[Ed. note (June 2019)--compiled from PI's technical progess report covering work done through February 2019]
Our overriding hypothesis is that exposure of C. albicans to microgravity will alter gene expression and morphology, consistent with a potential increase in virulence. More specifically, we suggest that diminished fluid shear results in alterations to the physical environment that contribute, directly or indirectly, to adaptations in the yeast cell surface resulting in increased virulence. Notably, these studies will further explore and document the genotypic and phenotypic parameters of C. albicans associated with pathogenicity, identify specific environmental influences on the physiological adaptation processes, and provide insight into mechanisms used by higher eukaryotes when adapting to spaceflight conditions.
Objectives/Aims of Investigation
• Evaluate the microgravity-induced alterations in biosynthetic regulation, cellular content, and subcellular localization of ergosterol and b-glucans.
• Delineate the contributions of fluid shear, oxygen depletion, and carbon dioxide enrichment in the microenvironment to cellular adaptation responses.
• Characterize the effect of spaceflight on C. albicans virulence using a human monocyte host.
The experiments included in the payload that flew on Space X CRS-16 specifically addressed Aim #2 (internally the payload is being referred to Micro-14alpha). Additional experiments flew on Space X CRS-17 and will address the other aims listed above (Micro-14beta). Initial reporting for both aspects of this payload will occur mid-summer 2019.
A full scale experiment verification test (EVT) (including all hardware components for the full Micro-14 payload) was initiated on 9/24/18 with BioServe Space Technologies personnel on site.
The 6-well BioCell and FEP (fluorinated ethylene-propylene) bag experiments were carried to completion as planned and on schedule. The Fluid Processing Apparatus (FPA) in experiments required some final adaptations.
Ultimately, each phase of the FPA experiment was completed, albeit with overlapping timelines. Selection for Flight permission was granted on 11/14/18, with some reservations due to the compartmentalized nature of the FPA EVT.
FPA loading spanned 11/29/18 (L-5) through 12/1/18 (L-3, including a reload of one condition – N2). FPAs were handed over to BioServe on 12/2/18 at 8 am for incorporation into Group Activation Packs (GAP). GAPs were turned over to CMC on 12/3/18 at 8 am. Launch was delayed 24 hrs to 12/5/18 at 1:16 pm, without implications for the Micro-14a payload.
Spaceflight time line -- all ground controls were conducted with a 1-hr offset based on real time communication with BioServe. Ground GAPs were stored on the horizontal and rotated 180° daily. When at 30°C, the ground GAPs were laid on the horizontal and very slowly rocked length wise.