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At least 19 recordsLinked to original sources
PubMed1977

Influence of aromatic compounds on the interaction of activated C4 with EAC1.

The influence of amino acids and their derivatives on the formation of SAC14 from SAC1 and C4 were investigated. Among the compounds tested, aromatic amino acids containing phenolic hydroxyl group or carbobenzoxyl group inhibited the formation of SAC14. When aromatic compounds other than amino acids were tested, the inhibitory capacities of these compounds were found to relate to the substituent group incorporated in the aromatic ring. Aromatic compounds with subsituent groups with negative Hammett's substituent constant showed stronger inhibition. Conversely, compounds with group with positive constant showed weaker inhibition. These results may suggest that the increased electron density in the aromatic ring is responsible for the inhibition. Regardless of inhibition of SAC14 formation, these inhibitors did not affect the enzymatic action of EAC1 or C1 on C4 but inhibited the binding of activated C4 to EAC1.

Agglutination Tests↗
PubMed2025

Surfing in the storm: how Paraburkholderia xenovorans thrives under stress during biodegradation of toxic aromatic compounds and other stressors.

The adaptive mechanisms of Burkholderiales during the catabolism of aromatic compounds and abiotic stress are crucial for their fitness and performance. The aims of this report are to review the bacterial adaptation mechanisms to aromatic compounds, oxidative stress, and environmental stressful conditions, focusing on the model aromatic-degrading Paraburkholderia xenovorans LB400, other Burkholderiales, and relevant degrading bacteria. These mechanisms include (i) the stress response during aromatic degradation, (ii) the oxidative stress response to aromatic compounds, (iii) the metabolic adaptation to oxidative stress, (iv) the osmoadaptation to saline stress, (v) the synthesis of siderophore during iron limitation, (vi) the proteostasis network, which plays a crucial role in cellular function maintenance, and (vii) the modification of cellular membranes, morphology, and bacterial lifestyle. Remarkably, we include, for the first time, novel genomic analyses on proteostasis networks, carbon metabolism modulation, and the synthesis of stress-related molecules in P. xenovorans. We analyzed these metabolic features in silico to gain insights into the adaptive strategies of P. xenovorans to challenging environmental conditions. Understanding how to enhance bacterial stress responses can lead to the selection of more robust strains capable of thriving in polluted environments, which is critical for improving biodegradation and bioremediation strategies.

Biodegradation, Environmental↗
PubMedDate not supplied

[Utilization of aromatic compounds by yeasts of the genus Debaryomyces].

The ability to utilize phenol, catechol, resorcinol, hydroquinone, p-hydroxybenzoic acid, m-hydroxybenzoic acid, 2,4-dihydroxydenzoic acid, protocatechuic and gentisic acids was studied among 61 strains of 23 yeast species belonging to the Debaryomyces genus. All species characterized by active fermentation did not utilize these aromatic compounds. If fermentation was absent or weak, some of the aromatic compounds were utilized. This fact suggests an ecological difference between the two above yeast groups, justifying the subdivision of the Debaryomyces genus by some authors into two genera Debaryomyces and Torulaspora. No correlation could be established between the utilization of certain aromatic compounds and the yeast species classified on the basis of their behaviour toward carbohydrates. Therefore, classification of yeasts belonging to the Debaryomyces genus is artificial. It would be expedient to isolate a small number of typical species unless a more accurate relationship is established between cultures of the Debaryomyces genus referred to as different species.

Ascomycota↗
PubMed1977

Biochemistry of the bacterial catabolism of aromatic compounds in anaerobic environments.

Methods of aerobic degradation of aromatic compounds in the biosphere are well understood, but it is only relatively recently that it has been shown how some bacteria can also degrade these substrates in the absence of molecular oxygen. This occurs by photometabolism (Athiorhodaceae), nitrate respiration (Pseudomonas and Moraxella sp.) and methanogenic fermentation (a consortium) in which the benzene nucleus is first reduced and then cleaved by hydrolysis to yield aliphatic acids for cell growth. These methods may be used by microbial communities to catabolise man-made pollutants.

Anaerobiosis↗
PubMed2026

Characterization of carbon metabolism in a highly adhesive bacterium Acinetobacter sp. Tol 5 capable of assimilating diverse hydrocarbons and aromatic compounds.

