doi:10.1369/jhc.4A6540.2005
Volume 53 (10): 1203-1214, 2005 Copyright ©The Histochemical Society, Inc. Ultrastructural Studies and Na+,K+-ATPase Immunolocalization in the Antennal Urinary Glands of the Lobster Homarus gammarus (Crustacea, Decapoda)
Equipe Adaptation Ecophysiologique et Ontogenèse, Université Montpellier II, Montpellier, France (SK,GC,MC-D), and Faculty of Marine Sciences, University of Tarbiat Modarres, Tehran, Iran (SK) Correspondence to: Mireille Charmantier-Daures, Equipe Adaptation Ecophysiologique et Ontogenèse, UMR 5171 GPIA, Université Montpellier II, cc 092, 34095 Montpellier cedex 05, France. E-mail: charmantier.daures{at}univ-montp2.fr
Unlike in crustacean freshwater species, the structure and ultrastructure of the excretory antennal gland is poorly documented in marine species. The general organization and ultrastructure of the cells and the localization of Na+,K+-ATPase were examined in the antennal gland of the adult lobster Homarus gammarus. Each gland is composed of a centrally located coelomosac surrounded ventrally by a labyrinth divided into two parts (I and II) and dorsally by a voluminous bladder. There is no differentiated nephridal tubule between them. The labyrinth and bladder cells have in common a number of ultrastructural cytological features, including basal membrane infoldings associated with mitochondria, apical microvilli, and cytoplasmic extrusions, and a cytoplasm packed with numerous vacuoles, vesicles, lysosome-like bodies, and swollen mitochondria. Each type of cell also presents distinctive characters. Na+,K+-ATPase was detected through immunofluorescence in the basal part of the cells of the labyrinth and in the bladder cells with an increasing immunostaining from labyrinth I to the bladder. No immunoreactivity was detected in the coelomosac. The cells of the labyrinth and of the bladder present morphological and enzymatic features of ionocytes. The antennal glands of the lobster thus possess active ion exchanges capabilities. (J Histochem Cytochem 53:12031214, 2005)
Key Words: excretory organ osmoregulation fine structure immunolocalization Na+,K+-ATPase
IN DECAPODS CRUSTACEANS, three organs, the gut, the antennal glands and the branchial chambers, are involved in excretory and ion-regulatory functions. The urinary system radically differs from the other two in that its input fluid is entirely internal (i.e., hemolymph), whereas the branchial chambers and, to a lesser extent, the gut can directly interact with both the internal and external media. The excretory system of decapods consists of paired antennal glands, which rest in the basal antennal segment of the cephalothorax. The hemolymph supply of the antennal glands originates mainly from the antennal and the sternal arteries. As with the vertebrate kidney, these organs participate in maintaining the volume of the extracellular fluid and regulating its concentration in ions, nutrients, and other solutes (Mantel and Farmer 1983
From an osmoregulatory point of view, the juveniles and adults of homarid lobsters are osmoconformers in seawater and are slight hyperregulators in dilute media (Dall 1970
Because of the active implication of the antennal glands in osmoregulation of freshwater decapods through the production of dilute urine, their structure has been more intensively studied in these species than in closely related marine species. This is particularly true in the Astacidea, in which the structure of the antennal glands has been described in several species of crayfish (review in Khodabandeh et al. 2005a
Although several physiological studies have been conducted on the antennal glands of homarid lobsters, no structural information is available on them except for the pioneering observations of Waite (1899) The aim of the present study was to: (a) describe the structure and ultrastructure of the different parts of the antennal glands in the adult European lobster H. gammarus and (b) locate potentially ion-transporting cells and localize Na+,K+-ATPase. Investigations were conducted through light and electron microscopy and through immunofluorescence for the enzyme detection.
Animals Adult H. gammarus caught off the coast of Brittany and obtained from a shellfish retailer (Les Viviers de Roscoff, Roscoff, France) were maintained at the Montpellier laboratory in individual compartments containing aerated and recirculated (Eheim Systems) natural seawater (35.0 ± 1.3%, 20 ± 1C) and were fed mussels three times per week. The photoperiod was held constant at 12L:12D.
Histology
Electron Microscopy For scanning electron microscopy, samples were placed in cold 4% glutaraldehyde in 0.1 M phosphate buffer, pH 7.4, containing 5% sucrose. After an initial 1 hr fixation, followed by rinsing in 0.1 M phosphate buffer containing 5% sucrose, the samples were postfixed for 1 hr in 2% osmium tetroxide in 0.1 M phosphate buffer, pH 7.4, containing 5% sucrose.
