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1.
Bioresour Technol ; 295: 122251, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31630002

RESUMO

Two TaqMan® qPCR assays were developed to specifically quantify the absolute abundance of Scenedesmus obliquus and Chlorella vulgaris in mixed-species algal biofilms by targeting the psbA gene. Standard curves were developed with amplification efficiencies of 92.4% and 96.6% for S. obliquus and C. vulgaris, respectively, and an R2 value of 0.99 for both. Calibration curves for estimating absolute cell abundances resulted in slopes of 0.98 and 1.11 for C. vulgaris and S. obliquus, respectively, and an R2 value of 0.95 for both. The assays were applied to cultivated mixed-species biofilms and approximately 107 cells of each algal species were quantified when 107 cells were added into biofilms. The developed qPCR assays were concluded to be specific and accurate for the quantification of S. obliquus and C. vulgaris in mixed-species biofilms. This will contribute to the control and optimization of algal cultivation systems for the production of algal biofuels and bioproducts.


Assuntos
Chlorella vulgaris , Microalgas , Scenedesmus , Biofilmes , Biocombustíveis , Biomassa , Clorofíceas
2.
Bioresour Technol ; 295: 122298, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31675521

RESUMO

Four lab-scale moving bed biofilm reactors (MBBRs) were built to treat simulated wastewater containing typical pharmaceuticals and personal care products (PPCPs). The efficiency in removing different PPCPs at different concentrations (1, 2 and 5 mg/L) and their effects on the performance of MBBRs were investigated. Results showed that the average removal efficiencies of sulfadiazine, ibuprofen and carbamazepine were 61.1 ±â€¯8.8%, 74.9 ±â€¯8.8% and 28.3 ±â€¯7.4%, respectively. Compared to the reactor without PPCPs, the total nitrogen (TN) removal efficiency of the reactors containing sulfadiazine, ibuprofen and carbamazepine declined by 21%, 30% and 42%, respectively. Based on the microbial community analysis, increasing the PPCPs concentration within a certain range (<2 mg/L) could stimulate microbial growth and increase microbial diversity yet the diversity reduced when the concentration (5 mg/L) exceeded the tolerance of microorganisms. Furthermore the presence and degradation of different PPCPs resulted in a different kind of microbial community structure in the MBBRs.


Assuntos
Reatores Biológicos , Microbiota , Biofilmes , Nitrogênio , Eliminação de Resíduos Líquidos , Águas Residuárias
3.
Bioresour Technol ; 295: 122271, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31677806

RESUMO

Investigations on microbial electrocatalysis as a strategy for enhancing the rates of substrate utilization leading to enhanced yield of biomass and enhanced biofilm formation are reported. A thermophilic Geobacillus sp. strain WSUCF1 (60 °C), a potential lignocellulose degrading microorganism was used as the electrocatalyst. Glucose, cellulose, and corn stover were used as the feedstocks. The results of this investigation showed that applying the oxidation potential of -0.383 mV (vs PRE) increased the glucose utilization and COD removal by 25.5% and 29.7% respectively. The bioelectrocatalysis strategy also increased the biomass yield by 81.2, 42.1, and 49.5% in the case of systems fed with glucose, cellulose, and corn stover, respectively, when compared with the systems without applied oxidation potential. This is the first work reporting the effects of applied oxidation potential on increasing the rates of degradation of lignocellulosic biomass and enhanced biofilm formation.


Assuntos
Geobacillus , Biofilmes , Biomassa , Celulose , Lignina , Zea mays
4.
Bioresour Technol ; 295: 122302, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31678888

RESUMO

The performance of pollutant removals, activated sludge characteristics, and microbial communities of two biofilm membrane bioreactors coupled with pre-anoxic tanks (BF-AO-MBRs) (one using fiber bundle bio-carriers (FB-MBR) and the other using suspended bio-carriers (MB-MBR)) were compared at the salinity between zero and 60 g/L. At all salinities, three bioreactors showed good COD average removal efficiencies (>94.1%), and FB-MBR showed the best TN removal efficiency (90.4% at 30 g/L salinity). Moreover, FB-MBR had the faster process start-up time and better salt shock resistance. At high salinities (30-60 g/L), more extracellular polymeric substances were produced by the BF-AO-MBRs to avoid the penetration of salt and protect the bacterial community. Because of the different attachment patterns of biofilms, the microbial community structure in the FB-MBR exposed to 30 g/L salinity had higher nitrite-oxidizing/ammonia-oxidizing bacteria ratio (6.44) with more abundance of denitrifiers, which contribute to higher TN removal efficiency and lower nitrite accumulation.


