scholarly journals Dynamic Distribution of the SecA and SecY Translocase Subunits and Septal Localization of the HtrA Surface Chaperone/Protease during Streptococcus pneumoniae D39 Cell Division

mBio ◽  
2011 ◽  
Vol 2 (5) ◽  
Author(s):  
Ho-Ching Tiffany Tsui ◽  
Susan K. Keen ◽  
Lok-To Sham ◽  
Kyle J. Wayne ◽  
Malcolm E. Winkler
Keyword(s):  
Cell Division ◽  
Streptococcus Pneumoniae ◽  
Stationary Phase ◽  
Streptococcus Pyogenes ◽  
Phospholipid Content ◽  
Gram Positive ◽  
General Role ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Dividing Cells

ABSTRACT The Sec translocase pathway is the major route for protein transport across and into the cytoplasmic membrane of bacteria. Previous studies reported that the SecA translocase ATP-binding subunit and the cell surface HtrA protease/chaperone formed a single microdomain, termed “ExPortal,” in some species of ellipsoidal (ovococcus) Gram-positive bacteria, including Streptococcus pyogenes. To investigate the generality of microdomain formation, we determined the distribution of SecA and SecY by immunofluorescent microscopy in Streptococcus pneumoniae (pneumococcus), which is an ovococcus species evolutionarily distant from S. pyogenes. In the majority (≥75%) of exponentially growing cells, S. pneumoniae SecA (SecA Spn ) and SecY Spn located dynamically in cells at different stages of division. In early divisional cells, both Sec subunits concentrated at equators, which are future sites of constriction. Further along in division, SecA Spn and SecY Spn remained localized at mid-cell septa. In late divisional cells, both Sec subunits were hemispherically distributed in the regions between septa and the future equators of dividing cells. In contrast, the HtrA Spn homologue localized to the equators and septa of most (>90%) dividing cells, whereas the SrtA Spn sortase located over the surface of cells in no discernable pattern. This dynamic pattern of Sec distribution was not perturbed by the absence of flotillin family proteins, but was largely absent in most cells in early stationary phase and in ∆cls mutants lacking cardiolipin synthase. These results do not support the existence of an ExPortal microdomain in S. pneumoniae. Instead, the localization of the pneumococcal Sec translocase depends on the stage of cell division and anionic phospholipid content. IMPORTANCE Two patterns of Sec translocase distribution, an ExPortal microdomain in certain ovococcus-shaped species like Streptococcus pyogenes and a spiral pattern in rod-shaped species like Bacillus subtilis, have been reported for Gram-positive bacteria. This study provides evidence for a third pattern of Sec localization in the ovococcus human pathogen Streptococcus pneumoniae. The SecA motor and SecY channel subunits of the Sec translocase localize dynamically to different places in the mid-cell region during the division cycle of exponentially growing, but not stationary-phase, S. pneumoniae. Unexpectedly, the S. pneumoniae HtrA (HtrA Spn ) protease/chaperone principally localizes to cell equators and division septa. The coincident localization of SecA Spn , SecY Spn , and HtrA Spn to regions of peptidoglycan (PG) biosynthesis in unstressed, growing cells suggests that the pneumococcal Sec translocase directs assembly of the PG biosynthesis apparatus to regions where it is needed during division and that HtrA Spn may play a general role in quality control of proteins exported by the Sec translocase.

scholarly journals Recognition of Streptococcus pneumoniae and Muramyl Dipeptide by NOD2 Results in Potent Induction of MMP-9, Which Can Be Controlled by Lipopolysaccharide Stimulation

2014 ◽  
Vol 82 (12) ◽  
pp. 4952-4958 ◽  
Author(s):  
Marloes Vissers ◽  
Yvonne Hartman ◽  
Laszlo Groh ◽  
Dirk J. de Jong ◽  
Marien I. de Jonge ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Mononuclear Cells ◽  
Muramyl Dipeptide ◽  
Tissue Inhibitor Of Metalloproteinase ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Potent Inducer ◽  
Gram Negative ◽  
Content Type ◽  
Gram Positive Bacteria

