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The interest in examining the subset of proteins present in the extracellular milieu, the exoproteome, has been growing due to novel insights highlighting their role on extracellular matrix organization and biofilm formation, but also on homeostasis and development. The cyanobacterial exoproteome is poorly studied, and the role of cyanobacterial exoproteins on cell wall biogenesis, morphology and even physiology is largely unknown. Here, we present a comprehensive examination of the Anabaena sp. PCC 7120 exoproteome under various growth conditions. Altogether, 139 proteins belonging to 16 different functional categories have been identified. A large fraction (48%) of the identified proteins is classified as "hypothetical", falls into the "other categories" set or presents no similarity to other proteins. The evidence presented here shows that Anabaena sp. PCC 7120 is capable of outer membrane vesicle formation and that these vesicles are likely to contribute to the exoproteome profile. Furthermore, the activity of selected exoproteins associated with oxidative stress has been assessed, suggesting their involvement in redox homeostasis mechanisms in the extracellular space. Finally, we discuss our results in light of other cyanobacterial exoproteome studies and focus on the potential of exploring cyanobacteria as cell factories to produce and secrete selected proteins. [ABSTRACT FROM AUTHOR]

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Human spaceflight is likely to change in character over the 21st century, shifting from a military/governmental enterprise to one that is more firmly tied to private industry, including businesses devoted to space tourism. For space tourism to become a reality, however, many obstacles have to be overcome, particularly those in finance, technology, and medicine. Ethnographic interviews with astronauts, engineers, NASA doctors, and NewSpace workers reveal that absolute faith in the eventual human occupation of space, based in religious conviction or taking secular forms, is a common source of motivation across different populations working to promote human spaceflight. This paper examines the way faith is expressed in these different contexts and its role in developing a future where space tourism may become commonplace. [ABSTRACT FROM AUTHOR]