74 results about "Streptococcus mastitidis" patented technology

The invention provides an SNP (Single Nucleotide Polymorphism) site combination for identifying streptococcicosis resistance of tilapia and application of the SNP site combination. DNAs of tilapia tail fin tissues attacked by streptococcus agalactiae are re-sequenced, resistant and sensitive individuals of a tilapia population are screened, GWAS analysis is carried out, SNPs sites related to tilapia streptococcus agalactiae disease resistance are identified, functional gene annotation and enrichment analysis are carried out, two SNP sites LG1320881657 and LG1320548718 are screened, and the SNP sites related to tilapia streptococcus agalactiae disease resistance are obtained. The GG genotype of the LG1320881657 and the TT genotype of the LG1320548718 are the dominant genotypes related to the streptococcus agalactiae disease resistance of the tilapia mossambica. The tilapia mossambica resistant to streptococcosis is successfully screened by utilizing the two SNPs sites, effective SNPs are provided for developing tilapia mossambica anti-streptococcosis molecular marker-assisted breeding, excellent characters of parents are ensured, and the breeding efficiency is improved.

The invention discloses application of polypeptide compounds in prevention and treatment of pathogenic microorganisms. The compound has a synergistic effect on agricultural fungi such as rhizoctonia solani, Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium graminearum, Pyricaria oryzae, pyricularia oryzae, pyricularia oryzae, pyricularia oryzae, pyricularia oryzae, pyricularia oryzae, pyricularia oryzae, pyricularia oryzae, pyricularia oryzae, pyricularia oryzae, pyricularia oryzae, pyricularia oryzae and pyricularia oryzae. The method comprises the following steps: carrying out sterilization on plant bacteria such as Xanthomonas oryzae PXO99A, Xanthomonas axonophora dispsp.citrijx-6, Pseudomonas solanacearum (Smith) BNCC335855, Pseudomonas sp. The method is characterized by comprising the following steps of: killing Aspergillus flavus ACCC32601 (Aspergillus flavus), Penicillium expansum ACCC 30898 (Penicillium expansum. EXPANSum ACCC 30898), Monilinia coerulea ACCC 36263 (Aspergillus oryzae, Aspergillus niger, Aspergillus niger, Aspergillus niger, Aspergillus niger, Aspergillus niger, Aspergillus niger, Aspergillus niger and Aspergillus niger); the compound disclosed by the invention has a certain inhibition activity on various diseases caused by streptococcus agalactiae ATCC 27956, streptococcus dysgalactiae ATCC27957, Escherichia coli ATCC 25922 and Staphylococcus aureus, particularly, the compound Thiostreptin has a particularly remarkable inhibition effect on agricultural pathogenic bacteria, food-borne germs and cow mastitis germs, and is expected to be developed into a novel antibacterial drug, so that the compound disclosed by the invention can be used for preparing the antibacterial agent for preventing and treating various diseases caused by the streptococcus agalactiae ATCC 27956, the streptococcus dysgalactiae ATCC27957, the Escherichia coli ATCC 25922 and the Staphylococcus aureus.

The invention discloses a rapid streptococcus agalactiae detection kit based on RPA (recombinase polymerase amplification) and CRISPR-Cas12a (clustered regularly interspaced short palindromic repeats) and application of the rapid streptococcus agalactiae detection kit. The rapid streptococcus agalactiae detection kit comprises an amplification primer of a recombinase polymerase amplification technology, CRISPR RNA (ribonucleic acid), an ssDNA (single-stranded deoxyribonucleic acid) probe and Cas12a protein Wherein an upstream primer sequence of an amplification primer of the recombinase polymerase amplification technology is as shown in SEQ ID NO: 1; and the sequence of the downstream primer is as shown in SEQ ID NO: 2. According to the invention, rapid, sensitive, accurate and specific detection of streptococcus agalactiae is realized.

