Application of small molecule antibacterial peptide from lactobacillus reuteri and tandem repeat derived peptide thereof

Abstract

The present application relates to antibacterial active peptide technology, aiming to provide a kind of Lactobacillus reuteri Small molecule antibacterial peptide and its tandem repeat derivative peptide application.The present application provides the small molecule antibacterial peptide X507 with amino acid sequence as shown in SEQ ID NO.1 and antibacterial peptide X507-4 as shown in SEQ ID NO.2;The latter is the derivative prepared by repeating tandem based on the amino acid sequence of antibacterial peptide X507, which consists of 12 amino acids.The antibacterial peptide and derivative peptide provided by the present application have less amino acids, simple synthesis, low cost, easy industrialization and application;Gram-negative bacteria, gram-positive bacteria and corresponding drug-resistant bacteria growth have broad-spectrum antibacterial activity, good stability, no obvious cytotoxicity advantage, for solving the problem of drug-resistant bacteria infection, promoting green medical treatment and the development of breeding has important significance.

Description

Technical Field

[0001] This invention belongs to the field of antimicrobial active peptide technology, specifically relating to an antimicrobial tripeptide derived from natural lactic acid bacteria, its sequence tandem repeat optimized derivative, and its applications. Background Technology

[0002] Antibiotic resistance has become a major challenge in global public health. Resistant strains of pathogenic bacteria, including Gram-positive and Gram-negative bacteria, continue to emerge, seriously threatening human health and the safety of livestock farming. With the widespread use and even abuse of antibiotics in medical and aquaculture fields, the spread and diffusion of resistant strains have further intensified, making the development of novel, highly effective, and less likely to induce resistance antimicrobial agents particularly urgent.

[0003] Antimicrobial peptides, as an important component of the innate immune defense system, possess advantages such as small molecular weight, broad antimicrobial spectrum, unique antimicrobial action through bacterial cell membrane disruption, and low likelihood of inducing drug resistance, making them an important research direction for antibiotic alternatives. However, existing antimicrobial peptides still have many shortcomings: some natural antimicrobial peptides have low antimicrobial activity, making it difficult to meet practical application needs; some artificially designed antimicrobial peptides have complex structures, leading to high synthesis costs; and some antimicrobial peptides have problems such as high cytotoxicity and poor in vivo safety. In addition, some artificially designed antimicrobial peptides exhibit significant differences in efficacy between in vitro and in vivo. Many antimicrobial peptides that perform well in in vitro screening show low bioavailability after entering the body, resulting in actual in vivo antimicrobial activity far below expectations, failing to effectively clear infections and severely limiting their clinical translation potential.

[0004] Therefore, developing a novel antimicrobial peptide with high activity, good safety, simple preparation, and broad-spectrum antibacterial activity is of great significance for addressing the problem of drug-resistant bacterial infections and promoting the development of green medicine and aquaculture. Summary of the Invention

[0005] This invention aims to address the problem of microbial resistance caused by antibiotic overuse in existing technologies, as well as the common problems of low bactericidal activity, limited performance, and restricted application scenarios of natural antimicrobial peptides. To this end, it provides a small molecule antimicrobial peptide, its sequence-optimized derivatives, and their applications. This antimicrobial peptide has the advantages of broad-spectrum antimicrobial activity, high safety, and controllable synthesis costs, and can serve as a novel antibiotic alternative for antimicrobial applications in multiple fields.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] In a first aspect, the present invention provides a small molecule antimicrobial peptide X507 derived from Lactobacillus reuteri, wherein the antimicrobial peptide X507 is composed of 3 amino acids, the amino acid sequence of which is shown in SEQ ID NO.1.

[0008] Secondly, the present invention also provides a small molecule antimicrobial peptide X507-4 derived from Lactobacillus reuteri, which is a derivative obtained by repeating and tandemly constructing the amino acid sequence of antimicrobial peptide X507; the antimicrobial peptide X507-4 is composed of 12 amino acids, and its amino acid sequence is shown in SEQ ID NO.2.

[0009] Thirdly, the present invention also provides the application of antimicrobial peptide X507 or antimicrobial peptide X507-4 in the preparation of antimicrobial products.

[0010] Preferably, the antibacterial product is an anti-infective drug, feed additive, or daily chemical antibacterial product.