Assuntos
Microbiota , Águas Residuárias , Biofilmes , Reatores Biológicos , Membranas Artificiais , Esgotos , Eliminação de Resíduos Líquidos
5.
Water Res ; 168: 115159, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31614234

RESUMO

Worldwide, it is common that the drinking water distribution systems (DWDSs) may be subjected to changes of supply water quality due to the needs of upgrading the treatment processes or switching the source water. However, the potential impacts of quality changed supply water on the stabilized ecological niches within DWDSs and the associated water quality deterioration risks were poorly documented. In the present study, such transition effects caused by changing the supply water quality that resulted from destabilization of biofilm and loose deposits in DWDS were investigated by analyzing the physiochemical and microbiological characteristics of suspended particles before (T0), during (T3-weeks) and after upgrading the treatments (T6-months) in an unchlorinated DWDS in the Netherlands. Our results demonstrated that after 6 months' time the upgraded treatments significantly improved the water quality. Remarkably, water quality deterioration was observed at the initial stage when the quality-improved treated water distributed into the network at T3-weeks, observed as a spike of total suspended solids (TSS, 50-260%), active biomass (ATP, 95-230%) and inorganic elements (e.g. Mn, 130-250%). Furthermore, pyrosequencing results revealed sharp differences in microbial community composition and structure for the bacteria associated with suspended particles between T0 and T3-weeks, which re-stabilized after 6 months at T6-months. The successful capture of transition effects was especially confirmed by the domination of Nitrospira spp. and Polaromonas spp. in the distribution system at T3-weeks, which were detected at rather low relative abundance at treatment plant. Though the transitional effects were captured, this study shows that the introduction of softening and additional filtration did not have an effect on the water quality for the consumer which improved considerably after 6-months' period. The methodology of monitoring suspended particles with MuPFiSs and additional analysis is capable of detecting transitional effects by monitoring the dynamics of suspended particles and its physiochemical and microbiological composition.


Assuntos
Água Potável , Biofilmes , Países Baixos , Microbiologia da Água , Qualidade da Água , Abastecimento de Água
6.
Water Res ; 168: 115163, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31614239

RESUMO

Respiratory infections from opportunistic bacterial pathogens (OBPs) have heightened research interests in drinking water distribution systems, premise plumbing, and point-of-use technologies. In particular, biofilm growth in showerheads increases OBP content, and inhalation of shower aerosols is a major exposure route for Legionellae and Mycobacteria infections. Incorporation of UVC LEDs into showerheads has thus been proposed as a point-of-use option for healthcare facilities. Herein we have examined incongruities between the nature of OBP contamination in shower water and the hypothetical application of conventional UV disinfection engineering concepts. Effective UV dosing within showerheads must overcome significant shielding effects imparted by the biological matrices in which common OBPs reside, including biofilm particles and protozoan hosts. Furthermore, prevention of biofilm growth in showerhead interiors requires a different UV irradiation approach and is lacking in established design parameters. Development of showerhead devices is also likely to face a trade-off between bathing functionality and simpler form factors that are more conducive to internal UV irradiation.


