1. The gene sequence of the resistance gene of chloramphenicol is shown in SEQ ID No.1 and is named as ykKD _ like gene.

Use of an inhibitor of ykD _ like gene expression in the preparation of a product for reducing resistance of a subject to chloramphenicol.

3. Application of a reagent for detecting a SEQ ID No.1 sequence in preparing a kit for detecting chloramphenicol drug resistance.

4. The use of claim 4, wherein the reagent for detecting the sequence of SEQ ID No.1 is a reagent constructed by performing qualitative or quantitative detection on the sequence of SEQ ID No.1 by a PCR method.

Use of the ykD _ like gene as a target gene for increasing the sensitivity of a subject to chloramphenicol.

6. The use according to any one of claims 2 to 5, wherein the chloramphenicol resistance is resistance to chloramphenicol in gram-positive and gram-negative bacteria.

7. A method for detecting chloramphenicol resistance is characterized in that the chloramphenicol resistance is detected based on SEQ ID No.1 sequence information.

8. The method of claim 7, wherein the method is not for diagnostic purposes.

9. The method of claim 7, wherein the chloramphenicol resistance is resistance to chloramphenicol in gram-positive and gram-negative bacteria.

Background

The chloramphenicol antibiotic is a broad-spectrum antibiotic separated and extracted from streptomyces, and has good inhibitory effect on a plurality of gram-positive bacteria, gram-negative bacteria and the like. The action mechanism is mainly that the action of the peptide-transferase is blocked by combining with the 50S subunit of the ribosome, thereby influencing the extension of a peptide chain and inhibiting the formation of protein.

Hidden Markov Models (HMM) based on probability can determine implicit parameters of the process from observable parameters, are often used for supplementing gene annotation and gene prediction in the field of research of Antibiotic Resistance Genes (ARGs), and have potential for developing potential novel genes. Traditional gene annotation is usually set by means of a threshold value of sequence similarity, but the method limits the discovery of novel genes and has certain limitation on the annotation of ARGs. The HMM model-based database widely applied at home and abroad comprises Pfam, TIGERFAM, Resfam and the like, and plays a vital role in comprehensively analyzing and mining the ARGs.

The ARGs-OAP is an online ARGs analysis platform, can realize the rapid annotation and quantification of the ARGs of metagenome data, and the database (Structured biological Resistance genes, SARG) contained in the ARGs-OAP integrates two large ARGs databases, namely ARDB and CARD, and lays a solid foundation for the comprehensive analysis of the ARGs by classifying and annotating the ARGs sequences step by step. On the basis of an SARG database, the platform establishes a database SARGfam based on model comparison by applying an HMM model construction method, and can be used for developing potential novel resistance genes.

Disclosure of Invention

Against the background described above, the present invention aims to provide a chloramphenicol resistance gene and its use. The invention discovers a novel resistance gene ykkkD _ like of chloramphenicol from a strain of Caballeronia (without corresponding Chinese name), supplements a chloramphenicol drug resistance database, and lays a solid foundation for further research on bacterial drug resistance.

In order to achieve the purpose, the invention adopts the technical scheme that:

the first aspect of the invention provides a chloramphenicol resistance gene, the gene sequence of which is shown in SEQ ID No.1 and is named ykD _ like gene.

The second aspect of the invention provides the application of the ykD _ like gene expression inhibitor in preparing a product for reducing the resistance of a subject to chloramphenicol.

The third aspect of the invention is the application of the reagent for detecting the SEQ ID No.1 sequence in the preparation of a kit for detecting the drug resistance of chloramphenicol, and further, the reagent for detecting the SEQ ID No.1 sequence is constructed by qualitatively or quantitatively detecting the SEQ ID No.1 sequence by a PCR method.

The fourth aspect of the invention is to provide the application of the ykD _ like gene as a target gene in improving the sensitivity of a subject to chloramphenicol.

The fifth aspect of the invention provides application of the ykD _ like gene in preparing a kit for evaluating chloramphenicol resistance.

The sixth aspect of the invention is to provide a method for detecting chloramphenicol resistance, further, chloramphenicol resistance is detected based on the sequence information of SEQ ID No.1, which is not for diagnostic purposes.

In the technical scheme of the invention, the chloramphenicol resistance refers to the resistance of gram-positive bacteria and gram-negative bacteria to chloramphenicol.

