scholarly journals Regulation of d-Alanyl-Lipoteichoic Acid Biosynthesis in Streptococcus agalactiae Involves a Novel Two-Component Regulatory System

2001 ◽  
Vol 183 (21) ◽  
pp. 6324-6334 ◽  
Author(s):  
Claire Poyart ◽  
Marie Cécile Lamy ◽  
Claire Boumaila ◽  
Franz Fiedler ◽  
Patrick Trieu-Cuot
Keyword(s):  
Amino Acid ◽  
Streptococcus Agalactiae ◽  
Response Regulator ◽  
Regulatory System ◽  
Lipoteichoic Acid ◽  
Kanamycin Resistance ◽  
Gram Positive ◽  
Environmental Signals ◽  
Gram Positive Bacteria ◽  
Insertional Inactivation

ABSTRACT The dlt operon of gram-positive bacteria comprises four genes (dltA, dltB, dltC, and dltD) that catalyze the incorporation of d-alanine residues into the lipoteichoic acids (LTAs). In this work, we characterized thedlt operon of Streptococcus agalactiae, which, in addition to the dltA to dltD genes, included two regulatory genes, designated dltR and dltS, located upstream of dltA. The dltR gene encodes a 224-amino-acid putative response regulator belonging to the OmpR family of regulatory proteins. The dltS gene codes for a 395-amino-acid putative histidine kinase thought to be involved in the sensing of environmental signals. The dlt operon ofS. agalactiae is mainly transcribed from the P dltR promoter, which directs synthesis of a 6.5-kb transcript encompassing dltR, dltS, dltA, dltB, dltC, and dltD, and from a weaker promoter, P dltA , which is located in the 3′ extremity ofdltS. We demonstrate that P dltR , but not P dlA , is activated by DltR in the presence of DltS in d-Ala-deficient LTA mutants resulting from insertional inactivation of the dltA gene, which encodes the cytoplasmic d-alanine-d-alanyl carrier ligase DltA. Expression of the dlt operon does not require DltR and DltS, since the basal activity of P dltR is high, being 20-fold that of the constitutive promoter P aphA-3 which directs synthesis of the kanamycin resistance gene aphA-3 in various gram-positive bacteria. We hypothesize that the role of DltR and DltS in the control of expression of the dlt operon is to maintain the level of d-Ala esters in LTAs at a constant and appropriate value whatever the environmental conditions. The DltA− mutant displayed the ability to form clumps in standing culture and exhibited an increased susceptibility to the cationic antimicrobial polypeptide colistin.

scholarly journals Gram-positive bacteria cell wall-derived lipoteichoic acid induces inflammatory alveolar bone loss through prostaglandin E production in osteoblasts

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tsukasa Tominari ◽  
Ayumi Sanada ◽  
Ryota Ichimaru ◽  
Chiho Matsumoto ◽  
Michiko Hirata ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bone Loss ◽  
Alveolar Bone ◽  
Osteoclast Differentiation ◽  
Lipoteichoic Acid ◽  
Alveolar Bone Loss ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

AbstractPeriodontitis is an inflammatory disease associated with severe alveolar bone loss and is dominantly induced by lipopolysaccharide from Gram-negative bacteria; however, the role of Gram-positive bacteria in periodontal bone resorption remains unclear. In this study, we examined the effects of lipoteichoic acid (LTA), a major cell-wall factor of Gram-positive bacteria, on the progression of inflammatory alveolar bone loss in a model of periodontitis. In coculture of mouse primary osteoblasts and bone marrow cells, LTA induced osteoclast differentiation in a dose-dependent manner. LTA enhanced the production of PGE2 accompanying the upregulation of the mRNA expression of mPGES-1, COX-2 and RANKL in osteoblasts. The addition of indomethacin effectively blocked the LTA-induced osteoclast differentiation by suppressing the production of PGE2. Using ex vivo organ cultures of mouse alveolar bone, we found that LTA induced alveolar bone resorption and that this was suppressed by indomethacin. In an experimental model of periodontitis, LTA was locally injected into the mouse lower gingiva, and we clearly detected alveolar bone destruction using 3D-μCT. We herein demonstrate a new concept indicating that Gram-positive bacteria in addition to Gram-negative bacteria are associated with the progression of periodontal bone loss.