[0011] Preferably, the antibacterial product is used to inhibit the growth of Gram-positive bacteria, Gram-negative bacteria, and corresponding drug-resistant bacteria; the Gram-positive bacteria include Staphylococcus aureus and Listeria monocytogenes; the Gram-negative bacteria include Salmonella typhimurium, Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae.

[0012] Preferably, the dosage form of the antibacterial product is any one of spray, aerosol, gargle, ointment, film, effervescent, drinking water, powder or granule.

[0013] Preferably, the effective concentration of the antimicrobial product against the target pathogen is: based on the minimum inhibitory concentration, antimicrobial peptide X507 is no higher than 512 μg / mL, and antimicrobial peptide X507-4 is no higher than 128 μg / mL; the specific dosage is adjusted according to the dosage form, application scenario and type of target pathogen.

[0014] Fourthly, the present invention also provides an antibacterial product, wherein the product has antimicrobial peptide X507 as the main active ingredient, or antimicrobial peptide X507-4 as the main active ingredient, or a mixture of the above two as the main active ingredient.

[0015] Preferably, the antimicrobial product further comprises a carrier or excipient that is pharmaceutically, feed-wise, or in the daily chemical industry; the carrier or excipient is selected from at least one of buffers, antioxidants, preservatives, carbohydrates, chelating agents, tension modifiers, surfactants, fillers, or binders.

[0016] Compared with the prior art, the technical advantages of the present invention are:

[0017] 1. The antimicrobial peptides and derived peptides provided by this invention have a small number of amino acids, are simple to synthesize, and are inexpensive, making them easy to industrialize and promote.

[0018] 2. The antimicrobial peptides and derived peptides of the present invention have the advantages of broad-spectrum antimicrobial activity against Gram-negative bacteria, Gram-positive bacteria and corresponding drug-resistant bacteria, good stability and no obvious cytotoxicity, which is of great significance for solving the problem of drug-resistant bacterial infection and promoting the development of green medicine and aquaculture. Attached Figure Description

[0019] Figure 1 This is a secondary structure diagram of the derived peptide X507-4 in Example 2 of the present invention.

[0020] Figure 2 This is a mouse survival curve of mice infected with Salmonella typhimurium, based on the antimicrobial peptide X507 derived from Lactobacillus reuteri and its derivative peptide X507-4, in Example 6 of the present invention.

[0021] Figure 3 The image shows the bacterial load results of Lactobacillus reuteri-derived antimicrobial peptide X507 and its derivative peptide X507-4 on the spleen, liver, ileum and cecum contents of mice infected with Salmonella typhimurium in Example 6 of this invention.

[0022] Figure 4 This is a graph showing the effect of antimicrobial peptide X507 and its derivative peptide X507-4 on the serum alanine aminotransferase level in mice in Example 7 of the present invention.

[0023] Figure 5 This is a graph showing the effect of antimicrobial peptide X507 and its derivative peptide X507-4 on serum urea nitrogen levels in mice in Example 7 of the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0025] Example 1: Sources and properties of antimicrobial peptides

[0026] Lactobacillus reuteri was isolated from the intestines of healthy piglets in a pig farm in Zhejiang Province. After fermentation, the supernatant was separated, and then ultrafiltration fractionation (3 kDa cutoff) yielded the small molecule antimicrobial peptide X507. LC-MS / MS identification showed that the antimicrobial peptide consists of three amino acid residues with the amino acid sequence SKL (as shown in SEQ ID NO. 1). The average molecular weight of the antimicrobial peptide is 346.42 Da, the isoelectric point (PI) is 10.09, and the average hydrophilicity coefficient is -0.30. Sequence analysis showed that it is composed of hydrophilic serine (S), positively charged lysine (K), and hydrophobic leucine (L), exhibiting hydrophilic, cationic, and hydrophobic properties, characteristic of typical amphiphilicity. The sequence and physicochemical properties of antimicrobial peptide X507 are shown in Table 1. This invention uses this natural short peptide X507 as the parent peptide for subsequent molecular design and optimization.

[0027] Example 2: Design optimization and structural characterization of antimicrobial peptides

[0028] Using the amino acid sequence SKL of the antimicrobial peptide X507 as the core sequence, a dodecapeptide derivative X507-4 was obtained through four tandem repeats and solid-phase synthesis. Its amino acid sequence is SKLSKLSKLSKL, corresponding to SEQ ID NO.2. X507-4 has an average molecular weight of 1331.66 Da, an isoelectric point (PI) of 10.48, and an average hydrophilicity coefficient of -0.30.

