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Berlin Brandenburg

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  • 1
    Language: English
    In: Applied and environmental microbiology, February 2013, Vol.79(4), pp.1410-3
    Description: To study the role of broad-host-range IncP-1 plasmids in bacterial adaptability to irregular environmental challenges, a quantitative real-time PCR assay was developed that specifically detects the korB gene, which is conserved in all IncP-1 plasmids, in environmental samples. IncP-1 plasmid dynamics in a biopurification system for pesticide wastes were analyzed.
    Keywords: Environmental Microbiology ; Bacteroidetes -- Genetics ; Plasmids -- Analysis
    ISSN: 00992240
    E-ISSN: 1098-5336
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  • 2
    Language: English
    In: Water Research, 2010, Vol.44(6), pp.1785-1796
    Description: A novel aerated treatment pond for enhanced biodegradation of groundwater contaminants was tested under field conditions. Coconut fibre and polypropylene textiles were used to encourage the development of contaminant-degrading biofilms. Groundwater contaminants targeted for removal were benzene, methyl -butyl ether (MTBE) and ammonium. Here, we present data from the first 14 months of operation and compare contaminant removal rates, volatilization losses, and biofilm development in one pond equipped with coconut fibre to another pond with polypropylene textiles. Oxygen concentrations were constantly monitored and adjusted by automated aeration modules. A natural transition from anoxic to oxic zones was simulated to minimize the volatilization rate of volatile organic contaminants. Both ponds showed constant reductions in benzene concentrations from 20 mg/L at the inflow to about 1 μg/L at the outflow of the system. A dynamic air chamber (DAC) measurement revealed that only 1% of benzene loss was due to volatilization, and suggests that benzene loss was predominantly due to aerobic mineralization. MTBE concentration was reduced from around 4 mg/L at the inflow to 3.4–2.4 mg/L in the system effluent during the first 8 months of operation, and was further reduced to 1.2 mg/L during the subsequent 6 months of operation. Ammonium concentrations decreased only slightly from around 59 mg/L at the inflow to 56 mg/L in the outflow, indicating no significant nitrification during the first 14 months of continuous operation. Confocal laser scanning microscopy (CLSM) demonstrated that microorganisms rapidly colonized both the coconut fibre and polypropylene textiles. Microbial community structure analysis performed using denaturing gradient gel electrophoresis (DGGE) revealed little similarity between patterns from water and textile samples. Coconut textiles were shown to be more effective than polypropylene fibre textiles for promoting the recruitment and development of MTBE-degrading biofilms. Biofilms of both textiles contained high numbers of benzene metabolizing bacteria suggesting that these materials provide favourable growth conditions for benzene degrading microorganisms.
    Keywords: Groundwater Remediation ; Geotextiles ; Mtbe and Benzene Degradation ; Compartment Transfer ; Engineering
    ISSN: 0043-1354
    E-ISSN: 1879-2448
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  • 3
    In: FEMS Microbiology Letters, 2013, Vol. 348(2), pp.127-132
    Description: LowGC-type plasmids conferring resistance to sulfonamides have been frequently isolated from manure and manured soil. However, knowledge on the dynamics of plasmid-carrying populations in soil and their response to the presence of sulfonamides is scarce. Here, we investigated effects of the sulfonamide resistance conferring plasmid pHHV216 on the fitness of Acinetobacter baylyi BD413 in soil after application of manure with or without the sulfonamide antibiotic sulfadiazine (SDZ). The persistence of A. baylyi BD413 pHHV216 in competition to its plasmid-free variant was followed in soil microcosms. CFU counts showed a decrease in A. baylyi BD413 in manured soils over the experimental period of 32 days by about 0.5 log units. The proportion of the plasmid-carrying populations decreased from 50 to 〈 40% in the absence of SDZ, while the proportion of plasmid-carrying BD413 increased from 50 to about 65% with SDZ added. The data suggest that SDZ introduced via manure into soil was bioaccessible, providing a fitness advantage for the plasmid-carrying population of BD413 in soil, while the plasmid conferred a fitness disadvantage when selective pressure by SDZ was absent. In future, this method may be used as a tool for the assessment of bioavailability of antibiotics in soil.
