Genetic lineage tracing has been widely employed to investigate cell lineages and fate.However,conventional reporting systems often label the entire cytoplasm,making it challenging to discern cell boundaries.Additiona...Genetic lineage tracing has been widely employed to investigate cell lineages and fate.However,conventional reporting systems often label the entire cytoplasm,making it challenging to discern cell boundaries.Additionally,single Cre-lox P recombination systems have limitations in tracing specific cell populations.This study proposes three reporting systems utilizing Cre,Dre,and Dre+Cre mediated recombination.These systems incorporate td Tomato expression on the cell membrane and Phi YFP expression within the nucleus,allowing for clear observation of the nucleus and membrane.The efficacy of these systems is successfully demonstrated by labeling cardiomyocytes and hepatocytes.The potential for dynamic visualization of the cell membrane is showcased using intravital imaging microscopy or threedimensional imaging.Furthermore,by combining this dual recombinase system with the Pro Tracer system,hepatocyte proliferation is traced with enhanced precision.This reporting system holds significant importance for advancing the understanding of cell fate studies in development,homeostasis,and diseases.展开更多
With the approval of more and more genetically modified(GM)crops in our country,GM safety management has become more important.Transgenic detection is a major approach for transgenic safety management.Nevertheless,a c...With the approval of more and more genetically modified(GM)crops in our country,GM safety management has become more important.Transgenic detection is a major approach for transgenic safety management.Nevertheless,a convenient and visual technique with low equipment requirements and high sensitivity for the field detection of GM plants is still lacking.On the basis of the existing recombinase polymerase amplification(RPA)technique,we developed a multiplex RPA(multi-RPA)method that can simultaneously detect three transgenic elements,including the cauliflower mosaic virus 35S gene(CaMV35S)promoter,neomycin phosphotransferaseⅡgene(NptⅡ)and hygromycin B phosphotransferase gene(Hyg),thus improving the detection rate.Moreover,we coupled this multi-RPA technique with the CRISPR/Cas12a reporter system,which enabled the detection results to be clearly observed by naked eyes under ultraviolet(UV)light(254 nm;which could be achieved by a portable UV flashlight),therefore establishing a multi-RPA visual detection technique.Compared with the traditional test strip detection method,this multi-RPA-CRISPR/Cas12a technique has the higher specificity,higher sensitivity,wider application range and lower cost.Compared with other polymerase chain reaction(PCR)techniques,it also has the advantages of low equipment requirements and visualization,making it a potentially feasible method for the field detection of GM plants.展开更多
Soil DNA extraction,such as microbial community analysis and gene drift detection,is an important basis for multiple analyses in different fields.Nevertheless,the soil DNA extraction methods for field detection are st...Soil DNA extraction,such as microbial community analysis and gene drift detection,is an important basis for multiple analyses in different fields.Nevertheless,the soil DNA extraction methods for field detection are still lacking.This study established a rapid soil DNA extraction(RSDE)method that can be used in field detection.In this method,we first utilized the optimized lysate to isolate DNA from soil and then used a filtration membrane and a DNA adsorption membrane to purify the DNA via the column method.Moreover,we used the pressure from the syringe instead of the conventional centrifugal force of the centrifuge to assist the sample filtration,resulting in very low requirements for this method,with an extraction time of less than 20 min.Furthermore,we demonstrated that the RSDE method was applicable for DNA extraction from different types of soils,with the demand for soil samples as low as 0.1 g and that the amount of obtained DNA was,to some extent,greater than that obtained by a commercial kit.Further analysis revealed that this extracted genomic DNA can be used directly for polymerase chain reaction(PCR)analysis,including ordinary PCR,real-time fluorescent quantitative PCR,and recombinase polymerase amplification(RPA)-CRISPR/Cas12a visual assays.In addition,we demonstrated that this method can be used to extract DNA from residual plant roots in addition to soil microbes,which lays a foundation for the comprehensive analysis of soil plants and microorganisms.In summary,the RSDE method proposed in this study may have wide application prospects.展开更多
Glugea plecoglossi,a microsporidia of the Glugea genus,can cause an infamous disease Plecoglossus altivelis in East Asia,resulting in heavy economic losses.At present,the main diagnostic methods for this disease inclu...Glugea plecoglossi,a microsporidia of the Glugea genus,can cause an infamous disease Plecoglossus altivelis in East Asia,resulting in heavy economic losses.At present,the main diagnostic methods for this disease include microscopy examination,quantitative real-time PCR,and loop-mediated isothermal amplification-lateral flow dipstick(LAMP-LFD).In this study,a recombinase polymerase amplification-lateral flow dipstick(RPA-LFD)method,targeting the beta-tubulin gene,was developed to detect G.plecoglossi,three sets of primers and probes were designed and screened,after which the initial reaction system was established.The RPA-LFD method for G.plecoglossi could complete nucleic acid amplification at 39℃ for 10 min,after which the amplification product was dropped on the LFD strip,and the results could then be observed within 5 min.A specificity assay revealed that there was no cross reactivity with other protozoa except G.plecoglossi.A sensitivity assay revealed that the detection limit was 9.38×10^(-6) ng/μL,which was more sensitive than that of conventional PCR.Compared with conventional detection methods,the novel RPA-LFD method has the advantages of simple operation,short operation time,high sensitivity,and high specificity for G.plecoglossi detection,indicating its potential use in rapid field detection of G.plecoglossi.展开更多
Human bocavirus(HBoV)1 is considered an important pathogen that mainly affects infants aged 6–24 months,but preventing viral transmission in resource-limited regions through rapid and affordable on-site diagnosis of ...Human bocavirus(HBoV)1 is considered an important pathogen that mainly affects infants aged 6–24 months,but preventing viral transmission in resource-limited regions through rapid and affordable on-site diagnosis of individuals with early infection of HBoV1 remains somewhat challenging.Herein,we present a novel faster,lower cost,reliable method for the detection of HBoV1,which integrates a recombinase polymerase amplification(RPA)assay with the CRISPR/Cas12a system,designated the RPA-Cas12a-fluorescence assay.The RPA-Cas12a-fluorescence system can specifically detect target gene levels as low as 0.5 copies of HBoV1 plasmid DNA per microliter within 40 min at 37℃without the need for sophisticated instruments.The method also demonstrates excellent specificity without cross-reactivity to non-target pathogens.Furthermore,the method was appraised using 28 clinical samples,and displayed high accuracy with positive and negative predictive agreement of 90.9%and 100%,respectively.Therefore,our proposed rapid and sensitive HBoV1 detection method,the RPA-Cas12a-fluorescence assay,shows promising potential for early on-site diagnosis of HBoV1 infection in the fields of public health and health care.The established RPA-Cas12a-fluorescence assay is rapid and reliable method for human bocavirus 1 detection.The RPA-Cas12a-fluorescence assay can be completed within 40 min with robust specificity and sensitivity of 0.5 copies/μl.展开更多
