Zinc Acetate Precipitation Research Articles

Comparing solid-based concentration methods for rapid and efficient recovery of SARS-CoV-2 for wastewater surveillance

As wastewater-based surveillance of SARS-CoV-2 attracts interest globally, there is a need to evaluate and identify rapid and efficient methods for concentrating enveloped viruses in wastewater. When comparing five precipitation/flocculation-based concentration methods (including aluminum hydroxide adsorption-precipitation, AHAP; zinc acetate precipitation, ZAP; skimmed milk flocculation, SMF; FeCl3 precipitation, FCP; and direct centrifugation, DC), AHAP was found to be the most efficient method in terms of seeded BCoV recovery (50.2 %). Based on the BCoV recovery efficiency and turnaround time, the AHAP and DC methods were selected and tested on five additional wastewater samples containing both seeded BCoV and indigenous wastewater SARS-CoV-2 RNA. The BCoV recovery (DC: average=30.1 %, sx =14.7 %; AHAP: average=33.0 %, sx =14.2 %) and SARS-CoV-2 based on the N2 gene assay (DC: average=3.6 ×103 gene copies or GC/mL, sx =1.9 × 103 GC/mL; AHAP: average=3.0 ×103 GC/mL, sx =2.0 ×103 GC/mL) of both methods were not significantly different in solid fraction (p = 0.89). This study showed significant higher BCoV recovery and SARS-CoV-2 viral RNA in wastewater solid fraction (p = 0.006) than liquid fraction. Our result suggests that the solid fraction of wastewater samples is more suitable for recovering enveloped viruses from wastewater, and the DC and AHAP methods equally provide suitably rapid, cost-effective, and significantly higher recovery of SARS-CoV-2 viral RNA in wastewater samples.

Interference Elimination of Sulfide Determination by Iodometry

As a classical method for sulfide determination in wastewater, iodimetry is adopted by many countries. But the existing of high concentration of reducing materials such as thiosulfate, sulfite and dissolved organic, which cant be eliminated by the pretreatment of zinc acetate-precipitation filtration, have an important influence on determination. The study on elimination method is carried out in this paper. It is indicated that the interference of S2O32-and SO32-can be eliminated by washing sedimentation with KOH solution of 10%. Iodometric titration with the pretreatment of zinc acetate-precipitation filtration and washing precipitate with 10% KOH is an accurate method to determine the sulfide content.

Separation of IgG and IgM from albumin in citrated human plasma using electrodialysis and metal ion affinity precipitation.

Plasmapheresis is the process by which plasma is separated from whole blood for therapeutic purposes. The primary reason to perform plasmapheresis is to remove immunoglobulins and not to necessarily remove the remainder of the plasma proteins. Nevertheless, most plasmapheresis is performed by centrifugal separation to remove bulk plasma. We have investigated whether electrodialysis and metal ion affinity precipitation can be used to selectively remove immunoglobulins from citrated plasma and potentially serve as an adjunctive technique to centrifugal plasmapheresis. Using a commercial electrodialysis device, we have desalted citrated plasma to separate immunoglobulins from albumin, and have determined the effects of pH adjustment and addition of zinc acetate for concomitant metal ion affinity precipitation. With desalted pH adjusted citrated plasma containing 1.5 mM zinc acetate, we achieved more than 80% recovery of albumin with removal of almost 60% of the immunoglobulin (Ig)G. Almost 80% of polyclonal IgM and 90% of monoclonal IgM was also removed. IgA was not effectively removed under any of the conditions tested. Selective precipitation with electrodialysis and zinc acetate precipitation appears to be an effective technique for the separation of IgG and IgM from albumin in citrated plasma.

Purification of chick interferon by zinc chelate affinity chromatography and sodium dodecylsulfate-polyacrylamide gel electrophoresis.

An improved purification method for chick interferon from the allantoic fluid of embryonated chick eggs is described. Interferon prepurified by perchloric acid treatment, zinc acetate precipitation, and chromatography on SP-Sephadex C-25 was further enriched by column chromatography on zinc chelate. Analysis on sodium dodecylsulfate polyacrylamide gel electrophoresis of the interferon preparation with a specific activity of 8 X 10(5) units/mg protein shows that the major antiviral activity migrated in a broad band in the range of 20-29 kD molecular weight. Several protein bands were stainable with Coomassie blue and silver nitrate in this molecular weight range. Between 80 and 95% of the total protein charged to the gel could be removed from the interferon containing fractions by sodium dodecylsulfate polyacrylamide gel electrophoresis.

Purification and Characterization of Mouse L Cell Interferon

ABSTRACTInterferon was produced in high yields in mouse L cell cultures infected with Newcastle disease virus, with a specific activity of the order of 106 units per mg protein. It was partially purified by zinc acetate precipitation, carboxymethyl Sephadex chromatography, Sephadex gel filtration and pressure dialysis. On electrophoresis in polyacrylamide gel, it consisted of a fast‐moving sharp component and a slow, broadly distributed component(s). The highest specific activity of the former component so far obtained was 8 × 107 units per mg protein, numerically the highest value ever reported for interferon. It was considered likely, however, that the protein components in the purified samples, revealed by staining of the electrophoresis gel, still represented mostly impurities. Gel filtration experiment indicated some heterogeneity of interferon in molecular weight but the major component was estimated to be 30 000 in molecular weight. Interferon activity could be maintained without added preservatives for prolonged periods, provided that the protein concentration of the sample itself was high. One interferon unit as defined in this paper was found to correspond to 0.3 international unit.

