1154 results about "Cysteine" patented technology

The invention relates to an indole hair dye based on air oxidation. The hair dye provided by the invention is characterized in that a chemical strong oxidant is not added, and oxygen in air can be catalyzed by using an air oxidation catalyst and a metal ion catalyst to naturally finish the oxidative polymerization process of indole substances (natural bionic melanin precursor substances). The used reducing agent is a combination of cysteine and a derivative thereof and sodium sulfite and a derivative thereof, the oxidative polymerization speed of indole substances can be controlled, and finally generated melanin macromolecules are embedded in hair cortex, so that white hair is obviously blackened. The natural oxidation process does not need hydrogen peroxide, destructive strong base or organic base, so that the use of harmful chemical reagents is reduced, the formula is simplified, the hair dyeing process is milder, potential hazards to hair and scalp are reduced, and the natural oxidation hair dye is safe, environmentally friendly and sustainable.

The invention relates to the technical field of carotenoid cleavage dioxygenase, and discloses a carotenoid cleavage dioxygenase mutant and application thereof. In order to improve the efficiency of converting carotenoid in tobacco into aroma molecule beta-ionone, specific mutation of characteristic sites is carried out on carotenoid cleavage dioxygenase (PhCCD1) from petunia, that is, serine (S) at the 428 site of the carotenoid cleavage dioxygenase is mutated into cysteine (C) or tyrosine (Y) to obtain a mutant S428C or S428Y, and the mutant S428C or S428Y is converted into beta-ionone. The yield of the beta-ionone converted from the carotenoid is greatly improved. Experiments prove that the yields of beta-ionone of S428C and S428Y respectively reach 54.2 mg / L and 50.6 mg / L, which are respectively increased by 69.7% and 58.5% compared with those of a wild strain WT.

The invention relates to the field of plant molecular biology and forest genetic engineering, and particularly provides a PagRAP2.3 protein point mutant and application thereof in drought resistance of poplar. The mutant PagRAP2.3 MA is obtained by mutating methionine at the first site and cysteine at the second site of a wild type PagRAP2.3 protein into methionine and alanine. The invention further discloses a preparation method of the mutant PagRAP2.3. An expression vector containing the PagRAP2.3 MA gene is constructed, poplar 84K is transformed through an agrobacterium-mediated method, and a transgenic line with stable expression is obtained. Functional verification results show that overexpression of PagRAP2.3 MA can significantly increase the plant height of the poplar and promote plant growth, but the sensitivity to moisture is enhanced under drought stress. The mutant can be used for regulating and controlling the growth and development of forest trees and evaluating the drought resistance, and has a forestry breeding application prospect.

The invention discloses a solid-phase microextraction derived fiber head and a preparation method and application thereof, the solid-phase microextraction derived fiber head comprises a solid-phase matrix and polystyrene microspheres adhered to the surface of the solid-phase matrix, and a chitosan cross-linked network layer is also cross-linked on the polystyrene microspheres; cysteine is also adsorbed on the polypropylene microsphere and chitosan cross-linked network layer. According to the solid-phase microextraction derivative fiber head, a large number of hydrophilic action sites such as amino groups and carboxyl groups exist on the surface, so that synchronous extraction and detection of the contents of three target analytes, namely cysteine-chlorothalonil association compounds, sulfydryl chlorothalonil and hydroxychlorothalonil, are realized.

The invention belongs to the technical field of biological medicine, and particularly relates to application of anethomycin in preparation of medicine for inhibiting cysteine protease activity. The invention discovers that anethomycin has the function of inhibiting the activity of virus cysteine protease, especially 3C or 3CL protease, for the first time. Molecular docking proves that anethomycin can effectively bind to the catalytic activity center of Senecavirus (SVA) 3C protease. An in-vitro FRET enzyme activity experiment proves that the inhibition rate of 50 [mu] M of anethomycin on SVA 3C protease reaches up to 88.5%. Cellular level experiments show that the anethomycin can significantly inhibit replication of SVA viruses, shows broad-spectrum antiviral activity on various viruses such as encephalomyocarditis viruses (EMCV), porcine reproductive and respiratory syndrome viruses (PRRSV) and porcine deltacoronaviruses (PDCoV), and is low in cytotoxicity and high in selectivity index (SI).

