios de organizações sobre o assunto "Molecular selectivity"

1

Rigali, Mark J., e Thomas Austin Stewart. Evaluation of Strontium Selectivity by Sandia Octahedral Molecular Sieves (SOMS). Office of Scientific and Technical Information (OSTI), janeiro de 2016. http://dx.doi.org/10.2172/1236112.

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Ivanov, Aleksandr, Sadananda Das, Vyacheslav Bryantsev, Costas Tsouris, Austin Ladshaw e Sotira Yiacoumi. Predicting Selectivity of Uranium vs. Vanadium from First Principles: Complete Molecular Design and Adsorption Modeling. Office of Scientific and Technical Information (OSTI), julho de 2017. http://dx.doi.org/10.2172/1454410.

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Gurevitz, Michael, Michael E. Adams e Boaz Shaanan. Structural Elements and Neuropharmacological Features Involved in the Insecticidal Properties of an Alpha Scorpion Neurotoxin: A Multidisciplinary Approach. United States Department of Agriculture, agosto de 1995. http://dx.doi.org/10.32747/1995.7573061.bard.

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Integrated pest management in modern crop protection requires the use of chemical or biological insecticides in many instances. Nontheless, the use non-selective chemical insecticides poses risks to the environment and livestock and consequently urgent need exists for safer alternatives, which target insects more specifically. Scorpions produce anti-insect selective polypeptide toxins that are biodegradable and not toxic to wam-blooded animals. Therefore, mobilization of these substances into insect pest targets is of major interest. Moreover, clarification of the molecular basis of this selectivity may provide valuable information pertinent to their receptor sites and to the future design of peptidomimetic anti-insect specific substances. These toxins may also be important for reducing the current overuse of chamical insecticides provided they have a synergistic effect with conventional pesticides. All of these objectives were addressed in this research. A direct approach for plant protection was the mobilization of toxins into target pests using baculoviral vectors. The other approach was to develop a suitable system enabling the elucidation of the toxin bioactive site, which would enable design of insecticidal peptidomimetics. In parallel, the mode of action and synergistic effects of scorpion insecticidal toxins, were studied at the sodium channel receptor site. All the above approaches show great promise and clearly indicate that scorpion insecticidal toxins may provide powerful means in insect pest control.

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Gurevitz, Michael, Michael E. Adams, Boaz Shaanan, Oren Froy, Dalia Gordon, Daewoo Lee e Yong Zhao. Interacting Domains of Anti-Insect Scorpion Toxins and their Sodium Channel Binding Sites: Structure, Cooperative Interactions with Agrochemicals, and Application. United States Department of Agriculture, dezembro de 2001. http://dx.doi.org/10.32747/2001.7585190.bard.

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Integrated pest management in modern crop protection may combine chemical and biological insecticides, particularly due to the risks to the environment and livestock arising from the massive use of non-selective chemicals. Thus, there is a need for safer alternatives, which target insects more specifically. Scorpions produce anti-insect selective polypeptide toxins that are biodegradable and non-toxic to warm-blooded animals. Therefore, integration of these substances into insect pest control strategies is of major importance. Moreover, clarification of the molecular basis of this selectivity may provide valuable information pertinent to their receptor sites and to the future design of peptidomimetic anti-insect specific substances. These toxins may also be important for reducing the current overuse of chemical insecticides if they produce a synergistic effect with conventional pesticides. Based on these considerations, our major objectives were: 1) To elucidate the three-dimensional structure and toxic-site of scorpion excitatory, "depressant, and anti-insect alpha toxins. 2) To obtain an initial view to the sodium channel recognition sites of the above toxins by generating peptide decoys through a phage display system. 3) To investigate the synergism between toxins and chemical insecticides. Our approach was to develop a suitable expression system for toxin production in a recombinant form and for elucidation of toxin bioactive sites via mutagenesis. In parallel, the mode of action and synergistic effects of scorpion insecticidal toxins with pyrethroids were studied at the sodium channel level using electrophysiological methods. Objective 1 was achieved for the alpha toxin, LqhaIT Zilberberg et al., 1996, 1997; Tugarinov et al., 1997; Froy et al., 2002), and the excitatory toxin, Bj-xtrIT (Oren et al., 1998; Froy et al., 1999; unpublished data). The bioactive surface of the depressant toxin, LqhIT2, has been clarified and a crystal of the toxin is now being analyzed (unpublished). Objective 2 was not successful thus far as no phages that recognize the toxins were obtained. We therefore initiated recently an alternative approach, which is introduction of mutations into recombinant channels and creation of channel chimeras. Objective 3 was undertaken at Riverside and the results demonstrated synergism between LqhaIT or AaIT and pyrethroids (Lee et al., 2002). Furthermore, negative cross-resistance between pyrethroids and scorpion toxins (LqhaIT and AaIT) was demonstrated at the molecular level. Although our study did not yield a product, it paves the way for future design of selective pesticides by capitalizing on the natural competence of scorpion toxins to distinguish between sodium channels of insects and vertebrates. We also show that future application of anti-insect toxins may enable to decrease the amounts of chemical pesticides due to their synergism.

