DNA Analysis Research Articles

Prenatal diagnostic errors in hemoglobin Bart's hydrops fetalis caused by rare genetic interactions of α-thalassemia.

To describe rare genetic interactions of α-thalassemia alleles causing Hb H disease and Hb Bart's hydrops fetalis which could lead to diagnostic errors in a routine practice. Hematological and molecular characterization were carried out in a Thai family with a risk of having fetus with Hb Bart's hydrops fetalis. Both parents were found to be the thalassemia intermedia patients associated with unusual forms of Hb H disease. DNA analysis of common α-thalassemia mutations in Thailand identified α+-thalassemia (-α3.7 kb del) and unknown α0-thalassemia in the father and α0-thalassemia (--SEA) with unknown α+-thalassemia in the mother. Fetal DNA analysis unlikely identified a homozygosity for α0-thalassemia (--SEA/--SEA). Further analysis identified that the father carried a rare South African α0-thalassemia in combination with α+-thalassemia (--SA/-α), whereas the mother was a patient with Hb H-Queens Park disease (--SEA/ααQP). The fetus was, in fact, a compound heterozygote for (--SA/--SEA). As shown in this study, routine screening for α-thalassemia at prenatal diagnosis in the region should include both common and rare α0-thalassemia alleles found in the population to effectively prevent a fatal condition of Hb Bart's hydrops fetalis syndrome.

Transcriptional profiling in microglia across physiological and pathological states identifies a transcriptional module associated with neurodegeneration

Microglia are the resident immune cells of the central nervous system and are involved in brain development, homeostasis, and disease. New imaging and genomics technologies are revealing microglial complexity across developmental and functional states, brain regions, and diseases. We curated a set of publicly available gene expression datasets from human microglia spanning disease and health to identify sets of genes reflecting physiological and pathological microglial states. We also integrated multiple human microglial single-cell RNA-seq datasets in Alzheimer’s disease (AD), multiple sclerosis (MS), and Parkinson’s disease, and identified a distinct microglial transcriptional signature shared across diseases. Analysis of germ-line DNA identified genes with variants associated with AD and MS that are overrepresented in microglial gene sets, including the disease-associated transcriptional signature. This work points to genes that are dysregulated in disease states and provides a resource for the analysis of diseases in which microglia are implicated by genetic evidence.

Bacteriophage λ exonuclease and a 5'-phosphorylated DNA guide allow PAM-independent targeting of double-stranded nucleic acids.

Sequence-specific recognition of double-stranded nucleic acids is essential for molecular diagnostics and in situ imaging. Clustered regularly interspaced short palindromic repeats and Cas systems rely on protospacer-adjacent motif (PAM)-dependent double-stranded DNA (dsDNA) recognition, limiting the range of targetable sequences and leading to undesired off-target effects. Using single-molecule fluorescence resonance energy transfer analysis, we discover the enzymatic activity of bacteriophage λ exonuclease (λExo). We show binding of 5'-phosphorylated single-stranded DNA (pDNA) to complementary regions on dsDNA and DNA-RNA duplexes, without the need for a PAM-like motif. Upon binding, the λExo-pDNA system catalytically digests the pDNA into nucleotides in the presence of Mg2+. This process is sensitive to mismatches within a wide range of the pDNA-binding region, resulting in exceptional sequence specificity and reduced off-target effects in various applications. The absence of a requirement for a specific motif such as a PAM sequence greatly broadens the range of targets. We demonstrate that the λExo-pDNA system is a versatile tool for molecular diagnostics, DNA computing and gene imaging applications.

