scholarly journals Extracellular Vesicle Biogenesis and Functions in Gram-Positive Bacteria

2020 ◽  
Vol 88 (12) ◽  
Author(s):  
Paul Briaud ◽  
Ronan K. Carroll
Keyword(s):  
Lipid Bilayers ◽  
Membrane Vesicles ◽  
Cell Interaction ◽  
Extracellular Vesicle ◽  
Wall Structure ◽  
Future Research ◽  
Gram Positive ◽  
Content Type ◽  
Bacterial Physiology ◽  
Gram Positive Bacteria

ABSTRACT Extracellular vesicles (EVs) are membrane-derived lipid bilayers secreted by bacteria and eukaryotic cells. Bacterial membrane vesicles were discovered over 60 years ago and have been extensively studied in Gram-negative bacteria. During their production, EVs are loaded with proteins, nucleic acids, and various compounds that are subsequently released into the environment. Depending on the packaged cargo, EVs have a broad spectrum of action and are involved in pathogenesis, antibiotic resistance, nutrient uptake, and nucleic acid transfer. Due to differences in cell wall structure, EVs in Gram-positive bacteria have been disregarded for decades, and our understanding of their biogenesis and host cell interaction is incomplete. Recently, studies on bacteria such as Staphylococcus aureus, Streptococcus spp., Bacillus subtilis, and Mycobacterium spp. have demonstrated EV production in Gram-positive bacteria and shown the great importance EVs have in Gram-positive bacterial physiology and disease progression. Here, we review the latest findings on the biogenesis and functions of EVs from Gram-positive bacteria and identify key areas for future research.

scholarly journals Identification of Conserved and Species-Specific Functions of the Listeria monocytogenes PrsA2 Secretion Chaperone

2015 ◽  
Vol 83 (10) ◽  
pp. 4028-4041 ◽  
Author(s):  
Laty A. Cahoon ◽  
Nancy E. Freitag
Keyword(s):  
Listeria Monocytogenes ◽  
Protein Translocation ◽  
Functional Complementation ◽  
Broth Culture ◽  
Cell Physiology ◽  
Gram Positive ◽  
Content Type ◽  
Bacterial Physiology ◽  
Gram Positive Bacteria ◽  
Species Specific

The Gram-positive bacteriumListeria monocytogenesis a facultative intracellular pathogen that relies on the regulated secretion and activity of a variety of proteins that sustain life within diverse environments. PrsA2 has recently been identified as a secreted peptidyl-prolylcis/transisomerase and chaperone that is dispensable for bacterial growth in broth culture but essential forL. monocytogenesvirulence. Following host infection, PrsA2 contributes to the proper folding and activity of secreted proteins that are required for bacterial replication within the host cytosol and for bacterial spread to adjacent cells. PrsA2 is one member of a family of Gram-positive secretion chaperones that appear to play important roles in bacterial physiology; however, it is not known how these proteins recognize their substrate proteins or the degree to which their function is conserved across diverse Gram-positive species. We therefore examined PrsA proteins encoded by a variety of Gram-positive bacteria for functional complementation ofL. monocytogenesmutants lackingprsA2. PrsA homologues encoded byBacillus subtilis,Streptococcus pyogenes,Streptococcus pneumoniae,Streptococcus mutans,Staphylococcus aureus, andLactococcus lactiswere examined for functional complementation of a variety ofL. monocytogenesPrsA2-associated phenotypes central toL. monocytogenespathogenesis and bacterial cell physiology. Our results indicate that while selected aspects of PrsA2 function are broadly conserved among diverse Gram-positive bacteria, PrsA2 exhibits unique specificity forL. monocytogenestarget proteins required for pathogenesis. TheL. monocytogenesPrsA2 chaperone thus appears evolutionarily optimized for virulence factor secretion within the host cell cytosol while still maintaining aspects of activity relevant to more general features of Gram-positive protein translocation.

scholarly journals Immunoactive Clostridial Membrane Vesicle Production Is Regulated by a Sporulation Factor

2017 ◽  
Vol 85 (5) ◽  
Author(s):  
Nozomu Obana ◽  
Ryoma Nakao ◽  
Kyoko Nagayama ◽  
Kouji Nakamura ◽  
Hidenobu Senpuku ◽  
...  
Keyword(s):  
Membrane Vesicle ◽  
Membrane Vesicles ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Host Interaction ◽  
Sensor Kinases ◽  
Toll Like Receptor 2 ◽  
Membrane Spanning ◽  
Aspartate Residue

