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1.
Immunolocalization of Na+/K+‐ATPase,Na+/K+/2Cl− co‐transporter (NKCC) and mRNA expression of Na+/K+‐ATPase α‐subunit during short‐term salinity transfer in the gills of Persian sturgeon (Acipenser persicus,Borodin, 1897) juveniles 下载免费PDF全文
S. A. Shirangi M. R. Kalbassi S. Khodabandeh H. Jafarian J.‐H. Lignot 《Zeitschrift fur angewandte Ichthyologie》2017,33(3):347-353
The study tests the physiological responses of Persian sturgeon, Acipenser persicus, during the abrupt release of juveniles from freshwater (FW) into brackish waters (BW = 11‰) of the Caspian Sea. Fish weight at release was 2‐3 g (2.55 ± 0.41 g; 8.8 ± 0.58 cm TL). Totals of 160 individuals were randomly distributed into four fiber‐glass aerated tanks (volume 60‐L). Two tanks served as controls (FW groups), and two as exposure tanks for BW (Caspian Sea water = CSW). Fish were sampled at 0, 3, 6, 12, 24, 48 and 96 hr after abrupt transfer to CSW. Plasma osmolality, immunolocalization of Na+, K+ ‐ATPase (NKA) and Na+/K+/2Cl– (NKCC) Co‐transporter, NKA activity and the NKA α‐subunit mRNA expression were analyzed. Blood osmolality of fish transferred from FW to CSW increased significantly within hours post‐transfer (p < .05) and remained at a high level for up to 96 hr. Immunolocalization of NKCC indicated co‐localization with NKA in the chloride cells in the gill epithelium. A partial sequence of the NKA α‐subunit (632 bp) is described. Its expression levels were up‐regulated at 12 and 48 hr following salinity transfer (p < .05). However, NKA activity sharply increased in CSW specimens by almost 2.8‐fold (p < .05) between 48 and 96 hr after transfer. Gill NKCC co‐transporter abundance increased, coinciding with increased gill NKA activity. The increased activity of NKCC during salt excretion in CSW may lead to an influx of Na+ into the chloride cells. Consequently, NKA activity increases to maintain intracellular Na+ homeostasis. 相似文献
2.
Yang WK Kang CK Chen TY Chang WB Lee TH 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(7):953-964
In the branchial mitochondrion-rich (MR) cells of euryhaline teleosts, the Na+/K+/2Cl− cotransporter (NKCC) is an important membrane protein that maintains the internal Cl− concentration, and the branchial Na+/K+-ATPase (NKA) is crucial for providing the driving force for many other ion-transporting systems. Hence this study used the
sailfin molly (Poecilia latipinna), an introduced aquarium fish in Taiwan, to reveal that the potential roles of NKCC and NKA in sailfin molly were correlated
to fish survival rates upon salinity challenge. Higher levels of branchial NKCC were found in seawater (SW)-acclimated sailfin
molly compared to freshwater (FW)-acclimated individuals. Transfer of the sailfin molly from SW to FW revealed that the expression
of the NKCC and NKA proteins in the gills was retained over 7 days in order to maintain hypoosmoregulatory endurance. Meanwhile,
their survival rates after transfer to SW varied with the duration of FW-exposure and decreased significantly when the SW-acclimated
individuals were acclimated to FW for 21 days. Double immunofluorescence staining showed that in SW-acclimated sailfin molly,
NKCC signals were expressed on the basolateral membrane of MR cells, whereas in FW-acclimated molly, they were expressed on
the apical membrane. This study illustrated the correlation between the gradual reductions in expression of branchial NKCC
and NKA (i.e., the hypoosmoregulatory endurance) and decreasing survival rates after hyperosmotic challenge in sailfin molly. 相似文献
3.
