Fragment Length Research Articles

Application of SSR markers for assessment of genetic similarity and genotype identification in local winter wheat breeding program

Background. Simple sequence repeat (SSR) markers are widely used for genetic analysis in plant breeding, allowing for the investigation of genetic divergence and similarity of genotypes, identification of unique alleles and determination of levels of genetic diversity. Materials and Methods. Analysis of 42 wheat cultivars and lines from the bree­ding program of Poltava State Agrarian University was carried out using 11 SSR mar­kers located on different chromosomes. A set of 11 microsatellite single locus primer pairs was used in this study (Xgwm 11, Xgwm 44, Xgwm 46, Xgwm 135, Xgwm 174, Xgwm 186, Xgwm 194, Xgwm 219, Xgwm 312, Xgwm 372, Xgwm 389). Amplification of 11 loci was performed using the Kapa2G FastHotStart PCR Kit (Kapa Biosystems, Boston, USA). The mixture for PCR amplification contained 1.5 x Kapa2G buffer, 0.5 mM dNTP mix, 0.5 μM of each primer (Sigma-Aldrich), 1 unit of Kapa2G FastHotStart DNA Polymerase and 11.8 ng of template DNA in a volume of 25 μl. Fragment lengths were determined using GeneMapper 4.0 software (Applied Biosystems). Dendrogram was constructed using UPGMA (unweighted pair-group method with arithmetic average) in DarWin 6.0 software (Perrier and Jacquemoud-Collet 2006) for clustering analysis. Results and Discussion. The number of alleles detected per locus varied from 5 (Xgwm 11, Xgwm 135, Xgwm 219) to 12 (Xgwm 174). A total of 80 alleles were identified for the 11 loci studied. Among these, 25 unique alleles were found, each of which was present in only one genotype. The polimorphism information content (PIC) values ranged from 0.48 to 0.87. The markers Xgwm 174 (PIC = 0.87), Xgwm 389 (PIC = 0.84) and Xgwm 372 (PIC = 0.83) were the most polymorphic in our study. We obtained a distribution of cultivars and lines by genetic similarity into five clusters. Conclusion. The use of SSR markers made it possible to identify rare alleles within the varieties presented. The study of the genetic similarity of the presented geno­types showed their relationship according to their origin. It was shown that unique alleles tended to occur in certain local breeding genotypes. This study has shown that genotypes representing the local Ukrainian breeding program often have the same allelic variants and at the same time some genotypes have unique allelic variants. The results obtained from the study of 42 winter wheat genotypes based on 11 SSR markers showed that molecular markers can be very useful in assessing genetic similarity and identifying genotypes in the local breeding program.

Early Changes in Tumor-Naive Cell-Free Methylomes and Fragmentomes Predict Outcomes in Pembrolizumab-Treated Solid Tumors.

Analysis of methylation and fragment length in plasma using cfMeDIP-seq provides a tumor-naive approach to measure ctDNA with results comparable with a tumor-informed bespoke ctDNA. Early kinetics within the first weeks of treatment in methylation and fragment quantity can predict outcomes with pembrolizumab in patients with various advanced solid tumors. This article is featured in Selected Articles from This Issue, p. 897.

Modeling the effect of temperature on rhizome sprouting in the invasive weed silverleaf nightshade (Solanum elaeagnifolium)

AbstractSilverleaf nightshade (Solanum elaeagnifolium Cav.), a noxious, highly invasive perennial weed, poses a significant threat to irrigated summer crops, vegetables, and orchards. This weed has the ability to reproduce both sexually through seed production and asexually via an extensive underground rhizome network, the latter playing a major role in the weed’s invasion, establishment, and persistence. Our aims were thus to assess the impact of temperature on rhizome sprouting for fragments of different lengths and to model the sprouting dynamics. The influence of temperature on the sprouting of rhizome fragments (2.5-, 5-, 7.5-, or 10-cm long) was investigated in growth chambers at eight temperatures ranging from 10 to 45 C. The highest sprouting proportions for 10-cm rhizome fragments were recorded at 30 and 35 C in complete darkness. The highest sprouting time for all fragment lengths was observed at 15 C in complete darkness. Modeling sprouting rates as a function of temperature gave the cardinal temperatures for the four different rhizome fragment lengths, with Tb (base temperature) values of 12.80, 9.34, 9.14, and 9.50 C, To (optimal temperature) values of 38.9 $$0$$ , 36.60, 35.16, and 34.86 C, and Tc (ceiling temperature) values of 39.80, 40.08, 40.50, and 40.80 C for rhizome lengths of 2.5, 5, 7.5, and 10 cm, respectively. Based on these findings, the potential for S. elaeagnifolium to spread to new areas and possible new management strategies are discussed; these offer a novel approach for informed decision making regarding the control of this weed.

