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- Eriksson, Sara, 1974, et al.
(författare)
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Indicators of petroleum hydrocarbon biodegradation in anaerobic granitic groundwater
- 2006
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Ingår i: Geomicrobiology Journal. - : Informa UK Limited. - 0149-0451 .- 1521-0529. ; 23:1, s. 45-58
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to find indicators of petroleum biodegradation in granitic groundwater. Both pristine and contaminated groundwaters from boreholes around petroleum storage vaults located approximately 40 m below the surface in granite and with storage capacities of up to 120,000 m(3) were sampled. Total numbers of microorganisms, "most probable numbers" (MPN) of anaerobic bacteria, and chemical indications of microbial activity were determined in the groundwater. Hydrocarbon contaminants and metabolites were detected using gas chromatographymass spectrometry (GC-MS). In contaminated groundwater, the total number of microorganisms was 2-4 x 10(6) ml(-1), which was significantly higher than the 6 x 10(4) ml(-1) found in pristine groundwater. This microbial abundance was also reflected in the MPN analysis. Up to 7 x 10(4) nitrate-, 2 x 10(3) iron-, and 3 x 10(4) sulfate-reducing bacteria were detected in contaminated groundwaters. In such groundwaters, depletion of anaerobic electron acceptors and detection of reduced species could be established. We also proposed using a high alkalinity/hardness of water quota (A/H quota) as an indicator of microbial activity. In contaminated groundwaters the A/H quota averaged 2.8, while in pristine groundwater the same was only 1.3. Moreover, the presence of 20 oxidized petroleum hydrocarbons, i.e., putative metabolites of which 9 were strictly intracellular, was detected in the contaminated groundwaters. Phylogenetic neighbor-joining analysis of 16S rRNA genes provided information about the bacterial communities. The bacteria in contaminated groundwater were found to be strikingly similar to bacteria in other hydrocarbon-contaminated environments.
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| 2. |
- Eriksson, Sara, 1974, et al.
(författare)
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Propylphenols are metabolites in the anaerobic biodegradation of propylbenzene under iron-reducing conditions
- 2005
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Ingår i: Biodegradation. - : Springer Science and Business Media LLC. - 1572-9729 .- 0923-9820. ; 16:3, s. 253-263
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Tidskriftsartikel (refereegranskat)abstract
- The metabolism of monoaromatic hydrocarbons by an iron-reducing bacterial enrichment culture originating from diesel-contaminated groundwater was examined using d 7 -propylbenzene as a model hydrocarbon. Sequence analysis of the 16S rDNA gene showed that the dominant part (10 of 10 clones) of the enrichment culture consisted of a bacterium closely related to clones found in benzene-contaminated groundwater and to the iron-reducing β- proteobacterium, Rhodoferax ferrireducens (similarity values were 99.5% and 98.3%, respectively). In degradation studies conducted over 18 weeks, d 7 -propylphenols were detected by gas chromatography-mass spectrometry (GC/MS) as intra-cellular metabolites concomitant with cell growth in the cultures. The amount of propylphenols increased during the exponential growth phase, and by the end of this phase 4 × 10 -14 moles of ferric iron were reduced and 3 × 10 -15 moles propylphenol produced for every cell formed. During the stationary growth phase the cell density was approximately 10 7 ml -1 , with significantly correlated amounts of propylphenols. Succinate derivates of propylbenzene or phenylpropanol previously shown to be the initial metabolites in the anaerobic degradation of alkylbenzenes could not be identified. This study is the first to report that oxidation of propylbenzene to propylphenols can initiate anaerobic propylbenzene degradation and that iron-reducing bacteria are responsible for this process. In addition, the study shows the importance of taking account of the metabolites adhering to solid phases when determining the extent of biodegradation, so as not to underestimate the extent of the process.
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| 5. |
- Ellegård, Sander, et al.
(författare)
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ERBB2 and PTPN2 gene copy numbers as prognostic factors in HER2-positive metastatic breast cancer treated with trastuzumab
- 2019
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Ingår i: Oncology Letters. - Athens, Greece : Spandidos Publications. - 1792-1074 .- 1792-1082. ; 17:3, s. 3371-3381
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Tidskriftsartikel (refereegranskat)abstract
- Trastuzumab has markedly improved the treatment and long-term prognosis of patients with HER2-positive breast cancer. A frequent clinical challenge in patients with relapsing and/or metastatic disease is de novo or acquired trastuzumab resistance, and to date no predictive biomarkers for palliative trastuzumab have been established. In the present study, the prognostic values of factors involved in the HER2-associated PI3K/Akt signalling pathway were explored. The first 46 consecutive patients treated at the Department of Oncology, Linkoping University Hospital between 2000 and 2007 with trastuzumab for HER2-positive metastatic breast cancer were retrospectively included. The gene copy number variation and protein expression of several components of the PI3K/Akt pathway were assessed in the tumour tissue and biopsy samples using droplet digital polymerase chain reaction and immunohistochemistry. Patients with tumours displaying a high-grade ERBB2 (HER2) amplification level of amp;gt;= 6 copies had a significantly improved overall survival hazard ratio [(HR)=0.4; 95%, confidence interval (CI): 0.2-0.9] and progression-free survival (HR=0.3; 95% CI: 0.1-0.7) compared with patients with tumours harbouring fewer ERBB2 copies. High-grade ERBB2 amplification was significantly associated with the development of central nervous system metastases during palliative treatment. Copy gain (amp;gt;= 3 copies) of the gene encoding the tyrosine phosphatase PTPN2 was associated with a shorter overall survival (HR=2.0; 95% CI: 1.0-4.0) and shorter progression-free survival (HR=2.1; 95% CI: 1.0-4.1). In conclusion, high ERBB2 amplification level is a potential positive prognostic factor in trastuzumab-treated HER2-positive metastatic breast cancer, whereas PTPN2 gain is a potential negative prognostic factor. Further studies are warranted on the role of PTPN2 in HER2 signalling.