Long-read de novo genome assembly of Gulf toadfish (Opsanus beta)

BackgroundThe family Batrachoididae are a group of ecologically important teleost fishes with unique life histories, behavior, and physiology that has made them popular model organisms. Batrachoididae remain understudied in the realm of genomics, with only four reference genome assemblies available for the family, with three being highly fragmented and not up to current assembly standards. Among these is the Gulf toadfish, Opsanus beta, a model organism for serotonin physiology which has recently been bred in captivity.ResultsHere we present a new, de novo genome and transcriptome assemblies for the Gulf toadfish using PacBio long read technology. The genome size of the final assembly is 2.1 gigabases, which is among the largest teleost genomes. This new assembly improves significantly upon the currently available reference for Opsanus beta with a final scaffold count of 62, of which 23 are chromosome scale, an N50 of 98,402,768, and a BUSCO completeness score of 97.3%. Annotation with ab initio and transcriptome-based methods generated 41,076 gene models. The genome is highly repetitive, with ~ 70% of the genome composed of simple repeats and transposable elements. Satellite DNA analysis identified potential telomeric and centromeric regions.ConclusionsThis improved assembly represents a valuable resource for future research using this important model organism and to teleost genomics more broadly.

Biosynthetic gene clusters from uncultivated soil bacteria of the Atacama Desert.

Soil microorganisms mediate several biological processes through the secretion of natural products synthesized in specialized metabolic pathways, yet functional characterization in ecological contexts remains challenging. Using culture-independent metagenomic analyses of microbial DNA derived directly from soil samples, we examined the potential of biosynthetic gene clusters (BGCs) from six bacterial communities distributed along an altitudinal gradient of the Andes Mountains in the Atacama Desert. We mined 38 metagenome-assembled genomes (MAGs) and identified 168 BGCs. Results indicated that most predicted BGCs were classified as non-ribosomal-peptides (NRP), post-translational modified peptides (RiPP), and terpenes, which were mainly identified in genomes of species from Acidobacteriota and Proteobacteria phyla. Based on BGC composition according to types of core biosynthetic genes, six clusters of MAGs were observed, three of them with predominance for a single phylum, of which two also showed specificity to a single sampling site. Comparative analyses of accessory genes in BGCs showed associations between membrane transporters and other protein domains involved in specialized metabolism with classes of biosynthetic cores, such as resistance-nodulation-cell division (RND) multidrug efflux pumps with RiPPs and the iron-dependent transporter TonB with terpenes. Our findings increase knowledge regarding the biosynthetic potential of uncultured bacteria inhabiting pristine locations from one of the oldest and driest nonpolar deserts on Earth.IMPORTANCEMuch of what we know about specialized metabolites in the Atacama Desert, including Andean ecosystems, comes from isolated microorganisms intended for drug development and natural product discovery. To complement research on the metabolic potential of microbes in extreme environments, comparative analyses on functional annotations of biosynthetic gene clusters (BGCs) from uncultivated bacterial genomes were carried out. Results indicated that in general, BGCs encode for structurally unique metabolites and that metagenome-assembled genomes did not show an obvious relationship between the composition of their core biosynthetic potential and taxonomy or geographic distribution. Nevertheless, some members of Acidobacteriota showed a phylogenetic relationship with specific metabolic traits and a few members of Proteobacteria and Desulfobacterota exhibited niche adaptations. Our results emphasize that studying specialized metabolism in environmental samples may significantly contribute to the elucidation of structures, activities, and ecological roles of microbial molecules.

The Barren Berry phenotype: untangling cranberry (Vaccinium macrocarpon Ait.) genetic contamination in central Wisconsin and beyond

