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Translation fidelity relies on accurate aminoacylation of transfer RNAs (tRNAs) by aminoacyl-tRNA synthetases (AARSs). AARSs specific for alanine (Ala), leucine (Leu), serine, and pyrrolysine do not recognize the anticodon bases. Single nucleotide anticodon variants in their cognate tRNAs can lead to mistranslation. Human genomes include both rare and more common mistranslating tRNA variants. We investigated three rare human tRNALeu variants that mis-incorporate Leu at phenylalanine or tryptophan codons. Expression of each tRNALeu anticodon variant in neuroblastoma cells caused defects in fluorescent protein production without significantly increased cytotoxicity under normal conditions or in the context of proteasome inhibition. Using tRNA sequencing and mass spectrometry we confirmed that each tRNALeu variant was expressed and generated mistranslation with Leu. To probe the flexibility of the entire genetic code towards Leu mis-incorporation, we created 64 yeast strains to express all possible tRNALeu anticodon variants in a doxycycline-inducible system. While some variants showed mild or no growth defects, many anticodon variants, enriched with G/C at positions 35 and 36, including those replacing Leu for proline, arginine, alanine, or glycine, caused dramatic reductions in growth. Differential phenotypic defects were observed for tRNALeu mutants with synonymous anticodons and for different tRNALeu isoacceptors with the same anticodon. A comparison to tRNAAla anticodon variants demonstrates that Ala mis-incorporation is more tolerable than Leu at nearly every codon. The data show that the nature of the amino acid substitution, the tRNA gene, and the anticodon are each important factors that influence the ability of cells to tolerate mistranslating tRNAs.

Background: Prenatal exposure to phthalates, a group of synthetic chemicals widely used in consumer products, has previously been associated with adverse infant and child development. Studies also suggest that maternal depression and anxiety, may amplify the harmful effects of phthalates on infant and child neurodevelopment. Study design: Our analysis included a subset of dyads enrolled in the Atlanta African American Maternal-Child Cohort (N = 81). We measured eight phthalate metabolites in first and second trimester (8–14 weeks and 24–32 weeks gestation) maternal urine samples to estimate prenatal exposures. Phthalate metabolite concentrations were averaged across visits and natural log-transformed for analysis. Maternal symptoms of depression and anxiety were assessed using validated questionnaires (Edinberg Postnatal Depression Scale and State Trait Anxiety Inventory, respectively) and the total score on each scale was averaged across study visits. The NICU Network Neurobehavioral Scale (NNNS) was administered at two weeks of age. Our primary outcomes included two composite NNNS scores reflecting newborn attention and arousal. Linear regression was used to estimate associations between individual phthalate exposures and newborn attention and arousal. We assessed effect modification by maternal depression and anxiety. Results: Higher levels of urinary phthalate metabolites were not associated with higher levels of infant attention and arousal, but true associations may still exist given the limited power of this analysis. In models examining effect modification by maternal depression, we observed that an interquartile range increase in mono (2-ethlyhexyl) phthalate (MEHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) was associated with a significant increase in newborn arousal only among those with high depressive symptoms (MEHP: β = 0.71, 95% confidence interval [CI] = 0.10, 1.32 for high, β = −0.30, 95% CI = −0.73, 0.12 for low; MEOHP: β = 0.60, 95% CI = −0.03, 1.23 for high, β = −0.12, 95% CI = −0.58, 0.33 for low; MEHHP: β = 0.54, 95% CI = −0.04, 1.11 for high, β = −0.11, 95% CI = −0.54, 0.32 for low). Similar patterns were observed in models stratified by maternal anxiety, although CIs were wide. Conclusion: Our results suggest maternal anxiety and depression symptoms may exacerbate the effect of phthalates on infant neurodevelopment. Future studies are needed to determine the optimal levels of attention and arousal in early infancy.

Abstract The understanding of how central metabolism and fermentation pathways regulate antimicrobial susceptibility in the anaerobic pathogen Bacteroides fragilis is still incomplete. Our study reveals that B. fragilis encodes two iron‐dependent, redox‐sensitive regulatory pirin protein genes, pir1 and pir2. The mRNA expression of these genes increases when exposed to oxygen and during growth in iron‐limiting conditions. These proteins, Pir1 and Pir2, influence the production of short‐chain fatty acids and modify the susceptibility to metronidazole and amixicile, a new inhibitor of pyruvate: ferredoxin oxidoreductase in anaerobes. We have demonstrated that Pir1 and Pir2 interact directly with this oxidoreductase, as confirmed by two‐hybrid system assays. Furthermore, structural analysis using AlphaFold2 predicts that Pir1 and Pir2 interact stably with several central metabolism enzymes, including the 2‐ketoglutarate:ferredoxin oxidoreductases Kor1AB and Kor2CDAEBG. We used a series of metabolic mutants and electron transport chain inhibitors to demonstrate the extensive impact of bacterial metabolism on metronidazole and amixicile susceptibility. We also show that amixicile is an effective antimicrobial against B. fragilis in an experimental model of intra‐abdominal infection. Our investigation led to the discovery that the kor2AEBG genes are essential for growth and have dual functions, including the formation of 2‐ketoglutarate via the reverse TCA cycle. However, the metabolic activity that bypasses the function of Kor2AEBG following the addition of phospholipids or fatty acids remains undefined. Overall, our study provides new insights into the central metabolism of B. fragilis and its regulation by pirin proteins, which could be exploited for the development of new narrow‐spectrum antimicrobials in the future.

Background: Cervical stump malignancies are an uncommon finding post subtotal hysterectomy. Tumors arise from a primary cervical origin with an incidence of 1–5%. Other described malignancies can include uterine origin, ovarian origin or as metastases from another primary site. A uterine primary is an extremely rare entity and can result from remnant endometrial tissue at the stump apex. Case: 70yo female with a history of remote supracervical hysterectomy for benign indication who presented with postmenopausal spotting. Endocervical curettage of the endocervical stump revealed a grade 2 endometrioid endometrial adenocarcinoma. She was taken to the operating for a robotic radical stump trachelectomy and sentinel lymph node dissection. Conclusions: The surgical video delineates key surgical steps of robotic radical stump trachelectomy including robotic port placement and injection of ICG dye, adhesiolysis and restoration of normal anatomy, opening of the pelvic spaces and exposure of the retroperitoneum, identification and excision of pelvic sentinel lymph nodes, bladder dissection, ureterolysis and ligation of uterine remnant, ureteric tunnel dissection and mobilization of parametrial wing, delineation of a vaginal margin, colpotomy and specimen removal, and vaginal cuff closure.