34 results about "Kanamycin" patented technology

The invention designs a preparation method of a magnetic molecular imprinting-aptamer sandwich fluorescence sensor for detecting kanamycin. And the magnetic molecular imprinting composite material Fe3O4 (at) UiO-66 (at) MIP with a specific adsorption target object KANA is prepared. When a detection target object KANA exists, the Fe3O4-coated UiO-66-coated MIP can rapidly and specifically capture the KANA in a short time. Then, a DNA single-stranded aptamer marked with FAM is added, after the aptamer and KANA captured on the surface of the Fe3O4 at-UiO-66 at-MIP are subjected to specific recognition and magnetic separation again, an aptamer probe can enter sediment along with the magnetic composite material Fe3O4 at-UiO-66 at-MIP, the fluorescence intensity of supernate is reduced, and quantitative analysis is conducted according to the fluorescence difference value delta F. When the KANA does not exist, the aptamer cannot enter the precipitate, so that the fluorescence signal intensity is not changed. Double recognition is formed through specific binding of an MIP imprinting cavity and the aptamer, matrix interference is reduced by means of fluorescence characteristics and magnetic separation capacity, the method has the advantages of being high in adsorption capacity, specific in recognition, high in sensitivity, wide in detection range, good in selectivity and the like, and rapid and accurate detection of KANA in a complex sample can be achieved.

This invention provides a composite aerogel based on Eucommia ulmoides gum and MXene nanosheets, its preparation method, and its application. The aerogel is prepared by reacting a toluene solution of Eucommia ulmoides gum with Ti3C2T... x MXene aqueous solution was mixed and a water-in-oil microemulsion was formed using a combination of ultrasound-assisted shaking. This allowed MXene nanosheets to self-assemble at the microemulsion droplet interface. Following vertical freezing and freeze-drying processes, a three-dimensional network structure of Eucommia ulmoides gum-Ti3C2T was successfully constructed. x MXene composite aerogel. The preparation method of this invention is mild and requires no chemical cross-linking agents. The resulting composite aerogel exhibits excellent adsorption performance for enrofloxacin, malachite green, Congo red, rhodamine, and kanamycin in water, with adsorption equilibrium times all within 10 minutes, enabling rapid removal of organic pollutants from water. This invention provides a new approach for the high-value utilization of Eucommia ulmoides gum and has promising application prospects in the field of water environment remediation.

The present application relates to the technical field of biology, and discloses a construction method of a Pseudomonas putida suicide vector and application thereof.The construction method of the Pseudomonas putida suicide vector provided by the present application takes a pK18mobsacB vector as a template to obtain a vector skeleton by amplification, and then takes Pseudomonas putida KT2440 bacterial liquid as a template to obtain a strong promoter Prib, upper and lower homologous arms of a gene x to be knocked out, and connects the upper and lower homologous arms to the vector skeleton to obtain the Pseudomonas putida suicide vector.The strong promoter Prib can increase the expression amount of sacB sucrose in the Pseudomonas putida, and enhance the sucrose lethal effect.The Pseudomonas putida suicide vector obtained can be introduced into the Pseudomonas putida, and then the strain with the target gene to be knocked out deleted can be obtained efficiently and accurately through kanamycin positive screening and sucrose negative screening.

The application discloses a pesticide composition containing zhongshengmycin and kanamycin and application thereof, and belongs to the technical field of pesticides. Effective components of the pesticide composition are zhongshengmycin and kanamycin. The mass ratio of the kanamycin to the zhongshengmycin is 1:1-9. The two effective components of the application have different action sites for killing pathogenic bacteria, and can effectively alleviate the generation of drug resistance of the pathogenic bacteria. After the zhongshengmycin and the kanamycin are compounded, synergistic effect is obvious, the control effect of the pesticide on bacterial diseases, such as citrus canker, is improved, the pesticide dosage can be reduced, and agricultural residues are reduced. Meanwhile, the prepared soluble granules do not use any organic solvent, are safe to crops, and have no residues and pollution to the environment.

