Extracts and melanins from Inonotus obliquus are widely used in medicine due to their high antioxidant properties. This study is dedicated to define the influence of the physicochemical and antioxidant properties of Inonotus obliquus melanins and their bifidogenic effects on Bifidobacterium bifidum 1 and Bifidobacterium animalis subsp. lactis. For this purpose, melanins precipitated from Inonotus obliquus aqueous extracts, obtained by a few methods, and separated melanin fractions by organic solvents were used. For the melanin physicochemical properties analysis spectrophotometry, electron paramagnetic resonance (EPR) spectroscopy and dynamic light scattering methods were applied. Melanins and their fractions difference in particle size and charge, antioxidant properties, and redox potential were revealed. It was shown that the redox potential, the size of melanin particles and the z-potential had maximum influence on bifidobacteria growth. The greatest activating effect on bifidobacteria was established by using melanin isolated from aqueous microwave extracts in concentrations of 10−13, 10−10, 10−5 g/cm3. The use of this melanin with antioxidant activity 0.67 ± 0.06 mg/g (expressed as ascorbic acid equivalent), and with redox potential −5.51 ± 2.22 mV as a prebiotic allowed the growth of Bifidobacterium bifidum 1 s to increase by 1.4 times in comparison with ascorbic acid by 24 h of cultivation.

The short 5'-terminal oligopyrimidine tract (TOP) of 5' UTRs is a well-known regulatory sequence motif of mRNAs that are subject to growth-dependent translation. Specifically, translation of TOP mRNAs is regulated by the mTOR signaling pathway that is involved in cell proliferation, cancer development and aging. High throughput data permit detailed study of specific features of the mRNA TOP motif and its DNA origins at transcription start sites (TSS). Recently, ribosome profiling was used to identify mRNA targets of the mTOR pathway in PC3 cells. A novel pyrimidine-rich translational element (PRTE) was reported to play a key role without positional preferences within the 5' UTRs, unlike 5' TOP, which are strictly located at the 5' ends. In this study, we couple recently reported ribosome profiling data on the mTOR mRNA targets with the annotation of TSS obtained by HeliScopeCAGE. We confirm the canonical TOP and strong positional preferences of respective oligopyrimidine tracts (OP) straddling the experimentally validated TSS regions at the DNA level. Such OP localization ensures that transcription from OP segments creates the 5'-terminal TOP in the corresponding mRNAs. We demonstrate that OP are not overrepresented in downstream regions of 5' UTRs of mTOR targets. Finally, we highlight several mTOR target genes with broad and multimodal TSS spanning dozens of nucleotides that are only partically covered with an OP. Therefore, in such cases only a fraction of all produced mRNAs carry a TOP regulatory motif and, thus, respond to mTOR via TOP mechanism. We hypothesize that the interplay between transcription and translation may play a crucial role in the regulation of the mTOR response.

Систематизированы данные по химическому составу веществ тритерпеновой и стероидной природы, выделенных из чаги, как выращенной в условиях искусственной культуры, так и произрастающей в природе. Приведены сведения по биологической активности экстрактов из чаги и этих соединений в отношении различных линий клеток рака in vitro и in vivо. Проведённый анализ позволил выявить определенные закономерности в эффективности подавления роста различных линий клеток. Установлено, что наибольшей активностью обладают тритерпеновые соединения, содержащие ОН-группу при С-22 и ненасыщенную связь в боковой цепи.Ключевые слова: чага, тритерпеновые соединения, стероидные соединения, биологическая активность, in vivo, in vitro DOI 10.18097/PBMC20166204369Рисунок. Общая структурная формула тритерпенов ланостанового ряда (а) и стероидных соединений (б).

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