Adsorption of Poliovirus 1 and F+ Bacteriophages onto Sand

1993 ◽  
Vol 27 (7-8) ◽  
pp. 331-338 ◽  
Author(s):  
A. M. Nasser ◽  
A. Adin ◽  
B. Fattal
Keyword(s):  
Alkaline Ph ◽  
Virus Removal ◽  
Ph Values ◽  
Water Composition ◽  
Virus Adsorption ◽  
Influence Of Water ◽  
Adsorption Processes ◽  
Pathogenic Viruses ◽  
Trivalent Cations ◽  
Study Support

This study was performed to determine the influence of water composition, virus type, pH and various salts and their concentration on the adsorption of F+bacteriophages and poliovirus to sand. Virus adsorption to sand was greater at acidic than alkaline pH values. At alkaline values (8.0, 9.0) virus adsorption was poor particularly in distilled water. The presence of divalent and trivalent cations in the medium enhanced the virus adsorption appreciably. On the other hand, the presence of humic acid at 10 and 100 mg/l reduced virus adsorption onto sand. The rate of F+bacteriophage adsorption to sand was similar or lower than that of poliovirus 1. Therefore, F+bacteriophages removal by adsorption processes is expected to be at similar or lower rates than that of pathogenic viruses. The results of this study support the initiative of proposing F+bacteriophages as anindex for virus removal through sand filtration.

scholarly journals Influence of Salts on Virus Adsorption to Microporous Filters

2000 ◽  
Vol 66 (7) ◽  
pp. 2914-2920 ◽  
Author(s):  
Jerzy Lukasik ◽  
Troy M. Scott ◽  
Diane Andryshak ◽  
Samuel R. Farrah
Keyword(s):  
Aluminum Chloride ◽  
Indirect Effects ◽  
Hydrophobic Interactions ◽  
Tween 80 ◽  
Direct Effects ◽  
Virus Removal ◽  
Ph Values ◽  
Virus Adsorption ◽  
Enhanced Adsorption ◽  
Viral Adsorption

ABSTRACT We investigated the direct and indirect effects of mono-, di-, and trivalent salts (NaCl, MgCl2, and AlCl3) on the adsorption of several viruses (MS2, PRD-1, φX174, and poliovirus 1) to microporous filters at different pH values. The filters studied included Millipore HA (nitrocellulose), Filterite (fiberglass), Whatman (cellulose), and 1MDS (charged-modified fiber) filters. Each of these filters except the Whatman cellulose filters has been used in virus removal and recovery procedures. The direct effects of added salts were considered to be the effects associated with the presence of the soluble salts. The indirect effects of the added salts were considered to be (i) changes in the pH values of solutions and (ii) the formation of insoluble precipitates that could adsorb viruses and be removed by filtration. When direct effects alone were considered, the salts used in this study promoted virus adsorption, interfered with virus adsorption, or had little or no effect on virus adsorption, depending on the filter, the virus, and the salt. Although we were able to confirm previous reports that the addition of aluminum chloride to water enhances virus adsorption to microporous filters, we found that the enhanced adsorption was associated with indirect effects rather than direct effects. The increase in viral adsorption observed when aluminum chloride was added to water was related to the decrease in the pH of the water. Similar results could be obtained by adding HCl. The increased adsorption of viruses in water at pH 7 following addition of aluminum chloride was probably due to flocculation of aluminum, since removal of flocs by filtration greatly reduced the enhancement observed. The only direct effect of aluminum chloride on virus adsorption that we observed was interference with adsorption to microporous filters. Under conditions under which hydrophobic interactions were minimal, aluminum chloride interfered with virus adsorption to Millipore, Filterite, and 1MDS filters. In most cases, less than 10% of the viruses adsorbed to filters in the presence of a multivalent salt and a compound that interfered with hydrophobic interactions (0.1% Tween 80 or 4 M urea).

scholarly journals Effect of alkaline pH on photosynthetic water oxidation and the association of extrinsic proteins with Photosystem Two

1989 ◽  
Vol 258 (2) ◽  
pp. 357-362 ◽  
Author(s):  
D J Chapman ◽  
J De Felice ◽  
K Davis ◽  
J Barber
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Binding Sites ◽  
Partial Recovery ◽  
Alkaline Ph ◽  
Ph Values ◽  
Extrinsic Proteins ◽  
Reversible Phase ◽  
Photosynthetic Water Oxidation ◽  
Optimal Ph

