Molecular Diagnosis Research Articles

Long-read next-generation sequencing for molecular diagnosis of pediatric endocrine disorders.

Recent advances in long-read next-generation sequencing (NGS) have enabled researchers to identify several pathogenic variants overlooked by short-read NGS, array-based comparative genomic hybridization, and other conventional methods. Long-read NGS is particularly useful in the detection of structural variants and repeat expansions. Furthermore, it can be used for mutation screening in difficultto- sequence regions, as well as for DNA-methylation analyses and haplotype phasing. This mini-review introduces the usefulness of long-read NGS in the molecular diagnosis of pediatric endocrine disorders.

Molecular Mechanisms Governing Sight Loss in Inherited Cone Disorders.

Inherited cone disorders (ICDs) are a heterogeneous sub-group of inherited retinal disorders (IRDs), the leading cause of sight loss in children and working-age adults. ICDs result from the dysfunction of the cone photoreceptors in the macula and manifest as the loss of colour vision and reduced visual acuity. Currently, 37 genes are associated with varying forms of ICD; however, almost half of all patients receive no molecular diagnosis. This review will discuss the known ICD genes, their molecular function, and the diseases they cause, with a focus on the most common forms of ICDs, including achromatopsia, progressive cone dystrophies (CODs), and cone-rod dystrophies (CORDs). It will discuss the gene-specific therapies that have emerged in recent years in order to treat patients with some of the more common ICDs.

Plasma extracellular vesicle tau and TDP-43 as diagnostic biomarkers in FTD and ALS

Minimally invasive biomarkers are urgently needed to detect molecular pathology in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Here, we show that plasma extracellular vesicles (EVs) contain quantifiable amounts of TDP-43 and full-length tau, which allow the quantification of 3-repeat (3R) and 4-repeat (4R) tau isoforms. Plasma EV TDP-43 levels and EV 3R/4R tau ratios were determined in a cohort of 704 patients, including 37 genetically and 31 neuropathologically proven cases. Diagnostic groups comprised patients with TDP-43 proteinopathy ALS, 4R tauopathy progressive supranuclear palsy, behavior variant FTD (bvFTD) as a group with either tau or TDP-43 pathology, and healthy controls. EV tau ratios were low in progressive supranuclear palsy and high in bvFTD with tau pathology. EV TDP-43 levels were high in ALS and in bvFTD with TDP-43 pathology. Both markers discriminated between the diagnostic groups with area under the curve values >0.9, and between TDP-43 and tau pathology in bvFTD. Both markers strongly correlated with neurodegeneration, and clinical and neuropsychological markers of disease severity. Findings were replicated in an independent validation cohort of 292 patients including 34 genetically confirmed cases. Taken together, the combination of EV TDP-43 levels and EV 3R/4R tau ratios may aid the molecular diagnosis of FTD, FTD spectrum disorders and ALS, providing a potential biomarker to monitor disease progression and target engagement in clinical trials.

Precision Basecalling of Single DNA Nucleotide from Overlapped Transmission Readouts with Machine Learning Aided Solid-State Nanogap.

DNA sequencing with the quantum tunneling technique heralds a paradigm shift in genetic analysis, promising rapid and accurate identification for diverging applications ranging from personalized medicine to security issues. However, the widespread distribution of molecular conductance, conduction orbital alignment for resonant transport, and decoding crisscrossing conductance signals of isomorphic nucleotides have been persistent experimental hurdles for swift and precise identification. Herein, we have reported a machine learning (ML)-driven quantum tunneling study with solid-state model nanogap to determine nucleotides at single-base resolution. The optimized ML basecaller has demonstrated a high predictive basecalling accuracy of all four nucleotides from seven distinct data pools, each containing complex transmission readouts of their different dynamic conformations. ML classification of quaternary, ternary, and binary nucleotide combinations is also performed with high precision, sensitivity, and F1 score. ML explainability unravels the evidence of how extracted normalized features within overlapped nucleotide signals contribute to classification improvement. Moreover, electronic fingerprints, conductance sensitivity, and current readout analysis of nucleotides have promised practical applicability with significant sensitivity and distinguishability. Through this ML approach, our study pushes the boundaries of quantum sequencing by highlighting the effectiveness of single nucleotide basecalling with promising implications for advancing genomics and molecular diagnostics.

