35 results about "Avirulent strain" patented technology

A provided multiple fluorescence PCR detection kit for clostridium difficile toxin genes mainly comprises specific primers, probes and a PCR reaction reagent, and the specific primers and the probes respectively consist of specific primers and probes of clostridium difficile toxin A (tcdA), toxin B (tcdB), binary toxin A (cdtA) and binary toxinB (cdtB). The beneficial effects of the invention comprise: the fast, sensitive and specific multiple fluorescence PCR detection kit and a detection method are provided for the clostridium difficile toxin genes, and a foundation is provided for distinguishing between toxigenic strains and avirulent strains of clostridium difficile, and early diagnosis on infection of clostridium difficile.

Recombinant immunogenic compositions and methods for protecting against lethal infections from Bacillus anthracis having a variant of recombinant Bacillus anthracis protective antigen (rPA) and a variant of recombinant Bacillus anthracis lethal factor (rLF). These proteins may be expressed separately or as a fusion protein. The recombinant proteins are produced in an avirulent strain of Bacillus anthracis that overproduces the desired antigens. The compositions and methods induce the animal host to produce antibodies against a virulent strain of Bacillus anthracis.

The invention discloses an Aspergillus flavus avirulent strain and an application of the Aspergillus flavus avirulent strain in controlling pollution of Aspergillus flavus. In the avirulent strain, the Aspergillus flavus does not express pathogenesis related genes aflash1. The strain is non-toxic, does not produce sclerotium, produces a large quantity of spores in a culture medium and a small quantity of spores on an organism and has low pathogenicity. On the basis of the characteristics of the strain, the invention further discloses a method for controlling pollution of the Aspergillus flavus by use of the strain. More specifically, the method comprises steps as follows: by use of the characteristics that the Aspergillus flavus strain is non-toxic, does not produce sclerotium, produces a large quantity of spores in a culture medium and a small quantity of spores on an organism and has low pathogenicity, limited ecological niches are scrambled in main peanut producing areas and other susceptible areas of Aspergillus flavus through the strain and wild toxic-producing Aspergillus flavus strains, the density of the wild toxic-producing Aspergillus flavus strains is effectively reduced, and Aspergillus flavus infection to crops, Aspergillus flavus toxin pollution and aspergillosis infection caused by Aspergillus flavus toxin pollution are effectively controlled and reduced.

The invention discloses a detecting method of avirulent strains of fusarium, which is characterized in including following steps: (a) detecting isozyme of fusarium; (2) detecting beta-glucosaccharase of fusarium; (c) sequence detecting ITS of fusarium; (d) detecting liquid culture of fusarium, the detecting method can discriminate avirulent strains of fusarium effectively to use thereof as immuno inoculation dose for curepreventing fusarium wilt.

The invention discloses an LAMP assay kit for identifying virulent and avirulent strains of mycoplasma gallisepticum. A primer group A provided by the LAMP assay kit consists of a primer group a and a primer group b; the primer group a consists of a primer 1 and a primer 2; the primer group b consists of a primer 3 and a primer 4; and the nucleotide sequences of the primer 1, the primer 2, the primer 3 and the primer 4 are sequence 1, sequence 2, sequence 3 and sequence 4 sequentially in a sequence table. An experiment for the LAMP assay kit proves that the primers and the method only need anordinary water bath rather other an expensive PCR (Polymerase Chain Reaction) instrument but have higher sensitivity than PCR assay, moreover, a result does not need to be observed by way of gel electrophoresis, and the LAMP assay kit is easy and rapid to operate, and is particularly suitable for field assay in grass roots.