Zeying Wang Genlin Wang Jingmin Huang Qiuling Li Changfa Wang Jifeng Zhong 《Molecular biology reports》2011,38(3):1749-1755
Genetic association analysis was applied to examine the effect of the Na+/K+-ATPase beta 2 subunit (ATP1B2) gene on rectal temperature, milk traits, K+ levels and Na+/K+-ATPase (NKA) activity in the red blood cells of 1001 Chinese Holstein cows under normal and heat-stress conditions. We detected
two novel single nucleotide polymorphisms, G2258A and C2833T, in the second and fourth introns, respectively, of ATP1B2. G2258A significantly affected milk fat content (P < 0.05) and 305-day milk yield (P < 0.01), but not milk protein content. C2833T significantly affected milk protein content (P < 0.01) and 305-day milk yield (P < 0.05), but not milk fat content. Calculated gene substitution effects suggested that A to G substitution in G2258A, and
T to C substitution in C2833T, positively affected milk fat content, 305-day milk yield and somatic cell score, but negatively
affected milk protein content. We also detected significant variation in milk fat content, milk protein content, 305-day milk
yield and somatic cell scores (P < 0.05 or P < 0.01) among the nine ATP1B2 haplotypes. Under heat-stress, the C2833T polymorphism was significantly related to rectal temperature (P < 0.01), red blood cell K+ levels, NKA activity and milk yield (P < 0.05). Cows with the TT genotype showed the desirable characteristics of low rectal temperature and red blood cell K+, low decline rate in milk yield and red blood cell NKA activity. This study suggests that the ATP1B2 single nucleotide polymorphism C2833T is a genetic marker of heat-resistance traits in Chinese Holstein cows. 相似文献
4.
Mechanisms of seawater acclimation in a primitive,anadromous fish,the green sturgeon 总被引:1,自引:0,他引:1
Peter J. Allen Joseph J. CechJr Dietmar Kültz 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(7):903-920
Relatively little is known about salinity acclimation in the primitive groups of fishes. To test whether physiological preparative
changes occur and to investigate the mechanisms of salinity acclimation, anadromous green sturgeon, Acipenser medirostris (Chondrostei) of three different ages (100, 170, and 533 dph) were acclimated for 7 weeks to three different salinities (<3,
10, and 33 ppt). Gill, kidney, pyloric caeca, and spiral intestine tissues were assayed for Na+, K+-ATPase activity; and gills were analyzed for mitochondria-rich cell (MRC) size, abundance, localization and Na+, K+-ATPase content. Kidneys were analyzed for Na+, K+-ATPase localization and the gastro-intestinal tract (GIT) was assessed for changes in ion and base content. Na+, K+-ATPase activities increased in the gills and decreased in the kidneys with increasing salinity. Gill MRCs increased in size
and decreased in relative abundance with fish size/age. Gill MRC Na+, K+-ATPase content (e.g., ion-pumping capacity) was proportional to MRC size, indicating greater abilities to regulate ions with
size/age. Developmental/ontogenetic changes were seen in the rapid increases in gill MRC size and lamellar length between
100 and 170 dph. Na+, K+-ATPase activities increased fourfold in the pyloric caeca in 33 ppt, presumably due to increased salt and water absorption
as indicated by GIT fluids, solids, and ion concentrations. In contrast to teleosts, a greater proportion of base (HCO3
− and 2CO3
2−) was found in intestinal precipitates than fluids. Green sturgeon osmo- and ionoregulate with similar mechanisms to more-derived
teleosts, indicating the importance of these mechanisms during the evolution of fishes, although salinity acclimation may
be more dependent on body size. 相似文献
5.
L.S. Babonis K.A. Hyndman H.B. Lillywhite D.H. Evans 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2009,154(4):535-540
The sublingual salt gland is the primary site of salt excretion in sea snakes; however, little is known about the mechanisms mediating ion excretion. Na+/K+–ATPase (NKA) and Na+/K+/2Cl− cotransporter (NKCC) are two proteins known to regulate membrane potential and drive salt secretion in most vertebrate secretory cells. We hypothesized that NKA and NKCC would localize to the basolateral membranes of the principal cells comprising the tubular epithelia of sea snake salt glands. Although there is evidence of NKA activity in salt glands from several species of sea snake, the localization of NKA and NKCC and other potential ion transporters remains unstudied. Using histology and immunohistochemistry, we localized NKA and NKCC in salt glands from three species of laticaudine sea snake: Laticauda semifasciata, L. laticaudata, and L. colubrina. Antibody specificity was confirmed using Western blots. The compound tubular glands of all three species were found to be composed of serous secretory epithelia, and NKA and NKCC were abundant in the basolateral membranes. These results are consistent with the morphology of secretory epithelia found in the rectal salt glands of marine elasmobranchs, the nasal glands of marine birds and the gills of teleost fishes, suggesting a similar function in regulating ion secretion. 相似文献
6.
