Repetitive sequences
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The objective of this study was to characterize the virulence characteristics of a collection of Klebsiella pneumoniae isolates collected from different clinical sources. A collection of 60 non-repetitive K. pneumoniae isolates, was studied. In vitro, virulence was analyzed by testing the survival of bacteria in pooled human serum. Isolates were typed by MLST. The genomes of 23 K. pneumoniae isolates, representatives of different STs and virulence profiles, were completely sequenced using the Illumina platform. Of note, 26/60 of K. pneumoniae isolates were resistant to killing by complement. Serum-resistant isolates belonged to distinct STs. Analysis of WGS data with VFDB showed the presence of several virulence genes related various virulence functions. Specifically, serum-resistant isolates carried a higher number of ORFs, which were associated with serum resistance, compared to serum-sensitive isolates. Additionally, analysis of WGS data showed the presence of multiple plasmid replicons that could be involved with the spread and acquisition of resistance and virulence genes. In conclusion, analysis of virulence characteristics showed that an important percentage (31.6%) of K. pneumoniae isolates were in vitro virulent by exhibiting resistance to serum. Thus, the presence of several virulence factors, in combination with the presence of multidrug resistance, could challenge antimicrobial therapy of infections caused by such bacteria.
- MeSH
- faktory virulence * genetika MeSH
- genom bakteriální MeSH
- infekce bakteriemi rodu Klebsiella * mikrobiologie genetika MeSH
- Klebsiella pneumoniae * genetika patogenita izolace a purifikace MeSH
- lidé MeSH
- multilokusová sekvenční typizace MeSH
- nemocnice MeSH
- plazmidy genetika MeSH
- sekvenování celého genomu MeSH
- virulence genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Řecko MeSH
G-quadruplexes (G4s) are functional elements of the human genome, some of which inhibit DNA replication. We investigated replication of G4s within highly abundant microsatellite (GGGA, GGGT) and transposable element (L1 and SVA) sequences. We found that genome-wide, numerous motifs are located preferentially on the replication leading strand and the transcribed strand templates. We directly tested replicative polymerase ε and δ holoenzyme inhibition at these G4s, compared to low abundant motifs. For all G4s, DNA synthesis inhibition was higher on the G-rich than C-rich strand or control sequence. No single G4 was an absolute block for either holoenzyme; however, the inhibitory potential varied over an order of magnitude. Biophysical analyses showed the motifs form varying topologies, but replicative polymerase inhibition did not correlate with a specific G4 structure. Addition of the G4 stabilizer pyridostatin severely inhibited forward polymerase synthesis specifically on the G-rich strand, enhancing G/C strand asynchrony. Our results reveal that replicative polymerase inhibition at every G4 examined is distinct, causing complementary strand synthesis to become asynchronous, which could contribute to slowed fork elongation. Altogether, we provide critical information regarding how replicative eukaryotic holoenzymes navigate synthesis through G4s naturally occurring thousands of times in functional regions of the human genome.
- MeSH
- aminochinoliny MeSH
- DNA-polymerasa II * antagonisté a inhibitory metabolismus MeSH
- DNA-polymerasa III * antagonisté a inhibitory metabolismus MeSH
- DNA chemie MeSH
- G-kvadruplexy * MeSH
- genom lidský * MeSH
- holoenzymy metabolismus MeSH
- kyseliny pikolinové farmakologie MeSH
- lidé MeSH
- mikrosatelitní repetice MeSH
- proteiny vázající poly-ADP-ribosu MeSH
- replikace DNA * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Non-canonical (non-B) DNA structures-e.g. bent DNA, hairpins, G-quadruplexes (G4s), Z-DNA, etc.-which form at certain sequence motifs (e.g. A-phased repeats, inverted repeats, etc.), have emerged as important regulators of cellular processes and drivers of genome evolution. Yet, they have been understudied due to their repetitive nature and potentially inaccurate sequences generated with short-read technologies. Here we comprehensively characterize such motifs in the long-read telomere-to-telomere (T2T) genomes of human, bonobo, chimpanzee, gorilla, Bornean orangutan, Sumatran orangutan, and siamang. Non-B DNA motifs are enriched at the genomic regions added to T2T assemblies and occupy 9%-15%, 9%-11%, and 12%-38% of autosomes and chromosomes X and Y, respectively. G4s and Z-DNA are enriched at promoters and enhancers, as well as at origins of replication. Repetitive sequences harbor more non-B DNA motifs than non-repetitive sequences, especially in the short arms of acrocentric chromosomes. Most centromeres and/or their flanking regions are enriched in at least one non-B DNA motif type, consistent with a potential role of non-B structures in determining centromeres. Our results highlight the uneven distribution of predicted non-B DNA structures across ape genomes and suggest their novel functions in previously inaccessible genomic regions.
