Molecular biology techniques action

It should be emphasized that all of these activities proceed simultaneously, and that increased emphasis and interest in any particular area is often preceded by the development of new techniques—for example, the tremendous increase in specificity and sensitivity of chemical methods has proceeded simultaneously with the introduction of molecular biologic techniques into studies of mechanisms of toxic action. 

Upon release from dopaminergic neurons, dopamine exerts its action by interacting with specific dopamine receptors. With molecular biological techniques five subtypes of dopamine receptors have been identified so far. These receptors have been characterised anatomically, and to a certain extent biochemically and pharmacologically. All currently identified dopamine receptor subtypes belong to the superfamily of G-protein-coupled receptors (GPCRs). 

As target resolution increases, the mechanism of action in drug discovery has become much more complex. Assay development methods have used molecular biology techniques to keep pace. Cells expressing recombinant proteins can act as biosensors for real-time analysis of target inhibition in the cell instead of relying on traditional cytotoxicity. These target-, rather than phenotypic-, based assays permit... 

Other physiological studies with the isolated neuropeptides include dose-responses, time-course, mode of action, peptide litres and effects during stress and different stages of development or reproduction crossactivity studies at intraspecies, as well as interspecies levels. Before the advent of molecular biological techniques, more often than not, a neuropeptide was first functionally identified by means of biological assays and subsequently sequenced than the other way around, i.e. very few peptides were sequenced without some knowledge of its function. 

Molecular engineering is a term loosely used to describe the design of enzymes using modem molecular biological techniques to alter their catalytic action. Examples include the following ... 

Animal venoms often contain a number of toxic and nontoxic proteins. Until recently, it would have been practically impossible to collect enough of these materials to develop them as biological weapons. However, many of the venom toxins have now been sequenced (ie, their molecular structure has been determined), and some have been cloned and expressed (ie, produced by molecular biological techniques). Some of the smaller ones could also be produced by relatively simple chemical synthesis methods. The following are examples of the mechanisms of action and sources of venom toxins ... 

In conclusion, observations made in the last few years, especially the binding studies with radiolabeled herbicides, the photoaffinity labeling technique, and the advances of molecular biology have substantially added to our knowledge of the mechanism of action of photosynthetic herbicides. However, many questions also remain to be answered. 

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