New metabolites from a Mariana Trench-derived actinomycete Nocardiopsis sp. HDN 17-237.

One new ß,γ-butenoate derivative phenylbutenote (1), and one new α-pyrone nocapyrone T (2) were isolated from the deep-sea derived actinomycete Nocardiopsis sp. HDN 17-237. Their structures were elucidated by extensive HRMS, IR and NMR analyses. Among them, compound 1 is the first microbial natural products bearing a rare ß,γ-butenoate moiety, and compound 2 is the first α-pyrone isolated from strain of Mariana Trench. Compounds 1 and 2 were tested for antioxidant and antibacterial activities, while none of them showed significant activity.

Preoperative automatic reminder systems and impact on quality and compliance with colonoscopy preparation: A multicenter randomized controlled trial.

OBJECTIVES: Traditional preoperative reminding services have been applied to enhance the quality of bowel preparation for colonoscopy. In this study we aimed to evaluate the effectiveness of an automated electronic reminder system (E-reminder) on improving bowel preparation and the quality of preoperative education before colonoscopy. METHODS: From August 2021 to March 2022, 833 outpatients aged 50-75 years who underwent colonoscopy were included and randomly assigned to the E-reminder group and the control group. While the control group received routine preoperative education. The E-reminder group received automatic phone call, text message reminders and web services regarding the details of bowel preparation before the colonoscopic examination. The quality of bowel preparation was evaluated by the Boston Bowel Preparation Scale (BBPS) score and the previously validated objective evaluation scale of automatic BBPS (e-BBPS). RESULTS: In manual assessment, the rate of adequate bowel preparation was improved in the E-reminder group of intention-to-treat population using BBPS (60.7% vs 54.5%, P = 0.01). The percentage of objective evaluated adequate bowel preparation using e-BBPS in the E-reminder group of per-protocol population was significantly higher than that in the control group (76.9% vs 69.2%, P = 0.02). CONCLUSIONS: E-reminder was an effective tool to improve the quality of bowel preparation and compliance with medical instructions. It may be regarded as an efficient and convenient education tool, improving the quality of medical service.

Activation and Characterization of Lanthomicins A-C by Promoter Engineering in Streptomyces chattanoogensis L10.

The emergence of drug resistance highlights the importance of new drug discovery. Microbial secondary metabolites encoded in biosynthetic gene clusters (BGCs) are a prolific source of drugs, whereas most of these BGCs are cryptic. Thus, taking strategies to activate these cryptic BGCs is of great importance for potential drug discovery. In this work, three novel pentangular polyphenols lanthomicin A-C were identified by activating a cryptic aromatic polyketide BGC through promoter engineering combined with optimization of fermentation conditions. We further confirmed the involvement of lanthomicin (ltm) BGC in biosynthesis by CRISPR-Cpf1-assisted gene editing. Based on functional analysis of homologous genes, a putative biosynthetic pathway was proposed for the three lanthomicins. Particularly, lanthomicin A showed antiproliferative activity with IC50 0.17 µM for lung cancer cell line A-549. The discovery of lanthomicins brings new members to the pentangular polyphenol subclade of aromatic polyketide and demonstrates the potential of Streptomyces as a source for drug discovery.

Improved Sliding Mode Control for Finite-Time Synchronization of Nonidentical Delayed Recurrent Neural Networks.

This brief further explores the problem of finite-time synchronization of delayed recurrent neural networks with the mismatched parameters and neuron activation functions. An improved sliding mode control approach is presented for addressing the finite-time synchronization problem. First, by employing the drive-response concept and the synchronization error of drive-response systems, a novel integral sliding mode surface is constructed such that the synchronization error can converge to zero in finite time along the constructed integral sliding mode surface. Second, a suitable sliding mode controller is designed by relying on Lyapunov stability theory such that all system state trajectories can be driven onto the predefined sliding mode surface in finite time. Moreover, it is found that the presented control approach can be conveniently verified and does not need to solve any linear matrix inequality (LMI) to guarantee the finite-time synchronization of delayed recurrent neural networks. Finally, three numerical examples are exploited to demonstrate the effectiveness of the presented control approach.