Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Wiley (CrossRef)  (30)
Type of Medium
Language
Year
  • 1
    Language: English
    In: Vakuum in Forschung und Praxis, April 2014, Vol.26(2), pp.42-47
    Description: Polymers made of renewable resources increasingly replace conventional plastic materials made of petroleum. Socalled bioplastics can be found e. g. in food industry, for agricultural usage or in the medical field. The range of applications can be further expanded with specialized coating of their surface. Especially in case of food packaging and the usage within medical devices as well as the storage of these composite materials, sterilization or at least the partial reduction of microbial growth is an important issue which needs to be addressed early in the production process. In this work, a commercially available polyhydroxyalkanoate (PHA) pure bioplastic foil of 50 μm thickness was coated with 100 nm of diamond‐like carbon (DLC) and afterwards treated by four different standard methods of sterilization and / or disinfection, namely deep‐freezing, ultraviolet irradiation, autoclaving and immersion in ethanol. The surface morphology of treated DLC‐coated and uncoated samples was investigated and compared to the untreated DLC‐coated and uncoated samples using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Measurements exhibited damage of the composite for autoclaved and in ethanol immersed samples, whereas deep‐frozen and ultraviolet irradiated samples showed no structural changes. These findings clearly demonstrate deep‐freezing and ultraviolet irradiation to be appropriate methods for the disinfection and sterilization, respectively, of the DLC‐coated pure bioplastic foil. DLC‐beschichtete Biokunststoff‐Folie — Auswirkungen verschiedener Sterilisationsmethoden auf die Oberflächenmorphologie Aus erneuerbaren Ressourcen hergestellte Polymere ersetzen zunehmend Erdöl‐basierte konventionelle Kunststoffe. Die sogenannten Biokunststoffe sind z. B. in der Nahrungsmittelindustrie, der Landwirtschaft oder der Medizin zu finden. Ihr Anwendungsspektrum kann durch spezielle Oberflächenbeschichtungen aber noch erweitert werden. Insbesondere in der Nahrungsmittelverpackungsindustrie, bei der Verwendung in medizinischen Apparaturen und Implantaten sowie deren Lagerung ist die Sterilisierung oder zumindest die teilweise Reduzierung der mikrobiellen Aktivität ein wichtiger Aspekt, der bereits frühzeitig im Produktionsprozess berücksichtigt werden muss. In der vorliegenden Arbeit wurde kommerziell erhältliche 50 μm dicke Polyhydroxyalkanoat (PHA)‐Biokunststoff‐Folie mit 100 nm diamant‐ähnlichem Kohlenstoff (DLC) beschichtet und danach mit vier verschiedenen Standardmethoden der Sterilisation und/oder Desinfektion, nämlich UV‐Bestrahlung, Autoklavieren, Tiefkühlung, und Eintauchen in Ethanol, behandelt. Die Oberflächenstruktur der so behandelten Proben (DLC‐beschichtet und unbeschichtet) wurde mittels REM (Rasterelektronenmikroskopie) und AFM (Rasterkraftmikroskopie) untersucht und mit den entsprechenden unbehandelten Proben verglichen. Die Messungen ergaben Beschädigungen des Materialverbundes bei der Behandlung durch Autoklavieren und Ethanol, wohingegen die tiefgekühlten und UV‐bestrahlten Proben keinerlei strukturelle Veränderungen zeigten. Diese Ergebnisse zeigen klar, dass Tiefkühlung und UV‐Bestrahlung geeignete Methoden für die Desinfizierung bzw. Sterilisation dieser DLC‐beschichteten Biokunststoff‐Folien darstellen.
    Keywords: Nahrungsmittelindustrie ; Oberflächenbeschichtung ; Sterilisierung ; Produktionsprozess ; Desinfektion ; Tiefkühlen ; Biokunststoff ; Oberflächenmorphologie ; Polymer ; Kunststoff ; Landwirtschaft ; Polyhydroxyalkanoat ; Diamantähnlicher Kohlenstoff ; Ethanol ; Autoklavierung ; Desinfizieren ; Mikrobenwachstum ; Autoklav ; Immersion ; Strukturumwandlung ; Medizinische Anwendung ; Engineering ; Physics;
    ISSN: 0947-076X
    E-ISSN: 1522-2454
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: Chemical Engineering & Technology, June 2017, Vol.40(6), pp.1107-1114
    Description: Time‐dependent effects on the apparent roughness and surface free energy of different polymeric surfaces and stainless steel were studied during the biofouling process for K12. The surface roughness increases during primary adhesion of on the surfaces and is later reduced as the surface between scattered bacteria is completely covered, forming a uniform biofilm. During the fouling process, the polar fraction of the surface free energy significantly increased, whereas the dispersive fraction decreased for all substrates. The attachment of and subsequent bacterial production of extracellular polymeric substances increased the polarity of the initially nonpolar polymeric surfaces to increase wettability. Surfaces of polymeric heat exchangers show beneficial biofouling tendencies, compared with those of stainless steel, in applications utilizing river water as a coolant. The measurable surface characteristics of the biofilm change drastically over time and have to be considered in fluid simulations. Correlations between initial roughness and wettability are given with respect to biofilm formation.