The invention provides engineering lyase Art-15 with broad-spectrum antibacterial activity, antibacterial peptide NZ2114 and bacteriophage lyase PlySs2 are subjected to functional fusion through an optimally designed flexible linker, and an efficient bactericidal effect on Staphylococcus aureus (Staphylococcus aureus) and Streptococcus spp.) is achieved. The engineering lyase Art-15 has the advantages that the engineering lyase Art-15 has broad-spectrum antibacterial activity, the antibacterial peptide NZ2114 and the bacteriophage lyase PlySs2 are subjected to functional fusion through the optimally designed flexible linker, and the engineering lyase Art-15 has broad-spectrum antibacterial activity; the lyase Art-15 overcomes the defects of narrow host spectrum and insufficient splitting activity of the lyase through a synergistic destruction mechanism of targeting bacterial cell wall peptidoglycan. Experiments show that the minimal inhibitory concentration (MIC) of the lyase Art-15 on staphylococcus aureus in vitro is lower than 2 mu g / mL, the minimal inhibitory concentration of the lyase Art-15 on streptococcus agalactiae is lower than 1 mu g / mL, the minimal inhibitory concentration of the lyase Art-15 on streptococcus dysgalactiae is lower than 2 mu g / mL, and the sterilization rate of the lyase Art-15 can reach 97% or above within 30 minutes by 2 times of MIC. The lyase Art-15 disclosed by the invention has important application value in the fields of drug-resistant bacterium infection treatment, medical instrument disinfection and livestock breeding.

The invention provides application of baicalin in preparation of a medicine for treating streptococcus agalactiae induced mastitis, and relates to the technical field of medicine. A mouse is selected as an animal model to research the intervention effect and mechanism of the baicalin on the streptococcus agalactiae induced mouse mastitis inflammatory response, and it is clear that the baicalin can play a role in protecting the mouse mammary gland by regulating and controlling an NLRP3 inflammatory small body pathway; a reference basis is provided for treating the cow mastitis caused by streptococcus agalactiae infection by applying the baicalin.

The invention provides an electronic one-tube automatic detection system and a detection method for streptococcus agalactiae or gonococci, through an LAMP and CRISPR-Cas12a combined mediated one-tube visual streptococcus agalactiae or gonococci detection system, in combination with an electronic automation technology, an LAMP reaction mixture and a CRISPR-Cas12a reaction mixture are mixed to form a one-tube reaction system, and the one-tube reaction system is used for detecting the streptococcus agalactiae or gonococci. Automatic mixing, preheating reaction and fluorescence detection of various detection reagents and samples are realized, and visual display is performed on detection results by adopting visual equipment. Visual detection of bacteria is achieved by detecting fluorescence signals, rapid positive or quantity detection results can be provided for patients and other users, and clinical detection efficiency is improved.

The invention relates to the technical field of biology, in particular to a detection method for tilapia streptococcus agalactiae resistance, a KASP primer group and application. According to the invention, the key SNP site of the ABCB4 gene, which is obviously associated with the streptococcus agalactiae disease resistance, of the tilapia is identified by a population genetics method, a typing method of the SNP site is developed by a KASP technology, efficient evaluation on disease resistance characters is realized, experimental data shows that the survival time of an AA genotype individual in a challenge test is prolonged compared with that of a GA / GG genotype individual, and the survival time of the AA genotype individual in the challenge test is obviously prolonged compared with that of a GA / GG genotype individual. The proportion of resistant fishes is remarkably increased, and genotype frequency distribution is strongly related to group disease resistance. According to the breeding strategy based on the SNP marker, the disease resistance of bred groups can be integrally improved, the morbidity and death rate are reduced, an efficient genetic improvement tool is provided for breeding of tilapia mossambica for resisting streptococcus agalactiae diseases, the loss of breeding diseases is reduced, and antibiotic dependence is reduced.

The invention relates to the technical field of biology, in particular to an SNP (Single Nucleotide Polymorphism) marker combination for identifying tilapia streptococcus agalactiae disease resistance and application thereof. The invention discloses 11 SNP loci significantly related to streptococcus agalactiae resistance in a tilapia UTRN gene, and constructs 18 SNP marker combinations for streptococcus agalactiae resistance phenotype identification, so that the resistance phenotype identification accuracy and hereditary stability can be effectively improved. Besides, according to the SNP typing primer and method based on the # imgabs0 # MALDI-TOF mass spectrum platform, high-throughput and high-precision genetic typing can be achieved, and the SNP typing primer and method have important application value in resistance phenotype identification and assistant selective breeding.

The invention relates to the technical field of biology, in particular to a tilapia mossambica streptococcus agalactiae resistance related KASP molecular marker and application thereof. According to the invention, two SNP (Single Nucleotide Polymorphism) loci, namely SNP-1 and SNP-2, which are remarkably associated with resistance are screened based on an intron region of an EGFRX2 gene of tilapia mossambica, a typing method of the loci is developed through a KASP technology, and relevance between the genotype of the SNP-1 and a resistance phenotype is verified. Furthermore, streptococcus agalactiae resistance dominant diplotype individuals are screened in combination with double SNP loci, and the survival rate of a challenge experiment is remarkably improved. The detection kit provided by the invention can realize high-throughput and high-precision typing, is suitable for tilapia mossambica resistance genotype identification and molecular marker-assisted breeding, provides an efficient genetic improvement tool for tilapia mossambica disease-resistant breeding, and is beneficial to reduction of breeding disease loss and reduction of antibiotic dependence.

