In situ control of root–bacteria interactions using optical trapping in transparent soil

Bacterial attachment on root surfaces is an important step preceding the colonisation or internalisation and subsequent infection of plants by pathogens. Unfortunately, bacterial attachment is not well understood because the phenomenon is difficult to observe. Here we assessed whether this limitation could be overcome using optical trapping approaches. We have developed a system based on counter-propagating beams and studied its ability to guide Pectobacterium atrosepticum (Pba) cells to different root cell types within the interstices of transparent soils. Bacterial cells were successfully trapped and guided to root hair cells, epidermis cells, border cells and tissues damaged by laser ablation. Finally, we used the system to quantify the bacterial cell detachment rate of Pba cells on root surfaces following reversible attachment. Optical trapping techniques could greatly enhance our ability to deterministically characterise mechanisms linked to attachment and formation of biofilms in the rhizosphere.

Reducing Phenanthrene Contamination in Trifolium repens L. With Root-Associated Phenanthrene-Degrading Bacterium Diaphorobacter sp. Phe15

Some root-associated bacteria could degrade polycyclic aromatic hydrocarbons (PAHs) in contaminated soil; however, their dynamic distribution and performance on root surface and in inner plant tissues are still unclear. In this study, greenhouse container experiments were conducted by inoculating the phenanthrene-degrading bacterium Diaphorobacter sp. Phe15, which was isolated from root surfaces of healthy plants contaminated with PAHs, with the white clover (Trifolium repens L.) via root irrigation or seed soaking. The dynamic colonization, distribution, and performance of Phe15 in white clover were investigated. Strain Phe15 could efficiently degrade phenanthrene in shaking flasks and produce IAA and siderophore. After cultivation for 30, 40, and 50 days, it could colonize the root surface of white clover by forming aggregates and enter its inner tissues via root irrigation or seed soaking. The number of strain Phe15 colonized on the white clover root surfaces was the highest, reaching 6.03 Log CFU⋅g–1 FW, followed by that in the roots and the least in the shoots. Colonization of Phe15 significantly reduced the contents of phenanthrene in white clover; the contents of phenanthrene in Phe15-inoculated plants roots and shoots were reduced by 29.92–43.16 and 41.36–51.29%, respectively, compared with the Phe15-free treatment. The Phe15 colonization also significantly enhanced the phenanthrene removal from rhizosphere soil. The colonization and performance of strain Phe15 in white clove inoculated via root inoculation were better than seed soaking. This study provides the technical support and the resource of strains for reducing the plant PAH pollution in PAH-contaminated areas.

ANALYSIS OF BIOFILMS FOR STREPTOCOCCUS MUTANS FROM DENTAL ROOT SURFACES OF ADULT PATIENTS WITH ROOT CARIES

Background and objectives: Knowledge of the pathogenicity of the primary etiological factor of root caries, the microbial biofilm, might provide important information for the development of diagnosis and treatment strategies. This study assessed the numbers and revealed the proportion of Mutans streptococci , which is potential important cariogenic organisms, in biofilms collected from lesions at root surfaces with active caries lesions (ARC), inactive caries lesions, and sound root surfaces (SRS). Material and methods: Samples were cultured in MSB agar for Mutans streptococci counts, and brain-heart infusion agar for total viable anaerobic counts. After incubation, the number of colony-forming units (CFUs) was determined and compared between groups by the Mann-Whitney U test with a significance level set at 95%. The proportion of counts of Mutans streptococci in the total viable microorganisms was also analyzed by Chi-square test. 108 samples (36 from each surface) from 36 patients were cultured and analyzed. Results: The mean±SD for the counts of active root caries lesions was 7.47±9.89 10, significantly higher than that of inactive root caries lesions (2.5±0.97) and sound root surfaces (3.03±0.71). In conclusion, a trend towards higher counts was evident for ARC. In the ARC lesions among the dominant oral anaerobic bacteria, we could not identify streptococcal colonies (unspecified) in 11% while in IRC lesions it occurred in 47%, and SRS it occurred in 47%. In addition, in ARC the samples were ≥0.1-≥10 (CFU x10) ≥0.1-≥10 colonies of Streptococcus mutans. Conclusion: In conclusion, a trend towards higher counts was evident for ARC and for most samples, the proportion of Streptococcus mutans was low relative to the viable number of total viable anaerobic microorganisms. Peer Review History: Received: 5 September 2021; Revised: 10 October; Accepted: 24 October, Available online: 15 November 2021 Academic Editor: Ahmad Najib, Universitas Muslim Indonesia, Indones UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file: Reviewer's Comments: Average Peer review marks at initial stage: 6.0/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Dr. Rawaa Souhil Al-Kayali, Aleppo University, Syria, [email protected] Dr. Tamer Elhabibi, Suez Canal University, Egypt, [email protected] Similar Articles: ASSOCIATION BETWEEN THE STREPTOCOCCUS MUTANS BIOFILM FORMATION AND DENTAL CARIES EXPERIENCE AND ANTIBIOTICS RESISTANCE IN ADULT FEMALES CLINICAL FEATURES, AGE AND SEX DISTRIBUTIONS, RISK FACTORS AND THE TYPE OF BACTERIA ISOLATED IN PERIODONTITIS PATIENTS IN SANA'A, YEMEN

