167 results about "Polymyxin" patented technology

The invention belongs to the technical field of gene engineering, and particularly relates to a mutant of polymyxin efflux transporter and application of the mutant. The mutant is a PmxD transporter mutant, the amino acid sequence of the PmxD transporter mutant is shown as SEQ ID NO: 1, and compared with wild type PmxD, the polymyxin transport capacity of the PmxD transporter mutant (T38W) is improved by 450.46%; and the total discharge amount of polymyxin is increased by 85.72%. Meanwhile, the mutant can significantly improve the growth ability of the strain on a plate containing 250 [mu] g / mL of polymyxin B, namely significantly improve the autoresistance of paenibacillus polymyxa to polymyxin.

The invention discloses an application of NSC348884 in preparation of an antibacterial drug, the bacteria of the NSC348884 are gram-negative bacteria or drug-resistant gram-negative bacteria, and the gram-negative bacteria are acinetobacter baumannii, escherichia coli, pseudomonas aeruginosa or klebsiella pneumoniae; based on an antibacterial drug high-throughput screening technology, it is found from 1280 small molecule compounds that the benzimidazole compound NSC348884 has direct bacteriostasis and sterilization effects on gram-negative bacteria and drug-resistant gram-negative bacteria, and no drug resistance is generated after the benzimidazole compound NSC348884 is continuously applied for 14 days. Further research shows that NSC348884 can interfere with lipid synthesis of gram-negative bacterium cell membranes, inhibit formation of biological membranes and induce lipid metabolism disorder, so that bacteriostatic and bactericidal effects are achieved. In addition, the NSC348884 can also enhance the sensitivity of the drug-resistant bacteria to the imipenem and the polymyxin B.

The invention provides a fluorenyl alcohol derivative which can be used as an antibiotic adjuvant with a broad-spectrum synergistic effect. According to the compound, bacteria outer membrane asymmetric protein MlaC and phospholipase A1 PldA are taken as targets, and a series of fluorenyl alcohol derivatives targeting the bacteria outer membrane asymmetric protein MlaC and phospholipase A1 PldA are obtained through screening. The preferable compound WTU-15 can improve the antibacterial activity of antibiotics such as polymyxin, cefepime, tetracycline and the like on negative bacteria such as sensitive and drug-resistant escherichia coli, salmonella, klebsiella pneumoniae, acinetobacter baumannii and the like, and can also improve the in-vivo treatment effect of cefepime on mice infected by the drug-resistant acinetobacter baumannii. And the visceral organs of the mice survived after administration have fewer bacteria, and the mice are better after being healed. Normal physiological and visceral organ functions of the mouse are not affected by single and continuous administration of the WTU-15.

The invention provides a pharmaceutical composition, glycyrrhizic acid and polymyxin B self-assembled carrier-free hydrogel as well as a preparation method and application thereof, and belongs to the technical field of biological medicines. The invention provides a pharmaceutical composition. The pharmaceutical composition comprises glycyrrhizic acid and polymyxin B. According to the pharmaceutical composition, the inhibition effect on MRSA is enhanced through drug combination, the use of polymyxin B is reduced through the synergistic effect, and the development pressure of antibiotic drug resistance is relieved. According to the hydrogel formed by crosslinking the glycyrrhizic acid and the calcium chloride, the glycyrrhizic acid and the calcium chloride are crosslinked to form the hydrogel, and the calcium chloride is introduced into a glycyrrhizic acid system to increase the mechanical strength of the glycyrrhizic acid hydrogel, so that the glycyrrhizic acid hydrogel can be better attached to a wound. The invention provides a glycyrrhizic acid and polymyxin B self-assembled carrier-free hydrogel and a preparation method of the glycyrrhizic acid and polymyxin B self-assembled carrier-free hydrogel. The hydrogel does not contain any inert carrier component at all, the drug loading rate of 100% is achieved, and adverse reactions possibly caused by a traditional carrier system are effectively avoided.

The invention discloses a bacteriophage lyase and application thereof, and particularly relates to a bacteriophage lyase with an amino acid sequence as shown in SEQ INNO.2. The bacteriophage lyase can inhibit the growth of escherichia coli, staphylococcus and salmonella, can be used as an antibacterial substance in splitting gram-negative bacteria and can be used for preparing drugs for resisting gram-negative bacteria. The lyase can be used independently or compounded with other substances, the use concentration of antibiotics can be reduced by combining the lyase with the antibiotics, toxic and side effects (such as renal toxicity of polymyxin) of drugs are reduced, and meanwhile, generation of bacterial drug resistance is delayed. After the lyase and the chitosan are combined for use, remarkable antibacterial activity is generated, the antibacterial effect can be achieved without pre-treatment on bacteria, and the practicability is improved.

