Acid and Aluminum Effects on Sodium Homeostasis and Survival of Acid-Sensitive and Acid-Tolerant Cladocera

1992 ◽  
Vol 49 (11) ◽  
pp. 2392-2398 ◽  
Author(s):  
Karl E. Havens
Keyword(s):  
Acid Stress ◽  
Relative Increase ◽  
Al Toxicity ◽  
Whole Body ◽  
Population Declines ◽  
Daphnia Galeata ◽  
Sodium Homeostasis ◽  
Bosmina Longirostris ◽  
Acid Tolerant ◽  
Daphnia Galeata Mendotae

Acid-sensitive (Daphnia galeata mendotae) and acid-tolerant (Bosmina longirostris) cladocerans were exposed to 0, 100, or 200 μg Al/L at pH 4.5, 6.0, or 7.5. Whole-body Na content and survivals were determined after 12- and 24-h exposures to the nine treatments. Daphnia galeata mendotae experienced significant decreases in body Na content and survival at pH 4.5. Aluminum effects were pH dependent. At pH 7.5 and 6.0, Na content and survival declined with increasing Al; at pH 4.5, the highest Al concentration enhanced Na content and prolonged survival. Bosmina longirostris Na content and survival were only slightly reduced at pH 4.5, and there were no significant Al or pH × Al interaction effects. The results support the view that (1) the extinction of D. galeata mendotae and the relative increase of B. longirostris during lake acidification are largely due to differential impacts of acid stress on osmoregulation and (2) Al toxicity might also be a factor responsible for D. galeata mendotae population declines, which are most pronounced near pH 6.0.

Population Dynamics of Daphnia galeata mendotae as Modified by Chronic Cadmium Stress

1978 ◽  
Vol 35 (4) ◽  
pp. 461-469 ◽  
Author(s):  
J. S. Marshall
Keyword(s):  
Population Dynamics ◽  
Carrying Capacity ◽  
Brood Size ◽  
Lake Michigan ◽  
Cadmium Stress ◽  
Whole Body ◽  
Average Weight ◽  
Daphnia Galeata ◽  
Female Ratio ◽  
Daphnia Galeata Mendotae

Forty populations of Daphnia galeata mendotae were maintained for 22 wk (or until they became extinct) in a medium consisting of filtered Lake Michigan water to which Chlamydomonas reinhardi and different concentrations of a mixture of labelled (109Cd) plus stable CdCl2 were added 24 h before use. The medium was changed daily Monday through Fridays. Weekly determinations were made of total numbers, average individual dry weight, mean brood size, egg–female ratio, aborted eggs and embryos, and average whole-body 109Cd content. Chronic cadmium stress reduced the populations' average numbers and biomass, while it increased the populations' turnover rates, temporal variability, probability of extinction, and proportion of ovigerous females. For individuals there was increased prenatal mortality, reduced life expectancy, increased average weight, and increased brood size. Due to compensatory increases in the proportion of ovigerous females and mean brood size, the cadmium sensitivity of population attributes was considerably less than that of the most sensitive individual attribute, prenatal mortality. A linear relationship between population carrying capacity (relative mean numbers) and added cadmium concentration indicated that the effective concentration for a 50% reduction of carrying capacity (EC50) is 7.7 μg Cd/L and that for a 1% reduction (EC1) is 0.15 μg Cd/L. An increase of 0.15 μg Cd/L in Lake Michigan itself, barring synergistic interaction with other factors in the lake, would probably not have a detectable effect on the population dynamics of D. galeata mendotae. Key words: zooplankton dynamics, stress ecology, Daphnia galeata mendotae, cadmium, heavy metals, toxic substances, Laurentian Great Lakes

Influence of food density on respiration rate of two crustacean plankters, Daphnia galeata and Bosmina longirostris

Oecologia ◽  
1990 ◽  
Vol 82 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Jotaro Urabe ◽  
Yasunori Watanabe
Keyword(s):  
Respiration Rate ◽  
Food Density ◽  
Daphnia Galeata ◽  
Bosmina Longirostris ◽  
Influence Of Food

Dieldrin reduces male production and sex ratio in Daphnia galeata mendotae

1999 ◽  
Vol 15 (1-2) ◽  
pp. 193-200 ◽  
Author(s):  
Christine M. Merritt ◽  
Laura Torrentera ◽  
Katherine M. Winter ◽  
Christopher K. Tornehl ◽  
Kristin Girvin ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Male Production ◽  
Daphnia Galeata ◽  
Daphnia Galeata Mendotae

