187
are able to cleave the phospholipids to breach the eukaryotic membrane for invasion. PapR peptide binds to PlcR which in turn, changes the conformation of PlcR
to activate it. The activated PlcR binds to PlcR box found in DNA to regulate the
transcription. A 48 amino acid long pro-autoinducing peptide is synthesized by
papR gene and exported out of the cell. Then, this peptide is returned back into the
cell through an oligopeptide transporter, OppABCDF system. The pro-peptide is
processed to form an active oligopeptide (Gominet et al. 2001; Bouillaut et al.
2008). CodY acts as a common nutrient responsive regulator in PlcR-Pap and
Spo0A-AbrB and is involved in the activation of genes in PlcR-Pap regulon (Frenzel
et al. 2012).
8.4 Autoinducer-2
The autoinducer-2 (AI-2) is commonly found in both the Gram positive and Gram
negative bacteria. Therefore, it is also called a “universal language” of communication between bacteria. The precursor of autoinducer-2 is 4,5,-dihydroxy-2,3pentanedione (DPD) produced by LuxS, which converts S-ribosylhomocysteine to
homocysteine (Vendeville et al. 2005). DPD cyclizes to activate the icaR pathway
involved in the repression of N-acetyl glucosamine (UDP-GlcNAc) polymerization
and attenuate the biofilm formation (Yu et al. 2012). In the previous study, it was
reported that Staphylococcus aureus ΔluxS form stronger biofilm in comparison to
wild type bacteria. AI-2 sensing depends on the phosphoenolpyruvate dependent
sugar phosphotransferase system (Trappetti et al. 2017). AI-2 based quorum sensing
plays an important role in the regulation of motility, virulence, biofilm formation
and luminescence (González Barrios et al. 2006; Noor et al. 2019).
8.5 Quorum Sensing Molecules Database
With time, the new mechanisms and molecules participating in quorum sensing are
invented. To store the information of quorum sensing pathways and molecules, two
databases were developed.
8.5.1 SigMol Database
SigMol (http://bioinfo.imtech.res.in/manojk/sigmol) is an exclusive repository of
prokaryotic quorum sensing signaling molecules (QSSMs) implicated in different
quorum sensing systems like AHLs (N-Acyl homoserine lactones), HAQs
(4-hydroxy-2-alkylquinolines), DKPs (Diketopiperazines), AI-2 (Autoinducer-2),
DSFs (Diffusible Signal Factors), etc. from different bacteria and archaea. In the
8 Intrusion of Bacterial Quorum-Sensing for Antimicrobial Resistance Mitigation…
are able to cleave the phospholipids to breach the eukaryotic membrane for invasion. PapR peptide binds to PlcR which in turn, changes the conformation of PlcR
to activate it. The activated PlcR binds to PlcR box found in DNA to regulate the
transcription. A 48 amino acid long pro-autoinducing peptide is synthesized by
papR gene and exported out of the cell. Then, this peptide is returned back into the
cell through an oligopeptide transporter, OppABCDF system. The pro-peptide is
processed to form an active oligopeptide (Gominet et al. 2001; Bouillaut et al.
2008). CodY acts as a common nutrient responsive regulator in PlcR-Pap and
Spo0A-AbrB and is involved in the activation of genes in PlcR-Pap regulon (Frenzel
et al. 2012).
8.4 Autoinducer-2
The autoinducer-2 (AI-2) is commonly found in both the Gram positive and Gram
negative bacteria. Therefore, it is also called a “universal language” of communication between bacteria. The precursor of autoinducer-2 is 4,5,-dihydroxy-2,3pentanedione (DPD) produced by LuxS, which converts S-ribosylhomocysteine to
homocysteine (Vendeville et al. 2005). DPD cyclizes to activate the icaR pathway
involved in the repression of N-acetyl glucosamine (UDP-GlcNAc) polymerization
and attenuate the biofilm formation (Yu et al. 2012). In the previous study, it was
reported that Staphylococcus aureus ΔluxS form stronger biofilm in comparison to
wild type bacteria. AI-2 sensing depends on the phosphoenolpyruvate dependent
sugar phosphotransferase system (Trappetti et al. 2017). AI-2 based quorum sensing
plays an important role in the regulation of motility, virulence, biofilm formation
and luminescence (González Barrios et al. 2006; Noor et al. 2019).
8.5 Quorum Sensing Molecules Database
With time, the new mechanisms and molecules participating in quorum sensing are
invented. To store the information of quorum sensing pathways and molecules, two
databases were developed.
8.5.1 SigMol Database
SigMol (http://bioinfo.imtech.res.in/manojk/sigmol) is an exclusive repository of
prokaryotic quorum sensing signaling molecules (QSSMs) implicated in different
quorum sensing systems like AHLs (N-Acyl homoserine lactones), HAQs
(4-hydroxy-2-alkylquinolines), DKPs (Diketopiperazines), AI-2 (Autoinducer-2),
DSFs (Diffusible Signal Factors), etc. from different bacteria and archaea. In the
8 Intrusion of Bacterial Quorum-Sensing for Antimicrobial Resistance Mitigation…