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Gurevitz, Michael, William A. Catterall e Dalia Gordon. face of interaction of anti-insect selective toxins with receptor site-3 on voltage-gated sodium channels as a platform for design of novel selective insecticides. United States Department of Agriculture, dezembro de 2013. http://dx.doi.org/10.32747/2013.7699857.bard.

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Voltage-gated sodium channels (Navs) play a pivotal role in excitability and are a prime target of insecticides like pyrethroids. Yet, these insecticides are non-specific due to conservation of Navs in animals, raising risks to the environment and humans. Moreover, insecticide overuse leads to resistance buildup among insect pests, which increases misuse and risks. This sad reality demands novel, more selective, insect killers whose alternative use would avoid or reduce this pressure. As highly selective insect toxins exist in venomous animals, why not exploit this gift of nature and harness them in insect pest control? Many of these peptide toxins target Navs, and since their direct use via transformed crop plants or mediator microorganisms is problematic in public opinion, we focus on the elucidation of their receptor binding sites with the incentive of raising knowledge for design of toxin peptide mimetics. This approach is preferred nowadays by agro-industries in terms of future production expenses and public concern. However, characterization of a non-continuous epitope, that is the channel receptor binding site for such toxins, requires a suitable experimental system. We have established such a system within more than a decade and reached the stage where we employ a number of different insect-selective toxins for the identification of their receptor sites on Navs. Among these toxins we wish to focus on those that bind at receptor site-3 and inhibit Nav inactivation because: (1) We established efficient experimental systems for production and manipulation of site-3 toxins from scorpions and sea anemones. These peptides vary in size and structure but compete for site-3 on insect Navs. Moreover, these toxins exhibit synergism with pyrethroids and with other channel ligands; (2) We determined their bioactive surfaces towards insect and mammalian receptors (see list of publications); (3) We found that despite the similar mode of action on channel inactivation, the preference of the toxins for insect and mammalian channel subtypes varies greatly, which can direct us to structural features in the basis of selectivity; (4) We have identified by channel loop swapping and point mutagenesis extracellular segments of the Navinvolved with receptor site-3. On this basis and using channel scanning mutagenesis, neurotoxin binding, electrophysiological analyses, and structural data we offer: (i) To identify the residues that form receptor site-3 at insect and mammalian Navs; (ii) To identify by comparative analysis differences at site-3 that dictate selectivity toward various Navs; (iii) To exploit the known toxin structures and bioactive surfaces for modeling their docking at the insect and mammalian channel receptors. The results of this study will enable rational design of novel anti-insect peptide mimetics with minimized risks to human health and to the environment. We anticipate that the release of receptor site-3 molecular details would initiate a worldwide effort to design peptide mimetics for that site. This will establish new strategies in insect pest control using alternative insecticides and the combined use of compounds that interact allosterically leading to increased efficiency and reduced risks to humans or resistance buildup among insect pests.

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Gurevitz, Michael, William A. Catterall e Dalia Gordon. Learning from Nature How to Design Anti-insect Selective Pesticides - Clarification of the Interacting Face between Insecticidal Toxins and their Na-channel Receptors. United States Department of Agriculture, janeiro de 2010. http://dx.doi.org/10.32747/2010.7697101.bard.

