Secretory Vacuoles Research Articles

Observations on the Sexual Segment of the Kidney of Snakes with Emphasis on Ultrastructure in the Yellow‐Bellied Sea Snake, Pelamis platurus

The sexual segment of the kidney (SSK) is an accessory sex structure in male lizards and snakes (Squamata). We describe histology of the SSK in 12 species of snakes, including one from the basal Scolecophidia, Leptotyphlops dulcis, and from the more advanced Alethinophidia, species from the Acrochordidae (Acrochordus granulatus), Homalopsidae (Cerberus rynchops), Uropeltidae (Teretrurus sanguineus), and eight species from the Elapidae, including six species of sea snakes. We also describe the ultrastructure of the SSK of the sea snake, Pelamis platurus. The SSK of L. dulcis does not include the ureter but does include distal convoluted tubules (DCTs) and collecting ducts. In all other snakes examined, the SSK is limited to the DCTs and does not differ in histology by any consistent character. We found apparently mature individuals of several species with inactive SSKs. Hypertrophied SSKs give positive reactions for protein secretions but variable reactions for carbohydrates. Ultrastructure of the SSK of P. platurus reveals nuclei situated medially in the epithelium and mature electron dense secretory vacuoles in other areas of the cytoplasm. Product release is apocrine. Junctional complexes only occur at the luminal border, and intercellular canaliculi become widened and are open basally. No cytologically unique characters occur in the SSK of P. platurus. The ancestral condition of the SSK in squamates is the presence of simple columnar epithelium specialized for secretion of a protein + carbohydrate product that matures and is released seasonally.

Effects of low level testosterone on the corpus cavernosum cells in rats with diabetes mellitus-induced erectile dysfunction

Objective To investigate the changes of testosterone levels and the effect of low level testosterone on the corpus cavernosum tissue and its ultrastructure in rats with diabetes mellitus-induced erectile dysfunction.Methods Three-month-old male Wistar rats ( n =20) were divided into 2 groups:the contorl group (n =10) and the diabetes mellitus-induced erectile dysfunction group (n =10).Serum levels of testosterone were measured by radioimmunoassay and the percentage of corporal smooth muscle cells was detected by Masson staining.The ultrastructures of corporal smooth muscle cells were examined under the transmission electron microscopy.Results The serum levels of testosterone in the diabetes mellitus-induced erectile dysfunction group ( 17.445 ± 2.540) nmol/L were obviously lower than in the contorl group (338.457 ± 63.802) nmol/L,P ＜ 0.01.The percentage of corporal smooth muscle cells ( 19.890 ±1.957) ％ was higher in the control group than in the diabetes mellitus-induced erectile dysfunction group (5.640 ± 0.597)％,P ＜0.01.Ultrastructurally,in the smooth muscle cells of cavernous tissue,there were more Goigi bodies and secretory vacuoles,and the karyoplasmic ratio was higher in the diabetes mellitus-induced erectile dysfunction group than in the control group.Aslo the degeneration of mitochondria,the dilatation of endoplasmic reticulum and the decreases of glycogen particles and microfilaments could be observed.Conclusion The decline of testosterone levels may lead to the pathological changes of corpus caveruosum cells in rats with diabetes mellitus-induced erectile dysfunction. Key words: Testosterone; Erectile dysfunction; Diabetes mellitus; Ultrastructu

Morphology of Rathke's Glands in the Snapping Turtle, Chelydra serpentina, with Comments on the Presence of Multilaminar Lamellar Bodies in Turtles

I examined the histology and ultrastructure of Rathke’s glands in hatchling, juvenile, and adult snapping turtles (Chelydra serpentina). This species possesses four pairs of Rathke’s glands (i.e., one axillary and three inframarginals) that are embedded beneath marginal bones and are named primarily according to the anatomical location of their orifices. These integumentary glands are similar anatomically and ultrastructurally to one another. Each gland is comprised of a single, highly vascularized, secretory lobule, which is surrounded by a thick tunic of asymmetrically arranged, striated muscle. Two types of large secretory vacuoles characterize most of the holocrine cells produced by a relatively thin secretory epithelium. My results support previous studies that suggest that the chief secretory material of the mostly larger, dark-staining Type 1 secretory vacuole is a glycoprotein complex. The mostly translucent Type 2 secretory vacuole may contain osmiophilic granules that exhibit variously sized lamellar bodies, whose multilaminar structural design is reminiscent of an epidermal lipid delivery system in many vertebrates. The functional role of Rathke’s gland secretions in Chelydra serpentina and in other turtles remains unknown.

