Bifidobacterium longum as well as preparation and application thereof

Abstract

The invention relates to the technical field of microorganisms, and provides bifidobacterium longum as well as a preparation and application thereof, the bifidobacterium longum is bifidobacterium longum ZZR-JX-11 and is preserved in the China Center for Type Culture Collection on May 17, 2024, the preservation address is Wuhan University, Wuchang District, Wuhan City, Hubei Province, and the preservation number is CCTCC NO: M 2024981. According to the technical scheme, the problems of poor acid resistance of bifidobacterium longum and poor relieving effect on colorectal cancer in related technologies are solved.

Description

Technical Field

[0001] The present invention relates to the field of microbial technology, and in particular to Bifidobacterium longum and a preparation and application thereof. Background Art

[0002] In recent years, the role of the gut microbiome in human health and disease has garnered increasing attention. Trillions of microorganisms inhabit the human intestine, forming a complex symbiotic ecosystem with the host and participating in the regulation of numerous physiological functions. Bifidobacterium longum, a prominent probiotic, plays a key role in maintaining intestinal barrier function, regulating immune responses, and promoting nutrient metabolism.

[0003] However, the existing Bifidobacterium longum on the market focuses on improving intestinal digestive function. There is a lack of Bifidobacterium longum strains and related applications for the specific application scenario of colorectal cancer relief. Existing Bifidobacterium longum has poor acid resistance and a weak effect on colorectal cancer relief. Bifidobacterium longum from different sources and subspecies varies significantly in biological properties and functional activity. Therefore, there is a need to provide a strain of Bifidobacterium longum that has a significant effect on colorectal cancer relief and is acid-resistant. Summary of the Invention

[0004] The present invention provides a Bifidobacterium longum and a preparation and application thereof, which solve the problems in the related art of poor acid resistance of Bifidobacterium longum and poor effect of alleviating colorectal cancer.

[0005] The technical solutions of the present invention are as follows: The present invention provides a Bifidobacterium longum, wherein the Bifidobacterium longum is Bifidobacterium longum ( Bifidobacterium longum ) ZZR-JX-11, deposited in the China Center for Type Culture Collection on May 17, 2024, with the deposit address being Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, with the deposit number being CCTCC NO: M 2024981.

[0006] As a further technical solution, the Bifidobacterium longum ( Bifidobacterium longum ) The 16S rRNA gene sequence of ZZR-JX-11 is shown in SEQ ID NO.1.

[0007] As a further technical solution, the Bifidobacterium longum ( Bifidobacterium longum ) The 16S rRNA gene sequence of ZZR-JX-11 is as follows:

[0008] The present invention also provides a microbial agent, which includes the Bifidobacterium longum ( Bifidobacterium longum )ZZR-JX-11.

[0009] As a further technical solution, the microbial agent includes bacterial powder and / or probiotic solid beverage.

[0010] As a further technical solution, when the microbial agent is solid, the Bifidobacterium longum ( Bifidobacterium longum )The addition amount of ZZR-JX-11 in the microbial agent is not less than 1×10 8 CFU / g; When the microbial agent is non-solid, the Bifidobacterium longum ( Bifidobacterium longum )The addition amount of ZZR-JX-11 in the microbial agent is not less than 1×10 8 CFU / mL.

[0011] The present invention also proposes the use of the Bifidobacterium longum or the microbial agent in the preparation of a drug or food for alleviating colorectal cancer.

[0012] The present invention also proposes the use of the Bifidobacterium longum or the microbial agent in preparing a drug for regulating the increase in expression of tumor suppressor genes related to the prognosis of colorectal cancer patients or in preparing a drug for regulating the decrease in expression of tumor promoting genes related to the prognosis of colorectal cancer patients.

[0013] The present invention also proposes the use of the Bifidobacterium longum or the microbial agent in dairy product fermentation and intestinal health regulation.

[0014] The present invention also proposes the use of the Bifidobacterium longum or the microbial agent in the preparation of a drug that enhances the sensitivity of colorectal cancer to oxaliplatin chemotherapy.

[0015] The present invention also proposes the use of the Bifidobacterium longum or the microbial agent in the preparation of a drug for inhibiting the number and / or volume of colorectal cancer tumors.

