The loss of hyperosmoregulatory ability in migrating juvenile American shad, Alosa sapidissima

1997 ◽  
Vol 54 (10) ◽  
pp. 2377-2387 ◽  
Author(s):  
J Zydlewski ◽  
S D McCormick
Keyword(s):  
Atpase Activity ◽  
Fresh Water ◽  
Condition Factor ◽  
Fold Increase ◽  
American Shad ◽  
Physiological Changes ◽  
Laboratory Studies ◽  
Alosa Sapidissima ◽  
Plasma Chloride ◽  
Natural Temperature

Investigations on juvenile American shad (Alosa sapidissima) revealed several physiological changes associated with downstream migration. Plasma chloride decreased 20% in wild juvenile shad during the autumn migration. Migrants had lower condition factor and hematocrit than non-migrant shad captured by beach seining. Gill Na + ,K + -ATPase activity of migrant shad was higher than non-migrant; a 2.5-fold increase was observed in 1993, while a 57% increase was observed in 1994. Similar changes were observed in laboratory studies of shad maintained in fresh water under simulated natural temperature and photoperiod. Plasma chloride dropped 68% and gill Na + ,K + -ATPase activity increased 3-fold over a 3-month period. Decreased plasma chloride was associated with increased mortality. Increases in gill Na + ,K + -ATPase activity decreases in plasma chloride and osmolality, and incidence of mortality were delayed and moderated, but not eliminated, in shad maintained at constant temperature (24°C). Shad did not survive in fresh water past December regardless of temperature regime. In seawater, all shad survived and showed no perturbation of plasma chloride at 24°C or simulated natural temperature (above 4°C). The decline in hyperosmoregulatory ability, as influenced by declining temperatures, may serve as a proximate cue for autumnal migration.

scholarly journals The ontogeny of salinity tolerance in the American shad, Alosa sapidissima

1997 ◽  
Vol 54 (1) ◽  
pp. 182-189 ◽  
Author(s):  
J Zydlewski ◽  
S D McCormick
Keyword(s):  
Atpase Activity ◽  
Salinity Tolerance ◽  
American Shad ◽  
Plasma Sodium ◽  
Term Survival ◽  
Alosa Sapidissima ◽  
Seawater Tolerance ◽  
Plasma Chloride ◽  
Survival And Growth

Larval and juvenile American shad (Alosa sapidissima) raised from eggs in the laboratory were subjected to biweekly 24-h seawater (35 ppt) challenges. There was no survival in seawater before 36 days post-hatch, and most mortalities occurred within 2 h of transfer. Twenty-four hour survival reached 89% in seawater at 45 days post-hatch (when larval-juvenile metamorphosis occurred), 96% at 58 days post-hatch, and 92-100% from 58 to 127 days post-hatch. Survival in seawater for 24 h was a good indicator of long-term survival and growth. Seawater tolerance was associated with gill development and increased gill Na + ,K + -ATPase activity, which occurred at the onset of the larval-juvenile metamorphosis (3 months prior to the peak of migration). Gill Na + ,K + -ATPase activity increased threefold in juvenile shad acclimated to 35-ppt seawater, reached peak levels 5 days after transfer, and remained elevated with respect to controls. Plasma sodium and chloride increased 12 and 11%, respectively, within 48 h of seawater exposure. Plasma sodium recovered to initial levels and plasma chloride stabilized at a level 10% higher than initial levels after 5 days. Ionic perturbations that occurred at elevated salinities stabilized when gill Na + ,K + -ATPase activity increased.

Physiological Changes during Seaward Migration of Wild Juvenile Coho Salmon (Oncorhynchus kisutch)

1987 ◽  
Vol 44 (2) ◽  
pp. 452-457 ◽  
Author(s):  
Jeffrey D. Rodgers ◽  
Richard D. Ewing ◽  
James D. Hall
Keyword(s):  
Atpase Activity ◽  
Coho Salmon ◽  
Condition Factor ◽  
Specific Activity ◽  
Oncorhynchus Kisutch ◽  
Physiological Changes ◽  
Fish Gill ◽  
Seaward Migration ◽  
Cyclic Changes

