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- Martin, Francis, et al.
(author)
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The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis
- 2008
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 452:7183, s. 7-88
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Journal article (peer-reviewed)abstract
- Mycorrhizal symbioses -- the union of roots and soil fungi -- are universal in terrestrial ecosystems and may have been fundamental to land colonization by plants1,2. Boreal, temperate, and montane forests all depend upon ectomycorrhizae1. Identification of the primary factors that regulate symbiotic development and metabolic activity will therefore open the door to understanding the role of 2 ectomycorrhizae in plant development and physiology, allowing the full ecological significance of this symbiosis to be explored. Here, we report the genome sequence of the ectomycorrhizal basidiomycete Laccaria bicolor (Fig. 1) and highlight gene sets involved in rhizosphere colonization and symbiosis. This 65-million-base genome assembly contains ~ 20,000 predicted protein-encoding genes and a very large number of transposons and repeated sequences. We detected unexpected genomic features most notably a battery of effector-type small secreted proteins (SSP) with unknown function, several of which are only expressed in symbiotic tissues. The most highly expressed SSP accumulates in the proliferating hyphae colonizing the host root. The ectomycorrhizae-specific proteins likely play a decisive role in the establishment of the symbiosis. The unexpected observation that the genome of L. bicolor lacks carbohydrate-active enzymes involved in degradation of plant cell walls, but maintains the ability to degrade non-plant cell walls, reveals the dual saprotrophic and biotrophic lifestyle of the mycorrhizal fungus which enables it to grow within both soil and living plant roots. The predicted gene inventory of the L. bicolor genome, therefore, points to previously unknown mechanisms of symbiosis operating in biotrophic mycorrhizal fungi. The availability of this genome provides an unparalleled opportunity to develop a deeper understanding of the processes by which symbionts interact with plants within their ecosystem in order to perform vital functions in the carbon and nitrogen cycles that are fundamental to sustainable plant productivity.
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2. |
- Dressel, Martina, et al.
(author)
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Total synthesis of (+)-alexine by utilizing a highly stereoselective 3+2 annulation reaction of an N-tosyl-alpha-amino aldehyde and a 1,3-bis(silyl)propene
- 2008
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In: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 14:10, s. 3072-3077
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Journal article (peer-reviewed)abstract
- A novel route towards the polyhydroxylated pyrrolizidine alkaloid (+)-alexine has been developed. A key step in this synthesis is a highly stereoselective [3+2] annulation reaction of N-Ts-alpha-amino aldehyde 7a (Ts=tosyl) and 1,3-bis(silyl)propene 8a for the construction of the polyhydroxylated pyrrolidine subunit of the target molecule. Previous synthetic strategies rely on carbohydrates that require several protecting-group manipulations, thereby making the total number of steps relatively high. The [3+2] annulation strategy compares favorably with carbohydrate-based syntheses and constitutes a highly efficient entry to polyhydroxylated alkaloids.
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3. |
- Fava, Cristiano, et al.
(author)
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Association between adducin-1 G460W variant and blood pressure in Swedes is dependent on interaction with body mass index and gender.
- 2007
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In: American Journal of Hypertension. - : Oxford University Press (OUP). - 1941-7225 .- 0895-7061. ; 20:9, s. 981-989
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Journal article (peer-reviewed)abstract
- Background: The W allele of the G460W polymorphism in the adducin-1 gene has been occasionally associated with increased blood pressure (BP). The aim of this study was to test whether the G460W variant is associated with BP levels and BP progression rate and whether G460W associations with BP are affected by sex, body mass index (BMI), or age. Methods: The G460W polymorphism was genotyped in the population-based Malmo Diet and Cancer-cardiovascular arm (MDC-CVA; n = 6103), of whom 53% had also been examined 11 +/- 4.4 years earlier in the Malmo Preventive Project (MPP). Results: Among subjects without antihypertensive treatment (AHT) in the MDC-CVA (n = 5009), there was no difference between carriers (38%) and noncarriers (62%) of the W allele in systolic BP (139.2 +/- 18.2 v 139.2 +/- 18.5 mm Hg; P = .99) or diastolic BP (85.9 +/- 9.1 v 86.1 +/- 9.2 mm Hg; P = .49). In subjects free from AHT in the MPP and MDC (n = 2637) there was no difference between carriers (38%) and noncarriers (62%) in progression of systolic BP (2.0 +/- 2.5 v 2.0 +/- 2.7 mm Hg/year; P = .45) or diastolic BP (0.59 +/- 1.6 v 0.56 +/- 1.5 mm Hg/year; P = .66) from MPP to MDC. At MDC-CVA BP was influenced by interaction between the G460W and BMI (P = .02 for systolic BP and P = .002 for diastolic BP) and by interaction between G460W and sex (P = .03 for systolic BP and P = .02 for diastolic BP), a result further confirmed by stratified analysis showing that female carriers of the W allele belonging to the upper tertile of BMI had increased systolic BP (146.1 +/- 18.6 v 141.2 +/- 18.6 mm Hg; P < .001), diastolic BP (88.7 +/- 8.7 v 86.1 +/- 8.7 mm Hg; P < .001), and prevalence of hypertension (72.5% v 61.8 %; P = .001). Conclusions: Our data suggest that the G460W polymorphism influences BP when BMI and sex are taken into account.
