A Platform for Deep Sequence-Activity Mapping and Engineering Antimicrobial Peptides.

Developing potent antimicrobials, and platforms for their study and engineering, is critical as antibiotic resistance grows. A high-throughput method to quantify antimicrobial peptide and protein (AMP) activity across a broad continuum would be powerful to elucidate sequence-activity landscapes and identify potent mutants. Yet the complexity of antimicrobial activity has largely constrained the scope and mechanistic bandwidth of AMP variant analysis.

Extended yeast surface display linkers enhance the enrichment of ligands in direct mammalian cell selections.

Selections of yeast-displayed ligands on mammalian cell monolayers benefit from high target expression and nanomolar affinity, which are not always available. Prior work extending the yeast-protein linker from 40 to 80 amino acids improved yield and enrichment but is hypothesized to be below the optimal length, prompting evaluation of an extended amino acid linker. A 641-residue linker provided enhanced enrichment with a 2-nM affinity fibronectin ligand and 105 epidermal growth factor receptors (EGFR) per cell (14 ± 2 vs.

Computationally Aided Discovery of LysEFm5 Variants with Improved Catalytic Activity and Stability.

Bacteriophage-derived lysin proteins are potentially effective antimicrobials that would benefit from engineered improvements to their bioavailability and specific activity. Here, the catalytic domain of LysEFm5, a lysin with activity against vancomycin-resistant (VRE), was subjected to site-saturation mutagenesis at positions whose selection was guided by sequence and structural information from homologous proteins. A second-order Potts model with parameters inferred from large sets of homologous sequence information was used to predict the average change in the statistical fitness for mutant libraries with diversity at pairs of sites within the secondary catalytic shell.

Systematic Mutagenesis of Oncocin Reveals Enhanced Activity and Insights into the Mechanisms of Antimicrobial Activity.

Oncocin is a proline-rich antimicrobial peptide that inhibits protein synthesis by binding to the bacterial ribosome. In this work, the antimicrobial activity of oncocin was improved by systematic peptide mutagenesis and activity evaluation. We found that a pair of cationic substitutions (P4K and L7K/R) improves the activity by 2-4 fold (p<0.

Validation and Stabilization of a Prophage Lysin of Clostridium perfringens by Using Yeast Surface Display and Coevolutionary Models.

Bacteriophage lysins are compelling antimicrobial proteins whose biotechnological utility and evolvability would be aided by elevated stability. Lysin catalytic domains, which evolved as modular entities distinct from cell wall binding domains, can be classified into one of several families with highly conserved structure and function, many of which contain thousands of annotated homologous sequences. Motivated by the quality of these evolutionary data, the performance of generative protein models incorporating coevolutionary information was analyzed to predict the stability of variants in a collection of 9,749 multimutants across 10 libraries diversified at different regions of a putative lysin from a prophage region of a genome.

Multispecies activity screening of microcin J25 mutants yields antimicrobials with increased specificity toward pathogenic Salmonella species relative to human commensal Escherichia coli.

Modern large-scale agricultural practices that incorporate high density farming with subtherapeutic antibiotic dosing are considered a major contributor to the rise of antibiotic-resistant bacterial infections of humans with species of Salmonella being a leading agriculture-based bacterial infection. Microcin J25, a potent and highly stable antimicrobial peptide active against Enterobacteriaceae, is a candidate antimicrobial against multiple Salmonella species. Emerging evidence supports the hypothesis that the composition of the microbiota of the gastrointestinal tract prevents a variety of diseases by preventing infectious agents from proliferating.

Antimicrobial Probiotics Reduce Salmonella enterica in Turkey Gastrointestinal Tracts.

Despite the arsenal of technologies employed to control foodborne nontyphoidal Salmonella (NTS), infections have not declined in decades. Poultry is the primary source of NTS outbreaks, as well as the fastest growing meat sector worldwide. With recent FDA rules for phasing-out antibiotics in animal production, pressure is mounting to develop new pathogen reduction strategies.

Risk factors for unsuccessful prehospital laryngeal tube placement.

Introduction: Laryngeal tube (LT) airways are commonly used in the prehospital setting, but there are limited data on clinical success rates across emergency medical services (EMS) agencies. We aimed to determine factors associated with unsuccessful LT placement in the prehospital setting.

Methods: We retrospectively reviewed all King LT placement attempts by prehospital providers in 35 ground advanced life support EMS agencies and one air medical critical care service with 17 rotorwing bases, between January 1, 2006 and August 31, 2011.

Prehospital pediatric King LT-D use: a pilot study.

Objective: To determine whether prehospital providers can successfully place a pediatric King laryngeal tube (LT-D) and ventilate a Laerdal SimBaby pediatric simulator during a respiratory arrest simulation.

Methods: We studied the ability of 45 paramedics and flight nurses to place the pediatric King LT-D in a SimBaby manikin. For the purposes of this study, paramedics and flight nurses were considered equivalent, because in this air medical system they have the same scope of practice in regard to airway skills.