Turkeys ( Meleagris gallopavo ) provide a globally important source of protein and constitute the second most important source of poultry meat in the world. Bacterial diseases are common in commercial poultry production causing significant production losses for farmers. Due to the increasingly recognized problems associated with large-scale/indiscriminant antibiotic use in agricultural settings, poultry producers need alternative methods to control common bacterial pathogens. In this study we compared the cecal microbiota of wild and domestic turkeys, hypothesizing that environmental pressures faced by wild birds may select for a disease-resistant microbial community. Sequence analysis of 16S rRNA genes amplified from cecal samples indicate that free-roaming wild turkeys carry a rich and variable microbiota compared to domestic turkeys raised on large-scale poultry farms. Wild turkeys also had very low levels of Staphylococcus, Salmonella and E. coli when compared to domestic turkeys. E. coli strains isolated from wild or domestic turkey cecal samples also belong to distinct phylogenetic backgrounds and differ in their propensity to carry virulence genes. E. coli strains isolated from factory-raised turkeys were far more likely to carry genes for capsule ( kpsII , kpsIII ) or siderophore ( iroN , fyuA ) synthesis than those isolated from wild turkeys. These results suggest that the microbiota of wild turkeys may provide colonization resistance against common poultry pathogens. Importance Due to the increasingly recognized problems associated with antibiotic use in agricultural settings, poultry producers need alternative methods to control common bacterial pathogens. In this study we compare the microbiota of wild and domestic turkeys. Results suggest that free ranging wild turkeys carry a distinct microbiome when compared to farm raised turkeys. The microbiome of wild birds contains very low levels of poultry pathogens compared to farm raised birds. The microbiomes of wild turkeys may be used to guide development of new ways to control disease in large scale poultry production.

Cohesion of biofilms made by Yersinia pestis and Yersinia pseudotuberculosis (Yptb) has been attributed solely to an extracellular polysaccharide matrix encoded by the hms genes (Hms-ECM). However, mutations in the Yptb BarA/UvrY/CsrB regulatory cascade enhance biofilm stability without dramatically increasing Hms-ECM production. We found that treatment with proteinase K enzyme effectively destabilized Yptb csrB mutant biofilms, suggesting that cell-cell interactions might be mediated by protein adhesins or extracellular matrix proteins. We identified an uncharacterized trimeric autotransporter lipoprotein (YPTB2394), repressed by csrB, which has been referred to as YadE. Biofilms made by a ΔyadE mutant strain were extremely sensitive to mechanical disruption. Overexpression of yadE in wild-type Yptb increased biofilm cohesion, similar to biofilms made by csrB or uvrY mutants. We found that the Rcs signaling cascade, which represses Hms-ECM production, activated expression of yadE. The yadE gene appears to be functional in Yptb but is a pseudogene in modern Y. pestis strains. Expression of functional yadE in Y. pestis KIM6+ weakened biofilms made by these bacteria. This suggests that although the YadE autotransporter protein increases Yptb biofilm stability, it may be incompatible with Hms-ECM production that is essential for Y. pestis biofilm production in fleas. Inactivation of yadE in Y. pestis may be another instance of selective gene loss in the evolution of flea-borne transmission by this species. IMPORTANCE The evolution of Yersinia pestis from its Y. pseudotuberculosis (Yptb) ancestor involved gene acquisition and gene losses, leading to differences in biofilm production. Characterizing the unique biofilm features of both species may provide better understanding of how each adapts to its specific niches. This study identifies a trimeric autotransporter YadE that promotes biofilm stability of Yptb but which has been inactivated in Y. pestis, perhaps because it is not compatible with Hms polysaccharide that is crucial for biofilms inside fleas. We also reveal that the Rcs signaling cascade, which represses Hms expression, activates YadE in Yptb. The ability of Yptb to use polysaccharide or YadE protein for cell-cell adhesion may help it produce biofilms in different environments.

Diverse bacterial species use type IVa pili (T4aP) to interact with their environments. The dynamic extension and retraction of T4aP is critical for their function, but the mechanisms that regulate this dynamic activity remain poorly understood. T4aP are typically extended via the activity of a dedicated extension motor ATPase and retracted via the action of an antagonistic retraction motor ATPase called PilT. These motors are generally functionally independent, and loss of PilT commonly results in T4aP hyperpiliation due to undeterred pilus extension. However, for the mannose-sensitive hemagglutinin (MSHA) T4aP of Vibrio cholerae, the loss of PilT unexpectedly results in a loss of surface piliation. Here, we employ a combination of genetic and cell biological approaches to dissect the underlying mechanism. Our results demonstrate that PilT is necessary for MSHA pilus extension in addition to its well-established role in promoting MSHA pilus retraction. Through a suppressor screen, we also provide genetic evidence that the MshA major pilin impacts pilus extension. Together, these findings contribute to our understanding of the factors that regulate pilus extension and describe a previously uncharacterized function for the PilT motor ATPase.

