The brainstem represents a major tissue area affected by sarin organophosphate poisoning due to its function in respiratory and cardiovascular control. While the acute toxic effects of sarin on brainstem-related responses are relatively unknown, other brain areas e.g., cortex or cerebellum, have been studied more extensively. The study objective was to analyze the guinea pig brainstem toxicology response following sarin (2×LD50) exposure by proteome pathway analysis to gain insight into the complex regulatory mechanisms that lead to impairment of respiratory and cardiovascular control. Guinea pig exposure to sarin resulted in the typical acute behavior/physiology outcomes with death between 15 and 25min. In addition, brain and blood acetylcholinesterase activity was significantly reduced in the presence of sarin to 95%, and 89%, respectively, of control values. Isobaric-tagged (iTRAQ) liquid chromatography tandem mass spectrometry (LC-MS/MS) identified 198 total proteins of which 23% were upregulated, and 18% were downregulated following sarin exposure. Direct gene ontology (GO) analysis revealed a sarin-specific broad-spectrum proteomic profile including glutamate-mediated excitotoxicity, calcium overload, energy depletion responses, and compensatory carbohydrate metabolism, increases in ROS defense, DNA damage and chromatin remodeling, HSP response, targeted protein degradation (ubiquitination) and cell death response. With regards to the sarin-dependent effect on respiration, our study supports the potential interference of sarin with CO2/H(+) sensitive chemoreceptor neurons of the brainstem retrotrapezoid nucleus (RTN) that send excitatory glutamergic projections to the respiratory centers. In conclusion, this study gives insight into the brainstem broad-spectrum proteome following acute sarin exposure and the gained information will assist in the development of novel countermeasures.

Hydrocarbon fuel biofouling and biocorrosion require expensive cleanup of aviation infrastructures unless appropriate sustainment measures are applied. The identification of novel biological control agents offers promising alternatives to the current chemical biocides used in fuel sustainment. In this study, 496 microbial fuel isolates from our in-house repository were screened to identify new endogenously produced antimicrobial compounds. Using agar plug screening, liquid culture growth testing, and Jet A fuel culture assays, the two fuel-isolate strains Pseudomonas protegens #133, and Bacillus subtilis #232 demonstrated promising biocontrol activity against bacteria, yeast, and filamentous fungi. Liquid chromatography-quadrupole time of flight tandem mass spectrometry (LC-QTOF-MS/MS) of #232 culture filtrate identified several common lipopeptide antimicrobials including gageostatin C, gageopeptin B, and miscellaneous macrolactins. In contrast, LC-QTOF-MS/MS identified the siderophore pyochelin as one of the predominant compounds in #133 culture filtrate with previously demonstrated antimicrobial effect. Jet fuel microbial consortium culture testing of #133 culture filtrate including flow-cytometry live/dead cell mechanism determination demonstrated antimicrobial action against Gram-positive bacteria. The study concludes that antimicrobial compounds secreted by #133 have bactericidal effects against Gordonia sp. and cause cell death through bacterial lysis and membrane damage with potential applications in the biocidal treatment of hydrocarbon-based aviation fuels.

Acute exposure to high concentrations of H ₂ S causes severe brain injury and long-term neurological disorders. The mechanisms of H ₂ S-induced neurodegeneration are not known. To better understand the cellular and molecular mechanisms of H2S-induced neurodegeneration we used a broad-spectrum proteomic analysis approach to search for key molecules in H2S-induced neurotoxicity. Mice were subjected to acute whole body exposure of up to750 ppm of H ₂ S. The H2S-treated group showed behavioral motor deficits and developed severe lesions in the inferior colliculus (IC), part of the brainstem. The IC was microdissected for proteomic analysis. Tandem mass tags (TMT) liquid chromatography mass spectrometry (LC-MS/MS)-based quantitative proteomics was applied for protein identification and quantitation. LC-MS/MS was able to identify 598, 562, and 546 altered proteomic changes for day 1 (2 h post H ₂ S exposure), day 2, and day 4 of H ₂ S exposure, respectively. Mass spectrometry data were analyzed by Perseus 1.5.5.3 statistical analysis, and gene ontology heat map clustering. Quantitative real-time PCR was used to confirm some of the H ₂ S-dependent proteomics changes. Taken together, acute exposure to H ₂ S induced behavioral motor deficits along with progressive neurodegeneration including disruption of several biological processes in the IC such as cellular morphology, energy metabolism, and calcium signaling. The obtained broad-spectrum proteomics data may provide important clues to elucidate mechanisms of H ₂ S-induced neurotoxicity. Highlights: Mice exposed to H ₂ S recapitulated H ₂ S-induced neurotoxicity manifested in humans. The IC in the mouse brain is the most sensitive to H ₂ S-induced neurodegeneration. Proteomic expressions of key proteins were validated at transcription level. Several biological pathways were dysregulated by H ₂ S exposure.

Hydrocarbon fuel biofouling and biocorrosion requires expensive cleanup of aviation infrastructures unless appropriate sustainment measures are applied. Alternative to current chemical biocides used in fuel sustainment, the identification of novel biological control agents offers promising alternatives. In this study, 493 microbial fuel isolates from our in-house repository were screened to identify new endogenously produced antimicrobial compounds. Using agar plug screening, liquid culture growth testing, and Jet A fuel culture assays, the two fuel isolate strains Pseudomonas protegens #133, and Bacillus subtilis # 232 demonstrated promising biocontrol activity against bacteria, yeast and filamentous fungi. Mass spectrometry analysis (LC-MS/MS) of #232 culture filtrate identified several common lipopeptide antimicrobials including gageostatin C, gageopeptin B, and miscellaneous macrolactins. In contrast, LC-MS/MS identified the siderophore pyochelin as one of the predominant compounds in #133 culture filtrate with previously demonstrated antimicrobial effect. Jet fuel microbial consortium culture testing of #133 culture filtrate including flow-cytometry live/dead cell mechanism determination demonstrated antimicrobial action against Gram-positive Gordonia sp. bacteria. The study concludes that antimicrobial compounds secreted by #133 have bactericidal effect against Gordonia sp. and cause cell death through bacterial lysis and membrane damage with potential applications in biocidal treatment of hydrocarbon-based aviation fuels.