Raman Spectroscopic Analysis of Cupriavidus metallidurans LMG 1195 (CH34) Cultured in Low-shear Microgravity Conditions

Abstract

In this study, the effect of low-shear microgravity on the metabolism of Cupriavidus metallidurans LMG 1195 was studied with Raman spectroscopy. Therefore, the strain was cultured for 24 or 48 h in a rotating wall vessel to simulate microgravity (SMG) and in a control setup. The differences in Raman spectra recorded from both setups after 24 h of culturing were small. The most prominent features in a difference spectrum, calculated between the mean spectra from the microgravity and the control setup separately, could be assigned to the presence of poly-β-hydroxybutyrate (PHB). SMG seems to yield a higher PHB production after 24 h of culturing. Additional processing of the spectra suggested that SMG induced also other changes in the carbon metabolism. After 48 h, similar results were found for the carbon metabolism, while PHB concentrations were reduced in SMG compared to the control. However, these differences could also be caused by interfering effects that may occur in the bioreactors after a prolonged incubation time.

The Complete Genome Sequence of Cupriavidus metallidurans Strain CH34, a Master Survivalist in Harsh and Anthropogenic Environments

“…Interestingly, PHB synthesis in CH34 is initially (i.e., after 24 hours of growth) enhanced under simulated microgravity [41]. The CH34 genome has three copies of phaC , one copy each of phaA and phaP , three copies of phaB , and one regulatory gene phaR (for Rmet numbers see Table S9).…”

“…In addition, we have noted changes in gene expression, cell morphology and physiology for C. metallidurans CH34 cells in response to spaceflight (i.e. cells grown at the International Space Station during 10-day visits) and oxidative stress [41] , [42] , as well as simulated microgravity and ionizing radiation (unpublished). The organism has been isolated from very harsh environments such as ultra-clean spacecraft assembly rooms [43] and spent-nuclear-fuel pools [44] .…”

Effects of spaceflight and simulated microgravity on microbial growth and secondary metabolism

“…In the study of De Gelder et al [ 21 ], the yield of poly-β-hydroxybutyrate (PHB) produced by Cupriavidus metallidurans LMG 1195 under LSSMG conditions in the RWVs was reported to be increased after 24 h of culture, while after 48 h of culture, the PHB concentrations were reduced in SMG compared to in the control. In the study of Benoit et al [ 5 ], the production of actinomycin D by Streptomyces plicatus WC56452 in space was reported to be increased by 15.6 and 28.5% on days 8 and 12, respectively, but decreased in all subsequent matched sample points (16–72 d at intervals of 4 d) compared to the ground controls.…”

“…However, the different mechanisms by which they respond and adapt to these environments (especially to microgravity in space) remain unclear. Recently, spaceflight and ground simulated microgravity (SMG) or low-shear modeled microgravity (LSMMG) experiments have demonstrated that microgravity can affect cellular processes and functions in microorganisms, such as cell growth [ 6 – 9 ], gene expression [ 10 – 12 ], cell morphology and development [ 13 , 14 ], virulence and resistance [ 15 – 18 ], biofilm formation [ 19 , 20 ], secondary metabolism [ 21 – 23 ], and microbial mutations and relation to adaptation to LSMMG [ 24 ]. Considerable effort has been focused on cell growth and secondary metabolism.…”

How the space environment influences organisms: an astrobiological perspective and review

“…de Gelder et al . (2009) demonstrated increased production of poly-β-hydroxybutyrate by C. metallidurans LMG 1195 after 24 h of cultivation under LSSMG conditions but reduction after 48 h of culture compared to 1 × g controls, indicating fluctuation of metabolite production in microgravity. No simulated-microgravity-related changes in the production of secondary metabolites (e.g.…”