Monographs 



71. 



HI POGLAZOV. I l '7.<. MORPHOGENESIS OFT-EVEN BACTERIOPHAGES 



Basel, etc. Monographs in Developmental Biology vol.7. VI, 105 pp., 56 figs., 

 ( , tabs. Sl-r. 54. , $ 16.75, £ 7.85, DM 51.- 



Molccular self-assembly is now generally considered to be basic to the emergence of all 

 macromoleculai structure in biological systems. (Whether one wishes in this context to 

 use the word "morphogenesis", which was originally coined for quite different processes 

 is largel) a matter of taste.) The T-even phages have contributed much to this view, but as 

 far as the reviewer is aware this is the first book to be devoted entirely to their molecular 

 assembly. It is therefore to be welcomed, although it seems to have been written for other 

 specialists in the field and is not very suitable for the uninitiated. 



1 he author and his co-workers have been active in this field for more than a decade, 

 but most of their work was published in Russian. This work is covered extensively in the 

 book, but it is integrated into a review of relevant work by others. The emphasis is on the 

 assembly of bacteriophages from ready-made protein subunits. The molecular-genetic 

 aspects are sketched in as a necessary background. 



Most of the illustrations are original; they mainly consist of diagrams, optical diffrac- 

 tion photographs, and excellent electron micrographs of a variety of structures and their 

 precursors and subunits. 



The'book has no indexes. It is luxuriously produced and therefore rather expensive. 



72. 



B.E.WRIGHT. 1973. CRITICAL VARIABLES IN DIFFERENTIATION 



Prentice Hall, Englewood Cliffs. Concepts of Modern Biology Series. XVI, 109 pp., 



31 figs., 16 tabs., combined author and subject index. $ 7.95, £4.- 



Contents: 1. The importance of metabolite flux; 2. The intermediate metabolism of a 

 model system: the cellular slime mold; 3. Using kinetic models to find the critical 

 variables; 4. Speculations on the evolution of flux control in differentiation 



This book is interesting particularly because it presents a novel viewpoint. Paraphrasing 

 the author's own words, this viewpoint is that enzyme profiles have little functional 

 significance, and that the important parameter for the metabolic state of a cell is net flux 

 of small metabolites through a metabolic pathway (ch. 1). 



Consequently, in ch. 2 she focusses on the consequences for differentiation of metabo- 

 lite availability and metabolic interactions, rather than gene activation and synthesis of 

 isolated enzymes, which so far have attracted most of the attention. The pathways she 

 singles out for particular consideration are those of the synthesis of carbohydrate end 

 products of differentiation in the model system, Dictyostelium. Critical variables are 

 defined as variables which limit the rate of differentiation at particular points in time by 

 directly affecting the rates of reactions essential to end product accumulation. It is argued 

 that enzymes are not critical variables. 



On the basis of these data ch. 3 present a simplified kinetic model of carbohydrate 

 metabolism, and this is then used for computer simulations. This part of the book can 

 only be judged by the specialist. The author's conclusion is that changes in the flux of 

 endogenous metabolites may play a surprisingly prominent role in biochemical differ- 

 entiation. She stresses the heuristic value of (admittedly primitive) kinetic models and the 

 tact that they may give us a new dimension of understanding of complex metabolic 

 systems. 



Finally, ch. 4 speculates on the evolution of closed developmental systems. 



196 



