Differential microbial colonization on microplastic in the Mediterranean Sea coastal zone

2020 ◽  
Author(s):  
Annika Vaksmaa ◽  
Katrin Knittel ◽  
Alejandro Abdala Asbun ◽  
Maaike Goudriaan ◽  
Andreas Ellrott ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Laser Scanning ◽  
Mesh Size ◽  
Laser Scanning Microscopy ◽  
Microbial Colonization ◽  
Confocal Laser ◽  
Rrna Gene ◽  
Plastic Debris ◽  
Significant Difference ◽  
The Mediterranean

<p>Ocean plastic debris poses a large threat to the marine environment. Millions of tons of plastic end up in the ocean each year and the Mediterranean Sea is one of the most plastic polluted sea. Ocean plastic particles are typically covered with microbial biofilms, but it remains unclear if different polymer types are colonized by different communities. Knowledge in this aspect strengthens our understanding if microbes purely use plastic debris as attachment surface or if they may even contribute to the degradation of plastic. To gain a better understanding of the composition and structure of biofilms on micro plastic particles (MP) in the Mediterranean Sea, we analyzed microbial community covering floating MP in a bay/marina (Marina di Campo) on the island of Elba. MPs were collected with a plankton net (mesh size 50µm), fixed for fluorescence microscopy and stored for subsequent DNA extraction, and identification of the polymer with Raman spectroscopy. The particles were mainly comprised of polyethylene (PE), polypropylene (PP) and polystyrene (PS) and were often brittle and with cracks (PE, PP) and showed visual signs of biofouling (PE, PP, PS). Fluorescence in situ hybridization and imaging by high resolution confocal laser scanning microscopy of single MPs revealed high densities of colonization by microbes. 16S rRNA gene amplicon sequencing (Illumina Miseq) revealed higher abundance of archaeal sequences on PS (up to 29% of the reads) in comparison to PE or PP (up to 3% of the reads).  The bacterial community in the biofilms on each of the three plastic types consisted mainly of the orders Flavobacteriales, Rickettsiales, Alteromonadales, Cytophagales, Rhodobacterales and Oceanospirillales. Furthermore, we found significant difference in the community composition of biofilms on PE compared to PP and PS but not between PP and PS. The indicator species on PE were Calditrichales, detected at 10 times higher sequence abundance on PE than on PP and PS, as well as several uncultured orders. This study sheds light on preferential microbial attachment and biofilm formation on microplastic particles, yet it remains to be revealed, whether and which of these may contribute to plastic degradation.</p>

Morphology of Xenodasys (Gastrotricha): the first species from the Mediterranean Sea and the establishment of Chordodasiopsis gen. nov. and Xenodasyidae fam. nov.

2006 ◽  
Vol 86 (5) ◽  
pp. 1005-1015 ◽  
Author(s):  
M.A. Todaro ◽  
L. Guidi ◽  
F. Leasi ◽  
P. Tongiorgi
Keyword(s):  
Electron Microscopy ◽  
Mediterranean Sea ◽  
Laser Scanning ◽  
Taxonomic Revision ◽  
First Record ◽  
Laser Scanning Microscopy ◽  
Actin Binding ◽  
Confocal Laser ◽  
The Mediterranean ◽  
Submarine Cave

During a survey of the Italian marine meiofauna, several specimens of the rare gastrotrich genus Xenodasys were found in a submarine cave along the Ionian coast of Apulia. The finding represents the first record of the genus for the Mediterranean Sea and reinforces the consideration of marine caves as habitats of high naturalistic value. The specimens, analysed using different microscopy techniques, showed a new species, named Xenodasys eknomios. Scanning electron microscopy, unveiling the astonishing morphology of this unusual gastrotrich, indicates that, due to technical artefacts, light microscopy may generate unreal features, which in the past may have led to the misinterpretation of the anatomical traits of these creatures. Transmission electron microscopy indicated that the ‘Seitenfüsschen’, are genuine elements of the adhesive apparatus, in contrast with previous investigation, which attributed an exclusive sensorial function to these organs. Confocal laser scanning microscopy, combined with actin-binding fluorochromes, revealed muscular elements in a region where originally the muscular chordoid organ was reported for gastrotrich species belonging to the genus Chordodasys. A taxonomic revision of the species currently allocated to the genus Xenodasys led to the establishment of Chordodasiopsis gen. nov. to integrate the former Xenodasys (=Chordodasys) antennatus and to the drafting of emended diagnosis of the genus Xenodasys. An overview of the high-rank systematization of these genera is also provided, with the establishment of Xenodasyidae fam. nov. to allocate both Xenodasys and Chordodasiopsis.