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4. |
- Fava, Cristiano, et al.
(author)
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Chromosome 2q12, the ADRA2B I/D polymorphism and metabolic syndrome.
- 2009
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In: Journal of Hypertension. - 1473-5598. ; 27, s. 1794-1803
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To test whether a previously hypertension-linked 23 cM region on chromosome 2 is linked to the metabolic syndrome (MetS) or its individual components, and whether a common I/D polymorphism of the adrenergic receptor 2b (ADRA2B) gene, mapping in that region, is associated with the same traits. METHODS: We conducted fine mapping of the hypertension-linked region on chromosome 2 spanning between 107 and 130 cM using 11 informative polymorphic markers in 260 healthy white siblings belonging to 118 nuclear families. Variance-component linkage analysis was performed for each MetS component and a composite sum of MetS phenotypes as quantitative trait after adjustment for significant covariates using 'Solar software package'. Successively, the I/D polymorphism of the ADRA2B gene was genotyped in 5283 patients in the Malmö Diet and Cancer-cardiovascular arm, seeking for association with the MetS using standard definitions and separately, with its individual components. RESULTS: For 24-h pulse pressure and waist/hip ratio, LOD [logarithm of the odds (to the base 10)] scores of more than two were found between 107 and 122 cM on chromosome 2. For the composite sum of MetS phenotypes, LOD score of more than 1 was found between 116 and 120 cM. There was no difference between carriers and noncarriers of the D-allele of the ADRA2B gene in MetS prevalence but D-carriers were associated with significantly higher levels of diastolic blood pressure. CONCLUSION: Our results suggest that chromosome 2 could harbor one or more genes implied in blood pressure homeostasis and MetS development. The ADRA2B I/D polymorphism is not consistently associated with MetS and metabolic/anthropometric parameters but with diastolic blood pressure in an urban-based population of middle-aged Swedes.
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5. |
- Fava, Cristiano, et al.
(author)
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Determinants of kidney function in Swedish families: role of heritable factors.
- 2008
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In: Journal of Hypertension. - 1473-5598. ; 26:9, s. 1773-1779
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Journal article (peer-reviewed)abstract
- The aim of this study was to evaluate the determinants of kidney function and the role of heritable factors in a sample of 249 siblings free from known cardiovascular disease and without antihypertensive drugs belonging to 110 families. Four different measures and estimates of kidney function were considered. Blood pressure was recorded during 24 h by ambulatory blood pressure monitoring. Heritability was estimated with and without adjustment for significant covariates.In multivariate analysis, in addition to age, sex, BMI, HDL-cholesterol, 24-h systolic and mean blood pressure, systolic nocturnal blood pressure dipping resulted independently related to serum creatinine, estimated Cockcroft-Gault-creatinine clearance and estimated by the modification of diet in renal disease-glomerular filtration rate. After full adjustment, the heritability values were 51% for the measured creatinine clearance (P < 0.01), 58% for the estimated Cockcroft-Gault-creatinine clearance (P < 0.001), 40% for the estimated by the modification of diet in renal disease-glomerular filtration rate (P < 0.001), but 8% (P = 0.34) for serum creatinine.Our data confirm that kidney function is partially under genetic control and that genetic variants of importance for this trait could be mapped. The association of the circadian rhythm of blood pressure with kidney function in this sample deserves further investigation.
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7. |
- Fava, Cristiano, et al.
