Chemical defense laboratory studies

Further directions for the study of both meroplankton and holoplankton chemical ecology include development of field bioassays to couple with laboratory studies. Studies are needed to determine how consumers may perceive secondary metabolites produced by plankton.166 The ability of planktonic organisms to sequester defensive chemistry in specific tissues or mucus, as seen in benthic invertebrates, is unknown. Very little is known about the specific compounds responsible for chemical defenses in plankton, and we expect the library of secondary metabolites produced... 

Not surprisingly, although the evolution of sequestered microbial toxins appears to be rather widespread in marine environments, sequestration of defensive alkaloids in the apparent absence of microorganisms may generally characterize the chemical defenses of terrestrial animals. Careful searches for possible microbial syntheses of defensive compounds (allomones) have not been generally implemented, but recent studies in a few laboratories raise the possibility that microbial endosymbionts may be of major importance in the biogenesis of selected insect deterrents. 

Simmons, R. R., Caldwell, J. A., Stephens, R. L., Stone, L. W., Carter, D. J., Behar, I., et al. (1989). Effects of the chemical defense antidote atropine sulfate on helicopter pilot performance A simulator study (USAARL Tech. Rep. No. 89-17). Fort Rucker, AL U.S. Army Aeromedical Research Laboratory. 

Field studies are necessary to validate anti-predator responses of prey fishes in the chemically complex natural environment. While several of the early trap experiments demonstrated the effectiveness of alarm cues in the field (i.e., Mathis and Smith, 1992), the more complicated recent studies often demonstrate no preferential avoidance between familiar and unfamiliar cues or, alternatively, results are contradictory to predictions. Trap experiments have therefore brought into question previous knowledge based primarily on laboratory studies (i.e., visual compensation model). Anti-predator defense strategies of fishes are clearly context-dependent. To decipher and explore the complexities of this dependent response further, field studies investigating the various biotic and abiotic factors affecting a fish s response are required. 

The National Research Council (NRC) of the National Academy of Sciences (NAS) will identity the scientific and technology capabilities that must be available to support Chemical and Biological Defense Program (CBDP) research, development, test and evaluation, and operational activities, and provide guidance on which of these capabilities can be obtained outside the Military Service laboratories, which are unavailable except in the Military Service laboratories, and which are so mission-critical (classified, nonproliferation, or other) that they should be maintained in the Military Ser dce laboratories. It will review relevant Department of Defense (DoD) studies and other pertinent literature, and conduct site visits and interviews with all necessary CBDP and DoD Laboratory stakeholders to collect the data to accomplish the study objectives. It will provide guidance for coordination and... 

The role of chemoreception in antipredator defenses can be demonstrated by comparing the response of intact and chemosensory impaired subjects to predator scents. Laboratory studies indicate that subjects with chemosensory impairments are less responsive to predators than are intact subjects. Naive intact rats presented with cat scent exhibited freezing and micturition more frequently than did rats whose olfactory bulbs had been removed (Sieck et al. 1974). Mollenauer et al. (1974) placed intact and bulbectomized rats in a cage adjacent to a cat separated by a wire mesh. Olfactory-impaired rats exhibited fewer signs of fear, defecating less and exploring more than did intact rats. A similar approach could be implemented in the field, and survivorship of intact subjects could be compared to that with individuals whose chemical senses have been impaired (Weldon 1990). 

The U.S. army experimental studies cited herein were approved by the Animal Care and Use Committee at the U.S. Army Medical Research Institute of Chemical Defense, and aU procedures were conducted in accordance with the principles stated in the Guide for the Care and Use of Laboratory Animals and the Animal Welfare Act of 1966 (P.L. 89-544), as amended. The views expressed in this article are those of the author(s) and do not reflect the official policy of the army, the Department of Defense, or the U.S. government. 

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