Publications by authors named "Christine Wiebe"

In this review the applications of isotopically labeled compounds are discussed and put into the context of their future impact in the life sciences. Especially discussing their use in the pharma and crop science industries to follow their fate in the environment, in vivo or in complex matrices to understand the potential harm of new chemical structures and to increase the safety of human society.

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Background: Trifluoromethyloxadiazoles (TFMOs) are selective inhibitors of class II histone deacetylases (HDACs). To date, class II HDACs have not been addressed as target enzymes by commercial fungicides.

Results: Antifungal testing of a broad variety of TFMOs against several important plant pathogens showed activity against only rusts, and especially Phakopsora pachyrhizi, the cause of Asian soybean rust.

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A library of 600 taxonomically diverse Panamanian plant extracts was screened for fungicidal, insecticidal, and herbicidal activities. A total of 19 active extracts were submitted to HPLC-based activity profiling, and extracts of Bocconia frutescens, Miconia affinis, Myrcia splendens, Combretum aff. laxum, and Erythroxylum macrophyllum were selected for the isolation of compounds.

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Functional mimetics of the sialyl Lewis(X) tetrasaccharide were prepared by the enzymatic sialylation of a 1,3-diglycosylated indole and a glycosyl azide, which was subsequently transformed into a 1,4-diglycosylated 1,2,3-triazole, by using the trans-sialidase of Trypanosoma cruzi. These compounds inhibited the binding of E-, L-, and P-selectin-coated nanoparticles to polyacrylamide-bound sialyl-Lewis(X) -containing neighboring sulfated tyrosine residues (sTyr/sLe(X) -PAA) at low or sub-millimolar concentrations. Except for E-selectin, the mimetics showed higher activities than the natural tetrasaccharide.

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The cyclocondensation of enones with aminoacetonitrile furnishes 3,4-dihydro-2H-pyrrole-2-carbonitriles which can be readily converted to 2,4-disubstituted pyrroles by microwave-induced dehydrocyanation. Alternatively, oxidation of the intermediates produces 3,5-disubstituted pyrrole-2-carbonitriles.

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Mono- and diglycosylated aromatics and heteroaromatics may serve as building blocks for the construction of metabolically stable mimetics of oligosaccharides. Methods for their preparation from monosaccharidic precursors by direct C-glycosylation, dipolar cycloaddition or Larock cyclization are described.

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The reaction of alpha,beta-unsaturated carbonyl compounds with aminoacetonitrile hydrochloride furnishes 3,5-disubstituted 3,4-dihydro-2H-pyrrole-2-carbonitriles in a one-pot reaction sequence. While these products can serve as starting materials for the preparation of polysubstituted pyrrolizidines, they are kinetically stable against the base-induced elimination of HCN. In contrast, their 2-substituted analogues obtained from alpha-substituted alpha-aminonitriles can be readily converted to the corresponding 2,3,5-trisubstituted pyrroles under microwave irradiation.

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The aromatic ketone 2,2',4,4'-tetramethoxybenzophenone has a strong absorption band between 300 and 375 nm, and its pi,pi* triplet excited-state is selectively populated in methanol. Both facts make this aromatic ketone a versatile and efficient triplet photocatalyst for the transformation of alpha-diazo carbonyl compounds into mainly the cyclopropanation product.

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In the fission yeast Schizosaccharomyces pombe, the Na+/H+ exchanger, Sod2, plays a major role in the removal of excess intracellular sodium, and its disruption results in a sodium-sensitive phenotype. We examined the subcellular distribution and dynamics of Sod2 expression in S. pombe using a sod2-GFP fusion protein under the control of an attenuated version of the inducible nmt promoter.

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The Na+/H+ exchanger is an integral membrane protein found in the plasma membrane of eukaryotic and prokaryotic cells. In eukaryotes it functions to exchange one proton for a sodium ion. In mammals it removes intracellular protons while in plants and fungal cells the plasma membrane form removes intracellular sodium in exchange for extracellular protons.

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