Plaque removal by a novel prototype power toothbrush versus a manual toothbrush: A randomized, exploratory clinical study.

OBJECTIVES: This exploratory study investigated plaque removal with a prototype constant, low rotation speed Power Toothbrush (PTB) with two brushing actions: "Gumline" (head rotates in the horizontal axis) and "Interdental" (head rotates in the vertical axis). Gumline alone and "Combined" (Gumline + Interdental) modes were compared with a Reference PTB and a Reference Manual Toothbrush (MTB) after one brushing. MATERIALS AND METHODS: Thirty-nine participants were randomized to use each toothbrush once either in the sequence (A) Prototype PTB (in Gumline then Combined mode), (B) reference MTB, and (C) reference PTB or the sequence BAC. There was a minimum 3-day washout between the use of each toothbrush. Plaque removal was measured using the Rustogi Modified Navy Dental Plaque Index (RMNPI) with change from baseline investigated using an analysis of covariance model. RMNPI scores were calculated on a "whole mouth" basis and along the gingival margin and at proximal sites only. RESULTS: For the primary efficacy variable, a significant difference was found in favor of the prototype PTB in gumline mode versus the reference MTB for whole mouth plaque score (difference: -0.06; standard error: 0.014; 95% confidence interval [CI] -0.09 to -0.04; p < .0001). Similar significant differences were found in gingival margin and proximal areas (p < .0001). The prototype PTB in gumline mode removed significantly less plaque than the prototype PTB in combined mode and the reference PTB (p < .0001; whole mouth/gingival/proximal areas). The prototype PTB in combined mode removed significantly more plaque than the reference MTB (p < .0001; whole mouth/gingival/proximal areas) and the reference PTB for whole mouth (p = .0214) and gingival margin areas (p = .0010). The reference PTB also removed significantly more plaque than the reference MTB (p < .0001; whole mouth/gingival/proximal areas). All brushes were generally well-tolerated. CONCLUSION: The prototype PTB design, providing two distinct cleaning modalities, can effectively remove plaque to a significantly higher degree than an MTB and a marketed PTB, depending on mode.

Vertical bone regeneration with a simultaneous dental implant in the aesthetic zone.

Introduction: Bone defects hinder implant positioning. Vertical bone deficiency is the most challenging for clinical treatment, due to the high sensitivity of the technique and frequent intra- and postoperative complications. An alternative treatment for vertical defects is guided bone regeneration with simultaneous implantation; however, few studies have evaluated its effectiveness over time. Objective: To evaluate peri-implant tissue stability in a dental implant simultaneously positioned in an aesthetic zone of an area of zone vertical bone regeneration 3 years after functional load. Case Presentation: A 62-year-old male presented with the absence of the right lateral incisor and vertical bone defect of 3mm. His initial condition affected the relation of zenith points, causing disharmony. After case evaluation, vertical guided bone regeneration and simultaneous dental implants were performed to obtain a vertical bone gain of 3mm. The implant was rehabilitated with a zirconium crown and evaluated 3 years after functional loading. Conclusion: Vertical guided bone regeneration and simultaneous dental implant in the aesthetic zone in small bone defects (<4 mm) is an appropriate surgical and prosthetic technique to reduce surgical time, providing stability of peri-implant tissues even 3 years after functional implant loading.

Introducción: La presencia de defectos óseos dificulta el posicionamiento de los implantes, y es la deficiencia ósea vertical la que representa un mayor reto para el clínico por la alta sensibilidad de la técnica y las frecuentes complicaciones intra y posoperatorias. Una alternativa de tratamiento para los defectos verticales es la regeneración ósea guiada con implante simultáneo; sin embargo, en la literatura existen pocos estudios que evalúen su efectividad en el tiempo. Objetivo: Evaluar la estabilidad de los tejidos periimplantares en un implante dental posicionado simultáneo a la regeneración ósea vertical en una zona estética, luego de 3 años de carga funcional. Presentación de caso: Paciente masculino de 62 años que presenta ausencia del incisivo lateral derecho con un defecto óseo vertical de 3 mm, que crea una desarmonía de los puntos cenit. Posteriormente a la adecuada evaluación del caso, se decide realizar una regeneración ósea guiada vertical y colocar un implante dental simultáneo, y se obtuvo una ganancia ósea vertical de 3 mm. El implante es rehabilitado con corona en zirconio y evaluado luego de 3 años de la carga funcional. Conclusión: La regeneración ósea guiada vertical y el implante dental simultáneo en zona estética en defectos óseos pequeños (<4 mm) es una técnica quirúrgica y protésica adecuada para reducir los momentos quirúrgicos, ya que proporciona estabilidad a los tejidos periimplantares, luego de 3 años de la carga funcional del implante.