Traditional transgenic detection methods require high test conditions and struggle to be both sensitive and efficient.In this study,a one-tube dual recombinase polymerase amplification(RPA)reaction system for CP4-EPSP...Traditional transgenic detection methods require high test conditions and struggle to be both sensitive and efficient.In this study,a one-tube dual recombinase polymerase amplification(RPA)reaction system for CP4-EPSPS and Cry1Ab/Ac was proposed and combined with a lateral flow immunochromatographic assay,named“Dual-RPA-LFD”,to visualize the dual detection of genetically modified(GM)crops.In which,the herbicide tolerance gene CP4-EPSPS and the insect resistance gene Cry1Ab/Ac were selected as targets taking into account the current status of the most widespread application of insect resistance and herbicide tolerance traits and their stacked traits.Gradient diluted plasmids,transgenic standards,and actual samples were used as templates to conduct sensitivity,specificity,and practicality assays,respectively.The constructed method achieved the visual detection of plasmid at levels as low as 100 copies,demonstrating its high sensitivity.In addition,good applicability to transgenic samples was observed,with no cross-interference between two test lines and no influence from other genes.In conclusion,this strategy achieved the expected purpose of simultaneous detection of the two popular targets in GM crops within 20 min at 37°C in a rapid,equipmentfree field manner,providing a new alternative for rapid screening for transgenic assays in the field.展开更多
Genome editing is considered as the most widely used approach of the present era. It had become a basic need of the current micro and molecular biological experiments. Gene engineering finds its widespread application...Genome editing is considered as the most widely used approach of the present era. It had become a basic need of the current micro and molecular biological experiments. Gene engineering finds its widespread applications in medical, industry and agricultural sector. Unlike previous genetic engineering practices to insert or delete a part of genetic material at random place, genome editing allows the precise manipulation of DNA at a specific location. Zinc Finger Nucleases (ZFNs), Transcription Activator like Effector Nucleases (TALENs), Clustered Regularly Interspresed Short Palindromic repeats (CRISPR/Cas system) and meganucleases (recombinases) are the prime tools for editing an organism’s genome. Genome editing tools have an advantage to selectively delete or to integrate specific genes at specific loci. Use of recombinases for specifying site has further reduced time to integrate genes site specifically. Site specific gene stacking by the use of recombinases coupled with ZFNs, TALENs, or CRISPR/Cas genes have paved new pathways to target genes site specifically and to improve germplasm in lesser time than conventional breeding approaches.展开更多
Objective To establish an ultra-sensitive,ultra-fast,visible detection method for Vibrio parahaemolyticus(VP).Methods We established a new method for detecting the tdh and trh genes of VP using clustered regularly int...Objective To establish an ultra-sensitive,ultra-fast,visible detection method for Vibrio parahaemolyticus(VP).Methods We established a new method for detecting the tdh and trh genes of VP using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 12a(CRISPR/Cas12a)combined with recombinase polymerase amplification and visual detection(CRISPR/Cas12a-VD).Results CRISPR/Cas12a-VD accurately detected target DNA at concentrations as low as 10^(-18)M(single molecule detection)within 30 min without cross-reactivity against other bacteria.When detecting pure cultures of VP,the consistency of results reached 100%compared with real-time PCR.The method accurately analysed pure cultures and spiked shrimp samples at concentrations as low as 10^(2)CFU/g.Conclusion The novel CRISPR/Cas12a-VD method for detecting VP performed better than traditional detection methods,such as real-time PCR,and has great potential for preventing the spread of pathogens.展开更多
Hepatitis C virus(HCV)infection represents a significant health problem and represents a heavy load on some countries like Egypt in which about 20%of the total population are infected.Initial infection is usually asym...Hepatitis C virus(HCV)infection represents a significant health problem and represents a heavy load on some countries like Egypt in which about 20%of the total population are infected.Initial infection is usually asymptomatic and result in chronic hepatitis that give rise to complications including cirrhosis and hepatocellular carcinoma.The management of HCV infection should not only be focus on therapy,but also to screen carrier individuals in order to prevent transmission.In the present,molecular detection and quantification of HCV genome by real time polymerase chain reaction(PCR)represent the gold standard in HCV diagnosis and plays a crucial role in the management of therapeutic regimens.However,real time PCR is a complicated approach and of limited distribution.On the other hand,isothermal DNA amplification techniques have been developed and offer molecular diagnosis of infectious dieses at point-of-care.In this review we discuss recombinase polymerase amplification technique and illustrate its diagnostic value over both PCR and other isothermal amplification techniques.展开更多
To solve the problem of embryonic lethality in conventional gene knockouts, site-specific recombinase （SSR） systems （Cre-loxP, FIp-FRT, and φC31） have been used for tissue-specific gene knockout. With the combina...To solve the problem of embryonic lethality in conventional gene knockouts, site-specific recombinase （SSR） systems （Cre-loxP, FIp-FRT, and φC31） have been used for tissue-specific gene knockout. With the combination of an SSR system and inducible gene expression systems （tetracycline and tamoxifen）, stage-specific knockout and transgenic expression can be achieved. The application of this ＂SSR＋inducible＂ conditional tool to genomic manipulation can be extended in various ways. Alternatives to conditional gene targeting, such as conditional gene trapping, multipurpose conditional alleles, and conditional gene silencing, have been developed. SSR systems can also be used to construct precise disease models with point mutations and chromosomal abnormalities. With these exciting achievements, we are moving towards a new era in which the whole genome can be manipulated as we wish.展开更多
