253 results about "Operon" patented technology

The invention discloses construction and application of a CRISPR/Cas9 gene editing vector for microorganisms. The constructed CRISPR/Cas9 gene vector consists of a replication start site, a selection marker gene, a Cas9 protein gene, gRNA coding DNA, a homologous recombinant element and an operon. The CRISPR/Cas9 gene vector constructed by the invention is capable of editing (including performing such operations as knocking out, replacing, interpolating and the like on gene or DNA sequence) escherichia coli or corynebacterium glutamicum genome; and the gene vector has the advantages of being short in test cycle, time-saving and cost-saving, high in efficiency and the like.

An intracellular selection system allows screening for peptide bioactivity and stability. Randomized recombinant peptides are screened for bioactivity in a tightly regulated expression system, preferably derived from the wild-type lac operon. Bioactive peptides thus identified are inherently protease- and peptidase-resistant. Also provided are bioactive peptides stabilized by a stabilizing group at the N-terminus, the C-terminus, or both. The stabilizing group can be a small stable protein, such as the Rop protein, glutathione sulfotransferase, thioredoxin, maltose binding protein, or glutathione reductase, an α-helical moiety, or one or more proline residues.

The invention provides a genetic engineering bacterium capable of producing uridine at high yield as well as a building method and application thereof. The genetic engineering bacterium is characterized in that pyrimidine nucleoside operons pyrBCAKDFE with the nucleotide sequence shown as SEQ ID NO:1 is integrated on a genome of colon bacillus; the starting is realized by a strong promoter P[trc];a uridine synthesis path is reconstituted; the self PRPP synthetase coding gene prsA on the genome is subjected to dual copying, and the starting is realized by the strong promoter P[trc]; meanwhile,the activity of udk, udp, and rihA, rihB and rihC is lacked; the thrA activity is lacked; the argF activity is lacked. The genetic engineering bacterium is applied to fermentation production of uridine; 40 to 67g/L of uridine can be produced after the fermentation is performed for 40 to 70h in a 5L fermentation tank; the maximum production intensity can reach 1.5g/(L*h); the glucoside conversionrate is 15 to 25 percent; the genetic engineering bacterium belongs to the highest level for producing the uridine by the fermentation method reported in the prior art.

The invention relates to escherichia coli CGMCC NO.3192 for recombined engineering and a variant thereof. The strain is obtained by integrating gene segments subjected to the recombined engineering, i.e. a regulatory gene araC of the Arabinose ara operon from the escherichia coli, a promoter pBAD of the Arabinose ara operon from the escherichia coli, recombined enzyme genes red alpha, red alpha beta and gam from a gamma bacteriophage, a gene recA and gentamicin resistance gene (Gm) from the escherichia coli, into an endA gene area of a gene group of the escherichia coli DH10B, wherein red alpha, red alpha beta, gam and recA are driven by pBAD induced by arabinose. The recombined enzyme can catalyze homologous recombination among DNA short segments to finish the recombined engineering. The length of the DNA segment is about 50 base pairs. The invention has convenient operation of carrying out the recombined engineering by the strain and high recombined efficiency, thereby becoming the universal strain for the recombined engineering.

The invention discloses a lactoflavin engineering bacterium and a constructing method thereof, and the preservation number of the lactoflavin engineering bacterium is CGMCC NO.16132. Through a geneticengineering means, a lactoflavin auxotroph strain is constructed, then a chromosome integrates and expresses a lactoflavin operon demodulated by bacillus amyloliquefaciens, and the lactoflavin production capacity of the strain is restored; then an expression vector overexpresses the lactoflavin operon demodulated by the bacillus subtilis, so that the lactoflavin production capacity of the straincan be improved; in addition, through point mutation of a ribC gene, the catabolism of lactoflavin is diminished; and finally, a recA gene which is responsible for homologous recombination and DNA repair on the chromosome is inserted for inactivation, and a lactoflavin production chassis cell is constructed. Based on the lactoflavin production chassis cell, through combination of the characteristic that the lactoflavin is a natural flroresence substance, and a strain high in lactoflavin yield is screened out through liquid drop micro-fluidic control. The invention also discloses a method for producing the lactoflavin through fermentation with the bacillus subtilis, and an application of the strain high in lactoflavin yield to lactoflavin production and an application of the strain high inlactoflavin yield to medicines, foods and feeds.

