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Host-associated microbial communities play important roles in wildlife health, but these dynamics can be influenced by environmental factors. Urbanization has numerous effects on wildlife; however, the degree to which wildlife-associated bacterial communities and potential bacterial pathogens vary across urban–rural/native habitat gradients remains largely unknown. We used 16S rRNA gene amplicon sequencing to examine bacterial communities found on Mountain Chickadee (Poecile gambeli) feathers and nests in urban and rural habitats. The feathers and nests in urban and rural sites had similar abundances of major bacterial phyla and dominant genera with pathogenic members. However, richness of bacterial communities and potential pathogens on birds were higher in urban habitats, and potential pathogens accounted for some of the differences in bacterial occurrence between urban and rural environments. We predicted habitat using potential pathogen occurrence with a 90% success rate for feather bacteria, and a 72.2% success rate for nest bacteria, suggesting an influence of urban environments on the presence of potential pathogens. We additionally observed similarities in bacterial communities between nests and their occupants, suggesting bacterial transmission between them. These findings improve our understanding of the bacterial communities associated with urban wildlife and suggest that urbanization impacts the composition of wildlife-associated bacterial communities. [ABSTRACT FROM AUTHOR]

The use of rustic cattle is desirable to face challenges brought on by climate change. Maremmana (MA) and Aubrac (AU) are rustic cattle breeds that can be successfully used for sustainable production. In this study, correlations between two rearing systems (feedlot and grazing) and the rumen microbiota, the lipid composition of rumen liquor (RL), and the growth performance of MA and AU steers were investigated. Bacterial community composition was characterized by high-throughput sequencing of 16S rRNA gene amplicons, and the RL lipid composition was determined by measuring fatty acid (FA) and the dimethyl acetal profiles. The main factor influencing bacterial community composition was the cattle breed. Some bacterial groups were positively correlated to average daily weight gain for the two breeds (i.e., Rikenellaceae RC9 gut group, Fibrobacter and Succiniclasticum in the rumen of MA steers, and Succinivibrionaceae UCG-002 in the rumen of AU steers); despite this, animal performance appeared to be influenced by short chain FAs production pathways and by the presence of H2 sinks that divert the H2 to processes alternative to the methanogenesis. [ABSTRACT FROM AUTHOR]

The success of ecosystem restoration following mining could be improved through consideration of the soil microbial community, which forms the foundation of ecosystems. Through sequencing we can assess the response of the microbial community to stresses such as stockpiling, and measure community recovery. We sequenced fungal and bacterial communities associated with intact Banksia woodland reference soils and stockpiled topsoil stored for one to ten years following sand mining in Western Australia. We found that both bacterial and fungal richness declined, but that the fungal community returned to a state similar to reference soils, whereas the bacterial community did not. Notably, Bradyrhizobium was absent from 10-year soils, indicating a possible lack of inoculum available to colonize legumes that are often used for revegetation. Soil fungi and bacteria respond differently to stockpiling and key taxa such as Bradyrhizobium could be lost. In addition, changes in the bacterial community may signal a reduction in plant-available nitrogen and a shift towards more anaerobic conditions consistent with previous studies. These changes in microbial communities support previous findings of reduced plant performance on 10-year stockpiled soils and emphasize the importance of considering soil age during restoration. [ABSTRACT FROM AUTHOR]

• The microbiome of the planarian S. mediterranea consisted mainly of Betaproteobacteriales. • AgNP exposure resulted in a decrease of the genera Curvibacter and Undibacterium. • The AgNP-induced bacterial shift was more pronounced in adult organisms. • A PVP-coating had a limited effect on the planarian microbiome compared to NC-AgNPs. Silver nanoparticles (AgNPs) are widely incorporated in household, consumer and medical products. Their unintentional release via wastewaters raises concerns on their environmental impact, particularly for aquatic organisms and their associated bacterial communities. It is known that the microbiome plays an important role in its host's health and physiology, e.g. by producing essential nutrients and providing protection against pathogens. A thorough understanding of the effects of AgNPs on bacterial communities and on their interactions with the host is crucial to fully assess AgNP toxicity on aquatic organisms. Our results indicate that the microbiome of the invertebrate Schmidtea mediterranea , a freshwater planarian, is affected by AgNP exposure at the tested 10 μg/ml concentration. Using targeted amplification of the bacterial 16S rRNA gene V3–V4 region, two independent experiments on the microbiomes of adult worms revealed a consistent decrease in Betaproteobacteriales after AgNP exposure, mainly attributed to a decrease in Curvibacter and Undibacterium. Although developing tissues and organisms are known to be more sensitive to toxic compounds, three independent experiments in regenerating worms showed a less pronounced effect of AgNP exposure on the microbiome, possibly because underlying bacterial community changes during development mask the AgNP induced effect. The presence of a polyvinyl-pyrrolidone (PVP) coating did not significantly alter the outcome of the experiments compared to those with uncoated particles. The observed variation between the different experiments underlines the highly variable nature of microbiomes and emphasises the need to repeat microbiome experiments, within and between physiological states of the animal. [ABSTRACT FROM AUTHOR]