Astrocytes are the most abundant cell type in the central nervous system(CNS).They provide trophic support for neurons,modulate synaptic transmission and plasticity,and contribute to neuronal dysfunction.Many transgen...Astrocytes are the most abundant cell type in the central nervous system(CNS).They provide trophic support for neurons,modulate synaptic transmission and plasticity,and contribute to neuronal dysfunction.Many transgenic mouse lines have been generated to obtain astrocyte-specific expression of inducible Cre recombinase for functional studies;however,the expression patterns of inducible Cre recombinase in these lines have not been systematically characterized.We generated a new astrocyte-specific Aldh1 l1-CreER^(T2)knock-in mouse line and compared the expression pattern of Cre recombinase between this and five widely-used transgenic lines(hGfap-CreER^(T2)from The Jackson Laboratory and The Mutant Mouse Resource and Research Center,Glast-CreER^(T2),Cx30-CreER^(T2),and Fgfr3-iCreER^(T2))by crossing with Ai14 mice,which express tdTomato fluorescence following Cre-mediated recombination.In adult Aldh1 l1-CreER^(T2):Ai 14 transgenic mice,tdTomato was detected throughout the CNS,and five novel morphologicallydefined types of astrocyte were described.Among the six evaluated lines,the specificity of Cre-mediated recombination was highest when driven by Aldh1 l1 and lowest when driven by hGfap;in the latter mice,co-staining between tdTomato and NeuN was observed in the hippocampus and cortex.Notably,evident leakage was noted in Fgfr3-iCreER^(T2)mice,and the expression level of tdTomato was low in the thalamus when Cre recombinase expression was driven by Glast and in the capsular part of the central amygdaloid nucleus when driven by Cx30.Furthermore,tdTomato was clearly expressed in peripheral organs in four of the lines.Our results emphasize that the astrocyte-specific CreER^(T2)transgenic lines used in functional studies should be carefully selected.展开更多
African swine fever(ASF)is an infectious disease caused by African swine fever virus(ASFV)with clinical symptoms of high fever,hemorrhages and high mortality rate,posing a threat to the global swine industry and food ...African swine fever(ASF)is an infectious disease caused by African swine fever virus(ASFV)with clinical symptoms of high fever,hemorrhages and high mortality rate,posing a threat to the global swine industry and food security.Quarantine and control of ASFV is crucial for preventing swine industry from ASFV infection.In this study,a recombinase polymerase amplification(RPA)-CRISPR-based nucleic acid detection method was developed for diagnosing ASF.As a highly sensitive method,RPA-CRISPR can detect even a single copy of ASFV plasmid and genomic DNA by determining fluorescence signal induced by collateral cleavage of CRISPR-lw Cas13 a(previously known as C2c2)through quantitative real-time PCR(q PCR)and has the same or even higher sensitivity than the traditional q PCR method.A lateral flow strip was developed and used in combination with RPA-CRISPR for ASFV detection with the same level of sensitivity of Taq Man q PCR.Likewise,RPA-CRISPR is capable of distinguishing ASFV genomic DNA from viral DNA/RNA of other porcine viruses without any cross-reactivity.This diagnostic method is also available for diagnosing ASFV clinical DNA samples with coincidence rate of 100%for both ASFV positive and negative samples.RPA-CRISPR has great potential for clinical quarantine of ASFV in swine industry and food security.展开更多
Parietal cells are one of the largest epithelium cells of the mucous membrane of the stomach that secrete hydrochloric acid. To study the function of gastric parietal cells during gastric epithelium homeostasis, we ge...Parietal cells are one of the largest epithelium cells of the mucous membrane of the stomach that secrete hydrochloric acid. To study the function of gastric parietal cells during gastric epithelium homeostasis, we generated a transgenic mouse line, namely, Atp4b-Cre, in which the expression of Cre recombinase was controlled by a 1.0 kb promoter of mouse β-subunit of H^＋-, K^＋-ATPase gene （Atp4b）. In order to test the tissue distribution and excision activity of Cre recombinase in vivo, the Atp4b-Cre transgenic mice were bred with the reporter strain ROSA26 and a mouse strain that carries Smad4 conditional alleles （Smad4Ca/Co）. Multiple-tissue PCR of Atp4b-Cre;Smad4Co/＋ mice revealed that the recombination only happened in the stomach. As indicated by LacZ staining, ROSA26;Atp4b-Cre double transgenic mice showed efficient expression of Cre recombinase within the gastric parietal cells. These results showed that this Atp4b-Cre mouse line could be used as a powerful tool to achieve conditional gene knockout in gastric parietal cells.展开更多
creening of foodborne pathogens is important to prevent contaminated foods from their supply chains.n this study, a portable detection device was developed for rapid, sensitive and simple detection of viable almonella...creening of foodborne pathogens is important to prevent contaminated foods from their supply chains.n this study, a portable detection device was developed for rapid, sensitive and simple detection of viable almonella using a finger-actuated microfluidic chip and an improved recombinase aided amplification (RAA) assay. Improved propidium monoazide(PMAxx) was combined with RAA to enable this device to distinguish viable bacteria from dead ones. The modification of PMAxx into dead bacteria, the magnetic xtraction of nucleic acids from viable bacteria and the RAA detection of extracted nucleic acids were performed using the microfluidic chip on its supporting device by finger press-release operations. The fluorescent signal resulting from RAA amplification of the nucleic acids was collected using a USB camera nd analyzed using a self-developed smartphone App to quantitatively determine the bacterial concenration. This device could detect Salmonella typhimurium in spiked chicken meats from 1.3 × 10^(2) CFU/m L o 1.3 × 10^(7) CFU/m L in 2 h with a lower detection limit of 130 CFU/m L, and has shown its potential for on-site detection of foodborne pathogens.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 sensitive,simple and rapid detection method for African swine fever virus(ASFV)B646L gene.Methods A recombinase-aided amplification-lateral flow dipstick(RAA-LFD)assay was developed in this st...Objective To establish a sensitive,simple and rapid detection method for African swine fever virus(ASFV)B646L gene.Methods A recombinase-aided amplification-lateral flow dipstick(RAA-LFD)assay was developed in this study.Recombinase-aided amplification(RAA)is used to amplify template DNA,and lateral flow dipstick(LFD)is used to interpret the results after the amplification is completed.The lower limits of detection and specificity of the RAA assay were verified using recombinant plasmid and pathogenic nucleic acid.In addition,30 clinical samples were tested to evaluate the performance of the RAA assay.Results The RAA-LFD assay was completed within 15 min at 37°C,including 10 min for nucleic acid amplification and 5 minutes for LFD reading results.The detection limit of this assay was found to be 200 copies per reaction.And there was no cross-reactivity with other swine viruses.Conclusion A highly sensitive,specific,and simple RAA-LFD method was developed for the rapid detection of the ASFV.展开更多
