MARSBOx: Fungal and Bacterial Endurance From a Balloon-Flown Analog Mission in the Stratosphere

Whether terrestrial life can withstand the martian environment is of paramount interest for planetary protection measures and space exploration. To understand microbial survival potential in Mars-like conditions, several fungal and bacterial samples were launched in September 2019 on a large NASA scientific balloon flight to the middle stratosphere (∼38 km altitude) where radiation levels resembled values at the equatorial Mars surface. Fungal spores of Aspergillus niger and bacterial cells of Salinisphaera shabanensis, Staphylococcus capitis subsp. capitis, and Buttiauxella sp. MASE-IM-9 were launched inside the MARSBOx (Microbes in Atmosphere for Radiation, Survival, and Biological Outcomes Experiment) payload filled with an artificial martian atmosphere and pressure throughout the mission profile. The dried microorganisms were either exposed to full UV-VIS radiation (UV dose = 1148 kJ m−2) or were shielded from radiation. After the 5-h stratospheric exposure, samples were assayed for survival and metabolic changes. Spores from the fungus A. niger and cells from the Gram-(–) bacterium S. shabanensis were the most resistant with a 2- and 4-log reduction, respectively. Exposed Buttiauxella sp. MASE-IM-9 was completely inactivated (both with and without UV exposure) and S. capitis subsp. capitis only survived the UV shielded experimental condition (3-log reduction). Our results underscore a wide variation in survival phenotypes of spacecraft associated microorganisms and support the hypothesis that pigmented fungi may be resistant to the martian surface if inadvertently delivered by spacecraft missions.

Download Full-text

Persistence of Biomarker ATP and ATP-Generating Capability in Bacterial Cells and Spores Contaminating Spacecraft Materials under Earth Conditions and in a Simulated Martian Environment

Applied and Environmental Microbiology ◽

10.1128/aem.00891-08 ◽

2008 ◽

Vol 74 (16) ◽

pp. 5159-5167 ◽

Cited By ~ 16

Author(s):

Patricia Fajardo-Cavazos ◽

Andrew C. Schuerger ◽

Wayne L. Nicholson

Keyword(s):

Bacillus Pumilus ◽

Surface Radiation ◽

Dominant Factor ◽

Bacterial Cells ◽

Gas Composition ◽

Martian Surface ◽

Full Spectrum ◽

Planetary Protection ◽

Surface Conditions ◽

Uv C

ABSTRACTMost planetary protection research has concentrated on characterizing viable bioloads on spacecraft surfaces, developing techniques for bioload reduction prior to launch, and studying the effects of simulated martian environments on microbial survival. Little research has examined the persistence of biogenic signature molecules on spacecraft materials under simulated martian surface conditions. This study examined how endogenous adenosine-5′-triphosphate (ATP) would persist on aluminum coupons under simulated martian conditions of 7.1 mbar, full-spectrum simulated martian radiation calibrated to 4 W m−2of UV-C (200 to 280 nm), −10°C, and a Mars gas mix of CO2(95.54%), N2(2.7%), Ar (1.6%), O2(0.13%), and H2O (0.03%). Cell or spore viabilities ofAcinetobacter radioresistens, Bacillus pumilus, andB. subtiliswere measured in minutes to hours, while high levels of endogenous ATP were recovered after exposures of up to 21 days. The dominant factor responsible for temporal reductions in viability and loss of ATP was the simulated Mars surface radiation; low pressure, low temperature, and the Mars gas composition exhibited only slight effects. The normal burst of endogenous ATP detected during spore germination inB. pumilusandB. subtiliswas reduced by 1 or 2 orders of magnitude following, respectively, 8- or 30-min exposures to simulated martian conditions. The results support the conclusion that endogenous ATP will persist for time periods that are likely to extend beyond the nominal lengths of most surface missions on Mars, and planetary protection protocols prior to launch may require additional rigor to further reduce the presence and abundance of biosignature molecules on spacecraft surfaces.

Download Full-text

Using flow cytometry and light-induced fluorescence technique to characterizethe variability and characteristics of bioaerosols in springtime at Metro Atlanta, Georgia

10.5194/acp-2018-1073 ◽

2018 ◽

Author(s):

Arnaldo Negron ◽

Natasha DeLeon-Rodriguez ◽

Samantha M. Waters ◽

Luke D. Ziemba ◽

Bruce Anderson ◽

...

