272 results about "Homoserine" patented technology

An amino acid such as threonine, homoserine, isoleucine, lysine, valine and tryptophan is produced using a bacterium belonging to the genus Escherichia which has been constructed from sucorse non-assimilative strain belonging to the genus Escherichia and which harbors sucrose non-PTS (phosphoenol pyruvate-dependent sucrose-6-phosphotransferase system) genes and has an ability to produce the amino acid.

L-Methionine is produced by culturing a microorganism which is deficient in repressor of L-methionine biosynthesis system and/or enhanced intracellular homoserine transsuccinylase activity is cultured in a medium so that L-methionine should be produced and accumulated in the medium, and collecting the L-methionine from the medium. The microorganism preferably further exhibits reduced intracellular S-adenosylmethionine synthetase activity, L-threonine auxotrophy, enhanced intracellular cystathionine γ-synthase activity and enhanced intracellular aspartokinase-homoserine dehydrogenase II activity. The present invention enables breeding of L-methionine-producing bacteria, and L-methionine production by fermentation.

The present invention relates to the use of recombinant homoserine transsuccinylase enzymes with altered feedback sensitivity (MetA*) and possibly recombinant S-adenosyl methionine synthetase enzymes with reduced activity (MetK*) for the production of methionine, its precursors or derivatives thereof.

The present invention relates to a plant, which is resistant to a pathogen of viral, bacterial, fungal or oomycete origin, wherein the plant has an increased homoserine level as compared to a plant that is not resistant to the said pathogen, in particular organisms of the phylum Oomycota. The invention further relates to a method for obtaining a plant, which is resistant to a pathogen of viral, bacterial, fungal or oomycete origin, comprising increasing the endogenous homoserine level in the plant.

A composition comprising an amphoteric or pseudo-amphoteric agent and a polyhydroxy alpha hydroxyacid existing as a free acid, lactone, or salt, and isomeric or non-isomeric forms thereof is provided. The amphoteric or pseudo-amphoteric agent can be selected from amino acids, dipeptides, aminoaldonic acid, aminouronic acid, lauryl aminoproplyglycine, aminoaldaric acid, neuraminic acid desulfated heparin, deacetylated hyaluronic acid, hyalobiuronic acid, chondrosine, deacetylated chondroitin, creatine, creatinine, hydroxyproline, homocysteine, homocystine, homoserine, ornithine, citrulline, phosphatidylserine, and sphingomyelin. The composition may contain other additives, including cosmetic or pharmaceutical agents for topical treatment of dermatological disorders.

Disclosed is a strain of Escherichia sp., capable of producing O-acetyl homoserine in high yield, with the introduction and enhancement therein of the activity of: homoserine acetyl transferase, aspartokinase and homoserine dehydrogenase; and at least one enzyme selected from a group consisting of phosphoenolpyruvate carboxylase, aspartate aminotransferase and aspartate semi-aldehyde dehydrogenase. Also, a method of producing O-acetyl homoserine using the strain is provided.

The invention concerns a homoserine transsuccinylase having at least one mutation compared to a wild-type homoserine transsuccinylase and reduced sensitivity towards a L-methionine or SAM, compared to the wild-type enzyme. The latter comprises an amino acid sequence including a partial AspGlyXaaXaaXaaThrGlyAlaPro sequence between position 90 and position 115 and a partial TyrGlnXaaThrPro sequence between position 285 and position 310, position 1 of the amino acid sequence corresponding to the initial methionine. The invention is characterized in that the mutation is a substitution of the aspartate in the partial AspGlyXaaXaaXaaThrGlyAlaPro sequence, or a substitution of the tyrosine in the partial TyrGlnXaaThrPro sequence.

