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Toxins characteristics

Table 1 Characteristics of biological assays for cyanobacterial toxins... Table 1 Characteristics of biological assays for cyanobacterial toxins...
While it would be difficult to enumerate all of the efforts in the area of implants where plastics are involved, some of the significant ones are (1) the implanted pacemaker, (2) the surgical prosthesis devices to replace lost limbs, (3) the use of plastic tubing to support damaged blood vessels, and (4) the work with the portable artificial kidney. The kidney application illustrates an area where more than the mechanical characteristics of the plastics are used. The kidney machine consists of large areas of a semi-permeable membrane, a cellulosic material in some machines, where the kidney toxins are removed from the body fluids by dialysis based on the semi-permeable characteristics of the plastic membrane. A number of other plastics are continually under study for use in this area, but the basic unit is a device to circulate the body fluid through the dialysis device to separate toxic substances from the blood. The mechanical aspects of the problem are minor but do involve supports for the large amount of membrane required. [Pg.259]

Saxitoxin composition therefore originates as that of the local dinoflagellate population and evolves with time depending on the characteristics of the filter-feeders and subsequent consumers that accumulate and transform the toxins. [Pg.43]

Some Formal Considerations. As with most natural toxins, detection methods for the saxitoxins are an essential prerequisite for most studies of them, as well as for monitoring programs to ensure the safety of food products that may contain them. Furthermore, the degree of success of such efforts is dependant on the characteristics of the detection method used. Detection of the saxitoxins is particularly challenging because of the large number of different but related compounds that must be dealt with, the low levels that must be detected, and their chemical characteristics. Given these factors it is useful to dwell briefly on some underlying principles. [Pg.43]

The PSP toxins represent a real challenge to the analytical chemist interested in developing a method for their detection. There are a great variety of closely related toxin structures (Figure 1) and the need exists to determine the level of each individually. They are totally non-volatile and lack any useful UV absorption. These characteristics coupled with the very low levels found in most samples (sub-ppm) eliminates most traditional chromatographic techniques such as GC and HPLC with UVA S detection. However, by the conversion of the toxins to fluorescent derivatives (J), the problem of detection of the toxins is solved. It has been found that the fluorescent technique is highly sensitive and specific for PSP toxins and many of the current analytical methods for the toxins utilize fluorescent detection. With the toxin detection problem solved, the development of a useful HPLC method was possible and somewhat straightforward. [Pg.67]

Figure 5. Enzymatic transformation of the PSP toxins in the littleneck clams. HPLC was used extensively to determine the presence and characteristics of these conversions. (Reproduced with permission from Ref. 15. Copyright 1983 Academic Press, Inc.). Figure 5. Enzymatic transformation of the PSP toxins in the littleneck clams. HPLC was used extensively to determine the presence and characteristics of these conversions. (Reproduced with permission from Ref. 15. Copyright 1983 Academic Press, Inc.).
It is a supposition that the )9-sheet structure of neurotoxin is an essential structural element for binding to the receptor. The presence of -sheet structure was found by Raman spectroscopic analysis of a sea snake neurotoxin (2). The amide I band and III band for Enhydrina schistosa toxin were at 1672 cm and 1242 cm" respectively. These wave numbers are characteristic for anti-parallel -sheet structure. The presence of -sheet structure found by Raman spectroscopic study was later confirmed by X-ray diffraction study on Laticauda semifasciata toxin b. [Pg.338]

Streptococcus pyogenes can be an extremely dangerous pathogen it produces a series of toxins, including an erythrogenic toxin which induces a characteristic red rash, and a family of toxins which destroy the formed elements of blood. [Pg.26]

According to a strict reading of the characteristics established by the U.S. EPA and the State environmental agencies, all of these items are hazardous wastes when disposed of, and should therefore be subject to the whole onerous spectrum of handling, transportation, and disposal requirements that have been established for toxins, carcinogens, mutagens, explosives, and other wastes that are threatening to health and the environment. [Pg.1215]

Different EHEC serotypes are often found in ruminant populations, but most of the research to elucidate the effect of feed type on EHEC prevalence has been based on serotype 0157 H7. The preference for this pathogenic strain is due to its public health importance, its unique phenotypic characteristics that allow a relatively easy identification compared to other serotypes and the fact that ruminants are its most important natural reservoir. Shiga toxin-producing E. coli (STEC) are a larger group that includes EHEC and have also been found in ruminant populations in relatively large prevalence. Because the pathogenicity of most STEC has not been proven, we will focus our discussion on serotype 0157 H7. [Pg.183]

Figure 21.2 illustrates the basic structure of these common two-subunit toxins, showing schematically their major characteristics. The molecular model of ricin is from Rutenber et al. (1991), RSCB structure No. 2aai. [Pg.828]


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See also in sourсe #XX -- [ Pg.46 ]




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