Toxic agents research

While there seems to be little in common between intractable epilepsy and cancer, researchers in each field have focused on a common mechanism underlying multidrug resistance a cellular pump called P-glycoprotein (Pgp). Pgp protects cells from toxic substances by actively excreting the toxic agent. The pumps reside in tissues that are extensively exposed to toxic material liver, lungs, kidney, intestine, placenta, and blood-brain barrier. How-... 

A special field not covered in the symposium is that of insecticides, fungicides, and weed killers. Petroleum products are used to an increasing extent as carriers or principal toxic agents, or both. Modem oil research includes work in greenhouses, gardens, and orchards, as well as with automobiles, locomotives, and industrial machines. 

Environmentally induced deteriorations. Currently most emphasis in studies of environmental effects on biological systems is on toxicity and the onset of malignancy. Malignancy is usually directly associated with nucleic acids, but, at least in some cases, nuclear and other proteins may be involved as well. This is an area requiring intensive research. Toxicities usually involve the interaction of the toxic agents with some protein system, particularly enzyme systems. 

In the dormant spore state, endospores are resistant to a wide variety of chemical and physical stresses such as UV and gamma radiation, desiccation, temperature and pressure extremes, and attack by toxic agents (67-70). As they are resilient to most sterilization procedures, bacterial spores are used in several industries as biological indicators (71,72). Certain species can even survive the vacuum, extreme temperatures, and radiation of space (73,74), making them the focus of research concerning planetary protection, panspermia (transfer of life from one... 

Klopping and Van der Kerk (1951) presumed that, analogous to the mode of action of N-monoalkyldithiocarbamates, in the case of ethylene-bisdithiocarbamates, ethylene-bisisothiocyanate is the toxic agent. This decomposition product was detected later by thin-layer chromatography on tomato treated with maneb and in an aerated aqueous solution of nabam (Engst et al., 1968 Engst and Schnaak, 1970). Recently, the attention of the researchers has also turned to the other decomposition products. 

Powell (1946) and Mason (1948) found that the 2 1 complex of 8-hydroxyquinoline with copper, oxine-copper, has a stronger fungicidal action than 8-hydroxyquinoline. Albert et al. (1953) attributed this to the fact that the organic part of the compound makes copper lipoid-soluble and thus accelerates its penetration into the cell. Inside the cell the 2 1 complex dissociates into a 1 1 complex and free 8-hydroxyquinoline. The active toxic agent is the ionised 1 1 complex of nonlipoid properties, which reacts with the enzymes in the fungus and blocks their function. This theory is also supported by the research work of McNew and Gershon (1969). 

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