Keyword(s):

Flow Cytometry ◽

Nucleic Acid ◽

Acid Content ◽

Fungal Spores ◽

Epifluorescence Microscopy ◽

Nucleic Acid Content ◽

Rain Event ◽

Bacterial Cells ◽

Sampling System ◽

Spores And Pollen

Abstract. The abundance and speciation of primary biological aerosol particles (PBAP) is important for understanding their impacts on human health, cloud formation and ecosystems. Towards this, we have developed a protocol for quantifying PBAP collected from large volumes of air with a portable wet-walled cyclone bioaerosol sampler. A flow cytometry (FCM) protocol was then developed to quantify and characterize the PBAP populations from the sampler, which were confirmed against epifluorescence microscopy. The sampling system and FCM analysis were used to study PBAP in Atlanta, GA over a two-month period and showed clearly defined populations of DNA-containing particles: Low Nucleic Acid-content particles (bioLNA), High Nucleic Acid-content particles (HNA) being fungal spores and pollen. We find that daily-average springtime PBAP concentration (1 to 5 μm diameter) ranged between 1.4 × 104 and 1.1 × 105 m−3. The BioLNA population dominated PBAP during dry days (72 ± 18 %); HNA dominated the PBAP during humid days and following rain events, where HNA (e.g., wet-ejected fungal spores) comprised up to 92 % of the PBAP number. Concurrent measurements with a Wideband Integrated Bioaerosol Sensor (WIBS-4A) showed that FBAP and total FCM counts are similar; HNA (from FCM) significantly correlated with ABC type FBAP concentrations throughout the sampling period (and for the same particle size range, 1–5 μm diameter). However, the FCM bioLNA population, possibly containing bacterial cells, did not correlate to any FBAP type. The lack of correlation of any WIBS FBAP type with the bioLNA suggest bacterial cells may be more difficult to detect with autofluorescence than previously thought. Ιdentification of bacterial cells even in the FCM (bioLNA population) is challenging, given that the fluorescence level of stained cells at times may be comparable to that seen from abiotic particles. HNA and ABC displayed highest concentration on a humid and warm day after a rain event (4/14), suggesting that both populations correspond to wet-ejected fungal spores. Overall, information from both instruments combined reveals a highly dynamic airborne bioaerosol community over Atlanta, with a considerable presence of fungal spores during humid days, and a bioLNA population dominating bioaerosol community during dry days.

Download Full-text

Fluorescent biological aerosol particle concentrations and size distributions measured with an Ultraviolet Aerodynamic Particle Sizer (UV-APS) in Central Europe

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-3215-2010 ◽

2010 ◽

Vol 10 (7) ◽

pp. 3215-3233 ◽

Cited By ~ 159

Author(s):

J. A. Huffman ◽

B. Treutlein ◽

U. Pöschl

Keyword(s):