ABSTRACT Recently, many Gram-positive bacteria as well as Gram-negative bacteria have been reported to produce membrane vesicles (MVs), but little is known regarding the regulators involved in MV formation. We found that a Gram-positive anaerobic pathogen, Clostridium perfringens, produces MVs predominantly containing membrane proteins and cell wall components. These MVs stimulated proinflammatory cytokine production in mouse macrophage-like cells. We suggested that MVs induced interleukin-6 production through the Toll-like receptor 2 (TLR2) signaling pathway. Thus, the MV could have a role in the bacterium-host interaction and bacterial infection pathogenesis. Moreover, we found that the sporulation master regulator gene spo0A was required for vesiculogenesis. A conserved, phosphorylated aspartate residue of Spo0A was indispensable for MV production, suggesting that the phosphorylation of Spo0A triggers MV production. Multiple orphan sensor kinases necessary for sporulation were also required to maximize MV production. These findings imply that C. perfringens actively produces immunoactive MVs in response to the environment changing, as recognized by membrane-spanning sensor kinases and by modulating the phosphorylation level of Spo0A.

scholarly journals DhhP, a Cyclic di-AMP Phosphodiesterase of Borrelia burgdorferi, Is Essential for Cell Growth and Virulence

2014 ◽  
Vol 82 (5) ◽  
pp. 1840-1849 ◽  
Author(s):  
Meiping Ye ◽  
Jun-Jie Zhang ◽  
Xin Fang ◽  
Gavin B. Lawlis ◽  
Bryan Troxell ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Wild Type Strain ◽  
Wall Structure ◽  
Mammalian Host ◽  
Dependent Manner ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria

ABSTRACTCyclic di-AMP (c-di-AMP) is a recently discovered second messenger in bacteria. Most of work on c-di-AMP signaling has been done in Gram-positive bacteria, firmicutes, and actinobacteria, where c-di-AMP signaling pathways affect potassium transport, cell wall structure, and antibiotic resistance. Little is known about c-di-AMP signaling in other bacteria.Borrelia burgdorferi, the causative agent of Lyme disease, is a spirochete that has a Gram-negative dual membrane. In this study, we demonstrated thatB. burgdorferiBB0619, aDHH-DHHA1 domainprotein (herein designated DhhP), functions as c-di-AMP phosphodiesterase. Recombinant DhhP hydrolyzed c-di-AMP to pApA in a Mn2+- or Mg2+-dependent manner. In contrast to c-di-AMP phosphodiesterases reported thus far, DhhP appears to be essential forB. burgdorferigrowth bothin vitroand in the mammalian host. Inactivation of the chromosomaldhhPgene could be achieved only in the presence of a plasmid-encoded inducibledhhPgene. The conditionaldhhPmutant had a dramatic increase in intracellular c-di-AMP level in comparison to the isogenic wild-type strain. Unlike what has been observed in Gram-positive bacteria, elevated cellular c-di-AMP inB. burgdorferidid not result in an increased resistance to β-lactamase antibiotics, suggesting that c-di-AMP's functions in spirochetes differ from those in Gram-positive bacteria. In addition, thedhhPmutant was defective in induction of the σSfactor, RpoS, and the RpoS-dependent outer membrane virulence factor OspC, which uncovers an important role of c-di-AMP inB. burgdorferivirulence.

scholarly journals Staphylococcus aureus Extracellular Vesicles Carry Biologically Active β-Lactamase

2013 ◽  
Vol 57 (6) ◽  
pp. 2589-2595 ◽  
Author(s):  
Jaewook Lee ◽  
Eun-Young Lee ◽  
Si-Hyun Kim ◽  
Dae-Kyum Kim ◽  
Kyong-Su Park ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Extracellular Vesicles ◽  
Extracellular Vesicle ◽  
Biologically Active ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Heat Treated ◽  
Protease Digestion

ABSTRACTGram-positive bacteria naturally produce extracellular vesicles. However, little is known regarding the functions of Gram-positive bacterial extracellular vesicles, especially in the bacterial community. Here, we investigated the role ofStaphylococcus aureusextracellular vesicles in interbacterial communication to cope with antibiotic stress. We found thatS. aureusliberated BlaZ, a β-lactamase protein, via extracellular vesicles. These extracellular vesicles enabled other ampicillin-susceptible Gram-negative and Gram-positive bacteria to survive in the presence of ampicillin. However,S. aureusextracellular vesicles did not mediate the survival of tetracycline-, chloramphenicol-, or kanamycin-susceptible bacteria. Moreover,S. aureusextracellular vesicles did not contain theblaZgene. In addition, the heat-treatedS. aureusextracellular vesicles did not mediate the survival of ampicillin-susceptible bacteria. The β-lactamase activities ofS. aureussoluble and extracellular vesicle-associated BlaZ were similar, but only the extracellular vesicle-associated BlaZ was resistant to protease digestion, which suggests that the enzymatic activity of BlaZ in extracellular vesicles is largely protected by the vesicle structure. Our observations provide evidence of the important role ofS. aureusextracellular vesicles in antibiotic resistance, which allows the polymicrobial community to continue to evolve and prosper against antibiotics.

