Search Results (493)

Bitter gourd (Momordica charantia L.) is an important vegetable and medicinal crop in tropical/subtropical regions, but suffers severe yield losses (even total failure) from Fusarium wilt caused by Fusarium oxysporum f. sp. momordicae (Fom). There is no specific detection system available to detect this pathogen, and the methods used for other pathogens exhibit cross-reactivity and require specialized equipment. Therefore, this study developed a loop-mediated isothermal amplification (LAMP) assay for early Fom diagnosis. Initially, five sets of LAMP primers targeting the conserved regions of Fom, located within the region amplified by the FOMM-SPF/SPR PCR primers, were tested for specificity and sensitivity. In this experiment, FoM-1-2 showed optimal specificity, identifying 44 Fom strains without cross-reactivity with 10 other non-Fom species after a 60 min incubation at 64 °C. A visual readout based on a fluorescent dye (green for positive, pale orange for negative) eliminated the need for gel electrophoresis and specialized instruments. The LAMP assay was 100-fold more sensitive than conventional PCR (detection limit: 5.6 pg/μL vs. 560 pg/μL). In inoculated seedlings, LAMP detected Fom in basal stems at four days post-inoculation and top leaves at six days, whereas conventional PCR yielded faint bands in the basal stem after eight days. Moreover, LAMP enabled non-destructive detection. Thus, the present study developed a rapid, specific, and sensitive visual LAMP assay, supporting early diagnosis of bitter gourd Fusarium wilt. Full article

Bst DNA polymerase is a biotechnologically modified thermostable enzyme from the thermophilic Gram-positive bacterium Geobacillus stearothermophilus. The unique structure of Bst DNA polymerase determines its thermal stability, ability to replace a DNA strand and specificity. The high specificity of Bst DNA polymerase ensures the efficiency, sensitivity, and high rate of loop-mediated isothermal amplification (LAMP), which is widely used in vitro biotechnology. The review reveals the structural and functional features of the enzyme, its application in LAMP and methods of improvement of thermal stability (including directed evolution, site-directed mutagenesis, fusion constructs, and chemical modifications). The terminal transferase activity and ab initio synthesis are discussed regarding problems of Bst DNA polymerase and the ways to eliminate them. The questions of introducing modified nucleotides and primers to expand the diagnostic capabilities of LAMP are also discussed. Modern advances in Bst DNA polymerase engineering pave the way for the creation of reliable, thermostable, and highly specific test systems suitable for widespread diagnostic applications. Full article

Pythiosis is an emerging infectious disease caused by the oomycete Pythium insidiosum, affecting humans and animals primarily in subtropical and tropical regions. The pathogen is commonly found in swampy environments, and exposure can lead to diverse clinical manifestations. In humans, ocular and vascular infections predominate, whereas in animals, cutaneous/subcutaneous or gastrointestinal disease is more common. Medical therapy is frequently ineffective, and many patients require extensive surgical intervention. Advanced cases may progress to fatal outcomes. Therefore, early and accurate detection is critical for improving clinical management. This study evaluated a colorimetric loop-mediated isothermal amplification (c-LAMP) assay compared with an established multiplex PCR (m-PCR) assay for the detection of P. insidiosum in clinical specimens from animals with and without pythiosis. When tested on 47 frozen tissue samples, c-LAMP demonstrated superior diagnostic performance, with markedly greater sensitivity (83.9% vs. 41.9%), higher accuracy (78.7% vs. 61.7%), and a shorter turnaround time (65 vs. 180 min). However, c-LAMP yielded five false-positive results, likely due to nonspecific amplification or contamination. Improved sample-handling practices increased the specificity from 68.8% to 93.8%. In contrast, m-PCR showed perfect specificity (100.0%) but substantially lower sensitivity, resulting in a high false-negative rate. In conclusion, these preliminary findings suggest that c-LAMP is a promising rapid screening tool for suspected pythiosis, particularly in resource-limited settings. Nevertheless, confirmatory testing remains necessary for positive or equivocal c-LAMP results. Full article

