Project description:Fire disturbances are becoming more common, more intense, and further-reaching across the globe, with consequences for ecosystem functioning. Importantly, fire can have strong effects on the soil microbiome, including community and functional changes after fire, but surprisingly little is known regarding the role of soil fire legacy in shaping responses to recent fire. To address this gap, we conducted a manipulative field experiment administering fire across 32 soils with varying fire legacies, including combinations of 1-7 historic fires and 1-33 years since most recent fire. We analyzed soil metatranscriptomes, determining for the first time how fire and fire legacy interactively affect metabolically-active soil taxa, the microbial regulation of important carbon (C), nitrogen (N) and phosphorus (P) cycling, expression of carbohydrate-cycling enzyme pathways, and functional gene co-expression networks. Experimental fire strongly downregulated fungal activity while upregulating many bacterial and archaeal phyla. Further, fire decreased soil capacity for microbial C and N cycling and P transport, and drastically rewired functional gene co-expression. Perhaps most importantly, we highlight a novel role of soil fire legacy in regulation of microbial C, N, and P responses to recent fire. We observed a greater number of functional genes responsive to the interactive effects of fire and fire legacy than those affected solely by recent fire, indicating that many functional genes respond to fire only under certain fire legacy contexts. Therefore, without incorporating fire legacy of soils, studies will miss important ways that fire shapes microbial roles in ecosystem functioning. Finally, we showed that fire caused significant downregulation of carbon metabolism and nutrient cycling genes in microbiomes under abnormal soil fire histories, producing a novel warning for the future: human manipulation of fire legacies, either indirectly through global change-induced fire intensification or directly through fire suppression, can negatively impact soil microbiome functional responses to new fires.

Project description:Humans vary markedly in their propensity to develop asthma, despite often being exposed to similar environmental stimuli. Similarly, mouse strains vary in susceptibility to airways pathology in experimental asthma. Sensitization and aerosol challenge with ovalbumin (OVA) induces eosinophil accumulation, mucus production and airways obstruction in BALB/c and C57BL/6 mice. In contrast, CBA/Ca mice show relatively little pathology. Allergen-induced production of IL-4, IL-5, IL-10 and IFN-g was detected in all three strains, with BALB/c mice generating the highest levels of IL-4, IL-5 and IL-10. Microarray analysis was used to identify genes differentially regulated in lung tissue after OVA challenge. Differentially regulated genes in the lungs of the asthma-susceptible C57BL/6 and BALB/c strains numbered 242 and 145, respectively, whereas only 42 genes were differentially expressed in the resistant CBA/Ca strain. In C57BL/6 mice, transcripts were enriched for adhesion molecules and this was associated with high levels of eosinophil recruitment. Differentially regulated genes in the lungs of only the asthma-susceptible strains numbered 64 and several of these have not previously been associated with asthma. Many of the genes differentially regulated in the susceptible strains were enzymes involved in inflammation. Using network analysis, mRNA for the anti-apoptotic protein survivin was found to be up-regulated in the lungs following allergen challenge. Survivin mRNA and protein were also expressed at high levels in eosinophils recovered by bronchoalveolar lavage from BALB/c and C57BL/6 mice. We propose that rapid apoptosis of lung eosinophils due to low expression of survivin contributes to the limitation of pathology in CBA/Ca mice Humans vary markedly in their propensity to develop asthma, despite often being exposed to similar environmental stimuli. Similarly, mouse strains vary in susceptibility to airways pathology in experimental asthma. Sensitization and aerosol challenge with ovalbumin (OVA) induces eosinophil accumulation, mucus production and airways obstruction in BALB/c and C57BL/6 mice. In contrast, CBA/Ca mice show relatively little pathology. Allergen-induced production of IL-4, IL-5, IL-10 and IFN-g was detected in all three strains, with BALB/c mice generating the highest levels of IL-4, IL-5 and IL-10. Microarray analysis was used to identify genes differentially regulated in lung tissue after OVA challenge. Differentially regulated genes in the lungs of the asthma-susceptible C57BL/6 and BALB/c strains numbered 242 and 145, respectively, whereas only 42 genes were differentially expressed in the resistant CBA/Ca strain. In C57BL/6 mice, transcripts were enriched for adhesion molecules and this was associated with high levels of eosinophil recruitment. Differentially regulated genes in the lungs of only the asthma-susceptible strains numbered 64 and several of these have not previously been associated with asthma. Many of the genes differentially regulated in the susceptible strains were enzymes involved in inflammation. Using network analysis, mRNA for the anti-apoptotic protein survivin was found to be up-regulated in the lungs following allergen challenge. Survivin mRNA and protein were also expressed at high levels in eosinophils recovered by bronchoalveolar lavage from BALB/c and C57BL/6 mice. We propose that rapid apoptosis of lung eosinophils due to low expression of survivin contributes to the limitation of pathology in CBA/Ca mice Changes in gene expression in the lungs of 4 individual of BALB/c mice challenged with OVA were monitored using the lungs of 4 individual BALB/c mice challenged with PBS as the control. The microarray analysis was performed in quadruplicate. Changes in gene expression in the lungs of 4 individual of CBA/Ca mice challenged with OVA were monitored using the lungs of 4 individual CBA/Ca mice challenged with PBS as the control. The microarray analysis was performed in quadruplicate. Changes in gene expression in the lungs of 4 individual of BALB/c mice challenged with OVA were monitored using the lungs of 4 individual CBA/Ca mice challenged with OVA as the control. The microarray analysis was performed in quadruplicate. Twelve dual channel microarray slides were used in the overall design of this experiment.