[0016] The working principle and beneficial effects of the present invention are: The Bifidobacterium longum ZZR-JX-11 of the present invention is obtained by separation, screening and purification from feces, and the strain morphology and molecular biology are identified. By simulating a gastric fluid environment, it is measured that the Bifidobacterium longum ZZR-JX-11 has good acid resistance. Through cell proliferation experiments, colony formation experiments, experiments on colorectal tumors in mice induced by dextran sodium sulfate + AOM, and sensitization effects on colorectal cancer chemotherapy, it is concluded that the Bifidobacterium longum ZZR-JX-11 can significantly inhibit colorectal tumors, and the combination of ZZR-JX-11 and oxaliplatin can achieve a synergistic effect and synergistically reduce tumor volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Figure 1 This is a plate culture diagram of Bifidobacterium longum ZZR-JX-11 in Example 1 of the present invention; Figure 2 This is a morphological diagram of the strain Bifidobacterium longum ZZR-JX-11 in Example 1 of the present invention; Figure 3 This is a phylogenetic tree diagram of Bifidobacterium longum ZZR-JX-11 in Example 1 of the present invention; Figure 4 This is a diagram showing the results of a cell proliferation experiment in Example 4 of the present invention; Figure 5 This is a graph showing the results of a colony formation experiment in Example 4 of the present invention; Figure 6 This is a diagram showing the results of a sensitization experiment for colorectal cancer chemotherapy in Example 4 of the present invention; Among them, Con was the control group, the strain was the ZZR-JX-11 group, oxaliplatin was the oxaliplatin group, and the strain + oxaliplatin was the ZZR-JX-11 + oxaliplatin group; Figure 7 This is a graph showing the results of electron microscopy detection of exocytic vesicles of Bifidobacterium longum ZZR-JX-11 in Example 4 of the present invention.

[0019] Description of biological material deposit The present invention provides Bifidobacterium longum ( Bifidobacterium longum ) ZZR-JX-11, deposited in China Center for Type Culture Collection, the deposit address is Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, the deposit number is CCTCC NO: M 2024981, and the deposit date is May 17, 2024. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] Preparation method of GAM medium (HB8518-1): Weigh 49.0 g (HB8518-1), dissolve it in 1000 mL of distilled water by heating, sterilize it by high pressure at 121°C for 15 minutes, and when cooled to 50°C, add 1 mL of sterile 0.1% vitamin K1 solution (HB8462a) and 1 mL of hemin (5 mg / mL) (2100500) per 1000 mL of medium, and add 5 mg of filter-sterilized mupirocin lithium salt (HB0384-6a) per 100 mL of medium, mix well and set aside.

[0022] Preparation of TOS selective medium (HB9213): Weigh 62.5 g (HB9213), heat to boil and completely dissolve in 1000 mL of distilled water. Dispense into Erlenmeyer flasks (100 mL per bottle). Autoclave at 115°C for 15 minutes, cool to 50°C, and add 5 mg of filter-sterilized mupirocin lithium salt (HB0384-6a) per 100 mL of medium. Add the medium to culture dishes or glass test tubes and allow to cool.

[0023] Example 1 Screening and identification of strains 1.1 Screening and purification of strains 1.1.1 Screening Take 1g of feces and put it into a sterile tube, dilute it with sterile PBS in a serial ratio, and take 10 -3 , 10 -4 , 10 -5 100 μL of each of the three dilution gradients was evenly spread on TOS selective medium and cultured anaerobically at 37° C. for 48 h for the purification step.

[0024] 1.1.2 Purification Streak a single colony from TOS selective medium and inoculate it into GAM medium. Incubate anaerobically at 37°C for 24 hours. After incubation, examine the colony for purity using a microscope. If contaminants are still present, repeat the streaking, picking, incubation, and microscopic examination steps until a single, pure strain is obtained.

[0025] 1.1.3 Cryopreservation Take the bacterial liquid in the GAM medium with good growth status, add 500 μL of the bacterial liquid and 50% glycerol sterilized by high pressure into the freezing tube, shake it up and down evenly, put it into the programmed cell freezing box, and then put it into the -80℃ refrigerator to obtain the frozen Bifidobacterium longum ZZR-JX-11.

[0026] 1.2 Identification of strains 1.2.1 Identification of strain morphology The screened Bifidobacterium longum ZZR-JX-11 was inoculated on GAM medium and cultured at 37°C for 24 hours. The size, shape, color, glossiness, ridge shape, transparency, edge characteristics, etc. of the colonies were observed under a microscope (1000X).

