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Animal manures and municipal biosolids recycled onto crop production land carry antibiotic-resistant bacteria that can influence the antibiotic resistome of agricultural soils, but little is known about the contribution of bacteriophage to the dissemination of antibiotic resistance genes (ARGs) in this context. In this work, we quantified a set of ARGs in the bacterial and bacteriophage fractions of agricultural soil by quantitative PCR. All tested ARGs were present in both the bacterial and phage fractions. We demonstrate that fertilization of soil with dairy manure or human biosolids increases ARG abundance in the bacterial fraction but not the bacteriophage fraction and further show that pretreatment of dairy manure can impact ARG abundance in the bacterial fraction. Finally, we show that purified bacteriophage can confer increased antibiotic resistance to soil bacteria when combined with selective pressure. The results indicate that soilborne bacteriophage represents a substantial reservoir of antibiotic resistance and that bacteriophage could play a significant role in the horizontal transfer of resistance genes in the context of an agricultural soil microbiome. Overall, our work reinforces the advisability of composting or digesting fecal material prior to field application and suggests that application of some antibiotics at subclinical concentrations can promote bacteriophage-mediated horizontal transfer of ARGs in agricultural soil microbiomes. Overuse of antibiotics has contributed to the spread of antibiotic resistance due to the release of antibiotics, antibioticresistant bacteria, and antibiotic resistance genes (ARGs) into the environment (1). This phenomenon is mediated by horizontal gene transfer (HGT) of mobile genetic elements-such as plasmids, transposons, and integrons-between bacterial cells through conjugation and viral transduction (2-4).Transduction has been shown to occur in environmental matrices, including freshwater and wastewater; moreover, bacterial 16S ribosomal RNA sequences have been observed in the viral fraction of wastewater, confirming the ability of bacteriophage to carry bacterial genes (5, 6). In fact, while much attention has been paid to conjugation, more recent work has additionally implicated bacteriophage as a major vehicle for horizontal gene transfer and recombination (7-10).Using high-throughput sequencing of murine fecal phage populations, Modi et al. (11) demonstrated that antibiotic treatment leads to the enrichment of genes conferring resistance to the administered drug as well as to unrelated antibiotics in the phage genome. Furthermore, bacteriophage from drug-treated mice provided cultured naive microbiota with increased levels of resistance to the corresponding drug. Overall, this work concluded that antibiotic residues potentiate the transduction-mediated dissemination of ARGs.Antibiotic resistance genes have been found in the bacteriophage DNA fraction of various environmental matrices, such as activated sludge (12), urban sewage and river water (13), an...

Faces with expressions (happy, surprise, anger, fear) were presented at study. Memory for facial expressions was tested by presenting the same faces with neutral expressions and asking participants to determine the expression that had been displayed at study. In three experiments, happy expressions were remembered better than other expressions. The advantage of a happy face was observed even when faces were inverted (upside down) and even when the salient perceptual feature (broad grin) was controlled across conditions. These findings are couched in terms of source monitoring, in which memory for facial expressions reflects encoding of the dispositional context of a prior event.

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