Immunocytochemistry
After 24 hr in Bouin's fixator and embedment in paraplast, sections of 35 µm were cut on a Leitz Wetzlar microtome and collected on poly-L-lysinecoated slides. The immunocytochemistry procedure has been previously described (Lignot et al. 2001
General Organization In adult H. gammarus, the antennal gland as seen from above is triangular in shape and flattened (Figure 1A). The bottom of the hilus is close to the center of the gland (Figure 1A). The antennal gland presents three lobes, two external and internal anterior lobes and one posterior main lobe (Figure 1A). It lies on the ventral floor of the cephalothorax, but part of the anterior lobes extends into the basis of the antenna. Each gland is composed of three regions: the coelomosac, the labyrinth, and the bladder linked by a short duct to the urinary pore. The coelomosac is located on the dorsal part of the labyrinth and it possesses a central cavity (Figures 1B and 1C). The dorsal face of the coelomosac is in close contact with the ventral wall of the overlying bladder (Figure 1C). The coelomosac region displays regularly organized cavities limited by single layer of cells (Figure 1E and Figure 2A). The cells form many complete and incomplete septa in the wall of the coelomosac, which are more abundant on the ventral than on the dorsal wall (Figures 1D and 1E; Figure 2A). Each septum is constituted by a folded epithelium embracing a sheet of connective tissue between its two layers (Figure 1E). The connective tissue contains hemolymph vessels. The opening of the coelomosac to the underlying labyrinth is located in the main lobe of the gland immediately behind the hilus (Figure 1B). This connection is the only location where the cells of the coelomosac and of the labyrinth come into contact.
The labyrinth constitutes the greater bulk of the gland (Figures 1B and 1C). Its ventral part is covered by a connective tissue (Figures 1C and 1D). This tissue is highly vascular, mainly formed by the walls of hemolymph vessels and hemolymph spaces (not shown). The labyrinth (Figures 1B1D) consists of a very complicated spongy-like tissue. The space between the epithelial lining is occupied by a connective tissue (Figures 1C and 1D). The dorsal face of the labyrinth is covered by the coelomosac, except in the border areas (Figure 1C). In this region, two subregions have been observed, labyrinth I and II. Labyrinth I immediately follows the coelomosac and forms the main part of the labyrinth. Labyrinth II is present only in the lateral border of the labyrinth where it connects with the bladder (Figure 1C). The lumen of this subregion is considerably reduced compared with the lumen of labyrinth I (not shown). The bladder (Figure 1C) is a large reservoir, firmly attached to the dorsal face of the gland. Between the basal membrane of the epithelium of the bladder (ventral wall) and the coelomosac lies a rich plexus of vessels. The bladder (Figures 1F and 1G) is lined by a single layer of epithelial cells covered by conjunctive tissue, and a system of hemolymph vessels is present in between. The thickness of the conjunctive layer is more variable than that of the epithelial layer (Figure 1G). It is composed of flattened cells with a centrally located nucleus, organized into one to several cellular layers.
