Effects of Aluminum and Low pH on Net Ion Fluxes and Ion Balance in the Brook Trout (Salvelinus fontinalis)

1988 ◽  
Vol 45 (9) ◽  
pp. 1563-1574 ◽  
Author(s):  
C. E. Booth ◽  
D. G. McDonald ◽  
B. P. Simons ◽  
C. M. Wood
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Inhibitory Effect ◽  
Low Ph ◽  
Exposed Fish ◽  
Water Ph ◽  
In The Wild ◽  
Ph Dependent ◽  
Total Body ◽  
Stimulation Of

Adult brook trout (Salvelinus fontinalis) were exposed for up to 11 d to one of a matrix of 18 Al, low pH, and Ca2+ combinations, chosen as representive of acidified softwater environments in the wild. Reduction in water pH led to pH-dependent net losses of Na+ and Cl− exacerbated by the presence of Al in the water and reduced by elevating Ca2+. Any animal losing more than 4% of its total body Na+ over the first 24 h of Al exposure had a greater than 90% likelihood of eventual mortality. Na+ losses arose from inhibition of influx and stimulation of efflux. The inhibition was persistent and pH dependent. Addition of Al to acidified water had a slight further inhibitory effect on Na+ influx and a large stimulatory effect on efflux. The latter was dependent on Al concentration, was the main cause of initial ion losses and mortality, and declined with time in surviving animals. All Al-exposed fish accumulated Al on their gills, but this was apparently mainly surface or subsurface bound, since no internal Al (plasma or liver) could be detected. Nonsurviving fish had substantially higher gill Al levels than survivors.

Retardation and Recovery of Growth in Brook Trout Fry (Salvelinus fontinalis) Exposed for Various Durations to Acidified Water

1986 ◽  
Vol 43 (10) ◽  
pp. 2048-2050 ◽  
Author(s):  
W. H. Tam ◽  
P. D. Payson ◽  
R. J. J. Roy
Keyword(s):  
Growth Inhibition ◽  
Growth Rates ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Low Ph ◽  
Fish Growth ◽  
Control Fish ◽  
Treated Fish ◽  
Test Fish ◽  
Neutral Water

Brook trout fry (Salvelinus fontinalis) were exposed to pH 4.66 for various durations up to 141 d and then returned to neutral water. Growth of test fish was in general significantly lower than that of control fish for exposures up to days 45–78. In four of six groups of acid-treated fish, growth eventually recovered and the growth rates were not different from that of control fish. The results suggested that growth inhibition was induced early in the exposure to sublethally low pH and that recovery in the latter phase of the experiment occurred whether pH remained acidic or was readjusted to neutral.

Growth and Resistance to Stress in Brook Trout Fed Sublethal Levels of DDT

1968 ◽  
Vol 25 (11) ◽  
pp. 2443-2451 ◽  
Author(s):  
Kenneth J. Macek
Keyword(s):  
Weight Gain ◽  
Water Temperature ◽  
Brook Trout ◽  
Feeding Rate ◽  
Salvelinus Fontinalis ◽  
Physiological Stress ◽  
Environmental Stresses ◽  
Exposed Fish ◽  
Cumulative Mortality ◽  
Resistance To Stress

When underyearling brook trout (Salvelinus fontinalis) were fed DDT at a rate of 2.0 mg/kg per week for 31 weeks, they exhibited greater weight gain (43.2 ± 0.8 g) during the period than did untreated fish (36.6 ± 1.1 g). When underyearling fish were fed DDT at different rates for 26 weeks and then starved or fed at a rate equivalent to 10% of the usual feeding rate, the cumulative mortality during this period was 96.2% among fish exposed to 3.0 mg/kg per week, 88.6% among fish exposed to 2.0 mg/kg per week, and 1.2% among untreated fish. Differences in the length of survival of DDT-exposed fish occurred due to dosage, sex, and type of starvation. The evidence suggests that the mortality of DDT-exposed fish was due to the interaction of DDT residues with a combination of environmental stresses, namely starvation, decreasing water temperature, and possibly the physiological stress associated with the spawning season.

