A5025912644- Planetary Science and Exploration
- Astro and Planetary Science
- Space Science and Extraterrestrial Life
- Spaceflight effects on biology
- Space Exploration and Technology
- Isotope Analysis in Ecology
- Microbial Community Ecology and Physiology
- Scientific Research and Discoveries
- Space exploration and regulation
- Plasma Applications and Diagnostics
- Biocrusts and Microbial Ecology
- Bacterial biofilms and quorum sensing
- Microbial bioremediation and biosurfactants
- Synthesis and Biological Evaluation
- Plasma Diagnostics and Applications
- Methane Hydrates and Related Phenomena
- Diatoms and Algae Research
- Toxin Mechanisms and Immunotoxins
- Mass Spectrometry Techniques and Applications
- Organic and Inorganic Chemical Reactions
- Monoclonal and Polyclonal Antibodies Research
- Protist diversity and phylogeny
- Medical Device Sterilization and Disinfection
- Aerosol Filtration and Electrostatic Precipitation
- Cryospheric studies and observations
California State Polytechnic University
2014-2024
Blue Marble Space
2019-2023
Blue Marble Space Institute of Science
2019-2021
Pomona College
2017
Ames Research Center
2002-2013
Florida Atlantic University
2003-2005
Argonne National Laboratory
2005
University of California, Santa Cruz
2000-2004
University of California, San Francisco
2004
Executive Office of the President
1997
The lower cloud layer of Venus (47.5-50.5 km) is an exceptional target for exploration due to the favorable conditions microbial life, including moderate temperatures and pressures (∼60°C 1 atm), presence micron-sized sulfuric acid aerosols. Nearly a century after ultraviolet (UV) contrasts Venus' were discovered with Earth-based photographs, substances mechanisms responsible changes in albedo are still unknown. While current models include sulfur dioxide iron chloride as UV absorbers,...
We present a re-examination of mass spectral data obtained from the Pioneer Venus Large Probe Neutral Mass Spectrometer. Our interpretations differing trace chemical species are suggestive redox disequilibria in Venus' middle clouds. Assignments to (at 51.3 km) include phosphine, hydrogen sulfide, nitrous acid, nitric carbon monoxide, hydrochloric cyanide, ethane, and potentially ammonia, chlorous several tentative PxOy species. All parent ions were predicated upon assignment corresponding...
Long-standing unexplained Venus atmosphere observations and chemical anomalies point to unknown chemistry but also leave room for the possibility of life. The include several gases out thermodynamic equilibrium (e.g., tens ppm O2, possible presence PH3 NH3, SO2 H2O vertical abundance profiles), an composition large, lower cloud particles, "unknown absorber(s)." Here we first review relevant properties venusian then describe atmospheric how they motivate future astrobiology missions Venus.
Self-assembling biomolecules that form highly ordered structures have attracted interest as potential alternatives to conventional lithographic processes for patterning materials. Here, we introduce a general technique nanoparticle arrays using two-dimensional crystals of genetically modified hollow protein called chaperonins. Constrained chemical synthesis transition metal nanoparticles is initiated templates functionalized with polyhistidine sequences. These are into because the...
We present a case for the exploration of Venus as an astrobiology target—(1) investigations focused on likelihood that liquid water existed surface in past, leading to potential origin and evolution life, (2) into habitable zones within Venus' present-day clouds Venus-like exo atmospheres, (3) theoretical how active aerobiology may impact radiative energy balance (4) application these investigative approaches toward better understanding atmospheric dynamics habitability exoplanets. The...
We show that solar irradiances calculated across Venus' clouds support the potential for Earth-like phototrophy and treatment of aerosols containing neutralized sulfuric acid favor a habitable zone. The phototrophic atmosphere was assessed by calculating (200-2000 nm, 15° zenith angle, local noon) using radiative transfer model accounted absorption scattering major minor atmospheric constituents. Comparisons to Earth's surface (46 W m-2, 280-400 nm) suggest middle lower receive ∼87% less...
In this work, we show that Venus’ aerosols possess a complex chemical composition and contain previously underestimated reservoirs of water iron sulfate. These assessments are based on re-analyses data acquired in atmosphere 1978 by the Pioneer Venus Large Probe (PVLP). Data from Neutral Mass Spectrometer (LNMS) Gas Chromatograph (LGC) consistent with evolved gas analysis. During descent through clouds, likely collected into intake inlet assemblies LNMS LGC. The then differentially...
An oxygen plasma sustained at 13.56 MHz in a standardized reactor with planar induction coil was used for biological decontamination experiments. Optical emission, mass spectrometry, Langmuir probe, and electrical measurements were applied to detection of chemical species ion-energy e ux analysis. These diagnostics identie ed plasma-mode transition the range 13 ‐67-Pa pressure 100 ‐330-W power coil. At higher lower power, dim mode (primarily by stray capacitive coupling). A primarily...
In this study, we expand upon the biogeography of biological soil crusts (BSCs) and provide molecular insights into microbial community biochemical dynamics along vertical BSC column structure, across a transect increasing surface coverage in central Mojave Desert, CA, United States. Next generation sequencing reveals bacterial profile that is distinct among BSCs southwestern Distribution major phyla topsoils included Cyanobacteria (33 ± 8%), Proteobacteria (26 6%), Chloroflexi (12 4%), with...
The search for life beyond Earth has focused on Mars and the icy moons Europa Enceladus, all of which are considered a safe haven due to evidence current or past water. surface Venus, other hand, extreme conditions that make it nonhabitable environment as we know it. This is in contrast, however, its cloud layer, which, while still an environment, may prove be some forms similar extremophiles Earth. We consider venusian clouds habitable based presence (1) solvent biochemical reactions, (2)...
