| 1. |
- Kesarimangalam, Sriram, 1983, et al.
(författare)
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High diversity of bla NDM-1 -encoding plasmids in Klebsiella pneumoniae isolated from neonates in a Vietnamese hospital
- 2022
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Ingår i: International Journal of Antimicrobial Agents. - : Elsevier BV. - 1872-7913 .- 0924-8579. ; 59:2
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The carbapenemase-encoding gene blaNDM-1 has been reported in Vietnam during the last 10 years, and blaNDM-producing Enterobacteriaceae are now silently and rapidly spreading. A key factor behind dissemination of blaNDM-1 is plasmids, mobile genetic elements that commonly carry antibiotic resistance genes and spread via conjugation. The diversity of blaNDM-1-encoding plasmids from neonates at a large Vietnamese hospital was characterized in this study. Methods: 18 fecal Klebsiella pneumoniae and Klebsiella quasipneumoniae isolates collected from 16 neonates at a large pediatric hospital in Vietnam were studied using optical DNA mapping (ODM) and next-generation sequencing (NGS). Plasmids carrying the blaNDM-1 gene were identified by combining ODM with Cas9 restriction. The plasmids in the isolates were compared to investigate whether the same plasmid was present in different patients. Results: Although the same plasmid was found in some isolates, ODM confirmed that there were at least 10 different plasmids encoding blaNDM-1 among the 18 isolates, thus indicating wide plasmid diversity. The ODM results concur with the NGS data. Interestingly, some isolates had two distinct plasmids encoding blaNDM-1 that could be readily identified with ODM. The coexistence of different plasmids carrying the same blaNDM-1 gene in a single isolate has rarely been reported, probably because of limitations in plasmid characterization techniques. Conclusions: The plasmids encoding the blaNDM-1 gene in this study cohort were diverse and may represent a similar picture in Vietnamese society. The study highlights important aspects of the usefulness of ODM for plasmid analysis.
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| 2. |
- Sandling, Johanna K., et al.
(författare)
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A candidate gene study of the type I interferon pathway implicates IKBKE and IL8 as risk loci for SLE
- 2011
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Ingår i: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 19:4, s. 479-484
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Tidskriftsartikel (refereegranskat)abstract
- Systemic Lupus Erythematosus (SLE) is a systemic autoimmune disease in which the type I interferon pathway has a crucial role. We have previously shown that three genes in this pathway, IRF5, TYK2 and STAT4, are strongly associated with risk for SLE. Here, we investigated 78 genes involved in the type I interferon pathway to identify additional SLE susceptibility loci. First, we genotyped 896 single-nucleotide polymorphisms in these 78 genes and 14 other candidate genes in 482 Swedish SLE patients and 536 controls. Genes with P<0.01 in the initial screen were then followed up in 344 additional Swedish patients and 1299 controls. SNPs in the IKBKE, TANK, STAT1, IL8 and TRAF6 genes gave nominal signals of association with SLE in this extended Swedish cohort. To replicate these findings we extracted data from a genomewide association study on SLE performed in a US cohort. Combined analysis of the Swedish and US data, comprising a total of 2136 cases and 9694 controls, implicates IKBKE and IL8 as SLE susceptibility loci (P(meta)=0.00010 and P(meta)=0.00040, respectively). STAT1 was also associated with SLE in this cohort (P(meta)=3.3 × 10(-5)), but this association signal appears to be dependent of that previously reported for the neighbouring STAT4 gene. Our study suggests additional genes from the type I interferon system in SLE, and highlights genes in this pathway for further functional analysis.
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| 3. |
- Klingström, Tomas, et al.