Osteoblasts participate in bone formation, bone mineralization, osteoclast differentiation and many pathological processes. To study the function of genes in osteoblasts using Cre-LoxP system, we generated a mouse lin...Osteoblasts participate in bone formation, bone mineralization, osteoclast differentiation and many pathological processes. To study the function of genes in osteoblasts using Cre-LoxP system, we generated a mouse line expressing the Cre recombinase under the control of the rat Collagenlcd （Collα1） promoter （Collα1-Cre）. Two founders were identified by genomic PCR from 16 offsprings, and the integration efficiency is 12.5%. In order to determine the tissue distribution and the activity of Cre recombinase in the transgenic mice, the Coll αl-Cre transgenic mice were bred with the ROSA26 reporter strain and a mouse strain that carries Smad4 conditional alleles （Smad4^Co/Co）. Multiple tissue PCR of Collα1-Cre;Smad4^Co/＋ mice revealed the restricted Cre activity in bone tissues containing osteoblasts and tendon. LacZ staining in the Collα1-Cre;ROSA26 double transgenic mice revealed that the Cre recombinase began to express in the osteoblasts of calvaria at E14.5. Cre activity was observed in the osteoblasts and osteocytes of P10 double transgenic mice. All these data indicated that the Collα1-Cre transgenic mice could serve as a valuable tool for osteoblast lineage analysis and conditional gene knockout in osteoblasts.展开更多
BACKGROUND：Gene therapy for Parkinson＇s disease is being explored as an effective strategy to restore and protect the function of neuronal cells in the substantia nigra. Regulation of gene expression is necessary fo...BACKGROUND：Gene therapy for Parkinson＇s disease is being explored as an effective strategy to restore and protect the function of neuronal cells in the substantia nigra. Regulation of gene expression is necessary for gene therapy to avoid adverse effects due to excessive synthesis of transgene products.OBJECTIVE：Here we developed recombinant adeno-associated virus （AAV） as a viral vector-mediated gene regulation system based on Cre recombinase fused to the mutated ligand-binding domain of the estrogen receptor （CreERT2） ＋ inducing agent tamoxifen. Inducible Cre recombinase was used to reduce tyrosine hydroxylase gene expression and to prevent the excessive increase in dopamine.DESIGN, TIME AND SETTING：A genetic engineering in vitro comparative study and randomized controlled animal experiment. This study was conducted at the Gene Therapy Center, Jichi Medical School, Japan from June 2002 to June 2004.METHODS：To construct a recombinant AAV vector carrying a dopamine synthase gene. The tyrosine hydroxylase gene was inserted using a IoxP fragment that could be regulated by Cre recombinase. The recombinant AAV vector carrying the CreERT2 gene was co-transduced with HEK293 cells and the corpus striatum in a rat model of Parkinson＇s disease, with inducing agent tamoxifen to regulate gene expression.MAIN OUTCOME MEASURES：The levels of dopamine and aromatic L-amino acid decarboxylase （AADC） activity were detected in HEK293 cell medium and in the corpus striatum in a rat model of Parkinson＇s disease using high-performance liquid chromatography. Immunofluorescence double staining was used to observe tyrosine hydroxylase and Cre or AADC co-expression in HEK293 cell medium. Immunohistochemical staining was employed to observe tyrosine hydroxylase and AADC expression and behavioral changes were measured in Parkinson＇s rats.RESULTS：Transfected AAV-CreERT2 and AAV expressing dopamine synthesis enzymes could increase the synthesis of dopamine in HEK293 medium and Parkinson＇s rat striatum （P 〈 0.01） and improve the rotational behavior of Parkinson＇s rats. While tamoxifen markedly reduced overproduction of dopamine caused by cotransfection of viral vectors （P 〈 0.01）, but did not affect the expression and activity of AADC.CONCLUSION：The application of AAV vector-encoded tyrosine hydroxylase gene under the gene regulation system of Cre-ERT2〉, after tamoxifen treatment, can effectively control the generation of genetically modified products to reduce the production of excessive dopamine in vivo and in vitro. Therefore, this method can increase the safety of gene therapy.展开更多
Xanthomonas oryzae pv.oryzae(Xoo)is a widespread pathogen causing bacterial leaf blight(BLB)disease,devastating rice productivity in many cultivated areas of Thailand.A specific and simple method for Xoo detection is ...Xanthomonas oryzae pv.oryzae(Xoo)is a widespread pathogen causing bacterial leaf blight(BLB)disease,devastating rice productivity in many cultivated areas of Thailand.A specific and simple method for Xoo detection is required to improve surveillance of disease transmission and outbreak.This study developed a recombinase polymerase amplification(RPA)assay assisted with CRISPR-cas12a assay(RAC)for Xoo detection from bacterial cell suspension of infected rice samples without DNA extraction.The efficiency of the RAC system for Xoo detection using either Xoo80 or Xoo4009 locus was optimized to amplify and determine the sensitivity and specificity using a Xoo DNA template from bacterial cell suspension of infected rice samples without DNA extraction.The RAC system using the Xoo4009 locus gave a higher specificity than Xoo80 locus,because only Xoo species was amplified positive RPA product with fluorescence signal by cas12a digestion,which indicated no cross reactivity.Optimal RAC using the Xoo4009 locus enabled diagnosis of Xoo presence from both plant extracted samples of Xoo artificially inoculated rice leaves within 3 d post-inoculation without symptomatic BLB appearance,and Xoo naturally infected rice.Findings exhibited that RAC using the Xoo4009 locus offered sensitivity,specificity and simplicity for Xoo detection,with low intensities of Xoo-DNA(1×10^(3) copies/μL)and Xoo-cell(2.5×10^(3) cfu/mL).This developed RAC system showed significantly potential for Xoo detection at point-of-care application for early signs of BLB disease outbreak in rice fields.展开更多
Cre/LoxP site-specified recombination system is mainly used for excision,inversion and integration of target gene.Therefore,this system can be used for plant marker free genetic transformation,site-specific transgene ...Cre/LoxP site-specified recombination system is mainly used for excision,inversion and integration of target gene.Therefore,this system can be used for plant marker free genetic transformation,site-specific transgene expression and so on.However,the application of this system was limited due to its low expression and excision efficiency.In this study,an intron,which can enhance gene expression in plants,was inserted into Cre by using PCR method.And a modified Cre gene,named Crein,was obtained.This gene was ...展开更多
基金supported by the National Key Research&Development Program of China(2021YFA0805100,2023YFA1800700,2019YFA0110403,2019YFA0802000)the National Science Foundation of China(82088101,32370885,92368103,32370897)the Westlake Education Foundation,and the Benyuan Charity Fund,Research Funds of Hangzhou Institute for Advanced Study(2022ZZ01015 and B04006C01600515)。
文摘Genetic lineage tracing has been widely employed to investigate cell lineages and fate.However,conventional reporting systems often label the entire cytoplasm,making it challenging to discern cell boundaries.Additionally,single Cre-lox P recombination systems have limitations in tracing specific cell populations.This study proposes three reporting systems utilizing Cre,Dre,and Dre+Cre mediated recombination.These systems incorporate td Tomato expression on the cell membrane and Phi YFP expression within the nucleus,allowing for clear observation of the nucleus and membrane.The efficacy of these systems is successfully demonstrated by labeling cardiomyocytes and hepatocytes.The potential for dynamic visualization of the cell membrane is showcased using intravital imaging microscopy or threedimensional imaging.Furthermore,by combining this dual recombinase system with the Pro Tracer system,hepatocyte proliferation is traced with enhanced precision.This reporting system holds significant importance for advancing the understanding of cell fate studies in development,homeostasis,and diseases.
