J. Wise, Hong Xie, J. Wise, Michael Mason, A. Jeevarajan, W. Wallace, J. Wise
ABSTRACT The National Aeronautics and Space Administration (NASA) has plans to further their manned space exploration to Mars and possibly beyond. The potential toxicity of lunar and Martian dusts to astronauts is a big concern. Primary routes of exposure for astronauts are dermal contact, ocular contact, and inhalation. In this study, we focused on dermal contact exposure using human skin cells to investigate the cytotoxic and genotoxic effects of two fractions of lunar dust simulant (JSC-1A-vf, JSC-1A-f) and a Mars dust simulant (Mars-1A), and compared them to urban dust (urban particulate matter), as urban dust toxicity is better understood and thus, provides a good comparison. Our data show the three simulants and urban dust are cytotoxic to human skin cells. The JSC-1A-vf lunar dust simulant is more cytotoxic than the JSC-1A-f and urban dust. Urban dust cytotoxicity is similar to Mars dust simulant after 120 h exposure. All three dust simulants and urban dust show similar low genotoxicity effects. Our data suggest extraterrestrial dust can damage skin cells and may have the potential to be harmful to humans.
{"title":"Comparative Toxicity of Lunar, Martian Dust Simulants, and Urban Dust in Human Skin Fibroblast Cells","authors":"J. Wise, Hong Xie, J. Wise, Michael Mason, A. Jeevarajan, W. Wallace, J. Wise","doi":"10.2478/gsr-2015-0005","DOIUrl":"https://doi.org/10.2478/gsr-2015-0005","url":null,"abstract":"ABSTRACT The National Aeronautics and Space Administration (NASA) has plans to further their manned space exploration to Mars and possibly beyond. The potential toxicity of lunar and Martian dusts to astronauts is a big concern. Primary routes of exposure for astronauts are dermal contact, ocular contact, and inhalation. In this study, we focused on dermal contact exposure using human skin cells to investigate the cytotoxic and genotoxic effects of two fractions of lunar dust simulant (JSC-1A-vf, JSC-1A-f) and a Mars dust simulant (Mars-1A), and compared them to urban dust (urban particulate matter), as urban dust toxicity is better understood and thus, provides a good comparison. Our data show the three simulants and urban dust are cytotoxic to human skin cells. The JSC-1A-vf lunar dust simulant is more cytotoxic than the JSC-1A-f and urban dust. Urban dust cytotoxicity is similar to Mars dust simulant after 120 h exposure. All three dust simulants and urban dust show similar low genotoxicity effects. Our data suggest extraterrestrial dust can damage skin cells and may have the potential to be harmful to humans.","PeriodicalId":90510,"journal":{"name":"Gravitational and space research : publication of the American Society for Gravitational and Space Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90547842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David J. Smith, Prital J. Thakrar, Anthony E. Bharrat, A. Dokos, T. Kinney, Leandro M. James, M. Lane, Christina L. M. Khodadad, F. Maguire, P. R. Maloney, Nicole L. Dawkins
Abstract The survival and transit of microorganisms in Earth's upper atmosphere is relevant to terrestrial ecology and astrobiology, but the topic is understudied due to a scarcity of suitable flight systems. We designed, built, and flew a self-contained payload, Exposing Microorganisms in the Stratosphere (E-MIST), on a large scientific balloon launched from New Mexico on 24 August 2014. The payload carried Bacillus pumilus SAFR-032, a highly-resilient spore-forming bacterial strain originally isolated from a NASA spacecraft assembly facility. Our test flight evaluated E-MIST functionality in the stratosphere, including microbiological procedures and overall instrument performance. Herein, we summarize features of the E-MIST payload, protocols, and preliminary results that indicate it is possible to conduct a tightly-controlled microbiological experiment in the stratosphere while collecting pertinent environmental data. Additional studies of this nature may permit survival models for microbes traveling through Earth's harsh upper atmosphere. Moreover, measuring the endurance of spacecraft-associated microbes at extreme altitudes may help predict their response on the surface of Mars.
