675 results about "Cystine" patented technology

The invention discloses a fatty acid modified coronavirus antigen and application thereof, and belongs to the field of biological medicine. The fatty acid modified coronavirus antigen contains fatty acid modified N-terminal cysteine (Cys) and a coronavirus antigen, and can contain a connecting structural domain; the coronavirus antigen is a coronavirus spike protein (S protein) receptor binding domain (RBD). The fatty acid modified coronavirus S protein RBD can be self-polymerized into nanoparticles, and compared with the RBD which is not subjected to fatty acid modification, the antigen can induce faster and higher humoral immunity through injection immunity, can induce mucosal immunity and humoral immunity through respiratory tract atomization immunity, and is a candidate mucosal vaccine with potential medical value.

The invention belongs to the field of bioengineering, and particularly discloses a tryptophan synthetase mutant with improved enzymatic activity and application of the tryptophan synthetase mutant in production of L-cysteine. Compared with wild tryptophan synthetase from escherichia coli, the amino acid sequence of the tryptophan synthetase mutant has the advantages that a beta catalytic subunit has T69A, S143A, R219E and F280H site combined mutation. Researches show that the enzyme activity of the mutant is increased by 2.4 times compared with that of a wild type through enzyme activity determination and analysis of inducible expression and purification. The beneficial tryptophan synthetase mutant provided by the invention can efficiently biocatalyze L-serine and sodium hydrosulfide to synthesize L-cysteine, and has a better industrial application prospect.

The invention relates to the technical field of microbial genetic engineering, in particular to a method for improving cordycepin synthesized by saccharomyces cerevisiae and saccharomyces cerevisiae engineering bacteria. According to the invention, codon-optimized 2 '-carbonyl-3'-deoxyadenosine reductase gene and 3 '-adenosine monophosphate phosphohydrolase gene from cordyceps militaris are expressed by using plasmids, and then the plasmids are transformed into host cells to obtain the saccharomyces cerevisiae engineering bacteria. And inoculating a seed solution obtained by seed culture of the activated saccharomyces cerevisiae engineering bacteria into a fermentation culture medium containing a metabolic effector, and carrying out fermentation culture to synthesize cordycepin. Metabolic effectors (Cu < 2 + >, Fe < 2 + >, Mg < 2 + >, Zn < 2 + >, citric acid, cysteine, aspartic acid, glycine, VB1 and tea polyphenol) are added into a fermentation culture medium strain, and the variety and concentration of the metabolic effectors are optimized, so that the yield and synthesis efficiency of cordycepin are remarkably improved. By using the combination of the strain obtained by the invention and the optimal effector, the yield of cordycepin in a fermentation tank reaches 2.9 g / L.

The invention relates to the technical field of biology, and discloses a carbonyl reductase mutant and application thereof in enzymatic synthesis of chiral alcohol. The amino acid sequence as shown in SEQ ID NO.2 is subjected to mutation that 36th lysine is mutated into any one of aspartic acid, threonine and valine, or / and 125th histidine is mutated into any one of lysine, serine and leucine, or 170th histidine is mutated into any one of lysine, cysteine and leucine. The carbonyl reductase mutants, especially single-site mutants Mut-T75K, Mut-T75D and Mut-E216M and a combined mutant Mut-T75K-E216M, with activity improved to different extents compared with that of a wild type are obtained, have excellent relative enzyme activity, thermal stability and substrate tolerance, have relatively high activity and stability for various chiral alcohols, and can be used for preparing the carbonyl reductase mutants. The catalyst has the advantages of high catalytic activity, high thermal stability, strong substrate tolerance, easiness in fermentation and the like.

