Variation in Major Ion Concentration of Cambarus robustus and Orconectes rusticus Following Exposure to Low pH

1986 ◽  
Vol 43 (10) ◽  
pp. 2040-2044 ◽  
Author(s):  
Lois Hollett ◽  
Michael Berrill ◽  
Locke Rowe
Keyword(s):  
Chronic Exposure ◽  
Low Ph ◽  
Ion Concentration ◽  
Acute Exposure ◽  
Stage Iii ◽  
Orconectes Rusticus ◽  
Ion Regulation ◽  
Major Ion ◽  
Acid Tolerant ◽  
Total Body

Cambarus robustus is more tolerant of low environmental pH than Orconectes rusticus and this tolerance reflects a difference in ion regulation physiology. Chronic exposure (96 h) of the acid-tolerant C. robustus to pH 3.8 soft water did not significantly change haemolymph [Na+] or [Ca2+] of the adults or total body [Na+] of the juveniles relative to the control (pH 6.5). In contrast, the intolerant O. rusticus showed a significant decrease in [Na+] and increase in [Ca2+] in adult haemolymph (Wood and Rogano. 1986. Can. J. Fish. Aquat. Sci. 43: 1017–1026) and an increase in total body [Na+] of stage III juveniles following acute exposure to pH 3.8 compared with the pH 6.5 control.

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.

Branchial and Renal Acid and Ion Fluxes in the Rainbow Trout, Salmo Gairdneri, at Low Environmental pH

1981 ◽  
Vol 93 (1) ◽  
pp. 101-118 ◽  
Author(s):  
D. G. McDONALD ◽  
C.M. WOOD
Keyword(s):  
Rainbow Trout ◽  
Significant Contribution ◽  
Low Ph ◽  
The Body ◽  
Salmo Gairdneri ◽  
Ion Regulation ◽  
Progressive Decline ◽  
Blood Ph ◽  
Acid Load ◽  
Total Body

Rainbow trout were exposed for 4 days to an environmental pH averaging 4.2, an exposure which resulted in a continuous net branchial influx of acid. The influx provoked a progressive depression in blood pH and [HCO3−], virtually complete by 48 h, and a marked increase in renal acid excretion, also complete by 48 h. The increase in the latter was sufficient to remove, at maximum, about half of the protons entering at the gills; those remaining were buffered in body fluids. The low pH exposure also impaired gill ion regulation as indicated by continuous net branchial losses of Na+, Cl− and K+ and by a progressive decline in plasma Na+ and Cl− levels. Evidence is presented which indicates that there was a significant contribution by the intracellular compartment both to the total body ion losses and to the buffering of the body acid load.

Association of Dyskalemias with Ischemic Stroke in Advanced Chronic Kidney Disease Patients Transitioning to Dialysis

2021 ◽  
pp. 1-9
Author(s):  
Ankur A. Dashputre ◽  
Keiichi Sumida ◽  
Fridtjof Thomas ◽  
Justin Gatwood ◽  
Oguz Akbilgic ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Ischemic Stroke ◽  
Kidney Disease ◽  
Lower Risk ◽  
Chronic Exposure ◽  
Cox Regression ◽  
Acute Exposure ◽  
Continuous Exposure ◽  
Advanced Chronic Kidney Disease

<b><i>Introduction:</i></b> Hypo- and hyperkalemia are associated with a higher risk of ischemic stroke. However, this association has not been examined in an advanced chronic kidney disease (CKD) population. <b><i>Methods:</i></b> From among 102,477 US veterans transitioning to dialysis between 2007 and 2015, 21,357 patients with 2 pre-dialysis outpatient estimated glomerular filtration rates &#x3c;30 mL/min/1.73 m<sup>2</sup> 90–365 days apart and at least 1 potassium (K) each in the baseline and follow-up period were identified. We separately examined the association of both baseline time-averaged K (chronic exposure) and time-updated K (acute exposure) treated as categorized (hypokalemia [K &#x3c;3.5 mEq/L] and hyperkalemia [K &#x3e;5.5 mEq/L] vs. referent [3.5–5.5 mEq/L]) and continuous exposure with time to the first ischemic stroke event prior to dialysis initiation using multivariable-adjusted Cox regression models. <b><i>Results:</i></b> A total of 2,638 (12.4%) ischemic stroke events (crude event rate 41.9 per 1,000 patient years; 95% confidence interval [CI] 40.4–43.6) over a median (Q<sub>1</sub>–Q<sub>3</sub>) follow-up time of 2.56 (1.59–3.89) years were observed. The baseline time-averaged K category of hypokalemia (adjusted hazard ratio [aHR], 95% CI: 1.35, 1.01–1.81) was marginally associated with a significantly higher risk of ischemic stroke. However, time-updated hyperkalemia was associated with a significantly lower risk of ischemic stroke (aHR, 95% CI: 0.82, 0.68–0.98). The exposure-outcome relationship remained consistent when using continuous K levels for both the exposures. <b><i>Discussion/Conclusion:</i></b> In patients with advanced CKD, hypokalemia (chronic exposure) was associated with a higher risk of ischemic stroke, whereas hyperkalemia (acute exposure) was associated with a lower risk of ischemic stroke. Further studies in this population are needed to explore the mechanisms underlying these associations.