Tipsmark CK Madsen SS Seidelin M Christensen AS Cutler CP Cramb G 《The Journal of experimental zoology》2002,293(2):106-118
7.
Sardella BA Sanmarti E Kültz D 《Journal of experimental zoology. Part A, Ecological genetics and physiology》2008,309(8):477-483
We investigated the effect of environmental salinity on the upper thermal tolerance of green sturgeon (Acipenser medirostris), a threatened species whose natural habitat is vulnerable to temperature and salinity variation as a result of global climate change. Freshwater (FW)-reared sturgeon were gradually acclimated to salinities representing FW, estuary water (EST), or San Francisco Bay water (BAY) at 18 degrees C, and their critical thermal maximum (CTMax) was measured by increasing temperature 0.3 degrees C/min until branchial ventilation ceased. CTMax was 34.2+/-0.09 degrees C in EST-acclimated fish, with FW- and BAY-acclimated fish CTMax at 33.7+/-0.08 and 33.7+/-0.1 degrees C, respectively. Despite the higher CTMax in EST-acclimated fish, FW-acclimated sturgeon ventilation rate reached a peak that was 2 degrees C higher than EST- and BAY-acclimated groups and had a greater range of temperatures within which they exhibited normal ventilatory function as assessed by Q(10) calculation. The osmoregulatory consequences of exposure to near-lethal temperatures were assessed by measuring plasma osmolality and hematocrit, as well as white muscle, brain, and heart tissue water contents. Hematocrit was increased following CTMax exposure, most likely owing to the elevated metabolic demands of temperature increase, and plasma osmolality was significantly increased in EST- and BAY-acclimated fish, which was likely the result of a greater osmotic gradient across the gill as metabolism increased. To our knowledge, this represents the first evidence for an effect of salinity on the upper thermal tolerance of sturgeon, as well as the first investigation of the osmoregulatory consequences of exposure to near-lethal temperatures. J. Exp. Zool. 309A:477-483, 2008. (c) 2008 Wiley-Liss, Inc. 相似文献
8.
Shit F. Chew Yvonne Y. M. Tng Nicklaus L. J. Wee Chia Y. Tok Jonathan M. Wilson Yuen K. Ip 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2010,180(4):511-520
The objective of this study was to elucidate the role of the intestine from juveniles of the marble goby, Oxyeleotris marmorata, during seawater (SW) exposure. It has been reported elsewhere that SW-exposed juvenile O. marmorata exhibits hypoosmotic and hypoionic regulation, with the induction of branchial Na+/K+-ATPase (NKA), Na+:K+:2Cl− cotransporter (NKCC), and cystic fibrosis transmembrane receptor-like chloride channels. Here, we report that SW exposure
also led to significant increases in the activity and protein abundance of NKA in, and probably an increase in Na+ uptake through, its intestine. Additionally, there was an increase in apical NKCC immunoreactivity in the intestinal epithelium,
indicating that there could be increased Cl− uptake through the intestine. These results suggest that absorption of ions, and hence water, from the intestinal lumen could
be an essential part of the osmoregulatory process in juvenile O. marmorata during exposure to SW. Furthermore, there were significant increases in the glutamate content, and the aminating activity and protein abundance
of glutamate dehydrogenase (GDH) in the intestine of fish exposed to SW. Since the intestinal glutamine synthetase activity
and protein abundance decreased significantly, and the intestinal glutamine content remained unchanged, in the SW-exposed
fish, excess glutamate formed via increased GDH activity in the intestine could be channeled to other organs to facilitate
the increased synthesis of amino acids. Taken together, our results indicate for the first time that, besides absorbing ions
and water during SW exposure, the intestine of juvenile O. marmorata also participated in altered nitrogen metabolism in response to salinity changes. 相似文献
9.