Biohybrid membranes for effective bacterial vehiculation and simultaneous removal of hexavalent chromium (CrVI) and phenol.

The aim of the present study was to obtain an effective vehiculation system in which bacterial agents could maintain viability improving their removal capacity. Herein, we present a novel biohybrid membrane of polymeric nanofibers and free-living bacteria for the simultaneous removal of pollutants. In this system, bacteria are free within the pores between the nanofibers and adsorbed to the surface of the membranes. Association between bacteria and the membranes was performed through a self-formulated medium, and the presence of the bacteria in the polymeric matrix was evidenced through atomic force microscopy (AFM). Biohybrid membranes associated with the remediation agents Bacillus toyonensis SFC 500-1E and Acinetobacter guillouiae SFC 500-1A promoted a reduction of up to 2.5 mg/L of hexavalent chromium and up to 200 mg/L of phenol after 24 h of treatment in synthetic medium containing the contaminants. Similarly, more than 46% of the hexavalent chromium and all of the phenol content were removed after treatment of a tannery effluent with initial concentrations of 7 mg/L of Cr(VI) and 305 mg/L of phenol. Counts of the remediation agents from the membranes were always above 1.107 CFU/g, also in the reutilization assays performed without reinoculation. Biohybrid membranes were hydrolysis-resistant, reusable, and effective in the simultaneous removal of contaminants for more than 5 cycles. Viability of the microorganisms was maintained after long-term storage of the membranes at 4 °C, without the use of microbiological media or the addition of cryoprotectants. Graphical abstract KEY POINTS: • Polymeric membranes were effectively associated with the SFC 500-1 remediation consortium • Biohybrid membranes removed hexavalent chromium and phenol from different matrices • Removal of contaminants was achieved in many successive cycles without reinoculation.

Reliability of the PhysioPlay™ device for assessing the reaction time of cancer patients / Confiabilidade do dispositivo PhysioPlay™ para avaliar o tempo de reação de pacientes com câncer

Objective: To determine the intra-evaluator and inter-evaluator reliability of the Physioplay-Kinect interaction and Trigno device for assessing the reaction time (RT) of cancer volunteers undergoing treatment. Methods: 46 cancer volunteers who underwent treatment modalities participated and were allocated into three groups: Chemotherapy Group (CG), Radiotherapy Group (RG), and Chemotherapy-Radiotherapy Group (CRG). The RT for all volunteers was assessed using the PhysioPlay™ and Trigno device. Results: In the intra-evaluator analysis, excellent levels of reliability (Physioplay: ICC> 0.99; Trigno 8: ICC>0.92) were observed in all groups. In the inter-evaluator analysis, excellent levels of reliability were observed in the CG (Physioplay: ICC= 0.98; Trigno 8: ICC= 0.98); excellent (Physioplay: ICC= 0.98) and good (Trigno 8: ICC= 0.44) levels in the RG; good (Physioplay: ICC= 0.49) and reasonable (Trigno 8: ICC= 0.29) levels in the CRG. Conclusion: The PhysioPlay™ and Trigno device proved to be reliable for assessing the RT of cancer volunteers undergoing treatment

Objetivo: Determinar a confiabilidade intra-avaliador e inter-avaliador da interação Physioplay-Kinect e do dispositivo Trigno para avaliar o tempo de reação (TR) de voluntários com câncer em tratamento. Métodos: 46 voluntários com câncer em tratamento participaram do estudo e foram distribuídos em três grupos: Grupo de Quimioterapia (GQ), Grupo de Radioterapia (GR), e Grupo de Quimioterapia-Radioterapia (GQR). O TR para todos os voluntários foi avaliado utilizando o dispositivo PhysioPlay™ e Trigno. Resultados: Na análise intra-avaliador, foram observados excelentes níveis de confiabilidade (Physioplay: ICC> 0,99; Trigno 8: ICC>0,92) em todos os grupos. Na análise inter-avaliador, foram observados excelentes níveis de confiabilidade no GQ (Physioplay: ICC= 0,98; Trigno 8: ICC= 0,98); excelente (Physioplay: ICC= 0,98) e bom (Trigno 8: ICC= 0,44) níveis no GR; bons (Physioplay: ICC= 0,49) e razoáveis (Trigno 8: ICC= 0,29) níveis no GQR. Conclusão: Os dispositivos PhysioPlay™ e Trigno provaram ser confiáveis para avaliar o TR de voluntários com câncer em tratamento

Polyphasic characterization and identification of the bioremediation agent Bacillus sp. SFC 500-1E.

