A Rapid and Sensitive Reverse Transcription-Loop-Mediated Isothermal Amplification (RT-LAMP) Assay for the Detection of Indian Citrus Ringspot Virus

Plant Disease ◽  
2020 ◽  
Author(s):  
Amol Kokane ◽  
Sunil Kokane ◽  
Ashish Warghane ◽  
Mrugendra G Gubyad ◽  
Ashwani Kumar Sharma ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Large Scale ◽  
Color Change ◽  
Lamp Assay ◽  
Single Step ◽  
Isothermal Amplification ◽  
Ringspot Virus ◽  
Lamp Method ◽  
Loop Mediated Isothermal Amplification ◽  
Field Samples

Indian citrus ringspot virus (ICRSV) is a devastating pathogen that has a particularly deleterious effect on the ‘Kinnow mandarin’, a commercial citrus crop cultivated in the north-west of India. ICRSV belongs to the Mandarivirus genus within the family of Alphaflexiviridae and has a positive sense single-stranded RNA (ssRNA) genome consisting of six open reading frames (ORFs). Severe cases of ICRSV result in a significant reduction in both the yield and quality of crops. Consequently, there is an urgent need to develop methods to detect ICRSV in an accurate and timely manner. Current methods involve a two-step reverse transcriptase-polymerase chain reaction (RT-PCR) that is time-consuming. Here, we describe a novel, one-step, reverse transcription-loop-mediated isothermal amplification (RT-LAMP) method for the sensitive and rapid detection of ICRSV. The RT-LAMP assay was standardized by designing and testing four different primers that targeted the coat protein gene of ICRSV. Amplification results were visualized by a color change after addition of SYBR Green I. The standardized RT-LAMP assay was highly specific and successfully detected all 35 ICRSV isolates tested from the Punjab and Haryana states of India. Furthermore, there was no cross-reaction with 17 isolates of five other citrus pathogens that are common in India. ICRSV-RT-LAMP assay developed in the present study is a simple, rapid, sensitive, and specific, technique. Moreover, the assay consists of only a single step and is more cost-effective than existing methods. This represents the first application of RT-LAMP for the detection of ICRSV. Our RT-LAMP assay is a powerful tool for the detection of ICRSV and will be particularly useful for large scale indexing of field samples in diagnostic laboratories, nurseries, and for quarantine applications.

scholarly journals Development of a loop-mediated isothermal amplification (LAMP) method for specific detection of Mycobacterium bovis

2021 ◽  
Vol 15 (1) ◽  
pp. e0008996
Author(s):  
Thoko Flav Kapalamula ◽  
Jeewan Thapa ◽  
Mwangala Lonah Akapelwa ◽  
Kyoko Hayashida ◽  
Stephen V. Gordon ◽  
...  
Keyword(s):  
Developing Countries ◽  
Mycobacterium Bovis ◽  
Color Change ◽  
Low Cost ◽  
Lamp Assay ◽  
Genomic Region ◽  
Isothermal Amplification ◽  
Diagnostic Methods ◽  
Lamp Method ◽  
Loop Mediated Isothermal Amplification

Bovine tuberculosis (TB) caused by Mycobacterium bovis is a significant health threat to cattle and a zoonotic threat for humans in many developing countries. Rapid and accurate detection of M. bovis is fundamental for controlling the disease in animals and humans, and for the proper treatment of patients as one of the first-line anti-TB drug, pyrazinamide, is ineffective against M. bovis. Currently, there are no rapid, simplified and low-cost diagnostic methods that can be easily integrated for use in many developing countries. Here, we report the development of a loop-mediated isothermal amplification (LAMP) assay for specific identification of M. bovis by targeting the region of difference 4 (RD4), a 12.7 kb genomic region that is deleted solely in M. bovis. The assay's specificity was evaluated using 139 isolates comprising 65 M. bovis isolates, 40 M. tuberculosis isolates, seven M. tuberculosis complex reference strains, 22 non-tuberculous mycobacteria and five other bacteria. The established LAMP detected only M. bovis isolates as positive and no false positives were observed using the other mycobacteria and non-mycobacteria tested. Our LAMP assay detected as low as 10 copies of M. bovis genomic DNA within 40 minutes. The procedure of LAMP is simple with an incubation at a constant temperature. Results are observed with the naked eye by a color change, and there is no need for expensive equipment. The established LAMP can be used for the detection of M. bovis infections in cattle and humans in resource-limited areas.

