scholarly journals Spatial correlations and distribution of competence gene expression in biofilms of Streptococcus mutans

2020 ◽  
Author(s):  
Ivan P. Ishkov ◽  
Justin R. Kaspar ◽  
Stephen J. Hagen
Keyword(s):  
Streptococcus Mutans ◽  
Spatial Clustering ◽  
Environmental Cues ◽  
Spatial Correlations ◽  
Oral Biofilm ◽  
Genetic Competence ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Signaling Peptides ◽  
And Oxidative Stress

ABSTRACTStreptococcus mutans is an important pathogen in the human oral biofilm. It expresses virulent behaviors that are linked to its genetic competence regulon, which is controlled by comX. Expression of comX is modulated by two diffusible signaling peptides, denoted CSP and XIP, and by other environmental cues such as pH and oxidative stress. The sensitivity of S. mutans competence to environmental inputs that may vary on microscopic length scales raises the question of whether the biofilm environment causes spatial clustering of S. mutans virulence behaviors, by creating microniches where competence and related phenotypes are concentrated. We have used two-photon microscopy to characterize the spatial distribution of comX expression among individual S. mutans cells in biofilms. By analyzing correlations in comX activity, we test for spatial clustering that may suggest localized, competence microenvironments. Our data indicate that both competence-signaling peptides diffuse efficiently through the biofilm. CSP triggers a Poisson-like, spatially random, comX response from a subpopulation of cells that is homogeneously dispersed. XIP elicits a population-wide response. Our data indicate that competence microenvironments if they exist are small enough that the phenotypes of individual cells are not clustered or correlated to any greater extent than occurs in planktonic cultures.

scholarly journals Spatial Correlations and Distribution of Competence Gene Expression in Biofilms of Streptococcus mutans

2021 ◽  
Vol 11 ◽  
Author(s):  
Ivan P. Ishkov ◽  
Justin R. Kaspar ◽  
Stephen J. Hagen
Keyword(s):  
Streptococcus Mutans ◽  
Spatial Clustering ◽  
Environmental Cues ◽  
Spatial Correlations ◽  
Oral Biofilm ◽  
Genetic Competence ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Signaling Peptides ◽  
And Oxidative Stress

Streptococcus mutans is an important pathogen in the human oral biofilm. It expresses virulent behaviors that are linked to its genetic competence regulon, which is controlled by comX. Expression of comX is modulated by two diffusible signaling peptides, denoted CSP and XIP, and by other environmental cues such as pH and oxidative stress. The sensitivity of S. mutans competence to environmental inputs that may vary on microscopic length scales raises the question of whether the biofilm environment creates microniches where competence and related phenotypes are concentrated, leading to spatial clustering of S. mutans virulence behaviors. We have used two-photon microscopy to characterize the spatial distribution of comX expression among individual S. mutans cells in biofilms. By analyzing correlations in comX activity, we test for spatial clustering that may suggest localized competence microenvironments. Our data indicate that both competence-signaling peptides diffuse efficiently through the biofilm. XIP elicits a population-wide response. CSP triggers a Poisson-like, spatially random comX response from a subpopulation of cells that is homogeneously dispersed. Our data indicate that competence microenvironments if they exist are small enough that the phenotypes of individual cells are not clustered or correlated to any greater extent than occurs in planktonic cultures.

scholarly journals Oxidative Stressors Modify the Response of Streptococcus mutans to Its Competence Signal Peptides

2017 ◽  
Vol 83 (22) ◽  
Author(s):  
Matthew De Furio ◽  
Sang Joon Ahn ◽  
Robert A. Burne ◽  
Stephen J. Hagen
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Dental Caries ◽  
Signaling Pathway ◽  
Streptococcus Mutans ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Oral Biofilm ◽  
Genetic Competence ◽  
Content Type

