Oogenesis and egg shell formation in Heterakis gallinarum (Nematoda)

The structure of the developing ova and egg shell formation of Heterakis gallinarum has been described. The oogonia are small, undifferentiated cells which are arranged around a central cytoplasmic rachis. The oogonia and young oocytes are in cytoplasmic continuity with the rachis and it is suggested that the rachis may influence synchronous development of the oocytes. The oocytes contain two types of granule; refringent, which give rise to the ascaroside layer of the egg shell, and another kind which appear to be a type of yolk for the developing egg. After fertilization the spermatozoon produces numerous ribosomes; a second unit membrane appears beneath the oolemma, and the chitinous layer of the shell forms between the oolemma and this inner membrane. The refringent granules later produce the ascaroside layer of the shell between the chitinous layer and the inner membrane. The outermost layer of the shell is produced from material secreted by the cells of the uterus.     

Developmental and age-related changes in proteins in the female reproductive tract of Heligmosomoides polygyrus (Nematoda)

Proteins in the female reproductive tract of Heligmosomoides polygyrus at days 8, 16, 35, 90, and 140 postinfection (PI) were examined using polyacrylamide gel electrophoresis. Sixteen-day-old and 140-day-old worms also were examined histochemically. Egg production of these worms was assessed for each age group. In analyzing proteins using electrophoresis, the reproductive tracts were separated into 3 sections: the tip, or anteriormost part of tract, containing oogonia; the middle region, containing developing oocytes; and the posterior region, containing the uterus with fertilized eggs. Three major reproductive tract proteins were identified as having molecular weights of greater than 140 kDa, 115 kDa, and 82 kDa. These were found in all parts of the reproductive tract from worms of all ages except those at 8 days PI (which are too young to produce eggs) and are believed to be yolk proteins. Four low molecular weight proteins (L1-4) are believed to be nucleoproteins. L4 was absent from the posterior section of the reproductive tracts and L3 was limited to the posterior sections and may be associated with sperm stored in the uterus. Of 5 high molecular weight proteins the second heaviest, designated H2, appeared to be relatively more concentrated in the posterior sections of the reproductive tract. An 85-kDa protein was limited to the tip and middle sections of reproductive tracts. Histochemical tests on sectioned H. polygyrus showed strong positive reactions for protein in cytoplasmic granules in developing oocytes and in eggs of younger worms (16 days) but a reduced reaction in older worms (140 days). Strains for collagen showed a slight positive reaction in and between developing oocytes and a strong reaction in the egg shells. Stains for nucleoproteins particularly reacted with sperm stored in the uterus, and slightly reacted with fertilized eggs and the nucleoli of the intestinal and ovarian epithelium. Egg production by H. polygyrus increased to 123 eggs/female/day by 16 days PI but declined from 121 eggs/female/day at 35 days PI to 64 eggs/female/day in worms 140 days old. Electrophoresis indicated no loss in the different types of proteins in the reproductive tract of older worms, but histochemistry and protein content assays suggest that older worms that produce fewer eggs contain a relatively smaller amount of protein in the female reproductive tract.     

Microscopic structures of the ovary and female genital ducts of Supachai's caecilian,Ichthyophis supachaii Taylor, 1960 (Amphibia: Gymnophiona)

The structures of the female reproductive system (ovary, oviduct and cloaca) of Ichthyophis supachaii were investigated by dissection, histology and light microscopy. Paired, elongated, sac‐like ovaries are parallel to the gut and fat bodies. Follicle stages include germinal nests of oogonia and primary oocytes, early and late previtellogenic follicles, early and late vitellogenic follicles and atretic follicles. Germinal nests of oogonia comprise oogonia and prefollicular cells. Nests of primary oocytes contain clusters of synchronously developing primary oocytes enclosed by connective tissue. Primary oocytes are associated with follicular cells. Previtellogenic follicles initially form the vitelline envelope, theca cell layers and patches of ooplasmic glycoproteins. Vitellogenic follicles contain heterogeneously sized spherical yolk granules. Atresia is present in several stages of developing follicles. The oviduct is divided into the anterior, middle and posterior parts. All oviductal parts are lined by non‐ciliated epithelium. A small number of mucous cells are present in the middle part. The cloaca of female I. supachaii is divided into the anterior and posterior chambers. The anterior chamber is lined by glandular stratified columnar epithelium, while the posterior chamber has stratified cuboidal epithelium with less mucus production. Our results contribute to useful information on the reproductive biology of caecilians.     

