1639 results about "Gene sequence" patented technology

The invention relates to the technical field of genomics, in particular to a gene detection data cleaning method and system based on artificial intelligence. The method comprises the following steps: acquiring gene detection data, and performing preliminary filtering on the gene detection data based on removal of low-quality reads to obtain preliminary filtering data; performing linker sequence identification and removal on the preliminarily filtered data, and performing sequencing error correction to generate gene sequence data; performing GC content analysis and repetitive sequence identification on the gene sequence data to obtain sequence feature data; performing dynamic quality threshold adjustment according to the sequence feature data, and performing secondary filtering on the gene sequence data to generate high-quality sequence data; and performing sequence pattern recognition on the high-quality sequence data to obtain sequence pattern feature data. According to the method, deep analysis is carried out by utilizing sequence characteristics such as GC content and nucleotide distribution, and the recognition capability on sequence complexity and variation modes is improved.

The invention discloses a long-chain non-coding RNA molecular marker related to bovine semen quality and application of the long-chain non-coding RNA molecular marker, long-chain non-coding RNA comprises an LNC68393 promoter sequence and an LNC68393 gene sequence, a molecular marker SNP1 is located on the promoter sequence, and a molecular marker SNP2-5 is located on the gene sequence. Different polymorphisms of the molecular marker are significantly related to the bull semen quality, and the molecular marker can be applied to detection of the bull semen quality, further early evaluation of the bull reproductive performance, cultivation of excellent bulls, shortening of the breeding time, improvement of the efficiency and reduction of the cost, and has important application value in improvement of the reproductive performance of the whole bull herd.

The invention discloses a gene PbrbHLH195 for regulating and controlling synthesis of pear fruit lignin. The CDS (Coding Sequence) of the gene is shown as SEQ ID NO. 1. An overexpression vector constructed by the gene is injected into a Dangshan pear fruit, and compared with an uninjected part and an injected no-load control GFP (Green Fluorescent Protein), the contents of stone cells and lignin are obviously increased; an overexpression vector constructed by the gene is introduced into arabidopsis thaliana, secondary cell walls of conduit cells and intervascular bundle fiber cells of the obtained PbrbHLH195 transgenic arabidopsis thaliana are remarkably thickened, accumulation of lignin in stems is increased, and the expression quantity of lignin biosynthesis related genes is remarkably increased. The discovery of the gene provides a new gene resource for fruit quality breeding, and the gene is an important candidate gene for improving fruit quality breeding in future genetic engineering.

The invention relates to the technical field of intelligent control, in particular to an intelligent electric cooker control method and system based on the Internet of Things, and the method comprises the steps: obtaining instruction information remotely sent by a user, and converting the instruction information into coded information; the method comprises the following steps: acquiring type information and weight information of food in an intelligent electric cooker, fusing the type information and the weight information of the food to obtain a plurality of gene sequences, and taking a plurality of genes in the sequences as preferable genes; randomly modifying the value of a preferred gene in a preset range, and performing fitness evaluation on the modified gene sequence in combination with the coding information until an optimal gene sequence is obtained; and converting the optimal gene sequence into a cooking control instruction, and controlling the intelligent electric cooker to perform cooking operation according to the cooking control instruction. According to the method and the device, the optimal cooking scheme is automatically generated and selected by analyzing the user instruction, identifying the type and the weight of the food materials and adopting gene sequence optimization and fitness evaluation, so that personalized and intelligent cooking experience is realized, and the use experience of the user is improved.

The invention provides a crop whole genome prediction method and system based on machine learning, and the method comprises the steps: firstly obtaining a gene expression data set of a target crop in a plurality of growth cycles, the gene expression data set containing a plurality of gene sequence samples composed of genetic markers and phenotypic character data; performing feature extraction on the gene expression data set to obtain gene association features and growth character features, performing fusion prediction on the gene association features and the growth character features by using a preset machine learning model to generate fusion prediction features, and determining a whole genome prediction result according to the fusion prediction features. The whole genome prediction result can indicate character expression trends of crops in different environments, and finally, an adaptability optimization strategy is generated based on the whole genome prediction result and fed back to a crop cultivation system, cultivation parameter adjustment is triggered, crop cultivation precision and intelligence are achieved, and the cultivation efficiency and crop adaptability are improved.