The invention discloses application of a licoflavone compound in resisting food-borne pathogenic bacteria and dairy cow mastitis pathogenic bacteria. The licoflavone compound has the advantages that the licoflavone compound can be used for treating food-borne bacterial diseases caused by food-borne bacteria such as escherichia coli, bacillus cereus, listeria monocytogenes and salmonella enteritidis; food-borne fungal diseases caused by food-borne fungi such as aspergillus flavus, penicillium expansum and monilinia coerulea; the licochalcone A shows certain inhibitory activity on dairy cow mastitis pathogenic bacteria caused by streptococcus agalactiae, streptococcus dysgalactiae, escherichia coli and staphylococcus aureus, and particularly has an obvious inhibitory effect on food-borne pathogenic bacteria and dairy cow mastitis pathogenic bacteria by three licochalcone A with different contents. The compound disclosed by the invention is simple in structure and relatively high in safety, and is expected to be developed into a novel antibacterial drug.

The application discloses a kind of fluorescence colorimetric double-mode detection streptococcus agalactiae without aerosol pollution method, comprising the following steps: (1) strain culture and DNA extraction;(2) the combination of UDG and LAMP;(3) UDG-LAMP-CRISPR fluorescence mode detection system;(4) colorimetric mode detection system: read image RGB value in G value, G value significantly increases, and it is positive result.This patent innovatively combines UDG, LAMP, CRISPR and G4, introduces connection probe to realize "fluorescence-colorimetric" single system double-mode detection.The two detection modes of the detection platform can be freely split or combined, and can meet the needs of different detection environments.By combining UDG system and LAMP technology, aerosol pollution possibly carried in amplification process is avoided.Connection probe is introduced, CRISPR fluorescence detection is combined with G4 colorimetric detection, a detection system with "fluorescence-colorimetric" two detection modes is established, which is used for quantitative identification and cross verification of streptococcus agalactiae.

The application discloses a bocachito Nat10 antibacterial peptide, a coding sequence and use and a preparation method thereof, and relates to a method based on multiomics, a biological big data based on multiomics data of bocachito, screening and identifying an antibacterial peptide precursor gene sequence, and obtaining an amino acid sequence of the bocachito Nat10 antibacterial peptide through translation design, as shown in SEQ ID NO: 3. Through activity simulation prediction and in-vitro experiment verification, the bocachito Nat10 antibacterial peptide shows inhibitory effects on the growth activities of Streptococcus agalactiae, Salmonella enteritidis, Staphylococcus aureus, Vibrio anguillarum and Escherichia coli, especially on Staphylococcus aureus, and shows the best antibacterial effect at a concentration of 2.5 micromoles per liter. The bocachito Nat10 antibacterial peptide can be used for preparing various bactericidal preparations, including bacteriostatic agents, medicines or additives, and has good practical value and social ecological benefits.

The invention discloses preparation and application of a nano antibody targeting streptococcus agalactiae SIP protein, and relates to the technical field of biology, the nano antibody efficiently and specifically bound with the SIP protein is screened out through nano antibody phage library construction and phage screening technologies, the nano antibody of the streptococcus agalactiae SIP protein comprises a VHH fragment, and the VHH fragment is a VHH fragment. The gene has an amino acid sequence as shown in SEQ ID NO: 1. The nanometer antibody can be combined with streptococcus agalactiae SIP protein in a high-specificity mode, the antibody can act on the SIP protein in a targeting mode, and the nanometer antibody targeting the streptococcus agalactiae SIP protein can be applied to diagnosis and treatment of fish diseases.

