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Effects of some disinfectants on African swine fever virus.

Ten commercially available disinfectants were tested at high pH in 2% sodium hydroxide and low pH in 2% acetic acid as inactivants for African swine fever (ASF) in a protein-rich blood-spleen homogenate. As assayed in leukocyte cultures, sodium hydroxide and acetic acid, sodium meta silicate and Roccal did not inactivate ASF virus in 1 hr at 22 to 25 C. Some viricidal activity as assayed in leukocyte cultures was found with Weladol, Triton X-100 Amphyl, pHisoHex, sodium dodecyl sulfate, LpH, Environ, Environ D, and One-Stroke Environ. Of these, the last four appeared to be most promising. When assayed in pigs, only One-Stroke Environ (1/E) was viricidal. Concentrations of 1.0, 0.75, and 0.5 were effective, but, at 0.25%, virus was not inactivated. The minimal time to inactivate ASF virus by 1% 1/E is 60 min. A room contaminated with ASF virus was made safe for pigs after 1 hr by spraying with 1% 1/E. The most active component of 1/E is o-phenylphenol. Although another component of 1/E, i.e., o-benzyl-p-chlorophenol, also has some activity, the mixture of the active components of 1/E is most effective against ASF virus. One of the soluble antigens associated with ASF virus is destroyed by 1/E.

Acetates↗

Metabolism of phenol and resorcinol in Trichosporon cutaneum.

Trichosporon cutaneum was grown with phenol or resorcinol as the carbon source. The formation of beta-ketoadipate from phenol, catechol, and resorcinol was shown by a manometric method using antipyrine and also by its isolation and crystallization. Metabolism of phenol begins with o-hydroxylation. This is followed by ortho-ring fission, lactonization to muconolactone, and delactonization to beta-ketoadipate. No meta-ring fission could be demonstrated. Metabolism of resorcinol begins with o-hydroxylation to 1,2,4-benzenetriol, which undergoes ortho-ring fission yielding maleylacetate. Isolating this product leads to its decarboxylation and isomerization to trans-acetylacrylic acid. Maleylacetate is reduced by crude extracts to beta-ketoadipate with either reduced nicotinamide adenine dinucleotide or reduced nicotinamide adenine dinucleotide phosphate as a cosubstrate. The enzyme catalyzing this reaction was separated from catechol 1,2-oxygenase, phenol hydroxylase, and muconate lactonizing enzyme on a diethyl-aminoethyl-Sephadex A50 column. As a result it was purified some 50-fold, as was the muconate-lactonizing enzyme. Methyl-, fluoro-, and chlorophenols are converted to a varying extent by crude extracts and by purified enzymes. None of these derivatives is converted to maleylacetate, beta-ketoadipate, or their derivatives. Cells grown on resorcinol contain enzymes that participate in the degradation of phenol and vice versa.

Adipates↗

2-aminophenol 1,6-dioxygenase: a novel aromatic ring cleavage enzyme purified from Pseudomonas pseudoalcaligenes JS45.

Most bacterial pathways for the degradation of aromatic compounds involve introduction of two hydroxyl groups either ortho or para to each other. Ring fission then occurs at the bond adjacent to one of the hydroxyl groups. In contrast, 2-aminophenol is cleaved to 2-aminomuconic acid semialdehyde in the nitrobenzene-degrading strain Pseudomonas pseudoalcaligenes JS45. To examine the relationship between this enzyme and other dioxygenases, 2-aminophenol 1,6-dioxygenase has been purified by ethanol precipitation, gel filtration, and ion exchange chromatography. The molecular mass determined by gel filtration was 140,000 Da. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed two subunits of 35,000 and 39,000 Da, which suggested an alpha2beta2 subunit structure. Studies with inhibitors indicated that ferrous iron was the sole cofactor. The Km values for 2-aminophenol and oxygen were 4.2 and 710 microM, respectively. The enzyme catalyzed the oxidation of catechol, 6-amino-m-cresol, 2-amino-m-cresol, and 2-amino-4-chlorophenol. 3-Hydroxyanthranilate, protocatechuate, gentisate, and 3- and 4-methylcatechol were not substrates. The substrate range and the subunit structure are unique among those of the known ring cleavage dioxygenases.

