scholarly journals Roles of Proteins Containing Immunoglobulin-Like Domains in the Conjugation of Bacterial Plasmids

mSphere ◽  
2022 ◽  
Author(s):  
Mário Hüttener ◽  
Jon Hergueta ◽  
Manuel Bernabeu ◽  
Alejandro Prieto ◽  
Sonia Aznar ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Bacterial Cell ◽  
Cell Contact ◽  
Bacterial Plasmids ◽  
Enzymatic Machinery

Transmission of a plasmid from one bacterial cell to another, in several instances, underlies the dissemination of antimicrobial resistance (AMR) genes. The process requires well-characterized enzymatic machinery that facilitates cell-to-cell contact and the transfer of the plasmid.

scholarly journals YscP and YscU Regulate Substrate Specificity of the Yersinia Type III Secretion System

2003 ◽  
Vol 185 (7) ◽  
pp. 2259-2266 ◽  
Author(s):  
Petra J. Edqvist ◽  
Jan Olsson ◽  
Moa Lavander ◽  
Lena Sundberg ◽  
Åke Forsberg ◽  
...  
Keyword(s):  
Cell Surface ◽  
Substrate Specificity ◽  
Type Iii Secretion ◽  
Bacterial Cell ◽  
Type Iii Secretion System ◽  
Eukaryotic Cell ◽  
Secretion System ◽  
Cell Contact ◽  
Type Iii ◽  
Bacterial Cell Surface

ABSTRACT Pathogenic Yersinia species use a type III secretion system to inhibit phagocytosis by eukaryotic cells. At 37°C, the secretion system is assembled, forming a needle-like structure on the bacterial cell surface. Upon eukaryotic cell contact, six effector proteins, called Yops, are translocated into the eukaryotic cell cytosol. Here, we show that a yscP mutant exports an increased amount of the needle component YscF to the bacterial cell surface but is unable to efficiently secrete effector Yops. Mutations in the cytoplasmic domain of the inner membrane protein YscU suppress the yscP phenotype by reducing the level of YscF secretion and increasing the level of Yop secretion. These results suggest that YscP and YscU coordinately regulate the substrate specificity of the Yersinia type III secretion system. Furthermore, we show that YscP and YscU act upstream of the cell contact sensor YopN as well as the inner gatekeeper LcrG in the pathway of substrate export regulation. These results further strengthen the strong evolutionary link between flagellar biosynthesis and type III synthesis.

scholarly journals Regulation of Rhodobacter capsulatus gene transfer agent production

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Ian Duncan ◽  
David Sherlock ◽  
Paul Fogg
Keyword(s):  
Gene Transfer ◽  
Antimicrobial Resistance ◽  
Rhodobacter Capsulatus ◽  
Fluorescent Protein ◽  
Recipient Cell ◽  
Cell Contact ◽  
Structural Genes ◽  
Antimicrobial Resistance Genes ◽  
Gene Transfer Agent ◽  
A Cell

Horizontal gene transfer (HGT) enables the spread of antimicrobial resistance, virulence, metabolic and other genes conferring an advantage to the organism. HGT is enhanced in biofilms because of increased cell-cell contact (conjugation), and eDNA in the biofilm matrix causing development of competence and providing material for transformation. Production of the Rhodobacter capsulatus gene transfer agent (RcGTA), another mechanism of HGT, could also increase in biofilm as high cell density increases the proportion of GTA particles produced that encounter a target cell. RcGTA is a phage-like particle that packages ∼4.5 kb pieces of random DNA from the producing cell’s genome and transfers it to a recipient cell. Five loci comprise the RcGTA genome: a 15kb cluster containing most of the RcGTA structural genes, a cell lysis locus, two structural loci encoding head spikes and tail fibres, and a maturation/regulation locus that includes that master regulator, gafA. I assayed RcGTA production using gene transfer bioassays and biofilm using a 96 well plate assay. I will present data showing that deletion of four GTA-related genes, including gafA itself, all lead to reduced biofilm production. All four gene knock-outs also strongly reduce GTA-mediated gene transfer, suggesting GTA production and biofilm are co-regulated. I will also present work to characterize GTA production in biofilms, for example by monitoring the transfer of fluorescent protein genes through confocal microscopy, and assessing how specific regulators control this process. Biofilms are ubiquitous in the environment so studying the spread of antimicrobial resistance genes by GTAs is important.

scholarly journals Novel Biomimetic Human TLR2-Derived Peptides for Potential Targeting of Lipoteichoic Acid: An in Silico Assessment

Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1063
Author(s):  
Nikita Devnarain ◽  
Ayman Y. Waddad ◽  
Beatriz G. de la Torre ◽  
Fernando Albericio ◽  
Thirumala Govender
Keyword(s):  
Antimicrobial Resistance ◽  
Bacterial Cell ◽  
In Silico ◽  
Lipoteichoic Acid ◽  
Binding Potential ◽  
Cell Penetration ◽  
Resistance Development ◽  
Toll Like Receptor 2 ◽  
Superior Approach ◽  
Antibiotic Delivery

