70 results about "Acyl-Homoserine Lactones" patented technology

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 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.

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 invention discloses a cell-based biosensor used for detection of bacterial-colony signal molecules and a preparation method of the cell-based biosensor. Graphene oxide is added to a sodium alginate solution to form a sodium alginate/graphene oxide mixture, a cell suspension solution is inoculated to the surface of a gold electrode, cells are covered and wrapped with the sodium alginate/graphene oxide mixture and are cultivated and inoculated after soaked in a CaCl2 insulation to form hydrogel to obtain the cell-based biosensor; the constructed cell-based biosensor is applied to detection of 3OC12-HSL of N-acyl-homoserine lactone (AHLs) standard substances in the bacterial-colony signal molecules, good linear relation of the concentration at 0.01mu M to 1um M is achieved, and detection limit is 0.01um M. Identification, conduction and detection on the standard substances of the colony signal molecules are realized accurately, efficiently and rapidly, shortcomings in traditional detection methods are overcome, and the cell-based biosensor is simple in manufacture, low in cost and good in application prospect.

The invention relates to a double-tagging microbial cell biosensor for detecting N-acyl homoserine lactone (AHL), and the biosensor is suitable for detection of AHL and characterization of host cells in the environment. The cell biosensor comprises: Escherichia coli used as host cells for carrying recombinant plasmids; recombinant plasmid containing an ahlI promoter responding to AHL, a cherry red fluorescent protein reporter gene mCherry and an AHL regulatory protein gene ahlR; and a neomycin phosphotransferase promoter gene nptII for characterization of host bacteria, a green fluorescent protein reporter gene gfp and a T1-4 pUC19 plasmid of four terminator rrnb tandem sequence. According to the biosensor, constitutive type of expression green fluorescent protein is used to characterize the host bacteria; the response time to AHL is 6 h; and the minimum detectable concentration of AHL is 50 nmol / L. The biosensor has the advantages of high sensitivity, fast response, low cost and simple operation, and can be widely applied to detection of AHL and host characterization in the environment.

Use of bacterial cells of the genus Tenacibaculum, from the crude cellular extract or from its cultivation supernatants, capable of degrading N-acyl homoserine lactones, for quorum quenching, for treatment of infectious bacterial illnesses or to inhibit formation of biofilms.

The invention discloses a method for effectively enhancing the sulfur oxidation performance of acidithiobacillus ferrooxidans. The method comprises the following steps: (1) constructing a recombinantbacterium A. ferrooxidans (pJRD215-taq-afeI), increasing the copy number of acyl homoserine lactone synthetase gene (afeI), by expressing afeI gene, increasing the content of acyl homoserine lactone (AHL) so as to enhance the sulfur oxidation performance of A. ferrooxidans; or (2) during the culture process of wild type A. ferrooxidans, adding exogenous acyl homoserine lactone (AHL) with a concentration of 5.4-10*10<3> mg/mL to enhance the sulfur oxidation performance of A. ferrooxidans through the increased content of AHL. The provided method has a wide application prospect in increasing theefficiency of industrial mineral leaching in the biological metallurgy field.

The invention discloses a quorum-quenching enzyme OLB-26, and a coding gene and application thereof. The protein OLB-26 is a fusion protein disclosed as (a) or (b): (a) protein composed of amino acid sequence disclosed as Sequence 1 in the sequence table; or (b) protein derived from Sequence 1 in the sequence table with quorum-quenching enzyme functions, which is subjected to substitution and/or deletion and/or addition of one or more amino acid residues of the amino acid sequence disclosed as Sequence 1 in the sequence table. The experiment proves that the fusion protein OLB-26 disclosed by the invention has substrate specificity, can degrade long-chain and short-chain N-acylhomoserine lactones, has the specific activity of 7.59 U/mg as a quenching enzyme, is very stable within the pH range of 6.0-8.0, and can maintain more than 80% of enzyme activity; and the quorum-quenching enzyme OLB-26 has favorable heat stability, and the relative enzyme activity at 50 DEG C for 20 minutes is still 100%. The fusion protein OLB-26 disclosed by the invention can be used for preparing a novel biocontrol enzyme preparation.

A novel small molecule antagonizes two types of acyl homoserine lactone receptors: membrane-bound and cytoplasmic. A focused library of analogs and derivatives of the original antagonist was synthesized. Analog and derivative molecules harbor a range of activities. The novel small molecule and most potent antagonist protects the eukaryote Caenorhabditis elegans from quorum-sensing-mediated killing by the bacterial pathogen Chromobacterium violaceum. The saving of C. elegans demonstrates the use of these molecules as small molecule antimicrobials.

The invention belongs to the field of medicinal chemistry and discloses benzene ring substituted N-acyl homoserine lactone compounds with bacterial quorum-sensing inhibition activity as well as a synthetic method and an application of the compounds. The preparation method is simple, mild in condition and high in yield. In-vitro activity test results prove that the benzene ring substituted N-acyl homoserine lactone compounds have an obvious inhibition effect on an LAS system and a PQS system of pseudomonas aeruginosa and can be used for preparing bacterial quorum-sensing resisting drugs, antibacterial synergists, antibacterial drugs or antitumor drugs. The general formula of the chemical structure of the compounds is shown in the specification.