Peaks in migration of wild juvenile coho salmon (Oncorhynchus kisutch) from Knowles Creek (Siuslaw River, Oregon) occurred in November and May. Condition factor of nonmigrant fish was higher than migrants or captives throughout the study. Skin guanine levels of migrant fish rose sharply during the first 2 wk of April and continued to rise through June. Gill (Na + K)-ATPase specific activity of migrants rose gradually from a low in January to a maximum in June. Gill (Na + K)-ATPase activity of migrants and nonmigrants was low and not significantly different during November to mid-March. During April, however, gill ATPase activity of migrants rose to become significantly higher than that of nonmigrants until the first 2 wk of May. Cyclic changes in gill (Na + K)-ATPase activity was not observed in these fish. Gill (Na + K)-ATPase activity of fish reared in a laboratory was similar to that of wild nonmigrants until it peaked during the last 2 wk of April, after which the specific activity was lower than either migrants or nonmigrants.

The Behavior of Adult American Shad (Alosa sapidissima) During Migration from Salt to Fresh Water as Observed by Ultrasonic Tracking Techniques

1972 ◽  
Vol 29 (10) ◽  
pp. 1445-1449 ◽  
Author(s):  
Julian J. Dodson ◽  
William C. Leggett ◽  
Robert A. Jones
Keyword(s):  
Fresh Water ◽  
Behavior Pattern ◽  
Salt Water ◽  
Leading Edge ◽  
American Shad ◽  
Physiological Adaptation ◽  
Connecticut River ◽  
Alosa Sapidissima ◽  
Discharge Rates ◽  
Ultrasonic Tracking

Five of seven adult American shad (Alosa sapidissima), tracked continuously with ultrasonic transmitters in the lower estuary of the Connecticut River in 1968 during their spawning migration to fresh water, exhibited extensive meandering, ranging 24–53 hr in duration in the region of the saltwater–freshwater interface. The salinity in the Connecticut River is like a wedge; its daily position is dependent on upland discharge, and its hourly position is dependent on tidal activity. The fish were observed during all tidal conditions and at several discharge rates, and in all cases they remained near the leading edge of salt water during the meandering phase. This behavior pattern was not a result of handling nor was it a typical behavioral response to tidal cycle. It was concluded that the meandering observed in the region of the saltwater–freshwater interface was due to physiological adaptation of the fish to fresh water. Of the remaining two shad tagged, one proceeded directly upstream without meandering, and one moved downstream.

scholarly journals Temperature effects on sodium pump phosphoenzyme distribution in human red blood cells.

1985 ◽  
Vol 85 (1) ◽  
pp. 123-136 ◽  
Author(s):  
J H Kaplan ◽  
L J Kenney
Keyword(s):  
Atpase Activity ◽  
Cell Membranes ◽  
Conformational Transition ◽  
Fold Increase ◽  
Inhibitory Effect ◽  
Red Cell ◽  
Na Pump ◽  
Na Ions ◽  
Red Cell Membranes ◽  
Increasing Temperature

Phosphorylation of red cell membranes at ambient temperatures with micromolar [32P]ATP in the presence of Na ions produced phosphoenzyme that was dephosphorylated rapidly upon the addition of ADP or K ions. However, as first observed by Blostein (1968, J. Biol. Chem., 243:1957), the phosphoenzyme formed at 0 degrees C under otherwise identical conditions was insensitive to the addition of K ions but was dephosphorylated rapidly by ADP. This suggested that the conformational transition from ADP-sensitive, K-insensitive Na pump phosphoenzyme (E1 approximately P) to K-sensitive, ADP-insensitive phosphoenzyme (E2P) is blocked at 0 degrees C. Since the ATP:ADP exchange reaction is a partial reaction of the overall enzyme cycle dependent upon the steady state level of E1 approximately P that is regulated by [Na], we examined the effects of temperature on the curve relating [Na] to ouabain-sensitive ATP:ADP exchange. The characteristic triphasic curve seen at higher temperatures when [Na] was between 0.5 and 100 mM was not obtained at 0 degrees C. Simple saturation was observed instead with a K0.5 for Na of approximately 1 mM. The effect of increasing temperature on the ATP:ADP exchange at fixed (150 mM) Na was compared with the effect of increasing temperature on (Na + K)-ATPase activity of the same membrane preparation. It was observed that (a) at 0 degrees C, there was significant ouabain-sensitive ATP:ADP exchange activity, (b) at 0 degrees C, ouabain-sensitive (Na + K)-ATPase activity was virtually absent, and (c) in the temperature range 5-37 degrees C, there was an approximately 300-fold increase in (Na + K)-ATPase activity with only a 9-fold increase in the ATP:ADP exchange. These observations are in keeping with the suggestion that the E1 approximately P----E2P transition of the Na pump in human red cell membranes is blocked at 0 degrees C. Previous work has shown that the inhibitory effect of Na ions and the low-affinity stimulation by Na of the rate of ATP:ADP exchange occur at the extracellular surface of the Na pump. The absence of both of these effects at 0 degrees C, where E1 approximately P is maximal, supports the idea that external Na acts through sites on the E2P form of the phosphoenzyme.

