54 results about "Chloramphenicol Resistance" patented technology

The invention provides a recombinant vector for eliminating the activity of a kanamycin drug resistance gene, and aims at eliminating drug resistance germs in organisms and solving the problem of kanamycin drug resistance of the germs. The recombinant vector for eliminating the activity of the kanamycin drug resistance gene is characterized by comprising a pCas9 vector subjected to chloramphenicol resistance elimination and a gRNA nucleotide sequence KR58 or KR208 aiming at a kanamycin resistance gene kan; the concrete nucleotide sequence of the KR58 is GCCGCGAT TAAATTCCAACA, and the concrete nucleotide sequence of the KR208 is CAATGATG TTACAGATGAGA. A building method of the recombinant vector mainly comprises the steps of carrying intergenic region nucleic acids by a novel gene editing tool CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)/Cas9 system; removing a chloramphenicol resistance gene on the recombinant vector; transforming the gene into vaccine vector bacteria such as attenuated salmonella typhimurium; performing co-culture on the recombinant bacteria and the kanamycin drug resistance gene so that the recombinant vector in the recombinant bacterium cell enters the kanamycin drug resistance bacteria in an engaging mode. The activity of the kanamycin resistance gene kan is effectively inhibited, so that the original drug resistance bacterium cannot grow on a kanamycin culture medium.

The invention relates to a bacillus subtilis strain for excreting nattokinase at high efficiency. An aprN gene of bacillus subtilis NK is amplified by a PCR (polymerase chain reaction) technique; codons of initial thirty amino acids are optimized according to the codon preference of the bacillus subtilis, a recombination expression plasmid pHT01-aprN is established, and the correctness is verified through the restriction enzymes digestion, PCR amplification and sequencing. The recombination expression plasmid pHT01-aprN is imported into the bacillus subtilis 168 by an electric shocking method, and is performed with resistance screening by adopting chloramphenicol, so as to obtain engineering bacteria. After the fermenting condition is optimized, and the expression is induced by IPTG, the highest enzyme activity in a shake culture fermenting liquid is 289U/ml; the highest enzyme activity in a high-density fermenting liquid is 7778U/ml; the highest enzyme activity of a nattokinase preparation prepared by affinity column chromatography is 981731U/g.

The invention discloses a single-resistance escherichia coli-bacillus subtilis shuttle expression vector and application thereof. The bacillus subtilis shuttle expression vector provided by the invention comprises the following elements: a bacillus subtilis formed strong promoter P43, a sequence which encodes signal peptide, multiple cloning sites, an antibiotics resistance gene (kalamycin or chloramphenicol), a bifunctional promoter sequence which can start resistance gene expression of kalamycin or chloramphenicol in escherichia coli and bacillus subtilis, and copy homing sequences of bacillus subtilis and escherichia coli. The expression vector disclosed by the invention not only can be stably copied in escherichia coli, but also can be stably copied in bacillus subtilis, and expresses homologous and heterologous proteins. All vectors just contain one resistance gene, the plasmid of which is less than 400bp, so that gene operation and plasmid conversion are easy to carry out, and the conversion ratio is high. Besides the expression vector of an exogenous gene, the vector can be further used for screening promoters and constructing a gene knock-out vector.

The invention discloses a universal gene-knockout suicide vector for vibrios and a construction method theroef and provides an application thereof in gene knockout of the vibrios. The universal gene-knockout suicide vector pLP12 is a ring-shaped vector and comprises a PBAD promoter, a repressor protein gene araC, an RP4 transferring initiation site, a chlorampenicol resistant gene, an R6K duplicating initiation site, a multiple-cloning-site area and a lethal gene vmi480; the multiple-cloning-site area at least contains two AhdI restriction enzyme digestion sites; the suicide vector pLP12 is subject to AhdI restriction enzyme digestion to form linearized suicide vector pLP12T. The universal gene-knockout suicide vector adopts entirely-new reverse selection genes vmi480 and is used for replacing the common sacB gene. Foreign fragments carried by the pLP12T are transferred to vibrio cells to be mutated by a jointing mode, under the pressure of antibiotics and reverse selection of products of lethal gene vmi480, first-time homologous recombination and second-time homologous recombination are carried out on the vibrios successively, and finally the mutant strain with deletion of target genes is generated.

