We have investigated the effect of microgravity during spaceflight on body-wall muscle fiber size and muscle proteins in the paramyosin mutant of Caenorhabditis elegans. Both mutant and wild-type strains were subjected to 10 days of microgravity during spaceflight and compared to ground control groups. No significant change in muscle fiber size or quantity of the protein was observed in wild-type worms; where as atrophy of body-wall muscle and an increase in thick filament proteins were observed in the paramyosin mutant unc-15(e73) animals after spaceflight. We conclude that the mutant with abnormal muscle responded to microgravity by increasing the total amount of muscle protein in order to compensate for the loss of muscle function.
Research Containing: Spaceflight
In an effort to speed the rate of discovery in space biology and medicine NASA introduced the now defunct model specimen program. Four nations applied this approach with Caenorhabditis elegans in the ICE-FIRST experiment. Here we review the standardized culturing as well as the investigation of muscle adaptation, space biology radiation, and gene expression in response to spaceflight. Muscle studies demonstrated that decreased expression of myogenic transcription factors underlie the decreased expression of myosin seen in flight, a response that would appear to be evolutionarily conserved. Radiation studies demonstrated that radiation damaged cells should be able to be removed via apoptosis in flight, and that C. elegans can be employed as a biological accumulating dosimeter. Lastly, ICE-FIRST gave us our first glimpse at the genomic response to spaceflight, suggesting that altered Insulin and/or TGF-beta signaling in flight may underlie many of the biological changes seen in response to spaceflight. The fact that the results obtained with C. elegans appear to have strong similarities in human beings suggests that not only will C. elegans prove an invaluable model for understanding the fundamental biological changes seen during spaceflight but that it may also be invaluable for understanding those changes associated with human health concerns in space.
Analysis of possible causes of activation of gastric and the pancreatic excretory and incretory function after completion of space flight at the international space station
A comparative analysis of the excretory and incretory activity of the stomach and pancreas in astronauts soon after completion of space flights of various durations was performed. An increase in the fasting activity of gastric and pancreatic enzymes and hormones (insulin and C-peptide) in blood, reflecting the increased excretory and incretory activity of organs of the gastroduodenal region developing in microgravity, was demonstrated. The absence of subjects infected with Helicobacter pylori in the space flight crew excluded the involvement of this microorganism in the mechanism underlying the increase in the gastric secretory activity. The absence of correlation between the increase in the secretory activity of organs of the gastroduodenal region and the duration of the space flight allowed us to rule out the hypokinetic mechanism, which is associated with the duration of exposure to microgravity. It was concluded that the main mechanism underlying the changes in the functional state of the digestive system in space flight may be determined by the rearrangement of the venous hemodynamics of organs of the abdominal cavity, unrelated to the duration of exposure to microgravity. It was shown that, after completion of space flights and in ground-based experiments simulating the hemodynamic rearrangement occurring in microgravity, the increase in the basal excretory activity of gastroduodenal organs was not caused by gastrin secretion and occurred simultaneously with an increase in the secretion of insulin, which is considered as a putative hormonal component of the hemodynamic mechanism.
The present suite of advanced space plant cultivation facilities require a significant level of resources to launch and maintain in flight. The facilities are designed to accommodate a broad size range of plant species and are, therefore, not configured to support the specific growth requirements of small plant species such as Arabidopsis thaliana at maximum efficiency with respect to mass and power. The facilities are equally not configured to support automated plant harvesting or tissue processing procedures, but rely on crew intervention and time. The recent reorganization of both spaceflight opportunities and allocation of limited in-flight resources demand that experiments be conducted with optimal efficiency. The emergence of A. thaliana as a dominant space flight model organism utilized in research on vegetative and reproductive phase biology provides strong justification for the establishment of a dedicated cultivation system for this species. This paper presents work on the design of a small plant cultivation facility directed at supporting research on the vegetative growth phase of A. thaliana . The design of the facility is based on the use of existing space flight hardware, and configured to support the fully automated germination of seed, cultivation of plants, and final termination of plant growth by chemical fixation and preservation of plant tissue.
Constraints in both launch opportunities and the availability of in-flight resources for Shuttle and Space Station life science habitat facilities has presented a compelling impetus to improve the operational flexibility, efficiency and miniaturization of many of these systems. Such advances would not only invigorate the level of research being conducted in low Earth orbit but also present the opportunity to expand life science studies to outer space and planetary bodies. Work has been directed towards the development of a miniature plant cultivation module (PCM) capable of supporting the automated and controlled growth and spectral monitoring of small plant species such as Arabidopsis thaliana. This paper will present data on the operational performance and efficiency of the cultivation module, and the extent to which such a system may be used to support plant growth studies in low Earth orbit and beyond.
