Salicylic Acid: A compound obtained from the bark of the white willow and wintergreen leaves. It has bacteriostatic, fungicidal, and keratolytic actions.Salicylates: The salts or esters of salicylic acids, or salicylate esters of an organic acid. Some of these have analgesic, antipyretic, and anti-inflammatory activities by inhibiting prostaglandin synthesis.Oxylipins: Eighteen-carbon cyclopentyl polyunsaturated fatty acids derived from ALPHA-LINOLENIC ACID via an oxidative pathway analogous to the EICOSANOIDS in animals. Biosynthesis is inhibited by SALICYLATES. A key member, jasmonic acid of PLANTS, plays a similar role to ARACHIDONIC ACID in animals.Cyclopentanes: A group of alicyclic hydrocarbons with the general formula R-C5H9.Plant Diseases: Diseases of plants.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.Arabidopsis: A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.Plant Growth Regulators: Any of the hormones produced naturally in plants and active in controlling growth and other functions. There are three primary classes: auxins, cytokinins, and gibberellins.Pseudomonas syringae: A species of gram-negative, fluorescent, phytopathogenic bacteria in the genus PSEUDOMONAS. It is differentiated into approximately 50 pathovars with different plant pathogenicities and host specificities.Ethylenes: Derivatives of ethylene, a simple organic gas of biological origin with many industrial and biological use.Arabidopsis Proteins: Proteins that originate from plants species belonging to the genus ARABIDOPSIS. The most intensely studied species of Arabidopsis, Arabidopsis thaliana, is commonly used in laboratory experiments.Plant Immunity: The inherent or induced capacity of plants to withstand or ward off biological attack by pathogens.Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)Plants, Genetically Modified: PLANTS, or their progeny, whose GENOME has been altered by GENETIC ENGINEERING.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Tobacco: A plant genus of the family SOLANACEAE. Members contain NICOTINE and other biologically active chemicals; its dried leaves are used for SMOKING.Disease Resistance: The capacity of an organism to defend itself against pathological processes or the agents of those processes. This most often involves innate immunity whereby the organism responds to pathogens in a generic way. The term disease resistance is used most frequently when referring to plants.Oomycetes: Eukaryotes in the group STRAMENOPILES, formerly considered FUNGI, whose exact taxonomic level is unsettled. Many consider Oomycetes (Oomycota) a phylum in the kingdom Stramenopila, or alternatively, as Pseudofungi in the phylum Heterokonta of the kingdom Chromista. They are morphologically similar to fungi but have no close phylogenetic relationship to them. Oomycetes are found in both fresh and salt water as well as in terrestrial environments. (Alexopoulos et al., Introductory Mycology, 4th ed, pp683-4). They produce flagellated, actively motile spores (zoospores) that are pathogenic to many crop plants and FISHES.Isonicotinic Acids: Heterocyclic acids that are derivatives of 4-pyridinecarboxylic acid (isonicotinic acid).Botrytis: A mitosporic Leotiales fungal genus of plant pathogens. It has teleomorphs in the genus Botryotina.ThiadiazolesWarts: Benign epidermal proliferations or tumors; some are viral in origin.Genes, Plant: The functional hereditary units of PLANTS.Gentisates: Salts and esters of gentisic acid.Tobacco Mosaic Virus: The type species of TOBAMOVIRUS which causes mosaic disease of tobacco. Transmission occurs by mechanical inoculation.Alternaria: A mitosporic Loculoascomycetes fungal genus including several plant pathogens and at least one species which produces a highly phytotoxic antibiotic. Its teleomorph is Lewia.Plants, Toxic: Plants or plant parts which are harmful to man or other animals.Phenylalanine Ammonia-Lyase: An enzyme that catalyzes the deamination of PHENYLALANINE to form trans-cinnamate and ammonia.Scopoletin: Plant growth factor derived from the root of Scopolia carniolica or Scopolia japonica.Keratolytic Agents: Agents that soften, separate, and cause desquamation of the cornified epithelium or horny layer of skin. They are used to expose mycelia of infecting fungi or to treat corns, warts, and certain other skin diseases.Intramolecular Transferases: Enzymes of the isomerase class that catalyze the transfer of acyl-, phospho-, amino- or other groups from one position within a molecule to another. EC 5.4.Immunity, Innate: The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from the presence of naturally occurring ANTI-INFECTIVE AGENTS, constitutional factors such as BODY TEMPERATURE and immediate acting immune cells such as NATURAL KILLER CELLS.Aspirin: The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. (From Martindale, The Extra Pharmacopoeia, 30th ed, p5)Cryotherapy: A form of therapy consisting in the local or general use of cold. The selective destruction of tissue by extreme cold or freezing is CRYOSURGERY. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Peronospora: A genus of OOMYCETES in the family Peronosporaceae. Most species are obligatory parasites and many are plant pathogens.Plant Roots: The usually underground portions of a plant that serve as support, store food, and through which water and mineral nutrients enter the plant. (From American Heritage Dictionary, 1982; Concise Dictionary of Biology, 1990)Anacardic Acids: A group of 6-alkyl SALICYLIC ACIDS that are found in ANACARDIUM and known for causing CONTACT DERMATITIS.Lycopersicon esculentum: A plant species of the family SOLANACEAE, native of South America, widely cultivated for their edible, fleshy, usually red fruit.Hydroxybenzoates: Benzoate derivatives substituted by one or more hydroxy groups in any position on the benzene ring.Aminosalicylic Acids: A group of 2-hydroxybenzoic acids that can be substituted by amino groups at any of the 3-, 4-, 5-, or 6-positions.