Bioassays microbial tests

Quantal toxicity tests employing organisms such as daphnids or fish do not alter the concentration of contaminant(s) in a given volume of water because they are directly introduced into their respective experimental containers. In contrast, bioassays undertaken with algae and bacteria somewhat dilute the test material since they must be introduced into test containers (i.e., flasks, tubes or microplate wells) via a certain volume of inoculum. In such tests, the volume share of the test culture can sometimes reach 20 % in the test preparation, which corresponds to a dilution of 1 1.25 (Tab. 2). This dilution stage is therefore the highest concentration that can be examined with such microbial tests. 

See also Bioassays Oven/iew Microbial Tests. Clinical Analysis Overview. Food and Nutritional Analysis Overview. Forensic Sciences Overview Drug Screening in Sport. History of Analytical Science. Microscopy Overview. Spot Tests. Structural Elucidation. 

See also Bioassays Overview Microbial Tests Bioautography. Blood and Plasma. Fluorescence Clinical and Drug Applications Food Applications. Food and Nutritional Analysis Dairy Products. Gas Chromatography Mass Spectrometry. Immunoassays, Techniques Enzyme Immunoassays. Liquid Chromatography Normal Phase Reversed Phase Food Applications. Microbiological Techniques. Radiochemical Methods Food and Environmental Applications. Vitamins Fat-Soluble. 

The GLP requirements for mixtures with carrier (40 CFR 160.113) were originally intended to address problems associated with the incorporation of test and control substances into feed, water, and other media for toxicology studies however, now these same requirements pertain to all other GLP-required studies, including those pertaining to re-entry and worker safety. The requirement involves (1) substantiation of test, control, and reference substance concentration through periodic analyses (2) verification of homogeneity and (3) determination of stability and, if applicable, also solubility. All of these requirements usually require chemical analysis, although bioassay may be necessary for microbial pesticides. 

Planet, and, microbial responses with the sucroae esters. In addition to the above we have conducted experiments on the effects of the sucrose esters on plants and microorganisms and we report these data for the first time. However it should be reiterated that the sucrose esters were composed of acetic (C2) 2- and 3-methylbutyric (C5) and 3-methylvaleric (C6) acids and only the glucose molecule was ester if ied the fructose portion remained in the free hydroxyl state. Also the sucrose esters were extremely difficult to separate so that mixtures were initially obtained and tested. We shall see in the wheat coleoptiles bioassay that as the number of 3-methylvalerate residues decreases in the glucose moiety so the level of biological activity decreases at the 10 4 M level though in all cases there is 100Z inhibition at 10 3 m (Figure 7). 

The first step in the tier system of genetic toxicology blind bioassay testing is the Salmonella, microbial (Ames) test. 

Because of the low cost of this bioassay test ( 500-1,000/chemical) relative to the often unpredictable and always more costly demands of chemical analysis, most chemicals are bioassayed by Salmonella before they are chemically analyzed. Plans call for 300 chemicals to be tested in the microbial system in FY-80 with a eventual goal of 1,000 bioassays of new chemicals a year by 1983. Test chemicals producing positive, ambiguous and selected negative bioassay results are then subjected to comprehensive chemical analysis. An important aspect is that the separation technique used in the chemical analysis must insure ... 

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