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At least 451 records · Page 25

Pick-and-Eat Salad-Crop Productivity, Nutritional Value, and Acceptability to Supplement the ISS Food System

The capability to grow nutritious, palatable food for crew consumption during spaceflight has the potential to provide health-promoting, bioavailable nutrients, enhance the dietary experience, and reduce launch mass as we move toward longer-duration missions. However, studies of edible produce during spaceflight have been limited, leaving a significant knowledge gap in the methods required to grow safe, acceptable, nutritious crops for consumption in space. Researchers from Kennedy Space Center, Johnson Space Center, Purdue University and ORBITEC have teamed up to explore the potential for plant growth and food production on the International Space Station (ISS) and future exploration missions. KSC, Purdue, and ORBITEC bring a history of plant and plant-microbial interaction research for ISS and for future bioregenerative life support systems. JSC brings expertise in Advanced Food Technology (AFT), Behavioral Health and Performance (BHP), and statistics. The Veggie vegetable-production system on the ISS offers an opportunity to develop a pick-and-eat fresh vegetable component to the ISS food system as a first step to bioregenerative supplemental food production. We propose growing salad plants in the Veggie unit during spaceflight, focusing on the impact of light quality and fertilizer formulation on crop morphology, edible biomass yield, microbial food safety, organoleptic acceptability, nutritional value, and behavioral health benefits of the fresh produce. The first phase of the project will involve flight tests using leafy greens, with a small Chinese cabbage variety, Tokyo bekana, previously down selected through a series of research tests as a suitable candidate. The second phase will focus on dwarf tomato. Down selection of candidate varieties have been performed, and the dwarf cultivar Red Robin has been selected as the test crop. Four light treatments and three fertilizer treatments will be tested for each crop on the ground, to down select to two light treatments and one fertilizer treatment to test on ISS. Our work will help define light colors, levels, and horticultural best practices to achieve high yields of safe, nutritious leafy greens and tomatoes to supplement a space diet of prepackaged food. Our final deliverable will be the development of growth protocols for these crops in a spaceflight vegetable production system. With this work, and potentially with other pending joint projects, we will continue the synergistic research to help close gaps in the human research roadmap, and enable humans to venture to Mars and beyond. This research was co-funded by the Human Research Program and Space Biology (MTL1075) in the ILSRA 2015 NRA call.

Behavioral Health↗

Plant Biomass Leaching for Nutrient Recovery in Closed Loop Systems Project

Plants will be important for food and O2 production during long term human habitation in space. Recycling of nutrients (e.g., from waste materials) could reduce the resupply costs of fertilizers for growing these plants. Work at NASA's Kennedy Space Center has shown that ion exchange resins can extract fertilizer (plant essential nutrients) from human waste water, after which the residual brine could be treated with electrodialysis to recover more water and produce high value chemicals (e.g., acids and bases). In habitats with significant plant production, inedible biomass becomes a major source of solid waste. To "close the loop" we also need to recover useful nutrients and fertilizer from inedible biomass. We are investigating different approaches to retrieve nutrients from inedible plant biomass, including physical leaching with water, processing the biomass in bioreactors, changing the pH of leaching processing, and/or conducting multiple leaches of biomass residues.