Sustainable bioproduction requires developing robust microbial chassis with broad metabolic versatility and suitability for industrial applications. Acinetobacter sp. Tol 5 is a highly adhesive bacterium capable of utilizing various hydrocarbons, making it a promising chassis candidate for immobilized whole-cell catalysis. In this study, we characterized the carbon metabolism of Tol 5 by reconstructing metabolic pathway maps from its genomic data and analyzing the transcriptomes of cells grown on ethanol, hexadecane, toluene, and phenol. Genomic analysis revealed that Tol 5 has limited capacity for sugar utilization but possesses a wide range of metabolic pathways for alkane and aromatic compounds, including five distinct aromatic degradation routes that expand the known metabolic diversity of the genus Acinetobacter. Transcriptome analysis identified the specific pathway genes induced in response to each carbon source. During growth on phenol, alkylbenzene degradation genes were upregulated alongside phenol monooxygenase genes, suggesting possible substrate-dependent cross-regulation between aromatic degradation pathways. Gene disruption experiments indicated that phenol monooxygenase is required for phenol assimilation, whereas toluene dioxygenase may contribute to earlier entry into exponential growth while potentially limiting final biomass accumulation. These findings provide a comprehensive view of the carbon metabolism of Tol 5 and a basis for assessing its potential in bioprocesses using non-sugar carbon sources.

Acinetobacter↗
PubMed1977

Hydroxylation of aromatic compounds by reduced nicotinamide-adenine dinucleotide and phenazine methosulphate requires hydrogen peroxide and hydroxyl radicals, but not superoxide.

1. A mixture of NADH and phenazine methosulphate hydroxylates aromatic compounds at acidic pH values. 2. Hydroxylation is inhibited by catalase and by scavengers of the hydroxyl radical (-OH) but not by superoxide dismutase. 3. It is concluded that neither O2 leads to nor HO2- is sufficiently reactive to hydroxylate aromatic rings.

Hydrogen Peroxide↗
PubMed1977

Genetic regulation of UDP-glucuronosyltransferase induction by polycyclic aromatic compounds in mice. Co-segregation with aryl hydrocarbon (benzo(alpha)pyrene) hydroxylase induction.

Induction of hepatic 4-methylumbelliferone UDP-glucuronosyltransferase (EC 2.4.1.17) by polycyclic aromatic compounds, such as 3-methylcholanthrene or beta-naphthoflavone, occurs in C57BL/6N, A/J, PL/J, C3HeB/FeJ, and BALB/cJ but not in DBA/2N, AU/SsJ, AKR/J, or RF/J inbred strains of mice. This pattern of five responsive and five nonresponsive mouse strains parallels that of the Ah locus, which controls the induction of aryl hydrocarbon (benzo[alpha]pyrene) hydroxylase (EC 1.14.14.2). Induction of the transferase is maximal in C57BL/6N mice with 200 mg of 3-methylcholanthrene/kg body weight; no induction occurs in nonresponsive DBA/2N mice even at a dose of 400 mg/kg. The rise of inducible transferase activity lags 1 or more days behind the rise of inducible hydroxylase activity and peaks 5 days after a single dose of 3-methylcholanthrene. In offspring from the appropriate backcrosses and intercross between C57BL/6N and DBA/2N parent strains, the genetic expression of 3-methylcholanthrene-inducible transferase activity is inherited as an additive (co-dominant) trait. This expression differs distinctly from that of the inducible hydroxylase activity, which is inherited almost exclusively as a single autosomal dominant trait in these same animals. The more potent inducer 2,3,7,8-tetrachlorodibenzo-p-dioxin induces the transferase more than 3-fold in C57BL/6N mice and less than 2-fold in DBA/2N mice, whereas the hydroxylase is induced equally (about 8-fold) in both strains. A dose of 3-methylcholanthrene given 3 days after 2,3,7,8-tetrachlorodibenzo-p-dioxin, at a time when hydroxylase induction in both strains is very high, does not enhance the rise in inducible transferase activity seen in C57BL/6N or DBA/2N mice which have received 2,3,7,8-tetrachlorodibenzo-p-dioxin alone. These data indicate that (a) the inducibility of two metabolically coordinated membrane-bound enzyme activities may be regulated by a single genetic locus, and (b) although the hydroxylase can be fully induced in the nonresponsive DBA/2N strain by 2,3,7,8-tetrachlorodibenzo-p-dioxin prior to 3-methylcholanthrene treatment, metabolites of the 3-methylcholanthrene treatment, metabolites of the 3-methylcholanthrene treatment, metabolites of the 3-methylcholanthrene, presumably present in the liver, are incapable of inducing further the transferase activity. The difference in sensitivity between 3-methylcholanthrene and the more potent inducer 2,3,7,8-tetrachlorodibenzo-p-dioxin for both the hydroxylase and the transferase activities suggests the possibility of a common receptor in regulating both enzyme induction processes.