[0029] The sequences and physicochemical properties of the antimicrobial peptide X507 and its optimized derivative X507-4 are shown in Table 1. Compared with the parent peptide X507, X507-4 retains the core physicochemical characteristics (PI>10 indicating cationicity, average hydrophilicity coefficient of -0.30 indicating hydrophilicity), while laying the foundation for its secondary structure formation through the repeated tandem of active units (SKLs). Secondary structure analysis shows that X507-4 can form a typical antimicrobial peptide structure—an α-helix structure—in solution, such as... Figure 1 As shown, this α-helix structure provides a stable spatial conformation for the amphiphilicity of the antimicrobial peptide, allowing the hydrophobic end to effectively insert into the lipid layer of the bacterial cell membrane and the hydrophilic cationic end to bind to the negatively charged groups of the bacterial membrane, thereby significantly enhancing antimicrobial activity. In contrast, the parent peptide X507 is too short to form a stable secondary structure. The above results indicate that a simple four-times tandem repeat strategy not only preserves the core physicochemical properties of the parent peptide but also successfully constructs a dodecapeptide X507-4 with an α-helix structure, providing a structural basis for its significantly enhanced antimicrobial activity.

[0030] Table 1. Sequences and physicochemical properties of antimicrobial peptides

[0031]

[0032] Example 3: Determination of the antimicrobial activity of antimicrobial peptides

[0033] The two antimicrobial peptides shown in SEQ ID NO.1 and SEQ ID NO.2 were synthesized by Sangon Biotech (Shanghai) Co., Ltd. in a solid phase chemical process, and antimicrobial peptide samples with a purity greater than 95% were obtained.

[0034] The antimicrobial effect of antimicrobial peptides was determined using the micro-broth dilution method. The specific steps are as follows:

[0035] (1) Resuscitate the following standard strains: Salmonella Typhimurium ATCC14028, Staphylococcus aureus ATCC25923, Escherichia coli ATCC25922, Listeria monocytogenes ATCC19115, Acinetobacter baumannii ATCC19606, Klebsiella pneumoniae CMCC46117, Pseudomonas aeruginosa ATCC27853; and the multidrug-resistant strains corresponding to the standard strains: Salmonella Typhimurium SSH006, Staphylococcus aureus N315, Escherichia coli MY0201, Listeria monocytogenes L0026, Acinetobacter baumannii B27981, Klebsiella pneumoniae ATCC BAA-1705, and Pseudomonas aeruginosa MJF02-2. All strains were streaked onto LB agar plates and incubated at 37°C for 16 hours. Single colonies were picked and transferred to shake tubes containing 5 mL of LB medium. After incubation at 37°C for 16 hours, the culture was diluted to 10⁻¹⁰ with LB liquid medium. 6 CFU / mL.

[0036] (2) The assay was performed using a 96-well plate with three parallel controls. The antimicrobial peptide was diluted to the highest concentration to be measured using LB medium. Different concentrations of antimicrobial peptide solutions were obtained using a two-fold microdilution method. 50 μL of each solution was added to the wells of the plate, followed by 50 μL of the prepared bacterial culture. For the control without antimicrobial peptide, 50 μL of LB medium and 50 μL of bacterial culture were added. For the blank control, 100 μL of LB medium was added. The plates were incubated at 37°C for 18 hours. After incubation, the OD of each well was measured using a multi-mode microplate reader. 600 The concentration at which an antimicrobial peptide significantly inhibits microbial growth is its minimum inhibitory concentration (MIC).

[0037] The minimum inhibitory concentrations (MICs) of the two antimicrobial peptides shown in SEQ ID NO. 1-2 against various standard strains and multidrug-resistant strains are shown in Tables 2 and 3. The results indicate that both antimicrobial peptides exhibit broad-spectrum inhibitory activity against both Gram-positive and Gram-negative standard strains, while maintaining highly effective antimicrobial activity against corresponding multidrug-resistant strains without cross-resistance, fully demonstrating the inhibitory effect of the antimicrobial peptides of this invention against drug-resistant bacteria.