DENTAL DEFECTS WITH SUBGINGIVAL EXTENSION: A RESTORATIVE CONUNDRUM

There are situations where the subgingival margin of the restoration are unavoidable such as subgingival caries, fractures and resorption. The subgingival cavity margin creates various challenges during operative procedure and can affect periodontal health .Several restorative materials have been tried to restore cavities with subgingival margin. This paper will review the current approaches to the treatment of teeth involving root surfaces with caries, fractures, resorption and developmental defect with an objective to discuss clinical problems associated with deep subgingival margins and to have clear strategies of treatment approach in such situations.

Cytotoxic Effects on Gingival Mesenchymal Stromal Cells and Root Surface Modifications Induced by Some Local Antimicrobial Products Used in Periodontitis Treatment

(1) Background: this study aims to test the cytotoxicity of three antimicrobial products used in periodontitis treatment on gingival mesenchymal stem cells (gMSCs) and their influence on root surfaces and gMSC adhesion. We tested the null hypothesis that the effects of the antimicrobials did not differ. (2) Methods: the commercial products based on sulphonic/sulphuric acids, sodium hypochlorite and silver nanoparticles, in five different concentrations, were added to culture medium for growing gMSCs. Cell proliferation capacity was tested using the Cell Counting Kit-8 (CCK8) and their viability was determined by succinate dehydrogenase activity (MTT) assay. Scanning electron microscopy evaluated the adhesion of gMSCs on root samples treated mechanically and with commercial products. (3) Results: the products induced a dose-dependent cytotoxicity in terms of reduced proliferation and viability of gMSCs, as well as cell shape modifications. Significant differences in CCK8 values between the different commercial products were observed. Based on proliferation tests, the null hypothesis was rejected. When MTT values of the three products were compared with each other, no significant differences were observed for any of the five concentrations (p = 0.065, p = 0.067, p = 0.172, p = 0.256, p = 0.060). (4) Conclusions: the three antimicrobials had a certain degree of cytotoxicity on gMSCs. gMSCs repopulated treated root surfaces.

Minimally invasive intrasulcular tunneling technique for treatment of gingival recessions- Case Series

Modification of coronally advanced flap (CAF) by tunneling procedure was applied on four cases of gingival recession. Post-operative follow up, at different time breaks recorded full coverage of almost all receded root surfaces. The technique and the clinical outcome of this technique will be demonstrated in this case series report.

Spatial Controls of Ligamentous Tissue Orientations Using the Additively Manufactured Platforms in an In Vivo Model: A Pilot Study

The periodontal ligaments (PDLs) with specific orientations to tooth-root surfaces play a key role in generating biomechanical responses between the alveolar bone and cementum as a tooth-supporting tissue. However, control of angulations and regeneration of the ligamentous tissues within micron-scaled interfaces remains challenging. To overcome this limitation, this study investigated surface fabrications with microgroove patterns to control orientations of rat PDL cells in vitro and fibrous tissues in vivo. After being harvested, rat PDL cells were cultured and three different microgroove patterns (∠PDL groove = 0°, ∠PDL groove = 45°, and ∠PDL groove = 90°) were created by the digital slicing step in 3D printing. Cell-seeded scaffolds were subcutaneously transplanted at 3 and 6 weeks. In histology images, rat PDL cells were spatially controlled to angularly organize following the microgroove patterns and fibrous tissues were formed in scaffolds with specific angulations, which were reflected by additively manufactured microgroove topographies. Based on the results, specifically characterized surface topographies were significant to directly/indirectly organizing rat PDL cell alignments and fibrous tissue orientations. Therefore, interactions between surface topographies and tissue organizations could be one of the key moderators for the multiple tissue complex (bone-ligament-cementum) neogenesis in periodontal tissue engineering.

