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  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructure of the spermatheca and its associated gland in the ant Crematogaster opuntiae (Hymenoptera, Formicidae) (1994)
    Springer
    Zoomorphology 114 (1994), S. 203-212 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sperm storage by females has reached an extreme degree of development in ants. Ant queens, which are unusually long-lived insects, typically store and maintain an unreplenished supply of viable sperm for ten or more years. The spermatheca of Crematogaster opuntiae includes a receptacle and a discrete pair of accessory, or spermathecal, glands, structures commonly found in sperm storage organs of insects. The bean-shaped receptacle consists of a layer of simple epithelium externally and a cuticular layer internally. In the hilar region, the epithelium is highly columnar and exhibits ultrastructural features characteristic of transport epithelia, such as infolded basal membranes, abundant polymorphic mitochondria, and apical microvilli. The spermathecal glands contain cells that have long, dense microvilli that project into a central lumen, abundant mitochondria, and large fields of glycogen. The valve and pump region of the spermatheca provide a mechanism to conserve sperm by controlling the rate of sperm release. The columnar epithelium may function as excretory tissue that serves to maintain an environment in which sperm can remain viable for many years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00416859
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  • 2
    Electronic Resource
    Electronic Resource
    Reproductive biology of the male leaf-nosed bat, Macrotus waterhousii in Southwestern United States (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 184 (1976), S. 611-635 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The reproductive biology of the bat Macrotus waterhousii was investigated anatomically and physiologically several times monthly throughout the year.The male spermatogenic cycle is initiated in June; sperm are available in August. Testicular hypertrophy is accompanied by increased levels of testicular ascorbic acid and circulating plasma testosterone. Sperm are present in the seminiferous tubules and later the epididymides from August to early December. Regression in testicular size begins in late September and testes are involuted by early December. Levels of testicular ascorbic acid and plasma testosterone decline at this time, although detectable amounts of both are present year-round. Mature sperm are absent from the male tract after late November or early December.The accessory sex gland complex and Cowper's glands undergo an annual cycle in synchrony with the testicular cycle. The accessory complex contains fructose, the concentration of which varies seasonally in direct proportion to glandular hypertrophy. Only trace levels of fructose are elaborated by Cowper's glands.In contrast to vespertilionid bats, where the accessory glands remain enlarged and active when testes involute, those in Macrotus regress.The penis differs structurally from that of other temperate North American bats, primarily by lacking a bony baculum and specialized erectile accessory corpus cavernosus bodies.Males are not reproductively active in their first autumn.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091840403
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  • 3
    Electronic Resource
    Electronic Resource
    Morphological study of the desert heteromyid kidney with emphasis on the genus perognathus (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 194 (1979), S. 461-468 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The renal morphology of three species of desert dwelling Perognathus rodents were compared to Dipodomys and two species of sympatric cricetid rodents. Perognathus has a highly adapted unipolar kidney capable of urine concentration up to 7,500 mOsm/KgH2O. Two major modifications were observed in these kidneys. (1) There is elongation of both the inner and outer medulla. When the thickness of the regions in P. penicillatus are factored by kidney weight it is found that the outer medulla is 3.8 and the inner medulla is 2.2 times greater in length than the extensively studied Dipodomys merriami. (2) There is great variance in glomerular size with approximately 20% of the glomeruli being very large and located in the juxta medullary region. These glomeruli are 1.5-1.6 times greater in diameter than the more numerous superficial glomeruli. These structural modifications are quantitated and the functional implications are discussed particularly in relation to urine concentrating ability in these desert inhabitants.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091940311