Bacillus sp. SFC 500-1E is used for the effective treatment of tannery effluents since it consistently removes hexavalent chromium from diverse contaminated matrices. The aim of the present study was to complete identification of the strain through a polyphasic characterization, which included the pattern of carbohydrate utilization, fatty acids profile, multilocus sequence analysis, multiplex PCR profile and the analysis of the complete genome sequence. Morpho-physiological and biochemical characterization results and analysis of 16S rRNA sequences were not conclusive. The strain formed a monophyletic clade with B. toyonensis BCT-7112, B. thuringiensis MC28 and B. cereus Rock 1-3. However, genomic comparisons with type strains of B. cereus and B. thuringiensis showed that the isolated belonged to a different species. Results of this study highlight the relevance of the genome sequence of this strain, identified as Bacillus toyonensis SFC 500-1E, to expand knowledge of its bioremediation potential and to explore unknown decontamination activities.

Supervivencia de implantes dentales y complicaciones intra y posoperatorias en elevación de seno maxilar con ventana lateral e implante dental simultáneo en rebordes con reabsorción severa / Survival of dental implants and intra and post operative complications in elevation of the maxillary sinus with side window and simultaneous dental implant in sever resorbed RIMS

Objetivo: El posicionamiento de implantes dentales simultáneo a la elevación del seno maxilar en rebordes con reabsorción ósea severa (≤4 mm) es una técnica quirúrgica que disminuye los tiempos operatorios. Sin embargo, es considerada sensible por ser dependiente del operador y, en el caso que no se dé un manejo adecuado, puede presentar complicaciones. En este estudio se realiza una revisión de la literatura sobre la supervivencia de los implantes dentales y las complicaciones intra y posoperatorias en procedimientos de elevación del seno maxilar con la colocación simultánea de implante dental en rebordes con reabsorción ósea severa. Materiales y métodos: Se realizó una búsqueda bibliográfica de la literatura publicada en los últimos 10 años, durante el periodo de mayo y junio del 2019, en las bases de datos Medline­PubMed, EBSCOhost y Scopus. Esta se complementó con una búsqueda manual en revistas especializadas en periodoncia y cirugía oral Q1, posicionadas en el top 5 del 2018 en www.scimagojr.com. Se incluyeron ensayos clínicos y estudios prospectivos y retrospectivos. Se identificó 2562 artículos científicos. Tras el análisis de los títulos, la lectura de los resúmenes y los textos completos, se seleccionaron 6 artículos para el análisis de la técnica quirúrgica y 35 para complementar la información. Conclusiones: La colocación simultánea de implantes dentales a la elevación del seno maxilar es una de las técnicas utilizadas para restituir la función en el maxilar posterior. La complicación intraoperatoria más frecuente es la perforación de la membrana sinusal y la posoperatoria es la infección asociada con perforación de la membrana, o la migración del implante al seno maxilar. La supervivencia promedio del implante observada en los estudios es mayor al 94%. (AU)

Aim: The positioning of dental implants simultaneous to the elevation of the maxillary sinus in ridges with severe bone resorption (≤4mm) is a surgical technique that reduces operative times. However, it is considered sensitive, being dependent on the operator, and in the absence of appropriate handling, complications can occur. This study aimed to provide a review of the literature on the survival of dental implants and intra- and post-operative complications in maxillary sinus lift procedures with the simultaneous placement of a dental implant in ridges with severe bone resorption. Materials and methods: A bibliographic search of the literature published in the last 10 years in the Medline-Pubmed, EBSCO HOST and SCOPUS databases was carried out from May to June 2019. This was complemented with a manual search in journals specialized in Periodontology and Oral Surgery Q1, positioned in the Top 5 of the year 2018 at www.scimagojr.com. Prospective, retrospective and clinical trials were included 2562. A total of 2562 prospective, retrospective and clinical trials were included. After analyzing the titles and reading the abstracts and full texts, 6 articles were selected for analysis of the surgical technique and 35 to complement information. Conclusions: The placement of dental implants simultaneously with maxillary sinus elevation is one of the techniques used to restore function in the posterior maxilla. The most frequent intra-operative complication is perforation of the sinus membrane, and the most common post-operative complication is infection associated with perforation of the membrane, or migration of the implant to the maxillary sinus. The average implant survival reported is greater than 94%. (AU)

Impact assessment of bioaugmented tannery effluent discharge on the microbiota of water bodies.