Assuntos
Legionella , Bactérias , Biofilmes , Desinfecção , Desenho de Equipamento , Engenharia Sanitária , Microbiologia da Água
7.
Water Res ; 168: 115181, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31630018

RESUMO

In this study, zwitterionic polymer brushes with controlled architecture were grafted on the surface of gravity-driven membrane (GDM) via surface-initiated reaction to impart antifouling property. A variety of membrane characterization techniques were conducted to demonstrate the successful functionalization of zwitterionic polymers on PVDF hollow fiber membrane. The membrane underwent 90 min of reaction time possessing strong hydrophilicity and high permeability was determined as the optimal modified membrane. Long-term GDM dynamic fouling experiments operated for 30 days using sewage wastewater as feed solution indicated zwitterionic polymer modified membrane exhibit excellent membrane fouling resistance thus enhanced stable flux. Confocal laser scanning microscopy (CLSM) imaging implied that zwitterionic polymer modification significantly inhibit the adsorption of extracellular polymeric substances (EPS) which dominates fouling propensity, resulting in the formation of a thin biofilm with high porosity under synthetic functions of foulants deposition and microbial activities. Interfacial free energy prediction affirmed the presence of zwitterionic functional layer on membrane surface could substantially decrease the interactions (e.g., electrostatic attractions and hydrophobic effects) between membrane and foulants, thereby reduced flux decline and high stable flux. Our study suggests surface hydrophilic functionalization shows promising potential for improving the performance of ultra-low pressure filtration.


Assuntos
Membranas Artificiais , Polímeros , Biofilmes , Filtração , Esgotos
8.
Klin Lab Diagn ; 64(10): 632-634, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31742958

RESUMO

Current methods of biofilm imaging do not support a differentiated assessment of its composition, since it is not possible to establish a substrate stained with crystal violet, as this dye can form complexes with both intracellular and extracellular structures. This approach does not adequately assess the anti-biofilm effects of drugs, while the results of studying the interaction of drugs with biofilm components can ensure their most correct choice. The aim of investigation was to study the possibility of applying the original modification of the current method to determine the ratio of the cellular part and the matrix of biofilms of gram-positive microorganisms. The biofilm components were analyzed using a two-step approach, when prepared biofilms of gram-positive microorganisms were stained with crystal violet for 5 minutes, followed by fixing the dye in bacterial cells with iodine solution, and then the colored products were dissolved with 95% alcohol: matrix components for 1 minute, total biofilm for 15 minutes, after which the composition of biofilms was estimated by the formula: M=(OP1/OP15)×100, Kb=100-M, where M is the proportion of the matrix,%; Kb - the proportion of the cellular component,%; OP1 - optical density of samples, when alcohol was allowed to dissolve the colored product for no more than 1 minute; OP15 - was the optical density of samples, when alcohol is allowed to dissolve the colored product for 15 minutes. It was shown that in the composition of the biofilm formed by the collection strain, the proportion of the matrix was 13.2%, and the cellular component accounted for 86.8%. When the same strain cultivated in the presence of an antibiotic, an increase in the biofilm matrix was observed, which is probably due to the compensatory response of the microorganism to the action of the antibiotic. The proposed approach to the study of biofilms makes it possible to evaluate its component composition. Obtaining additional information in this way can provide, inter alia, an increase in the effectiveness of antimicrobial therapy while reducing the study time.


Assuntos
Biofilmes , Bactérias Gram-Positivas/classificação , Coloração e Rotulagem
9.
Klin Lab Diagn ; 64(11): 681-685, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31747498