Effects of environmental pH on the ionic composition of the white sucker (Catostomus commersoni) and pumpkinseed (Lepomis gibbosus)

1984 ◽  
Vol 62 (2) ◽  
pp. 249-259 ◽  
Author(s):  
Grant A. Fraser ◽  
Harold H. Harvey
Keyword(s):  
Ionic Composition ◽  
Hard Water ◽  
Soft Water ◽  
Whole Body ◽  
Lepomis Gibbosus ◽  
White Sucker ◽  
Catostomus Commersoni ◽  
Handling Stress ◽  
Plasma Ions ◽  
Acid Tolerant

White sucker (Catostomus commersoni) exposed to soft water ([Ca2+] = 0.207 mequiv./L) below pH 5 showed [Na+] and [Cl−] losses, that were approximately the same in plasma and whole body. At pH 4.5 (6- to 19-day exposure), body and plasma [Na+] were approximately 17% lower than in white sucker held at pH 6.6, and 42% lower in fish at pH 4 (<2 days). Since plasma ions are known to be affected by handling stress, whole-body [Na+] and [Cl−] in fishes may be a more useful indicator of ionoregulation status under field conditions. Pumpkinseed (Lepomis gibbosus) were clearly more acid tolerant, as indicated by greater survival and reduced ion loss in the same acid environments as white sucker. After 19 days exposure at pH 4.5, body Na+ was reduced by 8%; at pH 4 body Na+ was reduced by 38%. Hence, at pH 4, the net Na+ loss experienced by this acid-tolerant fish was similar to that observed in white sucker; however, the rate of loss in white sucker was 11-fold greater. White sucker in acidified, decarbonated hard water ([Ca2+] = 2.110 mequiv./L) at pH 4 (6 or 19 days), showed a 35% lower whole-body [Na+] than in fish held at pH levels of 4.5, 5, and 6.3; [Cl−] was 39% less. However, at pH 4 the ratio of whole-body Na+:Cl− losses was 1.4:1 in hard water and 1.08:1 in soft water. Total Na+ loss at pH 4 was similar to that in white sucker held at the same pH in soft water; however, the rate of loss in soft water was 15-fold greater.

Freshwater Zooplankton Community Structure: Introduction of Large Invertebrate Predators and Large Herbivores to a Small Species Community

1988 ◽  
Vol 45 (10) ◽  
pp. 1758-1770 ◽  
Author(s):  
Michael J. Vanni
Keyword(s):  
Introduced Species ◽  
Zooplankton Community ◽  
Zooplankton Species ◽  
Small Species ◽  
Daphnia Galeata ◽  
Resident Species ◽  
Large Herbivores ◽  
Fishless Lakes ◽  
Invertebrate Predators ◽  
Daphnia Galeata Mendotae

Two hypotheses have been proposed to explain the scarcity of small zooplankton species in fishless lakes, in which large zooplankton species dominate: (1) selective predation on small species by large invertebrate predators and (2) competitive suppression of small species by large herbivores. These hypotheses were tested at the Experimental Lakes Area (ELA) by introducing a large invertebrate predator, Chaoborus americanus, and a large herbivore, Daphnia catawba, both common in fishless ELA lakes, into a zooplankton community typical of ELA lakes with fish (small zooplankton species present). Chaoborus had much more of an impact than D. catawba on resident zooplankton, although both introduced species significantly reduced the abundance of some resident species. Daphnia galeata mendotae, the dominant species in the absence of introduced species, was reduced to virtual extinction by Chaoborus. The cladocerans Bosmina and Diaphanosoma, the copepods Diaptomus spp., and the rotifer Conochilus also were reduced in abundance by Chaoborus. Daphnia galeata mendotae and Bosmina were the only resident species consistently reduced in abundance by D. catawba. These results support current conceptual models that depict invertebrate predation as an important factor responsible for the relative scarcity of small zooplankton species in fishless lakes.

New microsatellite primers for Daphnia galeata mendotae

2004 ◽  
Vol 4 (4) ◽  
pp. 544-546 ◽  
Author(s):  
JENNIFER A. FOX
Keyword(s):  
Microsatellite Primers ◽  
Daphnia Galeata ◽  
Daphnia Galeata Mendotae

Periodicity of Egg Laying and Egg Age Distributions in Planktonic Cladocera

1984 ◽  
Vol 41 (3) ◽  
pp. 409-413 ◽  
Author(s):  
Alan J. Tessier
Keyword(s):  
Negative Correlation ◽  
Natural Populations ◽  
Egg Laying ◽  
Daphnia Galeata ◽  
Molt Cycle ◽  
Egg Development ◽  
Daphnia Species ◽  
Diel Cycles ◽  
Development Times ◽  
Daphnia Galeata Mendotae

In natural populations of planktonic Cladocera, I observed significant diel, molt cycle, and cohort periodicity of egg laying. Diel cycles of egg laying were pronounced in one population of Daphnia galeata mendotae; most females laid eggs only at dawn. There was a strongly negative correlation between diel egg laying cycles of coexisting Daphnia species. Egg laying in two Daphnia populations cycled with a period approximating the egg development times, suggesting a synchronization of individual molt cycles. Noncontiguous reproduction was characteristic of a population of Holopedium gibberum. Adults reproduced synchronously and then died; there was little overlap of generations.

