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  • 51.
    Axelsson Olsson, Diana
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olofsson, Jenny
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Svensson, Lovisa
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Griekspoor, Petra
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Waldenström, Jonas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Ellström, Patrik
    Clinical Bacteriology, Department of Medical Sciences, Uppsala University and Uppsala University Hospital, SE-751 85 Uppsala, Sweden.
    Olsen, Björn
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Amoebae and algae can prolong the survival of Campylobacter species in co-culture2010In: Experimental parasitology, ISSN 0014-4894, E-ISSN 1090-2449, Vol. 126, p. 59-64Article in journal (Refereed)
    Abstract [en]

    Several species of free-living amoebae can cause disease in humans. However, in addition to the direct pathogenicity of e.g. Acanthamoebae and Naegleria species, they are recognized as environmental hosts, indirectly involved in the epidemiology of many pathogenic bacteria. Although several studies have demonstrated intracellular survival of many different bacteria in these species, the extent of such interactions as well as the implications for the epidemiology of the bacterial species involved, are largely unknown and probably underestimated. In this study, we evaluated eight different unicellular eukaryotic organisms, for their potential to serve as environmental hosts for Campylobacter species. These organisms include four amoebozoas (Acanthamoeba polyphaga, Acanthamoeba castellanii, Acanthamoeba rhysodes and Hartmanella vermiformis), one alveolate (Tetrahymena pyriformis), one stramenopile (Dinobryon sertularia), one eugoenozoa (Euglena gracilis) and one heterolobosea (Naegleria americana). Campylobacter spp. including Campylobacter jejuni, Campylobacter coli and Campylobacter lari are the most common cause of gastroenteritis in the western world. Survival and replication of these three species as well as Campylobacter hyointestinalis were assessed in co-cultures with the eukaryotic organisms. Campylobacter spp. generally survived longer in co-cultures, compared to when incubated in the corresponding growth media. The eukaryotic species that best promoted bacterial survival was the golden algae D. sertularia. Three species of amoebozoas, of the genus Acanthamoeba promoted both prolonged survival and replication of Campylobacter spp. The high abundance in lakes, ponds and water distribution networks of these organisms indicate that they might have a role in the epidemiology of campylobacteriosis, possibly contributing to survival and dissemination of these intestinal pathogens to humans and other animals. The results suggest that not only C. jejuni, but a variety of Campylobacter spp. can interact with different eukaryotic unicellular organisms.

  • 52.
    Axelsson Olsson, Diana
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Svensson, Lovisa
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Olofsson, Jenny
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Salomon, Paulo
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Waldenström, Jonas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Ellström, Patrik
    Olsen, Björn
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Increase in Acid Tolerance of Campylobacter jejuni through Coincubation with Amoebae2010In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 76, no 13, p. 4194-4200Article in journal (Refereed)
    Abstract [en]

    Campylobacter jejuni is a recognized and common gastrointestinal pathogen in most parts of the world. Human infections are often food borne, and the bacterium is frequent among poultry and other food animals. However, much less is known about the epidemiology of C. jejuni in the environment and what mechanisms the bacterium depends on to tolerate low pH. The sensitive nature of C. jejuni stands in contrast to the fact that it is difficult to eradicate from poultry production, and even more contradictory is the fact that the bacterium is able to survive the acidic passage through the human stomach. Here we expand the knowledge on C. jejuni acid tolerance by looking at protozoa as a potential epidemiological pathway of infection. Our results showed that when C. jejuni cells were coincubated with Acanthamoeba polyphaga in acidified phosphate-buffered saline (PBS) or tap water, the bacteria could tolerate pHs far below those in their normal range, even surviving at pH 4 for 20 h and at pH 2 for 5 h. Interestingly, moderately acidic conditions (pH 4 and 5) were shown to trigger C. jejuni motility as well as to increase adhesion/internalization of bacteria into A. polyphaga. Taken together, the results suggest that protozoa may act as protective hosts against harsh conditions and might be a potential risk factor for C. jejuni infections. These findings may be important for our understanding of C. jejuni passage through the gastrointestinal tract and for hygiene practices used in poultry settings.

  • 53. Babiker, Adil A
    et al.
    Magnusson, Peetra U
    Ronquist, Gunnar
    Nilsson, Bo
    Nilsson Ekdahl, Kristina
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Mapping Pro- and Antiangiogenic Factors on the Surface of Prostasomes of Normal and Malignant Cell Origin2010In: The Prostate, ISSN 0270-4137, E-ISSN 1097-0045, Vol. 70, no 8, p. 834-847Article in journal (Refereed)
    Abstract [en]

    BACKGROUND. Angiogenesis is the formation of new blood vessels by capillary sprouting from pre-existing vessels. Tumor growth is angiogenesis-dependent and the formation of new blood vessels is associated with the increased expression of angiogenic factors. Prostasomes are secretory granules produced, stored and released by the glandular epithelial cells of the prostate. We investigated the expression of selected angiogenic and anti-angiogenic factors on the surface of prostasomes of different origins as well as the direct effect of prostasomes on angiogenesis.

    METHODS. VEGF, endothelin-1, endostatin, and thrombospondin-1 were determined on prostasomes from seminal fluid and human prostate cancer cell lines (DU145,PC-3,LNCaP) using different immunochemical techniques. Human dermal microvascular endothelial cells were incubated with seminal and DU145 cell-prostasomes and with radioactive thymidine. The effect of prostasomes on angiogenesis was judged by measuring the uptake of labeled thymidine. The presence of any deleterious effects of prostasomes on the endothelial cells was investigated using thymidine assay and confocal laser microscopy.

    RESULTS. VEGF and endothelin-1 were determined on malignant cell-prostasomes (no difference between cell lines) but not determined on seminal prostasomes. The same applies for the expression of endostatin but with much higher expression on malignant cell-prostasomes with obvious differences between them. Seminal and DU145 cell-prostasomes were found to have anti-angiogenic effect which was more expressed by DU145 cell-prostasomes. No deleterious effect of prostasomes on endothelial function was detected using either thymidine assay or microscopy.

    CONCLUSIONS. Prostasomes contain pro- and anti-angiogenic factors that function to counteract each other unless the impact from one side exceeds the other to bring about dysequilibrium.

  • 54. Babiker, Adil A
    et al.
    Ronquist, Gunnar
    Nilsson, Bo
    Nilsson Ekdahl, Kristina
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Prostasome Involvement in the Development and of Prostate Cancer2010In: Open Prostate Cancer Journal, ISSN 1876-8229, Vol. 3, p. 1-13Article, review/survey (Refereed)
    Abstract [en]

    Prostasomes are extracellularly occurring submicron, membrane-surrounded organelles produced by the epithelial cells of the prostate and present in semen after secretion. Even dedifferentiated prostate cancer cells have preserved their ability to produce and export prostasomes to the extracellular space. The precise physiological role of prostasomes is not known, although some of their properties assign them to important physiological and patho-physiological functions that could be exploited in prostate cancer growth and development. In this review, some new properties of seminal and malignant cell line (DU145, PC-3 and LNCaP) prostasomes will be discussed.There are typical differences in the expressions and activities of prostasomal CD59, ATPase, protein kinases and tissue factor (TF) as well as in the transfer of prostasomal CD59 to CD59-deficient erythrocytes (rabbit and human PNH erythrocytes). CD59, protein kinases and TF exhibit characteristic patterns of overexpression by malignant cell prostasomes. A high ATPase activity is recognized on seminal prostasomes with minimal activity on malignant cell prostasomes resulting in more residual ATP available for phosphorylation reactions. Several proteins are phosphorylated by prostasomal protein kinases, namely, complement component C3, fibrinogen, vitronectin and E-cadherin. Furthermore, TF is identified as the main endogenous phosphorylation substrate on prostasomes. In addition, prothrombotic effects of prostasomes are demonstrated. DU145 and PC-3 cell-derived prostasomes exert a higher clotting effect on whole blood and plasma compared to LNCaP cell-derived and seminal prostasomes.In conclusion, malignant cell prostasomes show an increased ability to interact with the biological system in favor of prostate cancer cell promotion and survival. The roles played by prostasomes in this context may improve the understanding of the mechanisms that help the prostate cancer cells to avoid the complement attack (CD59 transfer and phosphorylation and inactivation of C3), to promote angiogenesis (TF) and to metastasize. It may also provide a better understanding of some of the complications usually seen in some terminal prostate cancer patients like thrombotic events and tendency to develop disseminated intravascular coagulation.

  • 55.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Arístegui, Javier
    Gasol, Josep M
    Herndl, Gerhard J
    Microbial functioning and community structure variability in the mesopelagic and epipelagic waters of the subtropical Northeast Atlantic Ocean.2012In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 78, no 9, p. 3309-3316Article in journal (Refereed)
    Abstract [en]

    We analyzed the regional distribution of bulk heterotrophic prokaryotic activity (leucine incorporation) and selected single-cell parameters (cell viability and nucleic acid content) as parameters for microbial functioning, as well as bacterial and archaeal community structure in the epipelagic (0-200 m) and mesopelagic (200-1000 m) subtropical Northeast Atlantic Ocean. We selectively sampled three contrasting regions covering a wide range of surface productivity and oceanographic properties within the same basin: (i) the eddy field south of the Canary Islands, (ii) the open-ocean Subtropical Gyre and (iii) the upwelling filament off Cape Blanc. In the epipelagic waters, a high regional variation in hydrographic parameters and bacterial community structure was detected accompanied, however, by a low variability in microbial functioning. In contrast, mesopelagic microbial functioning was highly variable between the studied regions despite the homogeneous abiotic conditions found therein. More microbial functioning parameters indicated differences among the three regions within the mesopelagic (i.e., viability of cells, nucleic acid content, cell-specific heterotrophic activity, nanoflagellate abundance, prokaryotic to nanoflagellate abundance ratio) than in the epipelagic (i.e., bulk activity, nucleic acid content and nanoflagellate abundance) waters. Our results show that the mesopelagic realm in the NE Atlantic is, in terms of microbial activity, more heterogeneous than its epipelagic counterpart, probably linked to mesoscale hydrographical variations.

