Volumen 5 (2017): Edición 1 (July 2017)

Spaceflight is known to affect immune cell populations. In particular, splenic B-cell numbers decrease during spaceflight and in ground-based physiological models. Although antibody isotype changes have been assessed during and after spaceflight, an extensive characterization of the impact of spaceflight on antibody composition has not been conducted in mice. Next Generation Sequencing and bioinformatic tools are now available to assess antibody repertoires. We can now identify immunoglobulin gene-segment usage, junctional regions, and modifications that contribute to specificity and diversity. Due to limitations on the International Space Station, alternate sample collection and storage methods must be employed. Our group compared Illumina MiSeq^® sequencing data from multiple sample preparation methods in normal C57Bl/6J mice to validate that sample preparation and storage would not bias the outcome of antibody repertoire characterization. In this report, we also compared sequencing techniques and a bioinformatic workflow on the data output when we assessed the IgH and Igκ variable gene usage. Our bioinformatic workflow has been optimized for Illumina HiSeq^® and MiSeq^® datasets, and is designed specifically to reduce bias, capture the most information from Ig sequences, and produce a data set that provides other data mining options.

The first Veggie plant growth chamber was installed on the International Space Station in 2014. Crop plants can be grown in Veggie using plant pillows, small rooting packets that contain substrate, fertilizer, and germination wicks along with attached seeds. The pillows were designed to interface with the Veggie root mat reservoir watering system to provide a capillary water column to growing plants. In preparation for flight, methods of arcillite substrate washing, autoclaving, and drying were established to reduce dust and to provide a dry sterile substrate. A controlled released fertilizer mixed into arcillite substrate provides nutrition for plant growth. Methods of seed surface sterilization were tested for both germination and microbial contamination, and the optimum methods were determined for candidate flight crops. Plant pillows were prepared for flight by cutting and inserting germination wicks, filling with the substrate/fertilizer mix, and sewing closed. Following pillow filling, seeds were attached to the wicks, and the pillows were packaged for flight. Pillow preparation methods have been successfully tested in the VEG-01 hardware validation tests on the International Space Station with ‘Outredgeous’ lettuce and ‘Profusion’ zinnia, and in the VEG-03 test, using ‘Outredgeous’ lettuce and ‘Tokyo bekana’ Chinese cabbage.

Injecting a liquid into a gas-filled vessel while in weightlessness can result in at least two conditions–a droplet attached to the wall around the injection orifice and a geyser in which the liquid propagates away from the orifice in a continuous jet. The need to design injection of liquid to accomplish one condition or the other shows up in both zero-g fluids research geometries and spaceflight systems. Previous experiments by others assumed the rim of the injection orifice to be sharp. Liquid flow out of orifices with chamfered and rounded rims during the weightlessness of parabolic aircraft flight are studied in this work. When compared to previous work, results indicate that chamfered and rounded rims have little effect on the value of Weber number dividing the wall-bound droplet and geyser behaviors. Because any manufactured orifice will have finite bluntness, this conclusion is useful for both research and spaceflight systems.

Lower leg exercises are impacted by the anatomy of the triceps surae-Achilles tendon complex. Such exercises may utilize series elastic energy (SEE), temporarily stored within the Achilles tendon, to augment forces exerted by the triceps surae. While SEE's contribution to bipedal jumping and walking have been assessed, other lower leg exercises yet to receive similar scrutiny include seated calf presses done on flywheel-based hardware. Current subjects did two identical calf press workouts on a flywheel ergometer. The following three variables were obtained from workouts–the total work (TW) performed, net energy costs, and peak blood lactate concentration ([BLa⁻]). With multivariate regression, four variables correlated with each criterion measures’ variance–lower leg length (LLL) and cross-sectional area (CSA), as well as the lengths of the triceps surae (ML) and Achilles tendon (ATL). Our predictor variables correlated to significant amounts of TW and net energy cost, but not [BLa⁻] variance. Univariate matrices showed CSA was the best overall predictor for our criterion measures, while ML and ATL were generally weaker correlates. ATL did not have as great an impact as with other lower leg exercises; likely because the slow rate of ankle joint movement greatly limited SEE activity. The limited degree of foot support for ergometer repetitions was also a factor that likely weakened ATL's impact as a correlate. More research on anatomy's impact on this novel form of exercise is warranted.

Despite centuries of scientific balloon flights, only a handful of experiments have produced biologically relevant results. Yet unlike orbital spaceflight, it is much faster and cheaper to conduct biology research with balloons, sending specimens to the near space environment of Earth's stratosphere. Samples can be loaded the morning of a launch and sometimes returned to the laboratory within one day after flying. The National Aeronautics and Space Administration (NASA) flies large unmanned scientific balloons from all over the globe, with missions ranging from hours to weeks in duration. A payload in the middle portion of the stratosphere (~35 km above sea level) will be exposed to an environment similar to the surface of Mars—temperatures generally around −36°C, atmospheric pressure at a thin 1 kPa, relative humidity levels <1%, and harsh illumination of ultraviolet (UV) and cosmic radiation levels (about 100 W/m² and 0.1 mGy/d, respectively)—that can be obtained nowhere else on the surface of the Earth, including environmental chambers and particle accelerator facilities attempting to simulate space radiation effects. Considering the operational advantages of ballooning and the fidelity of space-like stressors in the stratosphere, researchers in aerobiology, astrobiology, and space biology can benefit from balloon flight experiments as an intermediary step on the extraterrestrial continuum (i.e., ground, low Earth orbit, and deep space studies). Our review targets biologists with no background or experience in scientific ballooning. We will provide an overview of large balloon operations, biology topics that can be uniquely addressed in the stratosphere, and a roadmap for developing payloads to fly with NASA.