scholarly journals The role of Listeria monocytogenes cell wall surface anchor protein LapB in virulence, adherence, and intracellular replication

2016 ◽  
Vol 92 ◽  
pp. 19-25 ◽  
Author(s):  
Swetha Reddy ◽  
Ali Akgul ◽  
Attila Karsi ◽  
Hossam Abdelhamed ◽  
Robert W. Wills ◽  
...  
2011 ◽  
Vol 100 (3) ◽  
pp. 163a
Author(s):  
Biplab C. Paul ◽  
Amira E. El-Ganiny ◽  
Mariam Abbas ◽  
Susan G.W. Kaminskyj ◽  
Tanya E.S. Dahms

2012 ◽  
Vol 194 (23) ◽  
pp. 6498-6506 ◽  
Author(s):  
Marcel R. Eugster ◽  
Martin J. Loessner

ABSTRACTThe C-terminal cell wall binding domains (CBDs) of phage endolysins direct the enzymes to their binding ligands on the bacterial cell wall with high affinity and specificity. TheListeria monocytogenesPly118, Ply511, and PlyP40 endolysins feature related CBDs which recognize the directly cross-linked peptidoglycan backbone structure ofListeria. However, decoration with fluorescently labeled CBDs primarily occurs at the poles and septal regions of the rod-shaped cells. To elucidate the potential role of secondary cell wall-associated carbohydrates such as the abundant wall teichoic acid (WTA) on this phenomenon, we investigated CBD binding usingL. monocytogenesserovar 1/2 and 4 cells deficient in WTA. Mutants were obtained by deletion of two redundanttagOhomologues, whose products catalyze synthesis of the WTA linkage unit. While inactivation of eithertagO1(EGDelmo0959) ortagO2(EGDelmo2519) alone did not affect WTA content, removal of both alleles following conditional complementation yielded WTA-deficientListeriacells. Substitution oftagOfrom an isopropyl-β-d-thiogalactopyranoside-inducible single-copy integration vector restored the original phenotype. Although WTA-deficient cells are viable, they featured severe growth inhibition and an unusual coccoid morphology. In contrast to CBDs from otherListeriaphage endolysins which directly utilize WTA as binding ligand, the data presented here show that WTAs are not required for attachment of CBD118, CBD511, and CBDP40. Instead, lack of the cell wall polymers enables unrestricted spatial access of CBDs to the cell wall surface, indicating that the abundant WTA can negatively regulate sidewall localization of the cell wall binding domains.


2004 ◽  
Vol 186 (7) ◽  
pp. 1972-1982 ◽  
Author(s):  
Hélène Bierne ◽  
Caroline Garandeau ◽  
M. Graciela Pucciarelli ◽  
Christophe Sabet ◽  
Salete Newton ◽  
...  

ABSTRACT Sortases are transamidases that covalently link proteins to the peptidoglycan of gram-positive bacteria. The genome of the pathogenic bacterium Listeria monocytogenes encodes two sortases genes, srtA and srtB. The srtA gene product anchors internalin and some other LPXTG-containing proteins to the listerial surface. Here, we focus on the role of the second sortase, SrtB. Whereas SrtA acts on most of the proteins in the peptidoglycan fraction, SrtB appears to target minor amounts of surface polypeptides. We identified one of the SrtB-anchored proteins as the virulence factor SvpA, a surface-exposed protein which does not contain the LPXTG motif. Therefore, as in Staphylococcus aureus, the listerial SrtB represents a second class of sortase in L. monocytogenes, involved in the attachment of a subset of proteins to the cell wall, most likely by recognizing an NXZTN sorting motif. The ΔsrtB mutant strain does not have defects in bacterial entry, growth, or motility in tissue-cultured cells and does not show attenuated virulence in mice. SrtB-mediated anchoring could therefore be required to anchor surface proteins involved in the adaptation of this microorganism to different environmental conditions.