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Pseudomonas: A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in nature. Some species are pathogenic for humans, animals, and plants.Abscisic Acid: Abscission-accelerating plant growth substance isolated from young cotton fruit, leaves of sycamore, birch, and other plants, and from potatoes, lemons, avocados, and other fruits.RNA, Plant: Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis.Ascomycota: A phylum of fungi which have cross-walls or septa in the mycelium. The perfect state is characterized by the formation of a saclike cell (ascus) containing ascospores. Most pathogenic fungi with a known perfect state belong to this phylum.Indenes: A family of fused-ring hydrocarbons isolated from coal tar that act as intermediates in various chemical reactions and are used in the production of coumarone-indene resins.Glycolates: Derivatives of ACETIC ACID which contain an hydroxy group attached to the methyl carbon.Capsicum: A plant genus of the family SOLANACEAE. The hot peppers yield CAPSAICIN, which activates VANILLOID RECEPTORS. Several varieties have sweet or pungent edible fruits that are used as vegetables when fresh and spices when the pods are dried.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Exopeptidases: A sub-class of PEPTIDE HYDROLASES that act only near the ends of polypeptide chains.Hydrogen Peroxide: A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.Benzoic Acid: A fungistatic compound that is widely used as a food preservative. It is conjugated to GLYCINE in the liver and excreted as hippuric acid.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Acetates: Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.Hydroponics: A technique for growing plants in culture solutions rather than in soil. The roots are immersed in an aerated solution containing the correct proportions of essential mineral salts. (From Concise Dictionary of Biology, 1990)Hippurates: Salts and esters of hippuric acid.Chemexfoliation: Application of a cauterant to the skin for the purpose of causing a superficial destruction of the epidermis and upper layers of the dermis. After healing, the treated area has new epithelium.Host-Pathogen Interactions: The interactions between a host and a pathogen, usually resulting in disease.Anti-Inflammatory Agents, Non-Steroidal: Anti-inflammatory agents that are non-steroidal in nature. In addition to anti-inflammatory actions, they have analgesic, antipyretic, and platelet-inhibitory actions.They act by blocking the synthesis of prostaglandins by inhibiting cyclooxygenase, which converts arachidonic acid to cyclic endoperoxides, precursors of prostaglandins. Inhibition of prostaglandin synthesis accounts for their analgesic, antipyretic, and platelet-inhibitory actions; other mechanisms may contribute to their anti-inflammatory effects.Phytophthora: A genus of destructive parasitic OOMYCETES in the family Peronosporaceae, order Peronosporales, affecting numerous fruit, vegetable, and other crops. Differentiation of zoospores usually takes place in the sporangium and no vesicle is formed. It was previously considered a fungus.Naphthaleneacetic Acids: Naphthalene derivatives containing the -CH2CCO2H radical at the 1-position, the 2-position, or both. Compounds are used as plant growth regulators to delay sprouting, exert weed control, thin fruit, etc.Mesalamine: An anti-inflammatory agent, structurally related to the SALICYLATES, which is active in INFLAMMATORY BOWEL DISEASE. It is considered to be the active moiety of SULPHASALAZINE. (From Martindale, The Extra Pharmacopoeia, 30th ed)Carboxylic Ester Hydrolases: Enzymes which catalyze the hydrolysis of carboxylic acid esters with the formation of an alcohol and a carboxylic acid anion.Magnaporthe: A genus of FUNGI, in the family Magnaporthaceae of uncertain position (incertae sedis). It is best known for its species, M. grisea, which is one of the most popular experimental organisms of all fungal plant pathogens. Its anamorph is PYRICULARIA GRISEA.Bromisovalum: A sedative and mild hypnotic with potentially toxic effects.Ascorbate Peroxidases: Peroxidases that utilize ASCORBIC ACID as an electron donor to reduce HYDROGEN PEROXIDE to WATER. The reaction results in the production of monodehydroascorbic acid and DEHYDROASCORBIC ACID.Oryza sativa: Annual cereal grass of the family POACEAE and its edible starchy grain, rice, which is the staple food of roughly one-half of the world's population.ChitinasePlant Exudates: Substances released by PLANTS such as PLANT GUMS and PLANT RESINS.CinnamatesMixed Function Oxygenases: Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.Verticillium: A mitosporic fungal genus commonly isolated from soil. Some species are the cause of wilt diseases in many different plants.Cicer: A plant genus of the family FABACEAE known for the edible beans.Seedling: Very young plant after GERMINATION of SEEDS.Defensins: Family of antimicrobial peptides that have been identified in humans, animals, and plants. They are thought to play a role in host defenses against infections, inflammation, wound repair, and acquired immunity.Benzoates: Derivatives of BENZOIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxybenzene structure.Amitrole: A non-selective post-emergence, translocated herbicide. According to the Seventh Annual Report on Carcinogens (PB95-109781, 1994) this substance may reasonably be anticipated to be a carcinogen. (From Merck Index, 12th ed) It is an irreversible inhibitor of CATALASE, and thus impairs activity of peroxisomes.Indoleacetic Acids: Acetic acid derivatives of the heterocyclic compound indole. (Merck Index, 11th ed)Colletotrichum: A genus of mitosporic Phyllachoraceae fungi which contains at least 40 species of plant parasites. They have teleomorphs in the genus Glomerella (see PHYLLACHORALES).Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Phenols: Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.Tablets, Enteric-Coated: Tablets coated with material that delays release of the medication until after they leave the stomach. (Dorland, 28th ed)DNA, Plant: Deoxyribonucleic acid that makes up the genetic material of plants.Herbivory: The act of feeding on plants by animals.Thiazoles