RESUMO

When the nasopharynx is colonized with toxigenic strains of the diphtheria pathogen, toxin is released, which contributes to the death of epithelial cells. But in bacterial carriers, the development of the clinical picture of the disease does not occur. This is due to the peculiarities of the state of their immune system, as well as the peculiarities of the production of diphtheria exotoxin by corynebacteria in the biofilm. Goal. Determining the nature of the cytopathic effect of C. diphtheriae as part of a biofilm in CHO-K1 cell culture. The planktonic and biofilm (120- and 720-hour) cultures of the strains were studied: C. diphtheriae gravis tox+ № 665, C. diphtheriae gravis tox+ № 6765, C. diphtheriae mitis tox+ № 269, C. diphtheriae gravis tox+ isolated from a patient with a diagnosis Localized oropharyngeal diphtheria C. diphtheriae gravis with a silent tox-gene. Biofilm (120- and 720-hour) cultures of diphtheria pathogen strains were obtained according to the Watnik method. The cytopathic effect of corynebacterial strains was studied on a CHO-K1 cell culture, taking into account in an inverted microscope. When studying the cytopathic effect of planktonic cultures of toxigenic strains of corynebacteria, it was found that the number of living CHO-K1 cells after 24 hours was insignificant (25.3±1.2%) and sharply decreased (2.5±0.5%) after 72 hours of cultivation. Under the influence of biofilm and, especially, 720-hour cultures, a different cytopathic effect dynamics was found: the number of living cells after 24 hours remained significant (82.5±2.2%), while at 72-hour it decreased to 25.0±3.0%. In the study of filtrates of planktonic and biofilm cultures of C. diphtheriae strain with a «silent¼ tox-gene, similar patterns were revealed. However, the number of live CHO-K1 cells when exposed to the filtrate of a 720-hour biofilm culture was significantly higher (p≤0.05) than when studying toxigenic strains of corynebacteria. Considering the nature of the cytopathic action, it was found that planktonic cultures of toxigenic strains of corynebacteria are characterized by a change in the cell monolayer, manifested by their thinning and elongation. The study of 720-hour biofilm cultures at 72-hour exposure revealed the appearance of a large number of rounded cells (63-69%). The cytopathic effect, formed under the influence of filtrates of planktonic and biofilm cultures of C. diphtheriae with a «silent¼ tox-gene, as well as strains of non-diphtheria corynebacteria, is characterized by rounding of cells and the formation of symplasts. In the biofilm, the intensity of the cytopathic effect of toxigenic C. diphtheriae strains and C. diphtheriae strain with a silent tox-gene decreased. CPD, manifested by thinning and lengthening of CHO-K1 cells, is associated with the action of diphtheria exotoxin, and rounding is associated with corynebacterial enzymes and, apparently, fragments of surface structures - adhesins. Decreased release of toxin and enzymes beyond the C. bihfilm matrix is a significant cause of the «asymptomatic¼ carriage of diphtheria.


Assuntos
Biofilmes , Corynebacterium diphtheriae/patogenicidade , Difteria , Animais , Infecções Assintomáticas , Células CHO , Cricetulus , Toxina Diftérica , Humanos
10.
J Photochem Photobiol B ; 201: 111667, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31683167

RESUMO

Titanium dioxide nanoparticles (TiO2-NPs) were synthesized using the aqueous leaf extract of Aloe barbadensis as a reducing and fabricating agent. The biosynthesis of the TiO2-NPs was initially confirmed by UV-vis spectroscopy. Based on the HRTEM and FESEM analysis, the biosynthesized NPs were found to be polydispersed and predominantly spherical in shape, with an average size of ~20 nm. A sharp and strong characteristic peaks of titanium (Ti) and oxygen (O) observed in the EDS pattern confirmed the synthesis of the TiO2-NPs. The FTIR spectroscopy suggested the presence of terpenoids, flavonoids and proteins which might be responsible for the biosynthesis and fabrication of the TiO2-NPs. The crystalline nature of the synthesized TiO2-NPs constituting of a mixture of brookite, anatase, and rutile phases was indicated by the XRD pattern. The spectral window around 180-1000 cm-1 covered the high-frequency Raman spectra of the TiO2-NPs. The Raman vibrational spectrum showed four Eg modes centered at 197.84, 399.24, 514.50, and 641.58 cm-1 representing the anatase phase of TiO2-NPs. The strongest and broadened peak of anatase was observed at the frequency of 641.58 cm-1. The metabolic activity of P. aeruginosa exposed to the MIC of TiO2-NPs was measured based on the reduction of tetrazolium salt by the dehydrogenase enzyme, produced by the metabolically active bacterial cells. The reduction in TTC was evident from the appearance of a red colored formazan in the solution. A noticeable suppression in the cell viability by 30.76 ±â€¯3.96% of P. aeruginosa in the biofilm mode was found in presence of TiO2-NPs. Furthermore, the Minimum Inhibitory Concentration (MIC) of TiO2-NPs exhibited profound antibiofilm activity against P. aeruginosa by effectively preventing the adherence of the planktonic cells to the substratum. Thus, these NPs may be employed in controlling bacterial infections associated with biofilm.


