Academic literature on the topic 'Molecules - Environmental Interest'
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Journal articles on the topic "Molecules - Environmental Interest"
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Wojnárovits, László, and Erzsébet Takács. "Rate constants of dichloride radical anion reactions with molecules of environmental interest in aqueous solution: a review." Environmental Science and Pollution Research 28, no. 31 (June 4, 2021): 41552–75. http://dx.doi.org/10.1007/s11356-021-14453-w.
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AbstractNatural waters, water droplets in the air at coastal regions and wastewaters usually contain chloride ions (Cl-) in relatively high concentrations in the milimolar range. In the reactions of highly oxidizing radicals (e.g., •OH, •NO3, or SO4•-) in the nature or during wastewater treatment in advanced oxidation processes the chloride ions easily transform to chlorine containing radicals, such as Cl•, Cl2•-, and ClO•. This transformation basically affects the degradation of organic molecules. In this review about 400 rate constants of the dichloride radical anion (Cl2•-) with about 300 organic molecules is discussed together with the reaction mechanisms. The reactions with phenols, anilines, sulfur compounds (with sulfur atom in lower oxidation state), and molecules with conjugated electron systems are suggested to take place with electron transfer mechanism. The rate constant is high (107–109 M-1 s-1) when the reduction potential the one-electron oxidized species/molecule couple is well below that of the Cl2•-/2Cl- couple.
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Avramenko, Aleksandr G. "Chemical applications of hybridized light-matter states (a review)." Voprosy Khimii i Khimicheskoi Tekhnologii, no. 4 (July 2023): 3–16. http://dx.doi.org/10.32434/0321-4095-2023-149-4-3-16.
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Interactions between light and matter are a fundamental part of chemical sciences responsible for basic photophysical processes such as phosphorescence and fluorescence. However, these photophysical phenomena occur in the "weak" limit of interaction between light and matter in which the photon and molecule interact with each other without the former fundamentally changing the physical properties of the latter. By constructing a Fabry-Perot cavity, which traps light of a certain frequency, then placing a molecule in a cavity that undergoes a molecular electron transition at the frequency of the trapped light, scientists can force strong light-matter interaction. This interaction occurs if the exchange between the light of the cavity mode and the molecule's excited state is faster than the decay rate of either state, forming a hybrid light-matter state known as a polariton. The photophysical properties of these polariton states have been of interest to scientists due to the possibility that they can allow for the modification of the reactivity of molecules without the addition of functional groups or modification of the surrounding environment. Of particular interest is the ability of polaritons to influence the potential energy surface of molecules, with polaritons showing the ability to both, suppress the photochemical reaction in molecules such as spiropyran and stilbene, while also enhancing the nonradiative relaxation rate of porphyrins. Due to their photonic nature, polaritons have also shown the ability to facilitate long range energy transfer processes in organic dye molecules. This review focuses on discussing these recent advances in a chemistry context as well as the optical design of cavities required to sustain polaritons.
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Casey, William H. "Ligand- and oxygen-isotope-exchange pathways of geochemical interest." Environmental Chemistry 12, no. 1 (2015): 1. http://dx.doi.org/10.1071/en14043.
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Environmental context Most chemical processes in water are either ligand- or electron-exchange reactions. Here the general reactivity trends for ligand-exchange reactions in aqueous solutions are reviewed and it is shown that simple rules dominate the chemistry. These simple rules shed light on most molecular processes in water, including the uptake and degradation of pesticides, the sequestration of toxic metals and the corrosion of minerals. Abstract It is through ligand-exchange kinetics that environmental geochemists establish an understanding of molecular processes, particularly for insulating oxides where there are not explicit electron exchanges. The substitution of ligands for terminal functional groups is relatively insensitive to small changes in structure but are sensitive to bond strengths and acid–base chemistry. Ligand exchanges involving chelating organic molecules are separable into two classes: (i) ligand substitutions that are enhanced by the presence of the chelating ligand, called a ‘spectator’ ligand and (ii) chelation reactions themselves, which are controlled by the Lewis basicity of the attacking functional group and the rates of ring closure. In contrast to this relatively simple chemistry at terminal functional groups, substitutions at bridging oxygens are exquisitely sensitive to details of structure. Included in this class are oxygen-isotope exchange and mineral-dissolution reactions. In large nanometer-sized ions, metastable structures form as intermediates by detachment of a surface metal atom, often from a underlying, highly coordinated oxygen, such as μ4-oxo, by solvation forces. A metastable equilibrium is then established by concerted motion of many atoms in the structure. The newly undercoordinated metal in the intermediate adds a water or ligand from solution, and protons transfer to other oxygens in the metastable structure, giving rise to a characteristic broad amphoteric chemistry. These metastable structures have an appreciable lifetime and require charge separation, which is why counterions affect the rates. The number and character of these intermediate structures reflect the symmetry of the starting structure.
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Wojnárovits, László, Tünde Tóth, and Erzsébet Takács. "Rate constants of carbonate radical anion reactions with molecules of environmental interest in aqueous solution: A review." Science of The Total Environment 717 (May 2020): 137219. http://dx.doi.org/10.1016/j.scitotenv.2020.137219.
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Correale, Jorge, and Mauricio F. Farez. "The impact of environmental infections (parasites) on MS activity." Multiple Sclerosis Journal 17, no. 10 (October 2011): 1162–69. http://dx.doi.org/10.1177/1352458511418027.
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MS incidence has significantly increased during the second half of the 20th century, generating considerable interest in analyzing the basis for this rise in the developed world. Particular emphasis is being placed on the role infections might play in exacerbating or preventing disease onset. Epidemiological data suggest that improvement in sanitation conditions and reduced exposure to infection might explain, at least in part, these changes. The hygiene hypothesis is not new and is currently used to explain the increasing incidence of allergies and other autoimmune diseases. Because helminths are powerful modulators of host immunity, some authors hypothesize that reduced parasite exposure due to improved hygiene conditions may favor MS development. We discuss epidemiological, experimental, clinical and molecular data supporting the protective role of helminthes against MS. Better understanding of host–parasite interactions caused by specific parasite molecules with immunomodulatory effects will help combat allergies and autoimmune disease without the price of untoward infection as a side-effect.
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Nie, Nan, Xin Zhang, Chu Fang, Qiu Zhu, Jiao Lu, Fu Zhang, Qing Yao, Wei Huang, Xue Ding, and Li Xia. "Game Theory in Molecular Nanosensing System for Rapid Detection of Hg2+ in Aqueous Solutions." Applied Sciences 8, no. 12 (December 7, 2018): 2530. http://dx.doi.org/10.3390/app8122530.
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Game theory—the scientific study of interactive, rational decision making—describes the interaction of two or more players from macroscopic organisms to microscopic cellular and subcellular levels. Life based on molecules is the highest and most complex expression of molecular interactions. However, using simple molecules to expand game theory for molecular decision-making remains challenging. Herein, we demonstrate a proof-of-concept molecular game-theoretical system (molecular prisoner’s dilemma) that relies on formation of the thymine–Hg2+–thymine hairpin structure specifically induced by Hg2+ and fluorescence quenching and molecular adsorption capacities of cobalt oxyhydroxide (CoOOH) nanosheets, resulting in fluorescence intensity and distribution change of polythymine oligonucleotide 33-repeat thymines (T33). The “bait” molecule, T33, interacted with two molecular players, CoOOH and Hg2+, in different states (absence = silence and presence = betrayal), regarded as strategies. We created conflicts (sharing or self-interest) of fluorescence distribution of T33, quantifiable in a 2 × 2 payoff matrix. In addition, the molecular game-theoretical-system based on T33 and CoOOH was used for sensing Hg2+ over the range of 20 to 600 nM with the detection limit of 7.94 nM (3σ) and for determination of Hg2+ in pond water. Inspired by the proof-of-concept for molecular game theory, various molecular decision-making systems could be developed, which would help promote molecular information processing and generating novel molecular intelligent decision systems for environmental monitoring and molecular diagnosis and therapy.
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SHANKARAN, D., K. GOBI, and N. MIURA. "Recent advancements in surface plasmon resonance immunosensors for detection of small molecules of biomedical, food and environmental interest." Sensors and Actuators B: Chemical 121, no. 1 (January 30, 2007): 158–77. http://dx.doi.org/10.1016/j.snb.2006.09.014.
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Minati, L., G. Speranza, I. Bernagozzi, S. Torrengo, L. Toniutti, B. Rossi, M. Ferrari, and A. Chiasera. "Synthesis of Carbon Nanotubes/Gold Nanoparticles Hybrids for Environmental Applications." Advances in Science and Technology 71 (October 2010): 34–39. http://dx.doi.org/10.4028/www.scientific.net/ast.71.34.
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Multi-walled carbon nanotubes were chemically cut by acid treatments and then deposited on 2-aminoethanethiol-modified gold substrate by the application of an external electric field. 2-aminoethanethiol-capped gold nanoparticles were then covalently bonded to the nanotubes to exploit their plasmon resonances. Reaction intermediates as well as the final products were analyzed by X-Ray Photoelectron Spectroscopy, Atomic Force Microscopy and Scanning Electron Microscopy. The synergetic interaction between carbon nanotubes and gold nanoparticles leads to an efficient signal enhancement in Raman spectra. This is of particular interest for the detection of toxic molecules dangerous for the environment.
