N-terminal fatty acid modified antibacterial peptide analogue and application thereof

Abstract

The invention provides an antibacterial peptide analogue modified by N-terminal fatty acid and application of the antibacterial peptide analogue. Specifically, the antibacterial peptide analogue is modified by fatty acid (dodecanoic acid, tetradecanoic acid or octadecanoic acid) at the N terminal of ultrashort peptide Lys-Gly-Lys so as to form a lipopeptide substance. The N-terminal fatty acid modified antibacterial peptide analogue can inhibit various pathogenic bacteria, especially various dairy cow mastitis pathogenic bacteria, has efficient inhibitory activity, is unique in antibacterial mechanism, does not easily induce the pathogenic bacteria to generate drug resistance, not only can more safely inhibit bacteria, but also can effectively inhibit the pathogenic bacteria. The problem of antibiotic resistance easily generated in the cow mastitis treatment process can be solved; furthermore, the antibacterial peptide analogue disclosed by the invention can also down-regulate expression of proinflammatory factors (such as TNF-alpha and IL-6) of an organism and accelerate tissue repair of an infected part. The antibacterial peptide analogue disclosed by the invention can effectively improve the cure rate of dairy cows and reduce the economic loss.

Description

Technical Field

[0001] The present invention relates to the technical field of biochemistry, and in particular to an N-terminal fatty acid-modified antimicrobial peptide analogue and use thereof. Background Art

[0002] Currently, clinical treatment for bovine mastitis primarily relies on antibiotics, such as penicillins and cephalosporins. However, the long-term and widespread use of antibiotics has led to numerous problems. For one thing, increasing pathogen resistance has reduced the effectiveness of antibiotic treatment. Extensive antibiotic use, coupled with the development of drug residues and the increased resistance of pathogenic microorganisms, poses a serious threat to food safety, leading to growing consumer concerns about the quality and safety of dairy products. Therefore, the development of novel, safe, and effective treatments for bovine mastitis is urgently needed.

[0003] Antimicrobial peptides, due to their unique chemical structures, exhibit excellent antibacterial, antiviral, and immunomodulatory activities, attracting widespread attention for their potential applications in the medical field. However, antimicrobial peptides with different structures exhibit significant differences in activity and safety. Therefore, screening for safe and reliable antimicrobial peptides that are highly effective in treating bovine mastitis is of great practical significance. Summary of the Invention

[0004] In order to solve the problems of the prior art, the present invention provides an N-terminal fatty acid-modified antimicrobial peptide analog. Specifically, the antimicrobial peptide analog of the present invention has a fatty acid modification at the N-terminus of the ultrashort peptide Lys-Gly-Lys to form a lipopeptide substance (for example, C12-KGK, C14-KGK, C16-KGK and C18-KGK). For example, the structure of C18-KGK is a fatty acid chain (C18) connected to L-lysine (Lys, K) and L-glycine (Gly, G) through an amide bond to form C18-KGK, and an amide end-capping is performed at the C-terminus of the short peptide chain, which is represented by C18-Lys-Gly-Lys-NH2, and the chemical formula is C 32 H 64 N6O4, molecular structure is as follows Figure 1 shown.

[0005] The present invention discovers for the first time that lipopeptides obtained by modifying the N-terminus of the ultrashort peptide Lys-Gly-Lys with a fatty acid can effectively inhibit bacteria, particularly those that cause bovine mastitis. Therefore, in another aspect, the present invention also provides uses of the N-terminally fatty acid-modified antimicrobial peptide analogs of the present invention, particularly in the preparation of antimicrobial drugs / preparations or in the preparation of drugs / preparations for treating mastitis (e.g., bovine mastitis).

[0006] Furthermore, the N-terminally fatty acid-modified antimicrobial peptide analogs described herein offer promise and opportunities as novel antimicrobial agents for combating drug-resistant bacteria. Numerous studies have demonstrated that positive charge and hydrophobicity are essential for the biological activity and primary mechanism of action of antimicrobial peptides. The positive charge promotes electrostatic interactions between the antimicrobial peptide and the negatively charged bacterial membrane, while the hydrophobicity facilitates insertion of the antimicrobial peptide into the bacterial membrane bilayer, causing membrane disruption and permeability, ultimately leading to bacterial leakage and bacterial death.

