The distribution of scaled chrysophytes along a pH gradient

1989 ◽  
Vol 67 (7) ◽  
pp. 2120-2130 ◽  
Author(s):  
Peter A. Siver
Keyword(s):  
Acid Deposition ◽  
Significant Decline ◽  
Water Bodies ◽  
Ph Gradient ◽  
Weighted Mean ◽  
Scaled Chrysophytes ◽  
Frequency Distributions ◽  
Ph Values ◽  
Adirondack Lakes ◽  
Acidic Conditions

Frequency distributions versus pH and weighted mean pH values are reported for 25 and 40 species of scaled chrysophytes, from water bodies in Connecticut and the Adirondacks, respectively, and are compared with those assembled from a survey of the literature. For most species, similar distributions with respect to a pH gradient and weighted mean pH values were found. However, in Connecticut and Adirondack lakes, Mallomonas punctifera and Synura spinosa were more restricted to slightly acidic conditions and M. hamata was more abundant in conditions below a pH of 5.5. Groups of taxa with similar distributions with respect to pH were clearly defined. One group, consisting of Mallomonas acaroides var. muskokana, M. paludosa, M. pugio, M. canina, M. hindonii, S. sphagnicola, and S. echinulata, was dominant in waters with a pH < 5.5. Another group, including M. acaroides var. acaroides, M. corymbosa, M. tonsurata, M. psuedocoronata, and M. alpina, was primarily restricted to pH values above 6.5. A third group, including M. punctifera, M. akrokomas, M. crassisquama, M. galeiformis, M. caudata, Spiniferomonas bourrellyi, Sp. serrata, S. spinosa, and Chrysosphaerella longispina, had a significant decline in occurrence as the pH lowered to the 5–5.5 interval. The importance of scaled chrysophytes as a group in the biomonitoring of acid deposition is discussed.

When Did Acid-Sensitive Adirondack Lakes (New York, USA) Begin to Acidify and Are They Still Acidifying?

1994 ◽  
Vol 51 (7) ◽  
pp. 1550-1568 ◽  
Author(s):  
B. F. Cumming ◽  
K. A. Davey ◽  
J. P. Smol ◽  
H. J. B. Birks
Keyword(s):  
New York ◽  
Transfer Function ◽  
Species Composition ◽  
Acidic Deposition ◽  
Sediment Cores ◽  
Scaled Chrysophytes ◽  
Sulfate Deposition ◽  
Ph Values ◽  
Water Ph ◽  
Adirondack Lakes

A transfer function was used to reconstruct pH values of 20 low-alkalinity Adirondack Park lakes based on the species composition of scaled chrysophytes (Chrysophyceae, Synurophyceae) in stratigraphie intervals from 210Pb-dated sediment cores. Approximately 80% of the lakes acidified since preindustrial times. Four categories of lake response to acidic deposition were identified: (i) lakes that showed little or no evidence of acidification since preindustrial times, (ii) lakes with preindustrial pH values between 5 and 6 that began to acidify ca. 1900, (iii) "naturally" acidic lakes that acidified even further ca. 1900, and (iv) lakes with preindustrial pH values around 6 that acidified ca. 1930–50. Lakes that acidified ca. 1900 were generally smaller, higher elevation lakes with lower preindustrial pH values than lakes in category i or iv. These patterns are consistent with the acidic deposition hypothesis of recent lake acidification. Our results indicated that "critical" sulfate deposition loads for Adirondack lakes that started to acidify ca. 1900 and ca. 1950 are between 5–10 and 20–25 kg∙ha−1∙yr−1, respectively. Post-1970 trends in lake water pH have been small and variable, suggesting that low-alkalinity Adirondack lakes have been relatively unresponsive to the post-1970 declines in sulfate deposition.