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Structural details on the interacting faces of toxins and sodium channels (Navs), and particularly identification of elements that confer specificity for insects, are difficult to approach and require suitable experimental systems. Therefore, natural toxins capable of differential recognition of insect and mammalian Navs are valuable leads for design of selective compounds in insect control. We have characterized several scorpion toxins that vary in preference for insect and mammalian Navs, and identified residues important for their action. However, despite many efforts worldwide, only little is known about the receptor sites of these toxins, and particularly on differences between these sites on insect and mammalian Navs. Another problem arises from the massive overuse of chemical insecticides, which increases resistance buildup among various insect pests. A possible solution to this problem is to combine different insecticidal compounds, especially those that provide synergic effects. Our recent finding that combinations of insecticidal receptor site-3 toxins (sea anemone and scorpion alpha) with scorpion beta toxins or their truncated derivatives are synergic in toxicity to insects is therefore timely and strongly supports this approach. Our ability to produce toxins and various Navs in recombinant forms, enable thorough analysis and structural manipulations of both toxins and receptors. On this basis we propose to (1) restrict by mutagenesis the activity of insecticidal scorpion -toxins and sea anemone toxins to insects, and clarify the molecular basis of their synergic toxicity with antiinsect selective -toxins; (2) identify Nav elements that interact with scorpion alpha and sea anemone toxins and those that determine toxin selectivity to insects; (3) determine toxin-channel pairwise side-chain interactions by thermodynamic mutant cycle analysis using our large collection of mutant -toxins and Nav mutants identified in aim 2; (4) clarify the mode of interaction of truncated -toxins with insect Navs, and elucidate how they enhance the activity of insecticidal site-3 toxins. This research may lead to rational design of novel anti-insect peptidomimetics with minimal impact on human health and the environment, and will establish the grounds for a new strategy in insect pest control, whereby a combination of allosterically interacting compounds increase insecticidal action and reduce risks of resistance buildup.

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Banai, Menachem, e Gary Splitter. Molecular Characterization and Function of Brucella Immunodominant Proteins. United States Department of Agriculture, julho de 1993. http://dx.doi.org/10.32747/1993.7568100.bard.

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The BARD project was a continuation of a previous BARD funded research project. It was aimed at characterization of the 12kDa immunodominant protein and subsequently the cloning and expression of the gene in E. coli. Additional immunodominant proteins were sought among genomic B. abortus expression library clones using T-lymphocyte proliferation assay as a screening method. The 12kDa protein was identified as the L7/L12 ribosomal protein demonstrating in the first time the role a structural protein may play in the development of the host's immunity against the organism. The gene was cloned from B. abortus (USA) and B. melitensis (Israel) showing identity of the oligonucleotide sequence between the two species. Further subcloning allowed expression of the protein in E. coli. While the native protein was shown to have DTH antigenicity its recombinant analog lacked this activity. In contrast the two proteins elicited lymphocyte proliferation in experimental murine brucellosis. CD4+ cells of the Th1 subset predominantly responded to this protein demonstrating the development of protective immunity (g-IFN, and IL-2) in the host. Similar results were obtained with bovine Brucella primed lymphocytes. UvrA, GroE1 and GroEs were additional Brucella immunodominant proteins that demonstrated MHC class II antigenicity. The role cytotoxic cells are playing in the clearance of brucella cells was shown using knock out mice defective either in their CD4+ or CD8+ cells. CD4+ defective mice were able to clear brucella as fast as did normal mice. In contrast mice which were defective in their CD8+ cells could not clear the organisms effectively proving the importance of this subtype cell line in development of protective immunity. The understanding of the host's immune response and the expansion of the panel of Brucella immunodominant proteins opened new avenues in vaccine design. It is now feasible to selectively use immunodominant proteins either as subunit vaccine to fortify immunity of older animals or as diagnostic reagents for the serological survaillance.

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8

Altstein, Miriam, e Ronald Nachman. Rationally designed insect neuropeptide agonists and antagonists: application for the characterization of the pyrokinin/Pban mechanisms of action in insects. United States Department of Agriculture, outubro de 2006. http://dx.doi.org/10.32747/2006.7587235.bard.