scholarly journals The active repertoire of Escherichia coli peptidoglycan amidases varies with physiochemical environment

2020 ◽  
Author(s):  
Elizabeth A. Mueller ◽  
Abbygail G. Iken ◽  
Mehmet Ali Öztürk ◽  
Mirko Schmitz ◽  
Barbara Di Ventura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Cell Separation ◽  
Antimicrobial Agents ◽  
Model Organism ◽  
Growth Conditions ◽  
Low Ph ◽  
E Coli ◽  
Ph Dependent ◽  
Stimulation Of

ABSTRACTNearly all bacteria are encased in a peptidoglycan cell wall, an essential crosslinked matrix of polysaccharide strands and short peptide stems. In the Gram-negative model organism Escherichia coli, more than forty cell wall synthases and autolysins coordinate the growth and division of the peptidoglycan sacculus in the periplasm. The precise contribution of many of these enzymes to cell wall metabolism remains unclear due to significant apparent redundancy, particularly among the cell wall autolysins. E. coli produces three major LytC-type-N-acetylmuramoyl-L-alanine amidases, which share a role in separating the newly formed daughter cells during cytokinesis. Here, we reveal two of the three amidases exhibit growth medium-dependent changes in activity. Specifically, we report acidic growth conditions stimulate AmiB—and to a lesser extent, AmiC—activity. Combining computational and genetic analysis, we demonstrate that low pH-dependent stimulation of AmiB requires three periplasmic amidase activators: EnvC, NlpD, and YgeR. Altogether, our findings support overlapping, but not redundant, roles for the E. coli amidases in cell separation and illuminate the physiochemical environment as an important mediator of cell wall enzyme activity.IMPORTANCEPenicillin and related β-lactam antibiotics targeting the bacterial cell wall synthesis are among the most commonly prescribed antimicrobials worldwide. However, rising rates of antibiotic resistance and tolerance jeopardize their continued clinical use. Development of new cell wall active therapeutics, including those targeting cell wall autolysins, has been stymied in part due to high levels of apparent enzymatic redundancy. In this study, we report a subset of E. coli amidases involved in cell separation during cell division are not redundant and instead are preferentially active during growth in distinct pH environments. Specifically, we discover E. coli amidases AmiB and AmiC are activated by acidic pH. Three semi-redundant periplasmic regulators—NlpD, EnvC, and YgeR—collectively mediate low pH-dependent stimulation of amidase activity. This discovery contributes to our understanding of how the cell wall remains robust across diverse environmental conditions and reveals opportunities for the development of condition-specific antimicrobial agents.

Ambient pH and Calcium Concentration as Modifiers of Growth and Calcium Dynamics of Brook Trout, Salvelinus fontinalis

1984 ◽  
Vol 41 (12) ◽  
pp. 1774-1780 ◽  
Author(s):  
David W. Rodgers
Keyword(s):  
Brook Trout ◽  
Calcium Concentration ◽  
Salvelinus Fontinalis ◽  
Axial Skeleton ◽  
Low Ph ◽  
Fish Growth ◽  
Calcium Dynamics ◽  
Experimental Fish ◽  
Low Calcium ◽  
High Calcium

Juvenile brook trout, Salvelinus fontinalis, were maintained in water of pH 5.3 or 6.5 and calcium concentrations of 5 or 40 mg/L to determine the effects of these factors on fish growth and calcium dynamics. Growth rates varied more than twofold and were significantly reduced by both low ambient calcium concentration and low pH. In contrast, calcium dynamics of the fish were significantly affected by calcium concentration but not pH. Brook trout in low-calcium water retained less labeled dietary calcium and deposited less labeled calcium in axial skeleton and visceral tissues than fish in high-calcium water. Calcium concentrations of the skin and fins were slightly but significantly reduced among fish in low-calcium water, but neither pH nor ambient calcium concentration significantly affected ash content or calcium concentration of axial skeleton and visceral tissues of experimental fish.

