BIOLOGY OF SPERMATOZOA 



755 



Pollister and Mirsky, 1946; Stedman and 

 Stednian, 1951 ; Felix, Fischer, Krekels and 

 Mohr, 1951 ; Bernstein and Alazia, 1953a, b; 

 Alfert, 1956; Vendrely, Knobloch and Ven- 

 drely, 1957; Ando and Hashimoto, 1958; 

 Felix, 1958). Histone is regarded as typical 

 of somatic chromosomes, whereas prota- 

 mines characterize the nuclei of mature 

 sperm (Daly, Mirsky and Ris, 1951). The 

 two types of basic proteins differ in their 

 solubility and physical properties and in 

 their chemical composition as well; prota- 

 mines are found to have fewer amino acids 

 when compared to histones from the same 

 animal (Daly, Mirsky and Ris, 1951 ) . Both 

 are very rich in arginine. This polyamino 

 acid is reported to constitute some 70 per 

 cent of the protamine, "gallin," of fowl sperm 

 (Fischer and Kreuzer, 1953), and about 50 

 per cent and 30 per cent, respectively, of the 

 solid matter of bovine and human sperm 

 nuclei ( Leuchtenberger and Leuchtenberger, 

 1958). Total amino acid composition and 

 other chemical characteristics of sperm nu- 

 clcoprotein have been reported on numerous 

 occasions (see Sarkar, Luecke and Duncan, 

 1957; Daly, Mirsky and Ris, 1951; Porter, 

 Shankman and Melampy, 1951 ; Dallam and 

 Thomas, 1953) . 



Sperm DNA has been isolated from a va- 

 riety of species and its nucleotide composi- 

 tion determined (Chargaff, Zamenhof and 

 Green, 1950; Chargaff, 1951; Chargaff, Lip- 

 shitz. Green and Hodes, 1951 ; Elmes, Smith 

 and White, 1952). According to Elmes, 

 Smith, and White, the purine and pyrimidine 

 bases of human sperm — guanine, adenine, 

 cytosine, and thymine — are present in the 

 molar ratio of 0.92:1.23:0.84:1.01, which is 

 consistent with the "thymus-type" composi- 

 tion of nucleic acid. The absolute amount of 

 DNA ])er sperm nucleus is measurable, both 

 by direct chemical analysis and by ultra- 

 violet microspectrophotometry (Vendrely 

 and Vendrely, 1948, 1949, 1953; Mirsky and 

 Ris, 1949, 1951 ; Leuchtenberger, Leuchten- 

 berger, Vendrely and Vendrely, 1952; 

 Walker, 1956; Knobloch, Vendrely and Ven- 

 drely, 1957; Leuchtenberger and Leuchten- 

 berger, 1958). Bull sperm contain approxi- 

 mately 3.3 X 10-^ mg. of DNA per nucleus. 

 Of particular significance was the Vendrelys' 

 (1948) demonstration that the sperm nu- 



cleus contains half as much DNA as does 

 the diploid nucleus of the corresponding so- 

 matic cell, thereby giving strong support 

 to the theory that DNA is identical with 

 the substance responsible for hereditary 

 transmission. In a recent study of the 

 sperm of bull and man, the Leuchtenbergers 

 (1958) indicated that, whereas the amount 

 of DNA is constant in gametes from fertile 

 individuals, there is a tendency for DNA 

 deficiency in the sperm from infertile in- 

 dividuals (see also Weir and Leuchten- 

 berger, 1957). This finding is surely of great 

 significance but its cause and meaning are 

 at present obscure. 



The amount of ribonucleic acid (RNA) in 

 sperm nuclei is small, but sufficiently large 

 to be detected. Leuchtenberger, Leuchten- 

 berger, Vendrely and Vendrely (1952) gave 

 a value for bull sperm of about 0.1 X 10~® 

 mg. of RNA per nucleus. 



C. THE LOCALIZATION OF ENZYMES 



The mammalian spermatozoon has a full 

 spectrum of enzymes which enables it to 

 carry on the usual glycolytic and oxidative 

 processes associated with the production of 

 energy (Mann, 1954). In addition, there are 

 relatively specific enzyme systems asso- 

 ciated with movement, others related to 

 fertilization, and still others (e.g., amino 

 acid oxidase) possibly concerned with modi- 

 fication of the substrate wdth which the 

 sperm come in contact. Some of these en- 

 zymes have been tentatively localized in 

 specific regions of the sperm, thereby shed- 

 ding some light on the intracellular activi- 

 ties of the gametes and their constituent 

 structures. 



Since both mechanically separated and 

 naturally ejaculated sperm tails, free from 

 the heads, are capable of motility, oxidation, 

 and glycolysis, it is obvious that the key 

 enzyme systems concerned with these proc- 

 esses are relatively self-contained within the 

 flagcllum (Engelmann, 1898; Cody, 1925; 

 Mann, 1958a). As used here, the term fla- 

 gellum includes the mitochondria-containing 

 middle piece, for without it the tail frag- 

 ment rapidly loses its capacity for metab- 

 olism and motility (Bishop, 1961). The en- 

 zymes wdiich have, by direct or indirect 

 means, been identified in the ram sperm fia- 



