scholarly journals Impact of Moderate Temperature Changes on Neisseria meningitidis Adhesion Phenotypes and Proteome

2016 ◽  
Vol 84 (12) ◽  
pp. 3484-3495 ◽  
Author(s):  
Martin Lappann ◽  
Andreas Otto ◽  
Madita Brauer ◽  
Dörte Becher ◽  
Ulrich Vogel ◽  
...  
Keyword(s):  
Protein Expression ◽  
Neisseria Meningitidis ◽  
Outer Membrane ◽  
Biofilm Formation ◽  
Proteome Analysis ◽  
Ambient Air ◽  
Temperature Dependent ◽  
Content Type ◽  
Temperature Changes

Neisseria meningitidis , the meningococcus, bears the potential to cause life-threatening invasive diseases, but it usually colonizes the nasopharynx without causing any symptoms. Within the nasopharynx, Neisseria meningitidis must face temperature changes depending on the ambient air temperature. Indeed, the nasopharyngeal temperature can be substantially lower than 37°C, the temperature commonly used in experimental settings. Here, we compared the levels of meningococcal biofilm formation, autoaggregation, and cellular adherence at 32°C and 37°C and found a clear increase in all these phenotypes at 32°C suggestive of a stronger in vivo colonization capability at this temperature. A comparative proteome analysis approach revealed differential protein expression levels between 32°C and 37°C, predominantly affecting the bacterial envelope. A total of 375 proteins were detected. Use of database annotation or the PSORTb algorithm predicted 49 of those proteins to be localized in the outer membrane, 21 in either the inner or outer membrane, 35 in the periplasm, 56 in the inner membrane, and 208 in the cytosol; for 6 proteins, no annotation or prediction was available. Temperature-dependent regulation of protein expression was seen particularly in the periplasm as well as in the outer and inner membranes. N eisserial h eparin b inding a ntigen (NHBA), NMB1030, and adhesin complex protein (ACP) showed the strongest upregulation at 32°C and were partially responsible for the observed temperature-dependent phenotypes. Screening of different global regulators of Neisseria meningitidis suggested that the extracytoplasmic sigma factor σ E might be involved in temperature-dependent biofilm formation. In conclusion, subtle temperature changes trigger adaptation events promoting mucosal colonization by meningococci.

scholarly journals Abrogation of Neuraminidase Reduces Biofilm Formation, Capsule Biosynthesis, and Virulence of Porphyromonas gingivalis

2011 ◽  
Vol 80 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Chen Li ◽  
Kurniyati ◽  
Bo Hu ◽  
Jiang Bian ◽  
Jianlan Sun ◽  
...  
Keyword(s):  
Porphyromonas Gingivalis ◽  
Biofilm Formation ◽  
Adult Population ◽  
Transcriptional Analysis ◽  
Wild Type ◽  
Content Type ◽  
Multiple Organs ◽  
Biochemical Analyses

ABSTRACTThe oral bacteriumPorphyromonas gingivalisis a key etiological agent of human periodontitis, a prevalent chronic disease that affects up to 80% of the adult population worldwide.P. gingivalisexhibits neuraminidase activity. However, the enzyme responsible for this activity, its biochemical features, and its role in the physiology and virulence ofP. gingivalisremain elusive. In this report, we found thatP. gingivalisencodes a neuraminidase, PG0352 (SiaPg). Transcriptional analysis showed thatPG0352is monocistronic and is regulated by a sigma70-like promoter. Biochemical analyses demonstrated that SiaPgis an exo-α-neuraminidase that cleaves glycosidic-linked sialic acids. Cryoelectron microscopy and tomography analyses revealed that thePG0352deletion mutant (ΔPG352) failed to produce an intact capsule layer. Compared to the wild type,in vitrostudies showed that ΔPG352 formed less biofilm and was less resistant to killing by the host complement.In vivostudies showed that while the wild type caused a spreading type of infection that affected multiple organs and all infected mice were killed, ΔPG352 only caused localized infection and all animals survived. Taken together, these results demonstrate that SiaPgis an important virulence factor that contributes to the biofilm formation, capsule biosynthesis, and pathogenicity ofP. gingivalis, and it can potentially serve as a new target for developing therapeutic agents againstP. gingivalisinfection.

