45 results about "Deoxyribozyme" patented technology

The invention discloses a deoxyribozyme probe for identifying carbapenem-resistant klebsiella pneumoniae and application of the deoxyribozyme probe, and belongs to the technical field of deoxyribozyme probes. The method comprises the following steps: firstly, mixing a phosphorylated library chain, a substrate chain and a connecting chain, then, carrying out covalent linkage to construct a DNA library, firstly, carrying out reverse screening, separating and purifying a DNA band of an uncut substrate RNA site, constructing a chain-shaped DNA library by using the obtained DNA band, carrying out forward screening, separating and purifying the DNA band of the cut substrate RNA site, carrying out PCR (Polymerase Chain Reaction) amplification, and recovering a positive-sense chain, so as to obtain the DNA library. The deoxyribozyme probe is obtained by performing repeated screening and enriching, and the probe can recognize carbapenem-resistant klebsiella pneumoniae with high specificity and has the potential of exerting advantages in the aspect of biosensing application.

The invention discloses vibrio parahaemolyticus deoxyribozyme screening and label-free biosensor development. The vibrio parahaemolyticus deoxyribozyme screening and label-free biosensor development comprises the following steps: (1) obtaining a vibrio parahaemolyticus deoxyribozyme sequence; (2) optimizing reaction conditions of the vibrio parahaemolyticus label-free biosensor; and (3) detecting the vibrio parahaemolyticus. The detection principle of the sensor is as follows: when vibrio parahaemolyticus exists, deoxyribozyme is triggered to be self-cleaved, a generated cleaved short chain can be used as a primer for starting rolling circle amplification (RCA), a large number of long-chain DNA products with repeated series G-quadruplex sequences are generated by amplifying a designed RCA annular template, G-quadruplex and ThT can form a G-quadruplex / ThT compound, and the long-chain DNA products can be used for detecting the vibrio parahaemolyticus. The fluorescence is generated under the excitation wavelength of 439 nm, and the higher the concentration of the vibrio parahaemolyticus is, the higher the fluorescence intensity of the system is, so that the simple, convenient, rapid, low-cost and high-sensitivity detection of the vibrio parahaemolyticus is realized.

The invention provides a pathogen viable bacteria detection kit based on endogenous protein activated deoxyribozyme. The kit comprises a deoxyribozyme recognition element and a signal transduction element. The deoxyribozyme recognition element is composed of a substrate chain and an enzyme chain, and the signal transduction element is composed of two DNA reporter probes (Sub-F and Sub-Q), wherein the tail ends of the two DNA reporter probes are respectively marked with a fluorescence staining group and a fluorescence quenching group. The deoxyribozyme recognition element can recognize specific endogenous protein of target pathogenic viable bacteria and activate an enzyme chain to cut a substrate chain to generate two independent substrate chain fragments. And then a signal transduction element is introduced to realize specific output of a fluorescence signal. The kit provided by the invention can realize detection of living salmonella by targeting endogenous protein, can sensitively detect 190 CFU / mL of living salmonella with abundance as low as 0.1%, and has a good application prospect in the directions of food safety detection and clinical examination.

The invention discloses a cadmium ion and lead ion detection system and method based on CRISPR and deoxyribozyme, and the method comprises the following steps: forming active deoxyribozyme by using target ions and a recognition probe, cutting a redundant sequence in a substrate probe, releasing a semi-activator, and cooperatively activating the activity of CRISPR-Cas12a with the other semi-activator in the system. According to the system, the signal-to-noise ratio and the sensitivity of detection are improved by utilizing the effect of inhibiting cooperative activation by redundant fragments in semi-activators. According to the detection method, nano material modification on the substrate probe is not needed, magnetic separation is not needed, and the detection cost is reduced. The detection process only needs two steps of room temperature incubation reaction, and the two steps are carried out in one reaction tube, so that cross contamination possibly caused by multi-tube reaction is avoided, and the detection process is simplified. The method can be applied to detection of cadmium ions and lead ions in rice or serum samples, and has wide application prospects in the fields of food safety, medical detection and the like.