Particle Number ◽

Fungal Spores ◽

Number Concentration ◽

Size Distributions ◽

Bacterial Cells ◽

Spores And Pollen ◽

Measurement Results ◽

The Mean ◽

Particle Sizer ◽

Biological Aerosol Particles

Abstract. Primary Biological Aerosol Particles (PBAPs), including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany we used an Ultraviolet Aerodynamic Particle Sizer (UV-APS) to measure Fluorescent Biological Aerosol Particles (FBAPs), which provide an estimate of viable bioaerosol particles and can be regarded as an approximate lower limit for the actual abundance of PBAPs. Fluorescence of non-biological aerosol components are likely to influence the measurement results obtained for fine particles (<1 μm), but not for coarse particles (1–20 μm). Averaged over the four-month measurement period (August–December 2006), the mean number concentration of coarse FBAPs was ~3×10−2 cm−3, corresponding to ~4% of total coarse particle number. The mean mass concentration of FBAPs was ~1μg m−3, corresponding to ~20% of total coarse particle mass. The FBAP number size distributions exhibited alternating patterns with peaks at various diameters. A pronounced peak at ~3 μm was essentially always observed and can be described by the following campaign-average lognormal fit parameters: geometric mean diameter 3.2 μm, geometric standard deviation 1.3, number concentration 1.6×10−2 cm−3. This peak is likely due to fungal spores or agglomerated bacteria, and it exhibited a pronounced diel cycle (24-h) with maximum intensity during early/mid-morning. FBAP peaks around ~1.5 μm, ~5 μm, and ~13 μm were also observed, but less pronounced and less frequent. These may be single bacterial cells, larger fungal spores, and pollen grains, respectively. The observed number concentrations and characteristic sizes of FBAPs are consistent with microscopic, biological and chemical analyses of PBAPs in aerosol filter samples. To our knowledge, however, this is the first exploratory study reporting continuous online measurements of bioaerosol particles over several months and a range of characteristic size distribution patterns with a persistent bioaerosol peak at ~3 μm. The measurement results confirm that PBAPs account for a substantial proportion of coarse aerosol particle number and mass in continental boundary layer air. Moreover, they suggest that the number concentration of viable bioparticles is dominated by fungal spores or agglomerated bacteria with aerodynamic diameters around 3 μm rather than single bacterial cells with diameters around 1 μm.

Download Full-text

Off Earth Identification of Bacterial Populations Using 16S rDNA Nanopore Sequencing

Genes ◽

10.3390/genes11010076 ◽

2020 ◽

Vol 11 (1) ◽

pp. 76 ◽

Cited By ~ 4

Author(s):

Aaron S. Burton ◽

Sarah E. Stahl ◽

Kristen K. John ◽

Miten Jain ◽

Sissel Juul ◽

...

Keyword(s):

High Performance ◽

Space Station ◽

Bacterial Cells ◽

Sequencing Data ◽

Mock Community ◽

Bacterial Populations ◽

Microbial Identification ◽

Staphylococcus Capitis ◽

Staphylococcus Hominis ◽

Community Standard

The MinION sequencer has made in situ sequencing feasible in remote locations. Following our initial demonstration of its high performance off planet with Earth-prepared samples, we developed and tested an end-to-end, sample-to-sequencer process that could be conducted entirely aboard the International Space Station (ISS). Initial experiments demonstrated the process with a microbial mock community standard. The DNA was successfully amplified, primers were degraded, and libraries prepared and sequenced. The median percent identities for both datasets were 84%, as assessed from alignment of the mock community. The ability to correctly identify the organisms in the mock community standard was comparable for the sequencing data obtained in flight and on the ground. To validate the process on microbes collected from and cultured aboard the ISS, bacterial cells were selected from a NASA Environmental Health Systems Surface Sample Kit contact slide. The locations of bacterial colonies chosen for identification were labeled, and a small number of cells were directly added as input into the sequencing workflow. Prepared DNA was sequenced, and the data were downlinked to Earth. Return of the contact slide to the ground allowed for standard laboratory processing for bacterial identification. The identifications obtained aboard the ISS, Staphylococcus hominis and Staphylococcus capitis, matched those determined on the ground down to the species level. This marks the first ever identification of microbes entirely off Earth, and this validated process could be used for in-flight microbial identification, diagnosis of infectious disease in a crewmember, and as a research platform for investigators around the world.

Download Full-text

In vitro anti-oxidant and cytotoxic analysis of Pogostemon mollis Benth

Bangladesh Journal of Pharmacology ◽

10.3329/bjp.v11i1.24157 ◽

2016 ◽

Vol 11 (1) ◽

pp. 148 ◽

Cited By ~ 10

Author(s):

Elizabeth George ◽

Muniyandi Kasipandi ◽

Mudili Vekataramana ◽

Kalagatur Naveen Kumar ◽

Joseph Anthuvan Allen ◽

...