Wisconsin is the world’s leading producer of cranberries (Vaccinium macrocarpon Ait.; 2n = 2x = 24). The state produces over twenty-thousand acres that contribute to more than 50% of the global total production, with more than one billion dollars in value. Cranberry growers in the “central sands” of Wisconsin have been experiencing yield decline due to vegetative unproductive genotypes, popularly known as “Barren Berry’’, which consistently remain vegetative and produce no fruit. The purpose of this study was to compare visual inspection in the field to DNA fingerprinting for the early detection of unproductive/barren genotypes. Additionally, the study served as a survey of unproductive genotypes in central Wisconsin, the largest growing region in the world. A total of 839 cranberry leaf samples, from 14 growers representing plantings to four cultivated varieties, were submitted for DNA testing of two visually determined phenotypes: unproductive or barren (n = 646; those that produced little to no fruit), versus productive or fruiting (n = 193). We conducted genetic fingerprinting on the leaf tissue using nine microsatellite markers previously shown to differentiate cranberry genotypes. This study identified a barren berry genotype unique to central Wisconsin, which we denoted “Barren Berry 1”. This genotype accounted for 43% of samples submitted as the barren berry phenotype. Genetic fingerprinting revealed sixty-five different genotypes in beds which were thought to be monocultures of just four cultivated genotypes. Early detection of genetic contamination through visual inspection, genetic testing, and responsible propagation can drastically aid in the management and longevity of cranberry beds, and in turn save time and money to the growers.

Targeted therapy guided by circulating tumor DNA analysis in advanced gastrointestinal tumors.

Although comprehensive genomic profiling has become standard in oncology for advanced solid tumors, the full potential of circulating tumor DNA (ctDNA)-based profiling in capturing tumor heterogeneity and guiding therapy selection remains underexploited, marked by a scarcity of evidence on its clinical impact and the assessment of intratumoral heterogeneity. The GOZILA study, a nationwide, prospective observational ctDNA profiling study, previously demonstrated higher clinical trial enrollment rates using liquid biopsy compared with tissue screening. This updated analysis of 4,037 patients further delineates the clinical utility of ctDNA profiling in advanced solid tumors, showcasing a significant enhancement in patient outcomes with a 24% match rate for targeted therapy. Patients treated with matched targeted therapy based on ctDNA profiling demonstrated significantly improved overall survival compared with those receiving unmatched therapy (hazard ratio, 0.54). Notably, biomarker clonality and adjusted plasma copy number were identified as predictors of therapeutic efficacy, reinforcing the value of ctDNA in reflecting tumor heterogeneity for precise treatment decisions. These new insights into the relationship between ctDNA characteristics and treatment outcomes advance our understanding beyond the initial enrollment benefits. Our findings advocate for the broader adoption of ctDNA-guided treatment, signifying an advancement in precision oncology and improving survival outcomes in advanced solid tumors.

Lake-centred sedentary lifestyle of early Tibetan Plateau Indigenous populations at high elevation 4,400 years ago.

The onset of sedentism on the Tibetan Plateau is often presumed to be associated with the dispersal of agriculture or farmers from archaeological sites located in the low elevation margins of the plateau. Previous studies of the plateau assumed that all foragers were probably mobile, but few systematic excavations at forager sites have been conducted to inform us about their settlement patterns. Here we report the world's highest elevation sedentary way of living exhibited by the Mabu Co site at 4,446 metres above sea level, deep in the interior of the Tibetan Plateau 4,400-4,000 years ago. Our interdisciplinary study indicates that the site was occupied by Indigenous inhabitants of the plateau, representing the earliest known DNA evidence of foragers who predominantly harbour the southern plateau ancestry. The evidence shows that they had a sedentary lifestyle primarily supported by fishing at nearby lakes, supplemented by mammal and bird hunting, as well as small-scale exchanges of millet and rice crops.

Abstract PR-04: Phase 2 Trial Testing The PARP Inhibitor Niraparib In Patients With Advanced Pancreatic Cancer with Pathogenic Variants In BRCA 1, BRCA2, PALB2, ATM and CHEK2