The invention provides a functional nanofiber material as well as a preparation method and application thereof, and the preparation method comprises the following steps: (1) adding raw materials into water to form an electrostatic spinning solution; performing electrostatic spinning to obtain a nanofiber membrane; (2) cross-linking the nanofiber membrane in an organic solvent under the catalysis of acid to obtain a cross-linked nanofiber membrane; and (3) carrying out grafting reaction on the cross-linked nanofiber membrane in a polyamine cross-linking agent, and then reacting with a sulfur-containing reagent to obtain the functional nanofiber material, the functionalized nanofiber material prepared by the preparation method disclosed by the invention combines good biocompatibility of polyvinyl alcohol, high specific surface area and high porosity of nanofiber and a synergistic adsorption effect of the polyamine cross-linking agent and cysteine, and has the advantages of large adsorption capacity, high adsorption rate, strong selectivity, good biocompatibility, stable structure and the like; the heavy metal ions in the plasma can be efficiently and safely removed, and a plurality of defects of the existing adsorption material are overcome.

The invention discloses a compound environment-friendly corrosion inhibitor as well as a preparation method and application thereof. The choline ionic liquid comprises choline ionic liquid and amino acid, the choline ionic liquid is choline cations; the amino acid is one or more of cysteine and tryptophan. The compound environment-friendly corrosion inhibitor has high corrosion inhibition efficiency, and the compound structure of the compound environment-friendly corrosion inhibitor further improves the protection performance of the compound environment-friendly corrosion inhibitor through a dual adsorption mechanism of the synergistic effect of physical adsorption and chemical adsorption on the metal surface. According to the compound environment-friendly corrosion inhibitor, a full-green ionic liquid corrosion inhibition system is constructed, the environment-friendly requirement is met, and a metal protection solution can be provided for industrial acid pickling and other strong acid working conditions. Not only is the progress of a corrosion inhibition technology promoted, but also more economic and environment-friendly anti-corrosion application can be provided for actual industrial scenes.

The invention belongs to the technical field of electro-catalytic materials and carbon dioxide emission reduction and resource utilization, and particularly relates to an amino acid modified copper-based catalyst and a preparation method and application thereof. According to the catalyst, the surface of cuprous oxide with an orthorhombic-section semi-cube shape is modified through L-cysteine, and a composite structure with a special interface microenvironment is formed. Sulfydryl in L-cysteine and copper species on the surface of cuprous oxide can form a strong coordination effect, water decomposition and * CO protonation are promoted, the surface structure is stabilized, asymmetric coupling is facilitated, meanwhile, amino can provide an electron-rich environment, capture of carbon dioxide is enhanced, and the selectivity and stability of ethylene prepared through electro-catalysis carbon dioxide reduction are cooperatively regulated and controlled.

The invention belongs to the technical field of medicines, and particularly relates to a hydrogel dressing for promoting healing of diabetic wounds as well as a preparation method and application of the hydrogel dressing. According to the hydrogel dressing for promoting healing of the diabetic wound, glycyrrhizic acid and S-allyl-L-cysteine are used as raw materials, a buffer solution is used as a dispersion medium, and the glycyrrhizic acid and S-allyl-L-cysteine are compounded and self-assembled by controlling the mass ratio of the raw materials, the reaction temperature, the reaction time and the pH value. The hydrogel shows tissue-like viscoelasticity characteristics, can adaptively deform along with wound movement, provides continuous protection for chronic wounds under dynamic physiological conditions, and has flexibility of adapting to dynamic requirements in different healing stages.

