Ultrastructure and overall organization of ligament sac, uterine bell, uterus and vagina in Paratenuisentis ambiguus (Acanthocephala, Eoacanthocephala) – the character evolution within the Acanthocephala

As an adaptation to their endoparasitic lifestyle, Acanthocephala (Palaeacanthocephala, Eoacanthocephala, Polyacanthocephala, Archiacanthocephala) have evolved a highly specialized reproductive system. Most of our present knowledge of the efferent duct system of the female is based on palaeacanthocephalan and archiacanthocephalan representatives. In order to provide a basis for further elucidating the phylogenetic relationships within the Acanthocephala, we herein describe ultrastructure and overall organization of the ligament sac and efferent duct system in females of Paratenuisentis ambiguus (Eoacanthocephala, Neoechinorhynchida). Only one ligament sac was found. The uterine bell consists of two contractile binucleate syncytia (bell wall syncytium, lateral pocket syncytium), two pairs of contractile cells (lappet cells, uterine bell retractors) and three pairs of noncontractile cells (median cells). The contractile uterus bears four nuclei. The vagina is composed of a syncytial epithelium (four nuclei) and two binucleate sphincters. A comparison of the present findings with literature data leads to the following conclusions: except for the uterine bell retractors, the uterine bell components found in P. ambiguus can be assumed to be autapomorphies for the Acanthocephala. The sheathing syncytium and median dorsal cell belong to the basal pattern (sensu ground pattern) of a palaeacanthocephalan subclade termed the Echinorhynchus‐group in the present study. The median oviduct syncytium and paired uterine bell retractors can be assumed to be basal pattern characteristics of the Archiacanthocephala and Neoechinorhynchida, respectively. The study includes a tabular survey of terminological synonyms used in the literature.     

A review of protonephridial excretory systems in Acanthocephala

Our present understanding of the excretory system of Acanthocephala is largely the result of work done by 5 German scholars: Kaiser, Schepotieff, Meyer, Kilian, and von Haffner. Present studies indicate that a protonephridial system is restricted to the family Oligacanthorhynchidae. However, many members of this family have not had a protonephridial system described. Three nephridial designs have been described: 1) dendritic type, organized as branches of a tree where each final branch terminates in a ciliated bulb; 2) capsular type, in which all ciliated bulbs empty directly into a common chamber; and 3) rudimentary type, consisting of a single cell with a patent ciliary pouch but no ducts to the outside. The first 2 types are a syncytia with 3 nuclei located in the capsule or stem wall and none in the flame bulbs. These excretory systems consist of 2 clusters of flame bulbs that empty separately into an expandable excretory bladder which in turn empties into ducts of the reproductive system. This urogenital system empties to the outside through a gonopore located at the tip of the penis in males and the posterior terminus of the vagina in females. Cilia occur in certain excretory tubes, depending on sex and species, but are unknown in the excretory bladder or ducts leading into it. The rudimentary type consists of a cell whose posterior extension terminates near the bursal lumen, but it is not known if this is significant for the discharge of material. There is no information on the physiology or biochemistry of the excretory system or its products.     

Urogenital vasculature and local steroid concentrations in the uterine branch of the ovarian vein of the female tammar wallaby (Macropus eugenii)

