Rice bacterial leaf brown spot disease caused by Pseudomonas syringae pv.syringae(Pss)is a major disease on rice.In recent years,Pss has emerged worldwide,seriously affecting rice production.It is very important to es...Rice bacterial leaf brown spot disease caused by Pseudomonas syringae pv.syringae(Pss)is a major disease on rice.In recent years,Pss has emerged worldwide,seriously affecting rice production.It is very important to establish a rapid detection method of Pss for the diagnosis and prevention of this disease.In order to robust and accurately diagnose the rice bacterial leaf brown spot disease in the field and laboratory,an assay system for the Pss was developed in this study,and the specific sequence of hrcN was used as the target,based on loop-mediated isothermal amplification(LAMP).The best detection system was MgSO 48 mmol·L^(-1),Bst DNA polymerase 8 U,dNTP 1.4 mmol·L^(-1),the ratio of internal and outer primers was 2:1,the reaction temperature was 63℃,the reaction time was 45 min,and the lowest sensitivity was 104 CFU·mL^(-1).This results provided an accurate and robust method for laboratory and field diagnosis of bacterial leaf brown spot disease of rice.展开更多
[Objective] To develop a rapid and visualized detection method using loop-mediated isothermal amplification (LAMP), improve the detection rate of canine parvovirus (CPV) and reduce the testing cost. [Method] According...[Objective] To develop a rapid and visualized detection method using loop-mediated isothermal amplification (LAMP), improve the detection rate of canine parvovirus (CPV) and reduce the testing cost. [Method] According to the conserved regions of the VP2 gene of CPV, six primers were designed to amplify the special DNA sequences by LAMP. In addition, the reaction conditions of LAMP were optimized, and the sensitivity, specificity, repeatability and stability were verified. [Result] The optimal reaction time of the LAMP method for CPV was 60 min. The products obtained by LAMP had high specificity without cross-reaction with other generic viruses. The sensitivity of the LAMP was 100 times higher than that of PCR. [Conclusion] The LAMP method for detecting CPV has high practical value. It has many advantages such as high specificity, high sensitivity, simple operation, low cost and rapid analysis, and it does not require special equipment. Therefore, this method is more suitable for the detection of CPV.展开更多
Objective:To develop a loop-mediated isothermal amplification(LAMP) assay for the detection of Entamoeba histolytica(E.histolytica),the causative agent of amebiasis.Methods:The LAMP primer set was designed from E.hist...Objective:To develop a loop-mediated isothermal amplification(LAMP) assay for the detection of Entamoeba histolytica(E.histolytica),the causative agent of amebiasis.Methods:The LAMP primer set was designed from E.histolytica hemolysin gene HLY6.Genomic DNA of E.histolytica trophozoites strain HK9 was used to optimize the LAMP mixture and conditions.Amplification of DNA in the LAMP mixture was monitored through visual inspection for turbidity of the LAMP mix as well as addition of fluorescent dye.Results:Positive LAMP reactions turned turbid while negative ones remained clear.Upon addition of a fluorescent dye,all positive reactions turned green while the negative control remained orange under ambient light After elecrophoresis in 1.5% agarose gels,a ladder of multiple bands of different sizes can be oliserved in positive samples while no bands were detected in the negative control.The sensitivity of the assay was found to be S parasites per reaction which corresponds to approximately 1S.8 ng/μL DNA.The specificity of the assay was verified by the absence of amplified products when DNA from other gastrointestinal parasites such as the morphologically similar but non-pathogenic species,Entamoeba dispar. and other diarrhea-causing organisms such as Blastocystis hominis and Escherichia coli were used.Conclusions:The I.AMP assay we have developed enables the detection of E.histolytica with rapidity and ease,therefore rendering it is suitable for laboratory and field diagnosis of amebiasis.展开更多
Pectobacterium carotovorum is the causal agent of bacterial soft rot in a wide range of vegetable host species.Once P.carotovorum infects the plant,the spread of the disease is difficult to control.In this study,a rap...Pectobacterium carotovorum is the causal agent of bacterial soft rot in a wide range of vegetable host species.Once P.carotovorum infects the plant,the spread of the disease is difficult to control.In this study,a rapid and sensitive method based on loop-mediated isothermal amplification(LAMP)was developed for detecting P.carotovorum in celery with soft rot using a primer set designed from the pmrA conserved sequence of P.carotovorum.The specificity of the LAMP primer set for P.carotovorum was extensively validated on both P.carotovorum strains and nontarget strains.The sensitivity was 1 pg of P.carotovorum genomic DNA,which demonstrated 10 times more sensitive than the conventional PCR assay.LAMP was also used to detect P.carotovorum in bacterial suspension.The lowest detection concentration was 104 CFU·mL^−1.In addition,a LAMP assay,in conjunction with a crude DNA extraction method,was successfully performed on P.carotovorum-infected samples derived from both artificially and naturally infected plants.In summary,the LAMP assay established in this study constitutes a simple,sensitive,and rapid method for the detection of P.carotovorum,and has potential application in the control of celery soft rot disease through early detection.展开更多
A sensitive reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for human enterovirus 71 (EV71) and Coxsackievirus A16 (CVA16) infection was further evaluated. The one step reaction was perfor...A sensitive reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for human enterovirus 71 (EV71) and Coxsackievirus A16 (CVA16) infection was further evaluated. The one step reaction was performed in a single tube at 65?C for 45 min for EV71 and 35 min for CVA16. The detection limits of RT-LAMP assays for both EV71 and CVA16 were 0.1 of a 50% tissue culture infective dose (TCID50) per reaction, based on 10—Fold dilutions of a titrated EV71 or CVA16 strain. The specific assay showed there were no cross-reactions with Coxsackievirus A (CVA) viruses (CVA 2, 4, 5, 7, 9, 10, 14, and 25), Coxsackievirus B (CVB) viruses (CVB 1, 2, 3, 4, and 5) or ECHO viruses (ECHO 3, 6, 11, and 19). In parallel with commercial quantitative real-time polymerase chain reaction (qRT-PCR) diagnostic kits for EV71 and CVA16, the RT-LAMP assay was evaluated with 515 clinical specimens, the results showed the RT-LAMP assay and the qRT-PCR assay were in complete agreement for 513/515 (99.6%) of the specimens. Two samples with discrepant results from two methods were further verified by nested reverse transcription polymerase chain reaction (nRT-PCR) assay and sequencing to be true positives for CVA16. In conclusion, RT-LAMP assay is demonstrated to be a sensitive and specific assay and have a great potential for the rapid and visual screening of EV71 and CVA16 in China, especially in those resource-limited hospitals and rural clinics of provincial and municipal regions.展开更多
