9 results about "Melittin" patented technology

The application relates to a high-purity melittin purification method using pH zone refining countercurrent chromatography. In order to overcome the defects of the prior art, a solvent system composed of 4-12% methyl tert-butyl ether, 42-50% n-butanol, 4-12% acetonitrile and 42-50% deionized water is used, a high-purity melittin solution is purified by using the pH zone refining countercurrent chromatography, and the finished high-purity melittin is obtained through concentration and drying. The application does not use solid fillers, does not cause loss to the sample, can almost recover all the melittin in the crude melittin, the yield is more than 90%, and the application is suitable for batch purification of high-purity melittin.

The invention provides a melittin polymer, which is formed by at least connecting disulfide bonds between two melittin variant molecules after a melittin variant is formed by mutating alanine at the fourth site of an amino acid sequence of a melittin monomer into cysteine and mutating isoleucine at the twentieth site into cysteine in the amino acid sequence of the melittin monomer. The preparation method of the melittin polymer comprises the following steps: obtaining a melittin variant through escherichia coli recombinant expression, and purifying and oxidizing the obtained melittin variant through a nickel column to obtain the melittin polymer, and carrying out gel filtration chromatography on the obtained melittin polymer to obtain the purified melittin polymer. The invention also provides an application of the melittin polymer, and the melittin polymer is used for preparing antibacterial drugs or antibacterial feed additives. The prepared melittin polymer can effectively reduce the toxicity to red blood cells, has relatively strong environmental responsiveness and stability, and can effectively prolong the antibacterial aging.

The invention discloses a spore surface display vibrio parahaemolyticus VPOmpK-MeL recombinant bacillus subtilis as well as a construction method and application thereof. According to the recombinant bacillus subtilis, on the basis of an integrated plasmid pDG364, a recombinant vector which takes spore capsid protein CotY as anchoring protein and displays a fusion fragment of a VPOmpK antigen and bee venom peptide Melittin on the surface is constructed, recombinant protein is converted into a wild type bacillus subtilis 168 gene, and the obtained recombinant spore expressing OmpK-MeL protein has genetic stability; the bacterium directly displays antigen protein on the surface of a spore, does not need to be broken, and can be directly mixed with materials or drink water to immunize animals, so that the problems of difficult protein purification, tedious injection immunization process and the like are avoided; the spores have good stress resistance, so that the spores are easy to store and transport, and the cost is remarkably reduced; the strain can induce specific immune response, and the fusion expressed MeL plays an excellent role in enhancing immunity, so that a new way is provided for prevention and treatment of VP, and the strain can be applied to development of commercial vaccines.

一种蜂毒肽改造肽及其应用，涉及生物医药技术领域，本发明的蜂毒肽改造肽Melittin‑m1‑5为基于天然蜂毒肽Melittin进行结构改造获得的，其氨基酸序列为如EQ ID NO:1所示。实验证明，Melittin‑m1‑5在微摩尔浓度范围内细胞毒性显著低于天然蜂毒肽，也能够显著抑制脂多糖诱导的炎症反应，降低炎症因子的表达，并表现出降低的溶血性。本发明提供的蜂毒肽改造肽在降低细胞毒性和溶血性的同时，保持并增强了抗炎活性，具有良好的应用安全性和开发前景，为抗炎相关药物及外用制剂的研发提供新的候选分子。

The present application relates to the technical field of cyclic peptide drug synthesis, and particularly relates to a method for synthesizing mirror image cyclic peptide by using OaAEP1 enzyme with the assistance of thioester, which comprises the following steps: firstly, a linear thioester precursor of mirror image cyclic peptide is synthesized by using an N-fluorenylmethyloxy carbonyl (Fmoc) solid-phase polypeptide synthesis method; and then the thioester precursor can generate the mirror image cyclic peptide under the mediation of OaAEP1 enzyme. The present application first synthesizes mirror image melittin (D-cMelittin) by using OaAEP1 enzyme with the assistance of thioester, and the mirror image melittin has high protease stability and good antibacterial activity.

The application provides a kind of base hornet MP-B peptide site-directed mutation derivative antibacterial peptide and its preparation method and application, belong to biotechnology field, the sequence of antibacterial peptide is as shown in SEQ ID No.1.The application uses base hornet MP-B peptide as template, respectively, the serine of 5, 8 is replaced by threonine, the amino acid sequence formed as shown in SEQ ID No.1, and the C-terminal is acylated with-NH2, is synthesized by solid phase chemistry, and after reversed-phase high performance liquid chromatography purification and mass spectrometry identification, the preparation of the antibacterial peptide is completed, the application of the antibacterial peptide in preparing antibacterial drug for treating gram-negative bacteria and / or gram-positive bacteria and / or fungal infectious diseases is disclosed.The antibacterial peptide of the application has the characteristics of high activity, low toxicity and high stability, and has the application potential of becoming a high-efficiency antibiotic substitute.

The invention belongs to the technical field of biological medicines, and provides a recombinant adeno-associated virus particle containing a targeted transcriptional melittin gene as well as a preparation method and application of the recombinant adeno-associated virus particle. Wherein the expression cassette containing the targeted transcriptional melittin gene contains a human telomerase reverse transcriptase core promoter, a tetracycline response element, an optimized melittin gene, a ribosome insertion sequence and a human enterokinase light chain-melittin fusion gene. The invention aims to solve the problem of how to realize precise targeted therapy of tumors, effectively kill tumor cells, reduce damage to normal cells to the greatest extent, overcome the limitation of a traditional treatment method and solve the problem of packaging cell death caused by advanced transcription of melittin genes in a recombinant AAV packaging process. And it is ensured that melittin expressed in tumor cells has a natural sequence and activity, and a safer and more effective treatment choice is provided for tumor patients.

The invention belongs to the field of biological medicine, and discloses melittin nano-composite temperature-sensitive hydrogel (NCP) and application thereof in prevention of postoperative recurrence of breast cancer, chitosan-based hybrid hydrogel is used as a carrier, and melittin and vitamin E succinic acid polyglutamic acid self-assembled nanoparticles (M / E15) are loaded. The hydrogel can be instantly and locally administered after operation and is used for preventing postoperative recurrence of breast cancer. The NCP has thermosensitivity, injectability and tissue adhesiveness, can fill up a treatment window between operation and chemotherapy, and realizes rapid coverage of postoperative wounds and drug sustained release. By directly killing residual tumor cells, inducing death of immunogenic cells, regulating Th1 / Th2 / Th17 / Treg cell differentiation and promoting M1 type polarization of macrophages, an immunosuppression microenvironment is reversed, so that tumor recurrence is inhibited. Meanwhile, NCP can inhibit release of proinflammatory factors, promote angiogenesis and skin remodeling and accelerate wound healing. In an advanced rupture model, the NCP and the PD-L1 antibody are combined for use, so that the anti-tumor effect can be synergistically enhanced, and wound repair can be promoted.

The present invention relates to a novel synthesis method for iodine-based nanoparticles and, more specifically, to iodine-based nanoparticles manufactured by electron beam irradiation, a method for manufacturing same, and a medical use thereof. Unlike conventional chemical synthesis methods, the method for manufacturing iodine-based nanoparticles, according to the present invention, can rapidly mass-produce small- and uniform-sized nanoparticles with a simple synthesis method using electron beam irradiation, and the iodine-based nanoparticles manufactured thereby are loaded with melittin and conjugated with transferrin, and thus can be used as a contrast agent for diagnostic imaging, as a drug delivery platform targeting a transferrin receptor, and as a therapeutic agent capable of treating vascular diseases by delivering drugs such as melittin.