4 documentos corresponden a la consulta.
Palabras contadas: lactone: 4
Comin, M.J. - Pellegrinet, S.C. - Rodriguez, J.B.
Arkivoc 2005;2005(12):205-213
2005
Temas: 6-oxabicyclo[3.1.0]hexane - Ampullariella regularis - Carbocyclic nucleosides - Conformationally locked nucleosides - Neplanocin B
Descripción: (+)-Neplanocin B ((+)-5), the unnatural isomer of a minor component of the neplanocin family of antibiotics was enantioselectively synthesized starting from D-ribono-1,4-lactone. This synthetic strategy employed (+)-9-[(1R, 2R, 5S)-5-Benzyloxy-3-(benzyloxy)methyl-2-hydroxycyclopent-3-en-1-yl] -6-chloropurine (compound 7) as an advanced synthetic intermediate. ©ARKAT.
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Cirigliano, A.M. - Veleiro, A.S. - Oberti, J.C. - Burton, G.
Molecules 2000;5(3):441-442
2000
Temas: jaborosa odonelliana extract - plant extract - unclassified drug - withanolide - animal cell - antineoplastic activity - carbon nuclear magnetic resonance - conference paper - controlled study - jaborosa odonelliana
Descripción: From whole Jaborosa odonelliana plants four new withanolides containing a spiranic lactone in the side chain, were isolated and their structures elucidated by spectroscopic methods.
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Bruttomesso, A.C. - Gros, E.G.
Molecules 2000;5(3):564-565
2000
Temas: (20) 3beta,16beta dihydroxy 5 pregnen 20,16 carbolactone - 3beta hydroxy 5 androsterone - alkaloid derivative - androsterone - diosgenin - hydroxyl group - lactone - sapogenin - steroid - unclassified drug
Descripción: Diosgeninlactone (1), a natural product from Solanum vespertilio, was stereo-selectively synthesized in high yield from 3β-hydroxy-5-androstene.
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Edwards, A. - Frederix, M. - Wisniewski-Dyé, F. - Jones, J. - Zorreguieta, A. - Allan Downie, J.
J. Bacteriol. 2009;191(9):3059-3067
2009
Temas: exopolysaccharide - glucan synthase - n acylhomoserine lactone - protein - regulator protein - regulatory protein Cin - regulatory protein CinI - regulatory protein CinS - regulatory protein ExpR - regulatory protein plyB
Descripción: To understand how the Rhizobium leguminosarum rail-raiR quorum-sensing system is regulated, we identified mutants with decreased levels of RaiI-made N-acyl homoserine lactones (AHLs). A LuxR-type regulator, ExpR, is required for raiR expression, and RaiR is required to induce rail. Since raiR (and rail) expression is also reduced in cinI and cinR quorum-sensing mutants, we thought CinI-made AHLs may activate ExpR to induce raiR. However, added CinI-made AHLs did not induce raiR expression in a cinI mutant. The reduced raiR expression in cinI and cinR mutants was due to lack of expression of cinS immediately downstream of cinI. cinS encodes a 67-residue protein, translationally coupled to CinI, and cinS acts downstream of expR for raiR induction. Cloned cinS in R. leguminosarum caused an unusual collapse of colony structure, and this was delayed by mutation of expR. The phenotype looked like a loss of exopolysaccharide (EPS) integrity; mutations in cinI, cinR, cinS, and expR all reduced expression of plyB, encoding an EPS glycanase, and mutation of plyB abolished the effect of cloned cinS on colony morphology. We conclude that CinS and ExpR act to increase PlyB levels, thereby influencing the bacterial surface. CinS is conserved in other rhizobia, including Rhizobium etli; the previously observed effect of cinI and cinR mutations decreasing swarming in that strain is primarily due to a lack of CinS rather than a lack of CinI-made AHL. We conclude that CinS mediates quorum-sensing regulation because it is coregulated with an AHL synthase and demonstrate that its regulatory effects can occur in the absence of AHLs. Copyright © 2009, American Society for Microbiology.
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