Leveraging the fundamentals of heat transfer and fluid mechanics in microscale geometries for automated next-generation sequencing library preparation

Next-generation sequencing (NGS) is emerging as a powerful tool for molecular diagnostics but remains limited by cumbersome and inefficient sample preparation. We present an innovative automated NGS library preparation system with a simplified mechanical design that exploits both macro- and microfluidic properties for optimizing heat transfer, reaction kinetics, mass transfer, fluid mechanics, adsorption–desorption rates, and molecular thermodynamics. Our approach introduces a unique two-cannula cylindrical capillary system connected to a programmable syringe pump and a Peltier heating element able to execute all steps with high efficiency. Automatic reagent movement, mixing, and magnetic bead-based washing with capillary-based thermal cycling (capillary-PCR) are completely integrated into a single platform. The manual 3-h library preparation process is reduced to less than 15 min of hands-on time via optimally pre-plated reagent plates, followed by less than 6 h of instrument run time during which no user interaction is required. We applied this method to two library preparation assays with different DNA fragmentation requirements (mechanical vs. enzymatic fragmentation), sufficiently limiting consumable use to one cartridge and one 384 well-plate per run. Our platform successfully prepared eight libraries in parallel, generating sequencing data for both human and Escherichia coli DNA libraries with negligible coverage bias compared to positive controls. All sequencing data from our libraries attained Phred (Q) scores > 30, mapping to reference genomes at 99% confidence. The method achieved final library concentrations and size distributions comparable with the conventional manual approach, demonstrating compatibility with downstream sequencing and subsequent data analysis. Our engineering design offers repeatability and consistency in the quality of sequence-able libraries, asserting the importance of mechanical design considerations that employ and optimize fundamental fluid mechanics and heat transfer properties. Furthermore in this work, we provide unique insights into the mechanisms of sample loss within NGS library preparation assays compared with automated adaptations and pinpoint areas in which the principles of thermodynamics, fluid mechanics, and heat transfer can improve future mechanical design iterations.

Comparison of transbronchial biopsy techniques using needle and forceps biopsies in lung cancer for molecular diagnostics: a prospective, randomized crossover trial.

In lung cancer, molecular testing and next-generation sequencing (NGS) are needed to identify therapeutic targets and are increasingly being used in earlier stages of the disease. Despite its longstanding use, it remains unclear whether transbronchial needle aspiration (TBNA) of peripheral lung lesions provides as adequate material for genetic testing as transbronchial forceps biopsies (TBFBs). In this study, we aim to analyze the use of TBNA using median viable cell area (MVCA) as a surrogate parameter to analyze sample quality. This prospective single-center study analyzed biopsy specimens or aspirates of patients who underwent bronchoscopy with transbronchial biopsy. Patients underwent bronchoscopy with TBFB and TBNA for suspected lung cancer in peripheral lung lesions. Patients were randomized 1:1 to receive either TBFB or TBNA as the first biopsy technique and then switched to the other. After routine workup, sample slides were digitally scanned, and MVCA was calculated by a pathologist blinded to the biopsy technique used. The primary endpoint was MVCA of TBNA versus TBFB. Secondary endpoints were complications categorized as bleeding, pneumothorax, and other. Between August 2021 and April 2022, 15 patients were included in the per-protocol analysis. Six patients were included in cohort 1 and nine patients in cohort 2. A malignant diagnosis was confirmed in 11/15 (73.3%) cases, of which nine were primary lung malignancies. Overall, MVCA in samples obtained by TBFB was significantly larger than TBNA samples {TBFB-MVCA 9.80 mm2 [interquartile range (IQR), 2.70-10.39 mm2] vs. TBNA-MVCA 2.70 mm2 (IQR, 0.14-8.21 mm2), P=0.008}. Despite this difference, molecular testing was feasible in both TBNA and TBFB samples. No major complications were observed. Despite a significantly smaller MVCA provided by TBNA, samples were still considered feasible for NGS, indicating that TBNA represents an alternative method to obtain sufficient tumor tissue in peripheral nodules as part of the diagnosis of suspected lung cancer.

