Efficacy of taurolidine against periodontopathic species—an in vitro study

The antimicrobial effect of taurolidine was tested against periodontopathic species in comparison to chlorhexidine digluconate in the presence or absence of serum. Minimal inhibitory concentrations (MIC), microbiocidal concentrations (MBC), as well as killing were determined against 32 different microbial strains including 3 Porphyromonas gingivalis, 3 Aggregatibacter actinomycetemcomitans, and 15 potentially superinfecting species with and without 25% v/v human serum. The MIC50 of taurolidine against the tested microbial strains was 0.025% and the MIC90 0.05%. The respective values for the MBCs were 0.05% and 0.1%. Addition of 25% serum (heat-inactivated) did not change the MIC and MBC values of taurolidine. In contrast, MICs and MBCs of chlorhexidine (CHX) increased by two steps after addition of serum. Taurolidine killed microorganisms in a concentration and time-dependent manner, the killing rate of 1.6% taurolidine was 99.08% ± 2.27% in mean after 2h. Again, killing activity of taurolidine was not affected if serum was added, whereas addition of inactivated serum clearly reduced the killing rate of all selected bacterial strains by CHX. Therefore, taurolidine possesses antimicrobial properties which are not reduced in the presence of serum as a main component in gingival crevicular fluid and wound fluid. Taurolidine may have potential as an antimicrobial agent in non-surgical and surgical periodontal treatmen

Ultrastructure of the Membrana Limitans Interna after Dye-Assisted Membrane Peeling

The purpose of this study was to investigate the ultrastructure of the membrana limitans interna (internal limiting membrane, ILM) and to evaluate alterations to the retinal cell layers after membrane peeling with vital dyes. Twenty-five patients (25 eyes) who underwent macular hole surgery were included, whereby 12 indocyanine green (ICG)- and 13 brilliant blue G (BBG)-stained ILM were analyzed using light, transmission electron and scanning electron microscopy. Retinal cell fragments on the ILM were identified in both groups using immunohistochemistry. Comparing ICG- and BBG-stained membranes, larger cellular fragments were observed at a higher frequency in the BBG group. Thereby, the findings indicate that ICG permits an enhanced separation of the ILM from the underlying retina with less mechanical destruction. A possible explanation might be seen in the known photosensitivity of ICG, which induces a stiffening and shrinkage of the ILM but also generates retinal toxic metabolite

Micromonospora schwarzwaldensis sp. nov., a producer of telomycin, isolated from soil

A Gram-positive, spore-forming actinomycete strain (HKI0641T) was isolated from a soil sample collected in the Black Forest, Germany. During a screening for antimicrobial natural products this bacterium was identified as a producer of the antibiotic telomycin. Morphological characteristics and chemotaxonomic data suggested that the strain belongs to the genus Micromonospora. The peptidoglycan contains meso-diaminopimelic acid, and the fatty acid profile consists predominantly of anteiso-C15:0, iso-C15:0, iso-C16:0 and C16:0. MK-10(H4), MK-10(H2) and MK-10 were identified as the major menaquinones. To determine the taxonomic positioning of strain HKI0641T, we computed a binary tanglegram of two rooted phylogenetic trees that were based upon 16S rRNA and gyrB gene sequences, respectively. The comparative analysis of the two common classification methods strongly supported the phylogenetic affiliation with the genus Micromonospora, but it also revealed discrepancies in the assignment at the level of the genomic species. 16S rRNA gene sequence analysis identified M. coxensis DSM 45161T (99.1%) and M. marina DSM 45555T (99.0%) as the nearest taxonomic neighbours, whereas the gyrB sequence of strain HKI0641T indicated a closer relationship to M. aurantiaca DSM 43813T (95.1%). By means of DNA-DNA hybridization experiments, it was possible to resolve this issue and to clearly differentiate strain HKI0641T from other Micromonospora species. The type strains of the aforementioned Micromonospora species could be further distinguished from strain HKI0641T by several phenotypic properties, such as colony colour, NaCl tolerance and the utilization of carbon sources. The isolate was therefore assigned to a new species, for which the name Micromonospora schwarzwaldensis sp. nov. is proposed. The type strain is HKI0641T (= DSM 45708T = CIP 110415T).Fil: Vela Gurovic, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Hans-Knöll-Institute; AlemaniaFil: Müller, Sebastian. Hans-Knöll-Institute; AlemaniaFil: Domin, Nicole. Hans-Knöll-Institute; AlemaniaFil: Seccareccia, Ivana. Hans-Knöll-Institute; AlemaniaFil: Nietzsche, Sandor. University Hospital Jena; AlemaniaFil: Martin, Karin. Hans-Knöll-Institute; AlemaniaFil: Nett, Markus. Hans-Knöll-Institute; Alemani