scholarly journals Evaluation of Antibiotics Active against Methicillin-Resistant Staphylococcus aureus Based on Activity in an Established Biofilm

2016 ◽  
Vol 60 (10) ◽  
pp. 5688-5694 ◽  
Author(s):  
Daniel G. Meeker ◽  
Karen E. Beenken ◽  
Weston B. Mills ◽  
Allister J. Loughran ◽  
Horace J. Spencer ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Limit Of Detection ◽  
Relative Activity ◽  
Methicillin Resistant ◽  
Content Type ◽  
Comparable Activity ◽  
Antibiotic Delivery

ABSTRACTWe usedin vitroandin vivomodels of catheter-associated biofilm formation to compare the relative activity of antibiotics effective against methicillin-resistantStaphylococcus aureus(MRSA) in the specific context of an established biofilm. The results demonstrated that, underin vitroconditions, daptomycin and ceftaroline exhibited comparable activity relative to each other and greater activity than vancomycin, telavancin, oritavancin, dalbavancin, or tigecycline. This was true when assessed using established biofilms formed by the USA300 methicillin-resistant strain LAC and the USA200 methicillin-sensitive strain UAMS-1. Oxacillin exhibited greater activity against UAMS-1 than LAC, as would be expected, since LAC is an MRSA strain. However, the activity of oxacillin was less than that of daptomycin and ceftaroline even against UAMS-1. Among the lipoglycopeptides, telavancin exhibited the greatest overall activity. Specifically, telavancin exhibited greater activity than oritavancin or dalbavancin when tested against biofilms formed by LAC and was the only lipoglycopeptide capable of reducing the number of viable bacteria below the limit of detection. With biofilms formed by UAMS-1, telavancin and dalbavancin exhibited comparable activity relative to each other and greater activity than oritavancin. Importantly, ceftaroline was the only antibiotic that exhibited greater activity than vancomycin when testedin vivoin a murine model of catheter-associated biofilm formation. These results emphasize the need to consider antibiotics other than vancomycin, most notably, ceftaroline, for the treatment of biofilm-associatedS. aureusinfections, including by the matrix-based antibiotic delivery methods often employed for local antibiotic delivery in the treatment of these infections.

scholarly journals Pushing beyond the Envelope: the Potential Roles of OprF inPseudomonas aeruginosaBiofilm Formation and Pathogenicity

2019 ◽  
Vol 201 (18) ◽  
Author(s):  
Erin K. Cassin ◽  
Boo Shan Tseng
Keyword(s):  
Extracellular Matrix ◽  
Outer Membrane ◽  
Biofilm Formation ◽  
Matrix Protein ◽  
Cell Envelope ◽  
Outer Membrane Vesicles ◽  
Extracellular Dna ◽  
Future Research ◽  
Content Type ◽  
Biofilm Matrix

ABSTRACTThe ability ofPseudomonas aeruginosato form biofilms, which are communities of cells encased in a self-produced extracellular matrix, protects the cells from antibiotics and the host immune response. While some biofilm matrix components, such as exopolysaccharides and extracellular DNA, are relatively well characterized, the extracellular matrix proteins remain understudied. Multiple proteomic analyses of theP. aeruginosasoluble biofilm matrix and outer membrane vesicles, which are a component of the matrix, have identified OprF as an abundant matrix protein. To date, the few reports on the effects ofoprFmutations on biofilm formation are conflicting, and little is known about the potential role of OprF in the biofilm matrix. The majority of OprF studies focus on the protein as a cell-associated porin. As a component of the outer membrane, OprF assumes dual conformations and is involved in solute transport, as well as cell envelope integrity. Here, we review the current literature on OprF inP. aeruginosa, discussing how the structure and function of the cell-associated and matrix-associated protein may affect biofilm formation and pathogenesis in order to inform future research on this understudied matrix protein.

scholarly journals Targeting Fibronectin To Disrupt In Vivo Candida albicans Biofilms

2016 ◽  
Vol 60 (5) ◽  
pp. 3152-3155 ◽  
Author(s):  
Jeniel E. Nett ◽  
Jonathan Cabezas-Olcoz ◽  
Karen Marchillo ◽  
Deane F. Mosher ◽  
David R. Andes
Keyword(s):  
Candida Albicans ◽  
Biofilm Formation ◽  
Drug Targets ◽  
Venous Catheter ◽  
Surface Adhesion ◽  
Inhibitory Protein ◽  
Content Type ◽  
Novel Target