Project description:Humans vary markedly in their propensity to develop asthma, despite often being exposed to similar environmental stimuli. Similarly, mouse strains vary in susceptibility to airways pathology in experimental asthma. Sensitization and aerosol challenge with ovalbumin (OVA) induces eosinophil accumulation, mucus production and airways obstruction in BALB/c and C57BL/6 mice. In contrast, CBA/Ca mice show relatively little pathology. Allergen-induced production of IL-4, IL-5, IL-10 and IFN-g was detected in all three strains, with BALB/c mice generating the highest levels of IL-4, IL-5 and IL-10. Microarray analysis was used to identify genes differentially regulated in lung tissue after OVA challenge. Differentially regulated genes in the lungs of the asthma-susceptible C57BL/6 and BALB/c strains numbered 242 and 145, respectively, whereas only 42 genes were differentially expressed in the resistant CBA/Ca strain. In C57BL/6 mice, transcripts were enriched for adhesion molecules and this was associated with high levels of eosinophil recruitment. Differentially regulated genes in the lungs of only the asthma-susceptible strains numbered 64 and several of these have not previously been associated with asthma. Many of the genes differentially regulated in the susceptible strains were enzymes involved in inflammation. Using network analysis, mRNA for the anti-apoptotic protein survivin was found to be up-regulated in the lungs following allergen challenge. Survivin mRNA and protein were also expressed at high levels in eosinophils recovered by bronchoalveolar lavage from BALB/c and C57BL/6 mice. We propose that rapid apoptosis of lung eosinophils due to low expression of survivin contributes to the limitation of pathology in CBA/Ca mice Humans vary markedly in their propensity to develop asthma, despite often being exposed to similar environmental stimuli. Similarly, mouse strains vary in susceptibility to airways pathology in experimental asthma. Sensitization and aerosol challenge with ovalbumin (OVA) induces eosinophil accumulation, mucus production and airways obstruction in BALB/c and C57BL/6 mice. In contrast, CBA/Ca mice show relatively little pathology. Allergen-induced production of IL-4, IL-5, IL-10 and IFN-g was detected in all three strains, with BALB/c mice generating the highest levels of IL-4, IL-5 and IL-10. Microarray analysis was used to identify genes differentially regulated in lung tissue after OVA challenge. Differentially regulated genes in the lungs of the asthma-susceptible C57BL/6 and BALB/c strains numbered 242 and 145, respectively, whereas only 42 genes were differentially expressed in the resistant CBA/Ca strain. In C57BL/6 mice, transcripts were enriched for adhesion molecules and this was associated with high levels of eosinophil recruitment. Differentially regulated genes in the lungs of only the asthma-susceptible strains numbered 64 and several of these have not previously been associated with asthma. Many of the genes differentially regulated in the susceptible strains were enzymes involved in inflammation. Using network analysis, mRNA for the anti-apoptotic protein survivin was found to be up-regulated in the lungs following allergen challenge. Survivin mRNA and protein were also expressed at high levels in eosinophils recovered by bronchoalveolar lavage from BALB/c and C57BL/6 mice. We propose that rapid apoptosis of lung eosinophils due to low expression of survivin contributes to the limitation of pathology in CBA/Ca mice

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Celtic Fire

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