Role of gill Na+ + K+ ‐dependent ATPase in acclimation of blue crabs (Callinectes sapidus) to low salinity

Towle, David W.; Palmer, Gloria E.; Harris, John Lewis

doi:10.1002/jez.1401960306

Cited by 169 publications

(44 citation statements)

References 21 publications

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“…Current knowledge on hypoosmotic acclimation in FW fish and crustaceans suggests that the predominant strategies employed in ion-poor conditions are to 1) increase ion uptake from the external medium and 2) reduce passive ion loss (31,47,68). Increased ion uptake is facilitated by increased expression and activity of ion transporters in the osmoregulatory tissues (17,18,26,32,48,59,60,71). In the euryhaline killifish Fundulus heteroclitus, increased Na ϩ -K ϩ -ATPase (NKA) activity and NKA ␣1a mRNA expression are observed in the gill following FW transfer (48).…”

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confidence: 99%

Larvae of the midge Chironomus riparius possess two distinct mechanisms for ionoregulation in response to ion-poor conditions

Nguyen

Donini

2010

American Journal of Physiology-Regulatory, Integrative and Comp

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Nguyen H, Donini A. Larvae of the midge Chironomus riparius possess two distinct mechanisms for ionoregulation in response to ion-poor conditions. Am J Physiol Regul Integr Comp Physiol 299: R762-R773, 2010. First published July 14, 2010 doi:10.1152/ajpregu.00745.2009.-This study examined the role of the anal papillae of the freshwater (FW) chironomid larva Chironomus riparius in ionoregulation under ion-poor conditions. The scanning ion-selective electrode technique (SIET) was utilized to characterize the species, direction, and rates of inorganic ion transport by the anal papillae following acute and long-term exposure to ion-poor water (IPW). The major inorganic ions in the hemolymph of larvae treated as above were measured using standard ion-selective microelectrodes. The anal papillae of C. riparius are sites of net NaCl uptake and H ϩ secretion under FW and IPW conditions and are not likely to be a major contributor of K ϩ exchange. Acute and long-term exposure to IPW increased total net transport of Na ϩ , Cl Ϫ , and H ϩ by the anal papillae, but the mechanisms underlying the increase under the two conditions were different. Acute IPW exposure increased the magnitude of net ion fluxes at sites along the anal papillae, while long-term IPW exposure resulted in increased size of the anal papillae with no change in the magnitude of net ion fluxes. The contribution of the anal papillae to observed alterations of hemolymph ion activities upon exposure to IPW is discussed. Inhibitors of the Na ϩ /H ϩ exchangers (EIPA) and carbonic anhydrase (methazolamide) provide evidence for Na ϩ /H ϩ and Cl Ϫ /HCO 3 Ϫ exchange mechanisms in the anal papillae. This study demonstrates that C. riparius larvae employ two different mechanisms to upregulate the total net transport of ions by the anal papillae, and these mechanisms are at least partially responsible for regulating hemolymph ion activity. chironomid; anal papilla; transepithelial ion transport; inorganic ions; homeostasis HOMEOSTATIC REGULATION OF the ionic and osmotic composition of the blood is critical for survival. Aquatic animals are common inhabitants of dilute freshwater (FW) environments, which are less concentrated than their blood, and thus, are faced with a number of ionic and osmotic challenges in the regulation of salt and water balance (25,31,35,37,41). The paucity of ions in the external medium establishes diffusional ion gradients that favor the osmotic influx of water and passive loss of ions. To counteract the water uptake and dilution of the blood, large amounts of dilute hypotonic urine are produced (6,25,31). To maintain ion balance, ions are actively absorbed from the external medium to replenish the ions lost through excretion and metabolic processes (25,31,44,54,66).FW habitats are variable, and environmental salinity can fluctuate with changes in climate that can lead to dilution through rainfall or concentration through evaporation (43). One of the principal difficulties in assessing the effects of climate change on the environment is the ...