scholarly journals Mixed liposomes containing gram-positive bacteria lipids: Lipoteichoic acid (LTA) induced structural changes

2021 ◽  
Vol 199 ◽  
pp. 111551
Author(s):  
Bhavesh Bharatiya ◽  
Gang Wang ◽  
Sarah E. Rogers ◽  
Jan Skov Pedersen ◽  
Stephen Mann ◽  
...  
Keyword(s):  
Structural Changes ◽  
Lipoteichoic Acid ◽  
Gram Positive ◽  
Gram Positive Bacteria

AgmR controls transcription of a regulon with several operons essential for ethanol oxidation in Pseudomonas aeruginosa ATCC 17933

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1851-1857 ◽  
Author(s):  
Nicole Gliese ◽  
Viola Khodaverdi ◽  
Max Schobert ◽  
Helmut Görisch
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Ethanol Oxidation ◽  
Response Regulator ◽  
Regulatory System ◽  
Pyrroloquinoline Quinone ◽  
Kanamycin Resistance ◽  
Kanamycin Resistance Cassette ◽  
Two Component ◽  
Ethanol Dehydrogenase ◽  
Oxidation System

The response regulator AgmR was identified to be involved in the regulation of the quinoprotein ethanol oxidation system of Pseudomonas aeruginosa ATCC 17933. Interruption of the agmR gene by insertion of a kanamycin-resistance cassette resulted in mutant NG3, unable to grow on ethanol. After complementation with the intact agmR gene, growth on ethanol was restored. Transcriptional lacZ fusions were used to identify four operons which are regulated by the AgmR protein: the exaA operon encodes the pyrroloquinoline quinone (PQQ)-dependent ethanol dehydrogenase, the exaBC operon encodes a soluble cytochrome c 550 and an aldehyde dehydrogenase, the pqqABCDE operon carries the PQQ biosynthetic genes, and operon exaDE encodes a two-component regulatory system which controls transcription of the exaA operon. Transcription of exaA was restored by transformation of NG3 with a pUCP20T derivative carrying the exaDE genes under lac-promoter control. These data indicate that the AgmR response regulator and the exaDE two-component regulatory system are organized in a hierarchical manner. Gene PA1977, which appears to form an operon with the agmR gene, was found to be non-essential for growth on ethanol.

scholarly journals A Two-Component Regulatory System Impacts Extracellular Membrane-Derived Vesicle Production in Group A Streptococcus

mBio ◽  
2016 ◽  
Vol 7 (6) ◽  
Author(s):  
Ulrike Resch ◽  
James Anthony Tsatsaronis ◽  
Anaïs Le Rhun ◽  
Gerald Stübiger ◽  
Manfred Rohde ◽  
...  
Keyword(s):  
Lipid Composition ◽  
Secretory Pathway ◽  
Group A Streptococcus ◽  
Regulatory System ◽  
Surface Proteins ◽  
Streptococcal Toxic Shock Syndrome ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Two Component ◽  
Group A

ABSTRACT Export of macromolecules via extracellular membrane-derived vesicles (MVs) plays an important role in the biology of Gram-negative bacteria. Gram-positive bacteria have also recently been reported to produce MVs; however, the composition and mechanisms governing vesiculogenesis in Gram-positive bacteria remain undefined. Here, we describe MV production in the Gram-positive human pathogen group A streptococcus (GAS), the etiological agent of necrotizing fasciitis and streptococcal toxic shock syndrome. M1 serotype GAS isolates in culture exhibit MV structures both on the cell wall surface and in the near vicinity of bacterial cells. A comprehensive analysis of MV proteins identified both virulence-associated protein substrates of the general secretory pathway in addition to “anchorless surface proteins.” Characteristic differences in the contents, distributions, and fatty acid compositions of specific lipids between MVs and GAS cell membrane were also observed. Furthermore, deep RNA sequencing of vesicular RNAs revealed that GAS MVs contained differentially abundant RNA species relative to bacterial cellular RNA. MV production by GAS strains varied in a manner dependent on an intact two-component system, CovRS, with MV production negatively regulated by the system. Modulation of MV production through CovRS was found to be independent of both GAS cysteine protease SpeB and capsule biosynthesis. Our data provide an explanation for GAS secretion of macromolecules, including RNAs, lipids, and proteins, and illustrate a regulatory mechanism coordinating this secretory response. IMPORTANCE Group A streptococcus (GAS) is a Gram-positive bacterial pathogen responsible for more than 500,000 deaths annually. Establishment of GAS infection is dependent on a suite of proteins exported via the general secretory pathway. Here, we show that GAS naturally produces extracellular vesicles with a unique lipid composition that are laden with proteins and RNAs. Interestingly, both virulence-associated proteins and RNA species were found to be differentially abundant in vesicles relative to the bacteria. Furthermore, we show that genetic disruption of the virulence-associated two-component regulator CovRS leads to an increase in vesicle production. This study comprehensively describes the protein, RNA, and lipid composition of GAS-secreted MVs and alludes to a regulatory system impacting this process.