The invention relates to a plasma metabolite composition for auxiliary diagnosis of sub-clinical mastitis of dairy cows and application of the plasma metabolite composition. The plasma metabolite combination is a first combination and / or a second combination, and the first combination is composed of glyceryl monolinoleate, 2-methylthiophene, L-cystine, (S)-(+)-citramalic acid, 9-hydroxy-10, 12-octadecadienoic acid, 16-hydroxyhexadecanoic acid, tyrosine hydroxyproline, stearoyl serotonin and histamine; the first composition is composed of 4, 5-dimethyl-2, 4, 5-trimethyloxazole, 12, 13-epoxy octadecadienoic acid, 2-cyclotetradecene-1-ketone, 4 [alpha]-carboxyl-5 [alpha]-cholest-8-ene-3 [beta]-alcohol, N-arachidonyl dopamine d8, 9 (Z) and 11 (E)-conjugated linoleic acid, and the second composition is composed of 2, 5-dihydro-2, 4, 5-trimethyloxazole, 12, 13-epoxy octadecadienoic acid, 2-cyclotetradecene-1-ketone, 4 [alpha]-carboxyl-5 [alpha]-cholest-8-ene-3 [beta]-alcohol, N-arachidonyl dopamine A product prepared based on the plasma metabolite composition and used for auxiliary diagnosis of cow subclinical mastitis is simple in use method and high in accuracy, can be used for assisting a milk somatic cell number method to diagnose cow subclinical mastitis, and reduces the probability of false negative and false positive.

The invention provides pantoea agglomerans and application thereof, and belongs to the technical field of microorganisms, the strain is preserved in China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCC No.36122; the strain has very high selenium tolerance and transformation capacity, and can transform inorganic selenium (such as Se (IV)) with relatively high toxicity into organic selenium (such as selenomethionine and selenocystine) with low toxicity and zero-valent nano-selenium (Se0) in a culture medium containing sodium selenite. The pantoea agglomerans obtained by the invention has the characteristics of selenium-addictive microorganisms, and has potential application value in biotransformation of selenium, microbial synthesis of nano-selenium, and growth promotion and selenium enrichment of crops. The pantoea agglomerans can promote plant growth, a liquid fermentation process developed by the strain is utilized, the highest conversion rate of organic selenium can reach 92.5%, and the synthesis efficiency of nano-selenium reaches 88.3%. And development of organic selenium agricultural products is well facilitated.

The invention belongs to the technical field of preparation of fluorescent powder, and particularly relates to double-shell narrow-band red-light fluorescent powder as well as a preparation method and application thereof. The narrow-band red-light fluorescent powder is Mn < 4 + >-doped potassium fluosilicate fluorescent powder, and the narrow-band red-light fluorescent powder is coated with a potassium fluosilicate inner shell layer and a cystine outer shell layer. The preparation method comprises the following steps: mixing a cysteine solution with the narrow-band red-light fluorescent powder, stirring, centrifuging, and drying the precipitate obtained by centrifuging to obtain the double-shell narrow-band red-light fluorescent powder. The surface of the prepared fluorescent powder is provided with the Mn < 4 + >-free potassium fluosilicate inner shell layer and the outer hydrophobic cystine layer, the surface of the core narrow-band red-light fluorescent powder is covered with the double-shell structure, the water resistance and the light-emitting characteristic of the narrow-band red-light fluorescent powder can be remarkably improved, and the wide application prospect is achieved.

The invention relates to a carbon dioxide electrocatalytic reduction catalyst, in particular to an L-cysteine modified nano-silver electrocatalyst and application thereof, and belongs to the technical field of carbon dioxide emission reduction and resource utilization and electrocatalytic material synthesis. A preparation method of the L-cysteine modified nano-silver electrocatalyst comprises the following steps: S1, dissolving silver nitrate in water to obtain a 0.05-100mM silver nitrate solution, adding the silver nitrate solution into ethylene glycol, and uniformly stirring; the volume ratio of the silver nitrate solution to the ethylene glycol is 1: (2-20); s2, L-cysteine is added into the mixed solution, microwave heating is performed after uniform stirring, obtained solids are centrifugally washed at least three times with ethyl alcohol and ultrapure water respectively, and the solids are dried in a vacuum drying box to obtain nano-silver particles; the molar ratio of the silver element to the L-cysteine is 1: (0.01-10). By improving the adsorption capacity of the electrocatalyst on active substances, high selectivity and high stability of the product CO in a CO2 in-situ conversion system are realized.

