Table 2.

Influence of GTE5 and GRU1 phages on production of stable foams by selected mycolata strains under laboratory conditions

Culture	Foaming scorea
	Without phage	In the presence of GTE5	In the presence of GRU1
Gordonia aichiensis (Raic22)b	6	6	6
G. terrae (Gter34)	2	0	0
G. terrae (G232)	2	0	0
G. rubropertincta (Grub38)	1	0	0
N. nova (Nnov47)	1a	1a	1a

^aFoaming scores are in accordance with the modified scale of Blackall and Marshall (4) illustrated in Petrovski et al. (33, 35). The scale is as follows: 0, as for pure water with no foam; 1, 1.0 to 3.0 cm of foam with fragile, ill-formed bubbles; 1a, flotation of clumped bacterial cells to the surface of the air-water interface; 2, intermittent, sufficiently stable films; 3, substantial foaming (i.e., bubbles about 10 cm in diameter) to 3 to 8 cm high; 4, initially 8 to 15 cm of foam (about 1-cm-diameter bubbles) with stable films formed at regular intervals; 5, stable foam 5 to 10 cm high in 2 min, after which it collapses to 3 to 5 cm high (foam is stable when aeration ceases); 6, stable foam 15 to 30 cm high with no films.

^bUsed as a negative control. GTE5 and GRU1 do not lyse this host.