基金the Experimental Technology Research Project of Zhejiang University(SYB202138)National Natural Science Foundation of China(32000195)。
文摘With the approval of more and more genetically modified(GM)crops in our country,GM safety management has become more important.Transgenic detection is a major approach for transgenic safety management.Nevertheless,a convenient and visual technique with low equipment requirements and high sensitivity for the field detection of GM plants is still lacking.On the basis of the existing recombinase polymerase amplification(RPA)technique,we developed a multiplex RPA(multi-RPA)method that can simultaneously detect three transgenic elements,including the cauliflower mosaic virus 35S gene(CaMV35S)promoter,neomycin phosphotransferaseⅡgene(NptⅡ)and hygromycin B phosphotransferase gene(Hyg),thus improving the detection rate.Moreover,we coupled this multi-RPA technique with the CRISPR/Cas12a reporter system,which enabled the detection results to be clearly observed by naked eyes under ultraviolet(UV)light(254 nm;which could be achieved by a portable UV flashlight),therefore establishing a multi-RPA visual detection technique.Compared with the traditional test strip detection method,this multi-RPA-CRISPR/Cas12a technique has the higher specificity,higher sensitivity,wider application range and lower cost.Compared with other polymerase chain reaction(PCR)techniques,it also has the advantages of low equipment requirements and visualization,making it a potentially feasible method for the field detection of GM plants.
基金the Experimental Technology Research Project of Zhejiang University(SYB202138)National Natural Science Foundation of China(32000195).
文摘Soil DNA extraction,such as microbial community analysis and gene drift detection,is an important basis for multiple analyses in different fields.Nevertheless,the soil DNA extraction methods for field detection are still lacking.This study established a rapid soil DNA extraction(RSDE)method that can be used in field detection.In this method,we first utilized the optimized lysate to isolate DNA from soil and then used a filtration membrane and a DNA adsorption membrane to purify the DNA via the column method.Moreover,we used the pressure from the syringe instead of the conventional centrifugal force of the centrifuge to assist the sample filtration,resulting in very low requirements for this method,with an extraction time of less than 20 min.Furthermore,we demonstrated that the RSDE method was applicable for DNA extraction from different types of soils,with the demand for soil samples as low as 0.1 g and that the amount of obtained DNA was,to some extent,greater than that obtained by a commercial kit.Further analysis revealed that this extracted genomic DNA can be used directly for polymerase chain reaction(PCR)analysis,including ordinary PCR,real-time fluorescent quantitative PCR,and recombinase polymerase amplification(RPA)-CRISPR/Cas12a visual assays.In addition,we demonstrated that this method can be used to extract DNA from residual plant roots in addition to soil microbes,which lays a foundation for the comprehensive analysis of soil plants and microorganisms.In summary,the RSDE method proposed in this study may have wide application prospects.
基金Supported by the Visiting and Training Foundation of Teachers in Ordinary Undergraduate Universities of Shandong Province,the Qingdao Agricultural University Doctoral Start-Up Fund(No.6631122030)the Advanced Talents Foundation of QAU(No.6651118016)+2 种基金the Fish Innovation Team of Shandong Agriculture Research System(No.SDAIT12-06)the Shandong Engineering Research Center for Prevention and Control of Aquatic Animal Disease,the“First Class Fishery Discipline”Program[(2020)3]of Shandong Provincethe Key R&D Program(Soft Science Project)of Shandong Province,China(No.2023 RKY 06004)。
文摘Glugea plecoglossi,a microsporidia of the Glugea genus,can cause an infamous disease Plecoglossus altivelis in East Asia,resulting in heavy economic losses.At present,the main diagnostic methods for this disease include microscopy examination,quantitative real-time PCR,and loop-mediated isothermal amplification-lateral flow dipstick(LAMP-LFD).In this study,a recombinase polymerase amplification-lateral flow dipstick(RPA-LFD)method,targeting the beta-tubulin gene,was developed to detect G.plecoglossi,three sets of primers and probes were designed and screened,after which the initial reaction system was established.The RPA-LFD method for G.plecoglossi could complete nucleic acid amplification at 39℃ for 10 min,after which the amplification product was dropped on the LFD strip,and the results could then be observed within 5 min.A specificity assay revealed that there was no cross reactivity with other protozoa except G.plecoglossi.A sensitivity assay revealed that the detection limit was 9.38×10^(-6) ng/μL,which was more sensitive than that of conventional PCR.Compared with conventional detection methods,the novel RPA-LFD method has the advantages of simple operation,short operation time,high sensitivity,and high specificity for G.plecoglossi detection,indicating its potential use in rapid field detection of G.plecoglossi.
基金Natural Science Foundation of ChinaGrant/Award Number:81973531+9 种基金Science and Technology Plan Project of Xi’anGrant/Award Number:22GXFW0007Shenzhen Science and Technology Innovation CommissionGrant/Award Number:20200812211704001Medical Scientific Research Foundation of Guangdong ProvinceGrant/Award Number:A2019502Nanshan District Science and Technology Plan ProjectGrant/Award Number:NS2022022Scientific Research Program Funded by Shaanxi Provincial Education DepartmentGrant/Award Number:22JC010
文摘Human bocavirus(HBoV)1 is considered an important pathogen that mainly affects infants aged 6–24 months,but preventing viral transmission in resource-limited regions through rapid and affordable on-site diagnosis of individuals with early infection of HBoV1 remains somewhat challenging.Herein,we present a novel faster,lower cost,reliable method for the detection of HBoV1,which integrates a recombinase polymerase amplification(RPA)assay with the CRISPR/Cas12a system,designated the RPA-Cas12a-fluorescence assay.The RPA-Cas12a-fluorescence system can specifically detect target gene levels as low as 0.5 copies of HBoV1 plasmid DNA per microliter within 40 min at 37℃without the need for sophisticated instruments.The method also demonstrates excellent specificity without cross-reactivity to non-target pathogens.Furthermore,the method was appraised using 28 clinical samples,and displayed high accuracy with positive and negative predictive agreement of 90.9%and 100%,respectively.Therefore,our proposed rapid and sensitive HBoV1 detection method,the RPA-Cas12a-fluorescence assay,shows promising potential for early on-site diagnosis of HBoV1 infection in the fields of public health and health care.The established RPA-Cas12a-fluorescence assay is rapid and reliable method for human bocavirus 1 detection.The RPA-Cas12a-fluorescence assay can be completed within 40 min with robust specificity and sensitivity of 0.5 copies/μl.