The application provides a nucleic acid sequence and a method for detecting biomolecules based on a self-driven hybrid chain reaction (SHCR), which comprises a priming chain AI, a blocking chain B, a hairpin probe H1, a hairpin probe H2, a hairpin probe H3 and a hairpin probe H4, the priming chain AI comprises an aptamer sequence of a to-be-detected biomolecule and a starting sequence I, the sequence of the starting sequence I is a*‑b*, wherein a* and b* are gene fragments; the 5' end of the hairpin probe H1 is connected with b*, and the 3' end of the hairpin probe H3 is connected with a*. The application further provides a kit for detecting biomolecules based on the SHCR and a method for detecting biomolecules, in particular, a method for detecting a kanamycin residual amount in food. Through ingenious design, when the to-be-detected biomolecule exists, the sequence combination of the above biomolecule can initiate the self-driven hybrid chain reaction, the priming chain can be autonomously supplemented, the self-driven reaction process is reversely activated, thereby a more significant FRET signal is generated, and the detection sensitivity is improved.

The application belongs to the technical field of microorganism detection, and particularly relates to a bifidobacterium viable count detection culture medium, a detection method and application. The application provides a culture medium for detecting bifidobacterium, wherein the culture medium comprises MRS culture medium and an antibiotic solution; the antibiotic solution comprises streptomycin, kanamycin and sodium propionate. The culture medium can ensure normal growth of bifidobacterium, has strong inhibition on lactobacillus, can effectively realize accurate detection of bifidobacterium, and avoids interference of lactobacillus.

The invention provides Kineococcus G2 and application of the Kineococcus G2 in preparation of a pigment with antioxidant activity, the Kineococcus new strain G2 is CCTCC No. M20242602, the strain is spherical, the size is 1.0 * 1.5 mu m, the optimal growth temperature is 30-37 DEG C, the pH value is 7.0-9.0, and the salt concentration is 1.0%-2.0%. The strain G2 is not sensitive to bacitracin, ciprofloxacin and norfloxacin, and is sensitive to novobiocin, polymyxin, gentamicin, piperacillin, ofloxacin, erythromycin, streptomycin, kanamycin, rifampicin, ampicillin, vancomycin, carbenicillin, chloramphenicol, tetracycline, penicillin, cefoperazone, oxacillin, amoxicillin and neomycin. Pigment generated by fermentation of the G2 strain has good antioxidant activity, and when the concentration is 10 micrograms / mL, the scavenging activity on DPPH is 25.00%, the scavenging activity on hydroxyl radicals is 80.58%, and the iron ion reducing capacity is 1.57, which are all higher than those of contrast beta-carotenoid. The application of the new Kineococcus strain G2 can lay a foundation for the research of antioxidant drugs such as medical treatment and health care product development.

The application discloses a fermentation method for producing thiamine pyrophosphokinase and belongs to the technical field of bioengineering. The BL21 recombinant engineering bacteria containing pET28a-TPK, pET28a-ProS2-TPK or pET28a-SUMO-TPK are constructed, the seed liquid is prepared, the isopropyl-beta-D-thiogalactoside is used for inducing expression, the bacteria are collected, the cells are broken and the supernatant is collected to obtain the TPK crude enzyme liquid. In the fermentation, the LB / TB culture medium containing 50 μg / mL kanamycin or 100 μg / mL ampicillin is used. The SUMO label is introduced to guide the correct folding of the TPK, so that the soluble expression ratio of the TPK is more than 85%, the ratio is improved by 2 times compared with the common system, the inclusion body ratio is greatly reduced, the process is stable and has good repeatability, and an effective scheme is provided for the industrialized large-scale preparation of the TPK.

This invention relates to the field of genetic engineering technology, specifically disclosing a polyclonal antibody against citrus HIPP7 protein, its preparation method, and its applications. The method includes selecting amino acid 1-246 of the HIPP7 protein sequence for prokaryotic expression, synthesizing the sequence and ligating it into the vector pET41a to construct pET41a-HIPP7, transforming it into *E. coli*, culturing it in LB liquid medium containing kanamycin, inducing expression with IPTG, isolating and purifying the protein, and preparing a polyclonal antibody against citrus HIPP7 protein by immunizing rabbits with the HIPP7 protein. The polyclonal antibody against citrus HIPP7 protein obtained by this invention can specifically detect citrus HIPP7 protein and can be used to detect the accumulation of HIPP7 protein in different citrus tissues and under different treatment conditions, as well as to detect the accumulation of HIPP7 protein in transgenic plants.