The invention belongs to the field of medicinal chemistry, and discloses N-acyl-homoserine lactones substituted by benzo-heterocycle with bacterial quorum sensing inhibitory activity and a synthetic method and application thereof. The preparation method is simple, the conditions are mild and the yield is high. In vitro activity test results show that the N-acyl-homoserine lactones substituted by benzo-heterocycle can have an obvious inhibiting effect on a pseudomonas aeruginosa LAS system and a PQS system and can be applied to preparation of anti-bacterial quorum sensing and antimicrobial synergists and antibacterial or antitumor drugs. The chemical general molecular formula of the N-acyl-homoserine lactones substituted by benzo-heterocycle is as follows (please see the specification for the formula).

The invention discloses acyl-homoserine lactone degrading bacteria and application of the acyl-homoserine lactone degrading bacteria in disease control. The degrading bacteria are Acinetobacter schindleri and particularly refer to an acinetobacter strain XJ-10, the strain is collected in the China Center for Type Culture Collection on 2nd, November, 2017, and the collection number is CCTCC NO:M2017650. The strain can degrade quorum sensing signal molecules, is used for unique carbon source growth, and has a remarkable and rapid degradation effect on the AHLs quorum sensing signal molecules. Thus, microbial quorum sensing communication can be blocked through degradation of the quorum sensing signal molecules, expression of pathogenic factors of pathogenic bacteria is restrained, the purposeof disease control is achieved, and great application potential is achieved in the aspect of controlling the harm of pathogenic bacteria depending on AHLs mediated pathopoiesis. The problem of abuseof chemical pesticide can be solved, and meanwhile a novel strategy is provided for biologically controlling phytopathogen harm.

The invention discloses a heat-resisting N-acyl homoserine lactonase AiiA-AIO6 with high specific activity as well as a coding gene and application thereof. A protein provided by the invention is (a) or (b): the protein (a) is composed of amino acid sequences shown as a sequence 1 in a sequence table; the protein (b) is obtained through substituting and/or lacking and/or adding one or more amino acid residues of amino acid sequences shown as the sequence 1, has the activity of the N-acyl homoserine lactonase and is derived from the sequence 1. The AiiA-AIO6 protein provided by the invention is a novel N-acyl homoserine lactonase and the N-acyl homoserine lactonase is heat-resisting, has high specific activity, higher protease resistance and better capability of degrading each substrate and can be used as a novel bio-control enzyme preparation.

The invention discloses an examination method of aquatic product disease germ community induce signal member and its special-purpose reagent box. The method including carrying on the following experiment of the received test fungus: 1) adds X-Gal or ONPG on the plate with the root cancer farming bacillus together streak cultivation, observes whether demonstrates the blue color; 2) with the purple bacillus CV026 on the identical plate streak cultivation, observes whether demonstrates the purple color; 3) puts the received test fungus score inoculate on the LB plate which contains 500nM N-acylation homoserine lactone cultivated, observes whether demonstrated the purple discoloration will be shallow or removes; 4) draws a line together with Esc.coli pSB403 on the plate cultivated, observes whether shines; in above experiment, if at least an experiment demonstrates the masculine gender, then the received test fungus produces the N- acylation homoserine lactone. The invention method has high accurate rate, have no false negative phenomenon, easy to qualitative and quantitative analysis, operation simple, cost low, rapid to obtain the result, suits the large-scale high efficiency examination.

The object of the present invention is to provide a method for efficiently producing vinegar that contains a higher concentration of acetic acid, wherein a gene involved in the acetic acid fermentation ability is obtained, the acetic acid fermentation ability of an acetic acid bacterium is improved by reducing or deleting the function of the protein encoded by the gene. An acetic acid bacterium with a remarkably improved acetic acid fermentation ability was obtained by obtaining genes encoding an acyl homoserine lactone synthase and an acyl homoserine lactone receptor-type transcription factor that are involved in the quorum-sensing system in the acetic acid bacterium, and modifying the genes so as to reduce or delete the function of the quorum-sensing system. Further provided is a method for more efficiently producing vinegar containing a higher concentration of acetic acid by using the acetic acid bacterium.