Oviductal morphology and egg shelling in the oviparous lizards Crotaphytus collaris and Eumeces obsoletus

Morphological changes occurring in the oviduct and epithelial cells of the lizards Crotaphytus collaris and Eumeces obsoletus during the natural reproductive cycle were examined and quantified. Additionally, development of the eggshell at different stages of gravidity was described. The anterior uterus of each species has a distinct glandular type which differs between species: in E. obsoletus, the glands are tubular and in C. collaris, branched saccular. The branched saccular glands in the anterior uterus of C. collaris produce collagen-like material that forms the fibers of the shell membranes. However, fibers from the eggshell of E. obsoletus did not stain for collagen. The shell of both species is composed of a multilayered inner boundary covered externally by fibers of varying thickness. Initial layers are composed of thick fibers all lying along the same general axis. Outer layers of fibers are progressively thinner and an external surface layer composed of glycosaminoglycans (GAGs) is also present. In C. collaris, calcium, which is deposited in relatively small amounts on the shell surface, appears to be secreted by the epithelium of the anterior uterus. The nonciliated secretory epithelial cells covering the villi-like folds of the posterior infundibulum secrete GAGs. Epithelial cell height of the infundibular villi is greatest during early gravidity. A functional relationship may exist between luteal activity and oviductal secretory activity because the activity of the glandular epithelium varied as gravidity progressed.     

Histology and functional morphology of the oviduct of an oviparous snake,Diadophis punctatus

Oviductal functional morphology remains poorly understood in oviparous snakes, particularly in regard to oviductal formation of albumen and the eggshell and to sperm storage. The oviduct of Diadophis punctatus was examined using histology and scanning electron microscopy to determine oviductal functional morphology throughout the reproductive cycle. The oviduct is composed of four morphologically distinct regions: infundibulum, uterine tube, uterus, and vagina. The infundibulum is thin, flaccid, and lined with simple ciliated cuboidal epithelial cells. The tube contains ciliated and secretory epithelial cells, which reach a maximum height and hypertrophy during early gravidity and produce glycosaminoglycans. The posterior portion of the tube contains temporary sperm storage receptacles. The uterus retains eggs throughout gestation and secretes the eggshell constituents. The endometrial glands of the uterus hypertrophy during vitellogenesis and become depleted of the secretory granules during gravidity. The functional morphology of the oviduct therefore shows cyclical changes that are correlated with eggshell formation. The vagina consists of thick longitudinal and circular smooth muscle layers, which may serve in retention of eggs during gestation. Furthermore, the vagina contains long furrows in the mucosa that serve as sperm storage receptacles. These receptacles store sperm following fall mating and overwintering, whereas the receptacles in the tube are utilized briefly during vitellogenesis just prior to ovulation. © 1996 Wiley-Liss, Inc.     

Morphology of the reproductive tract in a lizard exhibiting incipient viviparity (Sphenomorphus fragilis) and its implications for the evolution of the reptilian placenta

The morphology of the female reproductive tract and corpus luteum is examined in Sphenomorphus fragilis, a lizard from the lowland regions of New Guinea exhibiting incipient viviparity. Females oviposit eggs that hatch either immediately or within a few hours. Corpora lutea form from ovulated follicles and decrease in diameter as embryonic development progresses. The oviduct from vitellogenic females is sparsely populated with well developed uterine glands containing secretory granules. The eggs are covered with a relatively thin shell (10 μm thick) composed of an inner boundary layer and proteinacous fibers. The secreted shell is complete by early neurulation. Shell morphology does not change throughout the remainder of the in utero incubation period. A well vascularized uterus and chorioallantoic membrane provide simple placentation. These findings suggest that the reduction in shell thickness associated with the evolution of a placenta is due to a decrease in the number of shell glands in the uterus and is not a delay or inhibition of the shelling process per se. This hypothesis further suggests that the selective forces favoring shell gland loss act on the vitellogenic female during gland recruitment which occurs prior to ovulation and not on the pregnant female. © 1992 Wiley-Liss, Inc.     