[0007] In this regard, the technical solutions of the present invention include but are not limited to the following:

[0008] In one aspect, the present invention provides an N-terminal fatty acid-modified antimicrobial peptide analog, the structural formula of which is: Cn-Lys-Gly-Lys-NH2, wherein Cn is a fatty acid linked to the α-amino group of the N-terminal lysine, and the fatty acid is selected from dodecanoic acid (i.e., CH3-(CH2)9-CH2-COOH), tetradecanoic acid (i.e., CH3-(CH2)9-CH2-COOH), 11 -CH2-COOH) or octadecanoic acid (i.e., CH3-(CH2) 15 -CH2-COOH).

[0009] In one aspect, the fatty acid of the present invention is selected from dodecanoic acid (ie, CH3-(CH2)9-CH2-COOH) or octadecanoic acid (ie, CH3-(CH2)9-CH2-COOH). 15 -CH2-COOH), preferably, the fatty acid is selected from octadecanoic acid (ie, CH3-(CH2) 15 -CH2-COOH).

[0010] Preferably, in one aspect, the fatty acid of the present invention is octadecanoic acid (ie, CH3-(CH2) 15 -CH2-COOH).

[0011] In one aspect, the present invention provides an N-terminal fatty acid-modified antimicrobial peptide analog, the structural formula of which is: Cn-Lys-Gly-Lys-NH2, wherein Cn is a fatty acid linked to the α-amino group of the N-terminal lysine, and the fatty acid is octadecanoic acid (i.e., CH3-(CH2) 15 -CH2-COOH).

[0012] In one aspect, the present invention provides an N-terminally fatty acid-modified antimicrobial peptide analog, the structural formula of which is:

[0013] In one aspect, the amino acids in the N-terminally fatty acid-modified antimicrobial peptide analogs of the present invention are all natural amino acids.

[0014] In another aspect, the present invention provides use of the N-terminally fatty acid-modified antimicrobial peptide analogue of the present invention in the preparation of antimicrobial drugs / preparations.

[0015] In one aspect, the antibacterial drug / preparation of the present invention is an anti-Gram-positive bacteria drug / preparation or an anti-Gram-negative bacteria drug / preparation.

[0016] In one aspect, the anti-Gram-positive bacteria drug / preparation of the present invention is selected from the group consisting of an anti-Streptococcus agalactiae drug / preparation and an anti-Staphylococcus aureus drug / preparation. Preferably, the anti-Gram-positive bacteria drug / preparation of the present invention is selected from the group consisting of an anti-Streptococcus agalactiae GS032 drug / preparation and an anti-Staphylococcus aureus GS1311 drug / preparation.

[0017] In one aspect, the anti-Gram-positive bacteria drug / preparation of the present invention is an anti-Streptococcus agalactiae drug / preparation. Preferably, the anti-Gram-positive bacteria drug / preparation of the present invention is an anti-Streptococcus agalactiae GS032 drug / preparation.

[0018] In one aspect, the anti-Gram-negative bacteria drug / preparation of the present invention is selected from anti-Escherichia coli drugs / preparations. Preferably, the anti-Gram-negative bacteria drug / preparation of the present invention is anti-Escherichia coli YN001-2 drug / preparation.

[0019] In yet another aspect, the present invention provides use of the N-terminally fatty acid-modified antimicrobial peptide analog of the present invention in the preparation of a medicament / preparation for treating mastitis.

[0020] In one aspect, the mastitis of the present invention is mastitis caused by Streptococcus agalactiae, Staphylococcus aureus or Escherichia coli.

[0021] In one aspect, the mastitis of the present invention is mastitis caused by Streptococcus agalactiae.

[0022] Preferably, the mastitis described in the present invention is mastitis caused by Streptococcus agalactiae GS032.

[0023] In one aspect, the mastitis of the present invention is cow mastitis.

[0024] In one aspect, the mastitis described herein is caused by Streptococcus agalactiae, Staphylococcus aureus, or Escherichia coli. Preferably, the mastitis described herein is caused by Streptococcus agalactiae. More preferably, the mastitis described herein is caused by Streptococcus agalactiae GS032.

[0025] In another aspect, the present invention provides use of the N-terminally fatty acid-modified antimicrobial peptide analog of the present invention in the preparation of a medicament for reducing inflammation in the body, preferably, the inflammation is caused by Streptococcus agalactiae, Staphylococcus aureus or Escherichia coli.

[0026] In one aspect, the inflammation of the present invention is inflammation caused by Streptococcus agalactiae, Staphylococcus aureus or Escherichia coli.

