title: Dynamic Measurements of the Position, Orientation, and DNA Content of Individual Unlabeled Bacteriophages.
abstract: A complete understanding of the cellular pathways involved in viral infections will ultimately require a diverse arsenal of experimental techniques, including methods for tracking individual viruses and their interactions with the host. Here we demonstrate the use of holographic microscopy to track the position, orientation, and DNA content of unlabeled bacteriophages (phages) in solution near a planar, functionalized glass surface. We simultaneously track over 100 individual λ phages at a rate of 100 Hz across a 33 μm × 33 μm portion of the surface. The technique determines the in-plane motion of the phage to nanometer precision, and the height of the phage above the surface to 100 nm precision. Additionally, we track the DNA content of individual phages as they eject their genome following the addition of detergent-solubilized LamB receptor. The technique determines the fraction of DNA remaining in the phage to within 10% of the total 48.5 kilobase pairs. Analysis of the data reveals that under certain conditions, λ phages move along the surface with their heads down and intermittently stick to the surface by their tails, causing them to stand up. Furthermore, we find that in buffer containing high concentrations of both monovalent and divalent salts, λ phages eject their entire DNA in about 7 s. Taken together, these measurements highlight the potential of holographic microscopy to resolve the fast kinetics of the early stages of phage infection.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Goldfain
authors.forename: Rees F
authors.initials: RF
authors.lastname: Garmann
authors.affiliation: Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.
authors.forename: Yan
authors.initials: Y
authors.lastname: Jin
authors.forename: Yoav
authors.initials: Y
authors.lastname: Lahini
authors.forename: Vinothan N
authors.initials: VN
authors.lastname: Manoharan
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D010582:Bacteriophage lambda / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D002021:Buffers; D004279:DNA, Viral / Q000737:chemistry; D003902:Detergents / Q000737:chemistry; D004058:Diffusion; D004926:Escherichia coli; D005898:Glass; D006696:Holography / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008853:Microscopy / Q000379:methods*; D009038:Motion; D012492:Salts / Q000737:chemistry; D012996:Solutions
chemical_list: D001426:Bacterial Proteins; D002021:Buffers; D004279:DNA, Viral; D003902:Detergents; D012492:Salts; D012996:Solutions