Removal of Dyes from Aqueous Solutions by Adsorption on Chrome-Tanned Solid Wastes Generated in the Leather Industry

2003 ◽  
Vol 38 (2) ◽  
pp. 393-411 ◽  
Author(s):  
Soufiane Tahiri ◽  
Ali Messaoudi ◽  
Abderrahman Albizane ◽  
Mohamed Azzi ◽  
Mohamed Bouhria ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Operating Conditions ◽  
Solid Wastes ◽  
Cationic Dyes ◽  
Optimum Operating ◽  
Leather Industry ◽  
Anionic Dyes ◽  
Ph Values ◽  
Acidic Conditions ◽  
Dyes Adsorption

Abstract In this work, the ability of chrome shavings and of crust leather buffing dusts to remove dyes from aqueous solutions has been studied. Buffing dusts proved to be a much better adsorbent than chrome shavings for cationic dyes. The adsorption of anionic dyes is very important on two studied wastes. The pH has an obvious influence on the adsorption of dyes. Adsorption of cationic dyes is less favourable under acidic conditions (pH &lt;3.5) and at high pH values (pH &gt;10.5). The adsorption of anionic dyes on both adsorbents is more favourable under acidic conditions (pH &lt;3). The adsorption on chrome shavings is improved by the use of finer particles. The kinetic adsorption was also studied. Adsorption isotherms, at the optimum operating conditions, were determined. Adsorption follows the Langmuir model. The isotherm parameters have been calculated. The column technique could be applied to treat significant volumes of solutions.

Resistance of Acid-Adapted Salmonellae to Organic Acid Rinses on Beef†

1995 ◽  
Vol 58 (9) ◽  
pp. 973-976 ◽  
Author(s):  
J. S. DICKSON ◽  
M. R. KUNDURU
Keyword(s):  
Organic Acid ◽  
Parent Strain ◽  
Good Growth ◽  
Acid Solutions ◽  
Bacterial Populations ◽  
Acid Adaptation ◽  
Ph Values ◽  
Atcc Strain ◽  
Lean Beef ◽  
Acidic Conditions

Four strains of salmonellae, including three bovine isolates and an ATCC strain, were adapted to growth in acidic conditions by sequential transfer in tryptic soy broth with reduced pH values. The cultures were transferred until good growth (approximately log107 CFU/ml) was obtained within 24 h at 37°C at pH 5.0. Lean beef tissue was inoculated by immersion into either the acid-adapted or the homologous parent strain of each bacterium. The inoculated tissue was rinsed for 10s in 1.5% or 3.0% lactic acid solutions at 23°C or 55°C. Reductions in bacterial populations were compared between the parent and acid-adapted strains to determine if the acid-adapted strains were more resistant to the organic acid rinses. Acid-adapted strains had either equal or greater sensitivity to organic acid rinses than their homologous parent strains, indicating that acid adaptation did not result in bacteria which were resistant to organic acid rinses. Acid-adapted strains had significantly lower D55°C− values than their homologous parent strains.

Transmural pH gradient in canine myocardial ischemia

1984 ◽  
Vol 246 (2) ◽  
pp. H232-H238 ◽  
Author(s):  
R. M. Watson ◽  
D. R. Markle ◽  
Y. M. Ro ◽  
S. R. Goldstein ◽  
D. A. McGuire ◽  
...  
Keyword(s):  
Blood Flow ◽  
Myocardial Ischemia ◽  
Coronary Stenosis ◽  
Fiber Optic ◽  
Acute Myocardial Ischemia ◽  
Ph Gradient ◽  
Ph Values ◽  
Probe System ◽  
Ph Probes ◽  
Transmural Gradient

The subendocardium is more susceptible to ischemia than the subepicardium. Studies during critical coronary stenosis have demonstrated subendocardial hypoperfusion relative to the subepicardium and transmural gradients in certain tissue metabolites. Although ischemia causes acidosis, the existence of a transmural pH gradient has never been demonstrated or quantitated. Thus we reduced coronary blood flow to 20 +/- 5% of normal in eight open chest anesthetized (morphine sulfate and pentobarbital) dogs and to 45 +/- 5% in two dogs. We implanted specially designed miniature fiber-optic pH probes in normal and ischemic subendocardium (depth 5.5-8 mm) and subepicardium (depth 3-4 mm). Separate experiments validated use of the fiber-optic pH probe system to measure tissue pH. Although both probes were located in the ischemic zone, there was a large transmural gradient, i.e., from normal pH values (7.36) in the subepicardium to severely acidotic (pH 6.94) 2 mm deeper in the subendocardium. This marked difference in pH between nearby transmural layers may have important implications regarding arrhythmogenesis in the setting of acute myocardial ischemia.

