Aging Chart: a community resource for rapid exploratory pathway analysis of age-related processes.

Aging research is a multi-disciplinary field encompassing knowledge from many areas of basic, applied and clinical research. Age-related processes occur on molecular, cellular, tissue, organ, system, organismal and even psychological levels, trigger the onset of multiple debilitating diseases and lead to a loss of function, and there is a need for a unified knowledge repository designed to track, analyze and visualize the cause and effect relationships and interactions between the many elements and processes on all levels. Aging Chart (http://agingchart.org/) is a new, community-curated collection of aging pathways and knowledge that provides a platform for rapid exploratory analysis. Building on an initial content base constructed by a team of experts from peer-reviewed literature, users can integrate new data into biological pathway diagrams for a visible, intuitive, top-down framework of aging processes that fosters knowledge-building and collaboration. As the body of knowledge in aging research is rapidly increasing, an open visual encyclopedia of aging processes will be useful to both the new entrants and experts in the field.

Can xenon in water inhibit ice growth? Molecular dynamics of phase transitions in water-Xe system.

Motivated by recent experiments showing the promise of noble gases as cryoprotectants, we perform molecular dynamics modeling of phase transitions in water with xenon under cooling. We follow the structure and dynamics of xenon water solution as a function of temperature. Homogeneous nucleation of clathrate hydrate phase is observed and characterized. As the temperature is further reduced we observe hints of dissociation of clathrate due to stronger hydrophobic hydration, pointing towards a possible instability of clathrate at cryogenic temperatures and conversion to an amorphous phase comprised of "xenon + hydration shell" Xe·(H2O)21.5 clusters. Simulations of ice-xenon solution interface in equilibrium and during ice growth reveal the effects of xenon on the ice-liquid interface, where adsorbed xenon causes roughening of ice surface but does not preferentially form clathrate. These results provide evidence against the ice-blocker mechanism of xenon cryoprotection.

Accelerated aging versus rejuvenation of the immune system in heterochronic parabiosis.

The emergence of immune disorders in aging is explained by many factors, including thymus dysfunction, decrease in the proportion and function of naïve T cells, and so forth. There are several approaches to preventing these changes, such as thymus rejuvenation, stem cells recovery, modulation of hormone production, and others. Our investigations of heterochronic parabiosis have shown that benefits of a young immune system, e.g., actively working thymus and regular migration of young hematopoietic stem cells between parabiotic partners, appeared unable to restore the immune system of the old partner. At the same time, we have established a progressive immune impairment in the young heterochronic partners. The mechanism of age changes in the immune system in this model, which may lead to reduced life expectancy, has not been fully understood. The first age-related manifestation in the young partners observed 3 weeks after the surgery was a dramatic increase of CD8(+)44(+) cells population in the spleen. A detailed analysis of further changes revealed a progressive decline of most immunological functions observable for up to 3 months after the surgery. This article reviews possible mechanisms of induction of age-related changes in the immune system of young heterochronic partners. The data obtained suggest the existence of certain factors in the old organisms that trigger aging, thus preventing the rejuvenation process.