Plant lactobacillus and application thereof

Abstract

The invention discloses a plant lactobacillus and application thereof, and belongs to the technical field of microorganisms. The plant lactobacillus 002P provided by the invention is a new strain, and is round, white, neat in edge, smooth in surface and soft in texture on an MRS solid culture medium; growth of bacteria can be remarkably inhibited, an inhibition effect on staphylococcus aureus, pseudomonas aeruginosa and escherichia coli is achieved, and the inhibition zone is 23.33-279.33 mm; the healing of infected wounds can be obviously promoted; the selenium conversion rate is excellent, and the maximum selenium conversion rate can reach 88%; the nano-selenium prepared from the plant lactobacillus 002P is spherical, has the particle size of 200-500nm, has excellent properties of resisting oxidation, relieving hepatotoxicity induced by saturated fatty acid, promoting expression of selenoprotein in a mouse body and reducing blood fat, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms, in particular to a Lactobacillus plantarum strain and application thereof. Background Art

[0002] Lactic acid bacteria are a type of non-spore-forming, Gram-positive bacteria. The main product of their fermentation of sugars is lactic acid. They are widely present in nature and have significant probiotic properties. From a classification point of view, lactic acid bacteria include several genera such as Lactobacillus, Streptococcus, and Bifidobacterium. Among them, Lactobacillus plantarum ( Lactobacillus plantarum As a representative lactic acid bacteria, Lactobacillus plantarum possesses advantages such as stable morphology, strong metabolic activity, and high biosafety. In recent years, Lactobacillus plantarum has become a key research target in the fields of biomedicine and functional foods due to its antioxidant, anti-inflammatory, and wound healing properties.

[0003] Selenium is an essential trace element that plays a crucial role in antioxidant function, immune regulation, and metabolic homeostasis. As a core component of glutathione peroxidase and selenoproteins, selenium has demonstrated promising biological effects in preventing and treating cancer, cardiovascular disease, and immune disorders. However, the narrow dosage window and high toxicity of inorganic selenium limit its application. Therefore, developing safe and effective selenium supplementation is crucial.

[0004] In recent years, nanoselenium has become a research hotspot in the field of functional food and biomedicine due to its low toxicity, high bioactivity and unique physicochemical properties. Nanoselenium can not only enhance antioxidant capacity, but also regulate inflammatory responses, reduce oxidative stress and tissue damage. However, the traditional chemical method for preparing nanoselenium has problems such as low yield, high cost and environmental pollution. In comparison, the biosynthesis of nanoselenium using microbial metabolic systems such as probiotics has significant advantages: (1) The process is green and environmentally friendly, avoiding toxic intermediates and wastewater pollution in chemical synthesis; (2) The generated nanoselenium has good biocompatibility and can be directly used in the fields of food and medicine; (3) By optimizing the strain culture conditions, the particle size and surface properties of nanoselenium can be precisely controlled, thereby achieving efficient and customized production. Summary of the Invention

[0005] The purpose of the present invention is to provide a Lactobacillus plantarum strain and its application, and to provide a new Lactobacillus plantarum strain with high nano-selenium conversion efficiency and strong antioxidant capacity of the prepared nano-selenium.

[0006] To achieve the above object, the present invention provides Lactobacillus plantarum 002P, which is classified and named as Lactobacillus plantarum 002P Lactiplantibacillus plantarum 002P, deposited in the China Center for Type Culture Collection on December 9, 2024, with the deposit address being Wuhan University, and the deposit number being CCTCC NO: M 20242757.

[0007] The use of Lactobacillus plantarum 002P as described above in the preparation of nano-selenium.

[0008] Nano-selenium prepared by Lactobacillus plantarum 002P as described above.

[0009] The use of the Lactobacillus plantarum 002P or nano-selenium as described above in the preparation of an antibacterial preparation, wherein the bacteria in the antibacterial preparation are bacteria, including Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli.

[0010] The use of the Lactobacillus plantarum 002P or nano-selenium as described above in the preparation of a preparation for promoting wound healing, wherein the preparation contains Lactobacillus plantarum 002P.

[0011] Use of the Lactobacillus plantarum 002P or nano-selenium as described above in the preparation of antioxidant preparations.

[0012] Use of the Lactobacillus plantarum 002P or nano-selenium as described above in the preparation of cell protection preparations.