Antimicrobial resistance is one of the most significant threats to health and economy around the globe and has been compounded by the emergence of COVID-19, raising important consequences for antimicrobial resistance development. Contrary to conventional targeting approaches, the use of biomimetic application via nanoparticles for enhanced cellular targeting, cell penetration and localized antibiotic delivery has been highlighted as a superior approach to identify novel targeting ligands for combatting antimicrobial resistance. Gram-positive bacterial cell walls contain lipoteichoic acid (LTA), which binds specifically to Toll-like receptor 2 (TLR2) on human macrophages. This phenomenon has the potential to be exploited for the design of biomimetic peptides for antibacterial application. In this study, we have derived peptides from sequences present in human TLR2 that bind to LTA with high affinity. In silico approaches including molecular modelling, molecular docking, molecular dynamics, and thermodynamics have enabled the identification of these crucial binding amino acids, the design of four novel biomimetic TLR2-derived peptides and their LTA binding potential. The outcomes of this study have revealed that one of these novel peptides binds to LTA more strongly and stably than the other three peptides and has the potential to enhance LTA targeting and bacterial cell penetration.

scholarly journals Roles of proteins containing immunoglobulin-like domains in the conjugation of bacterial plasmids.

2021 ◽  
Author(s):  
Mario Huttener ◽  
Jon Hergueta ◽  
Manuel Bernabeu ◽  
Alejandro Prieto ◽  
Sonia Aznar ◽  
...  
Keyword(s):  
External Medium ◽  
Recipient Cell ◽  
Cell Contact ◽  
Natural Environments ◽  
Bacterial Cells ◽  
Bacterial Plasmids ◽  
Genes Encoding ◽  
High Molecular Weight Proteins ◽  
Environmental Temperatures

Horizontal transfer of bacterial plasmids generates genetic variability and contributes to the dissemination of the genes that enable bacterial cells to develop antimicrobial resistance (AMR). Several aspects of the conjugative process have long been known, namely, those related to the proteins that participate in the establishment of cell-to-cell contact and to the enzymatic processes associated with the processing of plasmid DNA and its transfer to the recipient cell. In this work, we describe the role of newly identified proteins that influence the conjugation of several plasmids. Genes encoding high-molecular-weight proteins that contain one or several immunoglobulin-like domains (Big) are located in the transfer regions of several plasmids that usually harbor AMR determinants. These Big proteins are exported to the external medium and target two extracellular organelles: the flagella and the conjugative pili. The plasmid-encoded Big proteins facilitate conjugation by reducing cell motility (by binding to flagella) and facilitating cell-to-cell contact (by binding to the conjugative pilus). They use the same export machinery as that used by the conjugative pilus components. In the examples characterized in this paper, these proteins influence conjugation at environmental temperatures (i.e., 25C). This suggests that they may play relevant roles in the dissemination of plasmids in natural environments. As they are located in outer surface organelles, they could be targeted to control the dissemination of different bacterial plasmids carrying AMR determinants.

3-D organization of fibrinogen receptors using computer reconstruction and whole-mount microscopy

1988 ◽  
Vol 46 ◽  
pp. 30-31
Author(s):  
E. T. O'Toole ◽  
R. R. Hantgan ◽  
J. C. Lewis
Keyword(s):  
Whole Blood ◽  
Colloidal Gold ◽  
Blood Platelets ◽  
Cell Contact ◽  
Computer Assisted ◽  
Adherent Cells ◽  
Differential Centrifugation ◽  
Computer Reconstruction ◽  
Sds Page ◽  
Whole Mount

Thrombocytes (TC), the avian equivalent of blood platelets, support hemostasis by aggregating at sites of injury. Studies in our lab suggested that fibrinogen (fib) is a requisite cofactor for TC aggregation but operates by an undefined mechanism. To study the interaction of fib with TC and to identify fib receptors on cells, fib was purified from pigeon plasma, conjugated to colloidal gold and used both to facilitate aggregation and as a receptor probe. Described is the application of computer assisted reconstruction and stereo whole mount microscopy to visualize the 3-D organization of fib receptors at sites of cell contact in TC aggregates and on adherent cells.Pigeon TC were obtained from citrated whole blood by differential centrifugation, washed with Ca++ free Hank's balanced salts containing 0.3% EDTA (pH 6.5) and resuspended in Ca++ free Hank's. Pigeon fib was isolated by precipitation with PEG-1000 and the purity assessed by SDS-PAGE. Fib was conjugated to 25nm colloidal gold by vortexing and the conjugates used as the ligand to identify fib receptors.

Bacterial epidemiology and antimicrobial resistance in ascitic fluid: A 2-year retrospective study

2009 ◽  
pp. 1-5 ◽  
Author(s):  
Lionel Piroth ◽  
Andre Pechinot ◽  
Anne Minello ◽  
Benoit Jaulhac ◽  
Isabelle Patry ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Antimicrobial Resistance ◽  
Ascitic Fluid
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