450 results about "Uronic acid" patented technology

The invention discloses a lactobacillus mucus fermentation strain and application thereof, and provides a lactobacillus mucus fermentation strain A10 with high yield of exopolysaccharides, and the preservation number of the lactobacillus mucus fermentation strain A10 is CCTCC (China Center for Type Culture Collection) NO: M20242082. The fermented lactobacillus mucus A10 has relatively strong bile salt and gastrointestinal tract digestion tolerance and has an obvious antibacterial effect on escherichia coli and staphylococcus aureus, and the exopolysaccharide synthesized by the fermented lactobacillus mucus A10 is Wzy type exopolysaccharide, is heteropolysaccharide composed of rhamnose, galactose, glucose, mannose and glucuronic acid, and can be used for preparing the exopolysaccharide. The product has good thermal stability and antioxidant activity, and can significantly scavenge free radicals. The lactobacillus mucus A10 extracellular polysaccharide provided by the invention can exert antioxidant activity by activating a Keap1-Nrf2 / ARE signal channel, and is expected to be developed into a natural antioxidant which interacts with Keap1-Nrf2 in a targeting manner.

The invention provides modified acidic polysaccharide of lithocarpus litseifolius. The modified acidic polysaccharide is prepared from natural acidic polysaccharide of lithocarpus litseifolius through a chemical method or an enzyme method. Every 100 mg of the modified acidic polysaccharide of lithocarpus litseifolius contains 89.75 mg + / -1.04 mg to 90.67 mg + / -1.46 mg of total polysaccharide. The total uronic acid content is 23.70 mg + / -1.58 mg to 71.74 mg + / -2.07 mg; total bound phenol: 2.06 mg of GAE + / -0.06 mg of GAE-4.56 mg of GAE + / -0.04 mg of GAE (equivalent weight of gallic acid); the esterification degree is 3.72% + / -0.90% to 34.98% + / -0.62%; the molecular weight is (0.562 + / -0.012) * 10 < 4 > Da-(4.268 + / -0.055) * 10 < 4 > Da; the proportion of the galacturonic acid glycan (HG) is 15.28% to 65.02%; the ratio of the type I rhamnogalacturonan (RG-I) is 28.47% to 72.37%; and the length of a side chain is 0.44 to 10.31. The invention further provides a preparation method and application of the lithocarpus litseifolius modified acidic polysaccharide. The lithocarpus litseifolius modified acidic polysaccharide prepared by the invention has remarkable immunoregulatory activity, and especially has better immunocompetence when being used for removing arabinose side chains and reducing galactose side chains.

The invention provides homogenized pitaya polysaccharide as well as a preparation method and application thereof, and belongs to the technical field of polysaccharide extraction and purification. The homogenized pitaya polysaccharide is a polysaccharide of which the monosaccharide is composed of mannose, glucosamine hydrochloride, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose, the relative molecular weight is 8.08 * 10 < 4 > Da, and the corresponding molar ratio is (0.181): (0.250): (16.544): (12.762): (3.793): (0.739): (51.014): (14.716). The invention further provides a preparation method of the homogenized pitaya polysaccharide and application of the homogenized pitaya polysaccharide in preparation of lipid-lowering and sugar-lowering drugs. The homogenized pitaya polysaccharide disclosed by the invention has an obvious lipid-lowering and blood-glucose-reducing effect, is from a natural product, so that the homogenized pitaya polysaccharide has no toxic or side effect and can be used for preparing lipid-lowering and blood-glucose-reducing medicines.

The invention discloses application of a ganoderma lucidum strain SS30 in preparation of a product for treating cancers, and belongs to the technical field of biology. The invention provides ganoderma lucidum strain SS30 mycelium polysaccharide. The ganoderma lucidum strain SS30 mycelium polysaccharide is prepared from glucose, galactose, mannose, fucose, xylose, arabinose, rhamnose, glucuronic acid, glucosamine, ribose and lacturonic acid. The polysaccharide has a remarkable effect of inhibiting transplantable pancreatic cancer and primary colorectal cancer, can achieve the effect of treating cancer by improving the immune function and reducing the oxidation product generation level, provides a new material for development and utilization of lucid ganoderma and products thereof, and has a wide application prospect. And a research basis is provided for research and development of cancer-related drugs and research of a cancer treatment mechanism.