Distribution kinetics of salicylic acid in the dual-perfused rat liver preparation. (1/1096)

The hepatic distribution kinetics of salicylic acid was determined using a single-pass dual hepatic artery (HA) and portal vein (PV) perfused in situ rat liver preparation. Bolus doses of [14C]salicylic acid and of reference markers ([3H]-water and [14C]-sucrose) were injected in a random order into either the HA or PV and then, after an appropriate interval, into the alternate vessel. The hepatic outflow profile of [14C]salicylic acid displayed a characteristic sharp peak followed by a slower eluting tail, whereas sucrose and water displayed unimodal outflow profiles. The biphasic outflow profile indicates that the hepatic distribution of salicylic acid is not instantaneous but is limited by a permeability barrier. The in situ permeability surface area product for [14C]salicylic acid was 3.35 +/- 0.26 ml/min/g for PV and 7.45 +/- 1. 50 ml/min/g for HA administration. Furthermore, theory dictates that hepatic uptake is influenced by both perfusion and permeability if effective permeability surface area product/blood flow ratio lies between the values of 0.06 and 7.0. Our estimates (3.0 for venous output and 6.7 for arterial input) indicate that hepatic uptake of salicylic acid is dependent on both perfusion and permeability. The volume terms were calculated using two different methods, standard and specific. Regardless of the compound and method, the volume of distribution after arterial administration was larger than that after venous administration. In addition, a volume of distribution approximately twice that of the total aqueous space (i.e., HA, 2.23 +/- 0.13 versus 1.10 +/- 0.07 ml/g; PV, 1.72 +/- 0.16 versus 0.68 +/- 0.04 ml/g) implies that salicylic acid has a significant affinity for hepatic tissue. A similar tissue-to-perfusate partition coefficient associated with HA and PV input (5.40 +/- 0.38 versus 6. 48 +/- 0.56) indicates that affinity of salicylic acid for hepatic tissue is independent of the route of input.  (+info)