基金supported by the Scientific and Innovative Action Plan of Shanghai(21N31900800)Shanghai Rising-Star Program(23QB1403500)+4 种基金the Shanghai Sailing Program(20YF1443000)Shanghai Science and Technology Commission,the Belt and Road Project(20310750500)Talent Project of SAAS(2023-2025)Runup Plan of SAAS(ZP22211)the SAAS Program for Excellent Research Team(2022(B-16))。
文摘Traditional transgenic detection methods require high test conditions and struggle to be both sensitive and efficient.In this study,a one-tube dual recombinase polymerase amplification(RPA)reaction system for CP4-EPSPS and Cry1Ab/Ac was proposed and combined with a lateral flow immunochromatographic assay,named“Dual-RPA-LFD”,to visualize the dual detection of genetically modified(GM)crops.In which,the herbicide tolerance gene CP4-EPSPS and the insect resistance gene Cry1Ab/Ac were selected as targets taking into account the current status of the most widespread application of insect resistance and herbicide tolerance traits and their stacked traits.Gradient diluted plasmids,transgenic standards,and actual samples were used as templates to conduct sensitivity,specificity,and practicality assays,respectively.The constructed method achieved the visual detection of plasmid at levels as low as 100 copies,demonstrating its high sensitivity.In addition,good applicability to transgenic samples was observed,with no cross-interference between two test lines and no influence from other genes.In conclusion,this strategy achieved the expected purpose of simultaneous detection of the two popular targets in GM crops within 20 min at 37°C in a rapid,equipmentfree field manner,providing a new alternative for rapid screening for transgenic assays in the field.
文摘Genome editing is considered as the most widely used approach of the present era. It had become a basic need of the current micro and molecular biological experiments. Gene engineering finds its widespread applications in medical, industry and agricultural sector. Unlike previous genetic engineering practices to insert or delete a part of genetic material at random place, genome editing allows the precise manipulation of DNA at a specific location. Zinc Finger Nucleases (ZFNs), Transcription Activator like Effector Nucleases (TALENs), Clustered Regularly Interspresed Short Palindromic repeats (CRISPR/Cas system) and meganucleases (recombinases) are the prime tools for editing an organism’s genome. Genome editing tools have an advantage to selectively delete or to integrate specific genes at specific loci. Use of recombinases for specifying site has further reduced time to integrate genes site specifically. Site specific gene stacking by the use of recombinases coupled with ZFNs, TALENs, or CRISPR/Cas genes have paved new pathways to target genes site specifically and to improve germplasm in lesser time than conventional breeding approaches.
基金supported by the National Key Research and Development Plan of China[2018YFC1602500]the Natural Science Foundation of Tianjin[19JCZDJC39900]
文摘Objective To establish an ultra-sensitive,ultra-fast,visible detection method for Vibrio parahaemolyticus(VP).Methods We established a new method for detecting the tdh and trh genes of VP using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 12a(CRISPR/Cas12a)combined with recombinase polymerase amplification and visual detection(CRISPR/Cas12a-VD).Results CRISPR/Cas12a-VD accurately detected target DNA at concentrations as low as 10^(-18)M(single molecule detection)within 30 min without cross-reactivity against other bacteria.When detecting pure cultures of VP,the consistency of results reached 100%compared with real-time PCR.The method accurately analysed pure cultures and spiked shrimp samples at concentrations as low as 10^(2)CFU/g.Conclusion The novel CRISPR/Cas12a-VD method for detecting VP performed better than traditional detection methods,such as real-time PCR,and has great potential for preventing the spread of pathogens.
文摘Hepatitis C virus(HCV)infection represents a significant health problem and represents a heavy load on some countries like Egypt in which about 20%of the total population are infected.Initial infection is usually asymptomatic and result in chronic hepatitis that give rise to complications including cirrhosis and hepatocellular carcinoma.The management of HCV infection should not only be focus on therapy,but also to screen carrier individuals in order to prevent transmission.In the present,molecular detection and quantification of HCV genome by real time polymerase chain reaction(PCR)represent the gold standard in HCV diagnosis and plays a crucial role in the management of therapeutic regimens.However,real time PCR is a complicated approach and of limited distribution.On the other hand,isothermal DNA amplification techniques have been developed and offer molecular diagnosis of infectious dieses at point-of-care.In this review we discuss recombinase polymerase amplification technique and illustrate its diagnostic value over both PCR and other isothermal amplification techniques.
基金Project supported by the National Natural Science Foundation of China(Nos.30871436,30973297,and 31171194)the National Basic Research Program(973)of China(No.2010CB945002)+1 种基金the Ministry of Education of China(No.200804220011)Shandong Provincial Science and Technology Key Program(No.2009GG10003039),China
文摘To solve the problem of embryonic lethality in conventional gene knockouts, site-specific recombinase （SSR） systems （Cre-loxP, FIp-FRT, and φC31） have been used for tissue-specific gene knockout. With the combination of an SSR system and inducible gene expression systems （tetracycline and tamoxifen）, stage-specific knockout and transgenic expression can be achieved. The application of this ＂SSR＋inducible＂ conditional tool to genomic manipulation can be extended in various ways. Alternatives to conditional gene targeting, such as conditional gene trapping, multipurpose conditional alleles, and conditional gene silencing, have been developed. SSR systems can also be used to construct precise disease models with point mutations and chromosomal abnormalities. With these exciting achievements, we are moving towards a new era in which the whole genome can be manipulated as we wish.