{"title":"A Balloon-Based Payload for Exposing Microorganisms in the Stratosphere (E-MIST)","authors":"David J. Smith, Prital J. Thakrar, Anthony E. Bharrat, A. Dokos, T. Kinney, Leandro M. James, M. Lane, Christina L. M. Khodadad, F. Maguire, P. R. Maloney, Nicole L. Dawkins","doi":"10.2478/gsr-2014-0019","DOIUrl":"https://doi.org/10.2478/gsr-2014-0019","url":null,"abstract":"Abstract The survival and transit of microorganisms in Earth's upper atmosphere is relevant to terrestrial ecology and astrobiology, but the topic is understudied due to a scarcity of suitable flight systems. We designed, built, and flew a self-contained payload, Exposing Microorganisms in the Stratosphere (E-MIST), on a large scientific balloon launched from New Mexico on 24 August 2014. The payload carried Bacillus pumilus SAFR-032, a highly-resilient spore-forming bacterial strain originally isolated from a NASA spacecraft assembly facility. Our test flight evaluated E-MIST functionality in the stratosphere, including microbiological procedures and overall instrument performance. Herein, we summarize features of the E-MIST payload, protocols, and preliminary results that indicate it is possible to conduct a tightly-controlled microbiological experiment in the stratosphere while collecting pertinent environmental data. Additional studies of this nature may permit survival models for microbes traveling through Earth's harsh upper atmosphere. Moreover, measuring the endurance of spacecraft-associated microbes at extreme altitudes may help predict their response on the surface of Mars.","PeriodicalId":90510,"journal":{"name":"Gravitational and space research : publication of the American Society for Gravitational and Space Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77340634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Egusquiza, Robert Benjamin Runyon, Jordan Ringel, Craig Wayne Cole Seber, Gonzalo Leyva, Jose Correa, Coulibaly Datoliban Roland, Mujahid Umar, Ming Xiao, J. Bushoven, J. J. Goto
Abstract An experimental chamber and hand-manipulated syringe apparatus were designed, tested, and utilized to assess calcium oxalate crystal yield in Terrestrial-g (1 g), micro-g (0.01 g), Lunar-g (0.16 g), and Martian-g (0.38 g). Aqueous solutions of calcium chloride (100 mM) and oxalic acid (200 mM) were mixed to precipitate calcium oxalate crystals. Gravitational differences were hypothesized to result in differences in the yield of crystal formation. These data are essential for efforts to better understand the correlation between calcium oxalate crystal formation and the production of kidney stones often associated with long-term space missions. The analyses of crystal formation produced in the micro-g (≅0.01 g) conditions of this study suggest that calcium oxalate monohydrate formation yield is slightly greater than those produced in Terrestrial-g conditions.
{"title":"Calcium Oxalate Crystal Yield in Various Gravity Environments","authors":"R. Egusquiza, Robert Benjamin Runyon, Jordan Ringel, Craig Wayne Cole Seber, Gonzalo Leyva, Jose Correa, Coulibaly Datoliban Roland, Mujahid Umar, Ming Xiao, J. Bushoven, J. J. Goto","doi":"10.2478/gsr-2014-0013","DOIUrl":"https://doi.org/10.2478/gsr-2014-0013","url":null,"abstract":"Abstract An experimental chamber and hand-manipulated syringe apparatus were designed, tested, and utilized to assess calcium oxalate crystal yield in Terrestrial-g (1 g), micro-g (0.01 g), Lunar-g (0.16 g), and Martian-g (0.38 g). Aqueous solutions of calcium chloride (100 mM) and oxalic acid (200 mM) were mixed to precipitate calcium oxalate crystals. Gravitational differences were hypothesized to result in differences in the yield of crystal formation. These data are essential for efforts to better understand the correlation between calcium oxalate crystal formation and the production of kidney stones often associated with long-term space missions. The analyses of crystal formation produced in the micro-g (≅0.01 g) conditions of this study suggest that calcium oxalate monohydrate formation yield is slightly greater than those produced in Terrestrial-g conditions.","PeriodicalId":90510,"journal":{"name":"Gravitational and space research : publication of the American Society for Gravitational and Space Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75264484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The objectives of this study were to evaluate transdermal scopolamine for motion sickness prophylaxis, and to evaluate off-vertical axis rotation (OVAR) as a laboratory model of motion sickness. This was a randomized, prospective, double-blind study design, set in a vestibular research laboratory. The experimental subjects consisted of 12 patients – 7 male, 5 female – ages 21 to 57, with normal auditory/vestibular function. The intervention was off-vertical axis rotation 20 degrees in the dark after administration of transdermal scopolamine or placebo. The main outcome measures were time duration of tolerated off-vertical rotation, and subjective symptom reporting during rotation at one-minute intervals on a 0–4 scale. Results were as follows: patients treated with transdermal scopolamine had statistically significant improved tolerance time to off-vertical axis rotation. Reported symptom-atology on the 0–4 subjective symptom scale was significantly improved, as compared to placebo, and was dose-dependent. Conclusions are as follows: off-vertical axis rotation is a useful modality for the evaluation of motion sickness medications. Transdermal scopolamine showed statistically significant dose-dependent effects in mitigating OVAR-induced motion sickness symptomatology and was well tolerated.
