salicylates and phthalic-acid

Naphthalene, as a component of crude oil, is a common environmental pollutant. Biochemical and genetic aspects of naphthalene catabolism have been examined in most detail in the bacteria of Pseudomonas genus. In pseudomonads, the key intermediate in naphthalene degradation is salicylate. In this study, we investigated the ability of Rhodococcus opacus strain 3D to utilize naphthalene as a sole carbon and energy source. The characteristic feature of this strain is the inability to grow in the mineral medium supplemented with salicylate (typical intermediate of naphthalene degradation in Gram-negative bacteria). The absence of salicylate hydroxylase activity and salicylate accumulation in the course of R. opacus 3D cultivation in the mineral medium supplemented with naphthalene indicated existence of an alternative pathway of naphthalene oxidation. At the same time, R. opacus 3D was able to use monoaromatic compounds (salts of gentisic, ortho-phthalic, and 2-hydroxycinnamic acids and coumarin) as growth substrates. Based on the analysis of enzymatic activities, identification of the reaction intermediates, genetic determinants, and growth substrates, we concluded that R. opacus 3D carries out naphthalene degradation through an alternative pathway via formation of ortho-phthalic acid, which is untypical for pseudomonads. Using mass spectrometry, we showed for the first time that salicylic acid associate formed in trace amounts in the process of naphthalene degradation is not further metabolized and accumulated in the growth medium in a form of a dimer.

Topics: Carbon; Cinnamates; Dimerization; Mass Spectrometry; Metabolic Networks and Pathways; Mixed Function Oxygenases; Naphthalenes; Phthalic Acids; Pseudomonas; Rhodococcus; Salicylates; Sewage; Wastewater; Water Pollutants, Chemical; Water Pollution; Water Purification

Mechanisms by which dissolved organic matter (DOM) mediates the photochemical reduction of Hg(II) in aquatic ecosystems are not fully understood, owing to the heterogeneous nature and complex structural properties of DOM. In this work, naturally occurring aromatic compounds including salicylic, 4-hydrobenzoic, anthranilic, 4-aminobenzoic, and phthalic acid were systematically studied as surrogates for DOM in order to gain an improved mechanistic understanding of these compounds in the photoreduction of Hg(II) in water. We show that the photoreduction rates of Hg(II) are influenced not only by the substituent functional groups such as -OH, -NH(2) and -COOH on the benzene ring, but also the positioning of these functional groups on the ring structure. The Hg(II) photoreduction rate decreases in the order anthranilic acid>salicylic acid>phthalic acid according to the presence of the -NH(2), -OH, -COOH functional groups on benzoic acid. The substitution position of the functional groups affects reduction rates in the order anthranilic acid>4-aminobenzoic acid and salicylic acid>4-hydroxybenzoic acid. Reduction rates correlate strongly with ultraviolet (UV) absorption of these compounds and their concentrations, suggesting that the formation of organic free radicals during photolysis of these compounds is responsible for Hg(II) photoreduction. These results provide insight into the role of low-molecular-weight organic compounds and possibly DOM in Hg photoredox transformation and may thus have important implications for understanding Hg geochemical cycling in the environment.

Topics: 4-Aminobenzoic Acid; Mercury Compounds; Molecular Weight; ortho-Aminobenzoates; Oxidation-Reduction; Parabens; Photolysis; Phthalic Acids; Salicylates; Water; Water Pollutants, Chemical

A Moraxella sp. strain VG45 capable of utilizing o-phthalate and salicylate as a sole source of carbon and energy was isolated. The degradation of o-phthalate occurs via phthalate 4,5-dioxygenase, 4,5-dihydro-4,5-dihydroxyphthalate dehydrogenase, 4,5-dihydroxyphthalate decarboxylase and protocatechuate 4,5-dioxygenase. Salicylate is degraded via salicylate 5-hydroxylase, gentisate 1,2-dioxygenase and then by a glutathione-independent maleylpyruvate hydrolase. Further, a plasmid of app. 60 kilobase pairs (kb) is involved in the degradation of the o-phthalate and salicylate and the enzymes of these two pathways are independently regulated in strain VG45.

Topics: Biodegradation, Environmental; Dioxygenases; Hydroxybenzoates; Mixed Function Oxygenases; Moraxella; Oxidoreductases; Oxygenases; Phthalic Acids; Plasmids; Salicylates; Salicylic Acid

(1) In order to explore the possible mechanism that organic reagents used in the incubation step of the plasma renin activity (PRA) analysis act as a angiotensinase inhibitors we did angiotensin I (AI) recovery studies from plasma with such reagents. The organic acids and their mean difference in percent recovery of AI as compared to that for hydrochloric acid (HCI) are respectively as follows for one and a three hour incubation time: maleic (0.7%, 4.5%); and potassium hydrogen phthalate (KHphthalate) (7.2%, 9.6%). The tris(hydroxymethyl)aminomethane (Tris) organic acid salts and their mean difference in percent recovery of AI as compared to that for Tris-HCl are as follows for a one hour incubation: Tris-acetylsalicylate (3.6%), Tris-phenoxyacetate (3.6%), Tris-benzoate (2.6%), and Tris-salicylate (4.9%). (2) Of the reagents studied KHphthalate after a three hour incubation produced a statistically significant difference from the HCl reagent. The recovery data for all the organic reagents suggested that the primary mechanism of action was not that of an angiotensinase inhibitory one.

Topics: Angiotensin I; Angiotensins; Aspirin; Benzoates; Buffers; Humans; Hydrochloric Acid; Maleates; Phenoxyacetates; Phthalic Acids; Protease Inhibitors; Salicylates; Tromethamine

Topics: Acids; Benzoates; Chemistry, Pharmaceutical; Halogens; Naphthalenes; Phenacetin; Phthalic Acids; Prednisolone; Research; Salicylates; Salts; Theophylline