The dynamics of the motions of Drosophila melanogaster laboratory populations correlates with the parameters of space weather

Analysis of the motions of Drosophila melanogaster laboratory populations and their relationship to the heliogeophysical parameters (the radio-wave flux at the wavelength of 10.7 cm (F10.7), Wolf numbers (W), the planetary K _p-index, an indicator of geomagnetic activity) was carried out. A significant correlation between the changes in the characteristics of solar activity (F10.7, W) and the dynamics of the motions of Drosophila was detected. The association strongly depends on the sexual structure of the Drosophila populations, which follows from the difference in the distributions of this association.

     

Molecular analysis of the diversity of nitrifying bacteria in the soils of the forest and steppe zones of European Russia

Nitrifying bacteria play a key role in the global nitrogen cycle due to their ability to convert reduced nitrogen compounds (ammonium) to oxidized ones (nitrite and nitrate). Recent investigations based on the methods of molecular ecology revealed that bacteria are responsible for nitrification in natural ecosystems. At the same time, data on the species composition of the nitrifiers in soil microbial communities are scarce. Soil samples collected in the forest and steppe areas of European Russia and the enrichment cultures of nitrifying bacteria isolated from these samples were used for molecular studies of the diversity of the amoA gene encoding the synthesis of the key enzyme of autotrophic ammonium oxidation. The nitrifying bacteria of the genera Nitrosospira and Nitrosovibrio were found in all the studied soils from natural biocenoses and agrocenoses.     

Composition of root exometabolites of the symbiotically effective pea cultivar triumph and its parental forms

The qualitative and quantitative composition of low-molecular exometabolites in roots of pea (Pisum sativum L.) was studied with a cultivar Triumph and its parental forms (a symbiotically effective variety k-8274 and a modern highly productive cv. Classic). A relationship between root exudation and the ability of cultivars to establish symbiosis was analyzed. In the early stages of plant growth, the roots of cv. Triumph exhibited low exudation of organic acids, sugars, and amino acids. The quantitative composition of organic acids in the root exudates of cv. Triumph was close to that of cv. k-8274, whereas the composition of sugars and amino acids was similar to that of cv. Classic. In the field experiment, the effect of inoculation with a mixture of rhizobium strains and mycorrhizal fungus on plant growth was more evident in cv. Triumph than in cvs. Classic and k-8274. The results suggest that the high symbiotic potential of cv. Triumph is related to exudation of pyruvic and succinic acids that were the major components of root exometabolites both in Triumph and k-8274 cultivars.     

The Temperature Sensitivity of the Processes of the Initial Stage of Microbial Decomposition of Woody Litter in Forest Soil

Biophysics - Abstract—Soil organic matter of forest ecosystems is characterized by high sensitivity to increased temperatures, which makes soil organic matter more vulnerable under the...     

Long‐term nitrous oxide fluxes in annual and perennial agricultural and unmanaged ecosystems in the upper Midwest USA

Differences in soil nitrous oxide (N₂O) fluxes among ecosystems are often difficult to evaluate and predict due to high spatial and temporal variabilities and few direct experimental comparisons. For 20 years, we measured N₂O fluxes in 11 ecosystems in southwest Michigan USA: four annual grain crops (corn–soybean–wheat rotations) managed with conventional, no‐till, reduced input, or biologically based/organic inputs; three perennial crops (alfalfa, poplar, and conifers); and four unmanaged ecosystems of different successional age including mature forest. Average N₂O emissions were higher from annual grain and N‐fixing cropping systems than from nonleguminous perennial cropping systems and were low across unmanaged ecosystems. Among annual cropping systems full‐rotation fluxes were indistinguishable from one another but rotation phase mattered. For example, those systems with cover crops and reduced fertilizer N emitted more N₂O during the corn and soybean phases, but during the wheat phase fluxes were ~40% lower. Likewise, no‐till did not differ from conventional tillage over the entire rotation but reduced emissions ~20% in the wheat phase and increased emissions 30–80% in the corn and soybean phases. Greenhouse gas intensity for the annual crops (flux per unit yield) was lowest for soybeans produced under conventional management, while for the 11 other crop × management combinations intensities were similar to one another. Among the fertilized systems, emissions ranged from 0.30 to 1.33 kg N₂O‐N ha^?1 yr^?1 and were best predicted by IPCC Tier 1 and ΔEF emission factor approaches. Annual cumulative fluxes from perennial systems were best explained by soil pools (r² = 0.72) but not so for annual crops, where management differences overrode simple correlations. Daily soil N₂O emissions were poorly predicted by any measured variables. Overall, long‐term measurements reveal lower fluxes in nonlegume perennial vegetation and, for conservatively fertilized annual crops, the overriding influence of rotation phase on annual fluxes.     

Dynamics of the fecal corticosterone content in males of red,gray-sided,and bank voles (<Emphasis Type="Italic">Myodes</Emphasis>, Rodentia,Cricetidae) upon sexual maturation

The dynamics of the corticosterone content in feces of males are analyzed in red (M. rutilis), graysided (M. rufocanus), and bank (M. glareolus) voles. The ontogenetic dynamics of the corticosterone content in feces of these species collected on the 20th and 40th days are shown to depend differently on the month of their birth. At the same time, the fecal corticosterone content is similar in males of all species that originated from litters with various sizes and shares of males in it. The fecal corticosterone content in the 40-day-old animals is related to the month of birth for all three species. The species-specific features of adrenal activity are found on the 20 and 40 days after the birth of animals. The males of the May and August generations have the highest corticosterone level in feces. The fecal corticosterone content in the red vole males also correlates with the social environs; in addition, socially isolated single males have a higher rate of maturation. The fecal corticosterone in the gray-sided vole males related to the season of start maturation and to the date of birth negatively correlates with sexual maturation. The mature males of those species are found only among the spring–early summer generation. Thus, population factors are important only for maturing males that were born in the current year. Moreover, sexual maturation at a high population density is accompanied by a smaller decrease in the adrenocortical activity.