38results about How to "Simple experimental technique" patented technology

The invention provides a derived peptide for a chicken origin antibacterial peptide as well as a preparation method and application thereof. The sequence of the derived peptide is shown as SEQ No.1. The preparation method comprises the following steps: intercepting 20 amino acids of a chicken origin AvBD4 leader peptide, replacing 5th cysteine and 6th, 7th and 12th phenylalanine by amino acid lysine with charges respectively, meanwhile, carrying out amidation on a carboxyl terminal of the antibacterial peptide, and increasing a positive charge to improve the stability of the antibacterial peptide; adopting a solid-phase chemical synthesis method to obtain crude MGW21; and purifying and identifying synthesized polypeptide by using reversed-phase high performance liquid chromatography and electrospray mass spectrometry. The invention provides the application of the antibacterial peptide in preparing a medicament for treating gram-positive bacteria or gram-negative bacteria infectious diseases. The antibacterial peptide is good in amphiphilic property; compared with an antibiotic and Melittin, the antibacterial peptide is high in antibacterial activity and low in cytotoxicity.

The invention provides a preparation method of indium oxide with new appearance, belonging to the technical field of synthesis and nano material of the indium oxide. The preparation method comprises the following steps: taking inorganic salt solution of the indium as an indium source, adopting N, N-dimethyl formamide (DMF) as an alkali source and anion active agents such as sodium dodecyl sulfate (SDS) and the like as an additive, using hydrothermal synthesis to prepare the novel hollow-microspherical and flower-shaped indium oxide with the secondary structure under the condition without adding any hard template, and controlling the appearance of the secondary structure by chemical means. In the preparation method provided by the invention, the technical process is simple, the promotion is easy, the selected reagent is low in price and environment-friendly, and the need on low-cost, large-scale and green production is met.

The invention discloses an internal reference gene and a construction method for PCR (polymerase chain reaction) expression analysis of caucasian clover. A nucleotide sequence of the internal reference gene is as shown in the sequence SEQ ID No.2; the construction method comprises the steps as follows: selecting 7 internal reference genes with stable expression by utilizing 7 tissue transcriptomedata of caucasian clover, and selecting one traditional internal reference gene commonly used in clover as a control; performing primer design on the candidate internal reference genes, performing PCRamplification on each cDNA, and obtaining the amplification efficiency of primers and the cycle number of amplification reaching a threshold value; evaluating and analyzing the obtained data for internal reference stability, and finally screening the most suitable internal reference gene and the number of the internal reference gene under specific experimental conditions. The reference gene is used as a reference for detecting the gene expression level change of caucasian clover, and for correcting the loading quantity of sample and an experimental error existing in a sample loading process,so as to ensure the accuracy of experimental results.

The invention provides a targeted antimicrobial peptide for Gram-negative bacteria, a production method and application thereof. Its sequence is shown in the sequence table SEQ ID No.1. The preparation method uses the R language to statistically analyze the amino acid sequence characteristics of the natural antibacterial peptide library, and for the peptide chains that only have antibacterial activity against Gram-negative bacteria, the peptides that affect the antibacterial activity The chain parameters were statistically analyzed, and the optimal amino acid composition was screened, namely K, G, L; the number of positive charges: 4, and the hydrophobicity: 30%-50%. Insert tryptophan into the center of the screening sequence to design a centrosymmetric short peptide sequence; to obtain a short-chain narrow-spectrum antimicrobial peptide sequence with low toxicity, high efficiency, and less likely to cause immune regulation disorders in the body. The targeted antimicrobial peptide is beneficial to kill harmful bacteria while maintaining micro-ecological balance. The antimicrobial peptide has high activity, strong stability, and relatively low cytotoxicity. It has the potential to replace antibiotics and become a safer and environmentally friendly new antibacterial product. .

The invention provides a high cell-selectivity cyclic antimicrobial peptide OIR3 and a preparation method and application thereof. The high cell-selectivity cyclic antimicrobial peptide OIR3 has a sequence shown in the formula of SEQ ID No. 1 in the sequence table. The preparation method comprises 1) designing a cyclic antimicrobial peptide OIR3 according to a cyclic antimicrobial peptide template (IleArg)nPro(IleArg)n, wherein n is 3, and 2) synthesizing a peptide resin by a solid phase synthesis method using a polypeptide synthesizer, carrying out TFA cutting to obtain a polypeptide, and carrying out reversed-phase high-performance liquid chromatography purification so that the antimicrobial peptide OIR3 is obtained. The antimicrobial peptide can be used in drugs for treating diseases infected by gram-positive bacteria or gram-negative bacteria. The antimicrobial peptide OIR3 is a high cell-selectivity cyclic antimicrobial peptide, has strong antibacterial activity and weak hemolytic activity, has the highest treatment index and has a great development potential.