ABSTRACTNew drug targets are of great interest for the treatment of fungal biofilms, which are routinely resistant to antifungal therapies. We theorized that the interaction ofCandida albicanswith matricellular host proteins would provide a novel target. Here, we show that an inhibitory protein (FUD) targetingCandida-fibronectin interactions disrupts biofilm formationin vitroandin vivoin a rat venous catheter model. The peptide appears to act by blocking the surface adhesion ofCandida, halting biofilm formation.

scholarly journals The Histidine Kinase BinK Is a Negative Regulator of Biofilm Formation and Squid Colonization

2016 ◽  
Vol 198 (19) ◽  
pp. 2596-2607 ◽  
Author(s):  
John F. Brooks ◽  
Mark J. Mandel
Keyword(s):  
Histidine Kinase ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Negative Regulator ◽  
Epithelial Tissue ◽  
Temperature Modulation ◽  
Content Type ◽  
Animal Hosts ◽  
Biofilm Development

ABSTRACTBacterial colonization of animal epithelial tissue is a dynamic process that relies on precise molecular communication. Colonization ofEuprymna scolopesbobtail squid byVibrio fischeribacteria requires bacterial aggregation in host mucus as the symbiont transitions from a planktonic lifestyle in seawater to a biofilm-associated state in the host. We have identified a gene,binK(biofilm inhibitor kinase; VF_A0360), which encodes an orphan hybrid histidine kinase that negatively regulates theV. fischerisymbiotic biofilm (Syp)in vivoandin vitro. We identifiedbinKmutants as exhibiting a colonization advantage in a global genetic screen, a phenotype that we confirmed in controlled competition experiments. Bacterial biofilm aggregates in the host are larger in strains lacking BinK, whereas overexpression of BinK suppresses biofilm formation and squid colonization. Signaling through BinK is required for temperature modulation of biofilm formation at 28°C. Furthermore, we present evidence that BinK acts upstream of SypG, the σ54-dependent transcriptional regulator of thesypbiofilm locus. The BinK effects are dependent on intact signaling in the RscS-Syp biofilm pathway. Therefore, we propose that BinK antagonizes the signal from RscS and serves as an integral component inV. fischeribiofilm regulation.IMPORTANCEBacterial lifestyle transitions underlie the colonization of animal hosts from environmental reservoirs. Formation of matrix-enclosed, surface-associated aggregates (biofilms) is common in beneficial and pathogenic associations, but investigating the genetic basis of biofilm development in live animal hosts remains a significant challenge. Using the bobtail squid light organ as a model, we analyzed putative colonization factors and identified a histidine kinase that negatively regulates biofilm formation at the host interface. This work reveals a novelin vivobiofilm regulator that influences the transition of bacteria from their planktonic state in seawater to tight aggregates of cells in the host. The study enriches our understanding of biofilm regulation and beneficial colonization by an animal's microbiome.

scholarly journals Tissue Plasminogen Activator Coating on Implant Surfaces Reduces Staphylococcus aureus Biofilm Formation

2015 ◽  
Vol 82 (1) ◽  
pp. 394-401 ◽  
Author(s):  
Jakub Kwiecinski ◽  
Manli Na ◽  
Anders Jarneborn ◽  
Gunnar Jacobsson ◽  
Marijke Peetermans ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Medical Devices ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Content Type ◽  
Tissue Plasminogen

ABSTRACTStaphylococcus aureusbiofilm infections of indwelling medical devices are a major medical challenge because of their high prevalence and antibiotic resistance. As fibrin plays an important role inS. aureusbiofilm formation, we hypothesize that coating of the implant surface with fibrinolytic agents can be used as a new method of antibiofilm prophylaxis. The effect of tissue plasminogen activator (tPA) coating onS. aureusbiofilm formation was tested within vitromicroplate biofilm assays and anin vivomouse model of biofilm infection. tPA coating efficiently inhibited biofilm formation by variousS. aureusstrains. The effect was dependent on plasminogen activation by tPA, leading to subsequent local fibrin cleavage. A tPA coating on implant surfaces prevented both early adhesion and later biomass accumulation. Furthermore, tPA coating increased the susceptibility of biofilm infections to antibiotics.In vivo, significantly fewer bacteria were detected on the surfaces of implants coated with tPA than on control implants from mice treated with cloxacillin. Fibrinolytic coatings (e.g., with tPA) reduceS. aureusbiofilm formation bothin vitroandin vivo, suggesting a novel way to prevent bacterial biofilm infections of indwelling medical devices.