[0013] The use of Lactobacillus plantarum 002P or nano-selenium as described above in the preparation of an immunity enhancing preparation.

[0014] The use of the above-mentioned Lactobacillus plantarum 002P or nano-selenium in the preparation of health-care foods and skin-care products is characterized in that the health-care foods include fermented milk.

[0015] The use of Lactobacillus plantarum 002P or nano-selenium as described above in the preparation of liver protection targeted drugs.

[0016] Therefore, the present invention provides a plant lactobacillus and its application, and its specific technical effects are as follows: (1) The Lactobacillus plantarum 002P provided by the present invention is a new strain that appears round, white, with neat edges, a smooth surface, and a soft texture on MRS solid culture medium; (2) The Lactobacillus plantarum 002P provided by the present invention can significantly inhibit the growth of bacteria, and is effective against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, with an inhibition zone of 23.33-279.33 mm; (3) Both the live and inactivated Lactobacillus plantarum 002P bacteria provided by the present invention can significantly promote the healing of infected wounds; (4) The Lactobacillus plantarum 002P provided by the present invention has an excellent selenium conversion rate of up to 88%; the nano-selenium prepared from Lactobacillus plantarum 002P is spherical with a particle size of 200-500 nm, has excellent antioxidant properties, protects liver cells and promotes the expression of selenoproteins in mice, and has broad application prospects.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0019] Figure 1 is a colony of Lactobacillus plantarum 002P in Example 1 of the present invention; Figure 2 is the Gram staining result of Lactobacillus plantarum 002P in Example 1 of the present invention; Figure 3 is the phylogenetic tree of Lactobacillus plantarum 002P constructed in Example 1 of the present invention; Figure 4 These are photos of mouse wounds after being treated with Lactobacillus plantarum 002P for different periods of time in Example 3 of the present invention; Figure 5 is the statistical result of the wound healing rate in Example 3 of the present invention; Figure 6 TEM and EDS images of the nano-selenium prepared in Example 4 of the present invention; a is the TEM image; b is the EDS image; Figure 7 This is the statistical result of the nano-selenium conversion rate in Example 4 of the present invention; Figure 8 is the statistical result of the DPPH clearance rate of nano-selenium in vitro in Example 5 of the present invention; wherein <0.0001 means P <0.0001; Figure 9 is the statistical result of the hepatocyte survival rate in Example 6 of the present invention; wherein <0.0001 means P <0.0001; Figure 10 is the statistical result of total glutathione peroxidase activity in cells in Example 6 of the present invention; wherein 0.0001 represents P =0.0001; Figure 11 This is a Western Blot image in Example 7 of the present invention; Figure 12 is the statistical result of serum triglyceride TG content in Example 7 of the present invention; wherein 0.0014 represents P =0.0014.

[0020] Lactobacillus plantarum 002P, classified as Lactobacillus plantarum 002P Lactiplantibacillus plantarum 002P, deposited in the China Center for Type Culture Collection on December 9, 2024, with the deposit address being Wuhan University, and the deposit number being CCTCC NO: M 20242757. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0022] In order to make the purpose, technical solutions and advantages of the present application clearer, more thorough and more complete, the technical solutions of the present invention are clearly and completely described below through the accompanying drawings and Examples. The following detailed description is an explanation of the embodiments and is intended to provide further details of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the application belongs.

[0023] The instruments, equipment, reagents and materials used in the examples were obtained from commercial sources; the method steps not described in detail are conventional techniques in the art.

[0024] The composition of MRS liquid culture medium is as follows: glucose 20 g / L, peptone 10 g / L, yeast powder 5 g / L, beef extract 8 g / L, sodium acetate 5 g / L, dipotassium hydrogen phosphate 2 g / L, ammonium citrate 2 g / L, Tween-80 1 g / L, magnesium sulfate 0.58 g / L, manganese sulfate 0.25 g / L, calcium carbonate 8 g / L, Congo red 0.05 g / L, pH 5.7, sterilized at 121°C for 30 min.

[0025] The composition of MRS solid culture medium is as follows: on the basis of the above liquid culture medium, 15 g / L agar is added.

[0026] All significant analyses were performed using Student's t-test. P Value display.