Salicylate inhibits LDL oxidation initiated by superoxide/nitric oxide radicals. (2/1096)

Simultaneously produced superoxide/nitric oxide radicals (O2*-/NO*) could form peroxynitrite (OONO-) which has been found to cause atherogenic, i.e. oxidative modification of LDL. Aromatic hydroxylation and nitration of the aspirin metabolite salicylate by OONO- has been reported. Therefore we tested if salicylate may be able to protect LDL from oxidation by O2*-/NO* by scavenging the OONO reactive decomposition products. When LDL was exposed to simultaneously produced O2*-/NO* using the sydnonimine SIN-1, salicylate exerted an inhibitory effect on LDL oxidation as measured by TBARS and lipid hydroperoxide formation and alteration in electrophoretic mobility of LDL. The cytotoxic effect of SIN-1 pre-oxidised LDL to endothelial cells was also diminished when salicylate was present during SIN-1 treatment of LDL. Spectrophotometric analysis revealed that salicylate was converted to dihydroxybenzoic acid (DHBA) derivatives in the presence of SIN-1. 2,3- and 2,5-DHBA were even more effective to protect LDL from oxidation by O2*-/NO*. Because O2*-/NO* can occur in vivo, the results may indicate that salicylate could act as an efficacious inhibitor of O2*-/NO* initiated atherogenic LDL modification, thus further supporting the rationale of aspirin medication regarding cardiovascular diseases.  (+info)

Is arcA3 a possible mediator in the signal transduction pathway during agonist cell cycle arrest by salicylic acid and UV irradiation? (3/1096)

Progression of BY-2 tobacco cells through the cell cycle was followed after treatments with ultra violet (UV) and salicylic acid (SA) used as a potent inhibitor of the octadecanoid pathway which can mediate response to UV irradiation. Cells in S phase were more sensitive than G0/G1 or G2 cells to UV irradiation. Although SA efficiently blocked cells in G0/G1 or G2, it did not block S phase synchronized cells. UV and SA applied simultaneously to cells in G0/G1 delayed the cell cycle progression more than each one separately. Therefore UV irradiation and SA act as agonists to arrest BY-2 cells at cell cycle entry. To further investigate the signalling pathway mediating UV response, we complemented a UV-sensitive Escherichia coli strain with a Nicotiana xanthi cDNA expression library. A cDNA (arcA3) whose coding sequence is identical to the 2,4-D induced arcA cDNA cloned by Ishida et al. (1993) was isolated. We show that arcA3 transcription is induced at cell cycle entry but not directly by the 2,4-D treatment. Moreover, arcA3 transcription is induced prior to the restriction point as shown with the CDK inhibitor roscovitine. The arcA3 transcription level is increased by UV irradiation but prevented by SA. Indeed, addition of SA prior to UV irradiation blocks the induction of arcA3 transcription. This suggests that arcA3 gene is modulated in both UV and SA responses, the SA effect preceding the UV step. Since arcA3 is 67% similar to RACK1 (functional homology), a rat intracellular receptor for protein kinase C, and possesses identical PKC fixation motifs, it is hypothesised that the arcA3 gene is involved in UV and SA cell cycle arrest.  (+info)

