CN113684283A - Probe design method and device for detecting pathogenic microorganisms - Google Patents

Probe design method and device for detecting pathogenic microorganisms Download PDF

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CN113684283A
CN113684283A CN202110997796.2A CN202110997796A CN113684283A CN 113684283 A CN113684283 A CN 113684283A CN 202110997796 A CN202110997796 A CN 202110997796A CN 113684283 A CN113684283 A CN 113684283A
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probe
probes
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food
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CN113684283B (en
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林德春
金桃
张智闵
詹太平
蒋华
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Guangdong Magigene Technology Co ltd
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    • C12Q1/00—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
    • C12Q1/68—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving nucleic acids
    • C12Q1/6876—Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes
    • C12Q1/6888—Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes for detection or identification of organisms
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    • C12Q1/00—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
    • C12Q1/68—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving nucleic acids
    • C12Q1/6813—Hybridisation assays
    • C12Q1/6834—Enzymatic or biochemical coupling of nucleic acids to a solid phase
    • C12Q1/6837—Enzymatic or biochemical coupling of nucleic acids to a solid phase using probe arrays or probe chips
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    • C12Q1/00—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
    • C12Q1/68—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving nucleic acids
    • C12Q1/6876—Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes
    • C12Q1/6888—Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes for detection or identification of organisms
    • C12Q1/6893—Nucleic acid products used in the analysis of nucleic acids, e.g. primers or probes for detection or identification of organisms for protozoa
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    • C12Q2600/00—Oligonucleotides characterized by their use
    • C12Q2600/166—Oligonucleotides used as internal standards, controls or normalisation probes
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    • Y02A50/30—Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change

Abstract

The invention discloses a method and a device for designing a probe for detecting pathogenic microorganisms, and belongs to the technical field of microorganism detection. The method for designing the probe can conveniently and quickly complete the probe design by utilizing an efficient screening algorithm, and is not only suitable for food-borne pathogenic parasites, but also suitable for the probe design of other pathogens. The probe for the food-borne pathogenic parasite has the advantages of strong specificity, high sensitivity, good stability, convenience and rapidness, is particularly suitable for sample detection with low parasite loading capacity, and provides better technical support for infection diagnosis and treatment and food safety detection.

Description

Probe design method and device for detecting pathogenic microorganisms
Cross Reference to Related Applications
The invention belongs to divisional application of Chinese patent application with the application date of 2021.01.05 and the application number of 202110008380.3, and the invention name of 'a probe, a chip, a kit and a method for detecting 4 food-borne pathogenic parasites', and the whole content of the divisional application is incorporated by reference.
Technical Field
The invention belongs to the technical field of microorganism detection, and particularly relates to a method and a device for designing a probe for detecting pathogenic microorganisms.
Background
Food-borne pathogenic parasitic diseases are one of the most concerned public health problems in the world today, and are caused by food-borne pathogenic parasitic diseases of humans, which occur when food and drinking water are contaminated by parasites through various ways and food and water containing parasites during infection enter the human body as uncooked food or semi-uncooked food. In recent years, food-borne pathogenic parasitic diseases become new 'rich and noble diseases', particularly, the number of infected people of urban residents in coastal economically developed areas is on the rise, and the food-borne pathogenic parasitic diseases in China have the characteristics of wide distribution, serious harm to people and livestock and the like.
Food-borne pathogenic parasites mainly include trematodes, cestodes, toxoplasma, trichina, sporozoites and the like. The traditional food-borne pathogenic parasite detection technology comprises staining smear examination, floating egg collection method, precipitation egg collection method, McLeod counting method, imaging method and the like, and the traditional method has the limitations of complex operation, overlong period, low positive rate and the like, can not meet the requirement of food safety rapid detection, and is not beneficial to the treatment of events such as food-borne pathogenic parasite infection and the like. In recent years, a series of pathogen nucleic acid molecule detection technologies including PCR, gene chip, high-throughput sequencing gene detection, etc. have been developed. PCR has better specificity and sensitivity, but only one pathogen can be detected at a time, and the defect of low flux exists, while the second-generation sequencing technology has the defects of long period (more than 24 h), low flexibility, high cost, complex whole process and certain difficulty in reading data at present although the detected pathogen range is large. The gene chip has high sensitivity and specificity, low cost, flexible operation, high timeliness and strong pertinence, so that the gene chip is very suitable for pathogen detection of specific types of samples and is suitable for clinical and food safety detection.
The gene chip (GeneChip) is also called MicroArray technology (MicroArray), and mainly comprises 5 technical links: probe construction, chip preparation, sample preparation, chip experiment, signal detection and result interpretation. The design of probes on a gene chip is one of the core factors for embodying the detection efficiency of the chip, then the existing specific probe sequence design algorithm is excavated from the conserved genes of microorganisms, such as 16SrRNA of bacteria, ITS of fungi and the like, and a long sequence comparison mode is adopted, so that the algorithm program lacks sufficient flexibility, and the probe sequences lack sufficient coverage and sensitivity. Can not meet the design requirement of a large-scale parasite detection gene chip. In addition, the existing chip design method does not design the arrangement of various probes by considering the regional nonuniformity of the fluorescence signals on the microarray, and the existing chip design method lacks the standardization processing of the fluorescence signals.
Disclosure of Invention
In order to solve at least one of the above technical problems, the technical solution adopted by the present invention is as follows:
in a first aspect, the invention provides a probe combination for detecting one or more of 4 food-borne pathogenic parasites, wherein the 4 food-borne pathogenic parasites are angiostrongylus cantonensis, cryptosporidium parvum, toxoplasma gondii and cestode pork.
Angiostrongylus cantonensis (Angiostrongylus cantonensis) is a pathogen causing Angiostrongylus cantonensis disease (food-borne parasitic disease), and its adult lives in the pulmonary artery of mice, and humans are abnormal hosts for this insect. The larva of the parasite is infected by eating the larva of the parasite such as agate snail, ampullaria gigas, snail or vegetable which contains the larva of the parasite, and the larva of the parasite migrates to the central nervous system of the organism after infecting the human body, and causes acidophilic encephalitis and meningoencephalitis, wherein the symptoms of the larva often show as nervous system symptoms such as severe headache, nausea, jet vomiting, neck stiffness and the like. The disease is prevalent in tropical and subtropical regions, is distributed in China in a scattered manner, and is mostly generated in coastal regions.