ABSTRACTThe dental caries pathogenStreptococcus mutansis continually exposed to several types of stress in the oral biofilm environment. Oxidative stress generated by reactive oxygen species has a major impact on the establishment, persistence, and virulence ofS. mutans. Here, we combined fluorescent reporter-promoter fusions with single-cell imaging to study the effects of reactive oxygen species on activation of genetic competence inS. mutans. Exposure to paraquat, which generates superoxide anion, produced a qualitatively different effect on activation of expression of the gene for the master competence regulator, ComX, than did treatment with hydrogen peroxide (H2O2), which can yield hydroxyl radical. Paraquat suppressed peptide-mediated induction ofcomXin a progressive and cumulative fashion, whereas the response to H2O2displayed a strong threshold behavior. Low concentrations of H2O2had little effect on induction ofcomXor the bacteriocin genecipB, but expression of these genes declined sharply if extracellular H2O2exceeded a threshold concentration. These effects were not due to decreased reporter gene fluorescence. Two different threshold concentrations were observed in the response to H2O2, depending on the gene promoter that was analyzed and the pathway by which the competence regulon was stimulated. The results show that paraquat and H2O2affect theS. mutanscompetence signaling pathway differently, and that some portions of the competence signaling pathway are more sensitive to oxidative stress than others.IMPORTANCEStreptococcus mutansinhabits the oral biofilm, where it plays an important role in the development of dental caries. Environmental stresses such as oxidative stress influence the growth ofS. mutansand its important virulence-associated behaviors, such as genetic competence.S. mutanscompetence development is a complex behavior that involves two different signaling peptides and can exhibit cell-to-cell heterogeneity. Although oxidative stress is known to influenceS. mutanscompetence, it is not understood how oxidative stress interacts with the peptide signaling or affects heterogeneity. In this study, we used fluorescent reporters to probe the effect of reactive oxygen species on competence signaling at the single-cell level. Our data show that different reactive oxygen species have different effects onS. mutanscompetence, and that some portions of the signaling pathway are more acutely sensitive to oxidative stress than others.

In vivo imaging of liver injury and regeneration by functional two-photon microscopy

2016 ◽  
Vol 54 (12) ◽  
pp. 1343-1404
Author(s):  
A Ghallab ◽  
R Reif ◽  
R Hassan ◽  
AS Seddek ◽  
JG Hengstler
Keyword(s):  
Liver Injury ◽  
In Vivo Imaging ◽  
Two Photon Microscopy ◽  
Two Photon

scholarly journals Adaptive Optical Two-Photon Microscopy for Surface-Profiled Living Biological Specimens

ACS Omega ◽  
2020 ◽  
Author(s):  
Kazushi Yamaguchi ◽  
Kohei Otomo ◽  
Yuichi Kozawa ◽  
Motosuke Tsutsumi ◽  
Tomoko Inose ◽  
...  
Keyword(s):  
Two Photon Microscopy ◽  
Two Photon

scholarly journals A Concise Review of Silver Diamine Fluoride on Oral Biofilm

2021 ◽  
Vol 11 (7) ◽  
pp. 3232
Author(s):  
Jingyang Zhang ◽  
Sofiya-Roksolana Got ◽  
Iris Xiaoxue Yin ◽  
Edward Chin-Man Lo ◽  
Chun-Hung Chu
Keyword(s):  
Clinical Study ◽  
Streptococcus Mutans ◽  
Bacterial Adhesion ◽  
Clinical Studies ◽  
Antibacterial Properties ◽  
Tooth Surface ◽  
Original Research ◽  
Laboratory Studies ◽  
Oral Biofilm ◽  
Silver Diamine Fluoride