Ultrastructure In all parts of the labyrinth and of the bladder, the cells present several common features, including apical microvilli, apical cytoplasmic extrusions (Figure 2D; Figure 3A; Figures 4A and 4B; Figures 5A and 5B), and basal membrane infoldings associated with mitochondria (Figure 2A; Figure 3C; Figure 4C; Figure 5B). The arrangement of apical microvilli is usually disturbed by the formation of cytoplasmic extrusions that become detached and pass into the lumen (Figure 2D; Figure 3A; Figure 4A; Figure 5A). The cytoplasm contains lysosome-like bodies, abundant clear vacuoles of different sizes, dense bodies, mitochondria, and glycogen granules. Beside the typical small-sized mitochondria, other clear and voluminous mitochondria with small tubular cristae are observable (Figure 4D and Figure 5E). In the labyrinth I, two cell types are observable, columnar cells and cuboidal cells. (a) Columnar cells (Figure 2D) (average height 22 µm) possess an apical nucleus, dilated intercellular spaces, irregular apical microvilli, and irregular basal membrane infoldings associated with mitochondria. The large globular vesicles and cytoplasmic extrusions in these cells contain numerous small vesicles, vacuoles, and, frequently, dense spherical residual bodies. As in the coelomosac region, spherical residual bodies are often observed in the globular vesicles and in the lumen (not shown). (b) In cuboidal cells (EFigures 3A5E) (height 20 µm), the nucleus is centrally located; the main features of these cells include the presence of regular basal infoldings associated with round mitochondria, globules of glycogen, and lysosome-like bodies (Figure 3C). They display many apical swollen mitochondria, tight junctions, and zonula adherens (Figure 3E). Their apical large globular vesicles contain many vacuoles and swollen mitochondria, and no spherical structure is observable (Figure 3B). Vacuoles, lysosome-like bodies, glycogen globules, and mitochondria are consistently observable in close contact (Figure 3D). The labyrinth II cells (Figures 4A4E) are columnar-shaped (average height 27 µm) and their cytoplasm is usually clear. On their basal side, short basal infoldings are associated with mitochondria, vesicles, and numerous and large vacuoles containing fine particles (Figure 4C). Their apical portion and cytoplasmic extrusions contain clear vacuoles, small vesicles, mitochondria, and lysosome-like bodies (Figures 4A and 4D). Besides these cytoplasmic extrusions, well-developed vacuoles and large, globular vesicles containing fine particles of labyrinth II cells bulge into the lumen and are free from the cell body (Figures 4B and 4E).
The bladder cells (Figures 5A5E) present different sizes according to their location. The ventral wall of the bladder is lined by a thin epithelium (average height 15 µm), whereas the lateral and dorsal walls are limited by a thick epithelium (average height 45 µm). The bladder cells are columnar with an apical nucleus and irregular apical microvilli. They are filled with numerous and clear vacuoles of different sizes containing fine particles, frequently surrounded by an electron-dense cisterna, or associated with dense bodies and lysosome-like bodies (Figures 5B and 5E). They possess apical cytoplasmic extrusions into the lumen that contain clear vacuoles; there is no apical globular vesicle (Figures 5C and 5D). Small endocytic vesicles are frequently present in the apical region (Figures 5C and 5D). As in the labyrinth cells, clear and voluminous mitochondria with small tubular cristae are observable in the apical extrusions (Figures 5A and 5D). The basal side of the cells is dense and presents deep membrane infoldings associated with mitochondria, sparse vacuoles, and small, clear vesicles (Figure 5B). The bladder cells possess a thick basal lamina (Figure 5B).
Immunocytochemistry
Discussion and Conclusion To our knowledge, this study is the first ultrastructural investigation of the antennal glands of homarid lobsters. In contrast to the situation in freshwater species, no nephridial tubule was observed between the labyrinth and the bladder. In crayfish, the main function of the nephridial tubule is salt reabsorption, which results in the production of hyposmotic urine, a key adaptation to the low ion concentration of freshwater (Peterson and Loizzi 1974
The most striking features of the coelomosac cells (podocytes) are the presence of basal pedicles, large lateral channels, intracellular large dense bodies, Golgi complex, vesicles, and vacuoles. The cells possess also endocytic vesicles and residual bodies that become detached and pass (as apical globular vesicles) into the lumen of the coelomosac. They are similar to podocytes described in other species of crustaceans particularly in crayfish (Khodabandeh et al. 2005a
The general common features of the epithelial cells of the labyrinth and bladder as observed in the present study are apical microvilli, apical cytoplasmic extrusions, endocytosis vesicles, cytoplasmic vacuoles, and basal plasma membrane infoldings associated with mitochondria. In general, these characters suggest the existence of active ion transport, potentially associated with reabsorption, secretion, or uptake of materials such as glucose, amino acids, and small proteins, and reabsorption of solute and water, respectively. Morphological differences were observed between the different regions of labyrinth I and II. In labyrinth I, we observed two different cell types: columnar and cuboidal. They might be similar cells, but at different physiological states, as previously described in the labyrinth epithelium of the blue crab Callinectes sapidus (Johnson 1980
The bladder cells present different sizes (1550 µm) according to their location. Morphological similarities between the cells of labyrinth II and the bladder suggest functional analogies between these two sites. Because Na+,K+-ATPase was detected in the bladder cells, a last modification of the filtrate would occur in this region of the antennal gland before the release of urine. Investigations of the bladder cells in crayfish and crabs have shown that they are involved in active ion transport (Johnson 1980 In conclusion, labyrinth and bladder cells are involved in different excretory and reabsorption functions. The presence of Na+,K+-ATPase in both structures could be explained in two ways: (a) the enzyme provides only the driving force for the transport of solutes such as sugar or amino acids or 2) the labyrinth and bladder cells are involved in active ion exchanges per se.