The invention relates to dsRNA capable of simultaneously preventing and treating various thrips and application of the dsRNA. Specifically, the invention provides a dsRNA construct, the construct of the dsRNA is a double strand, and the construct of the dsRNA comprises a nucleotide sequence of an insect nymph and / or adult stage regulation related gene or fragment; wherein the insect nymph and / or adult stage regulation related gene is an Actin gene, and the dsRNA is obtained by amplifying a sequence as shown in SEQ ID NO: 9-10. The fusion type dsRNA is designed to target a plurality of conservative thysanoptera actin gene dsRNA, so that the multi-killing effect is achieved, and the prevention and treatment effect of the fusion type dsRNA is equivalent to that of spinetoram which is commonly used in the market at present.

The invention discloses application of a cyclic peptide compound BIM 23042 or a preparation thereof in preparation of medicines for treating bacterial infectious diseases, and belongs to the technical field of medicines. The invention discloses a cyclic peptide compound BIM 23042 as an antibiotic synergist for the first time, and the cyclic peptide compound BIM 23042 is used for treating bacterial infectious diseases. According to the application disclosed by the invention, the cyclopeptide compound BIM 23042 and polymyxin are combined for use, so that the growth of gram-negative bacteria can be effectively and synergistically inhibited. The combined medication scheme shows a remarkable advantage in coping with acinetobacter baumannii. The cyclic peptide compound BIM 23042 disclosed by the invention has an anti-infection capability, and the anti-infection capability is specifically shown as reducing the inflammatory response of macrophage RAW 264.7 induced by LPS (Lipopolysaccharide) and also reducing the apoptosis of the macrophage RAW 264.7 caused by the LPS. The invention provides a new perspective for developing a novel drug-resistant gram-negative bacterium prevention and control strategy, and also provides a new treatment scheme for coping with bacterial infection.

The invention belongs to the technical field of biology, and provides a pseudomonas aeruginosa endotoxin specific binding polypeptide and application thereof. The amino acid sequence of the polypeptide is shown as SEQ ID No. 1, SEQ ID No. 3 or SEQ ID No. 4 in a sequence table. Experiments prove that the polypeptide has excellent affinity with pseudomonas aeruginosa endotoxin, and compared with an existing anti-endotoxin clinical drug polymyxin B, the polypeptide has obviously better pseudomonas aeruginosa endotoxin detoxification capability. On the basis, the invention further provides application of the polypeptide in removal or separation or analysis of the endotoxin of the pseudomonas aeruginosa and application of the polypeptide in preparation of a detoxification medicine for the endotoxin of the pseudomonas aeruginosa. The polypeptide can be widely applied to the biomedical fields of biological separation, biological detection, disease diagnosis and treatment and the like.

The invention discloses multifunctional double-drug co-loaded nanoparticles as well as a preparation method and application thereof, and belongs to the technical field of medicines. A Janus nano material composed of mesoporous silica and mesoporous polydopamine is respectively loaded with salvianolic acid B and polymyxin B under the condition of pH 4.5 to obtain the double-drug co-loaded nano-particles, the double-drug co-loaded nano-particles have good biocompatibility and synergistic treatment effect, and the double-drug co-loaded nano-particles can reduce active oxygen accumulation and inhibit oxidative stress and inflammatory response, so that the double-drug co-loaded nano-particles can be used for preparing the anti-inflammatory drug for treating the salvianolic acid B and the polymyxin B. The endothelial injury caused by sepsis is effectively relieved. The salvianolic acid B and the polymyxin B are loaded at the same time, the salvianolic acid B protects endothelial cells by removing active oxygen and reducing inflammatory reaction, the polymyxin B kills gram-negative bacteria by destroying bacterial cell membranes and reduces infection sources and endotoxin release, and through the synergistic effect of the salvianolic acid B and the polymyxin B, the blood vessel leakage can be reduced, and the blood vessel leakage can be reduced. And the integrity of the endothelial barrier can be enhanced, so that the aim of treating sepsis endothelial injury is fulfilled.