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Bacon, Stuart L., Andrew J. Daugulis, and J. Scott Parent. "Isobutylene-rich imidazolium ionomers for use in two-phase partitioning bioreactors." Green Chemistry 18, no. 24 (2016): 6586–95. http://dx.doi.org/10.1039/c6gc02251k.
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Imidazolium ionomer derivatives of an isobutylene-rich elastomer demonstrated superior absorption characteristics for target molecules of biological interest compared to their non-ionic parent material, while retaining biocompatibility with a range of suspended cell cultures.
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Zhou, Qingqing, Zhigang Xu, and Zhimin Liu. "Molecularly Imprinting–Aptamer Techniques and Their Applications in Molecular Recognition." Biosensors 12, no. 8 (July 29, 2022): 576. http://dx.doi.org/10.3390/bios12080576.
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Molecular imprinting–aptamer techniques exhibit the advantages of molecular imprinting and aptamer technology. Hybrids of molecularly imprinted polymer–aptamer (MIP–aptamer) prepared by this technique have higher stability, binding affinity and superior selectivity than conventional molecularly imprinted polymers or aptamers. In recent years, molecular imprinting–aptamer technologies have attracted considerable interest for the selective recognition of target molecules in complex sample matrices and have been used in molecular recognition such as antibiotics, proteins, viruses and pesticides. This review introduced the development of molecular imprinting–aptamer-combining technologies and summarized the mechanism of MIP–aptamer formation. Meanwhile, we discussed the challenges in preparing MIP–aptamer. Finally, we summarized the application of MIP–aptamer to the molecular recognition in disease diagnosis, environmental analysis, food safety and other fields.
Dissertations / Theses on the topic "Molecules - Environmental Interest"
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Roucou, Anthony. "Spectroscopie haute résolution de spectres rotationnellement denses dédiée à la détection en phase gazeuse de molécules d'intérêt environnemental et défense." Thesis, Littoral, 2018. http://www.theses.fr/2018DUNK0482/document.
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Ces dernières décennies, la spectroscopie moléculaire a bénéficié du progrès des spectromètres, notamment en terme de sélectivité et sensibilité, et de méthodes d'analyse et de calculs de chimie quantique toujours plus avancés. Désormais, la spectroscopie rotationnelle s'oriente vers l'analyse de systèmes moléculaires plus complexes caractérisés spectralement par une forte densité de raies. La congestion spectrale des espèces étudiées dans ma thèse s'explique non seulement par de faibles constantes rotationnelles mais aussi par la présence d'états vibrationnels excités à température ambiante, une forte richesse isotopique, un haut degré de splittings dus aux mouvements de grande amplitude ou encore par un paysage conformationnel complexe. Cette thèse illustre ainsi divers scénarii à travers les études du chlorure de thionyle, des nitrotoluènes et des méthoxyphénols. Les spectres rovibrationnels des bandes v2 et v5 des isotopologues du chlorure de thionyle ont été mesurés dans l'infrarouge lointain au synchroton SOLEIL et analysés en utilisant une approche semi-automatique basée sur des algorithmes évolutionnaires. Les isomères du nitrotoluène ont été ciblés pour leur intérêt défense comme traceurs d'explosif (TNT), les spectres de rotation pure ont été mesurés dans les régions micro-ondes en jet moléculaire et millimétrique à température ambiante. Le spectre millimétrique du 3-nitrotoluène était particulièrement faible et congestionné avec des splittings dus à la rotation interne très importants (jusqu'à plusieurs GHz) en raison d'une barrière de rotation très faible ( Vз=6.7659(24)cmˉ ¹). La limite de détection a été estimée et une liste de raies établie. Les spectres millimétriques des 2-nitrotoluène et 4-nitrotoluène ont également été partiellement analysés. Enfin, les méthoxyphénols émis lors de feux de biomasse ont également étudiés comme précurseurs d'aérosols organiques secondaires pour leur détection atmosphérique future. Associée à des calculs de chimie quantique, l'analyse du spectre millimétrique du 3-méthoxyphénol mesuré à température ambiante dans la région millimétrique a permis de déterminer la stabilité relative de quatre conformèresIn recent decades, molecular spectroscopy has benefited from the progress of spectrometers, particularly in terms of selectivity and sensitivity, and from the continuous advancement of the analysis methods and quantum chemistry calculations. Today, rational spectroscopy is moving towards the analysis of more complex molecular systems spectrally characterized by a high density of lines. The spectral congestion of the species studied in this thesis is not only explained by low rotational constants, but also by the presence of vibrational states excited at room temperature, a high isotopic richness, a high degree of line splitting due to large amplitude motions or by a complex conformational landscape. This thesis thus illustrates various scenarios through the studies of thionyl chloride, nitrotoluenes and methoxyphenols. The rovibrational spectra of the v2 and v5 bands of the isotopologues of thionyl chloride were measured in far-infrared at the SOLEIL synchroton and analyzed using a semi-automatic approach based on evolutionary algorithms. The isomers of nitrotoluene have been targeted for military application as explosive taggants (TNT), the pure rotation spectra were measured in the microwave region in molecular jet and in the millimeter-wave region at room temperature. The millimeter-wave spectrum of 3-nitrotoluene was especially weak and congested with very large internal rotation splittings (up to several GHz) due to a very weak rotational barrier (V3=6.7659(24)cmˉ ¹). The detection limit was estimated and a linelist established. The 2-nitrotoluene and 4-nitrotoluene millimeter-wave spectra have been also partially analyzed. Finally, methoxyphenols emitted during biomass fires have also been studied as they are secondary organic aerosol precursors for their future atmospheric detection. Combined with quantum chemistry calculations, the analysis of the millimeter-wave spectrum of the 3-methoxyphenol measured at room temperature permitted the relative stability of four conformers to be determined
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Santos, Figueroa Luis Enrique. "New approaches for the development of chromo-fluorogenic sensors for chemical species of biological, industrial and environmental interest." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/43216.
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El presente proyecto de investigación está enfocado al desarrollo de sensores químicos fluoro-cromogénicos, para la detección y determinación de especies químicas de interés biológico, industrial y medioambiental de forma selectiva y con alta sensibilidad.
En forma general, se busca el diseñar nuevos sistemas sensores basados en compuestos (receptores) formados por dos unidades: una unidad coordinante que interacciona con el anión a determinar y una unidad generadora de señal que alerta del reconocimiento molecular efectuado.
Durante este estudio se están preparando diversas moléculas receptoras funcionalizandas con grupos modificadores de estructura para evaluar su influencia sobre las capacidades de detección y selectividad como receptores de especies específicas en diferentes condiciones y medios.
Las diferentes aproximaciones en prueba implican a su vez el diseño y síntesis molecular, así como el análisis de las diferentes señales ópticas producidas en el reconocimiento, con el fin de diseñar sistemas de alta eficacia y eficiencia, y con posibilidades reales de aplicación.Santos Figueroa, LE. (2014). New approaches for the development of chromo-fluorogenic sensors for chemical species of biological, industrial and environmental interest [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/43216
TESIS
Premiado
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McIlwrick, Silja [Verfasser], and Chadi [Akademischer Betreuer] Touma. "Genetic risk factors and early-life stress interact to shape endophenotypes of affective disorders : behavioral, neuroendocrine, and molecular consequences of a gene × environment interaction / Silja McIlwrick ; Betreuer: Chadi Touma." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1132061105/34.
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Chiu, Jia-jyun, and 邱家軍. "How Does the Wasp Venom Mastoparan-B Interact with Membrane Mimicing Environment: An Aspect from Molecular Dynamics Simulation." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/72863670818971215174.
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碩士國立成功大學
工程科學系碩博士班
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In Taiwan, the black-bellied hornet (Vespa basalis) is certainly the most dangerous and aggressive one in all species of vespine wasp. It has been found that its venom possesses important medicinal values by diversely researches. Mastoparan B (MP-B) is the major component of venom of Vespa basalis, which has shown various functions, such as activation of phospholipase A2 and C, erythrocyte lysis, histamine release, and activation of G-proteins. MP-B is a kind of cationic tetradecapeptide, which can form amphiphilic α-helix with hydrophilic residues on one side and hydrophobic ones on the other side. According to former researches, MP-Bs are random coil in aqueous solution and adopt α-helix conformation in the presence of trifluoroethanol (TFE). Notwithstanding so many research works about the relationship of structure-function of MP-B, mainly about the conformation of MP-B's binding to membrane, the detailed dynamical informations of MP-B in membrane-like environment and interactions of MP-B with membrane are still poor. Therefore, I tried to simulate MP-B in TFE/water mixtures by molecular dynamics to insight into the mechanism of membrane-perturbation of MP-B. My 30ns simulation have shown that the unstability of MP-B in high concentration of TFE/water mixtures may be a critical factor in the interaction of MP-B with membrane.
