| 1. |
- Abbott, J. K., et al.
(författare)
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Patterns of differentiation in a colour polymorphism and in neutral markers reveal rapid genetic changes in natural damselfly populations
- 2008
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Ingår i: Molecular Ecology. - : Wiley-Blackwell. - 0962-1083 .- 1365-294X. ; 17:6, s. 1597-1604
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Tidskriftsartikel (refereegranskat)abstract
- The existence and mode of selection operating on heritable adaptive traits can be inferred by comparing population differentiation in neutral genetic variation between populations (often using F-ST values) with the corresponding estimates for adaptive traits. Such comparisons indicate if selection acts in a diversifying way between populations, in which case differentiation in selected traits is expected to exceed differentiation in neutral markers [F-ST (selected) > F-ST (neutralfl, or if negative frequency-dependent selection maintains genetic polymorphisms and pulls populations towards a common stable equilibrium [FST (selected) < F-ST (neutral)]. Here, we compared F-ST values for putatively neutral data (obtained using amplified fragment length polymorphism) with estimates of differentiation in morph frequencies in the colour-polymorphic damselfly Ischnura elegans. We found that in the first year (2000), population differentiation in morph frequencies was significantly greater than differentiation in neutral loci, while in 2002 (only 2 years and 2 generations later), population differentiation in morph frequencies had decreased to a level significantly lower than differentiation in neutral loci. Genetic drift as an explanation for population differentiation in morph frequencies could thus be rejected in both years. These results indicate that the type and/or strength of selection on morph frequencies in this system can change substantially between years. We suggest that an approach to a common equilibrium morph frequency across all populations, driven by negative frequency-dependent selection, is the cause of these temporal changes. We conclude that inferences about selection obtained by comparing F-ST values from neutral and adaptive genetic variation are most useful when spatial and temporal data are available from several populations and time points and when such information is combined with other ecological sources of data.
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| 2. |
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| 3. |
- Bergström, Staffan, et al.
(författare)
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Development and application of an analytical protocol for evaluation of treatment processes for landfill leachates : I. Development of an analytical protocol for handling organic compounds in complex leachate samples
- 2007
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Ingår i: International Journal of Environmental Analytical Chemistry. - 0306-7319 .- 1029-0397. - 0306-7319 ; 87:1, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- A strategy is presented for evaluation of treatment procedures for landfill leachate with emphasis on organic pollutants. An analytical scheme, the LAQUA protocol, was developed as a guide for the analytical work. The protocol includes organic as well as metals,. inorganic ions, water-quality parameters, and toxicity. The proposed strategy considers the behaviour of both polar and non-polar organic substances at trace levels. For polar substances, phenols were chosen as markers and determined with an automated supported liquid membrane extraction device, coupled on-line to HPLC with a diode-array detector. For non-polar substances, PCBs and 10 unidentified compounds were chosen as markers and analysed by solid-phase extraction combined with supercritical fluid extraction with GC analysis. The chosen measurement strategy, based on the use of marker substances, difference measurements, and versatile data-handling procedures, provided essential information about complex systems at relatively low cost.
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| 4. |
- Bergström, Staffan, et al.
(författare)
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Development and application of an analytical protocol for evaluation of treatment processes for landfill leachates. I. Development of an analytical protocol for handling organic compounds in complex leachate samples
- 2007
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Ingår i: International Journal of Environmental Analytical Chemistry. - : Informa UK Limited. - 1029-0397 .- 0306-7319. ; 87:1, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- A strategy is presented for evaluation of treatment procedures for landfill leachate with emphasis on organic pollutants. An analytical scheme, the LAQUA protocol, was developed as a guide for the analytical work. The protocol includes organic as well as metals,. inorganic ions, water-quality parameters, and toxicity. The proposed strategy considers the behaviour of both polar and non-polar organic substances at trace levels. For polar substances, phenols were chosen as markers and determined with an automated supported liquid membrane extraction device, coupled on-line to HPLC with a diode-array detector. For non-polar substances, PCBs and 10 unidentified compounds were chosen as markers and analysed by solid-phase extraction combined with supercritical fluid extraction with GC analysis. The chosen measurement strategy, based on the use of marker substances, difference measurements, and versatile data-handling procedures, provided essential information about complex systems at relatively low cost.