- MeSH
- DNA * chemie genetika MeSH
- G-kvadruplexy MeSH
- genom lidský MeSH
- genom * MeSH
- Hominidae * genetika MeSH
- lidé MeSH
- nukleotidové motivy MeSH
- Pan troglodytes genetika MeSH
- repetitivní sekvence nukleových kyselin MeSH
- telomery * genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The ReAct (Recovery, Activity) project is an ENFSI (European Network of Forensic Science Institutes) supported initiative comprising a large consortium of laboratories. Here, the results from more than 23 laboratories are presented. The primary purpose was to design experiments simulating typical casework circumstances; collect data and to implement Bayesian networks to assess the value (i.e., likelihood ratio) of DNA results given activity level propositions. Two different experimental designs were used to simulate a robbery, where a screwdriver was used to force a door or window. Propositions and case information were chosen following laboratory feedback listing typical casework circumstances (included in the paper). In a direct transfer experiment, the defendant owned and used the screwdriver, but he did not force the door/window in question. An unknown person used the defendant's stolen screwdriver. In an indirect transfer experiment, the defendant neither owned, saw, nor used the screwdriver, nor did they force the door or window. For the second experiment, given the defence view, the defendant never held the screwdriver. We envisaged the situation where an object manipulated by the defendant (or the defendant himself/herself) would be touched by the unknown offender who would then force the window. It was found for the direct transfer experiment that unless a single contributor profile aligning with the known person's of interest profile was retrieved, the results did not allow to discriminate between propositions. On the other hand, for the indirect transfer experiment, both single and major contributor profiles that aligned with the person of interest (POI) supported the proposition that the person used the tool rather than an unknown person who had touched an object, when indeed the former was true. There was considerable variation in median recoveries of DNA between laboratories (between 200pg-5ng) for a given experiment if quantities are taken into account. These differences affect the likelihood ratios given activity level propositions. More than 2700 samples were analysed in the course of this study. Two different Bayesian Networks are made available via an open source application written in Shiny R: Shiny_React(). For comparison, all datasets were analysed using a qualitative method categorised into absent, single, major or other given contributors. The importance of standardising methods is emphasised, alongside the necessity of developing new approaches to assign the probability of laboratory-dependent DNA recovery. Freely accessible open databases play a crucial role in supporting these efforts.
- MeSH
- Bayesova věta * MeSH
- DNA fingerprinting * MeSH
- DNA * genetika MeSH
- laboratoře * MeSH
- lidé MeSH
- mikrosatelitní repetice MeSH
- pravděpodobnostní funkce MeSH
- soudní genetika metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Abies guatemalensis Rehder, an endangered conifer endemic to Central American highlands, is ecologically vital in upper montane forests. It faces threats from habitat fragmentation, unsustainable logging, and illegal Christmas tree harvesting. While previous genetic studies on mature trees from eighteen populations showed high within-population diversity and limited among-population differentiation, the genetic impact of recent anthropogenic pressures on younger generations has yet to be discovered. Understanding these effects is crucial for developing effective conservation strategies for this vulnerable species. We sampled 170 young trees (< 15 years old) from seven populations across Guatemala. Seven microsatellite markers were used to analyse genetic diversity, population structure, and recent demographic history. Moderate levels of genetic diversity were observed within populations (mean Shannon diversity index = 4.97, mean Simpson's index = 0.51, mean allelic richness = 11.59, mean observed heterozygosity = 0.59). Although genetic structure broadly aligned with mountain corridors, substantial admixture patterns suggest historical connectivity across all populations. Most populations showed evidence of recent bottlenecks (p < 0.05) and inbreeding. The results suggest a potential decline in genetic diversity and increased population structuring (ΦST = 0.274, p < 0.01) over the past decades compared to the previous study on old trees. The observed genetic patterns indicate ongoing impacts of habitat fragmentation and anthropogenic pressures on A. guatemalensis. Conservation efforts should prioritise expanding effective population sizes and facilitating gene flow, particularly for isolated populations. While restoration efforts may be logistically easier within mountain ranges, genetic evidence suggests that increasing overall population connectivity could benefit this species. Management strategies should implement systematic seed collection protocols to maintain genetic diversity in future populations. These findings highlight the urgent need for conservation measures to preserve remaining genetic diversity and promote connectivity among A. guatemalensis populations.