Abstract Background: Poly-(adenosine diphosphate ribose) polymerase (PARP) inhibitors have demonstrated efficacy in patients with platinum-sensitive pancreatic cancer who harbor germline BRCA 1/2 pathogenic variants (PVs). Whether PARP inhibitors are effective in a broader population of pancreatic cancer patients is still under investigation. Methods: This was a multicenter, single arm, open-label phase II trial (NCT03601923) investigating the use of the PARP inhibitor niraparib in patients with advanced pancreatic cancer. Eligible patients were required to have germline or somatic mutations in BRCA1, BRCA2, PALB2, ATM and/or CHEK2. Prior treatment with PARP inhibitors and prior progression on a platinum chemotherapy were not allowed, though patients could be included if they had progression on non-platinum based therapy. Patients were treated with weight-adjusted niraparib (200 mg or 300 mg) once daily on a 28-day cycle. The primary endpoint was 6-month progression free survival (PFS) rate (binary). Secondary endpoints were PFS, overall survival (OS), objective response rate (ORR) by RECIST v1.1, and safety. Serial plasma samples were collected for circulating tumor DNA analyses. Results: Thirty-two patients (10 females [31%]; median age 67) were evaluable for the primary endpoint. Patients had a germline or somatic alteration in one or more of the following genes: ATM (n=14), BRCA2 (n=10), PALB2 (n=3), CHEK2 (n=4), or BRCA1 (n=2). There were 10 patients who received niraparib as maintenance therapy and 12 patients whose tumors previously progressed on a non-platinum-based chemotherapy. The 6-month PFS rate was 25% (90% CI: 13-41), rejecting the null hypothesis of a 17% 6-month PFS rate. The median PFS for the entire population was 2.0 months (90% CI: 1.7-3.7) and median OS was 10.2 months (90% CI: 8.2-13.2). The objective response rate was 14% (90% CI: 5-30%); 2 patients had a complete response, 2 patients had a partial response. Patients who never previously progressed on chemotherapy had a significantly longer median PFS (p=0.02) and OS (p=0.003) than patients who previously progressed on chemotherapy. Three patients with biallelic inactivation of ATM, who never progressed on prior lines of chemotherapy, were on niraparib for over 1 year (range 1 – 4 years). Reversion mutations restoring the reading frame in BRCA2 were identified in cell-free DNA in 3 patients with BRCA2 pathogenic frameshift variants. Additional putative resistance mutations in other DNA repair genes were identified and will be reported. Conclusions: Niraparib demonstrated a promising 6-month PFS rate and provided clinically meaningful benefit in patients with pancreatic cancer. The observation of prolonged benefit of three patients with biallelic ATM inactivation warrants further investigation. Acknowledgment: Funding for this study was provided by GSK. GSK was provided the opportunity to review a preliminary version of this abstract for factual accuracy. The authors are solely responsible for final content and interpretation. Citation Format: Brandon M. Huffman, Jett Crowdis, Matthew B. Yurgelun, Nora Horick, Yvonne Li, Huy Nguyen, Kalindi Parmar, Bose S. Kochupurakkal, Andrea Enzinger, Marios Giannakis, Nadine McCleary, Kimmie Ng, Anuj K. Patel, Kimberly J. Perez, Douglas A. Rubinson, Benjamin L. Schlechter, Harshabad Singh, Helen Lam, Kaitlyn Ramsey, Elizabeth Andrews, Leigh Culnane, Andrea Bullock, Ahmed Rattani, Jeffrey Clark, Mary Linton Peters, Brian M. Wolpin, Alan D. D'Andrea, Geoffrey I. Shapiro, Andrew J. Aguirre, James M. Cleary. Phase 2 Trial Testing The PARP Inhibitor Niraparib In Patients With Advanced Pancreatic Cancer with Pathogenic Variants In BRCA 1, BRCA2, PALB2, ATM and CHEK2 [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr PR-04.