The invention relates to a normal temperature amplification-CRISPR Cas12a one-pot method detection system and a nucleic acid detection method based on the detection system. The detection system consists of a normal-temperature nucleic acid amplification system (unit I) which focuses on target signal amplification and a CRISPR Cas12a system (unit II) which focuses on target recognition and signal output. By means of a self-driven and deoxyribozyme-mediated reaction equilibrium transfer strategy, the equilibrium in the initial stage of the reaction tends to the unit I, and the equilibrium in the middle and later stages of the reaction tends to the unit II, so that the compatibility of the two units is remarkably improved. By means of the system, high-sensitivity and high-specificity portable one-pot detection of nucleic acid targets can be achieved.

The invention belongs to the technical field of biology, and particularly relates to a method for rapidly and multiply detecting breast cancer related protein markers based on cas12a and application of the method. HER2, CEA, CA15-3 and CD63 are taken as protein markers, are fixed on magnetic beads through biotin and streptavidin and are used for recognizing and capturing proteins, meanwhile, protein detection is converted into deoxyribozyme recognition of a cyclic sequence, and signal amplification is performed through cas12a; the method provided by the invention can be used for detecting four breast cancer protein markers in a system in a short time, is simple to operate, does not need to heat up, has high accuracy and specificity, accelerates the progress of breast cancer diagnosis and postoperative and prognostic diagnosis, and provides reference for subsequent treatment of clinicians.

The application discloses a method for imaging magnesium ions in living cells based on chemically modified deoxyribozyme, and belongs to the technical field of metal ion imaging. The method comprises the following steps: chemically modifying deoxyribozyme 10-23, screening and obtaining deoxyribozyme 10-23 (CaBn) which is modified with carboxyl (Ca) at the 8th position of the catalytic ring and benzene ring (Bn) at the 12th position; performing biochemical characterization and comparison; constructing a fluorescence sensor responding to magnesium ions; characterizing the performance; and applying the fluorescence sensor to imaging magnesium ions in living cells. Compared with the wild type, the application can catalyze the cleavage reaction under the condition of lower concentration of magnesium ions; therefore, the fluorescence sensor constructed from the deoxyribozyme can more effectively respond to lower concentration of magnesium ions in vitro, and the detection limit reaches 0.03 mM; in addition, the fluorescence sensor can perform fluorescence imaging on endogenous magnesium ions in living cells, and provides a new molecular tool for the field of molecular biology.

The invention belongs to the technical field of biological detection, and particularly relates to an escherichia coli non-amplification type rapid detection method based on a deoxyribozyme probe. The method comprises the following steps: detecting Escherichia coli by adopting a fluorescent chip, mixing Escherichia coli lysate and RFD-EC recognition molecules for reaction, dripping into the fluorescent chip for reaction, and detecting the fluorescence intensity after the reaction; the fluorescent chip takes paper as a substrate and is coated with d-DNA, the nucleotide sequence of the d-DNA is shown as SEQ ID NO.3, and the 5'end of the d-DNA is marked with biotin. Fluorescent DNA molecules are enriched through a fluorescent chip micro-fluidic technology, and detection can be completed within 0.5-1 hour without enrichment culture in combination with multi-channel fluorescence detection. The detection lower limit of the method is as low as 100 CFU, and the method has the advantages of rapidness, sensitivity and low cost, is suitable for on-site rapid detection of Escherichia coli in clinical samples and environmental samples, and has important application value in the fields of pollution control and the like.

The present invention discloses a capillary monolithic column modified with a deoxyribozyme nanoflower, a preparation method thereof, and an application thereof in separating chiral molecules, belonging to the field of pharmaceutical analysis. The present invention synthesizes a deoxyribozyme-based nanoflower chiral selector, the nucleotide sequence of the single-stranded DNA template of the deoxyribozyme being shown in SEQ ID NO.1, and the synthesized deoxyribozyme nanoflower having good pH and temperature stability. The prepared deoxyribozyme nanoflower is bonded to a graphene oxide-functionalized capillary silica monolithic column, and chiral molecules are separated under electrophoretic conditions, achieving baseline separation of 2'-deoxyadenosine, atenolol, propranolol, tyrosine, and nafopam enantiomers.