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confidence: 99%

Larvae of the midge Chironomus riparius possess two distinct mechanisms for ionoregulation in response to ion-poor conditions

Nguyen

Donini

2010

American Journal of Physiology-Regulatory, Integrative and Comp

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“…During the molting process, a large net influx of water is crucial for increasing the animal's hydrostatic pressure in order to expand the body and break open the old exoskeleton. The acclimation of euryhaline crustaceans to dilute salinity is accompanied by decreased branchial water permeability [33], requiring increased Na/K-ATPase activity to establish an ion gradient for water influx to occur [19,34]. The significant increases observed in the Na/K-ATPase levels in the late premolt stage and postmolt stage in this study may indicate that Na/K-ATPase is involved in water uptake at molting.…”

Section: Discussionmentioning

confidence: 56%

Carbonic anhydrase and Na/K-ATPase activities during the molt cycle of low salinity-reared white shrimp Litopenaeus vannamei

et al. 2010

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Changes in hemolymph osmolality, ion concentrations, and enzymatic activities of carbonic anhydrase (CA) in the gills and epidermal tissue, and Na/K-ATPase in the gills during the molt cycle were investigated in the white shrimp Litopenaeus vannamei. Hemolymph osmolality was high in the intermolt and early premolt stages, but started to decrease prior to ecdysis through to postmolt stages A and B. Changes in Na ? and Cl -ion concentrations paralleled those in hemolymph osmolality. CA activity levels in the anterior and posterior gills were low at intermolt stage C 0 and premolt stage D 0 , and maximum at premolt stage D 3 . In the epidermal tissue, activity was relatively high at intermolt stage C 0 and premolt stage D 0 , but fluctuated towards premolt stage D 3 and postmolt stage A. On the other hand, Na/K-ATPase activity in the gills decreased between intermolt stage C 0 and premolt stage D 2 , but increased at premolt stage D 3 and postmolt stage A. The changes in patterns of CA activity during the molt cycle suggest that CA may be involved in supplying counter-ions for Na ? and Cl -uptake during molting. Branchial Na/K-ATPase appears to be involved in producing local osmotic gradients in order to support water influx across the epithelium.

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“…69 The role of the NKA in regulating osmotic disturbances in crustaceans was first investigated using the blue crab, Callinectes sapidus acclimated to low salinities. 70 Further studies identified the gill as the most important site of osmotic regulation and discovered transporters and mechanisms that allowed some crustacean species to actively regulate extracellular osmolarity against steep osmotic gradients. 71,72 Although the existence of the NKA located in branchial epithelia of the cuttlefish Sepia officinalis was revealed using enzymatic assays in the late 70 ties, its role in branchial ion regulation was less well understood.…”

Section: The Ph Regulatory Machinerymentioning

confidence: 99%

Recent advances in understanding trans-epithelial acid-base regulation and excretion mechanisms in cephalopods

Hwang

Tseng

2015

Tissue Barriers

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Cephalopods have evolved complex sensory systems and an active lifestyle to compete with fish for similar resources in the marine environment. Their highly active lifestyle and their extensive protein metabolism has led to substantial acid-base regulatory abilities enabling these organisms to cope with CO 2 induced acid-base disturbances. In convergence to teleost, cephalopods possess an ontogeny-dependent shift in ion-regulatory epithelia with epidermal ionocytes being the major site of embryonic acid-base regulation and ammonia excretion, while gill epithelia take these functions in adults. Although the basic morphology and excretory function of gill epithelia in cephalopods were outlined almost half a century ago, modern immunohistological and molecular techniques are bringing new insights to the mechanistic basis of acidbase regulation and excretion of nitrogenous waste products (e.g. NH 3 /NH 4 C ) across ion regulatory epithelia of cephalopods. Using cephalopods as an invertebrate model, recent findings reveal partly conserved mechanisms but also novel aspects of acid-base regulation and nitrogen excretion in these exclusively marine animals. Comparative studies using a range of marine invertebrates will create a novel and exciting research direction addressing the evolution of pH regulatory and excretory systems.

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Role of gill Na⁺ + K⁺ ‐dependent ATPase in acclimation of blue crabs (Callinectes sapidus) to low salinity

Cited by 169 publications

References 21 publications

Larvae of the midge Chironomus riparius possess two distinct mechanisms for ionoregulation in response to ion-poor conditions

Larvae of the midge Chironomus riparius possess two distinct mechanisms for ionoregulation in response to ion-poor conditions

Carbonic anhydrase and Na/K-ATPase activities during the molt cycle of low salinity-reared white shrimp Litopenaeus vannamei

Recent advances in understanding trans-epithelial acid-base regulation and excretion mechanisms in cephalopods

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