RAPID DIAGNOSIS OF BLUETONGUE VIRUS SEROTYPES 2 AND 12 INFECTION BY REVERSE TRANSCRIPTION LOOP-MEDIATED ISOTHERMAL AMPLIFICATION

2015 ◽  
Vol 41 (03) ◽  
pp. 187-196
Author(s):  
Jia-Ling Yang ◽  
Yi-Chia Li ◽  
Shu-Chia Hu ◽  
Fan Lee ◽  
Fun-In Wang
Keyword(s):  
Reverse Transcription ◽  
Bluetongue Virus ◽  
Lamp Assay ◽  
Isothermal Amplification ◽  
Universal Primers ◽  
Subclinical Infection ◽  
Loop Mediated Isothermal Amplification ◽  
Mouth Disease Virus ◽  
Field Samples

Bluetongue (BT), an arthropod-borne viral disease, is caused by the bluetongue virus (BTV), belonging to the genus Orbivirus of the family Reoviridae. Most species of ruminants are susceptible to BTV, but most infections go subclinical. These 'reservoir hosts' may potentially further increase the viral transmission and expansion of the disease; thus, detection of subclinical infection is important. To detect the BTV, a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed using primers targeted to six regions of the segment 5 (NS1) gene of the BTV2/KM/2003. The assay was completed in 1 h at a temperature 65°C, and the products were specifically digested with MboII enzyme presented in the target region. The in vitro sensitivity of the RT-LAMP was 100 copies, characterized by a qRT-PCR. The RT-LAMP did not cross-react with four tested common ruminant infectious agents, namely foot and mouth disease virus, goat pox virus, bovine herpesvirus 1, and Clostridium perfrigens. The RT-LAMP was applied to whole blood samples from 15 clinically healthy dairy cattle, and was able to detect BTV from 3/15 animals, and in particular 1 of the 3 animals was seronegative by cELISA. Positive RT-LAMP samples were reproducible. This RT-LAMP provides a simple, efficient, and sensitive method to specifically detect BTV and is suitable for the screening of field samples with a potential to pick up subclinical infection. The alignments of the outer primer region indicated matches of > 85% with 18 out of 26 BTV serotypes, implying its potential as universal primers.

Rapid detection of Betacoronavirus 1 from clinical fecal specimens by a novel reverse transcription loop-mediated isothermal amplification assay

2011 ◽  
Vol 24 (1) ◽  
pp. 174-177 ◽  
Author(s):  
Jun Qiao ◽  
Qingling Meng ◽  
Xuepeng Cai ◽  
Chuangfu Chen ◽  
Zaichao Zhang ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Rapid Detection ◽  
Lamp Assay ◽  
High Specificity ◽  
Isothermal Amplification ◽  
Clinical Samples ◽  
Lamp Method ◽  
Nucleocapsid Gene ◽  
Loop Mediated Isothermal Amplification ◽  
Amplification Assay

Betacoronavirus 1 (BCoV-1) is an important pathogen causing diarrhea in calves. In the current study, a novel reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for rapid detection of BCoV-1 was successfully developed. The primers were designed to target the highly conserved fragment of BCoV-1 nucleocapsid gene. The assay displayed high specificity detecting only BCoV-1 with no cross reaction with other viruses. When 418 clinical samples from 6 different geographical areas of Xinjiang province were tested by the RT-LAMP method, the results indicated that this test is a simple, rapid, accurate, and sensitive method for the detection of BCoV-1.

scholarly journals Validation of a single-step, single-tube reverse transcription loop-mediated isothermal amplification assay for rapid detection of SARS-CoV-2 RNA

2020 ◽  
Vol 69 (9) ◽  
pp. 1169-1178 ◽  
Author(s):  
Jean Y. H. Lee ◽  
Nickala Best ◽  
Julie McAuley ◽  
Jessica L. Porter ◽  
Torsten Seemann ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Reverse Transcription ◽  
Rapid Detection ◽  
Lamp Assay ◽  
Single Step ◽  
Isothermal Amplification ◽  
Assay Sensitivity ◽  
Single Tube ◽  
Clinical Specimens ◽  
Loop Mediated Isothermal Amplification