{"title":"Off-Vertical Axis Rotational Assessment of Transdermal Scopolamine for Motion Sickness Prophylaxis","authors":"D. Woodard, G. Knox, S. Wood, Cathy P. DiBiase","doi":"10.2478/gsr-2014-0014","DOIUrl":"https://doi.org/10.2478/gsr-2014-0014","url":null,"abstract":"Abstract The objectives of this study were to evaluate transdermal scopolamine for motion sickness prophylaxis, and to evaluate off-vertical axis rotation (OVAR) as a laboratory model of motion sickness. This was a randomized, prospective, double-blind study design, set in a vestibular research laboratory. The experimental subjects consisted of 12 patients – 7 male, 5 female – ages 21 to 57, with normal auditory/vestibular function. The intervention was off-vertical axis rotation 20 degrees in the dark after administration of transdermal scopolamine or placebo. The main outcome measures were time duration of tolerated off-vertical rotation, and subjective symptom reporting during rotation at one-minute intervals on a 0–4 scale. Results were as follows: patients treated with transdermal scopolamine had statistically significant improved tolerance time to off-vertical axis rotation. Reported symptom-atology on the 0–4 subjective symptom scale was significantly improved, as compared to placebo, and was dose-dependent. Conclusions are as follows: off-vertical axis rotation is a useful modality for the evaluation of motion sickness medications. Transdermal scopolamine showed statistically significant dose-dependent effects in mitigating OVAR-induced motion sickness symptomatology and was well tolerated.","PeriodicalId":90510,"journal":{"name":"Gravitational and space research : publication of the American Society for Gravitational and Space Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90787672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
U. Reidt, A. Helwig, L. Plobner, Veronika Lugmayr, Ulrich Treutlein, S. Kharin, Yu.I. Smirnov, N. Novikova, J. Lenic, V. Fetter, T. Hummel
ABSTRACT In this report, we describe the initial colonization of environmental microorganisms associated with ISS on four different materials (Nomex, cable labeling material, printed circuit board, and aluminum), which are commonly used at the ISS. Material substrates were placed in the Russian segment of the ISS in a Target Book for 135 days. After the incubation, the Target Book was analyzed on Earth by determining colony-forming units and identifying the microorganisms by rRNA gene sequencing. The highest cell concentrations and widest biological diversity were on the polymer materials, such as Nomex and cable labeling material. Additional molecular biological identification revealed the following organisms as typical pioneer microorganisms: Staphylococcus spp., Bacillus spp., Streptococcus spp., Cladosporium spp., Sphingomonas spp., Micrococcus luteus, and Stenotrophomonas maltophilia.