The invention provides an electrolyte additive for synergistically regulating and controlling activity and stability of an all-vanadium redox flow battery and application of the electrolyte additive, the electrolyte additive is a composite additive of an organic amino acid compound and inorganic phosphate, the organic amino acid compound is one of aspartic acid, glycine and cysteine, and the inorganic phosphate is one of amino acid, glycine and cysteine. The inorganic phosphate is one or two or more of phosphate, dihydric phosphate, dihydric phosphate, polyphosphate and pyrophosphate, and cations of the inorganic phosphate are one or two or more of potassium, sodium and ammonium salt. The composite additive is used as an electrolyte additive to be added into an all-vanadium redox flow battery electrolyte, so that the vanadium electrolyte can be effectively prevented from generating precipitates at high temperature, the capacity fading in the battery operation process is avoided, and the stable operation of the battery is realized. The preparation process is simple to operate, energy-saving, environment-friendly and low in cost, and stable operation of the electrolyte in the battery can be realized.

The invention discloses an amino acid composition for treating alopecia and application of the amino acid composition in preparation of a medicine for treating alopecia, and belongs to the field of medicine configuration products, the amino acid composition is composed of a targeting core intervention component and an auxiliary strengthening synergistic component, the targeting core intervention component is prepared from 30-50 parts of arginine, 50-155 parts of lysine and 50-120 parts of glutamic acid, and the auxiliary strengthening synergistic component is prepared from an auxiliary strengthening synergistic component and an auxiliary strengthening synergistic component. 10 to 40 parts of cysteine and 20 to 60 parts of leucine; the auxiliary strengthening synergistic component is prepared from 15 to 45 parts of tyrosine, 15 to 40 parts of glycine, 10 to 40 parts of glutamine, 20 to 35 parts of serine, 5 to 25 parts of alanine, 2 to 20 parts of aspartic acid and 15 to 35 parts of phenylalanine; the composition can be used as an active ingredient to be prepared into different dosage forms such as a pigmentum, a spray, an ointment and a liniment, is applied to prevention of alopecia and promotion of hair growth, and has a remarkable treatment effect.

The invention discloses a low-foam acidic zinc plating additive and a preparation process thereof, and belongs to the technical field of electroplating additives, the additive comprises a low-foam softening agent and a water-based brightener, and the low-foam softening agent comprises the following raw materials in percentage by mass: 0.8-1.2% of polyethyleneimine, 0.03-0.06% of monododecyl phosphate potassium, 0.2-0.6% of water-soluble polyether amine and the balance of water. The water-based brightener is prepared from the following raw materials: 0.6 to 1.2 percent of 5-hydroxymethylfurfural, 0.2 to 0.4 percent of L-cysteine salt, 0.1 to 0.15 percent of 4-amino-2 (1H) pyrimidone, 0.05 to 0.1 percent of sodium salicylate, 1 to 1.5 percent of citric acid, 0.3 to 0.5 percent of alpha-ketoglutaric acid, 0.2 to 0.4 percent of erythorbic acid and the balance of water. The water-based formula is prepared by optimizing the components in the additive, the components are uniformly dispersed, the foam amount is low, and the plating quality is good.

The invention discloses application of copper-amino acid nano enzyme in preparation of anti-inflammatory drugs, and relates to the technical field of biomedical new materials, amino acids comprise glycine, arginine, histidine, threonine, phenylalanine and cysteine; the ratio of the amino acid to the copper ions is 1: (0.5-5), and the synthesis temperature of the copper-cysteine nano enzyme is 25-125 DEG C. The copper-amino acid nano-enzyme library established by the invention has efficient hydroxyl free radical, superoxide free radical and hydrogen peroxide scavenging activity; wherein the copper-cysteine nano-enzyme shows the highest enzymatic activity, and shows low toxicity and good biocompatibility in both the cell level and the animal level; meanwhile, the copper-cysteine nano-enzyme also shows anti-inflammatory activity and anti-oxidative stress activity, can remarkably improve cell inflammation and body inflammation, relieves and treats dextran sodium sulfate induced mouse ulcerative colitis, and can be further applied to preparation of drugs for treating inflammatory bowel diseases.

