scholarly journals Role of FAD-I in Fusobacterial Interspecies Interaction and Biofilm Formation

2020 ◽  
Vol 8 (1) ◽  
pp. 70 ◽  
Author(s):  
Bhumika Shokeen ◽  
Jane Park ◽  
Emily Duong ◽  
Sonam Rambhia ◽  
Manash Paul ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Fusobacterium Nucleatum ◽  
Interspecies Interaction ◽  
Wild Type ◽  
Oral Epithelial Cells ◽  
Small Proteins ◽  
Mutant Strains ◽  
Oral Epithelial ◽  
Wild Type Parent

RadD, a major adhesin of oral fusobacteria, is part of a four-gene operon encoding the small lipoprotein FAD-I and two currently uncharacterized small proteins encoded by the rapA and rapB genes. Previously, we described a role for FAD-I in the induction of human B-defensin 2 (hBD2) upon contact with oral epithelial cells. Here, we investigated potential roles for fad-I, rapA, and rapB in interspecies interaction and biofilm formation. Gene inactivation mutants were generated for each of these genes in the nucleatum and polymorphum subspecies of Fusobacterium nucleatum and characterized for their adherence to partner species, biofilm formation, and operon transcription. Binding to Streptococcus gordonii was increased in all mutant strains with Δfad-I having the most significant effect. This increased adherence was directly proportional to elevated radD transcript levels and resulted in significantly different architecture and height of the biofilms formed by Δfad-I and S. gordonii compared to the wild-type parent. In conclusion, FAD-I is important for fusobacterial interspecies interaction as its lack leads to increased production of the RadD adhesin suggesting a role of FAD-I in its regulation. This regulatory effect does not require the presence of functional RadD.

scholarly journals Mutagenic strategies against luxS gene affect the early stage of biofilm formation of Campylobacter jejuni

2021 ◽  
Author(s):  
Martin Tereň ◽  
Ekaterina Shagieva ◽  
Lucie Vondrakova ◽  
Jitka Viktorova ◽  
Viviana Svarcova ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Biofilm Formation ◽  
Early Stage ◽  
Wild Type ◽  
Genetic Determinants ◽  
Autoinducer 2 ◽  
Naturally Occurring ◽  
Mutant Strains ◽  
The Impact

Abstract Currently, it is clear that the luxS gene has an impact on the process of biofilm formation in Campylobacter jejuni. However, even within the species naturally occurring strains of Campylobacter lacking the luxS gene exist, which can form biofilms. In order to better understand the genetic determinants and the role of quorum sensing through the LuxS/AI-2 pathway in biofilm formation, a set of mutant/complemented strains of C. jejuni 81–176 were prepared. Additionally, the impact of the mutagenic strategy used against the luxS gene was investigated. Biofilm formation was affected by both the presence and absence of the luxS gene, and by the mutagenic strategy used. Analysis by CLSM showed that all mutant strains formed significantly less biofilm mass when compared to the wild-type. Interestingly, the deletion mutant (∆luxS) showed a larger decrease in biofilm mass than the substitution (∙luxS) and insertional inactivated (⸬luxS) mutants, even though all the mutant strains lost the ability to produce autoinducer-2 molecules. Moreover, the biofilm of the ∆luxS mutant lacked the characteristic microcolonies observed in all other strains. The complementation of all mutant strains resulted in restored ability to produce AI-2, to form a complex biofilm, and to develop microcolonies at the level of the wild-type.

scholarly journals TatD DNases Contribute to Biofilm Formation and Virulence in Trueperella pyogenes

2021 ◽  
Vol 12 ◽  
Author(s):  
Zehui Zhang ◽  
Yinfeng Liang ◽  
Lihui Yu ◽  
Menghan Chen ◽  
Yuru Guo ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Wild Type Strain ◽  
Divalent Cations ◽  
Bacterial Load ◽  
Economic Losses ◽  
Wild Type ◽  
Trueperella Pyogenes ◽  
Mutant Strains ◽  
Sequence Characteristics

TatD DNases are conserved proteins in a variety of organisms and are considered potential virulence factors in Plasmodium falciparum and Streptococcus pneumoniae. However, the function of TatD DNases has not yet been determined in Trueperella pyogenes, which causes various infections in animals and leads to economic losses. In this study, we describe the roles of TatD DNases in T. pyogenes (TpTatDs). A bioinformatics analysis was performed to investigate the sequence characteristics of TpTatDs, and then the ability of recombinant TatD proteins to hydrolyze DNA was determined in the presence of divalent cations. Moreover, we constructed tatD-deficient mutants. The biofilms formed by the wild-type and mutant strains were observed under a microscope. The mortality and bacterial load in the spleen of mice infected with the wild-type strain and tatD-deficient mutants were determined to obtain insights into the role of TatDs in the virulence of T. pyogenes. Two TatD DNases were identified in T. pyogenes. They were Mg2+-dependent DNases and exhibited DNA endonuclease activity. Compared with those formed by the parental strain, biofilms formed by mutants showed a significantly reduced thickness and biomass. Moreover, mutants produced a lower bacterial load in the spleen of mice and compromised virulence. Our data indicated that TatD DNases in T. pyogenes are involved in biofilm formation and required for virulence during infections.