Genetic etiology study in a large cohort with congenital insensitivity to pain with anhidrosis.

Pathogenic variations in the NTRK1 can cause congenital insensitivity to pain with anhidrosis (CIPA), a rare autosomal recessive inherited neuropathy. The precise diagnosis of CIPA relies on the identification of pathogenic genotypes. Therefore, it is essential to expand the NTRK1 variation spectrum and improve molecular diagnosis methods. In this study, 74 probands with typical manifestations of CIPA but unknown genotypes were recruited. A comprehensive molecular genetic analysis was performed to identify variations in the NTRK1, using techniques including Sanger and next-generation sequencing, bioinformatic analysis, quantitative polymerase chain reaction (qPCR), gap-PCR, short tandem repeat (STR) genotyping, and reverse-transcription PCR. In addition, functional assays were conducted to determine the pathogenicity of variants of uncertain significance (VUS) and further characterized changes in glycosylation and phosphorylation of 14 overexpressed mutant vectors with variants at different domains in the TrkA protein, which is encoded by NTRK1. A total of 48 variations in the NTRK1 were identified, including 22 novel ones. When combined with data from another 53 CIPA patients examined in our previous work, this study establishes the largest genotypic and phenotypic spectra of CIPA worldwide, including 127 CIPA families. Moreover, functional studies indicated that the pathogenicity of VUS mainly affected insufficient glycosylation in the extracellular domain and abnormal phosphorylation in the intracellular domain. This study not only provides important evidence for precise diagnosis of CIPA but also further enriches our understanding of the pathogenesis of this disease.

Mutations in the U4 snRNA gene RNU4-2 cause one of the most prevalent monogenic neurodevelopmental disorders.

Most people with intellectual disability (ID) do not receive a molecular diagnosis following genetic testing. To identify new etiologies of ID, we performed a genetic association analysis comparing the burden of rare variants in 41,132 noncoding genes between 5,529 unrelated cases and 46,401 unrelated controls. RNU4-2, which encodes U4 small nuclear RNA, a critical component of the spliceosome, was the most strongly associated gene. We implicated de novo variants among 47 cases in two regions of RNU4-2 in the etiology of a syndrome characterized by ID, microcephaly, short stature, hypotonia, seizures and motor delay. We replicated this finding in three collections, bringing the number of unrelated cases to 73. Analysis of national genomic diagnostic data showed RNU4-2 to be a more common etiological gene for neurodevelopmental abnormality than any previously reported autosomal gene. Our findings add to the growing evidence of spliceosome dysfunction in the etiologies of neurological disorders.

Basic knowledge for counseling patients undergoing risk-reducing salpingo-oophorectomy.

Significant progress has been made in the molecular diagnosis of cancer. It provides personalized medicine, including cancer diagnosis, prognosis, targeted therapy, and risk detection. These advances allow physicians to identify patients at risk for cancer before it develops and offer them an opportunity to prevent its development. Mutations in breast cancer susceptibility genes 1 and 2 (BRCA1 and 2) are one of the most well-known cancer-related gene mutations since actor Angelina Jolie shared her experience with genetic mutations and risk-reducing surgery in the media. In Korea, tests for germline BRCA1/2 mutations have been covered by insurance since May 2012 and the number of carriers of BRCA1/2 mutations has continued to increase over the past decade. Most carriers of BRCA1/2 mutations consider risk-reducing salpingo-oophorectomy (RRSO) resulting in early menopause and want to know the lifetime risks and benefits of RRSO. However, despite the increasing number of carriers of BRCA1/2 mutations, the counseling and management of patients requiring RRSO varies among physicians. This article provides basic knowledge on RRSO to help physicians comprehensively assess its risks and benefits and manage at-risk women.