scholarly journals Acid tolerance in early colonizers of oral biofilms

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Gabriella Boisen ◽  
Julia R. Davies ◽  
Jessica Neilands
Keyword(s):  
Acid Tolerance ◽  
Low Ph ◽  
Salivary Proteins ◽  
Confocal Scanning Laser Microscopy ◽  
Planktonic Cells ◽  
Tolerance Development ◽  
Salivary Pellicle ◽  
Oral Biofilms ◽  
Acid Tolerant

Abstract Background In caries, low pH drives selection and enrichment of acidogenic and aciduric bacteria in oral biofilms, and development of acid tolerance in early colonizers is thought to play a key role in this shift. Since previous studies have focussed on planktonic cells, the effect of biofilm growth as well as the role of a salivary pellicle on this process is largely unknown. We explored acid tolerance and acid tolerance response (ATR) induction in biofilm cells of both clinical and laboratory strains of three oral streptococcal species (Streptococcus gordonii, Streptococcus oralis and Streptococcus mutans) as well as two oral species of Actinomyces (A. naeslundii and A. odontolyticus) and examined the role of salivary proteins in acid tolerance development. Methods Biofilms were formed on surfaces in Ibidi® mini flow cells with or without a coating of salivary proteins and acid tolerance assessed by exposing them to a challenge known to kill non-acid tolerant cells (pH 3.5 for 30 min) followed by staining with LIVE/DEAD BacLight and confocal scanning laser microscopy. The ability to induce an ATR was assessed by exposing the biofilms to an adaptation pH (pH 5.5) for 2 hours prior to the low pH challenge. Results Biofilm formation significantly increased acid tolerance in all the clinical streptococcal strains (P < 0.05) whereas the laboratory strains varied in their response. In biofilms, S. oralis was much more acid tolerant than S. gordonii or S. mutans. A. naeslundii showed a significant increase in acid tolerance in biofilms compared to planktonic cells (P < 0.001) which was not seen for A. odontolyticus. All strains except S. oralis induced an ATR after pre-exposure to pH 5.5 (P < 0.05). The presence of a salivary pellicle enhanced both acid tolerance development and ATR induction in S. gordonii biofilms (P < 0.05) but did not affect the other bacteria to the same extent. Conclusions These findings suggest that factors such as surface contact, the presence of a salivary pellicle and sensing of environmental pH can contribute to the development of high levels of acid tolerance amongst early colonizers in oral biofilms which may be important in the initiation of caries.

scholarly journals Vasoactive Effects of Acute Ergot Exposure in Sheep

Toxins ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 291
Author(s):  
Rossalin Yonpiam ◽  
Jair Gobbet ◽  
Ashok Jadhav ◽  
Kaushik Desai ◽  
Barry Blakley ◽  
...  
Keyword(s):  
Single Dose ◽  
Chronic Exposure ◽  
Contractile Response ◽  
Ergot Alkaloids ◽  
Acute Exposure ◽  
Control Group ◽  
Vascular Effects ◽  
Adrenergic Antagonist ◽  
Vascular Sensitivity ◽  
Dose Dependent