[0038] In the field of antimicrobial drug development, the MIC value is a core parameter for evaluating the antimicrobial activity of compounds. It is generally believed that when the MIC value is higher than 256 μg / mL, the compound's in vitro antimicrobial activity is weak and often lacks practical application value for further development. In this invention, the MIC values ​​for all tested strains were no higher than 256 μg / mL, meeting the conventional criteria for determining effective in vitro antimicrobial activity in this field. Notably, the derived peptide X507-4 exhibits significantly enhanced activity compared to the parent peptide X507 (for example, against Acinetobacter baumannii resistant strains, the MIC of X507-4 is 8 μg / mL, while that of X507 is 128 μg / mL, representing a 16-fold increase in activity; against Salmonella typhimurium resistant strains, the MIC of X507-4 is 8 μg / mL, while that of X507 is 128 μg / mL, also representing a 16-fold increase in activity). The MIC values ​​against various clinically multidrug-resistant strains are as low as 8–32 μg / mL, and are comparable to the antimicrobial activity of the corresponding standard strains. This indicates that the present invention has successfully obtained a derivative peptide with significantly enhanced antibacterial activity through tandem repeat design, and has better application potential.

[0039] Table 2. Minimum inhibitory concentrations (μg / mL) of antimicrobial peptides against standard strains.

[0040]

[0041] Table 3. Minimum inhibitory concentrations (μg / mL) of antimicrobial peptides against multidrug-resistant strains.

[0042]

[0043] Example 4: Determination of hemolytic activity of antimicrobial peptides

[0044] Blood was collected from the orbital region of C57BL / 6J mice into blood collection tubes containing heparin sodium anticoagulant. The blood was centrifuged at 500×g for 10 minutes at 4°C, and the supernatant was discarded. The cells were washed three times with physiological saline, and the supernatant was discarded again to obtain a 100% red blood cell solution. This solution was then diluted with physiological saline to obtain the 2% red blood cell solution used in the experiment. Antimicrobial peptide diluents of 8, 16, 32, 64, and 128 μg / mL were prepared. 100 μL of red blood cell suspension and 100 μL of antimicrobial peptide diluent were added to each well of a 96-well microplate. The negative control consisted of 100 μL of red blood cell suspension and 100 μL of PBS buffer, while the positive control consisted of 100 μL of red blood cell suspension and 100 μL of 2% Triton X-100 solution. The plates were incubated at 37°C for 1 hour. After incubation, the absorbance was measured at 540 nm using a microplate reader, and the hemolysis rate was calculated. Hemolysis rate (%) = (Sample-PBS) / (TritonX-100-PBS) × 100%; Sample: absorbance of mixtures of antimicrobial peptides and red blood cells at different concentrations; PBS: absorbance of negative control; TritonX-100: absorbance of positive control.

[0045] The results are shown in Table 4. Both antimicrobial peptides represented by SEQ ID NO.1-2 exhibit low hemolytic activity. They demonstrate high safety to host cells, reducing side effects and making them suitable for in vivo application, thus showing greater potential in drug development.

[0046] Table 4. Hemolysis rate of antimicrobial peptides (%)

[0047]

[0048] Example 5: Assay for the cytotoxicity of antimicrobial peptides

[0049] RAW264.7 cells in logarithmic growth phase were harvested, digested with 0.25% trypsin, and the cell suspension was collected in sterile centrifuge tubes. The cells were then resuspended in DMEM complete medium containing 10% fetal bovine serum and the cell density was adjusted to 6 × 10⁶ cells / mL. 4 Cells were seeded at 100 μL / well in 96-well plates and incubated overnight at 37°C in a cell culture incubator containing 5% CO2 to allow cell adhesion. After discarding the old culture medium in the wells, 100 μL / well of fresh DMEM complete medium containing different concentrations of antimicrobial peptide X507 or X507-4 (1.56–200 μg / mL) was added to the experimental group, while fresh DMEM complete medium without antimicrobial peptide was added to the control group (negative control). Each group had 3 parallel wells. After culturing the 96-well plates in the incubator for another 24 hours, 10 μL of CCK8 reagent was added to each well and incubated in the dark for 2 hours. The absorbance (OD value) at 450 nm was measured using a microplate reader. The toxicity of the antimicrobial peptide to RAW264.7 cells was evaluated using the formula "Cell viability (%) = (OD value of experimental group / OD value of negative control group) × 100%".