Plague caused by Yersinia pestis is one of the infectious diseases subject to the International Health Regulations (IHR). Permanent monitoring of the focal plague areas is mandatory in order to enable prompt control m...Plague caused by Yersinia pestis is one of the infectious diseases subject to the International Health Regulations (IHR). Permanent monitoring of the focal plague areas is mandatory in order to enable prompt control measures to prevent the spread of the disease. Therefore, the availability of efficient diagnosis tests is of paramount importance. Here, we describe a loop-mediated isothermal amplification (LAMP)-based procedure for rapid Y. pestis detection. We constructed a set of LAMP primers, which were used in assays to establish the reaction conditions that would lead to the quick visualization of the results by evaluating the test tube with the naked eye. The primers were specifically designed to target the caf1 gene located on pFra/Tox (pMT), a prototypical plasmid of Y. pestis. The LAMP procedure was performed at 65°C for 45 min in a water bath and allowed for the detection of at least 10 pg of bacterial DNA. Due to its simplicity, specificity, sensitivity and rapidity, the LAMP technique is an additional tool that may be implemented in routine plague diagnoses, especially in emergencies.展开更多
The rapid and accurate detection of peanuts and soybeans allergen is important to the food safety. In this study, Cu-TCPP nanosheet, a kind of ultra-thin metal-organic framework(MOF)was synthesized and applied in loop...The rapid and accurate detection of peanuts and soybeans allergen is important to the food safety. In this study, Cu-TCPP nanosheet, a kind of ultra-thin metal-organic framework(MOF)was synthesized and applied in loop-mediated isothermal amplification(named Cu-TCPP@LAMP), which can inhibit the non-specific amplification by absorbing and precise temperature releasing of single primer. As thus, Cu-TCPP@LAMP can achieve high sensitivity and specific amplification of the target gene. As a result, peanut and soybean allergens genes contained in food were successfully detected with a favorable detection sensitivity(5 ng/μL for peanuts and 10 ng/μL for soybeans)and reliable repeatability(The coefficient of variation was 3.38% for peanuts and 3.33% for soybeans). Moreover, the established method was utilized for detection of several commercial products, and had a high consistency with the standard method. Apart from food allergens, this novel assay can be widely used in other areas, such as pathogen detection, tumor nucleic acid detection and so on.展开更多
When the loop-mediated isothermal amplification(LAMP)assay is used for detecting target genes,DNA extraction is unnecessary in many cases.Simple pretreatment(e.g.heating)is enough to obtain rather sensitive responses....When the loop-mediated isothermal amplification(LAMP)assay is used for detecting target genes,DNA extraction is unnecessary in many cases.Simple pretreatment(e.g.heating)is enough to obtain rather sensitive responses.Even test samples without any pretreatment can be used as template.This feature suggests that LAMP is superior to PCR in developing point-of-care test strategies.In this study,using Stx1 gene from E.coli as model,we verified that viable cells,dead cells and extracellular DNA could function as template in the LAMP assay.In the incubation at 63℃,viable bacteria in the LAMP reaction mixture lysed completely within 2 min,providing DNA template for nucleic acid amplification.The Stx1 gene in diluted culture medium,spiked tap water,spiked seawater and real seawater all could be detected,with or without the step of DNA extraction.We found that the complex substances in real sample(e.g.natural seawater)exhibited considerable inhibitory effect on the sensitivity of the LAMP assay.These outcomes are meaningful for building a point-of-care strategy by employing the LAMP assay for environmental monitoring,bio-resource surveys,food safety,etc.in particular those based on environmental DNA.展开更多
Rapid,sensitive,point-of-care detection of pathogenic bacteria is important for food safety.In this study,we developed a novel quantum dot nanobeads-labelled lateral flow immunoassay strip(QBs-labelled LFIAS)combined ...Rapid,sensitive,point-of-care detection of pathogenic bacteria is important for food safety.In this study,we developed a novel quantum dot nanobeads-labelled lateral flow immunoassay strip(QBs-labelled LFIAS)combined with strand displacement loop-mediated isothermal amplification(SD-LAMP)for quantitative Salmonella Typhimurium(ST)detection.Quantum dot nanobeads(QBs)served as fluorescence reporters,providing good detection efficiency.The customizable strand displacement(SD)probe was used in LAMP to improve the specificity of the method and prevent by-product capture.Detection was based on a sandwich immunoassay.A fluorescence strip reader measured the fluorescence intensity(FI)of the test(T)line and control(C)line.The linear detection range of the strip was 10^(2)–10^(8) colony forming units(CFU)·mL^(-1).The visual limit of detection was 10^(3) CFU·mL^(-1),indicating that the system was ten-fold more sensitive than AuNPs-labelled test strips.ST specificity was analyzed in accordance with agarose gel outputs of polymerase chain reaction(PCR)and SD-LAMP.We detected ST in foods with an acceptable recovery of 85%–110%.The method is rapid,simple,almost equipment-free,and suitable for bacterial detection in foods and for clinical diagnosis.展开更多
Apple bitter rot is a serious agricultural disease caused by Colletotrichum gloeosporioides.In recent years,carbendazim-resistant C.gloeosporioides strains bearing an E198A point mutation in theβ-tubulin gene(GAG to ...Apple bitter rot is a serious agricultural disease caused by Colletotrichum gloeosporioides.In recent years,carbendazim-resistant C.gloeosporioides strains bearing an E198A point mutation in theβ-tubulin gene(GAG to GCG)have emerged,threatening global apple production.As such,rapidly detecting the presence of this E198Amutation in C.gloeosporioides isolates is essential in order to monitor the spread of this pathogen and to prevent outbreaks of disease.Herein,we developed a simple loop-mediated isothermal amplification(LAMP)approach to detecting the E198A mutation in C.gloeosporioides isolates from‘Gala’apple samples.This optimized LAMP protocol was sufficient to establish the E198A genotype of a given isolate following a 60min incubation at 63℃ by using four specific primers.The results of this reaction could be interpreted visually based on a fluorescent yellow-green color change upon the addition of the SYBR Green I dye,and were additionally confirmed via gel electrophoresis.Importantly,this LAMP assay was capable of rapidly and reliably detecting apples that were infected with carbendazim-resistant isolates harboring this E198A mutation.In conclusion,this LAMP assay in this study can rapidly,specifically,and sensitively detect cases of apple bitter rot caused by C.gloeosporioides isolates harboring the E198A mutation.展开更多