Reproduction and sexual development in a freshwater gastrotrich

Summary Post-embryonic development of parthenogenic eggs of Lepidodermella squammata was studied by light and electron microscopy in animals of known age and reproductive history. Each bilateral gonad initially contains eight cells. No mitotic proliferation occurs during parthenogenic egg development. Germ cells are tightly clustered, have smooth plasma membranes with no interconnections, and are uninucleate. There is no surrounding ovary or oviduct. At hatching, two cells in each gonad are identifiable as parthenogenic eggs. The enlarged nucleolus of the most mature egg has already attained the morphology that persists throughout vitellogenesis, with intertwined granular and fibrillar threads. Less mature eggs have earlier stages of nucleolar development, and lack indications of meiotic events. Parthenogenic eggs enter vitellogenesis singly, with formation of RER and active Golgi complexes, and the accumulation of lipid, yolk, and various granules. The shell is formed in situ, whereas the spines elongate after egg deposition. Most animals produce four parthenogenic eggs, which undergo immediate development (tachyblastic eggs). Resting (opsiblastic) eggs are rare in isolation culture. Both types of eggs are produced only prior to the formation of sperm and primary oocytes. The absence of synaptonemal complexes, which would indicate synapsis of homologous chromosomes in prophase of meiosis I, implies that parthenogenesis is by apomixis in L. squammata.     

A histological and ultrastructural investigation of the female reproductive system of the water snake (Erythrolamprus miliaris): Oviductal cycle and sperm storage

We studied the structural and cellular organisation of the oviduct of Erythrolamprus miliaris including its morphological variation during the reproductive cycle using light microscopy, scanning electron microscopy and transmission electron microscopy. Four anatomically distinct regions compose the oviduct of E. miliaris including the anterior and posterior infundibulum, glandular uterus, non-glandular uterus and pouch. The cells of the oviductal epithelium secrete material by apocrine and merocrine processes, which vary between the anatomical regions and according to each phase of the reproductive cycle. The infundibular epithelium secretes electron dense vacuoles, which suggests the production of lipids, whereas the epithelial secretion of the glandular uterus, non-glandular uterus and pouch creates lucent and slightly electron dense vacuoles, indicating the production of glycoproteins. The timing of mating, vitellogenesis and sperm storage directly influences the morphofunctional alterations in the oviducts of E. miliaris. Sperm storage occurs only in the infundibular receptacles with increased production of the neutral carbohydrates in the presence of male gametes. Sperm storage happens in vitellogenic, non-vitellogenic and pregnant females of E. miliaris. Thus, females may be able to produce multiple clutches at different seasons of the year regardless of mating during autumn.     

The oocyte of a new world marsupial, Monodelphis domestica: structure, formation, and function of the enveloping mucoid layer

Ovulated oocytes of the gray short-tailed opossum Monodelphis domestica are surrounded by a thin zona pellucida and are devoid of a cumulus oophorus. In the ampulla of the oviduct, oocytes acquire a thick mucoid layer composed of concentrically arranged fibrillar material. Exocytosis by the secretory cells of the oviductal epithelium occurs in the region of the oviduct adjacent to the egg. This suggests that the oocyte-zona-mucus layer complex may influence the oviductal epithelium to secrete. During secretion, fibrillar contents of the secretion granules appear to be transformed into membranous material which presumably becomes fibrillar again as it is incorporated into the forming mucoid layer. Spermatozoa (which are known to pair in the cauda epididymis) are found in pairs and with intact acrosomes in the mucoid layer of fertilized eggs. This suggests that spermatozoa of Mondelphis remain paired until they reach the zona pellucida and that the acrosome functions in zona binding and/or penetration.     