Introduction. The SARS-CoV-2 pandemic of 2020 has resulted in unparalleled requirements for RNA extraction kits and enzymes required for virus detection, leading to global shortages. This has necessitated the exploration of alternative diagnostic options to alleviate supply chain issues. Aim. To establish and validate a reverse transcription loop-mediated isothermal amplification (RT- LAMP) assay for the detection of SARS-CoV-2 from nasopharyngeal swabs. Methodology. We used a commercial RT-LAMP mastermix from OptiGene in combination with a primer set designed to detect the CDC N1 region of the SARS-CoV-2 nucleocapsid (N) gene. A single-tube, single-step fluorescence assay was implemented whereby 1 µl of universal transport medium (UTM) directly from a nasopharyngeal swab could be used as template, bypassing the requirement for RNA purification. Amplification and detection could be conducted in any thermocycler capable of holding 65 °C for 30 min and measure fluorescence in the FAM channel at 1 min intervals. Results. Assay evaluation by assessment of 157 clinical specimens previously screened by E-gene RT-qPCR revealed assay sensitivity and specificity of 87 and 100%, respectively. Results were fast, with an average time-to-positive (Tp) for 93 clinical samples of 14 min (sd±7 min). Using dilutions of SARS-CoV-2 virus spiked into UTM, we also evaluated assay performance against FDA guidelines for implementation of emergency-use diagnostics and established a limit-of-detection of 54 Tissue Culture Infectious Dose 50 per ml (TCID50 ml−1), with satisfactory assay sensitivity and specificity. A comparison of 20 clinical specimens between four laboratories showed excellent interlaboratory concordance; performing equally well on three different, commonly used thermocyclers, pointing to the robustness of the assay. Conclusion. With a simplified workflow, The N1 gene Single Tube Optigene LAMP assay (N1-STOP-LAMP) is a powerful, scalable option for specific and rapid detection of SARS-CoV-2 and an additional resource in the diagnostic armamentarium against COVID-19.

scholarly journals Rapid and Visual Identification of Chlorophyllum molybdites With Loop-Mediated Isothermal Amplification Method

2021 ◽  
Vol 12 ◽  
Author(s):  
Nan Wang ◽  
Zhiyong Zhao ◽  
Jie Gao ◽  
Enjing Tian ◽  
Wenjie Yu ◽  
...  
Keyword(s):  
Color Change ◽  
Low Cost ◽  
Food Poisoning ◽  
Lamp Assay ◽  
Forensic Analysis ◽  
Isothermal Amplification ◽  
Mushroom Poisoning ◽  
Lamp Method ◽  
Mushroom Species ◽  
Loop Mediated Isothermal Amplification

Chlorophyllum molybdites is a kind of common poisonous mushroom in China that is widely distributed in different areas. Food poisoning caused by accidentally eating C. molybdites has become more frequent in recent years. In 2019, there were 55 food poisoning incidents caused by eating this mushroom in China. Mushroom poisoning continues to be a common health issue of global concern. When mushroom poisoning occurs, an effective, simple, and rapid detection method is required for accurate clinical treatment or forensic analysis. For the first time, we established a loop-mediated isothermal amplification (LAMP) assay for the visual detection of C. molybdites. A set of specific LAMP primers was designed, and the specificity was confirmed against 43 different mushroom species. The LAMP method could detect as low as 1 pg of genomic DNA. Boiled mushrooms and artificial gastric-digested mushroom samples were prepared to test the applicability of the method, and the results showed that as low as 1% C. molybdites in boiled and digested samples could be successfully detected. The LAMP method can also be completed within 45 min, and the reaction results could be directly observed based on a color change under daylight by the naked eye. Therefore, the LAMP assay established in this study provides an accurate, sensitive, rapid, and low-cost method for the detection of C. molybdites.

scholarly journals Development and validation of a one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) for rapid detection of ZIKV in patient samples from Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Severino Jefferson Ribeiro da Silva ◽  
Keith Pardee ◽  
Udeni B. R. Balasuriya ◽  
Lindomar Pena
Keyword(s):  
Reverse Transcription ◽  
Rapid Detection ◽  
Quantitative Polymerase Chain Reaction ◽  
Rna Extraction ◽  
Lamp Assay ◽  
Isothermal Amplification ◽  
Serum Samples ◽  
Low Resource ◽  
Loop Mediated Isothermal Amplification ◽  
One Step

AbstractWe have previously developed and validated a one-step assay based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) for rapid detection of the Zika virus (ZIKV) from mosquito samples. Patient diagnosis of ZIKV is currently carried out in centralized laboratories using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR), which, while the gold standard molecular method, has several drawbacks for use in remote and low-resource settings, such as high cost and the need of specialized equipment. Point-of-care (POC) diagnostic platforms have the potential to overcome these limitations, especially in low-resource countries where ZIKV is endemic. With this in mind, here we optimized and validated our RT-LAMP assay for rapid detection of ZIKV from patient samples. We found that the assay detected ZIKV from diverse sample types (serum, urine, saliva, and semen) in as little as 20 min, without RNA extraction. The RT-LAMP assay was highly specific and up to 100 times more sensitive than RT-qPCR. We then validated the assay using 100 patient serum samples collected from suspected cases of arbovirus infection in the state of Pernambuco, which was at the epicenter of the last Zika epidemic. Analysis of the results, in comparison to RT-qPCR, found that the ZIKV RT-LAMP assay provided sensitivity of 100%, specificity of 93.75%, and an overall accuracy of 95.00%. Taken together, the RT-LAMP assay provides a straightforward and inexpensive alternative for the diagnosis of ZIKV from patients and has the potential to increase diagnostic capacity in ZIKV-affected areas, particularly in low and middle-income countries.