Keyword(s):

Antioxidant Activity ◽

Ethyl Acetate ◽

Ethyl Acetate Extract ◽

Fungal Spores ◽

Bacterial Cells ◽

Free Radical Damage ◽

Cytotoxic Effects ◽

Anti Oxidant ◽

Radical Damage

In the present study, the anti-oxidant and cytotoxic effects of the different solvent extracts of Pogostemon mollis were analysed. The phenolic, tannin and flavonoid contents were highest in the ethyl acetate extract and analogous to the antioxidant activity results. The extracts showed activities similar to the standard antioxidants. The extent to which the extracts protect free radical damage on DNA was evaluated and showed good genoprotective effects. Bacterial cells and fungal spores and hyphae showed visible damages due to the treatment of ethyl acetate extract. Finally in the cytotoxic analysis, IC50 value was calculated based on the absorbance value of different concentrations. It concluded that P. mollis is a prospective candidate for the various therapeutic applications especially its ethyl acetate extract.

Download Full-text

Inactivation of recalcitrant protozoan oocysts and bacterial endospores in drinking water using high-intensity pulsed UV light irradiation

Water Science & Technology Water Supply ◽

10.2166/ws.2012.017 ◽

2012 ◽

Vol 12 (4) ◽

pp. 513-522 ◽

Cited By ~ 6

Author(s):

J. C. Hayes ◽

M. Garvey ◽

A. M. Fogarty ◽

E. Clifford ◽

N. J. Rowan

Keyword(s):

High Intensity ◽

Uv Light ◽

Waste Water Treatment ◽

Scale Up ◽

Clear Trend ◽

E Coli ◽

Log Reduction ◽

Bacterial Endospores ◽

Pulsed Uv Light ◽

Uv Dose

This constitutes the first study to compare the use of high-intensity pulsed UV light (PUV) irradiation for the novel destruction of harmful protozoan (Cryptosporidium parvum Iowa isolate) oocysts and bacterial (Clostridium perfringens ATCC 13124 and Bacillus cereus ATCC 11178) endospores in artificially-spiked water where these organisms are resistant to conventional chlorination. Experimental results revealed that all three test organisms in their dormant recalcitrant state required extended levels of pulsing to achieve significant reductions in numbers compared to other similarly PUV-treated Escherichia coli ATCC 25922 that is a non-spore forming indicator of faecal pollution in water. 120 pulses at 900 V or 16.2 J per pulse (equivalent to a UV dose of 8.39 μJ cm−2) were required to achieve ca. 2 log C. perfringens spore numbers, whereas a similar level of PUV irradiation reduced both C. parvum oocysts and B. cereus endospores by ca. 5 log orders. A comparative ca. 5 log reduction of E. coli cell numbers was achieved after only 25 pulses at 900 V (equivalent to a UV dose of 1.74 μJ cm−2). A clear trend emerged where the order of resistance to PUV-irradiation observed was C. perfringens endospores > C. parvum oocysts, B. cereus endospores > E. coli cells. This study suggests disinfection kinetic data for the more resistant C. perfringens endospores can be used as a measure of estimating disinfection efficacy of PUV treatments for C. parvum oocysts in water, avoiding the need to use complex animal or cell culture infectivity models that are only available in specialised laboratories with highly trained technicians. This study will inform future studies exploring scale-up of PUV at waste-water treatment plants.

Download Full-text

Antimicrobial Effects of Silver Nanoparticles against Bacterial Cells Adhered to Stainless Steel Surfaces

Journal of Food Protection ◽

10.4315/0362-028x.jfp-11-276 ◽

2012 ◽

Vol 75 (4) ◽

pp. 701-705 ◽

Cited By ~ 26

Author(s):

EMILIANE A. ARAÚJO ◽

NÉLIO J. ANDRADE ◽

LUIS HENRIQUE M. da SILVA ◽

PATRÍCIA C. BERNARDES ◽

ÁLVARO V. N. de C. TEIXEIRA ◽

...