The urogenital vasculature of the tammar comprises 4 major paired arteries and veins: the ovarian, the cranial urogenital, the caudal urogenital and the internal pudendal artery and vein. The ovarian artery and vein and their uterine branches which supply the ovary, oviduct and uterus, ramify extensively. Each anterior urogenital artery and vein supplies the caudal regions of the ipsilateral uterus, lateral and median vagina and cranial parts of the urogenital sinus. The caudal urogenital arteries and veins supply the urogenital sinus and caudal regions of the bladder. The internal pudendal artery and vein vascularize the cloacal region, with some anastomoses with branches of the external pudendal vessels. Anastomoses connect the uterine branch of the ovarian artery with the uterine branch of the cranial urogenital and cranial branches of the caudal urogenital arteries, and connect the caudal urogenital and the internal pudendal arteries. Anastomotic connections between the left and right arterial supply also occur across the midline of the cervical regions of the uteri and the anterior lateral vaginae. Similar connections are seen in the venous system. The uterine branch of the ovarian artery ramifies extensively very close to the ovary, giving a plexiform arrangement with the ovarian veins, and also with the uterine venous system on the lateral side of each uterus. This plexiform structure provides an anatomical arrangement which could allow a local transfer of ovarian hormones from ovarian vein into the uterine arterial supply, and thence to the ipsilateral uterus. Progesterone concentrations in plasma from the mesometrial side of the uterine branch of the ovarian vein are markedly higher than in tail vein plasma, especially during the 'Day 5 peak' early in pregnancy, and also at full term. There is also a marked decrease in progesterone concentration from all sites immediately before birth as previously reported for peripheral plasma. These results support the suggestion of a countercurrent transfer mechanism, at least for progesterone, and possibly other hormones, between the ovarian vein and uterine artery. Such a local transfer could explain the different morphological responses of the endometria of the two adjacent uteri during pregnancy in macropodid marsupial species.     

Ultrastructure of genital system ducts of Diphyllobothrium latum (Cestoda:Pseudophyllidae): the ducts of the female reproductive system

The components of the female reproductive system of Diphyllobothrium latum, including ovary, ovicapt, oviduct, vitelline ducts, vitelline reservoir, vagina, seminal receptacle, ootype with unicellular Mehlis's gland, ootype-uterine duct and uterus were observed with the electron microscope. The epithelium of the female reproductive system ducts consists of a nucleate syncytial layer. Structural differences in apical surface of the ducts, the number of nuclei and organoids in syncytial layer as well as the number of underlaid muscles were revealed. The regional differentiations of the uterus wall were registered. The middle and distal region of uterus was covered with microtriches. The filamentous microtriches were observed in apical surface of vagina. The epithelium of seminal receptacle and distal region of uterus were underlaided by the powerful muscle layers. The fertilization canal was revealed. It was shown that the formation of egg shells implemented by the deposit of vitelline globules in their surface in the ootype-uterine duct. Structural and functional differences of different parts of female apparatus in various groups of cestodes are conditioned by species biology.     

Urogenital system of the spotted hyena (Crocuta crocuta Erxleben): a functional histological study

The unique urogenital anatomy and histology of female spotted hyenas (Crocuta crocuta Erxleben) was reexamined to identify adaptations of "structure" that enable/facilitate urination, mating, and parturition through the clitoris. Unusual features of penile anatomy required for meeting ceremonies and successful mating through a clitoral point of insertion were also examined. As reported previously, the upper urogenital tract of the female spotted hyena is typical of other carnivores and consists of the oviducts, uterine horns, uterine body, and vagina. An anatomically defined cervix is absent, even though a histologically defined transition zone between the uterine body and vagina was demonstrated. Adaptive features of the upper genital tract were a helical-shaped uterine cavity, extensive smooth muscle in the uterus and vagina, and a newly discovered submucosal mucous urogenital gland (SMUG) located immediately caudal to the vagina. The extensive smooth muscle facilitates the expulsion of the large pups at parturition through the recurved birth canal. Secretions of the SMUG provide lubrication and protection for the urogenital mucosa during mating and parturition. Two types of "erections" are suggested by behavioral observations: the common hemodynamic erection required for insertion and thrusting by the male, and phallic "flipping" that commonly occurs earlier in the mating sequence and is sometimes seen during meeting ceremonies. Phallic "flipping" appears to be accomplished by the coordinated contractions of the large ischiocavernosus and retractor muscles acting on the semirigid organ. The extremely thick tunica albuginea and interstitial collagen of the common corporal body of the penis and clitoris gives the flaccid phallus some degree of rigidity even in the resting state in males and nulliparous females. Phallic "flipping" implies a hinge region in which flexibility is the key feature. Such a proximal hinge region of the male and female phallus was defined and was notable for its diminished collagen content. The urogenital sinus traversing the clitoris was specialized for distensibility, thus facilitating receipt of the penis during mating and for passage of the infant to the tip of the glans clitoris, where it emerges at parturition. The morphology of the glans penis is notable for the tapered common corporal body that extends to the distal tip of the glans. This adaptation is suggested to be required for a clitoral (as opposed to a vaginal) point of insertion during mating. Finally, additional segments of erectile tissue devoid of a thick collagenous capsule were demonstrated in the glans penis and glans clitoris, which appear to account for the "partially-locking" of the male into the female during the late stages of a mating sequence. Taken together, it is evident that the unusual sexual behaviors of the male and female spotted hyenas are facilitated by unique structural modifications of the relevant organs.     