The present invention comprises the identification, characterization and sequencing of a gene within the V. anguillarum genome, the mugA gene, a live, attenuated strain of V. anguillarum which comprises a mutated mugA gene, methods of making the strain, vaccines comprising the strain and methods of making such vaccines and administering the vaccines to animals. The invention further comprises vaccines comprised of proteins encoded by the mugA gene, to methods of making such vaccines and administering the vaccines to animals, to vectors comprised of the attenuated strain of V.anguillarum and additional immunizing materials, methods of making the vectors and methods of administering the vectors to animals. Also disclosed are probes, passive vaccines and monoclonal antibodies for the detection and prevention of vibriosis.

The invention relates to a method for analyzing rice blast resistance gene. The technical scheme of the invention is: 1)searching a property-stable avirulent strain; 2)conversing the strain by agrobacterium-mediated method, inoculating the transformant on near-isogenic lines of rice, getting single-ascospore strain having mutated pathogenicity from susceptible type spot; and 3)return inoculating, identifying and confirming the pathogenicity of the single-ascospore strain, and getting a set of near strains for identifying resistance gene of varieties. The invention can construct a set of rice blast resistance near-isogenic gene stains to deduce resistance gene, directly inoculate stable variety by mutant without using resistance after rice hybridization and inoculation hybridization, as well as allelism test, find out the resistance gene of variety according to the resistance type; and can be used for deducing resistance gene of rice variety containing single or multiple resistance genes.

The invention provides a construction method of a strain not producing aflatoxin and a method for preventing and controlling Aspergillus flavus contamination, wherein the Aspergillus flavus in an avirulent strain does not express pathogenicity-related gene Aflrum1, and the strain is non-toxic, produces no sclerotia and has high sporulation and low pathogenicity. Based on the above characteristicsof the strain, the method for preventing and controlling the Aspergillus flavus by using the strain is further disclosed. More specifically, the method includes the step that with the characteristicsof the non-toxicity, non-bacterial nucleus, high sporulation and low pathogenicity of the strain of Aspergillus flavus used, the strain competes with a wild-produced strain of Aspergillus flavus for alimited niche in a susceptible area of Aspergillus flavus, such as main peanut producing areas. Consequently, the method for preventing and controlling the Aspergillus flavus contamination has the advantages of effectively reducing the density of the wild-produced strains of Aspergillus flavus, effectively controlling and reducing contamination of aflatoxins from crops and aspergillosis infectioninduced thereby.

Chimeric replicons of North American Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) containing the 5′ sequence of an avirulent strain of PRRSV and a 3′ sequence of a virulent strain of PRRSV are provided. Further provided is a method of producing attenuated PRRSV from the chimeric replicon. Also provided are compositions containing the replicon or attenuated virus. Vaccines and a method of vaccinating pigs against PRRSV are also provided.

The present invention is directed to processes and compositions for protecting host animals (e.g., chickens) from exposure to virulent infectious bronchitis virus. In ovo administration of live, avirulent strains of IB at appropriate dosage levels on a per egg basis provides an effective and efficient vaccination having acceptable safety and efficacy features.

Chimeric replicons of North American Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) containing the 5′ sequence of an avirulent strain of PRRSV and a 3′ sequence of a virulent strain of PRRSV are provided. Further provided is a method of producing attenuated PRRSV from the chimeric replicon. Also provided are compositions containing the replicon or attenuated virus. Vaccines and a method of vaccinating pigs against PRRSV are also provided.

The invention relates to a nontoxic ST28 streptococcus suis and an application thereof, and belongs to the biotechnology field. A tonsil sample of a healthy slaughter pig is collected; after bacteria enrichment processing, bacteria DNA (deoxyribonucleic acid) is extracted; a cps2j gene is identified by polymerase chain reaction; then, pure culture bacteria can be obtained by bacteria plate separation; the pure culture bacteria is subjected to gram stain, serum agglutination, polymerase chain reaction and multilocus sequence typing to determine and separate type-2 bacterial strain of the streptococcus suis and a sequence type thereof; animal experiments of a Balb / c mice, a New Zealand rabbit and a Landrace piglet prove that the bacteria HA0609 is a nontoxic bacterial strain; after the bacteria is subjected to intramuscular injection into the New Zealand rabbit for one time and is subjected to intraperitoneal injection into a CD1 mice for two times, certain immunocompetence can be provided for an immunized animal, and analysis on a HA0609 immune protection antigen can be used for developing streptococcus suis disease subunit vaccine.