The present invention relates to: a temperature-sensitive hydrogel for cancer treatment; a photothermal composition comprising the hydrogel as an active ingredient; and a preparation method for the temperature-sensitive hydrogel for cancer treatment. The temperature-sensitive hydrogel of the present invention includes gold nanostars as active ingredients, and thus can generate heat by light irradiation, thereby exhibiting a photothermal therapy effect. In addition, the hydrogel temperature increases so that the release of nitric oxide (NO) from S-nitrosocysteine can be induced. In addition, the temperature-sensitive hydrogel of the present invention includes S-nitrosocysteine as an active ingredient so that, upon a temperature rise due to a photothermal reaction, the penetration of drugs into a tumor site can be improved by the release of NO, and at the same time, apoptosis of cancer cells can be directly caused; and includes an immunotherapy agent as an active ingredient so that tumor size can be effectively suppressed even with the passage of time. Therefore, as a material that enables complex treatment combined with photothermal therapy and immunotherapy, the temperature-sensitive hydrogel of the present invention having the aforementioned effect can be usefully utilized in the field of medicine for cancer treatment.

The invention discloses a polypeptide with a whitening effect and a preparation method and application thereof.The polypeptide is obtained from hydrolyzed protein of babylonia areolata, the amino acid sequence of the polypeptide is cysteine-arginine-proline-threonine-cysteine-serine-arginine-leucine-alanine-cysteine, and the amino acid sequence of the polypeptide is cysteine-arginine-proline-threonine-cysteine-serine-arginine-leucine-alanine. The compound can obviously inhibit the generation of melanin in cells and the activity of tyrosinase in vitro, has the characteristics of low toxicity, low irritation, good stability, safety and high efficiency, and can be applied to whitening cosmetics.

The invention discloses a method for efficiently producing ergothioneine by metabolic engineering modified escherichia coli and application, and belongs to the technical field of biology. By adopting the recombinant escherichia coli EGT-1-B * provided by the invention, glucose can be converted into ergothioneine; therefore, the raw materials are cheap and easy to obtain, additives and heavy metals which are harmful to human health are avoided, a good foundation is laid for later product purification, and the requirements of commercial application can be met. Furthermore, genes related to metabolism of histidine, methionine, cysteine and S-adenosylmethionine are further overexpressed in the recombinant escherichia coli EGT-1-B *, so that the content of precursor amino acid synthesized by the ergothioneine is increased, and meanwhile, after the gene yqaB is knocked out, the yield of the ergothioneine is further increased; the utilization rate of glucose to ergothioneine can be further improved, and the yield of ergothioneine can reach 140.29 mg / L.

The invention discloses a gelator and a preparation method and application thereof, the structural formula of the gelator is # imgabs0 #, R1 is a side chain group connected to an amino acid central carbon atom except an amino group, a carboxyl group and a hydrogen atom; the amino acid is selected from one of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, selenocysteine and pyrrole lysine; the amino acid is selected from one of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, selenocysteine and pyrrole lysine; r2 is alkyl with the carbon atom number of 16 to 19; and R3 is 9-fluorenyl methoxy carbonyl group or t-butyloxycarbonyl group. The gelator has a hydrophobic long alkyl tail chain, can spontaneously gather and assemble into a three-dimensional network structure through hydrogen bonds, pi-pi interaction and hydrophobic force, and fixes an oil phase in an oil solvent or an oil-water mixture in an effective manner to form high-strength gel.

The invention includes compositions comprising at least one chimeric autoantibody receptor (CAAR) specific for an anti-phospholipase A2 receptor (PLA2R) autoantibody-based B cell receptor (BCR), polynucleotides encoding the CAAR, vectors comprising a polynucleotide encoding the CAAR, and recombinant cells (e.g., T cells) comprising the CAAR, wherein the CAAR comprises a PLA2R autoantigen comprising an extended cysteine rich (eCysR) domain comprising (a) a PLA2R N-terminal peptide and a cysteine rich (CysR) domain, and (b) a C-type lectin domain 7 (CTLD7). The invention also includes methods of making a genetically modified cell, e.g., a genetically modified T cell, expressing a PLA2R-CAAR wherein the expressed CAAR comprises a PLA2R autoantigen comprising an extended cysteine rich (eCysR) domain comprising (a) a PLA2R N-terminal peptide and a cysteine rich (CysR) domain, and (b) a C-type lectin domain 7 (CTLD7).