The invention relates to the technical field of gene variation detection, in particular to a gene sequence variation detection method based on robust statistics and multi-strategy fusion, which comprises the following steps: comparing to generate a sorted BAM file; preprocessing a missing value and an N position in the data, replacing the missing value by adopting a 0 filling strategy, and removing the data at the N position; extracting an RD signal and an MQ signal as characteristic values; performing GC deviation correction on the extracted RD signal; performing smooth noise reduction processing on the RD signal and the MQ signal; a two-step progressive segmentation strategy is adopted, and continuous fragments with highly consistent RD values are identified; constructing two-dimensional profiles of the RD signal and the MQ signal, and performing standardization processing; carrying out serial repeated detection and calculating an abnormal score; setting a threshold value by using a box plot method, and judging an abnormal value; and refining a tandem repeated region. According to the method, the problem of tandem repeat variation detection under low-coverage sequencing data is effectively solved, and the detection accuracy and reliability are remarkably improved.

The invention provides an intracellular mycobacterium tuberculosis in-situ nucleic acid detection method based on CRISPR / Cas and application, and the method comprises the following steps: S1, designing crRNA and a primer pair of a mycobacterium tuberculosis target gene sequence, and synthesizing a single-stranded DNA fluorescent probe; s2, preparing a standard solution containing a target gene sequence, and incubating with a CRISPR / Cas12a system; s3, extracting nucleic acids of different types of bacteria, uniformly mixing the nucleic acids of different types of bacteria with the CRISPR / Cas12a system, and incubating; s4, incubating an attenuated strain of mycobacterium tuberculosis and the DNA fluorescent probe, infecting macrophages, and incubating to obtain infected cells; s5, electrically transferring a CRISPR / Cas12a system into the infected cells in S4 by utilizing an electroporation technology, incubating, and detecting the intensity of a fluorescence signal; and S6, performing quantitative and positioning analysis on the detected fluorescence signal to complete detection, and directly introducing a CRISPR / Cas12a system into the macrophage by adopting an electroporation technology to realize intracellular in-situ detection, thereby avoiding the operation complexity of a nucleic acid extraction link and the loss of detection sensitivity in the prior art.

The invention belongs to the technical field of molecular genetic breeding, and particularly relates to a molecular marker Zm00001eb181850 gene related to corn leukoderma resistance and application thereof, the invention provides a molecular marker related to the corn leukoderma resistance, the gene sequence of the molecular marker is shown as SEQ ID NO: 1 and / or SEQ ID NO: 2, and the molecular marker Zm00001eb181850 gene is shown as SEQ ID NO: 1 and / or SEQ ID NO: 2. Researches prove that corn white spot resistance QTL qMWS4-1 and qMWS4-5 intervals and resistance SNP: 4-118983592 have co-localization, the corn white spot resistance QTL has a high phenotypic interpretation rate, the associated gene Zm00001eb181850 (SEQ ID NO: 2) is highly expressed in corn leaves, it is proved that the associated gene Zm00001eb181850 (SEQ ID NO: 2) is associated with the corn leaf spot, the corn white spot resistance is a quantitative character jointly regulated by multiple genes, and the corn leaf spot resistance QTL has a good application prospect. According to the technical scheme provided by the invention, a new method is provided for cultivating a new variety of leukoderma-resistant corn by utilizing a modern molecular breeding technology.

The invention belongs to the technical field of biology, and particularly relates to a latex duplex immunochromatography test strip for rapidly identifying a porcine transmissible gastroenteritis virus (TGEV) and a porcine epidemic diarrhea virus (PEDV) and a preparation method of the latex duplex immunochromatography test strip. Soluble TGEV N protein and PEDV N protein with immunogenicity and reactivity are respectively obtained by utilizing a prokaryotic expression system, the soluble TGEV N protein and the soluble PEDV N protein are used as immunogenicity to immunize mice, and specific monoclonal antibodies of the TGEV N protein and the PEDV N protein are respectively obtained by utilizing cell fusion and subcloning screening technologies. The antibody variable region gene sequence is obtained by using a nested PCR amplification technology, and can be subsequently obtained by using a gene engineering or protein engineering method. Then, the latex duplex immunochromatography test strip for detecting TGEV and PEDV, which is convenient, rapid and high in sensitivity, and the preparation method are researched and developed on the basis of specific monoclonal antibodies of TGEV N protein and PEDV N protein.