Technology Portfolio System↗

Implications of Climate Mitigation for Future Agricultural Production

Climate change is projected to negatively impact biophysical agricultural productivity in much of the world. Actions taken to reduce greenhouse gas emissions and mitigate future climate changes, are thus of central importance for agricultural production. Climate impacts are, however, not unidirectional; some crops in some regions (primarily higher latitudes) are projected to benefit, particularly if increased atmospheric carbon dioxide is assumed to strongly increase crop productivity at large spatial and temporal scales. Climate mitigation measures that are implemented by reducing atmospheric carbon dioxide concentrations lead to reductions both in the strength of climate change and in the benefits of carbon dioxide fertilization. Consequently, analysis of the effects of climate mitigation on agricultural productivity must address not only regions for which mitigation is likely to reduce or even reverse climate damages. There are also regions that are likely to see increased crop yields due to climate change, which may lose these added potentials under mitigation action. Comparing data from the most comprehensive archive of crop yield projections publicly available, we find that climate mitigation leads to overall benefits from avoided damages at the global scale and especially in many regions that are already at risk of food insecurity today. Ignoring controversial carbon dioxide fertilization effects on crop productivity, we find that for the median projection aggressive mitigation could eliminate approximately 81% of the negative impacts of climate change on biophysical agricultural productivity globally by the end of the century. In this case, the benefits of mitigation typically extend well into temperate regions, but vary by crop and underlying climate model projections. Should large benefits to crop yields from carbon dioxide fertilization be realized, the effects of mitigation become much more mixed, though still positive globally and beneficial in many food insecure countries.

Mueller, Christoph↗

APH Experiments: Germination and Seedling Establishment Methods

Plant experiments during ground studies were conducted in the Advanced Plant Habitat (APH) Science Carrier (SC) for ensuring high germination rates and vigorous seedling establishment. The methods constitute a mixture of environmental and planting factors that control moisture and humidity during early seedling establishment. The APH uses granular media that is fertilized with slow release fertilizer pellets. Seeds were sanitized and their germination was tested prior to use in the SC. Seeds were glued in place with guar gum in different wicking materials. It was found that seedlings establishment was reduced if the chamber was too dry or if salt buildup near the seeds was permitted. Thus, germination was carried in media that was flooded and drained, in a chamber held at 80% relative humidity at a low wind speed of 0.3 m/s. After a week the humidity was lowered to 60% RH and wind speed was increased to 0.6 m/s. The germination of different plant species were found to respond differently to germination wicks or to gauze, as well as fertilization rates. Several methods for growing Arabidopsis, wheat, radish and peppers in the APH SC will be presented

O Monje↗

PLANNING FOR VEG-05 TOMATO CROP PRODUCTION ON THE INTERNATIONAL SPACE STATION

Growing fresh, nutritious, palatable produce for crew consumption during spaceflight may provide health-promoting, bioavailable nutrients and enhance the astronaut dietary experience as we move toward longer-duration missions. Tending plants may also serve as a countermeasure for crew psychological stresses associated with spaceflight. However, requirements to support consistent growth of a variety of nutritious crops under spaceflight environmental conditions remain unclear. This study explores the potential to grow crops for consumption on the International Space Station (ISS) using the Veggie vegetable-production system. Mizuna mustard was grown during VEG-04 studies in 2019, and human and plant data from those tests continue to be analyzed. Tomato plants will be grown for the VEG-05 experiment, and preflight definition studies are underway to ascertain the best hardware and operations for growing this fruiting crop. The variety of tomato selected for this study is ‘Red Robin’, a compact cherry tomato. Plants will be grown under two different red: blue lighting treatments using the Veggie units on ISS, and the impact of spectral quality on plant growth and yield, nutrient content, organoleptic acceptability, and microbial composition of the tomatoes will be assessed. Preliminary testing with this crop helped to identify responses to different analog types of growth hardware including both plant pillows and Passive Orbital Nutrient Delivery System (PONDS) units, and current testing is focusing on flight-like versions of this hardware. Challenges with fertilizer salts leaching out into the plant wicks and burning the stems of tomato were observed in earlier tests, so amended fertilizer and wick configurations have been developed. Crew procedures including plant thinning, watering, height adjustment with respect to lighting, and pollination are being validated. VEG-05 will be the first test of tomato fruit production on ISS. Lessons learned during preparation and implementation of the VEG-04 mizuna test for watering, and a separate ISS investigation with peppers (PH-04) in the Advanced Plant Habitat (APH) in terms of fertilizer, plant wicks, and pollination, will be adapted for this experiment. This research was co-funded by the Human Research Program and Space Biology (MTL#1075) in the ILSRA 2015 NRA call.