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  • 4
    Electronic Resource
    Electronic Resource
    Unique features of the cauda epididymidal epithelium of hibernating bats may promote sperm longevity (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 237 (1993), S. 475-481 
    Details
    ISSN: 0003-276X
    Keywords: Tight junction ; Freeze fracture ; Epididymis ; Hibernating bats ; Sertoli cell-like junctional complex ; Antrozous pallidus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Measurements of extremely high osmolalities in cauda epididymidal fluids of hibernating bat species led to an investigation of the junctional complex morphology of the epithelium of this sperm storage site. Freeze fracture replicas revealed the presence, at certain times of the year, of a tight junction architecture that resembled that traditionally thought to be exclusive to the blood-testis barrier, the strongest permeability barrier in the body. It is hypothesized that seasonal establishment of these specialized Sertoli cell-like tight junctions is necessary to the maintenance of the high osmotic state of the luminal environment, allowing for the prevention of dilution of its contents by paracellular routes and its protection from bursting under the osmotic pressure contained within. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092370406
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  • 5
    Electronic Resource
    Electronic Resource
    The status of the corpus luteum during pregnancy in Miniopterus schreibersii (Chiroptera: Vespertilionidae) with emphasis on its role in developmental delay (1989)
    Springer
    Cell & tissue research 258 (1989), S. 183-201 
    Details
    ISSN: 1432-0878
    Keywords: Delayed implantation ; Delayed development ; Developmental delay ; Corpus luteum ; Miniopterus schreibersii (Chiroptera)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Developmental delay is correlated with torpor in the temperate zone bent-winged bat, Miniopterus schreibersii (latitude 37° S) as a period of pre-implantation delay (delayed implantation) followed by a short post-implantation delay (delayed development). During this time, the number of steroidogenic organelles in luteal cytoplasm is greatly reduced compared with normal embryogenesis, and granular endoplasmic reticulum is prominent. Nidation, which occurs while the animals are hibernating, is not accompanied by marked changes in luteal ultrastructure, although the number of lipid droplets decreases somewhat. Progesterone rises slightly but not significantly; however, a pre-nidation decrease in high 17β-estradiol levels may play a role in implantation. Following implantation, the conceptus remains delayed at the blastocyst stage for several weeks. During this time the bats remain torpid and the only change in luteal cell ultrastructure is an increase in smooth endoplasmic reticulum as differentiation begins toward the trilaminar stage. At the end of developmental delay hypertrophy of the luteal cell begins and mitochondria and lipid droplets increase, markedly. By this time arousal from hibernation has occurred, placentation takes place, and normal development is underway. At placentation, smooth endoplasmic reticulum reaches its maximum in luteal cytoplasm; estrogen and progesterone levels peak about 6 weeks later. For the remaining 2 months of gestation, signs of luteolysis appear. These observations suggest that the corpus luteum of developmental delay, though suboptimally functional, is prolonged in its luteinization by the arrival of winter when the bats enter torpor. The capacity for maximal steroidogenesis is acquired at the end of winter, some weeks after implantation, when arousal occurs and normal development ensues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223157
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  • 6
    Electronic Resource
    Electronic Resource
    Cellular composition and steroidogenic capacity of the ovary of Macrotus californicus (Chiroptera: Phyllostomatidae) during and after delayed embryonic development (1990)
    Springer
    Cell & tissue research 260 (1990), S. 355-366 
    Details
    ISSN: 1432-0878