[0027] Example 1 The characteristics of Lactobacillus plantarum 002P are as follows: (1) Morphological characteristics: The colony of Lactobacillus plantarum 002P after culturing on MRS solid medium for 2 days is shown in the figure below. Figure 1 Shown: round, white, with neat edges, smooth surface and soft texture.

[0028] (2) Physiological and biochemical characteristics: Lactobacillus plantarum 002P was stained with crystal violet for 1 minute, reinforced with iodine solution for 1 minute, decolorized with alcohol and then restained with safranin for 1 minute. The results are as follows: Figure 2As shown, Lactobacillus plantarum 002P is Gram-positive, grows from top to bottom in solid culture medium, and produces acid by fermentation using glucose as a carbon source.

[0029] (3) Taxonomic characteristics: The genomic DNA of Lactobacillus plantarum 002P was extracted using a kit, and the high-quality genomic DNA was used as a template. PCR amplification was performed using the PCR universal primers of the 16S rRNA gene (the sequence is shown in SEQ ID NO.2). The amplified product was sent to the company for Sanger sequencing. The 16S rRNA sequence of Lactobacillus plantarum 002P was obtained as shown in SEQ ID NO.1. The maximum likelihood method was used to perform homology comparison with the sequences in the GenBank database, and the phylogenetic tree of Lactobacillus plantarum 002P was constructed. The results are shown in Figure 3 As shown, the target strain is similar to Lactobacillus plantarum ( Lactobacillus plantarum ) has the highest sequence similarity of 99%.

[0030] SEQ ID NO.1: CCGGGGGGGGTGCCCTATACATGCAGTCGAACGAACTCTGGTATTGATTGGTGCTTGCATCATGATTTACATTTGAGTGAGTGGCGAACTGGTGAGTAACACGTGGGAAACCTGCCCAGAAGCGGGGGATAACACCTGGAAACAGATGCTAATACCGCATAACAACTTGGACCGCATGGTCCGAGTTTGAAAGATGGCTTCGGCTATCACTTTTGGATGGTCCCGCGGCGTATTAGCTAGATGGTGGGGTAACGGCTCACCATGGCAATGATACGTAGCCGACCTGAGAGGGTAATCGGCCACATTGGGACTGAGACACGGCCCAAACTCCTACGGGAGGCAGCAGTAGGGAATCTTCCACAATGGACGAAAGTCTGATGGAGCAACGCCGCGTGAGTGAAGAAGGGTTTCGGCTCGTAAAACTCTGTTGTTAAAGAAGAACATATCTGAGAGTAACTGTTCAGGTATTGACGGTATTTAACCAGAAAGCCACGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGTGGCAAGCGTTGTCCGGATTTATTGGGCGTAAAGCGAGCGCAGGCGGTTTTTTAAGTCTGATGTGAAAGCCTTCGGCTCAACCGAAGAAGTGCATCGGAAACTGGGAAACTTGAGTGCAGAAGAGGACAGTGGAACTCCATGTGTAGCGGTGAAATGCGTAGATATATGGAAGAACACCAGTGGCGAAGGCGGCTGTCTGGTCTGTAACTGACGCTGAGGCTCGAAAGTATGGGTAGCAAACAGGATTAGATACCCTGGTAGTCCATACCGTAAACGATGAATGCTAAGTGTTGGAGGGTTTCCGCCCTTCAGTGCTGCAGCTAACGCATTAAGCATTCCGCCCTGGGGAGTACGGCCGCAAGGCTGAAACTCAAAGGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGAAGCTA SEQ ID NO.2: AGAGTTTGATCATGGCTCAG Example 2 The antibacterial activity of Lactobacillus plantarum 002P was investigated as follows: (1) Preparation of indicator bacterial suspension: Staphylococcus aureus CMCC(B) 26003, Pseudomonas aeruginosa CMCC(B) 10104 and Escherichia coli CMCC(B) 44102 were activated and cultured respectively. The activated bacteria were then inoculated into liquid LB medium at a 2% inoculum and cultured at 37°C and 220 rpm for 12 h. After the time was up, the suspension was centrifuged at 6500 rpm for 5 min. The resulting bacterial pellet was washed twice with physiological saline and the bacterial solution concentration was adjusted to 1×10 8 CFU / mL, used for antibacterial test.