The invention relates to a deoxyribozyme binding arm, a kit, a biosensor and a nucleic acid detection method. The deoxyribozyme binding arm is of an annular structure and comprises a catalytic core A sequence of deoxyribozyme, a monomer amplicon recognition region, a sequence of a fragment containing a detection probe and a deoxyribozyme substrate recognition region; wherein the catalytic core part sequence of the deoxyribozyme comprises a part of sequence in any one of 8-17 type deoxyribozyme, E6 type deoxyribozyme or 10-23 type deoxyribozyme. The invention provides a deoxyribozyme binding arm and a multifunctional DNA nano-machine obtained by combining the deoxyribozyme binding arms, which integrate cutting enhanced rolling circle amplification, self-cutting DNAzyme and rolling circle amplification technologies, construct a self-cascade amplification nano-machine, and can perform molecular signal amplification on the existence of a formulated sequence. The system exhibits an increase in cascade reaction efficiency due to the minimization of the number of independent molecular diffusion / collision events.

The application discloses a kind of photoactivation manganese ion bridging type deoxyribozyme probe preparation and its application in Cistanche inhibiting acetylcholinesterase activity.The probe is pSD@MnO2 Composite structure, which is composed of manganese dioxide nanosheet and functional nucleic acid assembly adsorbed on its surface, the assembly includes S chain labeled with fluorescence / quenching group and containing deoxyribozyme cleavage site, and pD chain partially hybridized with S chain and containing photocleavage site.Its preparation includes nucleic acid probe assembly, MnO2 Nanosheet complexing and purification steps.When applied, AChE catalytic product decomposes MnO2, releases Mn 2+ And nucleic acid chain; after centrifugation, pD chain is cut by ultraviolet light activation trigger, and released DNAzyme is cut under the assistance of Mn 2+ It produces amplified fluorescence signal; by comparing signal change before and after adding inhibitor, inhibition activity can be quantitatively evaluated.The application combines photocontrol activation with enzyme cascade amplification, realizes high sensitivity and operation synchronism of detection process, and is especially suitable for high-throughput rapid screening of AChE inhibitor in Cistanche and other natural products.

The present invention discloses a porous silicon deoxyribozyme fluorescent probe and its application in evaluating the anticancer activity of traditional Chinese medicine. The fluorescent probe comprises amino-modified porous silica nanoparticles, fluorescent molecules loaded in the nanoparticle pores, and DNA hairpins HP1 and HP2 covalently linked to the nanoparticle surface. The HP1 sequence contains a complementary sequence to the microRNA to be detected, and the HP2 sequence contains a zinc ion-specific deoxyribozyme cleavage site. After HP1 binds to the microRNA, the root is opened, the HP1 loop undergoes a conformational change, and binds to the HP2 loop nucleotide sequence. With the assistance of zinc ions, the zinc ion-specific deoxyribozyme is activated, which then cuts HP2 at the cleavage site, releasing the fluorescent molecules in the nanoparticle pores. The microRNA is detected based on the intensity of the fluorescent molecules. The probe can specifically and sensitively detect trace amounts of microRNA in a system.

The invention discloses a paper-based sensor device based on a deoxyribozyme probe and application, and belongs to the technical field of analysis and detection. The paper-based sensor based on the deoxyribozyme probe by using the fluorescence signal is constructed, complex treatment on a sample is not needed, only a bacterial lysis buffer needs to be added into the sample for lysis, the deoxyribozyme is enabled to cut the deoxyribozyme probe by the generated escherichia coli CIM specificity, so that a sequence fragment containing an FAM group modified on the deoxyribozyme probe falls off, and the detection result is accurate. A complementary sequence modified at a detection line is used for capturing, a fluorescence signal is read to realize the detection purpose, and the whole reaction process can be completed within 30 minutes. The method integrates the processes of bacterial lysis, reaction sampling, bacterial detection and the like, avoids the complex and time-consuming operation process of a traditional method, has the analysis performance of rapidness, simplicity, rapidness, low cost and the like, and has potential application value in analysis and detection of various complex liquid bacteria in the clinical medicine field.

