TABLE 1.

Leptolyngbya strains used in this study

Strain designation	Isolation date	Isolation site
VRUC184 CSC7-1/Albertano et Bruno	1994	Catacombs of St. Callistus, on tufa
VRUC201 CD2/Kovacik et Albertano	1992	Catacombs of Domitilla, on plaster
VRUC206 CSC8/Kovacik et Albertano	1992	Catacombs of St. Callistus, on tufa
VRUC192 CP9-1/Albertano	1992	Catacombs of Priscilla, on tufa
VRUC198 CSS6-3/Albertano	1992	Catacombs of St. Sebastian, on tufa
VRUC135/Albertano	1985	Domus Aurea, on frescoes