Two
non-heme iron enzymes, IsnB and AmbI3, catalyze a novel decarboxylation-assisted
olefination to produce indole vinyl isonitrile, an important building
block for many natural products. Compared to other reactions catalyzed
by this enzyme family, decarboxylation-assisted olefination represents
an attractive biosynthetic route and a mechanistically unexplored
pathway in constructing a CC bond. Using mechanistic probes,
transient state kinetics, reactive intermediate trapping, spectroscopic
characterizations, and product analysis, we propose that both IsnB
and AmbI3 initiate stereoselective olefination via a benzylic C–H
bond activation by an Fe(IV)–oxo intermediate, and the reaction
likely proceeds through a radical- or carbocation-induced decarboxylation
to complete CC bond installation.
The experiments reported in this research communication aimed to plot the expression pattern of Sirt3, a master regulator of energy metabolism and antioxidation defence, in the liver of dairy goats during perinatal period. Ten healthy dairy goats in late pregnancy were chosen, and needle biopsy was applied to collect liver samples at 1-week intervals. Protein levels of hepatic Sirt3 were analysed by western-blotting. Serum enzyme activities of manganese superoxide dismutase (Mn-SOD) and non-esterified fatty acids (NEFA) levels were measured, and their correlation with Sirt3 mRNA levels was also estimated. Compared with >3-week before parturition (BP), Sirt3 proteins were significantly reduced at 1-week after parturition (AP) and 2-week AP (P < 0·05), but increased on the day of parturition (P < 0·01). Correlation analysis revealed a positive association between hepatic Sirt3 mRNA levels and serum enzyme activity of Mn-SOD (r = 0·46), but a negative association between that and serum NEFA levels (r = -0·41). These data indicate that the decreased hepatic expression of Sirt3 might be one of the reasons that dairy goats undergo oxidative stress after parturition.
Improved experimental systems are needed to advance our understanding of how the gut microbiome influences processes of the mammalian host as well as microbial community structure and function. An approach that is receiving considerable attention is the use of animal models that harbor a stable microbiota of known composition, i.e., defined microbiota, which enables control over an otherwise highly complex and variable feature of mammalian biology.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.