Veggie↗

Planning for VEG-05 Tomato Crop Production on the International Space Station

Growing fresh, nutritious, palatable produce for crew consumption during spaceflight may provide health-promoting, bioavailable nutrients and enhance the astronaut dietary experience as we move toward longer-duration missions. Tending plants may also serve as a countermeasure for crew psychological stresses associated with spaceflight. However, requirements to support consistent growth of a variety of nutritious crops under spaceflight environmental conditions remain unclear. This study explores the potential to grow crops for consumption on the International Space Station (ISS) using the Veggie vegetable-production system. Mizuna mustard was grown during VEG-04 studies in 2019, and human and plant data from those tests continue to be analyzed. Tomato plants will be grown for the VEG-05 experiment, and preflight definition studies are underway to ascertain the best hardware and operations for growing this fruiting crop. The variety of tomato selected for this study is ‘Red Robin’, a compact cherry tomato. Plants will be grown under two different red: blue lighting treatments using the Veggie units on ISS, and the impact of spectral quality on plant growth and yield, nutrient content, organoleptic acceptability, and microbial composition of the tomatoes will be assessed. Preliminary testing with this crop helped to identify responses to different analog types of growth hardware including both plant pillows and Passive Orbital Nutrient Delivery System (PONDS) units, and current testing is focusing on flight-like versions of this hardware. Challenges with fertilizer salts leaching out into the plant wicks and burning the stems of tomato were observed in earlier tests, so amended fertilizer and wick configurations have been developed. Crew procedures including plant thinning, watering, height adjustment with respect to lighting, and pollination are being validated. VEG-05 will be the first test of tomato fruit production on ISS. Lessons learned during preparation and implementation of the VEG-04 mizuna test for watering, and a separate ISS investigation with peppers (PH-04) in the Advanced Plant Habitat (APH) in terms of fertilizer, plant wicks, and pollination, will be adapted for this experiment. This research was co-funded by the Human Research Program and Space Biology (MTL#1075) in the ILSRA 2015 NRA call. Note: Presentation is a video formatted mp4 with a run time of 3 mins. 24 secs.

Veggie↗

Aboveground and Belowground Responses to Cyanobacterial Biofertilizer Supplement in a Semi-Arid, Perennial Bioenergy Cropping System

The need for sustainable agricultural practices to meet the food, feed, and fuel demands of a growing global population while reducing detrimental environmental impacts has driven research in multi-faceted approaches to agricultural sustainability. Perennial cropping systems and microbial biofertilizer supplements are two emerging strategies to increase agricultural sustainability that are studied in tandem for the first time in this study. During the establishment phase of a perennial switchgrass stand in SW Montana, USA, we supplemented synthetic fertilization with a nitrogen-fixing cyanobacterial biofertilizer (CBF) and were able to maintain aboveground crop productivity in comparison to a synthetic only (urea) fertilizer treatment. Soil chemical analysis conducted at the end of the growing season revealed that late-season nitrogen availability in CBF-supplemented field plots increased relative to urea-only plots. High-throughput sequencing of bacterial/archaeal and fungal communities suggested fine-scale responses of the microbial community and sensitivity to fertilization among arbuscular mycorrhizal fungi, Planctomycetes, Proteobacteria, and Actinobacteria. Given their critical role in plant productivity and soil nutrient cycling, soil microbiome monitoring is vital to understand the impacts of implementation of alternative agricultural practices on soil health.

biofertilizer↗

Verification Testing and Veg-05 Tomato Crop Production on the International Space Station