An ultrastructural and histochemical study of oogenesis in the trichostrongylid nematode Heligmosomoides polygyrus

Oogenesis in trichostrongylids has been examined for the first time in a light and electron microscopic investigation of Heligmosomoides polygyrus. The female reproductive tract is a single straight tube containing small oogonia (6 micron in diameter), which are arranged in a rosette pattern around a central rachis at the anterior end of the tract. Developing oocytes separate from the rachis and pass posteriorly in single file down the growth zone. Oocytes increase rapidly in volume due to the accumulation of cytoplasmic inclusion granules. These granules are of 3 types. Type 1 granules are amorphous and probably consist primarily of lipoprotein. Type 2 granules are large lipid inclusions and type 3 granules are electron-dense lipoprotein yolk bodies, which are probably used for energy reserves in the developing embryo. Histochemical studies show a more intense reaction for DNA in the nuclei of oogonia than in the nuclei of oocytes. There is a strong reaction for RNA in the nucleoli and in the cytoplasm of oogonia and oocytes. Ultrastructural studies indicate that this RNA is probably in the form of rRNA in the abundant ribosomes. Mature oocytes are cylindrical (60 X 70 micron), have a distinct nucleus with nuclear pores, and the cytoplasm is filled with inclusion granules and ribosomes but contains only small amounts of glycogen. Prior to fertilization the plasma membrane of oocytes acquires a flocculent coat. These oocytes contain 6 distinct bivalent chromosomes in diakinesis. Thus the major changes that occur in developing germ cells are 2-fold: nuclear changes that prepare the chromosomes for fertilization by initiating reduction division, and cytoplasmic changes that involve the synthesis and storage of inclusion granules.     

Ultrastructural studies of early stages of oogenesis in a trichuroid nematode,Trichuris muris

Oogenesis within the hologonic ovary of the trichuroid nematode, Trichuris muris, was observed by light and electron microscopy. Early germinal stages in the form of oogonia and young primary oocytes were characterised by a high nuclear-cytoplasmic ratio, numerous ribosomes and several mitochondrial clusters. Previtellogenic primary oocytes contained a prominent nucleus with a nuclear envelope punctuated by pores. They also contained increased amounts of granular endoplasmic reticulum (GER), often arranged as annulate lamellae, several Golgi complexes and limited amounts of lipid. The appearance of three types of cytoplasmic inclusion, in the form of lipid, dense yolk granules and reticulate granules, indicated the onset of vitellogenesis. At this stage of oogenesis, all three types were distributed throughout the ooplasm. The possible role of the granules is discussed. During passage along the oviduct the oocyte was coated by an additional unit membrane and associated fibrillar layer external to the oolemma. It is suggested that this may be synthesised by the oocyte.     

Oviductal morphology in relation to hormonal levels in the snapping turtle, Chelydra serpentina

Microscopic and in situ visual observations were used to relate circulating hormone levels to morphological changes in the oviduct of the snapping turtle Chelydra serpentina throughout the ovarian cycle. Increase in levels of progesterone (P), estradiol (E2) and testosterone (T) levels coincide with an increase in number and growth of endometrial glands, luminal epithelial cells and secretory droplets throughout the oviduct. Testosterone and estradiol levels rose significantly (P < 0.05) after the May-June period and remained high throughout the rest of the summer. Progesterone levels remained stable throughout the summer, with a brief decline in July due to luteolysis. Hormonal values declined significantly (P < 0.001) at the end of the ovarian cycle in the fall. In situ visual observation of fresh oviducts at different stages of gravidity in recently ovulated turtles revealed that proteinaceous like components from the endometrial glands were released into the lumen to form fibers. The morphological features of the oviduct remained active throughout the summer months even though the snapping turtle is a monoclutch species which deposits all the eggs in late-May to mid-June. The high steroid levels correlate with and may be responsible for the secretory activity present throughout the summer and their decline correlates with change to low secretory activity in the fall. Calcium deposition accompanied by morphological changes in luminal cells are suggestive of secretory activity. In the egg-bearing turtles, uterine Ca2+ concentrations measured by flame atomic absorption spectrophotometry revealed significantly higher Ca2+ concentrations (P < 0.001) in eggs with soft shell than eggs without shell. There was a significant increase in calcium granules and proteinaceous fibers in luminal surface of the uterus during the period of eggshelling. This supports the fact that in the snapping turtle like in other reptiles, eggshelling process occurs in the uterus.     