Familial dominant drusen (Malattia leventinese / Doyne honeycomb retinal dystrophy)

Familial dominant drusen is an autosomal dominant, progressive retinal disorder characterized by central retinal drusen which often coalesce to form a honeycomb pattern. It is usually bilateral and occurs in early adulthood. Early diagnosis and follow up is essential as occurrence of choroidal neovascularisation is a possibility. Currently there is no effective treatment for this condition. Genetic counselling and molecular diagnosis are recommended.

Microscopic and Molecular Diagnosis of Cryptosporidium spp. in Human in Babylon Province, Iraq

Background: Considering the importance of Cryptosporidium spp. to public health and the country's economic situation due to the threat of an outbreak and economic losses. Objectives: this study aimed to detect Cryptosporidium spp. in human in Babylon province using traditional and molecular techniques. Methods: this study was conducted in Babylon province from September, 2023 to March, 2024.a total of 100 human stool samples were examined microscopically for detection of Cryptosporidium spp. from both diarrheal and non-diarrheal patients attend hospitals and public health centers laboratories. Results: by using microscopic examination. The rate of infection with Cryptosporidium spp. was (25/100), 25%. According to sex, the highest infection rate in humans was in males (17/59),28.81% compared to females (8/41) ,19,51%. was recorded in the rate of infection between age groups, the highest rate (13/28), 46.42% observed in < 5years of human. Rural area revealed the highest rate of infection than urban area in human (16/44),36.63%. In molecular diagnosis, DNA extraction was performed for 50 stool samples human 28% (14/50) C hominis 10% (5/50) C parvum 18% (9/50) by nested PCR, in order to investigate the genotypes of Cryptosporidium spp. from human in Babylon, five Cryptosporidium spp. isolates. were genetically characterized by SSU-rDNA gene sequencing. The results showed C parvum (1/5) C hominis (4/5). Conclusion: these findings suggested that infection of humans by zoonotic genotypes were the most common genotypes detected in all human samples in Babylon province, to enhance the effectiveness of the One Health approach in preventing Cryptosporidium spp. infection, it is crucial to have a deeper understanding of the environmental, epidemiological, and etiological aspects linked to Cryptosporidium infection. This knowledge will aid in the development of more effective risk management strategies. The future One Health plan seeks to incorporate diverse and interdisciplinary expertise.

Cross-Reactivity of Ragweed Pollen Calcium-Binding Proteins and IgE Sensitization in a Ragweed-Allergic Population from Western Romania.

Ragweed pollen allergy is the most common seasonal allergy in western Romania. Prolonged exposure to ragweed pollen may induce sensitization to pan-allergens such as calcium-binding proteins (polcalcins) and progression to more severe symptoms. We aimed to detect IgE sensitization to recombinant Amb a 9 and Amb a 10 in a Romanian population, to assess their potential clinical relevance and cross-reactivity, as well as to investigate the relation with clinical symptoms. rAmb a 9 and rAmb a 10 produced in Escherichia coli were used to detect specific IgE in sera from 87 clinically characterized ragweed-allergic patients in ELISA, for basophil activation experiments and rabbit immunization. Rabbit rAmb a 9- and rAmb a 10-specific sera were used to detect possible cross-reactivity with rArt v 5 and reactivity towards ragweed and mugwort pollen extracts. The results showed an IgE reactivity of 25% to rAmb a 9 and 35% to rAmb a 10. rAmb a 10 induced basophil degranulation in three out of four patients tested. Moreover, polcalcin-negative patients reported significantly more skin symptoms, whereas polcalcin-positive patients tended to report more respiratory symptoms. Furthermore, both rabbit antisera showed low reactivity towards extracts and showed high reactivity to rArt v 5, suggesting strong cross-reactivity. Our study indicated that recombinant ragweed polcalcins might be considered for molecular diagnosis.