Production of fresh, nutritious, and tasty produce for astronauts during spaceflight may provide health-promoting, bioavailable nutrients and enhance the dietary experience as we move into longer-duration missions. Growing and caring for plants may also reduce the psychological stresses associated with spaceflight and enhance connections to Earth. Requirements to consistently grow a diversity of crops under spaceflight environmental conditions remain poorly defined. The VEG-05 experiment is part of a series of experiments with pick-and-eat salad crops to better define best practices for crop production and handling in space. VEG-05 and predecessor experiments VEG-04A and VEG-04B, use the Veggie vegetable production facilities on the International Space Station to grow salad crops under different spectral compositions. In VEG-04A and B, mizuna mustard was cultivated with two different red: blue light treatments, and in VEG-05 we are cultivating ‘Red Robin’ dwarf cherry tomatoes under the same light spectra. Light can impact the growth habit, yield, nutritional composition, microbial levels, and even flavor attributes within crops, and our team will assess these characteristics for this crop during VEG-05. Prior to launch and installation on ISS in late 2022, both a science verification test (SVT), and an experiment verification test (EVT) were conducted at Kennedy Space Center in ISS Environment Simulator Chambers. Science verification testing, and a previous fertilizer test, grew plants in both plant pillows and PONDS (Passive Orbital Nutrient Delivery System) units and tested two different fertilizer treatments in both sets of hardware, with each test under only one of the light conditions. Because of challenges validating the PONDS hardware on ISS, and with good crop production in plant pillows, the EVT moved forward using only plant pillows with the highest fertilizer composition tested during SVT, and two Veggie units were utilized. One Veggie had light settings consisting of equal levels of red: blue light (150 µmol/m2/s for each color) plus green light (30 µmol/m2/s) while the second Veggie had a 90:10 ratio of red: blue light (270 µmol/m2/s red and 30 µmol/m2/s blue) plus green, so each unit provided 330 µmol/m2/s of photosynthetically active radiation to the tomato crops on average. Our original plan, based on prior ground testing, was to grow the crop for 104 days and harvest at 80, 90 and 104 days after initiation. For SVT, under the equal red: blue light treatment, fruit ripening in plant pillows was delayed and fruit were not ripe by day 80, so actual harvest days were days 90, 97, and 104. For EVT we saw fruit ripening earlier, especially in the high red treatment, and so we harvested at days 83, 90, and 99 days after initiation. In SVT we had mostly daily watering, and this led to excess water in plant pillows, which leaked out. This excess water also caused fungus to grow on one leaf and a couple of plant stems. To reduce this excess moisture, we throttled back the watering for EVT, and used the root mat reservoir more frequently. This led to watering only every other day, reducing crew time needed for plant care, however, two wilting events occurred during this EVT, at days 51 and 75. Plants recovered from these wilting events, but these events may have influenced the rate of fruit ripening and flower formation. Regardless, more than 10 fruit were produced from each plant on average, with the high red treatment producing slightly heavier fruit. Microbial testing from fruit during SVT indicated that fruit were safe for consumption with microbial levels below detection limits. VEG-05 flight and ground operations are expected to run between December 2022 and March 2023. This research was co-funded by the Human Research Program and Space Biology (MTL#1075) in the ILSRA 2015 NRA call.

Gioia D. Massa↗

Verification Testing and Veg-05 Tomato Crop Production on the International Space Station

VEG-05 is an experiment to better define best practices for crop production and handling in space. Light can impact the growth habit, yield, nutritional composition, microbial levels, and flavor within crops and VEG-05 used the Veggie facilities on the International Space Station to grow ‘Red Robin’ dwarf tomatoes under different spectral compositions to assess these characteristics. Prior to launch, both a science verification test (SVT), and an experiment verification test (EVT) were conducted. SVT, and a previous fertilizer test, grew plants in both plant pillows and PONDS units and tested different fertilizer treatments, with each test under one of the light conditions. EVT used only plant pillows with the highest fertilizer composition tested, and two Veggie units were utilized. One Veggie had light settings consisting of equal levels of red: blue light while the second Veggie had a 90:10 ratio of red: blue light, both with the addition of ~10% green. For SVT, under the equal red: blue light treatment, fruit ripening in plant pillows was delayed. For EVT we saw fruit ripening earlier, especially in the red-rich treatment. In SVT we had mostly daily watering, and this led to excess water in plant pillows which leaked and caused fungus to grow. We reduced this excess in EVT, however, wilting events occurred. Regardless, more than 10 fruit were produced from each plant on average, with the high red treatment producing slightly heavier fruit. Microbial testing from fruit indicated that fruit were safe for consumption. VEG-05 flight operations ran December 2022 and March 2023, with considerable challenges in watering and unexpectedly low humidity on ISS during critical periods. Only 12 ripe fruit formed, and all were returned. Fruit and other samples are currently being analyzed. This research was co-funded by NASA’s Human Research Program and Space Biology.