[0031] (2) Preparation of Lactobacillus plantarum 002P suspension: The activated Lactobacillus plantarum 002P was inoculated into MRS liquid culture medium at a 2% inoculum rate, cultured at 37°C and 220 rpm for 24 h, and centrifuged at 6500 rpm for 5 min after the culture. The obtained bacterial precipitate was washed twice with physiological saline, and the bacterial solution concentration was adjusted to 5×10 5 The resuspended bacterial solution and the supernatant collected from the culture precipitate were used for the antibacterial test.

[0032] (3) Antibacterial test was performed using the Oxford cup method. MRS solid culture medium with an agar concentration of 1.5% was poured into the plate and solidified to obtain an MRS plate. After the solid culture medium of MRS and LB was melted, it was mixed in a volume ratio of 1:1. When the culture medium was cooled to 45-50°C, the indicator bacterial suspension prepared in step (1) was added at a 1% inoculum volume. After mixing evenly, it was poured onto the prepared MRS plate. After the plate solidified, it was placed in an Oxford cup. 200 μL of the supernatant or resuspended bacterial solution of Lactobacillus plantarum 002P was added to the Oxford cup. The plate was placed in a 37°C incubator and cultured until a clear inhibition zone appeared. This was used as the experimental group. The same method was used, and the same amount of physiological saline was added to the Oxford cup as the control group. Five biological replicates were set for each treatment, and the diameter of the inhibition zone was measured using a vernier caliper.

[0033] The results are shown in Table 1. Lactobacillus plantarum 002P showed good antibacterial effects on the three indicator bacteria, with inhibition zones ranging from 23.33 to 279.33 mm.

[0034] Table 1. Inhibition zone diameters of 002P against three strains (n=5, mean ± SD) ;

[0035] Note: a, e, ae, adc indicate significant differences compared with the control group of the corresponding strain ( P <0.05), different letters indicate significant differences among the groups; the same letters indicate insignificant differences.

[0036] Example 3 The effects of Lactobacillus plantarum 002P on wound healing were investigated as follows: (1) Cultivation of Lactobacillus plantarum 002P: Inoculate Lactobacillus plantarum 002P into 100 mL of MRS liquid culture medium and culture in a shaking incubator at 30°C and 200 rpm until the OD value of the bacterial solution reaches 0. 600 =3.0, and finally adjust the bacterial solution concentration to 5×10 5 CFU / mL refers to viable bacterial suspension.

[0037] (2) Establishment of mouse skin wound infection model: C57BL / 6J mice (half male and half female, weighing 22-25 g, 5-6 weeks old) were anesthetized with isoflurane and their back hair was removed using an electric shaver and depilatory cream. After disinfection with 75% ethanol, a full-thickness skin wound with a diameter of 10 mm was created using sterile surgical scissors in the disinfected area. 20 μL of 1×10 6 After taking photos and recording, the wound was covered with 1624W dressing. The 1624W dressing was a simple physical barrier without additional dressing or drugs. All wound experiments were administered for the first time immediately after modeling, and then again on the 3rd, 5th, 7th, and 9th days of inoculation.

[0038] (3) The mice modeled in step (2) were randomly divided into three groups, with 5 mice in each group: 002P live bacteria group: Remove the 1624W dressing and drip 20 μL of the Lactobacillus plantarum 002P bacterial solution prepared in step (1) onto the skin wound of the infected model mice.

[0039] 002P inactivated bacteria group: The Lactobacillus plantarum 002P bacterial solution prepared in step (1) was inactivated at 121°C for 20 minutes and cooled to room temperature in a clean bench to obtain the inactivated Lactobacillus plantarum 002P bacterial solution. The 1624W dressing was removed, and 20 μL of the inactivated Lactobacillus plantarum 002P bacterial solution was dripped onto the skin wound of the infected model mouse and covered with a new dressing.

[0040] Control group (CON): The 1624W dressing was removed and 20 μL of 0.9% saline was dripped onto the skin wound of the infected model mice.

[0041] The mice in each group were fed with conventional diet.

[0042] The wound healing process under the 1624W dressing was observed and photographed for 9 consecutive days, and the wound area was calculated using Image J as a control data. Figure 4 and Figure 5 As shown in the figure, when both were inoculated with Staphylococcus aureus, the 002P live bacteria group and the 002P inactivated bacteria group showed significant differences from the control group starting from the third day of treatment, indicating that Lactobacillus plantarum 002P or its metabolites have a positive effect on wound healing in mice.