The invention provides an indoxacarb degrading enzyme as well as a coding gene, a production strain and application thereof. Wherein the amino acid sequence of the indoxacarb degrading enzyme is as shown in SEQ ID NO. 1, and the sequence of the coding gene is as shown in SEQ ID NO. 2. The production strain is a recombinant engineering strain comprising the coding gene. The application refers to the application of the indoxacarb degrading enzyme in degrading indoxacarb and repairing an indoxacarb polluted environment, and a corresponding method for degrading indoxacarb or repairing the indoxacarb polluted environment. The indoxacarb degrading enzyme has the advantages that the screened indoxacarb degrading enzyme can efficiently and rapidly degrade indoxacarb, can also be used for repairing environments such as water bodies and soil polluted by indoxacarb, and has important application value.

The invention relates to the technical field of gene engineering, in particular to a cat serum albumin preparation and characterization method. The cat serum albumin gene sequence is optimized, a recombinant expression vector is successfully constructed, pichia pastoris genetically engineered bacteria are prepared, high-yield expression of the cat serum albumin gene in pichia pastoris is achieved, a purification system is established and perfected, and a pure product with the purity larger than 98% is obtained through affinity exchange column purification. Compared with the natural cat serum albumin, the cat serum albumin has a secondary structure, stability and antioxidant activity which are consistent with those of the natural cat serum albumin, has the characteristic of low hemolytic activity, can realize large-scale efficient production, can be applied to development of pet foods and medicines, and has wide application value and market prospect.

The invention provides a lentivirus for treating cancer as well as a preparation method, application and a corresponding pharmaceutical composition of the lentivirus. According to the invention, an hTERT promoter and a CDC6shRNA gene sequence are inserted behind an enzyme cutting site of a vector, an obtained plasmid is transferred into an expression strain, the expression strain is cultured and screened to obtain a cloned strain, and the cloned strain is shaken and packaged to obtain the hTERT-CDC6shRNA lentivirus; when the lentivirus disclosed by the invention is used for infecting cancer cells, the experimental result shows that the proliferation of the cancer cells can be effectively inhibited.

The invention provides a molecular marker for detecting pepper light mottle virus L-series resistance genes and application of the molecular marker, and belongs to the technical field of genetic engineering, the molecular marker comprises SNP1 and SNP2, the SNP1 is a base T at the 2574th site of a yellow lantern pepper genome sequence with the NCBI login number of AB523370, and the SNP2 is a base T at the 2832nd site of the yellow lantern pepper genome sequence with the NCBI login number of AB523370; the specific gene sequence is a specific gene sequence of an L-series resistance gene L1c type gene, and the specific gene sequence is a basic group CA at the 2872 site to the 2873 site, a basic group TT at the 2877 site to the 2878 site, a basic group TG at the 2882 site to the 2883 site and a basic group AGA at the 2885 site to the 2887 site of the yellow lantern pepper with the NCBI accession number being AB523374. By utilizing the molecular marker and the specific sequence, the L-series resistance gene types of the yellow lantern pepper and the annual pepper can be rapidly and accurately detected, and the molecular marker can be used for molecular marker-assisted selective breeding.

The invention discloses a preparation method of a recombinant engineering bacterium for expressing XVII type collagen COL17A1, and relates to the technical field of gene engineering, in particular to a preparation method of a recombinant engineering bacterium for expressing XVII type collagen COL17A1, which comprises the following steps: gene synthesis and vector construction: synthesizing an optimized sequence SEQ ID No.1 of human source XVII type collagen COL17A1; adding proper restriction enzyme cutting sites at two ends of the sequence; the synthesized gene sequence is cloned to a pGAPZ A-alpha A vector, and the expression of the gene under the control of a GAP promoter is ensured. According to the preparation method of the recombinant engineering bacterium for expressing the XVII type collagen COL17A1, by using a GAP promoter, the constructed recombinant engineering bacterium can keep a stable expression level under different environmental conditions, the GAP promoter serving as a constitutive promoter can continuously and stably express recombinant protein in pichia pastoris, an inducer does not need to be added, the production process is simplified, and the production cost is reduced. The production cost is reduced, and the production efficiency is improved.