Predicting disease recurrence in limited disease small cell lung cancer using cell-free DNA-based mutation and fragmentome analyses.

Limited disease (LD) small cell lung cancer (SCLC) treated with definitive concurrent chemoradiotherapy (CCRT) potentially experience disease recurrence. We investigated the feasibility of circulating-tumor DNA (ctDNA)-based genomic and fragmentome analyses to assess the risk of recurrence. Targeted sequencing was conducted using pre-treatment and on-treatment blood samples from definitive CCRT-treated patients with LD-SCLC (n=50). Based on 12-month recurrence-free survival (RFS), patients were categorized into persistent-response (PeR, n=29) and non-PeR (n=21) groups. Fragmentome analysis was conducted using ctDNA fragments of different lengths: P1 (100-155 bp) and P2 (160-180 bp). Patients with TP53 (n=15) and RB1 (n=11) mutation in on-treatment samples demonstrated significantly shorter RFS than patients with wild-type (WT) (P=0.05, P=0.0014, respectively). Fragmentome analysis of all available on-treatment samples (n=26) revealed that the non-PeR group (n=10) had a significantly higher P1 range (P=0.003) and lower P2 range (P=0.002). The areas under the curves for P1, P2, and the fragmentation ratio (P1/P2) in distinguishing the PeR and non-PeR were 0.850, 0.725, and 0.900, respectively. Using optimal cut-off, longer RFSs were found with the low-fragmentation-ratio group than with the high-fragmentation-ratio group (not reached vs. 7.6 months, P=0.002). Patients with both WT RB1 and a low-fragmentation-ratio (n=10) showed better outcomes than patients with both mutated RB1 and a high-fragmentation-ratio (n=10; hazard ratio, 7.55; 95% confidence interval: 2.14-26.6; P=0.002). RB1 mutations and high fragmentation ratios correlated with early disease recurrence. Analyzing ctDNA could help in predicting early treatment failure and making clinical decisions for high-risk patients.

Integration of Cell-Free DNA End Motifs and Fragment Lengths Can Identify Active Genes in Liquid Biopsies.

Multiple studies have shown that cell-free DNA (cfDNA) from cancer patients differ in both fragment length and fragment end motif (FEM) from healthy individuals, yet there is a lack of understanding of how the two factors combined are associated with cancer and gene transcription. In this study, we conducted cfDNA fragmentomics evaluations using plasma from lung cancer patients (n = 12) and healthy individuals (n = 7). A personal gene expression profile was established from plasma using H3K36me3 cell-free chromatin immunoprecipitation sequencing (cfChIP-seq). The genes with the highest expression displayed an enrichment of short cfDNA fragments (median = 19.99%, IQR: 16.94-27.13%, p < 0.0001) compared to the genes with low expression. Furthermore, distinct GC-rich FEMs were enriched after cfChIP. Combining the frequency of short cfDNA fragments with the presence of distinct FEMs resulted in an even further enrichment of the most expressed genes (median = 37.85%, IQR: 30.10-39.49%, p < 0.0001). An in vitro size selection of <150 bp cfDNA could isolate cfDNA representing active genes and the size-selection enrichment correlated with the cfChIP-seq enrichment (Spearman r range: 0.499-0.882, p < 0.0001). This study expands the knowledge regarding cfDNA fragmentomics and sheds new light on how gene activity is associated with both cfDNA fragment lengths and distinct FEMs.