The invention discloses a method for evaluating streptococcus agalactiae resistance of genetically improved farmed tilapia. According to the invention, firstly, DNA methylation difference analysis is carried out aiming at the streptococcus agalactiae resistance traits of the genetically improved farmed tilapia, a DNA methylation molecular marker lcp2a308-485 associated with the traits is developed on the basis, and a pair of methylation marker detection primers associated with the streptococcus agalactiae resistance traits of the genetically improved farmed tilapia is provided. The methylation degree of the DNA methylation molecular marker lcp2a308-485 of a plasma cfDNA sample of Oreochromis niloticus has good correlation with the resistance of Streptococcus lactis, and the DNA methylation molecular marker can be used for noninvasive or minimally invasive detection of the resistance of Streptococcus lactis and can be used for breeding of sex Streptococcus lactis resistant Oreochromis niloticus. The breeding efficiency can be greatly improved, the practical problems of long breeding period, high input cost and the like in traditional disease resistance breeding can be solved, and the method has important significance on industrial development of genetically improved farmed tilapia mossambica.

The present application relates to the field of biotechnology, and particularly relates to a KASP molecular marker related to the resistance of tilapia to streptococcus agalactiae disease and an application thereof.Two SNP sites (SNP-1 and SNP-2) significantly associated with the resistance are screened from the intron region of EGFRX2 gene of tilapia, a typing method of the above sites is developed through KASP technology, and the correlation between the SNP-1 genotype and the resistance phenotype is verified.Further, an advantage haplotype individual with the resistance to streptococcus agalactiae disease is screened by combining the two SNP sites, and the survival rate of the individual in the challenge experiment is significantly improved.The detection kit provided by the present application can realize high-throughput and high-precision typing, is suitable for the identification of the resistance genotype of tilapia and the marker-assisted selection, provides an efficient genetic improvement tool for the disease-resistant breeding of tilapia, and is helpful to reduce the loss of breeding diseases and reduce the dependence on antibiotics.

The invention discloses a streptococcus agalactiae attenuated strain, a vaccine and application of the streptococcus agalactiae attenuated strain, and belongs to the technical field of veterinary biological products. The streptococcus agalactiae attenuated strain is obtained by knocking out a marR gene of a streptococcus agalactiae virulent strain HN016; wherein the nucleotide sequence of the marR gene is as shown in SEQ ID NO: 1. After the marR gene of the streptococcus agalactiae virulent strain HN016 is knocked out, the streptococcus agalactiae attenuated strain of which the virulence is remarkably reduced is obtained, and after the streptococcus agalactiae attenuated strain is prepared into the vaccine, the survival rate of aquatic animals infected with streptococcus agalactiae can be remarkably improved, so that the survival rate of the aquatic animals infected with streptococcus agalactiae is improved. The streptococcus agalactiae attenuated strain has a good application prospect in preparation of drugs for preventing and / or treating streptococcus agalactiae infection of aquatic animals.

The application discloses a recombinant strain and a preparation method thereof and application of the recombinant strain in preparation of a vaccine for Streptococcus agalactiae of tilapia, and the recombinant strain is successfully constructed by the following steps: designing an ORF4 primer, amplifying an ORF4 gene fragment from a DNA template of Streptococcus agalactiae, editing the ORF4 gene fragment into Escherichia coli by means of a CRISPR / Cas9 gene editing technology, and connecting a green fluorescent protein (GFP). The recombinant strain is subjected to immunoprotection research on the Streptococcus agalactiae of tilapia, and it is shown that the recombinant strain has a good protection effect, and can provide a solid theoretical basis and technical support for application and development of the vaccine for Streptococcus agalactiae of tilapia in the field of aquaculture.

The present application relates to the field of biotechnology, and more particularly to a SNP marker related to the level of anti-streptococcus agalactiae IgM antibody of tilapia and application thereof. The present application screens out QTLs, functional genes and key signal pathways significantly related to the level of anti-streptococcus agalactiae IgM antibody of tilapia by RNA-Seq and BSA-Seq technologies, and further identifies two SNP markers closely related to the level of anti-streptococcus agalactiae IgM antibody of tilapia, thereby providing important genetic targets and tools for molecular marker-assisted breeding of anti-streptococcus agalactiae of tilapia.

The invention belongs to the field of microorganisms, and discloses a bacterial strain having an antagonistic effect on pathogenic bacteria of cow mastitis and application of the bacterial strain, the bacterial strain SUD-8 having the antagonistic effect is paenibacillus polymyxa, and the bacterial strain SUD-8 has the antagonistic effect on the pathogenic bacteria of cow mastitis and application of the bacterial strain SUD-8 to the pathogenic bacteria of cow mastitis. The strain has an antagonistic effect on klebsiella pneumoniae, escherichia coli, staphylococcus aureus, streptococcus uberis and streptococcus dysgalactiae, and the growth speed in the cow dung back-mattress material is high.