Effluents are commonly discharged into water bodies, and in order for the process to be as environmentally sound as possible, the potential effects on native water communities must be assessed alongside the quality parameters of the effluents themselves. In the present work, changes in the bacterial diversity of streamwater receiving a tannery effluent were monitored by high-throughput MiSeq sequencing. Physico-chemical and microbiological parameters and acute toxicity were also evaluated through different bioassays. After the discharge of treated effluents that had been either naturally attenuated or bioaugmented, bacterial diversity decreased immediately in the streamwater samples, as evidenced by the over-representation of taxa such as Brachymonas, Arcobacter, Marinobacterium, Myroides, Paludibacter and Acinetobacter, typically found in tannery effluents. However, there were no remarkable changes in diversity over time (after 1 day). In terms of the physico-chemical and microbiological parameters analyzed, chemical oxygen demand and total bacterial count increased in response to discharge of the treated effluents. No lethal effects were observed in Lactuca sativa L. seeds or Rhinella arenarum embryos exposed to the streamwater that had received the treated effluents. All of these results contribute to the growing knowledge about the environmental safety of effluent discharge procedures.

In situ efficacy of an experimental toothpaste on enamel rehardening and prevention of demineralisation: a randomised, controlled trial.

BACKGROUND: A novel sodium fluoride toothpaste containing lactate ion and polyvinylmethylether-maleic anhydride has been developed to promote enamel remineralisation and resistance to demineralisation. In this in situ study, we compared this toothpaste ('Test') with a stannous fluoride-zinc citrate (SnF2-Zn) toothpaste ('Reference') (both 1100-1150 ppm fluoride) and a fluoride-free toothpaste ('Placebo') using an enamel dental erosion-rehardening model. METHODS: In each phase of this randomised, investigator-blind, crossover study, participants wore palatal appliances holding bovine enamel specimens with erosive lesions. They brushed their natural teeth with either the Test, Reference or Placebo toothpastes, then swished the resultant slurry. Specimens were removed at 2 h and 4 h post-brushing and exposed to an in vitro acid challenge. Surface microhardness was measured at each stage; enamel fluoride uptake was measured after in situ rehardening. Surface microhardness recovery, relative erosion resistance, enamel fluoride uptake and acid resistance ratio were calculated at both timepoints. RESULTS: Sixty two randomised participants completed the study. Test toothpaste treatment yielded significantly greater surface microhardness recovery, relative erosion resistance and enamel fluoride uptake values than either Reference or Placebo toothpastes after 2 and 4 h. The acid resistance ratio value for Test toothpaste was significantly greater than either of the other treatments after 2 h; after 4 h, it was significantly greater versus Placebo only. No treatment-related adverse events were reported. CONCLUSIONS: In this in situ model, the novel-formulation sodium fluoride toothpaste enhanced enamel rehardening and overall protection against demineralisation compared with a fluoride-free toothpaste and a marketed SnF2-Zn toothpaste. TRIAL REGISTRATION: ClinicalTrials.gov; NCT03296072; registered September 28, 2017.

Three randomized studies of dentine hypersensitivity reduction after short-term SnF2 toothpaste use.

AIM: To evaluate effects of a 0.454% stannous fluoride test toothpaste on dentine hypersensitivity (DH) applied by fingertip, then 3 days' brushing, versus a sodium monofluorophosphate-based control. MATERIALS AND METHODS: In three randomized clinical studies, DH was assessed using evaporative (Schiff scale) and tactile (Yeaple probe) stimuli. Participants applied toothpaste to two sensitive teeth by fingertip (60 s each); DH was re-assessed, prior to brushing. Test treatment participants brushed their sensitive teeth, with all participants then brushing all teeth for ≥60 s, twice daily for 3 days. DH was re-assessed. Data were analysed by study and then pooled. RESULTS: In two studies, test treatment significantly reduced DH versus control treatment after fingertip application and 3 days' brushing (both measures). In one study, both treatments significantly reduced DH without between-treatment differences. Mean Schiff differences (95% confidence intervals) for fingertip/3d were as follows: Study 1: -0.09 (-0.280, 0.092)/ -0.18 (-0.442, 0.072); Study 2: -0.72 (-0.839, -0.610)/ -1.02 (-1.150, -0.882); and Study 3: -0.26 (-0.387, -0.123)/ -0.92 (-1.055, -0.793). Pooled analysis indicated test treatment significantly reduced DH versus control (both timepoints, both measures). Toothpastes were generally well-tolerated. CONCLUSION: Studies indicated that single, fingertip application of a SnF2 toothpaste reduced DH versus a control. DH relief increased over 3 days.