Chao-Kai Kang Wen-Kai Yang Shang-Tao Lin Chin-Cheng Liu Huei-Ming Lin Hong-Huan Chen Chien-Wen Cheng Tsung-Han Lee Pung-Pung Hwang 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2013,164(1):181-191
The recent model showed that seawater (SW) mitochondrion-rich (MR) cells with hole-type apical openings secrete Cl? through the transporters including the Na+, K+-ATPase (NKA), Na+, K+, 2Cl? cotransporter (NKCC), and cystic fibrosis transmembrane conductance regulator (CFTR). The present study focused on the dynamic elimination of the Cl? secretory capacity and illustrated different phases (i.e., acute and regulatory phases) of branchial MR cells in response to hypoosmotic challenge. Time-course remodeling of the cell surfaces and the altered expressions of typical ion transporters were observed in the branchial MR cells of SW-acclimated brackish medaka (Oryzias dancena) when exposed to fresh water (FW). On the 1st day post-transfer, rapid changes were shown in the acute phase: the flat-type MR cells with large apical surfaces replaced the hole-type cells, the gene expression of both Odnkcc1a and Odcftr decreased, and the apical immunostaining signals of CFTR protein disappeared. The basolateral immunostaining signals of NKCC1a protein decreased throughout the regulatory phase (> 1 day post-transfer). During this period, the size and number of NKA-immunoreactive MR cells were significantly reduced and elevated, respectively. Branchial NKA expression and activity were maintained at constant levels in both phases. The results revealed that when SW-acclimated brackish medaka were transferred to hypoosmotic FW for 24 h, the Cl? secretory capacity of MR cells was eliminated, whereas NKCC1a protein was retained to maintain the hypoosmoregulatory endurance of the gills. The time-course acute and regulatory phases of gill MR cells showed different strategies of the euryhaline medaka when subjected to hypoosmotic environments. 相似文献
10.
Justin C. Havird Raymond P. Henry Alan E. Wilson 《Comparative biochemistry and physiology. Part D, Genomics & proteomics》2013,8(2):131-140
Recent advances in molecular techniques have allowed gene expression in euryhaline animals to be quantified during salinity transfers. As these investigations transition from studying single genes to utilizing genomics-based methodologies, it is an appropriate time to summarize single gene studies. Therefore, a meta-analysis was performed on 59 published studies that used quantitative polymerase chain reaction (qPCR) to examine expression of osmoregulatory genes (the Na+/K+–ATPase, NKA; the Na+/K+/2Cl? cotransporter, NKCC; carbonic anhydrase, CA; the cystic fibrosis transmembrane regulator, CFTR; and the H+–ATPase, HAT) in response to salinity transfer. Based on 887 calculated effect sizes, NKA, NKCC, CA, and HAT are up-regulated after salinity transfer, while surprisingly, CFTR is unchanged. Meta-analysis also identified influential factors contributing to these changes. For example, expression was highest: 1) during transfers from higher to lower salinities comprising a physiological transition from osmoconformity to osmoregulation, 2) 1–3 days following transfer, 3) during dissimilar transfers, and 4) in crustaceans rather than teleosts. Methodological characteristics (e.g., types of controls) were not important. Experiments lacking in the current literature were also identified. Meta-analyses are powerful tools for quantitatively synthesizing a large body of literature, and this report serves as a template for their application in other areas of comparative physiology. 相似文献
11.
Cheng-Hao Tang Wen-Yi Wu Shu-Chuan Tsai Tatsuki Yoshinaga Tsung-Han Lee 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2010,180(6):813-824
The milkfish (Chanos chanos) is an economic species in Southeast Asia. In Taiwan, the milkfish are commercially cultured in environments of various salinities.
Na+/K+-ATPase (NKA) is a key enzyme for fish iono- and osmoregulation. When compared with gills, NKA and its potential role were
less examined by different approaches in the other osmoregulatory organs (e.g., kidney) of euryhaline teleosts. The objective
of this study was to investigate the correlation between osmoregulatory plasticity and renal NKA in this euryhaline species.
