Evaluation of terrestrial microcosms for assessing the fate and effects of genetically engineered microorganisms on ecological processes

Technical Report · Sat Apr 01 00:00:00 EST 1989

DOI:https://doi.org/10.2172/6294057· OSTI ID:6294057

Fredrickson, J K; Bentjen, S A; Bolton, H Jr; Li, S W; Ligotke, M W; McFadden, K M; Van Voris, P

This project evaluates and modifies the existing US Environmental Protection Agency's Office of Pesticides and Toxic Substances (EPA/OPTS) terrestrial microcosm test system and test protocols such that they can be used to determine the environmental fate and ecological hazards of genetically engineered microorganisms (GEMs). The intact soil-core microcosm represents terrestrial ecosystems, and when coupled with appropriate test protocols, such microcosms may be appropriate to define and limit risks associated with the intentional release of GEMs. The terrestrial microcosm test system was used to investigate the survival and transport of two model GEMs (Azospirillum lipoferum and Pseudomonas sp. Tn5 mutants) to various trophic levels and niches and through intact soil cores. Subsequent effects on nutrient cycling and displacement of indigenous microorganisms were evaluated. The model organisms were a diazotrophic root-colonizing bacterium (A. lipoferum) and a wheat root growth-inhibiting rhizobacterium (Pseudomonas sp.). The transposable element Tn5 was used as a genetic marker for both microorganisms in two separate experiments. The organisms were subjected to transposon mutagenesis using a broad host-range-mobilizable suicide plasmid. The transposon Tn5 conferred levels of kanamycin resistance up to 500 ..mu..g/ml (Pseudomonas sp.), which allowed for selection of the bacteria from environmental samples. The presence of Tn5 DNA in the genome of the model GEMs also allowed the use of Tn5 gene probes to confirm and enumerate the microorganisms in different samples from the microcosms. Two types of root growth-inhibiting Pseudomonas sp. Tn5 mutants were obtained and used in microcosm studies: those that lacked the ability to inhibit either wheat root growth or the growth of other microorganisms in vitro (tox/sup /minus//) and those which retained these properties (tox/sup +/). 53 refs., 7 figs., 6 tabs.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6294057
• Report Number(s): PNL-6850; ON: DE89011359
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ENVIRONMENTAL IMPACTS
EVALUATION
MICROORGANISMS
GENETIC ENGINEERING
ADMINISTRATIVE PROCEDURES
COMPLIANCE
MUTAGENS
REGULATIONS
SOILS
TERRESTRIAL ECOSYSTEMS
TESTING
US EPA
ECOSYSTEMS
NATIONAL ORGANIZATIONS
US ORGANIZATIONS
510100* - Environment
Terrestrial- Basic Studies- (-1989)