The invention belongs to the research field of streptococcus agalactiae resistance of tilapia gill flora, and discloses a method for determining streptococcus agalactiae resistance of tilapia gill flora. According to the method, the Guifil No.1 growing quickly and the ZL resisting streptococcus agalactiae disease are subjected to reciprocal cross, and the streptococcus agalactiae resistance, catalase level and difference between a gill flora and a parent of a hybrid offspring are compared, so that the relationship between genetic differentiation and a gill flora structure is evaluated; the key function of tilapia gill flora in resisting streptococcus agalactiae is preliminarily revealed. Researches show that after the disease-resistant variety ZL is hybridized with the GIFT growing quickly, the filial generation of the disease-resistant variety ZL tends to inherit the flora of the ZL, and certain disease resistance is obtained.

The present application relates to the field of biotechnology, and more particularly to a detection method for resistance of tilapia to streptococcosis, a KASP primer set and application. The present application identifies a key SNP site of the ABCB4 gene significantly associated with resistance of tilapia to streptococcosis by the method of population genetics, and develops a genotyping method for the SNP site by KASP technology, thereby realizing efficient evaluation of the disease-resistant trait. Experimental data show that the survival time of AA genotype individuals in the challenge test is longer than that of GA / GG genotype individuals, the proportion of resistant fish is significantly improved, and the genotype frequency distribution is strongly correlated with the disease resistance of the population. The breeding strategy based on the SNP marker can improve the overall disease resistance of the breeding population and reduce the mortality rate, thereby providing an efficient genetic improvement tool for breeding of tilapia resistant to streptococcosis, and helping to reduce the loss of breeding diseases and reduce the dependence on antibiotics.

The present application relates to the field of microbial technology, in particular to bacillus subtilis BS-1 and its application in water buffalo silage feed, the strain BS-1 of the present application has good bacteriostatic activity on escherichia coli, salmonella and streptococcus uberis, after mixing and fermenting according to a specific proportion with orange peel and cassava residue, the bacteriostatic spectrum of the obtained silage feed is significantly enhanced, which can simultaneously inhibit escherichia coli, campylobacter jejuni, salmonella, streptococcus uberis, staphylococcus aureus and streptococcus agalactiae that cause diarrhea and mastitis. In the feed, after mixing 60%-75% of orange peel and 25%-40% of cassava residue, the crude protein content of the fermentation product is significantly improved, and the fiber content is reduced. Feeding test shows that the feed can significantly improve the milk yield and milk quality of lactating water buffalo, and effectively alleviate diarrhea. The present application provides a safe, efficient and nutritious silage feed with disease prevention function.

The invention belongs to the field of microorganisms, and relates to lactobacillus rhamnosus and application thereof. The lactobacillus rhamnosus KC3 is separated from Xinjiang healthy bactrian camel milk, and the lactobacillus rhamnosus KC3 has the activity of inhibiting various pathogenic bacteria such as escherichia coli, klebsiella pneumoniae, salmonella, proteus mirabilis, staphylococcus aureus, staphylococcus epidermidis, listeria monocytogenes and streptococcus agalactiae. The metabiotics of the strain can enhance the sensitivity of pathogenic bacteria such as escherichia coli and staphylococcus aureus to antibiotics such as beta-lactam antibiotics, and can synergistically enhance the antibacterial effect of the beta-lactam antibiotics to the pathogenic bacteria such as escherichia coli, staphylococcus aureus, CRE or MRSA. The lactobacillus rhamnosus KC3 metagen can also destroy cell walls of pathogenic bacteria such as escherichia coli, staphylococcus epidermidis, CRE or MRSA and the like, and the formation of bacterial biofilms is inhibited.

The invention discloses a lactobacillus plantarum bacteriostatic agent and application thereof, and relates to the technical field of microbial engineering. According to the lactobacillus plantarum LP2301 provided by the invention, fermentation liquor of the lactobacillus plantarum LP2301 can be used for effectively inhibiting aquatic pathogenic bacteria streptococcus agalactiae, limiting the growth of the streptococcus agalactiae, reducing the use of antibiotics, ensuring food safety and guaranteeing the health of animals and human beings by secreting metabolites such as bacteriostatic proteins and organic acids. Secondly, the invention provides an application of the lactobacillus plantarum bacteriostatic agent, and the lactobacillus plantarum LP2301 is compounded into the bacteriostatic agent; through multi-target cooperation of the cortex phellodendri extract and the rosmarinic acid, the antibacterial efficiency of single probiotics is remarkably optimized; active ingredients of cortex phellodendri directionally destroy a biological membrane barrier of streptococcus agalactiae and disintegrate an adhesion defense system of pathogenic bacteria; rosmarinic acid blocks a bacterial energy metabolism pathway synchronously, so that pathogens lose proliferative power; and exclusive bacteriocin secreted by the LP2301 accurately breaks down a cell membrane structure, so that fatal killing is realized.