scholarly journals Antimicrobial Nodule-Specific Cysteine-Rich Peptides Induce Membrane Depolarization-Associated Changes in the Transcriptome of Sinorhizobium meliloti

2013 ◽  
Vol 79 (21) ◽  
pp. 6737-6746 ◽  
Author(s):  
Hilda Tiricz ◽  
Attila Szűcs ◽  
Attila Farkas ◽  
Bernadett Pap ◽  
Rui M. Lima ◽  
...  
Keyword(s):  
Stress Responses ◽  
Sinorhizobium Meliloti ◽  
Antimicrobial Agents ◽  
Cellular Functions ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Peptide Family ◽  
Wide Range ◽  
Natural Target

ABSTRACTLeguminous plants establish symbiosis with nitrogen-fixing alpha- and betaproteobacteria, collectively called rhizobia, which provide combined nitrogen to support plant growth. Members of the inverted repeat-lacking clade of legumes impose terminal differentiation on their endosymbiotic bacterium partners with the help of the nodule-specific cysteine-rich (NCR) peptide family composed of close to 600 members. Among the few tested NCR peptides, cationic ones had antirhizobial activity measured by reduction or elimination of the CFU and uptake of the membrane-impermeable dye propidium iodide. Here, the antimicrobial spectrum of two of these peptides, NCR247 and NCR335, was investigated, and their effect on the transcriptome of the natural targetSinorhizobium melilotiwas characterized. Both peptides were able to kill quickly a wide range of Gram-negative and Gram-positive bacteria; however, their spectra were only partially overlapping, and differences were found also in their efficacy on given strains, indicating that the actions of NCR247 and NCR335 might be similar though not identical. Treatment ofS. meliloticultures with either peptide resulted in a quick downregulation of genes involved in basic cellular functions, such as transcription-translation and energy production, as well as upregulation of genes involved in stress and oxidative stress responses and membrane transport. Similar changes provoked mainly in Gram-positive bacteria by antimicrobial agents were coupled with the destruction of membrane potential, indicating that it might also be a common step in the bactericidal actions of NCR247 and NCR335.

scholarly journals Restoration of Bioactive Lantibiotic Suicin from a RemnantlanLocus of Pathogenic Streptococcus suis Serotype 2

2013 ◽  
Vol 80 (3) ◽  
pp. 1062-1071 ◽  
Author(s):  
Jian Wang ◽  
Yong Gao ◽  
Kunling Teng ◽  
Jie Zhang ◽  
Shutao Sun ◽  
...  
Keyword(s):  
Gene Promoter ◽  
Streptococcus Suis ◽  
Gene Clusters ◽  
Disulfide Bridge ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
System A ◽  
Bactericidal Activities

ABSTRACTLantibiotics are ribosomally synthesized, posttranslationally modified antimicrobial peptides. Their biosynthesis genes are usually organized in gene clusters, which are mainly found in Gram-positive bacteria, including pathogenic streptococci. Three highly virulentStreptococcus suisserotype 2 strains (98HAH33, 05ZYH33, and SC84) have been shown to contain an 89K pathogenicity island. Here, on these islands, we unveiled and reannotated a putative lantibiotic locus designatedsuiwhich contains a virulence-associated two-component regulator,suiK-suiR. In silicoanalysis revealed that the putative lantibiotic modification genesuiMwas interrupted by a 7.9-kb integron and that other biosynthesis-related genes contained various frameshift mutations. By reconstituting the intactsuiMinEscherichia colitogether with a semi-in vitrobiosynthesis system, a putative lantibiotic named suicin was produced with bactericidal activities against a variety of Gram-positive strains, including pathogenic streptococci and vancomycin-resistant enterococci. Ring topology dissection indicated that the 34-amino-acid lantibiotic contained two methyllanthionine residues and one disulfide bridge, which render suicin in an N-terminal linear and C-terminal globular shape. To confirm the function ofsuiK-suiR, SuiR was overexpressed and purified.In vitroanalysis showed that SuiR could specifically bind to thesuiAgene promoter. Its coexpression withsuiKcould activatesuiAgene promoter inLactococcus lactisNZ9000. Conclusively, we obtained a novel lantibiotic suicin by restoring its production from the remnantsuilocus and demonstrated that virulence-associated SuiK-SuiR regulates its production.

