Kennedy Space Center

About: Kennedy Space Center is a facility organization based out in Merritt Island, Florida, United States. It is known for research contribution in the topics: In situ resource utilization & Space Shuttle. The organization has 1495 authors who have published 2591 publications receiving 41385 citations. The organization is also known as: John F. Kennedy Space Center, KSC & KSC.

Analytical approaches to the characterization of samples of microbial communities using patterns of potential C source utilization.

Abstract: Profiles of potential utilization of 95 separate C sources by microbial communities can be readily generated from direct incubation of environmental samples in BIOLOG microplates. Color formation from a redox indicator dye is used to quantify the degree of C source utilization. I aimed to examine different analytical approaches for classifying microbial communities based on these profiles. Specifically, the relative effects of average rate of color development versus the pattern of relative C source utilization on the classification of rhizosphere samples from different crop types were evaluated. The average rate of color development was correlated to the density of total (acridine-orange) bacterial cells (R2 = 0.52) and active (5-cyano-2,3-ditolyl tetrazolium chloride) bacterial cells (R2 = 0.70) inoculated into the plate. Analysis of plates with different rates of color development after a specific incubation period resulted in samples with variation in the overall extent of color development (expressed as average well color development, or AWCD). Classification of these samples using principal component analysis was significantly influenced by the variation in AWCD, resulting in the classification of samples based on the density of inoculum rather than the pattern of C source utilization. The effect of variation in AWCD was eliminated by normalizing data prior to ordination, or by using an alternative ordination technique, detrended correspondence analysis. Variation in AWCD can be limited through multiple-plate readings and subsequent selection of plates with a common reference point in AWCD. The specific AWCD used for analysis does not appear important for classification purposes; consistent discrimination of rhizosphere samples from different crop types was apparent for analysis across a wide range of AWCD (0.25–1.00 abs. units). The specific differences in C source utilization between rhizosphere sample types did depend on the set point used for analysis due to the differences in the rate of color formation among wells. Results suggest that single-plate readings can be used to classify samples, but only if potential differences in AWCD are accounted for in the data analysis. Repeated plate readings will provide a more complete understanding of differences in C source utilization among samples.

Blood volume: its adaptation to endurance training.

Abstract: Expansion of blood volume (hypervolemia) has been well documented in both cross-sectional and longitudinal studies as a consequence of endurance exercise training. Plasma volume expansion can account for nearly all of the exercise-induced hypervolemia up to 2-4 wk; after this time expansion may be distributed equally between plasma and red cell volumes. The exercise stimulus for hypervolemia has both thermal and nonthermal components that increase total circulating plasma levels of electrolytes and proteins. Although protein and fluid shifts from the extravascular to intravascular space may provide a mechanism for rapid hypervolemia immediately after exercise, evidence supports the notion that chronic hypervolemia associated with exercise training represents a net expansion of total body water and solutes. This net increase of body fluids with exercise training is associated with increased water intake and decreased urine volume output. The mechanism of reduced urine output appears to be increased renal tubular reabsorption of sodium through a more sensitive aldosterone action in man. Exercise training-induced hypervolemia appears to be universal among most animal species, although the mechanisms may be quite different. The hypervolemia may provide advantages of greater body fluid for heat dissipation and thermoregulatory stability as well as larger vascular volume and filling pressure for greater cardiac stroke volume and lower heart rates during exercise.

Space flight alters bacterial gene expression and virulence and reveals a role for global regulator Hfq

Abstract: A comprehensive analysis of both the molecular genetic and phenotypic responses of any organism to the space flight environment has never been accomplished because of significant technological and logistical hurdles. Moreover, the effects of space flight on microbial pathogenicity and associated infectious disease risks have not been studied. The bacterial pathogen Salmonella typhimurium was grown aboard Space Shuttle mission STS-115 and compared with identical ground control cultures. Global microarray and proteomic analyses revealed that 167 transcripts and 73 proteins changed expression with the conserved RNA-binding protein Hfq identified as a likely global regulator involved in the response to this environment. Hfq involvement was confirmed with a ground-based microgravity culture model. Space flight samples exhibited enhanced virulence in a murine infection model and extracellular matrix accumulation consistent with a biofilm. Strategies to target Hfq and related regulators could potentially decrease infectious disease risks during space flight missions and provide novel therapeutic options on Earth.