[0027] In one aspect, the inflammation of the present invention is inflammation caused by Streptococcus agalactiae. Preferably, the inflammation of the present invention is inflammation caused by Streptococcus agalactiae GS032.

[0028] In one aspect, the present invention provides for reducing inflammation in the body by reducing the expression of pro-inflammatory factors (eg, TNF-α and / or IL-6) in body tissues.

[0029] In one aspect, the present invention further reduces inflammation in the body by reducing inflammatory cells in body tissues.

[0030] In one aspect, reducing inflammation in the body according to the present invention also manifests itself as promoting the healing or recovery of inflamed tissues in the body.

[0031] Beneficial effects of the present invention:

[0032] In short, the N-terminally fatty acid-modified antimicrobial peptide analogs described herein exhibit highly effective inhibitory activity against a variety of pathogens, particularly those causing bovine mastitis. Their unique antimicrobial mechanism is less likely to induce drug resistance in pathogens, addressing the challenge of antibiotic resistance that can easily develop during the treatment of bovine mastitis. Furthermore, the antimicrobial peptide analogs described herein are naturally derived, biodegradable in animals, and leave no drug residue, ensuring the safety of dairy products. These antimicrobial peptide analogs can effectively improve the cure rate of dairy cows and reduce economic losses.

[0033] Specifically, the present invention successfully constructed an N-terminal fatty acid-modified antimicrobial peptide analog that has both high antimicrobial activity and low risk of drug resistance. Given that the target specificity of traditional antibiotics may lead to the rapid emergence of drug resistance, the multi-target mechanism of antimicrobial peptides makes it more difficult for bacteria to develop drug resistance. The present invention constructs a functional molecule with an amphiphilic structure by precisely coupling hydrophobic alkyl chains (e.g., C12, C14, C16, and C18 alkyl chains) with cationic KGK polypeptide sequences. It exhibits significant advantages in terms of mechanism of action, safety, and application potential. Furthermore, the antimicrobial peptide analog of the present invention not only has antimicrobial function, but also can regulate the expression of host inflammatory factors. The antimicrobial peptide analog of the present invention (e.g., C18-KGK) can not only kill bacteria, but also downregulate the expression of pro-inflammatory factors (e.g., TNF-α, IL-6), accelerating tissue repair at the site of infection. In addition, the antimicrobial peptide analog of the present invention is composed of natural amino acids and fatty acids and is easily decomposed by microorganisms in the environment, while traditional antibiotics are prone to long-term residues in soil and water, inducing the spread of environmental resistance genes. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is the structural formula of C18-KGK.

[0035] Figure 2 This is the mass spectrum of C18-KGK.

[0036] Figure 3 This is the mass spectrum of C12-KGK.

[0037] Figure 4 This is the mass spectrum of C14-KGK.

[0038] Figure 5 This is the mass spectrum of C16-KGK.

[0039] Figure 6 This is the mass spectrum of C18-KK.

[0040] Figure 7 This is the hemolysis rate curve of lipopeptides with different fatty acid chains.

[0041] Figure 8 It is a mouse mastitis model, N group (control group): mice were not treated with any treatment; P group (mastitis group): mouse mastitis model infected with Streptococcus agalactiae GS032, and no treatment was given; KGK group (antimicrobial peptide analog treatment group): mouse mastitis model infected with Streptococcus agalactiae GS032, and the C18-KGK antimicrobial peptide analog was injected through the mammary duct for treatment; Cefotaxime group (cefotaxime treatment group): mouse mastitis model infected with Streptococcus agalactiae GS032, and the antibiotic (cefotaxime) was injected through the mammary duct for treatment.

[0042] Figure 9 The results of HE staining of mouse mammary gland pathological sections.

[0043] Figure 10 Statistical analysis results of the bacterial load detection test in mouse mammary tissue.

[0044] Figure 11 These are the statistical analysis results of the IL-6 and TNF-α factors in the mouse mammary tissue inflammatory factor detection test. Specific implementation plan

