Microglia and neurons in the hippocampus of migratory sandpipers

The semipalmated sandpiper Calidris pusilla and the spotted sandpiper Actitis macularia are long- and short-distance migrants, respectively. C. pusilla breeds in the sub-arctic and mid-arctic tundra of Canada and Alaska and winters on the north and east coasts of South America. A. macularia breeds in a broad distribution across most of North America from the treeline to the southern United States. It winters in the southern United States, and Central and South America. The autumn migration route of C. pusilla includes a non-stop flight over the Atlantic Ocean, whereas autumn route of A. macularia is largely over land. Because of this difference in their migratory paths and the visuo-spatial recognition tasks involved, we hypothesized that hippocampal volume and neuronal and glial numbers would differ between these two species. A. macularia did not differ from C. pusilla in the total number of hippocampal neurons, but the species had a larger hippocampal formation and more hippocampal microglia. It remains to be investigated whether these differences indicate interspecies differences or neural specializations associated with different strategies of orientation and navigation.

Characterization of the microbial community in a lotic environment to assess the effect of pollution on nitrifying and potentially pathogenic bacteria / Caracterização da comunidade microbiana em um ambiente lótico para acessar o efeito da poluição em bactérias nitrificantes e potencialmente patogênicas

This study aimed to investigate microbes involved in the nitrogen cycle and potentially pathogenic bacteria from urban and rural sites of the São Pedro stream. Water samples were collected from two sites. A seasonal survey of bacterial abundance was conducted. The dissolved nutrient content was analysed. PCR and FISH analysis were performed to identify and quantify microbes involved in the nitrogen cycle and potentially pathogenic bacteria. The seasonal survey revealed that the bacterial abundance was similar along the year on the rural area but varied on the urban site. Higher concentration of dissolved nutrients in the urban area indicated a eutrophic system. Considering the nitrifying microbes, the genus Nitrobacter was found, especially in the urban area, and may act as the principal bacteria in converting nitrite into nitrate at this site. The molecular markers napA, amoA, and nfrA were more accumulated at the urban site, justifying the higher content of nutrients metabolised by these enzymes. Finally, high intensity of amplicons from Enterococcus, Streptococcus, Bacteroides/Prevotella/Porphyromonas, Salmonella, S. aureus, P. aeruginosa and the diarrheagenic lineages of E. coli were observed at the urban site. These results indicate a change in the structure of the microbial community imposed by anthrophic actions. The incidence of pathogenic bacteria in aquatic environments is of particular importance to public health, emphasising the need for sewage treatment to minimise the environmental impacts associated with urbanisation.

Este estudo objetivou investigar os micro-organismos envolvidos no ciclo do nitrogênio e bactérias potencialmente patogênicas das áreas urbanas e rurais do Córrego São Pedro. Amostras de água foram coletadas dos dois locais. Um levantamento sazonal da densidade bacteriana foi realizado. O teor de nutriente dissolvido foi avaliado. As técnicas de PCR e FISH foram realizadas para identificar e quantificar os micro-organismos envolvidos no ciclo do nitrogênio e bactérias potencialmente patogênicas. O levantamento sazonal revelou que a abundância bacteriana foi semelhante ao longo do ano na área rural, porém variou na região urbana. Altas concentrações de nutrientes dissolvidos na área urbana indicaram este como um sistema eutrófico. Considerando os micro-organismos nitrificantes, o gênero Nitrobacter foi encontrado, especialmente na região urbana, e pode estar atuando como a principal bactéria convertendo nitrito em nitrato nessa área. Os marcadores moleculares napA, amoA, e nfrA foram mais acumulados na área urbana, justificando o alto teor dos nutrientes metabolizados por essas enzimas. Finalmente, alta intensidade de amplicons para Enterococcus, Streptococcus, Bacteroides/Prevotella/Porphyromonas, Salmonella, S. aureus, P. aeruginosa e linhagens diarreagênicas de E. coli foram observados na área urbana. Estes resultados indicaram uma mudança na estrutura da comunidade microbiana imposta pelas ações antropogênicas. A incidência de bactérias patogênicas em ambientes aquáticos é de particular importância para a saúde pública, enfatizando a necessidade de tratamentos de esgoto para minimizar os impactos ambientais associados com a urbanização.