Buffered Lugol's Iodine Preserves DNA Fragment Lengths.

Museum collections play a pivotal role in the advancement of biological science by preserving phenotypic and genotypic history and variation. Recently, contrast-enhanced X-ray computed tomography (CT) has aided these advances by allowing improved visualization of internal soft tissues. However, vouchered specimens could be at risk if staining techniques are destructive. For instance, the pH of unbuffered Lugol's iodine (I2KI) may be low enough to damage deoxyribonucleic acid (DNA). The extent of this risk is unknown due to a lack of rigorous evaluation of DNA quality between control and experimental samples. Here, we used formalin-fixed mice to document DNA concentrations and fragment lengths in nonstained, ethanol-preserved controls and 3 iodine-based staining preparations: (1) 1.25% weight-by-volume (wt/vol.) alcoholic iodine (I2E); (2) 3.75% wt/vol. I2KI; and (3) 3.75% wt/vol. buffered I2KI. We tested a null hypothesis of no significant difference in DNA concentrations and fragment lengths between control and treatment samples. We found that DNA concentration decreases because of staining-potentially an effect of measuring intact double-stranded DNA only. Fragment lengths, however, were significantly higher for buffered I2KI and control samples, which were not, themselves, significantly different. Our results implicate buffered I2KI as the appropriate choice for contrast-enhanced CT imaging of museum wet collections to safely maximize their potential for understanding genetic and phenotypic diversity.

MOBFinder: a tool for mobilization typing of plasmid metagenomic fragments based on a language model.

Mobilization typing (MOB) is a classification scheme for plasmid genomes based on their relaxase gene. The host ranges of plasmids of different MOB categories are diverse, and MOB is crucial for investigating plasmid mobilization, especially the transmission of resistance genes and virulence factors. However, MOB typing of plasmid metagenomic data is challenging due to the highly fragmented characteristics of metagenomic contigs. We developed MOBFinder, an 11-class classifier, for categorizing plasmid fragments into 10 MOB types and a nonmobilizable category. We first performed MOB typing to classify complete plasmid genomes according to relaxase information and then constructed an artificial benchmark dataset of plasmid metagenomic fragments (PMFs) from those complete plasmid genomes whose MOB types are well annotated. Next, based on natural language models, we used word vectors to characterize the PMFs. Several random forest classification models were trained and integrated to predict fragments of different lengths. Evaluating the tool using the benchmark dataset, we found that MOBFinder outperforms previous tools such as MOBscan and MOB-suite, with an overall accuracy approximately 59% higher than that of MOB-suite. Moreover, the balanced accuracy, harmonic mean, and F1-score reached up to 99% for some MOB types. When applied to a cohort of patients with type 2 diabetes (T2D), MOBFinder offered insights suggesting that the MOBF type plasmid, which is widely present in Escherichia and Klebsiella, and the MOBQ type plasmid might accelerate antibiotic resistance transmission in patients with T2D. To the best of our knowledge, MOBFinder is the first tool for MOB typing of PMFs. The tool is freely available at https://github.com/FengTaoSMU/MOBFinder.

Predictive factors in the retrieval of endodontic instruments: the relationship between the fragment length and location

Predictive factors in the retrieval of endodontic instruments: the relationship between the fragment length and location

Inactivation of the TIM complex components leads to a decrease in the level of DNA import into Arabidopsis mitochondria.

