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  1. Article: Remote electronic control of DNA hybridization through inductive coupling to an attached metal nanocrystal antenna.

    Hamad-Schifferli, Kimberly / Schwartz, John J / Santos, Aaron T / Zhang, Shuguang / Jacobson, Joseph M

    Nature

    2002  Volume 415, Issue 6868, Page(s) 152–155

    Abstract: Increasingly detailed structural and dynamic studies are highlighting the precision with which biomolecules execute often complex tasks at the molecular scale. The efficiency and versatility of these processes have inspired many attempts to mimic or ... ...

    Abstract Increasingly detailed structural and dynamic studies are highlighting the precision with which biomolecules execute often complex tasks at the molecular scale. The efficiency and versatility of these processes have inspired many attempts to mimic or harness them. To date, biomolecules have been used to perform computational operations and actuation, to construct artificial transcriptional loops that behave like simple circuit elements and to direct the assembly of nanocrystals. Further development of these approaches requires new tools for the physical and chemical manipulation of biological systems. Biomolecular activity has been triggered optically through the use of chromophores, but direct electronic control over biomolecular 'machinery' in a specific and fully reversible manner has not yet been achieved. Here we demonstrate remote electronic control over the hybridization behaviour of DNA molecules, by inductive coupling of a radio-frequency magnetic field to a metal nanocrystal covalently linked to DNA. Inductive coupling to the nanocrystal increases the local temperature of the bound DNA, thereby inducing denaturation while leaving surrounding molecules relatively unaffected. Moreover, because dissolved biomolecules dissipate heat in less than 50 picoseconds (ref. 16), the switching is fully reversible. Inductive heating of macroscopic samples is widely used, but the present approach should allow extension of this concept to the control of hybridization and thus of a broad range of biological functions on the molecular scale.
    MeSH term(s) Crystallography ; DNA/chemistry ; Electrochemistry ; Gold/chemistry ; Magnetics ; Nanotechnology ; Nucleic Acid Conformation ; Nucleic Acid Hybridization ; Temperature
    Chemical Substances Gold (7440-57-5) ; DNA (9007-49-2)
    Language English
    Publishing date 2002-01-10
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 120714-3
    ISSN 1476-4687 ; 0028-0836
    ISSN (online) 1476-4687
    ISSN 0028-0836
    DOI 10.1038/415152a
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Normal levels of anticoagulant heparan sulfate are not essential for normal hemostasis.

    HajMohammadi, Sassan / Enjyoji, Keiichi / Princivalle, Marc / Christi, Patricia / Lech, Miroslav / Beeler, David / Rayburn, Helen / Schwartz, John J / Barzegar, Samad / de Agostini, Ariane I / Post, Mark J / Rosenberg, Robert D / Shworak, Nicholas W

    The Journal of clinical investigation

    2003  Volume 111, Issue 7, Page(s) 989–999

    Abstract: Endothelial cell production of anticoagulant heparan sulfate (HS(act)) is controlled by the Hs3st1 gene, which encodes the rate-limiting enzyme heparan sulfate 3-O-sulfotransferase-1 (3-OST-1). In vitro, HS(act) dramatically enhances the neutralization ... ...

    Abstract Endothelial cell production of anticoagulant heparan sulfate (HS(act)) is controlled by the Hs3st1 gene, which encodes the rate-limiting enzyme heparan sulfate 3-O-sulfotransferase-1 (3-OST-1). In vitro, HS(act) dramatically enhances the neutralization of coagulation proteases by antithrombin. The in vivo role of HS(act) was evaluated by generating Hs3st1(-/-) knockout mice. Hs3st1(-/-) animals were devoid of 3-OST-1 enzyme activity in plasma and tissue extracts. Nulls showed dramatic reductions in tissue levels of HS(act) but maintained wild-type levels of tissue fibrin accumulation under both normoxic and hypoxic conditions. Given that vascular HS(act) predominantly occurs in the subendothelial matrix, mice were subjected to a carotid artery injury assay in which ferric chloride administration induces de-endothelialization and occlusive thrombosis. Hs3st1(-/-) and Hs3st1(+/+) mice yielded indistinguishable occlusion times and comparable levels of thrombin.antithrombin complexes. Thus, Hs3st1(-/-) mice did not show an obvious procoagulant phenotype. Instead, Hs3st1(-/-) mice exhibited genetic background-specific lethality and intrauterine growth retardation, without evidence of a gross coagulopathy. Our results demonstrate that the 3-OST-1 enzyme produces the majority of tissue HS(act). Surprisingly, this bulk of HS(act) is not essential for normal hemostasis in mice. Instead, 3-OST-1-deficient mice exhibited unanticipated phenotypes suggesting that HS(act) or additional 3-OST-1-derived structures may serve alternate biologic roles.
    MeSH term(s) Animals ; Anticoagulants/pharmacology ; Antithrombins/metabolism ; Carotid Arteries/pathology ; Crosses, Genetic ; Endothelium, Vascular/cytology ; Endothelium, Vascular/enzymology ; Exons ; Female ; Genotype ; Hemostasis ; Heparitin Sulfate/pharmacology ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Mice, Transgenic ; Models, Genetic ; Retroviridae/genetics ; Sulfotransferases/metabolism ; Thrombin/metabolism ; Tissue Distribution
    Chemical Substances Anticoagulants ; Antithrombins ; Heparitin Sulfate (9050-30-0) ; Sulfotransferases (EC 2.8.2.-) ; heparan sulfate D-glucosaminyl 3-O-sulfotransferase (EC 2.8.2.-) ; Thrombin (EC 3.4.21.5)
    Language English
    Publishing date 2003-04-03
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 3067-3
    ISSN 1558-8238 ; 0021-9738
    ISSN (online) 1558-8238
    ISSN 0021-9738
    DOI 10.1172/JCI15809
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Ua VI Zs.184: Show issues Location:
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