[0027] Results: The plate culture of Bifidobacterium longum ZZR-JX-11 is shown in the figure below. Figure 1 As shown, the morphology of Bifidobacterium longum ZZR-JX-11 strain is as follows Figure 2 As shown, through Figure 2 Analysis showed that Bifidobacterium longum ZZR-JX-11 was in the shape of straight rods or slightly curved long rods with blunt ends, and existed singly or in pairs.

[0028] 1.2.2 Molecular biological identification of strains The frozen Bifidobacterium longum ZZR-JX-11 in 1.1.3 was sent to Wuhan Tianyi Huayu Gene Technology Co., Ltd. for sequencing. Based on the obtained 16S rRNA sequence, a blast search of homologous sequences in GenBank showed that it was identical to Bifidobacterium longum ( Bifidobacterium longum ) with a homology of up to 100%. The 16S rRNA gene sequence of Bifidobacterium longum ZZR-JX-11 is shown in SEQ ID No. 1. The Neighbor-Joining phylogenetic tree of Bifidobacterium longum ZZR-JX-11 constructed based on the 16S rRNA gene sequence alignment results with Micrococcus luteus DSMZ 20030 (AJ536198) as the outer branch is shown in the figure. Figure 3 shown.

[0029] Example 2 Physiological and biochemical characteristics of strains 2.1 Determination of enzyme activity of strains The enzyme activity of Bifidobacterium longum ZZR-JX-11 was determined using conventional protocols in the art.

[0030] Table 1 Determination results of enzyme activity of Bifidobacterium longum ZZR-JX-11

[0031] Note: “+” indicates a positive reaction; “-” indicates a negative reaction.

[0032] As shown in Table 1, Bifidobacterium longum ZZR-JX-11 has significant glycosidase and short-chain esterase activities, and is suitable as a dietary fiber metabolism probiotic. This strain has outstanding potential in the fields of dairy fermentation, intestinal health regulation and functional ingredient conversion.

[0033] 2.2 Determination of carbon source acid production of strains The carbon source acid production of the strain was determined using conventional methods in the art.

[0034] Table 2 Determination results of carbon source acid production of Bifidobacterium longum ZZR-JX-11

[0035] Note: “+” indicates a positive reaction; “-” indicates a negative reaction.

[0036] As shown in Table 2, Bifidobacterium longum ZZR-JX-11 has a high efficiency in metabolizing monosaccharides, disaccharides and some oligosaccharides to produce acid, and is suitable as a dairy product starter or probiotic candidate.

[0037] Example 3 Determination of acid resistance of strains 3.1 Strain recovery (1) Preparation before the test: 37℃ water bath, high pressure culture medium, anaerobic culture bag, anaerobic bag, shake tube, and ultraviolet disinfection in the biosafety cabinet for 30 minutes.

[0038] (2) Take a shake tube and add 9 mL of mupirocin lithium GAM medium (the preparation method is the same as the preparation method of the aforementioned GAM medium (HB8518-1)); (3) Take a frozen tube of Bifidobacterium longum ZZR-JX-11, place it in a 37℃ water bath, shake it gently, and after it is completely thawed, take out the cryotube, disinfect it with alcohol, and then open the cryotube in a biosafety cabinet after burning it with an alcohol lamp. Pour the bacterial solution into the shake tube and blow it evenly. (4) Cover the shake tube lid (do not fasten the lid tightly), place it in a pre-sterilized anaerobic bag, and put in a 2.5L anaerobic bag. Fasten the bag tightly and place it in a 37℃ incubator for 24~48h. When the OD600nm spectrophotometric value of the MRS culture solution is distributed between 1.2 and 1.5, count the viable bacteria and obtain the culture solution. Store it in a 4℃ refrigerator for later use.

[0039] 3.2 Determination of strain acid resistance (1) After centrifuging the bacterial solution in 3.1 (4), resuspend the bacteria in sterile saline (or PBS) and count them. Then dilute the bacterial solution to 10 10 CFU / 200μL.

[0040] (2) Setting up experimental and control groups: Experimental group: Use a sterile measuring cylinder (or sterile pipette) to take 10 mL of artificial gastric fluid for later use. Artificial gastric fluid was purchased from Solebro, artificial gastric fluid SGF (sterile), product number: A7921.