Gioia Donna Massa↗

Verification Testing and VEG-05 Tomato Crop Production on the International Space Station

VEG-05 is an experiment to better define best practices for crop production and handling in space. Light can impact the growth habit, yield, nutritional composition, microbial levels, and flavor within crops and VEG-05 used the Veggie facilities on the International Space Station to grow ‘Red Robin’ dwarf tomatoes under different spectral compositions to assess these characteristics. Prior to launch, both a science verification test (SVT), and an experiment verification test (EVT) were conducted. SVT, and a previous fertilizer test, grew plants in both plant pillows and PONDS units and tested different fertilizer treatments, with each test under one of the light conditions. EVT used only plant pillows with the highest fertilizer composition tested, and two Veggie units were utilized. One Veggie had light settings consisting of equal levels of red: blue light while the second Veggie had a 90:10 ratio of red: blue light, both with the addition of ~10% green. For SVT, under the equal red: blue light treatment, fruit ripening in plant pillows was delayed. For EVT we saw fruit ripening earlier, especially in the red-rich treatment. In SVT we had mostly daily watering, and this led to excess water in plant pillows which leaked and caused fungus to grow. We reduced this excess in EVT, however, wilting events occurred. Regardless, more than 10 fruit were produced from each plant on average, with the high red treatment producing slightly heavier fruit. Microbial testing from fruit indicated that fruit were safe for consumption. VEG-05 flight operations ran December 2022 and March 2023, with considerable challenges in watering and unexpectedly low humidity on ISS during critical periods. Only 12 ripe fruit formed, and all were returned. Fruit and other samples are currently being analyzed. This research was co-funded by NASA’s Human Research Program and Space Biology.

Gioia D. Massa↗

Switchgrass cropping systems affect soil carbon and nitrogen and microbial diversity and activity on marginal lands

Abstract Switchgrass ( Panicum virgatum L.), as a dedicated bioenergy crop, can provide cellulosic feedstock for biofuel production while improving or maintaining soil quality. However, comprehensive evaluations of how switchgrass cultivation and nitrogen (N) management impact soil and plant parameters remain incomplete. We conducted field trials in three years (2016–2018) at six locations in the North Central Great Lakes Region to evaluate the effects of cropping systems (switchgrass, restored prairie, undisturbed control) and N rates (0, 56 kg N ha −1 year −1 ) on biomass yield and soil physicochemical, microbial, and enzymatic parameters. Switchgrass cropping system yielded an aboveground biomass 2.9–3.3 times higher than the other two systems (Jayawardena et al., unpublished data) but our study found that this biomass accumulation did not reduce soil dissolved organic C, total dissolved N (TDN), or bacterial diversity. The annual aboveground biomass removal for bioenergy feedstock, however, reduced soil microbial biomass C (MBC) and microbial biomass N (MBN) and bacterial richness in the second and third years; despite this, continuous monocropping of switchgrass improved soil TDN, inorganic N, bacterial diversity, and shoot biomass in the second and/or third years compared with the first year. N fertilization increased aboveground biomass yield by 1.2 times and significantly increased soil TDN, MBN, and the shoot biomass of switchgrass compared with the unfertilized control. Locations with higher C and N contents and lower C:N ratio had higher aboveground biomass, MBC, MBN, and the activity of BG, CBH, and UREA enzymes; by contrast, locations with higher pH had higher soil TDN and activity of NAG and LAP enzymes. Our research demonstrates that switchgrass cultivation could improve or maintain soil N content and N fertilization can increase plant biomass yield. The comprehensive data also can inform future biogeochemical models to successfully implement switchgrass for bioenergy production.