Inverse relationship between systemic resistance of plants to microorganisms and to insect herbivory. (4/1096)

Pre-inoculation of plants with a pathogen that induces necrosis leads to the development of systemic acquired resistance (SAR) to subsequent pathogen attack [1]. The phenylpropanoid-derived compound salicylic acid (SA) is necessary for the full expression of both local resistance and SAR [2] [3]. A separate signaling pathway involving jasmonic acid (JA) is involved in systemic responses to wounding and insect herbivory [4] [5]. There is evidence both supporting and opposing the idea of cross-protection against microbial pathogens and insect herbivores [6] [7]. This is a controversial area because pharmacological experiments point to negative cross-talk between responses to systemic pathogens and responses to wounding [8] [9] [10], although this has not been demonstrated functionally in vivo. Here, we report that reducing phenylpropanoid biosynthesis by silencing the expression of phenylalanine ammonialyase (PAL) reduces SAR to tobacco mosaic virus (TMV), whereas overexpression of PAL enhances SAR. Tobacco plants with reduced SAR exhibited more effective grazing-induced systemic resistance to larvae of Heliothis virescens, but larval resistance was reduced in plants with elevated phenylpropanoid levels. Furthermore, genetic modification of components involved in phenylpropanoid synthesis revealed an inverse relationship between SA and JA levels. These results demonstrate phenylpropanoid-mediated cross-talk in vivo between microbially induced and herbivore-induced pathways of systemic resistance.  (+info)

Nanogram amounts of salicylic acid produced by the rhizobacterium Pseudomonas aeruginosa 7NSK2 activate the systemic acquired resistance pathway in bean. (5/1096)

Root colonization by specific nonpathogenic bacteria can induce a systemic resistance in plants to pathogen infections. In bean, this kind of systemic resistance can be induced by the rhizobacterium Pseudomonas aeruginosa 7NSK2 and depends on the production of salicylic acid by this strain. In a model with plants grown in perlite we demonstrated that Pseudomonas aeruginosa 7NSK2-induced resistance is equivalent to the inclusion of 1 nM salicylic acid in the nutrient solution and used the latter treatment to analyze the molecular basis of this phenomenon. Hydroponic feeding of 1 nM salicylic acid solutions induced phenylalanine ammonia-lyase activity in roots and increased free salicylic acid levels in leaves. Because pathogen-induced systemic acquired resistance involves similar changes it was concluded that 7NSK2-induced resistance is mediated by the systemic acquired resistance pathway. This conclusion was validated by analysis of phenylalanine ammonia-lyase activity in roots and of salicylic acid levels in leaves of soil-grown plants treated with Pseudomonas aeruginosa. The induction of systemic acquired resistance by nanogram amounts of salicylic acid is discussed with respect to long-distance signaling in systemic acquired resistance.  (+info)

Interaction of NPR1 with basic leucine zipper protein transcription factors that bind sequences required for salicylic acid induction of the PR-1 gene. (6/1096)

The Arabidopsis thaliana NPR1 has been shown to be a key regulator of gene expression during the onset of a plant disease-resistance response known as systemic acquired resistance. The npr1 mutant plants fail to respond to systemic acquired resistance-inducing signals such as salicylic acid (SA), or express SA-induced pathogenesis-related (PR) genes. Using NPR1 as bait in a yeast two-hybrid screen, we identified a subclass of transcription factors in the basic leucine zipper protein family (AHBP-1b and TGA6) and showed that they interact specifically in yeast and in vitro with NPR1. Point mutations that abolish the NPR1 function in A. thaliana also impair the interactions between NPR1 and the transcription factors in the yeast two-hybrid assay. Furthermore, a gel mobility shift assay showed that the purified transcription factor protein, AHBP-1b, binds specifically to an SA-responsive promoter element of the A. thaliana PR-1 gene. These data suggest that NPR1 may regulate PR-1 gene expression by interacting with a subclass of basic leucine zipper protein transcription factors.  (+info)