ABSTRACTMatrix metallopeptidase 9 (MMP-9) is a protease involved in the degradation of extracellular matrix collagen. Evidence suggests that MMP-9 is involved in pathogenesis duringStreptococcus pneumoniaeinfection. However, not much is known about the induction of MMP-9 and the regulatory processes involved. We show here that the Gram-positive bacteria used in this study induced large amounts of MMP-9, in contrast to the Gram-negative bacteria that were used. An important pathogen-associated molecular pattern (PAMP) for Gram-positive bacteria is muramyl dipeptide (MDP). MDP is a very potent inducer of MMP-9 and showed a dose-dependent MMP-9 induction. Experiments using peripheral blood mononuclear cells (PBMCs) from Crohn's disease patients with nonfunctional NOD2 showed that MMP-9 induction byStreptococcus pneumoniaeand MDP is NOD2 dependent. Increasing amounts of lipopolysaccharide (LPS), an important PAMP for Gram-negative bacteria, resulted in decreasing amounts of MMP-9. Moreover, the induction of MMP-9 by MDP could be counteracted by simultaneously adding LPS. The inhibition of MMP-9 expression by LPS was found to be regulated posttranscriptionally, independently of tissue inhibitor of metalloproteinase 1 (TIMP-1), an endogenous inhibitor of MMP-9. Collectively, these data show thatStreptococcus pneumoniaeis able to induce large amounts of MMP-9. These high MMP-9 levels are potentially involved inStreptococcus pneumoniaepathogenesis.

scholarly journals Postantibiotic Suppression of Growth of Erythromycin A-Susceptible and -Resistant Gram-Positive Bacteria by the Ketolides Telithromycin (HMR 3647) and HMR 3004

2000 ◽  
Vol 44 (6) ◽  
pp. 1749-1753 ◽  
Author(s):  
Wendy J. Munckhof ◽  
Glenn Borlace ◽  
John D. Turnidge
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Streptococcus Pyogenes ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Resistant Strains ◽  
Erythromycin A

ABSTRACT We investigated the in vitro postantibiotic effects (PAEs) of the ketolides telithromycin (HMR 3647) and HMR 3004 and analyzed the results using the sigmoid E max model. Mean maximum telithromycin PAEs against erythromycin A-susceptible strains of Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus pneumoniae were 3.7, 8.9, and 9.7 h, respectively, while maximum PAEs for erythromycin A-resistant strains were much shorter. Mean maximum HMR 3004 PAEs were 3.2 to 4.4 h for all species.

scholarly journals Roles of the Essential Protein FtsA in Cell Growth and Division in Streptococcus pneumoniae

2016 ◽  
Vol 199 (3) ◽  
Author(s):  
Andrea Mura ◽  
Daniela Fadda ◽  
Amilcar J. Perez ◽  
Madeline L. Danforth ◽  
Daniela Musu ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Cell Growth ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Content Type ◽  
Ring Assembly ◽  
Dividing Cells ◽  
Division Process ◽  
Synthetically Lethal ◽  
Partial Depletion