Morphology of the ovaries of Sphaerodema (Diplonychus) rusticum (Heteroptera,Belostomatidae)

The female reproductive system of Sphaerodema rusticum consists of a pair of ovaries, two lateral oviducts, a median common oviduct, and a median spermatheca. Accessory glands are absent. Each ovary has five free ovarioles branching from the oviduct. Each ovariole consists of a terminal filament, germarium, vitellarium, brown mass, and an exceptionally long pedicel. The terminal filament consists of a central core, interstitial cells, and an outer sheath. In the germarium, which consists of trophic and prefollicular regions, the trophic region or nurse cell chamber is divided into four histologically differentiated zones, distinguished as zones I–IV. Nutritive cords, originating from the posterior end of the trophic core in zone IV extend centrally and join the developing oocytes in the prefollicular chamber and the vitellarium. The compact prefollicular tissue at the base of the trophic core gives rise to prefollicular cells which, after encircling the young oocytes, become modified into follicular epithelial cells, the interfollicular plug, and epithelial plug. The young oocytes descend into the vitellarium and gradually develop into mature oocytes. A compound corpus luteum is observed simultaneously in all the ovarioles of both ovaries after ovulation. Below the epithelial plug there is an accumulation of material, the “brown mass,” which develops cyclically in correlation with the ovulation cycle. Each pedicel stores five mature chorionated eggs ready for oviposition. The epithelium of the anterior region of the pedicel secretes a PAS-positive material. General morphology and histology of the subdivisions of the ovarioles are described.     

Morphology of female reproductive system of Mediterranean flatheaded peachborer,Capnodis tenebrionis (Linnaeus, 1761) (Coleoptera: Buprestidae)

Capnodis tenebrionis causes damage in many species of Rosaceae. The present study investigates on the morphology of the female reproductive system of C. tenebrionis. The female reproductive system of C. tenebrionis has a pair of ovaries, lateral oviducts, a common oviduct, spermatheca, and bursa copulatrix. Each ovary in C. tenebrionis consists of approximately 24 telotrophic meroistic type ovarioles. The ovarioles of C. tenebrionis have four regions (terminal filament, tropharium, vitellarium, and pedicel). Tropharium have trophocytes, young oocytes, and prefollicular cells. Vitellarium consists of previtellogenic, vitellogenic, and choriogenic oocytes. Previtellogenic oocyte is surrounded by cylindrical epithelial cells. Its ooplasm is homogeneous and basophilic. In vitellogenic oocyte, there are intercellular spaces between monolayered follicle cells. Its ooplasm has yolk granules and lipid droplets. Choriogenic oocyte are surrounded by chorion and single-layered cylindrical cells. There are yolk granules and lipid droplets in its ooplasm which is asidophilic. In C. tenebrionis female, spermatheca and bursa copulatrix wall is surrounded by thin cuticular intima, monolayer epithelial, glandular cells, and muscle layer. Spermatheca lumen contains a large number of spermatozoa. Bursa copulatrix lumen is filled with secretory material. This study may be useful in terms of the morphology of mature female reproductive organs of Buprestidae and other coleopteran species.     

Detection of nascent and/or mature forms of oviductin in the female reproductive tract and post-ovulatory oocytes by use of a polyclonal antibody against recombinant hamster oviductin.

