281 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.

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.

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 a microorganism producing L-methionine precursor, O-acetylhomoserine, and a method of producing L-methionine precursor using the microorganism.

A bioactive food complex product, method for preparing a bioactive food complex product and method for controlling disease using probiotics and quorum sensing inhibitors such as inhibitory furanones and other bioactive compounds included in both the continuous and dispersed phases of a bioactive food complex product. The product is comprised of a solids-in-oil or an oil-in-solids emulsion forming a first emulsion that is itself emulsified in polymer forming oil-in-polymer or solids-in-polymer emulsion complex. The bioactive complex is formed of two emulsions with the first emulsion comprising the dispersed phase and a hydrocolloid polymer serving as the continuous phase. The second emulsion complex is then crosslinked to form a physically stable matrix. The bioactive food complex or the first emulsion of the bioactive food complex then serve to deliver different bioactive components including probiotic bacteria and quorum sensing inhibitor molecules to the digestive tract and environment of animals such as shrimp or fish or other livestock raised commercially to effectively control bacterial disease by a novel combination of mechanism including: competitive exclusion, direct inhibit, digestion of cell-to-cell signaling molecules and direct inhibition of homoserine lactone and (acyl) homoserine lactone regulated processes of pathogenic bacteria. Thus, effective disease prevention and control is accomplished through the novel combined delivery and use of probiotic bacteria and quorum sensing inhibitory furanones.

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 method of cleaning or protecting surfaces by treatment with compositions comprising N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL) blocking compounds and / or N-butyryl-L-homoserine lactone (BHL) analogs, either in combination or separately.

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.

The invention belongs to the technical field of sewage treatment and relates to a method for enhancing aerobiotic ammonia oxidizing bacterium (AOB) gathering through N-acylated homoserine lactone (AHLs) compounds. The method includes the specific steps that AHLs signal molecules with the specific variety and the specific concentration are added to a reactor containing AOB activated sludge, under the condition that a sufficient nitrogen source and oxygen are provided, a quorum-sensing system is enhanced, aerobiotic ammonia oxidizing bacterium gathering growth is promoted, and biological membranes or granular sludge is obtained. According to the method, the AOB physiology is adjusted and controlled on the aspect of the signal molecules, AOB gathering growth is enhanced, rapid and efficient enrichment of AOB is achieved, and the AOB is fixed in a qualified sense, so that losses are reduced, and time needed for AOB enrichment is shortened. A new thought is provided for rapid AOB enrichment through the method, the method is expected to be used for the biological nitrogen removal process, and important significance is provided for efficient and stable operation of the ammonia-nitrogen wastewater biological treatment process.

This invention relates to a nucleic acid fragment encoding a plant 5-methyltetra-hydropteroyltriglutamate-homocysteine methyltransferase or methionine synthase. The invention also includes chimeric genes, a first encoding a plant methionine synthase (MS) gene, a second encoding a plant cystathionine γ-synthase (CS) gene, a third encoding feedback-insensitive aspartokinase (AK) or bifunctional feedback-insensitive aspartokinase-homoserine dehydrogenase (AK-HDH), which is operably linked to a plant chloroplast transit sequence, and a fourth encoding a methionine-rich protein, all operably linked to plant seed-specific regulatory sequences. Methods for their use to produce increased levels of methionine in the seeds of transformed plants are provided.

The present invention provides compositions and methods for modulating the communication and virulence of quorum sensing bacteria. In various exemplary embodiments, the invention provides a combinatorial library of quorum sensing compounds including synthetic analogs of naturally occurring and non-naturally occurring acyl-homoserine lactone (AHL) analogs, and methods of synthesizing and using these compounds.

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 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.

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 provides a quorum sensing quenching bacteria preparation method, a MBR membrane pollution prevention and control method, and a MBR membrane pollution prevention and control apparatus. The preparation method comprises: preparing an alternative strain having N-hexanoyl-homoserine lactone AHL decomposition and utilization capability from active sludge or sewage sampled from a sewage treatment plant; verifying the quorum sensing quenching ability of the alternative strain to screen quorum sensing quenching bacteria; and verifying the anti-bio-film ability of the quorum sensing quenching bacteria to obtain the effective quorum sensing quenching bacteria. According to the present invention, the prepared quorum sensing quenching bacteria uses the pollutants in the sewage as the nutrition to decompose other microorganisms during the growth process to generate the signal molecules, such that the concentration of the AHL signal molecules produced by other microorganisms in the membrane pool cannot achieve the concentration threshold required by the quorum sensing and the signal loop conduction cannot be formed so as to inhibit the bio-film formation of the membrane pool microorganisms on the MBR membrane assembly surface and achieve the effects of pollution prevention and energy consumption saving.

Amino acids such as threonine, homoserine, isoleucine, lysine, valine and tryptophan are produced using a bacterium belonging to the genus Escherichia which has been constructed from a sucrose non-assimilative strain belonging to the genus Escherichia and which harbors sucrose non-PTS or PTS genes and has an ability to produce the amino acid.

The invention relates to an environmentally-friendly method for synthesizing selenomethionine. The method comprises the following steps of: reducing alpha-amido-protected aspartate beta-alkyl grease into alpha-amido-protected homoserine, then carrying out acid catalysis for ring closing to obtain inner grease of the homoserine, then reacting with metal selenide to generate homocystine selenide, obtaining the alpha-amido-protected homoserine, and finally eliminating protection and obtaining a selenomethionine product. The environmentally-friendly method has the advantages that the highly-toxic and rotten dimethyl diselenide is prevented from being used, so that the damage to the environment and operators are greatly reduced; the yield is high, the production cost is lower, the product purity is high, and optical and pure selenomethionine can be produced by large batch; and the obtained product can be used for preparing the intermediate of a selenium-containing medicine, and solves the difficulty that the selenomethionine and the related medicines can not be popularized.

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 present invention relates to methods of treating fungal infections with a drug combination: a first compound that inhibits the activity or expression of the protein FKBP12 and a second compound that inhibits the activity or expression of homoserine dehydrogenase. Evidence indicates that dual inhibitors of proteins FKBP12 and homoserine dehydrogenase are lethal to fungi. Such an approach should be minimally toxic since this combination therapy targets a biosynthetic pathway that is conserved in fungi but not in mammals.

The present invention relates to a microorganism producing L-methionine precursor, O-succinylhomoserine, 1) the homoserine O-succinyltransferase activity (EC2.3.1.46) is introduced and enhanced, wherein the homoserine O-succinyltransferase activity is feed back resistant to methionine; and 2) the aspartokinase or homoserine dehydrogenase activity (EC2.7.2.4 or 1.1.1.3) is enhanced, and a method of producing L-methionine precursor using the microorganism.

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.

The present invention relates to a process for the production of methionine or its derivatives by culturing a microorganism in an appropriate culture medium comprising a source of carbon and a source of sulfur. The microorganism claimed is modified in a way that the production of cysteine and / or C1 units is enhanced and / or the transfer potential of the C1 units on 10 homocysteine is increased or optimized. The isolation of methionine or its derivates from the fermentation medium is also claimed.