Lobsters can be found in coastal waters and estuarine habitats (Jury et al. 1994
Thanks are due to the University of Tarbiat Modarres and Ministry of Science, Research and Technology, Islamic Republic of Iran, for financial aid and support. Special thanks also to Dr. Khosrov Piri, responsible for Iranian student service in Paris, and F. Aujoulat, C. Blasco, E. Grousset, J.P. Selzner of the University of Montpellier II for their technical help.
Received for publication September 29, 2004; accepted February 22, 2005
Ahearn GA, Franco P (1993) Ca2+ transport pathways in brush-border membrane vesicles of crustacean antennal glands. Am J Regulatory. Integr Comp Physiol 256:R1206R1213 Behnke RD, Wong RK, Huse SM, Reshkin SJ, Ahearn NA (1990) Proline transport by brush border membrane vesicles of lobster antennal glands. Am J Physiol 258:F311F320 Behnke RD, Busquets-Turner L, Ahearn GA (1998) Epithelial glucose transport by lobster antennal gland. J Exp Biol 201:33853393[Abstract] Binns R (1969) The physiology of the antennal gland of Carcinus maenas. III. Glucose reabsorption. J Exp Biol 51:1725 Burger JW (1957) The general form of excretion in the lobster, Homarus. Biol Bull Mar Biol Lab Woods Hole 113:207222 Charmantier G, Thuet P, Charmantier-Daures M (1984) La regulation osmotique et ionique chez Homarus gammarus (L.) (Crustacea: Decapoda). J Exp Marine Biol Ecol 76:191199[CrossRef] Charmantier G, Hoand C, Lignot JH, Charmantier-Daures M (2001) Ecophysiological adaptation to salinity throughout a life cycle: a review in Homarid lobsters. J Exp Biol 204:967977[Abstract] Chavez-Crooker P, Garrido N, Ahearn GA (2001) Copper transport by lobster hepatopancreatic epithelial cells separated by centrifugal elutriation: measurements with the fluorescent dye Phen Green. J Exp Biol 20:14331444 Chavez-Crooker P, Garrido N, Ahearn GA (2002) Copper transport by lobster (Homarus americanus) hepatopancreatic mitochondria. J Exp Biol 205:405413 Dall W (1970) Osmoregulation in the lobster Homarus americanus. J Fish Res Board Can 27:11231130 Fuller EG, Highison GJ, Brown F, Bayer C (1989) Ultrastructure of the crayfish antennal gland revealed by scanning and transmission electron microscopy combined with ultrasonic microdissection. J Morph 200:915.[CrossRef] Gross WJ (1967) Glucose absorption from the urinary bladder of a crab. Comp Biochem Physiol 20:313317[CrossRef] Holliday CW, Miller DS (1984) Cellular mechanisms of organic anion transport in crustacean renal tissue. Am Zool 24:275284 Ischiguro J (1975) Fine structure of the antennal gland of the crayfish Procambarus clarkii. J Electron Micros 24:191 Johnson PT (1980) Histology of the Blue Crab Callinectes sapidus. New York, Praeger Jury SH, Kinnison MT, Howell WH, Watson WH III (1994) The behaviour of lobsters in response to reduced salinity. J Exp Mar Biol Ecol 180:2337[CrossRef] Kanli H, Terreros DA (1997) Transepithelial transport and cell volume control in proximal renal tubules from the teleost Carassius auratus. Acta Physiol Scand 160:267276[CrossRef][Medline] Khodabandeh S, Charmantier G, Blasco C, Grousset E, Charmantier-Daures M (2005a) Ontogeny of the antennal glands in the Crayfish, Astacus leptodactylus (Crustacea, Decapoda): anatomical and cell differentiation. Cell Tissue Res 319:153165[CrossRef][Medline] Khodabandeh S, Kutnik M, Aujoulat F, Charmantier G, Charmantier-Daures M (2005b) Ontogeny of the antennal glands in the Crayfish, Astacus leptodactylus (Crustacea, Decapoda): immunolocalization of Na+,K+-ATPase. Cell Tissue Res 319:167174[CrossRef][Medline] Lawton P, Lavalli KL (1995) Postlarval, juvenile, adolescent, and adult ecology. In Factor JR, ed. Biology of the Lobster Homarus americanus. New