scholarly journals Detecting Phytophthora cinnamomi associated with dieback disease on Carya cathayensis using loop-mediated isothermal amplification

2021 ◽  
Author(s):  
Xiaoqing Tong ◽  
Jiayi Wu ◽  
Li Mei ◽  
Yongjun Wang

AbstractChinese hickory (Carya cathayensis Sarg.) is an economically and ecologically important nut plant in China. Dieback and basal stem necrosis have been observed in the plants since 2016, and its recent spread has significantly affected plant growth and nut production. Therefore, a survey was conducted to evaluate the disease incidence at five sites in Linan County, China. The highest incidence was recorded at the Tuankou site at up to 11.39% in 2019. The oomycete, Phytophthora cinnamomi, was isolated from symptomatic plant tissue and plantation soil using baiting and selective media-based detection methods and identified. Artificial infection with the representative P. cinnamomi ST402 isolate produced vertically elongated discolorations in the outer xylem and necrotic symptoms in C. cathayensis seedlings in a greenhouse trial. Molecular detections based on loop-mediated isothermal amplification (LAMP) specific to P. cinnamomi ST402 were conducted. Result indicated that LAMP detection showed a high coherence level with the baiting assays for P. cinnamomi detection in the field. This study provides the evidence of existence of high-pathogenic P. cinnamomi in the C. cathayensis plantation soil in China and the insights into a convenient tool developed for conducting field monitoring of this aggressive pathogen.

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0257785
Author(s):  
Xiaoqing Tong ◽  
Jiayi Wu ◽  
Li Mei ◽  
Yongjun Wang

Chinese hickory (Carya cathayensis Sarg.) is an economically and ecologically important nut plant in China. Dieback and basal stem necrosis have been observed in the plants since 2016, and its recent spread has significantly affected plant growth and nut production. Therefore, a survey was conducted to evaluate the disease incidence at five sites in Linan County, China. The highest incidence was recorded at the Tuankou site at up to 11.39% in 2019. The oomycete, Phytophthora cinnamomi, was isolated from symptomatic plant tissue and plantation soil using baiting and selective media-based detection methods and identified. Artificial infection with the representative P. cinnamomi ST402 isolate produced vertically elongated discolorations in the outer xylem and necrotic symptoms in C. cathayensis seedlings in a greenhouse trial. Molecular detections based on loop-mediated isothermal amplification (LAMP) specific to P. cinnamomi ST402 were conducted. Result indicated that LAMP detection showed a high coherence level with the baiting assays for P. cinnamomi detection in the field. This study provides the evidence of existence of high-pathogenic P. cinnamomi in the C. cathayensis plantation soil in China and the insights into a convenient tool developed for conducting field monitoring of this aggressive pathogen.


Sensors ◽  
2015 ◽  
Vol 15 (3) ◽  
pp. 5376-5389 ◽  
Author(s):  
Shah Uddin ◽  
Fatimah Ibrahim ◽  
Abkar Sayad ◽  
Aung Thiha ◽  
Koh Pei ◽  
...  

In recent years, many improvements have been made in foodborne pathogen detection methods to reduce the impact of food contamination. Several rapid methods have been developed with biosensor devices to improve the way of performing pathogen detection. This paper presents an automated endpoint detection system for amplicons generated by loop mediated isothermal amplification (LAMP) on a microfluidic compact disk platform. The developed detection system utilizes a monochromatic ultraviolet (UV) emitter for excitation of fluorescent labeled LAMP amplicons and a color sensor to detect the emitted florescence from target. Then it processes the sensor output and displays the detection results on liquid crystal display (LCD). The sensitivity test has been performed with detection limit up to 2.5 × 10−3 ng/µL with different DNA concentrations of Salmonella bacteria. This system allows a rapid and automatic endpoint detection which could lead to the development of a point-of-care diagnosis device for foodborne pathogens detection in a resource-limited environment.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nupur Garg ◽  
Upasana Sahu ◽  
Sudeshna Kar ◽  
Farhan J. Ahmad