{"title":"Study of Initial Colonization by Environmental Microorganisms in the Russian Segment of the International Space Station (ISS)","authors":"U. Reidt, A. Helwig, L. Plobner, Veronika Lugmayr, Ulrich Treutlein, S. Kharin, Yu.I. Smirnov, N. Novikova, J. Lenic, V. Fetter, T. Hummel","doi":"10.2478/gsr-2014-0012","DOIUrl":"https://doi.org/10.2478/gsr-2014-0012","url":null,"abstract":"ABSTRACT In this report, we describe the initial colonization of environmental microorganisms associated with ISS on four different materials (Nomex, cable labeling material, printed circuit board, and aluminum), which are commonly used at the ISS. Material substrates were placed in the Russian segment of the ISS in a Target Book for 135 days. After the incubation, the Target Book was analyzed on Earth by determining colony-forming units and identifying the microorganisms by rRNA gene sequencing. The highest cell concentrations and widest biological diversity were on the polymer materials, such as Nomex and cable labeling material. Additional molecular biological identification revealed the following organisms as typical pioneer microorganisms: Staphylococcus spp., Bacillus spp., Streptococcus spp., Cladosporium spp., Sphingomonas spp., Micrococcus luteus, and Stenotrophomonas maltophilia.","PeriodicalId":90510,"journal":{"name":"Gravitational and space research : publication of the American Society for Gravitational and Space Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78657388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The advent of the new generation of suborbital space vehicles is opening up a new and exciting realm of space science that should be of great interest to biologists. These vehicles make it possible to explore biological responses and adaptations that occur in the first few minutes of entering spaceflight and also in the first few minutes after return from space. Historically these transition stages in spaceflight have simply not been available for research, especially within human-rated vehicles. Given that complex biological responses are seldom linear over time, and that essentially all current experiments on the International Space Station (ISS) are conducted after stabilization on orbit, biologists are missing the chance to understand the pathways that lead from terrestrial existence to successful spaceflight adaptation and back. Studies conducted on suborbital spacecraft can therefore be an innovative approach to filling a substantial gap in knowledge regarding the temporal dynamics of biological responses to successful spaceflight physiological adaptation.
{"title":"Suborbital Vehicles to Study Transition Adaptation to Spaceflight – Why Biologists Should Care About the New Suborbital Flight Opportunities","authors":"R. Ferl","doi":"10.2478/gsr-2014-0016","DOIUrl":"https://doi.org/10.2478/gsr-2014-0016","url":null,"abstract":"Abstract The advent of the new generation of suborbital space vehicles is opening up a new and exciting realm of space science that should be of great interest to biologists. These vehicles make it possible to explore biological responses and adaptations that occur in the first few minutes of entering spaceflight and also in the first few minutes after return from space. Historically these transition stages in spaceflight have simply not been available for research, especially within human-rated vehicles. Given that complex biological responses are seldom linear over time, and that essentially all current experiments on the International Space Station (ISS) are conducted after stabilization on orbit, biologists are missing the chance to understand the pathways that lead from terrestrial existence to successful spaceflight adaptation and back. Studies conducted on suborbital spacecraft can therefore be an innovative approach to filling a substantial gap in knowledge regarding the temporal dynamics of biological responses to successful spaceflight physiological adaptation.","PeriodicalId":90510,"journal":{"name":"Gravitational and space research : publication of the American Society for Gravitational and Space Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77310453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Natasha J. L. Sng, Jordan A. Callaham, R. Ferl, A. Paul
Abstract Biological experiments on-orbit that demonstrate the effects of gravity on plants require precise control of the initiation of plant development. Preserving seed dormancy is critical to experiments that endeavor to study the effects of the orbital environment, independent of contributions from either a normal gravity, or launch. However, spaceflight experiments are often tightly constrained with respect to the configuration of the biology and associated hardware, and it is rarely possible to launch dry seeds separated from their growth substrate. Described here are techniques established to maintain viable seeds that can remain dormant for up to a month at room temperature, and hydrated on the surface of solid, Phytagel growth medium. The configuration can also accommodate a brief (less than one minute) exposure to light during the quiescent period for quick inspection for any breaks in dormancy, and for contamination. The data presented outline the preparation of sealed, Phytagel media plates of dormant Arabidopsis thaliana seed that can be activated in situ when unwrapped and installed within a lighted growth habitat. These protocols were developed primarily for spaceflight scenarios where seeded plates must be prepared ahead of time and kept at ambient temperatures. However, these protocols can be adapted for any field application where it is desirable to transport dormant, seeded plates to a remote location where it would not be possible to prepare sterile culture plates.