  • 56.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Arístegui, Javier
    Gasol, Josep M.
    Lekunberri, Itziar
    Herndl, Gerhard J.
    Mesoscale eddies: hot-spots for prokaryotic diversity and function in the ocean2010In: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 4, p. 975-988Article in journal (Refereed)
    Abstract [en]

    To investigate the effects of mesoscale eddies on prokaryotic assemblage structure and activity, we sampled two cyclonic eddies (CEs) and two anticyclonic eddies (AEs) in the permanent eddy-field downstream the Canary Islands. The eddy stations were compared with two far-field (FF) stations located also in the Canary Current, but outside the influence of the eddy field. The distribution of prokaryotic abundance (PA), bulk prokaryotic heterotrophic activity (PHA), various indicators of single-cell activity (such as nucleic acid content, proportion of live cells, and fraction of cells actively incorporating leucine), as well as bacterial and archaeal community structure were determined from the surface to 2000 m depth. In the upper epipelagic layer (0–200 m), the effect of eddies on the prokaryotic community was more apparent, as indicated by the higher PA, PHA, fraction of living cells, and percentage of active cells incorporating leucine within eddies than at FF stations. Prokaryotic community composition differed also between eddy and FF stations in the epipelagic layer. In the mesopelagic layer (200–1000 m), there were also significant differences in PA and PHA between eddy and FF stations, although in general, there were no clear differences in community composition or single-cell activity. The effects on prokaryotic activity and community structure were stronger in AE than CE, decreasing with depth in both types of eddies. Overall, both types of eddies show distinct community compositions (as compared with FF in the epipelagic), and represent oceanic ‘hotspots’ of prokaryotic activity (in the epi- and mesopelagic realms).

  • 57.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Arístegui, Javier
    Gasol, Josep M.
    Sintes, Eva
    van Aken, Hendrik M.
    Herndl, Gerhard J.
    High dissolved extracellular enzymatic activity in the deep Central Atlantic Ocean2010In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 58, no 3, p. 287-302Article in journal (Refereed)
    Abstract [en]

    The distribution of prokaryotic abundance (PA), prokaryotic heterotrophic production (PHP), and suspended particulate organic material (POM), as well as total and dissolved (operationally defined as passing through 0.2 mu m pore size filters) potential extracellular enzymatic activities (EEA; alpha- and beta-glucosidase [AGase and BGase], leucine aminopeptidase [LAPase], and alkaline phosphatase [APase]) were determined in the meso- and bathypelagic waters of the (sub)tropical Atlantic along an eastern zonal transatlantic transect and a western N-S transect. Significant differences between both transects were found for POM concentration but not for PA, PHP (except in the subsurface and oxygen minimum layer), and dissolved and total EEA. PHP decreased by 3 orders of magnitude from the lower euphotic zone to bathypelagic waters, while PA and cell-specific PHP decreased only by 1 and 2 orders of magnitude, respectively. The proportion of the dissolved to the total EEA was high in the dark ocean for all the enzymes, ranging from 54 to 100, 56 to 100, 65 to 100 and 57 to 97 % for AGase, BGase, LAPase and APase, respectively. The kinetic parameters (V-max, and K-m) of both the dissolved and total fractions of LAPase and APase were very similar throughout the water column, suggesting a similar origin for both dissolved and particulate EEA. Significant correlations of both dissolved and total EEA were found with prokaryotic metabolism and the POM pool. Based on the previous notion that the fraction of dissolved EEA is higher in particle-attached than in free-living microbes, our results suggest that microbial activity in the dark ocean occurs mainly on colloidal and particulate material. This is in agreement with recent genomic evidence. However, these colloidal and particulate materials are prone to disruption during the sampling process. Hence, more selective sampling techniques are needed to specifically collect these deep-water aggregates that probably represent hotspots of microbial activity in the deep ocean.

  • 58.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Arístegui, Javier
    Sintes, Eva
    Reinthaler, Thomas
    Gasol, Josep M.
    Herndl, Gerhard J.
    Significance of non-sinking particulate organic carbon and dark CO2 fixation to heterotrophic carbon demand in the mesopelagic Atlantic2010In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 37, p. L09602-Article in journal (Refereed)
    Abstract [en]

    It is generally assumed that sinking particulate organic carbon (POC) constitutes the main source of organic carbon supply to the deep ocean's food webs. However, a major discrepancy between the rates of sinking POC supply (collected with sediment traps) and the prokaryotic organic carbon demand (the total amount of carbon required to sustain the heterotrophic metabolism of the prokaryotes; i.e., production plus respiration, PCD) of deep-water communities has been consistently reported for the dark realm of the global ocean. While the amount of sinking POC flux declines exponentially with depth, the concentration of suspended, buoyant non-sinking POC (nsPOC; obtained with oceanographic bottles) exhibits only small variations with depth in the (sub) tropical Northeast Atlantic. Based on available data for the North Atlantic we show here that the sinking POC flux would contribute only 4-12% of the PCD in the mesopelagic realm (depending on the primary production rate in surface waters). The amount of nsPOC potentially available to heterotrophic prokaryotes in the mesopelagic realm can be partly replenished by dark dissolved inorganic carbon fixation contributing between 12% to 72% to the PCD daily. Taken together, there is evidence that the mesopelagic microheterotrophic biota is more dependent on the nsPOC pool than on the sinking POC supply. Hence, the enigmatic major mismatch between the organic carbon demand of the deep-water heterotrophic microbiota and the POC supply rates might be substantially smaller by including the potentially available nsPOC and its autochthonous production in oceanic carbon cycling models. Citation: Baltar, F., J. Aristegui, E. Sintes, J. M. Gasol, T. Reinthaler, and G. J. Herndl (2010), Significance of non-sinking particulate organic carbon and dark CO2 fixation to heterotrophic carbon demand in the mesopelagic northeast Atlantic.

  • 59.
    Baltar, Federico
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Lindh, Markus V.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Parparov, Arkadi
    Israel Oceanographic and Limnological Research.
    Berman, Tom
    Israel Oceanographic and Limnological Research.
    Pinhassi, Jarone
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Prokaryotic community structure and respiration during long-term incubations2012In: MicrobiologyOpen, ISSN 2045-8827, E-ISSN 2045-8827, Vol. 1, no 2, p. 214-224Article in journal (Refereed)
    Abstract [en]

    Despite the importance of incubation assays for studies inmicrobial ecology that frequentlyrequire long confinement times, few reports are available in which changesin the assemblage structure of aquatic prokaryotes were monitored during longtermincubations.We measured rates of dissolved organic carbon degradation andmicrobial respiration by consumption of dissolved oxygen (DO) in four experimentswith Lake Kinneret near-surface water and, concomitantly, we analyzed thevariability in prokaryotic community structure during long-term dark bottle incubations.During the first 24 h, therewere only minor changes in bacterial communitycomposition. Thereafter there were marked changes in the prokaryotic communitystructure during the incubations. In contrast, oxygen consumption rates (a proxyfor both respiration and dissolved organic carbon degradation rates) remained stablefor up to 10–23 days. This study is one of the first to examine closely the phylogeneticchanges that occur in the microbial community of untreated freshwaterduring long-term (days) incubations in dark, sealed containers. Novel informationon the diversity of the main bacterial phylotypes that may be involved in dissolvedorganic matter degradation in lake Kinneret is also provided. Our results suggestthat, under certain ecological settings, constant community metabolic rates can bemaintained as a result of shifts in community composition.

  • 60. Barlow, Sue
    et al.
    Schlatter, Josef
    Öberg, Tomas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Castoldi, Anna
    Court Marques, Danièle
    Cutting, Andrew
    Jacobs, Miriam
    Lahaniatis, Majlinda
    Liem, Djien
    Manini, Paola
    Mohimont, Luc
    Rortais, Agnes
    Smille, Laura
    Steinkellner, Hans
    Scientific report of the Endocrine Active Substances Task Force2010In: EFSA Journal, ISSN 1831-4732, Vol. 8, no 11, p. Article ID: 1932-Article in journal (Other academic)
    Abstract [en]

    Discussions within the Scientific Committee and the Advisory Forum have called for the development of a common approach within EFSA towards endocrine active substances. The aim of this report by an internal EFSA task force is to clarify the state-of-play, and provide recommendations for scientific and communication issues. Both specific issues and new regulations make it necessary to follow up on recent developments with the EU bodies, Member States, and internationally, in order to avoid diverging assessment approaches and the duplication of work. The proposed actions for EFSA are to contribute to the work in progress under the auspices of DG Environment and to continue its participation in the ongoing OECD activities in the area of testing of chemicals. The development of a generally accepted risk assessment methodology is an additional challenge due to the complexity of the issues involved. Here, the task force recommends that EFSA continues its activities aimed at developing harmonised methodologies for risk assessment of combined exposures to endocrine active substances in food. EFSA should continue to build a dialogue to develop a common strategy with the EC, other EU bodies, Member States’ Competent Authorities, international organisations and partners, as well as external experts and stakeholders on the before mentioned issues. In line with these recommendations, it is proposed that EFSA creates a working group of Panel experts and national experts to advise on prioritising the work on endocrine active substances. EFSA should also work with the experts in its Advisory Group on Risk Communications in conjunction with the communication experts from Member States, and continues to monitor and analyse media and stakeholder developments, in order to define a strategy for communications addressing both the collective group and specific endocrine active substances.