Expression and activation of the membrane-cytoskeleton protein ezrin during the normal endometrial cycle

To examine total ezrin expression (ezrin and phospho-ezrin) through the normal endometrial cycle and to correlate ezrin activation and localization with cytologic changes. Experimental laboratory study. University medical centers. Reproductive-age women. A total of 36 samples of normal early, mid-, and late proliferative- and secretory-phase endometrium were studied for immunoreactive total ezrin (ir-T-ezrin) and phospho-ezrin (ir-p-ezrin) expression by histology, immunohistochemistry, and Western blotting. Total ezrin and phospho-ezrin expressions through the normal endometrial cycle. Throughout the cycle ir-T-ezrin is present in the epithelium. The intensity and localization of both ir-ezrin and ir-p-ezrin vary greatly throughout the cycle. The main findings include the following: lateral localization of ir-ezrin/ir-p-ezrin in association with membrane specializations; dense staining around secretory vacuoles (secretory phase); dense staining of the apical surfaces, including microvilli and pinopodes of epithelial cells, especially during the mid- to late secretory phases; and the presence of ezrin in the glandular secretions. Immunoreactive total ezrin and ir-p-ezrin were not expressed by stromal fibroblasts. Ezrin is a prominent protein in the cycling endometrium. The most striking findings were the gravitation of ir-ezrin/ir-p-ezrin to the periphery of secretory vacuoles, localization on apical surfaces of the luminal epithelium, dense ezrin staining in secretory-phase epithelial cell plumes, and the presence of ir-ezrin/ir-p-ezrin in secretory-phase luminal secretions. These findings may have functional implications, especially for implantation biology.

Observations on the anterior testicular ducts in snakes with emphasis on sea snakes and ultrastructure in the yellow‐bellied sea snake, Pelamis platurus

The anterior testicular ducts of squamates transport sperm from the seminiferous tubules to the ductus deferens. These ducts consist of the rete testis, ductuli efferentes, and ductus epididymis. Many histological and a few ultrastructural studies of the squamate reproductive tract exist, but none concern the Hydrophiidae, the sea snakes and sea kraits. In this study, we describe the anterior testicular ducts of six species of hydrophiid snakes as well as representatives from the Elapidae, Homolapsidae, Leptotyphlopidae, and Uropeltidae. In addition, we examine the ultrastructure of these ducts in the yellow-bellied Sea Snake, Pelamis platurus, only the third such study on snakes. The anterior testicular ducts are similar in histology in all species examined. The rete testis is simple squamous or cuboidal epithelium and transports sperm from the seminiferous tubules to the ductuli efferentes in the extratesticular epididymal sheath. The ductuli efferentes are branched, convoluted tubules composed of simple cuboidal, ciliated epithelium, and many species possess periodic acid-Schiff+ granules in the cytoplasm. The ductus epididymis at the light microscopy level appears composed of pseudostratified columnar epithelium. At the ultrastructural level, the rete testis and ductuli efferentes of P. platurus possess numerous small coated vesicles and lack secretory vacuoles. Apocrine blebs in the ductuli efferentes, however, indicate secretory activity, possibly by a constitutive pathway. Ultrastructure reveals three types of cells in the ductus epididymis of P. platurus: columnar principal cells, squamous basal cells, and mitochondria-rich apical cells. This is the first report of apical cells in a snake. In addition, occasional principal cells possess a single cilium, which has not been reported in reptiles previously but is known in some birds. Finally, the ductus epididymis of P. platurus differs from other snakes that have been studied in possession of apical, biphasic secretory vacuoles. All of the proximal ducts are characterized by widening of adjacent plasma membranes into wide intercellular spaces, especially between the principal cells of the ductus epididymis. Our results contribute to a larger, collaborative study of the evolution of the squamate reproductive tract and to the potential for utilizing cellular characters in future phylogenetic inferences.