An intracellular selection system allows concurrent screening for peptide bioactivity and stability. Randomized recombinant peptides are screened for bioactivity in a tightly regulated expression system, preferably derived from the wild-type lac operon. Bioactive peptides thus identified are inherently protease- and peptidase-resistant. Also provided are bioactive peptides stabilized by a stabilizing group at either the N-terminus, the C-terminus, or both. The stabilizing group can take the form of a small stable protein, such as the Rop protein, glutathione sulfotransferase, thioredoxin, maltose binding protein, or glutathione reductase, or one or more proline residues.

The invention relates to an operon encoding enzymes involved in the utilization of L-arabinose, to the promoter derived therefrom, and to expression systems utilizing the promoter. The promoter is particularly useful for expression of DNA sequences in prokaryotes because of their inducibility and repressibility of the promoter. The invention also relates to the enzymes of the operon, and antibodies thereto.

The present invention provides a method for producing an L-amino acid using a bacterium of the Enterobacteriaceae family, particularly a bacterium belonging to the genus Escherichia or Pantoea, which has been modified to enhance expression of at least one gene of the fucPIKUR operon.

The invention discloses recombinant zymomonas mobilis capable of producing ethanol by using xylose and a fermentation method thereof. The recombinant zymomonas mobilis GX1 capable of producing the ethanol by using the xylose is preserved in China General Microbiological Culture Collection Center, and has a preservation number of CGMCC 3438. The controlling elements of Escherichia coli rrnB and related genes of xylose metabolism are fused to build plasmids with artificially fused operons for the first time; and recombinant zymomonas mobilis strains capable of producing the ethanol by using the xylose are obtained through a method of electrotransformation and acclimatization. The recombinant zymomonas mobilis can efficiently express exogenous genes, can efficiently produce the ethanol by using glucose and the xylose to ferment together at the temperature of between 30 and 34 DEG C, and can produce the ethanol by using corncob hydrolysate containing the xylose and the glucose. The strains have important significance for producing clean energy by effectively using waste lignocellulose and solving the current energy crisis.

The present invention relates to methods and compositions for the size-adjusted recombinant production of magnetic nanoparticles. More particular, the invention relates to a method, comprising: providing one or more cells being capable of producing magnetic nanoparticles; modifying in the one or more cells the expression of one or more genes involved in the formation of the magnetic nanoparticles; cultivating the modified cells obtained in step (b); and isolating the magnetic nanoparticles from the cultivated cells, wherein the magnetic nanoparticles have a defined size. In preferred embodiments, the method comprises modifying the expression of one or more genes of the mamGFDC operon in magnetotactic bacterial cells. The invention is further directed to host cells bearing said modifications, the recombinant magnetic particles isolated from such cells as well as to the use of such particles for the detection and/or separation of biomolecules or as a contrast agent in magnetic resonance imaging.

A method is described for producing an L-amino acid, for example L-threonine, L-lysine, L-leucine, L-histidine, L-cysteine, L-phenylalanine, L-arginine, L-tryptophan, L-glutamic acid, L-valine, and L-isoleucine, by fermentation of glucose using a bacterium of the Enterobacteriaceae family, wherein the bacterium has been modified to enhance the activity of the high-affinity arabinose transporter coded by the araFGH operon.