The invention discloses a stable genetic transformation method of floating moss. The genetic transformation method comprises the following steps: (1) crushing thallus tissues of the floating moss, (2) pre-culturing explants, (3) infecting and co-culturing, (4) screening and culturing for the first time, (5) screening and culturing for the second time, (6) enlarging and culturing, and (7) verifying transformation. According to the genetic transformation method, a thallus of floating moss is taken as a starting explant, an agrobacterium-mediated hygromycin and kanamycin screening transformation system of the floating moss is established for the first time, the blank of a floating moss genetic transformation system is filled, and experimental results show that after multi-generation culture, a transformed plant can still stably express a target gene. The method has the advantages of high transformation efficiency and simplicity in operation, and can be used for subsequent genetic transformation research of unknown floating moss genes. The method has a wide application prospect.

The invention discloses an SlFMO1 gene and application thereof in regulation and control of growth and development of tomato plants, and belongs to the technical field of gene engineering. According to the method, a CRISPR / Cas9 gene editing technology is utilized, firstly, a CRISPR / Cas9-gRNA vector is constructed to accurately edit an SlFMO1 gene in tomatoes, GV3101 agrobacterium tumefaciens is utilized to conduct mediated transformation on the tomatoes, and kanamycin serves as a resistance marker to conduct screening to obtain SlFMO1-deleted mutant tomatoes. Phenotype observation and analysis show that after the SlFMO1 gene is knocked out, the plant height and the plant width of a tomato plant are obviously increased, the apical development is enhanced, the stem diameter of the plant is increased, and the inflorescence spacing is increased, which indicates that the SlFMO1 gene negatively regulates the growth and development of the tomato, and meanwhile, the expression of related genes synthesized by auxin, gibberellin and brassinolide is obviously enhanced. The discovery has important theoretical significance and practical application value for follow-up cultivation of ideal tomato varieties.

The invention relates to a construction method of an Agrobacterium rhizogenes mediated acacia melanoxylon genetic transformation system, which comprises the following steps: by taking an acacia melanoxylon SR17 sterile single plant as an explant, selecting an Agrobacterium rhizogenes strain Ar1193, infecting for 45 minutes in a heavy suspension of which the bacterial liquid concentration OD600 is equal to 0.9 and the acetosyringone concentration is 100 [mu] mol.L <-1 >, co-culturing for 3 days, and then transferring into a bacteriostatic culture medium to induce hairy roots; and taking the transgenic hairy roots obtained by induction as explants, and inoculating the explants into a WPM culture medium containing 0.05 mg.L <-1 > TDZ and 200 mg.L <-1 > casein hydrolysate to induce regeneration of adventitious buds so as to obtain complete transgenic plants. The screening concentrations of the four antibiotics, namely kanamycin, hygromycin, glyphosate and glufosinate-ammonium, are determined; a stable and efficient acacia melanoxylon genetic transformation system is established, the hairy root induction rate reaches 63.17%, the transgenic positive rate reaches 15.42%, and the adventitious bud regeneration rate reaches 52%.

The invention discloses an SlFMO1 gene and application of the SlFMO1 gene in regulation and control of resistance of tomato fruits to gray mold, and belongs to the technical field of gene engineering. A CRISPR / Cas9 gene editing technology is utilized, firstly, a CRISPR / Cas9-gRNA vector is constructed to accurately edit the SlFMO1 gene in tomatoes, GV3101 agrobacterium tumefaciens is utilized to conduct mediated transformation on the tomatoes, kanamycin serves as a resistance marker to conduct screening to obtain SlFMO1-deleted mutant tomatoes, it is found that when the SlFMO1 gene in the tomatoes is deleted, the resistance of tomato fruits to gray mold is remarkably reduced, and when the SlFMO1 gene in the tomatoes is deleted, the resistance of the tomato fruits to gray mold is remarkably reduced. The result shows that the SlFMO1 gene positively regulates and controls the resistance of the tomato to the gray mold. The discovery provides a new target for subsequent improvement of tomato varieties and creation of materials for resisting gray mold of fruits, and has important application prospects in molecular breeding for improving disease resistance of tomato fruits.

