Background: Gram-positive bacteria secrete pilins through the Sec translocon in unfolded states. Results: Disruption of pilus disulfide bonds or genetic disruption of oxidoreductase-encoding genes mdbA and vkor abrogates pilus assembly in Actinomyces oris. Conclusion: MdbA and VKOR constitute a disulfide bond-forming machine in A. oris. Significance: Oxidative protein folding may be common in Actinobacteria and an attractive target for antimicrobials.

Summary The Gram-positive pathogen Corynebacterium diphtheriae exports through the Sec apparatus many extracellular proteins that include the key virulence factors diphtheria toxin and the adhesive pili. How these proteins attain their native conformations after translocation as unfolded precursors remains elusive. The fact that the majority of these exported proteins contain multiple cysteine residues and that several membrane-bound oxidoreductases are encoded in the corynebacterial genome suggests the existence of an oxidative protein-folding pathway in this organism. Here we show that the shaft pilin SpaA harbors a disulfide bond in vivo and alanine substitution of these cysteines abrogates SpaA polymerization and leads to the secretion of degraded SpaA peptides. We then identified a thiol-disulfide oxidoreductase (MdbA), whose structure exhibits a conserved thioredoxin-like domain with a CPHC active site. Remarkably, deletion of mdbA results in a severe temperature-sensitive cell division phenotype. This mutant also fails to assemble pilus structures and is greatly defective in toxin production. Consistent with these defects, the ΔmdbA mutant is attenuated in a guinea pig model of diphtheritic toxemia. Given its diverse cellular functions in cell division, pilus assembly and toxin production, we propose that MdbA is a component of the general oxidative folding machine in C. diphtheriae.

ObjectiveTo evaluate patient perceptions of preoperative reproductive counseling and to evaluate complications and pregnancy outcomes in women who had radical trachelectomy (RT) for early stage cervical cancer.MethodsPatients who underwent RT from January 1, 2004, through July 31, 2017, and had been cancer free for more than 1 year after RT were eligible; consented patients were sent a 16-item online survey.ResultsOf the 58 eligible patients, 39 patients (67%) completed the questionnaire. Eighteen patients (46%) reported receiving reproductive counseling and 26 (68%) reported receiving counseling about pregnancy risks and complications prior to RT, mainly delivered by gynecologic oncologists. Twenty-nine patients (74%) reported having a complication after RT, and cervical stenosis was the most common complication, occurring in 13 patients (33%). Twenty-four patients actively attempted to conceive after RT, and 20 pregnancies were achieved in 13 patients for a pregnancy rate of 54%. Eight pregnancies were spontaneous and 12 required a fertility treatment. There were 5 spontaneous first-trimester miscarriages; 14 of the 20 pregnancies (70%) resulted in live births. The median time to conception was 13.5 months (range, 1–120).ConclusionA significant proportion of women with early stage cervical cancer do not receive adequate reproductive counseling before RT, and many women undergoing RT experience complications that can negatively impact their fertility. We recommend a preoperative consultation with a reproductive endocrinologist for all patients considering RT.

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