Books on the topic "Molecules - Environmental Interest"
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Ryabov, Vladimir. Oil and Gas Chemistry. ru: INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1017513.
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The textbook provides up-to-date data on the composition and properties of hydrocarbons and other oil and gas compounds, on the physical and chemical methods and methods for separating and identifying oil components (molecular spectroscopy, mass spectrometry, NMR spectroscopy, electron paramagnetic resonance, atomic adsorption spectroscopy, neutron activation analysis). The chemistry and mechanism of thermal and catalytic transformations of oil components in the main processes of oil raw materials processing, as well as the problems of the origin of oil and the transformation of oil in the environment are considered.
Meets the requirements of the federal state educational standards of higher education of the latest generation.
It is intended for training in the course "Chemistry of oil and gas", for the preparation of bachelors, masters and certified specialists in the field of training "Oil and Gas business". It can be used for training in other areas in oil and gas universities and be of interest to specialists working in the field of chemistry and technology of oil refining and in other areas of the oil and gas industry.
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Karnwal, Arun, and Abdel Rahman Mohammad Said Al-Tawaha, eds. Environmental Microbiology: Advanced Research and Multidisciplinary Applications. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/97816810895841220101.
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Environmental Microbiology: Advanced Research and Multidisciplinary Applications focus on the current research on microorganisms in the environment. Contributions in the volume cover several aspects of applied microbial research, basic research on microbial ecology and molecular genetics. The reader will find a collection of topics with theoretical and practical value, allowing them to connect environmental microbiology to a variety of subjects in life sciences, ecology, and environmental science topics. Advanced topics including biogeochemical cycling, microbial biosensors, bioremediation, application of microbial biofilms in bioremediation, application of microbial surfactants, microbes for mining and metallurgical operations, valorization of waste, and biodegradation of aromatic waste, microbial communication, nutrient cycling and biotransformation are also covered. The content is designed for advanced undergraduate students, graduate students, and environmental professionals, with a comprehensive and up-to-date discussion of environmental microbiology as a discipline that has greatly expanded in scope and interest over the past several decades.
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Beaver, Kevin M., Eric J. Connolly, Joseph L. Nedelec, and Joseph A. Schwartz. On the Genetic and Genomic Basis of Aggression, Violence, and Antisocial Behavior. Edited by Rosemary L. Hopcroft. Oxford University Press, 2018. http://dx.doi.org/10.1093/oxfordhb/9780190299323.013.15.
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There is a great deal of interest in examining the genetic and environmental architecture to aggression, violence, and antisocial behaviors. This interest has resulted in hundreds of studies being published that estimate genetic and environmental effects on antisocial phenotypes. The results generated from these studies have been remarkably consistent and have contributed greatly to the knowledge base on the etiology of antisocial behavior. This chapter reviews the research on the genetic basis to antisocial phenotypes by presenting the results related to the heritability of antisocial phenotypes. It also discusses some of the molecular genetic association studies as well as genome-wide association studies that focus on the development of antisocial behaviors. In doing so, it also reviews findings related to gene–environment interactions. The chapter concludes by discussing some of the ways in which these findings could be used for intervention and prevention programs.
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Jay, Taylor R., Shane M. Bemiller, Lee E. Neilson, Paul J. Cheng-Hathaway, and Bruce T. Lamb. Neuroinflammation and Neurodegenerative Diseases. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780190233563.003.0004.
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Neuroinflammation has long been associated with many neurodegenerative diseases (NDDs). Immune-related genetic and environmental risk factors have recently been identified for NDDs, suggesting that neuroinflammation can play an active role in modifying NDD pathologies. Immune cells that underlie this neuroinflammatory response can have both beneficial and detrimental roles in NDDs. These cells can engage in clearance of debris and provide important survival factors to neighboring neurons. However, these cells can also release inflammatory molecules that promote oxidative stress and excitotoxic damage in surrounding neurons, and aberrantly clear healthy cells and structures from the brain. In turn, the cells within the brain play important roles in determining the phenotype and function of these immune cells, and changes in the interaction among these cells in the context of disease can lead to detrimental immune cell activation. There has been recent interest in developing inflammation-related biomarkers to help diagnose NDDs and immune-targeted therapeutics.
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Mareeswaran, Paulpandian Muthu, Palaniswamy Suresh, and Seenivasan Rajagopal, eds. Photophysics of Supramolecular Architectures. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/97898150491901220101.
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This reference provides collective information about the physical and photophysical changes of supramolecules after encapsulation. It covers luminescent systems involving a range of host molecules such as calixarenes, cyclodextrin, resorcinanene-crowns, pillararenes, cucurbituril, and metallacycles. Chapters also discuss the effect of the macrocyclic environment on the properties of functionalized molecules, including the variations in folding and unfolding patterns. Each chapter is supplemented with detailed references, making this an ideal resource for scholars interested in supramolecular photophysics.
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Jones, Christopher R. Neurobiology of Circadian Rhythms Disorders. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199937837.003.0175.
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Temporal organization of nervous system function includes daily rhythms driven by a molecular-genetic hypothalamic “clock” with an intrinsic period length of approximately (circa) one day (diem). The resulting circadian rhythm influences all aspects of brain function and internally synchronizes the circadian oscillations inherent in all other body tissues. Idiosyncratic circadian characteristics interact with perceived environmental stimuli to determine each individual’s entrainment pattern of external synchronization with the day-night cycle. Idiosyncratic entrainment patterns that may come to medical attention include delayed, free-running, advanced, or absent sleep rhythms. Prolonged jet travel and shift work are difficult entrainment challenges for most people.
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West-Eberhard, Mary Jane. Developmental Plasticity and Evolution. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195122343.001.0001.
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The first comprehensive synthesis on development and evolution: it applies to all aspects of development, at all levels of organization and in all organisms, taking advantage of modern findings on behavior, genetics, endocrinology, molecular biology, evolutionary theory and phylogenetics to show the connections between developmental mechanisms and evolutionary change. This book solves key problems that have impeded a definitive synthesis in the past. It uses new concepts and specific examples to show how to relate environmentally sensitive development to the genetic theory of adaptive evolution and to explain major patterns of change. In this book development includes not only embryology and the ontogeny of morphology, sometimes portrayed inadequately as governed by "regulatory genes," but also behavioral development and physiological adaptation, where plasticity is mediated by genetically complex mechanisms like hormones and learning. The book shows how the universal qualities of phenotypes--modular organization and plasticity--facilitate both integration and change. Here you will learn why it is wrong to describe organisms as genetically programmed; why environmental induction is likely to be more important in evolution than random mutation; and why it is crucial to consider both selection and developmental mechanism in explanations of adaptive evolution. This book satisfies the need for a truly general book on development, plasticity and evolution that applies to living organisms in all of their life stages and environments. Using an immense compendium of examples on many kinds of organisms, from viruses and bacteria to higher plants and animals, it shows how the phenotype is reorganized during evolution to produce novelties, and how alternative phenotypes occupy a pivotal role as a phase of evolution that fosters diversification and speeds change. The arguments of this book call for a new view of the major themes of evolutionary biology, as shown in chapters on gradualism, homology, environmental induction, speciation, radiation, macroevolution, punctuation, and the maintenance of sex. No other treatment of development and evolution since Darwin's offers such a comprehensive and critical discussion of the relevant issues. Developmental Plasticity and Evolution is designed for biologists interested in the development and evolution of behavior, life-history patterns, ecology, physiology, morphology and speciation. It will also appeal to evolutionary paleontologists, anthropologists, psychologists, and teachers of general biology.
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Dalbeth, Nicola. Clinical features of gout. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198748311.003.0005.
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About 60% of the variance in serum urate levels can be explained by inherited genetic factors, but the extent of the contribution of genetic factors to gout in the presence of hyperuricaemia is not known. Genome-wide association studies in Europeans have identified 28 loci controlling serum urate levels, although the molecular basis of the majority of these genetic associations is currently unknown. The SLC2A9 and ABCG2 renal and gut uric acid transporters have very strong effects on urate levels and the risk of gout. Other uric acid transporters (e.g. SLC22A11/OAT478, SLC22A12/URAT1) and a glycolysis gene (GCKR) are associated with urate levels. Environmental exposures such as sugar-sweetened beverages and alcohol interact with urate-associated genetic variants in an unpredictable fashion. Very little is known about the genetic control of gout in the presence of hyperuricaemia, formation of monosodium urate crystals, and the immune response.
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Connington, J. J. Nordenholt's Million. The MIT Press, 2022. http://dx.doi.org/10.7551/mitpress/14276.001.0001.