This invention provides the application of dehydrouncitonin in the preparation of drugs that reduce polymyxin toxicity, belonging to the field of pharmaceutical technology. This invention uses dehydrouncitonin in combination with polymyxin. The combined use of dehydrouncitonin and polymyxin E increased the viability of HEK293T and RAW264.7 cells to 87.7% and 94.3%, respectively, with highly significant differences compared to the control, indicating that treatment with dehydrouncitonin in combination with polymyxin E can significantly inhibit the cytotoxic effect of polymyxin E. This invention uses a mouse model to demonstrate that treatment with dehydrouncitonin in combination with polymyxin E can significantly reduce the neurotoxicity and nephrotoxicity of polymyxin E alone in mice, specifically manifested in improved neurobehavioral effects and improved histopathological effects on brain and kidney tissues. This invention uses dehydrouncitonin in combination with polymyxin E to significantly inhibit the cytotoxic, neurotoxic, and nephrotoxic effects of polymyxin E.

The present application relates to the technical field of biology, and particularly relates to a mesenchymal stem cell culture medium and a preparation method and application thereof.The mesenchymal stem cell culture medium comprises a basic culture medium, fetal bovine serum, basic fibroblast growth factor, polymyxin B and deionized water.The present application can simultaneously improve the proliferation activity of mesenchymal stem cells and the secretion performance of HGF by simultaneously adding the basic fibroblast growth factor and the polymyxin B in the basic culture medium; more stem cells can be in the active proliferation and division process by limiting the content of the basic fibroblast growth factor in the mesenchymal stem cell culture medium to 5-50 ng / mL; and the secretion performance of HGF can be improved while the cell proliferation activity is maintained by limiting the content of the polymyxin B in the mesenchymal stem cell culture medium to 50-100 mu g / mL.

The invention relates to the technical field of biological medicine, in particular to application of flufenamic acid in preparation of a polymyxin E antibacterial synergist. The invention discloses an application of flufenamic acid in preparation of a polymyxin E antibacterial synergist, the flufenamic acid has no obvious antibacterial effect on salmonella when being independently used, but the flufenamic acid and polymyxin E can enhance the antibacterial activity of the polymyxin E on the salmonella and reduce the use dosage of the polymyxin E when being jointly used in and out of an animal body, so that the antibacterial effect of the polymyxin E on the salmonella can be enhanced. The antibacterial activity of the polymyxin E on salmonella is enhanced, and the drug resistance of the polymyxin E is inhibited. Flurfenamic acid is approved to be used for other purposes as FDA, and when the flurfenamic acid is combined with polymyxin E, the flurfenamic acid has the characteristic of high safety, and meanwhile, the generation of the drug resistance of the polymyxin E drugs can be effectively avoided. The invention provides a basis for mining a new antibacterial prevention and control strategy for the polymyxin E drug-resistant bacteria.

This invention discloses a polymyxin-resistant, extended-spectrum β-lactamase-producing *Escherichia coli* strain EC382-2-2 and its applications. The *E. coli* strain EC382-2-2 of this invention was deposited on October 27, 2022, at the Guangdong Provincial Microbial Culture Collection Center (GDMCC), located at 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, Guangdong Province, China, with accession number GDMCC No: 62929. *E. coli* EC382-2-2 simultaneously carries the *eae* virulence gene, the plasmid-mediated polymyxin resistance gene *mcr-1*, the extended-spectrum β-lactamase gene *CTX-M-55*, and other antibiotic resistance genes. *E. coli* EC382-2-2 carries 18 resistance genes and exhibits high-level resistance to multiple antibiotics, making it a promising model strain for screening novel antimicrobial drugs.

The present invention provides an aryliminothiazole compound represented by Formula I or a pharmaceutically acceptable salt thereof, as well as a preparation method and use thereof. These compounds or pharmaceutically acceptable salts thereof can simultaneously enhance the activity of polymyxin E against Gram-negative bacteria and daptomycin against Gram-positive bacteria, and can be used in the antibacterial treatment of pathogens that are insensitive to polymyxins. #imgabs0#