Whole Mitochondrial Genome Sequencing Analysis of Canine Testicular Tumours

Currently, the molecular background based on mitochondrial DNA (mtDNA) analysis of canine testicular tumours is underestimated. The available data mostly focus on histopathological evaluations, with a few reports of nuclear genome (nDNA) studies. Tumourigenesis represents a highly complex and diverse genetic disorder, which can also encompass defects in mtDNA. The aim of this study was to identify molecular changes in whole mitochondrial genome sequences obtained from dogs affected by testicular tumours. Samples of blood, tumour, and healthy tissue were collected from each animal, and mtDNA (ultimately 45 samples) was subsequently sequenced. Thereafter, protein analyses were performed to assess the impact of the identified molecular alterations on the amino acid level. The total number of observed changes included 722 SNPs, 12 mutations, 62 indels, 5 indel mutations, and 35 heteroplasmic sites. The highest number of mtDNA variants in protein-coding genes COX1, COX3, ATP6, ND1, ND4, and ND5 was observed. Interestingly, SNPs were found in 10 out of 22 tRNA genes. Most of the identified mtDNA defects were synonymous changes at the amino acid level. Also, polymorphisms and heteroplasmy were frequently observed in the variable number of tandem repeat (VNTR) regions, especially in its fragment spanning 16,138–16,358 bp. Based on the obtained results, it was possible to select 11 polymorphisms that occurred in all the tested samples (benign, malignant) and an additional five SNPs identified only in benign neoplasms. The comprehensive analysis of malignant testicular tumours demonstrated a significant diversity in their molecular profiles, with changes ranging from 17 to 101 per sample.

The prevalence of mutations underlying development of Helicobacter pylori resistance to antibiotics in Kazan

Background. One of the reasons for the decrease of Helicobacter pylori eradication effectiveness is its resistance to antibiotics. Aim. To examine the prevalence of H. pylori point mutations responsible for clarithromycin and levofloxacin resistance among the patients with upper gastrointestinal (GI) tract disorders in Kazan. Materials and methods. The study included 203 patients with symptoms of dyspepsia who underwent upper GI endoscopy at the University Hospital of Kazan Federal University (Kazan, Russia) in 2019–2021. DNA isolation from gastric antrum mucosal biopsies was performed using PureLink Genomic DNA Mini Kits (Thermo Fisher Scientific, USA). Polymerase chain reaction was performed using primers specific for the V-region of the 23S gene and the A subunit DNA gyrase encoding gyrA gene region. The sequencing of obtained DNA fragments was performed on 3730 DNA Analyzer. The sequences were searched for point mutations responsible for H. pylori resistance to clarithromycin (A2143G, A2142G and A2142C193 mutations) and levofloxacin (mutations of the gyrA gene). Results. H. pylori was detected in 47.78% of biopsy specimens using polymerase chain reaction. The proportion of H. pylori strains with mutations leading to clarithromycin resistance was 17.53%. Amino acid substitutions in the gyrA gene were found in 12.37% of samples. In case of two H. pylori strains (2.06%), dual resistance to clarithromycin and levofloxacin was found. Conclusion. So high incidence of mutations underlying the development of H. pylori resistance to clarithromycin and levofloxacin was observed among examined patients in Kazan.

Advancing Cancer Care in Colombia: Results of the First In Situ Implementation of Comprehensive Genomic Profiling

Background: Comprehensive genomic profiling (CGP) identifies genetic alterations and patterns that are crucial for therapy selection and precise treatment development. In Colombia, limited access to CGP tests underscores the necessity of documenting the prevalence of treatable genetic alterations. This study aimed to describe the somatic genetic profile of specific cancer types in Colombian patients and assess its impact on treatment selection. Methods: A retrospective cohort study was conducted at Clínica Colsanitas S.A. from March 2023 to June 2024. Sequencing was performed on the NextSeq2000 platform with the TruSight Oncology 500 (TSO500) assay, which simultaneously evaluates 523 genes for DNA analysis and 55 for RNA; additionally, analyses were performed with the SOPHiA DDM software. The tumor mutational burden (TMB), microsatellite instability (MSI), and programmed cell death ligand 1 (PDL1) were assessed. Results: Among 111 patients, 103 were evaluated, with gastrointestinal (27.93%), respiratory (13.51%), and central nervous system cancers (10.81%) being the most prevalent. TP53 (37%), KMT2C (28%), and KRAS (21%) were frequent mutations. Actionable findings were detected in 76.7% of cases, notably in digestive (20 patients) and lung cancers (8 patients). MSI was stable at 82.52% and high at 2.91%, whilst TMB was predominantly low (91.26%). Conclusions: The test has facilitated access to targeted therapies, improving clinical outcomes in Colombian patients. This profiling test is expected to increase opportunities for personalized medicine in Colombia.