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As a bacteria threatens to wipe out humankind, a plutocrat sets himself up as the benignant dictator of a survivalist colony. In this novel originally published in 1923, as denitrifying bacteria inimical to plant growth spreads around the world, toppling civilizations and threatening to wipe out humankind, the British plutocrat Nordenholt sets himself up as the benignant dictator of a ruthlessly efficient, entirely undemocratic, survivalist colony established in Scotland's Clyde Valley. Discovering just how far their employer is willing to go in his effort to spare one million lives, Jack Flint, the colony's director of operations, and Elsa Huntingtower, Nordenholt's personal assistant, are forced to grapple with the question of whether a noble end justifies dastardly means. Matthew Battles is the author of Library: An Unquiet History, Palimpsest, and Tree, as well as the story collection The Sovereignties of Invention. His writing on the cultural dimensions of science, technology, and the natural world have appeared in the Atlantic, the Boston Globe, and Orion. For Harvard''s metaLAB, he develops research into the dark abundance of collections, cultural and technology, and conditions of experience in the context of deep time. Evan Hepler-Smith teaches the history of science and technology and environmental history at Duke University. He has a special interest in the history of chemicals and chemistry, information technology, and environmental regulation. His book in progress is entitled Compound Words: Chemical Information and the Molecular World. His writing has been published in the New York Times, the Wall Street Journal, Time.com, and Public Books.
Book chapters on the topic "Molecules - Environmental Interest"
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Snow, Jonathan. "What Does Cell Biology Have to Do with Saving Pollinators?" In Transforming Education for Sustainability, 129–46. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-13536-1_8.
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AbstractAs a cell and molecular biologist trained in biomedical sciences, my early research focused on human disease etiology. I was fortunate to be able to realign my research and personal interests in sustainability when I began working on honey bee health as I transitioned to faculty positions at liberal arts colleges. As an Associate Professor of Biology at Barnard College, my teaching focuses on biology at the cell and molecular level, which is strongly associated with problems of human health. A major challenge I have faced centers around connecting the techniques and ways of thinking used in the study of cell biology with the broader environmental issues of honey bee disease and the growing pollinator crisis. In this chapter, I describe how I have worked to incorporate sustainability in a broad sense and justice in a somewhat narrow ecological sense into my lab and my teaching, with a specific focus on my course, Laboratory in Cell Biology. The lab class structure pursued here, which shares many aspects with the course-based undergraduate research experiences (CURE) model, seeks to create an authentic and inclusive environment to increase laboratory science involvement and enthusiasm in students from diverse backgrounds.
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Pantchev, Ivelin, Goritsa Rakleova, and Atanas Atanassov. "The stability of dsRNA during external applications - an overview." In RNAi for plant improvement and protection, 94–101. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789248890.0010.
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Abstract The research community is deeply convinced that RNA is unstable in the environment. Its roots rise from numerous failed attempts to isolate functional cellular RNA molecules. Further support had originated from the fast turnover of RNA in the cells. The situation changed recently with the discovery that externally applied dsRNA can produce targeted gene silencing in plant-feeding insects. First results have demonstrated that external dsRNA can successfully pass the insect gastrointestinal tract and reach its final destination within the body cells. This was somewhat unexpected and sparked new interest in RNA stability in the environment and its fate in the insect organism. In this brief review we make an attempt to summarize current knowledge and to propose a model of how dsRNA can perform its function under these settings.
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Pantchev, Ivelin, Goritsa Rakleova, and Atanas Atanassov. "The stability of dsRNA during external applications - an overview." In RNAi for plant improvement and protection, 94–101. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789248890.0094.
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Abstract The research community is deeply convinced that RNA is unstable in the environment. Its roots rise from numerous failed attempts to isolate functional cellular RNA molecules. Further support had originated from the fast turnover of RNA in the cells. The situation changed recently with the discovery that externally applied dsRNA can produce targeted gene silencing in plant-feeding insects. First results have demonstrated that external dsRNA can successfully pass the insect gastrointestinal tract and reach its final destination within the body cells. This was somewhat unexpected and sparked new interest in RNA stability in the environment and its fate in the insect organism. In this brief review we make an attempt to summarize current knowledge and to propose a model of how dsRNA can perform its function under these settings.
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Moreira, Sofia, Jaime A. Espina, Joana E. Saraiva, and Elias H. Barriga. "A Toolbox to Study Tissue Mechanics In Vivo and Ex Vivo." In Methods in Molecular Biology, 495–515. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2035-9_29.
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AbstractDuring vertebrate embryogenesis, tissues interact and influence each other’s development to shape an embryo. While communication by molecular components has been extensively explored, the role of mechanical interaction between tissues during embryogenesis is just starting to be revealed. Addressing mechanical involvement in morphogenesis has traditionally been challenging mainly due to the lack of proper tools to measure and modify mechanical environments of cells in vivo. We have recently used atomic force microscopy (AFM) to show that the migration of the Xenopus laevis cephalic neural crest cells is triggered by stiffening of the mesoderm, a tissue that neural crest cells use as a migratory substrate in vivo. Interestingly we showed that the activity of the planar cell polarity (PCP) pathway is required to mediate this novel mechanical interaction between two tissues. In this chapter, we share the toolbox that we developed to study the role of PCP signaling in mesoderm cell accumulation and stiffening (in vivo) as well as the impact of mesoderm stiffness in promoting neural crest cell polarity and migration (ex vivo). We believe that these tools can be of general use for investigators interested in addressing the role of mechanical inputs in vivo and ex vivo.
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Kontogiannatos, Dimitrios, Anna Kolliopoulou, and Luc Swevers. "The 'Trojan horse' approach for successful RNA interference in insects." In RNAi for plant improvement and protection, 25–39. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789248890.0004a.
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Abstract Since the discovery of RNA interference in 1998 as a potent molecular tool for the selective downregulation of gene expression in almost all eukaryotes, increasing research is being performed in order to discover applications that are useful for the pharmaceutical and chemical industry. The ease of use of double-stranded RNA for targeted in vivo gene silencing in animal cells and tissues gave birth to a massive interest from industry in order to discover biotechnological applications for human health and plant protection. For insects, RNAi became the 'Holy Grail' of pesticide manufacturing, because this technology is a promising species-specific environmentally friendly approach to killing natural enemies of cultured plants and farmed animals. The general idea to use RNAi as a pest-control agent originated with the realization that dsRNAs that target developmentally or physiologically important insect genes can cause lethal phenotypes as a result of the specific gene downregulation. Most importantly to achieve this, dsRNA is not required to be constitutively expressed via a transgene in the targeted insect but it can be administrated orally after direct spraying on the infested plants. Similarly, dsRNAs can be administered to pests after constitutive expression as a hairpin in plants or bacteria via stable transgenesis. Ideally, this technology could have already been applied in integrated pest management (IPM) if improvements were not essential in order to achieve higher insecticidal effects. There are many limitations that decrease RNAi efficiency in insects, which arise from the biochemical nature of the insect gut as well as from deficiencies in the RNAi core machinery, a common phenomenon mostly observed in lepidopteran species. To overcome these obstacles, new technologies should be assessed to ascertain that the dsRNA will be transferred intact, stable and in high amounts to the targeted insect cells. In this chapter we will review a wide range of recent discoveries that address the delivery issues of dsRNAs in insect cells, with a focus on the most prominent and efficient technologies. We will also review the upcoming and novel use of viral molecular components for the successful and efficient delivery of dsRNA to the insect cell.
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Kontogiannatos, Dimitrios, Anna Kolliopoulou, and Luc Swevers. "The 'Trojan horse' approach for successful RNA interference in insects." In RNAi for plant improvement and protection, 25–39. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789248890.0025.
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Abstract Since the discovery of RNA interference in 1998 as a potent molecular tool for the selective downregulation of gene expression in almost all eukaryotes, increasing research is being performed in order to discover applications that are useful for the pharmaceutical and chemical industry. The ease of use of double-stranded RNA for targeted in vivo gene silencing in animal cells and tissues gave birth to a massive interest from industry in order to discover biotechnological applications for human health and plant protection. For insects, RNAi became the 'Holy Grail' of pesticide manufacturing, because this technology is a promising species-specific environmentally friendly approach to killing natural enemies of cultured plants and farmed animals. The general idea to use RNAi as a pest-control agent originated with the realization that dsRNAs that target developmentally or physiologically important insect genes can cause lethal phenotypes as a result of the specific gene downregulation. Most importantly to achieve this, dsRNA is not required to be constitutively expressed via a transgene in the targeted insect but it can be administrated orally after direct spraying on the infested plants. Similarly, dsRNAs can be administered to pests after constitutive expression as a hairpin in plants or bacteria via stable transgenesis. Ideally, this technology could have already been applied in integrated pest management (IPM) if improvements were not essential in order to achieve higher insecticidal effects. There are many limitations that decrease RNAi efficiency in insects, which arise from the biochemical nature of the insect gut as well as from deficiencies in the RNAi core machinery, a common phenomenon mostly observed in lepidopteran species. To overcome these obstacles, new technologies should be assessed to ascertain that the dsRNA will be transferred intact, stable and in high amounts to the targeted insect cells. In this chapter we will review a wide range of recent discoveries that address the delivery issues of dsRNAs in insect cells, with a focus on the most prominent and efficient technologies. We will also review the upcoming and novel use of viral molecular components for the successful and efficient delivery of dsRNA to the insect cell.
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Palchetti, Ilaria, and Marco Mascini. "Biosensor Techniques for Environmental Monitoring." In Nucleic Acid Biosensors for Environmental Pollution Monitoring, 1–16. The Royal Society of Chemistry, 2011. http://dx.doi.org/10.1039/bk9781849731317-00001.