Cryptosporidium parvum is an important opportunistic pathogenesis of zoonosis of food-source/water-source people and animals in global distribution, obligate intracellular parasites parasitize in mammals and human small intestines after infection, and is one of important diarrhea pathogens, Cryptosporidium parvum caused by the infection of the parasites is commonly seen in people with low immune function or immunodeficiency and is manifested as acute and chronic diarrhea and accompanied with symptoms of fever, nausea, cough, dyspnea and the like.
Toxoplasma gondii (Toxoplasma gondii), also known as a triose, is an obligate intracellular parasite whose final host is a feline. Human body is often infected by contacting or eating polluted water and food, and the insect body can flow along with blood and reach the brain, heart, eyeground and other parts to cause toxoplasmosis. Most of the people with normal immunity have no obvious symptoms, but can be killed by disseminated infection when the immunity of the organism is low or the immunity is deficient. In addition, infection of pregnant women with Toxoplasma gondii can lead to miscarriage, stillbirth or malformed fetus.
Taenia solium (Taenia solium) is the main parasitic tapeworm in China, and the final host is human. Human infection often occurs by miseating raw or uncooked pork containing the pork cestode larvae- -cysticercus. The parasitic sites of cysticercosis cellulosae are wide, including subcutaneous tissue, central nervous system, eye, liver and lung, and the induced diseases are mainly subcutaneous and muscle cysticercosis cellulosae, cysticercosis cellulosae and cysticercosis cellulosae.
In some embodiments of the invention, the probe combination comprises probes capable of detecting at least two food-borne pathogenic parasites of angiostrongylus cantonensis, cryptosporidium parvum, toxoplasma gondii and cestodes pork.
In some preferred embodiments of the invention, the probe combination comprises probes capable of detecting at least three food-borne pathogenic parasites of angiostrongylus cantonensis, cryptosporidium parvum, toxoplasma gondii and cestodes pork.
In some more preferred embodiments of the invention, the probe combination comprises probes capable of detecting four food-borne pathogenic parasites, guanidium guangzhou, cryptosporidium parvum, toxoplasma gondii and cestodes pork.
In the present invention, the probe combination is also referred to as a probe composition, and refers to a composition comprising a plurality of probes.
In some embodiments of the invention, the probe for detecting angiostrongylus cantonensis comprises at least one of probes respectively having nucleotide sequences shown in SEQ ID Nos. 1-6; the probe for detecting the cryptosporidium parvum comprises at least one of probes respectively having nucleotide sequences shown in SEQ ID No. 7-12; the probes for detecting Toxoplasma gondii comprise at least one of the probes respectively having nucleotide sequences shown in SEQ ID No. 13-18; the probe for detecting the taenia solium comprises at least one of probes respectively having nucleotide sequences shown in SEQ ID Nos. 19-24.
In some embodiments of the invention, the probe for detecting angiostrongylus cantonensis comprises probes respectively having nucleotide sequences shown in SEQ ID Nos. 1-6; the probe for detecting the cryptosporidium parvum comprises probes respectively having nucleotide sequences shown in SEQ ID No. 7-12; the probes for detecting Toxoplasma gondii comprise probes respectively having nucleotide sequences shown in SEQ ID Nos. 13-18; the probes for detecting the taenia solium comprise probes respectively having nucleotide sequences shown in SEQ ID Nos. 19-24.
In the present invention, probes directed against specific food-borne pathogenic parasites are designed using the following method:
s1, obtaining a reference genome sequence of the food-borne pathogenic parasite;
s2, breaking the obtained reference genome sequence into a 50nt k-mer set, firstly, aligning the k-mer set to a ginseng reference genome sequence hg19, and filtering k-mers with identity greater than or equal to 85; then comparing the k-mer set of the food-borne pathogenic parasite with 50nt k-mer sets interrupted by other food-borne pathogenic parasites by the same method in pairs, filtering probes with the number of continuously-compared bases being more than 20nt, screening out an initial specific probe sequence set of the food-borne pathogenic parasite, and counting the abundance of the probe sequence;
s3, filtering the initial specific probe sequence set:
s31, comparing the probe sequence in the species-specific probe set with RefSeq nucleic acid database of bacteria, viruses, fungi and other parasites, if the comparison length is more than 20nt, calculating the free energy of the nucleic acid between the probe sequence and the target sequence, and if the free energy of the nucleic acid is less than-30, removing the probe sequence;
s32, if the same continuous basic group of the probe appears for 5 times, removing the probe sequence;
s4, and reserving the top N most abundant probe sequences from the rest probe sequences as the probe sequences of the food-borne pathogenic parasite. Wherein, N is 1 to 50, preferably, N is 5 to 10, and more preferably, N is 6.
In some embodiments of the invention, if multiple food-borne pathogenic parasites are detected simultaneously, it is desirable to obtain reference genomes for other food-borne pathogenic parasites simultaneously.
Further, the reference genome sequences of other food-borne pathogenic parasites are broken into 18nt k-mer sets, the obtained probes are respectively subjected to sequence alignment with the 18nt k-mer set after the step S2 and before the step S3, and if the identity of a certain probe aligned with at least one sequence in the 18nt k-mer sets in the sequence alignment result is more than or equal to 85, the probe sequence is removed.
In some embodiments of the present invention, the probes for the 4 food-borne pathogenic parasites are obtained simultaneously by the following steps:
s1, obtaining reference genome sequences of 4 food-borne pathogenic parasites and a ginseng reference genome sequence hg 19;
s2, breaking the obtained reference genome sequences of the 4 food-borne pathogenic parasites into 50nt k-mer sets, firstly, comparing the k-mer sets to a ginseng reference genome sequence hg19, and filtering k-mers with the identity greater than or equal to 85; then taking each parasite as a unit, pairwise comparing k-mer sets among the units, filtering probes with the continuously-compared base number larger than 20nt, screening out an initial specific probe sequence set of the food-borne pathogenic parasite, and counting the abundance of the probe sequence;
further, generating an 18nt k-mer set taking each parasite as a unit from the reference genome sequence sets of the 4 parasites, and performing sequence comparison on the 18nt k-mer set and the initial specific probe sequence set obtained in the last step by using blastn, wherein if the identity of a certain probe compared with at least one sequence in the 18nt k-mer set in the sequence comparison results of different varieties is more than or equal to 85, the probe sequence is removed;
s3, filtering the initial specific probe sequence set:
s31, comparing the probe sequences in the initial specific probe set with RefSeq nucleic acid databases of bacteria, viruses, fungi and other parasites, if the comparison length is more than 20nt, calculating the free energy of the nucleic acids of the probe sequences and the target sequences, and if the free energy of the nucleic acids is less than-30, removing the probe sequences;
s32, if the same continuous basic group of the probe appears for 5 times, removing the probe sequence;
s4, and reserving the first 6 most abundant probe sequences from the rest probe sequences as the probe sequences of the food-borne pathogenic parasite.
