scholarly journals Multiplexed Droplet Loop-mediated Isothermal Amplification with Scorpion-shaped Probes and Fluorescence Microscopic Counting for Digital Quantification of Virus RNAs

2021 ◽  
Author(s):  
Ya-Ling Tan ◽  
A-Qian Huang ◽  
Li-Juan Tang ◽  
Jian-Hui Jiang
Keyword(s):  
Nucleic Acid ◽  
Prevention And Control ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Highly Sensitive ◽  
And Control ◽  
Digital Quantification ◽  
Microscopic Counting ◽  
Epidemic Diseases

Highly sensitive digital nucleic acid techniques are of great significance for the prevention and control of epidemic diseases. Here we report the development of multiplex droplet loop-mediated isothermal amplification (multiplexed...

scholarly journals Rapid and Visual Detection of SARS-CoV-2 Using Multiplex Reverse Transcription Loop-Mediated Isothermal Amplification Linked With Gold Nanoparticle-Based Lateral Flow Biosensor

2021 ◽  
Vol 11 ◽  
Author(s):  
Xu Chen ◽  
Qingxue Zhou ◽  
Shijun Li ◽  
Hao Yan ◽  
Bingcheng Chang ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Prevention And Control ◽  
Limit Of Detection ◽  
Rna Extraction ◽  
Lateral Flow ◽  
Isothermal Amplification ◽  
Clinical Samples ◽  
Loop Mediated Isothermal Amplification ◽  
The World ◽  
And Control

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus that has caused the outbreak of coronavirus disease 2019 (COVID-19) all over the world. In the absence of appropriate antiviral drugs or vaccines, developing a simple, rapid, and reliable assay for SARS-CoV-2 is necessary for the prevention and control of the COVID-19 transmission.MethodsA novel molecular diagnosis technique, named multiplex reverse transcription loop-mediated isothermal amplification, that has been linked to a nanoparticle-based lateral flow biosensor (mRT-LAMP-LFB) was applied to detect SARS-CoV-2 based on the SARS-CoV-2 RdRp and N genes, and the mRT-LAMP products were analyzed using nanoparticle-based lateral flow biosensor. The mRT-LAMP-LFB amplification conditions, including the target RNA concentration, amplification temperature, and time were optimized. The sensitivity and specificity of the mRT-LAMP-LFB method were tested in the current study, and the mRT-LAMP-LFB assay was applied to detect the SARS-CoV-2 virus from clinical samples and artificial sputum samples.ResultsThe SARS-CoV-2 specific primers based on the RdRp and N genes were valid for the establishment of mRT-LAMP-LFB assay to detect the SARS-CoV-2 virus. The multiple-RT-LAMP amplification condition was optimized at 63°C for 30 min. The full process, including reaction preparation, viral RNA extraction, RT-LAMP, and product identification, could be achieved in 80 min. The limit of detection (LoD) of the mRT-LAMP-LFB technology was 20 copies per reaction. The specificity of mRT-LAMP-LFB detection was 100%, and no cross-reactions to other respiratory pathogens were observed.ConclusionThe mRT-LAMP-LFB technique developed in the current study is a simple, rapid, and reliable method with great specificity and sensitivity when it comes to identifying SARS-CoV-2 virus for prevention and control of the COVID-19 disease, especially in resource-constrained regions of the world.

scholarly journals Detection and Control of Fusarium oxysporum from Soft Rot in Dendrobium officinale by Loop-Mediated Isothermal Amplification Assays

Biology ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1136
Author(s):  
Caiyun Xiao ◽  
Rongyu Li
Keyword(s):  
Fusarium Oxysporum ◽  
Integrated Management ◽  
Elongation Factor ◽  
Lamp Assay ◽  
Soft Rot ◽  
Isothermal Amplification ◽  
Dendrobium Officinale ◽  
Control Effect ◽  
Loop Mediated Isothermal Amplification ◽  
And Control

Soft rot causing Fusarium oxysporum is one of the most destructive diseases of Dendrobium officinale Kimura et Migo in China that reduces D. officinale yield and quality. A key challenge for an integrated management strategy for this disease is the rapid and accurate detection of F. oxysporum on D. officinale. Therefore, a new loop-mediated isothermal amplification (LAMP) assay was developed for this purpose. In this study, the primers were selected and designed using the translation elongation factor-1α (TEF-1α) gene region as the target DNA sequence in order to screen the best system of reaction of LAMP to detect F. oxysporum through optimizing different conditions of the LAMP reaction, including time, temperature, concentrations of MgSO4, and concentrations of inner and outer primers. The optimized system was able to efficiently amplify the target gene at 62 °C for 60 min with 1.2 μM internal primers, 0.4 μM external primers, 7 mM Mg2+, and 5 fg/µL minimum detection concentration of DNA for F. oxysporum. The amplified products could be detected with the naked eye after completion of the reaction with SYBR green I. We were better able to control the effect of soft rot in D. officinale using fungicides following a positive test result. Additionally, the control effect of synergism combinations against soft rot was higher than 75%. Thus, LAMP assays could detect F. oxysporum in infected tissues of D. officinale and soils in field, allowing for early diagnosis of the disease.

scholarly journals Development and Clinical Evaluation of Loop-Mediated Isothermal Amplification (LAMP) Assay for the Diagnosis of Human Visceral Leishmaniasis in Brazil

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Daniel Moreira de Avelar ◽  
Débora Moreira Carvalho ◽  
Ana Rabello
Keyword(s):  
Visceral Leishmaniasis ◽  
Lamp Assay ◽  
Isothermal Amplification ◽  
Health Concern ◽  
Serological Tests ◽  
Blood Samples ◽  
Loop Mediated Isothermal Amplification ◽  
Human Visceral Leishmaniasis ◽  
Highly Sensitive ◽  
Sensitivity Specificity

Visceral leishmaniasis (VL) is considered a major public health concern in Brazil and several regions of the world. A recent advance in the diagnosis of infectious diseases was the development of loop-mediated isothermal amplification (LAMP). The aim of this study was to develop and evaluate a new LAMP assay for detection of K26 antigen-coding gene of L. donovani complex. A total of 219 blood samples of immunocompetent patients, including 114 VL cases and 105 non-VL cases, were analyzed for the diagnosis of VL in the present study. Diagnostic accuracy was calculated against a combination of parasitological and/or serological tests as a reference standard. The results were compared to those of kDNA Leishmania-PCR. The detection limit for the K26-Lamp assay was 1fg L. infantum purified DNA and 100 parasites/mL within 60 min of amplification time with visual detection for turbidity. The assay was specific for L. donovani complex. Sensitivity, specificity, and accuracy were 98.2%, 98.1%, and 98.2%, respectively, for K26-LAMP and 100%, 100%, and 100%, respectively, for kDNA Leishmania-PCR. Excellent agreement was observed between K26-LAMP and kDNA Leishmania-PCR assays (K = 0.96). A highly sensitive and specific LAMP assay targeting K26 antigen-coding gene of L. donovani complex was developed for diagnosis in peripheral blood samples of VL patients.

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