scholarly journals Large Differences in Urinary Benzene Metabolite S-Phenylmercapturic Acid Quantitation: A Comparison of Five LC–MS-MS Methods

2020 ◽  
Author(s):  
Denise S Tevis ◽  
Andrew Willmore ◽  
Deepak Bhandari ◽  
Brett Bowman ◽  
Chloe Biren ◽  
...  
Keyword(s):  
Human Urine ◽  
Analytical Methods ◽  
Urine Samples ◽  
Genotoxic Carcinogen ◽  
Human Urine Samples ◽  
Ph Values ◽  
Wide Range ◽  
Acidic Conditions ◽  
Hematological Abnormalities ◽  
Reference Samples

Abstract Benzene is a known genotoxic carcinogen linked to many hematological abnormalities. S-phenylmercapturic acid (PHMA, N-acetyl-S-(phenyl)-L-cysteine, CAS# 4775-80-8) is a urinary metabolite of benzene and is used as a biomarker to assess benzene exposure. Pre-S-phenylmercapturic acid (pre-PHMA) is a PHMA precursor that dehydrates to PHMA at acidic pH. Published analytical methods that measure urinary PHMA adjust urine samples to a wide range of pH values using several types of acid, potentially leading to highly variable results depending on the concentration of pre-PHMA in a sample. Information is lacking on the variation in sample preparation among laboratories regularly measuring PHMA and the effect of those differences on PHMA quantitation in human urine samples. To investigate the differences in PHMA quantitation, we conducted an inter-laboratory comparison that included the analysis of 50 anonymous human urine samples (25 self-identified smokers and 25 self-identified non-smokers), quality control samples and commercially available reference samples in five laboratories using different analytical methods. Observed urinary PHMA concentrations were proportionally higher at lower pH, and results for anonymous urine samples varied widely among the methods. The method with the neutral preparation pH yielded results about 60% lower than the method using the most acidic conditions. Samples spiked with PHMA showed little variation, suggesting that the variability in results in human urine samples across methods is driven by the acid-mediated conversion of pre-PHMA to PHMA.

Distribution of scaled chrysophytes in 17 Adirondack (New York) lakes with special reference to pH

1988 ◽  
Vol 66 (7) ◽  
pp. 1391-1403 ◽  
Author(s):  
Peter A. Siver
Keyword(s):  
New York ◽  
Special Reference ◽  
Surface Sediments ◽  
Species Distributions ◽  
Franklin County ◽  
Scaled Chrysophytes ◽  
Bog Lakes ◽  
Adirondack Lakes ◽  
The Common ◽  
Similarities And Differences

Thirty-four scaled chrysophyte taxa are described from 17 Adirondack lakes located in either Hamilton or Franklin counties. Ten taxa, Synura sphagnicola, Syn. echinulata, Syn. petersenii, Mallomonas acaroides var. muskokana, M. hamata, M. caudata, M. crassisquama, M. galeiformis, Spiniferomonas trioralis, and Chrysosphaerella longispina, were found in more than 40% of the study lakes. Mallomonas acaroides var. muskokana, M. hamata, Syn. sphagnicola, Syn. echinulata, and Spiniferomonas coronacircumspina were common and important components of the phytoplankton floras in lakes with a pH < 5.4; however, M. hamata and Sp. coronacircumspina were noticeably absent from bog lakes. Synura sphagnicola and Syn. echinulata were as common in samples with a pH between 5.4 and 7 as they were below pH 5.4. Mallomonas crassisquama, M. caudata, M. pseudocoronata, and Synura spinosa were found in a significantly greater percentage of samples from circumneutral lakes and were lacking from waters with a pH < 5.4. Differences in species distributions between Hamilton County (higher mean pH) and Franklin County lakes further supported the observed pH ranges of the common taxa. Similarities and differences are made with a study of Smol et al. (Can. J. Bot. 62: 911–923), who described the distribution of scaled chrysophytes from the surface sediments of Adirondack lakes.