Incubation of a membrane preparation enriched in Photosystem Two (PSII) at alkaline pH inhibited the water-splitting reactions in two distinct steps. Up to pH 8.5 the inhibition was reversible, whereas at higher alkalinities it was irreversible. It was shown that the reversible phase correlated with loss and rebinding of the 23 kDa extrinsic polypeptide. However, after mild alkaline treatments a partial recovery was possible without the binding of the 23 kDa polypeptide when the assay was at the optimal pH of 6.5 and in a medium containing excess Cl-. The irreversible phase was found to be closely linked with the removal of the 33 kDa extrinsic protein of PSII. Treatments with pH values above 8.5 not only caused the 33 kDa protein to be displaced from the PSII-enriched membranes, but also resulted in an irreversible modification of the binding sites such that the extrinsic 33 kDa protein could not reassociate with PSII when the pH was lowered to 6.5. The results obtained with these more extreme alkaline pH treatments support the notion that the 23 kDa protein cannot bind to PSII unless the 33 kDa protein is already bound. The differential effect of pH on the removal of the 23 kDa and 33 kDa proteins contrasted with the data of Kuwabara & Murata [(1983) Plant Cell Physiol. 24, 741-747], but this discrepancy was accounted for by the use of glycerol in the incubation media.

Proteins recovered from milks heated at alkaline pH values

1987 ◽  
Vol 40 (4) ◽  
pp. 82-85 ◽  
Author(s):  
M B GRUFFERTY ◽  
D M MULVIHILL
Keyword(s):  
Alkaline Ph ◽  
Ph Values

scholarly journals Geochemistry of natural waters of the Baydar valley (Crimean Peninsula)

2019 ◽  
Vol 98 ◽  
pp. 01036
Author(s):  
Larisa A. Nichkova ◽  
Dmitry A. Novikov ◽  
Anatoliy V. Chernykh ◽  
Fedor F. Dultsev ◽  
Galina A. Sigora ◽  
...  
Keyword(s):  
Trace Elements ◽  
Surface Waters ◽  
Natural Waters ◽  
Upper Jurassic ◽  
Alkaline Ph ◽  
Crimean Peninsula ◽  
Ph Values ◽  
Ree Distribution ◽  
Basic Characteristics ◽  
The Crimean Peninsula

The paper discusses the pioneering results of comprehensive hydrogeochemical studies of natural waters of the Baydar valley (southwestern parts of the Crimean Peninsula), whose major aquifers are confined to the upper Jurassic sediments (karst limestone) representing the most important hydrogeological feature of the study area. Fresh and ultra-fresh waters of predominantly bicarbonate calcium composition with total mineralization in the range from 194 to 1137 mg/dm3 are most widespread in the region. The analyzed waters (surface, ground and artesian) differ significantly in chemical composition and their basic characteristics have been arranged in the following patterns: mineralization of 254-832 mg/dm3 and neutral pH (6.98-7.54) for artesian waters; higher mineralization level (up to 1137 mg/dm3) and wide variations of pH values (from 7.18 to 8.31) for ground waters; mineralization from 194 to 288 mg/dm3 and a slightly alkaline pH (between 8.02 and 8.04) for surface waters collected in the Chyornaya river basin and Chernorechensk reservoir. The studied waters display a unique spectrum of trace elements and REE distribution.

scholarly journals Geochemical Modeling of Iron and Aluminum Precipitation during Mixing and Neutralization of Acid Mine Drainage

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 547 ◽  
Author(s):  
Darrell Kirk Nordstrom
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Geochemical Modeling ◽  
Lime Treatment ◽  
Mixing Processes ◽  
Ph Values ◽  
Acid Mine ◽  
Water Composition ◽  
Slaked Lime ◽  
Best Fit

Geochemical modeling of precipitation reactions in the complex matrix of acid mine drainage is fundamental to understanding natural attenuation, lime treatment, and treatment procedures that separate constituents for potential reuse or recycling. The three main dissolved constituents in acid mine drainage are iron, aluminum, and sulfate. During the neutralization of acid mine drainage (AMD) by mixing with clean tributaries or by titration with a base such as sodium hydroxide or slaked lime, Ca(OH)2, iron precipitates at pH values of 2–3 if oxidized and aluminum precipitates at pH values of 4–5 and both processes buffer the pH during precipitation. Mixing processes were simulated using the ion-association model in the PHREEQC code. The results are sensitive to the solubility product constant (Ksp) used for the precipitating phases. A field example with data on discharge and water composition of AMD before and after mixing along with massive precipitation of an aluminum phase is simulated and shows that there is an optimal Ksp to give the best fit to the measured data. Best fit is defined when the predicted water composition after mixing and precipitation matches most closely the measured water chemistry. Slight adjustment to the proportion of stream discharges does not give a better fit.