The invention refers to a method for reconstructing the cloned and constructed human body tumor death factor TRAIL gene expression carrier into spirulina gene group to be expressed stably with gene gun. The special components of the reconstructed TRAIL expression carrier include resistant mark gene expression box CAT, chlorophyll body photosynthetic gene promotor and ender, spirulina homologous segment, TRAIL gene segment without coding film combining part, the expression system also includes characters of primary nucleus and eukarya. The invention sets suitable striking parameter, uses gene gun to guide the reconstructed expression carrier into spirulina silk body, and through several times of sifting of chloramphenicol with incremental density and molecular biology testing, the invention gets spirulina converter of TRAIL gene. The invention applies to spirulina reconstruction and human body gene expression, it also applies to reconstruct and express other primary nucleolus and eukarya.

The invention discloses an enhance-like element gene ER1 for enhancing foreign protein expression in prokaryotic cells. The enhance-like element gene has a nucleotide sequence as shown in SEQ ID NO: 1 (Sequence Identity No) or a truncated sequence of the nucleotide sequence, wherein the gene sequence is screened by establishing a fusion expression reporter gene recombinant vector; the fusion reporter gene consists of major capsid protein L1 gene of human papilloma virus and chloramphnicol acetyltransferase (CAT); the gene fragments to be selected are linked with the sieving recombinant vector and is transformed so as to establish a gene library; and the recombinant bacterial strain containing the enhance-like element gene sequence is screened based on the chloramphenicol resistance, so as to obtain the enhance-like element sequence which can improve the activity of chloramphenicol of the fusion reporter gene of the strain and promotes the foreign protein expression.

The invention relates to a preparation method of radioresistant bacterium that contains the activity of luciferase. The invention takes plasmids originating from radioresistant bacterium deinococcus radiopugnans as a base to recompose with plasmids that can ensure self-duplication in escherichia coli to form a shuttle carrier. The carrier is recomposed with DNA fragments in the luciferase gene lux field that originates from into host DNA of photinus pyralis from North America into plasmids with luciferase genes. Then the plasmids are introduced into bacterial of a radioresistant bacterium family, deinococcus grandis are transformed by the constructed plasmids to get chloramphenicol resistant strains. The radioresistant bacterium prepared by the method of the invention can be used in various fields of outdoor opening and close environments. The carrier has the luciferase genes, thereby having better application value to real-time supervision and control on the propagation, distribution and influence to the environment of the recomposed transformants.

The invention relates to a zymomonas mobilis gene engineering bacterium capable of producing isobutanol and a construction method of the zymomonas mobilis gene engineering bacterium. A 2-ketoisovalerate decarboxylase (kivd) gene and an alcohol dehydrogenase (adhA) gene in Lactococcus lactis 1.2829 can be obtained through cloning and connected to plasmid pZY507 with chloramphenicol resistance for construction to obtain recombinant plasmid pZY507KA, the recombinant plasmid is electro-transformed into zymomonas mobilis, and bacterial strains with chloramphenicol resistance are screened to be the target engineering bacterium. The obtained gene engineering bacterium can decompose glucose to synthesize the isobutanol after the engineering bacterium is induced, a zymomonas mobilis fermentation method is firstly used for producing the isobutanol, and simultaneously, huge potential and values of the zymomonas mobilis are shown.