    Keywords: Plasmid ; Sulfadiazine ; Antibiotic Resistance ; Soil ; Antibiotic Selection ; Host Fitness
    ISSN: 0378-1097
    E-ISSN: 1574-6968
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  • 4
    In: FEMS Microbiology Ecology, 2014, Vol. 87(1), pp.78-88
    Description: Difloxacin (DIF) belongs to the class of fluoroquinolone antibiotics that have been intensively used for the treatment of bacterial infections in veterinary and human medicine. The aim of this field study was to compare the effect of manure from DIF-treated pigs and untreated pigs on the bacterial community structure and resistance gene abundance in bulk soil and rhizosphere of maize. A significant effect of DIF manure on the bacterial community composition in bulk soil was revealed by denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA gene fragments amplified from total community DNA. In few samples, quinolone resistance genes qnrB and qnrS1/qnrS2 were detected by PCR and subsequent hybridization, while qnrA was not detected. Quantitative PCR revealed an increased abundance of the integrase gene intI1 of class I integrons and sulfonamide resistance genes sul1 and sul2 in DIF manure-treated bulk soil and rhizosphere, relative to 16S rRNA genes, while traN genes specific for LowGC-type plasmids were increased only in bulk soil. Principal component analysis of DGGE profiles suggested a manure effect in soil until day 28, but samples of days 71 and 140 were found close to untreated soil, indicating resilience of soil community compositions from disturbances by manure. 〈p〉〈fig id="fig0" position="float"〉 〈graphic alt-version="no" position="float" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="fem12191-toc-0001" xlink:type="simple"/〉〈/fig〉 〈/p〉
    Keywords: Difloxacin ; Resistance ; Dgge ; Soil ; Manure ; Rhizosphere
    ISSN: 01686496
    E-ISSN: 1574-6941
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  • 5
    In: PLoS ONE, 2014, Vol.9(3)
    Description: Large amounts of manure have been applied to arable soils as fertilizer worldwide. Manure is often contaminated with veterinary antibiotics which enter the soil together with antibiotic resistant bacteria. However, little information is available regarding the main responders of bacterial communities in soil affected by repeated inputs of antibiotics via manure. In this study, a microcosm experiment was performed with two concentrations of the antibiotic sulfadiazine (SDZ) which were applied together with manure at three different time points over a period of 133 days. Samples were taken 3 and 60 days after each manure application. The effects of SDZ on soil bacterial communities were explored by barcoded pyrosequencing of 16S rRNA gene fragments amplified from total community DNA. Samples with high concentration of SDZ were analyzed on day 193 only. Repeated inputs of SDZ, especially at a high concentration, caused pronounced changes in bacterial community compositions. By comparison with the initial soil, we could observe an increase of the disturbance and a decrease of the stability of soil bacterial communities as a result of SDZ manure application compared to the manure treatment without SDZ. The number of taxa significantly affected by the presence of SDZ increased with the times of manure application and was highest during the treatment with high SDZ-concentration. Numerous taxa, known to harbor also human pathogens, such as Devosia , Shinella , Stenotrophomonas , Clostridium , Peptostreptococcus , Leifsonia , Gemmatimonas , were enriched in the soil when SDZ was present while the abundance of bacteria which typically contribute to high soil quality belonging to the genera Pseudomonas and Lysobacter , Hydrogenophaga , and Adhaeribacter decreased in response to the repeated application of manure and SDZ.
    Keywords: Research Article ; Biology And Life Sciences ; Ecology And Environmental Sciences
    E-ISSN: 1932-6203
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  • 6
    Language: English
    In: Trends in Microbiology, September 2014, Vol.22(9), pp.536-545
    Description: Large amounts of veterinary antibiotics are applied worldwide to farm animals and reach agricultural fields by manure fertilization, where they might lead to an increased abundance and transferability of antibiotic-resistance determinants. In this review we discuss recent advances, limitations, and research needs in determining the fate of veterinary antibiotics and resistant bacteria applied with manure to soil, and their effects on the structure and function of soil microbial communities in bulk soils and the rhizosphere. The increased abundance and mobilization of antibiotic-resistance genes (ARGs) might contribute to the emergence of multi-resistant human pathogens that increasingly threaten the successful antibiotic treatment of bacterial infections.
    Keywords: Antibiotic-Resistance Genes ; Horizontal Gene Transfer ; Rhizosphere ; Biology
    ISSN: 0966-842X
    E-ISSN: 1878-4380
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  • 7
    Language: English
    In: Applied and Environmental Microbiology, 2011, Vol. 77(3), p.1086
    ISSN: 0099-2240
    ISSN: 00992240
    Source: American Society of Microbiology
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  • 8
    Language: English
    In: Applied and environmental microbiology, February 2011, Vol.77(3), pp.1086-96
    Description: Multidimensional compound-specific stable isotope analysis (CSIA) was applied in combination with RNA-based molecular tools to characterize methyl tertiary (tert-) butyl ether (MTBE) degradation mechanisms occurring in biofilms in an aerated treatment pond used for remediation of MTBE-contaminated groundwater. The main pathway for MTBE oxidation was elucidated by linking the low-level stable isotope fractionation (mean carbon isotopic enrichment factor [ε(C)] of -0.37‰ ± 0.05‰ and no significant hydrogen isotopic enrichment factor [ε(H)]) observed in microcosm experiments to expression of the ethB gene encoding a cytochrome P450 monooxygenase able to catalyze the oxidation of MTBE in biofilm samples both from the microcosms and directly from the ponds. 16S rRNA-specific primers revealed the presence of a sequence 100% identical to that of Methylibium petroleiphilum PM1, a well-characterized MTBE degrader. However, neither expression of the mdpA genes encoding the alkane hydroxylase-like enzyme responsible for MTBE oxidation in this strain nor the related MTBE isotope fractionation pattern produced by PM1 could be detected, suggesting that this enzyme was not active in this system. Additionally, observed low inverse fractionation of carbon (ε(C) of +0.11‰ ± 0.03‰) and low fractionation of hydrogen (ε(H) of -5‰ ± 1‰) in laboratory experiments simulating MTBE stripping from an open surface water body suggest that the application of CSIA in field investigations to detect biodegradation may lead to false-negative results when volatilization effects coincide with the activity of low-fractionating enzymes. As shown in this study, complementary examination of expression of specific catabolic genes can be used as additional direct evidence for microbial degradation activity and may overcome this problem.