In the last decade,some disease occurred on our experimental farms that had caused serious losses.They were not caused by fungi,bacteria or viruses.By loop-mediated isothermal amplification(LAMP)technique,the detectio...In the last decade,some disease occurred on our experimental farms that had caused serious losses.They were not caused by fungi,bacteria or viruses.By loop-mediated isothermal amplification(LAMP)technique,the detection results pointed to the possible pathogen as phytoplasma.The investigation results implied that phytoplasmas could cause more than 13 kinds of symptoms in almost all parts of plants in B.napus L.,including witches’broom,multi-stems,aggregate main inflorescences,and flat stems.The incidences of these phytoplasma-associated diseases in our experimental farms rose from 1.61%in 2010 to 6.00%in 2021.Some phytoplasma infected plants died without any growing points.These studies would be helpful for detecting phytoplasmas diseases,selecting disease resistant germplasm and improving varieties with disease resistances in B.napus L.展开更多
[Objectives]Loop-mediated isothermal amplification(LAMP)was developed and optimized for rapid and specific diagnosis of Brucella infection.[Methods]The conserved sequence of the brucellosis standard strain Omp25 gene ...[Objectives]Loop-mediated isothermal amplification(LAMP)was developed and optimized for rapid and specific diagnosis of Brucella infection.[Methods]The conserved sequence of the brucellosis standard strain Omp25 gene fragment was selected,primers needed in the loop-mediated isothermal amplification system were designed,and nucleic acid of the standard strain was extracted.Primers,reaction system,reaction conditions and stain types were repeatedly optimized to establish an improved LAMP detection kit for brucellosis.Confirmatory tests were performed on blood samples from clinically confirmed cases and their sensitivity and specificity were confirmed.Then,the detection technology and kit were applied to the detection and screening of suspected B.melitensis in pastoral areas.Finally,SPSS21.0 was used to evaluate the consistency of LAMP and Q-PCR.[Results]LAMP system was optimized,and the optimal final concentrations of MgSO_(4) and betaine were 8 and 0.8 mmol/L,respectively.The sensitivity and specificity of the modified LAMP technique were verified by using human blood samples with confirmed brucellosis.In LAMP specific test,there was no nonspecific amplification,indicating good specificity.In the LAMP sensitivity test,the minimum detection line for B.melitensis,B.abortus,and B.suis was 10 copies/μL,which was an order of magnitude higher than that for Q-PCR.The consistency between modified LAMP and Q-PCR was 0.941.The established Brucella LAMP kit was used to detect the blood samples of 200 sheep suspected to be infected with Brucella.The LAMP kit detected 42 positive samples,with a positive rate of 21%and a detection sensitivity of 100%.Negative specimens were detected in 158 cases,with a specificity of 100%.There were 41 negative samples detected by PCR,with a positive rate of 20.5%.The detection specificity was consistent with that of LAMP kit.[Conclusions]The modified LAMP for Brucella has been successfully established.This technology is characterized by good sensitivity and specificity,low cost and high efficiency,and is conducive to the development in primary medical institutions.展开更多
Nucleic acid(DNA and RNA)detection and quantification methods play vital roles in molecular biology.With the development of molecular biology,isothermal amplification of DNA/RNA,as a new molecular biology technology,c...Nucleic acid(DNA and RNA)detection and quantification methods play vital roles in molecular biology.With the development of molecular biology,isothermal amplification of DNA/RNA,as a new molecular biology technology,can be amplified under isothermal condition,it has the advantages of high sensitivity,high specificity,and high efficiency,and has been applied in various fields of biotechnology,including disease diagnosis,pathogen detection,food hygiene and safety detection and so on.This paper introduces the progress of isothermal amplification technology,including rolling circle amplification(RCA),nucleic acid sequence-dependent amplification(NASBA),strand displacement amplification(SDA),loop-mediated isothermal amplification(LAMP),helicase-dependent amplification(HDA),recombinase polymerase amplification(RPA),cross-priming amplification(CPA),and its principle,advantages and disadvantages,and application development are briefly summarized.展开更多
Objective:To establish a novel and highly specific loop-mediated isothermal amplification(LAMP) assay for the identification of nervous necrosis virus(NNV) infection.Methods:A set of synthesized primers was used to ma...Objective:To establish a novel and highly specific loop-mediated isothermal amplification(LAMP) assay for the identification of nervous necrosis virus(NNV) infection.Methods:A set of synthesized primers was used to match the sequences of a specific region of the nnr gene from the National Center for Biotechnology Information database,not originating from NNV-infected fish,the efficiency and specificity of LAMP were measured dependent on the concentration of DNA polymerase and the reaction temperature and time.In addition,to determine species-specific LAMP primers,cross reactivity testing was applied to the reaction between NVV and other virus families including viral hemorrhagic septicemia virus and marine birnavirus.Results:The optimized LAMP reaction carried out at 64 ℃ for 60 min,and above 4 U Bst DNA polymerase.The sensitivity of LAMP for the detection of nnv was thus about 10 times greater than the sensitivity of polymerase chain reaction.The LAMP assay primers were specific for the detection NNV infection in Epinephelus septemfasciatus.Conclusions:The development of LAMP primers based on genetic information from a public database,not virus-infected samples,may provide a very simple and convenient method to identify viral infection in aquatic organisms.展开更多
Loop-mediated isothermal amplification(LAMP)is a novel nucleic acid amplification method.Compared with the widely utilized polymerase chain reaction(PCR),LAMP has higher speed and efficiency as well as lower requireme...Loop-mediated isothermal amplification(LAMP)is a novel nucleic acid amplification method.Compared with the widely utilized polymerase chain reaction(PCR),LAMP has higher speed and efficiency as well as lower requirement for system temperature control because the whole amplification process is isothermal and no efforts are needed to switch between different temperatures.In this paper,we designed and fabricated different kinds of polycarbonate(PC)microfluid chips,explored appropriate reaction condition for LAMP in microenvironment(1 nL→10μL),and developed a microfluidic isothermal amplification detection system.The DNA optimal amplification temperature is obtained;the starting time of exponential amplification of DNA is put forward farther.The optimal condition of DNA amplification in microenvironment,with a little reaction materials and early starting exponential amplification time of DNA are very important for clinic DNA detection and the application of Lab-on-a-Chip.展开更多
