In situ investigations of single living cells infected by viruses

High-speed atomic force microscopy coming of age

“…Paul Hansma and colleagues observed at 1 min intervals the clotting process by fibrin which was initiated by the digestion of fibrinogen with thrombin [11]. A group including one of the inventors of AFM (i.e., Gerd Binnig) also attempted to image the dynamic processes of live cells being infected by virus [27] and binding of antibody to the S-layer [28]. After the introduction of the tapping mode, DNA-involved dynamic processes were studied by Paul Hansma's group and Carlos Bustamante's group; DNA digestion by DNAase [29] , binding of RNA polymerase to DNA [30], transcription process [31], and diffusion of RNA polymerase along DNA strands [32].…”

Organization of influenza A virus envelope at neutral and low pH

“…Because of its capacity to image the surface of biological structures under physiological conditions with a subnanometre vertical resolution (Engel et al, 1997), atomic force microscopy (AFM) was originally applied to the study of virus-eukaryotic cell interactions (Haberle et al, 1992). Since then, AFM has provided structures of viruses consistent with models derived by EM and X-ray crystallography (Kuznetsov et al, 2001) and has been applied to studies of the morphology of enveloped viruses such as human immunodeficiency virus (Kuznetsov et al, 2003), Moloney murine leukemia virus (Kol et al, 2006;Kuznetsov et al, 2004) and severe acute respiratory syndrome coronavirus (Lin et al, 2005).…”

High-speed atomic force microscopy for nano-visualization of dynamic biomolecular processes

“…For example, they observed the fibrin clotting process initiated by the digestion of fibrinogen with thrombin at ~1 min intervals [19]. Some trial observations of dynamic biological processes were also performed on the viral infection of isolated cells [20] and antibody binding to an S-layer protein [21]. We can imagine that it must have been difficult at this early stage to observe these dynamic processes, as only the contact-mode was available (tapping mode was invented in 1993 [5]); In the constant-force mode, biomolecules weakly attached to a surface are easily dislodged by the scanning tip.…”