Antigen-induced in vitro lymphocyte blastogenesis in the rabbit: a T-cell response.

In vitro lymphocyte stimulation of sensitized rabbit lymphocytes to specific antigen (ovalbumin) was found to depend on thymic-dependent lymphocytes. This conclusion is based on an enhanced response upon enrichment with T lymphocytes by passage of lymphocytes through nylon wool, and on the elimination of the response after treatment of lymphocytes with complement and an antiserum to rabbit thymus cells prepared in a goat. Specificity of the antiserum was demonstrated by elimination of in vitro T-cell function and retention of in vitro B-cell functions.     

RNAlyzer—novel approach for quality analysis of RNA structural models

The continuously increasing amount of RNA sequence and experimentally determined 3D structure data drives the development of computational methods supporting exploration of these data. Contemporary functional analysis of RNA molecules, such as ribozymes or riboswitches, covers various issues, among which tertiary structure modeling becomes more and more important. A growing number of tools to model and predict RNA structure calls for an evaluation of these tools and the quality of outcomes their produce. Thus, the development of reliable methods designed to meet this need is relevant in the context of RNA tertiary structure analysis and can highly influence the quality and usefulness of RNA tertiary structure prediction in the nearest future. Here, we present RNAlyzer—a computational method for comparison of RNA 3D models with the reference structure and for discrimination between the correct and incorrect models. Our approach is based on the idea of local neighborhood, defined as a set of atoms included in the sphere centered around a user-defined atom. A unique feature of the RNAlyzer is the simultaneous visualization of the model-reference structure distance at different levels of detail, from the individual residues to the entire molecules.     

The role of pluripotent embryonic-like stem cells residing in adult tissues in regeneration and longevity

From the point of view of regenerative potential, the most important cells are pluripotent stem cells (PSCs). Such cells must fulfill certain in vitro as well as in vivo criteria that have been established by work with PSCs isolated from embryos, which are known as embryonic stem cells (ESCs). According to these criteria, pluripotent stem cells should: (i) give rise to cells from all three germ layers, (ii) complete blastocyst development, and (iii) form teratomas after inoculation into experimental animals. Unfortunately, in contrast to immortalized embryonic ESC lines or induced PSCs (iPSCs), these last two criteria have thus far not been obtained in a reproducible manner for any potential PSC candidates isolated from adult tissues. There are two possible explanations for this failure. The first is that PSCs isolated from adult tissues are not fully pluripotent; the second is that there are some physiological mechanisms involved in keeping these cells quiescent in adult tissues that preclude their "unleashed proliferation", thereby avoiding the risk of teratoma formation. In this review we present an evidence that adult tissues contain remnants from development; a population of PSCs that is deposited in various organs as a backup for primitive stem cells, plays a role in rejuvenation of the pool of more differentiated tissue-committed stem cells (TCSCs), and is involved in organ regeneration. These cells share several markers with epiblast/germ line cells and have been named very small embryonic-like stem cells (VSELs). We suggest that, on one hand, VSELs maintain mammalian life span but, on the other hand, they may give rise to several malignancies if they mutate. We provide an evidence that the quiescent state of these cells in adult tissues, which prevents teratoma formation, is the result of epigenetic changes in some of the imprinted genes.     

Pannexin-1 channel “fuels” by releasing ATP from bone marrow cells a state of sterile inflammation required for optimal mobilization and homing of hematopoietic stem cells

An efficient harvest of hematopoietic stem/progenitor cells (HSPCs) after pharmacological mobilization from the bone marrow (BM) into peripheral blood (PB) and subsequent proper homing and engraftment of these cells are crucial for clinical outcomes from hematopoietic transplants. Since extracellular adenosine triphosphate (eATP) plays an important role in both processes as an activator of sterile inflammation in the bone marrow microenvironment, we focused on the role of Pannexin-1 channel in the secretion of ATP to trigger both egress of HSPCs out of BM into PB as well as in reverse process that is their homing to BM niches after transplantation into myeloablated recipient. We employed a specific blocking peptide against Pannexin-1 channel and noticed decreased mobilization efficiency of HSPCs as well as other types of BM-residing stem cells including mesenchymal stroma cells (MSCs), endothelial progenitors (EPCs), and very small embryonic-like stem cells (VSELs). To explain better a role of Pannexin-1, we report that eATP activated Nlrp3 inflammasome in Gr-1⁺ and CD11b⁺ cells enriched for granulocytes and monocytes. This led to release of danger-associated molecular pattern molecules (DAMPs) and mitochondrial DNA (miDNA) that activate complement cascade (ComC) required for optimal egress of HSPCs from BM. On the other hand, Pannexin-1 channel blockage in transplant recipient mice leads to a defect in homing and engraftment of HSPCs. Based on this, Pannexin-1 channel as a source of eATP plays an important role in HSPCs trafficking.

     

The protection,stabilization and reactivation of estradiol receptors in human myometrial cytosol

Protection of estradiol receptor binding sites in human mymetrial cytosol is achieved though the agency of dithiothreitol (Cleland's reagent) (lmM) at 4°C and ? 20°C storage temperatures. Prolonged storage of cytosol at 4° C without the protective reagent results in substantial loss of binding activity. This is partially restored after Cleland's reagent (lmM) addition. However, cytosol inactivated by heating at 60°C for 30 min cannot be reconstituted in this way.     

The effect of different carbon and nitrogen sources on the activity of glutamine synthetase and glutamate dehydrogenase in lupine embryonic axes

Embryos of yellow lupine ( Lupinus luteus L. cv. Jantar), deprived of cotyledons, were incubated for 72 h in media containing various combinations of saccharose, ammonia, nitrate, glutamine and asparagine. Induction of glutamine synthetase (GS) was observed in embryos in media containing saccharose while the activity of this enzyme was inhibited by glutamine, asparagine and ammonia in the absence of sugar. The above mentioned nutritional factors had an opposite effect on the activity of glutamate dehydrogenase (GDH). Changes in glutamate dehydrogenase activity were preceded by reverse changes in the activity of glutamine synthetase. The possibility of GDH repression by GS in lupine embryos is discussed.