Heat Resistance of Alicyclobacillus acidoterrestris Spores as Affected by Various pH Values and Organic Acids‡

1998 ◽  
Vol 61 (1) ◽  
pp. 41-46 ◽  
Author(s):  
APRIL J. PONTIUS ◽  
JOHN E. RUSHING ◽  
PEGGY M. FOEGEDING
Keyword(s):  
Heat Resistance ◽  
Fruit Juice ◽  
Ion Concentration ◽  
Thermal Processes ◽  
Alicyclobacillus Acidoterrestris ◽  
Hydrogen Ion Concentration ◽  
Ph Values ◽  
Acid Type ◽  
Acidic Conditions ◽  
D Values

Alicyclobacillus acidoterrestris, a thermoacidophilic sporeformer, has caused spoilage of fruit juices which had been treated with thermal processes intended to commercially sterilize the juice. The objective of this research was to document the effect of pH, acid, and temperature on the heat resistance of spores of three fruit-juice isolates of A. acidoterrestris. The thermal resistance of spores of A. acidoterrestris strains VF, WAC, and IP were studied in a model fruit-juice system composed of 12% glucose and 30 mM of either citric, malic, or tartaric acid, adjusted to selected pH values ranging from 2.8 to 4.0. Decimal reduction times (D values) and inactivation rates were determined. Spores of strains VF and WAC were similarly resistant to heat under acidic conditions, while strain IP spores were less resistant. In the range of pH 2.8 to 4.0, a statistically significant effect of hydrogen ion concentration on heat resistance was observed at lower temperatures, but not at the higher temperatures. For example, at 91 °C and pH 3.1 and 3.7, D values were 31.3 and 54.3 min, respectively, while at 97°C D values at pH 3.1 and 3.7 were 7.9 and 8.8 min, respectively. The type of acid did not significantly affect the heat resistance. The zD values ranged from 5.9 to 10°C, depending on the acid, pH, and the strain. The models generated from this research can be used to determine adequate thermal processes, accounting for the acid type, pH, and temperature, to destroy A. acidoterrestris spores in beverages, since this organism is able to survive the typical hot-fill and hold process (2 min at 88 to 96°C) currently used to process fruit juice.

scholarly journals Survival of Probiotic Lactobacilli in Acidic Environments Is Enhanced in the Presence of Metabolizable Sugars

2005 ◽  
Vol 71 (6) ◽  
pp. 3060-3067 ◽  
Author(s):  
B. M. Corcoran ◽  
C. Stanton ◽  
G. F. Fitzgerald ◽  
R. P. Ross
Keyword(s):  
Gastric Juice ◽  
Lactobacillus Rhamnosus ◽  
Probiotic Strain ◽  
Iodoacetic Acid ◽  
Glucose Effect ◽  
Ph Values ◽  
Gapdh Activity ◽  
Acidic Conditions ◽  
Probiotic Lactobacilli ◽  
Effect Of Glucose