The phenomenon of DNA import into mitochondria has been shown for all major groups of eukaryotes. In plants and animals, DNA import seems to occur in different ways. It has been known that nucleic acids enter plant organelles through alternative channels, depending on the size of the imported molecules. Mitochondrial import of small DNA (up to 300 bp) partially overlaps with the mechanism of tRNA import, at least at the level of the outer membrane. It is noteworthy that, in plants, tRNA import involves components of the protein import apparatus, whose role in DNA transport has not yet been studied. In this work, we studied the role of individual components of the TIM inner membrane translocase in the process of DNA import into isolated Arabidopsis mitochondria and their possible association with the porin VDAC1. Using knockout mutants for the genes encoding Tim17 or Tim23 protein isoforms, we demonstrated for the first time the involvement of these proteins in the import of DNA fragments of different lengths. In addition, inhibition of transport channels with specific antibodies to VDAC1 led to a decrease in the level of DNA import into wild-type mitochondria, which made it possible to establish the specific involvement of this porin isoform in DNA import. In the tim17-1 knockout mutant, there was an additional decrease in the efficiency of DNA import in the presence of antibodies to VDAC1 compared to the wild type line. The results obtained indicate the involvement of the Tim17-1 and Tim23-2 proteins in the mechanism of DNA import into plant mitochondria. At the same time, Tim23-2 may be part of the channel formed with the participation of VDAC1, while Tim17-1, apparently, is involved in an alternative DNA import pathway independent of VDAC1. The identification of membrane carrier proteins involved in various DNA import pathways will make it possible to use the natural ability of mitochondria to import DNA as a convenient biotechnological tool for transforming the mitochondrial genome.

Performance of a Liquid Biopsy Diagnostic Prediction Model for EBV-Positive Burkitt Lymphoma in Sub-Saharan Africa

Burkitt Lymphoma (BL) is classified into EBV-positive BL (EBL) and EBV-negative BL (sporadic BL), the former being more prevalent in SSA (Al-Khreisat et al 2023). Conventional diagnosis of BL depends on the morphological assessment of invasive tissue biopsy followed by immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) to reveal the pathognomonic t(8;14), or t(8;22) translocations. This is associated with significant diagnostic delay in regions with limited pathology services (Mawalla et al 2023), often necessitating initiation of treatment based on clinical or histopathological findings without immunohistochemistry (Ogwang et al 2011), with ensuing mismanagement contributing to poor survival outcomes observed in SSA compared to High-Income Countries (HIC) (Sung et al 2021). Here, we sought to explore whether liquid biopsy could be used as an initial diagnostic aid for EBL in settings without easy access to pathology using different EBV DNA parameters and the MYC-Immunoglobulin ( MYC-Ig) gene rearrangement. This prospective study collected whole blood samples prospectively from 221 participants (90 BL and 131 non-BL) enrolled in the Aggressive Infection-Related East Africa Lymphoma (AI-REAL) project (Legason et al 2022) across 5 sites in Tanzania and Uganda. The revised BL diagnostic algorithm (Naresh et al 2021) was used as a gold-standard diagnosis. CfDNA was extracted using the QIAamp Circulating Nucleic Acid Kit (Qiagen, USA), according to the manufacturer's instructions. DNA libraries were prepared with the Thru PLEX Tag-Seq HV kit (Takara Bio Inc. Japan), and hybridization capture was performed using a custom, next-generation sequencing (NGS) panel targeting genes commonly mutated in BL and three EBV genes: EBER1, EBER2, and EBNA2. All sequencing was performed in-country (MiSeq, Illumina, CA, USA) and analyzed in a custom pipeline. Using custom scripts, EBV DNA copies per cell and EBV DNA fragment size ratio were calculated as the proportion of EBV fragments of length 180 - 200 base pairs (bp) divided by the proportion of autosomal fragments within the same size window. The diversity in the fragment size distribution of the EBV and autosomal DNA was calculated and presented as EBV entropy and autosomal entropy. Translocations were called using IgCaller (Nadeu et al 2020) and Genomic Rearrangement Identification Software Suite (GRIDSS) (Cameron et al 2017). Univariate analysis was performed to assess the association between predictor variables (clinical parameters, EBV parameters, and MYC translocation) and a diagnosis of EBL. Ten-fold cross-validation was performed on a liquid biopsy model consisting of all the liquid biopsy variables with the clinical variables included in the model as covariates. Performance metrics for the liquid biopsy model as a diagnostic aid were calculated, and variable importance was determined to assess each variable's relative influence on the model. In our cohort, EBL diagnosis was negatively associated with tumor site (neck) and not significantly associated with tumor site (jaw). A shorter duration of symptoms was associated with a diagnosis of EBL. Presence of MYC translocation t(8;14), higher EBV fragment size ratio, proportion, entropy, and copies per cell for EBER1, EBER2, and EBNA2 were all associated with a diagnosis of EBL.The combined liquid biopsy diagnostic prediction model had an estimated AUC of 90%, with sensitivity between 85%-90%, specificity between 75% - 80%, and positive and negative predictive values of 85% (Figure 1). MYC translocation t(8;14) was the most important diagnostic variable, followed by EBV entropy (Figure 2). This study demonstrates the feasibility of liquid biopsy as a non-invasive diagnostic aid for EBL in settings without easy access to pathology. To strengthen the application of this technology into clinical practice, further analysis is being conducted for weighting and assigning of scores for each predictor variable. This would assist clinicians in making a precise diagnosis, complementing existing diagnostic modalities for EBL, and reducing the rate of misdiagnosis arising from diagnosis based on clinical suspicion and tissue morphology without immunohistochemistry.