(författare)
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Legal & ethical compliance when sharing biospecimen
- 2018
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Ingår i: Briefings in Functional Genomics & Proteomics. - Oxford : Oxford University Press. - 2041-2649 .- 2041-2657. ; 17:1, s. 1-7
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Forskningsöversikt (refereegranskat)abstract
- When obtaining samples from biobanks, resolving ethical and legal concerns is a time-consuming task where researchers need to balance the needs of privacy, trust and scientific progress. The Biobanking and Biomolecular Resources Research Infrastructure-large Prospective Cohorts project has resolved numerous such issues through intense ommunication between involved researchers and experts in its mission to unite large rospective study sets in Europe. To facilitate efficient communication, it is useful for onexperts to have an at least basic understanding of the regulatory systemformanaging biological samples. Laws regulating research oversight are based on national law and normally share core principles founded on international charters. In interview studies among donors, chief concerns are privacy, efficient sample utilization and access to information generated fromtheir samples. Despite a lack of clear evidence regarding which concern takes precedence, scientific as well as public discourse has largely focused on privacy concerns and the right of donors to control the usage of their samples. It is therefore important to roactively deal with ethical and legal issues to avoid complications that delay or prevent samples from being accessed. To help biobank professionals avoid making unnecessary mistakes, we have developed this basic primer covering the relationship between ethics and law, the concept of informed consent and considerations for returning findings to donors.
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| 4. |
- Johansson, Anna Maria, et al.
(författare)
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Variation in the VWF Gene in Swedish Patients with Type 1 von Willebrand Disease.
- 2011
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Ingår i: Annals of Human Genetics. - : Wiley. - 1469-1809 .- 0003-4800. ; 75, s. 447-455
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Tidskriftsartikel (refereegranskat)abstract
- The spectrum of mutations in the von Willebrand factor (VWF) gene in a Swedish type 1 von Willebrand disease (VWD) population was investigated. To gain more knowledge about the dynamics of VWD mutations, the data were analyzed from a population genetics perspective. The VWF gene was resequenced in 54 Swedish patients diagnosed with type 1 VWD. Fifty-five variable sites were located in exons, 10 in the promoter and 38 in introns. The spectrum of mutations was similar to a European study, but included 10 new candidate mutations. The synonymous sites were evenly distributed along the coding sequence, whereas nonsynonymous sites were located into three clusters. Overall, 44% of patients had no mutations or candidate mutations and no promoter haplotype was significantly associated with disease. In 11 patients (20%), more than one mutation or candidate mutation was detected. The allelic identity for the putative disease-causing mutations was approximately 0.1, compatible with an overall disease frequency of 1%. VWF sequences for exon 28 from eight monkey species were compared with the variable positions found in our patients. Positions classified as mutations were overrepresented among sites that were fixed in all eight monkey species. No general increase of the mutation rate was found for the pseudogene region.
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| 5. |
- Ka, Sojeong, et al.
(författare)
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Differentially expressed genes in hypothalamus in relation to genomic regions under selection in two chicken lines resulting from divergent selection for high or low body weight
- 2011
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Ingår i: Neurogenetics. - : Springer Science and Business Media LLC. - 1364-6745 .- 1364-6753. ; 12:3, s. 211-221
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Tidskriftsartikel (refereegranskat)abstract
- Long-term divergent selection for low or high body weight from the same founder population has generated two extremely divergent lines of chickens, the high- (HWS) and low-weight (LWS) selected lines. At selection age (56 days), the lines differ by more than nine times in body weight. The HWS line chickens are compulsive feeders, whereas in the LWS line, some individuals are anorexic and others have very low appetite. Previous studies have implicated the central nervous system and particularly the hypothalamus in these behavioural differences. Here, we compared the mRNA expression in hypothalamus tissue from chickens on day 4 post-hatch using oligonucleotide arrays and found that the divergent selection had resulted in minor but multiple expression differences. Differentially expressed genes were enriched in processes 'DNA metabolism, repair, induction of apoptosis and metabolism'. Several differentially expressed genes participate in the regulation of neuronal plasticity and development, including apoptosis, or are neurotransmittor receptor subtypes. Less change was seen when comparing hypothalamic neuropeptide mediators of appetite such as the melanocortin receptors. The genomic locations of these differentially expressed genes were then compared to the locations of growth QTLs and to a genome-wide map of chromosomal regions that have been under divergent selection between the lines. The results indicate which differentially expressed hypothalamic genes have responded to the divergent selection and that the results predict that it is more likely to find causative genes among these most differentially expressed genes. Because of such differential gene expression in hypothalamus, the lines may adapt behaviourally different particularly to the post-hatch situation when independent feeding to obtain energy is established.
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| 6. |
- Feng, Chungang, et al.
