Projecting a vision for space radiobiological research necessitates understanding the nature of the space radiation environment and how radiation risks influence mission planning, timelines and ...operational decisions. Exposure to space radiation increases the risks of astronauts developing cancer, experiencing central nervous system (CNS) decrements, exhibiting degenerative tissue effects or developing acute radiation syndrome. One or more of these deleterious health effects could develop during future multi-year space exploration missions beyond low Earth orbit (LEO). Shielding is an effective countermeasure against solar particle events (SPEs), but is ineffective in protecting crew members from the biological impacts of fast moving, highly-charged galactic cosmic radiation (GCR) nuclei. Astronauts traveling on a protracted voyage to Mars may be exposed to SPE radiation events, overlaid on a more predictable flux of GCR. Therefore, ground-based research studies employing model organisms seeking to accurately mimic the biological effects of the space radiation environment must concatenate exposures to both proton and heavy ion sources. New techniques in genomics, proteomics, metabolomics and other "omics" areas should also be intelligently employed and correlated with phenotypic observations. This approach will more precisely elucidate the effects of space radiation on human physiology and aid in developing personalized radiological countermeasures for astronauts.
This review article is a compendium of six individual manuscripts, a Commentary, and an Executive Summary. This body of work is entitled "The Impact of Sex and Gender on Adaptation to Space" and was ...developed in response to a recommendation from the 2011 National Academy of Sciences Decadal Survey, "Recapturing a Future for Space Exploration: Life and Physical Sciences for a New Era," which emphasized the need to fully understand sex and gender differences in space. To ensure the health and safety of male and female astronauts during long-duration space missions, it is imperative to examine and understand the influences that sex and gender have on physiological and psychological changes that occur during spaceflight. In this collection of manuscripts, six workgroups investigated and summarized the current body of published and unpublished human and animal research performed to date related to sex- and gender-based differences in the areas of cardiovascular, immunological, sensorimotor, musculoskeletal, reproductive, and behavioral adaptations to human spaceflight. Each workgroup consisted of scientists and clinicians from academia, the National Aeronautics and Space Administration (NASA), and other federal agencies and was co-chaired by one representative from NASA and one from the external scientific community. The workgroups met via telephone and e-mail over 6 months to review literature and data from space- and ground-based studies to identify sex and gender factors affecting crew health. In particular, the Life Sciences Data Archive and the Lifetime Surveillance of Astronaut Health were extensively mined. The groups identified certain sex-related differences that impact the risks and the optimal medical care required by space-faring women and men. It represents innovative research in sex and gender-based biology that impacts those individuals that are at the forefront of space exploration.
Managing coral reefs for resilience to climate change is a popular concept but has been difficult to implement because the empirical scientific evidence has either not been evaluated or is sometimes ...unsupportive of theory, which leads to uncertainty when considering methods and identifying priority reefs. We asked experts and reviewed the scientific literature for guidance on the multiple physical and biological factors that affect the ability of coral reefs to resist and recover from climate disturbance. Eleven key factors to inform decisions based on scaling scientific evidence and the achievability of quantifying the factors were identified. Factors important to resistance and recovery, which are important components of resilience, were not strongly related, and should be assessed independently. The abundance of resistant (heat-tolerant) coral species and past temperature variability were perceived to provide the greatest resistance to climate change, while coral recruitment rates, and macroalgae abundance were most influential in the recovery process. Based on the 11 key factors, we tested an evidence-based framework for climate change resilience in an Indonesian marine protected area. The results suggest our evidence-weighted framework improved upon existing un-weighted methods in terms of characterizing resilience and distinguishing priority sites. The evaluation supports the concept that, despite high ecological complexity, relatively few strong variables can be important in influencing ecosystem dynamics. This is the first rigorous assessment of factors promoting coral reef resilience based on their perceived importance, empirical evidence, and feasibility of measurement. There were few differences between scientists' perceptions of factor importance and the scientific evidence found in journal publications but more before and after impact studies will be required to fully test the validity of all the factors. The methods here will increase the feasibility and defensibility of including key resilience metrics in evaluations of coral reefs, as well as reduce costs. Adaptation, marine protected areas, priority setting, resistance, recovery.
There is a substantial list of pre‐analytical variables that can alter the analysis of blood‐derived samples. We have undertaken studies on some of these issues including choice of sample type, ...stability during storage, use of protease inhibitors, and clinical standardization. As there is a wide range of sample variables and a broad spectrum of analytical techniques in the HUPO PPP effort, it is not possible to define a single list of pre‐analytical standards for samples or their processing. We present here a compendium of observations, drawing on actual results and sound clinical theories and practices. Based on our data, we find that (1) platelet‐depleted plasma is preferable to serum for certain peptidomic studies; (2) samples should be aliquoted and stored preferably in liquid nitrogen; (3) the addition of protease inhibitors is recommended, but should be incorporated early and used judiciously, as some form non specific protein adducts and others interfere with peptide studies. Further, (4) the diligent tracking of pre‐analytical variables and (5) the use of reference materials for quality control and quality assurance, are recommended. These findings help provide guidance on sample handling issues, with the overall suggestion being to be conscious of all possible pre‐analytical variables as a prerequisite of any proteomic study.
To understand the health impact of long-duration spaceflight, one identical twin astronaut was monitored before, during, and after a 1-year mission onboard the International Space Station; his twin ...served as a genetically matched ground control. Longitudinal assessments identified spaceflight-specific changes, including decreased body mass, telomere elongation, genome instability, carotid artery distension and increased intima-media thickness, altered ocular structure, transcriptional and metabolic changes, DNA methylation changes in immune and oxidative stress-related pathways, gastrointestinal microbiota alterations, and some cognitive decline postflight. Although average telomere length, global gene expression, and microbiome changes returned to near preflight levels within 6 months after return to Earth, increased numbers of short telomeres were observed and expression of some genes was still disrupted. These multiomic, molecular, physiological, and behavioral datasets provide a valuable roadmap of the putative health risks for future human spaceflight.