Age Factors↗
PubMed1978

Hepatic mixed-function oxidase activity in rainbow trout exposed to several polycyclic aromatic compounds.

The effects of polycyclic aromatic hydrocarbons (PAHs) on microsomal liver enzymes were examined in rainbow trout. Various PAHs (naphthalene through benzo(a)pyrene [B(a)P]) were injected ip to screen for mixed-function oxidase (MFO) activity. Chrysene, B(a)P, and Aroclor 1254 caused MFO induction. When fish were also exposed to solubilized pyrene, fluoranthene, and B(a)P in water, bioaccumulation of B(a)P resulted in MFO induction, whereas bioaccumulation of pyrene and fluoranthene did not. Based on water and injection exposure to B(a)P, it was predicted that tissue concentrations in excess of 300 micrograms/kg B(a)P would be accompanied by MFO induction in rainbow trout.

Animals↗
PubMed1979

Ascorbate anion potentiates cytotoxicity of nitro-aromatic compounds under hypoxic and anoxic conditions.

The nitro-aromatic radiosensitizing drugs are selectively toxic to hypoxic mammalian cells, and this toxicity can be greatly increased by the addition of ascorbate. The ascorbate itself is not toxic to either hypoxic or aerobic cells (as long as catalase is present to prevent the formation of significant concentrations of hydrogen peroxide) and the mixture of ascorbate plus radiosensitizer is not more toxic to aerobic cells. Sulphydryl reducing agents and dithionite have an effect opposite to ascorbate and decrease the toxicity of nitro-aromatic drugs under hypoxic conditions. Sulphydryl reducing agents are also reported to nullify the radiosensitizing properties of nitro-aromatic drugs, in contrast to ascorbate which has no effect on the radiosensitizing properties. The toxicity of nitro-aromatic drugs decreases rapidly with increasing O2 concentration. This decrease is much less rapid when ascorbate is present. The role of ascorbate in this case may be primarily as an O2 scavenger, although it is also possible that the toxic species produced by radiosensitizer-ascorbate mixtures is less easily removed or detoxified by O2.

Animals↗
PubMed1977

Polynitro aromatic compounds in analytical chemistry I: reaction with ouabain and digitoxin.

By the use of NMR spectroscopy, the highly colored reaction products formed by ouabain or digitoxin in with 1,3,5-trinitrobenzene or 2,4,6-trinitroanisole in the presence of alkali (as used for the determination of these glycosides) are shown to be Meisenheimer complexes. The complexes are produced by attachment of a carbon of the butenolide ring to an aromatic carbon of the nitro compound with formation of a charge-delocalized cyclohexadienate anion.

Anisoles↗
PubMed1977

Bis-basic-substituted polycyclic aromatic compounds. A new class of antiviral agents. 8. Bis-basic derivatives of carbazole, dibenzofuran, and dibenzothiophene.

A series of bisalkamine esters, bis-basic ethers, and bis-basic ketones of carbazole, N-ethylcarbazole, dibenzofuran, and dibenzothiophene was synthesized and evaluated for antiviral activity. The series also included two bis-basic alkanes of N-ethylcarbazole and one bis-basic carboxamide of dibenzofuran. Structure-activity relationships indicated that within the carbazole and N-ethylcarbazole series the bisalkamine esters gave the most active derivatives while the bis-basic ketone derivatives of dibenzofuran and dibenzothiophene afforded the more potent compounds within the respective series. The [6,5,6]heterocyclic nuclei were compared with the [6,5,6] aromatic nuclei (fluroene and fluoren-9-one) including tilorone with respect to antiviral activity against encephalomyocarditis (EMC) virus. Maximum activity was associated with the bis-basic ketone side chain and fluoren-9-one nucleus.

