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A cellular automata computer model for the interactions between two plant species of different growth forms-the lime hairgrass Deschampsia caespitosa (L.) P. Beauv., a sod cereal, and the moneywort Lysimachia nummularia L., a ground creeping perennial herb-is considered. Computer experiments on the self maintenance of the populations of each species against the background of a gradual increase in the share of randomly eliminated individuals, coexistence of the populations of two species, and the effect of the phy togenous field have been conducted. As has been shown, all the studied factors determine the number of indi viduals and self sustainability of the simulated populations by the degree of their impact. The limits of action have been determined for individual factors; within these limits, the specific features in plant reproduction and dispersal provide sustainable coexistence of the simulated populations. It has been demonstrated that the constructed model allows for studying the long term developmental dynamics of the plants belonging to the selected growth forms.

A model of rhizosphere priming effect under impact of root exudate input into rhizosphere soil was developed as an important process of the plant-soil interaction. The model was based on the concept of nitrogen (N) mining, compensating for the N scarcity in exudates for microbial growth by accelerating SOM mineralisation. In the model, N deficiency for microbial growth is covered (“mined”) by the increased SOM mineralisation depending on the C:N ratio of the soil and exudates. The new aspect in the model is a food web procedure, which calculates soil fauna feeding on microorganisms, the return of faunal by-products to SOM and mineral N production for root uptake. The model verification demonstrated similar magnitude of the priming effect in simulations as in the published experimental data. Model testing revealed high sensitivity of the simulation results to N content in exudates. Simulated CO2 emission from the priming can reach 10–40% of CO2 emission from the whole Ah horizon of boreal forest soil depending on root exudation rates. This modeling approach with including food web activity allows quantifying wider aspects of the priming effect functioning including ecologically important available N production.

The involvement of periostin in Th2-dependent allergic inflammation has been documented. However, the significance of periostin as a biomarker of local allergic inflammation in the nasal mucosa (NM) of patients with atopic bronchial asthma (BA) and allergic rhinitis (AR) is yet to be determined. The aim of the study was to determine the presence of periostin and evaluate its role as a non-invasive marker of allergic inflammation in the nasal secretions of children with atopic BA and AR. Materials and Methods. In 43 patients aged 4–17 years with atopic BA and AR, the NM was examined using nasal video-endoscopy and (if indicated) computed tomography; the amount of periostin in the nasal secretion was determined by the enzyme immunoassay. Results. Exacerbation of AR was accompanied by a statistically significant increase in the level of periostin in the nasal secretion: up to 0.84 [0.06; 48.79] ng/mg, whereas in remission, that was 0.13 [0.00; 0.36] ng/mg; p=0.04. This value increased progressively as the severity of AR increased from 0.16 [0.00; 0.36] ng/mg in the mild course to 0.20 [0.00; 9.03] ng/mg in AR of moderate severity, and to 10.70 [0.56; 769.20] ng/mg in most severe cases; p=0.048. Hypertrophy or polyposis of the nasal and/or paranasal mucosa was detected in 34.9% (15/43) of the examined patients. The concentration of periostin in the nasal secretion was lower in children without NM hypertrophy: 0.18 [0.001; 4.30] ng/mg vs 0.78 [0.13; 162.10] ng/mg in patients with NM hypertrophy; the differences were close to statistically significant: p=0.051. The level of nasal periostin depended on the clinical form of hypertrophy in the sinonasal mucosa, reaching 0.17 [0.00; 0.32] ng/mg in children with polyposis hyperplasia of NM and 21.6 [10.70; 1516.80] ng/mg — with hypertrophy of the NM in the medial surface of the concha; p=0.02. Conclusion. Exacerbation and increased severity of AR in patients with atopic BA are accompanied by an increased level of periostin in the nasal secretion. This allows us to consider the level of nasal periostin as a biomarker of local allergic inflammation in the NM of patients with atopic BA combined with AR. Hypertrophic changes in the sinonasal mucosa are generally accompanied by an increased level of nasal periostin; specifically, this level significantly depends on the clinical form of mucous membrane hypertrophy and requires additional studies.