    Keywords: Adhesion ; Biofouling ; Heat Exchangers ; Polymers ; Surface Properties
    ISSN: 0930-7516
    E-ISSN: 1521-4125
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Journal of Plant Nutrition and Soil Science, October 2017, Vol.180(5), pp.602-613
    Description: Silver nanoparticles (AgNP) are used in a broad range of consumer products and industrial applications. During the regular product life cycle and disposal, AgNP are continuously released into the environment. Hence, the aim of this study was to investigate the potential ecotoxicological effects of AgNP exposure on amoebae. The ATCC 30234 strain and environmental isolate strain C5/2, which are both affiliated with genotype T4, were chosen as representatives of ecologically important soil protozoan organisms. The amoebae were exposed to citrate‐stabilized AgNP (30 and 70 nm in size) for 24 h and 96 h at concentrations ranging from 600 µg L to 20 mg L. A newly adopted cell culture based microscopic assay was applied to assess the adherence ability of the amoeba trophozoites. The general metabolic activity of was determined to be a second independent endpoint by means of intracellular reduction of the redox dye AlamarBlue®. The fate of AgNP within the amoebae and test solutions was visualized by light‐ and transmission electron microscopy (TEM). Both strains showed a significant dose‐dependent decrease of adherence ability ( 〈 0.04) and metabolic activity ( 〈 0.01) after 96 h of AgNP exposure. The environmental strain C5/2 lost both its adherence ability and metabolic activity at lower AgNP concentrations than the type strain, indicating a higher sensitivity to ionic silver. This was confirmed by the application of AgNO, provoking a higher effect level in strain C5/2. AgNP was visualized intracellularly by transmission electron microscopy within the cytoplasm of . This is the first report to show the ecotoxicological effects of short‐term AgNP exposure on the soil protist , causing both changes in the adherence ability and metabolic activity of this amoeba. This combined approach may be a powerful tool in the future for predicting potential harmful ecotoxicological effects of AgNP exposure using soil protozoans.
    Keywords: Acanthamoeba ; Adherence ; Metabolic Activity ; Silver Nanoparticles ; Soil Microbial Food Web ; Top Predator
    ISSN: 1436-8730
    E-ISSN: 1522-2624
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    In: FEMS Microbiology Ecology, 2006, Vol. 56(1), pp.79-94
    Description: The microbial communities of three different habitat types and from two sediment depths in the River Elbe were investigated by fluorescence in situ hybridization at various levels of complexity. Differences in the microbial community composition of free-flowing river water, water within the hyporheic interstitial and sediment-associated bacteria were quantitatively analyzed using domain- and group-specific oligonucleotide probes. Qualitative data on the presence/absence of specific bacterial taxa were gathered using genus- and species-specific probes. The complete data set was statistically processed by univariate statistical approaches, and two-dimensional ordinations of nonmetric multidimensional scaling. The analysis showed: (1) that the resolution of microbial community structures at microenvironments, habitats and locations can be regulated by targeted application of oligonucleotides on phylogenetic levels ranging from domains to species, and (2) that an extensive qualitative presence/absence analysis of multiparallel hybridization assays enables a fine-scale apportionment of spatial differences in microbial community structures that is robust against apparent limitations of fluorescence in situ hybridization such as false positive hybridization signals or inaccessibility of in situ oligonucleotide probes. A general model for the correlation of the phylogenetic depth of focus and the relative spatial resolution of microbial communities by fluorescence in situ hybridization is presented.