Hexanucleotide repeat expansion in SCA36 reduces the expression of genes involved in ribosome biosynthesis and protein translation.

Hereditary spinocerebellar ataxia (SCA) is a group of clinically and genetically heterogeneous inherited disorders characterized by slowly progressive cerebellar ataxia. We ascertained a Japanese pedigree with autosomal dominant SCA comprising four family members, including two patients. We identified a GGCCTG repeat expansion of intron 1 in the NOP56 gene by Southern blotting, resulting in a molecular diagnosis of SCA36. RNA sequencing using peripheral blood revealed that the expression of genes involved in ribosomal organization and translation was decreased in patients carrying the GGCCTG repeat expansion. Genes involved in pathways associated with ribosomal organization and translation were enriched and differentially expressed in the patients. We propose a novel hypothesis that the GGCCTG repeat expansion contributes to the pathogenesis of SCA36 by causing a global disruption of translation resulting from ribosomal dysfunction.

Enhancing personalized medicine through molecular diagnostics: Implications for nursing care

The advent of molecular diagnostics, exemplified by technologies such as Polymerase Chain Reaction (PCR) and gene sequencing, represents a pivotal shift towards personalized medicine, fundamentally altering the landscape of healthcare delivery and nursing care. This paper delves into the transformative potential of genetic screening and risk assessment, disease typing and classification, and predictive analysis of treatment responses, highlighting the critical role of molecular diagnostics in facilitating a more nuanced understanding of individual health profiles and tailoring treatment accordingly. The integration of genetic data into treatment planning enables healthcare practitioners to optimize therapeutic strategies, significantly improving patient outcomes. However, this advancement is not without challenges. The ethical considerations surrounding data privacy, the complexity of genetic information, and issues of cost and accessibility are scrutinized, underscoring the need for robust ethical guidelines, continuous professional education, and policy interventions to ensure equitable access to these technologies. Through a comprehensive review, this paper illustrates the intricate interplay between molecular diagnostics and personalized nursing care, advocating for an interdisciplinary approach to harness the full potential of these technological advancements in improving patient care.

Visual and molecular serologic diagnosis of sarcocystosis in cattle

The purpose of the research is to provide a comparative assessment of efficacy of different diagnostic methods for sarcocystosis in cattle.Materials and methods. Seventy-eight bovine carcasses were examined using methods and regulations of veterinary and sanitary examination. Muscles of the esophagus and other parts of the carcass as well as the spleen, lungs, the liver, and kidneys were examined. The compressor research method was used. A total of 156 compressoria from 78 bovine carcasses were analyzed for tissue sarcocystosis. For life-time diagnostics of bovine sarcocystosis, a molecular serologic method (ELISA) was used that was developed based on antibody detection principles.Results and discussion. Two diagnostic methods, visual inspection and compressor microscopy, identified 13 out of 78 carcasses with Sarcocystis species, which was 16.6%. The number of sarcocystosis animals increased by another 23 cases when studying blood sera from the cattle using ELISA. Thus, we found 36 animals suffering from sarcocystosis out of 78 examined, which was 46%, with tests based on different principles.