The invention relates to the field of establishment of fingerprints of traditional Chinese medicinal materials, in particular to an establishment method and application of a salvia miltiorrhiza polysaccharide HPLC (High Performance Liquid Chromatography) fingerprint. The establishment method comprises the following steps: preparation of a test solution: taking a salvia miltiorrhiza polysaccharide hydrolysis solution, carrying out derivatization in a reaction bottle, and passing through a 0.1-0.3 [mu] m microporous filter membrane; preparing a reference substance solution, namely weighing mannose, ribose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose reference substances, and preparing into a mixed reference substance solution; performing HPLC (high performance liquid chromatography) determination; and establishing the salvia miltiorrhiza polysaccharide HPLC fingerprint spectrum. According to the method, the difference of monosaccharide composition and content in salvia miltiorrhiza medicinal materials from different producing areas and the spectrum-effect relationship between antioxidant activity and anticoagulant activity are clarified, and a certain reference basis is provided for quality control and evaluation of the salvia miltiorrhiza medicinal materials from the aspect of polysaccharide.

The subject of this invention is to use beneficial reactive support media or biofilms in the form of reactive support bases or stratums that provide structural (including dimensions) or biochemical benefits to the growth or function (including agglutination) of biofilms. The functional aspect includes the provision of reactivity to a polymeric, cellulosic or silicic framework. The functions are supplied to the structural media during manufacture, conditioning, regeneration or during colonization of biofilms. The structural support media may include biodegradable or refractory polymers / plastics, alginates or uronic acids or extracted bacterial EPS. These materials are reacted, retained or removed based on their physical characteristics.

The invention discloses a beta-glucuronidase inhibitor composition as well as a preparation method and application thereof. The composition is prepared from the following substances: ursolic acid, procyanidine, icariin, curcumin, epigallocatechin gallate and glycyrrhetinic acid. The beta-glucuronidase inhibitor composition has a broad-spectrum and good inhibition effect, the preparation method is simple, large-scale production is easy, and the inhibitor with a natural source is higher in use compliance, lower in toxic and side effects and more suitable for developing intestinal health products and has an application prospect.

The invention relates to gardenia polysaccharide as well as a preparation method and application thereof. The gardenia polysaccharide comprises the following monosaccharide units: rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose, or mainly comprises rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose; the molar ratio of rhamnose to glucuronic acid to galacturonic acid to glucose to galactose to arabinose in the gardenia polysaccharide is (3-15): (1-8): (4-18): (1-6): (15-35): (25-70). According to the gardenia polysaccharide, FFA induced mouse primary parenchymal hepatic cell lipid accumulation can be reduced, no obvious cytotoxic effect exists, CDAHFD diet induced hepatic fibrosis can be reduced, and the gardenia polysaccharide has a good effect of preventing and / or treating non-alcoholic steatohepatitis.

The present invention discloses a fermented mucus lactobacillus and its application. The present invention provides a fermented mucus lactobacillus A10 with high extracellular polysaccharide production, and its deposit number is CCTCC NO: M20242082. The fermented mucus lactobacillus A10 has strong bile salt and gastrointestinal digestion tolerance, and has obvious antibacterial effects on Escherichia coli and Staphylococcus aureus. The extracellular polysaccharide synthesized by the fermented mucus lactobacillus A10 is a Wzy type extracellular polysaccharide, which is a heteropolysaccharide composed of rhamnose, galactose, glucose, mannose, and glucuronic acid. It has good thermal stability and antioxidant activity, and can significantly scavenge free radicals. The fermented mucus lactobacillus A10 extracellular polysaccharide provided by the present invention can exert antioxidant activity by activating the Keap1-Nrf2 / ARE signaling pathway, and is expected to be developed into a natural antioxidant that interacts with Keap1-Nrf2 in a targeted manner.

The invention discloses a genetically engineered bacterium for producing glucuronic acid as well as a construction method and application of the genetically engineered bacterium, and belongs to the technical field of genetic engineering. According to the genetically engineered bacterium for producing glucuronic acid, an inositol oxidase gene MMIOX is integrated on a site of a uronic acid isomerase gene uxaC. According to the invention, an inositol oxidase gene MMIOX is integrated on a genome of a genetically engineered bacterium for producing glucuronic acid, and a uronic acid isomerase gene uxaC is knocked out at the same time, so that the genetically engineered bacterium can efficiently catalyze inositol reaction to generate glucuronic acid through the integrated inositol oxidase gene MMIOX; the glucuronic acid isomerase gene uxaC is knocked out, so that isomerization reaction of glucuronic acid can be avoided, and the yield of glucuronic acid is further increased.