In a second aspect, the present invention provides a gene chip comprising the probe set according to the first aspect of the present invention.
Furthermore, the gene chip also comprises a negative control probe. In some preferred embodiments of the invention, the negative control probe comprises a probe having the nucleotide sequence shown in SEQ ID No. 25. In some embodiments of the invention, the negative control probe is a probe having the nucleotide sequence shown in SEQ ID No. 25.
Furthermore, the gene chip also comprises a global quality control probe. In some preferred embodiments of the invention, the global quality control probe comprises a probe having the nucleotide sequence shown in SEQ ID No. 26. In some embodiments of the invention, the global quality control probe is a probe having a nucleotide sequence shown in SEQ ID No. 26.
Furthermore, the gene chip also comprises a positive control probe. In some preferred embodiments of the present invention, the positive control probe comprises at least one of the probes having the nucleotide sequences shown in SEQ ID Nos. 27 to 32, respectively. In some embodiments of the invention, the positive control probes include probes having the nucleotide sequences shown in SEQ ID Nos. 27 to 32, respectively. In other embodiments of the present invention, the positive control probe is composed of probes having nucleotide sequences represented by SEQ ID Nos. 27 to 32, respectively.
In some embodiments of the invention, the gene chip comprises a probe combination for detecting one or more of 4 food-borne pathogenic parasites, and further comprises a negative control probe, a global quality control probe and a positive control probe, wherein the 4 food-borne pathogenic parasites are angiostrongylus cantonensis, cryptosporidium parvum, toxoplasma gondii and taenia solium, and the probes for detecting the angiostrongylus cantonensis comprise at least one of probes respectively having nucleotide sequences shown in SEQ ID Nos. 1-6; the probe for detecting the cryptosporidium parvum comprises at least one of probes respectively having nucleotide sequences shown in SEQ ID No. 7-12; the probes for detecting Toxoplasma gondii comprise at least one of the probes respectively having nucleotide sequences shown in SEQ ID No. 13-18; the probes for detecting the taenia solium comprise at least one of probes respectively having nucleotide sequences shown in SEQ ID Nos. 19-24, the negative control probe comprises a probe having a nucleotide sequence shown in SEQ ID No.25, the global quality control probe comprises a probe having a nucleotide sequence shown in SEQ ID No.26, and the positive control probe comprises at least one of probes respectively having nucleotide sequences shown in SEQ ID Nos. 27-32.
In some embodiments of the invention, the gene chip comprises a probe combination for detecting 4 food-borne pathogenic parasites, and further comprises a negative control probe, a global quality control probe and a positive control probe, wherein the 4 food-borne pathogenic parasites are angiostrongylus cantonensis, cryptosporidium parvum, toxoplasma gondii and taenia solium, and the probes for detecting the angiostrongylus cantonensis comprise probes respectively having nucleotide sequences shown in SEQ ID Nos. 1-6; the probe for detecting the cryptosporidium parvum comprises probes respectively having nucleotide sequences shown in SEQ ID No. 7-12; the probes for detecting Toxoplasma gondii comprise probes respectively having nucleotide sequences shown in SEQ ID Nos. 13-18; the probes for detecting the taenia solium comprise probes respectively having nucleotide sequences shown in SEQ ID Nos. 19-24, the negative control probe is a probe having a nucleotide sequence shown in SEQ ID No.25, the global quality control probe is a probe having a nucleotide sequence shown in SEQ ID No.26, and the positive control probe comprises probes respectively having nucleotide sequences shown in SEQ ID Nos. 27-32.
In a specific embodiment of the invention, the gene chip is an Agilent CGH chip (microarray) comprising 192 characteristic points (array points) of 16 rows by 12 columns. The layout of the probes on the microarray is as follows:
sample application position control probe (Agilent CGH chip with): a total of 40 sites, 24 sites distributed at the four corners of the microarray, and the remaining 16 sites randomly dispersed in the microarray;
negative control probe: 1 probe sequence is repeated for 15 times to form 15 monitoring sites which are randomly distributed in the microarray;
positive control probe: repeating the sequence for 2 times to form 12 monitoring sites which are positioned in 1 row and 4-9 columns of the microarray and 16 rows and 4-9 columns of the microarray;
global quality control probe: the total number of the probe sequences is 1, the probe sequences are repeated for 5 times to form 5 monitoring sites, and the monitoring sites are positioned in the center of the microarray and spread in a radial mode towards four corners.
Food-borne pathogenic parasite probes: a total of 4 parasites, 6 probe sequences per species, each repeated 5 times, constituting 120 detection sites, randomly distributed in the microarray.
In a third aspect, the present invention provides a kit comprising the probe set of the first aspect or the gene chip of the second aspect.
Further, the kit also comprises a reagent for extracting the genomic DNA of the sample to be detected.
Still further, the kit further comprises a nucleic acid amplification reagent and a fluorescent labeling reagent.
Still further, the kit further comprises a purification reagent.
In a fourth aspect of the invention, a method of detecting a food-borne pathogenic parasite comprises the steps of:
s1, obtaining the genome DNA of the sample to be detected;
s2, performing nucleic acid amplification, fluorescence labeling and purification on the obtained genome DNA;
s3, performing hybridization detection using the gene chip according to the second aspect of the present invention;
and S4, judging the detection result according to the detected probe signal.
In some embodiments of the invention, in step S2, the nucleic acid amplification is non-specific random amplification; fluorescence labeling was performed using Cyanine 3-dUTP.