Ergotism is a common and increasing problem in Saskatchewan’s livestock. Chronic exposure to low concentrations of ergot alkaloids is known to cause severe arterial vasoconstriction and gangrene through the activation of adrenergic and serotonergic receptors on vascular smooth muscles. The acute vascular effects of a single oral dose with high-level exposure to ergot alkaloids remain unknown and are examined in this study. This study had two main objectives; the first was to evaluate the role of α1-adrenergic receptors in mediating the acute vasocontractile response after single-dose exposure in sheep. The second was to examine whether terazosin (TE) could abolish the vascular contractile effects of ergot alkaloids. Twelve adult female sheep were randomly placed into control and exposure groups (n = 6/group). Ergot sclerotia were collected and finely ground. The concentrations of six ergot alkaloids (ergocornine, ergocristine, ergocryptine, ergometrine, ergosine, and ergotamine) were determined using HPLC/MS at Prairie Diagnostic Services Inc., (Saskatoon, SK, Canada). Each ewe within the treatment group received a single oral treatment of ground ergot sclerotia at a dose of 600 µg/kg BW (total ergot) while each ewe in the control group received water. Animals were euthanized 12 h after the treatment, and the pedal artery (dorsal metatarsal III artery) from the left hind limb from each animal was carefully dissected and mounted in an isolated tissue bath. The vascular contractile response to phenylephrine (PE) (α1-adrenergic agonist) was compared between the two groups before and after TE (α1-adrenergic antagonist) treatment. Acute exposure to ergot alkaloids resulted in a 38% increase in vascular sensitivity to PE compared to control (Ctl EC50 = 1.74 × 10−6 M; Exp EC50 = 1.079 × 10−6 M, p = 0.046). TE treatment resulted in a significant dose-dependent increase in EC50 in both exposure and control groups (p < 0.05 for all treatments). Surprisingly, TE effect was significantly more pronounced in the ergot exposed group compared to the control group at two of the three concentrations of TE (TE 30 nM, p = 0.36; TE 100 nM, p < 0.001; TE 300 nM, p < 0.001). Similar to chronic exposure, acute exposure to ergot alkaloids results in increased vascular sensitivity to PE. TE is a more potent dose-dependent antagonist for the PE contractile response in sheep exposed to ergot compared to the control group. This study may indicate that the dry gangrene seen in sheep, and likely other species, might be related to the activation of α1-adrenergic receptor. This effect may be reversed using TE, especially at early stages of the disease before cell death occurs. This study may also indicate that acute-single dose exposure scenario may be useful in the study of vascular effects of ergot alkaloids.

scholarly journals Genotoxic and Histopathological Effects of Chlorpyrifos on African Catfish, C. gariepinus and Ameliorative Potentials of Ackee Apple, blighia sapida Seed

2018 ◽  
Vol 6 (1) ◽  
pp. 1 ◽  
Author(s):  
Oluyinka Iyiolai ◽  
A. A. Adeagbo ◽  
W. S. Weliange ◽  
S. I. Abdulkareem ◽  
Anifowoshe T. Abass ◽  
...  
Keyword(s):  
Chronic Exposure ◽  
Clarias Gariepinus ◽  
Aquatic Organisms ◽  
Acute Exposure ◽  
Histopathological Analysis ◽  
African Catfish ◽  
Dependent Manner ◽  
Dose Dependent ◽  
Histopathological Effects ◽  
Positive Controls

Chlorpyrifos (CPF) is a very toxic pesticide commonly used for controlling agriculturally important pests. The present study investigates DNA damaging effects of CPF on Clarias gariepinus was assessed using genetic assays. Fish were exposed to varying concentrations of CPF (100ppm, 200ppm and 300ppm) at 96 hours (acute exposure). LC50 of the pesticide was found to be 120ppm and one-tenth of the LC50 (12ppm) was taken for the chronic exposure. Distilled water and colchicine were used as negative and positive controls respectively. After 28 days of chronic exposure, fish were fed with inclusion of B. sapida seed (powder) for 14 days. Liver and gills of the fish were removed following 96h exposure, days 7, 14 and 28 of the chronic exposure as well as after the period of amelioration (14 days) for CA assay and histopathological analysis. The results of CA assay showed statistically significant (p ˂ 0.05) increase in CA in a dose-dependent manner for all the exposed groups after acute exposure and time dependent after chronic exposure. Also, this study showed that CPF can potentially induce genotoxic and histopathological changes in fish and other aquatic organisms.

scholarly journals Adsorption of Cr6+ Onto Unmodified and Hydrochloric Acid Modified African Nutmeg Pod (Monodora myristica) from Aqueous Solution

2019 ◽  
pp. 1-8
Author(s):  
F. U. Okwunodulu ◽  
H. O. Chukwuemeka-Okorie ◽  
N. M. Mgbemena ◽  
J. B. I. Kalu
Keyword(s):  
Aqueous Solution ◽  
Metal Ion ◽  
Correlation Coefficients ◽  
Freundlich Isotherm ◽  
Low Ph ◽  
Ion Concentration ◽  
Isotherm Models ◽  
Particle Sizes ◽  
Monodora Myristica ◽  
Best Fit

