John G. Riemann

Daily cycle of release of sperm from the testes of the Mediterranean flour moth

Abstract A daily rhythm of sperm release from the testes was found in young virgin male Mediterranean flour moths, Anagasta kuhniella, maintained in a 12 hr light, 12 hr dark regimen. Passage of apyrene sperm from the testes began in the latter half of the light phase and that of eupyrene sperm somewhat later; an apparent peak of release occurred near the end of the light phase. A low level of sperm release continued through the night, but none occurred in the first half of the light phase. Maintenance of pupae and adults in continuous light or decapitation shortly after eclosiion greatly reduced the amount of eupyrene sperm released from the testes. Movement of sperm from the testes was not affected by continuous darkness or by severing the abdominal nerve cord.

Sperm maturation in the male and female genital tracts of Anagasta kühniella (Lepidoptera: Pyralididae)☆

Abstract In the testes of the Mediterranean flour moth, Anagasta (= Ephestia) kuhniella (Zeller), a thick sheath forms around the plasma membrane, replacing a series of laminate projections, the radial mantle; but another projection, the satellite body, is retained as an appendage of the sheath. This sheath quickly differentiates into an outer part made up of a series of rings 150 A wide, covered by a thin sleeve, and interrupted on one side by a narrow, dense plate to which the satellite body is attached, and an inner part made up of a mass of lamellae lacking definite orientation. Once the sperm are transferred to the female tract in spermatophores, marked changes occur in the sheath; the satellite body disappears, dense material appears between the inner margins of the radial discs, and the inner sheath differentiates into two distinct portions, both of which have a paracrystalline structure. Once the females deposit their eggs, most of the remaining sperm degenerate and leave empty sheaths. Evidence was found of a normal separation of sheaths and core components within the spermathecal duct, perhaps in preparation of the sperm for fertilization. During this separation, the sheath splits along the line of the dense plate. The sheath of the apyrene sperm was similar to the outer sheath of the eupyrene sperm.

Ultrastructure of the vasa deferentia of the mediterranean flour moth

Each vas deferens of the Mediterranean flour moth, Anagasta kuehniella (Zeller), consists of a short swollen portion immediately below the testis, another swollen portion that forms a seminal vesicle, and an elongate lower portion that empties into one arm of the ductus ejaculatoris duplex. Three types of epithelial cells occur sequentially. Phagocytic cells that engulf debris from the testis form the anterior two‐thirds of the first swollen portion. Tall secretory cells form the distal third of the first swollen region and extend to the seminal vesicles. The secretory cells surround a slit‐like lumen and appear to function as a valve between the two swollen regions. Many membrane‐enclosed secretory granules are stored at the apical ends of the cells and are released into the lumen together with small amounts of the surrounding cytoplasm. The granules remain intact while they are in the male tract. A second type of secretory cell forms the walls of the seminal vesicles and the lower vasa deferentia. These cells produce secretory granules whose contents become dispersed through the semen. PTA‐chromic acid staining indicates that the seminal plasma has a high glycoprotein content. A thin muscle layer is basal to the epithelial cells. Both apyrene and eupyrene sperm undergo some development in the vasa deferentia. The epithelial cells, muscle, and stored sperm all undergo extensive changes with age.

Cytogenetic investigations on radiation and chemically induced dominant lethal mutations in oocytes and sperm of the screw-worm fly

Abstract Adult females containing oocytes in early prophase or early anaphase of the first meiotic division, and day-old males containing mature sperm were exposed to γ-radiation or the alkylating agent, 2,4,6-tris (1-aziridinyl)-s.-triazine (= tretamine). The doses used induced nearly 100% dominant lethals in the reproductive cells. Treated insects were crossed with untreated ones. Eggs were collected and fixed after different periods of development at room temperature. Stained whole-mounts of the embryos were studied to determine: (1) The kind of chromosome aberrations associated with dominant lethal mutations, (2) the stage of development at which the chromosome aberrations appeared, (3) the stage at which development ceased in embryos containing dominant lethal mutations of either maternal or paternal origin, (4) whether damage induced by tretamine was cytologically similar to that induced by ionizing radiations. Dominant lethal mutations are characterized by the presence of chromosome bridges and fragments between dividing nuclei in the embryo, but the stage of development at which these first appear differs with the type of mutagen used. The damage produced by irradiation of meiotic oocytes is evident during the first and second meiotic divisions (which are completed after oviposition) and continues into the early cleavage divisions, at which time development ceases. After treatment of meiotic oocytes with tretamine, the majority of the subsequent meiotic divisions appear normal and the detection of most of the chromosomal damage is first possible in cleavage divisions, or after the treated nucleus undergoes one replication of chromatin material. Treatment of mature sperm with either γ-rays or tretamine does not prevent syngamy. Chromosome aberrations become evident at the first cleavage division. It is obvious that chromosome-breakage phenomena formed the basis of dominant lethality in these cells. Each of these treatments stops embryonic development generally after only a few cleavage divisions. Various types of abnormalities were observed in the embryos. The relevance of these observations to the mode of action of the mutagens, the chromosomal basis of dominant lethality, and the differential sensitivity of the three types of germ cells to these mutagens are discussed.