Muscle water contents (MWC), plasma, and urine osmolality, kidney histology, as well as distribution, expression (mRNA and
protein), and specific activity of renal NKA were examined in juvenile milkfish acclimated to fresh water (FW), seawater (SW
35‰), and hypersaline water (HSW 60‰) for at least two weeks before experiments. MWC showed no significant difference among
all groups. Plasma osmolality was maintained within the range of physiological homeostasis in milkfish acclimated to different
salinities, while, urine osmolality of FW-acclimated fish was evidently lower than SW- and HSW-acclimated individuals. The
renal tubules were identified by staining with periodic acid Schiff’s reagent and hematoxylin. Moreover, immunohistochemical
staining showed that NKA was distributed in the epithelial cells of proximal tubules, distal tubules, and collecting tubules,
but not in glomeruli, of milkfish exposed to different ambient salinities. The highest abundance of relative NKA α subunit
mRNA was found in FW-acclimated milkfish rather than SW- and HSW-acclimated individuals. Furthermore, relative protein amounts
of renal NKA α and β subunits as well as NKA-specific activity were also found to be higher in the FW group than SW and the
HSW groups. This study integrated diverse levels (i.e., histological distribution, gene, protein, and specific activity) of
renal NKA expression and illustrated the potential role of NKA in triggering ion reabsorption in kidneys of the marine euryhaline
milkfish when acclimated to a hypotonic FW environment. 相似文献
12.
Microtubule‐dependent changes in morphology and localization of chloride transport proteins in gill mitochondria‐rich cells of the tilapia,Oreochromis mossambicus 下载免费PDF全文
The tilapia (Oreochromis mossambicus) is a euryhaline fish exhibiting adaptive changes in cell size, phenotype, and ionoregulatory functions upon salinity challenge. Na+/Cl? cotransporter (NCC) and Na+/K+/2Cl? cotransporter (NKCC) are localized in the apical and basolateral membranes of mitochondria‐rich (MR) cells of the gills. These cells are responsible for chloride absorption (NCC) and secretion (NKCC), respectively, thus, the switch of gill NCC and NKCC expression is a crucial regulatory mechanism for salinity adaptation in tilapia. However, little is known about the interaction of cytoskeleton and these adaptive changes. In this study, we examined the time‐course of changes in the localization of NKCC/NCC in the gills of tilapia transferred from fresh water (FW) to brackish water (20‰) and from seawater (SW; 35‰) to FW. The results showed that basolateral NKCC disappeared and NCC was expressed in the apical membrane of MR cells. To further clarify the process of these adaptive changes, colchicine, a specific inhibitor of microtubule‐dependent cellular regulating processes was used. SW‐acclimated tilapia were transferred to SW, FW, and FW with colchicine (colchicine‐FW) for 96 h. Compared with the FW‐treatment group, in the MR cells of colchicine‐FW‐treatment group, (1) the average size was significantly larger, (2) only wavy‐convex‐subtype apical surfaces were found, and (3) the basolateral (cytoplasmic) NKCC signals were still exhibited. Taken together, our results suggest that changes in size, phenotype, as well as the expression of NCC and NKCC cotransporters of MR cells in the tilapia are microtubule‐dependent. J. Morphol. 277:1113–1122, 2016. © 2016 Wiley Periodicals, Inc. 相似文献
13.