The invention discloses a preparation method and application of a molecularly imprinted polymer and aptamer double-recognition gold nanoparticle-laser induced graphene composite material modified electrode, and belongs to the technical field of flexible electrochemical sensors and kanamycin detection. According to the invention, a gold nanoparticle-laser-induced graphene composite material modified electrode is used as a base material, a kanamycin aptamer is fixed through a gold-sulfur bond by using gold nanoparticles on the surface of the base material, and a molecularly imprinted polymer layer is further modified; therefore, an electrochemical sensing electrode with a molecularly imprinted polymer and aptamer dual recognition interface is constructed, and the electrochemical sensing electrode is used as a high-performance sensitive element of a sensor and shows good analysis performance in actual fish meat sample kanamycin detection. The prepared modified electrode can be used for sensitively detecting KANA in a concentration range of 10.0 pmol / L-1. 0mmol / L, the detection limit is as low as 3.3 pmol / L, and the modified electrode is good in selectivity and stability.

The invention provides an SP-1 polypeptide and application of a coding gene of the SP-1 polypeptide in inhibition of tight reaction and antibiosis, and belongs to the technical field of polypeptides. The amino acid sequence of the spider-derived SP-1 polypeptide is as shown in SEQ ID NO: 1. According to the present invention, the SP-1 polypeptide can specifically inhibit Escherichia coli and pseudomonas aeruginosa tight reaction key small molecule (p) ppGpp synthase activity, strong antibacterial activity is represented, and the MIC of the SP-1 polypeptide on Escherichia coli and pseudomonas aeruginosa is 2.4 [mu] M and 1.5 [mu] M respectively, and is significantly lower than the MIC (14.5 [mu] M and 12.3 [mu] M) of kanamycin of a positive control group under the same experiment condition; in addition, the SP-I peptide shows efficient bactericidal activity, the minimum bactericidal concentration of the SP-I peptide to escherichia coli and pseudomonas aeruginosa is 2.0 mu M, and the SP-I peptide can effectively inhibit generation of escherichia coli and pseudomonas aeruginosa biological membranes. Therefore, the SP-1 polypeptide can be used as an active ingredient to be applied to preparation of antibacterial drugs for inhibiting multidrug resistance bacteria.

The invention provides a preparation method of spirolactone, and relates to the technical field of organic synthesis. The preparation method of spirolactone provided by the invention comprises the following steps: taking 4-androstene-3, 17-diketone as a raw material, carrying out nucleophilic addition reaction on the 4-androstene-3, 17-diketone and an organic zinc reagent 3-tert-butoxy-3-oxypropyl zinc bromide, then carrying out elimination-lactonization under the catalysis of trifluoroacetic acid, and completing lactonization while removing tert-butyl; then sequentially carrying out etherification reaction and oxidative dehydrogenation reaction to obtain canrenone, and finally carrying out addition reaction on canrenone and thioacetic acid to obtain spirolactone. The preparation method provided by the invention provides a novel construction method of 21-carboxylic acid-gamma-lactone, the method is good in specificity, the total mass yield of spirolactone is greater than 92%, and the total mass yield is high; moreover, the HPLC purity of the spirolactone prepared by the preparation method provided by the invention is greater than 99.7%, which is far higher than the purity of the spirolactone prepared by the existing process.

This invention discloses a method for introducing exogenous genes into Gynostemma pentaphyllum, comprising: S1: Selecting Gynostemma pentaphyllum seeds with seed coats within 3 months of harvest, disinfecting, and culturing to obtain aseptic seedlings from seedlings, or selecting stem segments with axillary buds after leaf removal, disinfecting, and culturing using a subculture proliferation medium containing cephalosporin to obtain aseptic rooted seedlings; S2: Selecting the aseptic seedlings or aseptic cuttings obtained in S1, culturing in a rooting medium containing cephalosporin to obtain aseptic rooted seedlings; S3: Transforming plasmid Pcambia1301-PMI into Agrobacterium and culturing in a medium containing kanamycin and rifampin to obtain an Agrobacterium resuspension; S4: Infecting the aseptic rooted seedlings obtained in S2 with the Agrobacterium resuspension, and performing co-culture, antibacterial culture, and screening culture to obtain transgenic adventitious shoots. This invention can successfully introduce exogenous genes into Gynostemma pentaphyllum, obtaining Gynostemma pentaphyllum positive plants.