Plasmid DNA extraction by double magnetic beads method and its application

Plasmids are the most commonly used gene carriers in the field of gene synthesis and sequencing. However, the main problems faced by traditional plasmid DNA extraction technology are low extraction throughput and high production cost, so they cannot meet the growing demand. In this study, a double-magnetic-bead method (DMBM) for plasmid extraction was developed based on the principle of plasmid extraction. The effects of the input of magnetic beads, the size of plasmid DNA fragments, and the volume of bacterial on plasmid DNA extraction were explored. In addition, the quality, throughput, and cost of plasmid DNA extraction were also compared between this technique and the commercial plasmid DNA extraction kits. The results showed that the DMBM can meet the needs of extracting plasmid DNA with different cell densities and fragment lengths. Moreover, the sensitivity and quality of plasmid extraction by the DMBM method were both superior to those of the centrifugal adsorption column method. In addition, this technique could be applied on a 96-channel automated nucleic acid extractor, resulting in higher purity of the extracted plasmid DNA, 80% reduction in extraction time, and 57.1% reduction in cost. It also reduces manual operations, achieving high-throughput and low-cost plasmid DNA extraction, thus may facilitate gene synthesis and sequencing.

Phylogenetic inference of pneumococcal transmission from cross-sectional data, a pilot study.

Background: Inference on pneumococcal transmission has mostly relied on longitudinal studies which are costly and resource intensive. Therefore, we conducted a pilot study to test the ability to infer who infected whom from cross-sectional pneumococcal sequences using phylogenetic inference. Methods: Five suspected transmission pairs, for which there was epidemiological evidence of who infected whom, were selected from a household study. For each pair, Streptococcus pneumoniae full genomes were sequenced from nasopharyngeal swabs collected on the same day. The within-host genetic diversity of the pneumococcal population was used to infer the transmission direction and then cross-validated with the direction suggested by the epidemiological records. Results: The pneumococcal genomes clustered into the five households from which the samples were taken. The proportion of concordantly inferred transmission direction generally increased with increasing minimum genome fragment size and single nucleotide polymorphisms. We observed a larger proportion of unique polymorphic sites in the source bacterial population compared to that of the recipient in four of the five pairs, as expected in the case of a transmission bottleneck. The only pair that did not exhibit this effect was also the pair that had consistent discordant transmission direction compared to the epidemiological records suggesting potential misdirection as a result of false-negative sampling. Conclusions: This pilot provided support for further studies to test if the direction of pneumococcal transmission can be reliably inferred from cross-sectional samples if sequenced with sufficient depth and fragment length.

Predicting tumour content of liquid biopsies from cell-free DNA

BackgroundLiquid biopsy is a minimally-invasive method of sampling bodily fluids, capable of revealing evidence of cancer. The distribution of cell-free DNA (cfDNA) fragment lengths has been shown to differ between healthy subjects and cancer patients, whereby the distributional shift correlates with the sample’s tumour content. These fragmentomic data have not yet been utilised to directly quantify the proportion of tumour-derived cfDNA in a liquid biopsy.ResultsWe used statistical learning to predict tumour content from Fourier and wavelet transforms of cfDNA length distributions in samples from 118 cancer patients. The model was validated on an independent dilution series of patient plasma.ConclusionsThis proof of concept suggests that our fragmentomic methodology could be useful for predicting tumour content in liquid biopsies.