- MeSH
- ekosystém * MeSH
- genetická variace * MeSH
- jedle * genetika MeSH
- mikrosatelitní repetice * genetika MeSH
- ohrožené druhy * MeSH
- populační genetika MeSH
- zachování přírodních zdrojů MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Guatemala MeSH
Satellite DNAs (satDNAs) are abundant components of eukaryotic genomes, playing pivotal roles in chromosomal organization, genome stability, and evolution. Here, we combined cytogenetic and genomic methods to characterize the satDNAs in the genomes of Leptidea butterflies. Leptidea is characterized by the presence of a high heterochromatin content, large genomes, and extensive chromosomal reshuffling as well as the occurrence of cryptic species. We show that, in contrast to other Lepidoptera, satDNAs constitute a considerable proportion of Leptidea genomes, ranging between 4.11% and 11.05%. This amplification of satDNAs, together with the hyperactivity of transposable elements, contributes to the substantial genome expansion in Leptidea. Using chromosomal mapping, we show that, particularly LepSat01-100 and LepSat03-167 satDNAs, are preferentially localized in heterochromatin exhibiting variable distribution that may have contributed to the highly diverse karyotypes within the genus. The satDNAs also exhibit W-chromosome accumulation, suggesting their involvement in sex chromosome evolution. Our results provide insights into the dynamics of satDNAs in Lepidoptera genomes and highlight their role in genome expansion and chromosomal organization, which could influence the speciation process. The high proportion of repetitive DNAs in the genomes of Leptidea underscores the complex evolutionary dynamics revealing the interplay between repetitive DNAs and genomic architecture in the genus.
BACKGROUND: The mammalian Natural Killer Complex (NKC) harbors genes and gene families encoding a variety of C-type lectin-like proteins expressed on various immune cells. The NKC is a complex genomic region well-characterized in mice, humans and domestic animals. The major limitations of automatic annotation of the NKC in non-model animals include short-read based sequencing, methods of assembling highly homologous and repetitive sequences, orthologues missing from reference databases and weak expression. In this situation, manual annotations of complex genomic regions are necessary. METHODS: This study presents a manual annotation of the genomic structure of the NKC region in a high-quality reference genome of the domestic cat and compares it with other felid species and with representatives of other carnivore families. Reference genomes of Carnivora, irrespective of sequencing and assembly methods, were screened by BLAST to retrieve information on their killer cell lectin-like receptor (KLR) gene content. Phylogenetic analysis of in silico translated proteins of expanded subfamilies was carried out. RESULTS: The overall genomic structure of the NKC in Carnivora is rather conservative in terms of its C-type lectin receptor gene content. A novel KLRH-like gene subfamily (KLRL) was identified in all Carnivora and a novel KLRJ-like gene was annotated in the Mustelidae. In all six families studied, one subfamily (KLRC) expanded and experienced pseudogenization. The KLRH gene subfamily expanded in all carnivore families except the Canidae. The KLRL gene subfamily expanded in carnivore families except the Felidae and Canidae, and in the Canidae it eroded to fragments. CONCLUSIONS: Knowledge of the genomic structure and gene content of the NKC region is a prerequisite for accurate annotations of newly sequenced genomes, especially of endangered wildlife species. Identification of expressed genes, pseudogenes and gene fragments in the context of expanded gene families would allow the assessment of functionally important variability in particular species.
- MeSH
- anotace sekvence MeSH
- buňky NK * imunologie metabolismus MeSH
- Carnivora * genetika MeSH
- fylogeneze * MeSH
- genom MeSH
- genomika * metody MeSH
- kočky genetika MeSH
- lektiny typu C genetika MeSH
- zvířata MeSH
- Check Tag
- kočky genetika MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
BACKGROUND: Transport protein particle (TRAPP) is a multiprotein complex that functions in localising proteins to the Golgi compartment. The TRAPPC11 subunit has been implicated in diseases affecting muscle, brain, eye and to some extent liver. We present three patients who are compound heterozygotes for a missense variant and a structural variant in the TRAPPC11 gene. TRAPPC11 structural variants have not yet been described in association with a disease. In order to reveal the estimated genesis of identified structural variants, we performed sequencing of individual breakpoint junctions and analysed the extent of homology and the presence of repetitive elements in and around the breakpoints. METHODS: Biochemical methods including isoelectric focusing on serum transferrin and apolipoprotein C-III, as well as mitochondrial respiratory chain complex activity measurements, were used. Muscle biopsy samples underwent histochemical analysis. Next-generation sequencing was employed for identifying sequence variants associated with neuromuscular disorders, and Sanger sequencing was used to confirm findings. RESULTS: We suppose that non-homologous end joining is a possible mechanism of deletion origin in two patients and non-allelic homologous recombination in one patient. Analyses of mitochondrial function performed in patients' skeletal muscles revealed an imbalance of mitochondrial metabolism, which worsens with age and disease progression. CONCLUSION: Our results contribute to further knowledge in the field of neuromuscular diseases and mutational mechanisms. This knowledge is important for understanding the molecular nature of human diseases and allows us to improve strategies for identifying disease-causing mutations.