Riemerella anatipestifer (RA) is the primary causative agent of infectious serositis in ducks, causing significant economic losses. In this study, a rapid and visual loop-mediated isothermal amplification (LAMP) assay targeting the conserved region of the ompA gene was developed. Specific primers and a FAM-labeled probe were designed, and amplification products were visualized using phenol red-based colorimetric detection and a lateral flow dipstick (LFD) system. Among the five candidate primer sets, primer set 2 was selected because it showed the highest amplification efficiency and specificity, with no cross-reactivity detected against 12 common waterfowl pathogens. Under optimal conditions, the phenol red-based LAMP assay yielded visible results after incubation at 65 °C for 30 min, while the LAMP-LFD assay required an additional 3~5 min probe hybridization step, with detection limits of 7.76 × 10² copies/μL for the phenol red-based method and 7.76 × 10⁰ copies/μL for the LAMP-LFD method. Thirty clinical samples suspected of RA infection were analyzed using conventional PCR and the developed visual LAMP assays. The positive detection rates obtained with the LAMP-LFD and phenol red-based LAMP methods were 63.3% and 60%, respectively, showing high concordance with conventional PCR (56.7%). In conclusion, the LAMP assay integrating phenol red visualization and lateral flow dipstick detection is rapid, sensitive, and easy to perform, and both detection formats show potential for point-of-care or on-site applications, and can be used for the early diagnosis and detection of RA. Full article

Loop-mediated isothermal amplification (LAMP) is a widely used nucleic acid detection method, but its application is often limited by the suboptimal performance of wild-type Bacillus stearothermophilus (Bst) DNA polymerase. This study employed a combined deep learning and semi-rational design strategy to engineer Bst DNA polymerase. High-throughput screening identified the A0A150MFP3 sequence and the L105M mutation, which increased enzymatic activity by 32.92%. Fusion with the CL7 protein generated a CL7-Bst mutant with enhanced thermal stability and tolerance to common inhibitors, including 7% (v/v) ethanol, 0.18‰ (w/v) SDS, 80 mmol/L NaCl, and 0.8 mmol/L EDTA. Systematic optimization of the LAMP reaction system determined the optimal pH (9.0), enzyme concentration (0.20 U/μL), and temperature (64 °C). When applied to Escherichia coli O157:H7 detection, the CL7-Bst mutant achieved Tt values of 15.13 and 12.78 for crude and purified DNA, respectively, with a limit of detection of 1 × 10³ CFU/mL. In summary, integrating deep learning with semi-rational design and fusion protein engineering yielded a high-performance DNA polymerase that facilitates rapid, sensitive, and field-deployable LAMP-based pathogen detection. Full article

Microbial contamination in aquatic environments poses severe threats to aquaculture sustainability, ecological balance and public health. Traditional culture-based detection methods, while standardized, are time-consuming and labor-intensive, often failing to meet the urgent need for rapid on-site monitoring required to prevent disease outbreaks and manage water quality effectively. By integrating latest research advances (2020–2025), this study reviews advances in rapid detection technologies for aquatic microorganisms, including the evolution of nucleic acid amplification strategies, with a focused comparison of the analytical sensitivity and field deployability of quantitative polymerase chain reaction (qPCR) and mainstream isothermal amplification techniques (loop-mediated isothermal amplification, LAMP; recombinase polymerase amplification, RPA). Furthermore, this study reports on the emergence of Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-associated protein (Cas) systems as next-generation diagnostic tools, highlighting their integration with microfluidic Lab-on-a-Chip (LOC) platforms to achieve attomolar sensitivity. We also consider the application of portable nanopore sequencing for real-time pathogen identification and the growing role of Artificial Intelligence (AI) in analyzing complex diagnostic datasets. Advanced molecular methods have achieved significant reductions in time consumption—from days to less than one hour—while challenges regarding sample preparation and environmental matrix inhibition remain. The future of aquatic monitoring lies in integrated, automated systems that combine the specificity of CRISPR-Cas diagnostics with the connectivity of IoT-enabled biosensors. Comparative analysis indicates that isothermal amplification methods (LAMP, RPA) coupled with CRISPR-Cas systems offer the optimal balance of sensitivity, speed, and field deployability for point-of-care aquaculture diagnostics, while qPCR/dPCR remain indispensable for quantitative regulatory applications. We propose a structured technology selection framework to guide researchers and practitioners in choosing appropriate detection modalities based on specific sensitivity, cost, throughput, and deployment requirements. Full article