A fluorescent sensor based on strand displacement amplification and primer exchange reaction coupling for label-free detection of miRNA

MicroRNAs (miRNAs) are closely associated with human disease occurrence, including cancers, diabetes, inflammation, heart diseases, and viral infections, and their rapid and accurate detection is vital for the diagnosis and treatment of these diseases. Based on one-step reaction of strand displacement amplification (SDA) and primer exchange reaction (PER), a label-free and highly sensitive miRNA-21 detection strategy was developed. In this strategy, the target miRNA-21 binds directly to the hairpin template, triggering the SDA reaction and generating a large number of single strand DNAs as primers for PER amplification. With the help of polymerase, plenty of G-quadruplex fragments of different lengths were accumulated, and the organic dye thioflavin T selectively binds to these G-quadruplex fragments to produce a strong fluorescent signal. There is a wide detection range in this method, miRNA-21 can be detected in the range of 10 fM - 1 nM, the detection limit is low (1.25 fM). This method has good specificity and can effectively distinguish single-base mismatches of miRNA. In addition, the versatility of the method was validated by changing the target recognition site of SDA template.

Functional characterization of the MSP-C6 promoter as a potential tool for mesocarp-preferential expression of transgenes

Modification of lipid composition in the mesocarp tissue of oil palm involves genetic manipulation of multiple genes. More than one mesocarp-preferential promoter is necessary for the expression of individual transgenes in the same plant to obviate transcriptional gene silencing. This study aimed to identify genes that are preferentially expressed in the mesocarp tissue and characterize selected candidate mesocarp-preferential promoters. Ten transcripts that were preferentially expressed in the mesocarp tissue were identified from the analysis of 82 transcriptome datasets of 12 different oil palm tissues. The expression of two candidate genes, MSP-C1 and MSP-C6, was verified to be preferentially expressed in the mesocarp tissues and shown to have a low expression level in non-mesocarp tissues by reverse transcription quantitative real-time PCR (RT-qPCR). MSP-C6 promoter fragments of different lengths were transformed into tomato plants for further characterization. Both unripe and ripe fruits of transgenic tomato plants transformed with a construct harboring the MSP-C6-F1 (2014 bp) promoter were shown to have high beta-glucuronidase (GUS) activities. The findings of this study suggest the potential applications of the MSP-C6 promoter as a molecular tool for genetic engineering of novel traits in fruit crops.

Biogenesis, function, and landscape of tsRNAs in central nervous system diseases

AbstractTransfer RNA‐derived small RNAs (tsRNAs) are fragments that originate from mature or precursor tRNAs and are a subclass of sRNAs. With the development of high‐throughput sequencing techniques, the real feature of tsRNAs has gradually been revealed. tsRNAs are functional fragments of distinct lengths produced by the cleavage of mature or precursor tRNAs by different ribonuclease enzymes. tsRNAs exert extensive functions, including gene silencing, translational regulation, and reverse transcriptional regulation, affecting cell viability and differentiation and participating in pathological processes of various diseases, including central nervous system (CNS) diseases. Emerging sequencing evidence indicates that tsRNAs are expressed differently in various CNS diseases, preliminary suggesting that tsRNAs are involved in the occurrence and progression of neurodegenerative diseases, stroke, glioma, epilepsy, and other CNS diseases. In addition, significant differences expression of extracellular tsRNAs in circulating or cerebrospinal fluid between patients and normal individuals have demonstrated the diagnostic and prognostic value of tsRNAs as biomarkers for liquid biopsy. In this review, we provide a detailed summary of the biogenesis, function, and chemical modification of tsRNAs, focusing on the current status and prospects of research on tsRNAs in neurodegenerative diseases, stroke, glioma, epilepsy, and others.