- MeSH
- delece genu MeSH
- dítě MeSH
- dospělí MeSH
- kosterní svaly patologie metabolismus MeSH
- lidé MeSH
- missense mutace genetika MeSH
- svalové dystrofie * genetika patologie MeSH
- vysoce účinné nukleotidové sekvenování MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
Echinococcus granulosus (Batsch, 1786), a cestode of the Teniidae family, causes human cystic echinococcosis (CE) also known as hydatid disease. Echinococcus granulosus sensu lato includes the G1, G3, G4, G5, G6/7 and G8/10 genotypes which are known to cause human CE. This study aimed to differentiate genotypes of E. granulosus s.l. complex by employing EmsB, a tandemly repeated multilocus microsatellite, using next-generation sequencing (MIC-NGS). Human and animal histopathology-confirmed hydatid cyst tissue samples and reference DNA samples of E. granulosus G1, G3, G4, G5, G6/7 and G10 underwent MIC-NGS assay with custom primers amplifying a 151 bp EmsB DNA fragment. NGS data were analysed using online Galaxy analysis pipeline, a phylogenetic tree was constructed by MEGA software, and haplotype networking was performed with PopArt 1.7. All sixty samples (49 from animals and 11 from humans) included were successfully identified and genotyped with a 100 % success rate. The study showed improved discrimination power to distinguish all study samples including closely related E. granulosus s.s. genotypes G1-G3. The maximum likelihood tree reaffirmed the monophyly of E. granulosus s.l. The median-joining haplotype networking revealed 12 distinct haplotypes. In conclusion, MIC-NGS assay was shown to be sensitive, specific and simple to apply to clinical samples offering a powerful discriminatory tool for the genotyping of E. granulosus s.l.
- MeSH
- Echinococcus granulosus * genetika MeSH
- echinokokóza * veterinární parazitologie MeSH
- fylogeneze MeSH
- genotyp * MeSH
- genotypizační techniky veterinární MeSH
- lidé MeSH
- mikrosatelitní repetice * MeSH
- vysoce účinné nukleotidové sekvenování * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Despite the widely accepted involvement of DNA methylation in the regulation of rDNA transcription, the relative participation of different cytosine methylation pathways is currently described only for a few model plants. Using PacBio, Bisulfite, and RNA sequencing; PCR; Southern hybridizations; and FISH, the epigenetic consequences of rDNA copy number variation were estimated in two T. porrifolius lineages, por1 and por2, the latter with more than twice the rDNA copy numbers distributed approximately equally between NORs on chromosomes A and D. The lower rDNA content in por1 correlated with significantly reduced (>90%) sizes of both D-NORs. Moreover, two (L and S) prominent rDNA variants, differing in the repetitive organization of intergenic spacers, were detected in por2, while only the S-rDNA variant was detected in por1. Transcriptional activity of S-rDNA in por1 was associated with secondary constriction of both A-NORs. In contrast, silencing of S-rDNA in por2 was accompanied by condensation of A-NORs, secondary constriction on D-NORs, and L-rDNA transcriptional activity, suggesting (i) bidirectional nucleolar dominance and (ii) association of S-rDNAs with A-NORs and L-rDNAs with D-NORs in T. porrifolius. Each S- and L-rDNA array was formed of several sub-variants differentiating both genetically (specific SNPs) and epigenetically (transcriptional efficiency and cytosine methylation). The most significant correlations between rDNA silencing and methylation were detected for symmetric CWG motifs followed by CG motifs. No correlations were detected for external cytosine in CCGs or asymmetric CHHs, where methylation was rather position-dependent, particularly for AT-rich variants. We conclude that variations in rDNA copy numbers in plant diploids can be accompanied by prompt epigenetic responses to maintain an appropriate number of active rDNAs. The methylation dynamics of CWGs are likely to be the most responsible for regulating silent and active rDNA states.
- MeSH
- chromozomy rostlin genetika MeSH
- cytosin * metabolismus MeSH
- epigeneze genetická MeSH
- genetická transkripce MeSH
- metylace DNA * MeSH
- regulace genové exprese u rostlin MeSH
- ribozomální DNA * genetika MeSH
- umlčování genů * MeSH
- variabilita počtu kopií segmentů DNA MeSH
- Publikační typ
- časopisecké články MeSH