The invention provides application of wheat cysteine receptor kinase TaCRK25-1B and a coding gene thereof in regulation and control of stripe rust resistance of plants, and belongs to the technical field of plant genetic engineering. The TaCRK25-1B provided by the invention is subjected to induced expression of stripe rust infection in wheat, a VIGS technology instantaneous silencing experiment shows that the resistance of the wheat to stripe rust CYR31 is enhanced by silencing the TaCRK25-1B, the TaCRK25-1B is over-expressed in the wheat by a genetic transformation technology, the resistance of the wheat to stripe rust is weakened, and an RNAi interference plant infection pathogen experiment of the TaCRK25-1B created by an RNAi technology shows that the TaCRK25-1B has the advantages that the TaCRK25-1B can be used for expressing the stripe rust CYR31 in the wheat; the TACRK25-1B plays a negative regulation role in wheat stripe rust resistance. Therefore, the invention provides a new means for wheat stripe rust resistance and resistant wheat breeding.

The invention discloses a polypeptide-nano-selenium compound and application of a composition of the polypeptide-nano-selenium compound in tumor resistance. The compound is composed of nano-selenium and polypeptide with a specific amino acid sequence Cys-Phe-Leu-Gly-Arg-Glu-Gly-Lys-Trp-Gly-Tyr-Cys, the polypeptide and selenium atoms on the surface of the nano-selenium form coordinate bonds through cysteine residues at two ends, and the problem that the nano-selenium is prone to aggregation and inactivation is effectively solved. The preparation method comprises the following steps: reducing ascorbic acid to prepare nano-selenium, and modifying the polypeptide on the surface of the nano-selenium through a coordination reaction. Experiments show that the change rate of the particle size of the nano-selenium is less than 5% after the compound is stored for 3 months, and the stability is remarkably improved; and the inhibition rate on various tumor cells after 72 hours exceeds 80%. The compound provided by the invention is simple in preparation process and high in safety, can be used as an active component to prepare antitumor drugs in various dosage forms such as tablets, injections and the like, and provides a new effective means and thought for tumor treatment.

The invention discloses an enhanced Raman scattering substrate for chiral molecule detection and a preparation method, and relates to the technical field of spectral analysis and chiral recognition. Chiral cysteine is induced at the core of the gold nanorod to form a spiral chiral gold-silver alloy layer and then wraps the zirconium-based metal organic framework, the synthesized chiral gold rod (at) MOF material has excellent LPSR effect and chiral electromagnetic field, and the MOF layer on the surface can well adsorb molecules to be detected to enter a plasma hot spot area. The Raman substrate is excellent in SERS performance. According to the composite material, through the dual effects of molecular enrichment and electromagnetic enhancement, enantiomers are distinguished directly through SERS intensity, and labeling or catalytic conversion is not needed.

The invention relates to the technical field of gene engineering and enzyme engineering, in particular to a beta-glucosidase mutant with high catalytic activity and application of the beta-glucosidase mutant. The sequence of the beta-glucosidase mutant is obtained by carrying out any one of the following mutations on an amino acid sequence as shown in SEQ ID No.1: respectively mutating proline at the 95th site and arginine at the 178th site into cysteine; phenylalanine at the 98th site and arginine at the 178th site are respectively mutated into cysteine. The obtained mutants P95C / R178C and F98C / R178C have high enzyme activity, ginsenoside Rb1 can be converted into CK, the conversion efficiency is respectively improved by 83.52% and 105.79% compared with that of wild beta-glucosidase, and the industrial application of enzymatic conversion of rare ginsenoside CK is promoted.

The invention discloses a mannose modified liposome gel microsphere oral delivery system based on cations and application of the mannose modified liposome gel microsphere oral delivery system. The oral delivery system comprises a core layer and a wrapping layer, the core layer is mannose modified cationic liposome loaded with a mucous membrane adjuvant retinoic acid and an antigen, and the wrapping layer is sodium alginate gel vulcanized and modified by cysteine. The mannose modified cationic liposome is prepared by coupling mannose on the surface of the cationic liposome, and the cysteine modified sodium alginate gel is used for protecting antigens in the core layer from being eroded by gastric juice, enhancing the adhesiveness of a delivery system in the intestinal tract and prolonging the retention time of the delivery system in the intestinal tract; in addition, the R-MLip can be expanded and released under the environment that the pH of the intestinal tract is increased. The inside of the gel microsphere of the oral delivery system shows a regular net-shaped structure and has abundant holes and channels, and the oral delivery system shows a good prospect in the aspect of enhancing mucous membrane and systemic immunity and possibly becomes a potential substitute of a traditional attenuated live vaccine in the future.

