Bioassays study

Warheit, D.B., B.R. Laurence, K.L. Reed, D.H. Roach, G.A. Reynolds, T.R. Webb, Lung toxicity bioassay study in rats with single-wall carbon nanotubes. Proceedings of the ACS Symposium Series, 890 (Nanotechnology and the Environment), 2005, pp. 67-90. 

Mitchell, D.G., J.D. Morgan, J.C. Cronin, D.A. Cobb, G.A. Vigers, and P.M. Chapman. 1986. Acute Lethal Marine Bioassay Studies for the U.S. Borax Quartz Hill Project. Canad. Tech. Rep. Fish. Aquat. Sci. No. 1480 48-49. 

Boisson, F., M. Gnassia-Barelli, and M. Romeo. 1995. Toxicity and accumulation of selenite and selenate in the unicellular marine algae Cricosphaera elongata. Arch. Environ. Contamin. Toxicol. 28 497-493. Bovee, E.C. and T.L. O Brien. 1982. Some effects of selenium, vanadium and zirconium on the swimming rate of Tetrahymena pyriformis a bioassay study. Univ. Kans. Sci. Bull. 52 (4) 39 44. 

Fox, J.G. (1977). Clinical assessment of laboratory rodents on long term bioassay studies. J. Environ. Pathol. Toxicol. 1 199-226. 

Endocrine Effects. Thyroid hyperplasia and pituitary cysts were observed in rats, but not mice, in a chronic bioassay study with endrin administered in the feed (NCI 1978). Treon et al. (1955) found diffuse degeneration of the adrenal glands in rats dosed with >1.25 mg/kg/day in their feed for 2 years however, the adrenal effects were absent at the 0.25 mg/kg/day dose. There has been no evidence of endocrine effects in occupationally exposed human populations. 

Endocrine Effects. Thyroid hyperplasia and pituitary cysts were observed in rats, but not in mice, in a chronic bioassay study with endrin administered in the feed (NCI 1978). There has been no evidence of endocrine effects in occupationally exposed populations. 

Concentration Plus Solvent Transfer. Concentration of the organic solutes is essential to the determination of many organic contaminants present in water at very trace levels. The solvent transfer is needed for implementation of the separation and detection schemes that do not tolerate the water matrix. For bioassay work, concentration and solvent transfer are also needed because the amounts are too low for direct testing of the water solutions, and dimethyl sulfoxide. (DMSO) is the preferred solvent. In bioassay studies that involve animal exposure, the concentration scheme must accommodate very large volumes of water. Theoretically and practically, these elements of the analytical and bioassay methodologies can be achieved by using solid adsorbents, especially synthetic polymers. 

Although there is strong circumstantial evidence from field, glasshouse and bioassay studies that rust increases the allelopathic ability of ryegrass, many questions remain. An important next step is to identify the allelochemicals concerned. Also, do rusted plants simply produce allelochemicals in higher concentrations or do they produce entirely different allelochemicals to healthy plants Also, what is the allelochemical source in the plant and the mechanism of release to the environment This information will provide a clearer understanding of the influence of pathogens on allelopathy. 

Applebee et al. (1999) found that the toxicity of tall fescue (Festuca arundinacea) infected with Neotyphodium coenophialum increased at elevated concentrations of C02 in the atmosphere. In a bioassay study conducted in sterile sand, Sutherland et al. (1999) applied aqueous extracts from ryegrass to potted clover seedlings. Extracts... 

Haseman, J.K., Melnick, R.L., Tomatis, L., and Huff, J., Carcinogenesis bioassays study duration and biological relevance, Food Chem. Toxicol., 39, 739-744, 2001. 

Field and laboratory studies were conducted to determine the levels of Cd, Pb, and HCBD in various samples collected from a swamp environment in Louisiana and to assess the toxicities of As, Cd, and Hg to two species of aquatic organisms (bluegills and crawfish) indigenous to this swamp [18]. Cadmium and Pb were present in almost all collected samples. Their concentrations in fish were below the action levels set by EPA for the protection of human health. However, hazardous levels of these two elements were found in samples of crawfish, vegetation, soil, sediment, and water to some extent. Low levels of HCBD were recorded in water and sediment samples. In bioassay studies, Hg was found to be the most toxic metal, while As was the least toxic. Between the two test organisms, blue-gills appeared to be more sensitive than crawfish. Mixtures of Cd with As or Hg resulted in a combined toxic effect which was simply additive. However, a synergistic effect was recorded with the mixtures of As and Hg. 

Bioassay Studies of Brassins - BARC As indicated by Mandava (3), bioassay systems have been rather extensively used to study brassins physiology. In addition to the bean 2nd internode bioassay, the bean first internode curvature bioassay (28) and the mung bean epicotyl bioassay (29) were found to be useful by Meudt and Gregory. In many cases, details of early brassins studies using these and other assay systems were not published because the chemical nature of the active component(s) of brassins was unknown at the time. However, types of responses obtained with the synthetic brassinosteroids were essentially the same as those obtained with brassins (29, 30, 31, 32, 33). ... 

Interest in the brassinosteroids grew as a result of these bioassay studies and much cooperative work has been conducted with scientists in various parts of the world using brassinosteroid samples synthesized by M. J. Thompson, USDA, (ret.) (3,31). 

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