The invention discloses a glyphosate fluorescence detection method based on RNase H cycle amplified magnetic bead-aptamer-Cas9 / deoxyribozyme, belongs to the technical field of environmental monitoring and biological detection, and can realize high-sensitivity and rapid quantitative detection of glyphosate residues in soil, water bodies and agricultural products. According to the method, the glyphosate is combined with an aptamer to release complementary DNA (cDNA) combined with the aptamer, then signal cascade amplification is realized through RNase H-mediated cDNA cyclic utilization, the anti-interference advantage brought by magnetic bead separation is combined, and the known characteristics of Cas9 endonuclease and DNAzyme in the aspects of nucleic acid recognition and cutting are used as signal amplification and transduction means, so that the detection sensitivity of the glyphosate is improved, and the detection sensitivity of the glyphosate is improved. Therefore, trace detection of glyphosate is realized. According to the invention, sensitive detection of other targets can be realized by replacing nucleic acid aptamers capable of specifically recognizing other targets and correspondingly adjusting the sequence of cDNA to maintain base pairing.

The invention belongs to the technical field of agricultural biological protection, and discloses a targeted screen tube-vector insect lysozyme-nano magnesium compound system and application thereof in prevention and control of areca yellows, the compound system comprises an in-plant treatment module and a propagation blocking module, the in-plant treatment module comprises a screen tube targeted delivery unit, and the propagation blocking module comprises a propagation blocking unit. The sieve tube targeted delivery unit is formed by combining betel nut sieve tube navigation peptide ArePEP1 and a lysozyme-nano magnesium complex through a non-covalent bond; the propagation blocking module comprises an antifeedant micro-capsule activated by salivary enzyme of a vector insect, and phytoplasma deoxyribozyme PdeA and an insect antifeedant are encapsulated in the antifeedant micro-capsule; the target sequence of the phytoplasma deoxyribozyme PdeA is 5 '-GGAAACAG-3'; the in-plant treatment module and the propagation blocking module are jointly loaded on the same delivery vehicle. According to the areca yellows prevention and control compound system and the application method, pathogens in plants can be synchronously inhibited, insect propagation can be blocked, and high-altitude accurate delivery can be realized.

The invention discloses a preparation method and application of an aptamer functionalized DNA nano-structure targeting tumor cells, the DNA nano-structure is prepared by performing enzyme digestion, annealing and origami on loop single-stranded DNA produced by a biological method, and particularly relates to optimization of deoxyribozyme in phagocytids, widening of pH range of cut loop single-stranded DNA and shortening of enzyme digestion time. The single-stranded DNA capable of being automatically folded into the DNA nanostructure is efficiently prepared; according to the present invention, the nucleic acid aptamer is inserted into the customized sequence so as to functionalize the customized sequence, and the produced and prepared functionalized DNA nano-structure has characteristics of no toxicity on cells, drug loading, specific tumor cell targeting, and cell toxicity stronger than the free drug, and can achieve the specific targeting and killing effects on the tumor cells; therefore, efficient preparation of the DNA nanostructure can be realized, and functional targeted tumor cell drug release can be carried out.

The invention discloses a droplet microfluidic detection system for detecting pathogenic bacteria based on a deoxyribozyme probe, which belongs to the technical field of microbiological detection, and mainly comprises an automatic sample introduction device, a microfluidic droplet generation chip, a capillary tube-laser induced fluorescence detector and a signal acquisition and analysis device, the pathogen detection process comprises the following steps: respectively and automatically injecting an actual water sample, a deoxyribozyme probe, liquid drop oil, a pathogen lysis solution and a reaction buffer solution into the microfluidic liquid drop generation chip by the automatic sample injection device, stably generating liquid drops, and detecting the liquid drops through the capillary tube-laser induced fluorescence detector, and the signal acquisition and analysis device acquires and analyzes the fluorescence signal. The method has the advantages of high detection flux, high stability, high sensitivity, rapidness and the like, and can be applied to the field of environmental microbiological detection.

