Review
Copyright ©The Author(s) 2016.
World J Gastroenterol. Sep 7, 2016; 22(33): 7402-7414
Published online Sep 7, 2016. doi: 10.3748/wjg.v22.i33.7402
Table 2 Phenotypes associated with enzymes of poly P and ppGpp metabolism
PhenotypePPK1PPK2PPX1PPX2PPX1-PPX2PhoAcjSpoT
Poly P metabolism
Poly P synthesis/accumulation↑----↑↑
Poly P-dependent GTP synthesis-↑NTNTNTNTNT
Poly P degradation--↑↑↑NTNT
Maintenance of ATP:GTP ratioNT↑NTNTNTNTNT
ppGpp metabolism
ppGpp synthesisNT-↑-↑NT↑
Stress survival
Stationary phase survival and growth------↑
Survival under low CO2NTNTNTNTNTNT↑
Osmotic shock survival↑↑↑↑↑↑NT
Low nutrient stress survival↑↑↑↑↑↑NT
Aerobic stress survival-↑NTNTNTNT↑
VBNC formation↑↑NTNTNTNTNT
Natural transformation↑NTNTNTNTNTNT
Antimicrobial resistance↑↑NTNTNT↓R
Virulence-related
Motility--↑↑↑NTNT
Biofilm formation↓↓↑↑↑↓NT
Resistance to complement-mediated killingNTNT↑↑↑NTNT
AdherenceNT-NTNTNTNT↑
Invasion-↑↑↑↑↑↑
Intraepithelial survival↑↑↑↑↑↑↑
Chicken colonization↑↑NTNTNT↑NT
NT: Not tested; R: Tested only for Rifampicin resistance; -: Phenotype absent; ↑: Phenotype is positively regulated i.e., deletion of the gene reduces the phenotype when compared to wildtype; ↓: Phenotype is negatively regulated i.e., deletion of the gene enhances the phenotype when compared to wildtype.