The invention relates to screening and application of a Candida antarctica lipase B mutant. Specifically, the Candida antarctica lipase B mutant provided by the invention is obtained by carrying out rational design and directed evolution combined strategy mutation on the basis of a wild Candida antarctica lipase B gene sequence, and the amino acid sequence of the mutant is shown as SEQ ID NO.3. The invention also relates to a preparation method of the Candida antarctica lipase B mutant. The mutant has higher enzyme activity and thermal stability, the hydrolytic catalytic activity of the mutant is improved to 2.1 times of the original hydrolytic catalytic activity, and the half-life period of the mutant enzyme at 50 DEG C is prolonged by 4 times. On the basis, pichia pastoris is used as a host to express the mutant, and a strain with hydrolytic activity improved by 52% is obtained through high resistance screening. The lipase is prepared into an immobilized enzyme to be used in a synthetic reaction of chlorogenic acid derivatives, the highest conversion rate of chlorogenic acid reaches 74% in 24 hours, and the immobilized enzyme has a good industrial application prospect.

The application provides a novel DNA methylation marker TAGMe-3 for tumor identification and use thereof. The TAGMe-3 gene sequence region has significant methylation difference between cancer tissues and paracancer tissues. As long as abnormal high methylation state of the TAGMe-3 gene sequence region is detected, the subject is determined to belong to a tumor high-risk population. Moreover, the significant difference of the TAGMe-3 presented between tumor tissues and non-tumor tissues exists in different types of tumors (Pan-cancer) in a wide range.

The present application relates to a virus of reverse genetic operation construction of NADC34-like PRRSV2. Specifically, the full gene sequence of NADC34-like PRRSV2 BJ1805-2 isolated strain is segmented and connected to the vector by using PCR amplification, enzyme digestion and other methods with pACY177 plasmid as the carrier, and the BJ1805-2 full-length infectious clone recombinant plasmid (rBJ1805-2) is obtained. The infectious clone virus rBJ1805-2 is rescued in vitro, and the first NADC34-like PRRSV2 strain infectious clone platform in China is successfully built. The present application also relates to a modification method for constructing NADC34-like PRRSV2 strain which can adapt to Marc-145 cell passage culture. The infectious clone virus constructed by the present application has good in vitro and in vivo proliferation efficiency, and can cause specific viremia after inoculation in pigs; it has good safety, does not cause fever after inoculation in pigs, and will not cause piglet death. The modified strain can be used as a candidate strain for developing the first NADC34-like PRRSV2 specific vaccine in China, and is conducive to the prevention and control of PRRSV epidemic in China.

The invention provides a chlamydomonas reinhardtii ABC transporter protein gene CrABCG as well as an encoding protein and application thereof. The chlamydomonas reinhardtii ABC transporter protein gene comprises CrABCG3 or CrABCG5, and the encoding protein of the chlamydomonas reinhardtii ABC transporter protein gene CrABCG is an ABC transporter protein The gene sequence is shown as SEQ ID NO: 1 or SEQ ID NO: 2. The invention finds that the CrABCG protein is related to carbon and nitrogen metabolism of chlamydomonas reinhardtii, preliminary research shows that the expression of the CrABCG3 gene of the chlamydomonas reinhardtii is improved after nitrogen limitation, the expression of the CrABCG5 gene is reduced and then improved, and the result shows that the CrABCG protein affects the transport, synthesis and accumulation of lipid substances. Therefore, an engineering algal strain with high lipid content can be obtained by screening and transforming the algal strain with high expression of the CrABCG gene.

The invention discloses L-arabinose isomerase, engineering bacteria and application, the amino acid sequence of the L-arabinose isomerase is shown as SEQ ID NO: 3, and the gene sequence for coding the L-arabinose isomerase is shown as SEQ ID NO: 2. On the basis of a genome of a Peribacillussp.S4 strain, a gene for coding the L-arabinose isomerase is excavated, and a stable prokaryotic expression system is constructed by performing codon optimization on the gene, so that the large-scale controllable production of the L-arabinose isomerase is realized, the yield of the enzyme is remarkably increased, the production cost of the enzyme is reduced, and the method is suitable for industrial production. A stable and economical enzyme source is provided for the production of D-tagatose; the L-arabinose isomerase expressed by the constructed engineering bacteria can significantly improve the yield of D-tagatose, and industrialization of D-tagatose is facilitated.