The application discloses a double-stranded nucleic acid detection composition based on lambda exonuclease and deoxyribozyme and application thereof, and belongs to the technical field of biological technology, and aims to efficiently and sensitively detect double-stranded nucleic acid. The double-stranded nucleic acid detection composition based on lambda exonuclease and deoxyribozyme comprises a double-stranded nucleic acid detection probe, lambda exonuclease and a reporter molecule, the double-stranded nucleic acid detection probe comprises one long single-stranded DNA named recognition chain R and n short single-stranded DNAs named Dz; the recognition chain R comprises a target binding domain and n Dz binding domains arranged in sequence from 5' to 3' in order; the 5' end of the recognition chain R is modified with a functional group; the Dz is a deoxyribozyme capable of cleaving the reporter molecule when the Dz is single-stranded, and the 5' end of the Dz is modified with sulfur. The application has high sensitivity and specificity, and the detection limit can be as low as a femtomole.

This invention belongs to the medical field and provides a calcium carbonate manganese nanoprobe for in situ imaging detection of vascular epidermal growth factor, its preparation method, and its application. In this strategy, a DNA strand (P1 and P2) containing a protein recognition antibody, a protein recognition sequence, and a deoxyribonuclease, along with a molecular beacon DNA strand (H1), is stirred in a DMEM cell culture medium containing calcium chloride and manganese chloride to prepare the calcium carbonate manganese nanoprobe. In acidic tumor cells, this nanoprobe releases P1, P2, H1, and manganese ions. P1 and P2 can simultaneously recognize proteins, forming a complete deoxyribonuclease center, which catalyzes the cleavage of H1 under the action of the cofactor manganese ions, generating a fluorescent signal. This strategy achieves specific in situ dynamic imaging of low-abundance proteins in vivo and has great potential in biomedical research.

The invention discloses deoxyribozyme targeting enolase 1 and application of deoxyribozyme in preparation of a gene medicine for treating rheumatoid arthritis, and belongs to the technical field of biology. On the basis of a mouse ENO1 mRNA secondary structure, 15 deoxyribozyme is designed and screened, Dz8 has the strongest ENO1 mRNA cutting capacity, and the expression level of the gene can be effectively reduced; meanwhile, the Dz8 has Mg-dependent efficient ENO1 mRNA cleavage activity and time-dependent multi-turnover kinetic characteristics, ENO1 expression can be remarkably inhibited at the gene and protein levels, then inflammatory factor secretion is reduced, the glycolysis level is regulated and controlled, and the Dz8 has important application prospects in the field of rheumatoid arthritis gene therapy. The invention provides a new target and a treatment strategy for rheumatoid arthritis gene therapy, and Dz8 is expected to become a potential tool for rheumatoid arthritis gene therapy.

The invention discloses a method for imaging intracellular nucleic acid based on chemically modified deoxyribozyme. The method comprises the following operation steps: carrying out chemical functional group modification on each site of a catalytic ring of deoxyribozyme 8-17, and screening to obtain a deoxyribozyme 8-17 variant 11Bn which is subjected to benzyl modification on a No.11 site of the catalytic ring; carrying out biochemical characterization on the variants; by taking miRNA-21 as an example, a multi-component nuclease (MNAzyme) system is constructed based on a variant and is used for specifically detecting intracellular nucleic acid and characterizing the detection performance of the system; manganese dioxide nanosheets for delivering nucleic acid are synthesized, and characterization of material morphology, size and the like is carried out; and the probe is applied to imaging of intracellular nucleic acid in living cells. The nucleic acid sensor constructed on the basis of the modified variant can effectively perform fluorescence response at a lower concentration; in addition, the sensor constructed by the invention does not need a transfection reagent or signal amplification, can perform sensitive fluorescence imaging in living cells, and provides a new molecular tool for diagnosis and treatment of related diseases.

