1. |
- af Sillén, Ulrika, et al.
(author)
-
Self-rated health in relation to age and gender: influence on mortality risk in the Malmö Preventive Project.
- 2005
-
In: Scandinavian Journal of Public Health. - : SAGE Publications. - 1651-1905 .- 1403-4948. ; 33:3, s. 9-183
-
Journal article (peer-reviewed)abstract
- Aims: A study was undertaken to examine whether poor self-rated health (SRH) can independently predict all-cause mortality during 22-year follow-up in middle-aged men and women. Subjects and methods: Data are derived from a population-based study in Malmo¨ , Sweden. This included baseline laboratory testing and a self-administered questionnaire. The question on global SRH was answered by 15,590 men (mean age 46.4 years) and 10,089 women (49.4 years). Social background characteristics (occupation, marital status) were based on data from national censuses. Mortality was retrieved from national registers. Results: At screening 4,261 (27.3%) men and 3,085 (30.6%) women reported poor SRH. Among subjects rating their SRH as low, 1,022 (24.0%) men and 228 (7.4%) women died during follow-up. Corresponding figures for subjects rating their SRH as high were 1801 (15.9%) men and 376 (5.4%) women. An analysis of survival in subjects reporting poor SRH revealed an age-adjusted hazard risk ratio (HR, 95%CI) for men HR 1.5 (1.4–1.7), and for women HR 1.4 (1.2–1.6). The corresponding HR after adjusting for possible social confounders was for men HR 1.3 (1.1–1.4), and women HR 1.1 (0.9–1.4). When additional adjustment was made for biological risk factors the association for men was still significant, HR 1.2 (1.1–1.3). Conclusion: Poor SRH predicts increased long-term mortality in healthy, middle-aged subjects. For men the association is independent of both social background and selected biological variables. The adjustment for biological variables can be questioned as they might represent mediating mechanisms in a possible causal chain of events.
|
|
2. |
- Andersson, Anders, et al.
(author)
-
A transcriptional timetable of autumn senescence
- 2004
-
In: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 5:4, s. R24-
-
Journal article (peer-reviewed)abstract
- Background We have developed genomic tools to allow the genus Populus (aspens and cottonwoods) to be exploited as a full-featured model for investigating fundamental aspects of tree biology. We have undertaken large-scale expressed sequence tag (EST) sequencing programs and created Populus microarrays with significant gene coverage. One of the important aspects of plant biology that cannot be studied in annual plants is the gene activity involved in the induction of autumn leaf senescence. Results On the basis of 36,354 Populus ESTs, obtained from seven cDNA libraries, we have created a DNA microarray consisting of 13,490 clones, spotted in duplicate. Of these clones, 12,376 (92%) were confirmed by resequencing and all sequences were annotated and functionally classified. Here we have used the microarray to study transcript abundance in leaves of a free-growing aspen tree (Populus tremula) in northern Sweden during natural autumn senescence. Of the 13,490 spotted clones, 3,792 represented genes with significant expression in all leaf samples from the seven studied dates. Conclusions We observed a major shift in gene expression, coinciding with massive chlorophyll degradation, that reflected a shift from photosynthetic competence to energy generation by mitochondrial respiration, oxidation of fatty acids and nutrient mobilization. Autumn senescence had much in common with senescence in annual plants; for example many proteases were induced. We also found evidence for increased transcriptional activity before the appearance of visible signs of senescence, presumably preparing the leaf for degradation of its components.
|
|
3. |
- Carlsson, Lena, et al.
(author)
-
Mode of growth determines differential expression of prostasomes in cultures of prostate cancer cell lines and opens for studies of prostasome gene expression
- 2006
-
In: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 111:3, s. 293-301
-
Journal article (peer-reviewed)abstract
- The exocrine secretion of the acinar gland cells in the human prostate consists of, among other components, a serous secretion and prostasomes. The prostasomes are functionally associated with both reproduction and prostate cancer development and are capable to raise autoantibodies at various pathologies. Therefore, we are trying to characterize prostasome antigens by analysing prostasome- producing cell lines of prostate cancers with the cDNA microarray technique. To obtain one state with synthesis of prostasomes and another state without synthesis, we checked whether the prostasome differentiation was influenced by the mode of growing the cells, that is, whether the cells had been growing on a solid support or on a flexible one. We studied the expression of prostasomes in the cell lines PC3, DU145 and LNCaP. We grew the cells with the following methods: Monocellular layers on microbeads, multicellular spheroids, single cells in suspension cultures, and xenotransplants in nude rats. The presence of prostasomes was examined by ELISA, immunocytochemistry or electron microscopy. The results showed that growing the cells on microbeads (solid support) produced a differentiation of prostasomes, while growing the cells in multicellular spheroids (flexible support) did not. Thus it should be possible to apply cDNA microarray analyses for characterizing the genes which are active at the cellular expression of prostasomes and then deduce the prostasome antigens.
|
|
4. |
- Darj, Elisabeth, et al.
(author)
-
Ki-67 Immunostaining of endometrial biopsies with special reference to hormone replacement therapy
- 1995
-
In: Gynecologic and Obstetric Investigation. - 0378-7346 .- 1423-002X. ; 39:2, s. 120-124
-
Journal article (peer-reviewed)abstract
- BACKGROUND: The purpose of this investigation was to evaluate the Ki-67 immunostaining method on formalin-fixed, paraffin-embedded endometrium and to use the method on endometrial biopsies from 30 postmenopausal women treated with 2 mg estradiol and different doses of natural micronized progesterone (50, 100 or 200 mg). METHODS: Two technicians prepared the immunostaining of slides from each of 12 endometrial specimens and 3 different observers estimated the Ki-67 immunostaining. One observer estimated all the slides 3 times on different occasions. The percentage of immunopositive nuclei in glandular epithelium was evaluated. RESULTS: The dominating component of variation for this method was between observers, with a median standard deviation of 20%. A total median variation including all components rendered a standard deviation of 23%. No significant effects of different technicians, preparations, or from the same observer on different occasions were found. In the major part of the biopsies from women on hormone replacement therapy (HRT), only 0-10% of the glandular epithelium was Ki-67 stained. CONCLUSION: Ki-67 immunostaining is an adequate technique to use when evaluating the effects of HRT on the endometrium. The main source of variation is between observers and not the technique of preparing the slides.
|
|
5. |
- Darreh-Shori, Taher, et al.
(author)
-
Functional variability in butyrylcholinesterase activity regulates intrathecal cytokine and astroglial biomarker profiles in patients with Alzheimer's disease
- 2013
-
In: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 34:11, s. 2465-2481
-
Journal article (peer-reviewed)abstract
- Butyrylcholinesterase (BuChE) activity is associated with activated astrocytes in Alzheimer's disease brain. The BuChE-K variant exhibits 30%-60% reduced acetylcholine (ACh) hydrolyzing capacity. Considering the increasing evidence of an immune-regulatory role of ACh, we investigated if genetic heterogeneity in BuChE affects cerebrospinal fluid (CSF) biomarkers of inflammation and cholinoceptive glial function. Alzheimer's disease patients (n = 179) were BCHE-K-genotyped. Proteomic and enzymatic analyses were performed on CSF and/or plasma. BuChE genotype was linked with differential CSF levels of glial fibrillary acidic protein, S100B, interleukin-1 beta, and tumor necrosis factor (TNF)-alpha. BCHE-K noncarriers displayed 100%-150% higher glial fibrillary acidic protein and 64%-110% higher S100B than BCHE-K carriers, who, in contrast, had 40%-80% higher interleukin-1b and 21%-27% higher TNF-alpha compared with noncarriers. A high level of CSF BuChE enzymatic phenotype also significantly correlated with higher CSF levels of astroglial markers and several factors of the innate complement system, but lower levels of proinflammatory cytokines. These individuals also displayed beneficial paraclinical and clinical findings, such as high cerebral glucose utilization, low beta-amyloid load, and less severe progression of clinical symptoms. In vitro analysis on human astrocytes confirmed the involvement of a regulated BuChE status in the astroglial responses to TNF-alpha and ACh. Histochemical analysis in a rat model of nerve injury-induced neuroinflammation, showed focal assembly of astroglial cells in proximity of BuChE-immunolabeled sites. In conclusion, these results suggest that BuChE enzymatic activity plays an important role in regulating intrinsic inflammation and activity of cholinoceptive glial cells and that this might be of clinical relevance. The dissociation between astroglial markers and inflammatory cytokines indicates that a proper activation and maintenance of astroglial function is a beneficial response, rather than a disease-driving mechanism. Further studies are needed to explore the therapeutic potential of manipulating BuChE activity or astroglial functional status. (C) 2013 Elsevier Inc. All rights reserved.
|
|
6. |
- Elfving, Nils, et al.
(author)
-
The Arabidopsis thaliana Med25 mediator subunit integrates environmental cues to control plant development
- 2011
-
In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108:20, s. 8245-8250
-
Journal article (peer-reviewed)abstract
- Development in plants is controlled by abiotic environmental cues such as day length, light quality, temperature, drought, and salinity. These signals are sensed by a variety of systems and transmitted by different signal transduction pathways. Ultimately, these pathways are integrated to control expression of specific target genes, which encode proteins that regulate development and differentiation. The molecular mechanisms for such integration have remained elusive. We here show that a linear 130-amino-acids-long sequence in the Med25 subunit of the Arabidopsis thaliana Mediator is a common target for the drought response element binding protein 2A, zinc finger homeodomain 1, and Myb-like transcription factors which are involved in different stress response pathways. In addition, our results show that Med25 together with drought response element binding protein 2A also function in repression of PhyB-mediated light signaling and thus integrate signals from different regulatory pathways.
|
|
7. |
- Johansson, Karl-Axel, et al.
(author)
-
The quality assurance process for the ARTSCAN head and neck study - a practical interactive approach for QA in 3DCRT and IMRT.
- 2008
-
In: Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. - : Elsevier BV. - 0167-8140 .- 1879-0887. ; 87:2, s. 290-9
-
Journal article (peer-reviewed)abstract
- AIM: This paper describes the quality assurance (QA) work performed in the Swedish multicenter ARTSCAN (Accelerated RadioTherapy of Squamous cell CArcinomas in the head and Neck) trial to guarantee high quality in a multicenter study which involved modern radiotherapy such as 3DCRT or IMRT. MATERIALS AND METHODS: The study was closed in June 2006 with 750 randomised patients. Radiation therapy-related data for every patient were sent by each participating centre to the QA office where all trial data were reviewed, analysed and stored. In case of any deviation from the protocol, an interactive process was started between the QA office and the local responsible clinician and/or physicist to increase the compliance to the protocol for future randomised patients. Meetings and workshops were held on a regular basis for discussions on various trial-related issues and for the QA office to report on updated results. RESULTS AND DISCUSSION: This review covers the 734 patients out of a total of 750 who had entered the study. Deviations early in the study were corrected so that the overall compliance to the protocol was very high. There were only negligible variations in doses and dose distributions to target volumes for each specific site and stage. The quality of the treatments was high. Furthermore, an extensive database of treatment parameters was accumulated for future dose-volume vs. endpoint evaluations. CONCLUSIONS: This comprehensive QA programme increased the probability to draw firm conclusions from our study and may serve as a concept for QA work in future radiotherapy trials where comparatively small effects are searched for in a heterogeneous tumour population.
|
|
8. |
- Kucukoglu, Melis, et al.
(author)
-
WUSCHEL-RELATED HOMEOBOX4 (WOX4)-like genes regulate cambial cell division activity and secondary growth in Populus trees
- 2017
-
In: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 215, s. 642-657
-
Journal article (peer-reviewed)abstract
- Plant secondary growth derives from the meristematic activity of the vascular cambium. In Arabidopsis thaliana, cell divisions in the cambium are regulated by the transcription factor WOX4, a key target of the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (ESR)-RELATED 41 (CLE41) signaling pathway. However, function of the WOX4-like genes in plants that are dependent on a much more prolific secondary growth, such as trees, remains unclear.Here, we investigate the role of WOX4 and CLE41 homologs for stem secondary growth in Populus trees.In Populus, PttWOX4 genes are specifically expressed in the cambial region during vegetative growth, but not after growth cessation and during dormancy, possibly involving a regulation by auxin. In PttWOX4a/b RNAi trees, primary growth was not affected whereas the width of the vascular cambium was severely reduced and secondary growth was greatly diminished.Our data show that in Populus trees, PttWOX4 genes control cell division activity in the vascular cambium, and hence growth in stem girth. This activity involves the positive regulation of PttWOX4a/b through PttCLE41-related genes. Finally, expression profiling suggests that the CLE41 signaling pathway is an evolutionarily conserved program for the regulation of vascular cambium activity between angiosperm and gymnosperm tree species.
|
|
9. |
- Nilsson, Måns, et al.
(author)
-
The missing link : Bringing institutions and politics into energy future studies
- 2011
-
In: Futures. - : Elsevier BV. - 0016-3287 .- 1873-6378. ; 43:10, s. 1117-1128
-
Journal article (peer-reviewed)abstract
- Energy future studies can be a useful tool for learning about how to induce and manage technical, economic and policy change related to energy supply and use. The private sector has successfully deployed them for strategic planning, examining key parameters such as markets, competition and consumer trends. However in public policy, most energy future studies remain disconnected from policy making. One reason is that they often ignore the key political and institutional factors that underpin much of the anticipated, wished-for or otherwise explored energy systems developments. Still, we know that institutions and politics are critical enablers or constraints to technical and policy change. This paper examines how analytical insights into political and institutional dynamics can enhance energy future studies. It develops an approach that combines systems-technical change scenarios with political and institutional analysis. Using the example of a backcasting study dealing with the long term low-carbon transformation of a national energy system, it applies two levels of institutional and political analysis; at the level of international regimes and at the level of sectoral policy, and examines how future systems changes and policy paths are conditioned by institutional change processes. It finds that the systematic application of these variables significantly enhances and renders more useful backcasting studies of energy futures.
|
|
10. |
|
|
11. |
- Aidas, Kestutis, et al.
(author)
-
On the performance of quantum chemical methods to predict solvatochromic effects: The case of acrolein in aqueous solution.
- 2008
-
In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 128:19, s. 1-194503
-
Journal article (peer-reviewed)abstract
- The performance of the Hartree-Fock method and the three density functionals B3LYP, PBE0, and CAM-B3LYP is compared to results based on the coupled cluster singles and doubles model in predictions of the solvatochromic effects on the vertical n-->pi(*) and pi-->pi(*) electronic excitation energies of acrolein. All electronic structure methods employed the same solvent model, which is based on the combined quantum mechanics/molecular mechanics approach together with a dynamical averaging scheme. In addition to the predicted solvatochromic effects, we have also performed spectroscopic UV measurements of acrolein in vapor phase and aqueous solution. The gas-to-aqueous solution shift of the n-->pi(*) excitation energy is well reproduced by using all density functional methods considered. However, the B3LYP and PBE0 functionals completely fail to describe the pi-->pi(*) electronic transition in solution, whereas the recent CAM-B3LYP functional performs well also in this case. The pi-->pi(*) excitation energy of acrolein in water solution is found to be very dependent on intermolecular induction and nonelectrostatic interactions. The computed excitation energies of acrolein in vacuum and solution compare well to experimental data.
|
|
12. |
- Akhter, Shirin, et al.
(author)
-
Cone-setting in spruce is regulated by conserved elements of the age-dependent flowering pathway
- 2022
-
In: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 236:5, s. 1951-1963
-
Journal article (peer-reviewed)abstract
- Reproductive phase change is well characterized in angiosperm model species, but less studied in gymnosperms. We utilize the early cone-setting acrocona mutant to study reproductive phase change in the conifer Picea abies (Norway spruce), a gymnosperm. The acrocona mutant frequently initiates cone-like structures, called transition shoots, in positions where wild-type P. abies always produces vegetative shoots. We collect acrocona and wild-type samples, and RNA-sequence their messenger RNA (mRNA) and microRNA (miRNA) fractions. We establish gene expression patterns and then use allele-specific transcript assembly to identify mutations in acrocona. We genotype a segregating population of inbred acrocona trees. A member of the SQUAMOSA BINDING PROTEIN-LIKE (SPL) gene family, PaSPL1, is active in reproductive meristems, whereas two putative negative regulators of PaSPL1, miRNA156 and the conifer specific miRNA529, are upregulated in vegetative and transition shoot meristems. We identify a mutation in a putative miRNA156/529 binding site of the acrocona PaSPL1 allele and show that the mutation renders the acrocona allele tolerant to these miRNAs. We show co-segregation between the early cone-setting phenotype and trees homozygous for the acrocona mutation. In conclusion, we demonstrate evolutionary conservation of the age-dependent flowering pathway and involvement of this pathway in regulating reproductive phase change in the conifer P. abies.
|
|
13. |
- Akhter, Shirin, et al.
(author)
-
Integrative Analysis of Three RNA Sequencing Methods Identifies Mutually Exclusive Exons of MADS-Box Isoforms During Early Bud Development in Picea abies
- 2018
-
In: Frontiers in Plant Science. - : Frontiers Media S.A.. - 1664-462X. ; 9
-
Journal article (peer-reviewed)abstract
- Recent efforts to sequence the genomes and transcriptomes of several gymnosperm species have revealed an increased complexity in certain gene families in gymnosperms as compared to angiosperms. One example of this is the gymnosperm sister Glade to angiosperm TM3-like MADS-box genes, which at least in the conifer lineage has expanded in number of genes. We have previously identified a member of this subclade, the conifer gene DEFICIENS AGAMOUS LIKE 19 (DAL19), as being specifically upregulated in cone-setting shoots. Here, we show through Sanger sequencing of mRNA-derived cDNA and mapping to assembled conifer genomic sequences that DAL19 produces six mature mRNA splice variants in Picea abies. These splice variants use alternate first and last exons, while their four central exons constitute a core region present in all six transcripts. Thus, they are likely to be transcript isoforms. Quantitative Real-Time PCR revealed that two mutually exclusive first DAL19 exons are differentially expressed across meristems that will form either male or female cones, or vegetative shoots. Furthermore, mRNA in situ hybridization revealed that two mutually exclusive last DAL19 exons were expressed in a cell-specific pattern within bud meristems. Based on these findings in DAL19, we developed a sensitive approach to transcript isoform assembly from short-read sequencing of mRNA. We applied this method to 42 putative MADS-box core regions in P abies, from which we assembled 1084 putative transcripts. We manually curated these transcripts to arrive at 933 assembled transcript isoforms of 38 putative MADS-box genes. 152 of these isoforms, which we assign to 28 putative MADS-box genes, were differentially expressed across eight female, male, and vegetative buds. We further provide evidence of the expression of 16 out of the 38 putative MADS-box genes by mapping PacBio Iso-Seq circular consensus reads derived from pooled sample sequencing to assembled transcripts. In summary, our analyses reveal the use of mutually exclusive exons of MADS-box gene isoforms during early bud development in P. abies, and we find that the large number of identified MADS-box transcripts in P. abies results not only from expansion of the gene family through gene duplication events but also from the generation of numerous splice variants.
|
|
14. |
- Akhter, Shirin, et al.
(author)
-
Transcriptome studies of the early cone-setting acrocona mutant provide evidence for a functional conservation of the age-dependent flowering pathway between angiosperms and gymnosperms.
-
Other publication (other academic/artistic)abstract
- All seed plants go through a juvenile period before they initiate seed- and pollen-bearing organs and reproduce. Reproductive phase-change is well characterized in angiosperm model species, but much less well described in gymnosperms. Here, we utilize the early cone-setting acrocona mutant to study reproductive phase change in the conifer Picea abies; a representative of the gymnosperm lineage. The acrocona mutant frequently initiates cone-like structures, called transition shoots, in positions where wild-type P. abies always produces vegetative shoots. By sequence analysis of mRNA and microRNA transcripts, we demonstrate that orthologous components of the Age-dependent flowering pathway are active at the time of cone initiation. We show that a member of the SQUAMOSA BINDING PROTEIN-LIKE (SPL) gene family, PaSPL7, is active in reproductive meristems, whereas a putative negative regulator of PaSPL7, microRNA156 is upregulated in vegetative meristem. By allele-specific assembly, we also identify a short nucleotide polymorphism (SNP) in the miRNA156 binding of PaSPL7. By genotyping a segregating population of inbred acrocona trees, we show a clear co-segregation between the early cone-setting phenotype and trees homozygous for the SNP. Hence, the data presented demonstrate evolutionary conservation of the age-dependent flowering pathway and involvement of this pathway in regulating cone-setting in the conifer P. abies.
|
|
15. |
|
|
16. |
- Andersson, Jens A, et al.
(author)
-
Intelligent debugger
- 1976
-
In: Elteknik. - 0013-6425.
-
Journal article (peer-reviewed)
|
|
17. |
- André, Domenique, et al.
(author)
-
FLOWERING LOCUS T paralogs control the annual growth cycle in Populus trees
- 2022
-
In: Current Biology. - : Cell Press. - 0960-9822 .- 1879-0445. ; 32:13, s. 2988-2996.e4
-
Journal article (peer-reviewed)abstract
- In temperate and boreal regions, perennials adapt their annual growth cycle to the change of seasons. These adaptations ensure survival in harsh environmental conditions, allowing growth at different latitudes and altitudes, and are therefore tightly regulated. Populus tree species cease growth and form terminal buds in autumn when photoperiod falls below a certain threshold.1 This is followed by establishment of dormancy and cold hardiness over the winter. At the center of the photoperiodic pathway in Populus is the gene FLOWERING LOCUS T2 (FT2), which is expressed during summer and harbors significant SNPs in its locus associated with timing of bud set.1–4 The paralogous gene FT1, on the other hand, is hyper-induced in chilling buds during winter.3,5 Even though its function is so far unknown, it has been suggested to be involved in the regulation of flowering and the release of winter dormancy.3,5 In this study, we employ CRISPR-Cas9-mediated gene editing to individually study the function of the FT-like genes in Populus trees. We show that while FT2 is required for vegetative growth during spring and summer and regulates the entry into dormancy, expression of FT1 is absolutely required for bud flush in spring. Gene expression profiling suggests that this function of FT1 is linked to the release of winter dormancy rather than to the regulation of bud flush per se. These data show how FT duplication and sub-functionalization have allowed Populus trees to regulate two completely different and major developmental control points during the yearly growth cycle.
|
|
18. |
- André, Domenique, et al.
(author)
-
Phytochrome B and PHYTOCHROME INTERACTING FACTOR8 modulate seasonal growth in trees
- 2021
-
In: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 232, s. 2339-2352
-
Journal article (peer-reviewed)abstract
- The seasonally synchronized annual growth cycle that is regulated mainly by photoperiod and temperature cues is a crucial adaptive strategy for perennial plants in boreal and temperate ecosystems.Phytochrome B (phyB), as a light and thermal sensor, has been extensively studied in Arabidopsis. However, the specific mechanisms for how the phytochrome photoreceptors control the phenology in tree species remain poorly understood.We characterized the functions of PHYB genes and their downstream PHYTOCHROME INTERACTING FACTOR (PIF) targets in the regulation of shade avoidance and seasonal growth in hybrid aspen trees. We show that while phyB1 and phyB2, as phyB in other plants, act as suppressors of shoot elongation during vegetative growth, they act as promoters of tree seasonal growth. Furthermore, while the Populus homologs of both PIF4 and PIF8 are involved in the shade avoidance syndrome (SAS), only PIF8 plays a major role as a suppressor of seasonal growth.Our data suggest that the PHYB-PIF8 regulon controls seasonal growth through the regulation of FT and CENL1 expression while a genome-wide transcriptome analysis suggests how, in Populus trees, phyB coordinately regulates SAS responses and seasonal growth cessation.
|
|
19. |
- André, Domenique, et al.
(author)
-
Populus SVL Acts in Leaves to Modulate the Timing of Growth Cessation and Bud Set
- 2022
-
In: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 13
-
Journal article (peer-reviewed)abstract
- SHORT VEGETATIVE PHASE (SVP) is an important regulator of FLOWERING LOCUS T (FT) in the thermosensory pathway of Arabidopsis. It is a negative regulator of flowering and represses FT transcription. In poplar trees, FT2 is central for the photoperiodic control of growth cessation, which also requires the decrease of bioactive gibberellins (GAs). In angiosperm trees, genes similar to SVP, sometimes named DORMANCY-ASSOCIATED MADS-BOX genes, control temperature-mediated bud dormancy. Here we show that SVL, an SVP ortholog in aspen trees, besides its role in controlling dormancy through its expression in buds, is also contributing to the regulation of short day induced growth cessation and bud set through its expression in leaves. SVL is upregulated during short days in leaves and binds to the FT2 promoter to repress its transcription. It furthermore decreases the amount of active GAs, whose downregulation is essential for growth cessation, by repressing the transcription of GA20 oxidase. Finally, the SVL protein is more stable in colder temperatures, thus integrating the temperature signal into the response. We conclude that the molecular function of SVL in the photoperiodic pathway has been conserved between Arabidopsis and poplar trees, albeit the physiological process it controls has changed. SVL is thus both involved in regulating the photoperiod response in leaves, modulating the timing of growth cessation and bud set, and in the subsequent temperature regulation of dormancy in the buds.
|
|
20. |
- Barcala, Maximiliano Estravis, et al.
(author)
-
Whole-genome resequencing facilitates the development of a 50K single nucleotide polymorphism genotyping array for Scots pine (Pinus sylvestris L.) and its transferability to other pine species
- 2024
-
In: The Plant Journal. - : John Wiley & Sons. - 0960-7412 .- 1365-313X. ; 117:3, s. 944-955
-
Journal article (peer-reviewed)abstract
- Scots pine (Pinus sylvestris L.) is one of the most widespread and economically important conifer species in the world. Applications like genomic selection and association studies, which could help accelerate breeding cycles, are challenging in Scots pine because of its large and repetitive genome. For this reason, genotyping tools for conifer species, and in particular for Scots pine, are commonly based on transcribed regions of the genome. In this article, we present the Axiom Psyl50K array, the first single nucleotide polymorphism (SNP) genotyping array for Scots pine based on whole-genome resequencing, that represents both genic and intergenic regions. This array was designed following a two-step procedure: first, 192 trees were sequenced, and a 430K SNP screening array was constructed. Then, 480 samples, including haploid megagametophytes, full-sib family trios, breeding population, and range-wide individuals from across Eurasia were genotyped with the screening array. The best 50K SNPs were selected based on quality, replicability, distribution across the draft genome assembly, balance between genic and intergenic regions, and genotype–environment and genotype–phenotype associations. Of the final 49 877 probes tiled in the array, 20 372 (40.84%) occur inside gene models, while the rest lie in intergenic regions. We also show that the Psyl50K array can yield enough high-confidence SNPs for genetic studies in pine species from North America and Eurasia. This new genotyping tool will be a valuable resource for high-throughput fundamental and applied research of Scots pine and other pine species.
|
|
21. |
- Benlloch, Reyes, et al.
(author)
-
An Antagonistic Pair of FT Homologs Mediates the Control of Flowering Time in Sugar Beet
- 2010
-
In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 330, s. 1397-1400
-
Journal article (peer-reviewed)abstract
- Cultivated beets (Beta vulgaris ssp. vulgaris) are unable to form reproductive shoots during the first year of their life cycle. Flowering only occurs if plants get vernalized, that is, pass through the winter, and are subsequently exposed to an increasing day length (photoperiod) in spring. Here, we show that the regulation of flowering time in beets is controlled by the interplay of two paralogs of the FLOWERING LOCUS T (FT) gene in Arabidopsis that have evolved antagonistic functions. BvFT2 is functionally conserved with FT and essential for flowering. In contrast, BvFT1 represses flowering and its down-regulation is crucial for the vernalization response in beets. These data suggest that the beet has evolved a different strategy relative to Arabidopsis and cereals to regulate vernalization.
|
|
22. |
- Benlloch, Reyes, et al.
(author)
-
Analysis of the Developmental Roles of the Arabidopsis Gibberellin 20-Oxidases Demonstrates That GA20ox1, -2, and -3 Are the Dominant Paralogs
- 2012
-
In: Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 24, s. 941-960
-
Journal article (peer-reviewed)abstract
- Gibberellin (GA) biosynthesis is necessary for normal plant development, with later GA biosynthetic stages being governed by multigene families. Arabidopsis thaliana contains five GA 20-oxidase (GA20ox) genes, and past work has demonstrated the importance of GA20ox1 and -2 for growth and fertility. Here, we show through systematic mutant analysis that GA20ox1, -2, and -3 are the dominant paralogs; their absence results in severe dwarfism and almost complete loss of fertility. In vitro analysis revealed that GA20ox4 has full GA20ox activity, but GA20ox5 catalyzes only the first two reactions of the sequence by which GA(12) is converted to GA(9). GA20ox3 functions almost entirely redundantly with GA20ox1 and -2 at most developmental stages, including the floral transition, while GA20ox4 and -5 have very minor roles. These results are supported by analysis of the gene expression patterns in promoter:beta-glucuronidase reporter lines. We demonstrate that fertility is highly sensitive to GA concentration, that GA20ox1, -2, and -3 have significant effects on floral organ growth and anther development, and that both GA deficiency and overdose impact on fertility. Loss of GA20ox activity causes anther developmental arrest, with the tapetum failing to degrade. Some phenotypic recovery of late flowers in GA-deficient mutants, including ga1-3, indicated the involvement of non-GA pathways in floral development.
|
|
23. |
- Benlloch, Reyes, et al.