Randomised clinical studies investigating immediate and short-term efficacy of an occluding toothpaste in providing dentine hypersensitivity relief.

BACKGROUND: Dentine hypersensitivity (DH) can occur after gum recession or enamel loss and may impact quality of life. Treatments include toothpastes that decrease DH by occluding dentine tubules. One effective occluding ingredient used in toothpastes is stannous fluoride (SnF2), but this can be unstable in aqueous formulation. These three studies aimed to characterise the short-term effects of an experimental, anhydrous SnF2 dentifrice on DH. METHODS: Three examiner-blind, parallel-group studies evaluated DH in participants with the condition after a single brushing and after 3d brushing with an experimental anhydrous 0.454% SnF2/polyphosphate toothpaste (Test) or a toothpaste containing 0.76% sodium monofluorophosphate (Control). Test treatment participants brushed two pre-identified sensitive teeth first, then their remaining dentition for ≥1 min ('focused brushing'). Control treatment participants brushed their whole dentition for ≥1 min. DH was measured after single brushing and after 3d twice-daily use, via evaporative (air) (Schiff Sensitivity Scale) and tactile (Yeaple probe) stimuli and analysed using an ANCOVA model. RESULTS: In all studies, after 3d treatment, the Test toothpaste/brushing regimen significantly reduced DH compared to the Control regimen by both evaporative and tactile stimuli assessment (p < 0.0001 for all). The Test regimen also significantly reduced DH from baseline at both time-points by both measures in all studies (p < 0.0001 for all). Mean Schiff sensitivity score differences (95% confidence intervals) between Test and Control regimens after 3d were: Study 1: - 0.45 (- 0.577, - 0.319); Study 2: - 0.40 (- 0.505, - 0.300); Study 3: - 1.31 (- 1.500, - 1.128). Mean tactile score differences were: Study 1: 11.30 (7.927, 14.662); Study 2: 3.57 (2.531, 4.614); Study 3: 24.54 (20.349, 28.736). After single use, in Studies 2 and 3, the Test toothpaste/brushing regimen significantly reduced DH versus Control by both measures (p < 0.001 for all); in Study 1, treatment differences were not significant. Toothpastes were generally well-tolerated. CONCLUSIONS: Taken together, these studies indicated focused brushing with an experimental anhydrous 0.454% SnF2/polyphosphate toothpaste reduces DH compared to brushing with a conventional toothpaste after single use, with greater reduction after 3d. TRIAL REGISTRATION: Registrations at ClinicalTrials.gov : Study 1: NCT02832375 (registered 26.July.2016); Study 2: NCT02731833 (registered 26.April.2016); Study 3: NCT02923895 (registered 5.October.2016).

How the bacterial community of a tannery effluent responds to bioaugmentation with the consortium SFC 500-1. Impact of environmental variables.

Bioaugmentation with the consortium SFC 500-1 is a promising alternative to remediate wastewaters, such as tannery effluents. With the aim of assessing the changes produced in response to bioaugmentation, bacterial 16S rDNA genes were sequenced with Illumina MiSeq Platform. Additionally, bacterial and fungal groups were analyzed through standard culture dependent methods. The impact of diverse physico-chemical and microbiological parameters on the prokaryotic diversity was also evaluated throughout. Bacteroidetes, Firmicutes and Proteobacteria, represented together up to 91% of the total number of sequences obtained from the tannery effluent. Diversity decreased immediately after inoculation, due to an increase in the representation of the taxa to which the added consortium belongs. However, bioaugmentation produced no greater variations since only a 10% of unique operational taxonomic units were found in the inoculated treatment. An increase in the abundance of Myroides and a reduction in the representation of Proteiniclasticum and Halomonas were major observed variations. On the other hand, pH and dissolved oxygen constituted main environmental factors affecting the structure of the prokaryotic communities. In all treatments yeasts increased over time, to the detriment of filamentous fungi. Together, data from this report may contribute to the development of improved bioremediation strategies of industrial wastewaters.

