TABLE 2.

Arginine and pyrimidine nutritional requirements in normal and CO₂-enriched air

Phenotype	Group	No. of strains				Concn of CO2 in air (%)	Growth in DLA supplemented witha:
		L. plantarum (n = 150)	L. pentosus (n = 32)	L. paraplantarum (n = 15)	L. casei (n = 10)		Nothing	Ura + Arg or Ura + Cit	Arg or Cit	Ura	Orn
Prototrophs		94	16	3	0	<0.01	+	++	++	−	+
						4	++	++	++	++	++
Auxotrophs for uracil		0	1	0	0	<0.01	−	++	−	−	−
						4	−	++	−	++	−
Auxotrophs for Arginine	Ornithine auxotrophs	6	0	0	0	<0.01	−	+	—b	−	−
						4	−	++	++	−	+
	Citrulline auxotrophs	1	2	0	10	<0.01	−	+	—c	−	−
						4	−	++	++	−	−
HCR auxotrophs for arginine and uracil	Class 1	33	12	8	0	<0.01	−	++	−	−	−
						4	++	++	++	++	++
	Class 2	10	1	0	0	<0.01	−	++	+d	−	−
						4	++	++	++	−	++
	Class 3	6	0	4	0	<0.01	−	++	+	−	−
						4	++	++	++	++	++

^aGrowth was tested on defined DLA agar plates supplemented with combinations of uracil, arginine, citrulline, and ornithine (Ura, Arg, Cit, and Orn, respectively). −, no growth; +, good growth; ++, very good growth. c, No growth for CST 10927.

^bNCFB 963, NCFB 965, NCFB 2171, and FB400 grew, but KOG5 and NCFB 772 did not grow.

^cCST 10927 did not grow. CCM 3626 grew after 3 days. Other strains were bradytrophs (they grew very slowly in the absence of arginine or citrulline), so three additional days of incubation was necessary to detect growth.

^dNCIMB 8826, ALAB20, IN5, CNRZ 1573, CNRZ 1395, and JCL1279 did not grow in the presence of arginine in ordinary air.