Use of confocal laser scanning microscopy and a computer model to understand ink cavitation and filamentation

TAPPI Journal ◽  
2010 ◽  
Vol 9 (10) ◽  
pp. 7-15
Author(s):  
HANNA KOIVULA ◽  
DOUGLAS BOUSFIELD ◽  
MARTTI TOIVAKKA
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Print Quality ◽  
Length Scale ◽  
Offset Printing ◽  
Significant Difference ◽  
Printing Speed

In the offset printing process, ink film splitting has an important impact on formation of ink filaments. The filament size and its distribution influence the leveling of ink and hence affect ink setting and the print quality. However, ink filaments are difficult to image due to their short lifetime and fine length scale. Due to this difficulty, limited work has been reported on the parameters that influence filament size and methods to characterize it. We imaged ink filament remains and quantified some of their characteristics by changing printing speed, ink amount, and fountain solution type. Printed samples were prepared using a laboratory printability tester with varying ink levels and operating settings. Rhodamine B dye was incorporated into fountain solutions to aid in the detection of the filaments. The prints were then imaged with a confocal laser scanning microscope (CLSM) and images were further analyzed for their surface topography. Modeling of the pressure pulses in the printing nip was included to better understand the mechanism of filament formation and the origin of filament length scale. Printing speed and ink amount changed the size distribution of the observed filament remains. There was no significant difference between fountain solutions with or without isopropyl alcohol on the observed patterns of the filament remains.

scholarly journals Micromorphological analysis and bond strength comparison of two adhesives for different degrees of dental fluorosis

2020 ◽  
Author(s):  
Shuangfeng Liu ◽  
Yanxia Zhu ◽  
Tana Gegen
Keyword(s):  
Shear Strength ◽  
Bond Strength ◽  
Bonding Strength ◽  
Laser Scanning ◽  
Dental Fluorosis ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Cohesive Failure ◽  
Bonding System ◽  
Significant Difference

Abstract The objective of this study was to analyze morphologically the all-etching bonding system and self-etching bonding system for enamel with different degrees of fluorosis and evaluate the bond strength of each system. Teeth that were indicated for extraction owing to orthodontic or periodontal problems were selected. According to Dean’s index and the Thylstrup-Fejerskov index, 180 extracted teeth were divided into three groups of mild, moderate, and severe dental fluorosis (DF), with 60 teeth in each group. The teeth in each group were randomly divided into two subgroups (n = 30), which were then subjected to the all-etching bonding system (Prime & Bond NT) and self-etching bonding system (SE-Bond). Each group of adhesives was used to bond Z350 universal resin (3M) to the etched dental enamel. Tensile and shear tests were conducted to determine the bond strength. Subsequently, the fractured specimens were investigated using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The Prime & Bond NT was statistically significant for the tensile and shear strength of enamel with mild fluorosis (P < 0.05) but did not exhibit a significant difference for moderate and severe DF (P > 0.05). The SE-Bond was not statistically significant for the tensile and shear strength of mild, moderate, or severe DF (P > 0.05). The SEM and CLSM results reveal that the mild fluorosis enamel crystals were relatively dense, and a small amount of resin remained. The moderate fluorosis enamel crystals were loosely arranged, and the gaps were widened. The severe fluorosis enamel crystals were irregularly arranged. The disorder was aggravated, and the dentinal orifice was exposed by partial enamel exfoliation. The bonding strength of mild fluorosis enamel with the Prime & Bond NT was better than that with the SE-Bond, and cohesive failure was the most common mode of failure. Because there was no difference in the bonding strength of the SE-Bond for different degrees of DF, we recommend the use of the all-etching adhesive system in the clinical treatment of teeth with mild fluorosis.

