The effect of acid stress on survivorship and reproduction of Daphnia pulex (Crustacea: Cladocera)

1982 ◽  
Vol 60 (4) ◽  
pp. 573-579 ◽  
Author(s):  
W. E. Walton ◽  
S. M. Compton ◽  
J. D. Allan ◽  
R. E. Daniels
Keyword(s):  
Population Growth Rate ◽  
Daphnia Pulex ◽  
Acid Stress ◽  
Pond Water ◽  
Low Ph ◽  
Laboratory Simulation ◽  
Zooplankton Species ◽  
Field Surveys ◽  
Delayed Onset ◽  
Acute Test

Laboratory simulation of acid stress to a common cladoceran, Daphnia pulex, was conducted in pond water of varying acidity due to addition of H2SO4. An acute test using exposure times of 1 to 96 h and pH levels of 3.7 and 6.5 revealed virtually no effect at 4.3 and higher, while 4.2 and lower severely reduced survivorship. Very short (3-h) exposures caused nearly complete mortality at pH 3.7, while > 12 h exposure caused high mortality at pH of 4.0–4.2. A chronic 21-d life table test indicated a gradually increasing impairment of population growth rate potential (r) at pH 5.0 and below. This was due primarily to reduced survivorship and delayed onset of reproductive maturity. Those individuals which survived at lower pH levels produced broods equivalent to unstressed daphnids. While the tolerance of D. pulex to low pH does not appear to have been reported from field surveys, our results are in close agreement with the observed effects of increasing acidity on the distribution of other zooplankton species.

Inter- and Intra-specific Variability in the Response of Zooplankton to Acid Stress

1985 ◽  
Vol 42 (11) ◽  
pp. 1749-1754 ◽  
Author(s):  
Edmund E. Price ◽  
Michael C. Swift
Keyword(s):  
Natural Populations ◽  
Daphnia Pulex ◽  
Acid Stress ◽  
Intraspecific Variability ◽  
Early Summer ◽  
Low Ph ◽  
Acid Sensitivity ◽  
Chaoborus Americanus ◽  
Acute Bioassays ◽  
Mesocyclops Edax

We measured the toxicity of sulfuric acid to natural populations of Daphnia pulex, D. galeata mendotae, Simocephalus serrulatus, Mesocyclops edax, Chaoborus americanus, and C. punctipennis. Organisms were collected in the spring and fall from acidic (pH 5.4) and circumneutral (pH 6.3–7.5) ponds, and their response to low pH was compared in 48- or 96-h acute bioassays. Based on 48- and 96-h LC50, cladocerans were most susceptible to acid stress, followed by Mesocyclops and Chaoborus larvae. Simocephalus was the most tolerant cladoceran, followed by D. pulex then D. galeata mendotae. Daphnia populations tested in the spring or early summer were more tolerant of low pH than those tested in the fall. Mesocyclops edax from an acid pond were more tolerant than those from a neutral pond. The response of the two Chaoborus species to low pH were quite similar; their 96-h LC50 (2.00, 2.09) was two pH units lower than those of cladocerans and one pH unit lower than that of M. edax. Our data demonstrate interspecific variability in acid sensitivity and suggest intraspecific variability due to habitat and season.

scholarly journals Physiological responses of Daphnia pulex to acid stress

2009 ◽  
Vol 9 (1) ◽  
pp. 9 ◽  
Author(s):  
Anna K Weber ◽  
Ralph Pirow
Keyword(s):  
Physiological Responses ◽  
Daphnia Pulex ◽  
Acid Stress

scholarly journals Population Heterogeneity of Lactobacillus plantarum WCFS1 Microcolonies in Response to and Recovery from Acid Stress

2008 ◽  
Vol 74 (24) ◽  
pp. 7750-7758 ◽  
Author(s):  
Colin J. Ingham ◽  
Marke Beerthuyzen ◽  
Johan van Hylckama Vlieg
Keyword(s):  
Lactobacillus Plantarum ◽  
Porous Ceramic ◽  
Acid Stress ◽  
Low Ph ◽  
Phenotypic Heterogeneity ◽  
Population Heterogeneity ◽  
Positive Bacterium ◽  
Ceramic Support ◽  
Dividing Cells ◽  
Stressed Cells