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The general objective of this BARD project focused on rationally designed insect neuropeptide (NP) agonists and antagonists, their application for the characterization of the mechanisms of action of the pyrokinin/PBAN (PK-PBAN) family and the development of biostable, bioavailable versions that can provide the basis for development of novel, environmentally-friendly pest insect control agents. The specific objectives of the study, as originally proposed, were to: (i) Test stimulatory potencies of rationally designed backbone cyclic (BBC) peptides on pheromonotropic, melanotropic, myotropic and pupariation activities; (ii) Test the inhibitory potencies of the BBC compounds on the above activities evoked either by synthetic peptides (PBAN, LPK, myotropin and pheromonotropin) or by the natural endogenous mechanism; (iii) Determine the bioavailability of the most potent BBC compounds that will be found in (ii); (iv) Design, synthesize and examine novel PK/PBAN analogs with enhanced bioavailability and receptor binding; (v) Design and synthesize ‘magic bullet’ analogs and examine their ability to selectively kill cells expressing the PK/PBAN receptor. To achieve these goals the agonistic and antagonistic activities/properties of rationally designed linear and BBC neuropeptide (NP) were thoroughly studied and the information obtained was further used for the design and synthesis of improved compounds toward the design of an insecticide prototype. The study revealed important information on the structure activity relationship (SAR) of agonistic/antagonistic peptides, including definitive identification of the orientation of the Pro residue as trans for agonist activity in 4 PK/PBANbioassays (pheromonotropic, pupariation, melanotropic, & hindgut contractile) and a PK-related CAP₂b bioassay (diuretic); indications that led to the identification of a novel scaffold to develop biostbiostable, bioavailable peptidomimetic PK/PBANagonists/antagonists. The work led to the development of an arsenal of PK/PBAN antagonists with a variety of selectivity profiles; whether between different PKbioassays, or within the same bioassay between different natural elicitors. Examples include selective and non-selective BBC and novel amphiphilic PK pheromonotropic and melanotropic antagonists some of which are capable of penetrating the moth cuticle in efficacious quantities. One of the latter analog group demonstrated unprecedented versatility in its ability to antagonize a broad spectrum of pheromonotropic elicitors. A novel, transPro mimetic motif was proposed & used to develop a strong, selective PK agonist of the melanotropic bioassay in moths. The first antagonist (pure) of PK-related CAP₂b diuresis in flies was developed using a cisPro mimetic motif; an indication that while a transPro orientation is associated with receptor agonism, a cisPro orientation is linked with an antagonist interaction. A novel, biostablePK analog, incorporating β-amino acids at key peptidase-susceptible sites, exhibited in vivo pheromonotropic activity that by far exceeded that of PBAN when applied topically. Direct analysis of neural tissue by state-of-the-art MALDI-TOF/TOF mass spectrometry was used to identify specific PK/PK-related peptides native to eight arthropod pest species [house (M. domestica), stable (S. calcitrans), horn (H. irritans) & flesh (N. bullata) flies; Southern cattle fever tick (B. microplus), European tick (I. ricinus), yellow fever mosquito (A. aegypti), & Southern Green Stink Bug (N. viridula)]; including the unprecedented identification of mass-identical Leu/Ile residues and the first identification of NPs from a tick or the CNS of Hemiptera. Evidence was obtained for the selection of Neb-PK-2 as the primary pupariation factor of the flesh fly (N. bullata) among native PK/PK-related candidates. The peptidomic techniques were also used to map the location of PK/PK-related NP in the nervous system of the model fly D. melanogaster. Knowledge of specific PK sequences can aid in the future design of species specific (or non-specific) NP agonists/antagonists. In addition, the study led to the first cloning of a PK/PBAN receptor from insect larvae (S. littoralis), providing the basis for SAR analysis for the future design of 2ⁿᵈgeneration selective and/or nonselective agonists/antagonists. Development of a microplate ligand binding assay using the PK/PBAN pheromone gland receptor was also carried out. The assay will enable screening, including high throughput, of various libraries (chemical, molecular & natural product) for the discovery of receptor specific agonists/antagonists. In summary, the body of work achieves several key milestones and brings us significantly closer to the development of novel, environmentally friendly pest insect management agents based on insect PK/PBANNPs capable of disrupting critical NP-regulated functions.

