scholarly journals The importance of the bacterial cell wall in uranium(vi) biosorption

2021 ◽  
Author(s):  
Joseph Hufton ◽  
John Harding ◽  
Thomas Smith ◽  
Maria E. Romero-González
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Cell Envelope ◽  
Bacterial Cell Wall ◽  
Controlling Factor ◽  
Bacterial Cell Envelope

The bacterial cell envelope, in particular the cell wall, is considered the main controlling factor in the biosorption of aqueous uranium(vi) by microorganisms.

scholarly journals CsiA is a bacterial cell wall synthesis inhibitor contributing to DNA translocation through the cell envelope

2009 ◽  
Vol 72 (3) ◽  
pp. 779-794 ◽  
Author(s):  
Régis Stentz ◽  
Udo Wegmann ◽  
Mary Parker ◽  
Roy Bongaerts ◽  
Laurie Lesaint ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Cell Envelope ◽  
Bacterial Cell Wall ◽  
Cell Wall Synthesis ◽  
Dna Translocation ◽  
Synthesis Inhibitor ◽  
Cell Wall Synthesis Inhibitor

scholarly journals A Secreted NlpC/P60 Endopeptidase from Photobacterium damselae subsp. piscicida Cleaves the Peptidoglycan of Potentially Competing Bacteria

mSphere ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Johnny Lisboa ◽  
Cassilda Pereira ◽  
Aline Rifflet ◽  
Juan Ayala ◽  
Mateus S. Terceti ◽  
...  
Keyword(s):  
Cell Wall ◽  
Marine Fish ◽  
High Mortality ◽  
Bacterial Cell ◽  
Structural Integrity ◽  
Cell Envelope ◽  
Bacterial Cell Wall ◽  
Gram Negative ◽  
Content Type ◽  
Photobacterium Damselae

ABSTRACT Peptidoglycan (PG) is a major component of the bacterial cell wall, forming a mesh-like structure enwrapping the bacteria that is essential for maintaining structural integrity and providing support for anchoring other components of the cell envelope. PG biogenesis is highly dynamic and requires multiple enzymes, including several hydrolases that cleave glycosidic or amide bonds in the PG. This work describes the structural and functional characterization of an NlpC/P60-containing peptidase from Photobacterium damselae subsp. piscicida (Phdp), a Gram-negative bacterium that causes high mortality of warm-water marine fish with great impact for the aquaculture industry. PnpA (Photobacterium NlpC-like protein A) has a four-domain structure with a hydrophobic and narrow access to the catalytic center and specificity for the γ-d-glutamyl-meso-diaminopimelic acid bond. However, PnpA does not cleave the PG of Phdp or PG of several Gram-negative and Gram-positive bacterial species. Interestingly, it is secreted by the Phdp type II secretion system and degrades the PG of Vibrio anguillarum and Vibrio vulnificus. This suggests that PnpA is used by Phdp to gain an advantage over bacteria that compete for the same resources or to obtain nutrients in nutrient-scarce environments. Comparison of the muropeptide composition of PG susceptible and resistant to the catalytic activity of PnpA showed that the global content of muropeptides is similar, suggesting that susceptibility to PnpA is determined by the three-dimensional organization of the muropeptides in the PG. IMPORTANCE Peptidoglycan (PG) is a major component of the bacterial cell wall formed by long chains of two alternating sugars interconnected by short peptides, generating a mesh-like structure that enwraps the bacterial cell. Although PG provides structural integrity and support for anchoring other components of the cell envelope, it is constantly being remodeled through the action of specific enzymes that cleave or join its components. Here, it is shown that Photobacterium damselae subsp. piscicida, a bacterium that causes high mortality in warm-water marine fish, produces PnpA, an enzyme that is secreted into the environment and is able to cleave the PG of potentially competing bacteria, either to gain a competitive advantage and/or to obtain nutrients. The specificity of PnpA for the PG of some bacteria and its inability to cleave others may be explained by differences in the structure of the PG mesh and not by different muropeptide composition.

scholarly journals Interactions of surfactants with the bacterial cell wall and inner membrane: Revealing the link between aggregation and antimicrobial activity

2021 ◽  
Author(s):  
Pradyumn Sharma ◽  
Rakesh K. Vaiwala ◽  
Srividhya Parthasarathi ◽  
Nivedita Patil ◽  
Morris Waskar ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Cell Wall ◽  
Molecular Dynamics Simulations ◽  
Bacterial Cell ◽  
Cell Envelope ◽  
Bacterial Cell Wall ◽  
Inner Membrane ◽  
Bending Modulus ◽  
Dynamics Simulations ◽  
Peptidoglycan Layer

