Chapter 22

A well-constituted plant or animal cell is most certainly equipped with a functional, regulated organization of its impressive array of molecules, and there is no reason to suppose that the coenocytic hypha of a watermold is constructed differently from the cells of other eukaryotes in this regard. Unfortunately, there is a vexatious shortcoming to the collection of facts surrounding the biological occurrence of organic compounds in the Saprolegniaceae. The experimental work at hand is of bits and pieces, and we are thus forced to consider these fragments without a unifying thread of continuity. We have found it expeditious, moreover, to fracture the fragile limits between physiology and biochemistry in the account to follow, although this should not be harmful even if discordant. It will be quite apparent that seemingly limitless opportunities exist for biochemical inquiries into the growth and reproduction of the watermolds, and it is to be hoped that the impetus for exploring the gaps in knowledge will not fall between the physiologist and biochemist and thus be lost. In this chapter and the succeeding one we consider the molecular organization of those few watermolds that have been subjected to the cell biologist’s probing and analysis. We have grouped what is known into a recital of some biological molecules identified in these fungi, their involvement in metabolism, their biosynthesis, and finally their replication. The preoccupation of comparative biochemistry with evolution (the truly unifying theme of consequence in biology) is treated in Chapter 25. Some of the data to which we refer may have little current significance except as historical background, but this impact is sufficient, in our view, to warrant their inclusion.