Oviductins belong to a family of glycoproteins that have been suggested to play several roles during the early processes of reproduction. Recently, a polyclonal antibody was raised against recombinant hamster oviductin (rhaOv(m)). Here the anti-rhaOv(m) antibody was used to investigate the sites of localization of oviductin in the female golden hamster. In the hamster oviduct, immunolabeling was restricted to the content of the Golgi saccules and secretory granules of the non-ciliated oviduct cells. After its release into the lumen, oviductin becomes associated with the zona pellucida of post-ovulatory oocytes. In unfertilized oocytes, oviductin was also detected in membrane invaginations along the oolemma and in some vesicles within the ooplasm. Furthermore, oviductin was detected over the microvilli and within multivesicular bodies of uterine epithelial cells. Western blotting analysis revealed the presence of oviductin in the hamster oviduct but not in the uterus or ovary. In the oviduct, the anti-rhaOv(m) antibody detected a polydispersed band corresponding to native oviductin (160-350 kD) and several lower molecular weight bands (<100 kD) corresponding to nascent and partially glycosylated forms of oviductin. The anti-rhaOv(m) antibody provides an additional tool for investigation into the cytochemical and biochemical properties of different forms of hamster oviductin in the female reproductive tract.     

Morphological changes in the oviductal endometrium during the reproductive cycle of the tortoise,Gopherus polyphemus

The oviducts of 24 tortoises (Gopherus polyphemus) were examined using histological techniques and scanning electron microscopy to determine endometrial morphology. Measurements of endometrial characteristics (epithelial cell height, cilia length, thickness of endometrial glandular layer, and glandular diameter) in the uterus and tube (tuba uterina) were obtained to determine changes during the reproductive cycle. Epithelial cell height increases in both the uterus and the tube during vitellogenesis and remains hypertrophied during gravidity. Cilia length increases in the uterus during late vitellogenesis and gravidity, but the length of tubal cilia does not change during the reproductive cycle. The ratio of secretory to ciliated epithelial cells in the oviduct increases from quiescence to gravidity. The thickness of the glandular endometrial layer increases in both the uterus and tube during vitellogenesis. In the uterus, the glandular layer decreases in thickness during gravidity. The diameter of the uterine glands increases throughout vitellogenesis and gravidity; however, following ovulation glandular cells become depleted of secretory granules and cell height diminishes. The diameter of the tubal glands is unchanged during the reproductive cycle. Oviductal hypertrophy during vitellogenesis coincides with elevated circulating estradiol, whereas during gravidity progesterone concentrations peak (Taylor, '82, PhD Dissertation, University of Florida, Gainesville) and may induce secretion of albumen and eggshell components.     

Oviductal structure in a viviparous New Zealand gecko,Hoplodactylus maculatus

Oviductal structure is described in New Zealand's common gecko, Hoplodactylus maculatus, over four reproductive stages (early/mid-vitellogenesis, late vitellogenesis, early pregnancy, late pregnancy), using light, scanning electron, and transmission electron microscopy. Five regions of the oviduct are recognized: infundibulum, uterine tube, isthmus, uterus, and vagina. Up to three cell types make up the luminal epithelium of the oviduct: ciliated, nonciliated, and bleb cells. The function of bleb cells (seen in the infundibulum only) is unknown, but observation of these cells using transmission electron microscopy suggests that they are involved in secretory activity. Mucosal glands in the uterine tube possess large numbers of secretory granules of varying electron densities. Additionally, these glands appear to function as sperm storage tubules. Numerous sperm are seen in the glands during late vitellogenesis and early pregnancy. Very few uterine mucosal (shell) glands are seen during vitellogenesis, which is consistent with the observation that only a fine shell membrane covers the egg during early pregnancy. By late pregnancy, extraembryonic membranes lie adjacent to the uterus allowing the formation of the omphalo- and chorioallantoic placentas. Maximum cell height in the luminal epithelium is seen during vitellogenesis. The maximum percentage of ciliated cells making up the epithelial layer is seen during pregnancy. The low number of uterine mucosal glands seen in H. maculatus is a feature typical of other viviparous reptiles described, despite independent evolutions of viviparity. Although oviductal structure has been described in the literature for various reptiles, several ultrastructural features seen in this study highlight the lack of detailed understanding of this tissue. J. Morphol. 234:51-68, 1997. © 1997 Wiley-Liss, Inc.     