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Biosensors are considered to be devices of interest for environmental monitoring. The peculiar characteristics of biosensors allow them to complement current field screening and monitoring methods, especially when continuous, real-time, in situ monitoring is required. However, biosensors still face problems of stability, detection sensitivity, and reliability of the biomolecular recognition element. In recent years, new binding molecules have been introduced in many areas of science. In this chapter, the different natural or synthetic molecules employed in the development of biosensors for environmental monitoring are reviewed, with special emphasis on innovative (bio)receptors claimed to overcome stability concerns of traditional sensing elements. The key role of nucleic acids in the identification of new smart bioreceptors is described.
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Alia, Telli. "Biosurfactants for Biodégradation." In Bioremediation for Environmental Pollutants, 118–36. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815123494123010007.
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The low toxicity, biodegradability, powerful surface activity, and the functionality under extreme conditions (pH, salinity and temperature) make the surfactants produced by micro-organisms (bacteria, fungi, and yeasts) best surface active molecules that can replace hazardous and non degradable chemical surfactants in different industries and fields. In recent decades, there has been growing interest in the use of biosurfactants for bioremediation of environmental pollution and biodegradation of various categories of hydrophobic pollutants and waste due to their eco-friendly and low-cost properties. This chapter presents the classification, the characteristics, and the potential uses of biosurfactants in the solubilization and enhancing the biodegradation of low solubility compounds.<br>
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Mohammed, Mohammed, and Rozyanty Rahman. "Utilizing Photocatalysts in Reducing Moisture Absorption in Composites of Natural Fibers." In Photocatalysts - New Perspectives [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106543.
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Due to growing environmental consciousness and the depletion of oil supplies, numerous efforts have been made to replace synthetic fibers in fiber-reinforced composites with natural fibers (NFr). The low cost and abundance of NFr and its biodegradability and low density have encouraged researchers worldwide to study their potential applications in several industrial sectors. However, NFr has several disadvantages: excessive moisture absorption and subsequent swelling and degradation, low chemical and fire resistance, and insufficient interfacial interactions with polymers. Consequently, there is great interest in modifying the surface of NFr using a variety of methods. This chapter presents an overview of the NFr, its characterization, the problems associated with adding NFr to polymer composites. This literature survey suggests an in-depth review of photocatalysis by utilizing photocatalysts nanoparticle (PHNPs) aimed at increasing the hydrophobicity and interfacial bonding between the NFr and the matrix Using a photo-induced oxidation mechanism to disassemble water molecules, pollutants, and bacteria in a wet environment. Additionally, we reviewed the effects of these PHNPs on the moisture absorption, mechanical characteristics, and dimensional stability of NFr composites. As a result, this review article may make a valuable contribution to researchers interested in coating and treating NFr to further enhance their surface characteristics.
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Rahman, Aminur, and Abu Bin Imran. "Stimuli-responsive and Self-healing Multicomponent Hydrogels for Biomedical Applications." In Multicomponent Hydrogels, 578–603. The Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/bk9781837670055-00578.
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Hydrogels can absorb and retain large quantities of water or other molecules inside their pores without dissolving in any solvents. Multicomponent stimuli-responsive hydrogels are especially interesting because they can change their physical and chemical properties with surrounding environmental stimuli. Multicomponent hydrogels with self-healing properties are attractive because of their capacity to repair and restore function after the damage has occurred. Researchers in drug delivery, gene regulation, tissue engineering, 3D printing, soft robotics, and other biomedical fields have shown keen interest in stimulus-responsive and self-healing multicomponent hydrogels. This chapter will address various multicomponent stimuli-responsive and self-healing hydrogels and their action mechanisms. A brief description of pertinent examples and their biomedical applications will also be provided.
Conference papers on the topic "Molecules - Environmental Interest"
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Sauer, M., K. H. Drexhage, K. T. Han, S. Nord, and C. Zander. "Following the Dynamics of Single Oligonucleotide Molecules in Water." In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/lacea.1998.lmc.14.
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The dynamic fluorescence characteristics of individual dye molecules in specific local environment are of particular interest for many biological applications.1,2 Furthermore, dye molecules that are influenced by the environment can act as molecular probes, i. e. they exhibit information about neighbouring groups and changes in the microenvironment. They also allow the direct observation of individual dynamic events such as conformational changes of a biological macromolecule if they are monitored on the single-molecule level. In addition, measurements on individual molecules are well suited for the study of complex systems in which it is not known whether all molecules exhibit the same characteristics or each molecule contributes with its individual characteristics to the observed behaviour.
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Barnes, M. D., W. B. Whitten, J. M. Ramsey, and S. Arnold. "Photophysics of Surfactant Molecules in Microdroplets." In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/lacea.1996.lwb.6.
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Over the last several years, the study of fluorescence properties in both time and frequency domain of atoms in micron-sized optical cavities has held considerable interest in the physics and quantum optics communities. In addition to fascinating purely scientific aspects of the phenomenon of cavity quantum electrodynamics (QED), the ability to modify molecular fluorescence properties in a microcavity offers potentially significant sensitivity advantages for ultrasensitive - or, single molecule - fluorescence detection. For example, two important quantities which limit sensitivity in single molecule fluorescence detection - the saturated absorption rate and the integrated fluorescence yield - can be significantly increased by enhancing the fluorescence decay rate. We have shown previously that fluorescence decay rates1 as well as the integrated fluorescence yield2 of rhodamine 6G can be significantly enhanced in glycerol microdroplets. However, exploitation of these effects in order to gain sensitivity in single molecule fluorescence detection is nontrivial for at least two important reasons. First, the magnitude of decay rate enhancement depends on the position of the molecule within the droplet; molecules near the center of the droplet are not coupled to high Q resonances while molecules near the surface may strongly interact with cavity resonances associated with droplet. Thus, diffusion limits the amount of time a given molecule may interact with the resonances thereby limiting the fluorescence decay rate. Second, the fluorescence decay rate depends on the orientation of the transition moment with respect to the cavity "axis"; e.g., the surface normal for spherical cavities.
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Kung, C.-Y., M. D. Barnes, N. Lermer, W. B. Whitten, and J. M. Ramsey. "Confinement, Detection, and Manipulation of Individual Molecules in Attoliter Volumes." In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/lacea.1998.lma.4.
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We report observation of fluorescence from individual rhodamine 6G molecules in streams of charged 1-μm diameter water droplets. With this approach, probe volumes comparable to diffraction-limited fluorescence microscopy1 techniques (≤ 500 attoliters) are achieved, resulting in similarly high contrast between single molecule fluorescence signals and nonfluorescent background. However, since the fluorescent molecules are confined to electrically charged droplets, in situ electrodynamic manipulation can be accomplished in a straightforward manner, allowing experimental control over both the delivery of molecules of interest to the observation region and the laser-molecule interaction time.
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Lermer, N., M. D. Barnes, C.-Y. Kung, W. B. Whitten, and J. M. Ramsey. "High-Speed Single Molecule Detection in Microdroplet Streams." In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/lacea.1996.lwb.7.
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The detection of individual fluorescent molecules in liquids has been of great interest in recent years. Various fluorescence-based techniques shown to provide single molecule sensitivities include confocal microscopy [1], flow cell techniques [2], and levitated microdroplets [3]. The application of the microdroplet technique to single molecule detection offers many advantages. First, fluoresence decay rates and total fluoresence yield have been shown to be enhanced in glycerol microdroplets [4]. Additionally, the droplet confines the single fluorophore to a small volume thereby removing difficulties arising from diffusion of the fluorophore. Furthermore, the discrete detection unit of the droplet is ideally suited to the application of digital molecular detection for the analysis of ultradilute solutions [5]. Previous liquid microdroplet work has exhibited single molecule detection with signal-to-noise ratios in the range of 10-40 [3]. In our previous work, an electrodynamic trap was employed to trap glycerol microdroplets for a period much longer than the average photochemical lifetime, thus obtaining the maximum possible signal from the analyte. However, the application of digital molecular analysis to real systems requires tens of thousands of droplet measurements [5]; the time required to trap (and to size) the droplet in a levitated system prohibits its application in a high-speed molecular counting technique. In addition, many biological applications of single molecule fluorescence detection require aqueous samples. The present work discusses the development of an instrument designed to permit single molecule detection in water microdroplets at count rates in the range of 10 - 1000 Hz.
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Schade, W., and T. Blanke. "Diode-Laser-Based Detection of BTXE-Aromatics in Oil Polluted Soil Samples." In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/lacea.1996.lfb.3.
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The generation of tunable laser radiation in the spectral range between 4 and 10 µm is of general interest for the spectroscopy since most of the fundamental vibrational modes of molecules are within this spectral region [1]. There exist several conventional tunable cw-laser systems, like lead salt-diodes, color center-, optical parametric-, and CO or CO2 side band lasers. However, they need cryogenic cooling, do not cover all spectral regions that are of general interest for the spectroscopy and in most cases they are very complicated and complex laser sources. This limits the possibilities for practical applications of mid-infrared absorption spectroscopy, e.g. in the trace analysis of environmental pollutants. Therefore there is still a lack in simple, compact, portable, and rugged mid-infrared laser sources. In this context diode-lasers and difference frequency generation (DFG) in new nonlinear media such as AgGaS2 have drawn considerable interest in the construction of compact cw laser spectrometers [2,3].