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9

Lee, Richard, Moshe Bar-Joseph, K. S. Derrick, Aliza Vardi, Roland Brlansky, Yuval Eshdat e Charles Powell. Production of Antibodies to Citrus Tristeza Virus in Transgenic Citrus. United States Department of Agriculture, setembro de 1995. http://dx.doi.org/10.32747/1995.7613018.bard.

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Citrus tristeza virus (CTV) is the most important virus disease of citrus in the world. CTV causes death of trees on sour orange rootstock and/or stem pitting of scions regardless of rootstock which results in trees of low vigor, reduced yield with reduction in size and quality of fruit. The purpose of this project was to produce monoclonal antibodies (MABs) to CTV coat protein (CP), develop single domain antibodies (dAbs) or Fab fragments which neutralize the infection by binding to the virus, and to produce transformed plants which express the dAbs. The objectives of this research have been met and putative transgenic tobacco and citrus plants have been developed. These putative transgenic plants are presently undergoing evaluation to determine the level of dAbs expression and to determine their resistance to CTV. Additionally, the CTV genome has been sequenced and the CP gene of several biologically characterized CTV strains molecular characterized. This has indicated a correlation between CP sequence homology and biological activity, and the finding of DI RNAs associated with some CTV strains. Several MABs have been produced which enable broad spectrum identification of CTV strains while other MABs enable differentiation between mild and severe strains. The use of selected MAbs and determination of the CP gene sequence has enabled predictions of biological activities of unknown CTV isolates. The epitopes of two MABs, one reacting selectively with severe CTV strains and the other reacting with all strains, have been characterized at the molecular level.

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10

Kumar, Aishani, Thendral Yalini e Sunil Kumar C. Unlocking Cellular Control: The Promise of PROTACs in Disease Intervention. Science Reviews - Biology, maio de 2024. http://dx.doi.org/10.57098/scirevs.biology.3.2.1.

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The discovery of proteolysis-targeting chimeras (PROTACs) is among the most exciting and promising avenues in cancer therapy. These fascinating compounds signify a paradigm shift from traditional approaches to medication development, offering a new idea that leverages the complexities of biological mechanisms to accomplish highly focused degradation of particular proteins implicated in pathological processes. This novel strategy has the potential to address a number of drawbacks with conventional therapy techniques, such as the development of drug resistance and unexpected adverse effects resulting from interactions that are not intended. The fundamental attraction of PROTACs is their distinct mode of action, which is based on controlling the cell's own machinery for protein degradation. This orchestrated degradation translates to a substantial reduction in the levels of disease-driving proteins, often leading to the disruption of critical pathways involved in cancer growth and progression. The in-depth principles underlying PROTAC technology are thoroughly explored in this review study, which also provides insight into the complex chemical mechanisms that enable these chimeric molecules to specifically degrade certain proteins while leaving others intact. Showcasing the potential of PROTACs as a revolutionary force in targeted cancer therapy, and focusing on its application in prostate and breast cancer especially, the article draws from a comprehensive compilation of preclinical and clinical studies, advancements, and breakthroughs in the field. The methods used to create and refine PROTACs for various cancer types will be examined throughout the review, along with the subtleties of the ligand and linker choices that are crucial to their effectiveness and selectivity. The difficulties and possibilities of transferring this ground-breaking technology from the lab to clinical practice will also be thoroughly examined, with an emphasis on issues like bioavailability, administration strategies, and potential resistance mechanisms. Through the integration of perspectives from various studies, the objective is to present a thorough but succinct review of the state of ongoing PROTAC research, emphasizing both, noteworthy advancements and the important issues that still need to be resolved. In the end, our investigation into PROTACs aims to shed light on how they can change the face of cancer therapy by providing a preview of a day when targeted protein degradation of disease-causing proteins would lead the way in novel therapeutic approaches.

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