[0043] Example 4 The effects of Lactobacillus plantarum 002P on the synthesis of nano-selenium were investigated as follows: (1) Synthesis: Inoculate Lactobacillus plantarum 002P into 100 mL of MRS liquid culture medium and culture in a shaking incubator at 30°C and 200 rpm until the OD value of the bacterial solution reaches 600 =3.0.

[0044] 1% (v / v) Lactobacillus plantarum 002P culture was inoculated into 400 mL of MRS liquid medium containing final concentrations of 150 μg / mL, 200 μg / mL, and 300 μg / mL sodium selenite, respectively. The pH was adjusted to pH 6, pH 7, and pH 8, respectively, using 1 M HCl and NaOH. Three biological replicates were set for each treatment. The culture was then shaken at 37°C and 250 rpm for 72 h, centrifuged at 12,000 rpm and 4°C for 10 min, and the precipitate was collected, washed three times with pure water, and resuspended in 20 mL of 0.9% saline.

[0045] (2) Purification: The bacterial suspension prepared in step (1) was sonicated using an ultrasonic disruptor at a power of 400 W, with sonication every 6 seconds for 30-50 min until the cells were broken. The suspension was then washed three times with 1.5 M Tris-HCl (pH 8.3) containing 1% sodium dodecyl sulfate (SDS) and centrifuged at 12,000 rpm for 10 min. The precipitate was resuspended in 20 mL of sterile water, and n-butanol was added. The solution was vigorously mixed and centrifuged at 2,000 rpm at 4°C for 5 min.

[0046] The mixture was then placed at -4°C for 24 hours. The precipitate was transferred to a sterile 50 mL centrifuge tube and washed sequentially with chloroform, 100% ethanol, 70% ethanol, and deionized water. The precipitate was collected by centrifugation at 12,000 rpm for 5 minutes. The precipitate was washed with sterile deionized water and freeze-dried to obtain elemental selenium nanoparticles (002PSeNPs).

[0047] The supernatant after the culture precipitation was collected and the amount of unconverted sodium selenite was detected by DAB (3,3'-diaminobenzidine) colorimetric method. The conversion rate (%) was calculated by the following formula (m is mass): Conversion rate %= .

[0048] The results are as follows Figure 7 As shown, the maximum conversion rate of selenium by Lactobacillus plantarum 002P is 88%, which is higher than the conversion rate of Lactobacillus plantarum in the prior art (such as Wang L, Song L, Wang P, et al. Bioreduction of Se(IV) byLactiplantibacillus plantarum NML21 and synthesis of selenium nanospheres Se(0)[J]. Food Chemistry, 2024, 452(000):11. DOI:10.1016 / j.foodchem.2024.139595 and Chinese patent CN 117126759 A). In three independent biological replicate experiments, the maximum amount of nano-selenium product obtained was 6.58g, 7.32g and 8.04g, respectively. This shows that the method provided by the present invention has good repeatability and high yield, is superior to the prior art, and is significantly different from the sodium selenite group when a student's t test is performed.

[0049] The nano-selenium obtained in step (2) was characterized by transmission electron microscopy (TEM) for morphology and elements. Figure 6 As shown, the nano-selenium is spherical with a particle size of 200-500nm, and the element analysis of TEM-EDS Mapping is selenium (Se).

[0050] Example 5 The ability of Lactobacillus plantarum 002P and the nano-selenium prepared in Example 4 to scavenge DPPH in vitro was investigated as follows: The DPPH free radical scavenging kit was used to determine the DPPH scavenging rate of the following groups of samples. The DPPH working solution concentration was 0.1 mM and was dissolved in anhydrous ethanol. Six treatments were set up: 1. Lactobacillus plantarum 002P live bacterial solution group, the bacterial solution was taken from Example 4 (1); 2. Nano-selenium group (the nano-selenium obtained in Example 4 was dissolved in sterile deionized water to prepare a 0.2 mg / mL working solution); 3. Positive control group (using vitamin C, VC, at a concentration of 0.2 mg / mL); 4. Yeast selenium group (using yeast selenium patches, the aqueous solution concentration was 0.2 mg / mL); 5. Sodium selenite control group (sodium selenite with a purity of 99%, the aqueous solution concentration was 0.2 mg / mL).