The application belongs to the technical field of Chinese herbal medicines, and particularly relates to a Chinese herbal medicine composition for resisting Streptococcus agalactiae, a preparation method and application thereof. Raw materials for preparing the Chinese herbal medicine composition include cortex mali and cumin. The Chinese herbal medicine composition is easy to obtain and simple to prepare, has no chemical residues, is not prone to drug resistance, has significant bacteriostatic activity on Streptococcus agalactiae, and can be applied to the prevention and treatment of Streptococcus agalactiae disease of fish such as tilapia.

The present invention discloses a method for preparing a eukaryotic expression vector of Nile tilapia CD36 protein and its application. The method comprises extracting RNA from Nile tilapia intestinal tissue and synthesizing cDNA; performing PCR amplification on the coding sequence fragment of the Nile tilapia CD36 gene to obtain the Nile tilapia CD36 protein gene; and then constructing a eukaryotic expression vector pEGFP-N1-CD36 of the Nile tilapia CD36 protein. The eukaryotic expression vector of the nucleotide sequence of the Nile tilapia CD36 protein prepared by the present invention can be used to prepare a product that improves the anti-streptococcal immunity of tilapia. The preparation of the product is simple, easy to operate, and low in cost. The present invention enhances the anti-streptococcal ability of tilapia by overexpressing the Nile tilapia CD36 protein in tilapia, thereby increasing the survival rate of tilapia infected with Streptococcus agalactiae by 60%. In addition, overexpressing the Nile tilapia CD36 protein in tilapia can also reduce the Streptococcus agalactiae load in tilapia. Therefore, it can be seen that the technical solution of the present invention can effectively induce cellular immunity in tilapia.

The invention discloses a Basa fish Mob1b antibacterial peptide as well as a coding sequence, application and a preparation method thereof, an antibacterial peptide precursor gene sequence is screened and identified from a Basa fish multi-omics data set based on a multi-omics method and biological big data, and an amino acid sequence of the Basa fish Mob1b antibacterial peptide as shown in SEQ ID NO: 3 is obtained through translation design; activity simulation prediction and in-vitro experiments prove that the Basa fish Mob1b antibacterial peptide has an inhibition effect on growth activity of streptococcus agalactiae, salmonella enteritidis, staphylococcus aureus, vibrio anguillarum and escherichia coli; the compound can be used for preparing various antibacterial agents, especially gram-positive bacteria streptococcus agalactiae, gram-negative escherichia coli staphylococcus aureus and vibrio anguillarum, can show an antibacterial effect when the concentration is 2.5 mu mol / L, can achieve the best antibacterial effect when the concentration is 5 mu mol / L, can be used for preparing various antibacterial agents and the like, and has good practical value and social and ecological benefits.

The invention provides a tilapia mossambica antibacterial peptide OnLEAP-2 and application thereof, an antibacterial peptide named OnLEAP-2 is cloned from tilapia mossambica, and a large number of antibacterial peptides are obtained through prokaryotic expression. The antibacterial peptide has a very good function of resisting streptococcus agalactiae, so that the survival rate of tilapia mossambica is remarkably increased, and pathogens are efficiently removed. The composition is suitable for bacterial disease control of economic fishes such as tilapia.

The present invention relates to molecular biology and aquaculture breeding, specifically to a method for obtaining a PRMT2 gene mutant by knocking out the gene based on CRISPR / Cas9 technology, and establishing an antibacterial strain of tilapia with a PRMT2 knockout. By knocking out this gene, a tilapia strain resistant to Streptococcus agalactiae can be obtained. Infection experiments revealed that tilapia with a PRMT2 knockout gene exhibited enhanced antibacterial activity compared to wild-type tilapia. This invention provides an important model for disease-resistant tilapia breeding and offers gene targets and new research directions for creating more disease-resistant fish strains and varieties.

The present invention relates to compositions and methods for detecting group B streptococcus (GBS, Streptococcus agalactiae) and identifying the most common genes responsible for clindamycin resistant GBS, such as ermB, ermTR, ermT, lsaC and lsaE, by multiplex real-time PCR assays.