scholarly journals In Situ Characterization ofNitrospira-Like Nitrite-Oxidizing Bacteria Active in Wastewater Treatment Plants

2001 ◽  
Vol 67 (11) ◽  
pp. 5273-5284 ◽  
Author(s):  
Holger Daims ◽  
Jeppe L. Nielsen ◽  
Per H. Nielsen ◽  
Karl-Heinz Schleifer ◽  
Michael Wagner
Keyword(s):  
Wastewater Treatment ◽  
16S Rrna ◽  
Laser Scanning ◽  
Wastewater Treatment Plants ◽  
Carbon Sources ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Rrna Gene ◽  
Phylogenetic Affiliation

ABSTRACT Uncultivated Nitrospira-like bacteria in different biofilm and activated-sludge samples were investigated by cultivation-independent molecular approaches. Initially, the phylogenetic affiliation of Nitrospira-like bacteria in a nitrifying biofilm was determined by 16S rRNA gene sequence analysis. Subsequently, a phylogenetic consensus tree of theNitrospira phylum including all publicly available sequences was constructed. This analysis revealed that the genusNitrospira consists of at least four distinct sublineages. Based on these data, two 16S rRNA-directed oligonucleotide probes specific for the phylum and genus Nitrospira, respectively, were developed and evaluated for suitability for fluorescence in situ hybridization (FISH). The probes were used to investigate the in situ architecture of cell aggregates ofNitrospira-like nitrite oxidizers in wastewater treatment plants by FISH, confocal laser scanning microscopy, and computer-aided three-dimensional visualization. Cavities and a network of cell-free channels inside the Nitrospiramicrocolonies were detected that were water permeable, as demonstrated by fluorescein staining. The uptake of different carbon sources byNitrospira-like bacteria within their natural habitat under different incubation conditions was studied by combined FISH and microautoradiography. Under aerobic conditions, theNitrospira-like bacteria in bioreactor samples took up inorganic carbon (as HCO3 − or as CO2) and pyruvate but not acetate, butyrate, and propionate, suggesting that these bacteria can grow mixotrophically in the presence of pyruvate. In contrast, no uptake by theNitrospira-like bacteria of any of the carbon sources tested was observed under anoxic or anaerobic conditions.

scholarly journals Calcite Biomineralization by Bacterial Isolates from the Recently Discovered Pristine Karstic Herrenberg Cave

2011 ◽  
Vol 78 (4) ◽  
pp. 1157-1167 ◽  
Author(s):  
Anna Rusznyák ◽  
Denise M. Akob ◽  
Sándor Nietzsche ◽  
Karin Eusterhues ◽  
Kai Uwe Totsche ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Extracellular Polymeric Substances ◽  
Large Fraction ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Rrna Gene ◽  
Seepage Water ◽  
Bacterial Cells ◽  
Content Type ◽  
Rich Media

ABSTRACTKarstic caves represent one of the most important subterranean carbon storages on Earth and provide windows into the subsurface. The recent discovery of the Herrenberg Cave, Germany, gave us the opportunity to investigate the diversity and potential role of bacteria in carbonate mineral formation. Calcite was the only mineral observed by Raman spectroscopy to precipitate as stalactites from seepage water. Bacterial cells were found on the surface and interior of stalactites by confocal laser scanning microscopy. Proteobacteria dominated the microbial communities inhabiting stalactites, representing more than 70% of total 16S rRNA gene clones. Proteobacteria formed 22 to 34% of the detected communities in fluvial sediments, and a large fraction of these bacteria were also metabolically active. A total of 9 isolates, belonging to the generaArthrobacter,Flavobacterium,Pseudomonas,Rhodococcus,Serratia, andStenotrophomonas, grew on alkaline carbonate-precipitating medium. Two cultures with the most intense precipitate formation,Arthrobacter sulfonivoransandRhodococcus globerulus, grew as aggregates, produced extracellular polymeric substances (EPS), and formed mixtures of calcite, vaterite, and monohydrocalcite.R. globerulusformed idiomorphous crystals with rhombohedral morphology, whereasA. sulfonivoransformed xenomorphous globular crystals, evidence for taxon-specific crystal morphologies. The results of this study highlighted the importance of combining various techniques in order to understand the geomicrobiology of karstic caves, but further studies are needed to determine whether the mineralogical biosignatures found in nutrient-rich media can also be found in oligotrophic caves.

scholarly journals Evaluation of four final irrigation protocols for cleaning root canal walls

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Qiang Li ◽  
Qian Zhang ◽  
Xiaoying Zou ◽  
Lin Yue
Keyword(s):  
Root Canal ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Smear Layer ◽  
Confocal Laser ◽  
Bacterial Survival ◽  
Bacterial Inhibition ◽  
Layer Removal ◽  
Significant Difference ◽  
Canal Systems

Abstract The aim of this study was to compare the efficiency of four final irrigation protocols in smear layer removal and bacterial inhibition in root canal systems. Thirty roots inoculated with Enterococcus faecalis were prepared with ProTaper Universal files. The teeth were disinfected by conventional needle irrigation, sonic agitation using the EndoActivator device, passive ultrasonic irrigation, or an M3 Max file. Teeth with no root canal preparation served as blank controls for the establishment of the infection baseline. Teeth with preparation but no final irrigation served as a post-instrumentation baseline. After the final irrigation, the teeth were sectioned in half. One half of each tooth was examined by scanning electron microscopy (SEM) to assess smear layer removal using a five-point scale. The other half was examined by confocal laser scanning microscopy (CLSM) using the LIVE/DEAD BackLight bacterial viability kit to evaluate the depth of bacterial survival in dentinal tubules. SEM analysis revealed no significant difference in smear layer removal throughout the whole canal among the EA, PUI, and M3 Max groups (P > 0.05). CLSM revealed that PUI achieved the greatest bacterial inhibition depth in the coronal ((174.27 ± 31.63) μm), middle ((160.94 ± 37.77) μm), and apical ((119.53 ± 28.49) μm) thirds of the canal (all P < 0.05 vs. other groups). According to this comprehensive SEM and CLSM evaluation, PUI appears to have the best infection control ability in root canal systems.

Comparative analysis of cyanobacteria inhabiting rocks with different light transmittance in the Mojave Desert: a Mars terrestrial analogue

2014 ◽  
Vol 13 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Heather D. Smith ◽  
Mickael Baqué ◽  
Andrew G. Duncan ◽  
Christopher R. Lloyd ◽  
Christopher P. McKay ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Mojave Desert ◽  
Laser Scanning ◽  
Rock Type ◽  
Red Shift ◽  
Laser Scanning Microscopy ◽  
Light Transmittance ◽  
Confocal Laser ◽  
Rrna Gene ◽  
Rock Types

AbstractThe Mojave Desert has been long considered a suitable terrestrial analogue to Mars in many geological and astrobiological aspects. The Silver Lake region in the Mojave Desert hosts several different rock types (talc, marble, quartz, white carbonate and red-coated carbonate) colonized by hypoliths within a few kilometres. This provides an opportunity to investigate the effect of rock type on hypolithic colonization in a given environment. Transmission measurements from 300 to 800 nm showed that the transmission of blue and UVA varied between rock types. The wavelength at which the transmission fell to 1% of the transmission at 600 nm was 475 nm for white carbonate and quartz, 425 nm for red-coated carbonate and talc and 380 nm for marble. The comparative analysis of the cyanobacterial component of hypoliths under different rocks, as revealed by sequencing 16S rRNA gene clone libraries, showed no significant variation with rock type; hypoliths were dominated by phylotypes of the genusChroococcidiopsis, although less abundant phylotypes of the genusLoriellopsis, LeptolyngbyaandScytonemaoccurred. The comparison of the confocal laser scanning microscopy-λ (CLSM-λ) scan analysis of the spectral emission of the photosynthetic pigments ofChroococcidiopsisin different rocks with the spectrum of isolatedChroococcidiopsissp. 029, revealed a 10 nm red shift in the emission fingerprinting for quartz and carbonate and a 5 nm red shift for talc samples. This result reflects the versatility ofChroococcidiopsisin inhabiting dry niches with different light availability for photosynthesis.