AbstractLeprosy, a progressive, mutilating and highly stigmatized disease caused by Mycobacterium leprae (ML), continues to prevail in the developing world. This is due to the absence of rapid, specific and sensitive diagnostic tools for its early detection since the disease gets notified only with the advent of physical scarring in patients. This study reports the development of a Loop-mediated isothermal amplification (LAMP) technique for fast, sensitive and specific amplification of 16S rRNA gene of ML DNA for early detection of leprosy in resource-limited areas. Various parameters were optimized to obtain robust and reliable amplification of ML DNA. Blind clinical validation studies were performed which showed that this technique had complete concurrence with conventional techniques. Total absence of amplification of negative control DNA confirmed the specificity of this test. Various visual detection methods viz. colorimetric, turbidity differentiation and bridge flocculation were standardized to establish easy-to-read and rapid diagnosis. This technique eliminates the lack of accuracy and sensitivity in skin smear tests in patients and the requirement for expensive lab equipments and trained technicians. The technique holds promise for further expansion and has the potential to cater to the unmet needs of society for a cheap, highly-sensitive and robust rapid diagnosis of ML.


2015 ◽  
Vol 41 (04) ◽  
pp. 251-255
Author(s):  
Lih-Chiann Wang ◽  
Dean Huang

H7N9 avian influenza viruses have circulated in the human population and poultry flocks in China since 2013. H7N9 virus monitoring is imperative in Taiwan due to the frequent contact between China and Taiwan. Traditional viral molecular detection methods using RT-PCR and sequencing are time- and labor-intensive, thus a simpler and cheaper method with high sensitivity and specificity is worth developing. We successfully detected human and wild bird H7N9 viruses in this study using reverse transcription loop-mediated isothermal amplification (RT-LAMP) and oligonucleotide microarray. The detection limit was as low as one viral copy number. The specific matching reaction between the templates and microarray probes during hybridization ensured the high detection effectiveness. The excellent sensitivity and specificity of the RT-LAMP-microarray makes it a powerful H7N9 surveillance approach in Taiwan.


2020 ◽  
Author(s):  
Yuhua Li ◽  
Haoran Li ◽  
Xiaoxiao Song ◽  
Hao Zhang ◽  
Yujuan Duan ◽  
...  

Abstract Background: Trichomoniasis resulting from Trichomonas vaginalis (T. vaginalis) has been considered as a commonly seen disease with the transmission way of sex. At present, the detection methods of T. vaginalis mainly include wet mount microscopy, culture, PCR, immunofluorescence and ELISA. However, all of these detection methods exist shortcomings.Methods: In this study, a loop-mediated isothermal amplification (LAMP) assay that targeted the species-specific sequence of adhesion protein 65 (AP65) gene had been conducted to detect T. vaginalis. The optimum reaction system and conditions were optimized in this rapid detection method.Results: The results of sensitivity analysis showed that the LAMP assay targeting the AP65 gene was 1000 times more sensitive than the nested PCR targeting the actin gene commonly used for detection of T. vaginalis, and the detecting limitation of the former was 10 trichomonad. Moreover, the amplification of the target gene AP65 by LAMP assay exhibited high specificity and the product was exclusively from T. vaginalis. The detection technique of LAMP did not exhibit cross-reactivity with the common pathogens of Trichinella spiralis, Toxoplasma gondii, Escherichia coli, Candida albicans, Staphylococcus aureus, Haemophilus.Conclusions: According to the present study, the LAMP assay with the target of AP65 gene, was suitable for the early diagnosis of T. vaginalis infections. Consequently, the LAMP assay was proposed by the current study as a point-of-care examination and an alternative molecular tool which exhibited the potential value in the treatment, control and prevention of trichomoniasis transmission and relevant complication.


2020 ◽  
Author(s):  
Yuhua Li ◽  
Shuai Wang ◽  
Haoran Li ◽  
Xiaoxiao Song ◽  
Hao Zhang ◽  
...  