ABSTRACT Streptococcus pneumoniae is an ovoid-shaped Gram-positive bacterium that grows by carrying out peripheral and septal peptidoglycan (PG) synthesis, analogous to model bacilli, such as Escherichia coli and Bacillus subtilis. In the model bacilli, FtsZ and FtsA proteins assemble into a ring at midcell and are dedicated to septal PG synthesis but not peripheral PG synthesis; hence, inactivation of FtsZ or FtsA results in long filamentous cells unable to divide. Here, we demonstrate that FtsA and FtsZ colocalize at midcell in S. pneumoniae and that partial depletion of FtsA perturbs septum synthesis, resulting in elongated cells with multiple FtsZ rings that fail to complete septation. Unexpectedly, complete depletion of FtsA resulted in the delocalization of FtsZ rings and ultimately cell ballooning and lysis. In contrast, depletion or deletion of gpsB and sepF, which in B. subtilis are synthetically lethal with ftsA, resulted in enlarged and elongated cells with multiple FtsZ rings, with deletion of sepF mimicking partial depletion of FtsA. Notably, cell ballooning was not observed, consistent with later recruitment of these proteins to midcell after Z-ring assembly. The overproduction of FtsA stimulates septation and suppresses the cell division defects caused by the deletion of sepF and gpsB under some conditions, supporting the notion that FtsA shares overlapping functions with GpsB and SepF at later steps in the division process. Our results indicate that, in S. pneumoniae, both GpsB and SepF are involved in septal PG synthesis, whereas FtsA and FtsZ coordinate both peripheral and septal PG synthesis and are codependent for localization at midcell. IMPORTANCE Streptococcus pneumoniae (pneumococcus) is a clinically important human pathogen for which more therapies against unexploited essential targets, like cell growth and division proteins, are needed. Pneumococcus is an ovoid-shaped Gram-positive bacterium with cell growth and division properties that have important distinctions from those of rod-shaped bacteria. Gaining insights into these processes can thus provide valuable information to develop novel antimicrobials. Whereas rods use distinctly localized protein machines at different cellular locations to synthesize peripheral and septal peptidoglycans, we present evidence that S. pneumoniae organizes these two machines at a single location in the middle of dividing cells. Here, we focus on the properties of the actin-like protein FtsA as an essential orchestrator of peripheral and septal growth in this bacterium.

scholarly journals ¡vIVA la DivIVA!

2019 ◽  
Vol 201 (21) ◽  
Author(s):  
Lauren R. Hammond ◽  
Maria L. White ◽  
Prahathees J. Eswara
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Parental Cell ◽  
Model Organisms ◽  
Posttranslational Regulation ◽  
Bacterial Cell Division ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Division Cell

ABSTRACT Reproduction in the bacterial kingdom predominantly occurs through binary fission—a process in which one parental cell is divided into two similarly sized daughter cells. How cell division, in conjunction with cell elongation and chromosome segregation, is orchestrated by a multitude of proteins has been an active area of research spanning the past few decades. Together, the monumental endeavors of multiple laboratories have identified several cell division and cell shape regulators as well as their underlying regulatory mechanisms in rod-shaped Escherichia coli and Bacillus subtilis, which serve as model organisms for Gram-negative and Gram-positive bacteria, respectively. Yet our understanding of bacterial cell division and morphology regulation is far from complete, especially in noncanonical and non-rod-shaped organisms. In this review, we focus on two proteins that are highly conserved in Gram-positive organisms, DivIVA and its homolog GpsB, and attempt to summarize the recent advances in this area of research and discuss their various roles in cell division, cell growth, and chromosome segregation in addition to their interactome and posttranslational regulation.

scholarly journals Multistep Resistance Development Studies of Ceftaroline in Gram-Positive and -Negative Bacteria

2011 ◽  
Vol 55 (5) ◽  
pp. 2344-2351 ◽  
Author(s):  
Catherine Clark ◽  
Pamela McGhee ◽  
Peter C. Appelbaum ◽  
Klaudia Kosowska-Shick
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Streptococcus Pyogenes ◽  
Moraxella Catarrhalis ◽  
Active Component ◽  
Gram Positive ◽  
Resistance Development ◽  
Ceftaroline Fosamil ◽  
Content Type ◽  
The One

ABSTRACTCeftaroline, the active component of the prodrug ceftaroline fosamil, is a novel broad-spectrum cephalosporin with bactericidal activity against Gram-positive and -negative isolates. This study evaluated the potential for ceftaroline and comparator antibiotics to select for clones ofStreptococcus pneumoniae,Streptococcus pyogenes,Haemophilus influenzae,Moraxella catarrhalis,Klebsiella pneumoniae,Staphylococcus aureus, andEnterococcus faecaliswith elevated MICs.S. pneumoniaeandS. pyogenesisolates in the present study were highly susceptible to ceftaroline (MIC range, 0.004 to 0.25 μg/ml). No streptococcal strains yielded ceftaroline clones with increased MICs (defined as an increase in MIC of >4-fold) after 50 daily passages. Ceftaroline MICs forH. influenzaeandM. catarrhaliswere 0.06 to 2 μg/ml for four strains and 8 μg/ml for a β-lactamase-positive, efflux-positiveH. influenzaewith a mutation in L22. OneH. influenzaeclone with an increased ceftaroline MIC (quinolone-resistant, β-lactamase-positive) was recovered after 20 days. The ceftaroline MIC for this isolate increased 16-fold, from 0.06 to 1 μg/ml. MICs forS. aureusranged from 0.25 to 1 μg/ml. NoS. aureusisolates tested with ceftaroline had clones with increased MIC (>4-fold) after 50 passages. TwoE. faecalisisolates tested had ceftaroline MICs increased from 1 to 8 μg/ml after 38 days and from 4 to 32 μg/ml after 41 days, respectively. The parental ceftaroline MIC for the oneK. pneumoniaeextended-spectrum β-lactamase-negative isolate tested was 0.5 μg/ml and did not change after 50 daily passages.