(författare)
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A cis-Regulatory Mutation of PDSS2 Causes Silky-Feather in Chickens
- 2014
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 10:8, s. e1004576-
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Tidskriftsartikel (refereegranskat)abstract
- Silky-feather has been selected and fixed in some breeds due to its unique appearance. This phenotype is caused by a single recessive gene (hookless, h). Here we map the silky-feather locus to chromosome 3 by linkage analysis and subsequently fine-map it to an 18.9 kb interval using the identical by descent (IBD) method. Further analysis reveals that a C to G transversion located upstream of the prenyl (decaprenyl) diphosphate synthase, subunit 2 (PDSS2) gene is causing silky-feather. All silky-feather birds are homozygous for the G allele. The silky-feather mutation significantly decreases the expression of PDSS2 during feather development in vivo. Consistent with the regulatory effect, the C to G transversion is shown to remarkably reduce PDSS2 promoter activity in vitro. We report a new example of feather structure variation associated with a spontaneous mutation and provide new insight into the PDSS2 function.
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| 7. |
- Petersson, J, et al.
(författare)
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Importance and regulation of the colonic mucus barrier in a mouse model of colitis.
- 2011
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Ingår i: American journal of physiology. Gastrointestinal and liver physiology. - : American Physiological Society. - 1522-1547 .- 0193-1857. ; 300:2
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Tidskriftsartikel (refereegranskat)abstract
- The colonic mucus layer serves as an important barrier and prevents colonic bacteria from invading the mucosa and cause inflammation. The regulation of colonic mucus secretion is poorly understood. The aim of this study was to investigate the role of the mucus barrier in induction of colitis. Furthermore, regulation of mucus secretion by luminal bacterial products was studied. The colon of anesthetized Muc2(-/-), Muc1(-/-), wild-type (wt), and germ-free mice was exteriorized, the mucosal surface was visualized, and mucus thickness was measured with micropipettes. Colitis was induced by DSS (dextran sodium sulfate, 3%, in drinking water), and disease activity index (DAI) was assessed daily. The colonic mucosa of germ-free and conventionally housed mice was exposed to the bacterial products LPS (lipopolysaccharide) and PGN (peptidoglycan). After DSS induction of colitis, the thickness of the firmly adherent mucus layer was significantly thinner after 5 days and onward, which paralleled the increment of DAI. Muc2(-/-) mice, which lacked firmly adherent mucus, were predisposed to colitis, whereas Muc1(-/-) mice were protected with significantly lower DAI by DSS compared with wt mice. The mucus barrier increased in Muc1(-/-) mice in response to DSS, whereas significantly fewer T cells were recruited to the inflamed colon. Mice housed under germ-free conditions had an extremely thin adherent colonic mucus layer, but when exposed to bacterial products (PGN or LPS) the thickness of the adherent mucus layer was quickly restored to levels observed in conventionally housed mice. This study demonstrates a correlation between decreasing mucus barrier and increasing clinical symptoms during onset of colitis. Mice lacking colonic mucus (Muc2(-/-)) were hypersensitive to DSS-induced colitis, whereas Muc1(-/-) were protected, probably through the ability to increase the mucus barrier but also by decreased T cell recruitment to the afflicted site. Furthermore, the ability of bacteria to regulate the thickness of the colonic mucus was demonstrated.
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| 8. |
- Sun, Ren, et al.
(författare)
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Thymidine kinase 2 mutations in autosomal recessive progressive external ophthalmoplegia with multiple mitochondrial DNA deletion
- 2012
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 21, s. 66-75
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Tidskriftsartikel (refereegranskat)abstract
- Autosomal-inherited progressive external ophthalmoplegia (PEO) is an adult-onset disease characterized bytheaccumulation ofmultiple mitochondrial DNA(mtDNA) deletionsin post-mitotictissues.Mutations in six dif-ferent genes have been described to cause the autosomal dominant form of the disease, but only mutations inthe DNA polymerase gamma gene are known to cause autosomal recessive PEO (arPEO), leaving the geneticbackground of arPEO mostly unknown. Here we used whole-exome sequencing and identified compound het-erozygous mutations, leading to two amino acid alterations R225W and a novel T230A in thymidine kinase 2(TK2)inarPEOpatients.TK2isanenzymeofthemitochondrialnucleotidesalvagepathwayanditsloss-of-func-tion mutations have previously been shown to underlie the early-infantile myopathic form of mtDNA depletionsyndrome (MDS).Our TK2 activity measurementsof patient fibroblastsand mutant recombinant proteinsshowthat the combination of the identified arPEO variants, R225W and T230A, leads to a significant reduction in TK2activity, consistent with the late-onset phenotype, whereas homozygosity for R225W, previously associatedwith MDS, leads to near-total loss of activity. Our finding identifies a new genetic cause of arPEO with multiplemtDNA deletions. Furthermore, MDS and multiple mtDNA deletion disorders are manifestations of the samepathogenic pathways affecting mtDNA replication andrepair, indicating that MDS-associated genes shouldbe studied when searching for genetic background of PEO disorders.
