Field assays

Most field assays with seaweed secondary metabolites have used co-occurring palatable seaweeds as assay organisms, while most field assays with invertebrate secondary metabolites have used artificial gel-based diets. Each of these approaches is outlined below. 

Herbivory in the field can vary dramatically over small spatial scales (Hay et al. 1983 Hay 1985, 1991). This high variance will diminish the statistical power of field assays unless treatment and control plants are paired in space. Placing members of a pair within 0.5 m of each other and separating different pairs by 4 m or more has been a commonly used procedure. To acquire data rapidly and thus minimize loss or degradation of compounds, transplants should be placed in areas where fishes are abundant and actively feeding. On coral reefs, the best areas tend to be shallow (3-10 m depths) and topographically complex (Hay 1985). 

Alternatively, this same methodology can be used to make small food pellets with and without compounds that can then be released in the water column where they can be attacked by reef fishes. Feeding observations (number of bites per unit time, mass of pellet eaten, or acceptance versus rejection of the pellet) can be made on paired treatment versus control pellets in either field or laboratory situations (Lindquist et al. 1992 Pawlik et al. 1995 Lindquist Hay 1996). 

Laboratory assays with vertebrates can use the same types of treatment and control foods as described above. However, laboratory assays allow modifications 

Because fishes in the laboratory can be isolated and closely observed, observations of whether they accept or reject a bite of treatment versus control food can be made much more reliably than in the field. Assays of invertebrate chemical defenses have commonly incorporated natural concentrations of secondary metabolites into small bite-sized food pellets that co-occurring predatory fishes had been trained to consume from a pipette. This procedure maximizes fish encounters with the food and thus rapidly allows for a determination of how a metabolite affects feeding once a fish has taken the potential prey into its mouth. 

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FIDAP software package, 7 25 Fidelity, of transmission signals, 11 131 Field assays, enzyme immunoassay kits for, 14 144 Fieldbus, 20 672 impact of, 20 673... 

Siebert, S. T. A., Reeves, S. G., and Durst, R. A. (1993). Liposome Immunomigration Field Assay Device for-Alachlor Determination. Anal. Chim. Acta 282 297-305. 

The development of a convenient field assay for N2 fixation in the late 1960s (Stewart et al, 1967 Hardy et al, 1968) which was rapidly adapted for marine studies (see Capone 1983, 1993), led to a flurry of field efforts in a range of open ocean and shallow water and benthic marine environments. We wiU first summarize some of the recent advances and insights relative to N2 fixation in benthic marine environments, move on to the water column, summarize the controls on N2 fixation and comment on the broader, biogeochemical impacts of N2 fixation. 

Lane A. C. (1908) Mine waters and their field assay. Geol. Soc. Am. Bull, 501-512. 

Active secondary metabolites are often deterrent to more than one predator. Algal secondary metabolites have been shown to deter both sea urchins and fish [67]. Compounds from a Bahamian sponge deter feeding among a natural assemblage of fish [68]. Ascidlans have also been shown to contain a chemical defence against reef fish in field assays [61]. 

Because the selection criteria applied in the screening of haploid populations was clearly related to the carbon economy of entire plant, and also because the significant increase in dry matter production and leaf area per plant of selected genotypes on different field assays (7), the aim of this work was to characterize the photosynthesis and dark respiration of these genotypes in order to know the extent of possible physiological modifications which able them to survive in a low CO2 atmosphere and to yield higher plant production in field conditions. 

Laccase has also been proposed, and utilized, as a method for quantifying the extent to which mold Botrytis cinerea) deterioration has occurred on fruit (Dubourdieu et al., 1984). This colorimetric method relies on laccase-catalyzed oxidation of syringaldazine to its corresponding colored quinone. This test has an additional advantage in that the analysis has been reduced to kit form for field assay. Details of these procedures are described by Zoecklein et al. (1995). 

Broeckling, C.D. and Vivanco, J.M. (2008) A selective, sensitive, and rapid in-field assay for soil catechin, an allelochemical of Centauria maculosa. Soil Biol. Biochem. 40, 1189-1196... 

Two different field assays were developed by Slattery et al. (1995) to examine microalgal settlement. In the first experiment, Antarctic soft coral extracts were incorporated into a 5% agar solution at dry weight concentrations equivalent to... 

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