scholarly journals L-Ficolin Specifically Binds to Lipoteichoic Acid, a Cell Wall Constituent of Gram-Positive Bacteria, and Activates the Lectin Pathway of Complement

2004 ◽  
Vol 172 (2) ◽  
pp. 1198-1202 ◽  
Author(s):  
Nicholas J. Lynch ◽  
Silke Roscher ◽  
Thomas Hartung ◽  
Siegfried Morath ◽  
Misao Matsushita ◽  
...  
Keyword(s):  
Cell Wall ◽  
Lipoteichoic Acid ◽  
Lectin Pathway ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Cell Wall Constituent ◽  
A Cell

scholarly journals Mechanism of Gram-positive Shock: Identification of Peptidoglycan and Lipoteichoic Acid Moieties Essential in the Induction of Nitric Oxide Synthase, Shock, and Multiple Organ Failure

1998 ◽  
Vol 188 (2) ◽  
pp. 305-315 ◽  
Author(s):  
Ken M. Kengatharan ◽  
Sjef De Kimpe ◽  
Caroline Robson ◽  
Simon J. Foster ◽  
Christoph Thiemermann
Keyword(s):  
Nitric Oxide ◽  
Multiple Organ Failure ◽  
Organ Failure ◽  
Lipoteichoic Acid ◽  
Interferon Γ ◽  
Multiple Organ ◽  
Organ Injury ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
No Formation

The incidence of septic shock caused by gram-positive bacteria has risen markedly in the last few years. It is largely unclear how gram-positive bacteria (which do not contain endotoxin) cause shock and multiple organ failure. We have discovered recently that two cell wall fragments of the pathogenic gram-positive bacterium Staphylococcus aureus, lipoteichoic acid (LTA) and peptidoglycan (PepG), synergize to cause the induction of nitric oxide (NO) formation, shock, and organ injury in the rat. We report here that a specific fragment of PepG, N-acetylglucosamine-β-[1→ 4]-N-acetylmuramyl-l-alanine–d-isoglutamine, is the moiety within the PepG polymer responsible for the synergism with LTA (or the cytokine interferon γ) to induce NO formation in the murine macrophage cell line J774.2. However, this moiety is also present in the PepG of the nonpathogenic bacterium Bacillus subtilis. We have discovered subsequently that S. aureus LTA synergizes with PepG from either bacterium to cause enhanced NO formation, shock, and organ injury in the rat, whereas the LTA from B. subtilis does not synergize with PepG of either bacterium. Thus, we propose that the structure of LTA determines the ability of a particular bacterium to cause shock and multiple organ failure (pathogenicity), while PepG acts to amplify any response induced by LTA.

Synthetic Study on Lipoteichoic Acid of Gram Positive Bacteria. I. Synthesis of Proposed Fundamental Structure ofStreptococcus pyogenesLipoteichoic Acid

1992 ◽  
Vol 65 (10) ◽  
pp. 2643-2654 ◽  
Author(s):  
Koichi Fukase ◽  
Takahiro Matsumoto ◽  
Naoko Ito ◽  
Takuya Yoshimura ◽  
Shozo Kotani ◽  
...  
Keyword(s):  
Lipoteichoic Acid ◽  
Gram Positive ◽  
Fundamental Structure ◽  
Gram Positive Bacteria

scholarly journals Antibacterial Action of Structurally Diverse Cationic Peptides on Gram-Positive Bacteria

2000 ◽  
Vol 44 (8) ◽  
pp. 2086-2092 ◽  
Author(s):  
Carol L. Friedrich ◽  
Dianne Moyles ◽  
Terry J. Beveridge ◽  
Robert E. W. Hancock
Keyword(s):  
Amino Acid ◽  
Mechanism Of Action ◽  
Cytoplasmic Membrane ◽  
Membrane Depolarization ◽  
Membrane Permeabilization ◽  
Cationic Peptides ◽  
Nuclear Condensation ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Helical Peptide

