Toxins microbial

Bacteria and protozoa in water can produce toxins that can cause illness or even death. Toxins prodnced in rivers, lakes, and reservoirs by cyanobacteria including Anabaena, Microcystis, and Nodularia have cansed adverse health effects in Australia, Brazil, England, and elsewhere in the world. There are abont 40 species of cyanobacteria that produce toxins from six chemical gronps. Cylindrospermopsin toxin (below) prodnced by cyanobacteria has poisoned people who have con-snmed water contaminated by the toxin. Surface scums of cyanobacteria are likely to have especially high levels of cyanobacteria toxins. 

Most of the protozoans that prodnce toxins belong to the order dinoflagellata, which are predominantly marine species. The cells of these organisms are enclosed in cellulose envelopes, which often have beautiful patterns on them. Among the effects caused by toxins from these organisms are gastrointestinal, respiratory, and skin disorders in humans mass kills of various marine animals and paralytic conditions cansed by eating infested shellfish that can afflict humans, sometimes with fatal consequences. 

The marine growth of dinoflagellates is characterized by occasional incidents in which they multiply at such an explosive rate that they color the water yellow, olive-green, or red by their vast numbers. In 1946, some sections of the Florida coast became so afflicted by red tide that the water became viscous, and for many miles, the beaches were littered with the remains of dead fish, shellfish, turtles, and other marine organisms. The sea spray in these areas became so irritating that coastal schools and resorts were closed. 

This is a large subject that can only be dealt with in the barest outline in the present text. Many antibacterial and antifungal compounds have been discovered in microorganisms, and some of them have been successfully developed as antibiotics for use in human and veterinary medicine. They lie outside the scope of this book. A considerable number of other microbial compounds act as insecticides, acaricides, or herbicides, although few of them have been developed commercially (Copping and Menu 2000, Copping and Duke 2007). 

Organic Pollutants An Ecotoxicological Perspective, Second Edition 

Structures of spider toxins that antagonise insect muscle glutamate receptors (and glutamate receptors of other animals) 

Aflatoxin Bj, from Aspergillus flavus growing on peanuts (Arachis hypogea) 

FIGURE 1.3 Some toxins from animals and microorganisms. 

The term microbial toxin is usually reserved by microbiologists for toxic substances produced by microorganisms that are of high molecular weight and have antigenic properties toxic compounds produced by bacteria that do not fit these criteria are referred to simply as poisons. Many of the former are proteins or mucoproteins and may have a variety of enzymatic properties. They include some of the most toxic substances known, such as tetanus toxin, botulinus toxin, and diphtheria toxin. Bacterial toxins may be extremely toxic to mammals and may affect a variety of organ systems, including the nervous system and the cardiovascular system. A detailed account of their chemical nature and mode of action is beyond the scope of this volume. 

The range of poisonous chemicals produced by bacteria is also large. Again, such compounds may also be used for beneficial purposes, for example, the insecticidal properties of Bacillus thuringiensis, due to a toxin, have been utilized in agriculture for some time. 

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Antibiotics (qv) have been fed at subtherapeutic levels to promote mminant animal growth. Possible reasons for the observed growth include decreased activity of microbes having a pathogenic effect on the animal, decreased production of microbial toxins, decreased microbial destmction of essential nutrients, increased vitamin synthesis or synthesis of other growth factors, and increased nutrient absorption because of a thinner intestinal wall... 

Cyc1oadditiORE between chloroketcnes and electron-rich double bonds occur very easily. The microbial toxin moniliformin (10) has been made using this reaction,... 

Microbial toxins such as diphtheria toxin and activated serum complement components can produce large pores in cellular membranes and thereby provide macromolecules with direct access to the internal miheu. 

Deguchi, T. Urakawa, N. Takamatsu, S. Animal, Plant Microbial Toxins 1976, 2, 379. 

Deguchi, T. Urakawa, N. Takamatsu, S. In Animal, Plant, and Microbial Toxins, Vol. 2, A. Ohsaka K. Hayashi Y. Sawai Eds. Plenum Publishing Cor-... 

Neutralization. Small soluble complexes neutralize microbial toxins. 

Sophisticated and veiy sensitive methods have been developed in the food industry for detecting many other microbial toxins. For example, aflatoxin deteetion in seedstuffs and their oils is performed by solvent extraction, adsorption onto columns containing selective antibodies for them, and detected by exposure to ultraviolet light. 

Microbial risks are mostly due to single exposures (except for microbial toxins) chemical risks are affected by chronic duration of exposure. Responses to infective pathogens are probably more variable as compared to chemical agents due to different subpopulations and depending on immune status. 

After all the answers from the interviews had been uploaded, an expert analysed each supply chain for each of the seven defined criteria for quality and safety microbial toxins and abiotic contaminants potential pathogens natural plant toxicants freshness and taste nutrient content and food additives fraud social and ethical aspects. For example, an expert on freshness and taste would check each major step in a supply chain for tomatoes to determine if it fulfilled the definition of a CCP (HACCP, Principle 2) in relation to freshness and taste for this commodity. If the step was considered to be a CCP, the answers in the questionnaire that related to relevant substeps at this step would be reviewed, to assess the control procedures that were in use for this CCP. The expert would then fill in the text field, structuring the input to consist of the following points ... 

Volume 165. Microbial Toxins Tools for Enzymology Edited by Sidney Harshman... 

Sansonetti PJ Microbes and microbial toxins Paradigms for microbial-mucosal interactions. III. Shigellosis From symptoms to molecular pathogenesis. Am J Physiol Gastroin-test Liver Physiol 2001 280 G319-G323. 

A. Taylor, in Microbial Toxins, Volume VII, Algal and Fungal Toxins, S. Kadis, A. Ciegler and S.J. Ajl (eds), Academic Press, New York, 1971, 337-376. 

Busch, C. and Aktories, K., Microbial toxins and the glycosylation of Rho family GTPases, Curr. Opin. Struct. Biol., 10, 528-535, 2000. 

Sakaguchi, G., Molecular structure of Clostridium botulinum progenitor toxins, in Portland, A.L., Dowel, V.R. and Richard, I.L., eds.. Microbial Toxins in Foods and Feeds. Cellular and Molecular Modes of Action, Plenum Press, New York, pp. 173-180, 1990. 

Over the last few decades, safety has become one of the most important topics related to food. From this view, quality control of vegetable raw materials has at first to cover the following issues natural and anthropogenic contaminants (e.g. heavy metals, pollution from industrial and private combustions, not professionally deposited waste products, radionuclides), residues of fertilisers (e.g. nitrate), plant-conditioning and plant-protective agents, filth, pests, the microbial status and the occurrence of microbial toxins. It is not possible to discuss all these aspects in detail however, with a focus on herbs and spices, two of them should be stressed more thoroughly. For further information, see [8]. 

L. D. Soheel, Biochemistry of Some Foodborne Microbial Toxins, Pap. Symp. No. 09118. New York, 1966. MIT Press, Cambridge, Massachusetts, 1967. 

It is often necessary to purify a particular protein to better understand its role in the nutritional value and physicochemical properties of food. Similarly, many enzymes have been purified to study their effect on the texture, color, flavor, and nutritional value of foods. The purification and characterization of protein-based microbial toxins has been necessary to better understand their mechanisms of action and their roles in food-borne disease. 

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