Expression of mouse membrane-associated prostaglandin E2 synthase-2 (mPGES-2) along the urogenital tract

Prostaglandin E(2) (PGE(2)) is the most common prostanoid and has a variety of bioactivities including a crucial role in urogenital function. Multiple enzymes are involved in its biosynthesis. Among 3 PGE(2) terminal synthetic enzymes, membrane-associated PGE(2) synthase-2 (mPGES-2) is the most recently identified, and its role remains uncharacterized. In previous studies, membrane-associated PGE(2) synthase-1 (mPGES-1) and cytosolic PGE(2) synthase (cPGES) were reported to be expressed along the urogenital tracts. Here we report the genomic structure and tissue distribution of mPGES-2 in the urogenital system. Analysis of several bioinformatic databases demonstrated that mouse mPGES-2 spans 7 kb and consists of 7 exons. The mPGES-2 promoter contains multiple Sp1 sites and a GC box without a TATA box motif. Real-time quantitative PCR revealed that constitutive mPGES-2 mRNA was most abundant in the heart, brain, kidney and small intestine. In the urogenital system, mPGES-2 was highly expressed in the renal cortex, followed by the renal medulla and ovary, with lower levels in the ureter, bladder and uterus. Immunohistochemistry studies indicated that mPGES-2 was ubiquitously expressed along the nephron, with much lower levels in the glomeruli. In the ureter and bladder, mPGES-2 was mainly localized to the urothelium. In the reproductive system, mPGES-2 was restricted to the epithelial cells of the testis, epididymis, vas deferens and seminal vesicle in males, and oocytes, stroma cells and corpus luteum of the ovary and epithelial cells of the oviduct and uterus in females. This expression pattern is consistent with an important role for mPGES-2-mediated PGE(2) in urogenital function.     

Ultrastructure of the protonephridia of larval Rugiloricus cf. cauliculus, male Armorloricus elegans, and female Nanaloricus mysticus (Loricifera)

The protonephridial system of several Loricifera was studied by transmission electron microscopy. A larval specimen of Rugiloricus cf. cauliculus possesses two protonephridia, which are "capped" frontally by a compact mass of still undifferentiated gonadal cells. Each protonephridium consists of four monociliary terminal cells and four canal cells with a diplosome but no cilia. Because of incomplete series of sections and unsatisfactory fixation, the outleading cell(s) could not be detected. In a male specimen of Armorloricus elegans, each gonad contains two protonephridia that open into the gonadal lumen. Each protonephridium consists of two monociliary terminal cells, each forming a filter, two nonciliated canal cells, and two nephroporus cells. The protonephridial lumina of the latter cells fuse to one common lumen, which unites with the gonadal lumen. Preliminary observations on the protonephridia of a female Nanaloricus mysticus reveal a more complicated arrangement of interdigitating terminal and canal cells. One or two terminal cells form their own individual filter or four cells form a common compound filter. The cilium of the terminal cells of all species investigated are surrounded by a palisade of nine microvilli that support the filter barrier made of an extracellular matrix. An additional filter diaphragm could be traced between the pores in the cell wall of each terminal cell of A. elegans. The urogenital system of the Loricifera differs from that of the Priapulida in that the protonephridia of the former are completely integrated into the gonad, whereas the excretory organs of the latter open into the urogenital duct caudally of the gonads.     

