| 1. |
- Abi-Rached, Laurent, et al.
(författare)
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The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans
- 2011
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 334:6052, s. 89-94
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Tidskriftsartikel (refereegranskat)abstract
- Whole genome comparisons identified introgression from archaic to modern humans. Our analysis of highly polymorphic human leukocyte antigen (HLA) class I, vital immune system components subject to strong balancing selection, shows how modern humans acquired the HLA-B*73 allele in west Asia through admixture with archaic humans called Denisovans, a likely sister group to the Neandertals. Virtual genotyping of Denisovan and Neandertal genomes identified archaic HLA haplotypes carrying functionally distinctive alleles that have introgressed into modern Eurasian and Oceanian populations. These alleles, of which several encode unique or strong ligands for natural killer cell receptors, now represent more than half the HLA alleles of modern Eurasians and also appear to have been later introduced into Africans. Thus, adaptive introgression of archaic alleles has significantly shaped modern human immune systems.
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| 2. |
- Babrzadeh, Farbod, et al.
(författare)
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Whole-genome sequencing of the efficient industrial fuel-ethanol fermentative Saccharomyces cerevisiae strain CAT-1
- 2012
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Ingår i: Molecular Genetics and Genomics. - : Springer Science and Business Media LLC. - 1617-4615 .- 1617-4623. ; 287:6, s. 485-494
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Tidskriftsartikel (refereegranskat)abstract
- The Saccharomyces cerevisiae strains widely used for industrial fuel-ethanol production have been developed by selection, but their underlying beneficial genetic polymorphisms remain unknown. Here, we report the draft whole-genome sequence of the S. cerevisiae strain CAT-1, which is a dominant fuel-ethanol fermentative strain from the sugarcane industry in Brazil. Our results indicate that strain CAT-1 is a highly heterozygous diploid yeast strain, and the similar to 12-Mb genome of CAT-1, when compared with the reference S228c genome, contains similar to 36,000 homozygous and similar to 30,000 heterozygous single nucleotide polymorphisms, exhibiting an uneven distribution among chromosomes due to large genomic regions of loss of heterozygosity (LOH). In total, 58 % of the 6,652 predicted protein-coding genes of the CAT-1 genome constitute different alleles when compared with the genes present in the reference S288c genome. The CAT-1 genome contains a reduced number of transposable elements, as well as several gene deletions and duplications, especially at telomeric regions, some correlated with several of the physiological characteristics of this industrial fuel-ethanol strain. Phylogenetic analyses revealed that some genes were likely associated with traits important for bioethanol production. Identifying and characterizing the allelic variations controlling traits relevant to industrial fermentation should provide the basis for a forward genetics approach for developing better fermenting yeast strains.
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| 3. |
- Eriksson, Jonas, et al.
(författare)
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Pyrosequencing (TM) technology at elevated temperature
- 2004
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Ingår i: Electrophoresis. - : Wiley. - 0173-0835 .- 1522-2683. ; 25:1, s. 20-27
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Tidskriftsartikel (refereegranskat)abstract
- To date, the Pyrosequencing(TM) technology has been performed at 28degreesC due to the low thermostability of the firefly luciferase. In this study, firefly luciferase was stabilized in the presence of glycine betaine, allowing DNA sequencing at 37degreesC. By increasing the temperature to 37degreesC, false signals due to primer-dimers and loop-structures were decreased significantly. In addition, a combination of (i) replacing the natural dGTP with 7'deaza-dGTP in the polymerase chain reaction (PCR), (ii) 1.6 m glycine betaine, and (iii) an increase of the temperature to 37degreesC enabled us to sequence a DNA template with the initial sequence 3'-ATGGCCCGGGGGGGAGCTCCA . . . 5'. Furthermore, we describe a method to analyze if a primer forms a primer-dimer with extendable 3'-ends.
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| 4. |
- Eriksson, Jonas, et al.
(författare)
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Pyrosequencing trade mark technology at elevated temperature
- 2004
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Ingår i: Electrophoresis. - : Wiley-VCH Verlagsgesellschaft. - 0173-0835 .- 1522-2683. ; 25:1, s. 20-27
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Tidskriftsartikel (refereegranskat)abstract
- To date, the Pyrosequencing trade mark technology has been performed at 28 degrees C due to the low thermostability of the firefly luciferase. In this study, firefly luciferase was stabilized in the presence of glycine betaine, allowing DNA sequencing at 37 degrees C. By increasing the temperature to 37 degrees C, false signals due to primer-dimers and loop-structures were decreased significantly. In addition, a combination of (i) replacing the natural dGTP with 7'deaza-dGTP in the polymerase chain reaction (PCR), (ii) 1.6 M glycine betaine, and (iii) an increase of the temperature to 37 degrees C enabled us to sequence a DNA template with the initial sequence 3'-ATGGCCCGGGGGGGAGCTCCA em leader 5'. Furthermore, we describe a method to analyze if a primer forms a primer-dimer with extendable 3'-ends.