scholarly journals Clinical Evaluation of the iCubate iC-GPC Assay for Detection of Gram-Positive Bacteria and Resistance Markers from Positive Blood Cultures

2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Paul A. Granato ◽  
Melissa M. Unz ◽  
Raymond H. Widen ◽  
Suzane Silbert ◽  
Stephen Young ◽  
...  
Keyword(s):  
Blood Culture ◽  
Staphylococcus Epidermidis ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Sequencing Method ◽  
Resistance Markers ◽  
Gram Positive Cocci

ABSTRACT The iC-GPC Assay (iCubate, Huntsville, AL) is a qualitative multiplex test for the detection of five of the most common Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Enterococcus faecalis, and Enterococcus faecium) responsible for bacterial bloodstream infections, performed directly from positive blood cultures. The assay also detects the presence of the mecA, vanA, and vanB resistance determinants. This study comparatively evaluated the performance of the iC-GPC Assay against the Verigene Gram-positive blood culture (BC-GP) assay (Luminex Corp., Austin, TX) for 1,134 patient blood culture specimens positive for Gram-positive cocci. The iC-GPC Assay had an overall percent agreement with the BC-GP assay of 95.5%. Discordant specimens were further analyzed by PCR and a bidirectional sequencing method. The results indicate that the iC-GPC Assay together with the iCubate system is an accurate and reliable tool for the detection of the five most common Gram-positive bacteria and their resistance markers responsible for bloodstream infections.

scholarly journals Activities of Oxadiazole Antibacterials against Staphylococcus aureus and Other Gram-Positive Bacteria

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Sara Ceballos ◽  
Choon Kim ◽  
Derong Ding ◽  
Shahriar Mobashery ◽  
Mayland Chang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Vancomycin Resistant ◽  
Mrsa Strains

ABSTRACT The activities of four oxadiazoles were investigated with 210 methicillin-resistant Staphylococcus aureus (MRSA) strains. MIC50 and MIC90 values of 1 to 2 and 4 μg/ml, respectively, were observed. We also evaluated the activity of oxadiazole ND-421 against other staphylococci and enterococci and in the presence of oxacillin for selected MRSA strains. The MIC for ND-421 is lowered severalfold in combination with oxacillin, as they synergize. The MIC90 of ND-421 against vancomycin-resistant enterococci is ≤1 μg/ml.

scholarly journals In Vitro Activity of Eravacycline against Gram-Positive Bacteria Isolated in Clinical Laboratories Worldwide from 2013 to 2017

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Ian Morrissey ◽  
Stephen Hawser ◽  
Sibylle H. Lob ◽  
James A. Karlowsky ◽  
Matteo Bassetti ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Microdilution Method ◽  
Clinical Laboratories ◽  
Broth Microdilution Method ◽  
Doubling Dilution

ABSTRACT Eravacycline is a novel, fully synthetic fluorocycline antibiotic being developed for the treatment of serious infections, including those caused by resistant Gram-positive pathogens. Here, we evaluated the in vitro activities of eravacycline and comparator antimicrobial agents against a recent global collection of frequently encountered clinical isolates of Gram-positive bacteria. The CLSI broth microdilution method was used to determine in vitro MIC data for isolates of Enterococcus spp. (n = 2,807), Staphylococcus spp. (n = 4,331), and Streptococcus spp. (n = 3,373) isolated primarily from respiratory, intra-abdominal, urinary, and skin specimens by clinical laboratories in 37 countries on three continents from 2013 to 2017. Susceptibilities were interpreted using both CLSI and EUCAST breakpoints. There were no substantive differences (a >1-doubling-dilution increase or decrease) in eravacycline MIC90 values for different species/organism groups over time or by region. Eravacycline showed MIC50 and MIC90 results of 0.06 and 0.12 μg/ml, respectively, when tested against Staphylococcus aureus, regardless of methicillin susceptibility. The MIC90 values of eravacycline for Staphylococcus epidermidis and Staphylococcus haemolyticus were equal (0.5 μg/ml). The eravacycline MIC90s for Enterococcus faecalis and Enterococcus faecium were 0.06 μg/ml and were within 1 doubling dilution regardless of the vancomycin susceptibility profile. Eravacycline exhibited MIC90 results of ≤0.06 μg/ml when tested against Streptococcus pneumoniae and beta-hemolytic and viridans group streptococcal isolates. In this surveillance study, eravacycline demonstrated potent in vitro activity against frequently isolated clinical isolates of Gram-positive bacteria (Enterococcus, Staphylococcus, and Streptococcus spp.), including isolates collected over a 5-year period (2013 to 2017), underscoring its potential benefit in the treatment of infections caused by common Gram-positive pathogens.

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