Assuntos
Aloe/química , Biofilmes/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Pseudomonas aeruginosa/fisiologia , Titânio/química , Aloe/metabolismo , Química Verde , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Extratos Vegetais/química , Folhas de Planta/química , Folhas de Planta/metabolismo
11.
J Photochem Photobiol B ; 201: 111637, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31706086

RESUMO

Plants are considered to be a leading source for possible human therapeutic agents. This holistic study has investigated the anti-quorum sensing (anti-QS), anti-infection, antioxidant and anti-photoaging properties of neglected plant Diplocyclos palmatus. The results showed that D. palmatus methanolic leaf extract (DPME) effectively inhibited the quorum sensing (QS) regulated virulence factor production as well as biofilm formation in Serratia marcescens. The transcriptomic analysis revealed that DPME significantly downed the expression of QS-regulated genes such as fimA, fimC, flhC, bsmB, pigP and shlA in S. marcescens, which supports the outcome of in vitro bioassays. Further, the docking study revealed that the presence of active compounds, namely tocopherols and phytol, DPME exhibited its anti-QS activity against S. marcescens. In addition, DPME treatment extended the lifespan of S. marcescens infected C. elegans by the action of dropping the internal accumulation. Further, qPCR analysis clearly revealed that DPME treatment significantly up-regulated the expression of the lifespan-related gene (daf-16) and immune-related genes (clec-60, clec-87, lys-7 and bec-1) in S. marcescens infected C.elegans. On the other hand, DPME extensively reduced the UV-A induced ROS stress, thereby, extended the lifespan in UV-A photoaged C. elegans. Further, the qPCR analysis also confirmed the up-regulation of daf-16, clec-60, clec-87 and col-19 genes which advocated the improvement of the lifespan, healthspan and collagen production in UV-A photoaged C. elegans. Further bioassays evidenced that that the lifespan extension of photoaged C. elegans was accomplished by the actions of antioxidants such as tocopherols and phytol in DPME.


Assuntos
Envelhecimento/efeitos dos fármacos , Caenorhabditis elegans/efeitos da radiação , Cucurbitaceae/química , Extratos Vegetais/farmacologia , Percepção de Quorum/efeitos dos fármacos , Serratia marcescens/fisiologia , Raios Ultravioleta , Envelhecimento/efeitos da radiação , Animais , Antioxidantes/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes/efeitos dos fármacos , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/fisiologia , Colágeno/metabolismo , Cucurbitaceae/metabolismo , Longevidade/efeitos dos fármacos , Extratos Vegetais/química , Folhas de Planta/química , Folhas de Planta/metabolismo , Infecções por Serratia/patologia , Infecções por Serratia/veterinária , Regulação para Cima/efeitos dos fármacos
12.
Georgian Med News ; (294): 132-136, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31687965

RESUMO

The work is dedicated to the study of biofilms formation process by main pyelonephritis causative agents in children in vitro using methods of light, fluorescent and scanning microscopy. To study biofilms formation bacteria were cultivated in liquid substratum on glass in polystyrene Petri dishes d=40mm. The study demonstrated that all isolates formed biofilms. Adhesion of bacteria planktonic forms took place on the first stage, intracellular matrix formation took place on the second stage, and biofilms formation took place on the third stage. During the study of E. coli and Proteus sрр bacteria preparations with the use of scanning and light microscopy ordered bacteria arrangement was seen in the form of separate structures or tiny clusters of bacterial cells united by matrix. During the study of the ability to form P. aeruginosa isolates biofilms with the help of scanning microscopy it was stated that the adhesion of separate bacterial cells occurs by conglomerates formation surrounded by matrix with further biofilms formation. Bacterial cells in the form of dense elongated sticks were seen under the film. P. аeruginosa isolates daily biofilms were stated to have dense structure in the form of gel. Packed biofilms areas with cells clusters with good fluorescence were found with the help of fluorescent microscopy. During daily K.рneumoniae isolates biofilms study by methods of scanning and fluorescent microscopy it was found that K.рneumoniae biofilms were covered with dense matrix and riddled with multiple canals in the form of apertures. During morphological peculiarities study of E. faecalis isolates biofilms formation with the use of scanning and fluorescent microscopy it was found that bacterial cells were densely packed and united by intracellular matrix under which bacteria of spherical shape were seen. Thus biofilms, the nature of which depends on the type of bacteria, are formed on the surface of conglomerates consisting of bacterial cells. Peculiarities of course and appearance of pyelonephritis chronic form and relapses in children is explained by biofilms formation.


