Characterization of Hydrogen Peroxide–ResistantAcinetobacterSpecies Isolated during the Mars Phoenix Spacecraft Assembly

• DOI: 10.1089/ast.2014.1193
• Publication Date: 2014-09-22T16:20:05Z
• Authors: I. Derecho; K.B. McCoy; P. Vaishampayan; K. Venkateswaran; R. Mogul
• Keywords: Phoenix

The microbiological inventory of spacecraft and the associated assembly facility surfaces represent primary pool forward contaminants that may impact integrity life-detection missions. Herein, we report on characterization several strains hydrogen peroxide-resistant Acinetobacter, which were isolated during Mars Phoenix lander assembly. All Phoenix-associated Acinetobacter possessed very high catalase specific activities, strain, A. gyllenbergii 2P01AA, displayed a survival against peroxide (no loss in 100 mM H2O2 for 1 h) is perhaps highest known among Gram-negative non-spore-forming bacteria. Proteomic characterizations reveal mechanism inclusive proteins coupled to degradation (catalase alkyl hydroperoxide reductase), energy/redox management (dihydrolipoamide dehydrogenase), protein synthesis/folding (EF-G, EF-Ts, peptidyl-tRNA hydrolase, DnaK), membrane functions (OmpA-like ABC transporter-related protein), nucleotide metabolism (HIT family hydrolase). Together, these survivability biochemical parameters support hypothesis oxidative tolerance related features are measurable phenotypes or outcomes microbial facilities, where low-humidity (desiccation) clean (low-nutrient) conditions serve as selective pressures. Hence, spacecraft-associated due conferred tolerances, ultimately hinder efforts reduce bioburden when using chemical sterilants, thus suggesting bacteria need be included accounting future