The effect of aluminum in soft water at low pH on oxygen consumption by the dragonfly Libellula julia Uhler

Hydrobiologia ◽  
1990 ◽  
Vol 190 (1) ◽  
pp. 55-59 ◽  
Author(s):  
John P. Rockwood ◽  
Daniel S. Jones ◽  
Robert A. Coler
Keyword(s):  
Oxygen Consumption ◽  
Low Ph ◽  
Soft Water

scholarly journals Oxidation of monohydric phenol substrates by tyrosinase. An oximetric study

1992 ◽  
Vol 288 (1) ◽  
pp. 63-67 ◽  
Author(s):  
S Naish-Byfield ◽  
P A Riley
Keyword(s):  
Oxygen Consumption ◽  
Maximum Rate ◽  
Low Ph ◽  
Molar Ratio ◽  
Lag Phase ◽  
Complete Oxidation ◽  
Mushroom Tyrosinase ◽  
Tyrosine Oxidation ◽  
Rate Of Reaction ◽  
Dopa Oxidase

The purity of commercially available mushroom tyrosinase was investigated by non-denaturing PAGE. Most of the protein in the preparation migrated as a single band under these conditions. This band contained both tyrosinase and dopa oxidase activity. No other activity of either classification was found in the preparation. Oxygen consumption by tyrosinase during oxidation of the monohydric phenol substrates tyrosine and 4-hydroxyanisole (4HA) was monitored by oximetry in order to determine the stoichiometry of the reactions. For complete oxidation, the molar ratio of oxygen: 4HA was 1:1. Under identical conditions, oxidation of tyrosine required 1.5 mol of oxygen/mol of tyrosine. The additional oxygen uptake during tyrosine oxidation is due to the internal cyclization of dopaquinone to form cyclodopa, which undergoes a redox reaction with dopaquinone to form dopachrome and dopa, which is then oxidized by the enzyme, leading to an additional 0.5 mol of oxygen/mol of original substrate. Oxygen consumption for complete oxidation of 200 nmol of 4HA was constant over a range of concentrations of tyrosinase of 33-330 units/ml of substrate. The maximum rate of reaction was directly proportional to the concentration of tyrosinase, whereas the length of the lag phase decreased non-linearly with increasing tyrosinase concentration. Activation of the enzyme by exposure to citrate was not seen, nor was the lag phase abolished by exposure of the enzyme to low pH. Michaelis-Menten analysis of tyrosinase in which the lag phase is abolished by pre-exposure of the enzyme to a low concentration of dithiothreitol gave Km values for tyrosine and 4HA of 153 and 20 microM respectively.

scholarly journals Effects of oxygen tension and pH on the respiratory burst of human neutrophils

Blood ◽  
1979 ◽  
Vol 53 (6) ◽  
pp. 1133-1139 ◽  
Author(s):  
TG Gabig ◽  
SI Bearman ◽  
BM Babior
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Concentration ◽  
Respiratory Burst ◽  
Low Ph ◽  
Human Neutrophils ◽  
Respiratory Burst Activity ◽  
Similar Dependence ◽  
Activated Neutrophils ◽  
Acidic Conditions ◽  
O2 Production

Abstract The respiratory burst of human neutrophils was measured under conditions of hypoxia and low pH. O2 -- production by neutrophils activated with opsonized zymosan fell slowly as the oxygen concentration declined to 1%, then dropped more sharply, reaching negligible levels at oxygen concentrations less than 0.25%. Production was half maximal at an oxygen concentration of 0.35% (equivalent to approximately 10-microM dissolved oxygen). O2- production by the cell- free O2- -forming system prepared from zymosan-activated neutrophils showed a similar dependence on oxygen concentration. A drop in pH caused decreases in both oxygen consumption and O2-- production by zymosan-treated neutrophils, values at PH 6.0 being 10%--20% of those observed at pH 7.5. Experiments with the cell-free O2-- -forming system suggested that this decline in respiratory burst activity at low pH was due to inefficient activation of the O2-- -forming enzyme under acidic conditions.