Keyword(s):

Silver Nanoparticles ◽

Stainless Steel ◽

Food Industry ◽

Antimicrobial Activities ◽

New Method ◽

Resistant Bacteria ◽

Bacterial Cells ◽

Antimicrobial Effects ◽

Log Reduction ◽

Steel Surfaces

Given the increasing number of antibiotic-resistant bacteria and the need to synthesize new antimicrobials, silver has attracted interest in the scientific community because of its recognized antimicrobial activity. This study aimed to evaluate the antimicrobial effects of silver nanoparticles (NP) obtained by a new method and tested at concentrations of 6 μg/ml and 60 μg/ml against the species Staphylococcus aureus, Listeria innocua, Salmonella Choleraesuis, Pseudomonas aeruginosa, Escherichia coli, and Bacillus cereus. The ability of these nanoparticles to remove or kill vegetative cells adhered to stainless steel surfaces was also evaluated. We observed that the NP obtained with the new method, concentrated silver nanoparticles (CNP), and silver nanoparticles with added sodium chloride (NPNaCl) had high antimicrobial activities (P < 0.05). We also verified that the most effective condition for the removal of P. aeruginosa cells on stainless steel coupons (10 by 10 mm) was immersion of the surfaces in CNP. The CNP treatment produced a 5-log reduction of the microbial population after 30 to 60 min of immersion. The CNP treatment also performed better than water and sodium carbonate, a compound commonly applied in clean-in-place procedures in the food industry, in removing adherent B. cereus cells from stainless steel cylinders. Therefore, these results suggest that NP synthesized by a new procedure may be used as antimicrobials in the food industry, for example, for the sanitization of utensils that come into contact with foods.

Download Full-text

A new water-soluble bactericidal agent for the treatment of polymicrobial infections

10.20944/preprints202008.0106.v1 ◽

2020 ◽

Author(s):

Alessandro Presentato ◽

Elena Piacenza ◽

Antonino Scurria ◽

Lorenzo Albanese ◽

Federica Zabini ◽

...

Keyword(s):

Water Soluble ◽

Hydrodynamic Cavitation ◽

Minimal Bactericidal Concentration ◽

Bacterial Cells ◽

Citrus Pectin ◽

Gram Negative ◽

Log Reduction ◽

Citrus Flavonoids ◽

Polymicrobial Infections ◽

Bactericidal Agent

Grapefruit and lemon pectin obtained from the respective waste citrus peels via hydrodynamic cavitation in water only are powerful, broad-scope antimicrobial alternatives to antibiotics against Gram-negative and -positive pathogens. Dubbed IntegroPectin, these pectic polymers functionalized with citrus flavonoids and terpenes show superior antimicrobial activity when compared to commercial citrus pectin. Similarly to commercial pectin, lemon IntegroPectin determined ca. 3 log reduction of Staphylococcus aureus cells, while an enhanced activity of commercial citrus pectin was detected in the case of Pseudomonas aeruginosa cells with a minimal bactericidal concentration (MBC) of 15 mg mL-1. Although grapefruit and lemon IntegroPectin share equal MBC in the case of P. aeruginosa cells, grapefruit IntegroPectin shows boosted activity upon exposure of S. aureus cells with a 40 mg mL-1 biopolymer concentration being sufficient to achieve complete killing of the bacterial cells. Insight on the mechanism of action of these biocompatible antimicrobials and their effect on bacterial cells, at the morphological level, were obtained indirectly through Fourier Transform Infrared spectroscopy and directly through scanning electron microscopy. In the era of antimicrobial resistance, these results are of great societal and sanitary relevance as they open new avenues to develop innovative antimicrobials for the treatment of polymicrobial infections unlikely to develop drug resistance.

Download Full-text

Using flow cytometry and light-induced fluorescence to characterize the variability and characteristics of bioaerosols in springtime in Metro Atlanta, Georgia

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-1817-2020 ◽

2020 ◽

Vol 20 (3) ◽

pp. 1817-1838 ◽

Cited By ~ 1

Author(s):

Arnaldo Negron ◽

Natasha DeLeon-Rodriguez ◽

Samantha M. Waters ◽

Luke D. Ziemba ◽

Bruce Anderson ◽

...