Molecular and serological diagnosis of multiple bacterial zoonoses in febrile outpatients in Garissa County, north-eastern Kenya

Bacterial zoonoses are diseases caused by bacterial pathogens that can be naturally transmitted between humans and vertebrate animals. They are important causes of non-malarial fevers in Kenya, yet their epidemiology remains unclear. We investigated brucellosis, Q-fever and leptospirosis in the venous blood of 216 malaria-negative febrile patients recruited in two health centres (98 from Ijara and 118 from Sangailu health centres) in Garissa County in north-eastern Kenya. We determined exposure to the three zoonoses using serological (Rose Bengal test for Brucella spp., ELISA for C. burnetti and microscopic agglutination test for Leptospira spp.) and real-time PCR testing and identified risk factors for exposure. We also used non-targeted metagenomic sequencing on nine selected patients to assess the presence of other possible bacterial causes of non-malarial fevers. Considerable PCR positivity was found for Brucella (19.4%, 95% confidence intervals [CI] 14.2–25.5) and Leptospira spp. (1.7%, 95% CI 0.4–4.9), and high endpoint titres were observed against leptospiral serovar Grippotyphosa from the serological testing. Patients aged 5–17 years old had 4.02 (95% CI 1.18–13.70, p-value = 0.03) and 2.42 (95% CI 1.09–5.34, p-value = 0.03) times higher odds of infection with Brucella spp. and Coxiella burnetii than those of ages 35–80. Additionally, patients who sourced water from dams/springs, and other sources (protected wells, boreholes, bottled water, and water pans) had 2.39 (95% CI 1.22–4.68, p-value = 0.01) and 2.24 (1.15–4.35, p-value = 0.02) times higher odds of exposure to C. burnetii than those who used unprotected wells. Streptococcus and Moraxella spp. were determined using metagenomic sequencing. Brucellosis, leptospirosis, Streptococcus and Moraxella infections are potentially important causes of non-malarial fevers in Garissa. This knowledge can guide routine diagnosis, thus helping lower the disease burden and ensure better health outcomes, especially in younger populations.

A Rapid and Robust DNA Extraction Method for PCR-Based Diagnosis of V. cholerae

Cholera, caused by _V. cholerae_, needs rapid diagnosis because of its threat for rapid spread. Recent molecular diagnosis by PCR assay is more advantageous than the conventional methods. The bottleneck in PCR diagnosis lies in the delay in template DNA extraction of _V. cholerae_, which is the basic requirement. This study describes a simple, less expensive, and rapid template DNA extraction method to lessen the total time for PCR diagnosis of _V. cholerae._ To obtain template DNA, our method involves boiling of _V. cholerae_ suspension in distilled water (takes 18-24 hours) instead of boiling the suspension in broth medium, which is a lengthy process (takes 72 hours). The validation of our template DNA was conducted using 40 _V. cholerae_ O1 strains that were confirmed previously, and its usefulness was checked on 20 clinical strains of _V. cholerae_ O1 isolated from acute diarrhea patients; results were compared with those of conventional template DNA. The analysis of our template DNA in simplex and quadruplex PCR assays revealed the presence of _ctxA_, _tcpA _(El Tor), _rfb _(O1), _ToxR_, _ctxB_, _zot_, _ace,rst _, and _OmpW _genes in _V. cholerae _O1. The comparison of the results of PCR assays using the template DNA from both sources showed equal results and matched correctly. The sensitivity of our template DNA was 1.5x103 CFU per assay. Our template DNA extraction method is simple, less expensive, and rapid, and it can be employed for early diagnosis of _V. cholerae_ during outbreaks, in research laboratories, and in hospital setups where infrastructures are available.

Identification of key genes and biological pathways associated with vascular aging in diabetes based on bioinformatics and machine learning.