In some embodiments of the present invention, the gene chip of step S3 is specifically: the kit comprises a probe combination for detecting 4 food-borne pathogenic parasites, and also comprises a negative control probe, a global quality control probe and a positive control probe, wherein the 4 food-borne pathogenic parasites are angiostrongylus cantonensis, cryptosporidium parvum, toxoplasma gondii and taenia solium, and the probe for detecting the angiostrongylus cantonensis comprises probes respectively having nucleotide sequences shown in SEQ ID Nos. 1-6; the probe for detecting the cryptosporidium parvum comprises probes respectively having nucleotide sequences shown in SEQ ID No. 7-12; the probes for detecting Toxoplasma gondii comprise probes respectively having nucleotide sequences shown in SEQ ID Nos. 13-18; the probes for detecting the taenia solium comprise probes respectively having nucleotide sequences shown in SEQ ID Nos. 19-24, the negative control probe is a probe having a nucleotide sequence shown in SEQ ID No.25, the global quality control probe is a probe having a nucleotide sequence shown in SEQ ID No.26, and the positive control probe comprises probes respectively having nucleotide sequences shown in SEQ ID Nos. 27-32.
In some embodiments of the invention, the gene chip is an agilent CGH chip (microarray) comprising 192 feature points (array points) of 16 rows by 12 columns. The layout of the probes on the microarray is as follows:
sample application position control probe (Agilent CGH chip with): a total of 40 sites, 24 sites distributed at the four corners of the microarray, and the remaining 16 sites randomly dispersed in the microarray;
negative control probe: 1 probe sequence is repeated for 15 times to form 15 monitoring sites which are randomly distributed in the microarray;
positive control probe: repeating the sequence for 2 times to form 12 monitoring sites which are positioned in 1 row and 4-9 columns of the microarray and 16 rows and 4-9 columns of the microarray;
global quality control probe: the total number of the probe sequences is 1, the probe sequences are repeated for 5 times to form 5 monitoring sites, and the monitoring sites are positioned in the center of the microarray and spread in a radial mode towards four corners.
Food-borne pathogenic parasite probes: there were 4 parasites, 6 probe sequences per species, each probe was repeated 5 times to form 120 detection sites randomly distributed on the microarray.
Further, the step S4 is:
s41, scanning and feature extraction: scanning the cleaned chip in a Multi-TIFF mode by using an agile chip scanner to obtain chip characteristic data, and extracting signal characteristics by using characteristic extraction software to obtain probe signal characteristic data;
s42, data quality inspection: and (3) performing quality inspection on the probe signal characteristic data in the previous step, setting a signal detection threshold value to be 100, and if: a) all negative control probes were not detected (fluorescence signal values were below threshold); b) more than 50% of positive control probes are detected; c) all the global quality control probes are detected, and the data quality inspection is qualified if no signal supersaturation occurs;
s43, data quality control: a) detecting a global quality control probe and a parasite probe which are higher than a detection signal threshold value (a signal value of 100); b) calculating the signal average value QC _ intensity of the global quality control probemean(ii) a c) Normalization of fluorescence signal values: for each Parasite probe i (Parasite) detectedi) Calibrating probe information according to equation 1Number, and obtaining quality control data:
Correct_Parasitei_intensity＝Parasitei_intensity/QC_intensitymean(formula 1)
(4) Parasite detection and judgment: since the parasite probes were all repeated 5 times, the probe was specific for the parasite: a) firstly, counting probes with repeated detection times more than or equal to 3; b) then counting the number of probes meeting the condition a; c) and if the number of the probes counted in the step b is more than or equal to 2, the parasite is considered to be detected positively.
In the present invention, the sample to be tested can be any body fluid, including but not limited to blood, cerebrospinal fluid, alveolar lavage, sputum, and tissue fluid.
As such, in some embodiments of the present invention, in step S1, the obtaining of the genomic DNA of the test sample may be performed by performing nucleic acid extraction using methods conventional in the art.
The invention has the advantages of
Compared with the prior art, the invention has the following beneficial effects:
(1) the method for designing the probe can conveniently and quickly complete the probe design by utilizing an efficient screening algorithm, and is not only suitable for food-borne pathogenic parasites, but also suitable for the probe design of other pathogens.
(2) The probe for the food-borne pathogenic parasite has the advantages of strong specificity, high sensitivity and good stability.
(3) The gene chip of the invention comprises a probe aiming at the food-borne pathogenic parasite, a negative control probe, a positive control probe and a global quality control probe, and further improves the sensitivity and the accuracy of the gene chip detection by designing the spatial arrangement characteristics of various probes.
(4) The method can be used for quickly (less than 10 hours), sensitively and accurately detecting the food-borne pathogenic parasites in the samples, and is particularly suitable for detecting the samples with low parasite loading.
(5) The invention can provide basis for the differential diagnosis and anti-infection treatment of food-borne pathogenic parasite infection and provides an effective, rapid and stable means for screening food safety detection (parasite contamination).
Drawings
FIG. 1 is a schematic view showing the distribution of probes of the gene chip of the present invention.
FIG. 2 is a schematic diagram showing the specimen slides (tiff format) scanned by the gene chip scanner according to the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more apparent, the present invention is further described in detail below with reference to the following embodiments.
Examples
The following examples are used herein to demonstrate preferred embodiments of the invention. It will be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function in the invention, and thus can be considered to constitute preferred modes for its practice. Those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit or scope of the invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs and the disclosures and references cited herein and the materials to which they refer are incorporated by reference.
Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.
The experimental procedures in the following examples are conventional unless otherwise specified. The instruments used in the following examples are, unless otherwise specified, laboratory-standard instruments; the test materials used in the following examples were purchased from a conventional biochemical reagent store unless otherwise specified.
EXAMPLE 14 specific Probe design for food-borne pathogenic parasites
This example addresses 4 food-borne pathogenic parasites: probe design is carried out on angiostrongylus cantonensis, cryptosporidium parvum, toxoplasma gondii and cestodes suis, and the specific steps are as follows:
(1) genome database construction of 4 food-borne pathogenic parasites: the reference genomic sequences contained in this database were the construction of specific probes for 4 food-borne pathogenic parasites. The inventors obtained genome sequences of 4 food-borne pathogenic parasites from various authoritative databases in the field, such as NCBI NT library (ftp:// ftp. NCBI. nlm. nih. gov/blast/db/FASTA/NT. gz), RefSeq and GenBank library (ftp:// ftp. NCBI. nlm. nih. gov/genes), parasite reference sequence library (https:// eupathdb. org/eupathdb), and further removed redundant repeats and less-credible genome sequences according to the following removal principle: the number of insect strains per parasite is set as the upper limit: and 50, if the number of the insect strains exceeds 50, randomly reserving 50 reference genomes, ensuring the simplification, the completeness, the accuracy and the comprehensiveness of a microbial sequence and improving the coverage, the sensitivity and the quality of a probe sequence.
