Clostridium perfringens is the third leading cause of human foodborne bacterial disease and is the presumptive etiologic agent of necrotic enteritis among chickens. Treatment of poultry with antibiotics is becoming less acceptable. Endolysin enzymes are potential replacements for antibiotics. Many enzymes are added to animal feed during production and are subjected to high-heat stress during feed processing. To produce a thermostabile endolysin for treating poultry, an E. coli codon-optimized gene was synthesized that fused the N-acetylmuramoyl-L-alanine amidase domain from the endolysin of the thermophilic bacteriophage ɸGVE2 to the cell-wall binding domain (CWB) from the endolysin of the C. perfringens-specific bacteriophage ɸCP26F. The resulting protein, PlyGVE2CpCWB, lysed C. perfringens in liquid and solid cultures. PlyGVE2CpCWB was most active at pH 8, had peak activity at 10 mM NaCl, 40% activity at 150 mM NaCl and was still 16% active at 600 mM NaCl. The protein was able to withstand temperatures up to 50° C and still lyse C. perfringens. Herein, we report the construction and characterization of a thermostable chimeric endolysin that could potentially be utilized as a feed additive to control the bacterium during poultry production.

Starvation is a complex physiological state that induces changes in protein expression to ensure survival. The insect midgut is sensitive to changes in dietary content as it is at the forefront of communicating information about incoming nutrients to the body via hormones. Therefore, a DIA proteomics approach was used to examine starvation physiology and, specifically, the role of midgut neuropeptide hormones in a representative lepidopteran, Manduca sexta. Proteomes were generated from midguts of M. sexta fourth-instar caterpillars, starved for 24 h and 48 h, and compared to fed controls. A total of 3047 proteins were identified, and 854 of these were significantly different in abundance. KEGG analysis revealed that metabolism pathways were less abundant in starved caterpillars, but oxidative phosphorylation proteins were more abundant. In addition, six neuropeptides or related signaling cascade proteins were detected. Particularly, neuropeptide F1 (NPF1) was significantly higher in abundance in starved larvae. A change in juvenile hormone-degrading enzymes was also detected during starvation. Overall, our results provide an exploration of the midgut response to starvation in M. sexta and validate DIA proteomics as a useful tool for quantifying insect midgut neuropeptide hormones.

Spaceflight profoundly impacts cardiovascular physiology. To gain insight into the underlying molecular adaptations, we examined the female cardiac proteome during spaceflight and recovery. We hypothesized that spaceflight remodels the cardiac proteome, including mitochondrial bioenergetics and redox homeostasis pathways, during both flight and recovery, altering cardiovascular health risk. Proteomic analysis was performed on hearts from female C57BL/6J mice flown aboard the International Space Station (ISS) for 55 to 60 days as part of the NASA Rodent Research-20 (RR-20) study and a recovery cohort returned to Earth after 42 days, with sampling occurring five days after landing, and corresponding ground controls. Consistent with our hypothesis, spaceflight enriched mitochondrial bioenergetic pathways relative to ground controls, including cellular respiration, the tricarboxylic acid cycle, and oxidative phosphorylation. These changes occurred alongside the remodeling of antioxidant pathways, suggesting altered redox regulation during flight and increased susceptibility to reactive oxygen species (ROS) accumulation in the heart versus controls. Postflight recovery was characterized by distinct metabolic, redox, and structural remodeling signatures, including pathways associated with sarcomere organization, contractile function, and extracellular matrix regulation. These findings reveal cardiac proteomic remodeling during and after spaceflight and provide molecular insights relevant to cardiovascular risk assessment and countermeasure development for exploration missions.