Environmental factors modulating antibiotic and siderophore biosynthesis by Pseudomonas fluorescens biocontrol strains. (7/1096)

Understanding the environmental factors that regulate the biosynthesis of antimicrobial compounds by disease-suppressive strains of Pseudomonas fluorescens is an essential step toward improving the level and reliability of their biocontrol activity. We used liquid culture assays to identify several minerals and carbon sources which had a differential influence on the production of the antibiotics 2,4-diacetylphloroglucinol (PHL), pyoluteorin (PLT), and pyrrolnitrin and the siderophores salicylic acid and pyochelin by the model strain CHA0, which was isolated from a natural disease-suppressive soil in Switzerland. Production of PHL was stimulated by Zn2+, NH4Mo2+, and glucose; the precursor compound mono-acetylphloroglucinol was stimulated by the same factors as PHL. Production of PLT was stimulated by Zn2+, Co2+, and glycerol but was repressed by glucose. Pyrrolnitrin production was increased by fructose, mannitol, and a mixture of Zn2+ and NH4Mo2+. Pyochelin production was increased by Co2+, fructose, mannitol, and glucose. Interestingly, production of its precursor salicylic acid was increased by different factors, i.e., NH4Mo2+, glycerol, and glucose. The mixture of Zn2+ and NH4Mo2+ with fructose, mannitol, or glycerol further enhanced the production of PHL and PLT compared with either the minerals or the carbon sources used alone, but it did not improve siderophore production. Extending fermentation time from 2 to 5 days increased the accumulation of PLT, pyrrolnitrin, and pyochelin but not of PHL. When findings with CHA0 were extended to an ecologically and genetically diverse collection of 41 P. fluorescens biocontrol strains, the effect of certain factors was strain dependent, while others had a general effect. Stimulation of PHL by Zn2+ and glucose was strain dependent, whereas PLT production by all strains that can produce this compound was stimulated by Zn2+ and transiently repressed by glucose. Inorganic phosphate reduced PHL production by CHA0 and seven other strains tested but to various degrees. Production of PLT but not pyrrolnitrin by CHA0 was also reduced by 100 mM phosphate. The use of 1/10-strength nutrient broth-yeast extract, compared with standard nutrient broth-yeast extract, amended with glucose and/or glycerol resulted in dramatically increased accumulations of PHL (but not PLT), pyochelin, and salicylic acid, indicating that the ratio of carbon source to nutrient concentration played a key role in the metabolic flow. The results of this study (i) provide insight into the biosynthetic regulation of antimicrobial compounds, (ii) limit the number of factors for intensive study in situ, and (iii) indicate factors that can be manipulated to improve bacterial inoculants.  (+info)

A functional 4-hydroxysalicylate/hydroxyquinol degradative pathway gene cluster is linked to the initial dibenzo-p-dioxin pathway genes in Sphingomonas sp. strain RW1. (8/1096)