There is provided a method of producing a hydrogel. A first polymer functionalized with a homocysteine thiolactone of formula I is reacted to open the ring and obtain a pendant thiol group, wherein any three of the R2 are H, and the remaining R2 is selected from H, C1-C4 branched or linear alkyl, methoxy, ethoxy, and halogen;. (I) The pendant thiol group of the first polymer are then crosslinked with a pendant vinyl group on a second polymer in the presence of a gel former to obtain the hydrogel.

The invention belongs to the technical field of agricultural fertilizers, and particularly relates to a high-efficiency yield-increasing liquid fertilizer containing enzymolysis nereis and a preparation method thereof.The method comprises the steps that the nereis is cleaned and smashed, subjected to freeze-thaw cycle pretreatment and then subjected to enzymolysis through a compound protease preparation containing protease and chitinase under the alkalescence condition, and the liquid fertilizer containing the enzymolysis nereis and the chitinase is obtained; carrying out solid-liquid separation on the obtained enzymatic hydrolysate to obtain enzymatic clam worm liquid; the preparation method comprises the following steps: mixing urea, a phosphorus-potassium fertilizer, trace elements, potassium fulvate and polyaspartic acid in a preparation tank, and then adding an N-carbamoyl-L-glutamic acid-chitosan grafted copolymer and selenocysteine-alginic acid nanoparticles to obtain a nutrient solution; and finally, mixing the enzymolysis nereis solution with the nutrient solution and the plant growth regulator to obtain a finished product. Active substances in the nereis are fully released through a biological enzymolysis technology, the prepared liquid fertilizer has the functions of nutrition supply, physiological regulation and soil improvement, crop growth can be remarkably promoted, the yield can be remarkably increased, and high-value utilization of marine biological resources is achieved.

The invention relates to the technical field of functional microbial preparations, in particular to a biological preparation for relieving intestinal discomfort caused by alcohol and a preparation method and application thereof.The main technical scheme is that the biological preparation is prepared from, by weight, 5-20 parts of bacillus coagulans, 10-30 parts of pediococcus pentosaceus, 5-10 parts of lactobacillus rhamnosus and 0-20 parts of saccharomycetes. 0-5 parts of bifidobacterium longum and 0-5 parts of lactococcus lactis. By constructing an alcohol metabolism-intestinal protection dual-function synergistic system, specific florae such as bacillus coagulans, pediococcus pentosaceus and lactobacillus rhamnosus are scientifically compatible with functional components such as inulin and L-cysteine, alcohol is efficiently metabolized, and a carbon source is generated; the technical problems of low metabolic efficiency, weak intestinal protection and serious gastric acid inactivation of a traditional product are comprehensively solved.

The invention relates to a preparation method of manganous-manganic oxide / graphite nano-enzyme for sensitive detection of L-cysteine, a green synthesis strategy is adopted, a mechanochemical method is combined to develop a novel Mn3O4 / graphite composite material which is low in cost, high in activity and easy to synthesize in macroscopic quantity, and the prepared product has relatively high catalytic activity and can be applied to the detection of L-cysteine. Compared with the prior art, the method has the advantages that oxidase-like activity is obviously improved, the Michaelis constant Km is 0.132, the maximum reaction rate Vmax is 0.998 * 10 <-7 > M <-1 > s, high-sensitivity and visual analysis and detection of L-Cys can be realized at normal temperature, the detection interval is 1-40 [mu] mol / L, and the detection limit is 0.361 [mu] mol / L.

