A genome-wide cytotoxicity screen of cluster F1 mycobacteriophage Girr reveals novel inhibitors of Mycobacterium smegmatis growth.

Over the past decade, thousands of bacteriophage genomes have been sequenced and annotated. A striking observation from this work is that known structural features and functions cannot be assigned for >65% of the encoded proteins. One approach to begin experimentally elucidating the function of these uncharacterized gene products is genome-wide screening to identify phage genes that confer phenotypes of interest like inhibition of host growth. This study describes the results of a screen evaluating the effects of overexpressing each gene encoded by the temperate Cluster F1 mycobacteriophage Girr on the growth of the host bacterium Mycobacterium smegmatis. Overexpression of 29 of the 102 Girr genes (~28% of the genome) resulted in mild to severe cytotoxicity. Of the 29 toxic genes described, 12 have no known function and are predominately small proteins of <125 amino acids. Overexpression of the majority of these 12 cytotoxic no known functions proteins resulted in moderate to severe growth reduction and represent novel antimicrobial products. The remaining 17 toxic genes have predicted functions, encoding products involved in phage structure, DNA replication/modification, DNA binding/gene regulation, or other enzymatic activity. Comparison of this dataset with prior genome-wide cytotoxicity screens of mycobacteriophages Waterfoul and Hammy reveals some common functional themes, though several of the predicted Girr functions associated with cytotoxicity in our report, including genes involved in lysogeny, have not been described previously. This study, completed as part of the HHMI-supported SEA-GENES project, highlights the power of parallel, genome-wide overexpression screens to identify novel interactions between phages and their hosts.

Genome Sequence of VanLee, a Singleton Actinobacteriophage That Infects Multiple Gordonia Strains.

VanLee is a singleton phage that was isolated from soil in Florida using Gordonia rubripertincta NRRL B-16540 as the host. The genome is 84,560 bp and has a GC content of 67.8%. VanLee has 164 predicted protein-coding genes and one tRNA. VanLee can infect Gordonia terrae with the same efficiency as G. rubripertincta.

Making Sense of Modeling in Elementary Literacy Instruction.

Although modeling is an instructional approach commonly named in literacy education circles, the authors struggled to articulate the essential features of modeling to preservice teachers. This was a problem for them and for the preservice teachers with whom they worked. The problem also represents a larger one in the field, which is that educators are still building that which is the foundation of most other professions: a shared professional language. Efforts to build a shared professional language are important for literacy educators seeking to reflect on and improve their craft, literacy leaders working to make change at the school level, and mentor teachers and teacher educators tasked with preparing the next generation of teachers. The authors describe their efforts to articulate and represent modeling in elementary literacy instruction.

Utah obstetricians' opinions of planned home birth and conflicting NICE/ACOG guidelines: A qualitative study.

BACKGROUND: The United Kingdom's National Institute for Health and Care Excellence (NICE) recently published recommendations that support planned home birth for low-risk women. The American College of Obstetricians and Gynecologists (ACOG) remains wary of planned home birth, asserting that hospitals and birthing centers are the safest birth settings. Our objective was to examine opinions of obstetricians in Salt Lake City, Utah about home birth in the context of rising home birth rates and conflicting guidelines. METHODS: Participants were recruited through online searches of Salt Lake City obstetricians and through snowball sampling. We conducted individual interviews exploring experiences with and attitudes toward planned home birth and the ACOG/NICE guidelines. RESULTS: Fifteen obstetricians who varied according to years of experience, location of medical training, sex, and subspecialty (resident, OB/GYN, maternal-fetal medicine specialist) were interviewed. Participants did not recommend home birth but supported a woman's right to choose her birth setting. Obstetrician opinions about planned home birth were shaped by misconceptions of home birth benefits, confusion surrounding the scope of care at home and among home birth providers, and negative transfer experiences. Participants were unfamiliar with the literature on planned home birth and/or viewed the evidence as unreliable. Support for ACOG guidelines was high, particularly in the context of the United States health care setting. CONCLUSION: Physician objectivity may be limited by biases against home birth, which stem from limited familiarity with published evidence, negative experiences with home-to-hospital transfers, and distrust of home birth providers in a health care system not designed to support home birth.

ERp29 triggers a conformational change in polyomavirus to stimulate membrane binding.

Membrane penetration of nonenveloped viruses is a poorly understood process. We have investigated early stages of this process by studying the conformational change experienced by polyomavirus (Py) in the lumen of the endoplasmic reticulum (ER), a step that precedes its transport into the cytosol. We show that a PDI-like protein, ERp29, exposes the C-terminal arm of Py's VP1 protein, leading to formation of a hydrophobic particle that binds to a lipid bilayer; this reaction likely mimics initiation of Py penetration across the ER membrane. Expression of a dominant-negative ERp29 decreases Py infection, indicating ERp29 facilitates viral infection. Interestingly, cholera toxin, another toxic agent that crosses the ER membrane into the cytosol, is unfolded by PDI in the ER. Our data thus identify an ER factor that mediates membrane penetration of a nonenveloped virus and suggest that PDI family members are generally involved in ER remodeling reactions.