The effects of cold plasma on Deinococcus radiodurans, plasmid DNA, and model proteins were assessed using microbiological, spectrometric, biochemical techniques. In low power O2 (∼25 W, ∼45 mTorr, 90 min), D. a radiation-resistant bacterium, showed 99.999% reduction in bioburden. higher (100 W 500 mTorr), the rate increased about 10-fold observation by atomic force microscopy significant damage to cell. Damage cellular lipids, proteins, chromosome was indicated losses infrared spectroscopic...
Abstract This paper highlights unique sites in Ladakh, India, investigated during our 2016 multidisciplinary pathfinding expedition to the region. We summarize scientific findings and site's potential support science exploration, testing of new technologies protocols within framework astrobiology research. Ladakh has several accessible, diverse, pristine extreme environments at very high altitudes (3000–5700 m above sea level). These include glacial passes, sand dunes, hot springs saline...
The possibility of an ocean within the icy shell Jupiter's moon Europa has established that world as a primary candidate in search for extraterrestrial life our Solar System. This paper evaluates potential to detect evidence microbial by comparing laboratory studies terrestrial microorganisms with measurements from Galileo Near Infrared Imaging Spectrometer (NIMS). If interior at one time harbored life, some may remain surface materials. Examination spectra extremophiles measured cryogenic...
Inhibition of lipoxygenase (LO) is currently an important goal biomedical research due to its critical role in asthma, atherosclerosis, and cancer regulation. Steady-state kinetic data indicate that oleic acid (OA) a simple competitive inhibitor for soybean lipoxygenase; however, isotope effect (KIE) suggest more complicated inhibitory mechanism. To investigate the effects fatty acids on thoroughly, we have synthesized novel lipoxygenase, (Z)-9-octadecenyl sulfate (oleyl sulfate, OS), which...
In this report, we expand upon the enzymology and ecology of soil catalases through development application a simple kinetic model field-amenable assay based volume displacement. Through approach, (A) directly relate apparent Michaelis-Menten terms to catalase reaction mechanism, (B) obtain upper estimates intrinsic rate constants for community (k3'), along with moles per 16S rRNA gene copy number, (C) utilize specific activities (SAs) biomass permafrost communities (LOD, ~104 number gdw−1),...
<p>The interest in the possibility of life on Venus is driven not just by curiosity about originating another Earth-like environment, but because that may be playing a critical role planet’s present, and possibly its past, atmospheric state. The brilliance night sky (as viewed from Earth) due to highly reflective cloud cover, 28 km thick at equator.  Its spectral albedo 90% wavelengths > 500 nm, it drops gradually 40% around 370 nm before...
As focus for exploration of Mars transitions from current robotic explorers to development crewed missions, it remains important protect the integrity scientific investigations at Mars, as well Earth's biosphere any potential harmful effects returned martian material. This is discipline planetary protection, and Committee on Space Research (COSPAR) maintains consensus international policy guidelines how this implemented. Based National Aeronautics Administration (NASA) European Agency (ESA)...
The microbiology of the spacecraft assembly process is paramount importance to planetary exploration, as biological contamination that can result from remote-enabled carries potential impact both life-detection experiments and extraterrestrial evolution. Accordingly, insights into mechanisms range extremotolerance Acinetobacter radioresistens 50v1, a Gram-negative bacterium isolated surface preflight Mars Odyssey orbiter, were gained by using combination microbiological, enzymatic, proteomic...
There is much debate whether the fatty acid substrate of lipoxygenase binds "carboxylate-end first" or "methyl-end in active site soybean lipoxygenase-1 (sLO-1). To address this issue, we investigated sLO-1 mutants Trp500Leu, Trp500Phe, Lys260Leu, and Arg707Leu with steady-state stopped-flow kinetics. Our data indicate that substrates (linoleic (LA), arachidonic (AA)), products (13-(S)-hydroperoxy-9,11-(Z,E)-octadecadienoic (HPOD) 15-(S)-hydroperoxyeicosatetraeonic (15-(S)-HPETE)) interact...
The microbiological inventory of spacecraft and the associated assembly facility surfaces represent primary pool forward contaminants that may impact integrity life-detection missions. Herein, we report on characterization several strains hydrogen peroxide-resistant Acinetobacter, which were isolated during Mars Phoenix lander assembly. All Phoenix-associated Acinetobacter possessed very high catalase specific activities, strain, A. gyllenbergii 2P01AA, displayed a survival against peroxide...
Spacecraft assembly facilities are oligotrophic and low-humidity environments, which routinely cleaned using alcohol wipes for benchtops spacecraft materials, alkaline detergents floors. Despite these cleaning protocols, possess a persistent, diverse, dynamic, low abundant core microbiome, where the Acinetobacter among dominant members of community. In this report, we show that several spacecraft-associated metabolize or biodegrade reagents ethanol (ethyl alcohol), 2-propanol (isopropyl...
Earth and Space Science Open Archive This preprint has been submitted to is under consideration at Geophysical Research Letters. ESSOAr a venue for early communication or feedback before peer review. Data may be preliminary.Learn more about preprints preprintOpen AccessYou are viewing an older version [v3]Go new versionVenus' Mass Spectra Show Signs of Disequilibria in the Middle CloudsAuthorsRakeshMoguliDSanjay S.LimayeiDMichaelWayiDJaimeCordovaiDSee all authors Rakesh MoguliDCorresponding...
We present a significantly updated CO2 altitude profile for Venus (64.2–0.9 km) and provide support potential deep lower atmospheric haze of particles (≤17 km). extracted this information by developing new analytical model mass spectra obtained the Pioneer Large Probe (PVLP) Neutral Mass Spectrometer (LNMS). Our accounts changes in LNMS configuration output during descent enables disentanglement isobaric species via data fitting routine that adjusts mass-dependent peak shape. The yields...