Salt and Metal Tolerance Involves Formation of Guttation Droplets in Species of the Aspergillus versicolor Complex

Three strains of the Aspergillus versicolor complex were isolated from a salty marsh at a former uranium mining site in Thuringia, Germany. The strains from a metal-rich environment were not only highly salt tolerant (up to 20% NaCl), but at the same time could sustain elevated Cs and Sr (both up to 100 mM) concentrations as well as other (heavy) metals present in the environment. During growth experiments when screening for differential cell morphology, the occurrence of guttation droplets was observed, specifically when elevated Sr concentrations of 25 mM were present in the media. To analyze the potential of metal tolerance being promoted by these excretions, proteomics and metabolomics of guttation droplets were performed. Indeed, proteins involved in up-regulated metabolic activities as well as in stress responses were identified. The metabolome verified the presence of amino sugars, glucose homeostasis-regulating substances, abscisic acid and bioactive alkaloids, flavones and quinones

Remineralization of Artificially Demineralized Human Enamel and Dentin Samples by Zinc-Carbonate Hydroxyapatite Nanocrystals

(1) Background: Decalcified enamel and dentin surfaces can be regenerated with non-fluoride-containing biomimetic systems. This study aimed to investigate the effect of a zinc carbonate-hydroxyapatite-containing dentifrice on artificially demineralized enamel and dentin surfaces. (2) Methods: Human enamel and dentin discs were prepared and subjected to surface demineralization with 30% orthophosphoric acid for 60 s. Subsequently, in the test group (n = 20), the discs were treated three times a day for 3 min with a zinc carbonate-hydroxyapatite-containing toothpaste (biorepair®). Afterwards, all samples were gently rinsed with PBS (5 s) and stored in artificial saliva until next use. Samples from the control group (n = 20) received no dentifrice-treatment and were stored in artificial saliva, exclusively. After 15 days of daily treatment, specimens were subjected to Raman spectroscopy, energy-dispersive X-ray micro-analysis (EDX), white-light interferometry, and profilometry. (3) Results: Raman spectroscopy and white-light interferometry revealed no significant differences compared to the untreated controls. EDX analysis showed calcium phosphate and silicon dioxide precipitations on treated dentin samples. In addition, treated dentin surfaces showed significant reduced roughness values. (4) Conclusions: Treatment with biorepair® did not affect enamel surfaces as proposed. Minor mineral precipitation and a reduction in surface roughness were detected among dentin surfaces only

Long-Chain and Very Long-Chain Ceramides Mediate Doxorubicin-Induced Toxicity and Fibrosis

Doxorubicin (Dox) is a chemotherapeutic agent with cardiotoxicity associated with profibrotic effects. Dox increases ceramide levels with pro-inflammatory effects, cell death, and fibrosis. The purpose of our study was to identify the underlying ceramide signaling pathways. We aimed to characterize the downstream effects on cell survival, metabolism, and fibrosis. Human fibroblasts (hFSF) were treated with 0.7 µM of Dox or transgenically overexpressed ceramide synthase 2 (FLAG-CerS2). Furthermore, cells were pre-treated with MitoTempo (MT) (2 h, 20 µM) or Fumonisin B1 (FuB) (4 h, 100 µM). Protein expression was measured by Western blot or immunofluorescence (IF). Ceramide levels were determined with mass spectroscopy (MS). Visualizations were conducted using laser scanning microscopy (LSM) or electron microscopy. Mitochondrial activity was measured using seahorse analysis. Dox and CerS2 overexpression increased CerS2 protein expression. Coherently, ceramides were elevated with the highest peak for C24:0. Ceramide- induced mitochondrial ROS production was reduced with MT or FuB preincubation. Mitochondrial homeostasis was reduced and accompanied by reduced ATP production. Our data show that the increase in pro-inflammatory ceramides is an essential contributor to Dox side-effects. The accumulation of ceramides resulted in a lipotoxic shift and subsequently mitochondrial structural and functional damage, which was partially reversible following inhibition of ceramide synthesis

A Biofilm Pocket Model to Evaluate Different Non-Surgical Periodontal Treatment Modalities in Terms of Biofilm Removal and Reformation, Surface Alterations and Attachment of Periodontal Ligament Fibroblasts.