The invention relates to the field of wheat disease resistance, and specifically relates to a BFR protein associated with resistance of wheat to powdery mildew as well as a coding gene and applicationthereof. The BFR protein associated with resistance of wheat to powdery mildew has an amino acid sequence as shown in sequence 7, or a sequence constructed by replacing one or more amino acids in theamino acid sequence shown in sequence 7. Expression of the BFR protein in wheat leaves is reduced by adopting a virus-induced gene silencing technology and a CRISPR / Cas9 gene editing technology so asto have reaction type of infection of a powdery-mildew-resistant wheat variety, xiao-bai-dong (Triticum aestivum L.), on an avirulent strain E18 changed from grade 0-1 to grade 3-4. Over-expression of the BFR gene in wheat leaves is allowed by adopting biolistic transformation; and thus, pathogen spore germination of a virulent strain E18 on leaves of the wheat variety Kelong-199 is significantlyinhibited.

The invention discloses a method for expanding reproduction of ralstonia solanacearium bacteriophage. An avirulent ralstonia solanacearium strain RSsw326-2 disclosed by the invention is preserved in CCTCC (China Center for Type Culture Collection) and has the preservation number of CCTCC NO. M 2018197. The avirulent ralstonia solanacearium disclosed by the invention is ralstonia solanacearium obtained by separating from naturally infected tobacco plants; by subculture, dissociant is obtained; by pathogenicity determination, the dissociant losing pathogenicity for tobacco seedlings is the ralstonia solanacearium avirulent strain; when the avirulent ralstonia solanacearium avirulent is utilized to reproduce the ralstonia solanacearium bacteriophage, the ralstonia solanacearium bacteriophagewith a high titer can be obtained. The method is expected to be used as a carrier for greatly expanding reproduction of the bacteriophage in the ralstonia solanacearium bacteriophage biological pesticide development so as to avoid secondary damage to prevention and control objects due to the toxicity of a host strain.

The invention discloses application of a composition of an avirulent toxoplasma strain and a traditional Chinese medicine polysaccharide adjuvant, and a vaccine and a preparation method thereof. The traditional Chinese medicine polysaccharide adjuvant can be cooperated with the immune activation effect of toxoplasma via immune synergism for multi-target high-efficiency activation of certain specific anti-tumor immunoregulation pathways, especially anti-tumor immunoregulation pathways related to immune activation of cytotoxic T-cells. The composition can be used for treating tumors and preparing biological drugs used for treating tumors, especially for treatment of gastrointestinal tumors; and in particular, the composition has substantial treatment effect on bile duct carcinoma.

Chimeric replicons of North American Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) containing the 5' sequence of an avirulent strain of PRRSV and a 3' sequence of a virulent strain of PRRSV are provided. Further provided is a method of producing attenuated PRRSVfrom the chimeric replicon. Also provided are compositions containing the replicon or attenuated virus. Vaccines and a method of vaccinating pigs against PRRSV are also provided.

The invention relates to a method for inducing resistance to bacterial wilt of eucalyptus by using a mixture of benzothiadiazole (BTH) and non-pathogenic Ralstonia solanacearum strain (AXY22) at a volume ratio of 1:1. Spraying eucalyptus seedlings with this mixture inducer, supplemented with Tween as a penetrating agent, can significantly improve the resistance of eucalyptus to bacterial wilt, which is economical, simple and easy to implement, and is environmentally friendly and does not cause resistance to the disease And sustainable application, to achieve the purpose of disaster reduction.

The invention provides live attenuated avirulent strains of Francisella tularensis, as well as methods for their preparation and use in protecting a mammal against infection with F. tularensis and against tularemia.