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Blanke, Torsten, Ulrike Willer, Dietmar Kracht, and Wolfgang Schade. "Diode-Laser-Difference Frequency Spectrometer for Carbon Monoxide Detection." In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/lacea.1998.lmc.10.
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The application of laser absorption spectroscopy for remote sensing of environmental pollutants in the mid-infrared spectral range (MIR) is of fundamental interest, because most of the relevant molecules have strong vibrational transitions in this spectral region that can be used as “fingerprint” for a sensitive detection in complex environments, as air, water or soil. However, there is still a lack in simple, compact, portable and rugged MIR laser sources. In this context, diode-lasers and difference frequency generation recently have drawn considerable interest [1-3]. New and efficient nonlinear crystals, as e.g. AgGaS2 or GaAsSe, and recent progress in the fabrication of fiber optics for the MIR make it possible to set up compact MIR laser spectrometers with the option of evanescent field spectroscopy. The latter one is of essential advantage when a detection of pollutants in optical thick media, e.g. soil, is required.
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Hubschmid, W., R. Bombach, and B. Hemmerling. "Laser-Induced Gratings in the Red System of Molecular Oxygen." In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/lacea.1996.lthd.1.
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Energy transfer processes involving singlet states of O2 are of great and continuous interest in atmospheric and biological research. Due to the low excitation energies the states 1Δg, and 1 Σ g + are studied most extensively. The forbidden nature of optical transitions to the ground state makes the singlet molecules metastable. Thus, quite slow nonradiative processes can be studied. The singlet states of oxygen offer therefore a good possibility to analyse different contributions to laser-induced gratings. On the other hand, the analysis of the temporal evolution of the laser-induced gratings may prove to be a powerful method to study energy transfer processes.
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Preppernau, B. L., and P. J. Hargis. "Trace Organic Chemical Detection Using an Ultraviolet Excitation Molecular Beam Fluorometer." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/laca.1994.tub.5.
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Detection of air-borne environmental contaminants, such as organic solvents, requires unambiguous compound identification and sensitivity to concentrations below those permitted by regulating agencies. One promising detection approach uses a pulsed supersonic molecular beam vacuum expansion in combination with fluorescence signal spectral analysis to identify species in a chemical mixture. Expanding a contaminated atmospheric sample through a supersonic molecular beam expansion acts to cool the sample and greatly reduce the spectral density in a fluorescence or photoionization spectrum. Most organic contaminants of interest have electronic transitions in the ultraviolet with near-featureless broad band fluorescence spectra when recorded at atmospheric pressure and room temperature. By using a supersonic vacuum expansion, cooling to within a few degrees of absolute zero can reduce the effective rotational and translational temperatures of the sample molecules and provide a sharply defined spectra which can be used to unambiguously identify specific molecules and their concentrations.
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Zhang, Wujie, Kyle Gilstrap, Laying Wu, Melissa A. Moss, Qian Wang, Xiongbin Lu, and Xiaoming He. "Controlled Release and Intracellular Delivery of Small Molecules Using Thermally Responsive Pluronic F127-Chitosan Nanocapsules." In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53517.
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Nanoscale particulate systems have been studied as the delivery vehicle of various drugs and therapeutic agents for decades with promising outcomes. Recently, nano-particulate systems that are responsive to one or more environmental stimuli (such as temperature, pH, and electromagnetic field) are attracting increasing attention because they allow drug delivery and release to be done in a more controllable fashion [1]. The thermally (temperature) responsive nanoparticles are of particular interest to many researchers because the temperature controlled release of the encapsulated drug can be conveniently done with either thermo (using supraphysiologic temperatures) or cryo (using sub-zero temperature) therapies, minimally invasive energy-based surgical techniques that have been widely studied as potential alternatives to radical surgical intervention for the treatment of cancer and other diseases. Moreover, a significantly improved outcome of cancer treatment has been reported by combining thermotherapy (using supraphysiologic temperatures) and anticancer drug encapsulated in thermally responsive nanoparticles [2]. Here, we report thermally responsive nanocapsules that can be combined with cryotherapy for cancer treatment.
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Xu, Dongyan, Deyu Li, and Yongsheng Leng. "Molecular Dynamics Simulations of Water and Ion Structures Near Charged Surfaces." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42536.
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Extensive research has been devoted to nanofluidics in the past decade because of its potential applications in single molecule sensing and manipulations. Fundamental studies have attracted significant attention in this research field since the success of nanofluidic devices depends on a thorough understanding of the fluidic, ionic, and molecular behavior in highly confined nano-environments. In this paper, we report on molecular dynamics simulations of the effect of surface charge densities on the ion distribution and the water density profile close to a charged surface. We demonstrate that surface charges not only interact with mobile ions in the electrolyte, but also interact with water molecules due to their polarizability, and hence influence the orientation of water molecules in the near wall region. For the first time, we show that as the surface charge density increases, the water molecules within ∼ 5 Å of the {100} silicon surface will evolve from one layer into two layers. Meanwhile, the orientation of the water molecules is more aligned instead of randomly distributed. This layering effect may have important implications on electroosmotic flow through nanochannels and heat transfer across the solid-liquid interface.
Reports on the topic "Molecules - Environmental Interest"
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Ron, Eliora, and Eugene Eugene Nester. Global functional genomics of plant cell transformation by agrobacterium. United States Department of Agriculture, March 2009. http://dx.doi.org/10.32747/2009.7695860.bard.
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The aim of this study was to carry out a global functional genomics analysis of plant cell transformation by Agrobacterium in order to define and characterize the physiology of Agrobacterium in the acidic environment of a wounded plant. We planed to study the proteome and transcriptome of Agrobacterium in response to a change in pH, from 7.2 to 5.5 and identify genes and circuits directly involved in this change. Bacteria-plant interactions involve a large number of global regulatory systems, which are essential for protection against new stressful conditions. The interaction of bacteria with their hosts has been previously studied by genetic-physiological methods. We wanted to make use of the new capabilities to study these interactions on a global scale, using transcription analysis (transcriptomics, microarrays) and proteomics (2D gel electrophoresis and mass spectrometry). The results provided extensive data on the functional genomics under conditions that partially mimic plant infection and – in addition - revealed some surprising and significant data. Thus, we identified the genes whose expression is modulated when Agrobacterium is grown under the acidic conditions found in the rhizosphere (pH 5.5), an essential environmental factor in Agrobacterium – plant interactions essential for induction of the virulence program by plant signal molecules. Among the 45 genes whose expression was significantly elevated, of special interest is the two-component chromosomally encoded system, ChvG/I which is involved in regulating acid inducible genes. A second exciting system under acid and ChvG/Icontrol is a secretion system for proteins, T6SS, encoded by 14 genes which appears to be important for Rhizobium leguminosarum nodule formation and nitrogen fixation and for virulence of Agrobacterium. The proteome analysis revealed that gamma aminobutyric acid (GABA), a metabolite secreted by wounded plants, induces the synthesis of an Agrobacterium lactonase which degrades the quorum sensing signal, N-acyl homoserine lactone (AHL), resulting in attenuation of virulence. In addition, through a transcriptomic analysis of Agrobacterium growing at the pH of the rhizosphere (pH=5.5), we demonstrated that salicylic acid (SA) a well-studied plant signal molecule important in plant defense, attenuates Agrobacterium virulence in two distinct ways - by down regulating the synthesis of the virulence (vir) genes required for the processing and transfer of the T-DNA and by inducing the same lactonase, which in turn degrades the AHL. Thus, GABA and SA with different molecular structures, induce the expression of these same genes. The identification of genes whose expression is modulated by conditions that mimic plant infection, as well as the identification of regulatory molecules that help control the early stages of infection, advance our understanding of this complex bacterial-plant interaction and has immediate potential applications to modify it. We expect that the data generated by our research will be used to develop novel strategies for the control of crown gall disease. Moreover, these results will also provide the basis for future biotechnological approaches that will use genetic manipulations to improve bacterial-plant interactions, leading to more efficient DNA transfer to recalcitrant plants and robust symbiosis. These advances will, in turn, contribute to plant protection by introducing genes for resistance against other bacteria, pests and environmental stress.
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Chamovitz, Daniel A., and Zhenbiao Yang. Chemical Genetics of the COP9 Signalosome: Identification of Novel Regulators of Plant Development. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7699844.bard.