15Cohesion of biofilms made by Yersinia pestis and Yersinia pseudotuberculosis (Yptb) has been 16 attributed solely to an extracellular polysaccharide matrix encoded by the hms genes (Hms-17 ECM). However, mutations in the Yptb BarA/UvrY/CsrB regulatory cascade enhance biofilm 18 stability without dramatically increasing Hms-ECM production. We found that treatment with 19 proteinase K enzyme effectively destabilized Yptb csrB mutant biofilms, suggesting that cell-cell 20 interactions might be mediated by protein adhesins or extracellular matrix proteins. We 21 identified an uncharacterized trimeric autotransporter lipoprotein (YPTB2394), repressed by 22 csrB, which has been referred to as YadE. Biofilms made by a yadE mutant strain were 23 extremely sensitive to mechanical disruption. Overexpression of yadE in wild-type Yptb 24 increased biofilm cohesion, similar to biofilms made by csrB or uvrY mutants. We found that the 25 Rcs signaling cascade, which represses Hms-ECM production, activated expression of yadE. The 26 yadE gene appears to be functional in Yptb but is a pseudogene in modern Y. pestis strains. 27 Expression of functional yadE in Y. pestis KIM6+ altered the production of Hms-ECM and 28 weakened biofilms made by these bacteria. This suggests that although the YadE autotransporter 29 protein increases Yptb biofilm stability, it may be incompatible with Hms-ECM production that 30 is essential for Y. pestis biofilm production in fleas. Inactivation of yadE in Y. pestis may be 31 another instance of selective gene loss in the evolution of flea-borne transmission by this species. 32 33 3 IMPORTANCE 34The evolution of Yersinia pestis from its Y. pseudotuberculosis (Yptb) ancestor involved gene 35 acquisition and gene losses, leading to differences in biofilm production. Characterizing the 36 unique biofilm features of both species may provide better understanding of how each adapts to 37 its specific niches. This study identifies a trimeric autotransporter YadE that promotes biofilm 38 stability of Yptb but which has been inactivated in Y. pestis, likely because it is not compatible 39 with Hms polysaccharide that is crucial for biofilms inside fleas. We also reveal that the Rcs 40 signaling cascade, which represses Hms expression in Y. pestis, activates YadE in Yptb. The 41 ability of Yptb to use polysaccharide or YadE protein for cell-cell adhesion may help it produce 42 biofilms in different environments. 44Environmental persistence, host interaction, and transmission of Yersinia depend on 45 biofilms, which are tightly regulated by both transcriptional and post-transcriptional control 46 mechanisms [1, 2]. Arguably, the best studied Yersinia biofilms are those made by Y. pestis 47 while in the flea digestive tract that block the proventriculus and increase transmission to new 48 hosts during flea feeding. These biofilms require the HmsHFRS proteins to produce and export a 49 polysaccharide extracellular matrix of poly-ß-1,6-N-acetylglucosamine that is crucial in forming 50 and maintaining ba...

Turkeys (Meleagris gallopavo) provide a globally important source of protein and constitute the second most important source of poultry meat in the world.  Bacterial diseases are common in commercial poultry production causing significant production losses for farmers. Due to the increasingly recognized problems associated with large-scale/indiscriminant antibiotic use in agricultural settings, poultry producers need alternative methods to control common bacterial pathogens. In this study we compared the cecal microbiota of wild and domestic turkeys, hypothesizing that environmental pressures faced by wild birds may select for a disease-resistant microbial community.  Sequence analysis of 16S rRNA genes amplified from cecal samples indicate that free-roaming wild turkeys carry a rich and variable microbiota compared to domestic turkeys raised on large-scale poultry farms. Wild turkeys also had very low levels of Staphylococcus, Salmonella and E. coli when compared to domestic turkeys.  E. coli strains isolated from wild or domestic turkey cecal samples also belong to distinct phylogenetic backgrounds and differ in their propensity to carry virulence genes. E. coli strains isolated from factory-raised turkeys were far more likely to carry genes for capsule (kpsII, kpsIII) or siderophore (iroN, fyuA) synthesis than those isolated from wild turkeys.  These results suggest that the microbiota of wild turkeys may provide colonization resistance against common poultry pathogens.