The invention discloses a bacillus thuringiensis L3 and an application thereof. The preservation number of the bacillus thuringiensis L3 is CCTCC (China Center for Type Culture Collection) NO: M 2025487. The gene sequence of the 16S rDNA of the bacillus thuringiensis L3 is as shown in SEQ ID NO: 1. Under different adversity stress conditions, the bacillus thuringiensis L3 shows a certain stress resistance potential. Research finds that the bacillus thuringiensis L3 has certain acid resistance, high temperature resistance, cholate resistance and drought resistance, and has strong alkali resistance.

The invention provides a subunit fusion protein RBD-Fc on the surface of a porcine D-type coronavirus and a preparation method and application thereof, the preparation method comprises the following steps: 1) cloning a gene sequence as shown in SEQ ID NO.5 into a eukaryotic expression vector to obtain a recombinant plasmid containing a fusion protein RBD-Fc coding gene; (2) transfecting a recombinant plasmid containing the fusion protein RBD-Fc coding gene into an expression cell; 3) culturing, screening and domesticating the expression cells in the step 2) to obtain a highly expressed cell strain; and 4) fermenting and culturing the cell strain in the step 3), and purifying to obtain the subunit fusion protein RBD-Fc. According to the present invention, the RBD-Fc can be subjected to mass soluble expression, the protein is stable, the problems that the porcine D-coronavirus surface S protein cannot be subjected to large-scale expression and the like in the prior art are solved, the preparation method is simple, and the cost is low.

The application discloses an NLR plug-in gene for improving plant disease resistance and application thereof, and belongs to the field of plant molecular biology and biotechnology.The NLR plug-in gene StEM1 has a whole gene sequence as shown in SEQ ID NO.1 and a CDS sequence as shown in SEQ ID NO.2, and the amino acid sequence of the encoded protein is as shown in SEQ ID NO.3.The gene plays a key role in improving plant disease resistance, especially resistance to field late blight variant bacteria.In the NLR background, overexpression of the gene significantly promotes the disease resistance of tobacco and potato to pathogenic pythium, and the gene is a gene for enhancing plant disease resistance by improving ETI immunity.Overexpression of the gene in the NLR background is obtained by a genetic transformation method, and a strain line is obtained to resist field variant strains, so as to cope with field diseases of crops.The application provides an excellent gene resource for green prevention and control of late blight and disease-resistant genetic engineering breeding.

The invention belongs to the technical field of essential gene prediction, and particularly relates to an essential gene prediction method based on DNA large model and time-frequency domain deep learning fusion, and the method comprises the steps: taking a domain DNA large model as a core representation layer, and obtaining special gene representation through cross-species corpus pre-training and task fine tuning; a T-Block and F-Block dual-channel time-frequency fusion structure is adopted, and the local dependence and long-range regulation relation of a gene sequence is synchronously captured by expanding DFT (Discrete Fourier Transform), complex value attention and iDFT (Initial Discrete Fourier Transform) conversion; designing an efficient modeling reasoning scheme of sliding window slices and gene-level aggregation aiming at an ultra-long sequence; in combination with class imbalance and a noise robust training strategy, cross-cell line / cross-platform transferable threshold output is realized through temperature scaling calibration, an uncertainty quantization and structured interface is matched, and drug target screening and experimental design decision are supported. The system supports the realization of multiple programming languages, and can complete low-delay end-to-end reasoning in a conventional hardware environment.

Processes that determine transcriptional regulation from genetic sequence data are described. Generally, computational models are trained to predict transcriptional regulatory effects, which can be used in several downstream applications. Various methods further develop research tools, develop and perform diagnostics, and treat individuals based on identified variants.

The invention relates to a mytilus coruscus byssus adhesion protein gene Mfp5 coding region SNP marker and application thereof, the mytilus coruscus byssus adhesion protein gene Mfp5 coding region SNP marker comprises a gene sequence numbered as an McMfp5 coding region, the nucleotide sequence of the gene sequence is shown as SEQ ID No.1, an SNP marker primer pair is designed based on the sequence, three SNP markers numbered as McMfp51, McMfp52 and McMfp53 are obtained through sequencing, and the primer sequences of the three SNP markers are shown as SEQ ID No.2 and SEQ ID No.3 in sequence. The primer designed aiming at the gene sequence of the McMfp5 coding region is used for SNP (Single Nucleotide Polymorphism) marker typing, is high in specificity, stable in amplification and high in polymorphism, can be used for genetic diversity analysis, germplasm identification and marker-assisted selection breeding of mytilus coruscus populations, and provides a powerful tool for genetic breeding of mytilus coruscus.