The invention discloses a small shuttle plasmid pSDU1 with a chloramphenicol resistant gene for Acidithiobacillus caldus, which consists of a replicor oriV, an auto-replicating protein gene rep, a conjugational transfer gene mob, a chloramphenicol resistance selection gene cat and a multiple cloning site (MCS). The plasmid pSDU1 uses chloramphenicol resistance as a selection marker and has higher conversion efficiency; the multiple cloning sites of the plasmid pSDU1 are introduced, and the use is convenient; the oriV, rep and mob parts of the plasmid pJRD 215 is used, so higher stability is achieved; and the length of the plasmid is only 6.4kbp and the bearing capacity of the plasmid is higher, which indicate the plasmid has a huge application potential in molecular biological research and genetic engineering modification of the Acidithiobacillus caldus.

The invention discloses a streptococcussuis serotype 2 SsnA gene knockout mutant strain, and a preparation method and an application of the mutant strain. The mutant strain is formed by substituting an SsnA gene in a streptococcussuis serotype 2 SS2-GD01 strain with a chloramphenicol resistant gene cassette CAT. The mutant strain is preserved in China Center for Type Culture Collection (CCTCC) with a preservation number of CCTCC NO: M2014539 on October 31, 2014. The growth characteristic of the SS2-GD01 SsnA strain is similar to a wild strain; the adhesion and invasion capacity of the SS2-GD01 SsnA strain on an Hep-2 cell in vitro is obviously reduced; the virulence of the SS2-GD01 SsnA strain is obviously reduced compared with the wild strain; SsnA participates in a pathopoiesis process of streptococcussuis serotype 2 and is a new virulence correlation factor; and the mutant strain provides an important clue for screening of protective antigens of multivalent subunit vaccine, and can be applied to research and development of streptococcussuis serotype 2 attenuated vaccine.

The invention relates to a shuttle vector beneficial to construction of long fragment DNA and a preparing method and application thereof. The shuttle vector is capable of shuttling back and forth in saccharomyces cerevisiae and escherichia coli, and has a saccharomyces cerevisiae replication origin oriV and an escherichia coli replication origin ori2, both the oriV and the ori2 are low-copy replication origins, and the shuttle vector can conduct stable replication in both the saccharomyces cerevisiae and the escherichia coli, a screening label in the saccharomyces cerevisiae is HIS3, and the screening label in the escherichia coli is chlorampenicol resistance. According to the shuttle vector beneficial to the construction of long fragment DNA and the preparing method and application thereof, the constructed saccharomyces cerevisiae-escherichia coli shuttle vector (named pSynoYAC0) is capable of being successfully assembled in a yeast system, however, plasmid extracted from the saccharomyces cerevisiae has poor quality, while the plasmid extracted from the escherichia coli has high quality, thus further experiment demands such as sequencing and enzyme digestion can be satisfied. The shuttle vector is also capable of conducting replication in the escherichia coli, and the replication belongs to a single copy; meanwhile, the shuttle vector is capable of existing stably in the replication process, thus the vectors meeting the demands can be obtained.

The present disclosure provides novel compositions and methods for the production and use of Agrobacterium tumefaciens strains (for example LBA4404) that are deficient in RecA activity relative to the parent strain. Combinations with other gene-deficient-strains of Agrobacterium tumefaciens are also disclosed. Specifically, two exemplary s recA minus strains, UIA777 where chloramphenicol resistant gene disrupting the recA gene and UIA770 where kanamycin resistant gene disrupting the recA gene are provided.

The invention relates to an escherichia coli-streptomycete shuttle-type BAC vector and its construction method. The BAC carrier contains multiple cloning sites (MCS), an Am resistant gene, an intergrase gene int, an integrate site attp, conjugal transfer fragments oriT and oriS, a repA gene, a sopA gene, a sopB gene, a sopC sequence, a cos site and a loxP site of replication region of the BAC vector. Beginning with pBeloBAC11, a Red homologous recombination technology is used to replace the above chloramphenicol resistant gene with DNA fragment of oriT-attp-int-Am for conjugal transfer (oriT), site-specific integration (attp-int) and resistance screening (Am) so as to obtain a vector pBTIBAC1. Thus, a foundation is established for realizing heterogeneous expression of large fragments of gene clusters in streptomycete.