This invention provides a Csm6-based deoxyribonuclease sensor, characterized by comprising the following components: (1) a deoxyribonuclease enzyme chain and a deoxyribonuclease substrate chain, wherein the nucleotide sequence of the deoxyribonuclease substrate chain is shown in SEQ ID No. 1 or SEQ ID No. 2 of the sequence listing, and the nucleotide sequence of the deoxyribonuclease enzyme chain is shown in SEQ ID No. 10 of the sequence listing; (2) a Csm6 protease; and (3) a single-stranded RNA reporter probe modified with fluorescent and quenching groups, wherein the sequence of the single-stranded RNA reporter probe modified with fluorescent and quenching groups is shown in SEQ ID No. 16 of the sequence listing. This invention also provides an application of this deoxyribonuclease sensor for lead detection. The deoxyribonuclease sensor provided by this invention can improve the sensitivity and selectivity of existing biosensors in lead ion detection.

This invention discloses a deoxyribozyme probe for recognizing strontium ions and its applications, belonging to the field of deoxyribozyme probe technology. The nucleotide sequence of the deoxyribozyme probe provided by this invention is any one of the sequences shown in SEQ ID NO:1 to SEQ ID NO:9. Specifically, it is a cis-structured deoxyribozyme probe composed of a deoxyribozyme and a substrate chain with a fluorescent group and a quenching group. The substrate chain sequence is shown in SEQ ID NO:10, and the deoxyribozyme sequence is any one of the sequences shown in SEQ ID NO:17 to SEQ ID NO:25. The deoxyribozyme probe provided by this invention can efficiently and specifically recognize strontium ions, thereby achieving accurate detection of the target ion, with a strontium ion response concentration of 2 mM or higher. This probe has good application prospects in the fields of biosensing and ion detection.

The invention discloses a deoxyribozyme probe capable of specifically distinguishing a G-quadruplex and a single-strand structure of a G-rich sequence and application of the deoxyribozyme probe, and belongs to the technical field of deoxyribozyme probes. The method comprises the following steps: firstly, connecting a phosphorylated library enzyme chain with a substrate chain containing RNA (Ribonucleic Acid) modification sites to construct a linear DNA (Deoxyribose Nucleic Acid) library; then, under the condition that the pH is 7.4, co-incubating the library and a G-rich sequence in a single-chain state, separating and purifying a DNA strip for cutting an RNA site in the library, recovering a positive-sense strand after PCR amplification, and carrying out multiple rounds of screening to obtain the chain deoxyribozyme probe. The obtained probe can specifically detect a G-rich sequence in a single-chain form, has no response to a G-quadruplex structure, and has a good application prospect in the field of biosensing.

The invention discloses a double-stranded nucleic acid detection composition based on lambda exonuclease and deoxyribozyme and application of the double-stranded nucleic acid detection composition, belongs to a composition for detecting nucleic acid in the technical field of biology and a use method of the composition, and aims to solve the technical problem of how to efficiently and sensitively detect double-stranded nucleic acid. The double-stranded nucleic acid detection composition based on the lambda exonuclease and the deoxyribozyme comprises a double-stranded nucleic acid detection probe, the lambda exonuclease and a reporter molecule, wherein the double-stranded nucleic acid detection probe comprises a long single-stranded DNA named as a recognition chain R and n short single-stranded DNAs named as Dz; the recognition chain R contains a target binding domain and n Dz binding domains which are sequentially and adjacently arranged in the direction from 5'to 3 '; the 5'end of the recognition chain R is modified with a functional group, when the Dz is a single chain, the Dz is deoxyribozyme capable of enzyme digestion of the reporter molecule, and the 5 'end of the Dz is subjected to sulfo-modification. The kit has high sensitivity and specificity, and the detection limit can be as low as a fly-friction level.