Evidence of an Alternative Route of Cellobiase Secretion in the Presence of Brefeldin A in the Filamentous Fungus Termitomyces clypeatus

Secretion of cellobiase occurred in a brefeldin A (BFA) uninhibited manner in the filamentous fungus Termitomyces clypeatus. Fluorescence confocal microscopy revealed that application of the drug at a concentration of 50 microgram/ml caused arrest of Spitzenkorper assembly at the hyphal tip. This resulted in greater than 30% inhibition of total protein secretion in the culture medium. However, the cellobiase titer increased by 17%, and an additional 13% was localized in the vacuolar fraction en route secretion. The secretory vacuoles formed in the presence of the drug were also found to be bigger (68 nm) than those in the control cultures (40 nm). The enzyme secreted in the presence and absence of BFA revealed a single activity band in both cases in native PAGE and had similar molecular masses (approx. 120 kDa) in SDS-PAGE. The BFA enzyme retained 72% of native glycosylation. It also exhibited a higher stability and retained 98% activity at 50°C, 93.3% activity at pH 9, 63.64% activity in the presence of 1M guanidium hydrochloride, and 50% activity at a glucose concentration of 10 mg/ml in comparison to 68% activity, 75% activity, 36% activity, and 19% activity for the control enzyme, respectively. The observations collectively aimed at the operation of an alternative secretory pathway, distinct from the target of brefeldin A, which bypassed the Golgi apparatus, but still was able to deliver the cargo to the vacuoles for secretion. This can be utilized in selectively enhancing the yield and stability of glycosidases for a successful industrial recipe.

Acid phosphatase in blood smears of Phrynops geoffroanus (Testudines: Chelidae)

Acid phosphatases belong to the hydrolases class of enzymes; they act on organic esters, releasing phosphate ions in acidic conditions. These enzymes are found in lysosomes and secretory vacuoles. They are important for tissue autolysis and proliferation and differentiation and cell transformation processes, but also indicate possible tumors. Deficiency may limit leukocytes, resulting in recurrent infections.(1) Acid phosphatase staining was performed in blood smears of Phrynops geoffroanus using the lead phosphate method,(2) with eosinophils being strongly stained (Figure 1). In human blood samples this cytochemical stains the neutrophils. In chelonians, there is a low number of neutrophils and a high number of circulating eosinophils which respond to parasitic infections.(3) Cytoplasmic staining suggests that eosinophils are rich in lysosomes which is probably related to their mobilization as defense cells. Figure 1 Acid phosphatase technique in blood smears of Phrynops geoffroanus. The image on the left shows detection of the enzyme in eosinophils and on the right is the control reaction performed on a sample from the same individual. The arrows identify eosinophils ...

An investigation of ECM secreting structures in the gastrula of the starfish Pisaster ochraceus

To highlight the diversity of extracellular embryonic matrix (ECM) secreting structures in the gastrulae of the starfish Pisaster ochraceus the localization of antibody generated to hyaline layer, was studied. It was shown that hyaline layer epitope takes place in the cortical granules. Moreover, this material was revealed in secretory vacuoles and secretory vesicles which are situated in the apical parts of ectoderm cells. Besides, the same molecules were found in the yolk granules having loosened content. It seems likely that in P. ochraceus the ECM is secreted by four types of secretory structures.

The tarsal gland of ixodid ticks Ixodes persulcatus and Ixodes ricinus (Mesostigmata, Ixodidae)

A complicated multicellular gland is situated in all the leg tarsi, occupying from one third to half the segment. The glandular cells form a single-layer sack; the inner surface of the gland cavity is covered with the multi-layer membrane. Cuticular rods (“sinews”) of muscles moving the claw pass inside the gland cavity. The glandular cells are characterized by the presence of numerous microvilli on their apical surfaces and by the presence of secretory vacuoles. The basal part of each secretory cell is characterized by accumulations of lipid vacuoles and glycogen granules. Problems concerning the possible role of tarsal gland in the production of the trace pheromone are discussed.

Does administration of non-steroidal anti-inflammatory drug determine morphological changes in adrenal cortex: ultrastructural studies.

Rofecoxib (Vioxx© made by Merck Sharp & Dohme, the USA) is a non-steroidal anti-inflammatory drug which belongs to the group of selective inhibitors of cyclooxygenasis-2, i.e., coxibs. Rofecoxib was first registered in the USA, in May 1999. Since then the drug was received by millions of patients. Drugs of this group were expected to exhibit increased therapeutic action. Additionally, there were expectations concerning possibilities of their application, at least as auxiliary drugs, in neoplastic therpy due to intensifying of apoptosis. In connection with the withdrawal of Vioxx© (rofecoxib) from pharmaceutical market, attempts were made to conduct electron-microscopic evaluation of cortical part of the adrenal gland in preparations obtained from animals under influence of the drug. Every morning animals from the experimental group (15 rats) received rofecoxib (suspension in physiological saline)—non-steroidal anti-inflammatory drug (Vioxx©, Merck Sharp and Dohme, the USA), through an intragastric tube in the dose of 1.25 mg during 8 weeks. In the evaluated material, there was found a greater number of secretory vacuoles and large, containing cholesterol and other lipids as well as generated glucocorticoids, lipid drops in cytoplasm containing prominent endoplasmic reticulum. There were also found cells with cytoplasm of smaller density—especially in apical and basal parts of cells. Mitochondria occasionally demonstrated features of delicate swelling. The observed changes, which occurred on cellular level with application of large doses of the drug, result from mobilization of adaptation mechanisms of the organism.