Age estimation of burnt human remains through DNA methylation analysis.

The identification of human fire victims is a challenging task in forensic medicine. The heat-induced alterations of biological tissues can make the conventional anthropological analyses difficult. Even if the DNA profile of the victim is achieved, it is possible that no match can be found in a forensic DNA database, thus hindering positive identification. In such cases, any information useful to nail down a possible identity should be collected, such as DNA methylation analysis which could provide useful investigative leads. In the present study, five age-related epigenetic markers (ELOVL2, FHL2, KLF14, C1orf132, and TRIM59) were initially analysed in blood samples of 72 living Italian individuals of known age, using a Single Base Extension (SBE) assay. An age prediction model was built by multiple linear regression including all the markers (Mean Absolute Error, MAE: 3.15 years). This model was tested on 29 blood samples collected during autopsies from burnt human remains, already identified through DNA analysis, providing a MAE of 6.92 years. The model allowed a correct prediction in 79.3% of the cases (95% prediction interval), while six cases were associated with inaccurate predictions (min-max prediction error: 9.8-37.3 years). Among the different sample variables considered to explain these results, only the DNA degradation index was a relevant factor affecting the reliability of the predictions. In conclusion, the SBE typing of blood from burnt remains proved to be a reliable tool to estimate chronological age of most of the samples, also in consideration of its cost-effectiveness and the availability of CE sequencers in every forensic genetics laboratory.

Genomic profiling of cell-free DNA from dogs with benign and malignant tumors

ObjectiveCancer is currently the most common cause of death in adult dogs. Like humans, dogs have a one-third chance of developing cancer in their lifetime. We used shallow whole-genome sequencing (sWGS) to analyze blood cell-free DNA (cfDNA) from four tumor-bearing dogs (one with benign and three with malignant tumors) and 38 healthy dogs.ResultsSimilar to the results observed in the healthy dogs, no copy number aberration (CNA) was detected in the dog with benign lipomas, and the distribution of cfDNA fragment size (FS) closely resembled that of the healthy dogs. However, among the three dogs diagnosed with malignant tumors, two dogs exhibited varying degrees and quantities of CNAs. Compared to the distribution of FS in the healthy dogs, the cancer dogs exhibited a noticeable shift towards shorter lengths. These findings indicated that CNA and FS profiles derived from sWGS data can be used for non-invasive cancer detection in dogs.

Pheno- and genotypic epidemiological characterization of Staphylococcus aureus isolated from bulk tank milk in Colombia

Staphylococcus aureus is recognized for causing contagious mastitis in cattle. Elimination of the organism in affected animals is challenging due to its potential antibiotic resistance mechanisms and virulence factors. The aim of the study was the pheno- and genotypic epidemiological characterization of S. aureus isolated from bulk tank milk samples obtained from three municipalities in the northern region of Antioquia. Twenty-one S. aureus isolates from 150 bulk tank milk samples were characterized by evaluating antimicrobial susceptibility to 17 antibiotics using the VITEK 2, and identifying several genes encoding for virulence factors, enterotoxins, and the agr groups by conventional PCR. The clonal relationship between the isolates was assessed using macrorestriction fragment analysis (MRFA) of chromosomal DNA by pulsed-field gel electrophoresis (PFGE). Most of the isolates showed susceptibility to the tested antibiotics; 19% exhibited resistance to tetracycline and all isolates showed beta-lactamases. Molecular typing revealed that 76% carried the agrI and cap5 genes. Seven isolates harbored genes coding for staphylococcal enterotoxins (SE), with seh being the most identified gene. Furthermore, MRFA demonstrated high heterogeneity among the isolates, resulting in the assignment of 18 different MRFA patterns. These results indicate phenotypic resistance to tetracycline and beta-lactams, the presence of genes encoding for staphylococcal enterotoxins, and high heterogeneity among S. aureus isolates from bulk tank milk.

