Origin of the 3-methylglutaryl moiety in caprazamycin biosynthesis.

BACKGROUND: Caprazamycins are liponucleoside antibiotics showing bioactivity against Gram-positive bacteria including clinically relevant Mycobacterium tuberculosis by targeting the bacterial MraY-translocase. Their chemical structure contains a unique 3-methylglutaryl moiety which they only share with the closely related liposidomycins. Although the biosynthesis of caprazamycin is understood to some extent, the origin of 3-methylglutaryl-CoA for caprazamycin biosynthesis remains elusive. RESULTS: In this work, we demonstrate two pathways of the heterologous producer Streptomyces coelicolor M1154 capable of supplying 3-methylglutaryl-CoA: One is encoded by the caprazamycin gene cluster itself including the 3-hydroxy-3-methylglutaryl-CoA synthase Cpz5. The second pathway is part of primary metabolism of the host cell and encodes for the leucine/isovalerate utilization pathway (Liu-pathway). We could identify the liu cluster in S. coelicolor M1154 and gene deletions showed that the intermediate 3-methylglutaconyl-CoA is used for 3-methylglutaryl-CoA biosynthesis. This is the first report of this intermediate being hijacked for secondary metabolite biosynthesis. Furthermore, Cpz20 and Cpz25 from the caprazamycin gene cluster were found to be part of a common route after both individual pathways are merged together. CONCLUSIONS: The unique 3-methylglutaryl moiety in caprazamycin originates both from the caprazamycin gene cluster and the leucine/isovalerate utilization pathway of the heterologous host. Our study enhanced the knowledge on the caprazamycin biosynthesis and points out the importance of primary metabolism of the host cell for biosynthesis of natural products.

Family role in paediatric safety incidents: a retrospective study protocol.

INTRODUCTION: Healthcare-associated harm is an international public health issue. Children are particularly vulnerable to this with 15%-35% of hospitalised children experiencing harm during medical care. While many factors increase the risk of adverse events, such as children's dependency on others to recognise illness, children have a unique protective factor in the form of their family, who are often well placed to detect and prevent unsafe care. However, families can also play a key role in the aetiology of unsafe care.We aim to explore the role of families, guardians and parents in paediatric safety incidents, and how this may have changed during the pandemic, to learn how to deliver safer care and codevelop harm prevention strategies across healthcare settings. METHODS AND ANALYSIS: This will be a retrospective study inclusive of an exploratory data analysis and thematic analysis of incident report data from the Learning from Patient Safety Events service (formerly National Reporting and Learning System), using the established PatIent SAfety classification system. Reports will be identified by using specific search terms, such as *parent* and *mother*, to capture narratives with explicit mention of parental involvement, inclusive of family members with parental and informal caregiver responsibilities.Paediatricians and general practitioners will characterise the reports and inter-rater reliability will be assessed. Exploratory descriptive analysis will allow the identification of types of incidents involving parents, contributing factors, harm outcomes and the specific role of the parents including inadvertent contribution to or mitigation of harm. ETHICS AND DISSEMINATION: This study was approved by Cardiff University Research Ethics Committee (SMREC 22/32). Findings will be submitted to a peer-reviewed journal, presented at international conferences and presented at stakeholder workshops.