Luteinizing hormone stimulation of in vitro ovulation in brook trout (Salvelinus fontinalis) involves follicle contraction and activation of proteolytic genes

2013 ◽  
Vol 188 ◽  
pp. 175-182 ◽  
Author(s):  
Diego Crespo ◽  
Kousik Pramanick ◽  
Frederick W. Goetz ◽  
Josep V. Planas
Keyword(s):  
Luteinizing Hormone ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Hormone Stimulation ◽  
Stimulation Of

Elevated Levels of Arginine Vasotocin in the Brain of Brook Trout (Salvelinus fontinalis) from Acid Lakes: A Field Test of a Potential Biomarker for Acid Stress

1993 ◽  
Vol 50 (8) ◽  
pp. 1717-1727 ◽  
Author(s):  
A. Hontela ◽  
J. B. Rasmussen ◽  
K. Lederis ◽  
H. V. Tra ◽  
G. Chevalier
Keyword(s):  
Body Size ◽  
Field Test ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acid Stress ◽  
Low Ph ◽  
Arginine Vasotocin ◽  
Potential Biomarker ◽  
Different Seasons ◽  
The Relationship

The levels of arginine vasotocin (AVT), an osmoregulatory peptide, were determined by radioimmunoassay in brain tissue of brook trout (Salvelinus fontinalis) of a wide size range (50–380 mm) from softwater Laurentian lakes ranging in pH from 5.0 to 6.9 at different seasons. Multivariate models (ANCOVA) were developed to quantify the relationship between AVT, pH, body size, and season. Brain AVT levels increased with body size, and the allometric slope was highest in the low-pH lakes (pH 5.0-5.5). Although brook trout > 150 mm had higher brain AVT levels at low pH, no significant differences were detected for brook trout < 150 mm. We hypothesize that the sensitivity of brook trout at the parr stage to acid stress may be linked to their inability to mobilize a hormonal response involving AVT. The seasonal variation in brain AVT levels was similar in all the lakes studied, summer levels being the highest. Although this field study revealed that AVT levels depend also on factors other than acid stress (body size and season), our ANCOVA models allow adjustment for the effects of these covariables. Analyses of this type can be used to field test and calibrate biomarkers for use in ecotoxicology.

Plasma electrolytes, gill aluminum content, and gill morphology of juvenile Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) indigenous to acidic streams of Nova Scotia

1990 ◽  
Vol 68 (6) ◽  
pp. 1270-1280 ◽  
Author(s):  
G. L. Lacroix ◽  
D. J. Hood ◽  
C. S. Belfry ◽  
T. G. Rand
Keyword(s):  
Nova Scotia ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Low Ph ◽  
Secondary Lamellae ◽  
Exchangeable Al ◽  
Plasma Electrolytes ◽  
Gill Morphology

Plasma electrolytes and gill [Al] were determined and gill morphology and histology were examined in Atlantic salmon (Salmo salar) parr and brook trout (Salvelinus fontinalis) from feral populations in acidic streams of southwest Nova Scotia. Plasma [Na+] and [Cl−] were lowest in fish from streams with the lowest pH levels, but there were no correlations between plasma [Na+] or [Cl−] and exchangeable [Al] in streams for both species. Gill [Al] increased exponentially with increasing exchangeable [Al] in water, but was less than 100 μg/g dry weight in both species. There were no correlations between plasma [Na+] or [Cl−] and gill [Al] for both species, and plasma [Na+] and [Cl−] were ultimately linked to low pH. Scanning electron microscopy of gills showed normal primary and secondary lamellae, with few signs of fusion or hyperplasia, only a slight amount of mucus, regular chloride cell crypts, and epithelial cells with distinct microridges. Histology of gill sections showed few lesions in the primary lamellae but some focal histologic lesions in the secondary lamellae of greater than 50% of fish, regardless of ambient pH or [Al]. The histopathology included hypertrophy of individual epithelial, mucous, and chloride cells, clubbing of tips of secondary lamellae, and localized epithelial hyperplasia. These features were focal and not comparable to the extensive morphological changes or histologic lesions usually attributed to high [Al] at low pH. Dissolved organic carbon concentrations greater than 5 mg/L in the acidic streams apparently afforded protection against Al effects at concentrations of at least 360 μg total Al/L.

