358
14.4.1.4 Synthetic Quorum Sensing Inhibitors
There are three ways to block QS using synthetic quorum sensing Inhibitors:
1. Substitution of acyl side chain without any change in the lactone ring inhibits
quorum sensing in an effective manner.
2. Substitutions and alterations in the lactone ring with unchanged acyl side chain.
3. Extensive modifications in both the acyl side chain and the lactone ring.
Several quorum sensing inhibitor compounds with structures unrelated to the
signal molecules, including 4-nitro-pyridine-N-oxide (4-NPO), indole,
p- benzoquinone, 2,4,5-tribromoimidazole, indole, and 3-nitrobenzene sulphone
amide, have also been found to exert similar quorum sensing inhibitory effects
(Adak et al. 2011).
14.5 Applications of Quorum Quenching
Most of the applications have been already discussed and some specific applications
are discussed in the following sections
(a) Quorum Quenching in periodontal bacteria
Oral bacteria like Porphyromonas gingivalis, Actinobacillus, Actinomycetum
commitans, Streptococcus species, etc. communicate and coordinate their pathogenic behavior via quorum sensing (Yada et al. 2015). Thus, disruption of quorum
sensing in such pathogens will be effective in controlling periodontal diseases
(Defoirdt et al. 2013).
(b) Quorum Sensing Inhibitors for animal breeding
It has been found that at least half of the dairy cattle are affected by uterine infection causing infertility by disrupting uterine and ovarian function. Trueperella pyrogenes, Escherichia coli, Bacillus sp., and Streptococcus uberis are mostly involved
in this disease. Most of these bacteria are biofilm forming and for the formation of
biofilms they use QS. Bacterial behavior within biofilms is regulated by the phenomenon of QS (Bhargava et al. 2010; Romero et al. 2012). Disrupting the bacterial
Quorum Sensing process using various Quorum Quenching agents will hamper the
biofilm formation which may pave the way to combat many diseases.
(c) Control of membrane biofouling
Membrane biofouling is a most frequent and an adverse event in wastewater
treatment resulting in significant loss of treatment efficiency as well as the economy. Inactivation of AHL molecules has been proved to be a promising approach to
check membrane biofouling (Xu et al. 2003; Lade et al. 2014). Two quorum
G. Seghal Kiran et al.
14.4.1.4 Synthetic Quorum Sensing Inhibitors
There are three ways to block QS using synthetic quorum sensing Inhibitors:
1. Substitution of acyl side chain without any change in the lactone ring inhibits
quorum sensing in an effective manner.
2. Substitutions and alterations in the lactone ring with unchanged acyl side chain.
3. Extensive modifications in both the acyl side chain and the lactone ring.
Several quorum sensing inhibitor compounds with structures unrelated to the
signal molecules, including 4-nitro-pyridine-N-oxide (4-NPO), indole,
p- benzoquinone, 2,4,5-tribromoimidazole, indole, and 3-nitrobenzene sulphone
amide, have also been found to exert similar quorum sensing inhibitory effects
(Adak et al. 2011).
14.5 Applications of Quorum Quenching
Most of the applications have been already discussed and some specific applications
are discussed in the following sections
(a) Quorum Quenching in periodontal bacteria
Oral bacteria like Porphyromonas gingivalis, Actinobacillus, Actinomycetum
commitans, Streptococcus species, etc. communicate and coordinate their pathogenic behavior via quorum sensing (Yada et al. 2015). Thus, disruption of quorum
sensing in such pathogens will be effective in controlling periodontal diseases
(Defoirdt et al. 2013).
(b) Quorum Sensing Inhibitors for animal breeding
It has been found that at least half of the dairy cattle are affected by uterine infection causing infertility by disrupting uterine and ovarian function. Trueperella pyrogenes, Escherichia coli, Bacillus sp., and Streptococcus uberis are mostly involved
in this disease. Most of these bacteria are biofilm forming and for the formation of
biofilms they use QS. Bacterial behavior within biofilms is regulated by the phenomenon of QS (Bhargava et al. 2010; Romero et al. 2012). Disrupting the bacterial
Quorum Sensing process using various Quorum Quenching agents will hamper the
biofilm formation which may pave the way to combat many diseases.
(c) Control of membrane biofouling
Membrane biofouling is a most frequent and an adverse event in wastewater
treatment resulting in significant loss of treatment efficiency as well as the economy. Inactivation of AHL molecules has been proved to be a promising approach to
check membrane biofouling (Xu et al. 2003; Lade et al. 2014). Two quorum
G. Seghal Kiran et al.