Clam extract

L/mole). It cross-reacts at >90% with saxitoxin but at <1% with neosaxitoxin. This antibody, when used in an anti-rabbit IgG "second antibody" radioimmunoassay format, can detect pmole quantities of saxitoxin. This assay has been shown to be a simple and efficient method for the analysis of saxitoxin in clam extracts. The lack of antibody cross-reactivity to the neosaxitoxin sub-group of the paralytic shellfish poisons limits the general utility of the assay to neurophysiology studies and to certain clam species which preferentially accumulate saxitoxin. However, the radioimmunoassay serves as a good precursor in the development of an enzyme immunoassay for the paralytic shellfish poisons. 

Note The B and C series of the PSP (R4 - SO ) have not been included in this table because they form their STX, NEO and GTX counterparts (11) on treatment with acid during the preparation of clam extracts. For the structure of tetrodotoxin see (8,9). 

This report describes the development of a radioimmunoassay (RIA) for one of the major PSP (saxitoxin, la) which is based on our successful production of antibodies to a stable saxitoxin derivative-bovine serum albumin conjugate. The application of the RIA to the analysis of PSP contaminated clam extracts and the problems which must be addressed in the development of a routine immunoassay for the PSP are discussed. 

Step 1. Add buffer and test sample to the tube. Total volume 900 ul. The buffer was pH 7.2 phosphate buffered saline. The test samples were STXOL, STX, NEO, TTX or serially diluted clam extract. Step 2. Add labeled STXOL (32 pmoles, 1.2 eq. to sites of specific antibody used, STXOL specific activity - 138 dpm/pmole). 

Continued Development. The RIA will be most useful if it can be used to detect all of the major PSP which are expected to occur in an acidic clam extract (Figure 1). 

Figure 6. A-Chromatogram of toxic butter clam extract showing the presence of the PSP toxins. B-Chromatogram of extract from non-toxic (bioassay) mussels showing the presence of a trace of GTX II, GTX III, and C. Conditions as in Table I with gradient shown in Figure 4.

Proliferating Inhibition of Partially Purified Hard Clam Extract. 381... 

Ohsugi, T., Hidaka, I., and Ikeda, M., 1978, Taste receptor stimulation and feeding behaviour in the puffer, Fugu pardalis. II. Effects produced by mixtures of constituents of clam extracts, Chem. 

The susceptibility of the sulfamates to hydrolysis is intermediate with respect to procedures commonly used for extraction and manipulation of extracts. Quantitative hydrolysis of the pure sulfamate toxins can be accomplished (9) by heating at 100 C for 5 min in the presence of not less than 0.1 M free acid (pH 1 or below). Milder conditions appear insufficient (10). Figure 9 summarizes results from two separate experiments in which samples of nontoxic clam flesh, enriched with constant amounts of saxitoxin Cl (4), were acidified to differing final concentrations of HCl and heated for 5 min at 100 C. The difference between 0.1 M HCl, which would be sufficient for hydrolysis of the pure toxin, and the HCl concentration required to attain plateau toxicity, probably reflects the buffer capacity of... 

Extractable concentrations of sediment-bound zinc were positively correlated with zinc concentrations in deposit feeding clams (Luoma and Bryan 1979). Availability of sediment zinc to bivalve molluscs was higher at increased sediment concentrations of amorphous inorganic oxides or humic substances, and lower at increased concentrations of organic carbon and ammonium acetate-soluble manganese. Zinc uptake by euryhaline organisms was enhanced at low water salinity (Luoma and Bryan 1979). 

There have been many studies on the role of haemocytes in invertebrates, but their role in ingested material is not clear. Haemocytes are the molluscan analogue of the vertebrate macrophage. They are present in the haemolymph and appear to be able to migrate through epithelia, and they are found in the mantle fluid of bivalves and appear to be involved in the uptake of particulate matter. In a study of the clam Tridacna maxima that had been injected intramuscularly with a suspension of carbon particles, it was found that within 24 h the extracted haemocytes were laden with the particles. They had cleared the haemolymph of the particles within 48 h [76], In the tridacnidae some zooxanthellae are... 

We employed various substrates to check for MFO in two bivalve species, a salt water mussel (Mytilus edulis) and a fresh water clam (Anodonta sp). Cytochrome P-450 was also studied. Organisms were exposed to 100 PPM Venezuelan crude in a stagnant system for up to one month. Enzyme assays were carried out with digestive gland 9000 g homogenates (17) and cytochrome P-450 analysis, with microsomes (21). The hydrocarbon substrates investigated included 1I+C-labelled benzo(a)pyrene, fluorene, anthracene, and naphthalene. The method used for separation of BP metabolites by thin layer radiochromatography has been described (7). The metabolite detection method for the other aromatic hydrocarbons was essentially the same except methylene chloride was used as metabolite extractant as well as TLC developer. Besides the hydrocarbon substrates, we also checked for other MFO reactions, N-dealkylase with C-imipramine (22) and 0-dealkylase with ethoxycoumarin (15). 

Hershko, A., Ganoth, D., Pehrson, J., Palazzo, R.E. and Cohen, L.H. (1991). Methylated ubiquitin inhibits cyclin degradation in clam oocyte extracts. J. Biol. Chem. 266,16376-16379. 

Karlin, J. M. (1979). Occupational asthma to clam s liver extract. J. Allergy Clin. Immunol. 63, 197. 

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