Brittany D. Kammerer Dietmar Kültz 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(4):535-542
The time-course of programmed cell death (apoptosis) during reorganization of gill epithelium in salinity-stressed tilapia
was analyzed using a recently developed method based on laser scanning cytometry (LSC) of dissociated gill cells. Apoptosis
in mitochondria-rich cells (MRC) was distinguished from that in other cell types using Na+/K+ ATPase (NKA) as a cell-specific marker. Caspase 3/7 activity in MRC, assessed using LSC and microplate assays, increased
significantly starting at 6 h of salinity stress and remained elevated for at least 5 days. This time-course of apoptosis
in MRC during acute salinity stress was reflected in elevated apoptotic DNA fragmentation. In parallel to induction of apoptosis,
MRC showed a pronounced shift to G2 phase of the cell cycle, which is indicative of G2/M cell cycle arrest, and an increase
in NKA abundance per MRC. Unlike in MRC, apoptosis was not significantly increased in other gill cell types, although there
was a small transient increase in DNA fragmentation at 6 h. G2 arrest was also observed. Overall, we interpret our data as
evidence for a significant role of apoptosis in the extensive reorganization of MRC populations that takes place during salinity
acclimation, perhaps similar to its well-established role during organismal development. 相似文献
14.
Jason P. Breves Tetsuya Hirano E. Gordon Grau 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2010,155(3):294-300
This study assessed the endocrine and ionoregulatory responses by tilapia (Oreochromis mossambicus) to disturbances of hydromineral balance during confinement and handling. In fresh water (FW), confinement and handling for 0.5, 1, 2 and 6 h produced elevations in plasma cortisol and glucose; a reduction in plasma osmolality was observed at 6 h. Elevations in plasma prolactins (PRL177 and PRL188) accompanied this fall in osmolality while no effect upon growth hormone (GH) was evident; an increase in insulin-like growth-factor I (IGF-I) occurred at 0.5 h. In seawater (SW), confinement and handling increased plasma osmolality and glucose between 0.5 and 6 h; no effect on plasma cortisol was seen due to variable control levels. Concurrently, both PRLs were reduced in stressed fish with only transient changes in the GH/IGF-I axis. Next, the branchial expression of Na+/K+/2Cl? cotransporter (NKCC) and Na+/Cl? cotransporter (NCC) was characterized following confinement and handling for 6 h. In SW, NKCC mRNA levels increased in stressed fish concurrently with elevated plasma osmolality and diminished gill Na+, K+-ATPase activity; NCC was unchanged in stressed fish irrespective of salinity. Taken together, PRL and NKCC participate in restoring osmotic balance during acute stress while the GH/IGF-I axis displays only modest responses. 相似文献
15.
Joshua PattersonCharlotte Bodinier Christopher Green 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2012,161(4):415-421
The Gulf killifish, Fundulus grandis, is a euryhaline teleost which has important ecological roles in the brackish-water marshes of its native range as well as commercial value as live bait for saltwater anglers. Effects of osmoregulation on growth, survival, and body condition at 0.5, 5.0, 8.0 and 12.0‰ salinity were studied in F. grandis juveniles during a 12-week trial. Relative expression of genes encoding the ion transport proteins Na+/K+-ATPase (NKA), Na+/K+/2Cl− cotransporter(NKCC1), and cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel was analyzed. At 0.5‰, F. grandis showed depressed growth, body condition, and survival relative to higher salinities. NKA relative expression was elevated at 7 days post-transfer but decreased at later time points in fish held at 0.5‰ while other salinities produced no such increase. NKCC1, the isoform associated with expulsion of ions in saltwater, was downregulated from week 1 to week 3 at 0.5‰ while CFTR relative expression produced no significant results across time or salinity. Our results suggest that Gulf killifish have physiological difficulties with osmoregulation at a salinity of 0.5‰ and that this leads to reduced growth performance and survival while salinities in the 5.0-12.0‰ are adequate for normal function. 相似文献
16.
