Simulated microgravity facilitates stomatal ingression by Salmonella in lettuce and suppresses a biocontrol agent.

As human spaceflight increases in duration, cultivation of crops in spaceflight is crucial to protecting human health under microgravity and elevated oxidative stress. Foodborne pathogens (e.g., Salmonella enterica) carried by leafy green vegetables are a significant cause of human disease. Our previous work showed that Salmonella enterica serovar Typhimurium suppresses defensive closure of foliar stomata in lettuce (Lactuca sativa L.) to ingress interior tissues of leaves. While there are no reported occurrences of foodborne disease in spaceflight to date, known foodborne pathogens persist aboard the International Space Station and space-grown lettuce has been colonized by a diverse microbiome including bacterial genera known to contain human pathogens. Interactions between leafy green vegetables and human bacterial pathogens under microgravity conditions present in spaceflight are unknown. Additionally, stomatal dynamics under microgravity conditions need further elucidation. Here, we employ a slow-rotating 2-D clinostat to simulate microgravity upon in-vitro lettuce plants following a foliar inoculation with S. enterica Typhimurium and use confocal microscopy to measure stomatal width in fixed leaf tissue. Our results reveal significant differences in average stomatal aperture width between an unrotated vertical control, plants rotated at 2 revolutions per minute (2 RPM), and 4 RPM, with and without the presence of S. typhimurium. Interestingly, we found stomatal aperture width in the presence of S. typhimurium to be increased under rotation as compared to unrotated inoculated plants. Using confocal Z-stacking, we observed greater average depth of stomatal ingression by S. typhimurium in lettuce under rotation at 4 RPM compared to unrotated and inoculated plants, along with greater in planta populations of S. typhimurium in lettuce rotated at 4 RPM using serial dilution plating of homogenized surface sterilized leaves. Given these findings, we tested the ability of the plant growth-promoting rhizobacteria (PGPR) Bacillus subtilis strain UD1022 to transiently restrict stomatal apertures of lettuce both alone and co-inoculated with S. typhimurium under rotated and unrotated conditions as a means of potentially reducing stomatal ingression by S. typhimurium under simulated microgravity. Surprisingly, rotation at 4 RPM strongly inhibited the ability of UD1022 alone to restrict stomatal apertures and attenuated its efficacy as a biocontrol following co-inoculation with S. typhimurium. Our results highlight potential spaceflight food safety issues unique to production of crops in microgravity conditions and suggest microgravity may dramatically reduce the ability of PGPRs to restrict stomatal apertures.

Leaf yield and mineral content of mizuna in response to cut-and-come-again harvest, substrate particle size, and fertilizer formulation in a simulated spaceflight environment.

The Veggie plant-growth unit deployed onboard the International Space Station (ISS) grows leafy vegetables to supplement crew diets. "Cut-and-come-again" harvests are tested to maximize vegetative yield while minimizing crew time. Water, oxygen, and fertilizer delivery to roots of leafy greens growing in microgravity have become the center of attention for Veggie. Current Veggie technology wicks water into particulate root substrates incorporating controlled-release fertilizer (CRF). Mizuna mustard (Brassica rapa) was grown under ISS-like environments in ground-based Veggie-analogue units comparing crop response to combinations of two different substrate particle sizes, two different fertilizer formulations, and three leaf-harvest times from each plant. Fine-particle porous ceramic substrate (Profile©) was compared with a 40:60 mix of fine-particle porous ceramic Profile© + coarse porous ceramic Turface© substrate. Identical 18-6-8 (NPK) CRF formulations consisting of [50% fast-release (T70) + 50% intermediate-release (T100) prills] vs. [50% fast-release (T70) + 50% slow-release (T180) prills] were incorporated into each substrate, and leaf tissues were harvested from each treatment combination at 28, 48, and 56 days after sowing. The combination of T100 CRF in 100% Profile© substrate gave the highest fresh mass (FM) and leaf area (LA) across harvests, whereas T180 CRF in 40% Profile© gave the lowest. Dry-mass (DM) yields varied with effects on leaf area. Tissue nitrogen (N) and potassium (K) specific contents declined across harvests for all treatment combinations but tended to be highest for T100 CRF/100% Profile©, and lowest for T180 CRF/40% Profile©. These major macronutrients were taken up faster by roots growing in small particle-size substrate incorporating intermediate-rate CRF, but also were depleted faster from the same treatment combination, suggesting it may not continue to be the best combination for additional harvests. Micronutrients did not decline in tissue specific content across treatment combinations, but manganese (Mn) accumulated in leaf tissue across treatments and apparently comes mainly from the ceramic substrate, regardless of particle size. Substrate leachate analysis following final harvest indicated that pH remained in the range for nominal availability of mineral nutrients for root uptake, but electro-conductivity measurements suggested depletion of fertilizer salts from root zones, especially from the treatment combination supporting the highest yields and major macronutrient contents. Although 100% Profile© was the better growth substrate for mizuna in combination with intermediate-rate CRF and three cut-and-come-again harvests in ground-based studies, mixed-particle-size substrates may be a better choice for plant growth under microgravity conditions, where capillary forces predominant and tend to cause saturation of a fine medium with water. Since there were no statistically significant interactions between substrate and fertilizer in this study, our ground-based findings for CRF choice should translate to the best substrate choice for microgravity, but if NASA wants to consider additional cut-and-come-again harvests from the same mizuna plants, more complex CRF formulations likely will have to be investigated.