Molecular detection of Fasciola, Schistosoma and Paramphistomum species from freshwater snails occurring in Gauteng and Free State provinces, South Africa

Trematodiases are diseases caused by snail-borne trematode parasites that infect both animals and humans. Fascioliasis, schistosomiasis and paramphistomosis are some of these diseases and they affect millions of livestock, leading to significant economic losses. The aim of the study was to document freshwater snails occurring in selected study sites in the Free State and Gauteng provinces as well as identify and detect larval trematodes that they harbour. Samples were collected from a total of five study sites within two provinces of South Africa. Morphological features were used to identify snail species and were further confirmed genetically by polymerase chain reaction (PCR), sequencing and phylogenetic analysis. The larval trematodes were also detected by PCR, PCR-Restriction Length Fragment Polymorphism (PCR-RLFP), sequencing and phylogenetic analysis. A total of 887 freshwater snails were collected from Free State (n = 343) and Gauteng (n = 544). Five different genera of snails as well as species in the Succineidae family were documented. The snails in descending order of abundance were identified as: Physa (P.) spp. (51%), Succineidae spp. (20%), Galba (G.) truncatula (12%), Pseudosuccinea (Ps.) columella (10%), Planorbella (Pl.) duryi (6%) and Bulinus (B.) truncatus (1%). Approximately 272 DNA pools were created for genetic identification of snails and detection of trematode parasites. Schistosoma species were not detected from any of the snail species. A total prevalence of 46% was obtained for Fasciola hepatica in the identified snail species across all study sites. Overall, the highest prevalence of F. hepatica was obtained in Physa species (24%), whilst the lowest was observed in B. truncatus snails (1%). Forty three percent (43%) of the snail samples were PCR positive for Paramphistomum DNA. This is the first report of P. mexicana in South Africa. Fasciola hepatica was confirmed from all obtained snail species per study site. This is the first reported detection of F. hepatica in Pl. duryi and P. mexicana snails as well as the first confirmation of natural infection from P. acuta in South Africa.

Determining the Authorship of a Ukrainian-Language Literary Text by Means of Artificial Intelligence from Ultra-Short Excerpts

Purpose. The intelligent search engine Bing can be used as a method and a means of determining the author of a Ukrainian-language test. Bing helps to find information about a text fragment and its author, but the search results may be inaccurate or incomplete. The main purpose of the paper is to study the effectiveness of establishing the authorship of literary texts by state-of-the-art artificial intelligence tools based on ultra-short excerpts. Methodology. Ten Ukrainian authors with a rich body of fiction reflecting various aspects of Ukrainian culture and history were selected, as well as random fragments of 3–7 words each from different works of these authors. An experiment was conducted to determine the authorship of 2,000 fragments. Findings. Using the Python programming language and the skpy package, we developed software that sends questions and receives answers from the Bing bot built into Microsoft Skype. The answers were checked for the name of the author of the phrase and the corresponding title of the work. According to the results, Ivan Franko has the highest percentage of answers where the author's name was mentioned (65%), and Oleksandr Dovzhenko has the lowest result (23%). The answers were analyzed by the length of the fragments. Of course, the longer the length of a text fragment, the greater the likelihood of accurately identifying its authorship. Features of the author's style are manifested in 20–40 % of short fragments. The remaining 60–80% may be commonly used language constructions that the author relayed from the external environment. Originality. In this work, for the first time, the method of checking the authorship of fragments of Ukrainian-language text using the Bing bot with artificial intelligence is presented. A comparative analysis was performed and experiments were given to determine the authorship of short fragments of 3–7 words. It has been established that even quite small fragments of the text have signs characteristic of the original style of the author of artistic works. Practical value. It has been determined to what extent experts in determining the authorship of natural language texts can rely on existing state-of-the-art artificial intelligence tools in combination with an extensive database of texts in the Internet space.