Studies have shown that silver diamine fluoride (SDF) is an effective agent to arrest and prevent dental caries due to its mineralizing and antibacterial properties. While plenty of studies have investigated the mineralizing properties, there are few papers that have examined its antibacterial effect on oral biofilm. The objective of this study was to identify the effect of silver diamine fluoride on oral biofilm. Method: The keywords used were (silver diamine fluoride OR silver diammine fluoride OR SDF OR silver fluoride OR AgF AND biofilm OR plaque). Two reviewers screened the titles and abstracts and then retrieved the full text of the potentially eligible publications. Publications of original research investigating the effect of SDF on oral biofilm were selected for this review. Results: This review included 15 laboratory studies and six clinical studies among the 540 papers identified. The laboratory studies found that SDF could prevent bacterial adhesion to the tooth surface. SDF also inhibited the growth of cariogenic bacteria, including Streptococcus mutans, Lactobacillus acidophilus, Streptococcus sobrinus, Lactobacillus rhamnosus, Actinomyces naeslundii, and Enterococcus faecalis, thus contributing to its success in caries arrest. One clinical study reported a decrease in Streptococcus mutans and Lactobacillus sp. in arrested caries after SDF treatment, and another clinical study found that SDF inhibited the growth of periodontitis microbiota, including Porphyromonas gingivalis, Tannerella forsythia, and Prevotella intermedia/nigrescens. However, three clinical studies reported no significant change in the microbial diversity of the plaque on the tooth after SDF treatment. Moreover, one laboratory study and one clinical research study reported that SDF inhibited the growth of Candida albicans. Conclusion: Not many research studies have investigated the effects of SDF on oral biofilm, although SDF has been used as a caries-arresting agent with antibacterial properties. However, a few publications have reported that SDF prevented bacterial adhesion to the teeth, inhibited the growth of cariogenic and periodontal bacteria, and possessed antifungal properties.

scholarly journals Publisher Correction: Miniature two-photon microscopy for enlarged field-of-view, multi-plane and long-term brain imaging

2021 ◽  
Vol 18 (2) ◽  
pp. 220-220
Author(s):  
Weijian Zong ◽  
Runlong Wu ◽  
Shiyuan Chen ◽  
Junjie Wu ◽  
Hanbin Wang ◽  
...  
Keyword(s):  
Brain Imaging ◽  
Field Of View ◽  
Two Photon Microscopy ◽  
Two Photon

scholarly journals Publisher Correction: Ultrahigh-speed point scanning two-photon microscopy using high dynamic range silicon photomultipliers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vincent D. Ching-Roa ◽  
Eben M. Olson ◽  
Sherrif F. Ibrahim ◽  
Richard Torres ◽  
Michael G. Giacomelli
Keyword(s):  
Dynamic Range ◽  
High Dynamic Range ◽  
Silicon Photomultipliers ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
High Dynamic

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

scholarly journals Two-photon microscopy with simultaneous standard and extended depth of field using a tunable acoustic gradient-index lens

2009 ◽  
Vol 34 (11) ◽  
pp. 1684 ◽  
Author(s):  
Nicolas Olivier ◽  
Alexandre Mermillod-Blondin ◽  
Craig B. Arnold ◽  
Emmanuel Beaurepaire
Keyword(s):  
Depth Of Field ◽  
Gradient Index ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Gradient Index Lens ◽  
Extended Depth Of Field

scholarly journals Evaluation of Nanoparticle Penetration in the Tumor Spheroid Using Two-Photon Microscopy

Biomedicines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 10
Author(s):  
Feby Wijaya Pratiwi ◽  
Chien-Chung Peng ◽  
Si-Han Wu ◽  
Chiung Wen Kuo ◽  
Chung-Yuan Mou ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Solid Tumors ◽  
Physicochemical Parameters ◽  
Mesoporous Silica Nanoparticles ◽  
Model System ◽  
Tumor Spheroid ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Tumor Region ◽  
Penetration Behavior

Mesoporous silica nanoparticles (MSNs) have emerged as a prominent nanomedicine platform, especially for tumor-related nanocarrier systems. However, there is increasing concern about the ability of nanoparticles (NPs) to penetrate solid tumors, resulting in compromised antitumor efficacy. Because the physicochemical properties of NPs play a significant role in their penetration and accumulation in solid tumors, it is essential to systematically study their relationship in a model system. Here, we report a multihierarchical assessment of the accumulation and penetration of fluorescence-labeled MSNs with nine different physicochemical properties in tumor spheroids using two-photon microscopy. Our results indicated that individual physicochemical parameters separately could not define the MSNs’ ability to accumulate in a deeper tumor region; their features are entangled. We observed that the MSNs’ stability determined their success in reaching the hypoxia region. Moreover, the change in the MSNs’ penetration behavior postprotein crowning was associated with both the original properties of NPs and proteins on their surfaces.

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