[0051] Each sample group was replicated three times. 200 μL of sample solution was taken from each sample group and mixed with DPPH reagent at a volume ratio of 1:1. After reacting in the dark for 30 minutes, the absorbance was measured at a wavelength of 517 nm. The DPPH free radical scavenging rate was calculated according to the following formula: DPPH free radical scavenging rate%= , Where: A0 is the absorbance value of the sample replaced by an equal volume of anhydrous ethanol; A1 is the absorbance value of the experimental group; A2 is the absorbance value of the DPPH replaced by an equal volume of anhydrous ethanol (used to deduct the background absorbance of the sample itself).

[0052] The results are as follows Figure 8 As shown in the results, the DPPH scavenging rate of the 002P live bacteria liquid is 58%, and the DPPH scavenging rate of the nano-selenium prepared in Example 4 is 71%, which is significantly higher than that of common yeast selenium (39%) and sodium selenite (30%), indicating that the nano-selenium prepared in the present invention has a stronger DPPH scavenging rate and better antioxidant potential.

[0053] Example 6 The nano-selenium obtained by probiotic transformation in Example 5 was investigated to see whether it has an alleviating effect on saturated fatty acid-induced hepatotoxicity, as follows: Fatty liver cell model group (palmitic acid group): AML12 (Alpha Mouse Liver 12) cells were purchased from the Cell Bank of Type Culture Collection, Chinese Academy of Sciences, Shanghai. Cells were cultured at 37°C and 5% CO2 in Dulbecco's Modified Eagle Medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 1× insulin-transferrin-selenium (ITS), 40 ng / mL dexamethasone, and 1% penicillin-streptomycin. When the cells reached 80-90% confluency, they were plated at 1×10 5 Cells were seeded in 96-well plates at a rate of 100 cells / well, with five replicates per group. The control group received only standard culture medium. AML12 cells in the experimental groups (PA, nanoselenium, and sodium selenite) were treated with 200 mM saturated fatty acid (palmitic acid) at 37°C for 24 hours to establish a fatty liver cell model. After treatment, cell viability was assessed using the Cell Counting Kit-8 in both the control and experimental groups.

[0054] Nano-selenium treatment group: AML12 cells were treated with 600 nM nano-selenium prepared in Example 4 and palmitic acid (treated at 37° C. for 24 hours).

[0055] Sodium selenite control group: AML12 cells were treated with 900 nM sodium selenite and palmitic acid (37°C for 24 hours), and then cell viability was detected using Cell Counting Kit-8.

[0056] The results are as follows Figure 9 As shown, compared with the fatty liver cell model group, the cell death rate in the nano-selenium treatment group was significantly reduced. When the addition amount was 600nM, the survival rate increased to 82%, which was better than that of higher doses of sodium selenite.

[0057] The total glutathione peroxidase kit was used to detect the glutathione peroxidase activity in cells after nano-selenium treatment. Figure 10 As shown in the results, the glutathione peroxidase activity in the cells of the nano-selenium treatment group increased by 5 times compared with the control group and the fatty liver cell model group, indicating that nano-selenium can significantly enhance the activity of selenoprotein glutathione peroxidase in cells, inhibit oxidative stress and thus alleviate the cytotoxicity induced by saturated fatty acids.

[0058] Example 7 The effects of the nano-selenium prepared in Example 5 on the expression of selenoproteins in mouse liver tissue and blood lipids in a fatty liver mouse model were investigated as follows: (1) Construct a fatty liver model.

[0059] C57BL / 6 mice (half male and half female, weighing 22-25g, 5-6 weeks old) were fed an XTMCD diet for 8 weeks to establish a high-fat diet model. The experimental groups were divided into a control group, a high-fat diet model group, and a nano-selenium group. The nano-selenium group served as the treatment group and, in addition to the high-fat diet, received daily oral administration of the 002PSeNPs prepared in Example 4. Following the conclusion of the experiment, the mice were sacrificed and immediately after cardiac blood sampling and liver tissue collection.

[0060] (2) Liver protein extraction and Western Blot experiment.