  • 61.
    Barshep, Yahkat
    et al.
    A.P. Leventis Ornithological Research Institute, Nigeria.
    Ottosson, Ulf
    A.P. Leventis Ornithological Research Institute, Nigeria.
    Waldenström, Jonas
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Hulme, Mark
    British Trust for Ornithology, UK.
    Non-breeding ecology of the Whinchat Saxicola rubetra in Nigeria2012In: Ornis Svecica, ISSN 1102-6812, Vol. 22, p. 25-32Article in journal (Refereed)
    Abstract [en]

    This study on the non-breeding ecology of the Whinchat Saxicola rubetra was conducted in central Nigeria from February through April. The core site was at Gwafan (N09°53', E08°57'), an open scrubland located 10 km east of the city of Jos. The density of Whinchats at Gwafan was 0.58 individuals/ha, almost three times the overall density around Jos. Time budget observations of colour banded Whinchats, including six birds fitted with radio-transmitters, showed that they spent 80% of their time perching, 11% foraging, 7% preening, and 2% flying. The main method of catching insects was a swoop to the ground. There was no change in perching, preening or flying time but the time some Whinchats spent foraging increased towards the end of the study period. GPS positions of individuals showed that all birds held clearly demarcated territories and defended them against neighbours. Aggressive interactions were also recorded between Whinchats and other bird species. Three birds colour-ringed in 2006 returned to the study site in 2007 and one occupied almost the same territory, indicating site fidelity.

  • 62.
    Basheer, Shabana
    et al.
    Central Food Technology Research Institute.
    Samyn, Dieter R.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Hedström, Martin
    Lund university.
    Thakur, Munna Singh
    Central Food Technology Research Institute.
    Persson, Bengt L.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Mattiasson, Bo
    Lund university.
    A membrane protein based biosensor: Use of a phosphate - H+ symporter membrane protein (Pho84) in the sensing of phosphate ions.2011In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 27, no 1, p. 58-63Article in journal (Refereed)
    Abstract [en]

    A label free biosensor for direct detection of inorganic phosphate based on potential-step capacitance measurements has been developed. The high-affinity Pho84 plasma membrane phosphate/proton symporter of Saccharomyces cerevisiae was used as a sensing element. Heterologously expressed and purified Pho84 protein was immobilized on a self-assembled monolayer (SAM) on a capacitance electrode. Changes in capacitance were recorded upon exposure to phosphate compared to the control substance, phosphate analogue methylphosphonate. Hence, even without the explicit use of lipid membranes, the Pho84 membrane protein could retain its capacity of selective substrate binding, with a phosphate detection limit in the range of the apparent in vivo K(m). A linear increase in capacitance was monitored in the phosphate concentration range of 5-25 mu M. The analytical response of the capacitive biosensor is in agreement with that the transporter undergoes significant conformational changes upon exposure to inorganic phosphate, while exposure to the analogue only causes minor responses.

  • 63.
    Baskaran, Karthikeyan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Optimal Use of Peripheral Vision2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    People who lose their central vision have to rely on their peripheral vision for all visual tasks. The ability to resolve fine details in the periphery is reduced due to retinal limitations and the optical aberrations arising from the use of off-axis vision. The aim of this work is to improve vision by enhancing the image quality at the preferred retinal locus by means of correcting the optical errors. The focus of this thesis has been to measure and correct peripheral optical errors, as well as to evaluate their impact on resolution acuity in both normal and central visual field loss subjects.

     In order to measure peripheral optics we employed a COAS HD VR open view aberrometer which is based on the Hartmann-Shack principle. Psychophysical methods were used to evaluate peripheral grating resolution acuity. We assessed the repeatability of the wavefront sensor in measuring the peripheral ocular aberrations. The symmetry of peripheral ocular aberrations between the left and right eyes was examined. The influence of age on peripheral ocular aberrations was also investigated. We evaluated peripheral vision with sphero-cylindrical correction in healthy eyes and performed the first adaptive optics aberration correction at the preferred retinal locus of a single central visual field loss subject.

     We found that the aberrometer was repeatable and reliable in measuring peripheral ocular aberrations. There was mirror symmetry between the two eyes for most of the peripheral aberration coefficients. Age had a significant influence on peripheral ocular aberrations; there were larger amounts of higher-order aberrations in old eyes than in young eyes. Peripheral low contrast resolution acuity improved with peripheral refractive correction in subjects who had higher amounts of off-axis astigmatism. Finally, adaptive optics aberration correction improved both high and low contrast resolution acuity measured at the preferred retinal locus of the single low vision subject.

     Because of their versatility, open view aberrometers will hopefully be a standard clinical instrument at low vision clinics as they allow for measurements to be rapidly performed at any location in the visual field. The existence of off-axis astigmatism should be better communicated within the low-vision rehabilitation community. Currently, the off-axis refractive errors can be corrected with conventional methods and we hope that the higher-order aberrations can also be corrected in a more realistic ways in the future.  

     In conclusion, this thesis has shown that peripheral visual function can be improved by optical correction. The findings of this thesis have broadened the knowledge of peripheral optical errors and their influence on vision.

  • 64.
    Baskaran, Karthikeyan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Lewis, Peter
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rosen, Robert
    Biomedical and X-Ray Physics.
    Unsbo, Peter
    Biomedical and X-Ray Physics.
    Gustafsson, Jörgen
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Effects of Optical Defocus on Resolution Acuity in Preferred Retinal Locus2011In: Invest Ophthalmol Vis Sci 2011;52: E-Abstract 1900., 2011, Vol. 52, no 6Conference paper (Refereed)
    Abstract [en]

    PurposeResolution acuity in the peripheral visual field is primarily limited by retinal sampling. In healthy eyes, the correction of peripheral refractive errors does not produce significant visual benefits other than improved detection and low contrast acuity. However, studies (Lundstrom L et al, Optom Vis Sci, 2007;84:1046-52) have shown that peripheral refractive corrections improve resolution acuity in subjects with central visual field loss (CFL) who have an established preferred retinal locus (PRL). The aim of this study was to evaluate the effect of optical defocus on high contrast resolution acuity in the PRL. MethodsResolution acuity was evaluated under spherical defocus in the PRL of three low vision subjects (mean age 75 years) with long standing CFL (due to age-related macular degeneration). Off-axis refractive error at the PRL was measured by an open-field COAS-HD VR aberrometer and was corrected accordingly. The PRL for subject 1 was located at 10{degrees} in the temporal visual field (left eye), subject 2 at 20{degrees} in the nasal visual field (right eye) and subject 3 at 15{degrees} in the inferior visual field (left eye). Stimuli consisting of high-contrast Gabor patches with a visible diameter of 3{o} were presented on a CRT monitor situated 1.0 meter from the subject. Resolution thresholds for static visual acuity (SVA) and dynamic visual acuity (DVA) were obtained using an adaptive Bayesian algorithm. Fixation was aided using illuminated concentric rings covering {+/-}25{degrees} in the visual field. Defocus was altered in 1D steps up to {+/-}4D. When measuring DVA, the sine-wave gratings drifted within the Gaussian envelope at an angular velocity of 1{degrees}/sec. ResultsResolution thresholds for both SVA and DVA in the PRL varied significantly with the amount of optical defocus. The results show a 2 - 3 line decrease (logMAR) in SVA and DVA with 4 D positive and negative defocus. There was no significant difference between SVA and DVA with increasing defocus. In the absence of defocus, SVA was significantly better than DVA in the PRL. ConclusionsDefocus as low as one dioptre has an impact on both static and dynamic high contrast resolution acuity for CFL subjects using a PRL. The results of this study suggest that, for CFL subjects using a PRL, resolution acuity is not only sampling limited but also influenced by the optics of the eye.