[0041] Control group: Use a sterile measuring cylinder (or a sterile pipette) to measure 10 mL of normal saline or PBS for later use.

[0042] (3) Take 200 μL of bacterial solution and add it to the experimental group or control group. Mix well and incubate at 37°C. Start timing.

[0043] (4) The experiment was terminated at 1 hour, 2 hours, and 3 hours respectively. Each tube was divided into 3 parts, and the absorbance was measured and the viable bacteria were counted. The survival rate of Bifidobacterium longum ZZR-JX-11 after treatment with artificial gastric juice was calculated. Survival rate = (number of viable bacteria in the experimental group after the experiment - number of viable bacteria in the control group after the experiment) / number of viable bacteria in the bacterial solution before the experiment × 100%. Method for determining viable bacterial count: (1) Mix the bacterial solution by pipetting, take 100 μL of the bacterial solution for dilution, observe the bacterial morphology under a microscope and count the bacteria; (2) Take 1 mL of the mixed bacterial solution and add it to a centrifuge tube containing 9 mL of physiological saline. Invert and mix to make 10 -1 Dilution, draw 1mL 10 -1 The dilution solution was prepared into 10 -2 diluent, dilute to 10 -9 diluent, Take 10 -6 , 10 -7 , 10 -8 , 10 -9 0.1 mL of each of the four dilutions was applied evenly to an agar plate. The plate and anaerobic bag were placed in an anaerobic bag and sealed. The plate was placed in a 37°C incubator for 24 hours. The number of viable bacteria (CFU / mL) was calculated as the actual average value of the plate count × 10 × the dilution factor. When the density was appropriate, the bacterial solution was centrifuged at 3000 rpm for 5 minutes, resuspended and inoculated into 25 mL of culture medium for cultivation. Subsequent experiments were conducted to determine the survival rate after treatment for 1 hour, 2 hours, and 3 hours by measuring absorbance and counting under a microscope. Absorbance: Prepare a 96-well plate, add 100 μl of the test bacterial solution to each well, and measure the OD 600nm Numerical value, OD=1, about 10 8 CFU / mL.

[0044] Counting under the microscope: dilute the bacterial solution to an appropriate multiple, stain with trypan blue, drop it into a bacterial counting plate, and count under the microscope.

[0045] The measurement results are shown in the following table; Table 3 Results of acid resistance test of strains

[0046] As shown in Table 3, the Bifidobacterium longum ZZR-JX-11 of the present invention has good acid resistance.

[0047] Example 4 Determination of the Inhibition of Colorectal Cancer by Strain 4.1 Cell proliferation assay (1) Add 100 μL of colorectal cancer cell SW1463 suspension to each well of a 96-well plate. Usually, about 1000 colorectal cancer cells SW1463 are added to each well in a cell proliferation experiment.

[0048] (2) Colorectal cancer cells SW1463 were cultured in a 5% CO2 cell culture incubator at 37°C for 24 hours.

[0049] (3) After 8 hours of co-culture with Bifidobacterium longum ZZR-JX-11, antibiotics (100u / mL penicillin and 100μg / mL streptomycin) were added to terminate the culture.

[0050] (4) After the 96-well plate is cultured in a cell culture incubator at 37°C, 5% CO2 air and 100% humidity (the culture time is based on the reagent instructions), 10 μL of CCK-8 solution is added to each well.

[0051] (5) After adding CCK-8, place the 96-well plate back into a 37°C, 5% CO2 incubator and incubate for 1 to 4 hours. Different cell types may require different incubation times. Generally, OD 450nm The linearity is best when the value is between 0.8 and 1.5.

[0052] (6) Use a microplate reader to measure the absorbance (OD value) of each well at 450 nm. Colorectal cancer cells SW1463 that were not treated with Bifidobacterium longum ZZR-JX-11 were used as controls and recorded as the control group. Empty culture medium was used as blank and recorded as blank group.

[0053] (7) Calculate the cell viability, cell viability = (ODsample-ODblank) / (ODcontrol-ODblank) × 100%. The measurement results are as follows: Figure 4 shown.

[0054] Depend on Figure 4 It can be seen that when the number of viable bacteria of Bifidobacterium longum ZZR-JX-11 of the present invention is ≥1×10 9 CFU can inhibit the survival of colorectal cancer cells.

[0055] 4.2 Colony formation assay (1) SW1463 colorectal cancer cells in the logarithmic growth phase were seeded into a 6-well plate at a density of 600 cells per well.