Impact of Exercise-Induced Strains and Nutrition on Bone Mineral Density in Spaceflight and on the Ground.

BACKGROUND: Bone mineral density (BMD) is a measure of skeletal health that may foretell disorders like osteoporosis.METHODS: To reduce bone losses on Earth, treatments include exercise, diet, and drugs. Each impact osteoblast and osteoclast activity dictates skeletal remodeling and subsequent BMD changes. BMD loss is a concern during spaceflight. For astronauts, low BMD undermines in-flight tasks and compromises their postflight health.RESULTS: While bisphosphonates exhibited promise as an in-flight bone loss treatment, study results are mixed, and this class of drugs has numerous side-effects. While the role antiresorptive agents play in reducing BMD loss is discussed, this review focuses on exercise-induced strains and nutrition, two in-flight treatments without bisphosphonates' side-effects.DISCUSSION: Evidence supports in-flight exercise and a healthy diet with vitamin D and Ca+2 supplementation to limit BMD loss. This review suggests how exercise and nutrition may limit BMD loss during spaceflight. Also discussed is an in-flight version of the inertial exercise trainer (IET; Impulse Technologies, Knoxville TN). By imparting high bone-strain magnitudes, rates, and frequencies with less mass, footprint, and power needs than other forms of in-flight resistance exercise hardware, the IET warrants inquiry for use aboard future long-term spaceflights.Caruso J, Patel N, Wellwood J, Bollinger L. Impact of exercise-induced strains and nutrition on bone mineral density in spaceflight and on the ground. Aerosp Med Hum Perform. 2023; 94(12):923-933.

Effect of acupuncture at different time points on kidney function and oxygen free radical metabolism in rats with simulated weightlessness / 中国针灸

<p><b>OBJECTIVE</b>To explore the effects of pre-acupuncture and immediate acupuncture on kidney function and oxygen free radical metabolism in rats with simulated weightlessness.</p><p><b>METHODS</b>Twenty male clean-grade Wister rats were randomly divided into a normal control group, a model group, a pre-acupuncture group and an immediate acupuncture group, 5 rats in each one. The rats in the normal control group did not receive any treatment but free activities for 4 weeks. The rats in the rest groups received 4-week tail suspension to establish the model of simulated weightlessness. One week before the tail suspension, the rats in the pre-acupuncture group were treated with electroacupuncture at "Shenshu" (BL 23), "Pishu" (BL 20) and "Sanyinjiao" (SP 6) for 30 min per treatment, once a day for 7 days. The rats in the immediate acupuncture group received tail suspension and acupuncture at the same time; during the tail suspension, the electroacupuncture was applied at "Shenshu" (BL 23), "Pishu" (BL 20) and "Sanyinjiao" (SP 6) for 30 min per treatment, once every other day for 14 days. The colorimetric method was used to measure the content of blood urea nitrogen (BUN) in serum as well as activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) and content of malonaldehyde (MDA) in renal tissue in each group.</p><p><b>RESULTS</b>Compared with the normal control group, the content of BUN in the model group was increased significantly (P<0.01), the activity of SOD and GSH-PX in nephridial tissue was significantly reduced (both P<0.01), and the content of MDA was increased significantly (P<0.05). Compared with the model group, the content of BUN in the pre-acupuncture group and immediate acupuncture group was significantly reduced (P<0.01, P<0.05), the activity of GSH-PX in the pre-acupuncture group was obviously increased (P<0.05) and the content of MDA in the immediate acupuncture group was increased significantly (P<0.01). Compared with the immediate acupuncture group, the content of MDA in the pre-acupuncture group was lower (P<0.01).</p><p><b>CONCLUSION</b>The pre-acupuncture and immediate acupuncture both have the capacity to improve the kidney function and anti-oxygen free radical injury in rats with simulated weightlessness, however, the capacity to increase the protection ability of the kidney and eliminate free radical in the pre-acupuncture group is superior to that in the immediate acupuncture group, which is likely to be related with improving antioxidant ability of kidney.</p>