  • 65.
    Baskaran, Karthikeyan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rosen, R.
    Lewis, Peter
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Unsbo, P.
    Gustafsson, Jörgen
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Benefit of Adaptive Optics Aberration Correction at Preferred Retinal Locus2012In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 89, no 9, p. 1417-1423Article in journal (Refereed)
    Abstract [en]

    PURPOSE.: To investigate the effect of eccentric refractive correction and full aberration correction on both high- and low-contrast grating resolution at the preferred retinal locus (PRL) of a single low-vision subject with a long-standing central scotoma. METHODS.: The subject was a 68-year-old women with bilateral absolute central scotoma due to Stargardt disease. She developed a single PRL located 25 degrees nasally of the damaged macula in her left eye, this being the better of the two eyes. High- (100%) and low-contrast (25 and 10%) grating resolution acuity was evaluated using four different correction conditions. The first two corrections were solely refractive error corrections, namely, habitual spectacle correction and full spherocylindrical correction. The latter two corrections were two versions of adaptive optics corrections of all aberrations, namely, habitual spectacle correction with aberration correction and full spherocylindrical refractive correction with aberration correction. RESULTS.: The mean high-contrast (100%) resolution acuity with her habitual correction was 1.06 logMAR, which improved to 1.00 logMAR with full spherocylindrical correction. Under the same conditions, low-contrast (25%) acuity improved from 1.30 to 1.14 logMAR. With adaptive optics aberration correction, the high-contrast resolution acuities improved to 0.89/0.92 logMAR and the low-contrast acuities improved to 1.04/1.06 logMAR under both correction modalities. The low-contrast (10%) resolution acuity was 1.34 logMAR with adaptive optics aberration correction; however, with purely refractive error corrections, she was unable to identify the orientation of the gratings. CONCLUSIONS.: Correction of all aberrations using adaptive optics improves both high- and low-contrast resolution acuity at the PRL of a single low-vision subject with long-standing absolute central scotoma

  • 66.
    Baskaran, Karthikeyan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Theagarayan, Baskar
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Carius, Staffan
    Linnaeus University, Faculty of Science and Engineering, School of Computer Science, Physics and Mathematics.
    Gustafsson, Jörgen
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Influence of age on peripheral aberration2010Conference paper (Refereed)
    Abstract [en]

    The purpose of this study is to compare peripheral higher order aberrations in young

    and old emmetropic eyes across the horizontal (±40°) and inferior (–20°) visual field.

    Introduction

     

     

    People with central visual field loss use eccentric fixation for various visual tasks.

    Recently studies have shown that the correction of lower order aberrations (defocus &

    astigmatism) can improve eccentric vision in subjects with central visual field loss

    (CFL)[1]. The CFL subjects mostly correspond to older age groups who use eccentric

    fixation angles up to 20°–30°. While there have been studies comparing the off-axis

    lower order aberrations in normal young and old subjects[2], there is only one recent

    study, which has compared off-axis higher order aberrations in normal young and old

    emmetropic eyes up to 20° (horizontal and vertical) eccentricity[3]. In this study we

    have measured off-axis aberrations in a group of 10 young (23 ± 3 years) and 10 old

    (57 ± 4 years) emmetropes. The aberrations of the right eye were measured using

    COAS-HD VR Hartmann-Shack aberrometer in steps 10° out to ± 40° horizontally and

    –20° inferiorly in the visual field. Subjects rotated the eyes to view the fixation targets,

    which were red light emitting diodes, placed at 3 meter from the eye. The aberrations

    were quantified for a pupil area 5 mm in diameter.

    Discussion

     

     

    Mixed between-within subject’s analysis of variance of the horizontal coma C13

    showed that there was a statistically significant difference between age groups

    (p<0.05). The coma increased linearly in both groups from nasal to temporal visual

    field. The rate of change was greater in the old (slope = –0.027 μm/deg) compared

    to the young (slope = –0.012 μm/deg) emmetropes. In the inferior visual field,

    vertical coma C-13 changed linearly in both groups with higher values in old (slope =

    0.015 μm/deg) compared to young (slope = 0.006 μm/deg). The mean spherical

    aberration was positive in older emmetropes (0.053 μm) compared to young

    emmetropes (-0.030 μm). The HO RMS showed a quadratic increase in the

    periphery for both age groups. The HO RMS was greater in older emmetropes but it

    was not statistically significant (p>0.05) when compared to young emmetropes.

     

    Conclusions

     

     

    Our results show that there is an increase in coma, spherical aberration, and HO

    RMS with age in the periphery.

  • 67.
    Baskaran, Karthikeyan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Theagarayan, Baskar
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Carius, Staffan
    Linnaeus University, Faculty of Science and Engineering, School of Computer Science, Physics and Mathematics.
    Gustafsson, Jörgen
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Measurement of Off-axis Refraction with a Commercial Open Field Aberrometer2010Conference paper (Refereed)
    Abstract [en]

    Purpose:

    People with central visual field loss (CFL) use their remaining peripheral vision in order to see better when performing various visual related tasks. At large off-axis angles, the eccentric vision can be limited both by the low resolution capacity of the peripheral retina and by the optical aberrations caused due to oblique angles. Previous work has shown that eccentric correction of induced off-axis astigmatism can improve vision in a preferred retinal location (PRL) for people with CFL. However, the eccentric refraction is often difficult to determine with traditional refractive methods. This work therefore shows the use of a commercially available wavefront sensor to measure fast and reliable off-axis refraction. Data on off-axis refraction is also of interest in the field of myopia research.

    Methods:

    We used the new open-field high-definition complete ophthalmic analysis system, COAS HD -VR, to evaluate off-axis refraction. Using the special Vision Research tool in this system stimulus (fixation objects) can be presented in a large part of the visual field. The instrument can measure out to 40 degrees in the horizontal visual field and 20 degrees in the vertical visual field with a range from sphere +7 D to − 17 D. It measures astigmatism up to 10 D. This instrument also allows natural binocular viewing without obstacles. Aberrations of the right eye of 30 emmetropes (24 ± 4 years) were studied. Off-axis refraction and higher order (HO) aberrations were measured in steps of 10° out to ± 30° in the horizontal visual field

    Results:

    The first data on young emmetropic eyes with this new instrument showed promising results for low (LO) and higher order (HO) aberrations in the peripheral visual field. Of the LO aberrations, astigmatism increased significantly with the off–axis angle, from 0.25 D at 10° Nasal to 1.65 D at 30° Nasal. In the HO aberrations, coma (C13) showed a linear increase across the horizontal visual field (p < 0.05)

    Conclusions:

    The COAS HD-VR shows promising results and good usability for future research in evaluation of off-axis refraction. In future we believe the aberrometer can be used clinically to measure off-axis refractions in low vision patients.

  • 68.
    Baskaran, Karthikeyan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Theagarayan, Baskar
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Carius, Staffan
    Linnaeus University, Faculty of Science and Engineering, School of Computer Science, Physics and Mathematics.
    Gustafsson, Jörgen
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Ocular Aberrations in the Peripheral Visual Field With a Commercial Open-View Aberrometer2010In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 51, no 5, article id 3951Article in journal (Refereed)
    Abstract [en]

    PurposeThe interest in off-axis aberrations has increased with the discovery of a possible link between myopia development and peripheral optics. The most common technology to measure the off-axis aberrations is a Shack-Hartmann wavefront aberrometer. This is the first study to report peripheral aberrations in a large sample of emmetropic population with a commercial open-view Shack-Hartmann aberrometer. MethodsThe commercial open-view Shack-Hartmann aberrometer COAS-HD VR was used to measure the aberrations in the peripheral vision. Aberrations of the right eye of 30 emmetropes (24 {+/-} 4 years) were studied. Off-axis aberrations were measured in steps of 10{degrees} out to {+/-} 30{degrees} in the horizontal visual field. The subjects turned their eye to view the off-axis fixation target (light emitting diode placed at 3 meters) during the measurement. The resulting wavefront aberrations were parameterized with Zernike coefficients for a 5 mm diameter pupil. All analyzes are reported according to optical society of America (OSA) recommended standards. ResultsAberrations from the 2nd to 6th order and the total higher-order root-mean-square (HO RMS) were analyzed using one-way ANOVA. The defocus C02 was significantly myopic in the nasal visual field (+20{degrees}, +30{degrees}) whereas there was no significant difference in the temporal visual field. Astigmatism C22 increased quadratically from {+/-}10{degrees} in the periphery and coma C13 showed a linear increase across the horizontal visual field (p < 0.05). The spherical aberration C04 and the total HO RMS showed a significant change at {+/-}30o. ConclusionsOur results showed that in young emmetropes there was a significant increase of HO RMS at {+/-}30{degrees}, which is expected. Astigmatism, horizontal coma, and spherical aberration vary systematically across the horizontal visual field in agreement with Seidel theory. The findings of our study with a large sample of emmetropic population agree with the previous studies done with laboratory built aberrometers.

  • 69.
    Baskaran, Karthikeyan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Theagarayan, Baskar
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Carius, Staffan
    Linnaeus University, Faculty of Science and Engineering, School of Computer Science, Physics and Mathematics.
    Gustafsson, Jörgen
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Repeatability of Peripheral Aberrations in Young Emmetropes2010In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 87, no 10, p. 751-759Article in journal (Refereed)
    Abstract [en]

    PURPOSE.: The purpose of this study is to assess the intrasession repeatability of ocular aberration measurements in the peripheral visual field with a commercially available Shack-Hartmann aberrometer (complete ophthalmic analysis system-high definition-vision research). The higher-order off-axis aberrations data in young healthy emmetropic eyes are also reported.

    METHODS.: The aberrations of the right eye of 18 emmetropes were measured using an aberrometer with an open field of view that allows peripheral measurements. Five repeated measures of ocular aberrations were obtained and assessed in steps of 10 degrees out to +/-40 degrees in the horizontal visual field (nasal + and temporal -) and -20 degrees in the inferior visual field. The coefficient of repeatability, coefficient of variation, and the intraclass correlation coefficient were calculated as a measure of intrasession repeatability.