[0056] (2) After 8 hours of co-culture of colorectal cancer cells SW1463 and Bifidobacterium longum ZZR-JX-11, antibiotics (100 u / mL penicillin and 100 μg / mL streptomycin) were added to terminate the culture.

[0057] (3) Colorectal cancer cells SW1463 were cultured continuously for 2 weeks.

[0058] (4) After washing with PBS solution, fix with 4wt% paraformaldehyde solution for 3 hours, then add crystal violet staining solution to each well to stain the cells. After 20 minutes, wash with ddH2O and dry. Count the colonies in each well and perform statistical analysis. The results are shown in the table below. Figure 5 shown.

[0059] Depend on Figure 5 It can be seen that the Bifidobacterium longum ZZR-JX-11 of the present invention can inhibit the colony formation of cells, and as the number of viable cells of Bifidobacterium longum ZZR-JX-11 increases, the colony formation of cells can be significantly inhibited.

[0060] 4.3 Inhibitory effect of strain ZZR-JX-11 on colorectal tumors in mice induced by dextran sulfate sodium salt + AOM Purchase 5-week-old Balb / c mice, feed them normally for one week, and use them for the experiment.

[0061] The specific experiment was as follows: 2 mg / mL streptomycin was administered in drinking water for three days before the start of the experiment; on the first day of the experiment, mice were intraperitoneally injected with 200 μL of 10 mg / kg AOM (control group and intervention group) or normal saline (pure negative control); the ZZR-JX-11 intervention group was given 10 mg / kg AOM (control group and intervention group) from the first day. 9 Mice were gavaged with 100 CFU / 200 μL of DSS per day and then daily. A control group received an equal volume of saline until the experiment was terminated. One week later, at 7 weeks of age, mice were fed 2% DSS drinking water or normal drinking water, followed by normal drinking water at 8 weeks of age, for a total of three cycles. Afterwards, mice were fed normal drinking water, and sacrificed at 14, 16, and 18 weeks of age.

[0062] Groups: control group (AOM / DSS treatment + PBS intragastric administration of normal saline), ZZR-JX-11 (10 9 CFU / 200 μL) intervention group (AOM / DSS treatment + ZZR-JX-11 gavage), each group had 15 mice.

[0063] Compare the differences in tumor number and volume between the ZZR-JX-11 intervention group and the control group.

[0064] The measurement results are shown in the following table.

[0065] Table 4 Inhibitory effect of strains on colorectal tumor formation in mice

[0066] As shown in Table 4, compared with the saline control group, the number of tumors in the ZZR-JX-11 intervention group was significantly reduced, and the volume of each tumor was also significantly reduced. This indicates that Bifidobacterium longum ZZR-JX-11 has a significant inhibitory effect on the occurrence and development of colorectal tumors.

[0067] 4.4 Tumor-related gene regulatory characteristics of the strain RNA was extracted from tumor tissues and cells using the Trizol method to verify RNA quality. Appropriate RNA was used to construct libraries and quantitatively analyze the libraries for quality verification. Raw data were obtained through sequencing using the Illumina sequencing platform. Sequence information was annotated through data quality control and sequence alignment. Differential expression analysis was performed using the R programming languages DESeq2 and edgeR. The results are shown in the table below.

[0068] Table 5 Regulatory effects of strains on the expression of colorectal cancer-related genes

[0069] As shown in Table 5, DDX60 and TREH are tumor suppressor genes, and their high expression is associated with a better prognosis, and Bifidobacterium longum ZZR-JX-11 can promote their expression.

[0070] 4.5 Sensitization of colorectal cancer cells to chemotherapy by strain ZZR-JX-11 Establishment of a subcutaneous colorectal cancer model in mice using the CT26 cell line 6-8 week old Balb / c mice were inoculated with CT26 cells and randomly divided into control group, ZZR-JX-11 group, oxaliplatin group, and ZZR-JX-11+oxaliplatin group. 9 CFU / 200μL ZZR-JX-11 was administered orally (the oral volume was 200μL), and oxaliplatin 10mg / kg was given starting from the third day of modeling. 6 CT26 cells. After injection, gently press with a sterile cotton swab for a moment to prevent cells from flowing out along the needle hole. A slight bulge in the skin at the inoculation site can be seen. After implantation, monitor the weight changes and tumor size of the mice. The experiment is terminated one month after modeling. The tumor size is measured with a vernier caliper, and the longest diameter (a) and the maximum transverse diameter (b) of the tumor in the perpendicular direction are measured. According to the formula V (mm 3 ) = ab 2 / 2Calculate the tumor volume, the measurement results are as follows Figure 6 shown.