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| 5. |
- Borg, Christina, 1970-
(författare)
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Structural Growth in Mountain Birch, Betula pubescens ssp. czerepanovii
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, I have studied long shoot performance in the monoecious, deciduous tree Betula pubescens ssp. czerepanovii. In field studies and a common garden experiment, I have a) studied how environmental variations affect the performance of long shoots in mountain birch, and b) described the relationship between long shoot performance and characteristics of the parent long shoot.I have shown that difference in long shoot performance to some extent can be explained by environmental variables such as temperature, precipitation and global radiation the current and previous summer, annual soil and air temperatures, and the length of growing season. For example, a low summer temperature the previous summer had a negative effect on a majority of long shoot characteristics. Variation in shoot characteristics was of the same magnitude along the regional east-western gradient as along the local altitudinal gradient. Variation among individual trees was of the same magnitude as variation among years. Further, long shoot performance was affected by the parent shoot characteristics and reflects that primordia of different organs are formed in the previous summer. On several occasions, freezing damage to mountain birch has been observed on Mt Njulla in northernmost Sweden. Following such damage, fewer but larger leaves emerge. Damages were compensated for with increased number of buds on long shoots produced the same year and one year after damage. Moreover, there were more new long shoots born on short shoots among damaged trees. Dormant buds and short shoots fulfil important functions in a fluctuating environment and as an adaptation to recurring damages of different origin and severity.Differences in the performance among mountain birch saplings grown in a common-garden at Abisko could to a large degree be explained by their origin. Further, saplings from Sweden and from Iceland responded differently to defoliation, and fertilization did not alter the responses to defoliation.
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| 6. |
- Christensen, Anna, et al.
(författare)
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Functional characterization of Arabidopsis calreticulin1a : a key alleviator of endoplasmic reticulum stress
- 2008
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Ingår i: Plant and Cell Physiology. - : Oxford University Press. - 0032-0781 .- 1471-9053. ; 49:6, s. 912-924
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Tidskriftsartikel (refereegranskat)abstract
- The chaperone calreticulin plays important roles in a variety of processes in the endoplasmic reticulum (ER) of animal cells, such as Ca2+ signaling and protein folding. Although the functions of calreticulin are well characterized in animals, only indirect evidence is available for plants. To increase our understanding of plant calreticulins we introduced one of the Arabidopsis isoforms, AtCRT1a, into calreticulin-deficient (crt–/–) mouse embryonic fibroblasts. As a result of calreticulin deficiency, the mouse crt–/– fibroblasts have decreased levels of Ca2+ in the ER and impaired protein folding abilities. Expression of the AtCRT1a in mouse crt–/– fibroblasts rescued these phenotypes, i.e. AtCRT1a restored the Ca2+-holding capacity and chaperone functions in the ER of the mouse crt–/– fibroblasts, demonstrating that the animal sorting machinery was also functional for a plant protein, and that basic calreticulin functions are conserved across the Kingdoms. Expression analyses using a β-glucuronidase (GUS)–AtCRT1a promoter construct revealed high expression of CRT1a in root tips, floral tissues and in association with vascular bundles. To assess the impact of AtCRT1a in planta, we generated Atcrt1a mutant plants. The Atcrt1a mutants exhibited increased sensitivity to the drug tunicamycin, an inducer of the unfolded protein response. We therefore conclude that AtCRT1a is an alleviator of the tunicamycin-induced unfolded protein response, and propose that the use of the mouse crt–/– fibroblasts as a calreticulin expression system may prove useful to assess functionalities of calreticulins from different species.
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| 7. |
- Gromov, Andrei, 1959, et al.
(författare)
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Covalent Amino functionalisation of single walled carbon nanotubes
- 2005
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Ingår i: J. Materials Chem. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 15, s. 3334-3339
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Tidskriftsartikel (refereegranskat)abstract
- Chemical transformation of single-wall carbon nanotubes (SWNT), edge-terminated with carboxylic groups, to SWNT species with amino groups directly attached to the tube open ends has been performed. Different synthetic approaches have been investigated. The reaction products were characterised by FTIR, Raman spectroscopy, XPS and SEM.
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| 8. |
- Hedblad, Bo, et al.
(författare)
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High blood pressure despite treatment: Results from a cross-sectional primary healthcare-based study in southern Sweden.
- 2006
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Ingår i: Scandinavian Journal of Primary Health Care. - : Informa UK Limited. - 0281-3432 .- 1502-7724. ; 24:4, s. 224-230
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To study degree of blood pressure (BP) control in primary healthcare (PHC) treated hypertensive patients in relation to sex, age, drug treatment, and concomitant diseases. Design. Random sample of patients with hypertension. Setting. Ten PHC centres in the Region of Skane, Sweden. Subjects. All the 30- to 95-year-old patients with hypertension who during the period 12 September to 24 September 2004 attended their PHC (146 men and 229 women). Main outcome measures. Achievement of BP control (< 140/90 mmHg) according to European guidelines. Results. Some 90% had been treated > 12 months, 40% had mono-therapy, 15% >= 3 drugs. Use of diuretics was more common in women while use of ACE inhibitors and calcium channel blockers was common in men. Inadequate BP control was related to age; only 22% had BPB < 140/90 mmHg, 38% had a BP >= 160/100 mmHg. BP decline was inversely related to BP measured 12 months or more prior to the present follow-up (r = -0.64, p < 0.001, for systolic and r = -0.67, p < 0.001, for diastolic BP). The systolic or diastolic BP had in every fifth patient during treatment increased by >= 10 mmHg. No association was found between average BP decline and prescribed number of drugs. Conclusion. A minority of the patients had BP below the level (< 140/90 mmHg) recommended by European guidelines. This study illustrates the need for continued follow-up of defined groups of patients in order to improve quality of care.
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