scholarly journals Inactivation of Streptococcusgordonii SspAB Alters Expression of Multiple Adhesin Genes

2005 ◽  
Vol 73 (6) ◽  
pp. 3351-3357 ◽  
Author(s):  
Yongshu Zhang ◽  
Yu Lei ◽  
Angela Nobbs ◽  
Ali Khammanivong ◽  
Mark C. Herzberg
Keyword(s):  
Mutant Strain ◽  
Biofilm Formation ◽  
Oral Bacteria ◽  
Wild Type ◽  
Planktonic Cells ◽  
Initial Biofilm ◽  
Sessile Cells ◽  
Specific Mrna

ABSTRACT SspA and SspB (antigen I/II family proteins) can bind Streptococcus gordonii to other oral bacteria and also to salivary agglutinin glycoprotein, a constituent of the salivary film or pellicle that coats the tooth. To learn if SspA and SspB are essential for adhesion and initial biofilm formation on teeth, S. gordonii DL1 was incubated with saliva-coated hydroxyapatite (sHA) for 2 h in Todd-Hewitt broth with 20% saliva to develop initial biofilms. Sessile cells attached to sHA, surrounding planktonic cells, and free-growing cells were recovered separately. Free-growing cells expressed more sspA-specific mRNA and sspB-specific mRNA than sessile cells. Free-growing cells expressed the same levels of sspA and sspB as planktonic cells. Surprisingly, an SspA− SspB− mutant strain showed 2.2-fold greater biofilm formation on sHA than wild-type S. gordonii DL1. To explain this observation, we tested the hypothesis that inactivation of sspA and sspB genes altered the expression of other adhesin genes during initial biofilm formation in vitro. When compared to wild-type cells, expression of scaA and abpB was significantly up-regulated in the SspA− SspB− strain in sessile, planktonic, and free-growing cells. Consistent with this finding, ScaA antigen was also overexpressed in planktonic and free-growing SspA− SspB− cells compared to the wild type. SspA/B adhesins, therefore, were strongly suggested to be involved in the regulation of multiple adhesin genes.

Role of the luxS Gene in Initial Biofilm Formation by Streptococcus mutans

2015 ◽  
Vol 25 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Zhiyan He ◽  
Jingping Liang ◽  
Zisheng Tang ◽  
Rui Ma ◽  
Huasong Peng ◽  
...  
Keyword(s):  
Streptococcus Mutans ◽  
Mutant Strain ◽  
Biofilm Formation ◽  
Type Strain ◽  
Laser Scanning ◽  
Wild Type Strain ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wild Type ◽  
Initial Biofilm

Quorum sensing (QS) is a process by which bacteria communicate with each other by secreting chemical signals called autoinducers (AIs). Among Gram-negative and Gram-positive bacteria, AI-2 synthesized by the LuxS enzyme is widespread. The aim of this study was to evaluate the effect of QS <i>luxS</i> gene on initial biofilm formation by <i>Streptococcus mutans</i>. The bacterial cell surface properties, including cell hydrophobicity (bacterial adherence to hydrocarbons) and aggregation, which are important for initial adherence during biofilm development, were investigated. The biofilm adhesion assay was evaluated by the MTT method. The structures of the 5-hour biofilms were observed by using confocal laser scanning microscopy, and QS-related gene expressions were investigated by real-time PCR. The <i>luxS</i> mutant strain exhibited higher biofilm adherence and aggregation, but lower hydrophobicity than the wild-type strain. The confocal laser scanning microscopy images revealed that the wild-type strain tended to form smaller aggregates with uniform distribution, whereas the <i>luxS</i> mutant strain aggregated into distinct clusters easily discernible in the generated biofilm. Most of the genes examined were downregulated in the biofilms formed by the <i>luxS</i> mutant strain, except the <i>gtfB </i>gene. QS <i>luxS</i> gene can affect the initial biofilm formation by <i>S. mutans.</i>

scholarly journals Influence of Culture Media on Biofilm Formation byCandidaSpecies and Response of Sessile Cells to Antifungals and Oxidative Stress

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Isela Serrano-Fujarte ◽  
Everardo López-Romero ◽  
Georgina Elena Reyna-López ◽  
Ma. Alejandrina Martínez-Gámez ◽  
Arturo Vega-González ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Culture Media ◽  
Planktonic Cells ◽  
Human Immune System ◽  
Xtt Assay ◽  
Nutritional Conditions ◽  
Complex Process ◽  
Sessile Cells