Aluminum and Acid Toxicity to Two Strains of Brook Trout (Salvelinus fontinalis)

1990 ◽  
Vol 47 (8) ◽  
pp. 1641-1648 ◽  
Author(s):  
C G. Ingersoll ◽  
D. D. Gulley ◽  
D. R. Mount ◽  
M. E. Mueller ◽  
J. D. Fernandez ◽  
...  
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Low Ph ◽  
Chloride Cells ◽  
Free Swimming ◽  
Field Exposure ◽  
Fish Weight ◽  
Gill Histology ◽  
Acid Toxicity

Two strains of 1 yr-old brook trout were exposed to 14 combinations of pH, aluminum, and calcium during a 28-d experiment. Survival, weight, and gill histology of both strains were affected similarly by pH, aluminum, and calcium exposure. Survival was reduced at inorganic monomeric aluminum concentrations (IA1) of 29 μg/L at pH 5.2 and [Formula: see text] at pH 4.4 and 4.8. Fish weight was reduced with exposure to pH below 4.8 or aluminum concentrations [Formula: see text]. The gills sampled from fish exposed to low pH exhibited lifting of the outer epithelium and hypertrophy (increase in size) of chloride and epithelial cells. The response of gills sampled from fish exposed to low pH and elevated aluminum was more pronounced relative to the low pH exposure alone. In addition to the effects observed in the low pH exposed fish, the gills from fish exposed to both acid and aluminum exhibited vacuolation and degeneration of epithelial and chloride cells and the presence of dense cells. Finally, fish confined in PVC tubes designed to mimic in situ field exposure procedures were more sensitive to the toxic effects of acid and aluminum compared to free-swimming fish. Caution must be taken when extrapolating safe field levels from in situ exposures of caged fish.

Effect of Long-Term Exposure to Acidf Aluminum, and Low Calcium on Adult Brook Trout (Salvelinus fontimlis). 2. Vitellogenesss and Osmoregulation

1988 ◽  
Vol 45 (9) ◽  
pp. 1633-1642 ◽  
Author(s):  
D. R. Mount ◽  
J. R. Hockett ◽  
W. A. Gern
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Plasma Osmolality ◽  
Low Ph ◽  
Reproductive Physiology ◽  
Treatment Conditions ◽  
Plasma Estradiol ◽  
Survival And Growth ◽  
All Treatment

Adult brook trout (Salvelinus fontinalis) were exposed for 193 d (previtellogenesis to spawning) to six combinations of acid, Al, and low Ca. Survival and growth were reduced by low pH combined with low Ca concentrations. After 41 d of exposure, fish in ail low pH exposures showed depressed plasma osmolality and Na concentrations, but by day 97 this apparent osmoregulatory stress was compensated for in all but the most severe treatment (pH 4.97, 47 μg inorganic Al/L, 0.5 mg Ca/L). At the observed peak of yolking (day 147), fish exposed to this treatment also had mean concentrations of plasma estradiol, vitellogenin, and Ca of only half control values. Fecundity (eggs per female) was significantly reduced as well, but this reduction was due in part to decreased growth. Despite these abnormalities in ionoregulatory and reproductive physiology, fish in all treatment conditions produced mature eggs. Among fish in stressful conditions, individual variation in growth and physiological parameters appeared to be correlated with osmoregulatory status. We hypothesize that the suite of physiological disturbances observed are linked to osmoregulatory impairment.

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