The invention relates to the technical field of drugs, in particular to multifunctional polymyxin B nanoparticles and preparation and application thereof.The multifunctional nanospheres (HPK) of polymyxin B (PMB) are synthesized by connecting hyaluronic acid and polymyxin B through Schiff base bonds and combining KAFAK, and the multifunctional nanospheres (HPK) serve as candidate drugs for refractory infectious diseases and can release PMB in response to the infected microenvironment, so that the effect of treating the refractory infectious diseases is achieved. The targeted infection site removes bacteria and various inflammatory mediators to reduce cytokine storm, including removal of LPS and active oxygen, and inhibition of macrophage activation. Hyaluronic acid (HA) serves as a carrier of PMB, the HA and the PMB are tightly connected through a pH sensitive bond Schiff base bond, the hyaluronic acid can change the biological distribution condition of the PMB, and a targeted CD44 receptor, hyaluronidase and the Schiff base bond can achieve PMB acidic microenvironment targeted delivery and meanwhile cooperate with PMB to resist bacteria and KAFAK to resist inflammation. The design and preparation of HPK effectively achieve the effects of reducing toxicity and enhancing efficacy on PMB.

The invention provides a beta-diketoamide compound and application thereof in preparation of a gram infection resistant drug, the structural formula of the beta-diketoamide compound is as shown in formula (1), in the formula (1), R1 is H or halogen; r2 is nitro, alkyl, halogen or methoxyl. The beta-diketoamide compound disclosed by the invention comprises gram-positive bacteria such as staphylococcus aureus, enterococcus faecalis, enterococcus faecium and staphylococcus epidermidis and other clinical isolates, and shows antibacterial activity; after being combined with polymyxin, the compound has synergistic bacteriostatic activity on gram-negative bacteria such as acinetobacter baumannii, klebsiella pneumoniae, escherichia coli and pseudomonas aeruginosa, and can remove biofilms formed by staphylococcus aureus and enterococcus faecalis.

The invention discloses application of polymyxin B in control of various weeds, and belongs to the technical field of agricultural biology. On one hand, polymyxin B can effectively inhibit growth of roots of various weeds; on the other hand, the plant leaves can be whitened or withered by spraying the fertilizer on the leaves. Experiments show that the root growth inhibition effect of weeds such as arabidopsis thaliana and barnyard grass is enhanced along with increase of the concentration of the polymyxin B, when the concentration of the polymyxin B in a plant culture medium is 10 [mu] M, the arabidopsis thaliana has a stress phenomenon, and when the concentration of the polymyxin B is increased to 50 [mu] M, leaves of the arabidopsis thaliana have a whitening phenomenon and plants die. If a leaf spraying mode is adopted, spraying of polymyxin B with the concentration of 500 [mu] M can make barnyard grass leaves whitened, and alfalfa leaves can be damaged. And through experiments, polymyxin B can whiten various weeds such as ryegrass and amaranthus retroflexus, and the scheme has high efficiency and environmental friendliness.

This invention provides a compound drug for treating melioidosis, its preparation method, and its application. The drug comprises active components of traditional Chinese medicine, a bioactive preparation, and a pharmaceutically acceptable carrier. The active components of traditional Chinese medicine are primarily extracts of Scutellaria baicalensis, Coptis chinensis, Fagopyrum dibotrys, and Polygonum cuspidatum. The bioactive preparation includes polymyxin B, homoserine lactonease, and recombinant human β-defensin 3. The components work synergistically to construct a comprehensive intervention system covering all pathological stages, including biofilm disruption, sterilization, anti-endotoxin activity, intracellular bacterial clearance, immune regulation, and tissue repair. This system can effectively disrupt bacterial biofilms, kill multidrug-resistant strains, neutralize endotoxins, and eliminate latent intracellular bacteria, addressing the core pain points of existing melioidosis treatments, such as strong drug resistance, significant toxic side effects, and high recurrence rates. The preparation process of this invention is carried out under low-temperature and sterile conditions throughout, which fully preserves the stability of the active ingredients, making it suitable for industrial production. The drug can be prepared in various dosage forms, covering all clinical subtypes of melioidosis, and possesses clinical application value and promising prospects for widespread application.

The invention belongs to the technical field of biological medicine, and discloses application of ebb-selenium as a polymyxin synergist in inhibition of salmonella. According to the application, the combination of ebb selenium and polymyxin has a good synergistic effect on salmonella in vitro and in vivo experiments. In a mouse salmonella infection model, compared with the bacterium carrying amount after single-drug treatment, the bacterium carrying amount in the animal liver after EBS and polymyxin combined treatment has the effect that the bacterium carrying amount in the animal liver is obviously reduced. The survival rate of animals treated by the combination of the EBS and the polymyxin is obviously increased compared with the survival rate of the animals treated by single medicines of the EBS and the polymyxin. Compared with the traditional method for killing salmonella through combination of antibiotics, the method has the advantages that the generation of bacterial drug resistance is not easily induced through the synergistic sterilization of the ebb-selenium and the polymyxin, and the ebb-selenium has the characteristics of wide source, multiple effects and good treatment effect, and has better research and application significance for excavating the synergistic replacement of the antibiotics and solving the bacterial drug resistance.