    RESULTS.: In all eccentric angles, the repeatability of the third- and fourth-order aberrations was better than the fifth and sixth order aberrations. The coefficient of variation was <30% and the intraclass correlation coefficient was >0.90 for the third and fourth order but reduced gradually for higher orders. There was no statistical significant difference in variance of total higher-order root mean square between on- and off-axis measurements (p > 0.05). The aberration data in this group of young emmetropes showed that the horizontal coma (C13) was most positive at 40 degrees in the temporal field, decreasing linearly toward negative values with increasing off-axis angle into the nasal field, whereas all other higher-order aberrations showed little or no change.

    CONCLUSIONS.: The complete ophthalmic analysis system-high definition-vision research provides fast, repeatable, and valid peripheral aberration measurements and can be used efficiently to measure off-axis aberrations in the peripheral visual field

  • 70.
    Baskaran, Karthikeyan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Unsbo, Peter
    Biomedical and X-Ray Physics.
    Gustafsson, Jörgen
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Influence of age on peripheral ocular aberrations.2011In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 88, no 9, p. 1088-1098Article in journal (Refereed)
    Abstract [en]

    PURPOSE.: To compare peripheral lower and higher order aberrations across the horizontal (±40°) and inferior (-20°) visual fields in healthy groups of young and old emmetropes. METHODS.: We have measured off-axis aberrations in the groups of 30 younger (24 ± 3 years) and 30 older (58 ± 5 years) emmetropes. The aberrations of OD were measured using the COAS-HD VR Shack-Hartmann aberrometer in 10° steps to ±40° horizontally and -20° inferiorly in the visual field. The aberrations were quantified with Zernike polynomials for a 4 mm pupil diameter. The second-order aberration coefficients were converted to their respective refraction components (M, J45, and J180). Mixed between-within subjects, analysis of variance were used to determine whether there were significant differences in the refraction and aberration components for the between-subjects variable age and the within-subjects variable eccentricity. RESULTS.: Peripheral refraction components were similar in both age groups. Among the higher order coefficients, horizontal coma (C3) and spherical aberration (C4) varied mostly between the groups. Coma increased linearly with eccentricity, at a more rapid rate in the older group than in the younger group. Spherical aberration was more positive in the older group compared with the younger group. Higher order root mean square increased more rapidly with eccentricity in the older group. CONCLUSIONS.: Like the axial higher order aberrations, the peripheral higher order aberrations of emmetropes increase with age, particularly coma and spherical aberration.

  • 71.
    Berg, Christer
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Ekedahl, Anders
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Dosages involving split tablets - common but unnecessary?2010In: Journal of Pharmaceutical Health Services Research, ISSN 1759-8885, Vol. 1, no 3, p. 137-141Article in journal (Refereed)
  • 72.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Gustafsson, Jon Petter
    Kungliga Tekniska Högskolan, Skolan för arkitektur och samhällsbyggnad (ABE), Institutionen för hållbar utveckling, miljövetenskap och teknik (SEED).
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Aluminium speciation in boreal catchments enriched in fluoride2012Conference paper (Other academic)
  • 73.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Peltola, Pasi
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Drake, Henrik
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Fluoride patterns in a boreal stream influenced by bedrock and hydrology2011In: Goldschmidt Conference Abstracts 2011. Mineralogical Magazine, Vol. 75 (3), 2011, p. 517-517Conference paper (Refereed)
  • 74.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Peltola, Pasi
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Drake, Henrik
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Impact of a Fluorine-Rich Granite Intrusion on Levels and Distribution of Fluoride in a Small Boreal Catchment2012In: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 18, no 2, p. 77-94Article in journal (Refereed)
    Abstract [en]

    This paper explores the influence of a fluorine-rich granite on fluoride concentration in a small boreal catchment in northern Europe. The materials include stream water and shallow groundwater sampled in spatial and temporal dimensions, and analytical data on fluoride and a number of ancillary variables. Fluoride increased strongly towards the lower reaches of the catchment—at the stream outlet the concentrations were up to 4.2 mg L −1 and 1.6–4.7 times higher than upstream. Additionally, fluoride concentrations were particularly high in groundwater and small surface-water bodies (including quarries) above or in direct contact with the granite and showed a strong inverse correlation with water discharge in the stream. Taken together, these data and patterns pin-point the granite intrusion as the ultimate source, explaining the abundance and distribution of dissolved fluoride within the catchment. The granite most likely deliver fluoride to the stream by three mechanisms: (1) weathering of the fine fraction of glacial deposits, derived from the granite and associated fluorine-rich greisen alterations, (2) large relative input of baseflow, partially originating in the granite and greisen, into the lower reaches during low flow in particular, and (3) water-conducting fractures or fracture zones running through the fluorine-rich granite and greisen.

  • 75.
    Berger, Tobias
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Mats E.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Peltola, Pasi
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Drake, Henrik
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    High fluoride concentrations in surface water: example from a catchment in SE Sweden2010In: Abstract Volume of COST Action 637- METEAU 4th International Conference. Kristianstad, Sweden, October 13-15, 2010. / [ed] Bhattacharya, P., Sandhi, A. and Rosborg, I., Stockholm: Department of Land and Water Resources Engineering, Royal Institute of Technology , 2010, p. 80-81Conference paper (Other academic)
  • 76.
    Berggren, Hanna
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Genetic Wing Polymorphism in the Pygmy Grasshopper, Tetrix subulata : An Ecological and Behavioural Perspective2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Wing polymorphism in insects provides a good model system for investigating ecology and evolution of dispersal and dispersal enhancing traits. This study explores ecological, behavioural and evolutionary aspects of wing polymorphism in the pygmy grasshopper Tetrix subulata (Linnaeus, 1758) (Tetrigidae: Orthoptera). I demonstrate that there is discrete variation in wing and pronotum length among individuals within natural populations of T. subulata. Performance trials and behavioural observations indicate that the variation in wing length has important functional consequences, and that flying behaviour and propensity to fly differ according to environment (such as hostile or benign). Mother-offspring resemblance studies indicate that the discrete wing polymorphism in T. subulata has a heritable genetic component, so that an evolutionary response to selection is possible. Analyses of wild caught individuals show considerable variation in the incidence of the long winged macropterous morph among populations as well as between years within populations. Common garden experiments confirm that the differences among populations were genetically based. Hence, the variation within and among populations probably reflect evolutionary modifications driven by different selection pressures in different populations, rather than stochastic events or developmental plasticity. Flight ability provides benefits like the means of leaving unfavourable habitats and exploiting new habitats – resulting in gene flow and extended ranges. On the other hand, flight ability may be energy demanding and costly. It has been hypothesized that wing polymorphism may be maintained in part by a trade-off between flight ability and reproductive capacity. However, comparisons of number of hatchlings produced by long versus short winged wild caught females provided no firm support for this hypothesis. Results instead suggest that wing polymorphism in T. subulata may be maintained by divergent selection in different populations in combination with gene flow between populations.

  • 77.
    Berggren, Hanna
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Tinnert, Jon
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Forsman, Anders
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Spatial sorting may explain evolutionary dynamics of wing polymorphism in pygmy grasshoppers.2012In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, no 10, p. 2126-2138Article in journal (Refereed)
    Abstract [en]

    Wing polymorphism in insects provides a good model system for investigating evolutionary dynamics and population divergence in dispersal-enhancing traits. This study investigates the contribution of divergent selection, trade-offs, behaviour and spatial sorting to the evolutionary dynamics of wing polymorphism in the pygmy grasshopper Tetrix subulata (Tetrigidae: Orthoptera). We use data for > 2800 wild-caught individuals from 13 populations and demonstrate that the incidence of the long-winged (macropterous) morph is higher and changes faster between years in disturbed habitats characterized by succession than in stable habitats. Common garden and mother-offspring resemblance studies indicate that variation among populations and families is genetically determined and not influenced to any important degree by developmental plasticity in response to maternal condition, rearing density or individual growth rate. Performance trials show that only the macropterous morph is capable of flight and that propensity to fly differs according to environment. Markrecapture data reveal no difference in the distance moved between free-ranging long- and short-winged individuals. There is no consistent difference across populations and years in number of hatchlings produced by long- and shorter-winged females. Our findings suggest that the variable frequency of the long-winged morph among and within pygmy grasshopper populations may reflect evolutionary modifications driven by spatial sorting due to phenotype- and habitat typedependent emigration and immigration.

  • 78.
    Berglund Pilgrim, Caroline
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Near Point of Convergence: A Comparison of Four Different Target types2010Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Purpose: The purpose of this study was to determine if there were any differences between four different target types when measuring the near point of convergence in adults.

    Methods and Material: The near point of convergence was measured in 35 subjects with a visual acuity of at least 1.0 (6/6) in each eye and without any strabismus. The targets used were: the tip of a pen, an accommodative target, the RAF line target and a penlight viewed through red-green filters. Both break and recovery points were assessed for the different techniques. Each target was used twice in consecutive order. The line target from RAF ruler was copied on to a small plastic ruler in order to be able to use the same ruler for measuring the results. All subjects were fitted with their best correction in the trial frame after a complete refraction. The measurements were taken to the nearest 0.25cm.

    Results: There was no difference found between NPC break values for the different target types in the control group. The NPC values were found to be 5.0/7.4 in the control group and 10.8/18.2 in the anomalous group. The accommodative target was found to give more remote values (11.5cm) than expected in comparison to the other targets in the anomalous group.