Anti-Escherichia coliO157:H7 activity of free fatty acids under varying pH

2010 ◽  
Vol 56 (3) ◽  
pp. 263-267 ◽  
Author(s):  
Jinli Yang ◽  
Xianzhi Hou ◽  
Priya S. Mir ◽  
Tim A. McAllister
Keyword(s):  
Fatty Acids ◽  
Bactericidal Activity ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Capric Acid ◽  
Luria Bertani ◽  
E Coli ◽  
Luria Bertani Broth ◽  
Colony Forming Units ◽  
Acid Tolerant

Following screening of 4 strains of Escherichia coli O157:H7 (E32511, E318N, H4420N, and R508N) for acid tolerance, strain H4420N was selected for further study into the influence of pH on bactericidal activity of 6 fatty acids (capric, lauric, palmitic, oleic, linoleic, and linolenic). Strain H4420N was cultured for 6 h in Luria–Bertani broth amended with individual fatty acids at 20 mmol/L, with pH adjusted to 7.0, 4.3, or 2.5. None of the fatty acids exhibited bactericidal activity at pH 7.0 (p >0.05). At pH 4.3, only capric, lauric, and linoleic acids reduced viability of H4420N (p < 0.05). At pH 2.5, oleic (C18:1) and linolenic (C18:3) acids had modest effects on H4420N viability, whereas capric (C10:0), lauric (C12:0), and linoleic (C18:2) acids resulted in a reduction ≥5 log10colony-forming units (CFU)/mL (p < 0.05). Capric and lauric acids were examined further at pH 2.5 over a range of concentrations (0.15–20 mmol/L). After 10 min of exposure, 5 log10 CFU/mL reductions (p < 0.05) were achieved by lauric acid at 2.5 mmol/L and by capric acid at 0.31 mmol/L. Acid stress increased the sensitivity of acid-tolerant E. coli O157:H7 strain H4420N to fatty acids. Including sources of these fatty acids in diets for cattle might impair the ability of this zoonotic pathogen to survive passage through the stomach, possibly reducing the potential for its colonization in the lower gut.

Whole body fat oxidation is related to in situ adipose tissue lipolytic response to isoproterenol in males

1998 ◽  
Vol 275 (3) ◽  
pp. E400-E404
Author(s):  
S. Snitker ◽  
J. Hellmér ◽  
M. Boschmann ◽  
M. B. Monroe ◽  
E. Ravussin
Keyword(s):  
Adipose Tissue ◽  
Weight Gain ◽  
Body Fat ◽  
Fat Oxidation ◽  
Relative Increase ◽  
Whole Body ◽  
Glycerol Concentration ◽  
Pima Indians ◽  
Adrenergic Stimulation ◽  
Microdialysis Probe

A high 24-h respiratory quotient (RQ), i.e., low fat oxidation, predicts weight gain. To determine whether impaired fat mobilization (lipolysis) may contribute to weight gain, we studied the relation between lipolytic response to nonselective β-adrenergic stimulation and RQ measured in a respiratory chamber in 21 males (11 Caucasians, 10 Pima Indians; age 32 ± 5 yr, weight 93 ± 24 kg, body fat 30 ± 8%; means ± SD) and 23 females (10 Caucasians, 13 Pima Indians; age 32 ± 9 yr, weight 95 ± 26 kg, body fat 44 ± 8%). Lipolytic response was assessed as the relative increase in dialysate glycerol concentration (% above baseline) when isoproterenol (1 μmol/l) was added to the perfusate of a microdialysis probe inserted in the abdominal subcutaneous adipose tissue. In males, but not in females, basal RQ measured during sleep from 0500 to 0630 and adjusted for waist circumference was negatively correlated to lipolytic response ( r = −0.66, P = 0.001). The results suggest that in males, impaired β-adrenergic-mediated lipolysis may contribute to low rates of fat oxidation, a condition known to predispose to weight gain.

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