{"title":"Arabidopsis thaliana for Spaceflight Applications–Preparing Dormant Biology for Passive Stowage and On-Orbit Activation","authors":"Natasha J. L. Sng, Jordan A. Callaham, R. Ferl, A. Paul","doi":"10.2478/gsr-2014-0018","DOIUrl":"https://doi.org/10.2478/gsr-2014-0018","url":null,"abstract":"Abstract Biological experiments on-orbit that demonstrate the effects of gravity on plants require precise control of the initiation of plant development. Preserving seed dormancy is critical to experiments that endeavor to study the effects of the orbital environment, independent of contributions from either a normal gravity, or launch. However, spaceflight experiments are often tightly constrained with respect to the configuration of the biology and associated hardware, and it is rarely possible to launch dry seeds separated from their growth substrate. Described here are techniques established to maintain viable seeds that can remain dormant for up to a month at room temperature, and hydrated on the surface of solid, Phytagel growth medium. The configuration can also accommodate a brief (less than one minute) exposure to light during the quiescent period for quick inspection for any breaks in dormancy, and for contamination. The data presented outline the preparation of sealed, Phytagel media plates of dormant Arabidopsis thaliana seed that can be activated in situ when unwrapped and installed within a lighted growth habitat. These protocols were developed primarily for spaceflight scenarios where seeded plates must be prepared ahead of time and kept at ambient temperatures. However, these protocols can be adapted for any field application where it is desirable to transport dormant, seeded plates to a remote location where it would not be possible to prepare sterile culture plates.","PeriodicalId":90510,"journal":{"name":"Gravitational and space research : publication of the American Society for Gravitational and Space Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86582346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The emerging commercial suborbital rocket industry in the U.S. presents new opportunities for research and education missions. Some companies have been publicized by the world's media and others are lower-profile. Additionally, some companies were created for the space tourism market and others have no current plans to fly humans at all. Most companies already have a Payload User's Guide published at their websites. The time for experimenters to take note of this industry is now, because in early 2014 a number of these companies were already operational or in flight test phase of their business development. When thousands of dollars, instead of millions for traditional NASA or European Space Agency (ESA) sounding rockets, are needed for a suborbital flight, many more researchers will be able to afford suborbital testing and research. In general, these rocket companies seek to provide at least three minutes of high-quality weightless test times from approximately 60 km to 100 km in altitude, and back to 60 km. Purdue University has been fortunate to have secured numerous launches for small payloads during these developmental and early operational years of the industry. Lessons from these launches include lessons in design, payload environment, procedures, launch site infrastructure, and travel preparations.
{"title":"An Experimenter's Experiences in Early Commercial Suborbital Flight","authors":"S. Collicott","doi":"10.2478/gsr-2014-0017","DOIUrl":"https://doi.org/10.2478/gsr-2014-0017","url":null,"abstract":"Abstract The emerging commercial suborbital rocket industry in the U.S. presents new opportunities for research and education missions. Some companies have been publicized by the world's media and others are lower-profile. Additionally, some companies were created for the space tourism market and others have no current plans to fly humans at all. Most companies already have a Payload User's Guide published at their websites. The time for experimenters to take note of this industry is now, because in early 2014 a number of these companies were already operational or in flight test phase of their business development. When thousands of dollars, instead of millions for traditional NASA or European Space Agency (ESA) sounding rockets, are needed for a suborbital flight, many more researchers will be able to afford suborbital testing and research. In general, these rocket companies seek to provide at least three minutes of high-quality weightless test times from approximately 60 km to 100 km in altitude, and back to 60 km. Purdue University has been fortunate to have secured numerous launches for small payloads during these developmental and early operational years of the industry. Lessons from these launches include lessons in design, payload environment, procedures, launch site infrastructure, and travel preparations.","PeriodicalId":90510,"journal":{"name":"Gravitational and space research : publication of the American Society for Gravitational and Space Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82694419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Bacteria of the genera Bacillus and Staphylococcus are frequent inhabitants of the International Space Station (ISS) and represent possible opportunistic pathogens. The effect of simulated microgravity on growth and the frequency of mutation to antibiotic resistance in the model surrogate organisms Bacillus subtilis (B. subtilis) and Staphylococcus epidermidis (S. epidermidis) were investigated. The test organisms were cultivated for six days in Rotating Wall Vessel (RWV) clinostats either in the vertical (simulated microgravity) or horizontal (1 g control) orientation. Parameters measured were: optical densities (ODs); viable counts; frequencies of resistance to rifampicin (RFM); and frequencies of double resistance to RFM and trimethoprim (TMP). The results indicated that the response to simulated microgravity differed in the two microorganisms. Both B. subtilis and S. epidermidis grew to higher ODs and cell numbers in simulated microgravity. However, the frequencies of mutation, both to RFM resistance and double resistance to RFM and TMP, were observed to increase significantly in simulated microgravity-grown B. subtilis but not in S. epidermidis.