The bacterium Sphingomonas sp. strain RW1 is able to use dibenzo-p-dioxin, dibenzofuran, and several hydroxylated derivatives as sole sources of carbon and energy. We have determined and analyzed the nucleic acid sequence of a 9,997-bp HindIII fragment downstream of cistrons dxnA1A2, which encode the dioxygenase component of the initial dioxygenase system of the corresponding catabolic pathways. This fragment contains 10 colinear open reading frames (ORFs), apparently organized in one compact operon. The enzymatic activities of some proteins encoded by these genes were analyzed in the strain RW1 and, after hyperexpression, in Escherichia coli. The first three ORFs of the locus, designated dxnC, ORF2, and fdx3, specify a protein with a low homology to bacterial siderophore receptors, a polypeptide representing no significant homology to known proteins, and a putative ferredoxin, respectively. dxnD encodes a 69-kDa phenol monooxygenase-like protein with activity for the turnover of 4-hydroxysalicylate, and dxnE codes for a 37-kDa protein whose sequence and activity are similar to those of known maleylacetate reductases. The following gene, dxnF, encodes a 33-kDa intradiol dioxygenase which efficiently cleaves hydroxyquinol, yielding maleylacetate, the ketoform of 3-hydroxy-cis,cis-muconate. The heteromeric protein encoded by dxnGH is a 3-oxoadipate succinyl coenzyme A (succinyl-CoA) transferase, whereas dxnI specifies a protein exhibiting marked homology to acetyl-CoA acetyltransferases (thiolases). The last ORF of the sequenced fragment codes for a putative transposase. DxnD, DxnF, DxnE, DxnGH, and DxnI (the activities of most of them have also been detected in strain RW1) thus form a complete 4-hydroxysalicylate/hydroxyquinol degradative pathway. A route for the mineralization of the growth substrates 3-hydroxydibenzofuran and 2-hydroxydibenzo-p-dioxin in Sphingomonas sp. strain RW1 thus suggests itself.  (+info)