Localization of the blood—testis barrier in the testis of the moth, Anagasta küehniella

The permeability of the testis of Anagasta kuehniella has been studied by incubating the gonad in vitro with horseradish peroxidase as an electron-dense tracer. The exogenous protein freely penetrates across the complex and thick wall of the gonad at all stages of the postembryonic life (larval, nymphal, and adult stages). It impregnates the testicular fluid but is totally excluded from the interior of the cysts. Even the dividing gonia and the young spermatocytes appear isolated from the surrounding fluid. Consequently, and in contrast to other cases studied up to now, very few germ cells can be reached by exogenous macromolecules. The primary gonia which are not yet enclosed in the form of cysts and bathe directly in the testicular fluid are the only ones in contact with the tracer. The blood—testis barrier in Anagasta lies therefore exclusively in the cyst envelope. This fact, together with the permeability of the testis wall at all stages of the postembryonic life, is discussed in relation to the hypothetical action of a blood macromolecule on the spermatogenesis of some lipidoteran species.

Abdominally entrained periodicities of testis and vas deferens activity in the Mediterranean flour moth

Abstract In a light-dark (LD) regimen, sperm, first apyrene and then eupyrene, start moving out of the fused testes of the Mediterranean flour moth, Anagasta kuehniella , toward the beginning of the scotophase. At 27° ± 2°C, the sperm mass remains in the proximal part of the vasa deferentia for 10 to 12 hr and then passes rapidly into the seminal vesicles, remains in these organs for about 5 hr, and is then transported to the ductus ejaculatoris duplex where it becomes available for ejaculation. The phases of sperm movement appear to be closely related to sperm development, and the reproductive activity of the moths. In isolated abdomens there is a significant reduction in the amount of sperm released from the testes, but normal periodicity of sperm release and movement continues in either LD or continuous dark (DD) regimens, and rapid phase shifting occurs when a LD regimen is reversed. All stages of sperm movement are disrupted in continuous light (LL), but normal periodicity is usually resumed when isolated abdomens of the LL moths are placed in LD or DD regimens. Normal periodicity also occurs in moths paralyzed with tetrodotoxin or procaine. Removal of any one of the four abdominal ganglia from LL moths does not prevent increased sperm release when the moths are placed in LD, though with each ganglion there is some disruption of the normal pattern of movement down the vasa deferentia. It is thought that the testes and vasa deferentia down to at least the seminal vesicles represent a semiautonomous complex in which periodicity is maintained by endogenous circadian activity in cells of the testes (and possibly the vasa deferentia) or more probably in a peripheral control center.