The invention discloses a targeting antimicrobial peptide and a preparation method and application thereof. A sequence of the targeting antimicrobial peptide cCF10-C4 is shown in a sequence table SEQ ID No.1. The preparation method comprises the steps that enterococcus faecalis serves as a target bacterium to obtain the targeting antimicrobial peptide cCF10-C4 through design, a series of multi-structural-domain antimicrobial peptide molecules having selectivity to the enterococcus faecalis are established in a heterozygous mode. The design of a series of antimicrobial peptide molecules mainly includes two independent functional areas, namely a sterilization area and an identification area respectively. The targeting antimicrobial peptide has targeting selection capability to the target bacterium. The targeting antimicrobial peptide cCF10-C4 is conductive to reestablishment of microecological balance after treatment.

The invention provides an anti-enzymatic antibacterial peptide I9H12 and a preparation method and application thereof. The sequence of antimicrobial peptide I9H12 is shown in SEQ ID No. 1 of the sequence listing. Preparation method: Referring to the properties of amino acids, while avoiding the cleavage sites of major proteases in the body as much as possible, the hydrophobic amino acid isoleucine (Ile) and the positively charged amino acid histidine (His) were selected as the main amino acids to design a new I9H12 antimicrobial peptide , and amidation of the carboxy terminus of the peptide to increase a positive charge and increase the stability of the peptide. Application of the antibacterial peptide in the preparation of targeted antibacterial drugs for treating Gram-negative bacteria or fungal infectious diseases. The invention effectively improves the anti-enzymatic hydrolysis ability of the antibacterial peptide and improves its application potential in actual production.

The present invention provides a derivative peptide W8 based on amphibian frog-derived antimicrobial peptide and its preparation method and application. The sequence of the derivative peptide W8 is shown in SEQ ID No.1. The preparation method is as follows: According to the amphibian frog-derived antimicrobial peptide, the antimicrobial peptide P8 was designed. Its sequence is as follows: AARILRPRFR. As follows: AARIILRWRFR. The application of the derived peptide W8 in the preparation of medicines for treating Gram-negative bacteria, Gram-positive bacteria and fungal infectious diseases. The antibacterial activity of antibacterial peptide W8 is significantly stronger than that of Kunitzin‑RE, and it has a significant broad-spectrum antibacterial activity that Kunitzin‑RE does not possess. W8 improves the selectivity of antimicrobial peptides between bacterial cells and mammalian cells.

The present invention provides a method for designing Escherichia coli targeting antimicrobial peptide KI-QK, the sequence of which is shown in SEQ ID No.1 in the sequence table. A peptide KI with an α-helical structure is used, and peptide QK is connected to its C-terminus. At the same time, three flexible amino acids glycine are used as linkers between KI and QK, and the peptide is named KI-QK. In the biological activity test, we found that KI‑QK has a very strong antibacterial activity against Escherichia coli, and its geometric mean minimum inhibitory concentration against Escherichia coli is 3.667, which is 4.2 times higher than that of the original peptide KI. The index is 69.812, which is 4.7 times higher than that of the original peptide. In summary, KI‑QK is a typical targeting antimicrobial peptide, which has strong targeting effect on Escherichia coli and has high application value.

The invention provides a β-hairpin antibacterial peptide containing asparagine and glycine turn angle and a preparation method. The sequence of the antimicrobial peptide WRFNG of the present invention is shown in SEQ ID No.1. The preparation method of the present invention uses the Asn-Gly corner as the corner unit, forms the mutual attraction of two β-side chains with the interaction of Trp and Arg, and designs the antibacterial peptide template XWYRYZZXWYRY-NH according to the arrangement principle of the β-hairpin structure 2 . X=R, Y=F, ZZ=NG. The application of the antibacterial peptide in the preparation of drugs for treating infectious diseases caused by Gram-positive bacteria and / or Gram-negative bacteria. The therapeutic index of the antimicrobial peptide of the present invention reaches 138.30, which is 1.58 times higher than WRFPG with Pro-Gly corner, and 3.55 times higher than WRFpG with D-Pro-Gly corner, and has the development potential to become a green and efficient antibiotic substitute.

The invention provides AMP (antimicrobial peptide) WW based on a peptide miniaturization strategy as well as a preparation method and an application of the AMP WW. The sequence of the AMP WW is shown as SEQ ID NO.1 in the sequence table. By adopting the peptide miniaturization theory and a bioactivity improving strategy and taking dermaseptin-family peptides secreted by amphibian frog skin as a template, the sequence containing key physical parameters of mother peptides and having the length shortened to 13 amino acids is obtained. The bacteriostatic activity of WW is slightly lower than that of melittin, while the therapeutic index is as high as 69.8 and is 698 times that of the melittin. With adoption of the method, risks of immunogenicity and heterogenous repellency are avoided theoretically, the selectivity of the AMP between bacterial cells and mammalian cells is improved, and the development potential of the AMP for becoming an antibiotic substitute is improved.