[0045] Example 1 Preparation of C18-KGK Antimicrobial Peptide Analogs

[0046] The antimicrobial peptide analogues involved in the present invention were synthesized by Shanghai Qiangyao Biotechnology Co., Ltd. (Shanghai, China) using solid-phase synthesis technology. Specifically, using resin as a solid-phase carrier, according to the Fmoc (9-fluorenylmethoxycarbonyl) amino acid protection strategy, Fmoc-K(Fmoc)-OH, Fmoc-G-OH, and Fmoc-K(Fmoc)-OH amino acids were coupled in sequence, and then the Fmoc protecting group was removed with piperidine, and then a condensation reaction was carried out with C18 fatty acid. Finally, the resin was cleaved with trifluoroacetic acid to obtain a crude product. The crude product was purified by high-performance liquid chromatography (HPLC) to obtain a C18-KGK antimicrobial peptide analogue with a purity greater than 95%. The final product is in the form of a lyophilized powder, wherein the antimicrobial peptide analogue C18-KGK is represented by C18-Lys-Gly-Lys-NH2, and its molecular structure is as follows Figure 1 As shown in the mass spectrum Figure 2 The antimicrobial peptide was prepared into a stock solution with a final concentration of 10 mg / mL using sterile PBS and stored at -80°C until use.

[0047] Example 2 Minimum inhibitory concentration (MIC) of antimicrobial peptide analogs

[0048] C12-KGK, C14-KGK, C16-KGK and C18-KK were synthesized in the same manner as in Example 1. The mass spectra were as follows: Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 , as a control for C18-KGK. Overnight cultures of Streptococcus agalactiae GS032, Staphylococcus aureus GS1311, and Escherichia coli YN001-2 were inoculated into TSB (trypticase soy broth) at a ratio of 1:50 and shaken at 220 rpm until the OD600 reached 0.6-0.8. The cells were collected and diluted in TSB to a concentration of 1×10 5CFU / mL, and the final concentrations of the synthetic lipopeptides were adjusted to 400μg / mL, 200μg / mL, 100μg / mL, 50μg / mL, 25μg / mL, 12.5μg / mL, 6.25μg / mL, 3.12μg / mL, 1.5μg / mL, 0.75μg / mL, 0.37μg / mL, 0.18μg / mL, 0.09μg / mL and 0.045μg / mL by the two-fold dilution method. At the same time, sterile PBS was set up as a positive control group, and 100μL of the prepared bacterial suspension was added to each gradient. The cells were cultured at 37℃ and 220rpm for 12-16h to observe the results.

[0049] In this embodiment, Streptococcus agalactiae GS032, Staphylococcus aureus GS1311, and Escherichia coli YN001-2 were all isolated from milk samples produced by cows with mastitis in the inventor's laboratory and were reported in the inventor's previously published articles. For example, the article "S. agalactiae GS032" (named LZ032 in the article) was disclosed in Peng J et al., Biochem Biophys Res Commun. 2022 Apr 23; 601: 153-159, and the article "S. aureus GS1311" was disclosed in Peng J et al., Int J Antimicrob Agents. 2023 Sep; 62(3): 106916. In addition, the specific isolation methods of Streptococcus agalactiae GS032, Staphylococcus aureus GS1311, and Escherichia coli YN001-2 can be referred to Liu Xuming et al., Animal Husbandry and Veterinary Medicine, 2021, 53(11): 117-122.

[0050] Table 1 MICs of lipopeptides with different fatty acid chains

[0051]

[0052] Example 3 Hemolytic activity of C18-KGK

[0053] Take a clean 1.5mL centrifuge tube, mark it, add 200μL of lipopeptide diluted in sterile PBS and an equal volume of 1% mouse red blood cell suspension, and treat it with 1% Triton-X100 as a positive control. Incubate at 37℃ for 1h, centrifuge at 1000rpm for 10min, aspirate 100μL of supernatant, detect the sample absorbance at 540nm, and draw a hemolysis curve. The hemolysis percentage is calculated as follows: hemolysis percentage (%) = (ODS-ODB) / (ODP-ODB), where ODS represents the absorbance of the sample, ODB represents the absorbance of the blank control (PBS buffer), and ODP represents the absorbance of the positive control. The results are as follows: Figure 7 shown.

[0054] Example 4 Establishment of Mouse Mastitis Model

[0055] (1) After inhalation anesthesia, primiparous and lactating rats were placed in a supine position 4-6 days after delivery. The abdominal mammary glands and the surrounding skin were disinfected with 75% alcohol. A microsyringe was used to infuse Streptococcus agalactiae GS032 through the milk ducts, with 5×10 5 CFU / mL Streptococcus agalactiae resuspension was used to construct the infection model of Streptococcus agalactiae GS032.