  • Salicylic acid (from Latin salix , willow tree ) is a lipophilic monohydroxybenzoic acid , a type of phenolic acid , and a beta hydroxy acid (BHA). (
  • Salicylic acid is a Beta Hydroxy Acid which works on a much deeper level, even going inside the of pores to fight the appearance of blemishes, for better visible skin clarity. (
  • Salicylic Acid which is a Beta Hydroxy Acid (BHA) on the other hand behaves more like a systemic on the skin. (
  • Since Salicylic Acid, otherwise known as a Beta Hydroxy acid, acts like a systemic, it continues to work deep inside the skin which is why it can cause damage to the cell renewal process. (
  • Beta Hydroxy Acid. (
  • However, there are divided camps on the use of Beta Hydroxy Acids due to their ability to penetrate deep into the pores, breaking through the oily barrier which helps to break apart sebum buildup and unclog the pore. (
  • The chemical exfoliation with salicylic acid eliminates those dead cells, cleans and tightens the pores, purifies the skin and refines the texture. (
  • Salicylic acid works as a keratolytic, comedolytic, and bacteriostatic agent, causing the cells of the epidermis to shed more readily, opening clogged pores and neutralizing bacteria within, preventing pores from clogging up again by constricting pore diameter, and allowing room for new cell growth.Because of its effect on skin cells, salicylic acid is used in several shampoos to treat dandruff. (
  • In this study the effect of sunflower seed pretreatment with salicylic acid (100 mg/L) and potassium nitrate (2%) on its enhancing tolerance under different concentrations of cadmium (0, 50 and 100 mg/kg) were evaluated. (
  • This conversion of an incompatible to a compatible interaction could be reverted by spraying with high concentrations of salicylic acid or the synthetic analogue INA (2,6-dichloro-isonicotinic acid), indicating that SA is a key control molecule in plant resistance. (
  • A daily use of a blend of fruit acids in lower concentrations can have similar benefits through a cumulative effect without the irritation. (
  • The aim of this study was to investigate plasma and urine concentrations of salicylic acid (SA) after oral administration of three different single dosages (12.5 mg/kg, 25 mg/kg and 50 mg/kg) of acetylsalicylic acid (ASA) to eight horses in a cross-over designed study. (
  • Subsequent examination revealed that, in RNAi transgenic plants, genes related to salicylic acid were up-regulated, whereas those related to jasmonic acid and ethylene were generally down-regulated. (
  • The present findings suggested that NtAAA1 broadly functions in cellular metabolism, and particularly that, responding to jasmonic acid and/or ethylene signals, it might interfere with salicylic acid signaling. (
  • People who have acne sometimes use Salicylic acid as a topical remedy for the bumps that form on their face, back or other skin areas. (
  • Infused with, yep you guessed it, salicylic acid, the lightweight serum removes the build-up of oil and helps to balance its production - irritation is often caused by over production of oil by the sebaceous gland, after all. (
  • De The Inkey List Salicylic Acid Exfoliating Scalp Treatment is een licht gewicht serum dat speciaal ontwikkeld is om jeuk, schilferigheid en overmatige olieophoping op je hoofdhuid tegen te gaan. (
  • Dit serum werkt om de ophoping te verwijderen en scrubt de hoofdhuid zachtjes. (
  • Our ONATI Skin Care products using the cumulative effect will fit the bill for taking gentle care of your skin, through the use of a wonderful blend of fruit acids (AHA's) in our cleansers, facial toner, and facial serum without creating that ongoing pinkish irritation. (
  • They both have carboxylic acid groups (COOH) which is promising, this indicates acidity. (
  • However, the reactivity of both molecules will come from the carboxylic acid group, which is free and open to change around with other molecules. (
  • See the structures below, can you spot the carboxylic acid group? (
  • The reason for this can vary and are most likely to do with the placement of the carboxylic acid group and/or size and weight of the molecule. (
  • A balm specifically designed to promote skin renewing and help it recuperate after esthetic procedures (face peels, etc.) or repeated climatic exposure (sun, cold).Pyrrolidone carboxylic acid, naturally present in. (
  • Although acetylsalicylic acid (ASA) is not frequently used as a therapeutic agent in horses, its metabolite SA is of special interest in equestrianism since it is a natural component of many plants used as horse feed. (
  • Acetylsalicylic acid (ASA) was synthesized to have the same effects as SA with an improved gastric and systemic tolerability profile [ 3 ]. (
  • Sodium salicylate inhibits cyclo-oxygenase-2 activity independently of transcription factor (nuclear factor kappaB) activation: role of arachidonic acid. (
  • Salicylic acid as a medication is used most commonly to help remove the outer layer of the skin . (
  • Salicylic acid is dermatologists' answer to these stubborn zits, as it contains soothing properties, thus no wonder it is included in many acne- treatment skin care products. (
  • Salicylic acid is a hydroxy acid and as such, it gently removes skin cells. (
  • This is why salicylic acid can be used to exfoliate dead cells from around the eyes and mouth to reveal younger looking skin. (
  • When it is applied to a corn on your big toe or elsewhere, salicylic acid gently removes the skin cells and gets rid of the corn. (
  • Products that contain salicylic acid may cause tingling and a mild redness of the skin. (
  • You'll find salicylic acid mainly in pads that you rub on your skin. (
  • Hence, they are both pretty gentle acids, which is why they are great for sensitive skin. (
  • The answer lies in the action the acids take to decongest your skin. (
  • This foaming cleansing gel builds on the synergy of glycolic, lactic and salicylic acids to reveal clean and fresh skin. (
  • By removing dead skin cells, salicylic acid creates the space for new skin cells to grow. (
  • A facial peel is a great way to introduce professional strength acids to the skin. (
  • Use of concentrated solutions of salicylic acid may cause hyperpigmentation on unpretreated skin for those with darker skin types, as well as with the lack of use of a broad spectrum sunblock. (
  • Salicylic acid is extracted from the bark of the willow tree. (
  • Natural sources of salicylic acid include willow bark extract (Salix nigra) and wintergreen oil (Gaultheria procumbens). (
  • The use of salicylic acid in many skincare and beauty products is pretty common because of its clinically proven effectiveness and reliability in improving your skin's complexion. (
  • This system maintains the defense response at appropriate levels, so that detrimental necrosis is avoided, and therefore NtAAA1 may be regarded as a molecular switch of the salicylic acid signaling pathway. (
  • Thanks to its particular affinity with oil, this lipophilic acid penetrates deep into the sebaceous glands, inducing a regulation of sebum production. (
Salicylic acid
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