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| 5. |
- Gambelunghe, G., et al.
(författare)
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Lack of association of human chemokine receptor gene polymorphisms CCR2-64I and CCR5-Delta 32 with autoimmune Addison's disease
- 2004
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Ingår i: European journal of immunogenetics. - : Wiley. - 0960-7420 .- 1365-2370. ; 31:2, s. 73-76
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Tidskriftsartikel (refereegranskat)abstract
- The attraction of leukocytes to tissues is essential for inflammation and the initiation of the autoimmune reaction. The process is controlled by chemokines, which are chemotactic cytokines. We investigated whether human chemokine receptor gene polymorphisms, namely CCR5-Delta32 and CCR2-64I, are associated with susceptibility to autoimmune Addison's disease. Genotyping was performed in 56 patients and 127 healthy controls by a new method using pyrosequencing for CCR2-64I and by polymerase chain reaction and detecting gel for CCR5-Delta32. None of the CCR2 or CCR5 alleles was found to be associated, either positively or negatively, with disease risk. Our results indicate that the CCR2-64I and CCR5-Delta32 gene polymorphisms do not play a major role in conferring genetic risk for, and/or protection against, autoimmune Addison's disease.
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| 6. |
- Ghaderi, Mehran, et al.
(författare)
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MHC2TA single nucleotide polymorphism and genetic risk for autoimmune adrenal insufficiency
- 2006
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 91:10, s. 4107-4111
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: The polymorphism of class II HLA genes modulates the genetic risk for several endocrine autoimmune diseases. The constitutive class II expression on antigen-presenting cells is under the control of the MHC class II transactivator, encoded by the MHC2TA gene, which is mapped to chromosome 16p13. The MHC2TA -168 A-->G single nucleotide polymorphism (rs3087456) has been suggested to confer susceptibility to some autoimmune diseases. DESIGN: With the aim of testing whether this MHC2TA single nucleotide polymorphism is independently associated with autoimmune Addison's disease (AAD) and/or modulates the genetic risk conferred by DRB1-DQA1-DQB1 haplotypes, we analyzed DNA samples from 128 AAD patients and 406 healthy control subjects from continental Italy. RESULTS: Frequency of allele G of MHC2TA was significantly increased among AAD patients (39% alleles), compared with 29% in healthy controls (P = 0.003). Similarly, the frequency of AG+GG genotypes was significantly higher among AAD patients than among healthy control subjects, in both a codominant (P = 0.012) and a G-dominant model (P = 0.018). Multivariate logistic regression analysis showed that MHC2TA AG+GG continued to be positively associated with genetic risk for AAD (P = 0.028, odds ratio = 1.72, 95% confidence interval = 1.06-2.78), after correction for DRB1*03-DQA1*0501-DQB1*0201, DRB1*04 (not 0403)-DQA1*0301-DQB1*0302 and DRB1*0403. Similar results were obtained when the number of G alleles was included in the model (P = 0.004; odds ratio = 1.65, 95% confidence interval = 1.17-2.32). CONCLUSIONS: Our study provides the first demonstration of the association of the polymorphism of the MHC2TA gene with genetic risk for AAD that appears to be independent from the well-known association with the polymorphism of HLA class II genes.
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| 7. |
- Gharizadeh, Baback, et al.
(författare)
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Detection of gyrA mutations associated with ciprofloxacin resistance in Neisseria gonorrhoeae by rapid and reliable pre-programmed short DNA sequencing
- 2005
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Ingår i: International Journal of Antimicrobial Agents. - : Elsevier BV. - 0924-8579 .- 1872-7913. ; 26:6, s. 486-490
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Tidskriftsartikel (refereegranskat)abstract
- Quinolone resistance is rapidly increasing in Neisseria gonorrhoeae and is posing a significant public health threat that requires constant surveillance. A rapid and reliable mutation detection assay has been developed. The assay is based on pre-programmed short DNA sequencing and is designed to detect point mutations in the gyrA gene that are highly related to ciprofloxacin resistance, i.e. in codons 91 and 95. By developing an assay based on pyrosequencing and exploiting the pre-programmed nucleotide dispensation capability of this technology, the sequence comprising the mutations will be analysed and promptly reveal whether the N. gonorrhoeae pathogen carries resistance to ciprofloxacin. A panel of 40 N. gonorrhoeae clinical isolates, of which 27 phenotypically displayed decreased susceptibility or resistance to ciprofloxacin, was used in the present study. All point mutations in the short stretch of the N. gonorrhoeae gyrA gene were easily discriminated, and the genotypic results obtained by pre-programmed sequencing were mainly in agreement with the phenotypically identified decreased susceptibility or resistance to ciprofloxacin. The new method used in the present study has the potential for rapid and reliable identification of known as well as previously unknown drug resistance mutations.
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| 8. |
- Gharizadeh, Baback, et al.
