| 1. |
- Carlsson, Susanne, et al.
(författare)
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Affinity of galectin-8 and its carbohydrate recognition domains for ligands in solution and at the cell surface.
- 2007
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 0959-6658 .- 1460-2423. ; 17:6, s. 663-76
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Tidskriftsartikel (refereegranskat)abstract
- Galectin-8 has two different carbohydrate recognition domains (CRDs), the N-terminal Gal-8N and the C-terminal Gal-8C linked by a peptide, and has various effects on cell adhesion and signaling. To understand the mechanism for these effects further, we compared the binding activities of galectin-8 in solution with its binding and activation of cells. We used glycan array analysis to broaden the specificity profile of the two galectin-8 CRDs, as well as intact galectin-8s (short and long linker), confirming the unique preference for sulfated and sialylated glycans of Gal-8N. Using a fluorescence anisotropy assay, we examined the solution affinities for a subset of these glycans, the highest being 50 nM for NeuAcalpha2,3Lac by Gal-8N. Thus, carbohydrate-protein interactions can be of high affinity without requiring multivalency. More importantly, using fluorescence polarization, we also gained information on how the affinity is built by multiple weak interactions between different fragments of the glycan and its carrier molecule and the galectin CRD subsites (A-E). In intact galectin-8 proteins, the two domains act independently of each other in solution, whereas at a surface they act together. Ligands with moderate or weak affinity for the isolated CRDs on the array are bound strongly by intact galectin-8s. Also galectin-8 binding and signaling at cell surfaces can be explained by combined binding of the two CRDs to low or medium affinity ligands, and their highest affinity ligands, such as sialylated galactosides, are not required.
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| 2. |
- Andersson, Anna, et al.
(författare)
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Evaluating gas chromatography with a halogen-specific detector for the determination of disinfection by-products in drinking water
- 2019
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Ingår i: Environmental Science and Pollution Research. - : Springer Berlin/Heidelberg. - 0944-1344 .- 1614-7499. ; 26, s. 7305-7314
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Tidskriftsartikel (refereegranskat)abstract
- The occurrence of disinfection by-products (DBPs) in drinking water has become an issue of concern during the past decades. The DBPs pose health risks and are suspected to cause various cancer forms, be genotoxic and have negative developmental effects. The vast chemical diversity of DBPs makes comprehensive monitoring challenging. Only few of the DBPs are regulated and included in analytical protocols. In this study, a method for simultaneous measurement of 20 DBPs from five different structural classes (both regulated and non-regulated) was investigated and further developed for 11 DBPs using solid phase extraction and gas chromatography coupled with a halogen specific detector (XSD). The XSD was highly selective towards halogenated DBPs, providing chromatograms with little noise. The method allowed detection down to 0.05 µg/L and showed promising results for the simultaneous determination of a range of neutral DBP classes. Compounds from two classes of emerging DBPs, more cytotoxic than the “traditional” regulated DBPs, were successfully determined using this method. However, haloacetic acids (HAAs) should be analyzed separately as some HAA methyl esters may degrade giving false positives of trihalomethanes (THMs). The method was tested on real water samples from two municipal waterworks where the target DBP concentrations were found below the regulatory limits of Sweden.
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| 3. |
- Andersson, Anna, et al.
(författare)
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Waterworks-specific composition of drinking water disinfection by-products
- 2019
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Ingår i: Environmental Science. - Cambridge : Royal Society of Chemistry. - 2053-1400 .- 2053-1419. ; :5, s. 861-872
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Tidskriftsartikel (refereegranskat)abstract
- Reactions between chemical disinfectants and natural organic matter (NOM) upon drinking water treatment result in formation of potentially harmful disinfection by-products (DBPs). The diversity of DBPs formed is high and a large portion remains unknown. Previous studies have shown that non-volatile DBPs are important, as much of the total toxicity from DBPs has been related to this fraction. To further understand the composition and variation of DBPs associated with this fraction, non-target analysis with ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was employed to detect DBPs at four Swedish waterworks using different types of raw water and treatments. Samples were collected five times covering a full year. A common group of DBPs formed at all four waterworks was detected, suggesting a similar pool of DBP precursors in all raw waters that might be related to phenolic moieties. However, the largest proportion (64–92%) of the assigned chlorinated and brominated molecular formulae were unique, i.e. were solely found in one of the four waterworks. In contrast, the compositional variations of NOM in the raw waters and samples collected prior to chemical disinfection were rather limited.This indicated that waterworks-specific DBPs presumably originated from matrix effects at the point of disinfection, primarily explained by differences in bromide levels, disinfectants (chlorine versus chloramine) and different relative abundances of isomers among the NOM compositions studied. The large variation of observed DBPs in the toxicologically relevant non-volatile fraction indicates that non-targeted monitoring strategies might be valuable to ensure relevant DBP monitoring in the future.
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| 4. |
- Bastviken, David, et al.
