Changes in SS linked structures of the sperm tail during epididymal maturation, with comparative observations in sub‐mammalian species

Abstract

Treatment of immature and mature epididymal spermatoz,oa with SDS and DTT reveals differences in the structural character of their respective tail organelles as a function of their maturity, which are riot apparent in untreated spermatozoa. The response of mature sperm tails of rat, rabbit and other mammals to these reagents indicates that the segmented connecting pieces. the coarse outer fibers, the outer membrane of the mitochondrion and the fibrous sheath of the principal piece, as well as the relationships between these organelles, are stabilized highly by intermolecular -SScrosslinks. The disruption of these structures by SDS alone in caput epididymal spermatozoa, however, implies their stabilization by disulfide bonds during sperm passage through the epididymis. Hence the pattern of flagellar beat seen typically i n mature epididy-ma1 or ejaculated spermatozoa is probably determined by post-spermiation changes in the structural as well as in the metabolic properties of the tail organellcs.In similar studies of a wide variety of sub-mammalian species, the sperm tails fell into two broad classes. The "simple" tail, a plasma membrane enclosing only mitochondria and microtubule doublets (teleosts, frog, chicken and pigeon), disappeared immediately in SDS, though a partial -%Sdependent stability was inducible in the microtubules of telcost sperm tails. In the second class, the coarse fibers, arrayed as a nine-membered ring (octopus, snake, lizard, turtle and sparrow) or otherwise (skate, newt), and the fibrous sheath (snake, lizard) also are stabilized by 4 -S -bonds, as is the undulating membrane of the urodele sperm tail.Since the sperm mitochondria in all sub-mammalian species were totally disrupted hy SDS alone, an extreme -S-% dependent stability of the outer mitochondrial membrane may well be a feature unique to mammalian spermatozoa.

Identification and Characterization of Alternatively Transcribed Form of Peroxiredoxin IV Gene That Is Specifically Expressed in Spermatids of Postpubertal Mouse Testis

“…The reduction of sperm disulfides followed by decondensation of sperm chromatin in readiness for fertilization is accomplished in oocytes, which contain high levels of glutathione (38). The thiol-disulfide transition of sperm proteins is a unique feature of eutherian reproduction (39,40). Thus, eutherian sperm nuclei can be decondensed in vitro only by treatment with a denaturing agent and thiols, whereas sperm nuclei of nonmammalian vertebrates or of protherian or metatherian mammals are readily decondensed (40,41).…”

Mammalian sperm metabolism: oxygen and sugar, friend and foe

“…This protein, which in spermatogenesis provides enzymatic protection against lipid peroxidation, becomes the major structural protein in providing the rigid structure, resistant to osmotic swelling in hypotonic media, of mitochondria of the midpiece of mature sperm. Additional stability derives from the large degree of disulfide bond formation that occurs during epididymal transit for mammalian sperm, with most of the structural stabilization being seen in the principal piece (Bedford and Calvin, 1974). The structure of the mammalian sperm mitochondrial capsule stabilizes the inner and outer mitochondrial membranes and so provides an intermembrane space that is, in effect, sperm specific.…”

Pairing of Spermatozoa in the Epididymis of the Opossum (<i>Didelphis virginiana</i>): A Scanning Electron Microscopic Study

“…Although physiological changes (primarily motility) and subtle morphological changes occur during the epididymal maturation of spermatozoa from many eutherian species (BEDFORD, 1963(BEDFORD, , 1975BEDFORD and CALVIN, 1974;BEDFORD, CALVIN and COOPER, 1973;BLANDAU and RUMERY, 1964;CALVIN and BEDFORD, 1971;FAWCETT and HOLLENBERG, 1963;FAWCETT and PHILLIPS, 1969;FRAY, HOFFER and FAWCETT, 1972;GADDUM, 1968), such changes are not nearly as marked as they are in the metatherian forms. The marsupial species are unique in that they exhibit definite changes in morphology (associated with maturation) during their transit through the epididymis.…”