Dendrobium officinale is not only an ornamental plant, but also a valuable medicinal herb that is widely used in traditional Chinese medicine. However, distinguishing D. officinale from other Dendrobium species is usu...Dendrobium officinale is not only an ornamental plant, but also a valuable medicinal herb that is widely used in traditional Chinese medicine. However, distinguishing D. officinale from other Dendrobium species is usually a difficult task. In this study,we developed a rapid identification protocol for D. officinale using the loop-mediated isothermal amplification(LAMP) method. A set of primers were specifically designed to detect a modified internal transcribed spacer region of D. officinale at 65 ℃ within 40 min after adding SYBR~? Green I, which was used for the detection of D. officinale. Unlike commonly used adulterants, reaction mixtures containing D. officinale DNA changed from orange to green, and this color change was easily observed with the naked eye. Thus, this methodology can be used to accurately differentiate D. officinale from other Dendrobium species, is quick as all D. officinale samples were amplified within 40 min, and specific as samples of the adulterants were not amplified. The specificity of this LAMP-based method was confirmed by testing 17 samples of D. officinale and 32 adulterant samples from other Dendrobium species. This LAMP-based rapid identification method does not require expensive equipment or specialized techniques and can be used in field surveys for accurate and fast on-site identification.展开更多
Background:Helminths are endemic in more than half of the world's countries,raising serious public health concerns.Accurate diagnosis of helminth infection is crucial to control strategies.Traditional parasitologi...Background:Helminths are endemic in more than half of the world's countries,raising serious public health concerns.Accurate diagnosis of helminth infection is crucial to control strategies.Traditional parasitological methods,serological tests and PCR-based assays are the major means of the diagnosis of helminth infeaion,but they are time-consuming and/or expensive,and sometimes provide inaccurate results.Loop mediated isothermal amplification(LAMP)assay,a sensitive,simple and rapid method was therefore developed for deteaion of helminths.This study aims to discuss the current status of application of LAMP on helminths detection and to make a comprehensive evaluation about this updated technology and its future outlook by comparing with several other diagnostic methods.Main body:This review summarizes LAMP assay applied for helminth detection and helminthiasis surveillance.The basic principle of LAMP is introduced to help better understand its characteristics and each reported assay is assessed mainly based on its detection sensitivity,specificity and limitations,in comparison with other common diagnostic tests.Moreover,we discuss the limitations of the assays so as to clarify some potential ways of improvement.Conclusions:Here,we summarize and discuss the advantages,disadvantages and promising future of LAMP in heliminth detection,which is expected to help update current knowledge and future perspectives of LAMP in highly sensitive and specific diagnosis and surveillance of helminthiasis and other parasitic diseases,and can contribute to the elimination of the diseases from endemic areas.展开更多
Pseudomonas aeruginosa(PA)is an opportunistic pathogen of humans and animals and a common source of nosocomial infections especially of the respiratory tract.Pseudomonas aeruginosa is also a major bacterial disease of...Pseudomonas aeruginosa(PA)is an opportunistic pathogen of humans and animals and a common source of nosocomial infections especially of the respiratory tract.Pseudomonas aeruginosa is also a major bacterial disease of poultry and in particular,eggs and newly hatched chicks.In this study,we developed a simple,accurate and rapid molecular detection method using cross priming amplification(CPA)with a nucleic acid test strip to detect P.aeruginosa.The assay efficiently amplified the target gene within 45 min at 62℃only using a simple water bath.The detection limit of the method was 1.18x 102 copiesμL^-1 for plasmid DNA and 4.4 CFU mL^-1 for bacteria in pure culture,and was 100 times more sensitive than conventional PCR.We screened 83 clinical samples from yellow-feather broiler breeder chickens and hospitalized/treated dogs and cats using CPA,PCR and traditional culture methods.The positive sample ratios were 15.3%(13/83)by CPA,13.3%(11/83)by PCR and 12.1%(10/83)by the culture method.The established CPA method has significant advantages for detecting P.aeruginosa.The method is easy to use and possesses high specificity and sensitivity without the requirements of complicated experimental equipment.The PA-CPA assay is especially fit for outdoor and primary medical units and is an ideal system for the rapid detection and monitoring of P.aeruginosa.展开更多
With the increasing global threat of various diseases and infections,it is essential to develop a fast,low-cost,and easy-to-use point-of-care testing(POCT)system for inspections at all levels of medical institutions a...With the increasing global threat of various diseases and infections,it is essential to develop a fast,low-cost,and easy-to-use point-of-care testing(POCT)system for inspections at all levels of medical institutions and self-examination at home.In this work,gold magnetic nanoparticles(GMNPs)are used as the key material,and a rapid visual detection method is designed through integrating loop-mediated isothermal amplification(LAMP)and lateral flow assay(LFA)biosensor for detecting a variety of analytes which includes whole blood,buccal swabs,and DNA.It is worth to note that the proposed method does not need DNA extraction.Furthermore,uracil DNA glycosylase(UDG)is employed to eliminate carrier contamination for preventing false positive results.The whole detection process can be finished within 25 min.The accuracy of detection is measured by assessing the polymorphisms of the methylenetetrahydrofolate reductase(MTHFR)C677T.The detection limit of the newly developed extraction-free detection system for MTHFR C677T is 0.16 ng/μL.A preliminary clinical study of the proposed method is carried out by analyzing 600 clinical samples(including 200 whole blood samples,100 buccal swabs,and 300 genomic DNA samples).The results indicate that the proposed method is 100%consistent with the sequencing results which provides a new choice for POCT and shows a broad application prospect in all levels of medical clinics and at home.展开更多
基金Supported by the Natural Science Foundation of Heilongjiang Province(Topic C2017032)Heilongjiang Province Applied Technology Research and Development Program(Topic GA19B104)the National Key Research and Development Program(Topic 2018YFD0300105)。
文摘Rice bacterial leaf brown spot disease caused by Pseudomonas syringae pv.syringae(Pss)is a major disease on rice.In recent years,Pss has emerged worldwide,seriously affecting rice production.It is very important to establish a rapid detection method of Pss for the diagnosis and prevention of this disease.In order to robust and accurately diagnose the rice bacterial leaf brown spot disease in the field and laboratory,an assay system for the Pss was developed in this study,and the specific sequence of hrcN was used as the target,based on loop-mediated isothermal amplification(LAMP).The best detection system was MgSO 48 mmol·L^(-1),Bst DNA polymerase 8 U,dNTP 1.4 mmol·L^(-1),the ratio of internal and outer primers was 2:1,the reaction temperature was 63℃,the reaction time was 45 min,and the lowest sensitivity was 104 CFU·mL^(-1).This results provided an accurate and robust method for laboratory and field diagnosis of bacterial leaf brown spot disease of rice.
