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At least 37 records · Page 2

Project environmental microbiology as related to planetary quarantine

Microbiological analyses of soil particles allow for the following conclusions: (1) there is a considerable range in the values of aerobic, mesophilic microbial counts associated with different size soil fractions; (2) as soil particle size increases, there is an increase in the mean microbial concentration per particle; (3) plate counts of aerobic, mesophilic organisms in unheated soils yielded a mean concentration of about six organisms per particle for the smallest soil fraction; (4) aerobic, mesophilic counts for sonicated particles heated at 80 C for 20 minutes yielded mean values of about two organisms per particle for the smallest particles; (5) some actinomycetes associated with the soil fractions could survive dry heat treatment at 110 C for one hour; and (6) soil particles stored under ambient laboratory conditions for 2.5 years aerobic, mesophilic plate counts which were comparable or slightly greater than the counts for more recently collected soil.

Pflug, I. J.↗

Project environmental microbiology as related to planetary quarantine

The viability and dry heat resistance of indigenous microflora associated with small soil particles were investigated. An aluminum boat TDT CUP-TSA solid media system was developed for the analyses; a complete description of the technique is included. Data cited here were obtained using analyses of individual soil particles. Detailed particle viability profiles for dry heat effects were determined for Kennedy Space Center soil. At 110 C at least some particles retained viability through a heating period of between 8 and 16 hours. Single particles heated at 125 C for 80 minutes or longer did not show evidence of viability under test conditions. Preliminary aerobic, mesophilic plate counts of the 74-88 micron m soil fraction yielded mean values of 16.2 organisms per dark particle and 2.6 organisms per light particle. Heat treatment of particles in a dry atmosphere did not appear to increase the rate of inactivation for in situ soil particle microflora.

Pflug, I. J.↗

Environmental microbiology as related to planetary quarantine

The mechanistic basis of the synergetic effect of combined heat and radiation on microbial destruction was analyzed and results show that radiation intensity, temperature, and relative humidity are the determining factors. Dry heat resistance evaluation for selected bacterial spore crops indicates that different strains of Bacillus stearothermophilus demonstrate marked differences in resistance. Preliminary work to determine the effects of storage time, suspending medium, storage temperature and spore crop cleaning procedures on dry heat survival characteristics of Bacillus subtilis var. Niger, and dry heat resistance of natural microflora in soil particles is also reported.

Pflug, I. J.↗

Environmental microbiology as related to planetary quarantine

Continued experimental work related to dry heat resistance of microorganisms. One phase of this research has been concerned with the viability and dry heat resistance of indigenous microflora associated with small soil particles. The second part of this report is an analysis of the present status of dry heat sterilization. An attempt is made to integrate results for both laboratory grown spores and spores in soil.

Pflug, I. J.↗

Biogeochemistry, Planetary Protection, and Astromaterials Curation: A Story of Environmental Microbiology at NASA

The astromaterials curation office at the NASA Johnson Space Center is responsible for curating and allocating all of the extraterrestrial samples collected by NASA. This includes lunar samples, meteorites, cometary material, asteroid samples and individual atoms of the solar wind. Some of these collections are susceptible to biological alteration by terrestrial microbes. I will describe the microbial monitoring of the clean rooms used to store these samples and the ecology we find therein. This research is helping NASA design better cleanrooms for even more sensitive samples like those currently being collected on Mars. I will also discuss our group’s research on improved identification methods, biological alteration of meteorites, and efforts to sample microbes on the outside of the International Space Station.

Aaron B. Regberg↗

Microbial contamination of spacecraft

Spacecraft and space habitats supporting human exploration contain a diverse population of microorganisms. Microorganisms may threaten human habitation in many ways that directly or indirectly impact the health, safety, or performance of astronauts. The ability to produce and maintain spacecraft and space stations with environments suitable for human habitation has been established over 40 years of human space flight. An extensive database of environmental microbiological parameters has been provided for short-term (< 20 days) space flight by more than 100 missions aboard the Space Shuttle. The NASA Mir Program provided similar data for long-duration missions. Interestingly, the major bacterial and fungal species found in the Space Shuttle are similar to those encountered in the nearly 15-year-old Mir. Lessons learned from both the US and Russian space programs have been incorporated into the habitability plan for the International Space Station. The focus is on preventive measures developed for spacecraft, cargo, and crews. On-orbit regular housekeeping practices complete with visual inspections are essential, along with microbiological monitoring. Risks associated with extended stays on the Moon or a Mars exploration mission will be much greater than previous experiences because of additional unknown variables. The current knowledge base is insufficient for exploration missions, and research is essential to understand the effects of space flight on biological functions and population dynamics of microorganisms in spacecraft. Equally important is a better understanding of the immune response and of human-microorganism-environment interactions during long-term space habitation.

