bRecA is central to maintaining genome integrity in bacterial cells. Despite the near-ubiquitous conservation of RecA in eubacteria, the pathways that facilitate RecA loading and repair center assembly have remained poorly understood in Bacillus subtilis. Here, we show that RecA rapidly colocalizes with the DNA polymerase complex (replisome) immediately following DNA damage or damage-independent replication fork arrest. In Escherichia coli, the RecFOR and RecBCD pathways serve to load RecA and the choice between these two pathways depends on the type of damage under repair. We found in B. subtilis that the rapid localization of RecA to repair centers is strictly dependent on RecO and RecR in response to all types of damage examined, including a site-specific double-stranded break and damage-independent replication fork arrest. Furthermore, we provide evidence that, although RecF is not required for RecA repair center formation in vivo, RecF does increase the efficiency of repair center assembly, suggesting that RecF may influence the initial stages of RecA nucleation or filament extension. We further identify singlestranded DNA binding protein (SSB) as an additional component important for RecA repair center assembly. Truncation of the SSB C terminus impairs the ability of B. subtilis to form repair centers in response to damage and damage-independent fork arrest. With these results, we conclude that the SSB-dependent recruitment of RecOR to the replisome is necessary for loading and organizing RecA into repair centers in response to DNA damage and replication fork arrest.

Background: Longitudinal clinical experiences are a common component of undergraduate medical curricula, yet these programs have not been systematically characterized in US medical schools.Objective: Our study sought to identify and characterize longitudinal clinical programs (LCPs) in US medical schools and measure associations between programs’ structures and goals.Design: Using a mixed-methods approach, we conducted a secondary analysis of data from publicly available websites. We conducted a systematic keyword search of the websites of 137 LCME-accredited US medical schools to identify LCPs. We included programs with student–patient interactions of at least six months. We categorized programs using qualitative thematic analysis and compared associations between program structures and goals.Results: We identified 98 LCPs in 69 schools. Half (52.0%) of LCPs occurred during the core clinical year. Program structures included ‘clinic attachments’ (50.0%), ‘longitudinal integrated clerkships’ (26.5%), and ‘patient attachments’ (20.4%). We identified goals in 89 programs, including ‘exposing students to specific topics, patient demographics, or practice settings’ (78.7%); ‘clinical or professional skill development’ (65.2%); and ‘understanding the patient experience’ (19.1%). Patient attachments were associated with ‘exposure to specific patient demographics’ (P = .04) and ‘understanding the patient experience’ (P = .03). Pre-clinical programs were associated with clinical skills development (P = .01).Conclusions: Our study identifies the scope and nature of LCPs in US medical schools. Understanding connections between educational structures and goals may guide program design and research investigations of educational processes and outcomes.

Female urethral stricture disease is rare and has several surgical approaches including endoscopic dilations (ENDO), urethroplasty with local vaginal tissue flap (ULT) or urethroplasty with free graft (UFG). This study aims to describe the contemporary management of female urethral stricture disease and to evaluate the outcomes of these three surgical approaches. Methods: This is a multi-institutional, retrospective cohort study evaluating operative treatment for female urethral stricture. Surgeries were grouped into three categories: ENDO, ULT, and UFG. Time from surgery to stricture recurrence by surgery type was analyzed using a Kaplan-Meier time to event analysis. To adjust for confounders, a Cox proportional hazard model was fit for time to stricture recurrence. Results: Two-hundred and ten patients met the inclusion criteria across 23 sites. Overall, 64% (n = 115/180) of women remained recurrence free at median follow-up of 14.6 months (IQR, 3-37). In unadjusted analysis, recurrence-free rates differed between surgery categories with 68% ENDO, 77% UFG and 83% ULT patients being recurrence free at 12 months. In the Cox model, recurrence rates also differed between surgery categories; women undergoing ULT and UFG having had 66% and 49% less risk of recurrence, respectively, compared to those undergoing ENDO. When comparing ULT to UFG directly, there was no significant difference of recurrence. Conclusion: This retrospective multi-institutional study of female urethral stricture demonstrates that patients undergoing endoscopic management have a higher risk of recurrence compared to those undergoing either urethroplasty with local flap or free graft.

Hsp90 C-terminal inhibitors are advantageous for the development of new cancer chemotherapeutics due to their ability to segregate client protein degradation from induction of the prosurvival heat shock response, which is a major detriment associated with Hsp90 N-terminal inhibitors under clinical investigation. Based upon prior SAR trends, a 1,2,3-triazole side chain was placed in lieu of the aryl side chain and attached to both the coumarin and biphenyl scaffold. Antiproliferative studies against SKBr3 and MCF-7 breast cancer cell lines demonstrated these triazole-containing compounds to exhibit improved activity. These compounds were shown to manifest Hsp90 inhibitory activity through Western blot analysis and represent a new scaffold upon which more potent inhibitors can be pursued.

Single-molecule fluorescence super-resolution imaging and tracking provide nanometer-scale information about subcellular protein positions and dynamics. These single-molecule imaging experiments can be very powerful, but they are best suited to high-copy number proteins where many measurements can be made sequentially in each cell. We describe artifacts associated with the challenge of imaging a protein expressed in only a few copies per cell. We image live Bacillus subtilis in a fluorescence microscope, and demonstrate that under standard single-molecule imaging conditions, unlabeled B. subtilis cells display punctate red fluorescent spots indistinguishable from the few PAmCherry fluorescent protein single molecules under investigation. All Bacillus species investigated were strongly affected by this artifact, whereas we did not find a significant number of these background sources in two other species we investigated, Enterococcus faecalis and Escherichia coli. With single-molecule resolution, we characterize the number, spatial distribution, and intensities of these impurity spots.