Calvin Fisher Charlotte Bodinier Adam Kuhl Christopher Green 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2013,164(4):572-578
Teleost fish often live in an environment in which osmoregulatory mechanisms are critical for survival and largely unknown in larval fish. The effects of a single important marine ion (K+) on survival and ion regulation of larval Gulf killifish, an estuarine, euryhaline teleost, were determined. A four-week study was completed in four separate recirculating systems with newly hatched larvae. Salinity in all four systems was maintained between 9.5 and 10‰. Two systems were maintained using crystal salt (99.6% NaCl) with K+ supplementation (1.31 ± 0.04 mmol/L and 2.06 ± 0.04 mmol/L K+; mean ± SEM), one was maintained with crystal salt and no K+ supplementation (0.33 ± 0.05 mmol/L K+), the fourth system was maintained using a standard marine mix salt (2.96 ± 0.04 mmol/L K+), the salt mix also included standard ranges of other ions such as calcium and magnesium. Larvae were sampled throughout the experiment for dry mass, Na+/K+-ATPase (NKA) activity, whole body ion composition, relative gene expression (NKA, Na+/K+/2Cl? cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR)), and immunocytochemistry staining for NKA, NKCC, and CFTR. Larvae stocked into water with no K+ supplementation resulted in 100% mortality within 24 h. Mortality and dry mass were significantly influenced by K+ concentration (P ≤ 0.05). No differences were observed among treatment groups for NKA activity. At 1 dph NKA mRNA expression was higher in the 0.3 mmol [K+] group than in other treatment groups and at 7 dph differences in intestinal NKA and CFTR staining were observed. These data indicate that the rearing of larval Gulf killifish may be possible in ion deficient water utilizing specific ion supplementation. 相似文献
17.
Pei-Jen Wang Chia-Hao Lin Lie-Yueh Hwang Chao-Lu Huang Tsung-Han Lee Pung-Pung Hwang 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2009,152(4):544-551
Euryhaline tilapia (Oreochromis mossambicus) survived in brackish water (BW; 20‰) but died in seawater (SW; 35‰) within 6 h when transferred directly from fresh water (FW). The purpose of this study was to clarify responses in gills of FW tilapia to various hyperosmotic shocks induced by BW or SW. In FW-acclimated tilapia, scanning electron micrographs of gills revealed three subtypes of MR cell apical surfaces: wavy-convex (subtype I), shallow-basin (subtype II), and deep-hole (subtype III). Density of apical surfaces of mitochondrion-rich (MR) cell in gills of the BW-transfer tilapia decreased significantly within 3 h post-transfer due to disappearance of subtype I cells, but increased from 48 h post-transfer because of increasing density of subtype III cells. SW-transfer individuals, however, showed decreased density of MR cell openings after 1 h post-transfer because subtype I MR cell disappeared. On the other hand, relative branchial Na+/K+-ATPase (NKA) α1-subunit mRNA levels, protein abundance, and NKA activity of the BW-transfer group increased significantly at 6, 12, and 12 h post-transfer, respectively. In the SW-transfer group, relative mRNA and protein abundance of gill NKA α1-subunit did not change while NKA activity declined before dying in 5 h. Upon SW transfer, dramatic increases (nearly 2-fold) of plasma osmolality, [Na+], and [Cl−] were found prior to death. For the BW-transfer group, plasma osmolality was eventually controlled by 96 h post-transfer by enhancement of NKA expression and subtype III MR cell. The success or failure of NKA activation from gene to functional protein as well as the development of specific SW subtype in gills were crucial for the survival of euryhaline tilapia to various hyperosmotic shocks. 相似文献
18.
Jonusaite S Kelly SP Donini A 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(3):343-352
The physiological response of larval Chironomus riparius was examined following direct transfer from freshwater (FW) to brackish water (BW; 20% seawater). Endpoints of hydromineral
status (hemolymph Na+, Cl−, and K+ levels, hemolymph pH, body water content, and whole body Na+/K+-ATPase and V-type H+-ATPase activity) were examined 1, 3, 5, 12 and 24 h following BW transfer. Larvae transferred from FW to FW served as a control.
Hemolymph Na+ and Cl− levels increased following BW transfer. Hemolymph pH was initially regulated, but significantly decreased after 24 h in BW.
Changes in hemolymph ions were not caused by osmotic loss of water from the hemolymph, since larvae tightly regulated total
body moisture content. Furthermore, salinity did not affect hemolymph K+. When larvae were transferred to BW, Na+/K+-ATPase (NKA) activity did not significantly alter relative to FW control animals. In contrast, V-type H+-ATPase (VA) activity in C. riparius significantly decreased in BW. In FW-reared C. riparius, whole body NKA and VA activities were equivalent. However, in the isolated gut with intact Malpighian tubules of FW-reared
C. riparius, VA activity was significantly greater than whole body while NKA activity was equivalent. This suggested that gut and/or
Malpighian tubule VA activity contributes significantly to whole body VA activity and that a decline in whole body VA activity
in BW may be closely linked to alterations in the physiology of gut and Malpighian tubule tissue. Taken together, data indicate
that VA is important for ion uptake in FW and that the NKA does not play a major role in regulating ion homeostasis when larvae
are acutely exposed to BW. 相似文献
19.
