The hypobranchial gland in the Bivalvia

1977 ◽  
Vol 55 (8) ◽  
pp. 1225-1234 ◽  
Author(s):  
Brian Morton
Keyword(s):  
Corbicula Fluminea ◽  
Mantle Cavity ◽  
Waste Material ◽  
Brood Pouch ◽  
Mucous Cells ◽  
Primitive Function ◽  
Sphaerium Corneum ◽  
Regenerative Cells ◽  
Suprabranchial Chamber

The hypobranchial gland of the protobranchs Nucula nucleus and Solemya parkinsoni comprises mucous cells flanked by inversely conical and ciliated regenerative cells. A similar structure occurs in the filibranch Monia squama and in the eulamellibranchs Fimbria fimbriata and Corbicula fluminea except that in the two latter the conical cells are not ciliated and in C. fluminea they are also secretory.The primitive function of the hypobranchial gland was the consolidation, in a mucous stream, of waste material for expulsion via the exhalant aperture. The evolution of the filibranch and eulamellibranch ctenidia dividing the mantle cavity into infrabranchial and suprabranchial chambers with waste material removed via the inhalant aperture abrogated the need for such a structure. It has, however, been retained in some filibranchs where the ctenidia are possibly less efficient.In Nucula delphinodonta the hypobranchial gland secretes a brood pouch attached to the shell, Enhancement of this function in lamellibranch bivalves, notably C. fluminea and possibly F. fimbriata, has resulted in the gland functioning as an organ for the nutrition of developing larvae incubated in the suprabranchial chamber. An epithelium with regenerative cells of different structure occurs in the similarly incubatory Sphaerium corneum.

scholarly journals Vodní měkkýši Labe mezi Pardubicemi a Hřenskem [Aquatic molluscs of the Elbe River between Pardubice and Hřensko (Czech Republic)]

2005 ◽  
Vol 3 ◽  
pp. 78-88
Author(s):  
Luboš Beran
Keyword(s):  
Czech Republic ◽  
Dreissena Polymorpha ◽  
Native Species ◽  
Corbicula Fluminea ◽  
Elbe River ◽  
Bithynia Tentaculata ◽  
Sphaerium Corneum ◽  
Theodoxus Fluviatilis ◽  
The Elbe River ◽  
Radix Auricularia

Aquatic molluscs of the Elbe River between Němčice (near Pardubice, Eastern Bohemia, Czech Republic) and Hřensko (Northern Bohemia, Czech Republic) at 27 localities were investigated from 1994 to 2004. Altogether 40 species (24 gastropods, 16 bivalves) from 77 species known on the territory of the Czech Republic were found at sites under study. A gradual invasion of 6 non-native species (Potamopyrgus antipodarum, Physella acuta, Menetus dilatatus, Ferrissia clessiniana, Corbicula fluminea) and an extinction of another species (Theodoxus fluviatilis, Planorbis carinatus, Unio crassus, Pisidium amnicum) were documented in comparison with historical records. Rare mussel Pseudanodonta complanata and rare pea mussel Pisidium moitessierianum were found at several localities under study and these finds document survival of these bivalves in the Elbe River. Molluscan communities of particular localities were most often usually compounded from species Viviparus viviparus (downstream of loc. 9), Bithynia tentaculata, Radix auricularia, Radix ampla, Unio pictorum, Anodonta anatina, Corbicula fluminea (downstream of loc. 8), Sphaerium rivicola (downstream of loc. 7), Sphaerium corneum s. lat., Pisidium supinum, Dreissena polymorpha.

scholarly journals Vodní měkkýši Labe mezi Pardubicemi a Hřenskem [Aquatic molluscs of the Elbe River between Pardubice and Hřensko (Czech Republic)]

2005 ◽  
Vol 3 ◽  
pp. 78-88
Author(s):  
Luboš Beran
Keyword(s):  
Czech Republic ◽  
Dreissena Polymorpha ◽  
Native Species ◽  
Corbicula Fluminea ◽  
Elbe River ◽  
Bithynia Tentaculata ◽  
Sphaerium Corneum ◽  
Theodoxus Fluviatilis ◽  
The Elbe River ◽  
Radix Auricularia

Aquatic molluscs of the Elbe River between Němčice (near Pardubice, Eastern Bohemia, Czech Republic) and Hřensko (Northern Bohemia, Czech Republic) at 27 localities were investigated from 1994 to 2004. Altogether 40 species (24 gastropods, 16 bivalves) from 77 species known on the territory of the Czech Republic were found at sites under study. A gradual invasion of 6 non-native species (Potamopyrgus antipodarum, Physella acuta, Menetus dilatatus, Ferrissia clessiniana, Corbicula fluminea) and an extinction of another species (Theodoxus fluviatilis, Planorbis carinatus, Unio crassus, Pisidium amnicum) were documented in comparison with historical records. Rare mussel Pseudanodonta complanata and rare pea mussel Pisidium moitessierianum were found at several localities under study and these finds document survival of these bivalves in the Elbe River. Molluscan communities of particular localities were most often usually compounded from species Viviparus viviparus (downstream of loc. 9), Bithynia tentaculata, Radix auricularia, Radix ampla, Unio pictorum, Anodonta anatina, Corbicula fluminea (downstream of loc. 8), Sphaerium rivicola (downstream of loc. 7), Sphaerium corneum s. lat., Pisidium supinum, Dreissena polymorpha.