Abstract Background: Trichomoniasis resulting from Trichomonas vaginalis (T. vaginalis) has been considered as a commonly seen disease with the transmission way of sex. At present, the detection methods of T. vaginalis mainly include wet mount microscopy, culture, PCR, immunofluorescence and ELISA. However, all of these detection methods exist shortcomings. Methods: In this study, a loop-mediated isothermal amplification (LAMP) assay that targeted the species-specific sequence of adhesion protein 65 (AP65) gene had been conducted to detect T. vaginalis. The optimum reaction system and conditions were optimized in this rapid detection method. Results: The results of sensitivity analysis showed that the LAMP assay targeting the AP65 gene was 1000 times more sensitive than the nested PCR targeting the actin gene commonly used for detection of T. vaginalis, and the detecting limitation of the former was 10 trichomonad. Moreover, the amplification of the target gene AP65 by LAMP assay exhibited high specificity and the product was exclusively from T. vaginalis. The detection technique of LAMP did not exhibit cross-reactivity with the common pathogens of Trichinella spiralis, Toxoplasma gondii, Escherichia coli, Candida albicans, Staphylococcus aureus, Haemophilus. Conclusions: According to the present study, the LAMP assay with the target of AP65 gene, was suitable for the early diagnosis of T. vaginalis infections. Consequently, the LAMP assay was proposed by the current study as a point-of-care examination and an alternative molecular tool which exhibited the potential value in the treatment, control and prevention of trichomoniasis transmission and relevant complication.


Author(s):  
Yanhong Liu ◽  
Deguo Wang ◽  
Meng Zhang ◽  
Yanhong Liu ◽  
Yongzhen Wang

Salmonella spp. are important food-borne pathogens that can cause diseases in humans. Many detection methods have been established in Salmonella spp. using loop-mediated isothermal amplification (LAMP) or reverse transcription loop-mediated isothermal amplification (RT-LAMP). The detection limits of these assays varied from 1 CFU/reaction to 104 CFU/reaction, from 100 fg genomic DNA/reaction to 10 pg genomic DNA/reaction, or from 2.0×101 CFU/mL to 107 CFU/mL for food samples. In this study, LAMP assays were developed using genomic DNA for the detection of Salmonella spp. Two sets of LAMP primers were designed using the invA gene and the 16S-23S rRNA intergenic spacer region (ITS) of S. enterica as the target sequences for two LAMP assays. The detection limits of the two methods were respectively 20 pg S. enterica DNA/reaction and 10 pg S. enterica DNA/reaction at the optimized temperature, and the LAMP methods were of high repeatability and specificity for S. enterica detection. This study provides a baseline for the application of LAMP for the detection of food-borne pathogenic bacteria.


2014 ◽  
Vol 8 (6) ◽  
pp. 316-321 ◽  
Author(s):  
Wentao Yang ◽  
Xiaoning Song ◽  
Jingxin Wang ◽  
Zhen Li ◽  
Mingjiang Ji ◽  
...  

2011 ◽  
Vol 77 (12) ◽  
pp. 4008-4016 ◽  
Author(s):  
Siyi Chen ◽  
Fei Wang ◽  
John C. Beaulieu ◽  
Rebecca E. Stein ◽  
Beilei Ge

ABSTRACTRecent outbreaks linked toSalmonella-contaminated produce heightened the need to develop simple, rapid, and accurate detection methods, particularly those capable of determining cell viability. In this study, we examined a novel strategy for the rapid detection and quantification of viable salmonellae in produce by coupling a simple propidium monoazide sample treatment with loop-mediated isothermal amplification (PMA-LAMP). We first designed and optimized a LAMP assay targetingSalmonella. Second, the performance of PMA-LAMP for detecting and quantifying viable salmonellae was determined. Finally, the assay was evaluated in experimentally contaminated produce items (cantaloupe, spinach, and tomato). Under the optimized condition, PMA-LAMP consistently gave negative results for heat-killedSalmonellacells with concentrations up to 108CFU/ml (or CFU/g in produce). The detection limits of PMA-LAMP were 3.4 to 34 viableSalmonellacells in pure culture and 6.1 × 103to 6.1 × 104CFU/g in spiked produce samples. In comparison, PMA-PCR was up to 100-fold less sensitive. The correlation between LAMP time threshold (TT) values and viableSalmonellacell numbers was high (R2= 0.949 to 0.993), with a quantification range (102to 105CFU/reaction in pure culture and 104to 107CFU/g in produce) comparable to that of PMA in combination with quantitative real-time PCR (PMA-qPCR). The complete PMA-LAMP assay took about 3 h to complete when testing produce samples. In conclusion, this rapid, accurate, and simple method to detect and quantify viableSalmonellacells in produce may present a useful tool for the produce industry to better control potential microbial hazards in produce.


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