Effects of Acid Water and Aluminum on Parr–Smolt Transformation and Seawater Tolerance in Atlantic Salmon, Salmo salar

1993 ◽  
Vol 50 (9) ◽  
pp. 1816-1827 ◽  
Author(s):  
Magne Staurnes ◽  
Per Blix ◽  
Ola B. Reite
Keyword(s):  
Carbonic Anhydrase ◽  
Atlantic Salmon ◽  
Atpase Activity ◽  
Salmo Salar ◽  
Carbonic Anhydrase Activity ◽  
Low Ph ◽  
Soft Water ◽  
Control Fish ◽  
Exposed Fish ◽  
Seawater Tolerance

Smolting Atlantic salmon, Salmo salar, were kept from 11 April to 24 May in soft water of pH 5 or in soft water of pH 5 and 50 μg aluminum (Al)∙L−1. Control fish were kept in soft water of pH 6.3–6.5. Water temperature was 8–14 °C. In mid-May, some of the control smolts were transferred to the test conditions for 8 d. Exposure to acid water resulted in osmoregulatory failure and high mortality rate. Al strongly enhanced toxicity. Sensitivity to low pH or low pH/Al exposure greatly increased when fish had developed to seawater tolerant smolts. In control and acid-exposed fish, gill carbonic anhydrase activity remained unchanged throughout the experiment whereas in Al-exposed fish, carbonic anhydrase activity decreased. Gill Na+K+-ATPase activity in control fish peaked in mid-May simulanteously with development of seawater tolerance. Fish from both acid-exposed groups had low seawater tolerance. Na+,K+-ATPase activity declined to 60% of start value in acid-exposed fish and to parr level in Al-exposed fish. Hypoosmoregulatory ability was linearly correlated with gill Na+K+-ATPase activity. Reduction in plasma Na+ concentration in acid-exposed fish was linearly correlated with the reduction in gill Na+,K+-ATPase activity.

scholarly journals Responses of an Amazonian Teleost, the Tambaqui (Colossoma macropomum), to Low pH in Extremely Soft Water

1998 ◽  
Vol 71 (6) ◽  
pp. 658-670 ◽  
Author(s):  
Chris M. Wood ◽  
Rod W. Wilson ◽  
Richard J. Gonzalez ◽  
Marjorie L. Patrick ◽  
Harold L. Bergman ◽  
...  
Keyword(s):  
Low Ph ◽  
Soft Water ◽  
Colossoma Macropomum

The Influence of Calcium on the Physiological Responses of the Rainbow Trout, Salmo Gairdneri, to Low Environmental pH

1980 ◽  
Vol 88 (1) ◽  
pp. 109-132
Author(s):  
D. G. McDONALD ◽  
H. HŌBE ◽  
C. M. WOOD
Keyword(s):  
Rainbow Trout ◽  
Calcium Concentration ◽  
Physiological Responses ◽  
Hard Water ◽  
Low Ph ◽  
Soft Water ◽  
Salmo Gairdneri ◽  
Minor Depression ◽  
Regulatory Failure ◽  
A Minor

The physiological responses of 1- to 2-year-old rainbow trout to low pH are dependent on the environmental calcium concentration. Trout, maintained for 5 days in moderately hard water ([Ca2+] = 1·6–2·7 m-equiv/1) at a mean pH of 4·3, developed a major blood acidosis but exhibited only a minor depression in plasma ion levels. In acidified soft water ([Ca2+] = 0·3 m-equiv/1), only a minor acidosis occurred, but plasma ion levels fell and there were substantially greater mortalities. Lethal bioassays performed on fingerling trout over a range of pH levels (3·0–4·8) revealed an important influence of external [Ca2+] on resistance to acid exposure. Terminal physiological measurements on adult fish succumbing to low pH in soft water indicate the singular importance of iono-regulatory failure as the toxic mechanism of action under these circumstances.