Mir Project↗

Polyphasic taxonomy of the genus Shewanella and description of Shewanella oneidensis sp. nov

The genus Shewanella has been studied since 1931 with regard to a variety of topics of relevance to both applied and environmental microbiology. Recent years have seen the introduction of a large number of new Shewanella-like isolates, necessitating a coordinated review of the genus. In this work, the phylogenetic relationships among known shewanellae were examined using a battery of morphological, physiological, molecular and chemotaxonomic characterizations. This polyphasic taxonomy takes into account all available phenotypic and genotypic data and integrates them into a consensus classification. Based on information generated from this study and obtained from the literature, a scheme for the identification of Shewanella species has been compiled. Key phenotypic characteristics were sulfur reduction and halophilicity. Fatty acid and quinone profiling were used to impart an additional layer of information. Molecular characterizations employing small-subunit 16S rDNA sequences were at the limits of resolution for the differentiation of species in some cases. As a result, DNA-DNA hybridization and sequence analyses of a more rapidly evolving molecule (gyrB gene) were performed. Species-specific PCR probes were designed for the gyrB gene and used for the rapid screening of closely related strains. With this polyphasic approach, in addition to the ten described Shewanella species, two new species, Shewanella oneidensis and 'Shewanella pealeana', were recognized; Shewanella oneidensis sp. nov. is described here for the first time.

NASA Discipline Exobiology↗

Microbiological aspects of clean room technology as applied to surgery, with special reference to unidirectional airflow systems

The microbiological aspects of clean room technology as applied to surgery were reviewed. The following pertinent subject areas were examined: (1) clean room technology per se and its utilization for surgery, (2) microbiological monitoring of the clean room surgical environment, (3) clean rooms and their impact on operating room environmental microbiology, and (4) the effect of the technology on surgical wound infection rates. Conclusions were drawn for each topic investigated.

Wardle, M. D.↗

Shedding Light on Microbial Dark Matter with A Universal Language of Life

The majority of microbial genomes have yet to be cultured, and most proteins predicted from microbial genomes or sequenced from the environment cannot be functionally annotated. As a result, current computational approaches to describe microbial systems rely on incomplete reference databases that cannot adequately capture the full functional diversity of the microbial tree of life, limiting our ability to model high-level features of biological sequences. The scientific community needs a means to capture the functionally and evolutionarily relevant features underlying biology, independent of our incomplete reference databases. Such a model can form the basis for transfer learning tasks, enabling downstream applications in environmental microbiology, medicine, and bioengineering. Here we present LookingGlass, a deep learning model capturing a “universal language of life”. LookingGlass encodes contextually-aware, functionally and evolutionarily relevant representations of short DNA reads, distinguishing reads of disparate function, homology, and environmental origin. We demonstrate the ability of LookingGlass to be fine-tuned to perform a range of diverse tasks: to identify novel oxidoreductases, to predict enzyme optimal temperature, and to recognize the reading frames of DNA sequence fragments. LookingGlass is the first contextually-aware, general purpose pre-trained “biological language” representation model for short-read DNA sequences. LookingGlass enables functionally relevant representations of otherwise unknown and unannotated sequences, shedding light on the microbial dark matter that dominates life on Earth.

A Hoarfrost↗

Mass spectrometry

A review of mass spectrometry in organic chemistry is given, dealing with advances in instrumentation and computer techniques, selected topics in gas-phase ion chemistry, and applications in such fields as biomedicine, natural-product studies, and environmental pollution analysis. Innovative techniques and instrumentation are discussed, along with chromatographic-mass spectrometric on-line computer techniques, mass spectral interpretation and management techniques, and such topics in gas-phase ion chemistry as electron-impact ionization and decomposition, photoionization, field ionization and desorption, high-pressure mass spectrometry, ion cyclotron resonance, and isomerization reactions of organic ions. Applications of mass spectrometry are examined with respect to bio-oligomers and their constituents, biomedically important substances, microbiology, environmental organic analysis, and organic geochemistry.

