Bacteria frequently encounter selection by both antibiotics and lytic bacteriophages. However, the evolutionary interactions between antibiotics and phages remain unclear, in particular, whether and when phages can drive evolutionary trade-offs with antibiotic resistance. Here, we describeEscherichia coliphage U136B, showing it relies on two host factors involved in different antibiotic resistance mechanisms: 1) the efflux pump protein TolC and 2) the structural barrier molecule lipopolysaccharide (LPS). Since TolC and LPS contribute to antibiotic resistance, phage U136B should select for their loss or modification, thereby driving a trade-off between phage resistance and either of the antibiotic resistance mechanisms. To test this hypothesis, we used fluctuation experiments and experimental evolution to obtain phage-resistant mutants. Using these mutants, we compared the accessibility of specific mutations (revealed in the fluctuation experiments) to their actual success during ecological competition and coevolution (revealed in the evolution experiments). BothtolCand LPS-related mutants arise readily during fluctuation assays, withtolCmutations becoming more common during the evolution experiments. In support of the trade-off hypothesis, phage resistance viatolCmutations occurs with a corresponding reduction in antibiotic resistance in many cases. However, contrary to the hypothesis, some phage resistance mutations pleiotropically confer increased antibiotic resistance. We discuss the molecular mechanisms underlying this surprising pleiotropic result, consideration for applied phage biology, and the importance of ecology in evolution of phage resistance. We envision that phages may be useful for the reversal of antibiotic resistance, but such applications will need to account for unexpected pleiotropy and evolutionary context.

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16Bacterial pathogens are increasingly evolving drug resistance under natural selection from 17 antibiotics in medicine, agriculture, and nature. Meanwhile, bacteria ubiquitously encounter 18 bacteriophages and can rapidly evolve phage resistance. However, the role of phages in 19 interacting with drug-resistant and drug-sensitive bacteria remains unclear. To gain insight into 20 such relationships, we screened for and characterized phages that rely on the multi-drug efflux 21 pump gene tolC. First, we screened a collection of 33 environmental and commercial 22 decreases. In this study, we investigate two newly-isolated bacteriophages that rely on a bacterial 39 antibiotic resistance gene. These bacteriophages vary in their interactions with drug-resistant 40 bacteria, with one of the phages selecting for phage-resistant mutants that have mutations in the 41 antibiotic resistance gene. Further study of these new phages will be useful to understanding 42 evolutionary tradeoffs and how phages might be applied in natural settings to reverse the 43 problem of drug resistance. 44 45 46 Widespread use of antibiotics in medicine and agriculture has selected for the evolution of multi-48 drug resistant (MDR) bacterial pathogens (1). Meanwhile, bacteria frequently encounter phages, 49 which are prevalent in the human microbiota, in hospital and farm settings, and in natural 50 environments (2), and which exert selection pressure for bacteria to resist phage exploitation (3-51 7). However, the interaction between selection from antibiotics and phages, along with its role in 52 driving bacterial evolution, remain unclear, in part because these interactions depend on both the 53 environment and specific phage species. 54 55 Potential evolutionary interactions between drug resistance and phage resistance mechanisms in 56 the homologous TolC-AcrAB system in Escherichia coli and OprM-MexAB system in P. 70 aeruginosa (12). These efflux systems confer resistance to multiple antibiotics, acting as 71 generalized transporters for multiple antibiotic classes as well as detergents, dyes, and bile acids 72 (13). The outer membrane protein (OMP) components (TolC or OprM) are membrane-spanning 73 beta barrels, with peptide loops that extend outside of the cell. The extracellular loops of OMPs 74 are frequently exploited by phages as the specific binding sites for initiating phage infection (11, 75 14-16). When phages use these OMPs as receptors, bacteria face selection for reduced or 76 modified OMPs, catalyzing ecological restructuring or coevolutionary arms races that in turn 77 alter selection on the phages (6, 15, 17, 18). Additionally, loss or modification of OMP genes has 78 been shown to alter expression of other OMP genes. For example, tolC mutants have reduced 79 expression of outer membrane proteins OmpF, NmpC, and protein 2 (19). Therefore, loss of an 80 OMP gene might impact a phage either directly -by loss of the phage receptor -or indirectly, 81 through changes to the expression of the phage receptor. 82 83In this study...

B cell leukemia/lymphoma 2 (BCL-2) is a 26 kilodalton, amphipathic, anti-apoptotic protein located on the outer mitochondrial membrane. BCL-2 interacts with other anti-apoptotic and pro-apoptotic factors in order to regulate apoptosis. If a structural change occurs on the BCL-2 gene, overexpression of the BCL-2 protein can result. This causes a change in the ratio of BCL-2 to its BCL-2 Homologous 3 (BH3) ligands, preventing the release of the apoptotic signal. The primary change associated with BCL-2 overexpression in lymphomas is a t(14;18) chromosomal translocation, which causes an increase in BCL-2 transcription. The upregulation of the oncogene allows for the survival of the mutated B cells by raising the apoptotic threshold, which then dislodges regular lymphocytes in the bone marrow or lymph nodes. Lack of cell death due to overexpression of BCL-2 has been linked to hematological malignancies, specifically lymphomas and myelomas. Both B-lymphocytic cancers can result from alterations of the immunoglobulin heavy chain locus on chromosome 14. While BCL2 translocation can cause Follicular Lymphoma, BCL2 over-expression is observed in many other tumor types and likely contributes to cancer progression and drug resistance in these tumors. Treatments to inhibit BCL-2 include attempts at activation and overexpression of the pro apoptotic BH3 proteins, BCL-2 Associated X Protein (BAX) and BCL-2 Associated K protein (BAK), and creation of BH3 mimetics. Indeed, the FDA approved the BCL2 inhibitor Venetoclax (ABT-199) earlier this year for the treatment of Chronic Lymphocytic Leukemia. These treatments could help cause cancer cell death by binding to targeted anti-apoptotic proteins and causing the signal for apoptosis to be released. This could neutralize the cancerous effects of the BCL-2 oncogene upregulation. Walton High School SMART (Students Modeling A Research Topic) Team used the computer program JMOL to create a 3D printed model of BCL-2 and composed a review poster of our secondary research to investigate and demonstrate the relationship between the structure and function of this molecule. Citation Format: Abigail V. Fortier, Ally Koh, Lisa Stanovski, Alisa Kepner, Supriya Jain, Misha Ul-Islam, Ellie Walter, Lawrence Boise. Role of Bcl-2 in hematological cancer formation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4318. doi:10.1158/1538-7445.AM2017-4318