基金supported by Independent Innovation Specific Projects of Shandong Province ( 2008ZHZX1A1103)
文摘[Objective] To develop a rapid and visualized detection method using loop-mediated isothermal amplification (LAMP), improve the detection rate of canine parvovirus (CPV) and reduce the testing cost. [Method] According to the conserved regions of the VP2 gene of CPV, six primers were designed to amplify the special DNA sequences by LAMP. In addition, the reaction conditions of LAMP were optimized, and the sensitivity, specificity, repeatability and stability were verified. [Result] The optimal reaction time of the LAMP method for CPV was 60 min. The products obtained by LAMP had high specificity without cross-reaction with other generic viruses. The sensitivity of the LAMP was 100 times higher than that of PCR. [Conclusion] The LAMP method for detecting CPV has high practical value. It has many advantages such as high specificity, high sensitivity, simple operation, low cost and rapid analysis, and it does not require special equipment. Therefore, this method is more suitable for the detection of CPV.
基金supported financially by a research grant from the Natural Sciences Research Institute,University of the Philippines ) BIO 1 l-l-05) to W.L.R.
文摘Objective:To develop a loop-mediated isothermal amplification(LAMP) assay for the detection of Entamoeba histolytica(E.histolytica),the causative agent of amebiasis.Methods:The LAMP primer set was designed from E.histolytica hemolysin gene HLY6.Genomic DNA of E.histolytica trophozoites strain HK9 was used to optimize the LAMP mixture and conditions.Amplification of DNA in the LAMP mixture was monitored through visual inspection for turbidity of the LAMP mix as well as addition of fluorescent dye.Results:Positive LAMP reactions turned turbid while negative ones remained clear.Upon addition of a fluorescent dye,all positive reactions turned green while the negative control remained orange under ambient light After elecrophoresis in 1.5% agarose gels,a ladder of multiple bands of different sizes can be oliserved in positive samples while no bands were detected in the negative control.The sensitivity of the assay was found to be S parasites per reaction which corresponds to approximately 1S.8 ng/μL DNA.The specificity of the assay was verified by the absence of amplified products when DNA from other gastrointestinal parasites such as the morphologically similar but non-pathogenic species,Entamoeba dispar. and other diarrhea-causing organisms such as Blastocystis hominis and Escherichia coli were used.Conclusions:The I.AMP assay we have developed enables the detection of E.histolytica with rapidity and ease,therefore rendering it is suitable for laboratory and field diagnosis of amebiasis.
基金the earmarked fund for Beijing Innovation Consortium of Agriculture Research System(Grant No.BAIC-2019)Key Laboratory of Biology and Genetic Improvement of Horticultural Crops,Ministry of Agriculture,P.R.China,and Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(Grant No.CAAS-ASTIPIVFCAAS).
文摘Pectobacterium carotovorum is the causal agent of bacterial soft rot in a wide range of vegetable host species.Once P.carotovorum infects the plant,the spread of the disease is difficult to control.In this study,a rapid and sensitive method based on loop-mediated isothermal amplification(LAMP)was developed for detecting P.carotovorum in celery with soft rot using a primer set designed from the pmrA conserved sequence of P.carotovorum.The specificity of the LAMP primer set for P.carotovorum was extensively validated on both P.carotovorum strains and nontarget strains.The sensitivity was 1 pg of P.carotovorum genomic DNA,which demonstrated 10 times more sensitive than the conventional PCR assay.LAMP was also used to detect P.carotovorum in bacterial suspension.The lowest detection concentration was 104 CFU·mL^−1.In addition,a LAMP assay,in conjunction with a crude DNA extraction method,was successfully performed on P.carotovorum-infected samples derived from both artificially and naturally infected plants.In summary,the LAMP assay established in this study constitutes a simple,sensitive,and rapid method for the detection of P.carotovorum,and has potential application in the control of celery soft rot disease through early detection.
文摘A sensitive reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for human enterovirus 71 (EV71) and Coxsackievirus A16 (CVA16) infection was further evaluated. The one step reaction was performed in a single tube at 65?C for 45 min for EV71 and 35 min for CVA16. The detection limits of RT-LAMP assays for both EV71 and CVA16 were 0.1 of a 50% tissue culture infective dose (TCID50) per reaction, based on 10—Fold dilutions of a titrated EV71 or CVA16 strain. The specific assay showed there were no cross-reactions with Coxsackievirus A (CVA) viruses (CVA 2, 4, 5, 7, 9, 10, 14, and 25), Coxsackievirus B (CVB) viruses (CVB 1, 2, 3, 4, and 5) or ECHO viruses (ECHO 3, 6, 11, and 19). In parallel with commercial quantitative real-time polymerase chain reaction (qRT-PCR) diagnostic kits for EV71 and CVA16, the RT-LAMP assay was evaluated with 515 clinical specimens, the results showed the RT-LAMP assay and the qRT-PCR assay were in complete agreement for 513/515 (99.6%) of the specimens. Two samples with discrepant results from two methods were further verified by nested reverse transcription polymerase chain reaction (nRT-PCR) assay and sequencing to be true positives for CVA16. In conclusion, RT-LAMP assay is demonstrated to be a sensitive and specific assay and have a great potential for the rapid and visual screening of EV71 and CVA16 in China, especially in those resource-limited hospitals and rural clinics of provincial and municipal regions.