The chitinase 3-like 1 (CHI3L1) inhibitor, specifically kasugamycin, provided by the present invention, suppresses the expression or activation of chitinase 3-like 1 (CHI3L1), thereby effectively preventing or treating infections with acid-fast bacteria, particularly non-tuberculous mycobacteria and various diseases caused by infection with acid-fast bacteria, particularly nontuberculous mycobacteria. In addition, by measuring the expression level of chitinase 3-like 1 (CHI3L1) protein, when the expression level is higher than that of a control group, it is possible to effectively predict infection with acid-fast bacteria, particularly non-tuberculous mycobacteria, the onset of diseases caused by infection with acid-fast bacteria, particularly non-tuberculous mycobacteria, or the prognosis of diseases related to infection with acid fast bacteria, particularly nontuberculous mycobacteria.

The invention discloses construction and application of a vibrio parahaemolyticus capsular polysaccharide synthesis gene cluster and lipopolysaccharide synthesis HldE mutant strain, and belongs to the technical field of molecular biology and genetic engineering.According to the construction method, an overlapping extension PCR technology is adopted for constructing a kanamycin resistance gene knockout fusion fragment, the fusion fragment is cloned into a suicide plasmid pDS132, and the suicide plasmid pDS132 is used for preparing the HldE mutant strain of the vibrio parahaemolyticus capsular polysaccharide synthesis gene cluster and lipopolysaccharide synthesis HldE mutant strain. A recombinant suicide plasmid is introduced into vibrio parahaemolyticus through conjugational transfer, and sucrose-induced double-exchange homologous recombination and kanamycin resistance screening are utilized to efficiently obtain a capsular polysaccharide synthetic gene cluster and an HldE gene knockout mutant strain. The invention further discloses an application of the mutant strain in evaluating the exposure of the outer membrane protein, and discloses the influence of a capsule and a lipopolysaccharide layer on the accessibility of an outer membrane protein antibody. The method is easy and convenient to operate and high in screening efficiency, and an effective tool is provided for vibrio outer membrane protein function research, vaccine target screening and pathogenic mechanism analysis.

The invention belongs to the technical field of medicines, and provides application of dicentrine in preparation of a medicine for treating kanamycin drug-resistant bacterium infection. According to the invention, dicentrine and kanamycin are combined for use to inhibit drug-resistant bacteria expressing EanT-1 nucleotide transferase, such as EanT-1-producing Exiguobacterium or Escherichia coli carrying an eanT-1 gene. The dicentrine is competitively combined with an EanT-1 enzyme active center to block the modification inactivation effect of the dicentrine on kanamycin. The composition can significantly reduce the minimum inhibitory concentration (MIC) of drug-resistant bacteria to kanamycin, and shows a synergistic antibacterial effect in vitro and in a mouse septicemia model.

The invention discloses a multi-immunochromatography test strip with unified detection limit for detecting four aminoglycoside drugs and application of the multi-immunochromatography test strip. The test strip comprises a water absorption plate, a detection pad, a colloidal gold pad, a sample pad and a PVC (polyvinyl chloride) bottom plate, wherein a gold-labeled antibody is fixed on the surface of the colloidal gold pad, and when a sample flows through the colloidal gold pad, the gold-labeled antibody is dissolved and serves as a tracer molecule to migrate along with a liquid phase; four detection areas T1, T2, T3 and T4 and a quality control line area C are arranged on the detection pad, a kanamycin antigen, a gentamicin antigen, a neomycin antigen and a spectinomycin antigen are sprayed on the four detection areas respectively, and a goat anti-mouse antibody is sprayed on the quality control line area C. According to the present invention, the expensive reagent and the base material are not required, the production cost is low, the operation is simple, the professional training is not required, the detection efficiency is high, the detection cost is low, the multiple immunochromatography test strip is used for simultaneously detecting kanamycin, gentamicin, neomycin and spectinomycin, and the detection limits can achieve 5 ng / mL.

The invention provides bacillus C367 as well as a method and application thereof. The bacillus C367 is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCC No.36841; the bacillus C367 is separated from the Inner Mongolia cheese; the bacillus C367 can be used for preparing medicines for treating or preventing periodontal diseases; the invention provides a novel oral cavity probiotic bacillus C367, the bacillus C367 has an inhibition effect on periodontal disease bacteria, and the bacillus C367 is sensitive to antibiotics such as minocycline, amikacin, tetracycline, erythromycin, cefoperazone, streptomycin, kanamycin, gentamicin, vancomycin and ceftriaxone, and has good survival ability in an oral cavity.