Burlingame, A. L.↗

Microbiological Lessons Learned from the Space Shuttle

After 30 years of being the centerpiece of NASA s human spacecraft, the Space Shuttle will retire. This highly successful program provided many valuable lessons for the International Space Station (ISS) and future spacecraft. Major microbiological risks to crewmembers include food, water, air, surfaces, payloads, animals, other crewmembers, and ground support personnel. Adverse effects of microorganisms are varied and can jeopardize crew health and safety, spacecraft systems, and mission objectives. Engineering practices and operational procedures can minimize the negative effects of microorganisms. To minimize problems associated with microorganisms, appropriate steps must begin in the design phase of new spacecraft or space habitats. Spacecraft design must include requirements to control accumulation of water including humidity, leaks, and condensate on surfaces. Materials used in habitable volumes must not contribute to microbial growth. Use of appropriate materials and the implementation of robust housekeeping that utilizes periodic cleaning and disinfection will prevent high levels of microbial growth on surfaces. Air filtration can ensure low levels of bioaerosols and particulates in the breathing air. The use of physical and chemical steps to disinfect drinking water coupled with filtration can provide safe drinking water. Thorough preflight examination of flight crews, consumables, and the environment can greatly reduce pathogens in spacecraft. The advances in knowledge of living and working onboard the Space Shuttle formed the foundation for environmental microbiology requirements and operations for the International Space Station (ISS) and future spacecraft. Research conducted during the Space Shuttle Program resulted in an improved understanding of the effects of spaceflight on human physiology, microbial properties, and specifically the host-microbe interactions. Host-microbe interactions are substantially affected by spaceflight. Astronaut immune functions were found to be altered. Selected microorganisms were found to become more virulent during spaceflight. The increased knowledge gained on the Space Shuttle resulted in further studies of the host-microbe interactions on the ISS to determine if countermeasures were necessary. Lessons learned from the Space Shuttle Program were integrated into the ISS resulting in the safest space habitat to date.

Pierson, Duane L.↗

Mission requirements: Second Skylab mission SL-3

Complete SL-3 mission objectives and requirements, as revised 1 February 1972 (Rev. 6), are presented. Detailed test objectives are also given on the medical experiments, Apollo Telescope Mount experiments, Earth Resources Experiment Package, and corollary experiments and environmental microbiology experiments.

Source record↗

Probability of illness definition for the Skylab flight crew health stabilization program

Management and analysis of crew and environmental microbiological data from SMEAT and Skylab are discussed. Samples were collected from ten different body sites on each SMEAT and Skylab crew-member on approximately 50 occasions and since several different organisms could be isolated from each sample, several thousand lab reports were generated. These lab reports were coded and entered in a computer file and from the file various tabular summaries were constructed.

Source record↗

Johnson Space Center's Regenerative Life Support Systems Test Bed

The Regenerative Life Support Systems (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for human testing of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. The facility supports NASA's Advanced Life Support (ALS) Program. The facility is comprised of two large scale plant growth chambers, each with approximately 11 m2 growing area. The root zone in each chamber is configurable for hydroponic or solid media plant culture systems. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), is capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in a planetary surface habitat; the other chamber, the Ambient Pressure Growth Chamber (APGC) operates at ambient atmospheric pressure. The air lock of the VPGC is currently being outfitted for short duration (1 to 15 day) human habitation at ambient pressures. Testing with and without human subjects will focus on 1) integration of biological and physicochemical air and water revitalization systems; 2) effect of atmospheric pressure on system performance; 3) planetary resource utilization for ALS systems, in which solid substrates (simulated planetary soils or manufactured soils) are used in selected crop growth studies; 4) environmental microbiology and toxicology; 5) monitoring and control strategies; and 6) plant growth systems design. Included are descriptions of the overall design of the test facility, including discussions of the atmospheric conditioning, thermal control, lighting, and nutrient delivery systems.

NASA Discipline Number 61-10↗