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This was an exploratory one-year study to identify chemical regulators of the COP9 signalosome. Chemical Genetics uses small molecules to modify or disrupt the function of specific genes/proteins. This is in contrast to classical genetics, in which mutations disrupt the function of genes. The underlying concept is that the functions of most proteins can be altered by the binding of a chemical, which can be found by screening large libraries for compounds that specifically affect a biological, molecular or biochemical process. In addition to screens for chemicals which inhibit specific biological processes, chemical genetics can also be employed to find inhibitors of specific protein-protein interactions. Small molecules altering protein-protein interactions are valuable tools in probing protein-protein interactions. In this project, we aimed to identify chemicals that disrupt the COP9 signalosome. The CSN is an evolutionarily conserved eight-subunit protein complex whose most studied role is regulation of E3 ubiquitinligase activity. Mutants in subunits of the CSN undergo photomorphogenesis in darkness and accumulate high levels of pigments in both dark- and light-grown seedlings, and are defective in a wide range of important developmental and environmental-response pathways. Our working hypothesis was that specific molecules will interact with the CSN7 protein such that binding to its various interacting proteins will be inhibited. Such a molecule would inhibit either CSN assembly, or binding of CSN-interacting proteins, and thus specifically inhibit CSN function. We used an advanced chemical genetic screen for small-molecule-inhibitors of CSN7 protein-protein interactions. In our pilot study, following the screening of ~1200 unique compounds, we isolated four chemicals which reproducibly interfere with CSN7 binding to either CSN8 or CSN6.
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Stern, David, and Gadi Schuster. Manipulation of Gene Expression in the Chloroplast. United States Department of Agriculture, September 2000. http://dx.doi.org/10.32747/2000.7575289.bard.
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The steady-state level of a given mRNA is determined by its rates of transcription and degradation. The stabilities of chloroplast mRNAs vary during plant development, in part regulating gene expression. Furthermore, the fitness of the organelle depends on its ability to destroy non-functional transcripts. In addition, there is a resurgent interest by the biotechnology community in chloroplast transformation due to the public concerns over pollen transmission of introduced traits or foreign proteins. Therefore, studies into basic gene expression mechanisms in the chloroplast will open the door to take advantage of these opportunities. This project was aimed at gaining mechanistic insights into mRNA processing and degradation in the chloroplast and to engineer transcripts of varying stability in Chlamydomonas reinhardtii cells. This research uncovered new and important information on chloroplast mRNA stability, processing, degradation and translation. In particular, the processing of the 3' untranslated regions of chloroplast mRNAs was shown to be important determinants in translation. The endonucleolytic site in the 3' untranslated region was characterized by site directed mutagensis. RNA polyadenylation has been characterized in the chloroplast of Chlamydomonas reinhardtii and chloroplast transformants carrying polyadenylated sequences were constructed and analyzed. Data obtained to date suggest that chloroplasts have gene regulatory mechanisms which are uniquely adapted to their post-endosymbiotic environment, including those that regulate RNA stability. An exciting point has been reached, because molecular genetic studies have defined critical RNA-protein interactions that participate in these processes. However, much remains to be learned about these multiple pathways, how they interact with each other, and how many nuclear genes are consecrated to overseeing them. Chlamydomonas is an ideal model system to extend our understanding of these areas, given its ease of manipulation and the existing knowledge base, some of which we have generated.
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Wagner, D. Ry, Eliezer Lifschitz, and Steve A. Kay. Molecular Genetic Analysis of Flowering in Arabidopsis and Tomato. United States Department of Agriculture, May 2002. http://dx.doi.org/10.32747/2002.7585198.bard.
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The primary objectives for the US lab included: the characterization of ELF3 transcription and translation; the creation and characterization of various transgenic lines that misexpress ELF3; defining genetic pathways related to ELF3 function regulating floral initiation in Arabidopsis; and the identification of genes that either interact with or are regulated by ELF3. Light quality, photoperiod, and temperature often act as important and, for some species, essential environmental cues for the initiation of flowering. However, there is relatively little information on the molecular mechanisms that directly regulate the developmental pathway from the reception of the inductive light signals to the onset of flowering and the initiation of floral meristems. The ELF3 gene was identified as possibly having a role in light-mediated floral regulation since elj3 mutants not only flower early, but exhibit light-dependent circadian defects. We began investigating ELF3's role in light signalling and flowering by cloning the ELF3 gene. ELF3 is a novel gene only present in plant species; however, there is an ELF3 homolog within Arabidopsis. The Arabidopsis elj3 mutation causes arrhythmic circadian output in continuous light; however, we show conclusively normal circadian function with no alteration of period length in elj3 mutants in dark conditions and that the light-dependent arrhythmia observed in elj3 mutants is pleiotropic on multiple outputs regardless of phase. Plants overexpressing ELF3 have an increased period length in constant light and flower late in long-days; furthermore, etiolated ELF3-overexpressing seedlings exhibit a decreased acute CAB2 response after a red light pulse, whereas the null mutant is hypersensitive to acute induction. This finding suggests that ELF3 negatively regulates light input to both the clock and its outputs. To determine whether ELF3's action is phase dependent, we examined clock resetting by light pulses and constructed phase response curves. Absence of ELF3 activity causes a significant alteration of the phase response curve during the subjective night, and overexpression of ELF3 results in decreased sensitivity to the resetting stimulus, suggesting that ELF3 antagonizes light input to the clock during the night. Indeed, the ELF3 protein interacts with the photoreceptor PHYB in the yeast two-hybrid assay and in vitro. The phase ofELF3 function correlates with its peak expression levels of transcript and protein in the subjective night. ELF3 action, therefore, represents a mechanism by which the oscillator modulates light resetting. Furthermore, flowering time is dependent upon proper expression ofELF3. Scientifically, we've made a big leap in the understanding of the circadian system and how it is coupled so tightly with light reception in terms of period length and clock resetting. Agriculturally, understanding more about the way in which the clock perceives and relays temporal information to pathways such as those involved in the floral transition can lead to increased crop yields by enabling plants to be grown in suboptimal conditions.
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Gurevitz, Michael, Michael E. Adams, and 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, August 1995. http://dx.doi.org/10.32747/1995.7573061.bard.
Full textAbstract:
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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Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion, and Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, October 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
Full textAbstract:
Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.
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Borch, Thomas, Yitzhak Hadar, and Tamara Polubesova. Environmental fate of antiepileptic drugs and their metabolites: Biodegradation, complexation, and photodegradation. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597927.bard.
Full textAbstract:
Many pharmaceutical compounds are active at very low doses, and a portion of them regularly enters municipal sewage systems and wastewater-treatment plants following use, where they often do not fully degrade. Two such compounds, CBZ and LTG, have been detected in wastewater effluents, surface waters, drinking water, and irrigation water, where they pose a risk to the environment and the food supply. These compounds are expected to interact with organic matter in the environment, but little is known about the effect of such interactions on their environmental fate and transport. The original objectives of our research, as defined in the approved proposal, were to: Determine the rates, mechanisms and products of photodegradation of LTG, CBZ and selected metabolites in waters exposed to near UV light, and the influence of DOM type and binding processes on photodegradation. Determine the potential and pathways for biodegradation of LTG, CBZ and selected metabolites using a white rot fungus (Pleurotusostreatus) and ADP, and reveal the effect of DOM complexation on these processes. Reveal the major mechanisms of binding of LTG, CBZ and selected metabolites to DOM and soil in the presence of DOM, and evaluate the effect of this binding on their photodegradation and/or biodegradation. We determined that LTG undergoes relatively slow photodegradation when exposed to UV light, and that pH affects each of LTG’s ability to absorb UV light, the efficiency of the resulting reaction, and the identities of LTG’sphotoproducts (t½ = 230 to 500 h during summer at latitude 40 °N). We observed that LTG’sphotodegradation is enhanced in the presence of DOM, and hypothesized that LTG undergoes direct reactions with DOM components through nucleophilic substitution reactions. In combination, these data suggest that LTG’s fate and transport in surface waters are controlled by environmental conditions that vary with time and location, potentially affecting the environment and irrigation waters. We determined that P. ostreatusgrows faster in a rich liquid medium (glucose peptone) than on a natural lignocellulosic substrate (cotton stalks) under SSF conditions, but that the overall CBZ removal rate was similar in both media. Different and more varied transformation products formed in the solid state culture, and we hypothesized that CBZ degradation would proceed further when P. ostreatusand the ᵉⁿᶻʸᵐᵃᵗⁱᶜ ᵖʳᵒᶠⁱˡᵉ ʷᵉʳᵉ ᵗᵘⁿᵉᵈ ᵗᵒ ˡⁱᵍⁿⁱⁿ ᵈᵉᵍʳᵃᵈᵃᵗⁱᵒⁿ. ᵂᵉ ᵒᵇˢᵉʳᵛᵉᵈ ¹⁴C⁻Cᴼ2 ʳᵉˡᵉᵃˢᵉ ʷʰᵉⁿ ¹⁴C⁻ᶜᵃʳᵇᵒⁿʸˡ⁻ labeled CBZ was used as the substrate in the solid state culture (17.4% of the initial radioactivity after 63 days of incubation), but could not conclude that mineralization had occurred. In comparison, we determined that LTG does not degrade in agricultural soils irrigated with treated wastewater, but that P. ostreatusremoves up to 70% of LTG in a glucose peptone medium. We detected various metabolites, including N-oxides and glycosides, but are still working to determine the degradation pathway. In combination, these data suggest that P. ostreatuscould be an innovative and effective tool for CBZ and LTG remediation in the environment and in wastewater used for irrigation. In batch experiments, we determined that the sorption of LTG, CBZ and selected metabolites to agricultural soils was governed mainly by SOM levels. In lysimeter experiments, we also observed LTG and CBZ accumulation in top soil layers enriched with organic matter. However, we detected CBZ and one of its metabolites in rain-fed wheat previously irrigated with treated wastewater, suggesting that their sorption was reversible, and indicating the potential for plant uptake and leaching. Finally, we used macroscale analyses (including adsorption/desorption trials and resin-based separations) with molecular- level characterization by FT-ICR MS to demonstrate the adsorptive fractionation of DOM from composted biosolids by mineral soil. This suggests that changes in soil and organic matter types will influence the extent of LTG and CBZ sorption to agricultural soils, as well as the potential for plant uptake and leaching.
