How To Prepare for the Unexpected: a Public Health Laboratory Response.

Public health laboratories (PHLs) continue to face internal and external challenges to their abilities to provide successful, timely responses to public health crises and emerging threats. These laboratories are mandated to maintain the health of their communities by identifying, diagnosing, and warning constituents of potential and real health emergencies. Due to the changing characteristics of public health threats and their cross-jurisdictional nature, laboratories are facing increased pressure to ensure that they respond in a consistent and coordinated manner. Here, the Association of Public Health Laboratories (APHL) Emerging Leader Program Cohort 11 members have compiled stories from subject matter experts (SMEs) at PHLs with direct involvement in crises to determine the characteristics of a successful response. Experts examined a diverse selection of emerging threats from across PHLs, including infectious diseases, opioids, natural disasters, and government shutdowns. While no public health crisis will be identical to another, overarching themes were consistent across subjects. Experiences from SMEs that could improve future responses to emerging threats are highlighted.

Engineering of cysteine residues leads to improved production of a human dipeptidase enzyme in E. coli.

Low yields, poor folding efficiencies and improper disulfide bridge formation limit large-scale production of cysteine-rich proteins in Escherichia coli. Human renal dipeptidase (MDP), the only human beta-lactamase known to date, is a homodimeric enzyme, which contains six cysteine residues per monomer. It hydrolyses penem and carbapenem beta-lactam antibiotics and can cleave dipeptides containing amino acids in both D: - and L: -configurations. In this study, MDP accumulated in inactive form in high molecular weight, disulfide-linked aggregates when produced in the E. coli periplasm. Mutagenesis of Cys361 that mediates dimer formation and Cys93 that is unpaired in the native MDP led to production of soluble recombinant enzyme, with no change in activity compared with the wild-type enzyme. The removal of unpaired or structurally inessential cysteine residues in this manner may allow functional production of many multiply disulfide-linked recombinant proteins in E. coli.