Laboratory and field microcosms as useful experimental systems to study the bioaugmentation treatment of tannery effluents.

Tannery effluents require effective treatment prior to their final disposal, and the use of native bacterial consortia could be an appropriate strategy for this purpose. In the present work, consortium SFC 500-1 was found to be highly tolerant to different metals, metalloids and aromatic compounds like phenols. It was also able to remove the black dye commonly used in tanneries. Moreover, it promoted a significant reduction in chemical oxygen demand and exhibited high capability for the simultaneous removal of Cr(VI) and phenol. However, the effectiveness of the remediation processes markedly varied from one experimental system (Erlenmeyer flasks) to another (field microcosm system), highlighting the importance of moving from a small-scale study system to one involving more realistic environmental scenarios. In addition, we found a decrease in the toxicity of the effluent treated with consortium SFC 500-1. Taken together, our results indicate that this consortium possesses great potential for the treatment of tannery effluents. We conclude that for the development of a bioremediation strategy, it is necessary to develop experiments at a larger scale under conditions similar to those of the original system, in order to complete the scenario first created by in vitro approaches.

Impact of frequency of denture cleaning on microbial and clinical parameters - a bench to chairside approach.

Objective: Robust scientific and clinical evidence of how to appropriately manage denture plaque is lacking. This two-part study (i) developed an in vitro model of denture plaque removal, and (ii) assessed effectiveness of these approaches in a randomised clinical trial. Method: (i) a complex denture plaque model was developed using the dominant microbial genera from a recent microbiome analyses. Biofilms formed on polymethylmethacrylate were brushed daily with a wet toothbrush, then either treated daily for 5 days or only on Days 1 and 5 with Polident® denture cleanser tablets (3 min soaking). Quantitative and qualitative microbiological assessments were performed. (ii), an examiner-blind, randomised, crossover study of complete maxillary denture wearers was performed (n = 19). Either once-daily for 7 days or on Day 7 only, participants soaked dentures for 15 min using Corega® denture cleansing tables, then brushed. Denture plaque microbiological assessment used sterilized filter paper discs. Results: The in vitro model showed daily cleaning with denture cleanser plus brushing significantly reduced microbial numbers compared to intermittent denture cleaning with daily brushing (p < 0.001). The clinical component of the study showed a statistically significant reduction in denture plaque microbial numbers in favour of daily versus weekly treatment (aerobic bacteria p = 0.0144). Both in vitro and in vivo studies showed that denture plaque biofilm composition were affected by different treatment arms. Conclusions: This study demonstrated that daily denture cleansing regimens are superior to intermittent denture cleansing, and that cleansing regimens can induce denture plaque compositional changes. Clinicaltrials.gov registration: NCT02780661.

Light activated antimicrobial agents can inactivate oral malodour causing bacteria.

Oral malodour is a common condition which affects a large proportion of the population, resulting in social, emotional and psychological stress. Certain oral bacteria form a coating called a biofilm on the tongue dorsum and degrade organic compounds releasing volatile sulfur compounds that are malodourous. Current chemical treatments for oral malodour such as mouthwashes containing chlorhexidine or essential oils, are not sufficiently effective at reducing the bacterial load on the tongue. One potential alternative to current chemical treatments for oral malodour is the use of light activated antimicrobial agents (LAAAs), which display no toxicity or antimicrobial activity in the dark, but when exposed to light of a specific wavelength produce reactive oxygen species which induce damage to target cells in a process known as photodynamic inactivation. This study aimed to determine whether oral malodour causing bacteria were susceptible to lethal photosensitization. Five bacterial species that are causative agents of oral malodour were highly sensitive to lethal photosensitization and were efficiently killed by methylene blue in conjunction with 665 nm laser light. Between 4.5-5 log10 reductions in the number of viable bacteria were achieved with 20 µM methylene blue and 14.53 J cm-2 laser light for Porphyromonas gingivalis, Prevotella intermedia, Peptostreptococcus anaerobius and Solobacterium moorei. The number of viable cells fell below the limit of detection in the case of Fusobacterium nucleatum. These findings demonstrate that methylene blue in combination with 665 nm laser light is effective at killing bacteria associated with oral malodour, suggesting photodynamic therapy could be a viable treatment option for oral malodour.

Efficient CO2 fixation by surface Prochlorococcus in the Atlantic Ocean.