(författare)
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Identification of medically important fungi by the Pyrosequencing (TM) technology
- 2004
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Ingår i: Mycoses. - : Wiley. - 0933-7407 .- 1439-0507. ; 47:1-2, s. 29-33
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Tidskriftsartikel (refereegranskat)abstract
- The Pyrosequencing(TM) technology was used for identification of different clinically relevant fungi. The tests were performed on amplicons derived from the 18S rRNA gene using polymerase chain reaction (PCR) universal primers for amplification. Sequencing was performed up to 40 bases in a variable region with a designed general sequencing primer and the Pyrosequence data were analyzed by BLAST sequence search in the GenBank database. DNA from a total of 21 fungal specimens consisting of nine strains of clinically relevant fungi and 12 clinical specimens from patients suffering from proven invasive fungal infections were PCR-amplified and analyzed by gel electrophoresis, PCR-enzyme-linked immunosorbent assay (ELISA) and the Pyrosequencing technology. All data obtained by the Pyrosequencing technology were in agreement with the results obtained by PCR-ELISA using species/genus-specific oligonucleotides and were as well in accordance with the culture results. The results demonstrate that the Pyrosequencing method is a reproducible and reliable technique for identification of fungal pathogens.
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| 9. |
- Gharizadeh, Baback, 1967-
(författare)
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Method development and applications of Pyrosequencing technology
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The ability to determine nucleic acid sequences is one ofthe most important platforms for the detailed study ofbiological systems. Pyrosequencing technology is a relativelynovel DNA sequencing technique with multifaceted uniquecharacteristics, adjustable to different strategies, formatsand instrumentations. The aims of this thesis were to improvethe chemistry of the Pyrosequencing technique for increasedread-length, enhance the general sequence quality and improvethe sequencing performance for challenging templates. Improvedchemistry would enable Pyrosequencing technique to be used fornumerous applications with inherent advantages in accuracy,flexibility and parallel processing.Pyrosequencing technology, at its advent, was restricted tosequencing short stretches of DNA. The major limiting factorwas presence of an isomer of dATPaS, a substitute for thenatural dATP, which inhibited enzyme activity in thePyrosequencing chemistry. By removing this non-functionalnucleotide, we were able to achieve DNA read-lengths of up toone hundred bases, which has been a substantial accomplishmentfor performance of different applications. Furthermore, the useof a new polymerase, called Sequenase, has enabled sequencingof homopolymeric T-regions, which are challenging for thetraditional Klenow polymerase. Sequenase has markedly madepossible sequencing of such templates with synchronizedextension.The improved read-length and chemistry has enabledadditional applications, which were not possible previously.DNA sequencing is the gold standard method for microbial andvial typing. We have utilized Pyrosequencing technology foraccurate typing ofhuman papillomaviruses, and bacterial andfungal identification with promising results.Furthermore, DNA sequencing technologies are not capable oftyping of a sample harboring a multitude of species/types orunspecific amplification products. We have addressed theproblem of multiple infections/variants present in a clinicalsample by a new versatile method. The multiple sequencingprimer method is suited for detection and typing of samplesharboring different clinically important types/species(multiple infections) and unspecific amplifications, whicheliminates the need for nested PCR, stringent PCR conditionsand cloning. Furthermore, the method has proved to be usefulfor samples containing subdominant types/species, and sampleswith low PCR yield, which avoids reperforming unsuccessfulPCRs. We also introduce the sequence pattern recognition whenthere is a plurality of genotypes in the sample, whichfacilitates typing of more than one target DNA in the sample.Moreover, target specific sequencing primers could be easilytailored and adapted according to the desired applications orclinical settings based on regional prevalence ofmicroorganisms and viruses.Pyrosequencing technology has also been used forclone-checking by using preprogrammed nucleotide additionorder, EST sequencing and SNP analysis, yielding accurate andreliable results.Keywords:apyrase, bacterial identification, dATPaS, ESTsequencing, fungal identification, human papillomavirus (HPV),microbial and viral typing, multiple sequencing primer method,Pyrosequencing technology, Sequenase, single-strandedDNA-binding protein (SSB), SNP analysis
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| 10. |
- Gharizadeh, Baback, et al.
(författare)
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Methodological improvements of pyrosequencing technology
- 2006
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 0168-1656 .- 1873-4863. ; 124:3, s. 504-511
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Tidskriftsartikel (refereegranskat)abstract
- Pyrosequencing technology is a rather novel DNA sequencing method based on the sequencing-by-synthesis principle. This bioluminometric, real-time DNA sequencing technique employs a cascade of four enzymatic reactions producing sequence peak signals. The method has been proven highly suitable for single nucleotide polymorphism analysis and sequencing of short stretches of DNA. Although the pyrosequencing procedure is relatively straightforward, users may face challenges due to varying parameters in PCR and sequencing primer design, sample preparation and nucleotide dispensation; such challenges are labor and cost intensive. In this study, these issues have been addressed to increase signal quality and assure sequence accuracy.
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