Pesticides plant cell cultures

Organophosphate pesticides Plant cell cultures Q fever... 

Use of Plant Cell Cultures in Pesticide Metabolism Studies... 

The use of plant cell cultures in pesticide metabolism studies has a history of only about 20 years, but pioneers of the technique have laid the groundwork for an increasing number of researchers interested in the advantages the cell culture systems offer. Host have chosen to use suspension cultures, because of the ease with which they can be manipulated, and the increased possibility for standardization of conditions from laboratory to laboratory. As an adjunct to whole plant studies cell cultures provide information as to the changes that structural modifications of a basic molecule may have on phytotoxicity, especially in detecting the inherent toxicity of a molecule that fails to penetrate or translocate in a whole plant. 

Pioneers in the use of plant cell systems for studies of xeno-biotic phytotoxicity and metabolism have laid the groundwork for an increasing number of researchers interested in the advantages the cell systems offer (4 6-9). Greater emphasis on the identification of pesticide metabolites formed in whole plants and cell cultures has made evaluation of both systems more meaningful. Although the literature is nearly devoid of studies concerning diaracterization of enzyme systems from plant cell cultures that may be responsible for pesticide metabolism reference to the cell cultures as a convenient source has been made (10). 

Much of the literature on the use of plant cell cultures in pesticide research concerns herbicide metabolism and it will be emphasized here. However the comparative metsbolism of other classes of pesticides in plants and plant cell cultures will also be reviewed. The advantages and disadvantages of plant cell cultures in pesticide metabolism studies will be presented and a prognosis of the future attempted. 

Dosage. The choice of pesticide dosage for use in metabolism studies conducted with plant cell cultures will vary with the plant species and the pesticide however, it is important to establish the phytotoxic response for the conditions under which the metabolism portion of the study is run, since metabolism may be affected by the condition of the cells during treatment (4, 6, 27). In addition, it may... 

Comparative Pesticide Metabolism in Plants and Plant Cell Cultures... 

The examples above serve to illustrate certain generalities that can be drawn from comparative metabolism studies in whole plants and plant cell cultures. All of the comparisons have shown that qualitatively there is little difference in pesticide metabolism in plants and cell cultures - the same compounds are isolated from each system. However quantitative differences either in the rate of conversion to a single product or relative importance of one metabolic pathway over another do occur. Some of these differences may be of biological significance and would require the use of whole plants or plant parts to confirm the quantitative aspects of metabolism. 

In general, studies of pesticide metabolism in cell cultures have shown that metabolism is qualitatively similar to that of the whole plant, but quantitative differences do exist. Whole plants or plant parts need to be used to confirm the quantitative aspects of pesticide metabolism observed in plant cell cultures. However, cell cultures can be used to estimate the phytotoxicity and metabolic fate of chemicals that exhibit poor uptake and mobility in whole plants. Thus, they provide an inq>ortant adjunct to whole plant studies. In addition, higher yields of minor or transitory metabolites can usually be achieved in cell cultures, allowing the determination of a sequence of metabolic steps in a reaction. 

Insoluble residues have been reported as important end-products in the metabolism of other pesticides known to be metabolized by GSH conjugation in higher plants (, 6, 2ii 15). Some insight into the mechanisms of insoluble residue formation was obtained by comparing the metabolism of [ ClPCNB, S-[() C)PCP]Cys and pentachlorothiophenol-UL- C (t" C]PCTP) in peanut root and peanut cell culture (Figure 12). 

Immunoaffinity columns are extremely versatile and have been used for the isolation and concentration of a diverse number of analytes from a wide array of matrices (2). Analytes may include macromolecules such as proteins and receptors or small molecules such as environmental toxins, antibiotics, or pesticides. Matrices may include animal tissues or excreta, plant extracts, cell culture medium, or virtually any milieu encountered in biological work. Because of its value as a research tool, immunoaffinity chromatography has found extensive use by the pharmaceutical industry to purify therapeutic proteins, the food safety community to purify small amounts of toxins from food and as a general tool for analytical chemists to purify analytes for subsequent instrumental analysis. 

Table 2. Comparative pesticide metabolisin by plants and cell cultures... 

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