(författare)
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Chloride retention in forest soil by microbial uptake and by natural chlorination of organic matter
- 2007
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Ingår i: Geochimica Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 71:13, s. 3182-3192
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Tidskriftsartikel (refereegranskat)abstract
- Inorganic chlorine (i.e. chloride; Cl-in) is generally considered inert in soil and is often used as a tracer of soil and ground water movements. However, recent studies indicate that substantial retention or release of Cl-in can occur in soil, but the rates and processes responsible under different environmental conditions are largely unknown. We performed Cl-36 tracer experiments which indicated that short-term microbial uptake and release of Cl-in, in combination with more long-term natural formation of chlorinated organic matter (Cl-org), caused Cl-in imbalances in coniferous forest soil. Extensive microbial uptake and release of Cl-in occurred over short time scales, and were probably associated with changes in environmental conditions. Up to 24% of the initially available Clin within pore water was retained by microbial uptake within a week in our experiments, but most of this Cl-in, was released to the pore water again within a month, probably associated with decreasing microbial populations. The natural formation of Clorg resulted in a net immobilization of 4% of the initial pore water Clin over four months. If this rate is representative for the area where soil was collected, Clorg formation would correspond to a conversion of 25% of the yearly wet deposition of Cl-in. The study illustrates the potential of two Clin retaining processes in addition to those previously addressed elsewhere (e.g. uptake of chloride by vegetation). Hence, several processes operating at different time scales and with different regulation mechanisms can cause Clin imbalances in soil. Altogether, the results of the present study (1) provide evidence that Cl-in cannot be assumed to be inert in soil, (2) show that microbial exchange can regulate pore water Cl-in, concentrations and (3) confirm the controversial idea of substantial natural chlorination of soil organic matter.
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| 5. |
- Karlsson, Susanne, 1967-, et al.
(författare)
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Drinking water off-flavour caused by the formation of short-chain fatty acids in slow sand filters
- 1995
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Ingår i: Water Science and Technology. - 0273-1223 .- 1996-9732. ; 31:11, s. 49-54
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Tidskriftsartikel (refereegranskat)abstract
- A case study carried out at a municipal drinking water treatment plant in southern Sweden showed that the formation of short-chain fatty acids in slow sand filters can result in severe off-flavour problems. When an extract of the headspace of the surface layer of a sand filter was subjected to gas chromatographic analysis with sensory detection (GC sniffing), several strong, rancid odours were detected. Mass spectrometric analysis of the same extract, before and after methylation, showed that substantial amounts of butyric acid, valeric acid and isovaleric acid were present in the analysed sample. The off-flavour caused by these compounds was removed by repeated shock chlorination of the malfunctioning slow sand filter. Analysis of fatty acid esters may provide an early warning of the described off-flavour problem.
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| 6. |
- Karlsson, Susanne, 1967-
(författare)
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Phenols, anisoles and fatty acids causing odour problems in drinking water
- 2003
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Taste and odour problems are the major causes of consumer complaints regarding drinking water in the industrialised world. Nevertheless, as yet there are no mandatory requirements to identify the compounds that are responsible for the observed off-flavour. This thesis shows that gas chromatographic analysis with mass spectrometric and sensory detection provides an efficient tool for such investigations. The enrichment that precedes the gas chromatographic analysis can normally be based on stripping volatile or semi-volatile organic compounds. Due to the low blank level obtained with the open stripping system used in the present study, well-known odorous compounds, such as geosmin, 2- methylisoborneol (MIB) and 2,4,6-trichloroanisole (2,4,6-TCA), could be detected at levels below their threshold odour concentrations. However, this thesis also shows that compounds that are too hydrophilic to be enriched by stripping can play an important role, either as precursors of odorous compounds or as the direct cause of off-flavours. In particular, we found that natural formation of 2,4,6-trichlorophenol (2,4,6-TCP) may lead to the formation of 2,4,6-TCA in the distribution system. Furthermore, a study of a municipal treatment plant showed that short-chain carboxylic acids can be formed in slow sand filters, giving the finished water a rancid or nauseating flavour. Collectively, the results of the present study clearly show the importance of regarding the entire process from raw water supply to the consumer's tap as an integrated system. Off-flavours may originate from processes in the raw water supply, during treatment and in the distribution system.
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| 7. |
- Karlsson, Susanne, 1967-, et al.
(författare)
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UV-light induced mineralization of organic matter bound chlorine in Lake BjΣn, Sweden - A laboratory study
- 2003
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Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 52:2, s. 463-469
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Tidskriftsartikel (refereegranskat)abstract
- Surface water and aqueous solutions of isolated organic matter from a humic rich lake in southern Sweden were exposed to artificial UV radiation to investigate the UV light induced influence on organic matter bound chlorine in natural systems. It was found that the photodegradation of organic matter bound chlorine was more pronounced than the photodegradation of organic carbon. After 120 h of irradiation of the isolated organic matter, only 35% of the initial organochlorine was still in the solution compared to about 70% of the dissolved organic carbon (DOC). A similar result was obtained for unfractionated surface water. Furthermore, our results indicate that the loss of organic chlorine was mainly due to a mineralization of organic chlorine into chloride ions. The total decrease of organic chlorine after 120 h was 32 ╡g Clorg l-1, of which the major part disappeared in the initial irradiation phase. A similar increase was observed in the chloride concentration (34 ╡g Cl- l-1).