Ultrastructure of the accessory glands of the Mediterranean flour moth

Five regions are recognized in the accessory glands of the Mediterranean flour moth, Anagasta kuehniella (Zeller), on the basis of cellular morphology and aggregates of secretory material in the lumen. Some variation is found in each of the posterior four regions, especially the third one. In the most anterior region (region 1) the epithelium is composed of a single type of cell, while in each of the other regions there are two classes of cells. The cells of region 1 and one class in each of the other four regions are fairly typical exocrine cells with extensive rough endoplasmic reticula. Secretion is primarily via Golgi‐derived vesicles. Apocrine secretion in the form of sloughing off of the apical cytoplasm probably also occurs in all regions but is most prominent in the posterior two regions. One class of cells is very similar in morphology in each of the posterior four regions though their secretory products form characteristic aggregates in the lumen. The second class of cells (foliate cells) occurring in the posterior four segments is most notably characterized by elongate apical projections that extend out into the lumen. The apical projections contain large quantities of glycogen, some microtubules, and, in some cases, many minute mitochondria. The membrane content of the projections is also very high. In the anterior regions, the membranes are mostly fused in pairs and typically form multilayered whorls. Fusion and whorl formation decrease in the posterior regions. The cytoplasm of the foliate cells has a high organelle content including many lysosomes and mitochondria. The latter exhibit considerable polymorphism, with particular forms occurring in the different regions of the glands. The apical projections of the foliate cells are detached during copulation, presumably as the result of nervous stimulation, and become a part of the ejaculate. Replenishment of all secretory material, including the apical projections, occurs after copulation.

Effects of 20-hydroxyecdysone on sperm release from the testes of the Mediterranean flour moth, Anagasta kuehniella (Zeller)☆

Abstract Abdominal injection of 1 μg aqueous 20-hydroxyecdysone into Anagasta kuehniella , anytime prior to the initiation of sperm release from the testes, prevents the impending release of eupyrene sperm bundles. Apyrene sperm release is not prevented and there is complete recovery of eupyrene release by the following cycle 24 hr later. If 20-hydroxyecdysone is administered on consecutive days, no eupyrene bundles are released and although apryene sperm release continues, it diminishes with time. The effect of 20-hydroxyecdysone in preventing eupyrene release is dose dependent. Administration of decreasing 20-hydroxyecdysone dosages results in increasing numbers of eupyrene bundles released. When a single injection of 20-hydroxyecdysone is administered to isolated abdomens, recovery time of eupyrene sperm release is slower than in whole moths and total recovery is not seen even by 5 days after administration. Apyrene sperm release is also affected to a greater extent than in whole moths, and in some cases, no apyrene release was detected at all. Treatment with 20-hydroxyecdysone prevents cupyrene bundles from passing through the testicular basilar membrane into the vasa efferentia, thus causing a build up of bundles near the basilar membrane but no disintegration of these eupyrene sperm bundles.

Foliate and granule-secreting cells in the ejaculatory duct (simplex) of the Mediterranean flour moth.

The epithelium of the first segment of the unpaired ejaculatory duct (simplex) of the Mediterranean flour moth, Anagasta kuehniella (Zeller), is composed of two types of cells. One type is a typical secretory cell that releases large numbers of granules into the lumen. The other type of cell (foliate cell) forms elongate apical projections that are composed mostly of membranes. The membranes are typically fused in pairs (along their outer surfaces) and form complex multilayered whorls. During copulation the apical projections are split off to become a part of the ejaculate and eventually form a major part of the wall of the males spermatophore. The apical projections of the foliate cells and the supply of secretion from the other type of cell are renewed after copulation.

Ultrastructure of the ductus ejaculatoris duplex of the mediterranean flour moth, Anagasta Kühniella (Zeller) (Lepidoptera : Pyralidae)

Abstract The ductus ejaculatoris duplex serves as the major sperm storage organ in male Anagasta kuhniella (Zeller). The distribution of sperm is not uniform, however. Eupyrene sperm bundles remain near the openings of the vasa deferentia; individual apyrene sperm cells occur throughout the length of the 2 duplex arms. The duplex wall is composed of a columnar epithelium under rather thin layers of visceral muscle. In virgin males, the epithelial cells contain large numbers of dense secretory granules in and around the numerous Golgi complexes. Phagosomes are rather numerous near the apices of the cells, the apparent result of fusion of pinocytotic vesicles. After the duplex is emptied during mating, extensive apocrine and merocrine secretion occurs that results in the accumulation in the lumen of large numbers of dense granules within a mass of fibrous material thought to represent cell lysate formed during apocrine secretion. Pinocytotic activity and phagosome formation also increase greatly after mating. In virgin males there appears to be limited secretion of dense granules, but there is no evidence of apocrine secretion. The duplex secretions may have less to do with sperm storage as such than with the spatial distribution of the components of the semen and the events in the spermatophore after mating. Axons in the muscle layer contain large numbers of neurosecretory granules. Septa at either end of the duplex are composed in part of the secretory cells of the duplex and adjacent organs and in part of specialized partition cells.