The ultrastructure of germinal beds in the ovary of Gerrhonotus coeruleus (Reptilia: Anguidae)

A study of ovarian structure in adult Alligator Lizards (Gerrhonotus coeruleus) was conducted by light microscopy and transmission electron microscopy. Particular attention was directed to characterizing the ultrastructure of germ-line cells, prior to follicle formation. General ovarian structure in this lizard is similar to that of other lizards. The paired organs are hollow, thin-walled sacs containing follicles in roughly 3 to 4 size classes. Ovarian germinal tissue consists of oogonia (diploid cells which divide mitotically) and oocytes (meiotic cells), intermixed with ovarian surface epithelial cells. Germ cells reside in two dorsal patches of epithelium per ovary (germinal beds), as is common in lizards. Oogonia in interphase show a highly dispersed chromatin pattern. Within oogonia cytoplasm, Golgi complexes are scarce, rough endoplasmic reticulum is absent, and lipid droplets are rare. Ribosomes are scattered in small clusters. Small, round vesicles are common in all oogonia; glycogen-like granules are present in some. Mitochondria form a juxtanuclear mass within which groups of several mitochondria surround a dense granule. “Nuage” granules also are found unassociated with mitochondria. Oocytes are present in stages of meiotic prophase up to diplotene. Synaptinemal complexes are seen in several (pachytene) cells. The cytoplasm of oocytes differs from that of oogonia in that mitochondria do not form groups, and nuage and glycogen are absent, whereas small round vesicles and large irregular vesicles are common. The ultrastructural similarities in germ cells of a reptile as compared to those of other vertebrates strengthens the notion that germ-line cells possess (or lack) qualities related to the undifferentiated state of these cells.     

Calcium ATPase expression in the oviducts of the skink, Lampropholis guichenoti

Lampropholis guichenoti is an oviparous lizard that lays eggs with a calcareous outer shell. We used immunofluorescence microscopy to describe the occurrence and distribution of Ca2+ ATPase pumps in the uterus of L. guichenoti at different stages of the reproductive and egg-shelling cycles. Ca2+ ATPase pumps were not demonstrated by immunofluorescent techniques in any uterine tissue until egg-shelling had commenced and at least partly calcified eggs were in the uterus. During egg-shelling, Ca2+ ATPase pumps occur on the apical and baso-lateral surfaces of uterine epithelial cells, and those of associated shell glands in the stroma of the uterus. We conclude that Ca2+ ATPase pumps provide a major mechanism for deposition of the calcareous eggshell of L. guichenoti and that the pumps are up-regulated when required in the reproductive cycle. Furthermore, it is likely that specific calcium glands in the stroma of the uterus are involved in the rapid transport required for egg-shelling, but the differential contribution of luminal and glandular epithelial cells is not known.     

Immunohistochemical localization of taurine in the rat ovary, oviduct, and uterus.

The distribution of the amino acid taurine in the female reproductive organs has not been previously analyzed in detail. The aim of this study was to determine taurine localization in the rat ovary, oviduct, and uterus by immunohistochemical methods. Taurine was localized in the ovarian surface epithelium. The granulosa cells and oocytes of primordial follicles were immunonegative. In primary and antral follicles, taurine was found mainly in theca cells and oocytes, whereas the zona pellucida, antrum, and most granulosa cells were unstained. However, taurine immunoreactivity in theca cells and oocytes decreased during follicular atresia. During corpora lutea development, the number of immunopositive theca lutein cells increased as these cells invaded the granulosa-derived region. Therefore, most luteal cells from the mature corpora lutea were stained. In the regressing corpora lutea, however, taurine staining in luteal cells decreased. In the fimbriae, infundibulum, and uterotubal junction, taurine was localized in most epithelial cells. In the ampullar and isthmic segments, taurine was found in the cilia of most ciliated cells and in the apical cytoplasm of some non-ciliated cells. In the uterus, most epithelial cells were immunopositive during diestrus and metestrus, whereas most of them were immunonegative during estrus and proestrus. Moreover, taurine immunoreactivity in the oviduct and uterus decreased with pregnancy. (J Histochem Cytochem 49:1133-1142, 2001)