Research progress on mutation by spaceflight in medicinal plants breeding / 中国中药杂志

Space breeding in medicinal plants is special characteristics in China. Compared with other plants, in spite of a relatively small number, Medicinal plants have more obvious characteristics and advantages. Research on medicinal plants has also been carried into all aspects, such as biological traits, physiology and biochemistry, genomics, as well as differences in chemical composition, and chemical composition analysis is also involved. However, compared with other plants, especially crops and vegetables, biological research is an obvious deficiency, that is mainly reflected in the insufficient genetics and breeding researches, the stability of genetic traits from generation to generation were not followed up and in-depth study in breeding areas was not carried out. If medicinal plants resources from space with the genetic stability good quality were selected, it would address the problem of lack of resources and ease the pressure on wild resources of medicinal plants. It would at the same time play an important role in promoting the development of medicinal botany space breeding and the implementation of modernization of traditional Chinese medicine.

Effects of chemical constituent in roots of Achyranthes Bidentata / 中国中药杂志

The difference of ingredients between the roots from the SP1 plants of Achyranthes Bidentata carried by satellite and the control's were evaluated in this study. The techniques of ultraviolet-visible spectroscopy (UVS), infrared spectroscopy (IR), Xray diffraction (XRD) and SDS-PAGE were used to analyse the chemical constituent in the root of A. bidentata. The results demonstrated that the UVS, IR, XRD and protein fingerprints of the roots from A. bidentata were distinct with special characters. The difference of the IR, XRD and protein fingerprints could be discriminated the satellite plants roots from those of the control, however, there were no difference of the UVS fingerprints between the satellite plants roots and the control. This indicated that the kinds of chemical ingredients were not different between the two groups, but the contents of some chemical ingredients deceased in SP1 plants of A. bidentata carried by satellite.

Effects of L.F04, the active fraction of Lycopus lucidus, on erythrocytes rheological property / 中国结合医学杂志

<p><b>OBJECTIVE</b>To study the effects of L.F04, the active fraction of Lycopus lucidus, on erythrocytes rheological property so as to investigate its mechanism in promoting blood circulation and removing blood stasis.</p><p><b>METHOD</b>The effects of L.F04 (used for treatment for 10 days in different dosages) on deformability, aggregation and membrane liquidity of erythrocytes (MLE) as well as whole blood apparent viscosity (eta(b)) were examined on the basis of rat model of blood-stasis syndrome induced by venous injection of high molecular weight dextran.</p><p><b>RESULT</b>As compared with the normal control group, the model group's RBC deformability and MLE were lower, and the aggregation of erythrocytes and eta(b) were higher. Compared with the model group, both L.F04 0.612 g/kg and 0.306 g/kg showed significant effect in improving deformability and inhibiting aggregation of red blood cells (RBC) and reducing blood viscosity. The trend of improving MLE was also shown.</p><p><b>CONCLUSION</b>L.F04 could significantly improve the abnormal rheological property of erythrocytes.</p>

Utilization of spaceflight technology on medicinal plant study / 中国中药杂志

Utilization of spaceflight technology will benefit the modernization of Traditional Chinese Medicine study. Many countries, such as USA or Russia, have conducted extensive experimental research with plants in the regenerative life-support system in space stations as well as the research on breeding or chromosomal aberration after spaceflight. The space botany is still in its preliminary stage in our country. Research has mainly been focused on breeding under space-environment. In addition, many experiments have been conducted with the spaceflown plants to investigate the growth, development, biochemical and physiological changes, as well as the inheritance and variation. Little has been done with regard to the facility development to contain the spaceflying seeds and no research has been reported on plant growth in spacecrafts. Medicinal plant study has certain characteristics and advantages in our country where small biological vessels are developed for the spaceflown seeds, which are then distinguished to microgravity group and radiation exposed group with analytical instrument. However, research has been carried out in medicinal plant breeding or inheritance. In future research, more effort should be directed to the study of medicinal plants as an important link of a future biological life support system as well as to the health care of astronauts by.