Influence of adsorption time, rocking, and soluble proteins on the plaque assay of monodispersed poliovirus

Richards, Gary P.; Weinheimer, Debra A.

doi:10.1128/aem.49.4.744-748.1985

Cited by 9 publications

(3 citation statements)

References 38 publications

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“…The hematite NPs were treated as soluble substances and their adsorption behaviors were studied following a similar method as for soluble matter. This is probably reasonable since soluble substances are traditionally defined as those that can pass through 0.45 μm filters [38]. Hematite NPs were clearly much smaller in size than 0.45 μm, as supported by the DLS measurement.…”

Section: Adsorption Kinetics Of Different Sizes Of Nps On Caco-2 Cellssupporting

confidence: 56%

Adsorption of hematite nanoparticles onto Caco-2 cells and the cellular impairments: effect of particle size

et al. 2010

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The increasing applications of engineered nanomaterials nowadays have elevated the potential of human exposure through various routes including inhalation, skin penetration and digestion. To date there is scarce information on a quantitative description of the interactions between nanoparticles (NPs) and cell surfaces and the detrimental effects from the exposure. The purpose of this work was to study in vitro exposure of Caco-2 cells to hematite (alpha-Fe(2)O(3)) NPs and to determine the particle size effects on the adsorption behaviors. Cellular impairment was also investigated and compared. Hematite NPs were synthesized as part of this study with a discrete size distribution and uniform morphology examined by dynamic light scattering (DLS) and confirmed by transmission electron microscopy (TEM). Caco-2 cells were cultured as a model epithelium to mirror human intestinal cells and used to evaluate the impacts of the exposure to NPs by measuring transepithelial electrical resistance (TEER). Cell surface disruption, localization and translocation of NPs through the cells were analyzed with immunocytochemical staining and confocal microscopy. Results showed that hematite NPs had mean diameters of 26, 53, 76 and 98 nm and were positively charged with minor aggregation in the buffer solution. Adsorption of the four sizes of NPs on cells reached equilibrium within approximately 5 min but adsorption kinetics were found to be size-dependent. The adsorption rates expressed as mg m(-2) min(-1) were greater for large NPs (76 and 98 nm) than those for small NPs (26 and 53 nm). However, adsorption rates, expressed in units of m(-2) min(-1), were much greater for small NPs than large ones. After the adsorption equilibrium was reached, the adsorbed mass of NPs on a unit area of cells was calculated and showed no significant size dependence. Longer exposure time (>3 h) induced adverse cellular effects as indicated by the drop in TEER compared to the control cells without the exposure to NPs. NPs initially triggered a dynamic reorganization and detachment of microvilli structures on Caco-2 cell surfaces. Following this impact, the drop in TEER occurred more significantly, particularly for the exposure to 26 nm NPs, which was consistent with the observations with confocal microscopy that the junctions were more severely disrupted by 26 nm NPs than other sizes. In conclusion, this paper demonstrates the interactions at the ultrastructural level from initial surface adsorption of NPs upon cells, to the subsequent microvilli reorganization, membrane penetration and the disruption of adherens junction and provides the fundamental information on size effects on NP behavior which is often poorly addressed for in vitro cytotoxicity studies of NPs.

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Section: Adsorption Kinetics Of Different Sizes Of Nps On Caco-2 Cellssupporting

confidence: 56%

Adsorption of hematite nanoparticles onto Caco-2 cells and the cellular impairments: effect of particle size

et al. 2010

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“…Adequate organic material is already present in shellfish samples, and no further addition is needed, but it may be necessary to add organics to water or sediment eluates in the form of beef extract (BE) or skim milk. Residuals of these materials may later compromise viral assays, including plaque assay (27), antigen detection immunoassays (22), and gene probe hybridization (11).…”

mentioning

confidence: 99%

Polyethylene glycol precipitation for recovery of pathogenic viruses, including hepatitis A virus and human rotavirus, from oyster, water, and sediment samples

Lewis

Metcalf

1988

Appl Environ Microbiol

372

181

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Polyethylene glycol 6000 precipitation was found to be an effective concentration method that enhanced the chances for detecting human virus pathogens in environmental samples. Percent recoveries from eluates of fresh and estuarine waters with 8% polyethylene glycol 6000 averaged 86 for hepatitis A virus, 77 for human rotavirus Wa, 87 for simian rotavirus SAll, and 68 for poliovirus. Percent recoveries of 97, 40, 97 and 105, respectively, for the same viruses were obtained from oyster eluates by the same procedure. Percent recoveries of 97 for hepatitis A virus and 78 for human rotavirus Wa were obtained from sediment eluates containing 2 M NaNO3 with a final concentration of 15% polyethylene glycol 6000. The polyethylene glycol method was shown to be more effective than the organic flocculation method for recovery of hepatitis A virus and rotaviruses Wa and SAll, but not of poliovirus 1 in laboratory studies. In field trials, hepatitis A virus or rotavirus or both were recovered from 12 of 18 eluates by polyethylene glycol, compared with recovery from 9 of 18 eluates by organic flocculation from fresh and estuarine waters subject to pollution.

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“…The numbers of infectious viruses can also be increased by using roller bottles [52]. Secondary passage on fresh cells, use of suspended cell culture, rotating or shaking the liquid in the cell culture flasks during incubation [53], and use of suspended-cell may increase the number of viruses detected. All of these methods increase the probability of contact of the virus with receptors on the cell surface, i.e., the suspended virus must come into contact with cells.…”

Section: Impact Of Assay Methods On Virus Detectionmentioning

confidence: 99%

Assessing the Occurrence of Waterborne Viruses in Reuse Systems: Analytical Limits and Needs

Gerba

Betancourt

2019

Pathogens

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Detection of waterborne enteric viruses is an essential tool in assessing the risk of waterborne transmission. Cell culture is considered a gold standard for detection of these viruses. However, it is important to recognize the uncertainty and limitations of enteric virus detection in cell culture. Cell culture cannot support replication of all virus types and strains, and numerous factors control the efficacy of specific virus detection assays, including chemical additives, cell culture passage number, and sequential passage of a sample in cell culture. These factors can result in a 2- to 100-fold underestimation of virus infectivity. Molecular methods reduce the time for detection of viruses and are useful for detection of those that do not produce cytopathogenic effects. The usefulness of polymerase chain reaction (PCR) to access virus infectivity has been demonstrated for only a limited number of enteric viruses and is limited by an understanding of the mechanism of virus inactivation. All of these issues are important to consider when assessing waterborne infectious viruses and expected goals on virus reductions needed for recycled water. The use of safety factors to account for this may be useful to ensure that the risks in drinking water and recycled water for potable reuse are minimized.

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Influence of adsorption time, rocking, and soluble proteins on the plaque assay of monodispersed poliovirus

Cited by 9 publications

References 38 publications

Adsorption of hematite nanoparticles onto Caco-2 cells and the cellular impairments: effect of particle size

Adsorption of hematite nanoparticles onto Caco-2 cells and the cellular impairments: effect of particle size

Polyethylene glycol precipitation for recovery of pathogenic viruses, including hepatitis A virus and human rotavirus, from oyster, water, and sediment samples

Assessing the Occurrence of Waterborne Viruses in Reuse Systems: Analytical Limits and Needs

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