The invention provides an MBR (Membrane Bioreactor) membrane pollution control method based on microbial quorum sensing quenching. The method comprises the following steps: (1) immobilizing quorum sensing quenching bacterium thalli by using an immobilized high polymer material to obtain immobilized quorum sensing quenching bacteria; and (2) putting the immobilized quorum sensing quenching bacteriainto a pretreatment tank in front of an MBR reaction tank, and intercepting the immobilized quorum sensing quenching bacteria in the pretreatment tank, wherein the quorum sensing quenching bacteria can degrade acyl homoserine lactone. According to the invention, the input of signal molecules entering the MBR reaction tank can be effectively reduced, the control effect on MBR membrane pollution isobvious, and the period of MBR membrane pollution is increased by 100-200%. The defect that the number of immobilized quorum sensing quenching bacteria needs to be strictly controlled in in-situ QQ is overcome, and the performance of the quorum sensing quenching bacteria and control over membrane pollution can be fully exerted. The method is simple in operation process and convenient for application of a sewage treatment plant.

The invention discloses N-acylhomoserine lactonase QsdA-RH5 with substrate specificity and a coding gene and application thereof. The protein QsdA-RH5 is (a) protein consisting of the amino acid sequences shown by sequence 1 in a sequence table, or (b) protein obtained by substituting and/or losing and/or adding one or multiple amino acid residues of the amino acid sequence of the sequence 1 in the sequence table, having the function of N-acylhomoserine lactonase and derived from the sequence 1 in the sequence table. Experiments prove that the QsdA-RH5 protein provided by the invention has substrate specificity and can degrade various N-acylhomoserine lactone without substituent groups; the specific activity of the QsdA-RH5 protein serving as N-acylhomoserine lactonase is 292.83U/mg and is stable in a pH range of 4.0-12.0, and more than 90% of enzyme activity can be maintained; and moreover, the thermal stability is better, and relative enzyme activity after keeping temperature at 70 DEG C for 10 minutes is still 100%. The QsdA-RH5 protein provided by the invention can be used for preparing a novel bio-control enzyme preparation.

The invention relates to a screening method of indigenous group induction quenched bacteria and a purpose, and belongs to the technical field of strain screening, wherein the group induction quenchedbacteria are screened by the following steps of screening out strains using N-acyl-homoserine lactone as a unique carbon source to grow from active sludge sampled from an indigenous MBR device; verifying the N-acyl-homoserine lactone degradation capability of the screened group induction quenched bacteria; embedding the group induction quenched bacteria by a PVDF flat plate film to prepare a bacterium bag; verifying the N-acyl-homoserine lactone degradation capability of the prepared group induction quenched bacterium bag. The product has a good degradation effect on the N-acyl-homoserine lactone. The product has the advantages that the used raw materials are safe and non-toxicity; the environmental-friendly effects are achieved; the manufacturing is simple, fast and convenient; the separation and recovery from the active sludge mixed solution are easy, and the like. The screening method can be used for the film pollution control in the MBR waste water treatment process and the like.

The invention discloses a device and a method for improving integrated partial denitrification-anaerobic ammonia oxidation coupling denitrification performance, and belongs to the field of sewage treatment. Partial denitrification granular sludge is arranged at the bottommost part of the reactor, anaerobic ammonia oxidation granular sludge is arranged at the middle part of the reactor, and the anaerobic ammonia oxidation granular sludge in the reactor is uniformly mixed with acinetobacter JQ1004 embedded particles. The method comprises the following steps: carrying out enhanced starvation culture on acinetobacter JQ1004, so that the acinetobacter JQ1004 grows in a stable period and can secrete more acyl homoserine lactone (AHLs) signal molecules, and then putting cultured acinetobacter JQ1004 embedded particles in the stable period and anaerobic ammonia oxidation particle sludge into the same reaction device. The acinetobacter JQ1004 can consume an organic carbon source to reduce nitrate nitrogen under an anoxic condition, the influence of organic matters on anaerobic ammonia oxidation is reduced, and meanwhile, acyl homoserine lactone signal molecules generated by the acinetobacter JQ1004 can also improve the activity of anaerobic ammonia oxidizing bacteria.

The invention relates to N-acyl homoserine lactonase and a medicine thereof. An amino acid sequence of the N-acyl homoserine lactonase and a sequence as shown in SEQ ID NO.1 are at least 90% homologous, and the amino acid sequence of the N-acyl homoserine lactonase has N-acyl homoserine lactonase activity. The invention further provides a nucleotide sequence encoding the lactonase, an expression vector and a heterogenous expression strain. The medicine can treat (pseudomonas aeruginosa) infection. The N-acyl homoserine lactonase catalyzes lactone bonds of N-acyl homoserine lactone to hydrolyze, so that signal molecules between pseudomonas aeruginosa are quenched, and quorum sensing is interfered and inhibited. Compared with other N-acyl homoserine lactonase, the N-acyl homoserine lactonase has wider substrate adaptability and more efficient degradation activity and better effects when serving as the medicine for treating pseudomonas aeruginosa infection.