Recovery of Protective Activity in Rabies Virus Vaccines Concentrated and Purified by Four Different Methods

Rabies vaccines concentrated by ultrafiltration, zinc acetate precipitation, ammonium sulfate precipitation, or aluminum phosphate gel adsorption were compared with respect to recovery of protective activity and purity, as measured by protective activity per mg of protein. Vaccine obtained by ammonium sulfate precipitation had a better recovery rate and a higher purity than those prepared by the other methods. Potent vaccines were also obtained by the zinc acetate precipitation and aluminum phosphate gel adsorption methods, whereas ultrafiltration was the least satisfactory method from the standpoint of vaccine purity. Chromatography of virus concentrated by ultrafiltration on a cellulose ion exchange column reduced the level of nonviral proteins. The protective activity data obtained for the vaccines examined in these experiments were found to correlate with the vaccine's complement fixation titer per mg of protein.

Antigenic and Immunogenic Properties of Components Contained in Rabies Virus-Infected Tissue Culture Fluids

Abstract Following differential centrifugation or zinc acetate precipitation, it was possible to fractionate rabies-infected tissue culture fluids into components which exhibited different complement-fixing, protective and immunogenic activities. The virion-depleted fraction showed higher complement-fixing activity than the fraction which contained essentially all the virions. The virion-depleted fraction obtained after precipitation of the virus with zinc acetate showed, in addition to complement-fixing activity, good protective activity. Thus, it is possible to produce material which contains a minimum quantity of infectious virus, is immunogenic and induces protection against challenge with virulent virus.

Method of Purification and Properties of Anti-XIa (Inhibitor of the Contact Product)

Summary1. A normally occurring inhibitor (anti-XIa) of product XIa (contact product, activated PTA) was purified 100-fold by a combination of zinc acetate precipitation, anion exchange chromatography and starch block electrophoresis.2. The inhibitor was shown by electrophoresis to have the mobility of an alpha globulin. The purified inhibitor was free of antithrombin III activity and anti-XIIa activity. The anti-XIa fraction was free of coagulation factor activity and was stable over a wide range of pH and temperature. Analytical ultracentrifugation of a purified inhibitor fraction showed a symmetrical peak of S20w = 3.69.3. The inhibitor was not consumed during its interaction with product XIa.4. With the use of the purified inhibitor, the product XIa preparation used was shown to be practically free of precursor factor XI or XII activity.

Purification and separation of platelet factor 2 (Fibrinogen activating factor) and of platelet factor 4 (antiheparin factor)

A chromatographic method for the purification and separation of platelet factor 2 and of platelet factor 4 has been elaborated. A crude preparation containing both platelet-clotting factors was obtained from platelet extracts by zinc acetate precipitation, and applied to DEAE-cellulose columns. Fractions were eluted with phosphate buffer of decreasing pH and of increasing ionic strength. Complete separation of both chromatographically homogenous factors was achieved. Some characteristics of the purified factors are given. A method for determining platelet factor 2 is elaborated. It has been found that the incubation of highly purified bovine fibrinogen with platelet factor 2 is accompanied by an increase of the ability of fibrogen to be clotted by thrombin (EC 3.4.4.13) and by the parallel increase of non-protein nitrogen soluble in trichloroacetic acid. A term “fibrinogen-activating factor” was suggested to define platelet factor 2 more precisely.

Neutralization of Antithrombin VI (Fibrinogen Breakdown Products) with Platelet Antiheparin Factor (Platelet Factor 4)*

SummaryIt has been found that fibrinogen breakdown product – antithrombin VI – is neutralized by the purified preparation of platelet factor 4, obtained by means of zinc acetate precipitation and DEAE chromatography column. It has been suggested that antiheparin activity of platelet factor 4 and its ability to neutralize antithrombin VI may be related to the same protein.The purified preparation of platelet factor 4 does not influence the fibrinogen – fibrin conversion by thrombin. This means that platelet factor 2 and platelet factor 4 are not the same substance.Crude platelet extracts neutralize antithrombin III and V. However, the purified product did not interferes with the action of these antithrombins.

Histamine Sensitizing Factor of Bordetella pertussis

Histamine sensitizing factor of Bordetella perlussis was purified from the culture supernatant. Zinc acetate precipitation method was employed to concentrate HSF from the culture supernatant. By DEAE cellulose chromatography, about 30-fold purification was achieved. Dialysis of the concentrated preparation gave a precipitate fraction which showed high HSF activity of 37800 HSD50/mg. N. about 110-fold purification was thus attained. Chemical and immunological properties of the purified HSF preparation were described. It was demonstrated that HSF is an entity distinct from other cell components, such as thermolabile toxin and agglutinogen.