Histochemical studies on Raillietina (Raillietina) johri (Cestoda: Davaineidae). I. Nonspecific and specific phosphatases.

Certain phosphatases have been localized by histochemical techniques in various tissues of a pigeon cestode, Raillietina (Raillietina) johri. Acid phosphatase (AcPase), alkaline phosphatase (AlPase) and adenosine triphosphatase (ATPase) were present in almost all structures: tegument; subtegumental muscles; subtegumental cells; excretory canal; testes; sperm ductules; vas deferens; cirrus sac; cirrus; ovary; receptaculum seminis; vagina; vitelline gland cells; oocytes; uterus; embryonated eggs. AlPase was absent in parenchyma, spermatocytes, spermatids and spermatozoa. AlPase activity was more intense in the tegument of mature gravid proglottides. AcPase and ATPase were visualized in various stages of spermatogenesis of the parasite. ATPase activity was also observed in chromosomes. 5'-nucleotidase (AMPase) activity was restricted to embryonated eggs only. Functional significance of these phosphatases is discussed.     

Genistein regulation of transforming growth factor-alpha, epidermal growth factor (EGF), and EGF receptor expression in the rat uterus and vagina.

Epidemiological reports and laboratory data have associated soy and genistein with reduced incidence of uterine, breast, and prostate cancers, cardiovascular disease and osteoporosis, and lower total blood cholesterol. The aim of this study was to investigate the effect of genistein in the uterus and vagina of rats, focusing our attention on the distribution of transforming growth factor (TGF) alpha, epidermal growth factor (EGF), and EGF receptor. A pharmacological dose of genistein (500 microg/g body weight) injected in rats on days 16,18, and 20 postpartum resulted in significant uterine wet weight gain, with hypertrophy of the luminal and glandular epithelium of the uteri, and squamous epithelium of the vagina in 21-day-old animals. At 50 days of age, hypertrophy was no longer evident in the uterus and vagina. Prepubertal genistein treatment resulted in significantly increased EGF immunostaining in individual stromal cells and reduced EGF receptor immunostaining in blood vessels of the uterus. Genistein-treated rats had decreased TGF-alpha immunostaining in glandular and luminal epithelium and a slight increase in EGF receptor immunostaining in stromal cells of the uterus. This suggests paracrine interaction between cells elevating the level of EGF ligand in the stroma and the EGF receptor in the luminal and glandular epithelium, resulting in uterine hypertrophy. In the vagina, genistein did not cause significant alterations to the EGF-signaling pathway in 21- and 50-day-old rats. We conclude that pharmacological doses of genistein during the prepubertal period can modulate the EGF-signaling pathway in the uterus and exert a uterotrophic response in a short-term manner.     

Epithelial-mesenchymal interactions in uterus and vagina alter the expression of the cell surface proteoglycan, syndecan

The cell surface proteoglycan, syndecan, exhibits molecular and histological dimorphism in the mouse uterus and vagina. In the mature vagina, syndecan is localized at the surfaces of the basal and intermediate cells of the stratified epithelium and has a modal molecular mass of ca. 92 kDa. The uterus expresses a larger form of syndecan (ca. 110 kDa) which is detected at the basolateral surfaces of the simple columnar epithelial cells. We have investigated whether epithelial-mesenchymal interactions influence the expression of syndecan in these organs by analyzing tissue recombinants composed of mouse epithelium and rat mesenchyme or vice versa with monoclonal antibody 281-2, which recognizes mouse syndecan. In tissue recombinants composed of newborn mouse uterine epithelium and rat vaginal stroma, the uterine epithelium was induced to form a stratified vaginal epithelium which expressed syndecan in same the pattern and mass typical of vaginal epithelium. Likewise, rat uterine stroma induced newborn mouse vaginal epithelium to undergo uterine development, and this epithelium exhibited a uterine pattern of syndecan expression. Although stromal cells normally express little syndecan in most adult organs, analysis of recombinants composed of mouse stroma and rat epithelium revealed that both uterine and vaginal mouse stromata synthesized syndecan that was larger (ca. 170-190 kDa) than the epithelial syndecans. A quantitative increase in the amount of stromal syndecan was evident when stroma was grown in association with epithelium in comparison to stroma grown by itself. These data suggest that epithelial-mesenchymal interactions influence the amount, localization, and mass of both epithelial and stromal syndecan.     