Background/Objectives: With the acceleration of global industrialization and continuous population growth, the world is increasingly confronted with the dual challenges of food insecurity and cultivated land contamination. The screening and breeding of rice varieties with superior agronomic traits and low heavy metal accumulation have therefore become important strategies for ensuring food safety and sustainable agricultural production. Methods: In this study, rice varieties carrying the Gn1a-i gene and exhibiting specific cadmium (Cd) accumulation characteristics were screened using a combination of molecular marker detection and cadmium accumulation evaluation. Specific loop-mediated isothermal amplification (LAMP) primers targeting the Gn1a-i gene were designed and combined with a lateral flow dipstick (LFD) assay to enable rapid genetic screening of rice varieties. A six-day hydroponic experiment under cadmium stress was conducted across three temperature ranges (15–20 °C, 22–27 °C, and 30–35 °C), and cadmium accumulation in different plant organs (roots, stem sheath, and leaves) was analyzed. Results: Seven varieties carrying the Gn1a-i gene, including Xiangwanxian 12, were identified among ten tested rice varieties. Xiangwanxian 12 was subsequently selected for further evaluation, with the high-cadmium-accumulating variety Yuzhenxiang used as a control. At 144 h, the total Cd content in the measured organs of Xiangwanxian 12 was 9.6%, 4.0%, and 23.2% lower than that of Yuzhenxiang under low, medium, and high temperatures, respectively (one-tailed t-test, p < 0.01 for all three temperatures). Conclusions: The integration of LAMP-based genotyping and physiological evaluation provides a novel and reliable strategy for identifying low-Cd rice germplasm. Xiangwanxian 12, which carries the Gn1a-i allele and exhibits consistently lower Cd accumulation than Yuzhenxiang, suggests potential as a candidate for breeding high-yield, low-Cd rice cultivars. Full article

Wheat, soybean, and peanut are recognized as major food allergens, with their prevalence rising globally, necessitating rapid and reliable detection methods. A new detection approach was developed in this research, which integrates Ladder-shape Melting Temperature Isothermal Amplification (LMTIA) with Proofreading Enzyme-Mediated Probe Cleavage (Proofman) technology to enable the concurrent identification of wheat, soybean, and peanut allergens. Compared with the loop-mediated isothermal amplification (LAMP) method under the experimental conditions set in this study, this approach can reduce the false-positive results associated with LAMP, and it does not rely on sophisticated instrumentation required by technologies like mass spectrometry. The GAG56D (wheat), Ara h 2.01 (peanut), and Lectin (soybean) genes were selected as target genes for the three allergens. Specific primers and probes were designed according to these target genes, and the reaction system was optimized. A systematic evaluation of the triplex Proofman-LMTIA method was then conducted regarding its specificity, sensitivity, limit of detection, and repeatability. Finally, the method’s practical applicability was validated using commercial products. The optimized system achieved simultaneous detection within 40 min at 61 °C, showing no cross-reactivity with common foods. The method demonstrated good sensitivity, with a sensitivity of 5 pg/μL for genomic DNA and a detection limit of 5% (w/w) in a powder matrix, along with excellent repeatability. In practical sample testing, the results were fully consistent with product label declarations, accurately identifying single and multiple allergen contaminations. The Proofman-LMTIA detection method, with its rapid, simple, sensitive, and specific characteristics, demonstrates significant potential for applications in food safety supervision. Full article

The development of high-throughput, sensitive and portable strategies for detecting foodborne pathogens is urgently needed in food safety, especially during an outbreak. Herein, an ultrasensitive suspension array was constructed by designing photonic crystal microsphere (PCM)-assisted loop-mediated isothermal amplification (LAMP) for Staphylococcus aureus detection. The PCM-LAMP suspension array integrated the optical signal enhancement capability of the biomimetic microporous three-dimensional PCM surface with the thousand-fold signal amplification of LAMP. The biomimetic PCMs displayed a periodic dielectric nanostructure and enhanced the fluorescence intensity of the LAMP reaction, leading to high sensitivity. The PCM-LAMP suspension array allowed sensitive detection of the target DNA of S. aureus without long-term culture. Under optimal conditions, the limit of detection for S. aureus genomic DNA reached as low as 0.18 fM, and the assay exhibited excellent specificity against other bacteria. Furthermore, trace target DNA in food samples was accurately quantified, demonstrating its potential for practical applications. Therefore, the developed PCM-LAMP suspension array holds great promise for ultrasensitive and rapid detection of foodborne pathogens. Full article

