An ultrasensitive and contamination-free on-site nucleic acid detection platform for Listeria monocytogenes based on the CRISPR-Cas12a system combined with recombinase polymerase amplification

LWT ◽  
2021 ◽  
pp. 112166
Author(s):  
Yachen Tian ◽  
Tao Liu ◽  
Cheng Liu ◽  
Qingqiang Xu ◽  
Shuiqin Fang ◽  
...  
Author(s):  
Pei Wang ◽  
Chao Ma ◽  
Xue Zhang ◽  
Lizhan Chen ◽  
Longyu Yi ◽  
...  

The pandemic of COVID-19 caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has led to more than 117 million reported cases and 2.6 million deaths. Accurate diagnosis technologies are vital for controlling this pandemic. Reverse transcription (RT)-based nucleic acid detection assays have been developed, but the strict sample processing requirement of RT has posed obstacles on wider applications. This study established a ligation and recombinase polymerase amplification (L/RPA) combined assay for rapid detection of SARS-CoV−2 on genes N and ORF1ab targeting the specific biomarkers recommended by the China CDC. Ligase-based strategies usually have a low-efficiency problem on RNA templates. This study has addressed this problem by using a high concentration of the T4 DNA ligase and exploiting the high sensitivity of RPA. Through selection of the ligation probes and optimization of the RPA primers, the assay achieved a satisfactory sensitivity of 101 viral RNA copies per reaction, which was comparable to RT-quantitative polymerase chain reaction (RT-qPCR) and other nucleic acid detection assays for SARS-CoV−2. The assay could be finished in less than 30 min with a simple procedure, in which the requirement for sophisticated thermocycling equipment had been avoided. In addition, it avoided the RT procedure and could potentially ease the requirement for sample processing. Once validated with clinical samples, the L/RPA assay would increase the practical testing availability of SARS-CoV-2. Moreover, the principle of L/RPA has an application potential to the identification of concerned mutations of the virus.


Author(s):  
Alain Laurent ◽  
Arnaud Burr ◽  
Thibault Martin ◽  
Frédéric Lasnet ◽  
Sébastien Hauser ◽  
...  

Open Medicine ◽  
2007 ◽  
Vol 2 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Koray Ergunay ◽  
Gulcin Altinok ◽  
Bora Gurel ◽  
Ahmet Pinar ◽  
Arzu Sungur ◽  
...  

AbstractIntrauterine Parvovirus B19 infections may cause fetal anemia, non-immune hydrops fetalis or abortion. This study focuses on the pathogenic role of Parvovirus B19 in non-immune hydrops fetalis at Hacettepe University, a major reference hospital in Turkey. Twenty-two cases of non-immune hydrops fetalis were retrospectively selected out of a total of 431 hydrops fetalis specimens from the Department of Pathology archieves. Paraffine embedded tissue sections from placental and liver tissues from each case were evaluated by histopathology, immunohistochemistry, nested PCR and commercial quantitative Real-time PCR. Viral DNA was detected in placental tissues by Real-time PCR in 2 cases (2/22, 9.1%) where histopathology also revealed changes suggestive of Parvovirus B19 infection. No significant histopathologic changes were observed for the remaining sections. Nested PCR that targets the VP1 region of the viral genome and immunohistochemistry for viral capsid antigens were negative for all cases. As a result, Parvovirus B19 is identified as the etiologic agent for the development of non-immune hydrops fetalis for 9.1% of the cases in Hacettepe University, Turkey. Real-time PCR is observed to be an effective diagnostic tool for nucleic acid detection from paraffine embedded tissues. Part of this study was presented as a poster at XIIIth International Congress of Virology, San Francisco, USA (Abstract V-572).


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