scholarly journals Dietary sodium requirement determined for juvenile hybrid tilapia (Oreochromis niloticus × O. aureus) reared in fresh water and seawater

2004 ◽  
Vol 91 (4) ◽  
pp. 585-590 ◽  
Author(s):  
Shi-Yen Shiau ◽  
Li-Shan Lu
Keyword(s):  
Weight Gain ◽  
Atpase Activity ◽  
Fresh Water ◽  
Oreochromis Niloticus ◽  
Polynomial Regression ◽  
Control Diet ◽  
Dietary Treatment ◽  
Basal Diet ◽  
Dietary Sodium ◽  
Whole Body

Two 8-week feeding trials were conducted to determine the dietary Na requirement for juvenile hybrid tilapia (Oreochromis niloticus × O. aureus) reared in fresh water and seawater. In each experiment, NaCl was added to the basal diet at 0, 0·5, 1, 2, 3, 5, or 7g Na/kg diet (fresh water) and at 0, 0·2, 0·5, 0·8, 1·2, 1·5, 2, or 3g Na/kg diet (seawater). Each diet was fed to three replicate groups of fish, individual fish initially weighing 0·69 (se 0·01) g, in a closed, recirculating rearing system. In fresh water, the tilapia fed the diet supplemented with 2g Na/kg diet had significantly (P<0·05) greater weight gain than the fish fed the diets supplemented with ≥3 and ≤0·5g Na/kg diet. Feed efficiency (FE) in fish generally followed the weight-gain pattern. Gill Na+–K+ ATPase activity was highest in the fish fed the diets supplemented with 1–3g Na/kg diet, followed by the fish fed the diet with 7g Na/kg diet and lowest in the fish fed the unsupplemented control diet. In seawater, the weight gain, FE and gill Na+–K+ ATPase activity in fish were not affected by the dietary treatment. Analysis by polynomial regression of weight gain, by broken-line regression of gill Na+–K+ ATPase activity and by linear regression of whole-body Na retention of the fish reared in fresh water, indicated that the adequate dietary Na concentration for tilapia is about 1·5g/kg diet. The present study also suggests that no dietary Na is required for tilapia reared in seawater.

scholarly journals Dynamic regulation of extracellular ATP in Escherichia coli

2017 ◽  
Vol 474 (8) ◽  
pp. 1395-1416 ◽  
Author(s):  
Cora Lilia Alvarez ◽  
Gerardo Corradi ◽  
Natalia Lauri ◽  
Irene Marginedas-Freixa ◽  
María Florencia Leal Denis ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Atpase Activity ◽  
Atp Release ◽  
Membrane Vesicles ◽  
Fold Increase ◽  
Extracellular Atp ◽  
Outer Membrane Vesicles ◽  
Dynamic Regulation ◽  
E Coli