scholarly journals The Exopolysaccharide of Xylella fastidiosa Is Essential for Biofilm Formation, Plant Virulence, and Vector Transmission

2013 ◽  
Vol 26 (9) ◽  
pp. 1044-1053 ◽  
Author(s):  
N. Killiny ◽  
R. Hernandez Martinez ◽  
C. Korsi Dumenyo ◽  
D. A. Cooksey ◽  
R. P. P. Almeida
Keyword(s):  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Xylella Fastidiosa ◽  
Growth Characteristics ◽  
Gas Chromatography Mass Spectrometry ◽  
Wild Type ◽  
Mutant Strains ◽  
Plant Movement

Exopolysaccharides (EPS) synthesized by plant-pathogenic bacteria are generally essential for virulence. The role of EPS produced by the vector-transmitted bacterium Xylella fastidiosa was investigated by knocking out two genes implicated in the EPS biosynthesis, gumD and gumH. Mutant strains were affected in growth characteristics in vitro, including adhesion to surfaces and biofilm formation. In addition, different assays were used to demonstrate that the mutant strains produced significantly less EPS compared with the wild type. Furthermore, gas chromatography–mass spectrometry showed that both mutant strains did not produce oligosaccharides. Biologically, the mutants were deficient in movement within plants, resulting in an avirulent phenotype. Additionally, mutant strains were affected in transmission by insects: they were very poorly transmitted by and retained within vectors. The gene expression profile indicated upregulation of genes implicated in cell-to-cell signaling and adhesins while downregulation in genes was required for within-plant movement in EPS-deficient strains. These results suggest an essential role for EPS in X. fastidiosa interactions with both plants and insects.

scholarly journals A cocoa (Theobroma cacao L.) extract impairs the growth, virulence properties, and inflammatory potential of Fusobacterium nucleatum and improves oral epithelial barrier function

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252029
Author(s):  
Amel Ben Lagha ◽  
Patricia Maquera Huacho ◽  
Daniel Grenier
Keyword(s):  
Epithelial Cells ◽  
Barrier Function ◽  
Theobroma Cacao ◽  
Biofilm Formation ◽  
Periodontal Diseases ◽  
Fusobacterium Nucleatum ◽  
Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
Oral Epithelial Cells ◽  
Oral Epithelial

Fusobacterium nucleatum is associated with many conditions and diseases, including periodontal diseases that affect tooth-supporting tissues. The aim of the present study was to investigate the effects of a cocoa extract (Theobroma cacao L.) on F. nucleatum with respect to growth, biofilm formation, adherence, and hydrogen sulfide (H2S) production. The anti-inflammatory properties and the effect on epithelial barrier function of the cocoa extract were also assessed. The cocoa extract, whose major phenolic compound is epicatechin, dose-dependently inhibited the growth, biofilm formation, adherence properties (basement membrane matrix, oral epithelial cells), and H2S production of F. nucleatum. It also decreased IL-6 and IL-8 production by F. nucleatum-stimulated oral epithelial cells and inhibited F. nucleatum-induced NF-κB activation in monocytes. Lastly, the cocoa extract enhanced the barrier function of an oral epithelial model by increasing the transepithelial electrical resistance. We provide evidence that the beneficial properties of an epicatechin-rich cocoa extract may be useful for preventing and/or treating periodontal diseases.

scholarly journals RND Efflux Systems Contribute to Resistance and Virulence of Aliarcobacter butzleri

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 823
Author(s):  
Cristiana Mateus ◽  
Ana Rita Nunes ◽  
Mónica Oleastro ◽  
Fernanda Domingues ◽  
Susana Ferreira
Keyword(s):  
Oxidative Stress ◽  
Human Serum ◽  
Ethidium Bromide ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Efflux Pumps ◽  
Bacterial Virulence ◽  
Relative Fitness ◽  
Mutant Strains