BACKGROUND AND AIM There is a lack of suitable in vitro models to evaluate various treatment modalities intending to remove subgingival bacterial biofilm. Consequently, the aims of this in vitro-study were: a) to establish a pocket model enabling mechanical removal of biofilm and b) to evaluate repeated non-surgical periodontal treatment with respect to biofilm removal and reformation, surface alterations, tooth hard-substance-loss, and attachment of periodontal ligament (PDL) fibroblasts. MATERIAL AND METHODS Standardized human dentin specimens were colonized by multi-species biofilms for 3.5 days and subsequently placed into artificially created pockets. Non-surgical periodontal treatment was performed as follows: a) hand-instrumentation with curettes (CUR), b) ultrasonication (US), c) subgingival air-polishing using erythritol (EAP) and d) subgingival air-polishing using erythritol combined with chlorhexidine digluconate (EAP-CHX). The reduction and recolonization of bacterial counts, surface roughness (Ra and Rz), the caused tooth substance-loss (thickness) as well as the attachment of PDL fibroblasts were evaluated and statistically analyzed by means of ANOVA with Post-Hoc LSD. RESULTS After 5 treatments, bacterial reduction in biofilms was highest when applying EAP-CHX (4 log10). The lowest reduction was found after CUR (2 log10). Additionally, substance-loss was the highest when using CUR (128±40 µm) in comparison with US (14±12 µm), EAP (6±7 µm) and EAP-CHX (11±10) µm). Surface was roughened when using CUR and US. Surfaces exposed to US and to EAP attracted the highest numbers of PDL fibroblasts. CONCLUSION The established biofilm model simulating a periodontal pocket combined with interchangeable placements of test specimens with multi-species biofilms enables the evaluation of different non-surgical treatment modalities on biofilm removal and surface alterations. Compared to hand instrumentation the application of ultrasonication and of air-polishing with erythritol prevents from substance-loss and results in a smooth surface with nearly no residual biofilm that promotes the reattachment of PDL fibroblasts

The impact of episporic modification of Lichtheimia corymbifera on virulence and interaction with phagocytes

Fungal infections caused by the ancient lineage Mucorales are emerging and increasingly reported in humans. Comprehensive surveys on promising attributes from a multitude of possible virulence factors are limited and so far, focused on Mucor and Rhizopus. This study addresses a systematic approach to monitor phagocytosis after physical and enzymatic modification of the outer spore wall of Lichtheimia corymbifera, one of the major causative agents of mucormycosis. Episporic modifications were performed and their consequences on phagocytosis, intracellular survival and virulence by murine alveolar macrophages and in an invertebrate infection model were elucidated. While depletion of lipids did not affect the phagocytosis of both strains, delipidation led to attenuation of LCA strain but appears to be dispensable for infection with LCV strain in the settings used in this study. Combined glucano-proteolytic treatment was necessary to achieve a significant decrease of virulence of the LCV strain in Galleria mellonella during maintenance of the full potential for spore germination as shown by a novel automated germination assay. Proteolytic and glucanolytic treatments largely increased phagocytosis compared to alive resting and swollen spores. Whilst resting spores barely (1-2%) fuse to lysosomes after invagination in to phagosomes, spore trypsinization led to a 10-fold increase of phagolysosomal fusion as measured by intracellular acidification. This is the first report of a polyphasic measurement of the consequences of episporic modification of a mucormycotic pathogen in spore germination, spore surface ultrastructure, phagocytosis, stimulation of Toll-like receptors (TLRs), phagolysosomal fusion and intracellular acidification, apoptosis, generation of reactive oxygen species (ROS) and virulence

Nanocellulose as a natural source for groundbreaking applications in materials science: Todays state