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

2020 ◽  
Vol 21 (10) ◽  
pp. 980-989
Author(s):  
Sampath Shobana ◽  
Sunderam Veena ◽  
S.S.M. Sameer ◽  
K. Swarnalakshmi ◽  
L.A. Vishal

Aims: To evaluate the antibacterial activity of Artocarpus hirsutus mediated seed extract for nanoparticle synthesis. Background: Gastrointestinal bacteria are known for causing deadly infections in humans. They also possess multi-drug resistance and interfere with clinical treatments. Applied nanotechnology has been known to combat such infectious agents with little interference from their special attributes. Here we synthesize silver nanoparticles from Artocarpus hirsutus seed extract against two gastro-intestinal bacterial species: Enterobacter aerogenes and Listeria monocytogenes. Objective: To collect, dry, and process seeds of Artocarpus hirsutus for nanoparticle synthesis. To evaluate the morphological interaction of silver nanoparticles with bacteria. Methods: Artocarpus hirsutus seeds were collected and processed and further silver nanoparticles were synthesized by the co-precipitation method. The synthesized nanoparticles were characterized using XRD, UV, FTIR, and SEM. These nanoparticles were employed to study the antibacterial activity of nanoparticles against Enterobacter aerogenes and Listeria monocytogenes using well diffusion method. Further, morphological interaction of silver nanoparticles on bacteria was studied using SEM. Result: Silver nanoparticles were synthesized using Artocarpus hirsutus seed extract and characterization studies confirmed that silver nanoparticles were spherical in shape with 25-40 nm size. Antibacterial study exhibited better activity against Enterobacter aerogenes with a maximum zone of inhibition than on Listeria monocytogenes. SEM micrographs indicated that Enterobacter aerogenes bacteria were more susceptible to silver nanoparticles due to the absence of cell wall. Also, the size and charge of silver nanoparticles enable easy penetration of the bacterial cell wall. Conclusion: In this study, silver nanoparticles were synthesized using the seed extract of Artocarpus hirsutus for the first time exploiting the fact that Moraceae species have high phytonutrient content which aided in nanoparticle synthesis. This nanoparticle can be employed for large scale synthesis which when coupled with the pharmaceutical industry can be used to overcome the problems associated with conventional antibiotics to treat gastrointestinal bacteria.


2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Fangwei Yu ◽  
Shenyun Wang ◽  
Wei Zhang ◽  
Hong Wang ◽  
Li Yu ◽  
...  

Abstract The members of myeloblastosis transcription factor (MYB TF) family are involved in the regulation of biotic and abiotic stresses in plants. However, the role of MYB TF in phosphorus remobilization remains largely unexplored. In the present study, we show that an R2R3 type MYB transcription factor, MYB103, is involved in phosphorus (P) remobilization. MYB103 was remarkably induced by P deficiency in cabbage (Brassica oleracea var. capitata L.). As cabbage lacks the proper mutant for elucidating the mechanism of MYB103 in P deficiency, another member of the crucifer family, Arabidopsis thaliana was chosen for further study. The transcript of its homologue AtMYB103 was also elevated in response to P deficiency in A. thaliana, while disruption of AtMYB103 (myb103) exhibited increased sensitivity to P deficiency, accompanied with decreased tissue biomass and soluble P concentration. Furthermore, AtMYB103 was involved in the P reutilization from cell wall, as less P was released from the cell wall in myb103 than in wildtype, coinciding with the reduction of ethylene production. Taken together, our results uncover an important role of MYB103 in the P remobilization, presumably through ethylene signaling.


2021 ◽  
Vol 9 (6) ◽  
pp. 1323
Author(s):  
Etai Boichis ◽  
Nadejda Sigal ◽  
Ilya Borovok ◽  
Anat A. Herskovits

Infection of mammalian cells by Listeria monocytogenes (Lm) was shown to be facilitated by its phage elements. In a search for additional phage remnants that play a role in Lm’s lifecycle, we identified a conserved locus containing two XRE regulators and a pair of genes encoding a secreted metzincin protease and a lipoprotein structurally similar to a TIMP-family metzincin inhibitor. We found that the XRE regulators act as a classic CI/Cro regulatory switch that regulates the expression of the metzincin and TIMP-like genes under intracellular growth conditions. We established that when these genes are expressed, their products alter Lm morphology and increase its sensitivity to phage mediated lysis, thereby enhancing virion release. Expression of these proteins also sensitized the bacteria to cell wall targeting compounds, implying that they modulate the cell wall structure. Our data indicate that these effects are mediated by the cleavage of the TIMP-like protein by the metzincin, and its subsequent release to the extracellular milieu. While the importance of this locus to Lm pathogenicity remains unclear, the observation that this phage-associated protein pair act upon the bacterial cell wall may hold promise in the field of antibiotic potentiation to combat antibiotic resistant bacterial pathogens.


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