Prophage Induction in Natural Populations of Heterotrophic Bacteria
For unconcentrated seawater samples, add 25 mL each to a control or treatment, 50-mL sterile, conical centrifuge tubes.
Take an additional sample (25 mL) and fix with 1% 0.02-µm filtered formalin.
For the treatment samples, add 1 µg/mL mitomycin C (or 0.5 µg/mL in oligotrophic environments).
The samples are incubated for 16–24 h at room temperature and fixed with either 2% glutaraldehyde (for TEM), 1% formalin (epifluorescence microscopy), or 1% formalin/0.5% glutaraldehyde (flow cytometry [FCM]).
Samples for enumeration by epifluorescence microscopy should be counted within 24 h of collection or stored as frozen slides stained with SYBR Gold.
Count both bacteria and viruses in control and treated samples.
Calculate the % lysogenic bacteria as follows:% lysogens = [(VDCT - VDCC)/Bz]/BDC T=o'. 
The average burst size can be derived by TEM observation of bacterial bursts (i.e., when viruses become visible in the cell at the end of the latent period; Ackermann/Heldal, this volume).
