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  • secretion  (2)
  • Acid-base regulation; Alkalinity, total; Animalia; Aragonite saturation state; Baltic Sea; Benthic animals; Benthos; Bicarbonate ion; Bottles or small containers/Aquaria (〈20 L); Calcification/Dissolution; Calcite saturation state; Calcium; Calcium per individual; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; delta; Experiment; Fluorescence; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Laboratory experiment; Mollusca; Mytilus edulis; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Registration number of species; Replicate; Salinity; Shell length; Shell length, standard deviation; Single species; Species; Temperate; Temperature, water; Time in hours; Type; Uniform resource locator/link to reference  (1)
Document type
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  • 1
    Electronic Resource
    Electronic Resource
    The Na+2Cl–K+ cotransporter in the rectal gland of Squalus acanthias is activated by cell shrinkage (1999)
    Springer
    Pflügers Archiv 438 (1999), S. 165-176 
    Details
    ISSN: 1432-2013
    Keywords: Key words Cell volume ; Cl ; secretion ; Exocrine secretion ; Na+2Cl ; K+ cotransporter ; Phalloidin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Effects of cAMP on Cl– secretion, intracellular Cl– activity and cell volume were studied in isolated perfused rectal gland tubules (RGT) of Squalus acanthias with electrophysiological and fluorescence methods. Recording of equivalent short-circuit current (I sc) showed that cAMP stimulates Na+Cl– secretion in a biphasic manner. The first and rapid phase corresponds to Cl– exit via the respective protein-kinase-A- (PKA-) phosphorylated Cl– conductance. The inhibitory effect of the loop diuretic furosemide (0.5 mmol/l, n=12) indicates that second phase reflects the delayed (1–2 min) activation of the Na+2Cl–K+ cotransporter. During the first phase cytosolic Cl– activity, as monitored by 6-methoxy-N-(3-sulfopropyl) quinolinium (SPQ) fluorescence, fell to 78% (n=23) of the control value. Concomitantly, a transient fall in cell volume was recorded by calcein fluorescence to 92% (n=5) of the control value. Preincubation of the RGT with phalloidin (0.1 mmol/l, n=6) or cytochalasin D (0.1 mmol/l, n=4) almost completely prevented the development of the second phase of I sc activation. When cytosolic Cl– activity was increased by exposing the RGT to a high K+ concentration (25 mmol/l), in the presence of mannitol to prevent volume increases, stimulation was unaffected and biphasic. In contrast, when cell volume was clamped to an increased value (115%, n=8) by removing extracellular NaCl, the second phase was abolished completely (n=11). These data suggest that the primary and key process for triggering the Na+2Cl–K+ cotransport is transient cell shrinkage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004240050895
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The cellular mechanisms of Cl– secretion induced by C-type natriuretic peptide (CNP). Experiments on isolated in vitro perfused rectal gland tubules of Squalus acanthias (1999)
    Springer
    Pflügers Archiv 438 (1999), S. 15-22 
    Details
    ISSN: 1432-2013
    Keywords: Key words cGMP ; Cl ; secretion ; C-type natriuretic peptide ; NaCl secretion ; Squalus acanthia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We have examined the mechanism whereby C-type natriuretic peptide (CNP), an agonist acting through the second messenger cGMP, enhances NaCl secretion in the rectal gland of Squalus acanthias. Single rectal gland tubules (RGT) were dissected manually, perfused in vitro and equivalent short-circuit current [I sc=transepithelial voltage/transepithelial resistance (R te)] as well as basolateral membrane voltage (V bl) were measured. CNP was added to luminal and basolateral perfusates at concentrations between 1 and 1000 nmol/l and its effects on the above parameters were compared to those of a ”stimulation cocktail” (Stim, containing dibutyryl cAMP, adenosine and forskolin) that maximally enhances cytosolic cAMP, and other agonists and hormones such as guanylin, vasoactive intestinal peptide (VIP), and adenosine. CNP had no effect from the luminal side (n=6). Its effects from the basolateral side consisted of a substantial increase in I sc (–31.6±7.7 to –316±82.2 µA/cm2, n=15). CNP significantly depolarized the luminal membrane from –87.4±1.0 to –82.3±2.6 mV (n=12). V bl was not changed (n=12) but the fractional conductance for K+ was increased (n=3). These effects were qualitatively and even quantitatively comparable to those of other agonists acting via cytosolic cAMP, but were less marked than those caused by Stim (n=64). The effects of VIP and CNP on I sc were not additive (n=5). The cytosolic Ca2+ concentration ([Ca2+]i) was monitored using the fura-2 fluorescence ratio (FFR 340/380 nm) and it was found that CNP, like agonists acting via cAMP, enhances FFR significantly from 1.02±0.05 to 1.32±0.05 (n=8) with a time constant in the 1–2 min in range. Our data suggest that CNP, acting via the second messenger cGMP, induces a marked increase in I sc in the rectal gland. The concomitant fall in R te corresponds to increases in the luminal membrane Cl– conductance and in the basolateral membrane K+ conductance. The latter effect is probably due to an increase in [Ca2+]i.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004240050874
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    Paper (German National Licenses)
    Fulltext
  • 3
    facet.materialart.
    Unknown
    Seawater carbonate chemistry and calcifying fluid carbonate chemistry, shell length of Mussel larvae (2017)
    PANGAEA
    Details
    Publication Date: 2024-03-15
    Description: Understanding mollusk calcification sensitivity to ocean acidification (OA) requires a better knowledge of calcification mechanisms. Especially in rapidly calcifying larval stages, mechanisms of shell formation are largely unexplored—yet these are the most vulnerable life stages. Here we find rapid generation of crystalline shell material in mussel larvae. We find no evidence for intracellular CaCO3 formation, indicating that mineral formation could be constrained to the calcifying space beneath the shell. Using microelectrodes we show that larvae can increase pH and [CO3]2−beneath the growing shell, leading to a ~1.5-fold elevation in calcium carbonate saturation state (Omega arag). Larvae exposed to OA exhibit a drop in pH, [CO3]2− and Omega arag at the site of calcification, which correlates with decreased shell growth, and, eventually, shell dissolution. Our findings help explain why bivalve larvae can form shells under moderate acidification scenarios and provide a direct link between ocean carbonate chemistry and larval calcification rate.
    Keywords: Acid-base regulation; Alkalinity, total; Animalia; Aragonite saturation state; Baltic Sea; Benthic animals; Benthos; Bicarbonate ion; Bottles or small containers/Aquaria (〈20 L); Calcification/Dissolution; Calcite saturation state; Calcium; Calcium per individual; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; delta; Experiment; Fluorescence; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Laboratory experiment; Mollusca; Mytilus edulis; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Registration number of species; Replicate; Salinity; Shell length; Shell length, standard deviation; Single species; Species; Temperate; Temperature, water; Time in hours; Type; Uniform resource locator/link to reference
    Type: Dataset
    Format: text/tab-separated-values, 13036 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
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