Through the processing of the steps, the finally obtained database contains comprehensive and complete genome sequences of 4 parasites, and specifically, the number of insect strains with complete reference genomes contained in each parasite is respectively as follows: 7 strains of angiostrongylus cantonensis, 20 strains of cryptosporidium parvum, 18 strains of Toxoplasma gondii and 8 strains of Taenia solium.
(2) Designing a specific probe:
a. inputting the reference genome sequence and the reference genome sequence of the 4 parasites in the constructed reference genome database (hg 19);
b. species-specific initial probesets were predicted using GSMer v1.0 software:
i. after disruption of the reference genomic sequence set of 4 parasites into 50nt k-mer sets using meryl (kmer software module), the k-mer sets were first aligned to hg19 using blastn v2.2.26, filtering k-mers with identity greater than or equal to 85; then taking each parasite as a unit, carrying out pairwise comparison on k-mer sets among the units by using mapMers (k-mer software module), filtering k-mers with the number of continuously-compared bases being more than 20nt, finally screening out an initial specific probe set (50nt k-mers) of each parasite, and counting the abundance of probe sequences;
generating 18ntk-mer sets with each parasite as a unit from the reference genome sequence sets of 4 parasites, performing sequence alignment on the 18nt k-mer sets and the initial specific probe sequence set obtained in the previous step by using blastn, and removing the probe sequences if the identity is greater than or equal to 85 in the sequence alignment results of different species, thereby obtaining the initial specific probe sets of each parasite.
c. Further filtration of species-specific initial probe set:
i. performing sequence alignment on the probe and a RefSeq nucleic acid database of bacteria, viruses, fungi and other parasites by using blastn, if the alignment length is more than 20nt, calculating the Free energy (in kcal/mol) of the probe sequence and a target sequence, and if the Free energy of the nucleic acid is less than-30, removing the probe sequence;
if the same continuous basic groups of the probe appear for 5 times, removing the probe sequence to obtain a probe sequence set with good specificity;
d. and finally, the first 6 probe sequences with the highest abundance are reserved from the rest probe sequences to be used as probe sequences of each parasite, so that a probe sequence set with good conservation is obtained.
The specific nucleotide sequences (all 50nt) are shown in Table 1:
TABLE 1 Probe information
Figure BDA0003234653900000121
Figure BDA0003234653900000131
Furthermore, the probes can be combined to prepare a kit for detecting one or more of 4 food-borne pathogenic parasites.
Example 2 Gene chip and preparation thereof
The gene chip designed in example 1, which includes the probes for 4 food-borne pathogenic parasites, a control probe and a global quality control probe, is designed as follows:
1. design of control probe and global quality control probe
Negative control probe design: the inventors generated 1 ten thousand 50NT artificial sequences using computer simulation and aligned the sequence set to NCBI NT library using blastn (ftp:// ftp. NCBI. nlm. nih. gov/blast/db/FASTA/NT. gz), reserving the sequence set with the number of consecutive alignment bases less than 18NT and the identity less than 85, and yielded 424 sequences in total. 1 sequence was randomly selected as a negative control probe, and in this example, the sequence of the negative control probe was selected as follows:
Probe No.25(SEQ ID No.25)：
CAATGGCCAATTAAGATCATATCGAGTGAGATTCTCTCAGAATGTTTATT
designing a global quality control probe: the method and the design of a negative control probe, wherein the global quality control probe has the following sequence:
Probe No.26(SEQ ID No.26)：
AATGACCCTTTCGTACTGTATAGACCGATGGTGCCATGTTGAAACAACTT
design of positive control probe: from 16S nucleic acid sequence database of bacteria and archaea Silva (https:// www.arb-silva.de/) Screening 50nt conserved sequences which are shared by 16S sequences of human common colonizing genera (staphylococcus, aeromonas, sphingomonas, enterococcus and pseudomonas) and natural common genera (desulfurization vibrio, bacillus, xanthomonas, nitrosococcus, rhizobium, Eggerthia and the like), and selecting 6 positive Probe sequences in total, wherein the positive control Probe sequences are shown as Probe No 27-32, and the lists of respectively targeted bacteria are shown as Table 2:
TABLE 2 Positive control probes
Figure BDA0003234653900000141
2. Preparation of Gene chip
The inventors used a CGH (genome-wide hybridization) chip of the Agilent (https:// www.agilent.com /) platform, which included a solid support on which probes were immobilized during preparation.
Generally, probes are immobilized on a solid support in a microarray fashion with a certain spatial distribution, and the inventors have specifically designed a 16-row × 12-column microarray, each of which can detect one sample. The distribution characteristics of the various probes are shown in FIG. 1 and described in more detail below:
sample application position control probe (Agilent CGH chip with): there were 40 sites, 24 sites distributed at the four corners of the microarray, and the remaining 16 sites randomly dispersed in the microarray.
Negative control probe: the total number of the probe sequences is 1, the probe sequences are repeated 15 times to form 15 monitoring sites, and the monitoring sites are randomly distributed in the microarray. According to the above design rule, any sample tested by using the negative control probe should show a negative result.
Positive control probe: the total number of the probe sequences is 6, the probe sequences are repeated for 2 times to form 12 monitoring sites, and the monitoring sites are positioned on 1 row multiplied by 4-9 columns and 16 rows multiplied by 4-9 columns of the microarray. According to the above design rules, at least 50% of the positive probes should show positive results in any sample tested by the positive control probes.
Global quality control probe: the total number of the probe sequences is 1, the probe sequences are repeated for 5 times to form 5 monitoring sites, and the monitoring sites are positioned in the center of the microarray and spread in a radial mode towards four corners.