Assuntos
Biofilmes/crescimento & desenvolvimento , Escherichia coli/fisiologia , Pseudomonas aeruginosa/fisiologia , Pielonefrite/microbiologia , Bactérias , Criança , Humanos , Pielonefrite/complicações , Pielonefrite/patologia , Pielonefrite/urina
13.
Adv Exp Med Biol ; 1197: 27-43, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31732932

RESUMO

The supra- and subgingival plaque biofilm communities of plaque are composed of hundreds of different microbes. These communities are spatially and temporally structured, largely due to cell-cell communications that coordinate synergistic interactions, and intracellular signaling systems to sense changes in the surrounding environment. Homeostasis is maintained through metabolic communication, mutualistic cross-feeding, and cross-respiration. These nutritional symbioses can reciprocally influence the local microenvironments by altering the pH and by detoxifying oxidative compounds. Signal transduction mechanisms include two-component systems, tyrosine phosphorelays, quorum sensing systems, and cyclic nucleotide secondary messengers. Signaling converges on transcriptional programs and can result in synergistic or antagonistic interbacterial interactions that sculpt community development. The sum of all these interactions can be a well-organized polymicrobial community that remains in homeostasis with the host, or a dysbiotic community that provokes pathogenic responses in the host.


Assuntos
Fenômenos Fisiológicos Bacterianos , Biofilmes , Mucosa Bucal , Transdução de Sinais , Mucosa Bucal/microbiologia , Percepção de Quorum , Simbiose
14.
Adv Exp Med Biol ; 1197: 119-141, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31732939

RESUMO

Oral cavity harbors a complex and highly diverse microbial community. Cross-kingdom interactions between Candida and oral bacteria are critical for their co-existence, which may also affect the course and the severity of biofilm-mediated bacterial-mediated diseases. C. albicans has been found in polymicrobial biofilms associated with denture stomatitis, oral mucositis, dental caries, periodontal diseases, peri-implantitis, and root canal infection. Thus, it is of utmost importance to unravel the mechanisms of Candida-bacterial interactions and their impact on the onset and severity of cross-kingdom biofilm-related diseases. Here, we highlight the potential role of Candida-bacterial biofilm interactions in the pathogenesis of oral diseases, especially mucosal infections and dental caries. The influence of Candida-bacterial biofilms on the mucosal host immune response is also discussed. Finally, we present some of the current and prospective therapeutic strategies for controlling these cross-kingdom interactions and their virulence properties associated with oral diseases.


Assuntos
Fenômenos Fisiológicos Bacterianos , Biofilmes , Candida , Interações Hospedeiro-Patógeno , Doenças da Boca , Candida/fisiologia , Candida albicans/fisiologia , Humanos , Doenças da Boca/microbiologia , Estudos Prospectivos
15.
Oecologia ; 191(4): 957-970, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31690999