This invention relates to a polymyxin Bacillus strain ( Paenibacillus polymyxa This invention relates to B01 and its applications, belonging to the field of microbial technology. The *Bacillus polymyxa* B01 strain disclosed in this invention has been deposited at the Guangdong Provincial Microbial Culture Collection Center, with accession number GDMCC NO.66594. This strain was isolated, purified, and screened from soil samples. Experiments show that this strain has excellent pH and high-temperature tolerance, and the antibacterial active substances produced by its fermentation have good antibacterial effects against *Escherichia coli*, *Pseudomonas aeruginosa*, *Pseudomonas putida*, *Staphylococcus aureus*, *Candida albicans*, *Aspergillus brasiliensis*, *Propionibacterium acnes*, and *Malassezia*. Furthermore, the antibacterial active substances exhibit excellent heat resistance, cold resistance, light stability, pH stability, and preservative effects. It is a mild and low-irritant raw material that can be used to prepare daily chemical products and pharmaceuticals, possessing broad application prospects and significant value for transformational research.

The invention discloses an antibacterial peptide, a pharmaceutical composition and application, and belongs to the field of polypeptide medicines.The antibacterial peptide forms a novel annular conformation by introducing n-leucine and 2-aminobutyric acid to construct a parent nucleus structure. The affinity of the antibacterial peptide to the main component phosphatidylglycerol of a bacterial cell membrane is remarkably improved, is improved by 31 times or more compared with polymyxin B and is improved by 16 times or more compared with D50 peptide, and the selectivity of the antibacterial peptide to the main component phosphatidylcholine of a mammalian cell membrane is improved by hundreds of times or more compared with that of a control peptide. The polymyxin B peptide has extremely low toxicity to HK-2 kidney cells, and the biological safety of the polymyxin B peptide is obviously superior to that of polymyxin B and D50 peptide. The minimum inhibitory concentration of the antibacterial peptide to gram-negative bacteria is as low as 0.03 mu g / mL, is about 33 times higher than that of polymyxin B, and is 17-33 times higher than that of D50 peptide. The treatment effect of the antibacterial peptide is obviously superior to that of polymyxin B and D50 peptide in various infection models, and the antibacterial peptide is expected to be developed into a novel anti-infection drug and is used for preventing and treating various infections.

Disclosed is use of a combined compound medicine in treating pathogenic bacteria persistent infection. Existing antibiotic monotherapy or combination therapy is usually difficult to kill pathogenic bacteria in the persister state, especially nutrient-insensitive persister bacteria, which often lead to a series of problems of long treatment period, frequent condition recurrence and deterioration, treatment failure, drug-resistant mutation, etc. At present, drugs capable of efficiently killing highly persistent pathogenic bacteria in a clinically applicable concentration range are still unavailable. The novel compound medicine of polymyxin and aminoglycoside antibiotics disclosed in the present disclosure without precedence is capable of destroying bacterial cell membranes in a short time within a relatively wide range of clinically achievable plasma concentrations, leading to rapid death of a large number of bacteria, but is safe for human-derived cells. Therefore, the compound medicine is expected to be applied to the clinical treatment of various acute or chronic infectious diseases caused by pathogenic bacteria in the persister state, shortening the treatment course, preventing the recurrence of infection recurrence, and slowing down the emergence of drug-resistant mutations.

The present application provides a polymyxin prodrug compound with the structure shown in formula (I) or a stereoisomer or a pharmaceutically acceptable salt thereof. The polymyxin prodrug compound of the present application can effectively reduce the biological toxicity of polymyxin, selectively activate in bacterial infected tissues, achieve bacterial killing in infected sites, improve the bioavailability of polymyxin, achieve sustainable development and utilization of classic antibiotics, expand the scope of future clinical application of polymyxin, and has a broad clinical application prospect.

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.