scholarly journals In Vitro Alkaline pH Resistance of Enterococcus faecalis

2013 ◽  
Vol 24 (5) ◽  
pp. 474-476 ◽  
Author(s):  
Paulo Henrique Weckwerth ◽  
Ronald Ordinola Zapata ◽  
Rodrigo Ricci Vivan ◽  
Mário Tanomaru Filho ◽  
Amanda Garcia Alves Maliza ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Enterococcus Faecalis ◽  
Bacterial Species ◽  
Clinical Isolates ◽  
Bacterial Suspension ◽  
Alkaline Ph ◽  
Root Canals ◽  
Ph Values ◽  
Positive Controls

Enterococcus faecalis is a bacterial species often found in root canals with failed endodontic treatment. Alkaline pastes are widely used in Endodontics because of their biocompatibility and antimicrobial activity, but this microorganism can resist alkalinity. The purpose of this study was to evaluate in vitro the alkaline pH resistance of E. faecalis for different periods up to 14 days. Samples were obtained from the oral cavity of 150 patients from the Endodontic clinic. The pH of the experimental tubes (n=84) was first adjusted with 6M NaOH to pH values of 9.5, 10.5, 11.5 and 12.5 (21 tubes per pH). Twenty clinical isolates and the ATCC 29212 strain were tested. The 5 positive controls and experimental tubes of each pH were inoculated with 10 µL of bacterial suspension and incubated at 36 °C for 24, 48 and 72 h, 7 and 14 days. For each period, the turbidity of the medium was visually compared with a 0.5 McFarland standard. The presence of the microorganism was confirmed by seeding on M-Enterococcus agar. Four tubes containing BHI broth adjusted to the tested pHs were incubated for 14 days to verify if pH changes occurred. The pH of inoculated BHI broth was also measured on day 14 to determine if the microorganism acidified the medium. The growth of all E. faecalis strains occurred at pH 9.5 to 11.5 in all periods. Although turbidity was not observed at pH 12.5, there was growth of 13 and 2 strains at 24 and 48 h, respectively, on M-Enterococcus agar. No tube showed growth at pH 12.5 after 72 h. It was concluded that E. faecalis can survive in highly alkaline pH, and some clinical isolates require 72 h at pH 12.5 to be killed.

scholarly journals PHR2 of Candida albicans encodes a functional homolog of the pH-regulated gene PHR1 with an inverted pattern of pH-dependent expression.

1997 ◽  
Vol 17 (10) ◽  
pp. 5960-5967 ◽  
Author(s):  
F A Mühlschlegel ◽  
W A Fonzi
Keyword(s):  
Candida Albicans ◽  
Mutant Strain ◽  
Low Ph ◽  
Predicted Amino Acid Sequence ◽  
Acidic Ph ◽  
Null Mutant ◽  
Alkaline Ph ◽  
Ph Values ◽  
Functional Homolog ◽  
Morphological Defects

Deletion of PHR1, a pH-regulated gene of Candida albicans, results in pH-conditional defects in growth, morphogenesis, and virulence evident at neutral to alkaline pH but absent at acidic pH. Consequently, we searched for a functional homolog of PHR1 active at low pH. This resulted in the isolation of a second pH-regulated gene, designated PHR2. The expression of PHR2 was inversely related to that of PHR1, being repressed at pH values above 6 and progressively induced at more acidic pH values. The predicted amino acid sequence of the PHR2 protein, Phr2p, was 54% identical to that of Phr1p. A PHR2 null mutant exhibited pH-conditional defects in growth and morphogenesis analogous to those of PHR1 mutants but manifest at acid rather than alkaline pH values. Engineered expression of PHR1 at acid pH in a PHR2 mutant strain and PHR2 at alkaline pH in a PHR1 mutant strain complemented the defects in the opposing mutant. Deletion of both PHR1 and PHR2 resulted in a strain with pH-independent, constitutive growth and morphological defects. These results indicate that PHR1 and PHR2 represent a novel pH-balanced system of functional homologs required for C. albicans to adapt to environments of diverse pH.

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