Aliarcobacter butzleri is an emergent enteropathogen that can be found in a range of environments. This bacterium presents a vast repertoire of efflux pumps, such as the ones belonging to the resistance nodulation cell division family, which may be associated with bacterial resistance, as well as virulence. Thus, this work aimed to evaluate the contribution of three RND efflux systems, AreABC, AreDEF and AreGHI, in the resistance and virulence of A. butzleri. Mutant strains were constructed by inactivation of the gene that encodes the inner membrane protein of these systems. The bacterial resistance profile of parental and mutant strains to several antimicrobials was assessed, as was the intracellular accumulation of the ethidium bromide dye. Regarding bacterial virulence, the role of these three efflux pumps on growth, strain fitness, motility, biofilm formation ability, survival in adverse conditions (oxidative stress and bile salts) and human serum and in vitro adhesion and invasion to Caco-2 cells was evaluated. We observed that the mutants from the three efflux pumps were more susceptible to several classes of antimicrobials than the parental strain and presented an increase in the accumulation of ethidium bromide, indicating a potential role of the efflux pumps in the extrusion of antimicrobials. The mutant strains had no bacterial growth defects; nonetheless, they presented a reduction in relative fitness. For the three mutants, an increase in the susceptibility to oxidative stress was observed, while only the mutant for AreGHI efflux pump showed a relevant role in bile stress survival. All the mutant strains showed an impairment in biofilm formation ability, were more susceptible to human serum and were less adherent to intestinal epithelial cells. Overall, the results support the contribution of the efflux pumps AreABC, AreDEF and AreGHI of A. butzleri to antimicrobial resistance, as well as to bacterial virulence.

scholarly journals Effect of a Berry Polyphenolic Fraction on Biofilm Formation, Adherence Properties and Gene Expression of Streptococcus mutans and Its Biocompatibility with Oral Epithelial Cells

Antibiotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 46
Author(s):  
Mariem Souissi ◽  
Amel Ben Lagha ◽  
Kamel Chaieb ◽  
Daniel Grenier
Keyword(s):  
Epithelial Cells ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Cell Model ◽  
Pcr Analysis ◽  
Adhesion Properties ◽  
Oral Epithelial Cells ◽  
Polymerase Chain ◽  
Oral Epithelial ◽  
Wild Blueberry

The ability of Streptococcus mutans to adhere to oral surfaces and form biofilm is a key step in the tooth decay process. The aim of this study was to investigate a berry (wild blueberry, cranberry, and strawberry) polyphenolic fraction, commercialized as Orophenol®, for its antibacterial, anti-biofilm, and anti-adhesion properties on S. mutans. Moreover, the biocompatibility of the fraction with human oral epithelial cells was assessed. Phenolic acids, flavonoids (flavonols, anthocyanins, flavan-3-ols), and procyanidins made up 10.71%, 19.76%, and 5.29% of the berry polyphenolic fraction, respectively, as determined by chromatography and mass spectrometry. The berry polyphenolic preparation dose-dependently inhibited S. mutans biofilm formation while not reducing bacterial growth. At concentrations ranging from 250 to 1000 µg/mL, the fraction inhibited the adhesion of S. mutans to both saliva-coated hydroxyapatite and saliva-coated nickel–chrome alloy. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed that incubating S. mutans with the berry polyphenolic fraction was associated with a reduced expression of luxS gene, which regulates quorum sensing in S. mutans. The berry fraction did not show any significant cytotoxicity in an oral epithelial cell model. In conclusion, Orophenol®, which is a mixture of polyphenols from wild blueberry, cranberry and strawberry, possesses interesting anti-caries properties while being compatible with oral epithelial cells.

scholarly journals Pneumococcal Surface Protein C Contributes to Sepsis Caused by Streptococcus pneumoniae in Mice

2004 ◽  
Vol 72 (5) ◽  
pp. 3077-3080 ◽  
Author(s):  
Francesco Iannelli ◽  
Damiana Chiavolini ◽  
Susanna Ricci ◽  
Marco Rinaldo Oggioni ◽  
Gianni Pozzi
Keyword(s):  
Streptococcus Pneumoniae ◽  
Protein C ◽  
Lethal Dose ◽  
Surface Protein ◽  
Infection Model ◽  
Wild Type ◽  
Mutant Strains ◽  
Type 3

ABSTRACT The role of pneumococcal surface protein C (PspC; also called SpsA, CbpA, and Hic) in sepsis by Streptococcus pneumoniae was investigated in a murine infection model. The pspC gene was deleted in strains D39 (type 2) and A66 (type 3), and the mutants were tested by being injected intravenously into mice. The animals infected with the mutant strains showed a significant increase in survival, with the 50% lethal dose up to 250-fold higher than that for the wild type. Our findings indicate that PspC affords a decisive contribution to sepsis development.

scholarly journals Expression of Mycobacterium smegmatisPyrazinamidase in Mycobacterium tuberculosis Confers Hypersensitivity to Pyrazinamide and Related Amides

2000 ◽  
Vol 182 (19) ◽  
pp. 5479-5485 ◽  
Author(s):  
Helena I. M. Boshoff ◽  
Valerie Mizrahi
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Smegmatis ◽  
Intracellular Localization ◽  
Wild Type ◽  
Gene Encoding ◽  
Allelic Exchange ◽  
Mutant Strains ◽  
Established Role ◽  
Amidase Gene