scholarly journals Accumulation-Associated Protein Enhances Staphylococcus epidermidis Biofilm Formation under Dynamic Conditions and Is Required for Infection in a Rat Catheter Model

2014 ◽  
Vol 83 (1) ◽  
pp. 214-226 ◽  
Author(s):  
Carolyn R. Schaeffer ◽  
Keith M. Woods ◽  
G. Matt Longo ◽  
Megan R. Kiedrowski ◽  
Alexandra E. Paharik ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Host Cells ◽  
Content Type ◽  
Microtiter Plates ◽  
Allelic Replacement ◽  
Abiotic Surfaces ◽  
Cell Accumulation ◽  
Accumulation Associated Protein

Biofilm formation is the primary virulence factor ofStaphylococcus epidermidis.S. epidermidisbiofilms preferentially form on abiotic surfaces and may contain multiple matrix components, including proteins such as accumulation-associated protein (Aap). Following proteolytic cleavage of the A domain, which has been shown to enhance binding to host cells, B domain homotypic interactions support cell accumulation and biofilm formation. To further define the contribution of Aap to biofilm formation and infection, we constructed anaapallelic replacement mutant and anicaADBC aapdouble mutant. When subjected to fluid shear, strains deficient in Aap production produced significantly less biofilm than Aap-positive strains. To examine thein vivorelevance of our findings, we modified our previously described rat jugular catheter model and validated the importance of immunosuppression and the presence of a foreign body to the establishment of infection. The use of our allelic replacement mutants in the model revealed a significant decrease in bacterial recovery from the catheter and the blood in the absence of Aap, regardless of the production of polysaccharide intercellular adhesin (PIA), a well-characterized, robust matrix molecule. Complementation of theaapmutant with full-length Aap (containing the A domain), but not the B domain alone, increased initial attachment to microtiter plates, as did intransexpression of the A domain in adhesion-deficientStaphylococcus carnosus. These results demonstrate Aap contributes toS. epidermidisinfection, which may in part be due to A domain-mediated attachment to abiotic surfaces.

scholarly journals Neisseria meningitidis Polynucleotide Phosphorylase Affects Aggregation, Adhesion, and Virulence

2016 ◽  
Vol 84 (5) ◽  
pp. 1501-1513 ◽  
Author(s):  
Jakob Engman ◽  
Aurel Negrea ◽  
Sara Sigurlásdóttir ◽  
Miriam Geörg ◽  
Jens Eriksson ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Posttranslational Modifications ◽  
Human Cells ◽  
Bacterial Attachment ◽  
Polynucleotide Phosphorylase ◽  
Gene Encoding ◽  
Content Type ◽  
Type Iv ◽  
Transcriptional Changes

Neisseria meningitidisautoaggregation is an important step during attachment to human cells. Aggregation is mediated by type IV pili and can be modulated by accessory pilus proteins, such as PilX, and posttranslational modifications of the major pilus subunit PilE. The mechanisms underlying the regulation of aggregation remain poorly characterized. Polynucleotide phosphorylase (PNPase) is a 3′–5′ exonuclease that is involved in RNA turnover and the regulation of small RNAs. In this study, we biochemically confirm that NMC0710 is theN. meningitidisPNPase, and we characterize its role inN. meningitidispathogenesis. We show that deletion of the gene encoding PNPase leads to hyperaggregation and increased adhesion to epithelial cells. The aggregation induced was found to be dependent on pili and to be mediated by excessive pilus bundling. PNPase expression was induced following bacterial attachment to human cells. Deletion of PNPase led to global transcriptional changes and the differential regulation of 469 genes. We also demonstrate that PNPase is required for full virulence in anin vivomodel ofN. meningitidisinfection. The present study shows that PNPase negatively affects aggregation, adhesion, and virulence inN. meningitidis.

