Some ultrastructural features of the nuchal organ of <i>Daphnia magna</i> Straus (Crustacea: Branchiopoda)

Halcrow, K.

doi:10.1139/z82-169

Cited by 17 publications

(14 citation statements)

References 15 publications

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“…Animals show a wide variety of physiological adaptations to maintain ionoregulatory homeostasis in a range of salinities while minimizing the expenditure of energy. Crustaceans cope with challenges imposed by variations in environmental ionic composition through structural, biochemical, and physiological changes (Halcrow 1982; Aladin and Potts 1995; Bianchini and Wood 2008). As in most invertebrates, the osmolality of crustacean hemolymph is due mostly to inorganic ions, especially Na + and Cl − .…”

Section: Discussionmentioning

confidence: 99%

Alterations in Hemolymph Ion Concentrations and pH in Adult Daphnia magna in Response to Elevations in Major Ion Concentrations in Freshwater

Morris

Sakarya

Koh

et al. 2020

Enviro Toxic and Chemistry

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Increases in the concentrations of major ions (Na+, K+, Ca2+, Mg2+, Cl−) in freshwater are a growing concern for ecosystem health. These increases may originate from anthropogenic activities such as road deicing, fracking spills, mining, and fertilizer application and have detrimental effects on freshwater organisms through disturbances in ionoregulation and acid–base balance. The cladoceran Daphnia magna is adapted for active ion uptake and reduction of ion loss to maintain osmotic balance, but alterations in ionic composition of the environmental water are associated with toxicity. In the present study, hemolymph ion concentrations were measured using ion‐selective microelectrode techniques. Increases in the hemolymph concentrations of Na+ and K+ correspond to elevations in the concentrations of these ions in ambient water. Water concentrations associated with sustained increases in hemolymph ion concentrations correlate well with median lethal concentration values from previous toxicology studies, indicating that Na+ and K+ concentrations in hemolymph may predict toxicity. When water K+ concentration is increased, a simultaneous increase in water Na+ concentration mitigates the increase in hemolymph K+ concentration, a finding which is consistent with the reported mitigation of K+ toxicity by Na+. When ambient concentrations of K+, Na+, and Cl− are increased, not only is there a rise in hemolymph ion concentration but hemolymph pH is altered and pH regulation appears to be prioritized over regulation of hemolymph Na+, K+, and Cl− in D. magna. Environ Toxicol Chem 2021;40:366–379. © 2020 SETAC

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Section: Discussionmentioning

confidence: 99%

Alterations in Hemolymph Ion Concentrations and pH in Adult Daphnia magna in Response to Elevations in Major Ion Concentrations in Freshwater

Morris

Sakarya

Koh

et al. 2020

Enviro Toxic and Chemistry

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“…In freshwater forms, these include the nuchal gland, or neck organ, with ion transporting cells for salt uptake, and excretory organs for water excretion. The neck organ degenerates at hatch in those forms which develop epipodites but is otherwise retained (Halcrow, 1982;Aladin, 1983;Aladin and Valdivia Villar, 1987;Aladin and Potts, 1995).…”

Section: Ontogeny Of Osmoregulation In Embryos: External Developmentmentioning

confidence: 99%

Ontogeny of Osmoregulation in Crustaceans: The Embryonic Phase1

Charmantier

Charmantier‐Daures

2001

American Zoologist

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SYNOPSIS. Following a brief overview of the patterns of ontogeny of osmoregulation in postembryonic stages, this review concentrates on the ontogeny of osmoregulation during the embryonic development of crustaceans, particularly in those species living under variable or extreme salinity conditions and whose hatchlings osmoregulate at hatch. Two situations are considered, internal development of the embryos in closed incubating, brood or marsupial pouches, and external development in eggs exposed to the external medium. In both cases, embryos are osmoprotected from the external salinity level and variation, either by the female pouches or by the egg envelopes. The mechanisms of osmoprotection are discussed. During embryonic life, temporary or definitive osmoregulatory organs develop, with ion transporting cells and enzymes such as Na ؉-K ؉ ATPase, permitting the embryos and then the hatchlings to osmoregulate and tolerate the external salinity.

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“…The ultrastructure of the osmoregulatory dorsal organ has been described for several crustacean species (Lake et al 1974;Halcrow 1982Halcrow , 1985Lowy and Conte 1985;Hosfeld and Schminke 1997;Hosfeld 1999). Because of the simultaneous occurrence of the sensory dorsal organ and the osmoregulatory dorsal organ in two species of the Syncarida Anaspidacea (Swain et al 1970;Lake et al 1974;Laverack et al 1996), it can be stated that they are really two separate structures.…”

Section: Sensory Modality Of Lattice Organsmentioning

confidence: 99%

TEM studies on the lattice organs of cirripede cypris larvae (Crustacea, Thecostraca, Cirripedia)

Høeg¹,

Hosfeld²,

Jensen³

1998

Zoomorphology

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Some ultrastructural features of the nuchal organ of Daphnia magna Straus (Crustacea: Branchiopoda)

Cited by 17 publications

References 15 publications

Alterations in Hemolymph Ion Concentrations and pH in Adult Daphnia magna in Response to Elevations in Major Ion Concentrations in Freshwater

Alterations in Hemolymph Ion Concentrations and pH in Adult Daphnia magna in Response to Elevations in Major Ion Concentrations in Freshwater

Ontogeny of Osmoregulation in Crustaceans: The Embryonic Phase1

TEM studies on the lattice organs of cirripede cypris larvae (Crustacea, Thecostraca, Cirripedia)

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