Biochemistry, comparative nucleic acids

Basch, P.F. (1988) Schistosoma mansoni nucleic acid synthesis in immature females from single-sex infections, paired in vitro intact males and male segments. Comparative Biochemistry and Physiology B 90, 389-392. 

Even 30 years ago paleontology was virtually the only source of information about the periods when common ancestors lived. Indeed, the mammalian fossil record was not particularly good. Early writers on comparative biochemistry, such as Baldwin and Florkin, were limited in their sources. Perhaps the first person to perceive the unique value of the molecular evolution of proteins and nucleic acids was Anfinsen (1959), who wrote of this subject in his important book. However, it appears to have been Zuckerkandl and Pauling who, in 1960—1965, introduced the concept of the molecular clock (for a historical review which is part of a group of important critical papers in an issue of the Journal of Molecular Evolution, see Zuckerkandl, 1987). 

Tracer techniques have revolutionized biochemistry and molecular biology. For example, the availability of isotopically labeled compounds made it possible to demonstrate that macromolecules such as proteins, nucleic acids, and complex lipids are synthesized from simple cellular metabolites and provided many insights into the mechanisms and control of the synthetic events. The utility of radiochemical techniques is afforded by (1) their great sensitivity compared to other analytical methods (Table 3-1) and (2) the fact that they label the atoms of molecules without significantly altering their chemical properties, thus allowing them to be traced or followed from one molecule to another. 

Clearly, the most satisfactory way to decide between conflicting concepts of the structure and nature of the hydrogen bond is to treat quantum-mechani-cally a hydrogen-bonded complex as a single large molecule entity with no truncation and to compare the results obtained for this supermolecule to those obtained for the separated molecules treated in the same approximation. This mode of approach is now possible, and a number of such computations using both all-valence electrons methods and the SCF MO non-empirical procedure have recently appeared. The references pertinent to biochemistry have been listed in Tables I and II. These concern only various hydrogen-bonded amides and the base pairs of the nucleic acids. 

This method is already relatively old and has been used for the past several years in organic chemistry and biochemistry. High kinetic energy (several keV) primary ions, e.g., Ar, bombard a surface on which the sample has been deposited. Under these conditions, ions are extracted from the surface and can be analyzed, Benninghoven and co-workers [102] presented a number of examples carbohydrates, alkaloids, amino acids (and derivatives) and peptides. As with the other methods, both positive and negative ionization modes are possible (Fig. 14). More recently, the same author [103] demonstrated the possibility of studying non-volatile nucleic acids and compared the results obtained with the other desorption methods. Sensitivity limits are on the order of ng. 

The area of membrane transport has always been an interdisciplinary field. Physiologists, biochemists, biophysicists, cell biologists and pharmacologists have all made their contributions to the development of our knowledge in this field, often in collaborative studies. The appearance of this book in the series New Comprehensive Biochemistry is justified perhaps more by the future contributions to be expected from fundamental biochemistry than by the contributions made by biochemistry so far. Our biochemical understanding of the molecular structure and dynamics of the various transport systems is still in a primitive state compared to that for biomolecules like nucleic acids and water-soluble proteins. The editors hope that the publication of this volume may arouse the interest of many biochemists, especially the younger ones, for this field of biochemistry and thus contribute to its development. 

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