Aminophenols↗

Characterization of catechol catabolic genes from Rhodococcus erythropolis 1CP.

The biochemical characterization of the muconate and the chloromuconate cycloisomerases of the chlorophenol-utilizing Rhodococcus erythropolis strain 1CP previously indicated that efficient chloromuconate conversion among the gram-positive bacteria might have evolved independently of that among gram-negative bacteria. Based on sequences of the N terminus and of tryptic peptides of the muconate cycloisomerase, a fragment of the corresponding gene has now been amplified and used as a probe for the cloning of catechol catabolic genes from R. erythropolis. The clone thus obtained expressed catechol 1,2-dioxygenase, muconate cycloisomerase, and muconolactone isomerase activities. Sequencing of the insert on the recombinant plasmid pRER1 revealed that the genes are transcribed in the order catA catB catC. Open reading frames downstream of catC may have a function in carbohydrate metabolism. The predicted protein sequence of the catechol 1,2-dioxygenase was identical to the one from Arthrobacter sp. strain mA3 in 59% of the positions. The chlorocatechol 1,2-dioxygenases and the chloromuconate cycloisomerases of gram-negative bacteria appear to be more closely related to the catechol 1,2-dioxygenases and muconate cycloisomerases of the gram-positive strains than to the corresponding enzymes of gram-negative bacteria.

Amino Acid Sequence↗

Characterization of the maleylacetate reductase MacA of Rhodococcus opacus 1CP and evidence for the presence of an isofunctional enzyme.

Maleylacetate reductases (EC 1.3.1.32) have been shown to contribute not only to the bacterial catabolism of some usual aromatic compounds like quinol or resorcinol but also to the degradation of aromatic compounds carrying unusual substituents, such as halogen atoms or nitro groups. Genes coding for maleylacetate reductases so far have been analyzed mainly in chloroaromatic compound-utilizing proteobacteria, in which they were found to belong to specialized gene clusters for the turnover of chlorocatechols or 5-chlorohydroxyquinol. We have now cloned the gene macA, which codes for one of apparently (at least) two maleylacetate reductases in the gram-positive, chlorophenol-degrading strain Rhodococcus opacus 1CP. Sequencing of macA showed the gene product to be relatively distantly related to its proteobacterial counterparts (ca. 42 to 44% identical positions). Nevertheless, like the known enzymes from proteobacteria, the cloned Rhodococcus maleylacetate reductase was able to convert 2-chloromaleylacetate, an intermediate in the degradation of dichloroaromatic compounds, relatively fast and with reductive dehalogenation to maleylacetate. Among the genes ca. 3 kb up- and downstream of macA, none was found to code for an intradiol dioxygenase, a cycloisomerase, or a dienelactone hydrolase. Instead, the only gene which is likely to be cotranscribed with macA encodes a protein of the short-chain dehydrogenase/reductase family. Thus, the R. opacus maleylacetate reductase gene macA clearly is not part of a specialized chlorocatechol gene cluster.

Amino Acid Sequence↗

Evolutionary relationship between chlorocatechol catabolic enzymes from Rhodococcus opacus 1CP and their counterparts in proteobacteria: sequence divergence and functional convergence.