Surfactants with their intrinsic ability to solubilize lipids are widely used as antibacterial agents. Interaction of surfactants with the bacterial cell envelope is complicated due to their propensity to aggregate. It is important to discern the interactions of micellar aggregates and single surfactants on the various components of the cell envelope to improve selectivity and augment the efficacy of surfactant-based products. In this study, we present a combined experimental and molecular dynamics investigation to unravel the molecular basis for the superior kill efficacy of laurate over oleate observed in contact time assays with live E. coli. To gain a molecular understanding of these differences, we performed all-atom molecular dynamics simulations to observe the interactions of surfactants with the periplasmic peptidoglycan layer and the inner membrane of Gram-negative bacteria. The peptidoglycan layer allows a greater number of translocation events for laurate when compared with oleate molecules. More interestingly, aggregates did not translocate the peptidoglycan layer, thereby revealing an intrinsic sieving property of the bacterial cell wall to effectively modulate the surfactant concentration at the inner membrane. The molecular dynamics simulations exhibit greater thinning of the inner membrane in the presence of laurate when compared with oleate, and laurate induced greater disorder and decreased the bending modulus of the inner membrane to a greater extent. The enhanced antimicrobial efficacy of laurate over oleate was further verified by experiments with giant unilamellar vesicles, which revealed that laurate induced vesicle rupture at lower concentrations in contrast to oleate. The novel molecular insights gained from our study uncovers hitherto unexplored pathways to rationalize the development of antimicrobial formulations and therapeutics.

scholarly journals Enzymes and Mechanisms Employed by Tailed Bacteriophages to Breach the Bacterial Cell Barriers

Viruses ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 396 ◽  
Author(s):  
Sofia Fernandes ◽  
Carlos São-José
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Bacterial Cell ◽  
Cell Envelope ◽  
Genetic Material ◽  
Cell Types ◽  
Virus Multiplication ◽  
Virus Particles ◽  
Bacterial Cell Envelope ◽  
A Cell

Monoderm bacteria possess a cell envelope made of a cytoplasmic membrane and a cell wall, whereas diderm bacteria have and extra lipid layer, the outer membrane, covering the cell wall. Both cell types can also produce extracellular protective coats composed of polymeric substances like, for example, polysaccharidic capsules. Many of these structures form a tight physical barrier impenetrable by phage virus particles. Tailed phages evolved strategies/functions to overcome the different layers of the bacterial cell envelope, first to deliver the genetic material to the host cell cytoplasm for virus multiplication, and then to release the virion offspring at the end of the reproductive cycle. There is however a major difference between these two crucial steps of the phage infection cycle: virus entry cannot compromise cell viability, whereas effective virion progeny release requires host cell lysis. Here we present an overview of the viral structures, key protein players and mechanisms underlying phage DNA entry to bacteria, and then escape of the newly-formed virus particles from infected hosts. Understanding the biological context and mode of action of the phage-derived enzymes that compromise the bacterial cell envelope may provide valuable information for their application as antimicrobials.

scholarly journals A secreted NlpC/P60 endopeptidase from Photobacterium damselae subsp. piscicida cleaves the peptidoglycan of potentially competing bacteria

2020 ◽  
Author(s):  
Johnny Lisboa ◽  
Cassilda Pereira ◽  
Aline Rifflet ◽  
Juan Ayala ◽  
Mateus S. Terceti ◽  
...  
Keyword(s):  
Cell Wall ◽  
Marine Fish ◽  
High Mortality ◽  
Bacterial Cell ◽  
Structural Integrity ◽  
Cell Envelope ◽  
Bacterial Cell Wall ◽  
Warm Water ◽  
Gram Negative ◽  
Photobacterium Damselae

ABSTRACTPeptidoglycan (PG) is a major component of the bacterial cell wall, forming a mesh-like structure enwrapping the bacteria that is essential for maintaining structural integrity and providing support for anchoring other components of the cell envelope. PG biogenesis is highly dynamic and requires multiple enzymes, including several hydrolases that cleave glycosidic or amide bonds in the PG. Here, it is described the structural and functional characterization of an NlpC/P60-containing peptidase from Photobacterium damselae subsp. piscicida (Phdp), a Gram-negative bacterium that causes high mortality of warm-water marine fish with great impact for the aquaculture industry. PnpA (PhotobacteriumNlpC-like Protein A) has a four-domain structure with a hydrophobic and narrow access to the catalytic center and specificity for the γ-D-glutamyl-meso-diaminopimelic acid bond. However, PnpA does not cleave the PG of Phdp and neither PG of several Gram-negative and Gram-positive bacterial species. Interestingly, it is secreted by the Phdp type II secretion system and degrades the PG of Vibrio anguillarum and V. vulnificus. This suggests that PnpA is used by Phdp to gain an advantage over bacteria that compete for the same resources or to obtain nutrients in nutrient-scarce environments. Comparison of the muropeptide composition of PG susceptible and resistant to the catalytic activity of PnpA, showed that the global content of muropeptides is similar, suggesting that susceptibility to PnpA is determined by the three-dimensional organization of the muropeptides in the PG.IMPORTANCEPeptidoglycan (PG) is a major component of the bacterial cell wall formed by long chains of two alternating sugars interconnected by short peptides, originating a mesh-like structure that enwraps the bacterial cell. Although PG provides structural integrity and support for anchoring other components of the cell envelope, it is constantly being remodeled through the action of specific enzymes that cleave or joint its components. Here, it is shown that Photobacterium damselae subsp. piscicida, a bacterium that causes high mortality in warm-water marine fish, produces PnpA, an enzyme that is secreted into the environment and is able to cleave the PG of potentially competing bacteria, either for gaining competitive advantages and/or to get nutrients. The specificity of PnpA to the PG of some bacteria and its inability to cleave others may be explained by differences in the structure of the PG mesh and not by different muropeptide composition.

Role of bacterial cell wall proteinase in antihypertension

2002 ◽  
Vol 22 (1-2) ◽  
pp. 209-222 ◽  
Author(s):  
Bénédicte Flambard
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Bacterial Cell Wall
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