The invention discloses a salicylic acid decarboxylase mutant and application of the salicylic acid decarboxylase mutant in degradation of salicylic acid. The mutant is obtained by carrying out site-specific modification on salicylic acid decarboxylase NahG, and specifically, valine at the 46th site, tyrosine at the 380th site and leucine at the 382nd site of an amino acid sequence shown in SEQ ID NO.2 are mutated into cysteine, phenylalanine and phenylalanine at the same time. The mutant shows remarkably improved catalytic efficiency, and salicylic acid can be efficiently and thoroughly decarboxylated and converted into catechol under mild conditions. The invention also provides a coding gene, a recombinant vector and an engineering bacterium of the mutant. The mutant not only can be used for efficient bioremediation of salicylic acid pollution, but also can effectively break through and accelerate a naphthalene catabolism pathway due to the characteristic of directionally generating catechol, and has important application value in the fields of environmental pollution abatement and biological catalysis.

The invention belongs to the technical field of functional condiments, and provides a functional minced garlic sauce based on fermentation engineering and a preparation method thereof.According to the functional minced garlic sauce based on fermentation engineering and the preparation method thereof, the design that a lactic acid fermentation minced garlic matrix is combined with a double-layer structure functional microcapsule dispersion phase is adopted, and an inner core layer is composed of a clathrate compound formed by gamma cyclodextrin and allicin; an outer shell is formed by compounding protein and high-methoxyl pectin under a specific pH condition and is subjected to calcium ion cross-linking stabilization, and an immobilized gamma-glutamyltransferase conversion and a lactobacillus plantarum and lactobacillus rhamnosus co-fermentation process are adopted; the microcapsule has the advantages that the content of S-allyl L-cysteine is larger than or equal to 220 mg / kg, the particle size D50 of the microcapsule is 5-10 micrometers, and the viable bacterium stability is good under the low-salt condition, the technical problems that allicin retention and stability of minced garlic seasoning products are insufficient, and functional ingredient enrichment and viable bacterium stability are difficult to consider under the low-salt condition are solved, and the technical effects that the content of S-allyl L-cysteine is larger than or equal to 220 mg / kg and the particle size D50 of the microcapsule is 5-10 micrometers are achieved. And the method has a wide industrial application value.

This invention relates to a modified titanium dioxide for matting polyester fibers and its preparation method. The modified titanium dioxide comprises a mesoporous titanium dioxide core and a cysteine ​​graft layer grafted into the pores of the mesoporous titanium dioxide. The mesoporous titanium dioxide core is prepared by evaporation-induced self-assembly using an alkenyl sulfonate surfactant as a liquid crystal template and tetraethyl or tetrabutyl titanate as the titanium source. Due to the self-polymerization reaction of the alkenyl sulfonate, the resulting polyalkenyl sulfonic acid compound reduces the crystallinity of the mesoporous titanium dioxide, thereby significantly reducing its photocatalytic activity. The mesoporous titanium dioxide is mixed with cysteine ​​and heated to graft cysteine ​​into its pores. The presence of cysteine ​​results in the modified titanium dioxide exhibiting both good matting properties and suppressed photocatalytic activity, preventing fiber structure damage from prolonged ultraviolet irradiation when applied to polyester fibers.

The invention discloses a preparation method of an antibacterial warm-keeping fabric, and relates to the technical field of textiles. When the antibacterial warm-keeping fabric is prepared, firstly, (E)-butyl-2-ene-1, 4-diamine, glyoxal, formaldehyde and butyric acid are used as raw materials to synthesize a polyimidazolium salt antibacterial agent, then the polyimidazolium salt antibacterial agent is copolymerized with polytetrahydrofuran ether glycol and diphenylmethane diisocyanate to prepare an antibacterial polyurethane spinning solution, and the antibacterial fabric is obtained through wet spinning and weaving. The preparation method comprises the following steps: reacting L-cysteine with 3-amino propyl triethoxy silane to prepare cysteamine acyl propyl triethoxy silane, reacting with formaldehyde and phosphorous acid to obtain flame-retardant modified silane, and further preparing a silicon dioxide solution from the flame-retardant modified silane and sol-gel such as methyltrimethoxysilane; finally, the antibacterial fabric is treated with a benzophenone solution and then soaked with a silicon dioxide solution, and the antibacterial thermal fabric is prepared through ultraviolet irradiation, standing gelation, aging and hexane washing. The prepared fabric has excellent antibacterial property, heat retention property and flame retardant property.

