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  • 1
    Online Resource
    Online Resource
    Synapse-specific IL-1 receptor subunit reconfiguration augments vulnerability to IL-1β in the aged hippocampus
    Proceedings of the National Academy of Sciences ; 2015
    In:  Proceedings of the National Academy of Sciences Vol. 112, No. 36 ( 2015-09-08)
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 112, No. 36 ( 2015-09-08)
    Abstract: In the aged brain, synaptic plasticity and memory show increased vulnerability to impairment by the inflammatory cytokine interleukin 1β (IL-1β). In this study, we evaluated the possibility that synapses may directly undergo maladaptive changes with age that augment sensitivity to IL-1β impairment. In hippocampal neuronal cultures, IL-1β increased the expression of the IL-1 receptor type 1 and the accessory coreceptor AcP (proinflammatory), but not of the AcPb (prosurvival) subunit, a reconfiguration that potentiates the responsiveness of neurons to IL-1β. To evaluate whether synapses develop a similar heightened sensitivity to IL-1β with age, we used an assay to track long-term potentiation (LTP) in synaptosomes. We found that IL-1β impairs LTP directly at the synapse and that sensitivity to IL-1β is augmented in aged hippocampal synapses. The increased synaptic sensitivity to IL-1β was due to IL-1 receptor subunit reconfiguration, characterized by a shift in the AcP/AcPb ratio, paralleling our culture data. We suggest that the age-related increase in brain IL-1β levels drives a shift in IL-1 receptor configuration, thus heightening the sensitivity to IL-1β. Accordingly, selective blocking of AcP-dependent signaling with Toll–IL-1 receptor domain peptidomimetics prevented IL-1β–mediated LTP suppression and blocked the memory impairment induced in aged mice by peripheral immune challenge (bacterial lipopolysaccharide). Overall, this study demonstrates that increased AcP signaling, specifically at the synapse, underlies the augmented vulnerability to cognitive impairment by IL-1β that occurs with age.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1514486112
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2015
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  • 2
    Online Resource
    Online Resource
    Catalytic detoxification of nerve agent and pesticide organophosphates by butyrylcholinesterase assisted with non-pyridinium oximes
    Portland Press Ltd. ; 2013
    In:  Biochemical Journal Vol. 450, No. 1 ( 2013-02-15), p. 231-242
    Details
    In: Biochemical Journal, Portland Press Ltd., Vol. 450, No. 1 ( 2013-02-15), p. 231-242
    Abstract: In the present paper we show a comprehensive in vitro, ex vivo and in vivo study on hydrolytic detoxification of nerve agent and pesticide OPs (organophosphates) catalysed by purified hBChE (human butyrylcholinesterase) in combination with novel non-pyridinium oxime reactivators. We identified TAB2OH (2-trimethylammonio-6-hydroxybenzaldehyde oxime) as an efficient reactivator of OP–hBChE conjugates formed by the nerve agents VX and cyclosarin, and the pesticide paraoxon. It was also functional in reactivation of sarin- and tabun-inhibited hBChE. A 3–5-fold enhancement of in vitro reactivation of VX-, cyclosarin- and paraoxon-inhibited hBChE was observed when compared with the commonly used N-methylpyridinium aldoxime reactivator, 2PAM (2-pyridinealdoxime methiodide). Kinetic analysis showed that the enhancement resulted from improved molecular recognition of corresponding OP–hBChE conjugates by TAB2OH. The unique features of TAB2OH stem from an exocyclic quaternary nitrogen and a hydroxy group, both ortho to an oxime group on a benzene ring. pH-dependences reveal participation of the hydroxy group (pKa=7.6) forming an additional ionizing nucleophile to potentiate the oxime (pKa=10) at physiological pH. The TAB2OH protective indices in therapy of sarin- and paraoxon-exposed mice were enhanced by 30–60% when they were treated with a combination of TAB2OH and sub-stoichiometric hBChE. The results of the present study establish that oxime-assisted catalysis is feasible for OP bioscavenging.
    Type of Medium: Online Resource
    ISSN: 0264-6021 , 1470-8728
    URL: Article
    DOI: 10.1042/BJ20121612
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    WA 15000
    Language: English
    Publisher: Portland Press Ltd.
    Publication Date: 2013
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  • 3
    Online Resource
    Online Resource
    Regeneration of Carbonyl Compounds from Oximes under Microwave Irradiation in Solventless System
    Walter de Gruyter GmbH ; 2000
    In:  Zeitschrift für Naturforschung B Vol. 55, No. 5 ( 2000-5-1), p. 431-433
    Details
    In: Zeitschrift für Naturforschung B, Walter de Gruyter GmbH, Vol. 55, No. 5 ( 2000-5-1), p. 431-433
    Abstract: A new, mild, efficient and environm entally benign method for the cleavage of oximes has been achieved by a simple reaction f oximes with wet alumina supported chromium (VI) oxide under microwave irradiations in solvent-free condition.