(author)
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Subjects heterozygous for genetic loss of function of the thiazide-sensitive cotransporter have reduced blood pressure
- 2008
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In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 17:3, s. 413-418
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Journal article (peer-reviewed)abstract
- Gitelmans syndrome (GS) is an inherited recessive disorder caused by homozygous or compound heterozygous loss of function mutations of the NaCl cotransporter (NCCT) gene encoding the kidney-expressed NCCT, the pharmacological target of thiazide diuretics. An observational study estimated the prevalence of GS to 19/1 000 000, in Sweden, suggesting that similar to 1% of the population carries one mutant NCCT allele. As the phenotype of GS patients, who always carry two mutant alleles, is indistinguishable from that seen in patients treated with high-dose thiazide diuretics, we aimed at investigating whether subjects carrying one mutated NCCT allele have a phenotype resembling that of treatment with low-dose thiazide diuretics. We screened first-degree relatives of 18 of our patients with an established clinical end genetic diagnosis of GS for NCCT loss of function mutations and identified 35 healthy subjects carrying one mutant allele (GS-heterozygotes). Each GS-heterozygote was assigned a healthy control subject matched for age, BMI and sex. GS-heterozygotes had markedly lower blood pressure (systolic 103.3 +/- 16.4 versus 123.2 +/- 19.4 mmHg; diastolic 62.5 +/- 10.5 versus 73.1 +/- 9.4 mmHg; P < 0.001) than controls. There was no significant difference between the groups either in plasma concentration or urinary excretion rate of electrolytes, however, GS-heterozygotes had higher fasting plasma glucose concentration. Similar to patients being treated with low-dose thiazide diuretics, GS-heterozygotes have markedly lower blood pressure and slightly higher fasting plasma glucose compared with control subjects. Our findings suggest that GS-heterozygotes, the prevalence of which can be estimated to 1%, are partially protected from hypertension through partial genetic loss of function of the NCCT. However, as our study had a case-control design, it is important to underline that any potential effects on population blood pressure and risk of future cardiovascular disease need to be examined in prospective and population-based studies.
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8. |
- Fava, Cristiano, et al.
(author)
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The functional variant of the CLC-Kb channel T481S is not associated with blood pressure or hypertension in Swedes.
- 2007
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In: Journal of Hypertension. - 1473-5598. ; 25:1, s. 111-116
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Journal article (peer-reviewed)abstract
- Objective A common threonine481serine polymorphism (T481S) has been shown in vitro to strongly activate the chloride channel Kb (CLC-Kb) expressed in the kidney, and the 481S allele has been associated with human hypertension. The study aim was to evaluate the association of the T481 S polymorphism with blood pressure (BP) levels and the BP progression rate in Swedes. Design and methods The cardiovascular cohort of the Malmo Diet and Cancer (MDC) study is a population surveyed in 1991-1996 (n = 6103, DNA available on n = 6055), 53% of whom had also been examined 11 +/- 4.4 years earlier in the Malmo preventive Project (MPP) Hypertension was defined as having BP above 140/90 mmHg or being on antihypertensive therapy (AHT). Carriers of one or two copies of the 481S allele were compared with T481T homozygotes (noncarriers). Results Among individuals without AHT in the MIX study (n = 4988) there was no difference between carriers (n = 1164, 23%) and noricarriers (n = 3824, 77%) in systolic BP (139.3 +/- 8.3 vs 139.2 +/- 8.3 mmHg, P=0.82) or diastolic BP (86.0 +/- 9.1 vs 86.0 +/- 9.2 mmHg, P = 0.95). In subjects free from AHT at the Ill and Ill studies (n = 2627) there was no difference between carriers (n = 607, 23%) and noricarriers (n = 2020, 77%) in progression of systolic BP (2.1 +/- 2.6 vs 2.0 +/- 2.8 mmHg/year, P = 0.72) or diastolic BP (0.57 +/- 1.4 vs 0.58 +/- 1.6 mmHg/year, P = 0.85) from Ill to Ill Multivariate analysis gave no support of interaction between the CLC-Kb 481S polymorphism, gender, age or body mass index regarding their effect on BP. Conclusion Our data do not support a role of the CLC-Kb T481S polymorphism in BP regulation in Swedes.
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9. |
- Fava, Cristiano, et al.
(author)
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The V433M Variant of the CYP4F2 Is Associated With Ischemic Stroke in Male Swedes Beyond Its Effect on Blood Pressure.