[0050] The results are shown in Table 5. Both antimicrobial peptides represented by SEQ ID NO.1-2 exhibited low cytotoxicity. The low cytotoxicity of antimicrobial peptides offers advantages such as high drug safety, promotion of wound healing, and facilitating the development of novel therapies.

[0051] Table 5. Cell survival rate of antimicrobial peptides (%)

[0052]

[0053] Example 6: Evaluation of the in vivo therapeutic effect of antimicrobial peptides

[0054] Forty-eight healthy 6-week-old female C57BL / 6 mice were purchased from Shanghai Silex Laboratory Animal Co., Ltd. Eighteen mice were used for in vivo experiments to detect bacterial load in tissues and organs, while the remaining 30 were used to observe survival and growth. All mice were grouped and fed under the same conditions. Mice were weighed individually and randomly divided into three groups (n=16 per group) with no significant individual differences in weight. Each mouse had an individual ear tag. In each group, 10 mice were used to calculate body weight and survival rate, while the other 6 mice were used to monitor clinical symptoms and obtain tissue samples for subsequent tissue bacterial load testing. All animals were kept in identical environments and conditions. Based on the results of previous dose screening experiments, the optimal therapeutic dose of X507 (50 mg / kg) and X507-4 (25 mg / kg) were used for in vivo efficacy evaluation.

[0055] The groups are as follows: (1) Negative control group (treated with PBS only, without antimicrobial peptide treatment, 10 8 (1) CFU Salmonella Typhimurium SL1344 Salmonella infection group, marked as control group); (2) X507 treatment group and Salmonella infection group (each mouse was intraperitoneally injected with 50 mg / kg dose of X507 and 10 mg / kg dose of ...3) X507 treatment group and Salmonella infection group (each mouse was intraperitoneally injected with 50 mg / kg dose of X507 and 10 mg / kg dose of Salmonella Typhimurium SL1344 Salmonella infection group, marked as control group); (4) X507 treatment group and Salmonella 8 (2) CFU Salmonella Typhimurium SL1344, labeled as X507 group); (3) X507-4 treatment group and Salmonella infection group (each mouse was intraperitoneally injected with 25 mg / kg dose of X507-4 and 10 mg / kg dose of Salmonella infection). 8 CFU Salmonella Typhimurium SL1344, labeled as group X507-4).

[0056] During the experiment, all mice had free access to water and antibiotic-free feed. All experimental protocols used in this study complied with those approved by the Experimental Animal Welfare and Ethics Review Committee of Zhejiang University, and all procedures were conducted in accordance with biosafety protocols.

[0057] Monitor mouse body weight, observe general condition, and record mortality. Plot mouse survival rate curves.

[0058] On day 2 after mice were infected with Salmonella, spleen, liver, ileum, and cecum contents were aseptically collected, weighed, and then ground with pre-cooled PBS (pH 7.4) at 4°C. The samples were then serially diluted, and 10 μL of each sample was taken. 0 10 -1 10 -2 10 -3 and 10 -4Five dilutions were used, with 10 µL of each diluted sample spread onto xylose-lysine-deoxycholic acid (XLD) agar plates containing 20 mg / mL streptomycin sulfate. Each dilution was performed in triplicate. The plates were incubated at 37°C overnight. The colony status was observed and counted (the average of the three replicates was calculated) to detect the detection rate of Salmonella typhimurium SL1344 in the samples and the bacterial load in positive samples.

[0059] Figure 2 Survival curves of antimicrobial peptides X507 and X507-4 against Salmonella typhimurium-infected mice; Figure 3 This image shows the bacterial load in the spleen, liver, ileum, and cecum of mice infected with Salmonella typhimurium, in response to the antimicrobial peptides X507 and X507-4. The experimental results are as follows: Figure 2 As shown, the survival rate of mice treated with both antimicrobial peptides X507 and X507-4 was significantly improved. Figure 3 As shown, tissue and organ bacterial load analysis revealed that the number of Salmonella typhimurium colonies in the liver and spleen of mice treated with X507 and X507-4 was below the detection limit, indicating a significant reduction in bacterial pathogenicity. These experimental results suggest that the X507 and X507-4 treatment regimens have significant clinical application potential as a bacterial infection control strategy.

