Regulamentação legal de empresas públicas nos países do sistema jurídico anglo-saxão

The article provides an overview of public corporation legal regulation in the Anglo-American law. The article defines the peculiarities of legal regulation of public companies in the USA and the UK. It also identifies requirements that public companies must meet. A comparative analysis was conducted concerning the organization and the activities of public and private companies. Similarities in the legal regulation of public companies in the United States and the United Kingdom are due to the fact that the American and British legal systems have the same historical roots.El artículo proporciona una descripción general de la regulación legal de las corporaciones públicas en la ley angloamericana. El artículo define las peculiaridades de la regulación legal de las empresas públicas en los Estados Unidos y el Reino Unido. También identifica los requisitos que deben cumplir las empresas públicas. Se realizó un análisis comparativo sobre la organización y las actividades de las empresas públicas y privadas. Las similitudes en la regulación legal de las empresas públicas en los Estados Unidos y el Reino Unido se deben al hecho de que los sistemas legales estadounidense y británico tienen las mismas raíces históricas.O artigo fornece uma visão geral da regulamentação legal de empresas públicas na lei anglo-americana. O artigo define as peculiaridades da regulamentação legal de empresas públicas nos EUA e no Reino Unido. Ele também identifica os requisitos que as empresas públicas devem atender. Uma análise comparativa foi realizada sobre a organização e as atividades de empresas públicas e privadas. As semelhanças na regulamentação legal das empresas públicas nos Estados Unidos e no Reino Unido devem-se ao fato de que os sistemas jurídicos americano e britânico têm as mesmas raízes históricas

Interaction between differentiating cell- and niche-derived signals in hematopoietic progenitor maintenance

Maintenance of a hematopoietic progenitor population requires extensive interaction with cells within a microenvironment or niche. In the Drosophila hematopoietic organ, niche-derived Hedgehog signaling maintains the progenitor population. Here, we show that the hematopoietic progenitors also require a signal mediated by Adenosine deaminase growth factor A (Adgf-A) arising from differentiating cells that regulates extracellular levels of adenosine. The adenosine signal opposes the effects of Hedgehog signaling within the hematopoietic progenitor cells and the magnitude of the adenosine signal is kept in check by the level of Adgf-A secreted from differentiating cells. Our findings reveal signals arising from differentiating cells that are required for maintaining progenitor cell quiescence and that function with the niche-derived signal in maintaining the progenitor state. Similar homeostatic mechanisms are likely to be utilized in other systems that maintain relatively large numbers of progenitors that are not all in direct contact with the cells of the niche

Tryptophan Hydroxylase-2-Mediated Serotonin Biosynthesis Suppresses Cell Reprogramming into Pluripotent State

The monoamine neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) has important functions both in the neural system and during embryonic development in mammals. In this study, we set out to investigate whether and how endogenous serotonin affects reprogramming to pluripotency. As serotonin is synthesized from tryptophan by the rate limiting enzymes tryptophan hydroxylase-1 and -2 (TPH1 and TPH2), we have assessed the reprogramming of TPH1- and/or TPH2-deficient mouse embryonic fibroblasts (MEFs) to induced pluripotent stem cells (iPSCs). The reprogramming of the double mutant MEFs showed a dramatic increase in the efficiency of iPSC generation. In contrast, ectopic expression of TPH2 alone or in conjunction with TPH1 reverted the rate of reprogramming of the double mutant MEFs to the wild-type level and besides, TPH2 overexpression significantly suppressed reprogramming of wild-type MEFs. Our data thus suggest a negative role of serotonin biosynthesis in the reprogramming of somatic cells to a pluripotent state

Prospects for the use of solar energy to accelerate the hardening of concrete in the construction of monolithic structures in Russia

This article addresses the issue of solving the problem of using the solar energy, that allows decreasing of the unit costs, or even avoiding using of the traditional energy resources for performance of the concrete in the southern regions of Russian. Researches that were carried out allow developing more contemporary methods of monolithic construction’s concrete curing. Various types of methods of solar energy using in case to produce precast concrete or reinforced concrete items found vast distribution and implementation in construction industry