文摘Plague caused by Yersinia pestis is one of the infectious diseases subject to the International Health Regulations (IHR). Permanent monitoring of the focal plague areas is mandatory in order to enable prompt control measures to prevent the spread of the disease. Therefore, the availability of efficient diagnosis tests is of paramount importance. Here, we describe a loop-mediated isothermal amplification (LAMP)-based procedure for rapid Y. pestis detection. We constructed a set of LAMP primers, which were used in assays to establish the reaction conditions that would lead to the quick visualization of the results by evaluating the test tube with the naked eye. The primers were specifically designed to target the caf1 gene located on pFra/Tox (pMT), a prototypical plasmid of Y. pestis. The LAMP procedure was performed at 65°C for 45 min in a water bath and allowed for the detection of at least 10 pg of bacterial DNA. Due to its simplicity, specificity, sensitivity and rapidity, the LAMP technique is an additional tool that may be implemented in routine plague diagnoses, especially in emergencies.
基金the Science and Technology Joint Project of the Yangtze River Delta (19395810100)Shanghai Agriculture Project (19391901500)+2 种基金the National Key Research and Development Program of China (2016YFD0501101)the Shanghai Science and Technology Innovation Foundation (19441903900 and 19XD1433000)Project of National Natural Science Foundation of China (82003705)。
文摘The rapid and accurate detection of peanuts and soybeans allergen is important to the food safety. In this study, Cu-TCPP nanosheet, a kind of ultra-thin metal-organic framework(MOF)was synthesized and applied in loop-mediated isothermal amplification(named Cu-TCPP@LAMP), which can inhibit the non-specific amplification by absorbing and precise temperature releasing of single primer. As thus, Cu-TCPP@LAMP can achieve high sensitivity and specific amplification of the target gene. As a result, peanut and soybean allergens genes contained in food were successfully detected with a favorable detection sensitivity(5 ng/μL for peanuts and 10 ng/μL for soybeans)and reliable repeatability(The coefficient of variation was 3.38% for peanuts and 3.33% for soybeans). Moreover, the established method was utilized for detection of several commercial products, and had a high consistency with the standard method. Apart from food allergens, this novel assay can be widely used in other areas, such as pathogen detection, tumor nucleic acid detection and so on.
文摘When the loop-mediated isothermal amplification(LAMP)assay is used for detecting target genes,DNA extraction is unnecessary in many cases.Simple pretreatment(e.g.heating)is enough to obtain rather sensitive responses.Even test samples without any pretreatment can be used as template.This feature suggests that LAMP is superior to PCR in developing point-of-care test strategies.In this study,using Stx1 gene from E.coli as model,we verified that viable cells,dead cells and extracellular DNA could function as template in the LAMP assay.In the incubation at 63℃,viable bacteria in the LAMP reaction mixture lysed completely within 2 min,providing DNA template for nucleic acid amplification.The Stx1 gene in diluted culture medium,spiked tap water,spiked seawater and real seawater all could be detected,with or without the step of DNA extraction.We found that the complex substances in real sample(e.g.natural seawater)exhibited considerable inhibitory effect on the sensitivity of the LAMP assay.These outcomes are meaningful for building a point-of-care strategy by employing the LAMP assay for environmental monitoring,bio-resource surveys,food safety,etc.in particular those based on environmental DNA.
基金This work was supported by the National Key Research and Development Program of China(2019YFC1606300)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01S174)the Guangdong Academy of Sciences Special Project of Implementing Innovation-Driven Development Capacity Building(2018GDASCX-0401).
文摘Rapid,sensitive,point-of-care detection of pathogenic bacteria is important for food safety.In this study,we developed a novel quantum dot nanobeads-labelled lateral flow immunoassay strip(QBs-labelled LFIAS)combined with strand displacement loop-mediated isothermal amplification(SD-LAMP)for quantitative Salmonella Typhimurium(ST)detection.Quantum dot nanobeads(QBs)served as fluorescence reporters,providing good detection efficiency.The customizable strand displacement(SD)probe was used in LAMP to improve the specificity of the method and prevent by-product capture.Detection was based on a sandwich immunoassay.A fluorescence strip reader measured the fluorescence intensity(FI)of the test(T)line and control(C)line.The linear detection range of the strip was 10^(2)–10^(8) colony forming units(CFU)·mL^(-1).The visual limit of detection was 10^(3) CFU·mL^(-1),indicating that the system was ten-fold more sensitive than AuNPs-labelled test strips.ST specificity was analyzed in accordance with agarose gel outputs of polymerase chain reaction(PCR)and SD-LAMP.We detected ST in foods with an acceptable recovery of 85%–110%.The method is rapid,simple,almost equipment-free,and suitable for bacterial detection in foods and for clinical diagnosis.
基金This work was funded by Major Scientific and Technological Project of Xinjiang Corps(Grant No.2019AA004)China Agriculture Research System(Grant No.CARS-27).
