Table 1.

Symbiotic colonization effectiveness of auxotrophic V. fischeri strains

Strain	Auxotrophy	Inferred genotype*	Relative colonization effectiveness†, %
ESR1	None	Wild type	100
G1	Arginine	argG1	52
G2	Cysteine	cys1	5
G3	Glycine	glyA1	120
G4	Leucine	leu1	22
G5	Lysine	lysA1	4
G6	Methionine	met1	23
G7	Proline	pro1	36
G8	Serine	ser1	5
G9	Threonine	thr1	5

^*The genotype is used to indicate the possible identity of the missing enzyme activity in the biosynthetic pathway for each amino acid. These predictions are based on the identity of the most proximal metabolic intermediate that is able to complement the auxotrophic defect (25). (See Materials and Methods.) 

^†Each value is the mean of determinations made on between four and eight juvenile animals 45 h after inoculation; all values were significant to within ±8% or better. The wild-type level (100%) was 8 × 10⁵ V. fischeri cells per light organ.