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Brown Horowitz, Sigal, Eric L. Davis, and Axel Elling. Dissecting interactions between root-knot nematode effectors and lipid signaling involved in plant defense. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598167.bard.
Full textAbstract:
Root-knot nematodes, Meloidogynespp., are extremely destructive pathogens with a cosmopolitan distribution and a host range that affects most crops. Safety and environmental concerns related to the toxicity of nematicides along with a lack of natural resistance sources threaten most crops in Israel and the U.S. This emphasizes the need to identify genes and signal mechanisms that could provide novel nematode control tactics and resistance breeding targets. The sedentary root-knot nematode (RKN) Meloidogynespp. secrete effectors in a spatial and temporal manner to interfere with and mimic multiple physiological and morphological mechanisms, leading to modifications and reprogramming of the host cells' functions, resulted in construction and maintenance of nematodes' feeding sites. For successful parasitism, many effectors act as immunomodulators, aimed to manipulate and suppress immune defense signaling triggered upon nematode invasion. Plant development and defense rely mainly on hormone regulation. Herein, a metabolomic profiling of oxylipins and hormones composition of tomato roots were performed using LC-MS/MS, indicating a fluctuation in oxylipins profile in a compatible interaction. Moreover, further attention was given to uncover the implication of WRKYs transcription factors in regulating nematode development. In addition, in order to identify genes that might interact with the lipidomic defense pathway induced by oxylipins, a RNAseq was performed by exposing M. javanicasecond-stage juveniles to tomato protoplast, 9-HOT and 13-KOD oxylipins. This transcriptome generated a total of 4682 differentially expressed genes (DEGs). Being interested in effectors, we seek for DEGs carrying a predicted secretion signal peptide. Among the DEGs including signal peptide, several had homology with known effectors in other nematode species, other unknown potentially secreted proteins may have a role as root-knot nematodes' effectors which might interact with lipid signaling. The molecular interaction of LOX proteins with the Cyst nematode effectors illustrate the nematode strategy in manipulating plant lipid signals. The function of several other effectors in manipulating plant defense signals, as well as lipids signals, weakening cell walls, attenuating feeding site function and development are still being studied in depth for several novel effectors. As direct outcome of this project, the accumulating findings will be utilized to improve our understanding of the mechanisms governing critical life-cycle phases of the parasitic M. incognita RKN, thereby facilitating design of effective controls based on perturbation of nematode behavior—without producing harmful side effects. The knowledge from this study will promote genome editing strategies aimed at developing nematode resistance in tomato and other nematode-susceptible crop species in Israel and the United States.
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Avni, Adi, and Gitta L. Coaker. Proteomic investigation of a tomato receptor like protein recognizing fungal pathogens. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600030.bard.
Full textAbstract:
Maximizing food production with minimal negative effects on the environment remains a long-term challenge for sustainable food production. Microbial pathogens cause devastating diseases, minimizing crop losses by controlling plant diseases can contribute significantly to this goal. All plants possess an innate immune system that is activated after recognition of microbial-derived molecules. The fungal protein Eix induces defense responses in tomato and tobacco. Plants recognize Eix through a leucine-rich-repeat receptor- like-protein (LRR-RLP) termed LeEix. Despite the knowledge obtained from studies on tomato, relatively little is known about signaling initiated by RLP-type immune receptors. The focus of this grant proposal is to generate a foundational understanding of how the tomato xylanase receptor LeEix2 signals to confer defense responses. LeEix2 recognition results in pattern triggered immunity (PTI). The grant has two main aims: (1) Isolate the LeEix2 protein complex in an active and resting state; (2) Examine the biological function of the identified proteins in relation to LeEix2 signaling upon perception of the xylanase elicitor Eix. We used two separate approaches to isolate receptor interacting proteins. Transgenic tomato plants expressing LeEix2 fused to the GFP tag were used to identify complex components at a resting and activated state. LeEix2 complexes were purified by mass spectrometry and associated proteins identified by mass spectrometry. We identified novel proteins that interact with LeEix receptor by proteomics analysis. We identified two dynamin related proteins (DRPs), a coiled coil – nucleotide binding site leucine rich repeat (SlNRC4a) protein. In the second approach we used the split ubiquitin yeast two hybrid (Y2H) screen system to identified receptor-like protein kinase At5g24010-like (SlRLK-like) (Solyc01g094920.2.1) as an interactor of LeEIX2. We examined the role of SlNRC4a in plant immunity. Co-immunoprecipitation demonstrates that SlNRC4a is able to associate with different PRRs. Physiological assays with specific elicitors revealed that SlNRC4a generally alters PRR-mediated responses. SlNRC4a overexpression enhances defense responses while silencing SlNRC4 reduces plant immunity. We propose that SlNRC4a acts as a non-canonical positive regulator of immunity mediated by diverse PRRs. Thus, SlNRC4a could link both intracellular and extracellular immune perception. SlDRP2A localizes at the plasma membrane. Overexpression of SlDRP2A increases the sub-population of LeEIX2 inVHAa1 endosomes, and enhances LeEIX2- and FLS2-mediated defense. The effect of SlDRP2A on induction of plant immunity highlights the importance of endomembrane components and endocytosis in signal propagation during plant immune . The interaction of LeEIX2 with SlRLK-like was verified using co- immunoprecipitation and a bimolecular fluorescence complementation assay. The defence responses induced by EIX were markedly reduced when SlRLK-like was over-expressed, and mutation of slrlk-likeusing CRISPR/Cas9 increased EIX- induced ethylene production and SlACSgene expression in tomato. Co-expression of SlRLK-like with different RLPs and RLKs led to their degradation, apparently through an endoplasmic reticulum-associated degradation process. We provided new knowledge and expertise relevant to expression of specific be exploited to enhance immunity in crops enabling the development of novel environmentally friendly disease control strategies.
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Chefetz, Benny, and Jon Chorover. Sorption and Mobility of Pharmaceutical Compounds in Soils Irrigated with Treated Wastewater. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7592117.bard.
Full textAbstract:
Research into the fate of pharmaceutical compounds (PCs) in the environment has focused on aspects of removal efficiency during sewage treatment, degradation in surface water and accumulation in soils and sediments. However, very little information is available on the binding interactions of pharmaceuticals with dissolved organic matter (DOM) originating from wastewater treatment. Such interactions can significantly affect the transport potential of PCs in soils by altering compound affinity for soil particle surfaces. Our primary hypothesis is that the transport potential of PCs in soils is strongly impacted by the type and strength of interaction with DOM and the stability of resulting DOM-PC complexes. The overarching goal of the proposed work is to develop a better understanding of the risk associated with introduction of PCs into the environment with treated wastewater. This goal has been achieved by elucidating the mechanisms of the interaction of selected pharmaceuticals (that have shown to be widespread wastewater contaminants) with DOM constituents; by determining the stability and fate of DOM-PC complexes introduced to soils and soil constituents; and by evaluating the potential uptake of these compounds by plants. Based on the results obtained in this study (column and batch sorption-desorption experiments), we suggest that PCs can be classified as slow-mobile compounds in SOM-rich soil layers. When these compounds pass this layer and/or are introduced into SOM-poor soils, their mobility increases significantly. Our data suggest that in semiarid soils (consisting of low SOM), PCs can potentially be transported to the groundwater in fields irrigated with reclaimed wastewater. Moreover, the higher mobility of the acid PCs (i.e., naproxen and diclofenac) in freshwater column systems suggests that their residues in soils irrigated with reclaimed wastewater can leach from the root zone and be transported to the groundwater after rain events. Our data obtained from the binding experiments of PCs with DOM demonstrate that the hydrophobic DOM fractions were more efficient at sorbing PCs than the more polar hydrophilic fractions at a pH near the pKa of the analytes. At the pH of natural semiarid water and soil systems, including that of reclaimed wastewater and biosolids, the role of the hydrophobic fractions as sorption domains is less important than the contribution of the hydrophilic fractions. We also hypothesize that the DOM fractions interact with each other at the molecular level and do not act as independent sorption domains. In summary, our data collected in the BARD project demonstrate that the sorption abilities of the DOM fractions can also significantly affect the mobility of pharmaceutical compounds in soils influenced by intensive irrigation with treated wastewater or amended with biosolids.