- 2008
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In: Hypertension. - 1524-4563. ; 52, s. 373-380
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Journal article (peer-reviewed)abstract
- Cytochrome (CYP) 4A11 and CYP4F2 are responsible for renal production of 20-hydroxyeicosatetraenoic acid, a vasoconstrictor and natriuretic substance. The CYP4A11 F434S and CYP4F2 V433M polymorphisms reduce 20-hydroxyeicosatetraenoic acid production in vitro. The aim of the present study was to evaluate the effect of these polymorphisms on blood pressure (BP) levels, hypertension prevalence, and risk of incident cardiovascular events in middle-aged Swedes. The polymorphisms were genotyped in the cardiovascular cohort of the Malmö Diet and Cancer Study. The incidence of cardiovascular events (coronary events, n=276; ischemic stroke, n=199) was monitored over 10 years of follow-up. The analysis of BP levels was performed twice: either excluding or including subjects under antihypertensive treatment. In the whole population, CYP4A11 S434S homozygotes had higher systolic BP, both crude and adjusted for the number of antihypertensive drugs, and higher prevalence of hypertension with respect to F434 carriers. Male, but not female, CYP4F2 M433 carriers had significantly higher crude and adjusted systolic and diastolic BPs and a trend toward higher hypertension prevalence (P=0.06) with respect to V433V homozygotes. After adjustment for major cardiovascular risk factors, the hazard ratio for incident ischemic stroke in male CYP4F2 M433 carriers was significantly higher with respect to V433V homozygotes (hazard ratio: 1.69; 95% CI: 1.10 to 2.60) even when baseline BP levels and hypertension prevalence were included in the Cox proportional hazard model. A common CYP4F2 V433M polymorphism might increase the risk of incident ischemic stroke in male subjects only partially through its elevating effect on BP. Additional studies are needed to confirm these data.
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10. |
- Maggio, Martina, et al.
(author)
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Parallel Simulation of Equation-based Object-Oriented Models with Quantized State Systems on a GPU
- 2009
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In: Proceedings 7th Modelica Conference, Como, Italy, Sep. 20-22, 2009. - Linköping : Linköping University Electronic Press. - 9789173935135 ; , s. 251-260
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Conference paper (peer-reviewed)abstract
- This work focuses on the use of parallel hardware to improve the simulation speed of equation-based object-oriented Modelica models. With this intention,a method has been developed that allows for the translation of a restricted class of Modelica models to parallel simulation code, targeted for the Nvidia Tesla architecture and based on the Quantized State Systems(QSS) simulation algorithm. The OpenModelica Compiler (OMC) has been extended with a new back-end module for automatic generation of the simulation code that uses the CUDA extensions to the C language to be executable with a General Purpose Graphic Processing Unit (GPGPU). Preliminary performance measurments of a small example model havebeen done on the Tesla architecture.
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11. |
- Montagnana, Martina, et al.
(author)
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The Pro12Ala polymorphism of the PPARG gene is not associated with the metabolic syndrome in an urban population of middle-aged Swedish individuals.
- 2008
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In: Diabetic Medicine: A journal of the British Diabetic Association. - : Wiley. - 1464-5491. ; 25:8, s. 902-908
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Journal article (peer-reviewed)abstract
- BACKGROUND: To determine if the common Pro12Ala polymorphism (rs1801282) of the peroxisome proliferator-activated receptor (PPARG) gene is associated with the metabolic syndrome (MetS) or with its individual components in middle-aged Swedish individuals. METHODS: MetS was defined according to the National Cholesterol Education Program/Adult Panel III (NCEP/ATP III), the International Diabetes Federation (IDF) and the European Group for the Study of Insulin Resistance (EGIR) criteria in a population-based sample of nearly 5000 subjects participating in the Malmö Diet and Cancer-cardiovascular arm. RESULTS: Of the subjects included in the analysis, 21.8, 29.4 and 20.4% had MetS according to the NCEP/ATP III, IDF and EGIR (only in subjects without diabetes) definitions, respectively. The Pro12Ala was not associated with MetS or with its individual components. These results were similar when patients with diabetes were excluded. Hypertensive and obese ala-carriers had lower fasting glucose and hypertensive ala-carriers also had lower level triglycerides (P < 0.05). CONCLUSIONS: Our data do not support a major role for the Pro12Ala variant of the PPARG gene in MetS and its individual components. The modest difference in triglyceride and glucose levels, restricted to hypertensive and obese subjects in our cohort, suggests that the polymorphism has a minor effect on glucose and lipid metabolism, particularly in individuals at risk for gluco-metabolic disturbances.
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