Structural defense mechanisms

As is clear from the preceding discussion, plants express a vast array of toxic peptides in their defense that are interesting as structural models, active compounds in crop protection, and active compounds in pharmaceutical applications. In the plant kingdom the defense mechanisms involved have produced peptides for many kinds of microorganisms and predators, and in future it is possible that for any new problem in bacterial, viral, or fungal infection, a solution can be found on the basis of leads from plant defense molecules. 

The methylation of DNA at CpG islands has also turned out to be an important regulator for cell development, the differentiated proteome and the regulation of cell survival [237,238]. Indeed the implications of this chemical modification have been linked to DNA accessibility, chromatin fluidity and cell transformation [239,240]. DNA methylation is required for genomic stability and believed to act as an inert epigenetic marker in germinal cells and preimplantation embryos [238]. Presumably, DNA methylation is required for the heritable transmission of chromatin structure, which prevents the expression of terminally silenced genes in differentiated tissues, and provides a host-defense mechanism against parasitic transposable elements [241]. 

The cytokines are of considerable medical importance due to their essential function in controlling the immune system, in defense reactions and for processes of inflammation. Great efforts are therefore being made to elucidate the structure and mechanism of activity of the cytokines and their corresponding receptors and to characterize the components of the signals triggered by cytokines. Many of the cytokines have the cha-... 

Diethylcarbamazine immobilizes microfilariae and alters their surface structure, displacing them from tissues and making them more susceptible to destruction by host defense mechanisms. The mode of action against adult worms is unknown. 

While observing patients during the final months of life, one can see certain defense mechanisms developing in an attempt either to structure death and subsequent "existence" or to deny all possibility of death and assume an eerie positivism that seems surrealistic in character (Field, 1956). The usual clinical approach to death is by a combination of both, and it seems to take an extraordinary toll of a person s ability to relate to his environment and communicate with his family. He becomes isolated and is deprived, to a large extent, of his ability to experience realistically and deeply these last months or weeks of greatest importance in his life. Therefore, interference seems justified if it enables the patient to see and feel with greater intensity. Of course, such medicinal interference must not tamper with the patient s religious ideas and must have the latitude to permit any philosophic interpretation. This study attempts to explore LSD as a means... 

Fifth, two structures may be unable to interact properly if the action of a third structure interferes with them. An example is a neurotic defense mechanism. Suppose, for instance, your employer constantly humiliates you. Suppose also that part of your personality structure has a strong respect for authority and a belief in yourself as a very calm person who is not easily angered. Now your boss is... 

All the classical psychological defense mechanisms can be viewed in these system terms as ways of controlling interaction patterns among perceptions and psychological structures. 

Many structures and subsystems are an intimate part of a person s enculturated personality, however, and are not only highly resistant to change by insight, but may be incapable of being perceived well at all. They are so connected to prepotent needs and defense mechanisms that they cannot be observed clearly, or else they are so implicit that they are outside awareness. They are never observed, so observation and mindfulness techniques do not work. 

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