A Crosstalk between the Biorhythms and Gatekeepers of Longevity: Dual Role of Glycogen Synthase Kinase-3

Biochemistry (Moscow) - This review discusses genetic and molecular pathways that link circadian timing with metabolism, resulting in the emergence of positive and negative regulatory feedback...     

Sex hormones and cardiovascular risk in male mining workers living in the European North

Age-related decrease in blood concentration of testosterone and dehydroepiandrosterone sulfate was found in mining workers living in the European North. The correlation analysis reveals associations of both hormones with biological age and testosterone with plasma lipid profile. The age dependence of cardiovascular risk and the hormonal mechanisms of its development are discussed.     

Typification of urban habitats,with ant assemblages of Moscow city taken as an example

A typification of Moscow city habitats is undertaken, based on their consideration as mosaic of patches and using such fundamental parameters as habitat origin (soil type), floristic composition, vegetation structure, and area of the biotopes. Altogether, 11 habitat types are distinguished: lawns, agrocenoses, xerophytic and mesophytic meadows, tall weeds, boulevards, small degenerative parks, small oppressed artificial parks, landscape parks, forest parks, and technocenoses. Such a classification is primarily useful for studying ants. The present paper describes the basic structure of ant assemblages in most types of urban biocenoses. The main pool of Moscow’s ant species ranked by their occurrence is as follows: Lasius niger (87%), Myrmica rugulosa (44%), Myrmica rubra (33%), Formica cunicularia (11%), Myrmica ruginodis (10%), etc. Leaf litter removal with a rake was shown to negatively affect the numbers, biomass, and species diversity of ant communities in urban areas with trees. The most stable two-species ant community revealed in Moscow City, termed an “elementary urban community,” consists of L. niger and M. rugulosa, with the former always outnumbering the latter.     

Is it possible to prove the existence of an aging program by quantitative analysis of mortality dynamics?

Accumulation of various types of lesions in the course of aging increases an organism’s vulnerability and results in a monotonous elevation of mortality rate, irrespective of the position of a species on the evolutionary tree. Stroustrup et al. (Nature, 530, 103–107) [1] showed in 2016 that in the nematode Caenorhabditis elegans, longevity-altering factors (e.g. oxidative stress, temperature, or diet) do not change the shape of the survival curve, but either stretch or shrink it along the time axis, which the authors attributed to the existence of an “aging program”. Modification of the accelerated failure time model by Stroustrup et al. uses temporal scaling as a basic approach for distinguishing between quantitative and qualitative changes in aging dynamics. Thus we analyzed data on the effects of various longevity-increasing genetic manipulations in flies, worms, and mice and used several models to choose a theory that would best fit the experimental results. The possibility to identify the moment of switch from a mortality-governing pathway to some other pathways might be useful for testing geroprotective drugs. In this work, we discuss this and other aspects of temporal scaling.     

The choice of foraging strategy as a mechanism for the coexistence of <Emphasis Type="Italic">Myrmica</Emphasis> species (Hymenoptera,Formicidae) in a multispecific ant association

The foraging behavior and some mechanisms responsible for differentiation of ecological niches were studied in five Myrmica species that frequently coexist in nature. These species were assigned to three life forms according to the preference of litter or grass cover in the course of foraging. The group foraging of Myrmica was found to be a labile communicative system, affected by the layered distribution of species and competition with closely related species. In cases when species of the same life form shared a hunting area, or when their foraging layers overlapped by over 75%, some specific hierarchical interactions were observed: the colonies of the suppressed species changed the layer of foraging or ceased to forage in groups, collecting food instead as single predators. In most cases, the prevalence-subdominance relations between the associations studied were absent.     

Coefficient of variation of lifespan across the tree of life: Is it a signature of programmed aging?

Measurements of variation are of great importance for studying the stability of pathological phenomena and processes. For the biology of aging, it is very important not only to determine average mortality, but also to study its stability in time and the size of fluctuations that are indicated by the variation coefficient of lifespan (CV_LS). It is believed that a relatively small (～20%) value of CV_LS in humans, comparable to the coefficients of variation of other events programmed in ontogenesis (for example, menarche and menopause), indicates a relatively rigid determinism (N. S. Gavrilova et al. (2012) Biochemistry (Moscow), 77, 754-760). To assess the prevalence of this phenomenon, we studied the magnitude of CV_LS, as well as the coefficients of skewness and kurtosis in diverse representatives of the animal kingdom using data provided by the Institute for Demographic Research (O. R. Jones et al. (2014) Nature, 505, 169-173). We found that, unlike humans and laboratory animals, in most examined species the values of CV_LS are rather high, indicating heterogeneity of the lifespan in the cohorts studied. This is probably due to the large influence of background mortality, as well as the non-monotonicity of total mortality in the wild, especially at the earliest ages. One way to account for this influence is to “truncate” the data (removing the earliest and latest ages from consideration). To reveal the effect of this procedure, we proposed a new indicator, the stability coefficient of mortality dynamics, which indicates how quickly CV_LS is reduced to values that characterize a relatively homogeneous population (33%) when the data are “truncated”. Such indicators facilitate the use of the parameters of survival curves for analysis of the effects of geroprotectors, lifestyle, and other factors on lifespan, and for the quantification of relative contributions of genetic and environmental factors to the dynamics of aging in human and animal populations, including those living in the wild.     

The behavior of ants of different species during joint foraging

The interaction between ants with different levels of social and territorial organization (Formica polyctena, Myrmica rubra, M. ruginodis, M. schencki, Lasius niger, and Formica fusca) was studied in the Ugra National Park (Kaluga Prov., Russia). The behavior of ants competing for an abundant source of food (carbohydrate feeders) was analyzed. It was found that the possibility of ants coexisting in a multi-species association was ensured, in particular, by different strategies of feeding behavior. A species with effective mobilization may achieve a greater competitive success as compared to more aggressive but less effectively mobilizing ones. Species characterized by non-aggressive behavior and ineffective mobilization may ensure their biological success due to an efficient system of foraging.     

Comparative study of actinomycete communities associated with Lasius niger and Formica cunicularia ants and their nests

A comparative analysis of the abundance and biodiversity of actinomycete communities isolated from living ants Lasius niger and Formica cunicularia, as well as their anthills, has been carried out for the first time. The number of actinomycetes detected in L. niger ants is close to the number of actinomycetes in their anthills and one order is higher than that for F. cunicularia. Actinomycete communities of anthills and the intact soil are characterized by a high diversity, equitability, absence of severe dominants, and the presence of common species and differ by number and the range of species. Biodiversity of actinomycetes associated with living ants is considerably lower than in their nests and the surrounding soil and the range of actinomycetes is specific for both the species of ants.