In order to standardize the fluorescent signal of the pathogenic parasite probe, when the probe was assigned to oligonucleotide synthesis by Jieren, a reagent (as a control sample) was obtained by fluorescent labeling with Cyanine 5 fluorescent dye.
Food-borne pathogenic parasite probes: each probe was replicated 5 times each to form detection sites randomly distributed in the microarray.
For example, for 2 food-borne pathogenic parasites, each 6 probes, repeated 5 times, can result in 60 detection sites.
For another example: for 4 food-borne pathogenic parasites, each 6 probes were repeated 5 times to obtain 120 detection sites.
Furthermore, the gene chip can be prepared into a kit for detecting one or more of 4 food-borne pathogenic parasites.
Example 3 detection of sample to be tested Using Gene chip
In this embodiment, the inventors used the gene chip prepared in example 2 and containing 24 probes for 4 food-borne pathogenic parasites to detect a sample to be tested, and in this embodiment, 1 specimen (sample 1-4) was collected from 4 vegetables (often susceptible to parasite contamination) such as cauliflower, shepherd's purse, lotus root, and cress, respectively, and the sample information is shown in table 3:
table 3 sample information for example 3
Sample name Corresponding vegetable
Sample
1 Cauliflower
Sample 2 Capsella bursa-pastoris
Sample
3 Lotus root
Sample 4 Oenanthe stolonifera (L.) Roem
The detection specifically comprises the following steps:
1. preparation of genomic DNA (gDNA) from test sample
The inventors used the DNA extraction kit of Agilent CGH MicroArray to perform gDNA extraction on a sample to be tested:
(1) nucleic acid extraction and quality inspection: after DNA extraction of each sample, using Nanodrop to measure the DNA concentration (ng/ul) and A260/A280 (nucleic acid purity index of the sample);
(2) sampling: the sampling volume of each sample was calculated from the amount of 500ng of DNA, i.e. the volume: 500ng/DNA concentration, sampling according to the corresponding volume of each sample, placing in a broken tube, and supplementing H2O to 50. mu.L. Setting the interruption time to 90 seconds;
(3) balancing Onebubble MagBeads at room temperature for 30min in advance, fully oscillating and uniformly mixing to ensure that no obvious magnetic bead precipitation exists;
(4) adding 60 mu L of Onebubble MagBeads (1.2 x) into the low adsorption tube/eight-connected tube, adding the interruption product in the step (2), mixing uniformly by vortex, collecting liquid on the tube wall instantly, and standing for 5min at room temperature;
(5) placing the low adsorption tube or the eight-connected tube on a magnetic frame, and removing the supernatant after the solution in the tube is clarified;
(6) adding 200 mu L of 80% freshly prepared ethanol into a 1.5mL low adsorption tube or an octal tube, standing for 30 seconds, removing a supernatant, and repeating the operation steps until the supernatant is completely removed;
(7) placing the low adsorption tube or the eight-connected tube on a magnetic frame, standing at room temperature for 1-2 min until the magnetic beads are dried or opening the tube and placing the tube on a metal bath at 45 ℃ until the surfaces of the magnetic beads are dried and cracked without water and ethanol residue at the bottom of the tube;
(8) removing the centrifuge tube from the magnetic frame, adding 15 μ L of incubated nucleic-free water to resuspend the magnetic beads, vortexing or blowing, mixing, collecting the tube wall liquid instantly, and standing at room temperature for 3 min;
(9) the low adsorption tube or the octal tube is placed on a magnetic frame, and when the solution in the tube is clarified, 13. mu.L of supernatant is transferred to a new PCR tube for the next labeling.
The total amount of nucleic acid and specific activity of fluorescent label in each sample of this example are shown in Table 4:
TABLE 4 information table for quality control of sample nucleic acid in example 3
Figure BDA0003234653900000161
2. Nucleic acid amplification and fluorescent labeling
The inventors used the Agilent SureTag Complete DNA Labeling Kit to perform nucleic acid amplification and fluorescent Labeling on gDNA, comprising the following steps:
(1) mu.L of Random primer was added to the purified gDNA after 13. mu.L of the above fragment, and after mixing, the following denaturation reaction was carried out: maintaining at 98 deg.C for 3min and 4 deg.C;
(2) the following reagents were directly added to the above denaturation reaction system: 15.5. mu.L of gDNA and primer mix, 5. mu.L of 5 × Reaction buffer, 2.5. mu.L of 10 × dNTPs, 1.5. mu.L of Cyanine3-dUTP, 0.5. mu.L of LExo (-) Klenow, for a total of 25. mu.L;
(3) after the mixture is uniformly mixed by blowing or vortex oscillation by using a liquid transfer gun, quickly centrifuging and collecting liquid on the tube wall, and removing bubbles;
(4) the reaction system was placed on a PCR instrument with the hot lid set at 75 ℃ and the following procedure was run: keeping at 37 deg.C for 2h, 65 deg.C for 10min, and 4 deg.C.
3. Purification of fluorescently labeled gDNA
(1) Instantly separating the marked sample, transferring to a 1.5mL low adsorption tube, marking the tube correspondingly, adding 430 μ L of 1 × TE (PH 8.0) into the marked sample, and mixing uniformly for later use;
(2) loading the purification column of the purification device into a matched collection tube, making corresponding marks, sucking all marked gDNA in the previous step into the collection column, covering a cover with 14000g, and centrifuging for 10 min;
(3) discarding the filtrate, collecting the tube, recovering the collected tube, adding 480 μ L of 1 × TE (pH 8.0) into the collected tube, covering the tube with a cap of 14000g, and centrifuging for 10 min;
(4) taking out the collection column, inverting the collection column in a new 2mL centrifuge tube, marking the tube with a corresponding mark, and centrifuging the tube for 1min at 1000g to obtain a purified sample (the volume is 20-32 muL);
(5) detecting the total amount of the nucleic acid after fluorescent labeling and the specific activity of the fluorescent label: selecting a chip mode on the Nanodrop, selecting Cyanine3 corresponding to fluorescence, carrying out detection after zeroing by using 1 × TE, and recording the total amount of nucleic acid (Yield) and Specific Activity (Specific Activity) fed back by a machine.