    Keywords: Fluorescence Hybridization ; Microbial Communities ; Multivariate Statistics ; Rivers ; Sediments
    ISSN: 01686496
    E-ISSN: 1574-6941
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    In: FEMS Microbiology Ecology, 2008, Vol. 66(2), pp.282-294
    Description: The secretion of extracellular polymeric substances (EPS) by bacteria has been recognized as important across a wide range of scientific disciplines, but in natural sediments, EPS production by microalgae as a mechanism of sediment stabilization has received much more attention than bacterial products. In the present study, the stabilization potential of a natural benthic bacterial assemblage was tested in cultures growing on noncohesive glass beads. The surface erosion resistance as determined by a cohesive strength meter was significantly enhanced over time compared with controls. Nutrient enrichment of the bacterial assemblages by a general broth (bacteria+) resulted in enhanced stabilization (× 3.6) compared with nutrient-depleted (bacteria) assemblages (× 1.8). This correlated with higher bacterial biomass and EPS concentrations in enriched cultures. Substratum stability was closely related to bacterial cell numbers ( R 2 =0.75/0.78) and EPS protein concentrations ( R 2 =0.96/0.53) (for bacteria/bacteria+ treatments, respectively), but not to EPS carbohydrates. This study implies a greater significance of extracellular proteins in substratum cohesion within the EPS complex than recognized previously. The data show both the importance of bacterial assemblages for microbial sediment stabilization and that a change in abiotic conditions can significantly affect sediment stabilization.
    Keywords: Extracellular Polymeric Substances ; Bacterial Engineering ; Sediment Stability ; Sediment Erosion
    ISSN: 01686496
    E-ISSN: 1574-6941
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: International Review of Hydrobiology, July 2001, Vol.86(4‐5), pp.371-381
    Description: Based on computer assisted comparative sequence analysis, the 18S rRNA targeted fungal oligonucleotide probe FUN1429 was designed and evaluated for the identification of metabolically active . The general accessibility of fungal cells for fluorescent oligonucleotides was tested by whole cell hybridizations. Additionally, the influences of different growth media, age of the fungal specimen and the composition of permeability buffers were assessed. All strains showed clear fluorescence hybridization signals after visualization with confocal laser scanning microscopy (CSLM). In contrast fluorescence hybridization signals were hardly detectable by conventional epifluorescence microscopy due to strong fungal autofluorescence. The inherent autofluorescence emitted from the strains increased with the age of cultures, but was significantly decreased by chitinase treatment prior to hybridization. The composition of the growth media showed no measurable effect on signal intensity.
    Keywords: 18s Rrna Targeted Oligonucleotide Probe ; Aquatic Hyphomycetes ; Confocal Laser Scanning Microscopy Clsm ; Fluorescence Hybridization Fish
    ISSN: 1434-2944
    E-ISSN: 1522-2632
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    In: FEMS Microbiology Reviews, December 2000, Vol.24(5), pp.661-671
    Description: Biofilms, accumulations of microorganisms at interfaces, have been described for every aqueous system supporting life. The structure of these microbial communities ranges from monolayers of scattered single cells to thick, mucous structures of macroscopic dimensions (microbial mats; algal‐microbial associations; trickling filter biofilms). During recent years the structure of biofilms from many different environments has been documented and evaluated by use of a broad variety of microscopic, physico‐chemical and molecular biological techniques, revealing a generally complex 3D structure. Parallel to these investigations more and more complex mathematical models and simulations were developed to explain the development, structures, and interactions of biofilms. The forces determining the spatial structure of biofilms, including microcolonies, extracellular polymeric substances (EPS), and channels, are still the subject of controversy. To achieve conclusive explanations for the structures observed in biofilms the cooperation of both fields of investigation, modelling and experimental research, is necessary. The expanding field of molecular techniques not only allows more and more detailed documentation of the spatial distribution of species, but also of functional activities of single cells in their biofilm environment. These new methods will certainly reveal new insights in the mechanisms involved in the developmental processes involved in the formation and behavior of biofilms.
    Keywords: Biofilm ; Structure ; Species Diversity ; Functional Heterogeneity ; Development
    ISSN: 0168-6445
    E-ISSN: 1574-6976
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: FEMS Microbiology Ecology, 2000, Vol.32(3), pp.215-223
    Description: Abstract The response of sulfate reducing bacteria (SRB) to oxygen stress under oligotrophic conditions in particle-free systems was studied in (i) sterile Berlin drinking water; (ii) mineral medium; and (iii) in coculture experiments with aerobic bacteria. Using a polyphasic approach including anaerobic cultivation, fluorescent in situ hybridization (FISH) and digital image analysis, the behavior of the strains zt3l and zt10e, isolated from Berlin groundwater and affiliated to the family Desulfovibrionaceae, was compared to the type strains Desulfomicrobium baculatum and Desulfovibrio desulfuricans. Anaerobic deep agar dilution series were performed for the determination of cell culturability. FISH and subsequent digital image analysis of probe-conferred fluorescence intensities were used for the assessment of metabolic activity. For the in situ identification of both isolates in coculture tests, two strain-specific oligonucleotides were developed and evaluated. The total cell counts of stressed SRB in drinking water decreased during the course of the assay dependent on the strain. Both environmental isolates could be cultured for a longer period than cells of D. baculatum and D. desulfuricans, respectively. The FISH intensities showed a strain-specific behavior. When exposed to simultaneous oxygen stress and carbon limitation in mineral medium, total cell counts of all four strains remained constant throughout a period of 72 days. The rate of culturability differed between the investigated strains. The decrease of metabolic activity as assessed by FISH was a strain-specific property. Exposure of SRB to oxygen stress and carbon starvation in coculture experiments with Aquabacterium commune resulted in strain dependent prolonged culturability and a delayed decrease of the metabolic activity compared to pure culture tests for all strains tested. Total cell counts of SRB were constant throughout the whole experiment.