scholarly journals Enhanced Bactericidal Efficacy of NaOCl at pH 12 Followed by Acidified NaOCl at pH 6.5 on Enterococcus faecalis Biofilm

2020 ◽  
Vol 10 (17) ◽  
pp. 6096
Author(s):  
Ronald Wigler ◽  
Shlomo Matalon ◽  
Tomer Goldberger ◽  
Anat Or Lerner ◽  
Anda Kfir
Keyword(s):  
Contact Time ◽  
Laser Scanning ◽  
Saline Solution ◽  
Volume Ratio ◽  
Bactericidal Effect ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Red Fluorescence ◽  
Bactericidal Efficacy ◽  
Significant Difference

This study aimed to determine the bactericidal efficacy of sequential use of NaOCl pH 12 followed by acidified NaOCl pH 6.5, and compare it to that of either of these NaOCl solutions alone. E. faecalis biofilm was grown on standardized dentine specimens for four weeks. The specimens were randomly divided into four groups: (A) 4 min exposure to 0.9% saline solution (control); (B) 4 min exposure to 4% NaOCl pH 12; (C) 4 min exposure to 4% NaOCl pH 6.5; and (D) 2 min exposure to 4% NaOCl pH 12 followed by 2 min exposure to 4% NaOCl pH 6.5. The bactericidal activity was evaluated after the 4 min of contact time using confocal laser scanning microscopy. The volume ratio of red fluorescence to green and red fluorescence indicated the proportion of dead cells in the biofilm. The percent of dead cells in the saline solution group was significantly lower than those in the other groups. There was no significant difference between NaOCl pH 12 compared to NaOCl pH 6.5. The sequential use of NaOCl pH 12 followed by pH 6.5 significantly increased the percent of dead cells compared to both the samples exposed to either NaOCl pH 12 or pH 6.5. These results show that sequential irrigation protocol had a stronger bactericidal effect than the commonly used NaOCl pH 12.

Bacterial Colonization in the Marginal Region of Ceramic Restorations: Effects of Different Cement Removal Methods and Polishing

2016 ◽  
Vol 41 (6) ◽  
pp. 642-654 ◽  
Author(s):  
SMB Pereira ◽  
LC Anami ◽  
CA Pereira ◽  
ROA Souza ◽  
KZ Kantorski ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Bacterial Colonization ◽  
Resin Cement ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Significant Difference ◽  
Ceramic Blocks ◽  
Cement Removal ◽  
Ceramic Restorations ◽  
Marginal Region