The total amount of nucleic acid and specific activity of fluorescent label in each sample of this example are shown in Table 5:
TABLE 5 Total nucleic acid amount and specific activity of fluorescent marker of example 3
Figure BDA0003234653900000171
Figure BDA0003234653900000181
4. Chip hybridization and washing
The inventors performed ChIP Hybridization using the Agilent Oligo aCGH/ChIP-on-ChIP Hybridization Kit, comprising the following steps:
(1) the purified sample was concentrated to 14.3. mu.L (total 5. mu.g), and after hybridization was performed according to the configuration in Table 6, the mixture was blown up and mixed, and after flash dissociation the reaction was placed on a PCR instrument with a hot lid temperature of 105 ℃ and the following procedure was run: keeping at 98 deg.C for 3min, 37 deg.C for 30min, and 37 deg.C.
TABLE 6 hybridization System of example 3
Figure BDA0003234653900000182
(2) And (3) hybridization:
a. firstly, a clean gasket is placed in the Agilent chamber, the label of the gasket faces upwards and is aligned with the rectangular part at the bottom of the chamber, and the gasket is ensured to be flush with the base of the chamber;
b. then sucking 55 mu L of the sample at the temperature of 37 ℃ in the previous step to the middle of the rubber ring on the gasket to avoid generating bubbles, and reversely buckling the chip on the gasket;
c. then, covering the chamber cover, and screwing down the knob;
d. each assembled device was loaded into an incubator carousel, a matched chamber was taken, the hybridization chamber was rotated vertically to wet the slides, and the mobility of the bubbles was assessed.
e. The rotation speed of the hybridization rotator was set at 20rpm and hybridization was carried out at 67 ℃ for 4 hours.
(3) Chip cleaning: after hybridization, the chip is taken out at room temperature, placed in washing liquor 1 (reagent of Agilent kit) and set at 250rpm, and washed by shaking at room temperature for 5 min; then washing solution 2 (reagent of Agilent kit) is set at 200rpm, shaking and washing is carried out for 1min at 39 ℃, and finally liquid on the surface of the chip is removed and scanning is carried out within 4 h.
5. Signal detection and result interpretation
(1) Scanning and feature extraction: scanning the cleaned chip in a Multi-TIFF mode by using an agile chip scanner to obtain chip characteristic data (TIFF picture format, one sample is shown in FIG. 2), and then extracting signal characteristics from a TIFF file by using characteristic extraction software (Agilent Feature extraction) v12.1 to obtain probe signal characteristic data;
(2) and (3) data quality inspection: and (3) performing quality inspection on the probe signal characteristic data in the previous step, setting a signal detection threshold value to be 100, and if: a) all negative control probes were not detected (fluorescence signal values were below the machine detection threshold); b) more than 50% of positive control probes are detected; c) and detecting all the global quality control probes, and if no signal supersaturation occurs, the quality inspection of the data detected this time is qualified.
(3) And (3) data quality control: a) detecting a global quality control probe and a parasite probe which are higher than a detection signal threshold value (a signal value of 100); b) calculating the signal average value QC _ intensity of the global quality control probemean(ii) a c) Normalization of fluorescence signal values: for each Parasite probe i (Parasite) detectedi) And (3) correcting the signal value of the probe according to a formula 1, and obtaining quality control data:
Correct_Parasitei_intensity＝Parasitei_intensity/QC_intensitymean(formula 1)
(4) Parasite detection and judgment: since the parasite probes were all repeated 5 times, the probe was specific for the parasite: a) firstly, counting probes with repeated detection times more than or equal to 3; b) then counting the number of probes meeting the condition a; c) and if the number of the probes counted in the step b is more than or equal to 2, the parasite is considered to be detected positively.
(5) The experimental result judgment criteria are as follows:
a) if the quality test of the nucleic acid extraction fails to pass the quality standard, the nucleic acid concentration is lower than 20 ng/. mu.L or A260/A280 is lower than 1.2. The sample experiment is unqualified, and the sample experiment processing link is carried out again;
b) if the quality inspection of the nucleic acid extraction meets the quality standard, but the total amount of the nucleic acid after the nucleic acid amplification is lower than 4 mug or is higher than 8 mug, and the specific activity of the fluorescent marker is lower than 10 or is higher than 30, the steps of the nucleic acid amplification and the fluorescent marker fail to pass the quality standard, the sample is unqualified in experimental treatment, and only an experimental quality inspection report is displayed;
c) if the quality inspection, nucleic acid amplification and fluorescence labeling steps of nucleic acid extraction all meet the quality standard, carrying out a complete chip hybridization experiment, carrying out data quality inspection after scanning the chip, and if the data quality inspection is not qualified, only displaying an experiment and a biological signal quality inspection report;
d) and if the a, the b and the c pass the quality standard, performing data quality control analysis and parasite detection judgment analysis, and obtaining the identification result of the food-borne pathogenic parasite.
Using the above method, the test results of the samples to be tested are shown in table 7:
TABLE 7 detection of food-borne pathogenic parasites according to example 3
Figure BDA0003234653900000201
Table 7 illustrates: -indicates no detection
It was found by analysis that sample 1 was contaminated with cryptosporidium parvum, whereas sample 4 was contaminated with Toxoplasma gondii.
EXAMPLE 4 timeliness of the method for detecting parasites by Gene chip
In order to test the operation time of the method for detecting parasites by using a gene chip in embodiment 3 of the invention, 5 collected cerebrospinal fluid specimens suspected of being infected by food-borne pathogenic parasites are divided into two specimens, wherein one specimen is detected by using the method disclosed by the invention (according to the processing method in embodiment 3), the other specimen is subjected to metagenomic sequencing, 20Mb reads are measured, and 12 CPUs are adopted for metagenomic calculation and analysis. And finally comparing the detection period difference between the gene chip detection and the metagenome sequencing gene detection.
The results are shown in Table 8:
TABLE 8 comparison table of timeliness of gene chip detection method and metagenome sequencing gene detection
Figure BDA0003234653900000202
Figure BDA0003234653900000211
As can be seen from Table 8, the complete flow of the metagenome sequencing gene detection method takes 26h, while the detection by using the gene chip only needs 10h, and the period is shortened by 2.5 times. In addition, the data analysis and report reading based on the gene chip are simpler than the metagenome sequencing gene detection method, so the application threshold is lower, and the effect of the potential pathogenic parasites in the sample to be detected can be detected more quickly.