Foodborne pathogens such as Klebsiella aerogenes pose a threat to food safety, highlighting the need for rapid, reliable detection methods amid rising contamination risks in production chains. In this study, a loop-mediated isothermal amplification (LAMP) assay was developed and validated to detect the histidine decarboxylase (HDC) gene of K. aerogenes. The assay was optimized for specificity and sensitivity, tested on pure bacterial genomic DNA and artificially contaminated food matrices (vegetables and meats), and evaluated against real-time PCR (qPCR). To evaluate performance under different DNA quality conditions and simulate laboratory versus on-site workflows, two extraction approaches were compared: a standard laboratory protocol yielding high-purity DNA and a crude extraction method producing low-purity DNA, mimicking the presence of inhibitors commonly encountered in routine analysis and enabling practical on-site detection where commercial kits are not feasible. The developed LAMP assay achieved maximum specificity with no cross-reactivity to related species, limits of detection of 240 fg/reaction for pure bacterial DNA and 0.4 pg/µL in K. aerogenes artificially contaminated food samples, and a reaction time under 30 min—outperforming real-time PCR in speed and robustness. This cost-effective method provides a scalable tool for near-real-time monitoring of K. aerogenes in food production, enhancing safety and enabling early outbreak detection. Full article

Dengue virus (DENV), an important mosquito-borne orthoflavivirus, represents a growing global threat due to its geographic expansion and recent outbreaks worldwide. In resource-limited endemic settings, the development of affordable diagnostic assays is needed. In this study, we developed and validated a colorimetric reverse transcription loop-mediated isothermal amplification assay (RT-LAMP) for the detection of DENV type 3 (DENV-3) using 95 previously diagnosed clinical samples from Southeastern Mexico. Primers targeting the 3′ untranslated region (3′ UTR) of DENV-3 were designed, and assay conditions were standardized. The colorimetric RT-LAMP DENV-3 system achieved a preliminary limit of detection of 1 × 10³ copies per reaction, with 90.7% sensitivity and 100% specificity. The colorimetric format enabled visual readout without specialized equipment, supporting its potential applicability in point-of-care and resource-limited settings. The developed colorimetric RT-LAMP detection for DENV-3 is intended as a rapid screening/triage tool that can trigger confirmatory testing or public-health actions. Full article

Molecular point-of-care testing (POCT) for respiratory infections has undergone remarkable advancement over the past two decades, driven by technological innovation and urgent clinical needs highlighted by the COVID-19 pandemic. This comprehensive systematic review was conducted following PRISMA 2020 guidelines, synthesizing evidence from 254 peer-reviewed studies published between 2006 and 2026, with detailed analysis of the 30 most relevant papers selected through a rigorous four-stage screening process. The review examines the evolution of molecular POCT technologies, including reverse transcription polymerase chain reaction (RT-PCR), loop-mediated isothermal amplification (LAMP), recombinase polymerase amplification (RPA), and CRISPR-based detection systems. Key findings demonstrate that modern molecular POCT platforms achieve diagnostic performance comparable to laboratory-based testing, with sensitivities ranging from 88% to 100% and specificities from 98% to 100%, while delivering results in 15 to 80 min. These technologies enable rapid, accurate detection of major respiratory pathogens, including SARS-CoV-2, influenza A/B, respiratory syncytial virus (RSV), and atypical bacteria. The integration of microfluidic systems, portable devices, and smartphone-based analysis has expanded access to testing in resource-limited settings, emergency departments, and wearable platforms. This review provides critical insights for clinicians, researchers, and policymakers regarding the current state, clinical applications, and future directions of molecular POCT for respiratory infections. Full article