文摘Apple bitter rot is a serious agricultural disease caused by Colletotrichum gloeosporioides.In recent years,carbendazim-resistant C.gloeosporioides strains bearing an E198A point mutation in theβ-tubulin gene(GAG to GCG)have emerged,threatening global apple production.As such,rapidly detecting the presence of this E198Amutation in C.gloeosporioides isolates is essential in order to monitor the spread of this pathogen and to prevent outbreaks of disease.Herein,we developed a simple loop-mediated isothermal amplification(LAMP)approach to detecting the E198A mutation in C.gloeosporioides isolates from‘Gala’apple samples.This optimized LAMP protocol was sufficient to establish the E198A genotype of a given isolate following a 60min incubation at 63℃ by using four specific primers.The results of this reaction could be interpreted visually based on a fluorescent yellow-green color change upon the addition of the SYBR Green I dye,and were additionally confirmed via gel electrophoresis.Importantly,this LAMP assay was capable of rapidly and reliably detecting apples that were infected with carbendazim-resistant isolates harboring this E198A mutation.In conclusion,this LAMP assay in this study can rapidly,specifically,and sensitively detect cases of apple bitter rot caused by C.gloeosporioides isolates harboring the E198A mutation.
基金the financial support provided by project of Science and Technology Tackling Key Problems in Henan Province(Grant No.182102110430)the National Key Research and Development Program of China(Grant No.2016YFD0101300)by China Agricultural Research system(CARS-12).
文摘In the last decade,some disease occurred on our experimental farms that had caused serious losses.They were not caused by fungi,bacteria or viruses.By loop-mediated isothermal amplification(LAMP)technique,the detection results pointed to the possible pathogen as phytoplasma.The investigation results implied that phytoplasmas could cause more than 13 kinds of symptoms in almost all parts of plants in B.napus L.,including witches’broom,multi-stems,aggregate main inflorescences,and flat stems.The incidences of these phytoplasma-associated diseases in our experimental farms rose from 1.61%in 2010 to 6.00%in 2021.Some phytoplasma infected plants died without any growing points.These studies would be helpful for detecting phytoplasmas diseases,selecting disease resistant germplasm and improving varieties with disease resistances in B.napus L.
文摘[Objectives]Loop-mediated isothermal amplification(LAMP)was developed and optimized for rapid and specific diagnosis of Brucella infection.[Methods]The conserved sequence of the brucellosis standard strain Omp25 gene fragment was selected,primers needed in the loop-mediated isothermal amplification system were designed,and nucleic acid of the standard strain was extracted.Primers,reaction system,reaction conditions and stain types were repeatedly optimized to establish an improved LAMP detection kit for brucellosis.Confirmatory tests were performed on blood samples from clinically confirmed cases and their sensitivity and specificity were confirmed.Then,the detection technology and kit were applied to the detection and screening of suspected B.melitensis in pastoral areas.Finally,SPSS21.0 was used to evaluate the consistency of LAMP and Q-PCR.[Results]LAMP system was optimized,and the optimal final concentrations of MgSO_(4) and betaine were 8 and 0.8 mmol/L,respectively.The sensitivity and specificity of the modified LAMP technique were verified by using human blood samples with confirmed brucellosis.In LAMP specific test,there was no nonspecific amplification,indicating good specificity.In the LAMP sensitivity test,the minimum detection line for B.melitensis,B.abortus,and B.suis was 10 copies/μL,which was an order of magnitude higher than that for Q-PCR.The consistency between modified LAMP and Q-PCR was 0.941.The established Brucella LAMP kit was used to detect the blood samples of 200 sheep suspected to be infected with Brucella.The LAMP kit detected 42 positive samples,with a positive rate of 21%and a detection sensitivity of 100%.Negative specimens were detected in 158 cases,with a specificity of 100%.There were 41 negative samples detected by PCR,with a positive rate of 20.5%.The detection specificity was consistent with that of LAMP kit.[Conclusions]The modified LAMP for Brucella has been successfully established.This technology is characterized by good sensitivity and specificity,low cost and high efficiency,and is conducive to the development in primary medical institutions.
基金supported by grants from Jiangsu Higher Education Institution Innovative Research Team for Science and Technology(2021),the Key Technology Program of Suzhou People’s Livelihood Technology Projects(Grant Nos.SKY2021029,SZS2020311)the Open Project of Jiangsu Biobank of Clinical Resources(TC2021B009)the Qing-Lan Project of Jiangsu Province in China(2021,2022).
文摘Nucleic acid(DNA and RNA)detection and quantification methods play vital roles in molecular biology.With the development of molecular biology,isothermal amplification of DNA/RNA,as a new molecular biology technology,can be amplified under isothermal condition,it has the advantages of high sensitivity,high specificity,and high efficiency,and has been applied in various fields of biotechnology,including disease diagnosis,pathogen detection,food hygiene and safety detection and so on.This paper introduces the progress of isothermal amplification technology,including rolling circle amplification(RCA),nucleic acid sequence-dependent amplification(NASBA),strand displacement amplification(SDA),loop-mediated isothermal amplification(LAMP),helicase-dependent amplification(HDA),recombinase polymerase amplification(RPA),cross-priming amplification(CPA),and its principle,advantages and disadvantages,and application development are briefly summarized.
基金supported by the Korea Institute of Ocean Science&Technology(No.PE99315)
文摘Objective:To establish a novel and highly specific loop-mediated isothermal amplification(LAMP) assay for the identification of nervous necrosis virus(NNV) infection.Methods:A set of synthesized primers was used to match the sequences of a specific region of the nnr gene from the National Center for Biotechnology Information database,not originating from NNV-infected fish,the efficiency and specificity of LAMP were measured dependent on the concentration of DNA polymerase and the reaction temperature and time.In addition,to determine species-specific LAMP primers,cross reactivity testing was applied to the reaction between NVV and other virus families including viral hemorrhagic septicemia virus and marine birnavirus.Results:The optimized LAMP reaction carried out at 64 ℃ for 60 min,and above 4 U Bst DNA polymerase.The sensitivity of LAMP for the detection of nnv was thus about 10 times greater than the sensitivity of polymerase chain reaction.The LAMP assay primers were specific for the detection NNV infection in Epinephelus septemfasciatus.Conclusions:The development of LAMP primers based on genetic information from a public database,not virus-infected samples,may provide a very simple and convenient method to identify viral infection in aquatic organisms.
基金supported by the National Foundation of High Technology of China(2006AA020701 and 2006AA020803)National Program on Key Basic Research Projects 973 of China(2006CB705700)+1 种基金the Nature Science Foundation of Zhejiang Province(2006C21G3210005)Tsinghua-Yuyuan Medicine Foundation(40000510B).
