TABLE 5.

Significantly down-regulated genes found in microarray expression analysis of L. lactis IL1403 and L. lactis IL1403 Nis^ra

Gene(s)	Avg regulation (n-fold)	P value	(Proposed) function
Energy metabolism
yeeAb	−4.5	10−9	Maltose hydrolase
pgmB	−3.4	10−7	Beta-phosphoglucomutase
yedEFb	−3.0	10−8	β-Glucoside-specific PTS system
gidA	−1.6	10−5	Glucose inhibited division protein
Membrane biosynthesis
fabDG1G2Z1Z2b	−1.5	10−5	Fatty acid biosynthesis and substrate binding permease
Regulatory functions
ybdA	−1.5	10−4	Putative transcriptional regulator
glnR	−1.5	10−9	Glutamine synthetase repressor
rmaG	−1.5	10−7	Putative transcriptional regulator
Transport and binding proteins
yriC in operon yriDCBA	−2.2	10−5	Xanthine/uracil permeases
glnP	−2.1	10−7	Glutamine ABC transporter
xpt	−1.7	10−9	Putative xanthine phosphoribosyltransferase
potD	−1.6	10−8	Putative ABC transporter
pbuX	−1.5	10−5	Xanthine permease
dacA	−1.5	10−6	Extracellular protein Exp2 precursor
plpABCD	−1.5	10−6	Outer membrane lipoprotein precursors
Miscellaneous and unknown proteins
hemH	−1.7	10−6	Ferrochelatase
ribAH in operon ribGBAH	−2.7	10−6	Riboflavin biosynthesis protein
rpsN	−2.0	10−6	30S ribosomal protein
aroH	−1.8	10−7	Tyr-sensitive phospho-2-dehydro-deoxyheptonate aldolase
phnA	−1.6	10−5	Uncharacterized Zn-ribbon-containing protein involved in phosphonate metabolism
ynbE	−1.6	10−5	Conserved hypothetical protein

^aValues represent lower (negative) expression in the L. lactis IL1403 Nis^r strain than that in the L. lactis IL1403 strain.

^bGenes investigated or discussed.