Biomedical subjects

C F Atkinson

Publications and source records attributed to C F Atkinson.

6 recordsLinked to original sources

PubMed1999

Extraction and use of nutrients from composted wheat and potato plants.

Human survival on extended-duration space missions will require reliable regenerative life support systems. Biological systems using higher plants could be incorporated into life support systems; however, substantial quantities of inedible crop residues will also be produced. Composting can reduce the volume of crop residues and provide an end product that may be leached to remove soluble nutrients for use in hydroponic plant growth systems. Solubilization can be affected by physical conditions; we investigated several treatments (pH, temperature, agitation, or pretreatment sonication) for aqueous extraction of nutrients from composted inedible potato and wheat biomass. No significant differences were noted in electrical conductivity data. Chemical analyses indicated highly significant differences. Wheat seeds (Triticum aestivum L. cv. Apogee) were germinated in each extract to monitor for potentially inhibitory compounds. Seeds germinated in each extract, but total mean root lengths were affected negatively by sonication before extraction. Aqueous extracts may also support plant growth.

Biomass↗

PubMed1998

Composting in advanced life support systems.

Space missions of extended duration are currently hampered by the prohibitive costs of external resupply. To reduce the need for resupply, the National Aeronautics and Space Administration (NASA) is currently testing methods to recycle solid wastes, water, and air. Composting can be an integral part of a biologically based waste treatment/recycling system. Results indicate that leachate from composted plant wastes is not inhibitory to seed germination and contains sufficient inorganic minerals to support plant growth. Other solid wastes, for example kitchen (food) wastes and human solid wastes, can be composted with inedible plant residues to safely reduce the volume of the wastes and levels of microorganisms potentially pathogenic to humans. Finished compost could serve as a medium for plant growth or mushroom production.

Biodegradation, Environmental↗

PubMed1998

Evaluating the feasibility of biological waste processing for long term space missions.

Recycling waste products during orbital (e.g., International Space Station) and planetary missions (e.g., lunar base, Mars transit mission, Martian base) will reduce storage and resupply costs. Wastes streams on the space station will include human hygiene water, urine, faeces, and trash. Longer term missions will contain human waste and inedible plant material from plant growth systems used for atmospheric regeneration, food production, and water recycling. The feasibility of biological and physical-chemical waste recycling is being investigated as part of National Aeronautics and Space Administration's (NASA) Advanced Life Support (ALS) Program. In-vessel composting has lower manpower requirements, lower water and volume requirements, and greater potential for sanitization of human waste compared to alternative bioreactor designs such as continuously stirred tank reactors (CSTR). Residual solids from the process (i.e. compost) could be used a biological air filter, a plant nutrient source, and a carbon sink. Potential in-vessel composting designs for both near- and long-term space missions are presented and discussed with respect to the unique aspects of space-based systems.

Biodegradation, Environmental↗

PubMed1997

An overview: recycling nutrients from crop residues for space applications.

Without some form of regenerative life support system, long duration space habitation or travel will be limited severely by the prohibitive costs of resupplying air, water, and food from Earth. Components under consideration for inclusion in a regenerative life support system are based on either physicochemical or biological processes. Physicochemical systems would use filtration and elemental phase changes to convert waste materials into usable products, while biological systems would use higher plants and bioreactors to supply crew needs. Neither a purely biological nor strictly a physicochemical approach can supply all crew needs, thus, the best each approach can offer will be combined into a hybrid regenerative life support system. Researchers at Kennedy Space Center (KSC) Advanced Life Support Breadboard Project have taken the lead on bioregenerative aspects of space life support. The major focus has been on utilization of higher plants for production of food, oxygen, and clean water. However, a key to any regenerative life support system is recycling and recovery of resources (wastes). In keeping with the emphasis at KSC on bioregenerative systems and with the focus on plants, this paper focuses on research with biologically-based options for resource recovery from inedible crop residues.

Biodegradation, Environmental↗

PubMed1996

Biodegradability and microbial activities during composting of poultry litter.

Poultry litter is composted to reduce odor and pathogens and to improve its quality as a soil amendment. Organic material, e.g., sawdust, is added to increase the C:N ratio to achieve optimum degradation of organic C and retention of N through microbial biomass formation. However, the relative biodegradabilities of the organic material in poultry litter and the amendment are usually not known. Furthermore, it is assumed that as microorganisms metabolize organic compounds and produce CO2, they increase in biomass and, therefore, retain N. In this study, bench-scale compost reactors were used to determine the relative contributions of poultry litter and of the amendment (sawdust) to the biodegradability of a compost mix. Approximately 29% of the volatiles lost from the poultry litter mix came from the sawdust. Fiber analyses revealed that only a small portion of cellulose was degraded. Although microbial subpopulations able to degrade selected macromolecules were present at varying levels, the overall level of microorganisms did not change markedly. Populations capable of degrading bacterial cell walls were present throughout the composting period, and microbiological assays indicated that inorganic nutrients were available to support limited microbial growth. These results suggest that N compounds and inorganic nutrients are recycled, rather than fixed during composting.

Animals↗

PubMed1988

Serotype-specific monoclonal antibodies against the H12 flagellar antigen of Escherichia coli.

The flagellar filaments of morphotype E isolates of Escherichia coli characteristically possess an apparent helically arranged sheath structure, surrounding the central core of the filament. Re-examination of the type strains of H-serotypes belonging to morphotype E showed that all but serotype H34 possessed the expected morphology. Heterogeneity was observed in both the diameter of filaments from individual morphotype E strains and in the Mr of individual flagellins. There was no apparent correlation between these two features. Monoclonal antibodies (MAbs) of the IgM class were raised against serotype H12 flagella. In Western immunoblotting and agglutination tests, the MAbs recognized the H12 antigen of six isolates with different O:K antigen combinations. The MAbs were H-serotype-specific, with no significant reaction with the H-antigens of other morphotype E strains. The location of the serotype-specific H12 epitope(s) was studied by immunolabelling with colloidal gold markers. The epitope was surface-exposed and appeared to be helically arranged on the flagellar filament. The pattern of colloidal gold labelling was consistent with the possibility that the H12 serotype-specific epitope resides in the apparent sheath structure.

Antibodies, Bacterial↗