Nearly half of the Earth's surface is covered by the ocean populated by the most abundant photosynthetic organisms on the planet--Prochlorococcus cyanobacteria. However, in the oligotrophic open ocean, the majority of their cells in the top half of the photic layer have levels of photosynthetic pigmentation barely detectable by flow cytometry, suggesting low efficiency of CO2 fixation compared with other phytoplankton living in the same waters. To test the latter assumption, CO2 fixation rates of flow cytometrically sorted (14)C-labelled phytoplankton cells were directly compared in surface waters of the open Atlantic Ocean (30°S to 30°N). CO2 fixation rates of Prochlorococcus are at least 1.5-2.0 times higher than CO2 fixation rates of the smallest plastidic protists and Synechococcus cyanobacteria when normalised to photosynthetic pigmentation assessed using cellular red autofluorescence. Therefore, our data indicate that in oligotrophic oceanic surface waters, pigment minimisation allows Prochlorococcus cells to harvest plentiful sunlight more effectively than other phytoplankton.

Flow cytometric identification of Mamiellales clade II in the Southern Atlantic Ocean.

Flow cytometric sorting, based on cellular optical properties and macromolecule content, has been successfully employed to taxonomically affiliate bacterioplankton. However, this approach has not been much used for eukaryotic plankton. To redress this imbalance, we identified a conspicuous group of red autofluorescent picoplankton in surface waters of the South Atlantic Ocean. Using catalysed reporter deposition fluorescence in situ hybridization, virtually, all cells sorted from that group were affiliated with the Mamiellales clade II (84 ± 4%, division Chlorophyta) with a size of 1.6 ± 0.03 µm. Based on electron microscopy, the Mamiellales clade II-sorted cells have a simple morphology with apparently no scales, flagella or surface features. Their latitudinal distribution resembled the distribution of Synechococcus with very low concentrations in the surface waters of the Southern subtropical gyre (0.6-1.6 × 10(3) cells mL(-1)) and increased concentrations in the Southern temperate waters 8.3 × 10(3) cells mL(-1). Identification of the flow cytometric group as Mamiellales clade II allowed us to characterize the morphology of these enigmatic uncultured picoplanktonic cells by electron microscopy and to determine their apparent preference for temperate rather than subtropical oceanic photic waters.

Comparable light stimulation of organic nutrient uptake by SAR11 and Prochlorococcus in the North Atlantic subtropical gyre.

Subtropical oceanic gyres are the most extensive biomes on Earth where SAR11 and Prochlorococcus bacterioplankton numerically dominate the surface waters depleted in inorganic macronutrients as well as in dissolved organic matter. In such nutrient poor conditions bacterioplankton could become photoheterotrophic, that is, potentially enhance uptake of scarce organic molecules using the available solar radiation to energise appropriate transport systems. Here, we assessed the photoheterotrophy of the key microbial taxa in the North Atlantic oligotrophic gyre and adjacent regions using (33)P-ATP, (3)H-ATP and (35)S-methionine tracers. Light-stimulated uptake of these substrates was assessed in two dominant bacterioplankton groups discriminated by flow cytometric sorting of tracer-labelled cells and identified using catalysed reporter deposition fluorescence in situ hybridisation. One group of cells, encompassing 48% of all bacterioplankton, were identified as members of the SAR11 clade, whereas the other group (24% of all bacterioplankton) was Prochlorococcus. When exposed to light, SAR11 cells took 31% more ATP and 32% more methionine, whereas the Prochlorococcus cells took 33% more ATP and 34% more methionine. Other bacterioplankton did not demonstrate light stimulation. Thus, the SAR11 and Prochlorococcus groups, with distinctly different light-harvesting mechanisms, used light equally to enhance, by approximately one-third, the uptake of different types of organic molecules. Our findings indicate the significance of light-driven uptake of essential organic nutrients by the dominant bacterioplankton groups in the surface waters of one of the less productive, vast regions of the world's oceans-the oligotrophic North Atlantic subtropical gyre.

Genomic content of uncultured Bacteroidetes from contrasting oceanic provinces in the North Atlantic Ocean.