09 BIOMASS FUELS↗

Inter-Annual Precipitation Variability Decreases Switchgrass Productivity from Arid to Mesic Environments

Cellulosic biofuels are an important source of renewable biomass within the alternative energy portfolio. Switchgrass (Panicum virgatum L.), a perennial C 4 grass native to North America, is widely studied as a biofuel feedstock for its consistently high yields and minimal input requirements. The influences of precipitation amount and temporal variability on the fertilizer response of switchgrass productivity are not fully understood. Moreover, global climate models predict changes in rainfall patterns towards lower and increasingly variable soil water availability in several productive areas worldwide, which may impact net primary production of biofuel crops. We conducted a meta-analysis of aboveground net primary production of switchgrass from 48 publications encompassing 82 different locations, 11 soil types, 52 switchgrass cultivars, fertilizer inputs between 0 to 896 kg N ha –1 year –1 , and 1 to 6 years of annual productivity measures repeated on the same stand. Productivity of the lowland ecotype doubled with N rates > 131 kg N ha –1 year –1 , but upland ecotype productivity increased only by 50%. Results showed an optimum N rate of 30 to 60 kg N ha –1 year –1 for both ecotypes, after which biomass gain per unit of N added decreased. Growing season precipitation (GSPPT) and inter-annual precipitation variability (inter-PPTvar) affected both ecotypes similarly. Long-term mean annual precipitation (MAP) differentially affected lowland and upland productivity, depending on the N level. Productivity responses to MAP and GSPPT were similar for both upland and lowland ecotypes at none or low N rates. When N increased beyond 60 kg N ha –1 year –1 , lowland cultivars had a greater growth response to MAP than uplands. Productivity increased with increasing GSPPT and MAP and had a positive linear response to MAP ranging from 600 to 1200 mm year –1 . One third of the variability in switchgrass production was accounted for by inter-PPTvar. After accounting for MAP, sites with higher inter-PPTvar had lower switchgrass productivity than sites with lower inter-PPTvar. Increased inter-annual variation in precipitation reduced production of both ecotypes. As a result, predicted changes in the amount and timing of precipitation thus likely will exert greater influence on production of upland than lowland ecotypes of switchgrass.

54 ENVIRONMENTAL SCIENCES↗

Isotopic discrimination of natural and anthropogenic perchlorate sources in groundwater in a semi-arid region of northeastern Oregon (USA)

Perchlorate (ClO 4 - ) has synthetic and natural sources. Synthetic ClO 4 - is released to the environment from its use as an oxidant in military and aerospace applications, and from its presence in a variety of common commercial products, such as safety flares, chlorate herbicides, and fireworks. Natural sources of ClO 4 - in the environment include imported nitrate fertilizers derived from salt deposits in the Atacama Desert of Chile and indigenous natural ClO 4 - that accumulates in unsaturated soils and groundwaters in other arid and semi-arid environments, largely from atmospheric deposition. The stable isotope ratios of chlorine ( 37 Cl/ 35 Cl) and oxygen ( 18 O/ 16 O, 17 O/ 16 O) and the isotopic abundance of radioactive 36 Cl in ClO 4 - can be used to discriminate these different sources. Perchlorate was previously detected at relatively high concentrations (3.8–34.7 μg/L) in groundwater from many wells in the Boardman-Umatilla area near the Columbia River in northeastern Oregon, which is a semi-arid, highly agricultural, heavily irrigated area that includes several past and current military installations. Eight representative groundwater wells were sampled throughout this region and isotopic characteristics of ClO 4 - collected from each well were measured along with other chemical and isotopic parameters including tritium and other groundwater age indicators. We report isotopic data indicate that indigenous natural ClO 4 - was present in groundwater from all sampled wells and was the predominant source in five of the wells. Synthetic ClO 4 - was present in the three remaining wells with natural ClO 4 - , and a minor fraction of Atacama-fertilizer-derived ClO4- was indicated in one of the wells. Data from this study expand the geographic area of the USA in which indigenous natural ClO 4 - has been detected to include the semi-arid northwest. This study also illustrates the role of irrigation recharge as a mechanism for producing relatively high concentrations of indigenous natural ClO 4 - in groundwater by flushing accumulated salts from the unsaturated zone.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

