Nitric oxide (NO) is intensively synthesized in the embryo of birds. There is evidence that NO mediates myogenesis at the embryonic stage. In this regard, it might be possible to control muscle development and meat productivity by modulating NO synthesis. Using high-precision and a highly sensitive enzymatic sensor, the authors found that it is not the rate of synthesis that correlates with meat productivity, but the rate of NO oxidation to nitrate, which occurs in the tissues of the embryo. In broilers, it is several orders of magnitude higher than in layers. This indicator is solely due to the characteristics of embryonic tissues and is allelically determined. In-ovo arginine supplementation, a source of NO, did not lead to a significant increase in its synthesis and oxidation, but occasionally increased live weight gain, which was likely associated with a deficiency of free arginine and was not directly related to the effect of nitric oxide. Exogenous NO donors were oxidized with the same intensity as endogenous donors. These compounds did not have a significant effect on growth rate. Also, a reduction of 50% in the rate of NO synthesis under the action of a NO synthase inhibitor did not affect this parameter. Thus, regulation of poultry meat productivity is possible by modulating gene expression related to embryonic NO oxidation and ensuring an optimal amino acid and energy equilibrium, rather than by promoting embryonic NO synthesis. Keywords: Nitric oxide (NO), NO donor compounds, nitrate, arginine, live weight
An efficient catalytic method of the cycloaddition to C 60 fullerene of the diazoacetates, containing substituents of diverse structures in ester groups, in the presence of a Pd based three component catalyst was developed. An influence of nature and the structure of substi tuent in the ester group on the activity of diazoacetates in the reaction with C 60 was studied. Yields of respective cycloadducts were determined.An interest in carboxy derivatives of methanofullerenes is caused by a possibility of obtaining of promising prepa rations for medicine and agriculture on their base. 1-5 However, a synthesis of these C 60 derivatives containing substituents in the ester group consists in multi stage con version of carboxymethanofullerene which results in low yields of the target products. 1,3,6-9Recently, an efficient catalytic method of cycloaddi tion of diazoacetic ester and α substituted ethyl diazoace tates to the C 60 fullerene using the three component cata lyst Pd(acac) 2 -PPh 3 -Et 3 Al (20 mol.%) was suggest ed. 10,11 As it is noted, by a ratio of the starting components of catalytic system and the nature of the substituent in α position to the diazo group of the initial diazoacetate, it is possible to definitely regulate a direction of the cycload dition and to selectively obtain both methanofullerenes and homofullerenes.In order to develop our earlier elaborated 10,11 method of the catalytic cycloaddition of the diazoacetates to the C 60 fullerene under the action of catalysts on a basis of low valent Pd complexes, as well as to investigate the in fluence of the structure of substituent in the ester group of diazoacetate on the direction and the structural selectivity of the reaction of the latters with the fullerene C 60 , we studied the cycloaddition of diazoacetates with alkyl, cycloalkyl, allyl, and steroid substituents to the fullerene C 60 catalysed by Pd(acac) 2 -PPh 3 -Et 3 Al (1 : 2 : 4) Results and DiscussionIt was earlier shown, 11 that the influence of nature and substituent structure in the α substituted ethyl diazoace tates on the selectivity of formation of homo and methano fullerenes in the reaction with C 60 is most evident when the three component catalyst Pd(acac) 2 -PPh 3 -Et 3 Al (components molar ratio is 1 : 2 : 4, respectively) is used. During the cycloaddition using the components molar ra tio of this catalytic system equal to 1 : 4 : 4, only the meth anofullerenes were formed regardless of the substituent structure in the diazo compound. Therefore, all the fol lowing experiments were carried out using the catalytic system Pd(acac) 2 -PPh 3 -Et 3 Al (1 : 2 : 4) with a purpose of more detailed study of the influence of the structure of initial diazoacetates on the composition of the cyclo adducts formed.In a reaction of isopropyl diazoacetate with the fullerene C 60 (molar ratio 5 : 1) in the presence of 20 mol.% of three component catalyst Pd(acac) 2 -PPh 3 -Et 3 Al (1 : 2 : 4) in 1,2 dichlorobenzene at 80 °C, in 1 h a mixture of [6,6] closed (1) and two stereoisomeric [5,6] open...
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