The United States first sent humans into space during six flights of Project Mercury from May 1961 to May 1963. These flights were brief, with durations ranging from about 15 min to just over 34 h. A ...primary purpose of the project was to determine if humans could perform meaningful tasks while in space. This was supported by a series of biomedical measurements on each astronaut before, during (when feasible), and after flight to document the effects of exposure to the spaceflight environment. While almost all of the data presented here have been published in technical reports, this is the first integrated summary of the main results. One unexpected finding emerges: the major physiological changes associated with these short-term spaceflights are correlated more strongly with time spent by the astronaut in a spacesuit than with time spent in space per se. Thus, exposure to the direct stressors of short-duration (up to 34 h) spaceflight was not the dominant factor influencing human health and performance. This is relevant to current spaceflight programs and especially to upcoming commercial flights in which time spent in space (as on a suborbital flight) will be minor compared to the time spent in associated preparation, ascent, and return.
We present an approach called pulsed multiline excitation (PME) for measurements of multicomponent, fluorescence species and demonstrate its application in capillary electrophoresis for DNA ...sequencing. To fully demonstrate the advantages of PME, a fluorescent dye set has been developed whose absorption maxima span virtually the entire visible spectrum. Unlike emission wavelength-dependent approaches for identifying fluorescent species, the removal of the spectral component in PME confers a number of advantages including higher and normalized signals from all dyes present in the assay, the elimination of spectral cross-talk between dyes, and higher signal collection efficiency. Base-calling is unambiguously determined once dye mobility corrections are made. These advantages translate into significantly enhanced signal quality as illustrated in the primary DNA sequencing data and provide a means for achieving accurate base-calling at lower reagent concentrations.
Ensuring that proteolytic digestions are complete before submitting samples for downstream proteomic analyses is important, as failure or partial digestion can waste valuable instrument time and make ...results difficult to interpret. Conversely, overdigestion can also be problematic, such as when removing affinity tags from recombinant proteins or using nonspecific proteases. The techniques of HPLC, circular dichroism, SDS-PAGE, and MS have each been used to assess protein digestion. These techniques are slow, may require expensive instrumentation, can be inaccurate, and/or are unsuitable for real-time monitoring. Epicocconone is a natural fluorophore that reacts reversibly with proteins to form a highly fluorescent adduct and has previously been used to quantify proteins in 1D and 2D gels and in solution. Here, we describe a new method for the real-time monitoring of protein digestion based on epicocconone. This unique in situ fluorescent assay can tracelessly follow proteolysis of samples, at low microgram levels, destined for proteomics analysis or purification.
The pathogenic form of the cyclooxygenase (COX) enzyme, COX-2, is also constitutively present in the spinal cord and has been implicated in chronic pain states in rat and man. A number of COX-2 ...inhibitors, including celecoxib and rofecoxib, are already used in man for the treatment of inflammatory pain. Preclinically, the dual-acting COX-2 inhibitor, GW406381X 2-(4-ethoxyphenyl)-3-4-(methylsulfonyl)phenyl-pyrazolo1,5-bpyridazine, where X denotes the free base, is as effective as rofecoxib and celecoxib in the rat established Freund's Complete Adjuvant model with an ED(50) of 1.5 mg/kg p.o. compared with 1.0 mg/kg p.o. for rofecoxib and 6.6 mg/kg p.o. for celecoxib. However, in contrast to celecoxib (5 mg/kg p.o. b.i.d.) and rofecoxib (5 mg/kg p.o. b.i.d.), which were without significant effect, GW406381X (5 mg/kg p.o. b.i.d.) fully reversed mechanical allodynia in the chronic constriction injury model and reversed thermal hyperalgesia in the mouse partial ligation model, both models of neuropathic pain. GW406381X, was also effective in a rat model of capsaicin-induced central sensitization, when given intrathecally (ED(50) = 0.07 mug) and after chronic but not acute oral dosing. Celecoxib and rofecoxib had no effect in this model. Several hypotheses have been proposed to try to explain these differences in efficacy, including central nervous system penetration, enzyme kinetics, and potency. The novel finding of effectiveness of GW406381X in these models of neuropathic pain/central sensitization, in addition to activity in inflammatory pain models and together with its central efficacy, suggests dual activity of GW406381X compared with celecoxib and rofecoxib, which may translate into greater efficacy in a broader spectrum of pain states in the clinic.
The inclusion of protease inhibitors in serum or plasma samples has been found to significantly impact the isoform profile of selected plasma proteins as seen on 2-dimensional electrophoresis (2-DE) ...gels. With the addition of a protease inhibitor cocktail, several human plasma protein trains depleted of albumin and immunoglobulin G (IgG) exhibited higher isoelectric point (pI) isoforms. This shift was especially apparent for apolipoprotein A1 (apo A1), a relatively high abundance protein. The six protease inhibitor components of the cocktail were individually investigated with albumin and IgG depleted human plasma, and it was shown that the observed effects were caused by 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF), a serine protease inhibitor that covalently modifies proteins and/or peptides. Several serine-and/or tyrosine-containing peptides of apo A1 were modified with a concomitant mass increase of 183 Da, which is consistent with the mass increase expected following reaction with AEBSF. These modifications were observed with increasing propensity in the higher pI spots. An increase in both the number and proportion of modified peptides with increasing pI was also observed. A model is proposed for the random or stochastic coupling of AEBSF-derived moieties to serine and/or tyrosine residues throughout apo A1 and potentially other plasma proteins.
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