The invention provides a Cladosporium Colombiae strain D5-11, a bacterial fertilizer, a soil conditioner and application of the Cladosporium Colombiae strain D5-11, and belongs to the technical field of microorganisms. The preservation number of the cladosporium taro strain D5-11 is CGMCC (China General Microbiological Culture Collection Center) No.41143. The cladosporium taro strain D5-11 promotes agglomeration of saline-alkali soil by secreting extracellular polymers uronic acid and humic acid, and the saline-alkali environment for plant survival is effectively improved; the cladosporium taro strain D5-11 has strong alkali resistance, can improve the activity of microorganisms in an alkaline environment, and is suitable for saline-alkali farmlands. In addition, the cladosporium taro strain D5-11 can also improve the oxidation resistance of the plant in a saline-alkali environment.

The invention relates to the field of medicines, foods or health-care products, in particular to big-fruit hawthorn heteropolysaccharide as well as a preparation method and application thereof. The large-fruit hawthorn heteropolysaccharide is prepared from galacturonic acid, glucuronic acid, mannose, xylose, arabinose, glucose, galactose, fucose and rhamnose. The weight-average molecular weight of the big fruit hawthorn heteropolysaccharide is 81.6 kDa to 157.3 kDa. The product has unique structures of complex monosaccharide composition, low molecular weight, appropriate uronic acid content, low esterification degree and the like; compared with CP which is single in structure and high in esterification, the CP is better in oxidation resistance and bile acid binding capacity; compared with hawthorn polysaccharide with low uronic acid content and high molecular weight, the hawthorn polysaccharide has the advantages that the enzyme inhibition activity is obviously enhanced, and the hawthorn polysaccharide has a wide prospect in development of functional food, health care products or medicines for regulating blood sugar / blood fat, resisting oxidation and preventing metabolic syndromes.

The invention provides a Chinese date modified acidic polysaccharide. Each 100 mg of the Chinese date modified acidic polysaccharide contains 90.26 mg + / -1.39 mg to 94.42 mg + / -1.83 mg of total polysaccharide, the total uronic acid content is 21.42 mg + / -1.01 mg to 50.72 mg + / -0.62 mg; total bound phenol: 0.65 mg of GAE + / -0.05 mg of GAE-1.21 mg of GAE + / -0.03 mg of GAE (equivalent weight of gallic acid). The invention also provides a preparation method and application of the jujube modified acidic polysaccharide. The jujube acidic polysaccharide is modified through a low-temperature alkaline deesterification technology, a directional enzyme digestion technology and a controllable partial acid hydrolysis technology, the in-vivo and in-vitro immunomodulatory activity of the jujube acidic polysaccharide before and after modification is compared, and the immunomodulatory activity of the jujube modified acidic polysaccharide obtained through modification is remarkably enhanced; especially, the jujube modified acidic polysaccharide with araban side chains removed and galactan side chains reduced has better immunocompetence.

The invention belongs to the technical field of gene engineering, and discloses recombinant yarrowia lipolytica as well as a construction method and application thereof. The recombinant yarrowia lipolytica PGA1 is obtained by carrying out heterologous expression on an arabidopsis thaliana inositol oxygenase gene and a pseudomonas syringae uronic acid dehydrogenase gene in the yarrowia lipolytica by utilizing a genetic engineering technical means. The recombinant yarrowia lipolytica PGA10 capable of efficiently synthesizing glucaric acid (GA) is finally obtained by further modifying six genes of related metabolic pathways of the recombinant yarrowia lipolytica PGA1. The GA yield of the PGA10 reaches 2233.24 mg / L and is 66.27 times that of PGA1, and the effect is remarkable. The invention not only constructs a GA synthesis method, but also defines the influence of related genes such as opi1 on GA synthesis, and provides reference for the research of heterologous synthesis of GA by microorganisms.

The specification relates to conjugates comprising a linker of Formula (IA):and pharmaceutically acceptable salts thereof. The specification also relates the use of the conjugates for the treatment of diseases such as cancer, and intermediates useful for the synthesis of the conjugates.