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| 9. |
- McCue, Molly E., et al.
(författare)
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A High Density SNP Array for the Domestic Horse and Extant Perissodactyla : Utility for Association Mapping, Genetic Diversity, and Phylogeny Studies
- 2012
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 8:1, s. e1002451-
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Tidskriftsartikel (refereegranskat)abstract
- An equine SNP genotyping array was developed and evaluated on a panel of samples representing 14 domestic horse breeds and 18 evolutionarily related species. More than 54,000 polymorphic SNPs provided an average inter-SNP spacing of similar to 43 kb. The mean minor allele frequency across domestic horse breeds was 0.23, and the number of polymorphic SNPs within breeds ranged from 43,287 to 52,085. Genome-wide linkage disequilibrium (LD) in most breeds declined rapidly over the first 50-100 kb and reached background levels within 1-2 Mb. The extent of LD and the level of inbreeding were highest in the Thoroughbred and lowest in the Mongolian and Quarter Horse. Multidimensional scaling (MDS) analyses demonstrated the tight grouping of individuals within most breeds, close proximity of related breeds, and less tight grouping in admixed breeds. The close relationship between the Przewalski's Horse and the domestic horse was demonstrated by pair-wise genetic distance and MDS. Genotyping of other Perissodactyla (zebras, asses, tapirs, and rhinoceros) was variably successful, with call rates and the number of polymorphic loci varying across taxa. Parsimony analysis placed the modern horse as sister taxa to Equus przewalski. The utility of the SNP array in genome-wide association was confirmed by mapping the known recessive chestnut coat color locus (MC1R) and defining a conserved haplotype of similar to 750 kb across all breeds. These results demonstrate the high quality of this SNP genotyping resource, its usefulness in diverse genome analyses of the horse, and potential use in related species.
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| 10. |
- Lundtoft, Christian, et al.
(författare)
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Relation between HLA and copy number variation of steroid 21-hydroxylase in a Swedish cohort of patients with autoimmune Addison's disease.
- 2023
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Ingår i: European journal of endocrinology. - : Bioscientifica. - 1479-683X .- 0804-4643. ; 189:2, s. 235-241
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Tidskriftsartikel (refereegranskat)abstract
- Autoantibodies against the adrenal enzyme 21-hydroxylase is a hallmark manifestation in autoimmune Addison's disease (AAD). Steroid 21-hydroxylase is encoded by CYP21A2, which is located in the human leucocyte antigen (HLA) region together with the highly similar pseudogene CYP21A1P. A high level of copy number variation is seen for the 2 genes, and therefore, we asked whether genetic variation of the CYP21 genes is associated with AAD.Case-control study on patients with AAD and healthy controls.Using next-generation DNA sequencing, we estimated the copy number of CYP21A2 and CYP21A1P, together with HLA alleles, in 479 Swedish patients with AAD and autoantibodies against 21-hydroxylase and in 1393 healthy controls.With 95% of individuals carrying 2 functional 21-hydroxylase genes, no difference in CYP21A2 copy number was found when comparing patients and controls. In contrast, we discovered a lower copy number of the pseudogene CYP21A1P among AAD patients (P = 5 × 10-44), together with associations of additional nucleotide variants, in the CYP21 region. However, the strongest association was found for HLA-DQB1*02:01 (P = 9 × 10-63), which, in combination with the DRB1*04:04-DQB1*03:02 haplotype, imposed the greatest risk of AAD.We identified strong associations between copy number variants in the CYP21 region and risk of AAD, although these associations most likely are due to linkage disequilibrium with disease-associated HLA class II alleles.
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