    Keywords: Biodegradation, Environmental ; Chemical Fractionation -- Methods ; Cytochrome P-450 Enzyme System -- Metabolism ; Methyl Ethers -- Metabolism ; Water Pollutants, Chemical -- Metabolism ; Water Purification -- Methods
    ISSN: 00992240
    E-ISSN: 1098-5336
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  • 9
    In: FEMS Microbiology Ecology, July 2013, Vol.85(1), pp.14-26
    Description: We identified phylotypes performing distinct functions related to benzene degradation in complex microbial biofilms from an aerated treatment pond containing coconut textile. ‐ and protein‐stable isotope probing () and compound‐specific stable isotope analysis were applied to delineate bacteria and predominant pathways involved in the degradation of benzene. In laboratory microcosms, benzene was degraded at rates of ≥ 11 μM per day and per gram coconut textile under oxic conditions. Carbon isotope fractionation with isotopic enrichment factors (ε) of −0.6 to −1‰ and no significant hydrogen isotope fractionation indicated a dihydroxylation reaction for the initial ring attack. The incubation with []‐benzene led to formation accompanied by ‐labeling of and proteins of the active biomass. Phylogenetic analysis of the ‐labeled revealed that phylotypes related to ,, and within the predominantly assimilated carbon from benzene. Although the phylogenetic classification of identified ‐labeled proteins was biased by the incomplete metagenome information of public databases, it matched with ‐ results at genus level. The detection of ‐labeled proteins related to toluene dioxygenase and catechol 2,3‐dioxygenase suggests benzene degradation by a dihydroxylation pathway with subsequent ‐cleavage of formed catechol.
    Keywords: Benzene Degradation ; Compound‐Specific Stable Isotope Analysis ; Protein‐/‐ ; Stable Isotope Probing
    ISSN: 0168-6496
    E-ISSN: 1574-6941
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  • 10
    Language: English
    In: Applied and environmental microbiology, March 2013, Vol.79(5), pp.1704-11
    Description: Spreading manure containing antibiotics in agriculture is assumed to stimulate the dissemination of antibiotic resistance in soil bacterial populations. Plant roots influencing the soil environment and its microflora by exudation of growth substrates might considerably increase this effect. In this study, the effects of manure from pigs treated with sulfadiazine (SDZ), here called SDZ manure, on the abundance and transferability of sulfonamide resistance genes sul1 and sul2 in the rhizosphere of maize and grass were compared to the effects in bulk soil in a field experiment. In plots that repeatedly received SDZ manure, a significantly higher abundance of both sul genes was detected compared to that in plots where manure from untreated pigs was applied. Significantly lower abundances of sul genes relative to bacterial ribosomal genes were encountered in the rhizosphere than in bulk soil. However, in contrast to results for bulk soil, the sul gene abundance in the SDZ manure-treated rhizosphere constantly deviated from control treatments over a period of 6 weeks after manuring, suggesting ongoing antibiotic selection over this period. Transferability of sulfonamide resistance was analyzed by capturing resistance plasmids from soil communities into Escherichia coli. Increased rates of plasmid capture were observed in samples from SDZ manure-treated bulk soil and the rhizosphere of maize and grass. More than 97% of the captured plasmids belonged to the LowGC type (having low G+C content), giving further evidence for their important contribution to the environmental spread of antibiotic resistance. In conclusion, differences between bulk soil and rhizosphere need to be considered when assessing the risks associated with the spreading of antibiotic resistance.
    Keywords: Drug Resistance, Bacterial ; Gene Transfer, Horizontal ; Manure ; Soil Microbiology ; Anti-Bacterial Agents -- Therapeutic Use ; Sulfadiazine -- Therapeutic Use
    ISSN: 00992240
    E-ISSN: 1098-5336
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