The invention belongs to the technical field of enzyme mutants, and discloses a mutant of lycopene cyclase and application of the mutant, glutamic acid at the 321 site of wild type lycopene cyclase which is derived from arabidopsis and has an amino acid sequence as shown in SEQ ID NO.1 is mutated into lysine, phenylalanine at the 319 site of the wild type lycopene cyclase is mutated into leucine, cysteine at the 323 site of the wild type lycopene cyclase is mutated into alanine, and the mutant of the lycopene cyclase is obtained. 1, and the lycopene cyclase mutant with the amino acid sequence as shown in SEQ ID NO. 2 is obtained. BTS1, CrtB and CrtI are integrated into a saccharomyces cerevisiae BY4741 strain, and a chassis strain ZA1 for stably producing alpha-carotene precursor lycopene is constructed; mutant expression plasmids are constructed, positive clone strains are screened out, and the epsilon-cyclization ability of mutant enzymes is remarkably higher than the beta-cyclization ability; the method comprises the following steps: by taking lycopene as a substrate, constructing an expression vector lipid droplet surrounding protein PET10; gene PAH1, DGA1 and Cat2 related to TAG synthesis and perilipid droplet protein PET10 are constructed on an expression vector and converted into ZA1, and when lycopene is used as a substrate, the efficiency of catalytic production of alpha-carotene is improved.

The invention discloses an ergothioneine-producing recombinant engineering bacterium as well as a construction method and application thereof, and belongs to the technical field of gene recombination fermentation. The method comprises the following steps: by taking escherichia coli as a starting bacterium, carrying out recombinant expression on a histidine trimethyl inner salt cysteine sulfoxide synthetase egt1 gene, an L-histidine methyltransferase egtD gene, a histidine trimethyl inner salt cysteine sulfoxide lyase egt2 gene, a methionine adenosine transferase metK gene, an adenylate kinase adK gene and an adenine phosphoribose transferase apt gene; on this basis, supply of precursor substances including histidine, cysteine and methionine is further improved through metabolic transformation, the yield of the finally obtained recombinant engineering bacterium for producing ergothioneine reaches 2.54 g / L after 48 h of shake-flask culture, the yield of a 5L fermentation tank reaches 18 g / L after further enlarged culture, the yield of ergothioneine is guaranteed while energy consumption and cost are reduced, and the method is suitable for industrial production. The method is suitable for practical popularization.

Provided a method for promoting growth of bacteria of the genus Bifidobacterium. The method for promoting growth of bacteria of the genus Bifidobacterium includes subjecting a milk culture medium containing one or more selected from the group consisting of cysteine, cystine, and a salt thereof to heat treatment and then culturing bacteria of the genus Bifidobacterium in the milk culture medium.

The present application relates to a kind of method and kit for detecting methylation cysteine total amount, belong to the field of biotechnology and analytical test.Utilize nucleic acid aptamer with high response to free Hcy, with moderate corresponding state Hcy to construct evanescent wave optical fiber sensor.Complementary strand and tHcy of fluorescently labeled are combined with the nucleic acid aptamer fixed on optical fiber with competition.Fluorescence signal drop value is positively correlated with tHcy concentration in serum.According to the percentage of fluorescence reduction, the tHcy concentration in serum is calculated.The present application detects tHcy only needs 1 microliter serum, after diluting 1000 times, detection is carried out, and the detection result is consistent with commercial enzyme cycle method.Compared with enzyme cycle method, the present application has the advantages of low price, optical fiber can be reused more than 30 times, detection speed is fast, fastest 5 minutes, does not need enzyme, equipment miniaturization, simple operation, etc., has excellent clinical application value.