The removal of Cr6+ from aqueous solution using unmodified and hydrochloric modified African nutmeg pod was studied. The effects of particle size, pH and initial metal ions concentration adsorbed were investigated. The amount of metal ion adsorbed increased as the initial metal ion concentration increased and also decreased at low pH of 2 for both modified and unmodified African nutmeg pod.  400 µm and 250 µm were the optimum particle sizes for both modified and unmodified African nutmeg pod respectively, values given as 75.8 mg/g for the modified and 93.39 mg/g for the unmodified. Generally, it was observed that the unmodified African nutmeg pod showed greater adsorption capacity than the modified African nutmeg pod. The equilibrium experimental data were examined via Langmuir and Freundlich isotherm models.  Freundlich isotherm model gave the best fit for the data in both unmodified and modified African nutmeg pod based on the correlation coefficients (R2 values) gotten. The results of the study showed that the African nutmeg pod is efficient for the removal of Cr6+ from aqueous solutions especially when unmodified.

Physiological Correlates of Interspecific Variation in Acid Tolerance in Fish

1988 ◽  
Vol 136 (1) ◽  
pp. 243-258 ◽  
Author(s):  
J. FREDA ◽  
D. G. MCDONALD
Keyword(s):  
Yellow Perch ◽  
Acid Tolerance ◽  
Binding Activity ◽  
Low Ph ◽  
Whole Body ◽  
Salmo Gairdneri ◽  
Survival Times ◽  
Ion Regulation ◽  
Sodium Efflux ◽  
Na Efflux

This study investigated ion regulation in relation to water pH in three species of fish of differing tolerance to low pH (common shiners, Notropis cornutus, most sensitive; rainbow trout, Salmo gairdneri, intermediate; yellow perch, Perca flavescens, least sensitive). Increasing sensitivity to exposure to low pH was characterized by shorter survival times, greater losses of whole-body ions, more complete inhibition of Na+ uptake, and greater stimulation of Na+ efflux, the latter being the most important factor in determining survival. Interspecific variations in acid tolerance were also correlated with Na+ transport characteristics at circumneutral pH; Km was directly correlated and Vmax inversely correlated with acid tolerance. In addition, there were large qualitative differences among the species in the Ca2+-dependence of Na+ efflux. Sodium efflux induced by low pH was markedly Ca2+-dependent in both trout and shiners in a manner consistent with a simple competition between Ca2+ and H+ for gill binding sites. The increased sensitivity of shiners relative to trout was related to lowered Ca2+- binding activity. In contrast, Na+ efflux in perch was virtually unaffected by water [Ca2+]. Similarly, La3+ (a Ca2+ antagonist) stimulated higher Na+ losses from shiners than from trout, but had little effect upon perch. Ionic losses produced by saturating La3+ concentrations were generally lower than those produced by H+, suggesting that Ca2+ displacement is not the only mechanism for increased gill permeability at low pH. Nonetheless, the results obtained are consistent with the notion that acid tolerance may be related to Ca2+-binding activity in some species (e.g. trout and shiners) although not in others (e.g. perch).

Application of Methanobrevibacter acididurans in anaerobic digestion

2004 ◽  
Vol 50 (6) ◽  
pp. 109-114 ◽  
Author(s):  
D.V. Savant ◽  
D.R. Ranade
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Methane Production ◽  
Volatile Fatty Acids ◽  
Low Ph ◽  
Anaerobic Digesters ◽  
Hydrogenotrophic Methanogen ◽  
Distillery Wastewater ◽  
Acid Tolerant ◽  
Acidic Conditions

To operate anaerobic digesters successfully under acidic conditions, hydrogen utilizing methanogens which can grow efficiently at low pH and tolerate high volatile fatty acids (VFA) are desirable. An acid tolerant hydrogenotrophic methanogen viz. Methanobrevibacter acididurans isolated from slurry of an anaerobic digester running on alcohol distillery wastewater has been described earlier by this lab. This organism could grow optimally at pH 6.0. In the experiments reported herein, M. acididurans showed better methanogenesis under acidic conditions with high VFA, particularly acetate, than Methanobacterium bryantii, a common hydrogenotrophic inhabitant of anaerobic digesters. Addition of M. acididurans culture to digesting slurry of acidogenic as well as methanogenic digesters running on distillery wastewater showed increase in methane production and decrease in accumulation of volatile fatty acids. The results proved the feasibility of application of M. acididurans in anaerobic digesters.

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