Histopathologic features of esophageal glands in the region of the gastroesophageal junction in Chinese patients with gastric cardiac cancer involving the esophagus

Esophageal glands (EGs) were implicated previously as a potential origin of carcinomas of the gastroesophageal junction (GEJ). The studies of histopathology on diseases in EGs, however, are scarce. In the present study, we systematically investigated EGs in 36 resection cases of gastric cardiac carcinomas involving the esophagus (GCE) in Chinese patients. All cases showed chronic inflammation in EGs and 14 (39%) with Helicobacter pylori infection. Hyperplasia, atrophy, and dysplasia were common in EGs and observed in 21 (58%), 14 (39%), and 28 (78%) cases, respectively. These changes were associated with various types of metaplasia, including intestinal (6, 17%), oncocytic (26, 72%), pancreatic acinar (11, 30%), and squamoid metaplasia (8, 22%). Oncocytic metaplasia was patchy, frequently replaced the entire lobule with dysplastic features. Pancreatic acinar metaplasia was present in superficial EGs as small acinar patches. Squamoid metaplasia was limited to the EG drainage ductile epithelium without keratin pearls or intercellular bridges; however, cytoplasmic vesicles and secretory vacuoles were common, suggesting dual differentiation. Dysplastic EGs featured architectural disarray with fused acini, cribriforming, abortive growth, and nuclear hyperchromasia, enlargement, and overlapping. The results demonstrate a spectrum of histopathologic changes in EGs and ductile epithelium, which is similar to those observed in GCE in Chinese patients.

Stress and reproduction inBoiga irregulariswith notes on the ultrastructure of the sexual segment of the kidney in squamates

The reproductive tract of wild-caught male Boiga irregularis (Merrem, 1802) (Brown Treesnake) and the changes that result in these tissues from captivity are described. Wild-caught snakes were compared with snakes kept in captivity and sacrificed at approximately 10, 30, 50, and 60+ days. Snakes sacrificed after 10 days in captivity showed no differences in histological appearance or epithelial height in either the testis or sexual segment of the kidney (SSK) compared with wild snakes. Normal spermatogenic stages and SSK ultrastructure were observed in the testes and kidney from wild specimens and captive specimens after 10 days. In terms of the SSK, large electron-dense secretory vacuoles occupied the apices of the epithelial cells, while a basal nucleus, rough endoplasmic reticulum, and Golgi bodies filled the bases of these cells. All SSK cells were actively secretory in a mode that could most accurately be termed apocrine. At time of secretion, released vacuoles become diffuse and the apical membrane ruptures, spilling the SSK contents into the distal nephron lumen. Between 10 and 30 days in captivity, spermatogenesis and secretion in the SSK ceased and the epithelial height of both tissues decreased. At approximately 60 days, testicular epithelial height increased and spermatogenic activity was reestablished. The SSK, however, remained regressed at 60 days.

Histological and ultrastructural characterization of the alimentary system of solifuges (Arachnida, Solifugae)

Solifuges are voracious and fast predators. Once having captured a prey item, mostly small arthropods or even small vertebrates, they start feeding on their prey by constant chewing movements with their huge chelicerae. At the same time, they squeeze out the soft tissue that passes the anterior lattice-like part of the mouthparts. The digestion of the food takes place in the midgut, which is anatomically highly complex. It consists of the midgut tube from which numerous prosomal and opisthosomal diverticula and tubular lateral branches arise. The dimorphic epithelium of the midgut tube and the diverticula is constituted of digestive and secretory cells. The digestive cells are characterized by an apical tubulus system and contain nutritional vacuoles, lipids, spherites, and glycogen. Secretory cells contain a huge amount of rough endoplasmic reticulum and secretory vacuoles. The lateral branches are ultrastructurally similar to Malpighian tubules and are likely involved in excretion. In contrast to the midgut, the epithelium of the hindgut consists of only one type of cell overlain by a thin cuticle. Digested residuals are stored in the hindgut until defecation.