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| 8. |
- Lindberg, Elisabeth, et al.
(författare)
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Reflective seminaries grounded in caring science and lifeworld theory : A phenomenological study from the perspective of nursing students
- 2018
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Ingår i: Nurse Education Today. - Amsterdam : Elsevier. - 0260-6917 .- 1532-2793. ; 61, s. 60-65
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Tidskriftsartikel (refereegranskat)abstract
- Background Creative strategies are needed in nurse education to integrate theory, practice and lived experiences. Towards that end, reflective seminars, conducted in congruence with reflective lifeworld theory and caring science, were implemented during a three-year nursing programme. The reflection seminars took place during the theoretical parts of education and the clinical placements. Each reflection group consisted of six to nine students, and the seminars were led by a lecturer from the university.Objectives This article aims to describe the experiences of learning about caring science by participating in reflective seminars that were integrated into courses during a three-year nursing education programme.Design A phenomenological approach was used, and qualitative group interviews were conducted.Setting The study was conducted at a university in southern Sweden.Participants Twenty three students, 19 women and four men, volunteered to participate. All participants were at the end of a three-year nurse education programme. Data were collected through four group interviews with five to seven participants in each group.Methods This study used a reflective lifeworld research approach based on phenomenological philosophy.Results The findings reveal that nursing students experience reflective seminars as being valuable for their professional development. The result is described in more detail via four meaning units: An obtained awareness of the value of reflection in clinical practice; Reflection contributes to an approach of thoughtfulness; Caring science has become second nature, and Reflection as a strength and a challenge at the threshold of a profession.Conclusions This study contributes to the understanding of reflective seminars grounded in lifeworld theory as a didactic strategy that enables students to increase their knowledge of caring science and develop their reflective skills.
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| 9. |
- Shao, Linus Ruijin, 1964, et al.
(författare)
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Down-Regulation of Cilia-Localized IL-6R{alpha} by 17{beta}-Estradiol in Mouse and Human Fallopian Tubes.
- 2009
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Ingår i: American journal of physiology. Cell physiology. - : American Physiological Society. - 0363-6143 .- 1522-1563. ; 297:1
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Tidskriftsartikel (refereegranskat)abstract
- The action of Interleukin-6 (IL-6) impacts female reproduction. Although IL-6 was recently shown to inhibit cilia activity in human fallopian tubes in vitro, the molecular mechanisms underlying IL-6 signaling to tubal function remain elusive. Here, we investigate the cellular localization, regulation, and possible function of two IL-6 receptors (IL-6Ralpha and gp130) in mouse and human fallopian tubes in vivo. We show that IL-6Ralpha is restricted to the cilia of epithelial cells in both mouse and human fallopian tubes. Exogenous 17beta-estradiol (E2), but not progesterone (P4), causes a time-dependent decrease in IL-6Ralpha expression which is blocked by the estrogen receptor (ER) antagonist ICI 182,780. Exposure of different ER-selective agonists, PTT or DPN, demonstrated an ER subtype-specific regulation of IL-6Ralphaalpha in mouse fallopian tubes. In contrast to IL-6Ralpha, gp130 was detected in tubal epithelial cells in mice but not in humans. In humans, gp130 was found in the muscle cells and was decreased in the periovulatory and luteal phases during the reproductive cycles, indicating a species-specific expression and regulation of gp130 in the fallopian tube. Expression of tubal IL-6Ralpha and gp130 in IL-6 knockout mice was found to be normal; however, E2 treatment increased IL-6Ralpha, but not gp130, in IL-6 knockout mice compared to wild-type mice. Furthermore, expression levels of IL-6Ralpha, but not gp130, decreased in parallel with estrogenic accelerated oocyte-cumulus complex (OCC) transport in mouse fallopian tubes. Our findings unveil a potential role for cilia-specific IL-6Ralpha in the regulation of OCC transport and suggest an estrogen-regulatory pathway of IL-6Ralpha in the fallopian tube. Key words: estrogen, IL-6R, cilia, fallopian tube.
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| 10. |
- Villarejo, Arsenio, et al.
(författare)
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Evidence for a protein transported through the secretory pathway en route to the higher plant chloroplast
- 2005
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Ingår i: Nature Cell Biology. - : Springer Nature. - 1465-7392 .- 1476-4679. ; 7:12, s. 1224-1231
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Tidskriftsartikel (refereegranskat)abstract
- In contrast to animal and fungal cells, green plant cells contain one or multiple chloroplasts, the organelle(s) in which photosynthetic reactions take place. Chloroplasts are believed to have originated from an endosymbiotic event and contain DNA that codes for some of their proteins. Most chloroplast proteins are encoded by the nuclear genome and imported with the help of sorting signals that are intrinsic parts of the polypeptides. Here, we show that a chloroplast-located protein in higher plants takes an alternative route through the secretory pathway, and becomes N-glycosylated before entering the chloroplast.
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