[0056] (2) 24 hours after the injection of Streptococcus agalactiae GS032, the antimicrobial peptide analog C18-KGK was started. Before the treatment with the antimicrobial peptide analog C18-KGK, the mother mouse and the pup were separated for 2 hours. After the mammary gland was filled with milk, the mother mouse was anesthetized and 10 μg of the antimicrobial peptide analog C18-KGK solution diluted with sterile PBS was injected through the mammary duct. 2 hours after the drug injection, the mother mouse and the pup were placed in the same cage. The drug was administered once a day for 7 days, and the mice were generally kept for another 2 days after the end of the treatment trial. The condition of the mice was observed every day.

[0057] (3) Each group consisted of 4 mice, and the experimental groups were as follows:

[0058] (i) Group N (control group): mice were not treated;

[0059] (ii) Group P (mastitis group): a mouse mastitis model infected with Streptococcus agalactiae GS032 and not given any treatment;

[0060] (iii) KGK group (antimicrobial peptide analogue treatment group): mice were infected with Streptococcus agalactiae GS032 and were treated with C18-KGK antimicrobial peptide analogue via mammary duct injection.

[0061] (iv) Cefotaxime group (cefotaxime-treated group): mice were infected with Streptococcus agalactiae GS032 to establish a mastitis model and treated with antibiotics (cefotaxime, a broad-spectrum antibiotic commonly used to treat cow mastitis) injected via the mammary duct.

[0062] (4) Mice were infected with Streptococcus agalactiae GS032 at the base of the nipples. The mice in group N were more active, had smooth fur, and ate and drank more frequently. The mice in group P became increasingly sluggish, had messy fur, and drank and ate less frequently. The mice in groups Cefotaxime and KGK drank and ate more frequently than the mice in group P, and their overall mental state was more active.

[0063] In addition, if Figure 8The results show that mice in group N were normal and did not develop mastitis; mice in group P developed mastitis; and mice in group KGK experienced reduced symptoms after treatment for mastitis. Mice in the cefotaxime group also experienced reduced symptoms after treatment for mastitis. This demonstrates that the C18-KGK antimicrobial peptide analog provided by the present invention has therapeutic efficacy for mastitis, achieving an effect at least comparable to that of antibiotics.

[0064] Example 5 Breast Tissue Pathology Section Analysis

[0065] This example performed pathological analysis on the mouse mastitis model constructed in Example 2. The specific experimental steps are as follows:

[0066] 1. Dewax paraffin sections to water: Place the sections in xylene twice, using fresh xylene for 20 minutes each time, then place them in anhydrous ethanol twice, using fresh anhydrous ethanol for 10 minutes each time, followed by the following treatments: 95% ethanol (5 minutes), 90% ethanol (5 minutes), 80% ethanol (5 minutes), 70% ethanol (5 minutes), and then wash with distilled water (10 seconds).

[0067] 2. Staining: Place the sections in hematoxylin solution for 5 minutes, rinse with tap water, and rinse with 1% hydrochloric acid alcohol for 5 seconds until the sections turn light red. Place them under running water to restore the blue color, and then stain with eosin for 3 minutes.

[0068] 3. Dehydration and mounting: Place the sections in 95% alcohol twice, using fresh 95% alcohol for 5 minutes each time, then place them in anhydrous ethanol twice, using fresh anhydrous ethanol for 5 minutes each time, and then place them in xylene twice, using fresh xylene for 5 minutes each time to dehydrate and make them transparent. Take the sections out of the xylene and let them dry slightly. Mount the sections with neutral gum and observe and photograph under a microscope.

[0069] The results are as follows Figure 9 As shown, no obvious inflammatory symptoms were found in the mammary gland sections of mice in group N; obvious inflammatory symptoms were found in the mammary glands of mice in group P, with a large amount of serous fluid and inflammatory cells in the mammary alveoli, and incomplete alveolar structure; fewer inflammatory cells were found in the mammary alveoli of mice in group KGK, with clear boundaries, relatively intact structure, and no interstitial fibrosis; fewer inflammatory cells were found in the mammary alveoli of mice in group Cefotaxime, with clear boundaries, relatively intact structure, and no interstitial fibrosis.

[0070] Example 6 Determination of bacterial load in breast tissue

[0071] In this example, the bacterial load of the mouse mastitis model constructed in Example 2 was determined.

[0072] The specific experimental steps are as follows: 0.1 g of mammary gland tissue was weighed from the experimental mice and homogenized with 0.9 mL of sterile PBS. The homogenate was serially diluted, and 100 μL of each dilution was plated onto a TSB plate. The plate was inverted and incubated at 37°C overnight. Colonies growing on the plate were counted and statistically analyzed.