    Keywords: Delayed development ; Multilaminar follicles ; Corpus luteum ; Steroidogenesis ; Macrotus californicus (Chiroptera)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the leaf-nosed bat, Macrotus californicus, a 4,5-month period of delayed early embryogenesis (October–March) precedes a 3.5-month period of normal embryogenesis (March–June). This prolonged gestation provides a unique opportunity to correlate ovarian changes with the events following implantation. The present study investigated luteal cell development and follicular biology during gestation. Circulating progesterone (P) levels following implantation were unchanged before transition to normal development, and were maximal at the start of active gestation. Luteal cell diameters increased during this period. Serum P levels declined prior to parturition, when cells staining positive for 3β-hydroxy-5-steroid dehydrogenase-5,4-isomerase (3β-HSD) activity were reduced in number and diameter, and enzyme staining was less intense in tissue slices. Subcellular steroidogenic organelles were present during delayed development, but smooth endoplasmic reticulum (SER) was markedly increased after the resumption of normal development at which time also luteal cells reacted positively to staining for 17β-HSD. Before parturition, lipid droplet accumulation and reduced SER suggested a reduction in steroid secretion. Large multilaminar follicles stained positive for 3β-HSD activity throughout gestation and for 17β-HSD except in late delayed development. Thus, the delay in embryogenesis may be due to an inadequately developed corpus luteum or to the steroidogenic activity of the multilaminar follicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318638
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  • 7
    Electronic Resource
    Electronic Resource
    Comparative ultrastructure of ant spermatozoa (formicidae: Hymenoptera) (1990)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 206 (1990), S. 343-350 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mature spermatozoa from spermathecae of founding queens were obtained from 5 species of ants, representing the major subfamilies Myrmicinae (Acromyrmex versicolor, Crematogaster sp.) and Dolichoderinae (Tapinoma sessile, Conomyrma insana, Conomyrma wheeleri). The ultrastructure of ant spermatozoa has many features in common with that of higher insects and is similar to that of other Hymenoptera. Structural similarities to spermatozoa of other Hymenoptera include an acrosome containing an internal rod that extends into the nucleus, two elongate mitochondrial derivatives, a centriolar adjunct, and an axonemal arrangement of 9 + 9 + 2 that includes well-developed coarse, or accessory, tubules. Spermatozoa obtained from A. versicolor, a species that is known to store and utilize viable sperm from this supply for over 10 years, show greater development of the mitochondrial derivatives than do the other species. The most distinctive feature of ant spermatozoa in comparison to other Hymenoptera is the large size of the centriolar adjunct relative to the other organelles. The centriolar adjunct is located posterior to the nucleus, anterior to the mitochondrial derivatives, and opposite the axoneme.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052060311
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  • 8
    Electronic Resource
    Electronic Resource
    Internal reproductive system in adult males of the genus Camponotus (Hymenoptera: Formicidae: Formicinae) (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 211 (1992), S. 307-317 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Descriptions are provided of the histology and ultrastructure of the male internal reproductive tracts from three species of Camponotus, representing three subgenera. This study is the first to provide ultrastructural information on the testes (including spermatogenesis and spermiogenesis), seminal vesicles, and accessory glands in ants. Testes contain about ten follicles each, and each follicle is capable of producing hundreds of cysts in which spermatozoa develop. Structural evidence of meiosis in late pupal testes includes cytoplasmic bridges between spermatocytes, centriole elimination, and fusion of mitochondria. Developing spermatids are in close contact with cyst cells in the region of the acrosome. Mature spermatozoa are similar in ultrastructure to those described previously for two other subfamilies of ants (Myrmicinae and Dolichoderinae). The ultrastructure of the seminal vesicle suggests that it is not merely a passive organ for sperm storage. Large numbers of both mitochondria and membranous whorls suggest a pH-regulating and/or hormonal function. The accessory gland is made up of secretory cells that contain a diversity of secretory granules. SDS-PAGE reveals several proteins found in the accessory glands but absent in the adjacent genitalia. Preliminary analyses indicate that carbohydrate is an important component of accessory gland secretions.