[0061] An appropriate amount of liver tissue was collected from n = 2 mice per group. Pre-chilled RIPA lysis buffer (containing protease inhibitors) was added and thoroughly homogenized using a tissue homogenizer. The samples were centrifuged at 12,000 rpm for 15 minutes at 4°C, and the supernatant was collected. Protein concentration was determined using the BCA assay, and the protein samples were adjusted to a uniform concentration. The protein samples were mixed with loading buffer, denatured by boiling, and then separated by electrophoresis on SDS-PAGE gels. The separated proteins were transferred to a PVDF membrane and blocked with 5% skim milk for 1 hour at room temperature. Antibodies against Gpx4 and Txnrd1 (1:1000 dilution) were used as primary antibodies, and the membranes were incubated overnight at 4°C. After washing with TBST, HRP-conjugated secondary antibodies (1:5000 dilution) were added and incubated for 1 hour at room temperature. The membranes were developed using a chemiluminescence kit, and the signals were acquired using an imaging system. Western blot bands were analyzed for grayscale intensity using Image J software. The expression levels of the target proteins (selenoproteins Txnrd1 and Gpx4) were normalized to β-actin and Gapdh as internal controls. The results are as follows Figure 11 As shown in the results, compared with the high-fat model group, the expressions of thioredoxin reductase 1 (Txnrd1) and glutathione peroxidase 4 (Gpx4) in the nano-selenium group were significantly increased.

[0062] (3) Mouse serum separation and serum TG (triglyceride) detection.

[0063] The collected blood was collected in a common centrifuge tube and placed at room temperature for 30 minutes, then centrifuged at 3000 rpm for 10 minutes. The supernatant was tested with a TG kit according to the instructions and colorimetrically detected using an enzyme-labeled instrument at a wavelength of 510 nm. The results were as follows. Figure 12 As shown, compared with the high-fat model group, the TG content in the serum of mice in the nano-selenium group was lower, indicating that Lactobacillus plantarum 002P and the nano-selenium produced by it can significantly reduce the blood lipids of high-fat model mice.

[0064] Therefore, the Lactobacillus plantarum 002P provided by the present invention is a new strain, which appears round, white, with neat edges, a smooth surface and a soft texture on MRS solid culture medium; can significantly inhibit the growth of bacteria, and is effective against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, with an inhibition zone of 23.33-279.33 mm; can significantly promote the healing of infected wounds; has an excellent selenium conversion rate, and can convert inorganic selenium into nano-selenium with low toxicity and high bioavailability, with a conversion rate of up to 88%; the nano-selenium prepared from Lactobacillus plantarum 002P is spherical and has a particle size of 200-500 nm, has excellent antioxidant properties, can significantly alleviate saturated fatty acid-induced hepatocellular toxicity and promote the expression of selenoproteins in mice, and has broad application prospects.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. Lactobacillus plantarum 002P, characterized in that: Lactobacillus plantarum 002P is classified and named as Lactobacillus plantarum 002P Lactiplantibacillus plantarum 002P, deposited in the China Center for Type Culture Collection on December 9, 2024, with the deposit address being Wuhan University, and the deposit number being CCTCC NO: M 20242757.

2. Use of plant lactobacillus 002P as claimed in claim 1 in the preparation of nano-selenium.

3. Nano-selenium prepared by Lactobacillus plantarum 002P as claimed in claim 1.

4. The use of the plant lactobacillus 002P according to claim 1 or the nano-selenium according to claim 3 in the preparation of an antibacterial preparation, characterized in that: The bacteria in the antibacterial preparation are bacteria, including Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli.

5. Use of the Lactobacillus plantarum 002P according to claim 1 or the nano-selenium according to claim 3 in preparing a preparation for promoting wound healing, characterized in that: The preparation contains Lactobacillus plantarum 002P.

6. Use of the Lactobacillus plantarum 002P according to claim 1 or the nano-selenium according to claim 3 in the preparation of an antioxidant preparation.

7. Use of the Lactobacillus plantarum 002P according to claim 1 or the nano-selenium according to claim 3 in the preparation of a cell protection preparation.

8. Use of the Lactobacillus plantarum 002P according to claim 1 or the nano-selenium according to claim 3 in the preparation of an immunity-enhancing preparation.

9. Use of the Lactobacillus plantarum 002P according to claim 1 or the nano-selenium according to claim 3 in preparing health foods and skin care products, characterized in that: The health food comprises fermented milk.

10. Use of the Lactobacillus plantarum 002P according to claim 1 or the nano-selenium according to claim 3 in the preparation of a targeted liver protection drug.

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