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| 6. |
- Ferris, F. G., et al.
(författare)
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Geochemistry of acidic Rio Tinto headwaters and role of bacteria in solid phase metal partitioning
- 2004
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Ingår i: Chemical Geology. - : Elsevier BV. - 0009-2541. ; 212:3-4, s. 291-300
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Tidskriftsartikel (refereegranskat)abstract
- Mining operations in the Rio Tinto area, southwest Spain, have created a historical pollution problem in the river and estuary. The fate of metals along the Rio Tinto river and estuary has been previously characterized, but little is known about transport and behaviour of metals and other elements in the headwaters of the river. The headwaters are situated approximately 100 km (north east) from Huelva at the Mediterranean Sea, with three investigated sites in this area distributed over 100 m. Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) of aqueous and solid samples revealed Ca, Fe, Mg, Na, S, Si, and Al concentrations above 0.5 mM in the stream surface waters at all sites. Trace elements included K, Cu, Li, Mn, and Zn. Concentrations of particulate elements generally accounted for less than 10% of the total load. In deeper pools along the stream, brine water was found with notably higher levels of Fe, Mg, S, Si, and Al compared to the stream water. The brine had a pH of 1.9, while the surface stream waters had pH values of about 2.7. Groundwater from the seep on the bank of the stream was found to be chemically distinct from both surface stream water and the brine. Fe, S and Al were in the solid samples at 100 mmol/kg or more. K, Na, P, Si, As, Ba, Cu, Li, and Mn were characterized by intermediate concentrations, 1.0100 mmol/kg. A progressive downstream increase in particulate elemental concentrations was observed for P, Ba, Mn, Pb, Sr, V and Zn. Scanning electron microscopy (SEM) showed a variety of bacterial-like forms among the suspended particulates. In some instances, the bacteria appeared to be closely associated with or mineralized by inorganic precipitates. Transmission electron microscopy (TEM) revealed extensively mineralized bacterial cells in the solid sediment samples. The chemical composition of the investigated stream is attributed to inputs from groundwater and brines that likely evolve in response to evaporation during prolonged periods of moisture deficit in the summer. Planktonic bacteria were prominent components of the suspended particulate fraction in the stream; however, pH sorption edges for dissolved metals on bacteria are generally above pH 4.0, and therefore, it is unlikely that bacterial cells are an important component for transport of dissolved metals in the stream. Bottom sediments contain abundant highly mineralized bacteria with coatings of poorly crystalline iron oxyhydroxides and hydroxysulfate precipitates. Such bacterialmineral composites likely contribute to increased solid phase partitioning of dissolved metals in the Tinto river system.
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| 9. |
- Hallbeck, Lotta, 1957, et al.
(författare)
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Culture-dependent comparison of microbial diversity in deep granitic groundwater from two sites considered for a Swedish final repository of spent nuclear fuel
- 2012
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Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 1574-6941 .- 0168-6496. ; 81:1, s. 66-77
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Tidskriftsartikel (refereegranskat)abstract
- Site selection for a spent nuclear fuel (SNF) repository required analysis of microbial abundance and diversity at two Swedish sites, Forsmark and Laxemar-Simpevarp. Information about sulphate-reducing bacteria (SRB) was required, as sulphide could corrode copper SNF canisters. Total number of cells (TNC) and ATP were analysed, and plate counts and most probable number (MPN) analyses were conducted using eight media based on different electron donors and acceptors for specific microorganism physiological groups. Groundwater chemical composition and Eh were analysed; sampling depths were 112-978 m below sea level. TNC was 5.5 × 103 to 4.7 × 105 cells mL-1, correlating with ATP concentrations. Culturability in TNC percentage was 0.01-35.9, averaging 5.12. Culturable numbers varied greatly between sample positions and uncorrelated with depth. SRB were found in 29 samples and were below detection in three; the MPN of SRB correlated negatively with Eh, as did the MPN of acetogens. Data indicated that microbial sulphate reduction was ongoing in many sampled aquifers; published stable isotope data and modelling results supported this observation. The sites did not differ significantly, but the large data range suggested that analysis of more samples would enable detailed evaluation of microbial processes and their relationship with geochemical information. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
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