The invention relates to the technical field of plant polysaccharides, and particularly discloses a red-knees herb polysaccharide and a preparation method and application thereof, the peak top molecular weight of the red-knees herb polysaccharide is 33.9 KDa, the weight-average molecular weight of the red-knees herb polysaccharide is 42.8 KDa, the number-average molecular weight of the red-knees herb polysaccharide is 10.0 KDa, and the red-knees herb polysaccharide is mainly composed of galacturonic acid, galactose, arabinose, rhamnose and glucuronic acid. According to the preparation method of the red-knees herb polysaccharide, by optimizing process parameters and controlling the reasonable solid-liquid ratio, heating temperature and heating time, the dissolution rate of the polysaccharide is increased, the dissolution rate of impurities is reduced, and the yield of the red-knees herb polysaccharide is increased. The red-knees herb polysaccharide is used as a raw material, ethanol is used for alcohol precipitation, polysaccharide components are precipitated, impurities are preliminarily removed, then macroporous resin is used for purification, the recovery rate of polysaccharide and the removal rate of impurities such as pigment and protein are improved by screening optimization and pretreatment of the macroporous resin, and the total sugar content of the purified red-knees herb polysaccharide is 80% or above. Use of toxic chemical reagents is avoided, and the preparation method is safe and efficient.

The invention discloses a raspberry homogeneous polysaccharide. The monosaccharide components of the raspberry homogeneous polysaccharide comprise fucose, rhamnose, arabinose, galactose, xylose, galacturonic acid, glucuronic acid and apiose. The main chain structure of the raspberry homogeneous polysaccharide is 1, 4-linked galacturonic acid pyranose, and the weight-average molecular weight of the raspberry homogeneous polysaccharide is 8.54 + / -5.0 kDa. The invention discloses a raspberry homogeneous polysaccharide component for inhibiting dietary oil absorption and preventing and improving obesity, which is prepared by the steps of water extraction and alcohol precipitation, ion exchange chromatographic column elution and permeation gel chromatographic column elution. The structure of the compound is analyzed by high performance gel permeation chromatography, infrared spectroscopy, ion chromatography, gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy. The homogeneous polysaccharide component can be used for improving obesity and fat tissue accumulation hypertrophy, and the efficacy of the homogeneous polysaccharide component is related to inhibition of absorption of dietary oil in the intestinal tract and promotion of discharge of the dietary oil into the body.

The invention belongs to the technical field of biological medicines, and particularly relates to an alkali-extracted saffron petal polysaccharide APPCS-1a as well as a preparation method and application thereof. The APPCS-1a provided by the invention is uniform polysaccharide, has the molecular weight of about 40KDa, better thermal stability, no triple helix, more negative charges and good antioxidant activity, and can be applied to preparation of anti-aging medicines, health care products or cosmetics. According to the extraction method of APPCS-1a, an alkali extraction and alcohol precipitation method is adopted, the extracted polysaccharide is rich in uronic acid, good in biological activity and wide in biological application value, and the extraction method is simple, low in cost and suitable for industrial mass production.

The invention relates to the field of microbial strains edited by gene recombination and synthetic biology, and provides recombinant escherichia coli for synthesizing D-xylose by using glucose and application. The recombinant escherichia coli comprises the following modifications: exogenous insertion of a gene IRX for coding beta-1, 4-xylosyltransferase; exogenous insertion of a gene UXS encoding a UDP-glucuronic acid decarboxylase; the invention relates to enhanced expression or overexpression of a gene yagH for coding beta xylosidase. Compared with a traditional hemicellulose hydrolysis method for producing D-xylose, the method for synthesizing and preparing D-xylose through whole-cell catalysis of D-glucose by using the recombinant escherichia coli has the advantages of environmental protection, cost advantage and energy saving.

The invention relates to the technical field of biology, in particular to a recombinant strain for producing glucuronic acid and application of the recombinant strain. The invention provides a recombinant strain for producing glucuronic acid, and the recombinant strain does not express uronic acid isomerase and overexpresses inositol oxidase. The technical scheme of the invention has the following advantages: (1) uronic acid isomerase uxaC from escherichia coli K12 is knocked out, so that glucuronic acid accumulation is increased; and (2) successfully integrating the target gene of the inositol oxidase from the mouse into the escherichia coli K12MG1655. And (3) when the engineering strain is used for catalyzing inositol, the content of glucuronic acid in a system after the reaction is finished is 52.50 g / L, and the conversion rate is as high as 97.23%.