Sardella BA Kültz D Cech JJ Brauner CJ 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2008,178(3):249-256
The Mozambique tilapia (Oreochromis mossambicus) is prone to osmoregulatory disturbances when faced with fluctuating ambient temperatures. To investigate the underlying
causes of this phenomenon, freshwater (FW)- and seawater (SW)-acclimated tilapia were transferred to 15, 25, or 35°C for 2 weeks,
and along with typically used indicators of osmoregulatory status [plasma osmolality and branchial and intestinal specific
Na+, K+-ATPase (NKA) activity], we used tissue microarrays (TMA) and laser-scanning cytometry (LSC) to characterize the effects of
temperature acclimation. Tissue microarrays were stained with fluorescently labeled anti-Na+, K+-ATPase antibodies that allowed for the quantification of NKA abundance per unit area within individual branchial mitochondria-rich
cells (MRCs) as well as sections of renal tissue. Mitochondria-rich cell counts and estimates of size were carried out for
each treatment by the detection of DASPMI fluorescence. The combined analyses showed that SW fish have larger but fewer MRCs
that contain more NKA per unit area. After a 2-week acclimation to 15°C tilapia experienced osmotic imbalances in both FW
and SW that were likely due to low NKA activity. SW-acclimated fish compensated for the low activity by increasing MRC size
and subsequently the concentration of NKA within MRCs. Although there were no signs of osmotic stress in FW-acclimated tilapia
at 25°C, there was an increased NKA capacity that was most likely mediated by a higher MRC count. We conclude on the basis
of the different responses to temperature acclimation that salinity-induced changes in the NKA concentration of MRCs alter
thermal tolerance limits of tilapia. 相似文献
20.
Allen PJ McEnroe M Forostyan T Cole S Nicholl MM Hodge B Cech JJ 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(8):1045-1062
We measured the ontogeny of salinity tolerance and the preparatory hypo-osmoregulatory physiological changes for seawater
entry in green sturgeon (Acipenser medirostris), an anadromous species occurring along the Pacific Coast of North America. Salinity tolerance was measured every 2 weeks
starting in 40-day post-hatch (dph) juveniles and was repeated until 100% survival at 34‰ was achieved. Fish were subjected
to step increases in salinity (5‰ 12 h−1) that culminated in a 72-h exposure to a target salinity, and treatment groups (0, 15, 20, 25, 30, 34‰; and abrupt exposure
to 34‰) were adjusted as fish developed. After 100% survival was achieved (134 dph), a second experiment tested two sizes
of fish for 28-day seawater (33‰) tolerance, and gill and gastrointestinal tract tissues were sampled. Their salinity tolerance
increased and plasma osmolality decreased with increasing size and age, and electron microscopy revealed three types of mitochondria-rich
cells: one in fresh water and two in seawater. In addition, fish held on a natural photoperiod in fresh water at 19°C showed
peaks in cortisol, thyroid hormones and gill and pyloric ceca Na+, K+-ATPase activities at body sizes associated with seawater tolerance. Therefore, salinity tolerance in green sturgeon increases
during ontogeny (e.g., as these juveniles may move down estuaries to the ocean) with increases in body size. Also, physiological
and morphological changes associated with seawater readiness increased in freshwater-reared juveniles and peaked at their
seawater-tolerant ages and body sizes. Their seawater-ready body size also matched that described for swimming performance
decreases, presumably associated with downstream movements. Therefore, juvenile green sturgeon develop structures and physiological
changes appropriate for seawater entry while growing in fresh water, indicating that hypo-osmoregulatory changes may proceed
by multiple routes in sturgeons. 相似文献