[0073] The results are as follows Figure 10 As shown, the number of bacteria in the mammary gland tissue of mice treated with C18-KGK was significantly lower than that in the untreated mastitis group (ie, P group) and the antibiotic-treated group (Cefotaxime group).

[0074] Example 7 Determination of inflammatory factors in breast tissue

[0075] In this example, inflammatory factors were measured in the mouse mastitis model constructed in Example 2.

[0076] The specific experimental steps are as follows: Real-time quantitative polymerase chain reaction (qPCR) was used to detect the expression of inflammatory factors in mammary tissue. According to the manufacturer's instructions, total RNA was extracted from mouse mammary tissue using TRIzol reagent. According to the manufacturer's instructions, PrimeScriptTM reverse transcriptase mixed reagent (produced by Nanjing Novozyme Materials Technology Co., Ltd.) was used to synthesize cDNA by reverse transcription. Green Master Mix (High ROX Premixed) (produced by Nanjing Novozyme Materials Technology Co., Ltd.) was used to detect the expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in breast tissue by real-time fluorescence quantitative PCR (qRT-PCR) to determine the degree of inflammation. The primer sequences are shown in Table 2. The reaction system is: Green Master Mix 10μL; reverse primer 0.4μL; forward primer 0.4μL; cDNA 5μL; double distilled water 4.2μL. The reaction conditions are as follows: pre-denaturation, 95℃, 5min; cycle 40 times, 95℃ 10S, 60℃ 30S. The comparative Ct method (2 -ΔΔct ) and normalized the results using the internal reference level of glyceraldehyde-3-phosphate dehydrogenase (GAPDH).

[0077] Table 2 Primer sequences for real-time quantitative PCR

[0078]

[0079] The results are as follows Figure 11 As shown in the figure, the expression levels of IL-6 and TNF-α in the mammary gland tissue of mice in the KGK group were significantly decreased compared with those in the mammary gland tissue of mice in the P group.

[0080] The above examples demonstrate that the C18-KGK antimicrobial peptide analog prepared by the present invention has excellent antimicrobial effects. Furthermore, by establishing a mouse model of mastitis and injecting the C18-KGK antimicrobial peptide analog into the mouse, it was found that the C18-KGK antimicrobial peptide analog also promotes the healing of inflamed tissue. Pathological section observation, bacterial load measurement, and inflammatory cytokine assays confirmed that the C18-KGK antimicrobial peptide has an inhibitory effect on inflammatory factors, thereby promoting the recovery of inflamed tissue.

Claims

1. An N-terminal fatty acid-modified antimicrobial peptide analogue, characterized in that: The antimicrobial peptide analog has a structural formula of: Cn-Lys-Gly-Lys-NH2, wherein Cn is a fatty acid connected to the α-amino group of the N-terminal lysine, and the fatty acid is selected from dodecanoic acid, tetradecanoic acid or octadecanoic acid.

2. The N-terminally fatty acid-modified antimicrobial peptide analog according to claim 1, characterized in that The fatty acid is selected from dodecanoic acid or octadecanoic acid. Preferably, the fatty acid is selected from octadecanoic acid.

3. Use of the N-terminally fatty acid-modified antimicrobial peptide analogue according to claim 1 or 2 in the preparation of antimicrobial drugs / preparations.

4. The use according to claim 3, characterized in that The antibacterial drug / preparation is an anti-Gram-positive bacteria drug / preparation or an anti-Gram-negative bacteria drug / preparation.

5. The use according to claim 4, characterized in that The anti-Gram-positive bacteria drug / preparation is selected from an anti-Streptococcus agalactiae drug / preparation or an anti-Staphylococcus aureus drug / preparation.

6. The use according to claim 4, characterized in that The anti-Gram-negative bacteria drug / preparation is selected from anti-Escherichia coli drugs / preparations.

7. Use of the N-terminally fatty acid-modified antimicrobial peptide analogue according to claim 1 or 2 in the preparation of a medicament / preparation for treating mastitis.

8. The use according to claim 7, characterized in that The mastitis is caused by Streptococcus agalactiae, Staphylococcus aureus or Escherichia coli.

9. The use according to claim 7, characterized in that The mastitis is dairy cow mastitis.

10. Use of the N-terminally fatty acid-modified antimicrobial peptide analogue according to claim 1 or 2 in the preparation of a medicament for reducing inflammation in an organism, wherein the inflammation is caused by Streptococcus agalactiae, Staphylococcus aureus or Escherichia coli.

Images