CRISPR-Cas12a enables rapid and specific detection of PCR/LAMP (loop-mediated isothermal amplification) reaction products; however, this approach often requires open-tube manipulation, rendering it prone to cross-contamination. Here, we developed a novel one-pot reaction system that eliminated carryover contamination and facilitated endpoint detection using a CRISPR/Cas12a-based system. We leveraged the dependence of the CRISPR-Cas12a cleavage system on the protospacer-adjacent motif (PAM) to design PCR/LAMP primers that incorporated the PAM site (TTT) into amplified DNA. Pre-incubation of Cas12a with crRNA1 and crRNA2 using PCR/LAMP resulted in efficient cleavage of cross-contaminating DNA, while the target gene remained intact due to the lack of PAM sites. Furthermore, a Cas12a-detection complex (comprising Cas12a, crRNA3, trehalose, and the ssDNA probe) pre-stored on the lid was introduced to mix with the PCR/LAMP amplicons, which triggered the non-specific cleavage of fluorescent probes for direct visual detection under a blue LED instrument. This method effectively degraded up to 10⁶ copies of carryover contaminants within one hour, demonstrating the potential of one-pot detection methods in complex samples. Full article

Loop-mediated isothermal amplification (LAMP) is an innovative nucleic acid amplification technique that operates under isothermal conditions and is distinguished by its high analytical efficiency, cost-effectiveness, and operational simplicity. Unlike conventional molecular assays, LAMP does not require sophisticated instrumentation or highly specialized personnel, rendering it particularly suitable for diagnostic deployment in resource-limited settings. Reaction outcomes are typically determined through direct visual inspection, often via colorimetric readouts, further enhancing its applicability in decentralized and point-of-care contexts. Owing to these attributes, LAMP has emerged as a valuable tool for the diagnosis of infectious diseases, particularly in regions with constrained laboratory infrastructure. Its affordability, rapid turnaround time, and ease of implementation support large-scale testing during public health emergencies, including epidemics and outbreaks, thereby contributing to the reduction in disease burden. Timely and accurate pathogen detection using LAMP can substantially strengthen public health responses aimed at controlling and mitigating viral transmission. This review provides an overview of the LAMP methodology, with an emphasis on its application in the detection of viral pathogens with epidemic and pandemic potential. Dengue virus and influenza virus are discussed as representative model infections to illustrate the diagnostic performance and practical advantages of LAMP-based assays. In addition, we explore current challenges and future perspectives for the implementation of LAMP in resource-limited settings, highlighting the need for continued technological refinement and contextual adaptation to maximize its impact on global health initiatives. Full article

Phytoplasmas are obligate intracellular parasitic bacteria that infect over 1000 plant species globally, causing devastating diseases characterized by yellowing, witches’ broom, phyllody, and significant yield losses in economically important crops. The unculturable nature of these pathogens has historically hindered their study; however, advances in molecular biology and genomics have substantially accelerated progress over the past two decades. This review provides a comprehensive overview of current knowledge on phytoplasma diseases and control technologies. In terms of taxonomy, phytoplasmas are currently classified into 37 16Sr groups with over 150 subgroups based on 16S rRNA gene analysis, and approximately 50 ‘Candidatus Phytoplasma’ species have been formally named. Genomic studies have revealed that phytoplasmas possess highly reduced genomes (530–1350 kb) lacking many essential metabolic pathways, reflecting their obligate parasitic lifestyle. Regarding pathogenesis, secreted effector proteins such as SAP (Secreted Aster Yellows Witches’ Broom Protein), TENGU (tengu-su inducer), and SWP (Secreted Wheat Blue Dwarf Protein) manipulate plant hormone signaling and developmental processes, leading to characteristic disease symptoms. Detection technologies have evolved from traditional microscopy to molecular methods, including nested PCR, real-time quantitative PCR, loop-mediated isothermal amplification (LAMP), and CRISPR/Cas-based systems (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein), with AI-based image recognition and remote sensing emerging as promising tools for large-scale field monitoring. Integrated management strategies encompassing agricultural practices, insect vector control, biological control agents, induced resistance, and breeding for resistance are discussed. Finally, future research directions, including functional genomics, microbiome-based approaches, and precision agriculture technologies, are highlighted. This review aims to provide researchers and practitioners with a systematic reference for understanding phytoplasma biology and developing effective disease management strategies. Full article