A novel 10 peptide capable of inhibiting the growth of bacteria that are resistant to existing polymyxin, a pharmaceutical composition comprising the novel 10 peptide, and an application thereof in the treatment or prevention of bacterial infections.

The present invention discloses the application of valnemulin in combination with polymyxin in the preparation of a bactericide. The present invention synergistically kills bacteria through valnemulin and polymyxin, and can effectively restore the antibacterial activity of polymyxin against polymyxin-resistant and -sensitive Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae, and Acinetobacter pittii in vitro and in vivo. In addition, valnemulin has no cytotoxicity to mammalian cells, and the application of valnemulin effectively reduces the treatment dose of polymyxin and reduces the risk of side effects of polymyxin on mammals.

The application provides a polymyxin B-loaded nano preparation and a preparation method and application thereof, and belongs to the field of biological nanotechnology.The method comprises the following steps: (1) preparing a water-in-oil emulsion: mixing a water solution of polymyxin B and a dichloromethane solution of polylactic acid-glycolic acid copolymer to obtain a water-in-oil emulsion; (2) preparing an ethanol aqueous solution of hyaluronic acid; (3) mixing the water-in-oil emulsion and the ethanol aqueous solution of hyaluronic acid, and stirring to obtain a nano dispersion; (4) vacuum rotary evaporation of the nano dispersion, collection of a colloidal dispersion, and dispersion of the colloidal dispersion in water to obtain a nano particle solution.The nano preparation prepared by the application does not need a chemical crosslinking agent, and thus effectively avoids problems caused by the introduction of chemical crosslinking.The preparation process is simple and easy to control, has good safety, has good biocompatibility, and provides a basis for the approval of clinical trials and industrial development of atomization drug delivery of antibiotics.

This application discloses a fluorescent probe for labeling the outer membrane of Gram-negative bacteria, its preparation method, and its application. The fluorescent probe uses polymyxin (with its hydrophobic tail and two amino acid residue pairs removed) as a targeting group specifically targeting the outer membrane of Gram-negative bacteria. This structure can specifically bind to the lipopolysaccharide structure in the outer membrane, and is then linked to the fluorophore rhodamine, which has switching properties, to design and synthesize a fluorescent dye. This fluorescent probe, possessing fluorescent switching properties, can be applied to super-resolution imaging of the outer membrane of Gram-negative bacteria.

The invention discloses an antibacterial peptide, a pharmaceutical composition and application, and belongs to the field of polypeptide medicines.The antibacterial peptide forms a novel annular conformation by introducing n-leucine and 2-aminobutyric acid to construct a parent nucleus structure. The affinity of the antibacterial peptide to the main component phosphatidylglycerol of a bacterial cell membrane is remarkably improved, is improved by 31 times or more compared with polymyxin B and is improved by 16 times or more compared with D50 peptide, and the selectivity of the antibacterial peptide to the main component phosphatidylcholine of a mammalian cell membrane is improved by hundreds of times or more compared with that of a control peptide. The polymyxin B peptide has extremely low toxicity to HK-2 kidney cells, and the biological safety of the polymyxin B peptide is obviously superior to that of polymyxin B and D50 peptide. The minimum inhibitory concentration of the antibacterial peptide to gram-negative bacteria is as low as 0.03 mu g / mL, is about 33 times higher than that of polymyxin B, and is 17-33 times higher than that of D50 peptide. The treatment effect of the antibacterial peptide is obviously superior to that of polymyxin B and D50 peptide in various infection models, and the antibacterial peptide is expected to be developed into a novel anti-infection drug and is used for preventing and treating various infections.

The application belongs to the field of genetic engineering and medical engineering, and discloses virK Application of gene in regulation of Klebsiella pneumoniae virulence. The application finds that the expression level of the gene is significantly increased in polymyxin-resistant mutant strains through transcriptome analysis, virK Further research shows that the expression of the gene is regulated by the PhoP / PhoQ two-component regulatory system. The application constructs virK Gene deletion mutant strains and complementary strains, and compares the virulence difference of the strains in an animal infection model, finds that virK The virulence of the deletion strain is significantly reduced, and the complementary strain can restore the virulence phenotype, indicating that virK The gene plays an important role in the regulation of Klebsiella pneumoniae virulence. The application first finds that PhoP can regulate virK Gene expression, and affects the virulence phenotype of Klebsiella pneumoniae through the regulation pathway, thereby revealing a new virulence regulation mechanism, and providing a theoretical basis for subsequent targeted intervention.