Avaliação in vitro da infiltração de corante após apicectomia e acabamento com diferentes tipos de brocas

Aims: evaluate the differences of infiltration by apical surface after apicoectomy and different kinds of root finishing. Materials and method: Sixty human cuspids were endodontically treated and received apicoectomy, and were divided in three alleatory groups. Group I received no finishing after the apicoectomy. Group II received standard multifluted bur finishing. Group III received the same finishing of group II, plus brunishing bur. Root surfaces and canal were coated with nail polishing except apical surface. The roots were immersed in 2% methylene blue for 72 hours. Infiltration in internal root surfaces was measured using millimetred magnifying glass by one "blind" examinator. Data were submitted to ANOVA. Results: Group I presented higher infiltration values than groups II and III. These two groups had no statistical difference, although group III showed lower values. Conclusions: finishing of apical surfaces after root resection using multifluted burs have reduced infiltration by dentine. Additional finishing using brunishing burs could even reduce the infiltration, with no statistically significant differences.

Robust Estimation of Absorbing Root Surface Distributions From Xylem Water Isotope Compositions With an Inverse Plant Hydraulic Model

The vertical distribution of absorbing roots is one of the most influential plant traits determining plant strategy to access below ground resources. Yet little is known of natural variability in root distribution since collecting field data is challenging and labor-intensive. Studying stable water isotope compositions in plants could offer a cost-effective and practical solution to estimate the absorbing root surfaces distribution. However, such an approach requires developing realistic inverse modeling techniques that enable robust estimation of rooting distributions and associated uncertainty from xylem water isotopic composition observations. This study introduces an inverse modeling method that supports the assessment of the root allocation parameter (β) that defines the exponential vertical decay of a plants’ absorbing root surfaces distribution with soil depth. The method requires measurements obtained from xylem and soil water isotope composition, soil water potentials, and sap flow velocities when plants’ xylem water is sampled at a certain height above the rooting point. In a simulation study, we show that the approach can provide unbiased estimates of β and its associated uncertainty due to measuring errors and unmeasured environmental factors that can impact the xylem water isotopic data. We also recommend improving the accuracy and power of β estimation, highlighting the need for considering accurate soil water potential and sap flow monitoring. Finally, we apply the inverse modeling method to xylem water isotope data of lianas and trees collected in French Guiana. Our work shows that the inverse modeling procedure provides a robust analytical and statistical framework to estimate β. The method accounts for potential bias due to extraction errors and unmeasured environmental factors, which improves the viability of using stable water isotope compositions to estimate the distribution of absorbing root surfaces complementary to the assessment of relative root water uptake profiles.

In Vitro Comparison of Root Surface Treatment Effect between Root Scaling with Ultrasonic Inserts and Gracey Curette and Polishing with Different Cleaning Pastes

The aim of this study was the morphological evaluation of root surfaces subjected to manual (curette) and ultrasonic (conventional and diamond tips) scaling. The surface was then polished with a rubber cup and three medium-sized pastes. Ninety teeth were randomly divided into three groups of 30 and subjected to three different root instrumentation: (1) manual instrumentation with a Gracey® curette; (2) ultrasonic instrumentation with a standard steel tip (Universal Perio S-SERIES: USU, Hu-Friedy, Chicago, IL, USA) at a power equal to 50%; and (3) with a diamond tip (Punta Piezo Serie E Scaling, Hu-Friedy, Chicago, IL, USA) at a power of 20%. Each group of the instrumented teeth was then divided in three subgroups of 10 and subjected to 30 s of rubber polishing with three different polishing pastes with medium grain sizes in single-dose cups: (1) Ultrapro Tx cool mint medium®; (2) Stomyprox media®; and (3) Nupro medium orange®. Polyether root surface replicas were then taken from all 90 samples and analyzed by SEM to evaluate surface morphology after scaling and polishing procedures. All scaling techniques caused an alteration of the root surface without statistically significant difference, whereas polishing resulted in maintenance or improvement of the surface texture.