Animals↗
PubMed1976

Mutagenicity of K-region epoxides of polycyclic aromatic compounds: structure-activity relationship.

The mutagenicity of several K-region arene oxides was tested in histidine-dependent mutants of Salmonella typhimurium. Benzo(a)pyrene-4,5-oxide and pyrene-4,5-oxide as well as some substituted phenanthrene oxides were mutagenic in strains TA 1538 and TA 98 which detect frame-shift mutagens. Structure-activity relationships are discussed from the standpoint of chemical reactivity. The absence of direct correlation between electrophilic reactivity and mutagenicity may suggest that primilarily physical properties, such as relative position of the epoxide group and molecular shape of arene oxides, are important for the emergence of mutagenicity of arene oxides.

Benzopyrenes↗
PubMed1976

Mutagenicity and purative carcinogenicity tests of several polycyclic aromatic compounds associated with impurities of the insecticide methoxychlor.

Several polycyclic hydrocarbons, 3,6-dimethoxy-9,10-bis(p-methoxyphenyl)-phenathrene, tetrakis(p-methoxyphenylyethylene and 3,6,11,14-tetramethoxydibenzo(g,p)chrysene, which are associated as impurities in commerical samples of the insecticide methoxychlor, have been tested in the Ames mutagenicity test with strains of Salmonella thyphimurium, TA 1535, TA 1537, TA 1538, and TA 98. Activation by liver microsomes induced with either phenobarbitol or Aroclor was examined. The only active compound was 3,6,11,14-tetramethoxydibenzo(g,p)chrysene, mutagenic (0.39 revertants/nmol) tostrain TA 98.

Chrysenes↗
PubMed1978

Chemical structure and biodegradability of halogenate aromatic compounds. Substituent effects on 1,2-dioxygenation of benzoic acid.

Dioxygenation of substituted benzoic acids by whole cells of 3-chlorobenzoate-utilizing Pseudomonas sp. B 13, benzoate-induced cells of Alcaligenes eutrophus B 9 and toluate-grown cells of Pseudomonas putida mt-2 was examined. Electron-attracting substituents like halogen decreased the reaction rates of benzoate 1,2-dioxygenation. Dioxygenation of substituted benzoic acids by P. putida mt-2 was mostly undisturbed by steric effects of the substituents. Good correlation resulted between the log Vrel values and the Hammett substituent constant sigma. In contrast the reaction rates of dioxygenation by Pseudomonas sp. B 13 and A. eutrophus were decreased predominantly by steric effects of substituents. A non-polar reaction mechanism of benzoate 1,2-dioxygenation is discussed. Results from inhibition studies demonstrate high stereospecificities for the 1,2-dioxygenation by Pseudomonas sp. B 13 of benzoic acids with substituents in ortho- or para-position. In the case of P. putida mt-2 steric handrance by substituents was observed only with orth-substituted benzoic acids. Stereospecificities of the benzoate 1,2-dioxygenation by Pseudomonas sp. B 13 and P. putida mt-2 are illustrated schematically.

Bacteria↗
PubMed1978

Chemical structure and biodegradability of halogenated aromatic compounds. Substituent effects on dehydrogenation of 3,5-cyclohexadiene-1,2-diol-1-carboxylic acid.

The dehydrogenation of substituted 3,5-cyclohexadiene-1,2-diol-1-carboxylic acids by dihydrodihydroxybenzoic acid dehydrogenases from benzoate grown cells of Alcaligenes eutrophus and Pseudomonas sp. B 13 and 3-chlorobenzoate grown cells of the latter organism was examined. No significant differences (Km and Vrel values) were detected for the enzymes from both organisms. The same dihydrodihydroxybenzoic acid dehydrogenase is formed in Pseudomonas sp. B13 during growth on benzoate as well as on 3-chlorobenzoate. The lower turnover rates of 3- and 5-chlorodrodihydroxybenzoic acid compared to dihydrodihydroxybenzoic acid are counterbalanced by an increase in specific activity. With the exception of 4-substituted dihydrodihydroxybenzoic acids exhibiting relative high Km values, only slight sterical and electronic substituent effects are evident. Reaction rates were never reduced to a critical level.

Alcaligenes↗