We studied the kinetics of extracellular ATP (ATPe) in Escherichia coli and their outer membrane vesicles (OMVs) stimulated with amphipatic peptides melittin (MEL) and mastoparan 7 (MST7). Real-time luminometry was used to measure ATPe kinetics, ATP release, and ATPase activity. The latter was also determined by following [32P]Pi released from [γ-32P]ATP. E. coli was studied alone, co-incubated with Caco-2 cells, or in rat jejunum segments. In E. coli, the addition of [γ-32P]ATP led to the uptake and subsequent hydrolysis of ATPe. Exposure to peptides caused an acute 3-fold (MST7) and 7-fold (MEL) increase in [ATPe]. In OMVs, ATPase activity increased linearly with [ATPe] (0.1–1 µM). Exposure to MST7 and MEL enhanced ATP release by 3–7 fold, with similar kinetics to that of bacteria. In Caco-2 cells, the addition of ATP to the apical domain led to a steep [ATPe] increase to a maximum, with subsequent ATPase activity. The addition of bacterial suspensions led to a 6–7 fold increase in [ATPe], followed by an acute decrease. In perfused jejunum segments, exposure to E. coli increased luminal ATP 2 fold. ATPe regulation of E. coli depends on the balance between ATPase activity and ATP release. This balance can be altered by OMVs, which display their own capacity to regulate ATPe. E. coli can activate ATP release from Caco-2 cells and intestinal segments, a response which in vivo might lead to intestinal release of ATP from the gut lumen.

scholarly journals Evasive responses of American shad (Alosa sapidissima) to ultrasonic stimuli

2003 ◽  
Vol 4 (2) ◽  
pp. 25-30 ◽  
Author(s):  
Dennis T. T. Plachta ◽  
Arthur N. Popper
Keyword(s):  
American Shad ◽  
Alosa Sapidissima

Role of sarcoplasmic reticulum in loss of load-sensitive relaxation in pressure overload cardiac hypertrophy

1994 ◽  
Vol 266 (1) ◽  
pp. H68-H78 ◽  
Author(s):  
C. R. Cory ◽  
R. W. Grange ◽  
M. E. Houston
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Cardiac Hypertrophy ◽  
Atpase Activity ◽  
Pressure Overload ◽  
Fold Increase ◽  
Left Ventricular ◽  
Isometric Tension ◽  
Tension Development ◽  
Sequestration Potential

The loss of load-sensitive relaxation observed in the pressure-overloaded heart may reflect a strategy of slowed cytosolic Ca2+ uptake to yield a prolongation of the active state of the muscle and a decrease in cellular energy expenditure. A decrease in the potential of the sarcoplasmic reticulum (SR) to resequester cytosolic Ca2+ during diastole could contribute to this attenuated load sensitivity. To test this hypothesis, both in vitro mechanical function of anterior papillary muscles and the SR Ca2+ sequestration potential of female guinea pig left ventricle were compared in cardiac hypertrophy (Hyp) and sham-operated (Sham) groups. Twenty-one days of pressure overload induced by coarctation of the suprarenal, subdiaphragmatic aorta resulted in a 36% increase in left ventricular mass in the Hyp. Peak isometric tension, the rate of isometric tension development, and the maximal rates of isometric and isotonic relaxation were significantly reduced in Hyp. Load-sensitive relaxation were significantly reduced in Hyp. Load-sensitive relaxation quantified by the ratio of a rapid loading to unloading force step in isotonically contracting papillary muscle was reduced 50% in Hyp muscles. Maximum activity of SR Ca(2+)-adenosinetriphosphatase (ATPase) measured under optimal conditions (37 degrees C; saturating Ca2+) was unaltered, but at low free Ca2+ concentrations (0.65 microM), it was decreased by 43% of the Sham response. Bivariate regression analysis revealed a significant (r = 0.84; P = 0.009) relationship between the decrease in SR Ca(2+)-ATPase activity and the loss of load-sensitive relaxation after aortic coarctation. Stimulation of the SR Ca(2+)-ATPase by the catalytic subunit of adenosine 3',5'-cyclic monophosphate-dependent protein kinase resulted in a 2.6-fold increase for Sham but only a 1.6-fold increase for Hyp. Semiquantitative Western blot radioimmunoassays revealed that the changes in SR Ca(2+)-ATPase activity were not due to decreases in the content of the Ca(2+)-ATPase protein or phospholamban. Our data directly implicate a role for decreased SR function in attenuated load sensitivity. A purposeful downregulation of SR Ca2+ uptake likely results from a qualitative rather than a quantitative change in the ATPase and possibly one of its key regulators, phospholamban.

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