Bioassay procedure

Bioassays procedures have been developed in species such as chicks which have been fed a niacin-deficient diet. Due to the fact that, for example, tryptophan is a biological precursor of niacin, niacin can be produced from other sources (55). As a result, the tryptophan content of the diet has to be monitored carefully for accurate results. 

NCRP. 1987. Use of bioassay procedures for assessment of internal radionuclide deposition. National Council on Radiation Protection and Measurements. Bethesda, MD. Report No. 87. 

Several procedures have been reported for extraction of the suspected allelopathic agents from donor plants. Essentially all the procedures that were employed attempted to simulate the routes of entry of toxic substances into the natural environment. As shown previously, the allelopathic agents are released through leaves and roots, or escape into the environment as volatile materials. Table 3 suratBrizes the different extraction and bioassay procedures employed to isolate and detect the toxic chemicals (17). For extraction, the investigators used either the plant parts from the donor plants or the intact donor plants from which the suspected chemicals were leached through leaves, stems or roots. 

When using purified triolein, most samples are amenable to bioassay after di-alytic enrichment. For example, Microtox bioassay of dialysates of SPMDs shows that the SPMDs made with the purified triolein have lower acute toxicities than dialysates from SPMDs made from unpurified triolein (Johnson, 2001). Finally, examination of the dialysates using the yeast estrogen screen (YES) assay (Routledge and Sumpter, 1996) demonstrated that the purification procedure removes all background estrogenic activity (Lebo et ah, 2004). Use of triolein purified by this process expands the potential applicability of SPMD sample extracts to include numerous bioassay procedures (see Chapter 6) and GC-MS as a standard analysis technique. 

The mouse bioassay, an indirect assay, historically has been used to evaluate shellfish toxicity (especially for PSP). Other bioassay procedures have been developed but not generally applied for regulatory purposes (Schantz et al., 1958). The mouse bioassay involves intraperitoneal (i.p.)... 

Unfortunately in our laboratories (46) and in other s (47), the use of chopped lung tissues has appeared excessively laborious, not always reliable and extremely insensitive (48). We subsequently devised a simple, sensitive and reliable bioassay procedure using pig platelets for the assessment of histamine releasing factors in cotton mill dust (46). 

Based on the correlation matrix of all bioassays data obtained with 37 effluents, it can be concluded that none of the bioassays produces data that are redundant. In other words, all bioassay procedures add to the information content of the PEEP index. 

Several short-term bioassay procedures (3-14) have been developed recently which are applicable to detecting mutagenic and potential carcinogenic activity of organic substances. The SaimoneJla/mammalian mlcrosome assay or Ames Test (13-13] has been the most frequently applied and its efficacy has been well documented. This assay has also been applied to complex mixtures (19-22) to reduce greatly the time... 

Sample and Standards Preparation. Shellfish samples were extracted by the standard bioassay procedure (1). Prior to injection into the HPLC, protein was precipitated with 1.5% TCA at I C (60ul) 50% TCA to 2 ml extract). The samples were then centrifuged, an aliquot diluted 1 3 with water and filtered (. 5 urn). 

Mouse Bioassay Procedures. For initial screening and LD50 determinations outbred female swiss mice (Harlan Sprague Dawley ICR BR ) weighing between 19 to 21 g were used. Doses of toxic extract were suspended in 0.5 ml of 0.1% Tween 60 in 0.15 M NaCl and administered by i. p. injection. Mice were observed for a period of 48 hours. 

Bloassay. A bioassay procedure which was referred to as "quick screening test" involving toxicity to fish was selected as a guide to the toxic compounds (16, 17). On this basis, the... 

Takahashi, S. and Kitamura, C. (1972). Bioassay procedure of the sex stimulant of the American cockroach, Periplaneta americana (L.) (Orthoptera Blattidae). Applied Entomology and Zoology 7 133-141. 