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052110308
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  • 9
    Electronic Resource
    Electronic Resource
    Studies on prolonged spermatozoa survival in chiroptera: A morphological examination of storage and clearance of intrauterine and cauda epididymal spermatozoa in the bats Myotis lucifugus and M. velifer (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 165 (1982), S. 421-434 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The cauda epididymidis, uterine corpus, and cornua and uterotubal junction of Myotis function to retain and preserve normal spermatozoa throughout hibernation. In none of the sites do spermatozoa show features that might account for their extended viability. Spermatozoa stored in the uterus and epididymis show no special orientation toward the epithelium lining these sites, whereas an intimate relationship is established between some sperm and the epithelial cells of the uterotubal junction which might either account for extended postcoital sperm survival or forecast their removal from further participation. Transmission and scanning electron microscopic observations do not disclose any morphological changes in stored luminal spermatozoa. A low rate of phagocytosis of sperm is evident in the female tract during hibernation. However, spermatozoa are evidently not vulnerable to being removed from the storage sites until spring arousal when ovulation occurs. Both uterotubal epithelial cells and phagocytes appear to be involved in the disposal of spermatozoa in the female, whereas epididymal spermatozoa apparently are primarily voided during urination. A mechanism that delays capacitation must underlie the ability of spermatozoa to survive in the female reproductive tract of the hibernating bat.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001650406
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  • 10
    Electronic Resource
    Electronic Resource
    Studies on sperm survival mechanisms in the female reproductive tract of hibernating bats. I. Cytology and ultra-structure of intra-uterine spermatozoa in Myotis lucifugusSupported by research grants from the National Science Foundation and the National Institutes of Health as follows: NSF G-24043 (W.A.W.); NIH RG 6599 C-5 (P.H.K.); NIH AM 09432--01 (L.N.).Shortly after an original draft of this article had been completed, the splendid study of Fawcett and Ito ('65) on the fine structure of bat sperm was published. The overlap between their observations and ours was substantial and we have felt obliged to revise our fine structure section to avoid publishing frankly repetitive material. The present section on ultrastructure is a substantially shortened version of the original. We obviously could not eliminate all redundant observations and still achieve a coherent account, but those retained for the most part complement, differ from, or confirm where this was deemed desirable the observations of Fawcett and Ito. Furthermore, our primary objective has been and is to determine the bases of sperm longevity in the uterus, and our observations of fine structure are focused mainly on intra-uterine sperm, whereas those of Fawcett and Ito dealt wholly with unejaculated sperm from the epididymis. Characterization of the fine structure of surviving sperm in utero as compared with those still within the epididymis is essential to the achievement of our main objective. The section summarizing our microscopic and histochemical observations has not been altered from the original since these observations are not duplicated in the study of Fawcett and Ito. (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 119 (1966), S. 25-59 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Among mammals prolonged survival of spermatozoa in the reproductive tract of the female (circa 7 ± months) is known in only a few species of hibernating bats, but its physiological basis remains obscure. Presumably survival involves special physiological adaptations of the spermatozoa, the uterus, or both. We have initiated studies of sperm survival mechanisms in the hibernating bat Myotis lucifugus involving analysis of the cytology and fine structure of intra-uterine sperm, the morphology and histochemistry of sperm-uterus interactions, and selected biochemical parameters of the reproductive tract. This paper summarizes our findings concerning the morphology of epididymal and intra-uterine spermatozoa, and emphasizes those aspects not detailed by others. The microscopic organization of epididymal sperm is described in detail with particular attention to peculiarities of the head, middle piece and cytoplasmic droplet. The latter contains amylase-resistant PAS+ granules and acid phosphatase, both possibly of lysosomal origin. Most ultrastructural features elucidated by Fawcett and collaborators are confirmed, but additional details concerning the head, post-nuclear sheath, origin of axial filament complex, and the outer coarse fibrils are provided. A functional interrelationship between coarse fibrils 3 and 8 and the longitudinal columns of the fibrous sheath is also postulated.Structural differences between epididymal and uterine sperm are minor, suggesting that uterine environmental factors are most important for sperm survival.A new basis is suggested for the apparent helical arrangement of mitochondria in the middle piece; in Myotis sperm the configuration is illusory, being the result of an orderly alternation in the staining of the serially arranged mitochondrial pairs. We suggest that the “patterned” staining of mitochondria may reflect sequential, cyclic functional alterations of significance in the initiation and/or coordination of the geometrically oriented tail movements.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001190104
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