ABSTRACT Within an isogenic microbial population in a homogenous environment, individual bacteria can still exhibit differences in phenotype. Phenotypic heterogeneity can facilitate the survival of subpopulations under stress. As the gram-positive bacterium Lactobacillus plantarum grows, it acidifies the growth medium to a low pH. We have examined the growth of L. plantarum microcolonies after rapid pH downshift (pH 2 to 4), which prevents growth in liquid culture. This acidification was achieved by transferring cells from liquid broth onto a porous ceramic support, placed on a base of low-pH MRS medium solidified using Gelrite. We found a subpopulation of cells that displayed phenotypic heterogeneity and continued to grow at pH 3, which resulted in microcolonies dominated by viable but elongated (filamentous) cells lacking septation, as determined by scanning electron microscopy and staining cell membranes with the lipophilic dye FM4-64. Recovery of pH-stressed cells from these colonies was studied by inoculation onto MRS-Gelrite-covered slides at pH 6.5, and outgrowth was monitored by microscopy. The heterogeneity of the population, calculated from the microcolony areas, decreased with recovery from pH 3 over a period of a few hours. Filamentous cells did not have an advantage in outgrowth during recovery. Specific regions within single filamentous cells were more able to form rapidly dividing cells, i.e., there was heterogeneity even within single recovering cells.

Tetramerization at Low pH Licenses DNA Methylation Activity of M.HpyAXI in the Presence of Acid Stress

2020 ◽  
Vol 432 (2) ◽  
pp. 324-342 ◽  
Author(s):  
Naveen Narayanan ◽  
Arun Banerjee ◽  
Deepti Jain ◽  
Dhananjaya S. Kulkarni ◽  
Rahul Sharma ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Acid Stress ◽  
Low Ph ◽  
Methylation Activity

scholarly journals Identification and Inactivation of Genetic Loci Involved with Lactobacillus acidophilus Acid Tolerance

2004 ◽  
Vol 70 (9) ◽  
pp. 5315-5322 ◽  
Author(s):  
M. Andrea Azcarate-Peril ◽  
Eric Altermann ◽  
Rebecca L. Hoover-Fitzula ◽  
Raul J. Cano ◽  
Todd R. Klaenhammer
Keyword(s):  
Amino Acid ◽  
Lactobacillus Acidophilus ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Low Ph ◽  
Open Reading Frames ◽  
Amino Acid Permease ◽  
Physiological Limits ◽  
Insertional Inactivation ◽  
Genes Encoding

ABSTRACT Amino acid decarboxylation-antiporter reactions are one of the most important systems for maintaining intracellular pH between physiological limits under acid stress. We analyzed the Lactobacillus acidophilus NCFM complete genome sequence and selected four open reading frames with similarities to genes involved with decarboxylation reactions involved in acid tolerance in several microorganisms. Putative genes encoding an ornithine decarboxylase, an amino acid permease, a glutamate γ-aminobutyrate antiporter, and a transcriptional regulator were disrupted by insertional inactivation. The ability of L. acidophilus to survive low-pH conditions, such as those encountered in the stomach or fermented dairy foods, was investigated and compared to the abilities of early- and late-stationary-phase cells of the mutants by challenging them with a variety of acidic conditions. All of the integrants were more sensitive to low pH than the parental strain. Interestingly, each integrant also exhibited an adaptive acid response during logarithmic growth, indicating that multiple mechanisms are present and orchestrated in L. acidophilus in response to acid challenge.

scholarly journals Supramolecular assembly of the Escherichia coli LdcI upon acid stress

2020 ◽  
Vol 118 (2) ◽  
pp. e2014383118
Author(s):  
Matthew Jessop ◽  
Clarissa Liesche ◽  
Jan Felix ◽  
Ambroise Desfosses ◽  
Megghane Baulard ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stress Response ◽  
Fluorescent Protein ◽  
Mutational Analysis ◽  
Acid Stress ◽  
Low Ph ◽  
Supramolecular Organization ◽  
Cell Periphery ◽  
Wide Field ◽  
Acid Stress Response

