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Exopolysaccharide Production from Marine Bacteria and Its Applications
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Prashakha J. Shukla, Shivang B. Vhora, Ankita G. Murnal, Unnati B. Yagnik, Maheshwari Patadiya
Several studies have concluded that EPSs mediated biofilm formation is closely associated with quorum-sensing (QS) systems for the production of autoinducers (Di Donato et al., 2016). These QS mechanisms have been very well studied in the marine strain of Vibrio fischeri with two QS systems, ain and lux (Lupp and Ruby, 2005).
Cell-Cell Communication in Lactic Acid Bacteria
Published in Marcela Albuquerque Cavalcanti de Albuquerque, Alejandra de Moreno de LeBlanc, Jean Guy LeBlanc, Raquel Bedani, Lactic Acid Bacteria, 2020
Emília Maria França Lima, Beatriz Ximena Valencia Quecán, Luciana Rodrigues da Cunha, Bernadette Dora Gombossy de Melo Franco, Uelinton Manoel Pinto
Bacteria can communicate and regulate the expression of several genes according to cell density. This mechanism is a type of communication known as quorum sensing (QS), which is based on the production, secretion, and detection of small signaling molecules, whose concentration correlates with the cell density of microorganisms secreting these molecules in the surroundings (Choudhary and Schmidt-Dannert 2010). All quorum sensing systems usually involve the synthesis of a biomolecule with low molecular weight, also termed autoinducer (AI), which is recognized by the responder cell (Declerck et al. 2007, LaSarre and Federle 2013). As bacterial population density increases, the concentration of autoinducer molecules in the environment also rises (Johansen and Jespersen 2017).
Cystic fibrosis infection and biofilm busters
Published in Anthony J. Hickey, Heidi M. Mansour, Inhalation Aerosols, 2019
Jennifer Fiegel, Sachin Gharse
Bacterial cells communicate and coordinate their behavior in response to stimuli by producing, secreting, and detecting signal molecules called autoinducers. This communication process, called quorum sensing (QS), allows bacteria to alter their gene expression with the accumulation of a minimal threshold concentration of autoinducers, resulting in behavioral changes (104). QS is closely linked to biofilm formation, playing a role in production of EPS matrix, virulence factors, and bacterial dispersion from biofilms. QSIs hinder biofilm formation by inhibiting the release of EPS and prevent the production of bacterial virulence factors (105,106). Several studies have quantified the effects of QSIs on P. aeruginosa biofilms.
Exacerbation of antimicrobial resistance: another casualty of the COVID-19 pandemic?
Published in Expert Review of Anti-infective Therapy, 2021
As mentioned, quorum sensing regulates bacterial virulence in a density-depended manner, partly mediated by the signaling molecules (autoinducers); the pathogenicity of the bacteria can be reduced by manipulating the bacterial signaling circuit (Table 1). Adopting quorum quenching to reduce bacterial virulence has emerged as a viable alternative to manipulate bacterial pathogenicity and subsequent harmful effects on human and animal health. Even before the COVID-19 pandemic, numerous antimicrobial drugs have lost their efficacy, and therefore, no longer useable to treat life-threatening infections. Consequently, in the COVID-19 pandemic era, it is essential to generate novel antimicrobial compounds through innovative approaches, such as quorum quenching, to avoid rapidly developing antimicrobial resistance to prevent and treat conventional and emerging infectious diseases. Finally, establishing collaboration among different national and international agencies (government and private) is vital to attain substantial progress in delivering primary healthcare to reduce or delay antimicrobial resistance during the COVID-19 pandemic [33,34].
Quorum quenching enzymes and their effects on virulence, biofilm, and microbiomes: a review of recent advances
Published in Expert Review of Anti-infective Therapy, 2020
Bacterial QS systems rely on AIs as specialized signaling molecules. Three main classes of AIs are shown in Figure 1 – N-acyl Homoserine Lactones (AHLs) or Autoinducer-1, Autoinducing Peptides (AIPs), and Autoinducer-2 (AI-2) [7]. While the structural diversity of known signaling molecules is already large, it is very likely that more, new signaling molecules involved in QS or similar signaling systems are yet to be discovered. Known AI molecules can passively or actively diffuse across the cell membrane, bind to their cognate receptors with high specificity and trigger a cascade of signaling pathways eventually resulting in transcriptional regulation of target genes. While it is not the focus of this review, we note that signaling using the above-mentioned molecules is not limited to bacteria, but extend to eukaryotes including plants and animals [13–20].
Quorum quenching activity of pentacyclic triterpenoids leads to inhibition of biofilm formation by Acinetobacter baumannii
Published in Biofouling, 2020
Sudipta Paul Bhattacharya, Akash Mitra, Arijit Bhattacharya, Aparna Sen
Quorum sensing (QS) is a mode of communication among the members of a bacterial community, typically consisting of bacterial populations, signal molecules and dedicated gene sets. QS regulates group communication and behavior synchronization, thereby allowing bacterial populations to develop faster, gain access to more resources and secure a better chance of survival (Abisado et al. 2018). The signal molecules (or the autoinducers) are secreted into the proximal environment of bacteria and as the population grows a threshold density (1010−1011 CFU ml−1, which can vary depending on bacterial species and strains) is attained to trigger corresponding response genes that regulate attributes like virulence factor production and biofilm development (Li and Tian 2012). Biofilms allow bacteria to create a microenvironment that enables the colonizers to attach to the host surface and evade host immune responses and even exclude antibiotics (Hall-Stoodley and Stoodley 2009). Over 80% of bacterial infections in humans involve the formation of biofilms, which is the basis of multiple chronic infections (Davies 2003).