ABSTRACT Lactobacillus rhamnosus GG is an industrially significant probiotic strain with proven health benefits. In this study, the effect of glucose on L. rhamnosus GG survival was analyzed in simulated gastric juice at pH 2.0. It was found that the presence of 19.4 mM glucose resulted in up to 6-log10-enhanced survival following 90 min of exposure. Further work with dilute HCl confirmed that glucose was the sole component responsible. Comparative analysis with other Lactobacillus strains revealed that enhanced survival was apparent in all strains, but at different pH values. The presence of glucose at concentrations from 1 to 19.4 mM enhanced L. rhamnosus GG survival from 6.4 to 8 log10 CFU ml−1 in simulated gastric juice. The mechanisms behind the protective effect of glucose were investigated. Addition of N′,N′-dicyclohexylcarbodiimide to simulated gastric juice caused survival to collapse, which was indicative of a prominent role in inhibition of F0F1-ATPase. Further work with neomycin-resistant mutants that exhibited 38% to 48% of the F0F1-ATPase activity of the parent confirmed this, as the survival in the presence of glucose of these mutants decreased 3 × 106-fold compared with the survival of the wild type (which had a viability of 8.02 log10 CFU ml−1). L. rhamnosus GG survival in acidic conditions occurred only in the presence of sugars that it could metabolize efficiently. To confirm the involvement of glycolysis in the glucose effect, iodoacetic acid was used to inhibit glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity. The reduction in GAPDH activity caused survival to decrease by 8.30 log10 CFU ml−1 in the presence of glucose. The data indicate that glucose provides ATP to F0F1-ATPase via glycolysis, enabling proton exclusion and thereby enhancing survival during gastric transit.

Use of Extant Populations of Scaled Chrysophytes for the Inference of Lakewater pH

1990 ◽  
Vol 47 (7) ◽  
pp. 1339-1347 ◽  
Author(s):  
Peter A. Siver ◽  
Josephine S. Hamer
Keyword(s):  
Indicator Organisms ◽  
Weighted Mean ◽  
Scaled Chrysophytes ◽  
Inference Models ◽  
Discrete Sample ◽  
Analysis Technique ◽  
Cluster Analysis Technique ◽  
Multiple Samples ◽  
Term Monitoring

Abundance of living populations of scaled chrysophytes were used to develop multiple regression models for inferring lakewater pH. Until now, all such inference models had been prepared with surface sediment remains and used to reconstruct historical (down-core) changes. We demonstrate that highly significant models can be prepared from living populations of scaled-chrysophytes which could be valuable for monitoring chronic, episodic and/or long-term changes in lakewater pH. Average weighted-mean pH and a cluster analysis technique were used to divide 33 taxa found in 26 Connecticut lakes into groups according to their distribution along a pH gradient. Two calculations of average weighted-mean pH were made; one based on data from this study and one from literature records. Inference models were developed using a single sample from each lake as well as for multiple samples collected throughout the year. The best model based on a single discrete sample yielded an R2 = 0.58 (p < 0.05); multiple samples from each lake yielded significantly higher R2 values, (between 0.75 and 0.83). Scaled chrysophytes appear to be a very valuable assemblage of indicator organisms for the long-term monitoring of lakes.

scholarly journals Degradation of Oxytetracycline By Magnetic MOFs Heterojunction Photocatalyst With Persulfate : High Stability And Wide Range

2021 ◽  
Author(s):  
Zhuo Zhang ◽  
Chunyan Du ◽  
Yin Zhang ◽  
Guanlong Yu ◽  
Ying Xiong ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Removal Efficiency ◽  
Organic Pollutants ◽  
High Stability ◽  
Water Bodies ◽  
Significant Implication ◽  
Ph Values ◽  
Wide Range ◽  
Excellent Stability

Abstract Photocatalysis/Persulfate is an effective method of degrading organic pollutants. In this study, Fe3O4/MIL-101(Fe), a magnetic heterojunction photocatalyst, was produced by hydrothermal method. The material exhibited excellent removal efficiency for OTC in the coupling of persulfate (87.1%, 1 h). And it has a wide range of applications, with good removal efficiency for OTC concentrations of 30 to 70 mg/L and pH values of 3 to 9. •SO4− and •OH played a major role in the OTC removal reaction and there was an Fe(III)/Fe(II) cycle during the reaction. With excellent stability and recoverability, the OTC removal efficiency decreased by only 4.29% after four cycles, and the Fe leaching did not exceed 0.035 mg/L per cycle. This has a significant implication for the removal of organic pollutants from water bodies.

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