scholarly journals Essential properties and pitfalls of colorimetric Reverse Transcription Loop-mediated Isothermal Amplification as a point-of-care test for SARS-CoV-2 diagnosis

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Bruna de Oliveira Coelho ◽  
Heloisa Bruna Soligo Sanchuki ◽  
Dalila Luciola Zanette ◽  
Jeanine Marie Nardin ◽  
Hugo Manuel Paz Morales ◽  
...  
Keyword(s):  
Viral Load ◽  
Internal Control ◽  
Reverse Transcription ◽  
Color Change ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
False Negative ◽  
Isothermal Amplification ◽  
Clinical Samples ◽  
Loop Mediated Isothermal Amplification

Abstract Background SARS-CoV-2 Reverse Transcription Loop-mediated Isothermal Amplification (RT-LAMP) colorimetric detection is a sensitive and specific point-of-care molecular biology technique used to detect the virus in only 30 min. In this manuscript we have described a few nuances of the technique still not properly described in the literature: the presence of three colors clusters; the correlation of the viral load with the color change; and the importance of using an internal control to avoid false-negative results. Methods To achieve these findings, we performed colorimetric RT-LAMP assays of 466 SARS-CoV-2 RT-qPCR validated clinical samples, with color quantification measured at 434 nm and 560 nm. Results First we determinate a sensitivity of 93.8% and specificity of 90.4%. In addition to the pink (negative) and yellow (positive) produced colors, we report for the first time the presence of an orange color cluster that may lead to wrong diagnosis. We also demonstrated using RT-qPCR and RT-LAMP that low viral loads are related to Ct values > 30, resulting in orange colors. We also demonstrated that the diagnosis of COVID-19 by colorimetric RT-LAMP is efficient until the fifth symptoms day when the viral load is still relatively high. Conclusion This study reports properties and indications for colorimetric RT-LAMP as point-of-care for SARS-CoV-2 diagnostic, reducing false results, interpretations and optimizing molecular diagnostics tests application.

scholarly journals A loop-mediated isothermal amplification (LAMP) assay to identify isotype 1 β-tubulin locus SNPs in synthetic double-stranded Haemonchus contortus DNA

2021 ◽  
Author(s):  
Livio M. Costa-Junior ◽  
Umer N. Chaudhry ◽  
Philip J. Skuce ◽  
Seamus Stack ◽  
Neil D. Sargison
Keyword(s):  
Genetic Susceptibility ◽  
Management Practices ◽  
Anthelmintic Resistance ◽  
Lamp Assay ◽  
Gastrointestinal Nematode ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Snp Typing ◽  
Field Samples ◽  
Β Tubulin

AbstractDevelopment of sustainable gastrointestinal nematode (GIN) control strategies depends on the ability to identify the frequencies of drug-susceptible and resistant genotypes in GIN populations arising from management practices undertaken on individual farms. Resistance to BZ drugs in GINs has been shown to be conferred by the presence of defined SNPs in the isotype 1 β-tubulin locus. Loop-mediated isothermal amplification (LAMP) assays are amenable to use on a range of DNA templates and are potentially adaptable to use in practical, cost-effective, pen-side diagnostic platforms that are needed to detect anthelmintic resistance in the field. In this study, we designed primers and examined LAMP assays to detect each of the three major isotype 1 β-tubulin SNPs conferring genetic susceptibility to BZ drugs. We used artificial pools of synthetic DNA, containing different proportions of susceptible and resistant SNPs to determine reproducibility of the assays. We demonstrated the detection of each of the isotype 1 β-tubulin SNPs conferring susceptibility to BZ drugs using the optimal LAMP assay. Isotype 1 β-tubulin SNP typing was effective in detecting BZ susceptibility, but the accuracy was reduced in samples with less than 60 % susceptible DNA. Our results show the potential for LAMP SNP typing to detect genetic susceptibility or resistance to anthelmintic drugs in livestock GINs, and some of the limitations in our approach that will need to be overcome in order to evaluate this assay using field samples.

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