Dual Mode of Mitochondrial ROS Action during Reprogramming to Pluripotency

Essential changes in cell metabolism and redox signaling occur during the reprogramming of somatic cells into induced pluripotent stem cells (iPSCs). In this paper, using genetic and pharmacological approaches, we have investigated the role of electron transport chain (ETC) complex-I (CI) of mitochondria in the process of cell reprogramming to pluripotency. Knockdown of NADH-ubiquinone oxidoreductase core subunits S1 (Ndufs1) or subunit B10 (Ndufb10) of the CI or inhibition of this complex with rotenone during mouse embryonic fibroblast (MEF) reprogramming resulted in a significantly decreased number of induced pluripotent stem cells (iPSCs). We have found that mitochondria and ROS levels due course of the reprogramming tightly correlate with each other, both reaching peak by day 3 and significantly declining by day 10 of the process. The transient augmentation of mitochondrial reactive oxygen species (ROS) could be attenuated by antioxidant treatment, which ameliorated overall reprogramming. However, ROS scavenging after day 3 or during the entire course of reprogramming was suppressive for iPSC formation. The ROS scavenging within the CI-deficient iPSC-precursors did not improve, but further suppressed the reprogramming. Our data therefore point to distinct modes of mitochondrial ROS action during the early versus mid and late stages of reprogramming. The data further substantiate the paradigm that balanced levels of oxidative phosphorylation have to be maintained on the route to pluripotency

Transfer of Synthetic Human Chromosome into Human Induced Pluripotent Stem Cells for Biomedical Applications

AlphoidtetO-type human artificial chromosome (HAC) has been recently synthetized as a novel class of gene delivery vectors for induced pluripotent stem cell (iPSC)-based tissue replacement therapeutic approach. This HAC vector was designed to deliver copies of genes into patients with genetic diseases caused by the loss of a particular gene function. The alphoidtetO-HAC vector has been successfully transferred into murine embryonic stem cells (ESCs) and maintained stably as an independent chromosome during the proliferation and differentiation of these cells. Human ESCs and iPSCs have significant differences in culturing conditions and pluripotency state in comparison with the murine naïve-type ESCs and iPSCs. To date, transferring alphoidtetO-HAC vector into human iPSCs (hiPSCs) remains a challenging task. In this study, we performed the microcell-mediated chromosome transfer (MMCT) of alphoidtetO-HAC expressing the green fluorescent protein into newly generated hiPSCs. We used a recently modified MMCT method that employs an envelope protein of amphotropic murine leukemia virus as a targeting cell fusion agent. Our data provide evidence that a totally artificial vector, alphoidtetO-HAC, can be transferred and maintained in human iPSCs as an independent autonomous chromosome without affecting pluripotent properties of the cells. These data also open new perspectives for implementing alphoidtetO-HAC as a gene therapy tool in future biomedical applications

Modeling Reorientation Dynamics of Electrically Assisted Light-Induced Gliding of Nematic Liquid-Crystal Easy Axis

The phenomenological torque balance model previously introduced to describe the electrically assisted light-induced gliding is generalized to study the reorientation dynamics of the nematic liquid crystal easy axis at photoaligned azo-dye films under the combined action of in-plane electric field and reorienting UV light linearly polarized at varying polarization azimuth, phi(p). We systematically examine the general properties of the torque balance model by performing analysising the bifurcations of equilibria at different values of the polarization azimuth and apply for the model to interpret the experimental results. These involve observation of the pronounced purely photoinduced reorientation at phi(p) not equal 0, as opposed to the case where the light polarization vector is parallel to the initial easy axis (phi(p) = 0), and the reorientation is almost entirely suppressed. In the regions between electrodes with nonzero electric field, the effects described by the model are that (a) the dynamics of reorientation slows down with phi(p) and (b) the sense of easy axis rotation is independent of the sign of phi(p)