Significant disparities in allergy prevalence and microbiota between the young people in Finnish and Russian Karelia.

BACKGROUND: Atopic allergy has been more common among schoolchildren in Finland, as compared to Russian Karelia. These adjacent regions show one of the most contrasting socio-economical differences in the world. OBJECTIVE: We explored changes in allergy from school age to young adulthood from 2003 to 2010/2012 in these two areas. The skin and nasal microbiota were also compared. METHODS: Randomly selected children from Finnish (n = 98) and Russian Karelia (n = 82) were examined in 2003, when the children were 7-11 years of age, and again in 2010 (Finnish Karelia) and 2012 (Russian Karelia). We analysed self-reported allergy symptoms and sensitization to common allergens by serum sIgE values. The skin (volar forearm) and nasal mucosa microbiota, collected in 2012 (aged 15-20 years), identified from DNA samples, were compared with multivariate methods. RESULTS: Asthma, hay fever, atopic eczema, self-reported rhinitis, as well as atopic sensitization, were threefold to 10-fold more common in Finland, as compared to Russian Karelia. Hay fever and peanut sensitization were almost non-existent in Russia. These patterns remained throughout the 10-year follow-up. Skin microbiota, as well as bacterial and fungal communities in nasal mucosa, was contrastingly different between the populations, best characterized by the diversity and abundance of genus Acinetobacter; more abundant and diverse in Russia. Overall, diversity was significantly higher among Russian subjects (Pskin < 0.0001, Pnasal-bacteria < 0.0001 and Pnasal-fungi < 0.01). Allergic diseases were not associated with microbial diversity in Finnish subjects. CONCLUSIONS AND CLINICAL RELEVANCE: Differences in allergic phenotype, developed in early life, remain between populations. A parallel difference in the composition of skin and nasal microbiota suggests a potential underlying mechanism. Our results also suggest that high abundance and diversity of Acinetobacter might contribute to the low allergy prevalence in Russia. Implications of early-life exposure to Acinetobacter should be further investigated.

Larval growth rate is associated with the composition of the gut microbiota in the Glanville fritillary butterfly.

The rapidly increasing body of literature on commensal microbiota has revealed a large phylotypic and functional diversity of microbes associated with vertebrates and invertebrates. In insects, the gut microbiota plays a role in digestion and metabolism of the host as well as protects the host against pathogens. In the study reported here, we sampled gut microbiota of the larvae of the Glanville fritillary butterfly (Melitaea cinxia). The larvae were collected from the field or reared in the laboratory. This butterfly has two host plant species, Plantago lanceolata and Veronica spicata, and the host plant species is known from previous studies to influence larval growth rate. However, our results demonstrate that about 50 % of the variation in larval growth rate can be attributed to the effect of the gut microbial composition plus the joint effect of microbiota and the host plant species, while host plant species alone makes no significant contribution. Our results support previous studies showing that diet influences the gut microbiota but, more unexpectedly, that the composition of the gut microbiota significantly influences larval growth rate. We suggest that host plant effects on larval growth and development observed in many previous studies may be mediated via the gut microbiota. While we measured the growth rate only in laboratory-reared larvae, the similarity of the gut microbial composition between samples from field-collected and laboratory-reared larvae suggests that the results can be generalized to natural conditions.

Green areas around homes reduce atopic sensitization in children.

BACKGROUND: Western lifestyle is associated with high prevalence of allergy, asthma and other chronic inflammatory disorders. To explain this association, we tested the 'biodiversity hypothesis', which posits that reduced contact of children with environmental biodiversity, including environmental microbiota in natural habitats, has adverse consequences on the assembly of human commensal microbiota and its contribution to immune tolerance. METHODS: We analysed four study cohorts from Finland and Estonia (n = 1044) comprising children and adolescents aged 0.5-20 years. The prevalence of atopic sensitization was assessed by measuring serum IgE specific to inhalant allergens. We calculated the proportion of five land-use types--forest, agricultural land, built areas, wetlands and water bodies--in the landscape around the homes using the CORINE2006 classification. RESULTS: The cover of forest and agricultural land within 2-5 km from the home was inversely and significantly associated with atopic sensitization. This relationship was observed for children 6 years of age and older. Land-use pattern explained 20% of the variation in the relative abundance of Proteobacteria on the skin of healthy individuals, supporting the hypothesis of a strong environmental effect on the commensal microbiota. CONCLUSIONS: The amount of green environment (forest and agricultural land) around homes was inversely associated with the risk of atopic sensitization in children. The results indicate that early-life exposure to green environments is especially important. The environmental effect may be mediated via the effect of environmental microbiota on the commensal microbiota influencing immunotolerance.

Resistance to oxidative damage but not immunosuppression by organic tin compounds in natural populations of Daubenton's bats (Myotis daubentonii).

The acute toxicity of organic tin compounds (OTCs) has been studied in detail. However, due to their complex nature, very little is known about species-specific methods of accumulation and consequences for food-webs. Chironomids, on which e.g. Daubenton's bats feed, may act as vectors for the transport of organic tin compounds from aquatic to terrestrial ecosystems. Bats are prone to environmental toxins because of their longevity and their ecological role as top predators. Organic tin compounds are associated with increased formation of reactive oxygen species and associated oxidative damage as well as suppression of immune function. The present paper investigates whether the OTC, tributyltin (TBT) and its metabolite, dibutyltin (DBT), accumulate in natural populations of Daubenton's bats and whether TBT-associated effects are seen in general body condition, redox balance, redox enzyme activities, associated oxidative damage of red blood cells and complement function. We discovered the concentration of bat fur DBT correlated with local marine sediment TBT concentrations. However, we did not find a correlation between the explanatory factors, bat fur DBT and marine sediment TBT concentrations, and several physiological and physical response variables apart from complement activity. Higher DBT concentrations resulted in weaker complement activity and thus a weaker immune response. Although the observed physiological effects in the present study were not strongly correlated to butyltin concentrations in fur or sediment, the result is unique for natural populations so far and raises interesting questions for future ecotoxicological studies.

Sediment organic tin contamination promotes impoverishment of non-biting midge species communities in the Archipelago Sea, S-W Finland.

Chironomid species are a vital component in many benthic and terrestrial food webs; they have an important role in the detritus cycle, and are an important source of food for many species. We studied how tributyltin (TBT) in brackish water sediments affect the composition of chironomid species communities. Emergence traps were used at selected sites on a TBT gradient in the Archipelago Sea, S-W Finland. Increased sediment TBT concentration was associated with significant chironomid species turnover, which in turn was related to decreased species diversity (number of species and genera). However, the overall number of individuals did not decrease markedly with increasing TBT contamination. This suggests that the ecological role of chironomids in the food web may be preserved even under severe impoverishment of the chironomid community due to organic tin contamination. The increased prevalence of more TBT tolerant species can potentially lead to a transport of organic tin compounds between aquatic and terrestrial food webs. Furthermore, the reduced diversity of an ecologically influential group might lower the resistance of the entire food web to other environmental hazards and perturbations.