Vascular aging exacerbates diabetes-associated vascular damage, a major cause of microvascular and macrovascular complications. This study aimed to elucidate key genes and pathways underlying vascular aging in diabetes using integrated bioinformatics and machine learning approaches. Gene expression datasets related to vascular smooth muscle cell (VSMC) senescence and diabetic vascular aging were analyzed. Differential expression analysis identified 428 genes associated with VSMC senescence. Functional enrichment revealed their involvement in cellular senescence, ECM-receptor interaction, PI3K-Akt and AGE-RAGE signaling pathways. Further analysis of diabetic vascular aging datasets revealed 52 differentially expressed genes, enriched in AMPK signaling, AGE-RAGE signaling, cellular senescence, and VEGF signaling pathways. Machine learning algorithms, including LASSO regression and SVM-RFE, pinpointed six key genes: TFB1M, FOXRED2, LY75, DALRD3, PI4K2B, and NDOR1. Immune cell infiltration analysis demonstrated correlations between diabetic vascular aging, the identified key genes, and infiltration levels of plasma cells, M1 macrophages, CD8+ T cells, eosinophils, and regulatory T cells. In conclusion, this study identified six pivotal genes (TFB1M, FOXRED2, LY75, DALRD3, PI4K2B, and NDOR1) closely associated with diabetic vascular aging through integrative bioinformatics and machine learning approaches. These genes are linked to alterations in the immune microenvironment during diabetic vascular aging. This study provides a reference and basis for molecular mechanism research, biomarker mining, and diagnosis and treatment evaluation of diabetes-related vascular aging.

Molecular diagnosis of hen eggs microbiota.

The study was conducted in the Kingdom of Saudi Arabia from 2020 and 2022. The identification, characterization, and evaluation of microbes found in hen eggs was done and it was found very important to prevent contamination caused by various harmful pathogenic microbes. It was found that contaminated eggs harbor various harmful microbes which affect health due to multiple infectious diseases. Hen eggs contain a wide variety of microbes, and several distinct approaches were utilized as well as available for achieving detailed pathogenic information. The information obtained is highly essential for people who consume eggs as a food product. It is of the utmost importance to protect people from getting sick due to the consumption of contaminated eggs or eggs from chickens that have been infected by various harmful pathogens. During the experiment, we found that eggs were contaminated directly or the chicken that laid the egg was contaminated. Using molecular genetic analysis, it is possible to detect pathogenic and non-pathogenic contaminations in eggs. During present studies, the cutting-edge molecular techniques of 16S rRNA gene sequencing technology were used to carry out the objective of performing a molecular identification of the microbial communities infecting eggs. The present research is aimed at determining whether the microbial communities in hen eggs are harmful to humans. The results further indicated most bacteria have the potential to cause illness in humans including Escherichia fergusonii, Salmonella enterica, Pseudocitrobacter faecalis, Yakenella regensburgei, and Erwinia pyrifoliae. Further, research suggested that eggs need to be properly cooked and thoroughly washed to eliminate the possibility of consuming infected eggs.

Sulfur incorporation into nucleic acids accelerates enzymatic activity

DNAzymes play a crucial role in biosensors for signal detection, but specific structures are required for diagnostic applications, complicating their design. This study reports a novel approach to the development of DNAzymes by incorporating sulfur atoms into nucleic acids via phosphorothioate (PS) bonds. Unlike traditional DNAzymes that rely on specific structures such as G-quadruplexes, this approach leads to high enzymatic activity without structural constraints. Computational analysis reveals that the change in the electron density of the nucleobases due to PS modification enhances interactions within the DNAzyme-H2O2-hemin complex, accelerating the rate-determining step and improving enzymatic activity. Systematic guidelines for the development of non-sequence constrained DNAzymes are provided by investigating the effect of the number of PS modifications, the length of the DNA, and various nucleobase combinations. α-thio-dNTP, a monomer containing PS, exhibits no observable enzymatic activity, but enzymatic activity is recorded for single-stranded DNA (ssDNA) containing PS. However, when the ssDNA is transformed into double-stranded DNA (dsDNA), the bases that react with hemin are blocked by hydrogen bonding, reducing enzymatic activity. An enzymogenic signaling system that differentiates between ssDNA and dsDNA is subsequently developed for sequence-specific colorimetric detection, demonstrating significant promise for overcoming the limitations of conventional DNAzymes in molecular diagnosis.