Bacteroidetes are widespread in marine systems where they play a crucial role in organic matter degradation. Whole genome analysis of several strains has revealed a broad glycolytic and proteolytic potential. In this study, we used a targeted metagenomic approach to investigate the degradation capabilities of distinct Bacteroidetes clades from two contrasting regions of the North Atlantic Ocean, the Polar Biome (BPLR) and the North Atlantic Subtropical (NAST). We present here the analysis of 76 Bacteroidetes fosmids, of which 28 encode the 16S rRNA gene as phylogenetic marker, and their comparison to complete Bacteroidetes genomes. Almost all of the 16S rRNA harbouring fosmids belonged to clades that we previously identified in BPLR and NAST. The majority of sequenced fosmids could be assigned to Bacteroidetes affiliated with the class Flavobacteria. We also present novel genomic information on the classes Cytophagia and Sphingobacteria, suggesting a capability of the latter for attachment to algal surfaces. In our fosmid set we identified a larger potential for polysaccharide degradation and cell surface attachment in the phytoplankton-rich BPLR. Particularly, two flavobacterial fosmids, one affiliated with the genus Polaribacter, showed a whole armoury of enzymes that likely function in degradation of sulfated polysaccharides known to be major constituents of phytoplankton cell walls. Genes involved in protein and peptidoglycan degradation, although present in both fosmid sets, seemed to have a slight preponderance in NAST. This study provides support for the hypothesis of a distinct specialization among marine Bacteroidetes for the degradation of certain types of polymers.

Bacterioplankton diversity and community composition in the Southern Lagoon of Venice.

The Lagoon of Venice is a large water basin that exchanges water with the Northern Adriatic Sea through three large inlets. In this study, the 16S rRNA approach was used to investigate the bacterial diversity and community composition within the southern basin of the Lagoon of Venice and at one inlet in October 2007 and June 2008. Comparative sequence analysis of 645 mostly partial 16S rRNA gene sequences indicated high diversity and dominance of Alphaproteobacteria, Gammaproteobacteria and Bacteroidetes at the lagoon as well as at the inlet station, therefore pointing to significant mixing. Many of these sequences were close to the 16S rRNA of marine, often coastal, bacterioplankton, such as the Roseobacter clade, the family Vibrionaceae, and class Flavobacteria. Sequences of Actinobacteria were indicators of a freshwater input. The composition of the bacterioplankton was quantified by catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) with a set of rRNA-targeted oligonucleotide probes. CARD-FISH counts corroborated the dominance of members of the phyla Alphaproteobacteria, Gammaproteobacteria and Bacteroidetes. When assessed by a probe set for the quantification of selected clades within Alphaproteobacteria and Gammaproteobacteria, bacterioplankton composition differed between October 2007 and June 2008, and also between the inlet and the lagoon. In particular, members of the readily culturable copiotrophic gammaproteobacterial genera Vibrio, Alteromonas and Pseudoalteromonas were enriched in the southern basin of the Lagoon of Venice. Interestingly, the alphaproteobacterial SAR11 clade and related clusters were also present in high abundances at the inlet and within the lagoon, which was indicative of inflow of water from the open sea.

Distinct flavobacterial communities in contrasting water masses of the north Atlantic Ocean.

Members of the class Flavobacteria in the phylum Bacteroidetes are among the most abundant picoplankton in coastal and polar oceans. Their diversity is high in marine waters. However, quantitative information about distribution patterns of flavobacterial clades is scarce. We analyzed the diversity and clade-specific abundances of individual Flavobacteria in different oceanic provinces in the North Atlantic Ocean. Samples were taken along the 30 degrees W meridian between the East Greenland current and the North Atlantic subtropical gyre. Comparative sequence analysis of 16S ribosomal RNA (rRNA) gene libraries revealed high diversity and significant spatial variability within the class Flavobacteria. Published and newly designed oligonucleotide probes were used to enumerate eleven flavobacterial clades by catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). We found that different provinces harbor distinct flavobacterial communities. Clade DE2 accounted for a substantial fraction of total Flavobacteria only in the Polar Biome (BPLR), whereas the VISION clades VIS1 and VIS4 significantly increased in the Arctic (ARCT) province. Members of the genus Polaribacter were the most abundant clade in all the water masses analyzed, with highest absolute numbers in BPLR and ARCT. We improved the CARD-FISH protocol to quantify the rare clades VIS2, VIS3, VIS5 and VIS6, which were present in abundances below 0.5%. They all showed pronounced regional distribution patterns. Microscopic analysis proved a specific enrichment of Flavobacteria in the phycosphere of nanophytoplankton of BPLR and ARCT. Our results suggest that different marine flavobacterial clades have distinct niches and different life strategies.