Biochemical investigations of the muconate and chloromuconate cycloisomerases from the chlorophenol-utilizing strain Rhodococcus opacus (erythropolis) 1CP had previously indicated that the chlorocatechol catabolic pathway of this strain may have developed independently from the corresponding pathways of proteobacteria. To test this hypothesis, we cloned the chlorocatechol catabolic gene cluster of strain 1CP by using PCR with primers derived from sequences of N termini and peptides of purified chlorocatechol 1,2-dioxygenase and chloromuconate cycloisomerase. Sequencing of the clones revealed that they comprise different parts of the same gene cluster in which five open reading frames have been identified. The clcB gene for chloromuconate cycloisomerase is transcribed divergently from a gene which codes for a LysR-type regulatory protein, the presumed ClcR. Downstream of clcR but separated from it by 222 bp, we detected the clcA and clcD genes, which could unambiguously be assigned to chlorocatechol 1,2-dioxygenase and dienelactone hydrolase. A gene coding for a maleylacetate reductase could not be detected. Instead, the product encoded by the fifth open reading frame turned out to be homologous to transposition-related proteins of IS1031 and Tn4811. Sequence comparisons of ClcA and ClcB to other 1,2-dioxygenases and cycloisomerases, respectively, clearly showed that the chlorocatechol catabolic enzymes of R. opacus 1CP represent different branches in the dendrograms than their proteobacterial counterparts. Thus, while the sequences diverged, the functional adaptation to efficient chlorocatechol metabolization occurred independently in proteobacteria and gram-positive bacteria, that is, by functionally convergent evolution.

Amino Acid Sequence↗

Illness associated with contamination of drinking water supplies with phenol.

In January 1984 the River Dee in north Wales was contaminated with phenol, with subsequent contamination of the tap water received by about two million consumers. A retrospective postal survey of 594 households was undertaken to determine whether consumption of this contaminated water was associated with illness. Subjects in areas that received contaminated water reported significantly more gastrointestinal illness than those in a nearby unexposed area (32.6% v 8.7%, p less than 0.00001) as well as reporting a higher incidence of any symptoms (43.6% v 18.4%, p less than 0.00001). Symptoms were consistent with phenol poisoning and bore a strong temporal relation to the pollution of the supply, but they developed at concentrations of phenols previously considered to be safe by the water authorities concerned. Chlorophenols produced during the treatment of water may have aggravated the problem.

Disease Outbreaks↗

Exposure to non-arsenic pesticides is associated with lymphoma among farmers in Spain.

OBJECTIVES: To estimate the risk of lymphoma among farmers in Spain. METHODS: This is a multicentre case control study conducted in Spain. Cases were subjects diagnosed with lymphoma according to the World Health Organization (WHO) classification in four hospitals between 1998-2002. Hospital controls were frequency matched to the cases by sex, age, and centre. All subjects were interviewed about jobs ever held in lifetime for at least one year and the exposures in those jobs were recorded. The risk of lymphomas among subjects ever having had a job as a farmer was compared with all other occupations. Farmers were analysed according to the type of farming job performed: crop farming, animal farming, and general farming. Occupational exposure was summarised into 15 main categories: organic dust, radiation, contact with animals, PAH, non-arsenic pesticides (carbamates, organophosphates, chlorinated hydrocarbons, triazines and triazoles, phenoxy herbicides, chlorophenols, dibenzodioxin, and dibenzofuran), arsenic pesticides, contact with meat, contact with children, solvents, asbestos, soldering fumes, organic colourants, polychlorinated biphenyls, ethylene oxide, and hair dyes. RESULTS: Although farmers were not at an increased risk of lymphoma as compared with all other occupations, farmers exposed to non-arsenic pesticides were found to be at increased risk of lymphoma (OR = 1.8, 95% CI 1.1 to 2). This increased risk was observed among farmers working exclusively either as crop farmers or as animal farmers (OR = 2.8, 95% CI 1.3 to 5.8). Risk was highest for exposure to non-arsenic pesticides for over nine years (OR = 2.4, 95% CI 1.2 to 2.8). CONCLUSIONS: Long term exposure to non-arsenic pesticides may induce lymphomagenesis among farmers.

Adult↗

Mortality and incidence of cancer at four factories making phenoxy herbicides.

To assess the possible carcinogenicity of phenoxy herbicides and related chlorophenols and dioxins, the International Agency for Research on Cancer is coordinating an international collaborative study of workers exposed to these compounds in their production or use. Four British cohorts of chemical manufacturers which have been recruited to the survey are described. They comprise a total of 2239 men employed during 1963-85. These subjects were traced to 31 December 1987 through the National Health Service Central Register and the National Insurance Index, and their mortality compared with that in the national population. Two deaths were from non-Hodgkin's lymphoma with 0.87 expected. Both deaths occurred more than 10 years after first exposure to phenoxy compounds. One further non-Hodgkin's lymphoma was registered in a living subject with probable exposure to phenoxy compounds. No cases of soft tissue sarcoma or Hodgkin's disease were recorded. A nonsignificant excess of lung cancer (19 deaths observed, 14.2 expected) is probably attributable to chance or a confounding effect of smoking. In one cohort only there was increased mortality from circulatory disease (34 deaths observed, 20.4 expected). A nested case-control study did not point to any occupational cause for this excess, but further evaluation will be needed during continued follow up.