Nanocelluloses are natural materials with at least one dimension in the nano-scale. They combine important cellulose properties with the features of nanomaterials and open new horizons for materials science and its applications. The field of nanocellulose materials is subdivided into three domains: biotechnologically produced bacterial nanocellulose hydrogels, mechanically delaminated cellulose nanofibers, and hydrolytically extracted cellulose nanocrystals. This review article describes todays state regarding the production, structural details, physicochemical properties, and innovative applications of these nanocelluloses. Promising technical applications including gels/foams, thickeners/stabilizers as well as reinforcing agents have been proposed and research from last five years indicates new potential for groundbreaking innovations in the areas of cosmetic products, wound dressings, drug carriers, medical implants, tissue engineering, food and composites. The current state of worldwide commercialization and the challenge of reducing nanocellulose production costs are also discussed.Dana Kralisch and Dagmar Fischer gratefully acknowledge the Free State of Thuringia and the European Social Fund (2016 FGR 0045) for funding. Dagmar Fischer would like to thank Yvette Pötzinger and Berit Karl for the excellent editorial support. Dieter Klemm, Friederike Kramer and Katrin Petzold-Welcke are grateful for the support by the Federal Ministry of Economic Affairs and Energy, ZIM (KF2748903MF4 and KF2386003MF3). Thanks are due to the employees of Jenpolymer Materials Ltd. & Co. KG and the Polymet Jena Association, especially Priv.-Doz. Dr. Wolfgang Fried, and Prof. Dr. Raimund W. Kinne, Experimental Rheumatology Unit, Department of Orthopedics, Jena University Hospital, Germany as well as to Dr. Detlef Gorski and Elke Langhammer, SuraChemicals GmbH, Jena, Germany for effective and helpful cooperation and stimulating interaction. Dieter Klemm and Friederike Kramer would like to thank Katharina Horn for the excellent editorial support. Miguel Gama acknowledges the funding from QREN (“Quadro de Referência Estratégica Nacional”) through the BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020-Programa Operacional Regional do Norte. Tom Lindström acknowledges RISE Bioeconomy for support and permission to publish. Emily Cranston and Stephanie Kedzior are thankful for funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) in the form of a Discovery Grant (RGPIN 402329) and PGSD graduate student scholarship, as well as support from the Faculty of Engineering at McMaster University.info:eu-repo/semantics/publishedVersio

Production of Extracellular Traps against Aspergillus fumigatus In Vitro and in Infected Lung Tissue Is Dependent on Invading Neutrophils and Influenced by Hydrophobin RodA

Aspergillus fumigatus is the most important airborne fungal pathogen causing life-threatening infections in immunocompromised patients. Macrophages and neutrophils are known to kill conidia, whereas hyphae are killed mainly by neutrophils. Since hyphae are too large to be engulfed, neutrophils possess an array of extracellular killing mechanisms including the formation of neutrophil extracellular traps (NETs) consisting of nuclear DNA decorated with fungicidal proteins. However, until now NET formation in response to A. fumigatus has only been demonstrated in vitro, the importance of neutrophils for their production in vivo is unclear and the molecular mechanisms of the fungus to defend against NET formation are unknown. Here, we show that human neutrophils produce NETs in vitro when encountering A. fumigatus. In time-lapse movies NET production was a highly dynamic process which, however, was only exhibited by a sub-population of cells. NETosis was maximal against hyphae, but reduced against resting and swollen conidia. In a newly developed mouse model we could then demonstrate the existence and measure the kinetics of NET formation in vivo by 2-photon microscopy of Aspergillus-infected lungs. We also observed the enormous dynamics of neutrophils within the lung and their ability to interact with and phagocytose fungal elements in situ. Furthermore, systemic neutrophil depletion in mice almost completely inhibited NET formation in lungs, thus directly linking the immigration of neutrophils with NET formation in vivo. By using fungal mutants and purified proteins we demonstrate that hydrophobin RodA, a surface protein making conidia immunologically inert, led to reduced NET formation of neutrophils encountering Aspergillus fungal elements. NET-dependent killing of Aspergillus-hyphae could be demonstrated at later time-points, but was only moderate. Thus, these data establish that NET formation occurs in vivo during host defence against A. fumigatus, but suggest that it does not play a major role in killing this fungus. Instead, NETs may have a fungistatic effect and may prevent further spreading