RESUMO

The relative importance of stochastic- and niche-based processes shifts during successional time and across different types of habitats. Microbial biofilms are known to undergo such successional shifts. However, little is known about the interaction between these successional trajectories and habitat filters. Harsh habitat filters could affect biofilm successional trajectories by strengthening niche-based processes and weakening stochastic processes. We used mesocosms to track successional trajectories in bacterial communities associated with the striped shore crab (Pachygrapsus transversus). We followed replicated microbial communities under strong and weak habitat filters associated with the crab's gut and carapace. For bacteria, colonization of the crab's gut is constrained by strong chemical and physical filtering, while the carapace remains relatively open for colonization. Consistent with successional models of bacterial biofilms, carapace microbial communities initially converged in community composition at day 8 and diverged thereafter. We expected gut microbial communities to deviate from the trajectory in the carapace and converge towards a subset of tolerant species. Instead, bacterial communities in the gut exhibited low richness, unchanging similarity in composition and turnover in species identities throughout the duration of our study. These habitat filter effects were linked with weak species interactions and low influence from colonization in the gut. If these findings are representative of differences in filter strength in a continuum of successional trajectories, habitat filters may provide basis for predictions that link successional models and habitat types.


Assuntos
Braquiúros , Microbiota , Animais , Bactérias , Biofilmes , Ecossistema , Processos Estocásticos
16.
Am J Dent ; 32(5): 245-250, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31675193

RESUMO

PURPOSE: To compare the efficacy of toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler particles to that of conventional sodium fluoride (NaF) toothpaste for the prevention of dentin demineralization and biofilm regrowth. METHODS: Bovine root dentin specimens and glass coverslips were used as biofilm growth substrates. To establish biofilms, glass and dentin specimens were incubated for 72 hours in 0.2% sucrose McBain medium inoculated with stimulated saliva from a single donor. Specimens then received a single 5-minute treatment with S-PRG toothpaste, fluoride toothpaste, or sterilized deionized water and were incubated in McBain medium for 120 hours to allow biofilm regrowth. Output parameters during regrowth (72-192 hours) were pH of spent medium, colony-forming unit (CFU) counts of biofilms, and dentin mineral profiles, integrated mineral loss (IML: vol% × µm), and lesion depth (Ld). Treatment group differences were tested by one-way ANOVA followed by Tukey's multiple range test (P< 0.05). RESULTS: At 144 hours, medium pH was significantly higher in the S-PRG-treated dentin group than in the NaF-treated dentin group. In addition, at 192 hours, the CFU count, IML, and Ld were lower in the S-PRG-treated dentin group than in the NaF-treated dentin group. There were significant differences of pH among dentin groups at 72 hours. Treatment with S-PRG toothpaste markedly inhibited dentin demineralization compared to that with NaF toothpaste. CLINICAL SIGNIFICANCE: Toothpaste containing multiple ions-releasing filler suppressed bacterial viability and inhibited dentin demineralization.


Assuntos
Desmineralização do Dente , Cremes Dentais , Animais , Biofilmes , Bovinos , Dentina , Fluoretos
17.
Chem Commun (Camb) ; 55(87): 13104-13107, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31612170

RESUMO

We designed a few polymyxin derivatives which exhibit broad-spectrum antimicrobial activity. Lead compound P1 could disrupt bacterial membranes rapidly without developing resistance, inhibit biofilms formed by E. coli, and exhibit excellent in vivo activity in an MRSA-infected thigh burden mouse model.


Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Polimixinas/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Biofilmes/efeitos dos fármacos , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Conformação Molecular , Polimixinas/síntese química , Polimixinas/química
18.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 50(3): 339-343, 2019 May.
Artigo em Chinês | MEDLINE | ID: mdl-31631600

RESUMO

Objective: To evaluate the sterilization effect of new designed atmospheric low temperature plasma jet on Candida albicans ( C. albicans) biofilm. Methods: C. albicans was grown into the logarithmic phase, and then was added to polystyrene 24-well microtitre plate. The amount of germs were calculated by viable plate counting to determine the reproducibility of each biofilm well. The germs in biofilm were treated by plasma for different exposure time and then the survived germs were quantified by plate counting, the dead cells were determined by staining the biofilm with propidium iodide (PI), and the ultrastructural changes of the germs in biofilm were observed by transmission electron microscopy (TEM). Results: When incubated for 72 h, germs tightly polymerized and classical mature biofilm were formed. This atmospheric low temperature plasma jet could inactivate C. albicans biofilm within a short exposure time. C. albicans were 90% inactivated when treated 20 s and 55 s of plasma treatment reduced bacteria populations to undetectable levels. With the increase of treatment time, enlarged fluorescent positive area appeared, and more bacteria died with the extending of exposure. The TEM scanning results showed that the new plasma jet inactivated C. albicans biofilm mainly via disrupting cell envelopes and then leading the release of cellular components, thus resulting in loss of cell viability. Conclusion: Plasma generated from atmospheric low temperature plasma jet could damage the cell structure of C. albicans and efficiently sterilize C. albicans biofilm.