Biochemically Programmable Isothermal PCR.

Isothermal PCR can be performed by imposing a static temperature gradient that continuously circulates reagents through denaturing, annealing, and extension conditions inside a PCR tube. But despite early promise, these systems have yet to demonstrate performance and repeatability sufficient for adoption in validated laboratory tests because the rate-limiting extension step is inherently short and cannot be increased independently of the other stages in a temperature cycle. Here, a discovery that enables isothermal PCR to be achieved with statistically robust repeatability that meets or exceeds diagnostic assay requirements (false positive/negative rate <8% at 95% confidence) by manipulating the interplay between the DNA replication biochemistry (via the amplicon GC content) and the microscale circulatory flow inside a PCR tube is reported. Surprisingly, optimal performance depends on selecting primer sequences that replicate high GC content amplicons, contradicting established PCR primer design rules. This innovative thermocycling approach accelerates PCR to speeds rivaling ultra-fast instruments, enabling rapid, repeatable isothermal DNA analysis across a range of targets relevant to diagnostics and pathogen detection.

Blobs form during the single-file transport of proteins across nanopores

The transport of biopolymers across nanopores is an important biological process currently under investigation for the rapid analysis of DNA and proteins. While the transport of DNA is generally understood, methods to induce unfolded protein translocation have only recently been discovered (Yu et al., 2023, Sauciuc et al., 2023). Here, we found that during electroosmotically driven translocation of polypeptides, blob-like structures typically form inside nanopores, often obstructing their transport and preventing addressing individual amino acids. This is in contrast with the electrophoretic transport of DNA, where the formation of such structures has not been reported. Comparisons between different nanopore sizes and shapes and modifications by different surface chemistries allowed formulating a mechanism for blob formation. We also show that single-file transport can be achieved by using 1) nanopores that have an entry and an internal diameter smaller than the persistence length of the polymer, 2) nanopores with a nonsticky (i.e., nonaromatic) inner surface, and 3) moderate translocation velocities. These experiments provide a basis for understanding polypeptide transport under confinement and for improving the design and engineering of nanopores for protein analysis.

Methodological assessment for efficient collection of Schistosoma mansoni environmental DNA and improved schistosomiasis surveillance in tropical wetlands

Schistosomiasis, caused by trematodes of genus Schistosoma, is among the most seriously neglected tropical diseases. Although rapid surveillance of risk areas for Schistosoma transmission is vital to control schistosomiasis, the habitat and infection status of this parasite are difficult to assess. Environmental DNA (eDNA) analysis, involving the detection of extra-organismal DNA in water samples, facilitates cost-efficient and sensitive biomonitoring of aquatic environments and is a promising tool to identify Schistosoma habitat and infection risk areas. However, in tropical wetlands, highly turbid water causes filter clogging, thereby decreasing the filtration volume and increasing the risk of false negatives. Therefore, in this study, we aimed to conduct laboratory experiments and field surveys in Lake Victoria, Mbita, to determine the appropriate filter pore size for S. mansoni eDNA collection in terms of particle size and filtration volume. In the laboratory experiment, aquarium water was sequentially filtered using different pore size filters. Targeting >3 µm size fraction was found to be sufficient to capture S. mansoni eDNA particles, regardless of their life cycle stage (egg, miracidia, and cercaria). In the field surveys, GF/D (2.7 µm nominal pore size) filter yielded 2.5-times the filtration volume obtained with a smaller pore size filter and pre-filtration methods under the same time constraints. Moreover, a site-occupancy model was applied to the field detection results to estimate S. mansoni eDNA occurrence and detection probabilities and assess the number of water samples and PCR replicates necessary for efficient eDNA detection. Overall, this study reveals an effective method for S. mansoni eDNA detection in turbid water, facilitating the rapid and sensitive monitoring of its distribution and cost-effective identification of schistosomiasis transmission risk areas.