Furthermore, many bioassay procedures can be affected synergis-tically or antagonistically by artifacts. In current practice, chemists use various solvents to clean the resin as completely as possible, run a resin blank, and chromatographically analyze the blank sample. Rarely are the artifacts identified. This procedure does not help the biologist who requires a blank that does not show a positive response in the bioassay test of the blank. Biologists usually clean the resin as the chemists do and complete a blank for the bioassay. Artifacts should be identified to assure that the bioassay results are in response to the compounds under study and not the artifacts in combination with the sample. 

Hacklcr, L.R. 1977. Methods of measuring protein quality Areview of bioassay procedures. Cereal Chem. 54 984-995. 

Jo obtain federal registration for the use of gibberellic acid on various crops, the residual concentration at harvest time had to be determined. Zweig and Cosens (7) reported on the use of bioassay procedures in determining residual gibberellic acid in grapes and outlined the total count method for the determination of residual, tritium-labeled gibberellic acid. 

Bioassay procedures for the determination of gibberellic acid have been developed (2, 5), but more recent chemical fluorometric assay methods are equally specific. However, both assay methods show a low response with samples containing less than 10 /x/xg. of the gibberellins. Consequently, in determining residual amounts within the part per billion (p.p.b.) range, relatively large samples must be extracted and extracts partially purified to satisfy the assay conditions. These operations are usually accompanied by some material losses or degradation, which impair quantitative interpretation of the results. Natural inhibitors can influence the results in the bioassay method (2), and fluorescent contaminants can interfere with the spectrophotometric analysis. 

Plants were grown and treated with CCC as in bioassay procedure (15). Two days after CCC treatment, plants were sprayed until wet with gibberellin solutions. Two weeks after CCC treatment lengths between bases of nrst and second leaf blades were measured and expressed as per cent of length for untreated controls. Results are average of several experiments. 

California Department of Fish and Game denotes the State of California Department of Fish and Game, Static Acute Bioassay Procedures for Hazardous Waste Samples, 1988. EPA-600/4-90/027F denotes US Environmental Protection Agency, Methods for Measuring the Acute Toxicity of Effluent and Receiving Waters to Freshwater and Marine Organisms,... 

Electrochemical methods have been used for determinations of species of elements in natural waters. Of the many electrochemical techniques, only a few have proved to be useful for studies of speciation in complex samples, and to possess the sensitivity required for environmental applications. The greatest concern is the measurement of the toxic fraction of a metal in an aqueous sample. The definition of a toxic fraction of a metal is that fraction of the total dissolved metal concentration that is recognised as toxic by an aquatic organism. Toxicity is measured by means of bioassays. Elowever, a universally applicable bioassay procedure cannot be adopted because the responses of different aquatic species to metal species vary. Nevertheless, bioassays should be used as means of evaluation and validation of speciation methods. A condition is that the test species (of the bioassay) should be very sensitive to the metals being studied so as to simulate a worst case situation (Florence, 1992). 

Nisin concentration was measured using a bioassay procedure based on the method of Shimizu et al. (15). A high-performance anion-exchange chromatography method (16) was used for lactic acid analysis. 

Analysis of urine samples for excreted radionuclides is the most prevalent in-vitro bioassay procedure in use today. It is particularly useful for radionuclides that enter the body in a relatively transferable (i.e. soluble) form. When a radionuclide in such a form reaches the bloodstream, fractions will be deposited in various body organs and the remainder excreted, predominantly in the urine. 

Boecker, B. et al.. Current status of bioassay procedures to detect and quantify previous exposures to radioactive materials. Health Phys., 60, Suppl. 1 (1991) 45-100. 

Since the 1950s, the Canadian-United States Conference on Shellfish Toxicology endorsed a mouse bioassay that was based on the use of purified toxins and has historically been the most universally applied technique for examining shellfish (especially for PSP) other bioassay procedures have been developed but not generally applied. The intraperitoneal minimal lethal dose of the toxin for the mouse was 9 pg kg body weight. The intravenous minimal lethal dose for the rabbit was 3-4pgkg body weight. The minimal lethal dose of the toxin for humans is estimated to be between 1 and 4 mg. 

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