[0071] pass Figure 6Analysis showed that Bifidobacterium longum ZZR-JX-11 has a certain anti-colorectal cancer effect, and when ZZR-JX-11 and oxaliplatin are used in combination, the degree of reduction in tumor volume is significantly greater than when either is used alone, indicating that the combination of Bifidobacterium longum ZZR-JX-11 and oxaliplatin can achieve a synergistic effect.

[0072] 4.6 Exocytic vesicles of strain ZZR-JX-11 After culturing Bifidobacterium longum ZZR-JX-11 for 16 to 20 hours, 100 to 200 mL of the supernatant was collected and centrifuged at low temperature (100,000 rpm) using an ultracentrifuge. After rinsing with PBS, the supernatant was examined by electron microscopy.

[0073] The electron microscopy results are as follows Figure 7 As shown by Figure 7 It can be seen that Bifidobacterium longum ZZR-JX-11 is a Bifidobacterium longum that can secrete vesicles.

[0074] In addition, mass spectrometry revealed that the Bifidobacterium longum ZZR-JX-11 of the present invention can also secrete the following human homologous functional protein polypeptides, as shown in the following table.

[0075] Table 6 Information on human homologous protein polypeptides secreted by strains

[0076] As shown in Table 6, Bifidobacterium longum ZZR-JX-11 can also secrete the human homologous functional protein polypeptides in the above table, which can provide nutrients for beneficial bacteria in the intestine, regulate the balance of intestinal flora, and directly or indirectly activate the intestinal immune system, improve intestinal immune function, promote intestinal absorption of nutrients and many other benefits.

[0077] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A Bifidobacterium longum, characterized in that The Bifidobacterium longum is Bifidobacterium longum ( Bifidobacterium longum ) ZZR-JX-11, deposited in the China Center for Type Culture Collection on May 17, 2024, with the deposit address being Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, with the deposit number being CCTCC NO: M 2024981.

2. The Bifidobacterium longum according to claim 1, wherein The Bifidobacterium longum ( Bifidobacterium longum ) The 16S rRNA gene sequence of ZZR-JX-11 is shown in SEQ ID NO.

1.

3. A microbial agent, characterized in that: The microbial agent includes the Bifidobacterium longum ( Bifidobacterium longum )ZZR-JX-11.

4. A microbial agent according to claim 3, characterized in that: The microbial agent includes bacterial powder and / or probiotic solid beverage.

5. The microbial agent according to claim 3, characterized in that When the microbial agent is solid, the Bifidobacterium longum ( Bifidobacterium longum )The addition amount of ZZR-JX-11 in the microbial agent is not less than 1×10 8 CFU / g; When the microbial agent is non-solid, the Bifidobacterium longum ( Bifidobacterium longum )The addition amount of ZZR-JX-11 in the microbial agent is not less than 1×10 8 CFU / mL.

6. Use of the Bifidobacterium longum according to any one of claims 1 to 2 or the microbial agent according to any one of claims 3 to 5 in the preparation of a drug for alleviating colorectal cancer.

7. Use of the Bifidobacterium longum according to any one of claims 1 to 2 or the microbial agent according to any one of claims 3 to 5 in the preparation of a drug for regulating the increase in expression of tumor suppressor genes associated with the prognosis of colorectal cancer patients or in the preparation of a drug for regulating the decrease in expression of oncogenes associated with the prognosis of colorectal cancer patients.

8. Use of the Bifidobacterium longum according to any one of claims 1 to 2 or the microbial agent according to any one of claims 3 to 5 in dairy product fermentation and intestinal health regulation.

9. Use of the Bifidobacterium longum according to any one of claims 1 to 2 or the microbial agent according to any one of claims 3 to 5 in the preparation of a drug that enhances the sensitivity of colorectal cancer to oxaliplatin chemotherapy.

10. Use of the Bifidobacterium longum according to any one of claims 1 to 2 or the microbial agent according to any one of claims 3 to 5 in the preparation of a drug for inhibiting the number and / or volume of colorectal cancer tumors.

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