Pathogenic and commensal bacteria often have to resist the harsh acidity of the host stomach. The inducible lysine decarboxylase LdcI buffers the cytosol and the local extracellular environment to ensure enterobacterial survival at low pH. Here, we investigate the acid stress-response regulation of Escherichia coli LdcI by combining biochemical and biophysical characterization with negative stain and cryoelectron microscopy (cryo-EM) and wide-field and superresolution fluorescence imaging. Due to deleterious effects of fluorescent protein fusions on native LdcI decamers, we opt for three-dimensional localization of nanobody-labeled endogenous wild-type LdcI in acid-stressed E. coli cells and show that it organizes into distinct patches at the cell periphery. Consistent with recent hypotheses that in vivo clustering of metabolic enzymes often reflects their polymerization as a means of stimulus-induced regulation, we show that LdcI assembles into filaments in vitro at physiologically relevant low pH. We solve the structures of these filaments and of the LdcI decamer formed at neutral pH by cryo-EM and reveal the molecular determinants of LdcI polymerization, confirmed by mutational analysis. Finally, we propose a model for LdcI function inside the enterobacterial cell, providing a structural and mechanistic basis for further investigation of the role of its supramolecular organization in the acid stress response.

Comparative Analysis of Acid Resistance between Susceptible and Multi-Antimicrobial-Resistant Salmonella Strains Cultured under Stationary-Phase Acid Tolerance–Inducing and Noninducing Conditions

2003 ◽  
Vol 66 (5) ◽  
pp. 732-740 ◽  
Author(s):  
R. T. BACON ◽  
J. N. SOFOS ◽  
P. A. KENDALL ◽  
K. E. BELK ◽  
G. C. SMITH
Keyword(s):  
Stationary Phase ◽  
Antimicrobial Agents ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Acid Resistance ◽  
Low Ph ◽  
Acid Exposure ◽  
Acid Adaptation ◽  
Acid Shock ◽  
Resistant Strains

This study compared acid resistance levels among five antimicrobial-susceptible strains of Salmonella and five strains that were simultaneously resistant to a minimum of six antimicrobial agents. The induction of a stationary-phase acid tolerance response (ATR) was attempted by both transient low-pH acid shock and acid adaptation. For acid shock induction, strains were grown for 18 h in minimal E medium containing 0.4% glucose (EG medium) and exposed to sublethal acid stress (pH 4.3) for 2 h, and subsequently, both shocked and nonshocked cultures were acid challenged (pH 3.0) for 4 h. Acid adaptation was achieved by growing strains for 18 h in tryptic soy broth containing 1.0% glucose (TSB+G), while nonadapted cultures were grown for 18 h in glucose-free tryptic soy broth (TSB−G). Acid-adapted and nonadapted inocula were acid challenged (pH 2.3) for 4 h. Initial (0 h) mean populations of nonchallenged Salmonella were 8.5 to 8.7, 8.4 to 8.8, and 8.2 to 8.3 log CFU/ml for strains grown in EG medium, TSB−G, and TSB+G, respectively. After 4 h of acid challenge, mean populations were 3.0 to 4.8 and 2.5 to 3.7 log CFU/ml for previously acid-shocked susceptible and resistant strains, respectively, while corresponding counts for nonshocked strains were 4.3 to 5.5 log CFU/ml and 3.9 to 4.9 log CFU/ml. Following 4 h of acid exposure, acid-adapted cultures of susceptible and resistant strains had mean populations of 6.1 to 6.4 log CFU/ml and 6.4 to 6.6 log CFU/ml, respectively, while corresponding counts for nonadapted cultures were 1.9 to 2.1 log CFU/ml and 1.8 to 2.0 log CFU/ml, respectively. A low-pH–inducible ATR was not achieved through transient acid shock, while an ATR was evident following acid adaptation, as adapted populations were 4.2 to 4.8 log units larger than nonadapted populations following acid exposure. Although some strain-dependent variations in acid resistance were observed, results from this study suggest no association between susceptibility to antimicrobial agents and the ability of the Salmonella strains evaluated to survive low-pH stress.

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.

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.

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