The invention discloses a recombined foot-and-mouth disease virus avirulent strain with stable inheritance of heat-resistant phenotype and a negative marker and an O / A type foot-and-mouth disease bivalent inactivated vaccine. The present invention constructs FMDV virus cDNA infectious cloning plasmid, which carries the molecular determinants of the heat-resistant phenotype of the virus capsid, the molecular factors of losing the replication ability in vivo, the negative marker factors of the deletion of 3A and 3B protein epitopes, and the coding in P1 The introduction of Pst I enzyme cutting sites on both sides of the region can quickly construct and rescue a heat-stable and marked avirulent strain of foot-and-mouth disease virus by replacing its capsid protein coding region for any epidemic strain, and can be used as a seed virus for foot-and-mouth disease inactivated vaccine. Use this general-purpose plasmid to construct two strains of recombinant viruses against the current two dominant epidemic strains and use them to prepare O / A type foot-and-mouth disease bivalent inactivated vaccines, immunize animals to induce high levels of neutralizing antibodies and produce immune protection; use this vaccine to vaccinate animals for antibody The assay enables the differential diagnosis of vaccinated animals from naturally infected animals.

Belonging to the field of biotechnology, the invention discloses a specific molecular marker primer for identification of phytopthora sojae avirulence gene PsAvr1k and a method. The specific molecular marker primer pair has an upstream primer nucleotide sequence shown as SEQ ID No.3 and a downstream primer nucleotide sequence shown as SEQ ID No.4. Through the molecular marker PCR amplification by means of the molecular marker can rapidly and efficiently detect whether a field phytopthora sojae strain is a PsAvr1k virulent strain or avirulent strain. The research not only can be used for studying the distribution of PsAvr1k avirulence gene in the field, but also can reveal the pathotype differentiation variation characteristics of the phytopthora sojae PsAvr1k, and provides the basis for making of a resistant variety selection strategy.

The invention relates to the field of wheat disease resistance, and specifically relates to a BFR protein associated with resistance of wheat to powdery mildew as well as a coding gene and applicationthereof. The BFR protein associated with resistance of wheat to powdery mildew has an amino acid sequence as shown in sequence 7, or a sequence constructed by replacing one or more amino acids in theamino acid sequence shown in sequence 7. Expression of the BFR protein in wheat leaves is reduced by adopting a virus-induced gene silencing technology and a CRISPR / Cas9 gene editing technology so asto have reaction type of infection of a powdery-mildew-resistant wheat variety, xiao-bai-dong (Triticum aestivum L.), on an avirulent strain E18 changed from grade 0-1 to grade 3-4. Over-expression of the BFR gene in wheat leaves is allowed by adopting biolistic transformation; and thus, pathogen spore germination of a virulent strain E18 on leaves of the wheat variety Kelong-199 is significantlyinhibited.

The invention discloses a fungus cross detoxification method, which comprises the following steps of: obtaining a part of fungus tissues which can be cultured into a complete individual under the condition that a to-be-detoxified fungus strain in a development state acts for a long enough time under the action of a chemical reagent with an effective concentration and the virus carried by the strain is in a proliferation inhibition state, and detecting and screening a non-toxic strain after regeneration culture; the fungal tissue is a fungal part containing at least one whole genome copy number; the fungi in the development state are in the development state before the sporocarp of the fungi; the chemical reagent comprises one or a combination of more of 5-dihydrouracil DHT, virazole, actinomycete ketone, rifampicin and moroxydine hydrochloride, the fungal tissue comprises one of protoplast, hypha tip and hypha fragment, the fungus cross detoxification method provided by the invention can remove various viruses in the same strain, the detoxification period is short, the rejuvenation effect is good, and the method is suitable for industrial production. The method is also suitable for removing unknown viruses, and can be applied to strain degeneration caused by virus infection and / or preparation of strains with strong rejuvenation.