York, Academic Press Lignot JH, Charmantier G (1999) Immunolocalization of Na+,K+-ATPase in the branchial cavity during the early development of the European lobster Homarus gammarus (Crustacea, Decapoda). J Histochem Cytochem 49:10131023 Lignot JH, Charmantier-Daures M, Charmantier G (2001) Immunolocalization of Na+,K+-ATPase in the organs of the branchial cavity of the European lobster Homarus gammarus (Crustacea, Decapoda). Cell Tissue Res 296:417426 Lignot JH, Susanto GN, Charmantier-Daures M, Charmantier G (2005) Immunolocalization of Na+,K+-ATPase in the branchial cavity during the early development of the crayfish Astacus leptodactylus (Crustacea, Decapoda). Cell Tissue Res 319:331339[CrossRef][Medline] Lucu C, Flik G (1999) Na+,K+-ATPase and Na+/Ca2+ exchange activities in gills of hyperregulating Carcinus maenas. Am J Physiol Regul Comp Physiol 276:490499 Mantel LH, Farmer LL (1983) Osmotic and ionic regulation. In Bliss DE, ed. The Biology of Crustacea, vol. 5. Internal Anatomy and Physiological Regulations. London, Academic Press Mc Mahon BR (2002) Physiological adaptation to environment. In Holdich DM, ed. Biology of the Freshwater Crayfish. Oxford, Blackwell Science Miller DS (1989) Crustacean urinary bladder as a model for vertebrate renal proximal tubule. In Woodhead AD, ed. Nonmammalian Models for Biomedical Research. Boca Raton, FL: CRC Press Miyawaki M, Ukeshima A (1967) On the ultrastructure of the antennal gland epithelium of the crayfish, Procambarus clarkii. J Sci 8:5973 Miyawaki M, Ura T (1969) Absorption and secretion of experimentally injected protein silver by kidney cells of the crayfish. Ann Zoo Jap 42:5662 Peters H (1935) Über den Einfluss des Salzgehlates im Aussenmedium auf den Bau und die Funktion der Exkretionsorgane decapoder Crustacean. Z Morphol Ükol Tiere 30:355381[CrossRef] Peterson DR, Loizzi RF (1974) Ultrastructure of the crayfish kidney, coelomosac, labyrinth, and nephridial canal. J Morphol 142:241264[CrossRef][Medline] Peterson DR, Loizzi RF (1975) Biochemical and cytochemical investigation of Na+,K+-ATPase in the crayfish kidney. Comp Biochem Physiol 49A:763773.[CrossRef] Péqueux A (1995) Osmotic regulation in crustaceans. J Crust Biol 15:160 Pritchard JB, Miller DS (1991) Comparative insights into the mechanisms of renal organic anion and cation secretion. Am J Physiol 261:R1329R1340 Riegel JA (1966) Analysis of formed bodies in urine removed from the crayfish antennal gland by micropuncture. J Exp Biol 44:387395 Riegel JA, Cook MA (1975) Recent studies of excretion in crustaceans. Fortschr Zool 23:4875 Sarver GL, Flynn MA, Holliday CW (1994) Renal Na+,K+-ATPase and osmoregulation in the crayfish Procambarus clarkii. Comp Biochem Physiol 107A:349356[CrossRef] Sesma P, Bayona C, Villaro AC, Vazquez JJ (1983) A microscopic study on the antennal gland of Antrapotamobius ballines (Crustacea, Decapoda). Morfologia Normaly Patologica 7:289301 Susanto GN, Charmantier G (2000) Ontogeny of osmoregulation in the crayfish Astacus leptodactylus. Physiol Biochem Zool 73:169176[CrossRef][Medline] Susanto GN, Charmantier G (2001) Crayfish freshwater adaptation starts in eggs: ontogeny of osmoregulation in embryos of Astacus leptodactylus. J Exp Zool 289:433440[CrossRef][Medline] Takeyasu K, Tamkun MM, Renaud KJ, Fambrough DM (1988) Ouabain sensitive Na+,K+-ATPase activity expressed in mouse L cells by transfection with DNA encoding the Vogt G (2002) Functional anatomy. In Holdich DM, ed. Biology of Freshwater Crayfish. Oxford, Blackwell Science Waite FC (1899) The structure and development of the antennal glands in Homarus americanus Milne-Edwards. Bull Mus Comp Zool Harv 35:151210
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