Field Testing Genetically Modified Organisms Framework for Decisions (1989) / Chapter Skim
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10 Properties of the Environment Relevant to the Introduction of Genetically Modified Microorganisms
10 Properties of the Environment Relevant to the Introduction of Genetically Modified Microorganisms
Pages 113-122
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From page 113... ...
Microbial environments often are less well understood than those of higher organisms because of the difficulties in defining, measuring, and controlling various physical and chemical details of the microenvironment important in establishing introduced microorganisms. More studies of microbial interactions with the environment are needed.
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From page 114... ...
Nutrient Status Energy supply often limits the growth of microbial populations. Organic compounds represent the major energy source for most genetically modified microorganisms currently berg studied.
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From page 115... ...
Biological Factors Microbial predators, parasites, symbionts, and competitors contribute significantly to microbial community structure. Experience from microbial introductions into soil and water environments typically has shown that it is difficult to establish introduced populations at densities sufficient to achieve the desired effect, such as nitrogen fixation in rice paddies (Ready and Roger, 1988)
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From page 116... ...
Laboratory studies with sieved and repacked soil cores tend to underestimate microbial movement by leaching compared with that found in undisturbed soil cores, because natural soil structure has more macrop ores and connecting channeb that reduce its effectiveness as a filter. Groundwater and surface water environments may furnish similar habitats and harbor similar heterotrophic microorganisms.
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From page 117... ...
In estuarine, coastal, and open ocean systems, the ejects of wind, tides, and currents, as well as dispersal by fish, birds, aquatic plants, ~d other organ~srns, must be considered. SUITABILITY OF MICROCOSMS FOR TESTING OF MICROBIAL INTRODUCTIONS It is widely accepted that aquatic and terrestrial laboratory microcosms are useful for examining the fate and effects of introduced microorganisms as wed as their survival and persistence in specific environments.
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From page 118... ...
Some of the ecological processes quantified in microcosms include nutrient leaching (Van Voris et al., 1980, 1983) , nutrient cycling (Harte et al., 1980)
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From page 119... ...
, documents the importance of scale and encourages the use of smaD-scale field tests, when am propriate, to evaluate the potential for larger scale environmental ejects. POTENTIAL EFFECTIVENESS OF MONITORING Many planned introductions of genetically modified m~croorganisms should include appropriate methodology for monitoring the released microorganisms ~ and around the test site.
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From page 120... ...
detection by DNA-DNA hybridization of unique ribosomal sequences in total DNA extracted from communities (Attwood et al., 1988~; (2) detection by microscopy of cells containing a DNA floor hybridized to unique ribosomal RNA sequencer in cells (Giovianni et al., 19883; (3)
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From page 121... ...
For terrestrial environments, the methods include furn~gation, sealing the soil surface, or otherwise making the Introduced rn~croorganism's environment unfavorable for survival. Some fumigants are selective for fungi and do not kill bact~ ria, but methyl bromide has proven effective in controlling plant pathogenic bacteria as well as fungi.
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From page 122... ...
4. Although documented examples of introduced microorganisms that have measurably or adversely altered ecosystem processes are not available, unfamiliar microorganisms should be studied carefully first in the laboratory and then ~ smaD-scale field tests before they are introduced on a broader scale.
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