    Conclusion: In patients with normal NPC, the measurements can be taken with line target or Acc. target. Patients with receded NPC values should be evaluated with penlight and red-green glasses or at least twice with the tip of a pen. 

  • 79.
    Bergman, Agneta
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Människan, kalven eller gödselbrunnen? Mjölkens destination och fördelning - hos mjölkbonden2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A variety of food is produced and passes the whole chain by processing, transport and trade and finally it ends up with the consumer. But in many cases, the food is disposed before it is eaten. Some of the produced food does not even pass the whole entire chain before it turns to waste. The question about food waste in debates is a case of access to food for every human beeing. It is question of consumption of the resources, waste management and an issue of environmental impact. Measurable statistics can be found in the later stages of the chain, but the basis for the quantities that may be one of the primary production is not as clear. My object of this thesis has been to acquire knowledge about where the milk ends up at the farm. How much is direct food for humans, how much are destined for processing, how much goes back into production - to the calves, and how large proportion becomes waste that is converted into manure. I also wanted to know the causes of why the milk ends up where it actually does. After visiting 17 dairy farms in Bohuslän, Dalsland and Västra Götaland, and through discussions with involved farmers I have found that the milk that turns into manure are collectively less than 1% of the produced milk. The main reason why the milk in the daily production goes into manure heap from the farmers I have visited, is because of the cows that are sick with mastitis or lameness, and their following penicillin therapy makes the milk become contaminated. 3% of the produced milk is essential for the future, when it goes directly to the calves. The entire 97% is produced and reaches the goal with the dairy farmer's entire business - it goes further as a potential food for humans.

  • 80.
    Bergman, Ingrid-Maria
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Polymorphism in pattern recognition receptor genes in pigs2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The mammalian immune defense consists of two systems, which are interconnected and co-operate to provide host defense. The innate immune system is always active and detects and responds to non-self without delay. The adaptive immune system has a lag phase, but is more specific and has got a memory.

    The innate immune system relies on pattern recognition receptors (PRRs) to detect molecular patterns signaling microbial presence. This thesis focuses on a centrally placed family of PRRs, namely the Toll-like receptors (TLRs), and on mannan-binding lectin (MBL), a PRR which initiates the lectin activation pathway of complement. TLRs are expressed on the cell surface and in intracellular compartments, while MBL is a soluble protein present in most body fluids.

    Polymorphism – literally ’many forms’ – refers to variation between individuals, at DNA level as well as in traits. A single nucleotide polymorphism (SNP) implicates that alternative nucleotides are present at a particular position in the genome. Mutations, together with phenomena like gene duplication and whole genome duplication, are the ultimate source of variation in nature and the fuel for evolution. Through natural selection and breeding, i.e. artificial selection, species are shaped and change over time.

    Domestic animals are well suited for genetic studies, since they enable comparisons of populations exposed to different selection criteria and environmental challenges. Also, in the case of pigs, comparisons to the wild ancestor – i.e. the wild boar – can shed light on the evolutionary process. Moreover, pigs are large animal models for humans.

    Paper I reports the refinement of previously identified quantitative trait loci for immune-related traits on pig chromosome 8.

    Papers II and III report differences in polymorphic patterns between wild boars and domestic pigs in the TLR1, TLR2, TLR6, and TLR10 genes. In TLR1 and TLR2, more SNPs were present in the domestic pigs than in the wild boars. In TLR6, SNP numbers were similar in both animal groups, but the level of heterozygosity was higher in the domestic pigs than in the wild boars. In TLR10, again, more SNPs were present in the domestic pigs, and a higher number of non-synonymous SNPs was detected in TLR10 compared to the other genes. This might suggest redundancy for TLR10 in pigs.

    Paper IV reports the presence of an SNP, previously detected in domestic pigs and assumed to affect MBL concentrations in serum, in European wild boars. Also, the connection between the presumed low-producing allele and low MBL concentration in serum was confirmed. Moreover, a novel SNP, with potential to be functionally important, was detected.

    Owing to the domestication process and differences in selection pressure, differences in polymorphic patterns between wild boars and domestic pigs are not surprising. However, since breeding means choosing among genotypes, the opposite pattern – more SNPs in wild boars than in domestic pigs – would have been expected. However, the result confirms other studies, which have shown that European wild boars went through a bottle neck before domestication started. The higher number of SNPs in domestic pigs may be due to relaxed purifying selection during the domestication process.

  • 81.
    Bergman, Ingrid-Maria
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Toll-like receptors (TLRs) and mannan-binding lectin (MBL): On constant alert in a hostile environment2011In: Upsala Journal of Medical Sciences, ISSN 0300-9734, E-ISSN 2000-1967, Vol. 116, no 2, p. 90-99Article, review/survey (Refereed)
    Abstract [en]

    In the beginning were neither B cells nor T cells nor antibodies, but innate immune defense alone. The primary functional theme of innate immunity is the distinction between self and non-self, which is maintained by a vast number of cellular and subcellular components. In this context, the immense importance of the Toll-like receptors (TLRs) is well established. Positive (Darwinian) selection seems to be acting on the ligand-binding domains of these molecules, suggesting a selection pattern similar to that previously observed in the MHC proteins. In sharp contrast to TLRs, the biological significance of mannan-binding lectin (MBL) is controversial, and, concerning humans, it has been suggested that low concentration of MBL in serum represents a selective advantage. In this mini-review, based on a doctoral thesis, evolutionary aspects of TLRs and MBL are discussed.

  • 82.
    Bergman, Ingrid-Maria
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Edman, Kjell
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nilsson Ekdahl, Kristina
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences. Uppsala University.
    Rosengren, K. Johan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences. The University of Queensland, Australia.
    Edfors, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Extensive polymorphism in the porcine Toll-like receptor 10 gene2012In: International Journal of Immunogenetics, ISSN 1744-3121, E-ISSN 1744-313X, Vol. 39, no 1, p. 68-76Article in journal (Refereed)
    Abstract [en]

    The great importance of the Toll-like receptors (TLRs) in innate immunity is well established, but one family member – TLR10 – remains elusive. TLR10 is expressed in various tissues in several species, but its ligand is not known and its function is still poorly understood. The open reading frame of TLR10 was sequenced in 15 wild boars, representing three populations, and in 15 unrelated domestic pigs of Hampshire, Landrace and Large White origin. Amino acid positions corresponding to detected nonsynonymous single nucleotide polymorphisms (SNPs) were analysed in the crystal structures determined for the human TLR1–TLR2–lipopeptide complex and the human TLR10 Toll/Interleukin 1 receptor (TIR) dimer. SNP occurrence in wild boars and domestic pigs was compared, and haplotypes for the TLR10 gene and the TLR6-1-10 gene cluster were reconstructed. Despite the limited number of animals sequenced in the present study (N = 30), a larger number of SNPs were found in TLR10 than recently reported for TLR1, TLR6 and TLR2. Thirty-three SNPs were detected, of which 20 were nonsynonymous. The relative frequency of nonsynonymous (dN) and synonymous (dS) SNPs between wild boars and domestic pigs was higher in TLR10 than recently reported for TLR1, TLR6 and TLR2. However, the polymorphism reported in the present study seems to leave the function of the TLR10 molecule unaffected. Furthermore, no nonsynonymous SNPs were detected in the part of the gene corresponding to the hinge region of the receptor, probably reflecting rigorously acting functional constraint. The total number of SNPs and the number of nonsynonymous SNPs were significantly lower (< 0.05) in the wild boars than in the domestic pigs, and fewer TLR10 haplotypes were present in the wild boars. The majority of the TLR6-1-10 haplotypes were specific for either wild boars or domestic pigs, probably reflecting differences in microbial environment and population history.

  • 83.
    Bergman, Ingrid-Maria
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Edman, Kjell
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rosengren, K. Johan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Edfors, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    European wild boars and domestic pigs display different polymorphic patterns in the Toll-like receptor (TLR)1, TLR2, TLR6, and TLR10 genes.2010In: International Symposium on Animal Genomics for Animal Health Paris, France, 31 May – 2 June 2010: The AGAH 2010 Abstract Book, 2010, p. 35-Conference paper (Other academic)
    Abstract [en]

    The Toll-like receptors (TLR) are vitally important pattern recognition receptors linking innate and adaptive immunity. Several single nucleotide polymorphisms (SNP) in human TLR genes have been associated with disease. There are few studies on associations between polymorphisms in TLR genes and disease in pigs, but the TLR2/TLR6 heterodimer is activated by Mycoplasma hyopneumoniae, and the expression of TLR2, TLR4, and TLR9 is modulated in the presence of different Salmonella serovars. Porcine TLR1, TLR6, and TLR10 are located in a cluster on the p arm of chromosome 8, while TLR2 resides on the q arm. Previously, we identified quantitative trait loci (QTL) for immune-related traits on pig chromosome 8, close to the KIT gene and the microsatellite S0225, respectively. In order to explore polymorphism in some TLR genes in European wild boars and domestic pigs, TLR1, TLR2, and TLR6 were sequenced in 25 wild boars, representing three populations, and in 15 domestic pigs of Hampshire, Landrace, and Large White origin. Similarly, TLR10 was sequenced in 15 wild boars and 15 domestic pigs. In TLR1 and TLR2, more SNP were present in the domestic pigs than in the wild boars. In TLR6, SNP numbers were similar in both animal groups, but the level of heterozygosity was higher in the domestic pigs than in the wild boars. In TLR10, again, more SNP were present in the domestic pigs, and a higher number of nonsynonymous SNP were detected in TLR10 compared to the other genes. This may suggest redundancy for TLR10 in pigs. 