The invention relates to an intestinal probiotic genetically engineered bacterium as well as a construction method and application thereof, and belongs to the technical field of genetic engineering. According to the invention, Escherichia coli is used as an expression host, endogenous recessive plasmid pMUT1 gene and pMUT2 gene are knocked out, an exo-algin lyase gene and an open-loop uronic acid monomer dehydrogenase gene are subjected to heterologous expression, and a 2-keto-3-deoxy-gluconate kinase gene and a 2-keto-3-deoxy-6-phosphate-gluconate aldolase gene are subjected to overexpression. According to the invention, an endogenous recessive plasmid pMUT2 of Escherichia coli Nissle 1917 is utilized, metabolic pathways of algin and degradation products thereof are introduced, and a stable passage engineered strain EcNc-pMUT2 '-4 which can be proliferated by utilizing algin and degradation products thereof and is free of antibiotic markers is obtained, and the engineered strain has good intestinal tract probiotic performance.

The invention discloses raspberry leaf polysaccharide as well as a preparation method and application thereof. The average relative molecular weight of the raspberry leaf polysaccharide is 44755 Da, and the raspberry leaf polysaccharide is mainly prepared from mannose, glucose, rhamnose, glucosamine, galactosamine, glucuronic acid, galactose, xylose and arabinose according to the molar ratio of (3.138): (0.894): (12.349): (4.590): (26.498): (18.681): (22.842): (2.690): (8.317). Besides, methylation and nuclear magnetic resonance analysis show that the raspberry leaf polysaccharide is complex polysaccharide, and it can be reasonably deduced that the raspberry leaf polysaccharide is mainly composed of a large number of HG structural domain-like structures and a part of RG-I structures with side chains. Meanwhile, the raspberry leaf polysaccharide disclosed by the invention can be used for inhibiting the injury of kidney tissues and reducing the generation of kidney inflammatory factors.

The invention discloses tartary buckwheat vinasse polysaccharide with antioxidant activity and a preparation method of the tartary buckwheat vinasse polysaccharide, and belongs to the technical field of polysaccharide. The molecular weight of the tartary buckwheat vinasse polysaccharide with the antioxidant activity is 3.84 * 10 < 5 >, and the monosaccharide is prepared from Man-mannose, Rib-ribose, Rham-rhamnose, GlcUA-glucuronic acid, GalUA-galacturonic acid, Glc-glucose, Gal-galactose, Xyl-xylose and Ara-arabinose according to the molar ratio of (41.60): (20.20): (1.70): (2.84): (4.45): (8.90): (14.39): (6.27): (5.82). The tartary buckwheat vinasse polysaccharide is subjected to crude extraction through an ultrasonic-assisted water extraction and alcohol precipitation method, the extracted crude polysaccharide is purified through ion exchange column and sephadex column chromatography, and the prepared tartary buckwheat vinasse polysaccharide has a good scavenging effect on ABTS < + > free radicals, DPPH free radicals and hydroxyl free radicals and has antioxidant activity.

The invention provides a method for extracting acacetin-7-O-glucuronide from dracocephalum moldavica, and relates to the technical field of medicine extraction. The method comprises the following steps: heating and extracting dracocephalum moldavica or dracocephalum moldavica products by adopting an alkaline solution, and precipitating the obtained extracting solution under the condition that the pH value is 1-3 to obtain a precipitate extract; mixing n-hexane, ethyl acetate, ethanol and water, and layering to obtain an upper phase solution and a lower phase solution; and dissolving the precipitate extract with a lower-phase solution, carrying out high-speed counter-current chromatography separation on the obtained sample solution, and collecting an acacetin-7-O-glucuronide fraction according to a chromatogram. According to the method, alkali extraction, acid precipitation and high-speed counter-current chromatography are combined, process conditions are optimized, the high-purity monomer of acacetin-7-O-glucuronide in dracocephalum moldavica is rapidly prepared, and the process is simple.

The invention provides recombinant escherichia coli for synthesizing glucuronic acid by using glucose and a method for producing glucuronic acid by using the recombinant escherichia coli, and belongs to the field of microbial metabolic engineering. The engineering bacterium is obtained by taking escherichia coli as an original strain and knocking out a glucuronic acid isomerase coding gene uxaC, a 6-phosphofructokinase I coding gene pfkA, a 6-phosphofructokinase II coding gene pfkB and a glucose-6-phosphate dehydrogenase coding gene zwf. The engineering bacterium disclosed by the invention has a good application prospect in industrial production of glucuronic acid.