文摘Loop-mediated isothermal amplification(LAMP)is a novel nucleic acid amplification method.Compared with the widely utilized polymerase chain reaction(PCR),LAMP has higher speed and efficiency as well as lower requirement for system temperature control because the whole amplification process is isothermal and no efforts are needed to switch between different temperatures.In this paper,we designed and fabricated different kinds of polycarbonate(PC)microfluid chips,explored appropriate reaction condition for LAMP in microenvironment(1 nL→10μL),and developed a microfluidic isothermal amplification detection system.The DNA optimal amplification temperature is obtained;the starting time of exponential amplification of DNA is put forward farther.The optimal condition of DNA amplification in microenvironment,with a little reaction materials and early starting exponential amplification time of DNA are very important for clinic DNA detection and the application of Lab-on-a-Chip.
基金supported by the Opening Project of State Key Laboratory of Quality Research in Chinese Medicine(Macao University of Science and Technology)(No.MUST-SKL-2016-07)the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.201710572024)
文摘Dendrobium officinale is not only an ornamental plant, but also a valuable medicinal herb that is widely used in traditional Chinese medicine. However, distinguishing D. officinale from other Dendrobium species is usually a difficult task. In this study,we developed a rapid identification protocol for D. officinale using the loop-mediated isothermal amplification(LAMP) method. A set of primers were specifically designed to detect a modified internal transcribed spacer region of D. officinale at 65 ℃ within 40 min after adding SYBR~? Green I, which was used for the detection of D. officinale. Unlike commonly used adulterants, reaction mixtures containing D. officinale DNA changed from orange to green, and this color change was easily observed with the naked eye. Thus, this methodology can be used to accurately differentiate D. officinale from other Dendrobium species, is quick as all D. officinale samples were amplified within 40 min, and specific as samples of the adulterants were not amplified. The specificity of this LAMP-based method was confirmed by testing 17 samples of D. officinale and 32 adulterant samples from other Dendrobium species. This LAMP-based rapid identification method does not require expensive equipment or specialized techniques and can be used in field surveys for accurate and fast on-site identification.
文摘Background:Helminths are endemic in more than half of the world's countries,raising serious public health concerns.Accurate diagnosis of helminth infection is crucial to control strategies.Traditional parasitological methods,serological tests and PCR-based assays are the major means of the diagnosis of helminth infeaion,but they are time-consuming and/or expensive,and sometimes provide inaccurate results.Loop mediated isothermal amplification(LAMP)assay,a sensitive,simple and rapid method was therefore developed for deteaion of helminths.This study aims to discuss the current status of application of LAMP on helminths detection and to make a comprehensive evaluation about this updated technology and its future outlook by comparing with several other diagnostic methods.Main body:This review summarizes LAMP assay applied for helminth detection and helminthiasis surveillance.The basic principle of LAMP is introduced to help better understand its characteristics and each reported assay is assessed mainly based on its detection sensitivity,specificity and limitations,in comparison with other common diagnostic tests.Moreover,we discuss the limitations of the assays so as to clarify some potential ways of improvement.Conclusions:Here,we summarize and discuss the advantages,disadvantages and promising future of LAMP in heliminth detection,which is expected to help update current knowledge and future perspectives of LAMP in highly sensitive and specific diagnosis and surveillance of helminthiasis and other parasitic diseases,and can contribute to the elimination of the diseases from endemic areas.
基金Supported by the Guangdong Key S&T Program(2019B020217002)from the Department of Science and Technology of Guangdong Province,China,the Guangdong Poultry Industry Technology System,China(2019KJ128)the earmarked fund for China Agriculture Research System(CARS-41-G16).
文摘Pseudomonas aeruginosa(PA)is an opportunistic pathogen of humans and animals and a common source of nosocomial infections especially of the respiratory tract.Pseudomonas aeruginosa is also a major bacterial disease of poultry and in particular,eggs and newly hatched chicks.In this study,we developed a simple,accurate and rapid molecular detection method using cross priming amplification(CPA)with a nucleic acid test strip to detect P.aeruginosa.The assay efficiently amplified the target gene within 45 min at 62℃only using a simple water bath.The detection limit of the method was 1.18x 102 copiesμL^-1 for plasmid DNA and 4.4 CFU mL^-1 for bacteria in pure culture,and was 100 times more sensitive than conventional PCR.We screened 83 clinical samples from yellow-feather broiler breeder chickens and hospitalized/treated dogs and cats using CPA,PCR and traditional culture methods.The positive sample ratios were 15.3%(13/83)by CPA,13.3%(11/83)by PCR and 12.1%(10/83)by the culture method.The established CPA method has significant advantages for detecting P.aeruginosa.The method is easy to use and possesses high specificity and sensitivity without the requirements of complicated experimental equipment.The PA-CPA assay is especially fit for outdoor and primary medical units and is an ideal system for the rapid detection and monitoring of P.aeruginosa.
基金This work was supported by the National Natural Science Foundation of China(Nos.31771083 and 81772289).
文摘With the increasing global threat of various diseases and infections,it is essential to develop a fast,low-cost,and easy-to-use point-of-care testing(POCT)system for inspections at all levels of medical institutions and self-examination at home.In this work,gold magnetic nanoparticles(GMNPs)are used as the key material,and a rapid visual detection method is designed through integrating loop-mediated isothermal amplification(LAMP)and lateral flow assay(LFA)biosensor for detecting a variety of analytes which includes whole blood,buccal swabs,and DNA.It is worth to note that the proposed method does not need DNA extraction.Furthermore,uracil DNA glycosylase(UDG)is employed to eliminate carrier contamination for preventing false positive results.The whole detection process can be finished within 25 min.The accuracy of detection is measured by assessing the polymorphisms of the methylenetetrahydrofolate reductase(MTHFR)C677T.The detection limit of the newly developed extraction-free detection system for MTHFR C677T is 0.16 ng/μL.A preliminary clinical study of the proposed method is carried out by analyzing 600 clinical samples(including 200 whole blood samples,100 buccal swabs,and 300 genomic DNA samples).The results indicate that the proposed method is 100%consistent with the sequencing results which provides a new choice for POCT and shows a broad application prospect in all levels of medical clinics and at home.