SUMMARY This study evaluated the effects of excess cement removal techniques, with or without subsequent polishing, on biofilm formation and micromorphology in the marginal region of the tooth/restoration. From bovine teeth, 96 dentin blocks (4 × 8 × 2 mm) were produced, molded, and reproduced in type IV gypsum, on which 96 pressed ceramic blocks (Vita PM9, Vita Zahnfabrik; 4 × 8 × 2 mm) were produced via the lost wax technique. The dentin blocks and their respective ceramic blocks were cemented with a self-adhesive resin cement (RelyX U200, 3M ESPE), and cement excess was removed from the margin using four different techniques, followed or not by polishing with silicone rubber tips: MBr, removal with microbrush and photoactivation; MBr-Pol, MBr + polishing; Br, removal with brush and photoactivation; Br-Pol, Br + polishing; Photo-Expl, 5 seconds of initial photoactivation, removal with explorer, and final curing; Photo-Expl-Pol, Photo-Expl + polishing; Photo-SB, 5 seconds of initial photoactivation, removal with scalpel, and final curing; and Photo-SB-Pol, Photo-SB + polishing. After 24 hours, the roughness in the marginal region was analyzed using a profilometer (three measurements on each sample). Micromorphological analyses of the region were performed by stereomicroscope and scanning electron microscopy (SEM). Then the samples were contaminated with sucrose broth standardized suspension with Streptococcus mutans, Staphylococcus aureus, and Candida albicans and incubated for a period of 48 hours. The samples were quantitatively analyzed for bacterial adherence in the marginal region by confocal laser scanning microscopy and counting of colony-forming units (CFUs/mL) and qualitatively analyzed using SEM. Roughness data (Ra) were submitted to two-way analysis of variance, Tukey test at a confidence level of 95%, and Student t-tests. CFU, biomass, and biothickness data were analyzed by Kruskal-Wallis, Mann-Whitney, and Dunn tests. The removing technique statistically influenced Ra (MBr, p=0.0019; Br, p=0.002; Photo-Expl, p=0.0262; Photo-SB, p=0.0196) when comparing the polished and unpolished groups. The MBr and MBr-Pol technique differed significantly for CFU/mL values (p=0.010). There was no significant difference in the amounts of biomass and biothickness comparing polished and unpolished groups and when all groups were compared (p&gt;0.05). Different morphological patterns were observed (more regular surface for polished groups). We conclude that margin polishing after cementation of feldspar/pressed ceramic restorations is decisive for achieving smoother surfaces, as the excess cement around the edges can increase the surface roughness in these areas, influencing bacterial adhesion.

scholarly journals Influence of Light-curing Parameters on Biofilm Development and Flexural Strength of a Silorane-based Composite

2016 ◽  
Vol 41 (2) ◽  
pp. 219-227 ◽  
Author(s):  
E Brambilla ◽  
A Ionescu ◽  
G Cazzaniga ◽  
M Ottobelli
Keyword(s):  
Flexural Strength ◽  
Laser Scanning ◽  
Testing Machine ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Curing Time ◽  
Two Samples ◽  
Significant Difference ◽  
Light Curing ◽  
Biofilm Development

SUMMARYObjectives: The aim of this study was to evaluate the differences in biological and mechanical performances of a silorane-based and a methacrylate-based composite. Another aim was to assess the influence of light-curing time and light-curing intensity on in vitro biofilm formation and flexural strength of the two tested composites.Methods: Experiment 1: 432 specimens obtained from a silorane-based composite and from a standard methacrylate-based composite were divided into six groups and light-cured for 10, 20, 30, 40, 60, or 80 seconds, using one of two light-curing intensities, 400 mW/cm2 or 800 mW/cm2. At 24 hours, a monospecific Streptococcus mutans biofilm adherent to the surfaces of the samples was obtained. Then, a colorimetric technique (MTT assay) was used to evaluate the adherent viable biomass. Two samples per group were observed using confocal laser scanning microscopy. Analysis of variance (ANOVA) and Tukey tests were used to analyze the results (p&lt;0.05). Experiment 2: 192 bar-shaped specimens were obtained and light-cured as in the previous experiment. A three-point bend test using a universal testing machine was performed to obtain flexural strength values. ANOVA and Tukey tests were used to analyze the results (p&lt;0.05).Results: In experiment 1, a highly significant difference (p&lt;0.0001) in biofilm development was shown between silorane-based and methacrylate-based composites. In fact, the silorane-based composite exhibited better biological performance. Significant differences were also found between the two light-curing intensities (p&lt;0.018) and for curing times (p&lt;0.0001): silorane-based composite light-cured for 80 seconds at 800 mW/cm2 light-curing intensity showed the lowest biofilm development. In experiment 2, a significant difference in flexural strength (p&lt;0.0318) was only found between the different composites. Nevertheless, both resin composites showed flexural strength values in accordance with International Organization for Standardization guidelines even after 10 seconds of light-curing time.Conclusions: Silorane-based composite was less prone to biofilm development compared with a methacrylate-based composite. Acceptable flexural strength values for both composites were obtained after 10 seconds of light-curing time.

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