Cytoplasmic Invaginations in Trophoblasts and Epithelial Cells of Rat

1971 ◽  
Vol 29 ◽  
pp. 524-525
Author(s):  
Iracema M. Baccarini
Keyword(s):  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Nuclear Inclusions ◽  
Mucous Cells ◽  
Electron Microscopic ◽  
Cervical Epithelium ◽  
Intact Membrane ◽  
Microscopic Studies ◽  
Abnormal Cells ◽  
Nuclear Features

Some morphological nuclear features (invaginations) in normal and abnormal cells have been described in several electron microscopic studies. They have been referred to by others as blebs, loops, pockets, sheets, bodies, nuclear inclusions and cytoplasmic invaginations. Identical appearing structures were found in cells of the uterine cervical epithelium, in trophoblasts of blastocysts and in trophoblasts of rat placenta.Methods. Uterine cervix (normal rats), rat placenta (9-10 days gestation) and blastocyst were placed in 3% glutarahdehyde for 3 hours. The tissue was washed in phosphate buffer for 24 hours, postfixed in 1%. buffered osmium tetroxide for 1-2 hours and embedded in epon araldite. Sections were double stained with uranyl acetate and lead citrate and viewed in E. M. Siemens 200.Observations. Nuclear invaginations were found in basal, parabasal and mucous cells of the cervix epithelium, in trophoblasts of blastocyst and in trophoblasts of placenta. An oval, round or elongated invagination contained heterogenously cytoplasm surrounded by a double intact membrane; usually several invaginations were found in the same nucleus.

Control of Secretory Production in the Isopod Hepatopancreas

1972 ◽  
Vol 30 ◽  
pp. 166-167
Author(s):  
John W. Roberts ◽  
E. R. Witkus
Keyword(s):  
B Cells ◽  
Morphological Data ◽  
Secretory Product ◽  
Secretory Function ◽  
Secretory Material ◽  
Blind Ending ◽  
Secretory Production ◽  
Regenerative Cells ◽  
Immature Cells ◽  
And Storage

The isopod hepatopancreas, as exemplified by Oniscus ascellus. is comprised of four blind-ending diverticula. The regenerative cells at the tip of each diverticula differentiate into either club-shaped B-cells, which serve a secretory function, or into conoid S-cells, which serve in the absorption and storage of nutrients.The glandular B-cells begin producing secretory material with the development of rough endoplasmic reticulum during their process of maturation from the undifferentiated regenerative cells. Cytochemical and morphological data indicate that the hepatopancreas sequentially produces two types of secretory material within the large club-shaped cells. The production of the carbohydrate-like secretory product in immature cells seems to be phased out as the production of the osmiophilic secretion was phased in as the cell matured.

The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

1994 ◽  
Vol 52 ◽  
pp. 178-179
Author(s):  
Nancy R. Wallace ◽  
Craig C. Freudenrich ◽  
Karl Wilbur ◽  
Peter Ingram ◽  
Ann LeFurgey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Course ◽  
Vertical Plane ◽  
Mantle Cavity ◽  
Qualitative Assessment ◽  
Calcium Deposition ◽  
Free Swimming ◽  
Freeze Dried ◽  
Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

Helicobacter pylori infection produces expression of secretory component in gastric mucous cells

2001 ◽  
Vol 120 (5) ◽  
pp. A708-A709
Author(s):  
T KANEKO ◽  
H OTA ◽  
M HAYAMA ◽  
K NAKAJIMA ◽  
A YOSHIZAWA ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Secretory Component ◽  
Helicobacter Pylori Infection ◽  
Mucous Cells ◽  
Gastric Mucous

Modelling heavy metal mobilisation in solid waste deposits - a predictive tool for environmental risk assessment

1999 ◽  
Vol 39 (10-11) ◽  
pp. 193-196
Author(s):  
J. Petersen ◽  
J. G. Petrie
Keyword(s):  
Heavy Metal ◽  
Solid Waste ◽  
Environmental Risk ◽  
Mechanistic Model ◽  
Small Sample ◽  
Waste Material ◽  
Metal Species ◽  
Model Parameters ◽  
Assessment Methodology ◽  
Predictive Tool

The release of heavy metal species from deposits of solid waste materials originating from minerals processing operations poses a serious environmental risk should such species migrate beyond the boundaries of the deposit into the surrounding environment. Legislation increasingly places the liability for wastes with the operators of the process that generates them. The costs for long-term monitoring and clean-up following a potential critical leakage have to be factored in the overall project plan from the outset. Thus assessment of the potential for a particular waste material to generate a harmful leachate is directly relevant for estimating the environmental risk associated with the planned disposal operation. A rigorous mechanistic model is proposed, which allows prediction of the time-dependent generation of a leachate from a solid mineral waste deposit. Model parameters are obtained from a suitably designed laboratory waste assessment methodology on a relatively small sample of the prospective waste material. The parameters are not specific to the laboratory environment in which they were obtained but are valid also for full-scale heap modelling. In this way the model, combined with the assessment methodology, becomes a powerful tool for meaningful assessment of the risks associated with solid waste disposal strategies.

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