Assuntos
Biofilmes , Candida albicans/efeitos dos fármacos , Gases em Plasma/farmacologia , Esterilização , Temperatura Baixa , Reprodutibilidade dos Testes
19.
Braz Oral Res ; 33(suppl 1): e064, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31576948

RESUMO

The aim was of this study was to determine the current weight of evidence for the existence of specific differences between the microbiota of healthy teeth and healthy implants, or of teeth with periodontitis and implants with peri-implantitis. A systematic review was conducted according to the PRISMA statement. The MEDLINE, EMBASE and Cochrane databases were searched up to February 2018 for studies comparing microbiological data of biofilm samples collected from healthy teeth and implants or from teeth with periodontitis and implants with peri-implantitis. The weight of evidence was defined in three categories (strong, moderate and mild/some), according to the difference in number of studies showing statistically significantly higher counts and/or proportions and/or abundance and/or prevalence of microorganisms in health or in disease. Of the 132 articles identified, 8 were included. A wide range of microorganisms were present in different conditions but no microorganisms showed strong, moderate or mild/some evidence for a specific association with either teeth or implants. The results of this systematic review indicated that there is insufficient evidence in the literature to support specific differences between microorganisms colonizing teeth and implants, either in health or in disease.


Assuntos
Implantes Dentários/microbiologia , Gengiva/microbiologia , Peri-Implantite/microbiologia , Periodontite/microbiologia , Bactérias/isolamento & purificação , Biofilmes/crescimento & desenvolvimento , Estudos de Casos e Controles , Placa Dentária/microbiologia , Humanos , Microbiota
20.
Braz Oral Res ; 33(suppl 1): e065, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31576949

RESUMO

Additive manufacturing (AM) is an emerging process for biomaterials and medical devices. Direct Laser Metal Sintering (DLMS) is an AM technique used to fabricate Ti-6Al-4V implant materials with enhanced surface-related properties compared with wrought samples; thus, this technique could influence microbial adsorption and colonization. Therefore, this in vitro study was conducted to evaluate the impact of different implant production processes on microbial adhesion of periodontal pathogens. Titanium discs produced using two different processes-conventional and AM-were divided into three groups: conventional titanium discs with machined surface (G1), AM titanium discs with chemical treatment (G2) and AM titanium discs without chemical treatment (G3). Subgingival biofilm composed of 32 species was formed on the titanium discs, and positioned vertically in 96-well plates, for 7 days. The proportions of microbial complexes and the microbial profiles were analyzed using a DNA-DNA hybridization technique, and data were evaluated using Kruskal-Wallis and Dunnett tests (p < 0.05). Lower proportions of the red complex species were observed in the biofilm formed in G2 compared with that in G1 (p < 0.05). Moreover, the proportions of the microbial complexes were similar between G2 and G3 (p > 0.05). Compared with G1, G2 showed reduced levels of Porphyromonas gingvalis , Actinomyces gerencseriae, and Streptococcus intermedius , and increased levels of Parvimonas micra , Actinomyces odontolyticus, and Eikenella corrodens (p < 0.05). The microbial profile of G3 did not differ from G1 and G2 (p > 0.05). The results of this in vitro study showed that titanium discs produced via AM could alter the microbial profile of the biofilm formed around them. Further clinical studies should be conducted to confirm these findings.


Assuntos
Biofilmes/crescimento & desenvolvimento , Titânio/química , Titânio/farmacologia , Análise de Variância , Bactérias/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Sondas de DNA , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Propriedades de Superfície , Fatores de Tempo
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