The invention discloses a bran fermented biological feed and a preparation method thereof, and belongs to the technical field of feeds. The bran fermented biological feed is prepared by uniformly mixing and fermenting the following raw materials: wheat bran, corn flour, soybean meal, calcium hydrogen phosphate, sodium chloride, an enzyme preparation, a water retention setting agent, a mildew preventive and water, wherein the enzyme preparation is prepared from lactobacillus plantarum, bacillus subtilis and saccharomycetes; the mildew preventive is prepared by the following steps: reacting chitosan oligosaccharide with propiolic acid to obtain modified chitosan oligosaccharide, reacting L-cystine with ethyl azidoacetate to obtain an azide compound, and finally reacting the modified chitosan oligosaccharide with the azide compound. The prepared bran fermented biological feed has an excellent mildew-proof effect and a low pulverization rate, and storage and transportation of the feed are facilitated.

The invention discloses a method for detecting L-cysteine in serum based on N, S co-doped carbon nanodots, and belongs to the field of analysis and detection. The method comprises the following steps: (1) preparing carbon dots by taking beta-mercaptoethylamine and p-phenylenediamine as precursors; (2) after Fe < 3 + > is added into the carbon dot solution, a carbon dot fluorescence quenching phenomenon occurs, and a carbon dot-Fe < 3 + > mixed system is obtained; then adding L-cysteine into the carbon dot-Fe < 3 + > mixed system to gradually recover the fluorescence of the system; and (3) constructing a linear relationship between the concentration of the L-cysteine and the fluorescence recovery degree to obtain the quantitative detection model for the L-cysteine in the serum sample. According to the method, the carbon dots are prepared by taking beta-mercaptoethylamine and p-phenylenediamine as precursors for the first time, quantitative detection of L-cysteine is realized, and the method is low in cost, high in sensitivity, suitable for field rapid detection and relatively high in practical value and popularization prospect.

The invention relates to a preparation method of a high-temperature proton exchange membrane, in particular to a preparation method of a phosphoric acid / cystine functionalized MXene / polybenzimidazole composite high-temperature proton exchange membrane for a high-temperature fuel cell. The invention aims to solve the problem of insufficient oxidation resistance of the existing fuel cell proton exchange membrane. The method comprises the following steps: 1, preparing polybenzimidazole; (2) preparing cystine functionalized MXene; and 3, preparing a cystine functionalized MXenen and OPBI compounded proton exchange membrane, and then dipping in a phosphoric acid solution. According to the application of the cystine functionalized MXene / polybenzimidazole composite membrane for the high-temperature fuel cell in HT-PEM, the conductivity and oxidation resistance of a proton exchange membrane are improved, a basis is provided for developing novel efficient HT-PEM, and the cystine functionalized MXene / polybenzimidazole composite membrane is applied to the technical field of proton exchange membrane fuel cells.

The invention relates to the technical field of biology, and discloses a recombinant carbonyl reductase mutant and application thereof in synthesis of chiral alcohol. According to the invention, the 36th-site lysine is mutated into any one of aspartic acid, threonine and valine, or / and the 125th-site histidine is mutated into any one of lysine, serine and leucine, or / and the 170th-site histidine is mutated into any one of lysine, cysteine and leucine; the carbonyl reductase mutants, especially single-site mutants Mut-K36D and Mut-H125K and a combined mutant Mut-K36D-H125K, with activity improved to different extents compared with that of a wild type are obtained, have excellent thermal stability and relative enzyme activity, have relatively high activity and stability aiming at various chiral alcohols, and can be used for preparing the carbonyl reductase. The method has the advantages of high catalytic activity, high enzyme expression quantity, easiness in fermentation and the like.