  • 84.
    Bergman, Ingrid-Maria
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rosengren, K. Johan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Edman, Kjell
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Edfors, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    European wild boars and domestic pigs display different polymorphic patterns in the Toll-like receptor (TLR) 1, TLR2, and TLR6 genes2010In: Immunogenetics, ISSN 0093-7711, E-ISSN 1432-1211, Vol. 62, no 1, p. 49-58Article in journal (Refereed)
    Abstract [en]

    During the last decade, the Toll-like receptors (TLRs) have been extensively studied and their immense importance in innate immunity is now being unveiled. Here, we report pronounced differences – probably reflecting the domestication process and differences in selective pressure – between wild boars and domestic pigs regarding single nucleotide polymorphisms (SNPs) in TLR genes. The open reading frames of TLR1, TLR2, and TLR6 were sequenced in 25 wild boars, representing three populations, and in 15 unrelated domestic pigs of Hampshire, Landrace, and Large White origin. In total, 20, 27, and 26 SNPs were detected in TLR1, TLR2, and TLR6, respectively. In TLR1 and TLR2, the numbers of SNPs detected were significantly lower (P ≤ 0.05, P ≤ 0.01) in the wild boars than in the domestic pigs. In the wild boars, one major high frequency haplotype was found in all three genes, while the same pattern was exhibited only by TLR2 in the domestic pigs. The relative frequency of non-synonymous (dN) and synonymous (dS) SNPs was lower for the wild boars than for the domestic pigs in all three genes. In addition, differences in diversity between the genes were revealed: the mean heterozygosity at the polymorphic positions was markedly lower in TLR2 than in TLR1 and TLR6. Because of its localization – in proximity of the bound ligand – one of the non-synonymous SNPs detected in TLR6 may represent species-specific function on the protein level. Furthermore, the codon usage pattern in the genes studied deviated from the general codon usage pattern in Sus scrofa.

  • 85.
    Bergman, Ingrid-Maria
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Sandholm, Kerstin
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Juul-Madsen, Helle R.
    Heegaard, Peter M.
    Nilsson Ekdahl, Kristina
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Edfors, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    MBL-A concentrations and MBL1 genotypes in European wild boars, Large White pigs, and wild boar/Large White crossbreds2010In: 8th European Colloquium on Acute Phase Proteins in Helsinki, 2010.08.25-2010.08.27, 2010, p. 25-26Conference paper (Refereed)
  • 86.
    Bergqvist, Petronella
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Towards novel therapies and diagnostics: Studies of a novel polymer system2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 87. Bergsten, Johannes
    et al.
    Bilton, David T.
    Fujisawa, Tomochika
    Elliott, Miranda
    Monaghan, Michael T.
    Balke, Michael
    Hendrich, Lars
    Geijer, Joja
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Foster, Garth N.
    Ribera, Ignacio
    Nilsson, Anders N.
    Barraclough, Timothy G.
    Vogler, Alfried P.
    The Effect of Geographical Scale of Sampling on DNA Barcoding2012In: Systematic Biology, ISSN 1063-5157, E-ISSN 1076-836X, Vol. 61, no 5, p. 851-869Article in journal (Refereed)
    Abstract [en]

    Eight years after DNA barcoding was formally proposed on a large scale, CO1 sequences are rapidly accumulating from around the world. While studies to date have mostly targeted local or regional species assemblages, the recent launch of the global iBOL project (International Barcode of Life), highlights the need to understand the effects of geographical scale on Barcoding's goals. Sampling has been central in the debate on DNA Barcoding, but the effect of the geographical scale of sampling has not yet been thoroughly and explicitly tested with empirical data. Here, we present a CO1 data set of aquatic predaceous diving beetles of the tribe Agabini, sampled throughout Europe, and use it to investigate how the geographic scale of sampling affects 1) the estimated intraspecific variation of species, 2) the genetic distance to the most closely related heterospecific, 3) the ratio of intraspecific and interspecific variation, 4) the frequency of taxonomically recognized species found to be monophyletic, and 5) query identification performance based on 6 different species assignment methods. Intraspecific variation was significantly correlated with the geographical scale of sampling (R-square = 0.7), and more than half of the species with 10 or more sampled individuals (N = 29) showed higher intraspecific variation than 1%, sequence divergence. In contrast, the distance to the closest heterospecific showed a significant decrease with increasing geographical scale of sampling. The average genetic distance dropped from >7% for samples within 1 km, to <3.5% for samples up to >6000 km apart. Over a third of the species were not monophyletic, and the proportion increased through locally, nationally, regionally, and continentally restricted subsets of the data. The success of identifying queries decreased with increasing spatial scale of sampling; liberal methods declined from 100% to around 90%, whereas strict methods dropped to below 50% at continental scales. The proportion of query, identifications considered uncertain (more than one species <1% distance from query) escalated from zero at local, to 50% at continental scale. Finally, by resampling the most widely sampled species we show that even if samples are collected to maximize the geographical coverage, up to 70 individuals are required to sample 95%, of intraspecific variation. The results show that the geographical scale of sampling has a critical impact on the global application of DNA barcoding. Scale-effects result from the relative importance of different processes determining the composition of regional species assemblages (dispersal and ecological assembly) and global clades (demography, speciation, and extinction). The incorporation of geographical information, where available, will be required to obtain identification rates at global scales equivalent to those in regional barcoding studies. Our result hence provides an impetus for both smarter barcoding tools and sprouting national barcoding initiatives smaller geographical scales deliver higher accuracy.

  • 88.
    Bergström, Kristofer
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Impact of Using Macroalgae from the Baltic Sea in Biogas Production: A Review with Special Emphasis on Heavy Metals2012Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    A consequence of eutrophication in the Baltic Sea is growth of algae that accumulates in the coastal areas and beaches. Dense algal mats may cause anoxia or hypoxia and greatly reduce the recreational value of the area. Algae also functions as hyper accumulators of heavy metals and their metal levels may become toxic to higher trophic levels. The project Wetlands, Algae and Biogas (WAB) aims at removing algal beach cast for commercial use in biogas production and further use of the fermentation residues as fertilizer. Collection of algae would remove both nutrients and heavy metals from the Baltic Sea but leave us with large amounts of algae containing heavy metals. A concern for the biogas production based on these Baltic algae is the effects from the heavy metals, during fermentation, in the residues and the use of them as fertilizer. A literature review shows that the levels of heavy metals should not inhibit the biogas production but during the fermentation there is a loss of (48%) biological material and the metals are concentrated in the residues. Samples of algae from Trelleborg (SE) show higher concentrations of cadmium (Cd) than algae from Poland (PL). The Swedish residues border or surpass the legislative amount of heavy metals that are allowed to be applied to arable land in Sweden. This is both due to the higher concentrations of heavy metals and the differences between European and Swedish legislation. To use the residues as fertilizer detoxification is required, mainly for Cd in Sweden. There are effective methods, chemicals and ion exchangers (70-80%), for removing heavy metals from organic leachate. But these methods lack testing on a large scale, the costs and the environmental aspect of these methods on tons of algae per year are unknown. Co-fermentation with a suitable substrate would dilute the heavy metal concentration and could reduce possible problems such as hydrogen sulfide accumulation in the biogas. Another possible pathway for dealing with the heavy metal rich residues is as fertilizer for non-food crops such as the biofuel species willow (Salix). Willow is a fast growing tree that is a known accumulator of heavy metals and can be used as a remediation for contaminated soil. Based on the metal concentrations and respective legislation, estimations of 20 000 ha of willow for Trelleborg and 400 ha for Sopot beach (PL) is needed to process harvested algae. 

  • 89.
    Bergström, Kristofer
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Rapid Changes in Salinity and Cyanobacterial Exposure Influence condition of Young of the Year (YOY) Perch (Perca fluviatilis): A Field Study in the Curonian Lagoon(Lithuania)2010Independent thesis Advanced level (degree of Master (One Year)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Two decades ago the recruitment of YOY perch (Perca fluviatilis) started to decline along the Swedish east cost of the Baltic Sea. Factors that influence recruitment are e.g. eutrophication that causes habitat losses and overfishing of cod (Gadus morhua) which causes cascading effects in the food web. Filamentous cyanobacterial blooms are often toxic and has increased in the Baltic Sea and its coastal waters. The aim of this field study was to evaluate the effects of salinity and cyanobacterial exposure on fitness related parameters of young of the year (YOY) perch (Perca Fluviatilis) in a natural environment. Our study was performed in the Curonian Lagoon (Lithuania) in August 2009. The lagoon offers a temporary salinity gradient (wind induced influxes from the Baltic Sea) ranging from 7 psu in the north to 0 psu in the south. Submerged enclosures containing YOY perch were set up at three different locations along the salinity gradient in the Lagoon (referred to as North, Middle, South). The duration of the experiment was 21 or 27 days, depending on treatment. Measurements of perch condition were specific growth rate, somatic condition index (SCI) and whole fish lipid and protein content. Average chl a values for the three stations during the experimental time were: north 180 ± 70 µg/l chl a, middle 133 ± 36 µg/l chl a and south 180 ± 52 µg/l chl a. The North and the Middle stations experienced two different salinity influxes reaching a maximum salinity of 6.5 psu at the northern station. The duration of each saline influx was approximately 4-6 days. The saline water did not reach the Southern station at any time. Results show that perch from the southern station were in best condition in terms of specific growth rate and contents of total lipids. Compared to the South the perch condition declined to the Middle station and was lowest at the Northern station which experienced the highest degree of fluctuation in terms of salinity and cyanobacterial exposure. Examination of the abundance of the main food resource at the different stations revealed no statistical differences, which suggest that availability of food was not a factor in explaining the differences in growth.  The results possibly indicate that a changing environment with the potential synergistic negative effects of salinity and cyanobacteria has a higher negative impact on YOY perch condition compared to constantly high concentrations of cyanobacteria.

