An updated catalogue of diverse type II polyketide synthase biosynthetic gene clusters captured from large-scale nucleotide databases.

Nature serves as a rich source of molecules with immense chemical diversity. Aptly named, these 'natural products' boast a wide variety of environmental, medicinal and industrial applications. Type II polyketides, in particular, confer substantial medicinal benefits, including antibacterial, antifungal, anticancer and anti-inflammatory properties. These molecules are produced by enzyme assemblies known as type II polyketide synthases (PKSs), which use domains such as the ketosynthase chain-length factor and acyl carrier protein to produce polyketides with varying lengths, cyclization patterns and oxidation states. In this work, we use a novel bioinformatic workflow to identify biosynthetic gene clusters (BGCs) that code for the core type II PKS enzymes. This method does not rely on annotation and thus was able to unearth previously 'hidden' type II PKS BGCs. This work led us to identify over 6000 putative type II PKS BGCs spanning a diverse set of microbial phyla, nearly double those found in most recent studies. Notably, many of these newly identified BGCs were found in non-actinobacteria, which are relatively underexplored as sources of type II polyketides. Results from this work lay an important foundation for future bioprospecting and engineering efforts that will enable sustainable access to diverse and structurally complex molecules with medicinally relevant properties.

Validated, Consensus-Based Second- and Third-Trimester Sonographic Learning Objectives for the Obstetrics Clerkship.

OBJECTIVE: Currently, there are no established guidelines for obstetric ultrasound training at the core medical student clerkship level. Our objective was to develop practical, consensus-based learning objectives in second- and third-trimester ultrasound and assess the feasibility of implementing these objectives into a clinical curriculum. STUDY DESIGN: Using the modified Delphi approach, a panel of expert stakeholders (n = 23) was assembled to reach consensus on the proposed learning objectives. A model curriculum was created consisting of a video tutorial, in-person training, and an optional tracker and piloted at two academic medical centers. Participant perception of acquired ultrasound skills and the program were assessed using a modified, previously validated survey. Pre- and postprogram survey responses were compared using the Chi-squared test of association. A p-value of <0.05 was considered statistically significant. RESULTS: The expert panel reached consensus on five learning objectives to include determination of fetal number and presentation, assessment of fetal heart rate, determination of placental location, assessment of amniotic fluid volume, and a general understanding of the biophysical profile and its indications. A total of 26 students participated in the piloted curriculum. On completion, a majority of participants reported improved confidence in understanding and performing prenatal ultrasound in the second and third trimesters (p < 0.05). The majority of participants valued a hands-on ultrasound curriculum. CONCLUSION: We propose practical, consensus-based learning objectives for second- and third-trimester sonography during the core clerkship with demonstrated feasibility in a two-center pilot program. KEY POINTS: · Ultrasound is a valuable skill for medical students.. · Specific learning objectives in obstetric ultrasound are currently lacking.. · We propose consensus-based objectives and a model curriculum.. · A two-center pilot study demonstrated efficacy..