Dominant activation of the hedgehog signaling pathway alters development of the female reproductive tract

The role of hedgehog (HH) signaling in reproductive tract development was studied in mice in which a dominant active allele of the signal transducer smoothened (SmoM2) was conditionally expressed in the Müllerian duct and ovary. Mutant females are infertile, primarily because they fail to ovulate. Levels of mRNA for targets of HH signaling, Gli1, Ptch1, and Hhip, were elevated in reproductive tracts of 24-day-old mutant mice, confirming overactivation of HH signaling. The tracts of mutant mice developed abnormally. The uterine luminal epithelium had a simple columnar morphology in control mice, but in mutants contained stratified squamous cells typical of the cervix and vagina. In mutant mice, the number of uterine glands were reduced and the oviducts were not coiled. Expression of genes within the Hox and Wnt families that regulate patterning of the reproductive tract were altered. Hoxa13, which is normally expressed primarily in the vagina and cervix, was expressed at 12-fold higher levels in the uterus of mutant mice compared with controls. Wnt5a, which is required for development of the cervix and vagina and postnatal differentiation of the uterus, was expressed at higher levels in the oviduct and uterus of mutant mice compared with controls. Mating mutant females with fertile or vasectomized males induced a severe inflammatory response in the tract. In summary, overactivation of HH signaling causes aberrant development of the reproductive tract. The phenotype observed could be mediated by ectopic expression of Hoxa13 in the uterus and elevated levels of Wnt5a in the oviducts and uterus.     

Hedgehog signaling plays roles in epithelial cell proliferation in neonatal mouse uterus and vagina

Both the uterus and vagina develop from the Müllerian duct but are quite distinct in morphology and function. To investigate factors controlling epithelial differentiation and cell proliferation in neonatal uterus and vagina, we focused on Hedgehog (HH) signaling. In neonatal mice, Sonic hh (Shh) was localized in the vaginal epithelium and Indian hh (Ihh) was slightly expressed in the uterus and vagina, whereas all Glioma-associated oncogene homolog (Gli) genes were mainly expressed in the stroma. The expression of target genes of HH signaling was high in the neonatal vagina and in the uterus, it increased with growth. Thus, in neonatal mice, Shh in the vaginal epithelium and Ihh in the uterus and vagina activated HH signaling in the stroma. Tissue recombinants showed that vaginal Shh expression was inhibited by the vaginal stroma and uterine Ihh expression was stimulated by the uterine stroma. Addition of a HH signaling inhibitor decreased epithelial cell proliferation in organ-cultured uterus and vagina and increased stromal cell proliferation in organ-cultured uterus. However, it did not affect epithelial differentiation or the expression of growth factors in organ-cultured uterus and vagina. Thus, activated HH signaling stimulates epithelial cell proliferation in neonatal uterus and vagina but inhibits stromal cell proliferation in neonatal uterus.     

Ultrastructure of sperm cells in the female gonoduct of Xiphinema

The ultrastructure of the sperm cells in the female gonoduct of the nematodes Xiphinema theresiae and X. pinoides is described. The nucleus of the sperm cells is composed of several electron-dense clumps of chromatin that is not surrounded by a nuclear envelope. A layer of mitochondria, in which the mitochondrial cristae are only rarely visible, lies around the nuclear material. In the surrounding cytoplasm packets of electron-dense fibres are abundant. The sperm in the uterus have the following surface differentiations: highly intertwined protrusions between adjacent sperm cells, protrusions coinciding with the plication of the inner uterine wall and a slightly undulated surface towards the uterine lumen. It is argued that in the uterus, the sperm cells actively move in proximal direction by a mechanism resembling pseudopodial movement, in which the packets of fibres are involved. In the oviduct, the sperm cells loose their surface protrusions and the packets of fibres gradually become less abundant. Since the oviduct has no pre-formed lumen, the sperm cells appear to wedge their way along by forcing oviduct cells apart.     