EXAMPLE 5 accuracy of the method for detecting parasites by Gene chip
In order to verify the accuracy of the method for detecting parasites using the gene chip in example 3 of the present invention, the inventors collected 5 cerebrospinal fluid specimens (samples 1-5) indicating the occurrence of food-borne pathogenic parasite infection in both clinical diagnosis and PCR detection results, and collected 1 saliva sample (sample 6) of healthy persons as a negative control. All the specimens were divided into two, and 1 specimen was examined by the gene chip examination method of example 3; and the other part is subjected to a metagenome sequencing gene detection and analysis method for detection. And comparing the difference of the detection results of the gene chip detection method and the metagenome sequencing gene detection method.
The detection method of the gene chip described in example 3 was used to detect the nucleic acid, total amount of nucleic acid, specific activity of fluorescent label, and quality of signal data, all of which passed the standards, and thus the subsequent data analysis and result determination were performed. The results are shown in Table 9:
comparison of pathogen detection between the Gene chip detection method of Table 9 and the metagenome sequencing Gene detection method
Sample(s) Clinical diagnosis + PCR results Gene chip Metagenomic sequencing
Sample
1 Angiostrongylus cantonensis + +
Sample 2 Toxoplasma gondii + -
Sample 3 Toxoplasma gondii + +
Sample 4 Angiostrongylus cantonensis + +
Sample 5 Taenia solium + +
Sample 6 - - -
Note: + indicates detection (positive); -means no detection/finding (negative)
As can be seen from Table 9, the detection sensitivity and specificity of the gene chip are both 100%, while the specificity of the metagenomic sequencing is 100%, but the sensitivity is only 80% (4/5).
The results show that the specific probe designed by the invention is more sensitive to detect 4 food-borne pathogenic parasites, and is particularly suitable for the condition of low pathogenic microorganism carrying capacity. In addition, the gene chip of the invention can accurately detect 4 parasites causing food-borne diseases, has excellent sensitivity and specificity, and can be used for rapidly screening food-borne pathogenic parasites.
All documents referred to herein are incorporated by reference into this application as if each were individually incorporated by reference. Furthermore, it should be understood that various changes and modifications of the present invention can be made by those skilled in the art after reading the above teachings of the present invention, and these equivalents also fall within the scope of the present invention as defined by the appended claims.
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Claims (10)

1. A method for designing a probe for detecting pathogenic microorganisms is characterized by comprising the following steps:
s1, obtaining a reference genome sequence of the pathogenic microorganism;
s2, breaking the obtained reference genome sequence into a 50nt k-mer set, firstly, aligning the k-mer set to a ginseng reference genome sequence hg19, and filtering k-mers with identity greater than or equal to 85; then comparing the k-mer set of the pathogenic microorganism with 50nt k-mer sets interrupted by other pathogenic microorganisms by the same method pairwise, filtering probes with the number of continuously compared bases being more than 20nt, screening out an initial specific probe sequence set of the pathogenic microorganism, and counting the abundance of the probe sequence;
s3, filtering the initial specific probe sequence set:
s31, comparing the probe sequences in the initial specific probe sequence set with RefSeq nucleic acid databases of other pathogenic microorganisms, if the comparison length is more than 20nt, calculating the nucleic acid free energy of the probe sequences and the target sequences, and if the nucleic acid free energy is less than-30, removing the probe sequences;
s32, if the same continuous basic group of the probe appears for 5 times, removing the probe sequence;
and S4, reserving the first N probe sequences with the highest abundance from the rest probe sequences as the probe sequences of the pathogenic microorganisms, wherein N is 1-50.
2. The method of claim 1, where the pathogenic microorganism is selected from at least one of a bacterium, a virus, a fungus, and a parasite.
3. The method of claim 1, wherein probes for a plurality of pathogenic microorganisms are designed simultaneously, and in step S1, reference genomes for the plurality of pathogenic microorganisms are obtained.
4. The method of claim 3, wherein when designing probes for a pathogenic microorganism, the reference genome sequences of other pathogenic microorganisms in the pathogenic microorganisms are broken into 18nt k-mer sets, and after step S2 and before step S3, the obtained probes are respectively subjected to sequence alignment with the 18ntk-mer sequence sets, and if the identity of a probe aligned with at least one sequence in the 18nt k-mer sets is greater than or equal to 85 in the sequence alignment result, the probe sequence is removed.
5. A probe designing apparatus for detecting a pathogenic microorganism, characterized in that it is capable of carrying out the probe designing method for detecting a pathogenic microorganism according to any one of claims 1 to 4.
6. A probe set for detecting at least two of 4 food-borne pathogenic parasites selected from the group consisting of Angiostrongylus cantonensis, Cryptosporidium parvum, Toxoplasma gondii and Taenia solium, wherein the probes for detecting the 4 food-borne pathogenic parasites are designed by the method of any one of claims 1 to 4.
7. The probe combination according to claim 6, wherein the probe for detecting angiostrongylus cantonensis comprises at least one of the probes consisting of the nucleotide sequences shown in SEQ ID Nos. 1 to 6; the probe for detecting the cryptosporidium parvum comprises at least one of probes respectively consisting of nucleotide sequences shown in SEQ ID No. 7-12; the probe for detecting the taenia solium comprises at least one of probes respectively composed of nucleotide sequences shown by SEQID Nos. 19-24; the probes for detecting Toxoplasma gondii comprise at least one of the probes respectively consisting of nucleotide sequences shown in SEQ ID No. 13-18.
8. A gene chip, which is characterized in that the gene chip comprises the probe combination of claim 6 or 7, preferably, the probe combination further comprises a negative control probe, a positive control probe and/or a global quality control probe.
9. A kit, characterized in that the kit comprises the probe combination of any one of claims 6 to 7 or the gene chip of claim 8, and preferably, the kit further comprises a genomic DNA extraction reagent, a nucleic acid amplification reagent, a fluorescence labeling reagent and/or a purification reagent of a sample to be detected.
10. A method of detecting a food-borne pathogenic parasite comprising the steps of:
s1, obtaining the genome DNA of the sample to be detected;
s2, performing nucleic acid amplification, fluorescence labeling and purification on the obtained genome DNA;
s3, performing hybridization detection using the gene chip of claim 8;
and S4, judging the detection result according to the detected probe signal.
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