The invention discloses hippophae rhamnoides polysaccharide with the activity of reducing blood sugar and blood fat as well as a preparation method and application thereof. Adding water into the degreased hippophae rhamnoides, adjusting the pH value to be acidic, then heating, stirring and extracting under an ultrasonic condition, and collecting filtrate; and performing post-treatment to obtain the sea-buckthorn polysaccharide. The content of neutral sugar in the sea buckthorn polysaccharide is 25.31%-30.68%, the content of uronic acid in the sea buckthorn polysaccharide is 54.66%-59.79%, and the content of protein in the sea buckthorn polysaccharide is 1.91%-2.14%. According to the method, the sea-buckthorn polysaccharide is extracted by adopting acid assistance-ultrasonic extraction, and the prepared sea-buckthorn polysaccharide has remarkable blood sugar and blood fat reducing activity. When the concentration of the sea-buckthorn polysaccharide is as low as 0.1 mg / mL, the glucose uptake of HepG2-IR cells can still be obviously improved, and the content of total cholesterol and total triglyceride of the HepG2-IR cells can be obviously reduced. The hippophae rhamnoides polysaccharide can be applied to preparation of food or medicine for reducing blood sugar and / or blood fat.

The invention provides a quality detection method of antiviral particles. The quality detection method adopts HPLC-MS / MS (High Performance Liquid Chromatography-Mass Spectrometry / Mass Spectrometry) to simultaneously determine the following components: forsythiaside A, patchouli ketone, verbascoside, mangiferin, 5-methoxy-8-hydroxypsoralen, curcumenol, luteolin-7-glucuronide, kaempferol-3-O-rutinoside, baicalin, rutin and bergamot phenol. The detection method is a quantitative determination method for 11 active components in the antiviral particles, the detection method is short in time and low in cost, the quantitative analysis method is expected to provide reference for quality control of the antiviral particles, and the clinical curative effect and safety of the antiviral particles are guaranteed.

The invention discloses algin with anti-photoaging activity as well as a preparation method and application of the algin, and belongs to the technical field of deep processing of seaweed. The molecular weight of the algin is 10-350kDa, the total sugar content is 40wt%-80wt%, the reducing sugar content is 3wt%-16wt%, and the uronic acid content is 40wt%-80wt%. The preparation method of the algin specifically comprises the following steps: (1) degrading dielectric barrier discharge plasma; and (2) dialyzing and freeze-drying. The algin can significantly improve the inhibition rate of elastase and the cell survival rate of HaCaT cells after ultraviolet irradiation, has significant anti-photoaging activity, and can be used for developing anti-photoaging functional foods and skin care products. Meanwhile, the preparation method adopting the dielectric barrier discharge plasma is simple and convenient to operate, rapid, efficient, green, environment-friendly and free of addition of exogenous chemical substances, and the molecular weight of the algin can be remarkably reduced, so that the additional value of the algin is improved, the application range of the algin is widened, and the algin has a good application prospect.

The application discloses a method for inhibiting growth of pseudomonas by using fucoidan and application thereof, and is characterized in that the fucoidan is a degradation product of natural seaweed (sodium alginate), and is a linear oligosaccharide with a polymerization degree of 2-25 and composed of guluronic acid and mannuronic acid, and has the advantages of safety, health and no toxic side effects; in combination with the research of the inventors that the fucoidan can target and inhibit growth of pseudomonas in vitro and in intestinal flora, the fucoidan can meet the demand of practical application, can be used for delaying corruption and deterioration of fresh food caused by pseudomonas, and can be used for inhibiting growth of pseudomonas on the surface or in the body of aquatic products or fresh food, and has good application prospect and safety.

The invention provides an application of a detection reagent of five tryptophan metabolites in preparation of an early diagnosis kit for ER (estrogen receptor) positive breast cancer. The tryptophan metabolites are kynurenine Kyn, indole-3-carboxylic acid glucuronide I3GA, indole-3-acetic acid I3A, indole-3-acetyl-L-alanine IAA-L-Ala and L-tryptophan L-Trp. According to the invention, early accurate diagnosis of ER positive breast cancer is realized, and the technical problems of insufficient efficiency of traditional diagnosis means and lack of'combined application 'in existing metabolite research are solved.