35 results about "Avirulent strain" patented technology

Specific genetic deletion are identified in mycobacteria isolates, including variations in the M. tuberculosis genome sequence between isolates, and numerous deletion present in BCG as compared to M. tb. These deletions are used as markers to distinguish between pathogenic and avirulent strains, and as a marker for particular M. tb isolates. Deletions specific to vaccine strains of BCG are useful in determining whether a positive tuberculin skin test is indicative of actual tuberculosis infection. The deleted sequences may be re-introduced into BCG to improve the efficacy of vaccination. Alternatively, the genetic sequence that corresponds to the deletion(s) are deleted from M. bovis or M. tuberculosis to attenuate the pathogenic bacteria.

The present invention relates to nucleic acids encoding B. mallei and B. pseudomallei AHL synthases and LuxR transcriptional regulators, and methods for use, as well as describes the construction, characterization and use of avirulent strains of B. mallei and methods of use.

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.

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 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 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.

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.