TEM |
Tailed phages were the most abundant VLPs in human faeces (Flewett et al., 1974). |
Visualisation of phage morphology. |
Biased towards identifying tailed phages due to potential loss of tail structures in sample preparation (Williamson et al., 2008). |
Faecal samples from patients were found to share no VLPs (Hoyles et al., 2014). |
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Limited to observations of morphologies. |
Time-consuming. |
EFM |
Up to 5.58 x 109 VLPs were observed per gram of faeces (Hoyles et al., 2014). |
Enumeration of VLPs in samples. |
VLP counts are conservative estimates of true viral abundances, given the imprecision of visualising single fluorescent dots. |
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Can validate viral purification procedures. |
Loss of VLPs during preparation and filtration of samples, e.g. large VLPs of the order Megavirales (Colson et al., 2010). |
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Greater accuracy and speed compared to TEM. |
Viability of the VLP to infect and lyse bacterial cells is unknown. |
VLPs may be membrane vesicles, gene transfer agents or cell debris containing nucleic acids (Forterre et al., 2013). |
phageFISH |
The viability of VLPs can be determined through single cell dynamic measurements, as shown with marine phages (Allers et al., 2013). |
PhageFISH is the only non-genetic method to implicate lytic, lysogenic, and chronic phage infection modes (Dang and Sullivan, 2014). |
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CLSM |
The complex microenvironment and spatiotemporal succession can be studied in multispecies biofilms, as shown with non-phage viruses (Røder et al., 2016). |
Non-destructive sampling. Can be used to visualise the biofilm infection over time. |
Limited to biofilms of bacterial species which can be fluorescently labelled. |
CryoEM |
Phage capsids of Bortadella phages were visualised at angstrom resolution, discovering unique protein folds, as shown with non-gut phages (Zhang et al., 2013). |
Very high resolution. |
Destructive sampling. |