The aims of the study were to evaluate the influence of culture media on biofilm formation byC. albicans, C. glabrata, C. krusei,andC. parapsilosisand to investigate the responses of sessile cells to antifungals and reactive oxygen species (ROS) as compared to planktonic cells. For biofilm formation, theCandidaspecies were grown at different periods of time in YP or YNB media supplemented or not with 0.2 or 2% glucose. Sessile and planktonic cells were exposed to increasing concentrations of antifungals, H2O2, menadione or silver nanoparticles (AgNPs). Biofilms were observed by scanning electron microscopy (SEM) and quantified by the XTT assay.C. albicansformed biofilms preferentially in YPD containing 2% glucose (YPD/2%),C. glabratain glucose-free YNB or supplemented with 0.2% glucose (YNB/0.2%), whileC. kruseiandC. parapsilosispreferred YP, YPD/0.2%, and YPD/2%. Interestingly, onlyC. albicansproduced an exopolymeric matrix. This is the first report dealing with thein vitroeffect of the culture medium and glucose on the formation of biofilms in fourCandidaspecies as well as the resistance of sessile cells to antifungals, AgNPs, and ROS. Our results suggest that candidiasisin vivois a multifactorial and complex process where the nutritional conditions, the human immune system, and the adaptability of the pathogen should be considered altogether to provide an effective treatment of the patient.

scholarly journals An AraC-Type Transcriptional Regulator Encoded on the Enterococcus faecalis Pathogenicity Island Contributes to Pathogenesis and Intracellular Macrophage Survival

2008 ◽  
Vol 76 (12) ◽  
pp. 5668-5676 ◽  
Author(s):  
Phillip S. Coburn ◽  
Arto S. Baghdayan ◽  
GT Dolan ◽  
Nathan Shankar
Keyword(s):  
Enterococcus Faecalis ◽  
Mutant Strain ◽  
Biofilm Formation ◽  
Transcriptional Regulator ◽  
Pathogenicity Island ◽  
Nucleotide Sequence Analysis ◽  
Infection Model ◽  
Wild Type ◽  
Altered Expression

ABSTRACT A gene encoding a putative AraC-type transcriptional regulator was identified on the 153-kb pathogenicity island (PAI) found among virulent Enterococcus faecalis strains. In an effort to understand the function of this regulator, designated PerA (for pathogenicity island-encoded regulator), we first examined the expression of the perA gene in the original PAI strain MMH594 and in an unrelated clinical isolate E99 by reverse transcription-PCR. Interestingly, expression analysis revealed no detectable perA transcript in MMH594, whereas a transcript was observed in strain E99. Nucleotide sequence analysis revealed that this altered expression between the two strains was attributable to the differential location of an IS1191 element within the putative promoter region upstream of the perA gene. In order to determine the role of this putative regulator in E. faecalis pathogenesis, a perA-deficient mutant was created in strain E99, and the wild-type and mutant pair were compared for phenotypic differences. In in vitro biofilm assays, the mutant strain showed a significantly higher level of growth medium-specific biofilm formation compared to the wild type. However, in a murine intraperitoneal infection model, the mutant strain was significantly less pathogenic. The mutant was also attenuated for survival within macrophages in vitro. These findings highlight the importance of PerA as a regulator of biofilm formation and survival within macrophages and is likely a regulator controlling determinants important to pathogenesis.

scholarly journals In VitroAnalyses of the Effects of Heparin and Parabens on Candida albicans Biofilms and Planktonic Cells

2011 ◽  
Vol 56 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Marisa H. Miceli ◽  
Stella M. Bernardo ◽  
T. S. Neil Ku ◽  
Carla Walraven ◽  
Samuel A. Lee
Keyword(s):  
Candida Albicans ◽  
Metabolic Activity ◽  
Biofilm Formation ◽  
High Dose ◽  
Dependent Manner ◽  
Planktonic Cells ◽  
Content Type ◽  
Heparin Sodium ◽  
The Individual

ABSTRACTInfections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin onCandida albicansbiofilms and planktonic cells have not been previously studied. Therefore, we sought to determine thein vitroeffect of a heparin sodium preparation (HP) on biofilms and planktonic cells ofC. albicans. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformedC. albicansbiofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (P< 0.0001). Pure-H, MP, and PP each inhibitedC. albicansbiofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H havein vitroantifungal activity againstC. albicansmature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention ofC. albicansbiofilms is warranted.