Breast secretory carcinoma: a clinicopathologic study of four cases

Objective: To explore the clinicopathologic features of secretory carcinoma of breast (SCB). Methods: Four cases of SCB were analyzed by light microscopy, histochemistry, immunohistochemistry and electron microscopy. The clinical data were also analyzed. Special staining of periodic acid-Schiff reaction with diastase pretreatment, immunohistochemical staining of ER, PR, HER-2, p53, MIB-1, S-100, p63, CK8/18 and EMA by En Vision method were performed. Results: Solid, cribriform, tubular, or papillary architecture may be seen. Tumor forms cystic spaces filled with abundant pale pink secretory material, positive with diastase resistant periodic acid-Schiff (PAS-DR) stains. Tumor cells were small with bland nuclei and abundant pale, eosinophilic cytoplasm, rare mitotic activity and necrosis. Immunohistochemically, tumor cells were positive for CK8/18, EMA, negative for S-100, p63 and variable partially positive for p53, ER, PR, HER-2 and MIB-1. Under electron microscopy, the tumor cells possessed numerous membrane-bound secretory vacuoles in cytoplasm lined by microvilli. Con- clusion: SCB is a rare, low-malignant neoplasm. SCB have pathology, clinical picture, treatment, follow-up, immunohisto- chemical and genetic features that distinguish them from invasive ductal carcinomas of the usual type.

An overview of the pale and clear cells of the nipple epidermis.

The stratified squamous epithelium of the nipple-areola complex may contain pale or clear cells including: Paget's disease cells (PDCs), Toker cells (TCs), and so-called clear cells (CCs). Paget's disease is an uncommon presentation of breast carcinoma. PDCs are large, atypical, have abundant, pale-staining cytoplasm that may contain mucin secretion vacuoles and bulky heterochromatic nuclei. They are commonly concentrated along the basal layer and stain for EMA, CAM5.2, cytokeratin 7, and HER2/neu oncoprotein. TCs are bland cells with roundish and scant chromatin nuclei. They are found incidentally and are reactive for EMA, CAM5.2, and cytokeratin 7, but show negativity for HER2/neu oncoprotein. So-called CCs show varied morphology, are found incidentally, and have been variably interpreted by different authors. The majority of cells that have been called epidermal CCs fit the features of pagetoid dyskeratosis. These cells are reactive for high molecular weight cytokeratin. Other CCs showing signet-ring morphology present negativity for mucins and correspond to a fixation artefact.

The central nervous system of sea cucumbers (Echinodermata: Holothuroidea) shows positive immunostaining for a chordate glial secretion.

BackgroundEchinoderms and chordates belong to the same monophyletic taxon, the Deuterostomia. In spite of significant differences in body plan organization, the two phyla may share more common traits than was thought previously. Of particular interest are the common features in the organization of the central nervous system. The present study employs two polyclonal antisera raised against bovine Reissner's substance (RS), a secretory product produced by glial cells of the subcomissural organ, to study RS-like immunoreactivity in the central nervous system of sea cucumbers.ResultsIn the ectoneural division of the nervous system, both antisera recognize the content of secretory vacuoles in the apical cytoplasm of the radial glia-like cells of the neuroepithelium and in the flattened glial cells of the non-neural epineural roof epithelium. The secreted immunopositive material seems to form a thin layer covering the cell apices. There is no accumulation of the immunoreactive material on the apical surface of the hyponeural neuroepithelium or the hyponeural roof epithelium. Besides labelling the supporting cells and flattened glial cells of the epineural roof epithelium, both anti-RS antisera reveal a previously unknown putative glial cell type within the neural parenchyma of the holothurian nervous system.ConclusionOur results show that: a) the glial cells of the holothurian tubular nervous system produce a material similar to Reissner's substance known to be synthesized by secretory glial cells in all chordates studied so far; b) the nervous system of sea cucumbers shows a previously unrealized complexity of glial organization. Our findings also provide significant clues for interpretation of the evolution of the nervous system in the Deuterostomia. It is suggested that echinoderms and chordates might have inherited the RS-producing radial glial cell type from the central nervous system of their common ancestor, i.e., the last common ancestor of all the Deuterostomia.