    Keywords: Sulfate Reducing Bacterium ; Drinking Water ; Oxygen Stress ; Fluorescent in Situ Hybridization ; Digital Image Analysis ; Environmental Sciences ; Biology
    ISSN: 0168-6496
    E-ISSN: 1574-6941
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Language: English
    In: FEMS Microbiology Ecology, 1997, Vol.22(4), pp.265-279
    Description: Fluorescence-labeled oligonucleotide probes were applied, combined with in situ reduction of the fluorochrome 5-cyano-2,3-ditolyl tetrazolium chloride (CTC), to describe the development of bacterial density, phylogenetic diversity and bacterial metabolic activity during the formation of drinking water biofilms. Polyethylene and glass surfaces exposed to drinking water in a modified Robbins device were rapidly colonized by a biofilm community of phylogenetically diverse prokaryotes, and cell density of the biofilm community was strictly controlled by grazing eukaryotic organisms. In situ hybridization with group-specific rRNA-targeted oligonucleotide probes revealed the following: (i) the prevalence of bacteria belonging to the beta-subclass of Proteobacteria within the bacterial biofilm populations; (ii) differences in the population composition, assessed by phylogenetic probes, depended on the surface properties of the substrata; (iii) the influence of water retention time on variations in population structure; and (iv) the presence of bacteria belonging to the family Legionellaceae associated with grazing protozoa. The metabolic potential of bacteria was assessed during biofilm formation using fluorescence signals after in situ hybridization and the reduction of the redox dye CTC as an indicator of respiratory activity. Respiratory activity and ribosome content of adherent bacterial cells decreased continuously during the early stages of the biofilm. After 35 days the percentage of CTC-reducing cells stabilized at 30%, and the amount of hybridized cells stabilized at 55%, of the initial cell number. To ascertain the amount of dormant, but potentially active cells, we established a new method, defined as probe active counts (PAC). Biofilms were incubated with a mixture of appropriate carbon sources and an antibiotic preventing bacterial cell division, followed by the determination of metabolic activity by in situ hybridization. By this approach the percentage of hybridized cells could be increased from 50% to 80% of total bacterial cell counts in the oligotrophic drinking water biofilms. ; Includes references ; p. 265-279.
    Keywords: Drinking Water Biofilm ; In Situ Hybridization ; Probe Active Count ; Ctc Reduction ; Environmental Sciences ; Biology
    ISSN: 0168-6496
    E-ISSN: 1574-6941
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Language: English
    In: FEMS Microbiology Ecology, 1998, Vol.25(1), pp.43-61
    Description: Abstract A comprehensive panel of ten 16S rRNA targeted oligonucleotides specific for mesophilic sulfate-reducing bacteria (SRB) within the δ-subclass of Proteobacteria was developed as a diagnostic tool and evaluated for its specificity and in situ applicability. Five probes (DSD131, DSBO224, DSV407, DSR651, DSS658) are specific on genus level and five probes identify distinct phylogenetic subbranches within the families Desulfobacteriaceae (DSMA488, DSB985) and Desulfovibrionaceae (DSV214, DSV698, DSV1292). All oligonucleotides were checked for their specificity by computer aided comparative sequence analysis. For in situ application optimal stringency conditions were adjusted for each fluorescence-labelled probe performing whole cell hybridizations using target and non-target organisms. Activated sludge flocs from different stages within the aeration tank of a large municipal wastewater treatment plant were examined by in situ hybridizations with the indocarbocyanine- (Cy3-) labelled SRB-specific probes. The relative abundance and the spatial organization of single SRB were monitored with epifluorescence and confocal laser scanning microscopy. Individual sulfate-reducing cells could be visualized and the number of cells ranged from 0.5 to 8% of the total cell counts within all stages of the activated sludge process and the final clarifier. Cells yielding strong fluorescence signals after hybridization with the newly developed probes were not restricted to anoxic and anaerobic compartments, but were also clearly detectable in the aeration zones of the treatment plant.
    Keywords: Sulfate-Reducing Bacteria ; Activated Sludge ; In Situ Hybridization ; Environmental Sciences ; Biology
    ISSN: 0168-6496
    E-ISSN: 1574-6941
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages