| 41. |
- Barcala, Maximiliano Estravis, et al.
(författare)
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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
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Ingår i: The Plant Journal. - 0960-7412 .- 1365-313X. ; 117:3, s. 944-955
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Tidskriftsartikel (refereegranskat)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.
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| 42. |
- Berggrund, Malin, et al.
(författare)
-
HPV viral load in self-collected vaginal fluid samples as predictor for presence of cervical intraepithelial neoplasia.
- 2019
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Ingår i: Virology Journal. - : Springer Science and Business Media LLC. - 1743-422X. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: This study was performed to evaluate the use of high-risk HPV (hrHPV) viral load in screening tests for cervical cancer to predict persistent infection and presence of cervical intraepithelial neoplasia grade 2 or worse (CIN2+).METHODS: We followed women between 30 and 60 years of age who performed self-sampling of vaginal fluid and subsequently a hrHPV test. Women who were hrHPV positive in their screening test repeated the hrHPV test 3-6 months later and were included in the present study.RESULTS: Our results show that women with a persistent HPV16 infection had higher HPV viral load in their primary screening test than women with transient infections (p = 5.33e-03). This was also true for sum of viral load for all hrHPV types in the primary screening test (p = 3.88e-07). 48% of women with persistent HPV16 infection and CIN2+ had an increase in HPV16 titer in the follow-up test, as compared to only 20% of women with persistent infection but without CIN2+ lesions. For the sum of all hrHPV types, 41% of women with persistent infection and CIN2+ had an increase in titer as compared to 26% of women without CIN2 + .CONCLUSIONS: The results show that hrHPV viral load in the primary screening HPV test is associated with the presence of CIN2+ and could be used in triaging hrHPV positive women for different follow-up strategies or recall times. Serial testing of hrHPV viral load has the potential to distinguish women with CIN2+ lesions from women with persistent infection but without CIN2+ lesions.
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| 43. |
- Berggrund, Malin, 1989-
(författare)
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Identification and clinical implementation of biomarkers for cervical cancer
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction of organised screening programs and prophylactic vaccination against human papilloma virus (HPV) have successfully reduced the incidence of cervical cancer globally. In Sweden, the incidence has been reduced by about 50 % since the introduction of the national screening programme in the late 1960’s. Despite these efforts, cervical cancer is still a major cause of cancer deaths globally.In order to reduce cervical cancer, the screening program should have a high participation rate and be based on a sensitive and specific screening test. About 20 % of women in Sweden do not participate in the organised screening program, and during the last years we have also seen a rise in cervical cancer cases in Sweden among women who participate in the screening program. Thus, there is a need to develop improved screening strategies that result in a higher participation rate, and are based on tests that more precisely identify women with high risk of developing cervical cancer. This includes searching for novel biological markers (biomarkers) that can be used to more accurately identify women with a high risk of developing cervical cancer.By offering women self-sampling for HPV analysis through direct mailing of sample kits with a chemically treated paper card, the FTA card, we were able to increase the participation rate in the screening program. We also found that the use of repeated self-sampling for women that were HPV positive in the primary screening sample increased the number of women detected with higher risk of cervical cancer (Paper II). Self-sampling was shown to be non-inferior to assisted sampling by midwife (Paper III). Using this sample collection device, we further investigated the association between increased risk of cervical cancer and HPV viral load (Paper V) as well as the vaginal microbiota (Paper VI). We also showed that proteins in the vaginal fluid can be studied using self-sampling and the FTA card (Paper I). Lastly, we identified plasma proteins that are associated with cervical cancer and could represent future biomarkers (Paper IV).This thesis has provided novel aspects on the present screening strategy, explored opportunities to increase the participation rate as well as examined possible future biomarkers for screening of cervical cancer.
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| 44. |
- Berggrund, Malin, et al.
(författare)
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Identification of candidate plasma protein biomarkers for cervical cancer using the multiplex proximity extension assay
- 2019
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 18:4, s. 735-743
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Tidskriftsartikel (refereegranskat)abstract
- Human papillomavirus (HPV) is recommended as the primary test in cervical cancer screening, with co-testing by cytology for HPV-positive women to identify cervical lesions. Cytology has low sensitivity and there is a need to identify biomarkers that could identify dysplasia that are likely to progress to cancer. We searched for plasma proteins that could identify women with cervical cancer using the multiplex proximity extension assay (PEA). The abundance of 100 proteins were measured in plasma collected at the time of diagnosis of patients with invasive cervical cancer and in population controls using the Olink Multiplex panels CVD II, INF I, and ONC II. Eighty proteins showed increased levels in cases compared to controls. We identified a signature of 11 proteins (PTX3, ITGB1BP2, AXIN1, STAMPB, SRC, SIRT2, 4E-BP1, PAPPA, HB-EGF, NEMO and IL27) that distinguished cases and controls with a sensitivity of 0.96 at a specificity of 1.0. This signature was evaluated in a prospective replication cohort with samples collected before, at or after diagnosis and achieved a sensitivity of 0.78 and a specificity 0.56 separating samples collected at the time of diagnosis of invasive cancer from samples collected prior to diagnosis. No difference in abundance was seen between samples collected prior to diagnosis or after treatment as compared to population controls, indicating that this protein signature is mainly informative close to time of diagnosis. Further studies are needed to determine the optimal window in time prior to diagnosis for these biomarker candidates.
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| 45. |
- Berggrund, Malin, et al.
(författare)
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Protein Detection Using the Multiplexed Proximity Extension Assay (PEA) from Plasma and Vaginal Fluid Applied to the Indicating FTA Elute Micro Card™
- 2016
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Ingår i: Journal of Circulating Biomarkers. - : SAGE Publications. - 1849-4544. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- The indicating FTA elute micro card? has been developed to collect and stabilize the nucleic acid in biological samples and is widely used in human and veterinary medicine and other disciplines. This card is not recommended for protein analyses, since surface treatment may denature proteins. We studied the ability to analyse proteins in human plasma and vaginal fluid as applied to the indicating FTA elute micro card? using the sensitive proximity extension assay (PEA). Among 92 proteins in the Proseek Multiplex Oncology Iv2 panel, 87 were above the limit of detection (LOD) in liquid plasma and 56 among 92 above LOD in plasma applied to FTA cards. Washing and protein elution protocols were compared to identify an optimal method. Liquid-based cytology samples showed a lower number of proteins above LOD than FTA cards with vaginal fluid samples applied. Our results demonstrate that samples applied to the indicating FTA elute micro card? are amendable to protein analyses, given that a sensitive protein detection assay is used. The results imply that biological samples applied to FTA cards can be used for DNA, RNA and protein detection.
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| 46. |
- Berggrund, Malin, et al.
(författare)
-
Temporal changes in the vaginal microbiota in self-samples and its association with persistent HPV16 infection and CIN2
- 2020
-
Ingår i: Virology Journal. - : Springer Science and Business Media LLC. - 1743-422X. ; 17
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe vaginal microbiota has been reported to be associated with HPV infection and cervical cancer. This study was performed to compare the vaginal microbiota at two timepoints in women performing self-sampling and had a persistent or transient HPV16 infection. The women were tested for 12 high-risk HPV (hrHPV) types but only women with single type (HPV16) were included to reduce confounding variables.MethodsIn total 96 women were included in this study. Of these, 26 were single positive for HPV16 in the baseline test and HPV negative in the follow-up test and 38 were single positive for HPV16 in both tests and diagnosed with CIN2+ in histology. In addition, 32 women that were negative for all 12 HPV tested were included. The samples of vaginal fluid were analyzed with the Ion 16S™ Metagenomics Kit and Ion 16S™ metagenomics module within the Ion Reporter™ software.ResultsK-means clustering resulted in two Lactobacillus-dominated groups, one with Lactobacillus sp. and the other specifically with Lactobacillus iners. The two remaining clusters were dominated by a mixed non-Lactobacillus microbiota. HPV negative women had lower prevalence (28%) of the non-Lactobacill dominant cluster in the baseline test, as compared to women with HPV16 infection (42%) (p value = 0.0173). Transition between clusters were more frequent in women with persistent HPV16 infection (34%) as compared in women who cleared the HPV16 infection (19%) (p value = 0.036).ConclusionsThe vaginal microbiota showed a higher rate of transitioning between bacterial profiles in women with persistent HPV16 infection as compared to women with transient infection. This indicate an instability in the microenvironment in women with persistent HPV infection and development of CIN2+.
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| 47. |
- Bergström, Tomas, et al.
(författare)
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Phylogenetic history of hominoid DRB loci and alleles inferred from intron sequences.
- 1999
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Ingår i: Immunol Rev. - 0105-2896. ; 167, s. 351-65
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Tidskriftsartikel (refereegranskat)abstract
- The evolutionary relationships among the MHC class II DRB4, DRB5 and DRB6 loci as well as the allelic lineages and alleles of the DRB1 locus were studied based on intron 1 and intron 2 sequences from humans, chimpanzee (Pan troglodytes), bonobo (Pan paniscus) and gorilla (Gorilla gorilla). The phylogenetic trees for these sequences indicate that most of the DRB1 allelic lineages predate the separation of the hominoid species studied, consistent with previous analysis of the coding sequences of these lineages. However, the intron sequence variation among alleles within DRB1 allelic lineages is very limited, consistent with the notion that the majority of the contemporary alleles have been generated within the last 250,000 years. The clustering of the DRB1 allelic lineages *08 and *12 with *03 supports a common ancestry for the DR8 and DR52 haplotypes. Similarly, the clustering of DRB1 allelic lineages *15 and *01 with the DRB3 locus is consistent with a common ancestry for the DR1 and DR51 haplotypes. Two cases of recombination around the second exon were observed: 1) the HLA-DRB6 locus appears to have been generated through a recombination between a DRB5 allele and an ancestral DRB6 allele, and 2) the gorilla sequence Gogo-DRB1 *03 appears to have been generated through a recombination between the DRB3 locus and an allele from the DRB1 *03 allelic lineage. The nucleotide substitution rate of DRB introns was estimated to 0.85-1.63 x 10(-9) per site per year, based on comparisons between the most closely related sequences from different hominoid species. This estimate is similar to the substitution rate for other intronic regions of the primate genome.
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| 48. |
- Bergström, Tomas, et al.
(författare)
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Recent origin of HLA-DRB1 alleles and implications for human evolution.
- 1998
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Ingår i: Nat Genet. - 1061-4036. ; 18:3, s. 237-42
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Tidskriftsartikel (refereegranskat)abstract
- The HLA class I and class II loci are the most highly polymorphic coding regions in the human genome. Based on the similarity of the coding sequences of alleles between species, it has been claimed that the HLA polymorphism is ancient and predates the separation of human (Homo) and chimpanzee (Pan), 4-7.4 Myr ago. Analysis of intron sequences, however, provides support for a more recent origin and for rapid generation of alleles at the HLA class II DRB1 locus. The human DRB1 alleles can be divided into groups (allelic lineages); most of these lineages have diverged from each other before the separation of Homo and Pan. Alleles within such a lineage, however, appear to be, on average, 250,000 years old, implying that the vast majority (greater than 90%) of the more than 135 contemporary human DRB1 alleles have been generated after the separation of Homo and Pan. The coalescence time of alleles within allelic lineages indicates that the effective population size (Ne) for early hominids (over the last 1 Myr) was approximately 10(4) individuals, similar to estimates based on other nuclear loci and mitochondrial DNA. With a single exception, the genetic mechanisms (gene conversion and point mutation) that have diversified the exon-2 sequences do not appear to extend into the adjacent intron sequences. The part of exon 2 encoding the beta-sheet evolves in concert with the surrounding introns, while the alpha-helix appears to have been subjected to gene conversion-like events, suggesting that such exchange events are highly localised and occur over extremely short sequence tracts.
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| 49. |
- Bergström, Tomas, et al.
(författare)
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Tracing the origin of HLA-DRB1 alleles by microsatellite polymorphism.
- 1999
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Ingår i: Am J Hum Genet. - 0002-9297. ; 64:6, s. 1709-18
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed the origin of allelic diversity at the class II HLA-DRB1 locus, using a complex microsatellite located in intron 2, close to the polymorphic second exon. A phylogenetic analysis of human, gorilla, and chimpanzee DRB1 sequences indicated that the structure of the microsatellite has evolved, primarily by point mutations, from a putative ancestral (GT)x(GA)y-complex-dinucleotide repeat. In all contemporary DRB1 allelic lineages, with the exception of the human *04 and the gorilla *08 lineages, the (GA)y repeat is interrupted, often by a G-->C substitution. In general, the length of the 3' (GA)y repeat correlates with the allelic lineage and thus evolves more slowly than a middle (GA)z repeat, whose length correlates with specific alleles within the lineage. Comparison of the microsatellite sequence from 30 human DRB1 alleles showed the longer 5' (GT)x to be more variable than the shorter middle (GA)z and 3' (GA)y repeats. Analysis of multiple samples with the same exon sequence, derived from different continents, showed that the 5' (GT)x repeat evolves more rapidly than the middle (GA)z and the 3' (GA)y repeats, which is consistent with findings of a higher mutation rate for longer tracts. The microsatellite-repeat-length variation was used to trace the origin of new DRB1 alleles, such as the new *08 alleles found in the Cayapa people of Ecuador and the Ticuna people of Brazil.
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| 50. |
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