The invention provides a construction method of a strain not producing aflatoxin and a method for preventing and controlling Aspergillus flavus contamination, wherein the Aspergillus flavus in an avirulent strain does not express pathogenicity-related gene Aflrum1, and the strain is non-toxic, produces no sclerotia and has high sporulation and low pathogenicity. Based on the above characteristicsof the strain, the method for preventing and controlling the Aspergillus flavus by using the strain is further disclosed. More specifically, the method includes the step that with the characteristicsof the non-toxicity, non-bacterial nucleus, high sporulation and low pathogenicity of the strain of Aspergillus flavus used, the strain competes with a wild-produced strain of Aspergillus flavus for alimited niche in a susceptible area of Aspergillus flavus, such as main peanut producing areas. Consequently, the method for preventing and controlling the Aspergillus flavus contamination has the advantages of effectively reducing the density of the wild-produced strains of Aspergillus flavus, effectively controlling and reducing contamination of aflatoxins from crops and aspergillosis infectioninduced thereby.

The invention discloses an LAMP assay kit for identifying virulent and avirulent strains of mycoplasma gallisepticum. A primer group A provided by the LAMP assay kit consists of a primer group a and a primer group b; the primer group a consists of a primer 1 and a primer 2; the primer group b consists of a primer 3 and a primer 4; and the nucleotide sequences of the primer 1, the primer 2, the primer 3 and the primer 4 are sequence 1, sequence 2, sequence 3 and sequence 4 sequentially in a sequence table. An experiment for the LAMP assay kit proves that the primers and the method only need anordinary water bath rather other an expensive PCR (Polymerase Chain Reaction) instrument but have higher sensitivity than PCR assay, moreover, a result does not need to be observed by way of gel electrophoresis, and the LAMP assay kit is easy and rapid to operate, and is particularly suitable for field assay in grass roots.

The invention relates to a nontoxic ST28 streptococcus suis and an application thereof, and belongs to the biotechnology field. A tonsil sample of a healthy slaughter pig is collected; after bacteria enrichment processing, bacteria DNA (deoxyribonucleic acid) is extracted; a cps2j gene is identified by polymerase chain reaction; then, pure culture bacteria can be obtained by bacteria plate separation; the pure culture bacteria is subjected to gram stain, serum agglutination, polymerase chain reaction and multilocus sequence typing to determine and separate type-2 bacterial strain of the streptococcus suis and a sequence type thereof; animal experiments of a Balb / c mice, a New Zealand rabbit and a Landrace piglet prove that the bacteria HA0609 is a nontoxic bacterial strain; after the bacteria is subjected to intramuscular injection into the New Zealand rabbit for one time and is subjected to intraperitoneal injection into a CD1 mice for two times, certain immunocompetence can be provided for an immunized animal, and analysis on a HA0609 immune protection antigen can be used for developing streptococcus suis disease subunit vaccine.

The invention relates to a molecular method for determining virulence of phytophthora sojae on a disease-resistant gene (i)Rps3a( / i)(Chapman), comprising the steps: extracting genome DNA of phytophthora sojae to be detected, carrying out PCR amplification to obtain a DNA fragment containing avirulence gene(i)Avr3a( / i), carrying out enzyme digestion with restriction enzyme (i)Bpu( / i)10I, carrying out agarose gel electrophoresis on the enzyme digestion product to obtain an agarose gel electrophoretogram of the enzyme digestion product; and observing the agarose gel electrophoretogram of the enzyme digestion product, if 2 DNA bands exist in a 250bp-500bp range, the corresponding phytophthora sojae strain to be detected is an avirulent strain, and if 1 DNA band exists under 750bp in the electrophoretogram after enzyme digestion, the corresponding phytophthora sojae strain to be detected is a virulent strain. The method has the advantages of short determination cycle, no intermediate type, accuracy and reliability, and can determine with a high flux reactor the virulence of phytophthora sojae on the disease-resistant gene (i)Rps3a( / i)(Chapman).