The application belongs to the technical field of genetically engineered bacteria, and specifically discloses a high-yield thiostrepton engineered bacterium based on double reporter genes, a construction method and application thereof. The construction method comprises the following steps: introducing a recombinant expression vector containing a promoter sequence of tsrI-tsrH and a reporter gene XylE into a host bacterium to obtain a donor bacterium; co-culturing the donor bacterium with Streptomyces laurentii to obtain a conjugant; culturing the conjugant in a culture medium containing kanamycin for screening, and then verifying XylE enzyme activity coloration, and finally screening a positive recombinant strain with yellow color. Through a double reporter gene combined screening strategy, the hit rate of screening of high-yield strains is increased from 28.0% of traditional single resistance screening to 92.0%, the fermentation titer of the screened recombinant strain reaches 333.43 U / mL, and the average yield is 3.3 times that of the single resistance screening group. The recombinant strain also has excellent genetic stability and is suitable for industrial production.

Aiming at the defects of incomplete protection of kanamycin A, more acylation side reactions, poor suitability with a microchannel reactor and the like in the existing silanization protection process, the invention provides the high-selectivity synthesis method of amikacin sulfate. According to the method, breakthrough is achieved through an improved route of silanization full protection, directional deprotection and microchannel acylation, and full protection of seven hydroxyl groups and four amino groups of kanamycin A is achieved by combining hexamethyldisilazane with a high-boiling-point solvent; due to spatial position and activity differences of four amino groups, a solvent containing a small amount of water is used for directionally removing a trimethylsilyl protecting group of a 1-position amino group; the particle size of the active ester is controlled to be smaller than or equal to 100 microns through high-speed stirring, and high-selectivity acylation is completed in the micro-channel reactor. According to the method, the ratio of the 1-position acylation product to the 3-position acylation product is increased to 20: 1 or above, the synthesis yield reaches 75% or above, and the method is suitable for industrial continuous production.

The invention discloses a bacterium visual detection and in-situ quantitative sterilization method and application, and relates to the field of bacterium detection and sterilization. According to the method, liquid crystal double-emulsion (LCDE) is taken as a carrier, hCG, alpha-amylase and kanamycin are loaded, and bacterium visual detection and in-situ quantitative sterilization are realized by combining a host-guest competition effect and a pregnancy test strip (PTS). The pyrene-modified single strand and the LPS aptamer are hybridized to form double strands, when a target (LPS or bacteria) exists, the aptamer is specifically bound with the double strands to release the pyrene-modified single strand, the pyrene-modified single strand competes to occupy a beta-CD cavity and release CTAB, and the stability of an LCDE interface is destroyed to release an internal drug carrier; exo I shears single-stranded DNA, alpha-amylase hydrolyzes beta-CD, and the Exo I and the alpha-amylase synergistically amplify signals. The technology is excellent in detection performance, the LPS detection limit reaches 0.8 ng / mL, and the escherichia coli detection limit is 1.2 CFU / mL; the kanamycin is released according to needs, the sterilization rate exceeds 80%, the problems of environmental pollution and drug resistance caused by excessive drugs can be avoided, operation is easy and convenient, stability is good, and the method has great application value in multiple fields.

The invention relates to the technical field of biological detection, and particularly discloses a kanamycin colorimetric sensor based on magnetic beads and G-quadruplex aptamer / hemin, and application of the sensor in kanamycin detection in food. The sensor comprises an aptamer which can be specifically combined with kanamycin and is as shown in SEQ ID: 1 and a cDNA sequence which is complementary to the kanamycin aptamer and is as shown in SEQ ID: 2, cDNA fixed on a magnetic bead is used as a capture probe, a G-quadruplex aptamer is used as a recognition probe, chlorhematin / G-quadruplex aptamer DNA enzyme is used as a signal probe, a nano magnetic bead separation technology is combined, and the detection sensitivity is high. The qualitative and quantitative detection of kanamycin is realized. The kanamycin colorimetric sensor provided by the invention is used for detecting kanamycin in food, the operation is simple, no professional instrument is needed, the detection cost is low, and the detection efficiency is high.

