| Several aspects of microbiology that are relevant to spaceflight were examined. In order to evaluate the long-term effects of microgravity on bacteria, E. coli cells were grown under simulated microgravity for 1000 generations and gene expression patterns were analyzed in comparison with short-term exposure. The analysis revealed that 357 genes were significantly expressed. Fimbriae encoding genes were significantly up-regulated whereas genes encoding for the flagellar motor complex were down-regulated. Additionally, 81 genes which were significantly expressed have been found to be implicated in and/or associated with biofilm formation. The remaining up-regulated genes seemed to be involved in a response that trigger gene members of the type II secretion complex which has been involved in virulence factors and members of the multidrug efflux system which confer resistance to a multitude of antimicrobial agents and antibiotics. Thus, such general transcriptional expression may predispose the cells to be more efficient to attach to surfaces and/or other cells and confer thereby resistance to antibiotics. The long term effects of microbial populations to microgravity therefore may be of concern for the safety of the astronauts and should be studied further.;In order to insure that potentially hazardous bacteria do not escape from life support systems which are essential to long duration spaceflight, an effective tracking system is needed. To address this, an easily detectable strain of E. coli, PCPHR, which expresses a stable artificial RNA (aRNA) was also subjected to gene expression studies. Only one gene, ( deoC) whose primary function is to degrade and/or salvage nucleotides, was unequivocally affected in PCPHR. This result suggests PCPHR is ideal as an efficient and simple system for source tracking and monitoring for space applications as the organisms is extremely unlikely to behave differently than a normal E. coli strain.;Finally, microorganisms are as ubiquitous in space as on Earth. Thus, a sensitive, highly specific system to detect and monitor contaminants is required. A new set of 29 probes targeting higher order taxa, i.e. Proteobacteria, Firmicutes, Enterobacteriaceae, and all-bacteria, as well as specific genera and species, i.e. Acinetobacter, Burkholderia, Vibrio, Pseudomonas, Escherichia coli, and Staphylococcus, were developed and validated by considering a new mechanistic approach to simulate hybridization between the probe and the RNA. |
