Table 3.

Genes significantly differentially expressed in S. cerevisiae in response to cocultivation with Lb. delbrueckii subsp. bulgaricus^a

Type of regulation and geneb	Description	Fold change
		In cocultures vs monoculturesc	From Abbott et al.d
Upregulated genes
CTR3e	High-affinity copper transporter of the plasma membrane, acts as a trimer	4.6	−1.8
STL1	Glycerol importer	4.3	111
FIT1e	Cell wall mannoprotein, involved in the retention of siderophore iron in the cell wall	2.9	8
EEB1	Alcohol acyltransferase involved in ethyl ester biosynthesis	2.7	−5.2
FMP23e	Mitochondrial protein of unknown function, contains Rcs1p and Aft2p binding domains	2.7	19
CIN5	Transcription factor of the YAP-1 family, mediates pleiotropic drug resistance and salt tolerance	2.5	12.1
HMX1e	Endoplasmic reticulum localized, heme-binding peroxidase involved in the degradation of heme, expression regulated by Aft1p	2.5	6
SIT1e	Transporters that specifically recognize siderophore iron chelates, transcription is induced during iron deprivation and diauxic shift	2.5	11
TIS11e	mRNA-binding protein expressed during iron starvation and involved in mRNA degradation	2.3	45
CCC2e	Plasma membrane Cu2+-transporting P-type ATPase, required for export of copper from the cytosol	2.2	7
CTR1e	High-affinity copper transporter of the plasma membrane, mediates nearly all copper uptake under low-copper conditions	2.2	2.7
Downregulated genes
SUL1	High-affinity sulfate permease	−3	−12.4
CAR2	l-Ornithine transaminase, catalyzes the second step of arginine degradation	−2.2	−5.1
ATO3	Plasma membrane protein, possible role in export of ammonia from the cell	−2	−4.7
ADH2	Glucose-repressible alcohol dehydrogenase II, catalyzes the conversion of ethanol to acetaldehyde, involved in the production of certain carboxylate esters, regulated by Adr1p	−2.5	1.0
PHM8	Lysophosphatidic acid phosphatase involved in lysophosphatidic acid hydrolysis in response to phosphate starvation	−2.4	1.0
XBP1	Transcriptional repressor that binds to promoter sequences of the cyclin genes CYS3 and SMF2	−2.5	−1.1

^aDifferential expression was identified by use of a false discovery rate of <5% (see Materials and Methods).

^bGenes responding to lactic acid stress in a previous study by Abbott et al. (51) are indicated in bold.

^cThe fold change represents the increase or decrease in expression in lactose-grown chemostat cocultures compared to that in galactose-grown chemostat monocultures.

^dThe fold change represents the increase or decrease in expression in anaerobic glucose-limited chemostat cultures grown at pH 5.0 in the presence versus absence of 900 mM lactic acid, as described by Abbott et al. (51).

^eGenes encoding proteins involved in iron and copper homeostasis (51).