pH-dependent Ca+2 oscillations prevent untimely acrosome reaction in human sperm

Highlights: • The external pH maintained during capacitation influences Acrosome Reaction. • Ca{sup 2+} oscillations prevent AR and are more frequent at external pH 6.5. • Pharmacological inhibition of Ca{sup 2+} oscillations restored Acrosome Reaction. During transit through the female reproductive tract, sperm encounter metabolites and environmental conditions that modulate various processes leading to fertilization. Intracellular Ca{sup 2+} dynamics regulate the acrosome reaction (AR), which involves exocytosis of the acrosomal granule, a prerequisite for successful fertilization. We explored the ability of progesterone, prostanglandin-E1, and GABA to induce Ca{sup 2+} mobilization and AR in single human spermatozoa capacitated under external pH (pH{sub e}) conditions found in different regions of the female reproductive tract (pH{sub e} 6.5, 7.4 and 8.0). The highest percentage of AR induction, regardless of the inducer, occurred when sperm were capacitated at pH{sub e} 7.4. Interestingly, at pH{sub e} 6.5 a high percentage of cells exhibit Ca{sup 2+} oscillations, which prevent AR. These oscillations involve extracellular and intracellular Ca{sup 2+} channels. Pharmacological inhibition of Ca{sup 2+} oscillations restores the ability of spermatozoa to undergo the AR when exposed to progesterone, even if capacitated at pH{sub e} 6.5.

60 APPLIED LIFE SCIENCES↗

Effects of mobile phone exposure on metabolomics in the male and female reproductive systems

Highlights: • Long-term exposure to EMF decreases sperm motility and fertilization. • Effects of EMF emitted from mobile phones are related to protein synthesis. • Oxidative stress based EMF exposure modulates nitric oxide level in the germ cells. • Oxidative stress based EMF exposure inhibits antioxidant mechanisms in the germ cells. With current advances in technology, a number of epidemiological and experimental studies have reported a broad range of adverse effects of electromagnetic fields (EMF) on human health. Multiple cellular mechanisms have been proposed as direct causes or contributors to these biological effects. EMF-induced alterations in cellular levels can activate voltage-gated calcium channels and lead to the formation of free radicals, protein misfolding and DNA damage. Because rapidly dividing germ cells go through meiosis and mitosis, they are more sensitive to EMF in contrast to other slower-growing cell types. In this review, possible mechanistic pathways of the effects of EMF exposure on fertilization, oogenesis and spermatogenesis are discussed. In addition, the present review also evaluates metabolomic effects of GSM-modulated EMFs on the male and female reproductive systems in recent human and animal studies. In this context, experimental and epidemiological studies which examine the impact of mobile phone radiation on the processes of oogenesis and spermatogenesis are examined in line with current approaches.

54 ENVIRONMENTAL SCIENCES↗

Soil contamination and sources of phthalates and its health risk in China: A review

Highlights: • PAE levels in soils of China were generally higher than the other countries. • DBP and DEHP are the dominant compounds in soil with obvious spatial distribution. • Urbanization and industrialization, application of plastic film and fertilizer are the major sources of PAEs in soil. • Uptake of PAEs by crops and human exposure to PAEs are reviewed. Phthalates (PAEs) are extensively used as plasticizers and constitute one of the most frequently detected organic contaminants in the environment. With the deterioration of eco-environment in China during the past three decades, many studies on PAE occurrence in soils and their risk assessments have been conducted which allow us to carry out a fairly comprehensive assessment of soil PAE contamination on a nation-wide scale. This review combines the updated information available associated with PAE current levels, distribution patterns (including urban soil, rural or agricultural soil, seasonal and vertical variations), potential sources, and human health exposure. The levels of PAEs in soils of China are generally at the high end of the global range, and higher than the grade II limits of the Environmental Quality Standard for soil in China. The most abundant compounds, di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP), display obvious spatial distribution in different provinces. It is noted that urbanization and industrialization, application of plastic film (especially plastic film mulching in agricultural soil) and fertilizer are the major sources of PAEs in soil. Uptake of PAEs by crops, and human exposure to PAEs via ingestion of soil and vegetables are reviewed, with scientific gaps highlighted.