The invention relates to the field of molecular machines, in particular to a signal system for continuous autonomous movement of a derailment-free three-drive DNA harvester along a nanogold solidified nucleic acid substrate track, a preparation method and application. The signal system comprises a three-drive DNA harvester and a nanogold curing substrate track; the three-drive DNA harvester comprises a DNA tetrahedron, a nucleic acid aptamer used for recognizing target cells is assembled at one fixed point vertex of the DNA tetrahedron, and locking foot chains are assembled at the other three vertexes of the DNA tetrahedron; the nanogold curing and nucleic acid substrate orbital is formed by covalent binding of three linear sequences and nanogold particles and complementary pairing of part of basic groups; the three linear sequences are two split enzyme chains and a substrate chain, and the substrate chain modifies a fluorophore and has a deoxyribozyme digestion site. The signal system provided by the invention has the advantages of no cytotoxicity, nuclease degradation resistance, three-drive autonomous continuous movement, avoidance of orbital detachment and sequential precise recognition mediated by double biomarkers.

The present application provides a method for regulating the activity of functional nucleic acid, which comprises modifying one or more bases of the functional nucleic acid to inactivate the functional nucleic acid. Preferably, the functional nucleic acid or the substrate of the functional nucleic acid is modified to inactivate the functional nucleic acid, and then the modified group is removed to activate the functional nucleic acid. The present application also provides a deoxyribozyme molecular probe, which comprises domain a, domain b and domain c. The deoxyribozyme molecular probe is obtained by screening 6 A closed Dz, which realizes m 6 A high-efficiency and sensitive detection of demethylase and screening and detection of inhibitor small molecule drugs.

The invention relates to the technical field of molecular detection, in particular to deoxyribozyme for detecting BK polyoma virus and application of deoxyribozyme. The deoxyribozyme comprises a catalytic core and a binding arm connected with the 5'end and / or the 3 'end of the catalytic core, wherein the catalytic core has the activity of cutting nucleic acid. The invention further provides a method for detecting the BK polyomavirus, the method comprises the step that a sample to be detected makes contact with the deoxyribozyme, by means of the nucleic acid detection method, the BK polyomavirus as low as 0.1 aM can be detected, and extremely high sensitivity and specificity are achieved.

The present invention is directed to a composition for a target sequence detection in double- stranded DNA, wherein the composition comprises i) a first oligonucleotide and a second oligonucleotide for a multi-component deoxyribozyme (MNAzyme), wherein said first and second oligonucleotides are capable of forming substrate binding arms, a catalytic core, and target-binding arms of said MNAzyme, said target-binding arms being complementary to said target sequence in double-stranded DNA, ii) a peptide nucleic acid (PNA) comprising a sequence identical to said target sequence, wherein said PNA is capable of invading the double-stranded DNA at the site of said target sequence and opening the double-stranded DNA by binding to the sequence complementary to said target sequence in said double- stranded DNA leaving said target sequence single-stranded and thus free for said target- binding arms of said MNAzyme to bind, and iii) a substrate oligonucleotide comprising a sequence complementary to the sequence of said substrate binding arms, wherein said substrate binding arms of said MNAzyme engage said substrate oligonucleotide so that said catalytic core of said MNAzyme is capable of modifying said substrate oligonucleotide when said target-binding arms of said MNAzyme bind or are bound to said target sequence in the presence of a cofactor. The present invention is also directed to a kit comprising said composition and to methods of using said composition.

This application belongs to the field of bioanalytical detection technology, specifically disclosing a detection system and method for live Salmonella based on deoxyribonuclease activation. The detection system includes a Sub probe, a deoxyribonuclease probe, a hairpin probe, hyperbranched dendritic nanomolecules, a crRNA / Cas12a binary complex, a fluorescent probe, and magnetic beads. The hyperbranched dendritic nanomolecules include substrate A, substrate B, and a trigger strand B probe. Substrate A consists of an A-F strand probe, an A-Q strand probe, and a helper strand A probe, while substrate B consists of a B-F strand probe, a B-Q strand probe, and a helper strand B probe. This detection system specifically recognizes ribonuclease H2 released only by the metabolism of live Salmonella and utilizes it to activate the Sub-Dz substrate, ensuring from the source that only live bacteria can trigger the subsequent reaction. This effectively solves the problem of interference from dead bacteria, achieving highly sensitive, highly specific, and rapid detection of live Salmonella.