In the first aspect, the present disclosure provides a Lactoferrin polypeptide fragment, where the Lactoferrin polypeptide fragment has an amino acid sequence shown in SEQ ID NO: 1. In the second aspect, the present disclosure provides a preparation method of the Lactoferrin polypeptide fragment, including: protecting amino acids using a 9-fluorenylmethoxycarbonyl (Fmoc) protecting group, coupling the amino acids with a P-hydroxymethylphenoxymethyl polyethylene resin (HMP resin) in an order of cysteine, alanine, leucine, cysteine, glutamate, threonine, asparagine, aspartate, asparagine, phenylalanine, leucine, leucine, asparagine, and lysine, and separating the HMP resin to obtain a target Lactoferrin polypeptide fragment. In the third aspect, the present disclosure further provides an anti-Lactoferrin antibody prepared using the Lactoferrin polypeptide fragment, and use of the Lactoferrin polypeptide fragment in preparation of an anti-Lactoferrin flow cytometric antibody and in preparation of a Lactoferrin detection product.

The invention belongs to the technical field of biology, and particularly relates to a CHO cell suspension culture medium as well as a preparation method and application thereof. The culture medium comprises amino acids, vitamins, inorganic salts, trace elements, carbohydrates and other molecular compounds; the amino acids comprise glycine, L-alanine, L-arginine, L-asparagine, L-aspartic acid, L-cysteine, L-cystine, L-glutamic acid, L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine and L-valine. The culture medium provided by the invention can meet the high-density suspension culture of various CHO cells, can improve the production efficiency and reduce the production cost, and has wide application prospects and values. The culture medium provided by the invention overcomes the defects of the existing culture medium with determined chemical components, and provides more choices for the culture medium with determined chemical components in China.

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 a method for improving moso bamboo cellulase hydrolysis conversion efficiency through amino acid-based deep eutectic solvent pretreatment, and belongs to the technical field of biomass recycling. The method comprises the following steps: mixing an L-cysteine solid and a formic acid solution, performing water bath heating to prepare an acidic eutectic solvent, performing microwave-assisted eutectic solvent pretreatment on moso bamboos, and performing filtration separation and enzymolysis; wherein the molar ratio of the L-cysteine to the formic acid is 1: (4-5). A deep eutectic solvent formed by formic acid and cysteine has a strong hydrogen bond network and an acid environment, beta-O-4 ether bonds in lignin are promoted to be broken, sulfydryl of cysteine participates in nucleophilic attack, a lignin-carbohydrate complex is further destroyed, formic acid can hydrolyze acetyl and glucosidic bonds in hemicellulose, and the lignin-carbohydrate complex is further destroyed. And degrading into an oligomer or monosaccharide. The phyllostachys pubescens components are efficiently separated, the cellulose enzymolysis saccharification capacity is improved, and effective utilization of all the phyllostachys pubescens components is facilitated.

The invention provides a probiotic mixed fermentation method for enhancing a synergistic effect. Lactobacillus plantarum, bifidobacterium longum and clostridium tyrobutyricum are inoculated according to a volume ratio, and a pH-triggered two-stage fermentation process is adopted: the first stage is micro-aerobic to drive lactic acid bacteria to quickly produce acid, and the second stage is anaerobic to directionally improve butyric acid synthesis by pulse feeding of inulin-cysteine sustained-release particles. Physical isolation of flora is realized by using a double-layer gradient carrier, lactic acid bacteria are immobilized by sodium alginate-gelatin gel on the outer layer to form an acid barrier, and bifidobacterium and butyric acid producing bacteria are co-immobilized by chitosan microspheres on the inner layer to construct an anaerobic microenvironment. The technology breaks through the competitive inhibition bottleneck of multi-strain fermentation, the total number of viable bacteria is increased by 150% compared with a traditional technology, the yield of butyric acid is increased by 355%, and the technology is suitable for large-scale production of functional food and pharmaceutical preparations.

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 a gallium-68 / lutetium-177 / terbium-161 labeled cysteine modified FAPI complex as well as a preparation method and application thereof, and belongs to the technical field of cysteine modified complexes. According to the 68Ga / 177Lu / 161Tb-FAP-Cys complex and the preparation method of the 68Ga / 177Lu / 161Tb-FAP-Cys complex, the 68Ga / 177Lu / 161Tb-FAP-Cys complex is obtained through two steps of synthesis of a ligand FAP-Cys and preparation of the 68Ga / 177Lu / 161Tb-FAP-Cys. The complex is simple and convenient to prepare, high in radiochemical purity, good in stability, high in tumor uptake and high in target-to-cost ratio in a fibroblast activation protein (FAP) high-expression tumor model, can specifically target a tumor site, and is a novel tumor radiopharmaceutical with clinical application value.

