Optogenetic Amplification Circuits for Light-Induced Metabolic Control.

Dynamic control of microbial metabolism is an effective strategy to improve chemical production in fermentations. While dynamic control is most often implemented using chemical inducers, optogenetics offers an attractive alternative due to the high tunability and reversibility afforded by light. However, a major concern of applying optogenetics in metabolic engineering is the risk of insufficient light penetration at high cell densities, especially in large bioreactors. Here, we present a new series of optogenetic circuits we call OptoAMP, which amplify the transcriptional response to blue light by as much as 23-fold compared to the basal circuit (OptoEXP). These circuits show as much as a 41-fold induction between dark and light conditions, efficient activation at light duty cycles as low as ∼1%, and strong homogeneous light-induction in bioreactors of at least 5 L, with limited illumination at cell densities above 40 OD600. We demonstrate the ability of OptoAMP circuits to control engineered metabolic pathways in novel three-phase fermentations using different light schedules to control enzyme expression and improve production of lactic acid, isobutanol, and naringenin. These circuits expand the applicability of optogenetics to metabolic engineering.

Long-Term Efficacy of Young-Dees Bladder Neck Reconstruction: Role of the Associated Bladder Neck Injection for the Treatment of Children With Urinary Incontinence.

OBJECTIVE: To compare the long-term efficacy of Young-Dees bladder neck reconstruction (YDBNR) alone versus YDBNR plus bladder neck injection (BNI) in patients with urinary incontinence caused by urethral sphincter insufficiency. PATIENTS AND METHODS: Between 1987 and 2006, we assessed the continence rates obtained with YDBNR and BNI as a supplementary treatment for persistent outlet insufficiency in patients with neurogenic bladder (group 1, n = 35) and bladder exstrophy (group 2, n = 20). Median postoperative follow-up was 16 years (range: 5-29). RESULTS: A total of 55 children (23 males and 32 females) underwent YDBNR at the median age of 7.6 years (range: 1.9-17.25). Only 10 patients (18%) were considered continent after the isolated YDBNR; 17% (n = 6/35) from group 1 and 20% (n = 4/20) from group 2 (p = 1). Because of unsatisfactory results after YDBNR, 81.8% (n = 45/55) received BNI. Fifteen patients (33%) became continent with an average of 2.29 injections (±1.1); 44.8% (n = 13/29) from group 1 and 12.5% (n = 2/16) from group 2. A significant difference was found on comparing the social continence rate attained with YDBNR plus BNI between patients from group 1 and group 2 (54% vs 30%, P = .04). The difference between males and females in terms of continence rates was not statistically significant. CONCLUSION: Long-term results of YDBNR are modest. BNI does increase the results of YDBNR, especially in patients with neurogenic bladder.