(author)
-
Integrating long-day flowering signals : a LEAFY binding site is essential for proper photoperiodic activation of APETALA1
- 2011
-
In: The Plant Journal. - Oxford : Blackwell. - 0960-7412 .- 1365-313X. ; 67:6, s. 1094-1102
-
Journal article (peer-reviewed)abstract
- The transition to flowering in Arabidopsis is characterized by the sharp and localized upregulation of APETALA1 (AP1) transcription in the newly formed floral primordia. Both the flower meristem-identity gene LEAFY (LFY) and the photoperiod pathway involving the FLOWERING LOCUS T (FT) and FD genes contribute to this upregulation. These pathways have been proposed to act independently but their respective contributions and mode of interaction have remained elusive. To address these questions, we studied the AP1 regulatory region. Combining in vitro and in vivo approaches, we identified which of the three putative LFY binding sites present in the AP1 promoter is essential for its activation by LFY. Interestingly, we found that this site is also important for the correct photoperiodic-dependent upregulation of AP1. In contrast, a previously proposed putative FD-binding site appears dispensable and unable to bind FD and we found no evidence for FD binding to other sites in the AP1 promoter, suggesting that the FT/FD-dependent activation of AP1 might be indirect. Altogether, our data give new insight into the interaction between the FT and LFY pathways in the upregulation of AP1 transcription under long-day conditions.
|
|
24. |
- Björ, Ove, 1967-, et al.
(author)
-
A comparison between standard methods and structural nested modelling when bias from a healthy worker survivor effect is suspected : an iron-ore mining cohort study
- 2015
-
In: Occupational and Environmental Medicine. - : BMJ. - 1351-0711 .- 1470-7926. ; 72:7, s. 536-542
-
Journal article (peer-reviewed)abstract
- Objectives Iron-ore miners are exposed to extremely dusty and physically arduous work environments. The demanding activities of mining select healthier workers with longer work histories (ie, the Healthy Worker Survivor Effect (HWSE)), and could have a reversing effect on the exposure-response association. The objective of this study was to evaluate an iron-ore mining cohort to determine whether the effect of respirable dust was confounded by the presence of an HWSE. Methods When an HWSE exists, standard modelling methods, such as Cox regression analysis, produce biased results. We compared results from g-estimation of accelerated failure-time modelling adjusted for HWSE with corresponding unadjusted Cox regression modelling results. Results For all-cause mortality when adjusting for the HWSE, cumulative exposure from respirable dust was associated with a 6% decrease of life expectancy if exposed >= 15 years, compared with never being exposed. Respirable dust continued to be associated with mortality after censoring outcomes known to be associated with dust when adjusting for the HWSE. In contrast, results based on Cox regression analysis did not support that an association was present. Conclusions The adjustment for the HWSE made a difference when estimating the risk of mortality from respirable dust. The results of this study, therefore, support the recommendation that standard methods of analysis should be complemented with structural modelling analysis techniques, such as g-estimation of accelerated failure-time modelling, to adjust for the HWSE.
|
|
25. |
- Björ, Ove, 1967-, et al.
(author)
-
Do physical workload or temperature characteristics in an outdoor workingenvironment explain deviating rates of mortality and incidental cancer? A cohort study based on iron-ore mining.
-
Other publication (other academic/artistic)abstract
- Background A cohort study that examined iron ore mining found negative associations between cumulative working time employed underground and several severe outcomes. In this cohort study, and using the same group of miners, we examined whether heavy physical workload or the temperature characteristics represented by an outdoor working environment could explain these lower rates.Method This study was based on a Swedish iron ore mining cohort consisting of 13000 workers employed between 1923 and 1998. Exposure was defined as cumulative employment time in heavy physical workload or outdoor work. Poisson regression models were used to generate smoothed estimates of standardized morbidity ratios and adjusted rate ratios, both models by cumulative exposure time. SMRs for different cohort subgroups were used to compare the occurrence of cerebrovascular disease mortality to the reference population.Results The adjusted rate ratio between employment classified as outdoor work ≥25 years and short term outdoor work was 1.62 (95% CI 1.07–2.42). The subgroup underground work ≥15 years deviated most in occurrence of cerebrovascular disease mortality compared with the reference population: SMR (0.70 (95% CI 0.56–0.85)). No elevated rates were associated with cumulative employment time representing heavy physical workloads.Conclusion Employment in temperature shifting outdoor environments was associated with elevated rates of cerebrovascular disease mortality. In contrast, work in tempered underground employment was associated with a protecting effect. Based on selected groups of mortalities, physically heavy workloads did not protect for mortality later in life.
|
|