THE MECHANISM OF THE NEPHRIDIAL APPARATUS OF PARAMECIUM MUL TIMICRONUCLEATUM : I. Expulsion of Water from the Vesicle

Recent analysis of the mechanism of the nephridial apparatus of Paramecium multimicronucleatum by high-speed cinematography (300 fps at x 250) confirms the observations by electron microscopy (Schneider, 1960) that once the pore is opened, the vesicle is invaginated by adjacent cytoplasm and is emptied by collapsing under pressure from that cytoplasm, aided perhaps by pressure of the fibrils which anchor the ampullae to the excretory canal. There is no indication of active contraction of the vesicle or its membrane. There is no permanent pore to the vesicle. The vesicle is closed by a sealing of the ruptured membrane where it is in contact with the pellicular excretory canal. At onset of expulsion of vesicular fluid the membrane across the basal opening of the excretory canal is ripped along one semicircular portion of the excretory pore and is driven up against the opposite wall as a flap while the water rushes out. A constriction of the vesicular and cell membranes at the base of the excretory canal reseals the opening.     

Polarized exocyst-mediated vesicle fusion directs intracellular lumenogenesis within the C. elegans excretory cell

Lumenogenesis of small seamless tubes occurs through intracellular membrane growth and directed vesicle fusion events. Within the Caenorhabditis elegans excretory cell, which forms seamless intracellular tubes (canals) that mediate osmoregulation, lumens grow in length and diameter when vesicles fuse with the expanding lumenal surface. Here, we show that lumenal vesicle fusion depends on the small GTPase RAL-1, which localizes to vesicles and acts through the exocyst vesicle-tethering complex. Loss of either the exocyst or RAL-1 prevents excretory canal lumen extension. Within the excretory canal and other polarized cells, the exocyst co-localizes with the PAR polarity proteins PAR-3, PAR-6 and PKC-3. Using early embryonic cells to determine the functional relationships between the exocyst and PAR proteins, we show that RAL-1 recruits the exocyst to the membrane, while PAR proteins concentrate membrane-localized exocyst proteins to a polarized domain. These findings reveal that RAL-1 and the exocyst direct the polarized vesicle fusion events required for intracellular lumenogenesis of the excretory cell, suggesting mechanistic similarities in the formation of topologically distinct multicellular and intracellular lumens.     

羚牛(Budorcas taxicolor)部分脏器特点的观察

本文对2只羚牛的雌性生殖器官及肝、肾、脾等脏器进行了形态描述,并与黄牛及羊的相应器官进行了比较,为探讨羚牛的分类地位提供了解剖学资料。     

Anatomy of the reproductive tract of the female African elephant (Loxodonta africana) with reference to development of techniques for artificial breeding

Complete reproductive tracts of 30 female African elephants (5-53 years), obtained during a population reduction procedure, were examined. The reproductive tracts were palpated in situ via the urogenital canal. A plastic speculum (1.3 X 170 cm) was introduced into the canal and dye was injected to simulate the procedure for artificial insemination. The lengths of reproductive tracts (from the vulva to the ovary) ranged from 120 to 358 cm. The length increased with the size and age of the animal. There was a membranous constriction (hymen) with an orifice, less than 2 cm in diameter, between the urogenital canal and the vagina, in 4 primigravid and in all 13 nulliparous elephants. The vaginal orifice of 13 multiparous elephants consisted of ragged folds of mucous membrane surrounding a single opening, 5-19 cm in diameter. The ages at first conception of 4 pregnant elephants with intact hymenal membranes were 10, 12, 13 and 14 years. The hymen was not penetrated as a result of intromission and therefore the site of ejaculation would have been in the urogenital canal of the 4 primigravid elephants.