Quorum Sensing: An Under-Explored Phenomenon in the Phylum Actinobacteria

Abstract

Quorum sensing is known to play a major role in the regulation of secondary metabolite production, especially, antibiotics, and morphogenesis in the phylum Actinobacteria. Although it is one of the largest bacterial phylum, only 25 of the 342 genera have been reported to use quorum sensing. Of these, only nine have accompanying experimental evidence; the rest are only known through bioinformatic analysis of gene/genome sequences. It is evident that this important communication mechanism is not extensively explored in Actinobacteria. In this review, we summarize the different quorum sensing systems while identifying the limitations of the existing screening strategies and addressing the improvements that have taken place in this field in recent years. The γ-butyrolactone system turned out to be almost exclusively limited to this phylum. In addition, methylenomycin furans, AI-2 and other putative AHL-like signaling molecules are also reported in Actinobacteria. The lack of existing screening systems in detecting minute quantities and of a wider range of signaling molecules was a major reason behind the limited information available on quorum sensing in this phylum. However, recent improvements in screening strategies hold a promising future and are likely to increase the discovery of new signaling molecules. Further, the quorum quenching ability in many Actinobacteria has a great potential in controlling the spread of plant and animal pathogens. A systematic and coordinated effort is required to screen and exploit the enormous potential that quorum sensing in the phylum Actinobacteria has to offer for human benefit.

Prophage induction mediated by quorum sensing signals alters soil bacterial community structure

“…Quorum sensing has been demonstrated to be widespread among bacteria [28][29][30] , however AHLs have not been shown as quorum sensing signals for many of the AHL-impacted bacterial groups in the present study, such as Nocardioides, Streptomyces, Pedobacter, and Verrucomicrbium. Thus, we propose a new hypothesis that prophages in a host cell can respond to the bacterial quorum sensing signals of different taxa other than the infected host.…”

Isolation and Characterisation of Ralstonia Solanacearum Strains of Tomato Wilt Disease from Maseno, Kenya

“…All of the plant pathogenic bacteria are usually Gram negative except Clavibacter and Streptomyces [32] ; [33]. All four tomato strains of R. solanacearum (Maseno, Mariwa, Seme and Holo) from Maseno region were…”

Baicalin Inhibits Biofilm Formation and the Quorum-Sensing System by Regulating the MsrA Drug Efflux Pump in Staphylococcus saprophyticus

“…Presumably, baicalin may be a potential agent for treating biofilm infections by either inhibiting biofilm formation or eradicating biofilms in combination with Azm. In addition, multidrug efflux pumps often secrete metabolites involved in QS (Polkade et al, 2016). QS is a process of bacterial cell-cell communication that allows bacteria to sense cell density and change bacterial gene expression patterns to alter bacteria group behaviors at high cell numbers (Rutherford and Bassler, 2012;Camilli and Bassler, 2006).…”