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 Anaerobic Conditions Induce Expression of Polysaccharide Intercellular Adhesin in Staphylococcus aureus and Staphylococcus epidermidis

2001 ◽  
Vol 69 (6) ◽  
pp. 4079-4085 ◽  
Author(s):  
Sarah E. Cramton ◽  
Martina Ulrich ◽  
Friedrich Götz ◽  
Gerd Döring
Keyword(s):  
Staphylococcus Aureus ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Extracellular Polysaccharide ◽  
Growth Conditions ◽  
Anaerobic Conditions ◽  
Anaerobic Environment ◽  
Specific Mrna

ABSTRACT Products of the intercellular adhesion (ica) operon in Staphylococcus aureus and Staphylococcus epidermidis synthesize a linear β-1,6-linked glucosaminylglycan. This extracellular polysaccharide mediates bacterial cell-cell adhesion and is required for biofilm formation, which is thought to increase the virulence of both pathogens in association with prosthetic biomedical implants. The environmental signal(s) that triggers ica gene product and polysaccharide expression is unknown. Here we demonstrate that anaerobic in vitro growth conditions lead to increased polysaccharide expression in both S. aureus and S. epidermidis, although the regulation is less stringent inS. epidermidis. Anaerobiosis also dramatically stimulates ica-specific mRNA expression inica- and polysaccharide-positive strains of both S. aureus and S. epidermidis.These data suggest a mechanism whereby ica gene expression and polysaccharide production may act as a virulence factor in an anaerobic environment in vivo.

scholarly journals Effect of Nitroxides on Swarming Motility and Biofilm Formation, Multicellular Behaviors in Pseudomonas aeruginosa

2013 ◽  
Vol 57 (10) ◽  
pp. 4877-4881 ◽  
Author(s):  
César de la Fuente-Núñez ◽  
Fany Reffuveille ◽  
Kathryn E. Fairfull-Smith ◽  
Robert E. W. Hancock
Keyword(s):  
Nitric Oxide ◽  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Wild Type ◽  
Planktonic Cells ◽  
Swarming Motility ◽  
Content Type ◽  
Exogenous Addition ◽  
Biofilm Dispersion ◽  
Dispersal Activity

ABSTRACTThe ability of nitric oxide (NO) to induce biofilm dispersion has been well established. Here, we investigated the effect of nitroxides (sterically hindered nitric oxide analogues) on biofilm formation and swarming motility inPseudomonas aeruginosa. A transposon mutant unable to produce nitric oxide endogenously (nirS) was deficient in swarming motility relative to the wild type and the complemented strain. Moreover, expression of thenirSgene was upregulated by 9.65-fold in wild-type swarming cells compared to planktonic cells. Wild-type swarming levels were substantially restored upon the exogenous addition of nitroxide containing compounds, a finding consistent with the hypothesis that NO is necessary for swarming motility. Here, we showed that nitroxides not only mimicked the dispersal activity of NO but also prevented biofilms from forming in flow cell chambers. In addition, anirStransposon mutant was deficient in biofilm formation relative to the wild type and the complemented strain, thus implicating NO in the formation of biofilms. Intriguingly, despite its stand-alone action in inhibiting biofilm formation and promoting dispersal, a nitroxide partially restored the ability of anirSmutant to form biofilms.

Inhibitory activity of isoniazid and ethionamide against Cryptococcus biofilms

2015 ◽  
Vol 61 (11) ◽  
pp. 827-836 ◽  
Author(s):  
Rossana de Aguiar Cordeiro ◽  
Rosana Serpa ◽  
Francisca Jakelyne de Farias Marques ◽  
Charlline Vládia Silva de Melo ◽  
Antonio José de Jesus Evangelista ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Biofilm Formation ◽  
Inhibitory Effect ◽  
Cell Membrane Permeability ◽  
Planktonic Cells ◽  
Fungal Cell ◽  
Antituberculosis Drugs ◽  
Opportunistic Mycoses ◽  
Cryptococcus Spp

