RESUMO
New data on the diet of the wild reindeer (Rangifer tarandus pearsoni) on the Yuzhny Island of the Novaya Zemlya archipelago in the summer are presented. The coprological method shows the predominance of vascular plants in the studied samples of reindeer feces. The selectivity of reindeer in relation to pasture habitats and forage groups of plants indicates that the area and variety of forage lands in the summer are sufficient for the reindeer and are not limiting factors for it.
Assuntos
Rena , Animais , Dieta , Estações do AnoRESUMO
Enzymatic catalysis and homogeneous catalysis offer complementary means to address synthetic challenges, both in chemistry and in biology. Despite its attractiveness, the implementation of concurrent cascade reactions that combine an organometallic catalyst with an enzyme has proven challenging because of the mutual inactivation of both catalysts. To address this, we show that incorporation of a d(6)-piano stool complex within a host protein affords an artificial transfer hydrogenase (ATHase) that is fully compatible with and complementary to natural enzymes, thus enabling efficient concurrent tandem catalysis. To illustrate the generality of the approach, the ATHase was combined with various NADH-, FAD- and haem-dependent enzymes, resulting in orthogonal redox cascades. Up to three enzymes were integrated in the cascade and combined with the ATHase with a view to achieving (i) a double stereoselective amine deracemization, (ii) a horseradish peroxidase-coupled readout of the transfer hydrogenase activity towards its genetic optimization, (iii) the formation of L-pipecolic acid from L-lysine and (iv) regeneration of NADH to promote a monooxygenase-catalysed oxyfunctionalization reaction.
