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.

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.

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.

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