基金supported by Grants from the National Natural Science Foundation of China(31430032,31830033,81971080,and 81671356)the Program for Changjiang Scholars and Innovative Research Teams in University(IRT_16R37)+1 种基金the Science and Technology Program of Guangdong(20188030334001)the Guangzhou Science and Technology Project(201707020027,201704020116)。
文摘Astrocytes are the most abundant cell type in the central nervous system(CNS).They provide trophic support for neurons,modulate synaptic transmission and plasticity,and contribute to neuronal dysfunction.Many transgenic mouse lines have been generated to obtain astrocyte-specific expression of inducible Cre recombinase for functional studies;however,the expression patterns of inducible Cre recombinase in these lines have not been systematically characterized.We generated a new astrocyte-specific Aldh1 l1-CreER^(T2)knock-in mouse line and compared the expression pattern of Cre recombinase between this and five widely-used transgenic lines(hGfap-CreER^(T2)from The Jackson Laboratory and The Mutant Mouse Resource and Research Center,Glast-CreER^(T2),Cx30-CreER^(T2),and Fgfr3-iCreER^(T2))by crossing with Ai14 mice,which express tdTomato fluorescence following Cre-mediated recombination.In adult Aldh1 l1-CreER^(T2):Ai 14 transgenic mice,tdTomato was detected throughout the CNS,and five novel morphologicallydefined types of astrocyte were described.Among the six evaluated lines,the specificity of Cre-mediated recombination was highest when driven by Aldh1 l1 and lowest when driven by hGfap;in the latter mice,co-staining between tdTomato and NeuN was observed in the hippocampus and cortex.Notably,evident leakage was noted in Fgfr3-iCreER^(T2)mice,and the expression level of tdTomato was low in the thalamus when Cre recombinase expression was driven by Glast and in the capsular part of the central amygdaloid nucleus when driven by Cx30.Furthermore,tdTomato was clearly expressed in peripheral organs in four of the lines.Our results emphasize that the astrocyte-specific CreER^(T2)transgenic lines used in functional studies should be carefully selected.
基金supported by the National Natural Science Foundation of China(31522057 and 31872451 to LZ,31720103917 and 31872452 to ZF)。
文摘African swine fever(ASF)is an infectious disease caused by African swine fever virus(ASFV)with clinical symptoms of high fever,hemorrhages and high mortality rate,posing a threat to the global swine industry and food security.Quarantine and control of ASFV is crucial for preventing swine industry from ASFV infection.In this study,a recombinase polymerase amplification(RPA)-CRISPR-based nucleic acid detection method was developed for diagnosing ASF.As a highly sensitive method,RPA-CRISPR can detect even a single copy of ASFV plasmid and genomic DNA by determining fluorescence signal induced by collateral cleavage of CRISPR-lw Cas13 a(previously known as C2c2)through quantitative real-time PCR(q PCR)and has the same or even higher sensitivity than the traditional q PCR method.A lateral flow strip was developed and used in combination with RPA-CRISPR for ASFV detection with the same level of sensitivity of Taq Man q PCR.Likewise,RPA-CRISPR is capable of distinguishing ASFV genomic DNA from viral DNA/RNA of other porcine viruses without any cross-reactivity.This diagnostic method is also available for diagnosing ASFV clinical DNA samples with coincidence rate of 100%for both ASFV positive and negative samples.RPA-CRISPR has great potential for clinical quarantine of ASFV in swine industry and food security.
基金supported by Chinese National Key Program on Basic Research (Nos. 2006CB943501 and 2006BAI23B01-3)Key Project for Drug Discovery and Development in China (No. 2009ZX09501-027)+1 种基金Key Project for Infectious Diseases in China (No. 2008ZX10002-016)E-Institutes of Shanghai Municipal Education Commission (E03003)
文摘Parietal cells are one of the largest epithelium cells of the mucous membrane of the stomach that secrete hydrochloric acid. To study the function of gastric parietal cells during gastric epithelium homeostasis, we generated a transgenic mouse line, namely, Atp4b-Cre, in which the expression of Cre recombinase was controlled by a 1.0 kb promoter of mouse β-subunit of H^＋-, K^＋-ATPase gene （Atp4b）. In order to test the tissue distribution and excision activity of Cre recombinase in vivo, the Atp4b-Cre transgenic mice were bred with the reporter strain ROSA26 and a mouse strain that carries Smad4 conditional alleles （Smad4Ca/Co）. Multiple-tissue PCR of Atp4b-Cre;Smad4Co/＋ mice revealed that the recombination only happened in the stomach. As indicated by LacZ staining, ROSA26;Atp4b-Cre double transgenic mice showed efficient expression of Cre recombinase within the gastric parietal cells. These results showed that this Atp4b-Cre mouse line could be used as a powerful tool to achieve conditional gene knockout in gastric parietal cells.
基金funded by National Natural Science Foundation of China (No. 32071899)Walmart Foundation (No. UA2020– 154)。
文摘creening of foodborne pathogens is important to prevent contaminated foods from their supply chains.n this study, a portable detection device was developed for rapid, sensitive and simple detection of viable almonella using a finger-actuated microfluidic chip and an improved recombinase aided amplification (RAA) assay. Improved propidium monoazide(PMAxx) was combined with RAA to enable this device to distinguish viable bacteria from dead ones. The modification of PMAxx into dead bacteria, the magnetic xtraction of nucleic acids from viable bacteria and the RAA detection of extracted nucleic acids were performed using the microfluidic chip on its supporting device by finger press-release operations. The fluorescent signal resulting from RAA amplification of the nucleic acids was collected using a USB camera nd analyzed using a self-developed smartphone App to quantitatively determine the bacterial concenration. This device could detect Salmonella typhimurium in spiked chicken meats from 1.3 × 10^(2) CFU/m L o 1.3 × 10^(7) CFU/m L in 2 h with a lower detection limit of 130 CFU/m L, and has shown its potential for on-site detection of foodborne pathogens.
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 National Key R&D Program of China[2017YFC200503]National Natural Science Foundation of China[No.42077399].
文摘Objective To establish a sensitive,simple and rapid detection method for African swine fever virus(ASFV)B646L gene.Methods A recombinase-aided amplification-lateral flow dipstick(RAA-LFD)assay was developed in this study.Recombinase-aided amplification(RAA)is used to amplify template DNA,and lateral flow dipstick(LFD)is used to interpret the results after the amplification is completed.The lower limits of detection and specificity of the RAA assay were verified using recombinant plasmid and pathogenic nucleic acid.In addition,30 clinical samples were tested to evaluate the performance of the RAA assay.Results The RAA-LFD assay was completed within 15 min at 37°C,including 10 min for nucleic acid amplification and 5 minutes for LFD reading results.The detection limit of this assay was found to be 200 copies per reaction.And there was no cross-reactivity with other swine viruses.Conclusion A highly sensitive,specific,and simple RAA-LFD method was developed for the rapid detection of the ASFV.