[0060] Example 7: In vivo safety evaluation of antimicrobial peptides

[0061] To further evaluate the biosafety of antimicrobial peptide X507 and its derivative peptide X507-4 in vivo, particularly its potential effects on the liver and kidneys, this study investigated the liver and kidney function of mice in different treatment groups by detecting the levels of alanine aminotransferase and urea nitrogen in mouse serum.

[0062] Eighteen healthy female C57BL / 6 mice aged 6-8 weeks were used in the experiment and randomly divided into three groups (n=6 per group): (1) PBS negative control group (control group): intraperitoneal injection of an equal volume of sterile PBS; (2) X507 treatment group (X507 group): intraperitoneal injection of X507 antimicrobial peptide dissolved in PBS at a dose of 50 mg / kg (the same as the optimal effective dose in Example 6); (3) X507-4 treatment group (X507-4 group): intraperitoneal injection of X507-4 antimicrobial peptide dissolved in PBS at a dose of 25 mg / kg body weight (the same as the optimal effective dose in Example 6). 24 h after administration, blood was collected from the orbital rim of all mice and whole blood was collected in sterile EP tubes. After standing at room temperature for 30 minutes, the blood was incubated at 4°C and 3000 r·min. -1 Centrifuge for 15 minutes and separate the supernatant serum. Detect serum alanine aminotransferase (ALT) and blood urea nitrogen (BUN) levels using a fully automated biochemical analyzer.

[0063] The results are as follows Figure 4and Figure 5 As shown. Compared with the PBS negative control group, mice treated with X507 or X507-4 had significantly lower serum ALT levels ( ). Figure 4 ) and BUN levels ( Figure 5 There were no significant differences between the two. This indicates that at this dosage, neither X507 nor X507-4 caused significant functional damage to the liver and kidneys of mice, demonstrating good in vivo biocompatibility and low organ toxicity.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and do not constitute a limitation on the content of the present invention. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed in the present invention and all fall within the protection scope of the present invention.

Claims

1. A small molecule antimicrobial peptide X507 derived from Lactobacillus reuteri, characterized in that, The antimicrobial peptide X507 consists of 3 amino acids, and its amino acid sequence is shown in SEQ ID NO.

1.

2. A small molecule antimicrobial peptide X507-4 derived from Lactobacillus reuteri, characterized in that, It is a derivative obtained by repeating and tandemly connecting the amino acid sequence of the antimicrobial peptide X507 as described in claim 1; the antimicrobial peptide X507-4 is composed of 12 amino acids, and its amino acid sequence is shown in SEQ ID NO.

2.

3. The use of the antimicrobial peptide X507 of claim 1 or the antimicrobial peptide X507-4 of claim 2 in the preparation of antimicrobial products.

4. The application according to claim 3, characterized in that, The antibacterial product is an anti-infective drug, feed additive, or daily chemical antibacterial product.

5. The application according to claim 3, characterized in that, The antibacterial product is used to inhibit the growth of Gram-positive bacteria, Gram-negative bacteria, and corresponding drug-resistant bacteria; the Gram-positive bacteria include Staphylococcus aureus and Listeria monocytogenes; the Gram-negative bacteria include Salmonella typhimurium, Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae.

6. The application according to claim 3, characterized in that, The dosage form of the antibacterial product is any one of the following: spray, aerosol, gargle, ointment, film, effervescent tablet, drinking water, powder, or granule.

7. The application according to claim 3, characterized in that, The effective concentration of the antimicrobial product against the target pathogen is as follows: based on the minimum inhibitory concentration, antimicrobial peptide X507 is no higher than 512 μg / mL, and antimicrobial peptide X507-4 is no higher than 128 μg / mL; the specific dosage is adjusted according to the dosage form, application scenario and type of target pathogen.

8. An antibacterial product, characterized in that, The active ingredient is the antimicrobial peptide X507 as described in claim 1, or the antimicrobial peptide X507-4 as described in claim 2, or a mixture of the two as described in claim 2.

9. The product according to claim 8, characterized in that, The antimicrobial product further includes a carrier or excipient that is pharmaceutically, feed-wise, or in the daily chemical industry; the carrier or excipient is selected from at least one of buffers, antioxidants, preservatives, carbohydrates, chelating agents, tension modifiers, surfactants, fillers, or binders.

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