Loss of parafollicular cells during gravitational changes (microgravity, hypergravity) and the secret effect of pleiotrophin
It is generally known that bone loss is one of the most important complications for astronauts who are exposed to long-term microgravity in space. Changes in blood flow, systemic hormones, and locally produced factors were indicated as important elements contributing to the response of osteoblastic cells to loading, but research in this field still has many questions. Here, the possible biological involvement of thyroid C cells is being investigated. The paper is a comparison between a case of a wild type single mouse and a over-expressing pleiotrophin single mouse exposed to hypogravity conditions during the first animal experiment of long stay in International Space Station (91 days) and three similar mice exposed to hypergravity (2Gs) conditions. We provide evidence that both microgravity and hypergravity induce similar loss of C cells with reduction of calcitonin production. Pleiotrophin over-expression result in some protection against negative effects of gravity change. Potential implication of the gravity mechanic forces in the regulation of bone homeostasis via thyroid equilibrium is discussed.
Observing the mouse thyroid sphingomyelin under space conditions: a case study from the MDS mission in comparison with hypergravity conditions
This is a case report of apparent thyroid structural and functional alteration in a single mouse subjected to low Earth orbit spaceflight for 91 days. Histological examination of the thyroid gland revealed an increase in the average follicle size compared to that of three control animals and three animals exposed to hypergravity (2g) conditions. Immunoblotting analysis detected an increase in two thyroid gland enzymes, sphingomyelinase and sphingomyelin-synthase1. In addition, sphingomyelinase, an enzyme confined to the cell nucleus in the control animals, was found in the mouse exposed to hypogravity to be homogeneously distributed throughout the cell bodies. It represents the first animal observation of the influence of weightlessness on sphingomyelin metabolism.
Heart rate variability during centrifugation in astronauts prior to and after long duration spaceflight: Preliminary data
Spaceflight is known to induce vestibular and cardiovascular deconditioning. The current ESA SPIN project conducts research on vestibular and cardiovascular deconditioning after long duration spaceflight. Hereto, vestibular function and cardiovascular parameters are evaluated during centrifugation and during a tilt test in astronauts prior to and after spaceflight. The experiments are conducted using the ‘Visual and Vestibular Investigation System’. During rotation, cardiovascular and breathing parameters are recorded by means of the ‘Lifeshirt® system’ (Vivonoetics). The current analysis focuses on the cardio-respiratory response during 2 consecutive centrifugation runs, a counter clockwise (CCW) and a clockwise (CW). The RR-interval recorded postflight during the second CW rotation decreased significantly compared to the preflight data. No significant effects were observed on the parameters (amplitude, marker of vagal activity, and phase) of the respiratory sinus arrhythmia (RSA). However, the time of respiration and the amplitude of the RSA were correlated. Our preliminary results suggest a postflight recovery problem of the sympathetic nervous system after activation and show that the respiration has a large influence on the RSA amplitude.
TL dose measurements on board the Russian segment of the ISS by the “Pille” system during Expedition-8, -9 and -10
The “Pille-MKS” thermoluminescent (TL) dosimeter system developed by the KFKI Atomic Energy Research Institute (KFKI AEKI) and BL-Electronics, consisting of 10 CaSO 4 :Dy bulb dosimeters and a compact reader, has been continuously operating on board the International Space Station (ISS) since October 2003. The dosimeter system is utilized for routine and extravehicular activity (EVA) individual dosimetry of astronauts/cosmonauts as part of the service system as well as for on board experiments, and is operated by the Institute for Biomedical Problems (IBMP). The system is unique in that it regularly provides accurate dose data right on board the space station, a feature that became increasingly important during the suspension of the Space Shuttle flights. Seven dosimeters are located at different places of the Russian segment of the ISS and are read out once a month. Two of these dosimeters are dedicated to EVAs and one is kept in the reader and will be read out automatically every 90 min. During coronal mass ejections impacting Earth some of the dosimeters serve for individual monitoring of the astronauts with readouts once or twice every day. In this paper we report the results of dosimetric measurements made on board the ISS during Expedition-8, -9 and -10 using the “Pille” portable thermoluminescent detector (TLD) system and we compare them with our previous measurements on different space stations.
An understanding of the various source of non-methane volatile organic compounds is one facet to ensuing the habitability of crewed spacecraft. Although the International Space Station (ISS) atmosphere is relatively well characterized in terms of what is in it and approximately how much, linking the majority of these trace contaminants detected to their source is virtually impossible. Albeit a few of the trace contaminants can be associated to a single source, the majority have their origins from multiple sources. On crewed spacecraft such as ISS, trace contaminants are broadly categorized as either coming from equipment, which includes systems and payloads, or from the metabolic process of the crew members. Such widely encompassing categories clearly illustrate the difficulty in linking air contaminants to their source(s). It is well known that microbial growth in ISS can flourish if left unchecked. Although processes are in place to limit microbial growth, in reality, it has pervaded the habitable environment of ISS. This is simply a consequence of having crewed spacecraft, as humans are the largest contributor to the bioload. As with crew members, microbes also have metabolic processes that, in many ways are comparable to human metabolism. As such, it can be expectant that microbial growth can lead to the release of cortile organic compounds (VOCs) into the ISS atmosphere. Given a large enough microbial population, the impact to the air quality of ISS can be potentially large. A survey of the microbiology found in ISS will be presented here as well as the possible types of VOCs that can result from such organisms. This will be correlated to the observation provided by ground-based analysis of ISS atmosphere samples.