基金the National Natural Sci-ence Foundation of China (No. 30430350)the National Science Supporting Program (No. 2006BAI23B01-3).
文摘Osteoblasts participate in bone formation, bone mineralization, osteoclast differentiation and many pathological processes. To study the function of genes in osteoblasts using Cre-LoxP system, we generated a mouse line expressing the Cre recombinase under the control of the rat Collagenlcd （Collα1） promoter （Collα1-Cre）. Two founders were identified by genomic PCR from 16 offsprings, and the integration efficiency is 12.5%. In order to determine the tissue distribution and the activity of Cre recombinase in the transgenic mice, the Coll αl-Cre transgenic mice were bred with the ROSA26 reporter strain and a mouse strain that carries Smad4 conditional alleles （Smad4^Co/Co）. Multiple tissue PCR of Collα1-Cre;Smad4^Co/＋ mice revealed the restricted Cre activity in bone tissues containing osteoblasts and tendon. LacZ staining in the Collα1-Cre;ROSA26 double transgenic mice revealed that the Cre recombinase began to express in the osteoblasts of calvaria at E14.5. Cre activity was observed in the osteoblasts and osteocytes of P10 double transgenic mice. All these data indicated that the Collα1-Cre transgenic mice could serve as a valuable tool for osteoblast lineage analysis and conditional gene knockout in osteoblasts.
基金Supported by Grants from Ministry of Education,Sci-ence,Sports and Culture,the Japanese Government,and from the Japan Ministry of Health,Labour and WelfareFunds from the Cell Science Research Foundation
文摘BACKGROUND：Gene therapy for Parkinson＇s disease is being explored as an effective strategy to restore and protect the function of neuronal cells in the substantia nigra. Regulation of gene expression is necessary for gene therapy to avoid adverse effects due to excessive synthesis of transgene products.OBJECTIVE：Here we developed recombinant adeno-associated virus （AAV） as a viral vector-mediated gene regulation system based on Cre recombinase fused to the mutated ligand-binding domain of the estrogen receptor （CreERT2） ＋ inducing agent tamoxifen. Inducible Cre recombinase was used to reduce tyrosine hydroxylase gene expression and to prevent the excessive increase in dopamine.DESIGN, TIME AND SETTING：A genetic engineering in vitro comparative study and randomized controlled animal experiment. This study was conducted at the Gene Therapy Center, Jichi Medical School, Japan from June 2002 to June 2004.METHODS：To construct a recombinant AAV vector carrying a dopamine synthase gene. The tyrosine hydroxylase gene was inserted using a IoxP fragment that could be regulated by Cre recombinase. The recombinant AAV vector carrying the CreERT2 gene was co-transduced with HEK293 cells and the corpus striatum in a rat model of Parkinson＇s disease, with inducing agent tamoxifen to regulate gene expression.MAIN OUTCOME MEASURES：The levels of dopamine and aromatic L-amino acid decarboxylase （AADC） activity were detected in HEK293 cell medium and in the corpus striatum in a rat model of Parkinson＇s disease using high-performance liquid chromatography. Immunofluorescence double staining was used to observe tyrosine hydroxylase and Cre or AADC co-expression in HEK293 cell medium. Immunohistochemical staining was employed to observe tyrosine hydroxylase and AADC expression and behavioral changes were measured in Parkinson＇s rats.RESULTS：Transfected AAV-CreERT2 and AAV expressing dopamine synthesis enzymes could increase the synthesis of dopamine in HEK293 medium and Parkinson＇s rat striatum （P 〈 0.01） and improve the rotational behavior of Parkinson＇s rats. While tamoxifen markedly reduced overproduction of dopamine caused by cotransfection of viral vectors （P 〈 0.01）, but did not affect the expression and activity of AADC.CONCLUSION：The application of AAV vector-encoded tyrosine hydroxylase gene under the gene regulation system of Cre-ERT2〉, after tamoxifen treatment, can effectively control the generation of genetically modified products to reduce the production of excessive dopamine in vivo and in vitro. Therefore, this method can increase the safety of gene therapy.
基金the Agricultural Research Development Agency(Public Organization),Thailand(Project No.PRP6205031190).
文摘Xanthomonas oryzae pv.oryzae(Xoo)is a widespread pathogen causing bacterial leaf blight(BLB)disease,devastating rice productivity in many cultivated areas of Thailand.A specific and simple method for Xoo detection is required to improve surveillance of disease transmission and outbreak.This study developed a recombinase polymerase amplification(RPA)assay assisted with CRISPR-cas12a assay(RAC)for Xoo detection from bacterial cell suspension of infected rice samples without DNA extraction.The efficiency of the RAC system for Xoo detection using either Xoo80 or Xoo4009 locus was optimized to amplify and determine the sensitivity and specificity using a Xoo DNA template from bacterial cell suspension of infected rice samples without DNA extraction.The RAC system using the Xoo4009 locus gave a higher specificity than Xoo80 locus,because only Xoo species was amplified positive RPA product with fluorescence signal by cas12a digestion,which indicated no cross reactivity.Optimal RAC using the Xoo4009 locus enabled diagnosis of Xoo presence from both plant extracted samples of Xoo artificially inoculated rice leaves within 3 d post-inoculation without symptomatic BLB appearance,and Xoo naturally infected rice.Findings exhibited that RAC using the Xoo4009 locus offered sensitivity,specificity and simplicity for Xoo detection,with low intensities of Xoo-DNA(1×10^(3) copies/μL)and Xoo-cell(2.5×10^(3) cfu/mL).This developed RAC system showed significantly potential for Xoo detection at point-of-care application for early signs of BLB disease outbreak in rice fields.
基金Supported by Project of the Education Department of Heilongjiang Province (11511035)Dr Start-up Found Research of Northeast Agricultural University
文摘Cre/LoxP site-specified recombination system is mainly used for excision,inversion and integration of target gene.Therefore,this system can be used for plant marker free genetic transformation,site-specific transgene expression and so on.However,the application of this system was limited due to its low expression and excision efficiency.In this study,an intron,which can enhance gene expression in plants,was inserted into Cre by using PCR method.And a modified Cre gene,named Crein,was obtained.This gene was ...