  • 90.
    Bergström, Maria
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Åström, Eva
    Påhlsson, Peter
    Ohlson, Sten
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Elucidating the selectivity of recombinant forms of Aleuria aurantia lectin using weak affinity chromatography2012In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 885-886, p. 66-72Article in journal (Refereed)
    Abstract [en]

    Aberrant glycosylation is connected to several pathological conditions and lectins are useful tools to characterize glycosylated biomarkers. The Aleuria aurantia lectin (AAL) is of special interest since it interacts with all types of fucosylated saccharides. AAL has been expressed in E.coli as a fully functional recombinant protein. Engineered variants of AAL have been developed with the aim of creating monovalent lectins with more homogenous binding characteristics. Four different forms of AAL were studied in the present work: native AAL purified from Aleuria aurantia mushrooms, recombinant AAL dimer, recombinant AAL monomer and recombinant AAL site 2 (S2-AAL). The affinities of these AAL forms towards a number of saccharides were determined with weak affinity chromatography (WAC). Disaccharides with fucose linked α1-3 to GlcNAc interacted with higher affinity compared to fucose linked α1-6 or α1-4 and the obtained dissociation constants (Kd) were in the range of 10 μM for all AAL forms. Tetra- and pentasaccharides with fucose in α1-2, α1-3 or α1-4 had Kd values ranging from 0.1–7 mM while a large α1-6 fucosylated oligosaccharide had a Kd of about 20 μM. The recombinant multivalent AAL forms and native AAL exhibited similar affinities towards all saccharides, but S2-AAL had a lower affinity especially regarding a sialic acid containing fucosylated saccharide. It was demonstrated that WAC is a valuable technique in determining the detailed binding profile of the lectins. Specific advantages with WAC include a low consumption of non-labeled saccharides, possibility to analyze mixtures and a simple procedure using standard HPLC equipment.

  • 91. Berndtsson, R
    et al.
    Hogland, William
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Larsson, M
    Dator-modellering för bestämning av bräddning: Ett nytt hjälpmedel vid upprättandet av saneringsplaner1985In: Vann, ISSN 0042-2592, Vol. 20, no 2, p. 107-112Article in journal (Refereed)
  • 92. Berndtsson, R
    et al.
    Hogland, William
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Larsson, M
    Mathematical modelling of combined sewer overflow quality, urban drainage modelling1986In: Proceedings of the International Symposium on Comparison of Urban Drainage Models with Real Catchment Data, UDM'86, Dubrovnik, Yugoslavia: Pergamon Press , 1986, p. 305-315Chapter in book (Other academic)
  • 93. Berndtsson, R
    et al.
    Hogland, William
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Larsson, M
    Niemczynowicz, J
    Aspects of computer modelling techniques for a semi-arid small catchment in Tunisia, Urban Drainage Modeling1986In: Proceedings of the International Symposium on Comparison of Urban Drainage Models with Real Catchment Data, UDM'86, Dubrovnik, Yugoslavia: Pergamon Press , 1986, p. 285-291Chapter in book (Other academic)
  • 94.
    Berntsson, Joel
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Prevalensen av katarakt i Bolivia2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syfte: Syftet var att undersöka prevalensen av katarakt i Bolivia under en resa med den svenska hjälporganisationen Vision For All.

    Metod: Undersökningarna utfördes med hjälp av handhållet oftalmoskop av modellen Heine Beta 200S. Undersökningen genomfördes i genomfallande ljus på ca 30 cm avstånd mellan patient och undersökare. De eventuella opaciteterna i linsen graderades efter hur omfattande de var där grad 0 var inga opaciteter och grad 4 var helt opak lins och grad 5 visade att linsen inte kunde undersökas på grund av oklar hornhinna eller dylikt. Patienterna sökte själva upp undersökningsplatserna som var belägna i städerna Santa Cruz de la Sierra och San José de Chiquitos. Eftersom det fanns begränsat med plats i bagageutrymmet på resan till Bolivia, valdes en väldigt enkel metod som inte krävde avancerad utrustning.

    Resultat: Totalt medverkade 453 personer i studien, det vill säga 906 ögon. Medelåldern var 50,19 ±15,51 år. 62, 91% av personerna som undersöktes var kvinnor. Det totala antalet ögon som hade någon grad av katarakt var 241 stycken, vilket motsvarar 26,60%. Vid jämförelse av de olika städerna, Santa Cruz de la Sierra och San José de Chiquitos, visade det att framförallt prevalensen av katarakt grad 3 var högre i San José de Chiquitos.

    Slutsats: I båda städerna, Santa Cruz de la Sierra och San José de Chiquitos finns stora problem med katarakt. Förutom att försöka öka tillgängligheten på operationer, borde det läggas resurser på att tillgängliggöra information gällande vikten av att skydda sina ögon vid stark UV- strålning.

  • 95.
    Betzholtz, Per-Eric
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Berger, Tobias
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Petersson, J.
    County Administrative Board of Kalmar.
    Stedt, Johan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    What do population viability analyses tell about the future for Baltic Dunlin Calidris alpina schinzii and Montagu’s Harrier Circus pygargus on Öland?2010In: Ornis Svecica, ISSN 1102-6812, Vol. 20, p. 93-102Article in journal (Refereed)
    Abstract [en]

    Population viability analysis (PVA) has become an important tool in conservation biology. Even though detailed outcomes of PVA:s are constrained by data quality, it is a useful approach when the objective is exploratory, aiming to identify important parameters for viability or to guide future field work on endangered species. In this study we perform PVA:s based on scarce data to explore viability of two endangered bird species, Baltic Dunlin and Montagu’s Harrier, on Öland. Our simulation results underline that both species are under severe threats, with a median time to extinction of 24 years in Baltic Dunlin and 63 years in Montagu’s Harrier. Sensitivity analyses show that population growth rate is the most important factor for the model outcome in both species. Since there are no apparent threats for adult birds on Öland, this suggests that conservation measures should focus on improving conditions for successful breeding on the island. In additional simulations we explore some threats in more detail. In the case of Baltic Dunlin nest predation of eggs and chicks increase the extinction risk. In Montagu’s Harrier viability increases if breeding attempts within agricultural areas are detected and safeguarded. In order to enhance the PVA model, and build a stage-structured model, we suggest that detailed data on fecundity and survival should be collected.

  • 96.
    Betzholtz, Per-Eric
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Franzén, Markus
    Department of Community Ecology, UFZ Centre for Environmental Research, Halle, Germany.
    Mobility is related to species traits in noctuid moths2011In: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 36, p. 369-376Article in journal (Refereed)
    Abstract [en]

    Abstract. 1. Mobility is important for the understanding of how species survive infragmented landscapes and cope with increasing rates of habitat and climate change.However, mobility is a difficult trait to explore and is poorly known in most taxa.Species traits have been studied in relation to range shifts, extinction risks, andresponses to habitat area and isolation, and have also been suggested as good estimatorsof mobility. Here we explore the relation between mobility and species traits in noctuidmoths.2. We sampled noctuid moths by an automatic light-trap on an island far out in theBaltic Sea. We compared traits of the non-resident species on the island with traits ofa species pool of assumed potential migrants from the Swedish mainland.3. Mobility was significantly related to adult activity period, length of flightperiod, and the interaction between host-plant specificity and distribution area. Widelydistributed host-plant generalists were more mobile than host-plant specialists withmore restricted distribution, and species with an adult activity period in August toSeptember moved to the island to a higher extent than species with an adult activityperiod in May to July. Our results remained qualitatively robust in additional analyses,after controlling for phylogeny and including all species recorded on the island, exceptfor the trait ‘length of flight period’.4. Our results highlight the importance of the relation between mobility and speciestraits. Noctuid moths with certain traits move over longer distances than earlier known.This finding is important to include when predicting range dynamics in fragmentedand changing landscapes, and when conservation measures of species are devised.

  • 97.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    A Note on the Advances in Adsorption Technology for Water Treatment: Progress and Challenges2012In: Application of Adsorbents for Water Pollution Control / [ed] Amit Bhatnagar, Bentham eBooks, 2012, p. 523-528Chapter in book (Refereed)
  • 98.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Application of Adsorbents for Water Pollution Control2012Collection (editor) (Refereed)
  • 99.
    Bhatnagar, Amit
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Boaventura, R.A.R.
    Vilar, V.J.P.
    Botelho, C.M.S.
    Biosorption of nickel on chemically modified algae2012Conference paper (Other academic)
  • 100.
    Bhatnagar, Amit
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Vilar, V.J.P.
    Botelho, C.M.
    Boaventura, R.A.
    Optimization of nickel biosorption on surface modified algae, COBEQ2012Conference paper (Refereed)
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