Macrolide resistance associated with macrolide efflux (mef) in Streptococcus pneumoniae has been defined with respect to the genetic structure and dissemination of a novel mefE-containing chromosomal insertion element. The mefE gene is found on the 5′-end of a 5.5 kb or 5.4 kb insertion designated mega (macrolide efflux genetic assembly) found in at least four distinct sites of the pneumococcal genome. The element is transformable and confers macrolide resistance to susceptible S. pneumoniae. The first two open reading frames (ORFs) of the element form an operon composed of mefE and a predicted ATP-binding cassette homologous to msrA. Convergent to this efflux operon are three ORFs with homology to stress response genes of Tn5252. Mega is related to mefA-containing element Tn1207.1. Macrolide resistance due to mega has been rapidly increased by clonal expansion of bacteria containing it and horizontally by transformation of previously sensitive bacteria.

The invention discloses a method for improving the yield of vernine from bacillus amyloliquefaciens. The method comprises the following steps: by taking thermo-sensitive type plasmid pKS2 as a carrier, removing a promoter partial segment of a purine operon (purEKBCSQLFMNHD) through adopting a homologous recombination method, wherein the preferable sequence segment is -193bp to -29bp segment of the purE-deleted gene, and the repression effect of purR (repressor protein of the purine operon) and the transcription attenuation action caused by the palindrome structure of the segment of a strain with the segment deleted are removed; and desensitizing transamidase gene of purF coded phosphoribosyl pyrophosphate (PRPP) through point mutation, wherein preferably, leucine at 217th site is mutated into isoleucine (L217I), and the feedback inhibition from products adenosine and vernine can be removed. The production capability of the transformed genetically engineered bacterium vernine is obviously improved.

The invention discloses a recombinant bacillus subtilis of high-yield pullulanase and a construction method thereof. The construction method of the recombinant bacillus subtilis of the high-yield comprises the following steps that an artificial operon BPB used for expressing the pullulanase is used for constructing a recombinant plasmid pGE-BPB; the nucleotide sequence of the artificial operon BPB is shown in the graph SEQ ID NO.4; the constructed recombinant plasmid pGE-BPB is converted into a bacillus subtilis competent cell, and through secondary recombination, a neutral protease gene nprE in the bacillus subtilis competent cell is replaced by the artificial operon BPB in situ. According to the recombinant bacillus subtilis of the high-yield pullulanase and the construction method thereof, firstly, the acidproof and heatproof pullulanase gene of an original bacterial strain is optimized, based on the synthetic biology method, a plurality of molecular elements capable of improving the gene transcriptional level are assembled into the artificial operon, and the recombinant bacillus subtilis can be obtained through construction. The recombinant bacterial strain can ferment to generate the high-yield pullulanase, and the enzyme activity each unit can reach or exceed 300 U/ml.

The invention discloses a bacillus subtilis strain for producing high-purity chiral D-(-)-2,3-butanediol, and construction and applications. The construction method comprises the steps of: in bacillus subtilis, knocking out acoA gene in a degradation path of direct substrate acetoin of 2,3-butanediol, knocking out encoding gene bdhA of acetoin reductase, knocking out pta gene in a side product acetic acid formation path, knocking out ldh gene in a side product lactic acid formation path, overexpressing a synthetic branch alsSD operon by using a P43 strong promoter, overexpressing dehydrogenase encoding gene bdhA of D-(-)-2,3-butanediol by using a P43 strong promoter, and overexpressing transhydrogenase encoding gene udhA in reducing power balancing process by using a P43 strong promoter. The constructed bacillus subtilis strain is safe and harmless, and the D-(-)-2,3-butanediol, with the chiral purity of more than 99%, can be produced by utilizing glucose as a substrate.

A system for ligase-free cloning and/or expressing a target gene is described herein. A preferred version of the invention includes an E. coli host. The host preferably includes a T7 RNA polymerase gene comprising a T7gpl coding sequence, a lacUV5 promoter, and a lac operator. The host preferably further includes a lacI gene comprising a lacI coding sequence with an ATG start codon, a promoter derived from the lac^ql allele, and a translational enhancer derived from a 5′ RNA leader sequence of T7 gene 10. The invention further includes a low-copy plasmid vector comprising a T7 promoter a lac operator operationally linked to the T7 promoter. The system is configured to inhibit target gene expression when uninduced and to permit gene expression upon induction by auto-induction.