    Type of Medium: Online Resource
    ISSN: 1865-7117 , 0932-0776
    URL: Article
    DOI: 10.1515/znb-2000-0513
    RVK:
    WA 15000
    RVK:
    VA 8360
    Language: English
    Publisher: Walter de Gruyter GmbH
    Publication Date: 2000
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    detail.hit.zdb_id: 124635-5
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  • 4
    Online Resource
    Online Resource
    Adaptations of guest and host in expanded self-assembled capsules
    Proceedings of the National Academy of Sciences ; 2007
    In:  Proceedings of the National Academy of Sciences Vol. 104, No. 41 ( 2007-10-09), p. 16000-16003
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 104, No. 41 ( 2007-10-09), p. 16000-16003
    Abstract: Reversible encapsulation complexes create spaces where two or more molecules can be temporarily isolated. When the mobility of encapsulated molecules is restricted, different arrangements in space are possible, and new forms of isomerism (“social isomerism”) are created: the orientation of one encapsulated molecule influences that of the other in the confined space. Expansion of a capsule's length is possible through addition of small-molecule spacer elements. The expanded capsules have dimensions that permit the observation of social isomerism of two identical guests, and they adopt arrangements that properly fill the host's space. The host also can adapt to longer guests by incorporating additional spacers, much as protein modules are added to a viral capsid in response to larger genomes. Arachidonic and related fatty acid derivatives act in this way to induce the assembly of further extended capsules having sufficient length to accommodate them.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0707759104
    RVK:
    TA 1000
    RVK:
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    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2007
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  • 5
    Online Resource
    Online Resource
    Recognition and sequestration of ω-fatty acids by a cavitand receptor
    Proceedings of the National Academy of Sciences ; 2015
    In:  Proceedings of the National Academy of Sciences Vol. 112, No. 36 ( 2015-09-08), p. 11181-11186
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 112, No. 36 ( 2015-09-08), p. 11181-11186
    Abstract: One of the largest driving forces for molecular association in aqueous solution is the hydrophobic effect, and many synthetic receptors with hydrophobic interiors have been devised for molecular recognition studies in water. Attempts to create the longer, narrower cavities appropriate for long-chain fatty acids have been thwarted by solvophobic collapse of the synthetic receptors, giving structures that have no internal spaces. The collapse generally involves the stacking of aromatic panels onto themselves. We describe here the synthesis and application of a deep cavitand receptor featuring “prestacked” aromatic panels at the upper rim of the binding pocket. The cavitand remains open and readily sequesters biologically relevant long-chain molecules—unsaturated ω-3, -6, and -9 fatty acids and derivatives such as anandamide—from aqueous media. The cavitand exists in isomeric forms with different stacking geometries and n -alkanes were used to characterize the binding modes and conformational properties. Long alkyl chains are accommodated in inverted J-shaped conformations. An analogous cavitand with electron-rich aromatic walls was prepared and comparative binding experiments indicated the role of intramolecular stacking in the binding properties of these deep container molecules.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1515233112
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2015
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    detail.hit.zdb_id: 1461794-8
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    SSG: 12
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  • 6
    Online Resource
    Online Resource
    Experimental and computational probes of the space in a self-assembled capsule
    Proceedings of the National Academy of Sciences ; 2006
    In:  Proceedings of the National Academy of Sciences Vol. 103, No. 24 ( 2006-06-13), p. 8934-8936
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 103, No. 24 ( 2006-06-13), p. 8934-8936
    Abstract: Self-assembled capsules are hosts that recognize and surround smaller molecule guests of appropriate size, shape, and chemical surfaces. The space available inside is a cage of fixed solvent molecules, many of which are aromatic. These aromatics provide anisotropic shielding to guests, and a map of induced magnetic shielding for the inner space can be obtained through nucleus-independent chemical shift calculations. Experimental values of the magnetic environment can be determined by NMR spectra of the guests inside. We describe here the environment in a cylindrical capsule with tapered ends. A series of terminal acetylenes—the narrowest of organic structures—was synthesized and used to probe the magnetic shielding of the capsule’s ends. Their NMR spectra showed that the acetylenic hydrogen experiences deshielding as it is forced deeper into the tapered end of the capsule where four benzene rings converge. Modeling and density functional theory calculations provided excellent agreement with the experimental values and established a molecular ruler to explore steric and magnetic environments inside the capsule.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0602781103
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2006
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    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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  • 7
    Online Resource
    Online Resource
    Autocatalysis and organocatalysis with synthetic structures
    Proceedings of the National Academy of Sciences ; 2010
    In:  Proceedings of the National Academy of Sciences Vol. 107, No. 2 ( 2010-01-12), p. 541-544
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 107, No. 2 ( 2010-01-12), p. 541-544
    Abstract: The discovery of ribozymes led to the proposal of an RNA world, where a single type of molecule was supposedly capable of self-replication and chemical catalysis. We show here that both autocatalysis and organocatalysis can be engineered into a synthetic structure. The compound is shown to selectively accelerate its own formation and catalyze either hydrogenation or nucleophilic addition to α,β-unsaturated aldehydes. The observed reactivity indicates that the components of a purported pre-RNA world conceivably include smaller organic molecules.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0912769107
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2010
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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  • 8
    Online Resource
    Online Resource
    Disproportionation and self-sorting in molecular encapsulation
    Proceedings of the National Academy of Sciences ; 2009
    In:  Proceedings of the National Academy of Sciences Vol. 106, No. 26 ( 2009-06-30), p. 10430-10434
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 106, No. 26 ( 2009-06-30), p. 10430-10434
    Abstract: Self-assembled capsules are nanoscale structures made up of multiple synthetic subunits held together by weak intermolecular forces. They act as host structures that can completely surround small molecule guests of the appropriate size, shape and chemical surface. Like their biological counterparts, multimeric enzymes and receptors, the subunits of the capsules are generally identical, and lead to homomeric assemblies of high symmetry. In both biological and synthetic systems small variations in structures are tolerated and lead to heteromeric assemblies with slightly different recognition properties. The synthetic capsules are dynamic, with lifetimes from milliseconds to hours, and allow the direct spectroscopic observation of smaller molecules inside, under ambient conditions at equilibrium in solution. We report here the assembly of hybrid capsules made up of 2 very different structures, both capable of forming their own homomeric capsules through hydrogen bonding. These hybrids exhibit host properties that differ markedly from the parent capsules, and suggest that other capsules may emerge from seemingly unrelated modules that have curved surfaces and are rich in hydrogen bonding capabilities.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0809903106
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2009
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    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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