The invention discloses a method for measuring homocysteine concentration. The method comprises the following steps of: placing a sample to be measured into an enzymatic circular reaction system, performing reaction shown as formulas 1 to 3, measuring and calculating the production rate of ammonia produced in the enzymatic circular reaction system so as to obtain the content of homocysteine in the sample to be measured; and the enzymatic circular reaction system comprises methionine synthase, methionine gama-lyase, O-acetyl homoserine aminocarboxypropyl transferase, 5-methyltetrahydrofolate or salt of the 5-methyltetrahydrofolate, and O-acetyl-L-homoserine. The invention also discloses a corresponding measuring reagent. The invention provides a novel homocysteine enzymological measuring method and a measuring reagent. The method does not need any special instrument, is easy and convenient to operate, has high sensitivity, is low in cost, can realize the clinical, quick and high-flow sample detection, ensures that the homocysteine possibly becomes the clinical conventional detection item, and has high scientific and economic value. The formulas 1 to 3 are shown in the specifications.

The present invention provides compounds and methods for modulation of the quorum sensing of bacteria. In an embodiment, the compounds of the present invention are able to act as replacements for naturally occurring bacterial quorum sensing ligands in a ligand-protein binding system; that is, they imitate the effect of natural ligands and produce an agonistic effect. In another embodiment, the compounds of the present invention are able to act in a manner which disturbs or inhibits the naturally occurring ligand-protein binding system in quorum sensing bacteria; that is, they produce an antagonistic effect. The compounds of the present invention comprise N-acylated-homoserine lactones (AHLs) comprised of a wide range of acyl groups.

A preparation method for D-asparagine and D-homoserine comprises the following steps: a, DL-aspartic acid methyl ester is taken as raw material, L-DBTA as resolving agent, water as solvent to carry through resolution reaction for 0.5-5 hours at 40-95 DEG C so as to get D-aspartic acid methyl ester-L-DBTA salt; b, the D-aspartic acid methyl ester-L-DBTA salt is stirred and hydrolyzed for 2-4 hours at room temperature in the presence of alkali to get D-aspartate-beta-methyl ester; c, the D-aspartate-beta-methyl ester is ammonolyzed in a solvent with ammonia gas, ammonia or liquid ammonia to get the D-asparagine; d, the D-aspartate-beta-methyl ester is deoxidized with reductant for 1-10 hours at 0-80 DEG C, neutralized with acid and then concentrated and processed through hydrogen or sodium cation exchange resin to get the D-homoserine. The invention provides a technology which uses cheap DL-aspartate to prepare D-asparagine and D-homoserine through esterification, resolving, ammonolysis, deoxidizing and other processes, thereby laying a solid foundation for the industrial production of two important D-type amino acids.

The invention discloses construction and applications of a corynebacterium glutamicum mutant strain for producing L-homoserine, and belongs to the technical field of fermentation engineering. Corynebacterium glutamicum ATCC 13032 is taken as a starting strain to knock out regulatory protein McbR, homoserine kinase, transport protein MetD, phosphoenolpyruvate carboxykinase; the expression of isocitrate dehydrogenase is down regulated; transport protein BrnFE, aspartic semialdehyde dehydrogenase and homoserine dehydrogenase are overexpressed; and the expression of aspartate kinase, pyruvate carboxylase and the aspartate kinase I derived from escherichia coli are enhanced. Shake flask culture can be performed on the mutant strain for 48 h, and the yield of L-homoserine can reach 8.8 g/L.

Screening assays that allow for the identification of agents that increase acyl homoserine lactone (AHL) acylase expression and/or AHL acylase activity in γ-proteobacteria such as Pseudomonas aeruginosa. Such agents are useful, for example, for inhibiting quorum sensing activity of such bacteria by increasing degradation of long chain, but not short chain, AHLs and, therefore, can be useful for treating infections by such bacteria.

The present invention concerns a method for the preparation of 2,4-dihydroxybutyric acid from homoserine comprising a first step of conversion of the primary amino group of homoserine to a carbonyl group to obtain 2-oxo-4-hydroxybutyrate, and a second step of reduction of the obtained 2-oxo-4-hydroxybutyrate (OHB) to 2,4-dihydroxybutyrate