{"title":"Differing Responses in Growth and Spontaneous Mutation to Antibiotic Resistance in Bacillus subtilis and Staphylococcus epidermidis Cells Exposed to Simulated Microgravity","authors":"P. Fajardo-Cavazos, Raed Narvel, W. Nicholson","doi":"10.2478/gsr-2014-0011","DOIUrl":"https://doi.org/10.2478/gsr-2014-0011","url":null,"abstract":"ABSTRACT Bacteria of the genera Bacillus and Staphylococcus are frequent inhabitants of the International Space Station (ISS) and represent possible opportunistic pathogens. The effect of simulated microgravity on growth and the frequency of mutation to antibiotic resistance in the model surrogate organisms Bacillus subtilis (B. subtilis) and Staphylococcus epidermidis (S. epidermidis) were investigated. The test organisms were cultivated for six days in Rotating Wall Vessel (RWV) clinostats either in the vertical (simulated microgravity) or horizontal (1 g control) orientation. Parameters measured were: optical densities (ODs); viable counts; frequencies of resistance to rifampicin (RFM); and frequencies of double resistance to RFM and trimethoprim (TMP). The results indicated that the response to simulated microgravity differed in the two microorganisms. Both B. subtilis and S. epidermidis grew to higher ODs and cell numbers in simulated microgravity. However, the frequencies of mutation, both to RFM resistance and double resistance to RFM and TMP, were observed to increase significantly in simulated microgravity-grown B. subtilis but not in S. epidermidis.","PeriodicalId":90510,"journal":{"name":"Gravitational and space research : publication of the American Society for Gravitational and Space Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82433321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martin W Hayes, G. Stutte, M. McKeon-Bennett, P. Murray
Abstract The endophytic fungus, Piriformospora indica, developed a subepidermal infection within Medicago truncatula at 1 g and at simulated microgravity over a period of 15 days, resulting in intracellular colonization of mature host tissue. At 1 g, P. indica inoculation affected the growth and morphology of M. truncatula, predominantly roots. Inoculated M. truncatula had a significantly greater number of roots (102%), total root length (88%), and dry root weight (25%) than non-inoculated plants. Effects on shoot morphology of P. indica inoculated M. truncatula included longer (31%) and heavier (30%) shoots, along with increased leaf surface area (98%). P. indica retained the ability to promote the growth of M. truncatula under simulated microgravity conditions upon two dimensional clinostatic rotation, significantly increasing root number by 51% and root length by 48%. These physiological and morphological changes may mitigate biotic and abiotic stresses that would otherwise limit crop productivity.
{"title":"Mutualism Within a Simulated Microgravity Environment - Piriformospora indica Promotes the Growth of Medicago truncatula","authors":"Martin W Hayes, G. Stutte, M. McKeon-Bennett, P. Murray","doi":"10.2478/gsr-2014-0015","DOIUrl":"https://doi.org/10.2478/gsr-2014-0015","url":null,"abstract":"Abstract The endophytic fungus, Piriformospora indica, developed a subepidermal infection within Medicago truncatula at 1 g and at simulated microgravity over a period of 15 days, resulting in intracellular colonization of mature host tissue. At 1 g, P. indica inoculation affected the growth and morphology of M. truncatula, predominantly roots. Inoculated M. truncatula had a significantly greater number of roots (102%), total root length (88%), and dry root weight (25%) than non-inoculated plants. Effects on shoot morphology of P. indica inoculated M. truncatula included longer (31%) and heavier (30%) shoots, along with increased leaf surface area (98%). P. indica retained the ability to promote the growth of M. truncatula under simulated microgravity conditions upon two dimensional clinostatic rotation, significantly increasing root number by 51% and root length by 48%. These physiological and morphological changes may mitigate biotic and abiotic stresses that would otherwise limit crop productivity.","PeriodicalId":90510,"journal":{"name":"Gravitational and space research : publication of the American Society for Gravitational and Space Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73223714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：