ABSTRACT Antimicrobial cationic peptides are ubiquitous in nature and are thought to be a component of the first line of defense against infectious agents. It is widely believed that the killing mechanism of these peptides on bacteria involves an interaction with the cytoplasmic membrane. Cationic peptides from different structural classes were used in experiments withStaphylococcus aureus and other medically important gram-positive bacteria to gain insight into the mechanism of action. The membrane potential-sensitive fluorophore dipropylthiacarbocyanine was used to assess the interactions of selected antimicrobial peptides with the cytoplasmic membrane of S. aureus. Study of the kinetics of killing and membrane depolarization showed that, at early time points, membrane depolarization was incomplete, even when 90% or more of the bacteria had been killed. CP26, a 26-amino-acid α-helical peptide with a high MIC against S. aureus, still had the ability to permeabilize the membrane. Cytoplasmic-membrane permeabilization was a widespread ability and an action that may be necessary for reaching an intracellular target but in itself did not appear to be the killing mechanism. Transmission electron microscopy of S. aureus andStaphylococcus epidermidis treated with CP29 (a 26-amino-acid α-helical peptide), CP11CN (a 13-amino-acid, proline- and tryptophan-rich peptide), and Bac2A-NH2 (a linearized version of the 12-amino-acid loop peptide bactenecin) showed variability in effects on bacterial structure. Mesosome-like structures were seen to develop in S. aureus, whereas cell wall effects and mesosomes were seen with S. epidermidis. Nuclear condensation and abherrent septation were occasionally seen in S. epidermidis. Our experiments indicated that these peptides vary in their mechanisms of action and that the mechanism of action likely does not solely involve cytoplasmic-membrane permeabilization.

scholarly journals Localization and Cellular Amounts of the WalRKJ (VicRKX) Two-Component Regulatory System Proteins in Serotype 2 Streptococcus pneumoniae

2010 ◽  
Vol 192 (17) ◽  
pp. 4388-4394 ◽  
Author(s):  
Kyle J. Wayne ◽  
Lok-To Sham ◽  
Ho-Ching T. Tsui ◽  
Alina D. Gutu ◽  
Skye M. Barendt ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Histidine Kinase ◽  
Cellular Localization ◽  
Immunofluorescence Microscopy ◽  
Response Regulator ◽  
Regulatory System ◽  
Respiratory Pathogen ◽  
Cell Periphery ◽  
Gram Positive Bacteria ◽  
Two Component

ABSTRACT The WalRK two-component regulatory system coordinates gene expression that maintains cell wall homeostasis and responds to antibiotic stress in low-GC Gram-positive bacteria. Phosphorylated WalR (VicR) of the major human respiratory pathogen Streptococcus pneumoniae (WalR Spn ) positively regulates transcription of several surface virulence genes and, most critically, pcsB, which encodes an essential cell division protein. Despite numerous studies of several species, little is known about the signals sensed by the WalK histidine kinase or the function of the WalJ ancillary protein encoded in the walRKSpn operon. To better understand the functions of the WalRKJ Spn proteins in S. pneumoniae, we performed experiments to determine their cellular localization and amounts. In contrast to WalK from Bacillus subtilis (WalK Bsu ), which is localized at division septa, immunofluorescence microscopy showed that WalK Spn is distributed throughout the cell periphery. WalJ Spn is also localized to the cell surface periphery, whereas WalR Spn was found to be localized in the cytoplasm around the nucleoid. In fractionation experiments, WalR Spn was recovered from the cytoplasmic fraction, while WalK Spn and the majority of WalJ Spn were recovered from the cell membrane fraction. This fractionation is consistent with the localization patterns observed. Lastly, we determined the cellular amounts of WalRKJ Spn by quantitative Western blotting. The WalR Spn response regulator is relatively abundant and present at levels of ≈6,200 monomers per cell, which are ≈14-fold greater than the amount of the WalK Spn histidine kinase, which is present at ≈460 dimers (920 monomers) per cell. We detected ≈1,200 monomers per cell of WalJ Spn ancillary protein, similar to the amount of WalK Spn .

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