30361-33-2Relevant articles and documents
Teratogenic effects of diatom metabolites on sea urchin Paracentrotus lividus embryos
Romano, Giovanna,Miralto, Antonio,Ianora, Adrianna
, p. 950 - 967 (2010)
The diatom-derived polyunsaturated aldehydes (PUAs), 2-trans,4-trans- decadienal, 2-trans,4-trans-octadienal, 2-trans,4-trans,7-octatrienal, 2-trans,4-trans-heptadienal, as well as tridecanal were tested on early and later larval development in the sea urchin Paracentrotus lividus. We also tested the effect of some of the more abundant diatom polyunsaturated fatty acids (PUFAs) on development, in particular 5,8,11,14,17-eicosapentaenoic acid (EPA), one of the main precursors of diatom PUAs, as well as 4,7,10,13,16,19- docosahexaenoic acid (DHA), 6,9,12,15-octadecatetraenoic acid (stearidonic acid), 6,9,12-octadecatrienoic acid (γ-linolenic acid) and 9,12-octadecadienoic acid (linoleic acid). PUAs blocked sea urchin cell cleavage in a dose dependent manner and with increasing chain length from C7 to C10 PUAs, with arrest occurring at 27.27 μM with heptadienal, 16.13 μM with octadienal, 11.47 μM with octatrienal and 5.26 μM with decadienal. Of the PUFAs tested, only EPA and stearidonic acid blocked cleavage, but at much higher concentrations compared to PUAs (331 μM for EPA and 181 μM for stearidonic acid). Sub-lethal concentrations of decadienal (1.32-5.26 μM) delayed development of embryos and larvae which showed various degrees of malformations depending on the concentrations tested. Sub-lethal concentrations also increased the proportion of TUNEL-positive cells indicating imminent death in embryos and larvae. Using decadienal as a model PUA, we show that this aldehyde can be detected spectrophotometrically for up to 14 days in f/2 medium.
Evidence from Raman spectroscopy that InhA, the mycobacterial enoyl reductase, modulates the conformation of the NADH cofactor to promote catalysis
Bell, Alasdair F.,Stratton, Christopher F.,Zhang, Xujie,Novichenok, Polina,Jaye, Andrew A.,Nair, Pravin A.,Parikh, Sapan,Rawat, Richa,Tonge, Peter J.
, p. 6425 - 6431 (2007)
InhA, the enoyl reductase from Mycobacterium tuberculosis, catalyzes the NADH-dependent reduction of trans-2-enoyl-ACPs. In the present work, Raman spectroscopy has been used to identify catalytically relevant changes in the conformation of the nicotinamide ring that occur when NADH binds to InhA. For 4(S)-NADD, there is an 11 cm-1 decrease in the wavenumber of the C4-D stretching band (νC-D) and a 50% decrease in the width of this band upon binding to InhA. While a similar reduction in line width is observed for the corresponding band arising from 4(R)-NADD, νC-D for this isomer increases 34 cm-1 upon binding to InhA. These changes in νC-D indicate that the nicotinamide ring adopts a bound conformation in which the 4(S)C-D bond is in a pseudoaxial orientation. Mutagenesis of F149, a conserved active site residue close to the cofactor, demonstrates that this enzyme-induced modulation in cofactor structure is directly linked to catalysis. In contrast to the wild-type enzyme, Raman spectra of NADD bound to F149A InhA resemble those of NADD in solution. Consequently, F149A is no longer able to optimally position the cofactor for hydride transfer, which correlates with the 30-fold decrease in feat and 2-fold increase in D(V/KNADH) caused by this mutation. These studies thus substantiate the proposal that hydride transfer is promoted by pseudoaxial positioning of the NADH pro-4S bond, and indicate that catalysis of substrate reduction by InhA results, in part, from correct orientation of the cofactor in the ground state.
Stereoselective Cross-Coupling of Grignard Reagents and Conjugated Dienylbromides using Iron Salts with Magnesium Alkoxides
Chourreu, Pablo,Gayon, Eric,Guerret, Olivier,Guillonneau, Lo?c,Lefèvre, Guillaume
supporting information, p. 4701 - 4706 (2021/09/10)
A convenient procedure allowing iron-catalyzed cross-coupling of alkyl or aryl Grignard reagents and conjugated dienyl bromides is reported, relying on the use of cheap and non-toxic magnesium alkoxides as sole additives. An excellent stereoselectivity is observed in the alkyl-dienyl series. This sequence has been applied to the synthesis of the sex pheromone of codling moth, illustrating its applicability for obtaining targets of industrial interest. Preliminary mechanistic studies carried out on the aryl-dienyl cross-coupling suggest that in situ generated ate homoleptic organoiron(II) species act as catalytically relevant intermediates. A modified preparative method for the realization of THF solutions of dienyl bromides as “ready-to-use” coupling partners is also discussed, circumventing the thermal instability of those derivatives.