Sperm aggregations in female Agkistrodon piscivorus (Reptilia:Squamata): A histological and ultrastructural investigation

Upon copulation in female Agkistrodon piscivorus, sperm migrate up the oviduct to sperm storage tubules (SSTs) in the posterior infundibulum. The epithelium of the SSTs is composed of ciliated and secretory cells and differs ultrastructurally from that of the epithelium lining the lumen of the posterior infundibulum. Sperm pass through an area composed primarily of ciliated cells at the opening of each gland before aligning themselves in parallel arrays with their nuclei facing an area composed primarily of secretory cells at the base of the tubules. Sperm are also found embedded inter- and intracellularly in the SSTs. The secretory vacuoles in the SSTs become highly electron dense after the start of the fall mating season along with the synthesis of lipid droplets. Histochemical analysis reveals that the alteration in secretory material density is caused by the production of neutral carbohydrates. Some sperm remain in aggregates in the nonglandular section of the posterior uterus until the time of ovulation. However, ultrastructural evidence indicates these sperm degrade before ovulation. Therefore, sperm in posterior aggregates have no role in fertilization of ovulated ova. The data presented here support the hypothesis that infundibular sperm storage is the mode that snakes utilize to sequester viable sperm until ovulation.

Morphological and glycosylation changes associated with the endometrium and ectopic lesions in a baboon model of endometriosis

Endometriosis is one of the most common causes of infertility and pelvic pain. A baboon model has recently been developed whereby the intrapelvic injection of menstrual endometrium results in the induction of endometriotic lesions. We have used this model to investigate changes in ultrastructure and glycosylation of endometria from normal and diseased baboons. Endometriosis was induced in eight female baboons; endometrial tissue and endometriotic lesions were removed on days 9-11 post ovulation between 3 and 16 months of disease and compared with endometrium from 17 control animals, using electron microscopy and lectin histochemistry. Ultrastructurally, diseased endometrial glands showed abnormalities in secretory vacuoles and an intracellular accumulation of glycogen; in later stages of the disease, glands resembled those of the late secretory phase endometrium. The abnormalities were mirrored by changes in glycan expression. In early disease, there was an increased binding of lectin from Dolichos biflorus agglutinin (DBA) to fucosylated N-acetylglucosamine residues, whereas in later stages, this binding generally decreased in association with the appearance of a late secretory phenotype. Endometriosis is accompanied by progressive changes in the gland architecture and biochemistry resulting in dyssynchrony within the window of uterine receptivity, which may result in the reduced fertility associated with this disease.

Sperm aggregations in the spermatheca of the red back salamander (Plethodon cinereus)

AbstractThe spermatheca of Plethodon cinereus is a compound tubular gland that stores sperm from mating in early spring (March–April) to oviposition in summer (June–July). The seasonal variation of sperm storage in this species has previously been studied by light and transmission electron microscopy. In this paper, sperm aggregations, interaction of sperm with the spermathecal epithelium, and spermathecal secretions are studied using scanning electron microscopy. Within spermathecal tubules, relatively small groups of sperm are aligned along their entire lengths in parallel arrays. This pattern is similar to other plethdontids with complex spermathecae. Lumina of spermathecal tubules are filled with secretory material in April prior to the arrival of sperm, and after sperm appear, a coating of secretory material persists on the apices of the spermathecal epithelium. Sperm peripheral to the central luminal mass can become embedded in the secretory matrix or pushed deeper into the spermathecal epithelium. The spermathecal secretions may serve to attract and prolong the viability of sperm, but sperm that become enmeshed in the secretions or epithelium are phagocytized. Sperm and spermathecal secretions are largely absent after ovulation and in summer months, and new secretory vacuoles are formed in fall, although mating does not occur until spring.

Regeneration of the epithelial lining of the stomach after autotomy of a disk in the brittle star Amphipholis kochii (Lütken) (Echinodermata: Ophiuroidea)

The regeneration of the epithelial lining of the stomach of the brittle star Amphipholis kochii after autotomy of the aboral part of the disk was studied. It was shown that a part of the stomach epithelium remained after autotomy. Its cells participated in regeneration of the epithelium during restoration of the lost digestive system. There was a partial dedifferentiation of the epithelium cells of stomach, their migration and proliferation; cells of the stomach retained some specialized cytoplasmic structures, secretory vacuoles, and pinocytic vesicles. Migration of ectodermal cells of the esophagus in the damaged area was also recorded.