Hatching Success of Mayfly Eggs at Low pH

1988 ◽  
Vol 45 (9) ◽  
pp. 1649-1652 ◽  
Author(s):  
Locke Rowe ◽  
Jeffrey Hudson ◽  
Michael Berrill
Keyword(s):  
Hatching Success ◽  
Low Ph ◽  
Soft Water ◽  
The Other ◽  
Hatching Rate ◽  
Field Surveys ◽  
Acid Sensitivity ◽  
Significant Mortality

Eggs of the mayflies Leptophlebia cupida, Habrophlebia vibrans, Stenonema femoratum, and Baetis flavistriga were reared in soft water at several pH levels (4.0, 4.5, 5.0, and 6.5) in the laboratory. The proportion of eggs undergoing eclosion did not vary with pH. However, in B. flavistriga, significant mortality of nymphs occurred before the hatch was complete at pH 4.0 (91%) and 4.5 (12%). Hatching rate of H. vibrans was significantly retarded at pH 4.0, 4.5, and especially at pH 5.0, but was unaffected in the other three species. The effects of elevated [H+] on these species are in agreement with their relative acid sensitivity inferred from field surveys.

Effect of low pH on sodium regulation in two species of Daphnia

1984 ◽  
Vol 62 (10) ◽  
pp. 1965-1970 ◽  
Author(s):  
Magda Havas ◽  
Thomas C. Hutchinson ◽  
Gene E. Likens
Keyword(s):  
Daphnia Magna ◽  
Hard Water ◽  
Low Ph ◽  
Soft Water ◽  
Sodium Influx ◽  
Daphnia Middendorffiana ◽  
Sodium Loss ◽  
Sodium Regulation

The effect of low pH on sodium-22 influx and outflux of Daphnia magna and Daphnia middendorffiana was assessed. Experiments were conducted in both hard and soft water with experimental pHs ranging from 3.5 to 8.0. In hard water, at and below pH 4.0, there was a net loss of sodium from both species. The rate of sodium loss (outflux) increased significantly, while the rate of uptake (influx) remained constant at pH 4.0 compared with the reference pH 8.0. Only at extremely low pH (pH 3.5) was sodium influx inhibited in hard water. In soft water, D. magna responded quite differently. Sodium influx was inhibited by 23% at pH 5.0 and by 69% at pH 4.5 compared with the control (pH 6.5). Sodium outflux was stimulated to 125% of the control at pH 4.5. The net loss of sodium in soft water was due to both an increase in sodium outflux and a decrease in sodium influx, while in hard water the effect was primarily on sodium outflux. Daphnia magna and D. middendorffiana have problems with sodium regulation below pH 5.5 in soft water and below pH 4.5 in hard water, which indicates that they are considerably more sensitive to low pH in soft water than in hard water.

Variation in tolerance to low environmental pH by the crayfish Orconectes rusticus, O. propinquus, and Cambarus robustus

1985 ◽  
Vol 63 (11) ◽  
pp. 2586-2589 ◽  
Author(s):  
Michael Berrill ◽  
Lois Hollett ◽  
Arlene Margosian ◽  
Jeff Hudson
Keyword(s):  
Life Cycle ◽  
Laboratory Experiments ◽  
Low Ph ◽  
Soft Water ◽  
Stage Iii ◽  
Aluminum Concentration ◽  
Orconectes Rusticus ◽  
Juvenile Stages ◽  
Ph Range ◽  
Crayfish Species

We compared the tolerance of three common Ontario crayfish species to low pH under natural and laboratory conditions in water varying in aluminum concentration and hardness. Both transplant and laboratory experiments indicated that exposure to a pH range of 5.4–6.1 in soft water was toxic to attached juvenile stages of Orconectes rusticus and O. propinquus but not to females carrying the broods. In contrast, stage III juveniles of Cambarus robustus molted and survived in soft water at pH 4. Cambarus robustus is clearly far less sensitive to low pH stress than the two Orconectes species. No increased mortality due to the presence of elevated aluminum occurred among stage III juveniles of the three species exposed to pH 4.5–5.0 in soft water. Physiological differences, augmented by differences in life cycle, may account for the continued presence of C. robustus in acid-stressed lakes and streams.

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