scholarly journals Interdependent YpsA- and YfhS-Mediated Cell Division and Cell Size Phenotypes in Bacillus subtilis

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Robert S. Brzozowski ◽  
Brooke R. Tomlinson ◽  
Michael D. Sacco ◽  
Judy J. Chen ◽  
Anika N. Ali ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Cell Size ◽  
Unknown Function ◽  
Suppressor Mutation ◽  
Gram Positive ◽  
Content Type ◽  
Suppressor Mutations ◽  
Extragenic Suppressor ◽  
Cell Division Inhibition

ABSTRACT Although many bacterial cell division factors have been uncovered over the years, evidence from recent studies points to the existence of yet-to-be-discovered factors involved in cell division regulation. Thus, it is important to identify factors and conditions that regulate cell division to obtain a better understanding of this fundamental biological process. We recently reported that in the Gram-positive organisms Bacillus subtilis and Staphylococcus aureus, increased production of YpsA resulted in cell division inhibition. In this study, we isolated spontaneous suppressor mutations to uncover critical residues of YpsA and the pathways through which YpsA may exert its function. Using this technique, we were able to isolate four unique intragenic suppressor mutations in ypsA (E55D, P79L, R111P, and G132E) that rendered the mutated YpsA nontoxic upon overproduction. We also isolated an extragenic suppressor mutation in yfhS, a gene that encodes a protein of unknown function. Subsequent analysis confirmed that cells lacking yfhS were unable to undergo filamentation in response to YpsA overproduction. We also serendipitously discovered that YfhS may play a role in cell size regulation. Finally, we provide evidence showing a mechanistic link between YpsA and YfhS. IMPORTANCE Bacillus subtilis is a rod-shaped Gram-positive model organism. The factors fundamental to the maintenance of cell shape and cell division are of major interest. We show that increased expression of ypsA results in cell division inhibition and impairment of colony formation on solid medium. Colonies that do arise possess compensatory suppressor mutations. We have isolated multiple intragenic (within ypsA) mutants and an extragenic suppressor mutant. Further analysis of the extragenic suppressor mutation led to a protein of unknown function, YfhS, which appears to play a role in regulating cell size. In addition to confirming that the cell division phenotype associated with YpsA is disrupted in a yfhS-null strain, we also discovered that the cell size phenotype of the yfhS knockout mutant is abolished in a strain that also lacks ypsA. This highlights a potential mechanistic link between these two proteins; however, the underlying molecular mechanism remains to be elucidated.

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 In Vitro and In Vivo Activities of DA-7867, a New Oxazolidinone, against Aerobic Gram-Positive Bacteria

2005 ◽  
Vol 49 (6) ◽  
pp. 2498-2500 ◽  
Author(s):  
Eun Jeong Yoon ◽  
Yeong Woo Jo ◽  
Sung Hak Choi ◽  
Tae Ho Lee ◽  
Jae Keol Rhee ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Infection Models ◽  
Vancomycin Resistant

ABSTRACT In vitro and in vivo activities of DA-7867 were assessed against methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and penicillin-resistant Streptococcus pneumoniae. All isolates were inhibited by DA-7867 at ≤0.78 μg/ml, a four-times-lower concentration than that of inhibition by linezolid. For murine infection models, DA-7867 also exhibited greater efficacy than linezolid against all isolates tested.

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.

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