54 ENVIRONMENTAL SCIENCES↗

Aloe arborescens juice prevents EMF-induced oxidative stress and thus protects from pathophysiology in the male reproductive system in vitro

Highlights: • Electromagnetic field (EMF) induces toxic events in spermatogenic cells. • Aloe juice prevents EMF-induced increased formation of reactive oxygen species. • Aloe juice inhibits ROS-mediated DNA damage, cell cycle arrest and apoptosis. • Aloe juice may preserves fertility from EMF-induced toxic events in mouse germ cells. More and more studies suggest that prolonged exposure to EMF may cause adverse biological effects and point directly to a significantly negative correlation between EMF and human health, especially men fertility. In our previous study, we reported that this could be related to the EMF-induced reactive oxygen species formation, followed by DNA damage, cell cycle arrest and apoptosis induction. In this study, we decided to expand our research by the search for substances which would prevent EMF-induced damage in spermatogenic cells. Such an agent seems to be Aloe arborescens Mill. juice, which was shown to possess a wide range of protective properties. The administration of aloe extract helps among others to prevent the formation of free radicals by various biochemical pathways. Therefore, the main aim of our study was to provide a significant knowledge concerning the mechanism involved in the multi-pathway cytoprotective response of aloe juice against EMF. The study was carried out in an in vitro mouse spermatogenesis pathway cell lines (GC-1 spg and GC-2 spd). Our results suggest that the aloe juice has many positive effects, especially for the cellular antioxidant systems by reducing the intracellular reactive oxygen species pool induced by EMF. In consequence, aloe juice prevents DNA damage, cell cycle arrest and therefore the viability and metabolic activity of both cell line tested are preserved. In conclusion, our study provides new insight into the underlying mechanisms through which aloe juice prevents spermatogenic cells from cytotoxic and genotoxic events.

54 ENVIRONMENTAL SCIENCES↗

Air gasification of biogas-derived digestate in a downdraft fixed bed gasifier

Highlights: • Air gasification of digestate with high ash content was studied in detail. • Compared to original biomass, less tar was observed in digestate gasification process. • Improved molar ratio of H{sub 2}/CO potential for chemical synthesis was gained at 800 °C. • The by-products (biochar and ash) can be land applied as fertilizer. - Abstract: Digestate is a byproduct from biomass anaerobic digestion process. Gasification of dried digestate to produce gasesous product might be a promising route. In this work, air gasification of digestate with high ash content was performed in a downdraft fixed bed gasifier at temperature varying from 600 °C to 800 °C and air equivalence ratio (ER) ranging from 0.25 to 0.30. The ash melting properties were firstly detected by the Intelligent Ash Melting Point Test, and the by-products (biochar and ash) were analyzed. The results showed that no ash slagging was observed and therefore it is feasible to operate digestate gasification under 800 °C and ER ranging from 0.25 to 0.30. High temperature favored gas production, 800 °C is proposed for digestate gasification in the present study. ER with a medium value improved gas quality and cold gas efficiency (CGE), and the optimal LHV of 4.78 MJ/N m{sup 3} and CGE of 67.01% were obtained with ER of 0.28. High ER favored the increase of gas yield and decrease of tar concentration, and the optimal gas yield of 2.15 N m{sup 3}/kg and tar concentration of 1.61 g/N m{sup 3} were achieved with ER of 0.30. Improved molar ratio of H{sub 2}/CO varying from 1.03 to 1.08 was obtained at 800 °C, indicating gaseous product has the potential for chemical synthesis processes (1 < H{sub 2}/CO < 2). The byproducts biochar and ash could be applied on land as fertilizer.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