Keyword(s):

Flow Cytometry ◽

Nucleic Acid ◽

Acid Content ◽

Aerosol Particles ◽

Fungal Spores ◽

Epifluorescence Microscopy ◽

Nucleic Acid Content ◽

Rain Event ◽

Bacterial Cells ◽

Biological Aerosol Particles

Abstract. The abundance and speciation of primary biological aerosol particles (PBAP) is important for understanding their impacts on human health, cloud formation, and ecosystems. Towards this, we have developed a protocol for quantifying PBAP collected from large volumes of air with a portable wet-walled cyclone bioaerosol sampler. A flow cytometry (FCM) protocol was then developed to quantify and characterize the PBAP populations from the sampler, which were confirmed against epifluorescence microscopy. The sampling system and FCM analysis were used to study PBAP in Atlanta, GA, over a 2-month period and showed clearly defined populations of nucleic-acid-containing particles: low nucleic acid-content particles above threshold (LNA-AT) and high nucleic acid-content particles (HNA) likely containing wet-ejected fungal spores and pollen. We find that the daily-average springtime PBAP concentration (1 to 5 µm diameter) ranged between 1.4×104 and 1.1×105 m−3. The LNA-AT population dominated PBAP during dry days (72±18 %); HNA dominated the PBAP during humid days and following rain events, where HNA comprised up to 92 % of the PBAP number. Concurrent measurements with a Wideband Integrated Bioaerosol Sensor (WIBS-4A) showed that fluorescent biological aerosol particles (FBAP) and total FCM counts are similar; HNA (from FCM) moderately correlated with ABC-type FBAP concentrations throughout the sampling period (and for the same particle size range, 1–5 µm diameter). However, the FCM LNA-AT population, possibly containing bacterial cells, did not correlate with any FBAP type. The lack of correlation of any WIBS FBAP type with the LNA-AT suggests that airborne bacterial cells may be more difficult to unambiguously detect with autofluorescence than currently thought. Identification of bacterial cells even in the FCM (LNA-AT population) is challenging, given that the fluorescence level of stained cells at times may be comparable to that seen from abiotic particles. HNA and ABC displayed the highest concentration on a humid and warm day after a rain event (14 April 2015), suggesting that both populations correspond to wet-ejected fungal spores. Overall, information from both instruments combined reveals a highly dynamic airborne bioaerosol community over Atlanta, with a considerable presence of fungal spores during humid days and an LNA-AT population dominating the bioaerosol community during dry days.

Download Full-text

Seasonal and diurnal variations in Martian surface ultraviolet irradiation: biological and chemical implications for the Martian regolith

International Journal of Astrobiology ◽

10.1017/s1473550402001180 ◽

2003 ◽

Vol 2 (1) ◽

pp. 21-34 ◽

Cited By ~ 38

Author(s):

M. R. Patel ◽

A. Bérces ◽

C. Kolb ◽

H. Lammer ◽

P. Rettberg ◽

...

Keyword(s):

Oxidation Potential ◽

Diurnal Variations ◽

Martian Surface ◽

Dose Rates ◽

Uv Irradiance ◽

Seasonal And Diurnal Variations ◽

Phage T7 ◽

Biological Interpretation ◽

Uv Dose ◽

Martian Regolith

The issue of the variation of the surface ultraviolet (UV) environment on Mars was investigated with particular emphasis being placed on the interpretation of data in a biological context. A UV model has been developed to yield the surface UV irradiance at any time and place over the Martian year. Seasonal and diurnal variations were calculated and dose rates evaluated. Biological interpretation of UV doses is performed through the calculation of DNA damage effects upon phage T7 and Uracil, used as examples for biological dosimeters. A solar UV ‘hotspot’ was revealed towards perihelion in the southern hemisphere, with a significant damaging effect upon these species. Diurnal profiles of UV irradiance are also seen to vary markedly between aphelion and perihelion. The effect of UV dose is also discussed in terms of the chemical environment of the Martian regolith, since UV irradiance can reach high enough levels so as to have a significant effect upon the soil chemistry. We show, by assuming that H2O is the main source of hydrogen in the Martian atmosphere, that the stoichiometrically desirable ratio of 2:1 for atmospheric H and O loss rates to space are not maintained and at present the ratio is about 20:1. A large planetary oxygen surface sink is therefore necessary, in contrast with escape to space. This surface oxygen sink has important implications for the oxidation potential and the toxicology of the Martian soil. UV-induced adsorption of {\rm O}_{2}^{-} super-radicals plays an important role in the oxidative environment of the Martian surface, and the biologically damaging areas found in this study are also shown to be regions of high subsurface oxidation. Furthermore, we briefly cover the astrobiological implications for landing sites that are planned for future Mars missions.

Download Full-text