ABSTRACT A pyrazinamidase (PZase)-deficient pncA mutant ofMycobacterium tuberculosis, constructed by allelic exchange, was used to investigate the effects of heterologous amidase gene expression on the susceptibility of this organism to pyrazinamide (PZA) and related amides. The mutant was highly resistant to PZA (MIC, >2,000 μg/ml), in accordance with the well-established role ofpncA in the PZA susceptibility of M. tuberculosis (A. Scorpio and Y. Zhang, Nat. Med. 2:662–667, 1996). Integration of the pzaA gene encoding the major PZase/nicotinamidase from Mycobacterium smegmatis (H. I. M. Boshoff and V. Mizrahi, J. Bacteriol. 180:5809–5814, 1998) or the M. tuberculosis pncA gene into the pncAmutant complemented its PZase/nicotinamidase defect. In bothpzaA- and pncA-complemented mutant strains, the PZase activity was detected exclusively in the cytoplasm, suggesting an intracellular localization for PzaA and PncA. ThepzaA-complemented strain was hypersensitive to PZA (MIC, ≤10 μg/ml) and nicotinamide (MIC, ≥20 μg/ml) and was also sensitive to benzamide (MIC, 20 μg/ml), unlike the wild-type andpncA-complemented mutant strains, which were highly resistant to this amide (MIC, >500 μg/ml). This finding was consistent with the observation that benzamide is hydrolyzed by PzaA but not by PncA. Overexpression of PzaA also conferred sensitivity to PZA, nicotinamide, and benzamide on M. smegmatis (MIC, 150 μg/ml in all cases) and rendered Escherichia colihypersensitive for growth at low pH.

scholarly journals Immune Tolerance in the Oral Mucosa

2021 ◽  
Vol 22 (22) ◽  
pp. 12149
Author(s):  
Hector F. Pelaez-Prestel ◽  
Jose L. Sanchez-Trincado ◽  
Esther M. Lafuente ◽  
Pedro A. Reche
Keyword(s):  
Epithelial Cells ◽  
Oral Mucosa ◽  
Immune Cells ◽  
Commensal Bacteria ◽  
First Line ◽  
Innate And Adaptive Immunity ◽  
Oral Epithelial Cells ◽  
A Site ◽  
Oral Epithelial

The oral mucosa is a site of intense immune activity, where a large variety of immune cells meet to provide a first line of defense against pathogenic organisms. Interestingly, the oral mucosa is exposed to a plethora of antigens from food and commensal bacteria that must be tolerated. The mechanisms that enable this tolerance are not yet fully defined. Many works have focused on active immune mechanisms involving dendritic and regulatory T cells. However, epithelial cells also make a major contribution to tolerance by influencing both innate and adaptive immunity. Therefore, the tolerogenic mechanisms concurring in the oral mucosa are intertwined. Here, we review them systematically, paying special attention to the role of oral epithelial cells.

LuxS modulates motility and secretion of extracellular protease in fish pathogen Vibrio harveyi

2021 ◽  
Author(s):  
yaqiu Zhang ◽  
Yiqing Deng ◽  
Juan Feng ◽  
Jianmei Hu ◽  
Haoxiang Chen ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Stationary Growth Phase ◽  
Extracellular Protease ◽  
Fish Pathogen ◽  
Wild Type ◽  
Stationary Growth ◽  
Qrt Pcr ◽  
Reverse Transcription Pcr ◽  
Luxs Mutant

In this study, an in-frame deletion of the luxS gene was constructed to reveal the role of LuxS in the physiology and virulence of V. harveyi. The statistical analysis showed no significant differences in the growth ability, biofilm formation, antibiotic susceptibility, virulence by intraperitoneal injection, and the ability of V. harveyi to colonize the spleen and liver of the pearl gentian grouper between the wild-type (WT) and the luxS mutant. However, the deletion of luxS decreased the secretion of extracellular protease, while increased the ability of swimming and swarming. Simultaneously, a luxS-deleted mutant showed overproduction of lateral flagella, and an intact luxS complemented the defect. Since motility is flagella dependent, 16 of V. harveyi flagella biogenesis related genes were selected for further analysis. Based on quantitative real-time reverse transcription-PCR (qRT-PCR), the expression levels of these genes, including the polar flagella genes flaB, flhA, flhF, flhB, flhF, fliS, and flrA and the lateral flagella genes flgA, flgB, fliE, fliF, lafA, lafK, and motY, were significantly up-regulated in the ΔluxS: pMMB207 (ΔluxS+) strain as compared with the V. harveyi 345: pMMB207 (WT+) and C-ΔluxS strains during the early, mid-exponential, and stationary growth phase.

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