The technical scheme has the following advantages or beneficial effects:

the invention provides a novel resistance gene ykD _ like gene of chloramphenicol and application thereof, wherein the sequence of the ykD _ like gene is shown in SEQ ID No. 1. Through sequence similarity alignment, no known resistance gene is found on the genome. The invention provides help for understanding the drug resistance mechanism of chloramphenicol and supplementing a drug resistance database, provides theoretical support for subsequent chloramphenicol resistance, provides a target for solving chloramphenicol resistance, and lays a foundation for research on antibacterial resistance.

Drawings

FIG. 1 is a phylogenetic tree diagram between the ykD _ like gene and a known reference gene sequence in example 1, which is used to describe the degree of difference between the ykD _ like gene sequence and the known reference sequence.

Detailed Description

The following examples are only a part of the present invention, and not all of them. Thus, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the invention without making creative efforts, belong to the protection scope of the invention.

Example 1:

1. prediction of Open Reading Frame (ORF) of genome

And (3) applying prodigal software to perform ORF prediction on the pure bacterial genome obtained by subpackaging to obtain an ORF file of the genome.

2. HMM-based model alignment

And (3) comparing the ORF file obtained in the step (1) with a SARGfam database by using a hmmmscan function in HMMER software (parameter setting: -cut _ ga-tblout) to obtain an ORF annotation result based on model comparison. The alignment results are shown in Table 1.

TABLE 1

Target name	Query id	E-value	sore	Bias
					ykkD_train_msa	CL5.1_1_482	1.3e-19	64.0	4.3

3. Sequence similarity based alignment

And (3) comparing the ORF file obtained in the step (1) with a SARG database by using blastp (parameter setting: evalue 1e-10-max _ target _ seqs 1), and obtaining an ORF annotation result based on sequence similarity. The alignment results are shown in Table 2.

TABLE 2

Query id	identity	coverage	Annotation
				CL5.1_1_482	39.60	0.96	ykkD

4. Identification of potentially novel resistance genes

(ii) defining as true the annotation result for the ORF with sequence similarity higher than 70% and coverage higher than 65% in the result of step 3, i.e. known ARGs, whereas an ORF not meeting the threshold is defined as a potential novel gene if there is an annotation result in step 2; if an ORF is not annotated as ARG after alignment based on sequence similarity, but is annotated as ARG in the alignment results of HMM model, the ORF is also considered as a potential novel gene. Through screening, the potential novel chloramphenicol resistance gene in the pure bacterium genome is found to be ykkkD _ like. The reference sequence corresponding to the ykD gene in the SARG database and the gene sequence of ykD _ like are subjected to multiple sequence alignment by using ClustalW, a maximum likelihood phylogenetic tree is constructed by using MEGA, the topological structure of the tree is evaluated by resampling 1000 times by using a bootstrap method, and the difference degree between the potential novel gene ykD _ like and the known reference gene sequence is further determined (as shown in figure 1).

Example 2

The strain containing the ykD _ like gene is purified and separated, and after the MIC value of the strain is detected to the Minimum Inhibitory Concentration (MIC) of the strain to chloramphenicol, the MIC value of the strain to chloramphenicol is as high as 120mg/L, which indicates that the ykD _ like gene makes the strain resistant to chloramphenicol, and the ykD _ like gene is a drug-resistant gene of chloramphenicol.

The above description is only for the preferred embodiment of the present invention and is not intended to limit the scope of the present invention, and all equivalent modifications made by the contents of the present specification and the drawings, or applied directly or indirectly to other related technical fields, are included in the scope of the present invention.

SEQUENCE LISTING

<110> Shenzhen International institute for graduate of Qinghua university

Novel ykkkKD resistance gene of <120> chloramphenicol and application thereof

<130> CP121010590C

<160> 1

<170> PatentIn version 3.3

<210> 1

<211> 312

<212> DNA

<213> Caballeronia

<400> 1

atggcatggg tactacttag cctggcaggc gtgcttgaga tcgctttcgc ctttgcgatg 60

aaggcctcag acggcttcac gcgactgacg cccgggctgc ttacggtcgc gagcggactg 120

tcgagcgtga ttctgctctc cgtggcgctc cggacagtgc cggtcgggac cggctacgcc 180

gtgtggactg gaatcggggc ggcgggtacg gcaattcttg gtatcgcttt gctcggagat 240

tcggccgcac cattgcgggt gtttttcatc ctgctgattc tcggtggcgt gatcggactc 300

aagttcgcat ag 312