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 particularly relates to a diphtheria toxin antigen modified by fatty acid and application thereof, and belongs to the field of biological medicine, in the diphtheria toxin antigen modified by fatty acid, the fatty acid modification comprises N-terminal cysteine (Cys) modified by fatty acid, the N-terminal Cys modified by fatty acid is characterized in that sulfydryl containing Cys is modified by diacylglycerol and / or alpha amino is modified by fatty acyl. Compared with the existing diphtheria toxin protein antigen, the fatty acid modified diphtheria toxin antigen not only has faster induction and higher immune protection effect than the conventional intramuscular injection induction of the existing diphtheria toxin antigen, but also can induce respiratory tract mucosa immunity, and provides a basis for blocking diphtheria infection and diffusion propagation and providing a vaccine for immunoprophylaxis.

The invention discloses a Cu (I)-Cys nano material of a bionic plant ethylene receptor protein, an MXene / Cu (I)-Cys nano composite material obtained by compounding the Cu (I)-Cys nano material with MXene, and preparation and application of the MXene / Cu (I)-Cys nano composite material for a wearable sensor, and belongs to the technical field of ethylene sensors. The Cu (I)-Cys nano material provided by the invention is a copper ion-cysteine dimeric complex and is obtained by dimerization of L-cysteine through sulfydryl and chelating of copper ions, and a coordination compound (Cu (I)-Cys) of Cu < + > and L-cysteine can be obtained by regulating the molar ratio of the copper ions to cysteine to be 0.8: 4. The material provided by the invention simulates plant ethylene receptor protein, is low in cost, simple to prepare and high in biocompatibility, can be applied to ethylene room temperature detection, and realizes that the lowest detection concentration reaches 50ppb and the lowest detection limit is 0.043 ppm.

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 discloses a method for detecting homocysteine by a nano-pore sensor based on silver-sulfur polymerization, which comprises the following steps: pretreating a solution containing the homocysteine by 4-dimethylamino cinnamyl aldehyde, and then putting a sensor with a cylindrical nano-pore structure into the solution containing the homocysteine to carry out polymerization reaction; establishing a linear equation of the ratio of the conductivity before and after the polymerization reaction and the concentration of the homocysteine, and calculating the concentration of the homocysteine in the liquid to be detected through the linear equation. The liquid to be detected contains homocysteine and cysteine, and is pretreated by 4-dimethyl amino cinnamyl aldehyde before detection; and an Ag (I) probe is modified in a cylindrical nanopore channel of the sensor. According to the method, a special pretreatment method is utilized to cooperate with a constructed functional probe and a special nanopore structure, and current signal change is amplified based on silver-sulfur polymerization reaction, so that rapid and accurate detection of Hcy is realized.

The invention provides a method for reducing acetic acid in a succinic acid fermentation process, and belongs to the technical field of fermentation. In the step of fermentation culture, a fermentation aid is fed in a fermentation culture process, specifically, when fermentation is performed for 10h, a fermentation aid I is fed into a fermentation culture tank at the feeding speed of 0.07-0.09 ml / h / L until fermentation is finished; when the fermentation is performed for 24 hours, feeding a fermentation aid II into the fermentation culture tank at the feeding speed of 0.12-0.14 ml / h / L until the fermentation is finished; the fermentation aid I comprises cobalt chloride hexahydrate, zinc sulfate heptahydrate, folic acid and biotin; the fermentation auxiliary agent II comprises nicotinamide, cysteine and tyrosine; the content of the fermentation culture solution prepared by the method disclosed by the invention is as high as 59.1-60.4 g / L, the content of acetic acid is as low as 0.30-0.65 g / L, and the content of malic acid is 0.20-0.23 g / L.