In recent years, the search for drugs to treat systemic and opportunistic mycoses has attracted great interest from the scientific community. This study evaluated the in vitro inhibitory effect of the antituberculosis drugs isoniazid and ethionamide alone and combined with itraconazole and fluconazole against biofilms of Cryptococcus neoformans and Cryptococcus gattii. Antimicrobials were tested at defined concentrations after susceptibility assays with Cryptococcus planktonic cells. In addition, we investigated the synergistic interaction of antituberculosis drugs and azole derivatives against Cryptococcus planktonic cells, as well as the influence of isoniazid and ethionamide on ergosterol content and cell membrane permeability. Isoniazid and ethionamide inhibited both biofilm formation and viability of mature biofilms. Combinations formed by antituberculosis drugs and azoles proved synergic against both planktonic and sessile cells, showing an ability to reduce Cryptococcus biofilms by approximately 50%. Furthermore, isoniazid and ethionamide reduced the content of ergosterol in Cryptococcus spp. planktonic cells and destabilized or permeabilized the fungal cell membrane, leading to leakage of macromolecules. Owing to the paucity of drugs able to inhibit Cryptococcus biofilms, we believe that the results presented here might be of interest in the designing of new antifungal compounds.

scholarly journals The Role of a P1-Type ATPase from Pseudomonas fluorescens SBW25 in Copper Homeostasis and Plant Colonization

2007 ◽  
Vol 20 (5) ◽  
pp. 581-588 ◽  
Author(s):  
Xue-Xian Zhang ◽  
Paul B. Rainey
Keyword(s):  
Pseudomonas Fluorescens ◽  
Mutant Strain ◽  
Copper Ions ◽  
Biological Significance ◽  
Copper Homeostasis ◽  
Plant Colonization ◽  
Wild Type ◽  
Pseudomonas Fluorescens Sbw25 ◽  
Plant Surfaces

The genome of the plant-colonizing bacterium Pseudomonas fluorescens SBW25 possesses a putative copper-transporting P1-type ATPase (CueA) that is induced on the plant surfaces. Using a chromosomally-integrated cueA-'lacZ fusion, we show that transcription of cueA can be induced (in vitro) by ions of copper, silver, gold, and mercury. To investigate the biological significance of cueA, a nonpolar cueA deletion mutant (SBW25ΔcueA) was constructed. This mutant strain displayed a twofold reduction in its tolerance to copper compared with the wild-type strain; however, no change was observed in the sensitivity of the mutant strain to silver, gold, or mercury ions. To obtain insight into the ecological significance of cueA, the competitive ability of SBW25ΔcueA was determined relative to wild-type SBW25 in three environments (none contained added copper): minimal M9 medium, the root of sugar beet (Beta vulgaris), and the root of pea (Pisum sativum). Results showed that the fitness of SBW25ΔcueA was not different from the wild type in laboratory medium but was compromised in the two plant environments. Taken together, these data demonstrate a functional role for CueA in copper homeostasis and reveal an ecologically significant contribution to bacterial fitness in the plant rhizosphere. They also suggest that copper ions accumulate on plant surfaces.

scholarly journals Transposon Insertion in the purL Gene Induces Biofilm Depletion in Escherichia coli ATCC 25922

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 774
Author(s):  
Virginio Cepas ◽  
Victoria Ballén ◽  
Yaiza Gabasa ◽  
Miriam Ramírez ◽  
Yuly López ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
De Novo ◽  
Wild Type ◽  
Planktonic Cells ◽  
E Coli ◽  
Qrt Pcr ◽  
Transposon Insertion ◽  
De Novo Purine Biosynthesis

Current Escherichia coli antibiofilm treatments comprise a combination of antibiotics commonly used against planktonic cells, leading to treatment failure. A better understanding of the genes involved in biofilm formation could facilitate the development of efficient and specific new antibiofilm treatments. A total of 2578 E. coli mutants were generated by transposon insertion, of which 536 were analysed in this study. After sequencing, Tn263 mutant, classified as low biofilm-former (LF) compared to the wild-type (wt) strain (ATCC 25922), showed an interruption in the purL gene, involved in the de novo purine biosynthesis pathway. To elucidate the role of purL in biofilm formation, a knockout was generated showing reduced production of curli fibres, leading to an impaired biofilm formation. These conditions were restored by complementation of the strain or addition of exogenous inosine. Proteomic and transcriptional analyses were performed to characterise the differences caused by purL alterations. Thirteen proteins were altered compared to wt. The corresponding genes were analysed by qRT-PCR not only in the Tn263 and wt, but also in clinical strains with different biofilm activity. Overall, this study suggests that purL is essential for biofilm formation in E. coli and can be considered as a potential antibiofilm target.

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