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Phytomedicines Targeting Antibiotic Resistance through Quorum Sensing and Biofilm Formation Associated with Acne Vulgaris
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
Isa A. Lambrechts, Namrita Lall
Gram-positive bacteria use a two-component communication system. First, an adenosine triphosphate (ATP)-binding cassette known as ABC exporter protein transports processed AL molecules from the bacteria to the extracellular matrix. Once the peptide-signaling molecules reach a threshold concentration, the secreted peptide signals bind to a histidine kinase sensor protein on the bacterial membrane. Bassler (1999, pp. 582–587) reports that “autophosphorylation occurs on a conserved histidine residue, transferring the phosphoryl group to a cognate response regulator on a conserved aspartate residue.” Following that, the phosphorylated response regulator binds to the lux promoters, suppressing or activating gene transcription (Figure 3.2) (Bassler, 1999).
Quorum Sensing and Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Isabel Charlotte Soede, Gerhard Buchbauer
Gram-positive bacteria use autoinducing peptides (AIPs) as signals. AIPs cannot freely diffuse through the membrane; they bind on extracellular histidine kinase receptors. This signaling way is classified as a “two-component” type, as it consists of a sensor and a response-regulator protein. As soon as the molecule binds, the kinase activity of the receptor is activated, which leads to a phosphorylation cascade resulting in the binding of a responsive regulator, a DNA-binding regulator controlling the transcription of QS genes. Bacteria using this kind of signaling path are Bacillus subtilis, Streptococcus pneumonaiae, and Staphylococcus aureus. For the excretion of AIPs, bacteria often express ATP-binding cassette (ABC)-transporter (Kleerebezem et al., 1997).
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
Nisin is a polypeptide member of the antibiotic family called lantibiotics. Thus, it possesses the amino-acid lanthionine in its composition, as the other bacteriocins of this group, besides having methyl-lanthionine, dehydroalanine (Dha) and dehydrobutyrine (Dhb) residues (Dunny and Leonard 1997, Kleerebezem and Quadri 2001, Williams and Delves-Broughton 2003, Jung et al. 2018). The precursor for nisin consists of two parts: a leader peptide, and a modifiable core peptide. The leader peptide contributes to the interaction between nisin and dedicated enzymes (NisB and NisC), to perform post-translational modification in the molecule. NisB dehydrates serines and threonines, while NisC covalently couples thiol groups of Cys to Dha or Dhb. These modified enzymes form a complex with the ABC transport protein (NisT) which is likely involved in the secretion of the modified pre-nisin molecule. Thus, NisB, NisC and NisT consist in a complex of nisin modification enzymes (Kleerebezem and Quadri 2001, Khusainov et al. 2013). The autoregulation process in Lactococcus lactis is mediated by two component regulatory system: the histidine kinase NisK that acts as a sensor for nisin, and the response regulator NisR (Table 2). Once the signal is transduced by autophosphorylation of NisK and subsequent phospho-transfer to NisR, the transcription of target genes is activated (Kuipers et al. 1998, Hilmi et al. 2006, Jung et al. 2018). A similar mechanism is depicted in Figure 1.
Quorum sensing: a new prospect for the management of antimicrobial-resistant infectious diseases
Published in Expert Review of Anti-infective Therapy, 2021
Mainul Haque, Salequl Islam, Md Arif Sheikh, Sameer Dhingra, Peace Uwambaye, Francesco Maria Labricciosa, Katia Iskandar, Jaykaran Charan, Alaeddin Bashir Abukabda, Dilshad Jahan
c. A sufficiently high concentration of QS signaling molecules is required to activate the expression of genes essential for cooperative activities within a microbial community [3,70]. This feed-forward signaling loop probably initiates and maintains synchrony among the members of the microbial population [3]. GN and GP microbial populations have unique QS systems [1,3,15,16]. The GP bacterial community produces small diffusible hormone-like peptides as signaling molecules [3,63,71]. At high microbial densities, these diffusible signaling molecule concentrations reach a critical level [3]. These signaling molecules then bind, interact with, and activate two-component histidine kinase receptors, that auto-phosphorylate and pass a phosphate molecule to a related cytoplasmic response regulator [3,66,72]. Finally, the regulator molecule activates the transcription of genes in the QS regulon [3,66,72]. The GP bacterial community produces small, freely diffusible signaling molecules, called autoinducing peptides (AIPs) as well as signaling molecules named autoinducer-2 (AI-2) [3,8]. These signaling molecules interact with membrane-bound receptors to activate transcription factors responsible for the regulation of the expression of specific genes. GN bacteria also possess two-component histidine kinase receptors [3,8]. Four characteristics common to virtually all known GN QS have been reported has been reported that four common characteristics are observed in virtually all known GN QS [69]:
Rhizobacterial biofilm and plant growth promoting trait enhancement by organic acids and sugars
Published in Biofouling, 2020
Jishma Panichikkal, Radhakrishnan Edayileveetil Krishnankutty
Bacterial chemotaxis is considered to be activated by the binding of a stimulating molecule to a cognate chemoreceptor which is composed of a methyl-accepting (MA) domain, a cytosolic signaling domain, a HAMP (histidine kinase, adenyl cyclase, methyl-accepting chemotaxis protein (MCP) and phosphatase) linker and a ligand-binding domain (LBD) (Hida et al. 2020). In the case of rhizobacteria, the signaling has also been reported to be induced by components in root exudates such as organic acids and sugars (Feng et al. 2018). Cell-to-cell communication mechanisms such as quorum sensing (QS) may also occur in accordance with bacterial population density (Helman and Chernin 2015). There are emerging reports on the role of QS signal molecules in rhizobacterial biofilm formation and the colonization of rhizobacteria on plants (Schikora et al. 2016). Living within a biofilm provides protection to rhizobacteria from predation, desiccation and antimicrobial substances. Also, it favors enhanced rhizobacterial nutrient acquisition. In return for these advantages, rhizobacteria augment the plant growth, health and tolerance to diverse stress conditions (Podile et al. 2014). Hence, the current study is focused on understanding rhizobacterial biofilm formation in response to the addition of selected organic acids and sugars.
Mechanisms of antimicrobial resistance in Stenotrophomonas maltophilia: a review of current knowledge
Published in Expert Review of Anti-infective Therapy, 2020
Teresa Gil-Gil, José Luis Martínez, Paula Blanco
Recent assays based in experimental evolution studies have shed light in the mutational trajectories leading to antibiotic resistance of antibiotics currently in use for treating infections caused by S. maltophilia. A recently-published work has revealed that the first steps to acquire ceftazidime resistance are amino acid substitutions in the gene encoding the efflux pump transporter SmeH [58]. Conversely to the tigecycline experimental evolution study that is described below, in this work the acquisition of resistance is not due to the efflux pump overexpression, but to changes in both the access and deep binding pockets of the protein (Figure 1), which supposedly ameliorates the entrance and recognition of the substrates, mainly of beta-lactams [58]. Amino acid substitutions were also found in other genes during the evolution period, as in the two-component sensor histidine kinase PhoQ, or the penicillin binding protein FtsI. Whether these mutations are directly involved in resistance or they are compensatory mutations, is a question that needs further research [58]. Overexpression of smeH, coding the efflux protein of SmeGH has been also linked to reduced susceptibility toward fluoroquinolones, although the molecular mechanisms behind this overexpression have not been elucidated yet [87].