scholarly journals Production of Staphylococcal Complement Inhibitor (SCIN) and Other Immune Modulators during the Early Stages ofStaphylococcus aureusBiofilm Formation in a Mammalian Cell Culture Medium

2018 ◽  
Vol 86 (8) ◽  
Author(s):  
Andi R. Sultan ◽  
Jasper W. Swierstra ◽  
Nicole A. Lemmens-den Toom ◽  
Susan V. Snijders ◽  
Silvie Hansenová Maňásková ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Innate Immune ◽  
Formyl Peptide Receptor ◽  
Complement Inhibitor ◽  
Inhibitory Protein ◽  
Content Type ◽  
Immune Modulators ◽  
Early Stages

ABSTRACTImmune modulators are known to be produced by matured biofilms and during different stages of planktonic growth ofStaphylococcus aureus. Little is known about immune modulator production during the early stages of biofilm formation, thus raising the following question: how doesS. aureusprotect itself from the innate immune responses at these stages? Therefore, we determined the production of the following immune modulators: chemotaxis inhibitory protein of staphylococci (CHIPS); staphylococcal complement inhibitor (SCIN); formyl peptide receptor-like 1 inhibitor; gamma-hemolysin component B; leukocidins D, E, and S; staphylococcal superantigen-like proteins 1, 3, 5, and 9; and staphylococcal enterotoxin A. Production was determined duringin vitrobiofilm formation in Iscove's modified Dulbecco's medium at different time points using a competitive Luminex assay and mass spectrometry. Both methods demonstrated the production of the immune modulators SCIN and CHIPS during the early stages of biofilm formation. The green fluorescence protein promoter fusion technology confirmedscn(SCIN) and, to a lesser extent,chp(CHIPS) transcription during the early stages of biofilm formation. Furthermore, we found that SCIN could inhibit human complement activation induced by early biofilms, indicating thatS. aureusis able to modulate the innate immune system already during the early stages of biofilm formationin vitro. These results form a stepping stone toward elucidating the role of immune modulators in the establishment of biofilmsin vivoand present opportunities to develop preventive strategies.

scholarly journals EDTA Inhibits Biofilm Formation, Extracellular Vesicular Secretion, and Shedding of the Capsular Polysaccharide Glucuronoxylomannan by Cryptococcus neoformans

2012 ◽  
Vol 78 (22) ◽  
pp. 7977-7984 ◽  
Author(s):  
Emma J. Robertson ◽  
Julie M. Wolf ◽  
Arturo Casadevall
Keyword(s):  
Cryptococcus Neoformans ◽  
Biofilm Formation ◽  
Capsular Polysaccharide ◽  
Inhibitory Effect ◽  
Antifungal Drugs ◽  
Biofilm Growth ◽  
Content Type ◽  
Sublethal Concentrations ◽  
Vesicular Secretion

ABSTRACTThe fungal pathogenCryptococcus neoformanscan grow as a biofilm on a range of synthetic and prosthetic materials. Cryptococcal biofilm formation can complicate the placement of shunts used to relieve increased intracranial pressure in cryptococcal meningitis and can serve as a nidus for chronic infection. Biofilms are generally advantageous to pathogensin vivo, as they can confer resistance to antimicrobial compounds, including fluconazole and voriconazole in the case ofC. neoformans. EDTA can inhibit biofilm formation by several microbes and enhances the susceptibility of biofilms to antifungal drugs. In this study, we evaluated the effect of sublethal concentrations of EDTA on the growth of cryptococcal biofilms. EDTA inhibited biofilm growth byC. neoformans, and the inhibition could be reversed by the addition of magnesium or calcium, implying that the inhibitory effect was by divalent cation starvation. EDTA also reduced the amount of the capsular polysaccharide glucuronoxylomannan shed into the biofilm matrix and decreased vesicular secretion from the cell, thus providing a potential mechanism for the inhibitory effect of this cation-chelating compound. Our data imply that the growth ofC. neoformansbiofilms requires the presence of divalent metals in the growth medium and suggest that cations are required for the export of materials needed for biofilm formation, possibly including extracellular vesicles.

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