Understanding viral partitioning in two‐phase aqueous nonionic micellar systems: 1. Role of attractive interactions between viruses and micelles

Abstract

The partitioning behavior of viruses in the two-phase aqueous nonionic n-decyl tetra(ethylene oxide) (C10E4) micellar system cannot be fully explained by considering solely the repulsive, steric, excluded-volume interactions that operate between the viruses and the nonionic C10E4 micelles. Specifically, an excluded-volume theory developed recently by our group is not able to quantitatively predict the observed viral partition coefficients, even though this theory is capable of providing reasonable quantitative predictions of protein partition coefficients. To shed light on the discrepancy between the theoretically predicted and the experimentally measured viral partition coefficients, a central assumption underlying the excluded-volume theory that the viruses and the C10E4 micelles interact solely through repulsive, excluded-volume interactions was challenged in this study. In particular, utilizing bacteriophage P22 as a model virus, a competitive inhibition test and a partitioning study of the capsids of bacteriophage P22 were conducted. Based on the results of these two experimental studies, it was concluded that any attractive interactions between the tailspikes of bacteriophage P22 and the C10E4 micelles are negligible. Another experimental study was carried out wherein the partition coefficients of the model viruses, bacteriophages P22 and T4, were measured at various temperatures, and compared with those previously obtained for bacteriophage phiX174. This comparison also indicated that possible attractive, electromagnetic-induced interactions between the bacteriophage particles and the C10E4 micelles cannot be invoked to rationalize the observed discrepancy between the theoretically predicted and the experimentally measured viral partition coefficients.

Tailspike Interactions with Lipopolysaccharide Effect DNA Ejection from Phage P22 Particles in Vitro

“…It was kindly provided by Dr. Wolfgang Rabsch, Robert Koch Institut Wernigerode, Germany. The following strains of Salmonella enterica enterica serovar Typhimurium (S. typhimurium), were employed: DB7155 LT2 (19), SupE, amber suppressor strain; DB7136 LT2 (19); DB7136 c2ts30 containing the temperature-sensitive P22 prophage c2ts30 (13Ϫ am/9Ϫ am), a kind gift from Cameron Haase-Pettingell, Massachusetts Institute of Technology (20).…”

“…This strain contains a P22 mutant lysogen deficient in lysis (13Ϫ am) as well as in tailspike formation (9Ϫ am) and will accumulate TSP-less heads intracellularly upon induction (20). To reconstitute tailed phages, phage heads were incubated with excess TSP for 1 h at 37°C (2), centrifuged in a CsCl gradient from 1.3 to 1.7 g⅐ml Ϫ1 for 2.5 h at 98,300 ϫ g, and dialyzed against standard buffer.…”

“…Because of the amber mutations in their genome, infectivity of the reconstituted phages has to be probed on a Salmonella strain producing an amber suppressor tRNA. Once the reconstituted phage has infected a cell, progeny with fully functional TSP is produced resulting in formation of clear plaques on the glutamine inserting amber suppressor strain S. typhimurium DB7155 (20). This provides us with a tailing assay to probe the role of TSP for infection.…”

Aqueous Two‐Phase Systems (ATPSs) for Extraction and Purification of Biomolecules and Bioparticles

“…In a second work (part 1), the authors explained the behavior of all three bacteriophages partitioned similarly in function of temperature, and that the three had very different sizes (77). The authors concluded in the same work (part 2), using bacteriophage P22 as an example, that the measured viral partition coefficient at each temperature decreased by about an order of magnitude when the volume ratio was decreased from 10 to 0.1, which clearly indicated that entrainment is an important influencing viral partitioning factor.…”

Diagnosis of iron deficiency anemia using density-based fractionation of red blood cells

“…[19][20][21][22][23][24][25] Between each phase is an interface with a molecularly sharp step in density; these steps can be used to separate subpopulations of cells by density. The phases of an AMPS can be tuned to have very small differences in density (Δρ < 0.001 g/cm 3 ), can be made biocompatible, are thermodynamically stable, and reform if shaken.…”