The invention provides a structure, a sequence and a construction method of a plant virus gene editing vector and application of the plant virus gene editing vector in plant gene editing. The method is characterized in that a TRV2 genome of a tobacco embrittlement virus (TRV) is used for carrying and expressing a small Cas gene AsCas12f and gRNA of the small Cas gene AsCas12f. Preferably, the AsCas12f and the gRNA of the AsCas12f are subjected to tandem expression by utilizing the TRV2 to form an expression cassette structure of the AsCas12f-tRNA-gRNA, the expression cassette substitutes a part of 2b gene sequence of the TRV2 on a TRV2 genome to form a plant gene editing vector pTRV2-Cas12f-gRNA based on the TRV virus, and long-time stable expression and gene editing can be performed after wild type nicotiana benthamiana is inoculated. The invention also provides a method for carrying out gene editing in a wild type plant by utilizing the plant virus.

The invention discloses a pCAMBIA1300-mini RNA3-BC-NLPPya vector as well as a construction method and application of the pCAMBIA1300-mini RNA3-BC-NLPPya vector in high cucumber mosaic virus resistance, the vector is characterized in that mini RNA3-BC-NLPPya is constructed to a pCAMBIA1300 vector skeleton, and the gene sequences of mini RNA3-BC and NLPPya are as shown in SEQ ID NO: 2 and SEQ ID NO: 5. The invention finds that the miniRNA3-BC-NLPPya can efficiently inhibit the infection of the CMV and effectively weaken the harm caused by the CMV, does not need to apply any medicine, is an efficient and green disease-resistant technology, and can provide a new strategy for preventing and controlling the cucumber mosaic virus and similar viruses thereof.

The invention provides a full-length gene sequence modeling method and system based on a neural network, and the method comprises the steps: constructing a first expression matrix for initial single-cell RNA sequencing data, and carrying out the quality control transformation of the first expression matrix to obtain a second expression matrix; inputting the second expression matrix into a preset binning embedding module to obtain a binning embedding matrix; maintaining and loading a gene pathway set through a knowledge base and a mapping module to obtain a binary mask matrix, and performing mask processing on the binning embedded matrix based on the binary mask matrix to obtain a pathway mask matrix; the path mask matrix is input into a preset attention state space model, the attention state space model comprises an encoder module, a jump connection module and a decoder module which are arranged in sequence, and a reconstruction tensor is output through the decoder module. According to the scheme, an efficient and extensible whole-gene annotation method is provided, and whole-gene expression input can be processed while the calculation efficiency is kept.

The invention discloses a gene sequencing sample data matching method based on a micro-fluidic chip, relates to the technical field of gene sequencing sample matching, and aims to solve the problem that the matching rate is reduced due to inaccurate analysis of gene sequencing samples. According to the method, multi-strategy comparison and candidate set screening are adopted, multi-dimensional comparison of sequences, variation and functions is combined, the accuracy is improved, the adaptability to complex samples is enhanced through quantitative index and biological verification evaluation and dynamic optimization of comparison strategies, the matching reliability and practical value are remarkably improved, the clinical and scientific research diversified requirements are met, and the method is worthy of popularization and application. Sample types such as blood and cells are adapted through a differential lysis strategy, impurities such as proteins and salts are removed through stepped purification, and the nucleic acid concentration and the fragment state are unified in combination with standardized treatment, so that interference is reduced from the source.

The invention belongs to the technical field of crop breeding, and particularly relates to a method for obtaining a tobacco variety for preventing and controlling tobacco mosaic disease, manual intervention mutation is carried out by using the 120th to 142 basic groups of a tobacco NtFd gene shown as SEQ ID NO.1, and the sequence of a mutated nucleotide fragment is shown as SEQ ID NO.2. The ntfd editing strain obtained on the basis of manual intervention mutation of the NtFd gene sequence shows a remarkable effect of preventing and controlling the tobacco common mosaic disease, and a gene resource and a material basis are provided for cultivation of a tobacco disease-resistant strain.