Molecular diagnostics of familial hypercholesterolemia in Russia: yesterday, today and tomorrow

Familial hypercholesterolemia is a severe hereditary disease leading to the development of atherosclerosis and its complications in the form of angina pectoris, myocardial infarction, cerebral stroke, or even leading to sudden death. Since the description of the disease, the concept of it has undergone significant evolution. First, it became clear that the prevalence of this disease was significantly higher than originally thought (1:300 for heterozygous familial hypercholesterolemia and not as 1:500 as estimated earlier). Secondly, it has been established that it is not based on the pathology of the low-density lipoprotein receptor gene alone, but includes at least four monogenic forms (defects of the APOB, PCSK9, ARH genes) and may also have a multigenic nature. Thirdly, with the development of DNA analysis methods from the initially available Southern hybridization to next generation DNA sequencing, the exceptional molecular heterogeneity of familial hypercholesterolemia became obvious and, accordingly, the need to establish national spectra of mutations leading to the development of familial hypercholesterolemia was established. Researchers have moved from characterizing individual mutations to creating national registries and databases. Finally, research into the genetics of familial hypercholesterolemia has led to the emergence of new classes of cholesterol-lowering drugs. In Russia, molecular diagnostics of familial hypercholesterolemia has also undergone significant changes since the beginning of the study of familial hypercholesterolemia in 1987 and to the present, consideration of these changes formed the basis of this review.

A comprehensive evaluation of Cell Elution Method (CEM) for forensic DNA analysis from smoked cigarettes

Cigarette stubs are commonly encountered trace DNA samples at crime scenes. Standard laboratory practice typically involves direct lysis of the stub for DNA extraction, leading to the co-extraction of DNA-degrading and inhibiting constituents from smoke and tobacco. This process can result in lower-quality DNA profiles. There has been limited focus on developing specific sample processing techniques that minimize these degrading agents and inhibitors before DNA extraction, which could significantly enhance the quality of DNA profiles. This study evaluates a previously established Cell Elution Method (CEM) against the conventional Direct Lysis Method (DLM) for DNA extraction from cigarette stubs. DNA quantity, quality, and subsequent STR profiles were assessed in 80 smoked cigarette stubs, comprising both flavoured and unflavoured types. While CEM exhibited comparable DNA yield from both flavoured (0.17 ng) and unflavoured (0.19 ng) cigarettes, DLM showed significant variability in average DNA yield for unflavoured (0.05 ng) and for flavoured (0.25 ng) cigarettes. Notably, CEM-treated samples demonstrated lower Degradation Index (DI) values compared to DLM-treated ones for both the types of cigarettes. Consequently, STR profiling success rates were higher with CEM, with 95 % of flavoured and 55 % of unflavoured samples yielding informative profiles, compared to 80 % and 0 %, respectively, for DLM. In unflavoured stubs, Amelogenin marker amplification was achieved in 35 % of CEM-treated samples, significantly outperforming the 5 % success rate with DLM. Additionally, CEM resulted in higher average allele recovery rates for both flavoured (58.98 %) and unflavoured (33.41 %) samples compared to DLM. These findings indicate that CEM outperforms DLM in producing higher-quality DNA profiles from cigarette stubs. Thus, CEM can be a choice of method for processing cigarette stub prior to DNA extraction.