The invention relates to the technical field of prevention and control of animal infectious diseases, in particular to a construction method of a pdhB gene mutant strain of a mycoplasma bovis PG45 strain, which comprises the following steps: by taking M. bovis PG45 as parent bacteria, collecting thalli in a logarithmic later stage, washing the thalli with a sucrose-Tris / Cl buffer solution, resuspending the thalli in 0.1 M CaCl, and carrying out ice bath for 30 minutes; the method comprises the following steps: mixing competent cells with 20 [mu] g of pMT / mNeonGreen-RR, 10 [mu] g of yeast tRNA and 2 mL of 70% PEG 8000, incubating for 2 min, and washing with a sucrose-Tris / Cl buffer solution; culturing for 3 hours at 37 DEG C by utilizing 0.6 mL of nonreactive PPLO broth; after the incubation is finished, coating on a solid culture medium containing 100 mu g / mL kanamycin, culturing for 3-7 days at 37 DEG C, observing and screening out a green monoclonal colony by using a fluorescence microscope, culturing, preserving at-80 DEG C, and establishing a mycoplasma bovis PG45 random mutant library; a pdhB gene mutant strain, namely a Mycoplasma bovis PG45 delta pdhB strain, is obtained by identifying and screening through a specific primer PCR (Polymerase Chain Reaction). Compared with a wild type, the growth speed of the Mycoplasma bovis PG45 [delta] pdhB strain is obviously slowed down, and the adhesive force of the Mycoplasma bovis PG45 [delta] pdhB strain to EBL cells is obviously weakened.

The invention relates to the technical field of agricultural biology, and provides an efficient and stable canna edulis germplasm resource in-vitro preservation method which comprises the following steps: step 1, selecting healthy and pollution-free sterile canna edulis test-tube plantlets; 2, NAA, BA, kanamycin, hygromycin B, sucrose and agar are added to a B5 culture medium formula, and a culture medium is obtained; 3, the test-tube plantlets are inoculated into a culture medium, the culture medium is placed in an artificial climate box to be cultured, and subculture is conducted once every 6-8 months (the generations are controlled within 6 generations); 4, in the culture process, the growth condition of the test-tube plantlet is recorded regularly, and meanwhile, a conventional culture medium without a growth inhibitor is set as a control group. By optimizing a culture medium formula and controlling culture conditions, excessive growth of test-tube plantlets is effectively inhibited, formation of short and strong seedlings is promoted, and functions of root systems and leaves are enhanced, so that long-term, stable and efficient germplasm resource preservation is realized, the transplanting survival rate is remarkably increased, and the method has important application value.

Provided are a tetragenococcus halophilus with an inhibitory effect on bacillus cereus and a use thereof. The preservation number of the tetragenococcus halophilus is GDMCC 64945. The tetragenococcus halophilus is isolated from fermented bean curd, and colonies of the tetragenococcus halophilus are milky white, small and round on a solid medium; The tetragenococcus halophilus is Gram-positive, and when observed under a microscope, the morphology thereof is mostly diplococci or tetrads, with no chain-like formations. The strain is sensitive to eight antibiotics such as ampicillin, gentamicin and kanamycin, and has no drug resistance gene and virulence gene. A bacterial suspension of the strain has a good inhibitory effect on a bacillus cereus strain isolated from the fermented bean curd, and when the strain is applied to a fermented bean curd fermentation system, the growth of bacillus cereus in the system can be effectively inhibited, and the content of enterotoxin in the system is reduced.

This application proposes a kanamycin U-shaped fiber optic sensor, its fabrication method, and a fiber optic sensing system, belonging to the field of sensor detection technology. The sensor includes: a fiber core, a cladding, a silver film, a polydopamine layer, silver nanoparticles, a kanamycin aptamer, and mercaptohexanol. The silver film serves as a metal-sensitive layer, used to achieve wave vector matching between free electrons on the surface of the silver film and evanescent waves to excite plasmon resonance on the surface of the silver film. The polydopamine layer is used to immobilize the silver nanoparticles. The silver nanoparticles are used to excite the LSPR effect and to modify the surface of the kanamycin aptamer. Mercaptohexanol is used to fill non-specific binding sites. The kanamycin aptamer binds to kanamycin to change the refractive index of the fiber surface, thereby altering the resonance conditions between the evanescent wave and the surface plasmon wave, causing a redshift of the resonance wavelength. The sensor of this application shortens the response time of the kanamycin U-shaped fiber optic sensor, is simple to fabricate, and is small in size and lightweight.