Early gastrointestinal tumour detection using cfDNA fragmentomes based on low-pass whole-genome sequencing (lp-WGS).

e15511 Background: As one of the most concerning world public health issue, cancer accounted for 21% of all deaths. Early cancer detection methods help reduce the chance of dying from cancer. The fragmentation patterns of plasma circulating cell-free DNA (cfDNA) in tumor patients and healthy people are different, which reflects aberrant gene-regulation in cancer patients. Measure cfDNA fragmentomics not only identify the biomarkers to detect cancer early, but also contribute to revealing the biological regulatory mechanism of cancer. In this study, a novel method, i.e. multi-fragmentomics early tumor detection method (METD) was developed, which combined multiple cfDNA fragmentation features and effectively predicted early stage cancer patients. Methods: Adapter sequences were removed from raw data which are then aligned to hg19 reference genome. Duplicated reads, low quality reads and reads aligned to sex chromosomes were removed. Fragment length were normalized through z-score and GC content were regressed out from each bin using GBM (Gradient Boosting Machine) regression tree. Using data from 100 healthy samples, the baseline were calculated. Six fragmentation features including FSD (fragment size distribution) that is a ratio of short/long fragment numbers, EM (end motif) which represent the frequency of 5’end 2-6bp sequence patterns, BPM (break-point motifs) that is the frequency of 5’ end break-point sequences, TFAS (transcription factor accessibility score) that is the rank of coverage at transcription factor binding sites, CFS (co-fragmentation score) which calculate the first principle component of the free-C correlation matrix, GES (gene expression score) that measures the predicted gene expression from cfDNA lp-WGS data were calculated for each sample. Then these 6 fragmentation features were fitted in a penalized logistic regression for cancer prediction. Data of each sample was also downsampled to 0.1x, 0.5x, 1x, 3x and 5x to test the minimum amount of data needed for this prediction model. Results: In training data set, 208 samples from gastrointestinal cancer patients and 100 samples from healthy individuals, our method METD detect tumor patients with a AUC of 0.98. The AUC is 0.95 when the training data were downsampled to 0.1x. This method was then tested in a validation data set containing 32 cancer patients and 32 healthy individuals, which showed a specificity of 0.9 and sensitivity of 0.88. Conclusions: In this study, we develop a new method for early cancer detection integrating different fragmentomics features and demonstrated that lp-WGS data even with 0.1x data can be used to distinguish cancer and healthy groups. Studies with larger cohorts is warranted to verify the performance of this method in future.

Разработка ДНК-маркеров признака устойчивости подсолнечника к расе G заразихи (Orobanche cumana Wallr.)

Broomrape (Orobanche cumana Wallr.) is an obligatory parasite which is able to decrease significantly sunflower yields. The race G is the most spread and virulence broomrape race in the Russian Federation. Cultivation of genetically resistance sunflower varieties and hybrids is the most ecologic and economically efficient method to control this parasite plant. Usage of DNA-markers when selecting the resistant plants increases significantly the effectiveness of a breeding process. To mark the sunflower resistance to broomrape race G, using bioinformative approaches, we developed new DNA-markers: four SCAR (sequence characterized amplified region) and ten SSR (simple sequence repeat). These markers were tested on 20 lines and hybrids of sunflower. Due to the results of this testing, all SSR- and two SCAR-markers were eliminated by steps. SCAR-marker RORS1 was characterized with the presence of an amplified DNA fragment with a length ≈ 168 bps and showed association with a trait of resistance, and SORS1 with a fragment length ≈ 322 bps had a relation with a sus-ceptible phenotype. These markers composed a marker system for a multiplex PCR, which allowed distinguishing resistant and susceptible lines and hybrids, except a line VK678 and F1 hybrids developed using this line as parental one. To eliminate faults of the marker system, seven SCAR-markers analogous to SORS1 were created. Due to estimation result, we selected a marker SORS9 characterized with the presence an amplified DNA fragment with a length ≈ 217 bps in susceptible phenotypes. The new system of markers RORS1/SORS9 for a multiplex PCR was validated on 70 sunflower lines and hybrids. The susceptible lines and hybrids were characterized with amplification of only marker SORS9, resistant lines – only marker RORS1, and resistant hybrids – both markers. The developed marker system allowed distinguishing all susceptible lines and hybrids from the resistant sunflower genotypes.