Cardiovascular Diseases↗

Study of the reductive dechlorination of pentachlorophenol by a methanogenic consortium.

Pentachlorophenol (PCP) dechlorination by a methanogenic consortium was observed when glucose, formate, lactate, or yeast extract was present in the mineral medium as a secondary carbon source. Acetate was not a good substrate to sustain dechlorination. The consortium was able to dechlorinate the different monochlorophenols, although the chlorine in position ortho and meta was removed more readily than in para position. Dechlorination was most efficient at 37 degrees C. At 45 degrees C, the first PCP dechlorination steps were very rapid, but 3,5-dichlorophenol (3,5-DCP) was not further dechlorinated. At 15 and 4 degrees C, dechlorination was very slow. The dechlorination of PCP to 3-chlorophenol (3-CP) was still observed after the consortium had been subjected to heat treatment (80 degrees C, 60 min), suggesting that spore-forming bacteria were responsible. The dechlorinating activity of the consortium was significantly reduced by the presence of hydrogen, 2-bromoethanosulfonic acid (BESA), or sulfate but not of nitrate. The dechlorination of 3-CP was completely inhibited by heat treatment or the presence of BESA, suggesting that a syntrophic microorganism would be involved. Vigorous agitation of the consortium stopped the dechlorination, but the presence of DEAE-Sephacel acting as a support was very efficient in restoring the activity, suggesting that association between certain members of the consortium was important.

Alkanesulfonic Acids↗

Sulfur tuft and turkey tail: biosynthesis and biodegradation of organohalogens by Basidiomycetes.

Chlorinated aliphatic and aromatic compounds are generally considered to be undesirable xenobiotic pollutants. However, the higher fungi, Basidiomycetes, have a widespread capacity for organohalogen biosynthesis. Adsorbable organic halogens (AOX) and/or low-molecular-weight halogenated compounds are produced by Basidiomycetes of 68 genera from 20 different families. Most of the 81 halogenated metabolites identified from Basidiomycetes to date are chlorinated, although brominated and iodated metabolites have also been described. Two broad categories of Basidiomycete organohalogen metabolites are the halogenated aromatic compounds and the haloaliphatic compounds. Some of these organohalogen metabolites have demonstrable physiological roles as antibiotics and as metabolites involved in lignin degradation. Basidiomycetes produce large amounts of low-molecular-weight organohalogens or adsorbable organic halogens (AOX) when grown on lignocellulosic substrates. In our view, Basidiomycetes, as decomposers of forest litter, are a major source of natural organohalogens in terrestrial environments. Basidiomycetes are also potent degraders of a wide range of chlorinated pollutants, such as bleachery effluent from kraft mills and pentachlorophenol, polychlorinated dioxins, and polychlorinated biphenyls. The extracellular, lignin-degrading enzymes of the Basidiomycetes are involved in the oxidative degradation of chlorophenols and dioxin and can cause reductive dechlorination of halomethanes. There is no clear-cut separation between "polluters" and "clean-uppers" within the Basidiomycetes. Several genera, e.g. Bjerkandera, Hericium, Phlebia, and Trametes, produce significant amounts of chlorinated compounds but are also highly effective in metabolizing or biotransforming chlorinated pollutants.

Anti-Bacterial Agents↗

PAH transport in rock crab (Cancer irroratus) urinary bladder.

Crab urinary bladder appears to possess several morphological and functional similarities to vertebrate renal proximal tubule. Sections of intermolt rock crab bladder accumulated PAH by a process that was concentrative (60 min tissue-to-medium ratio (T/M) for 10 microM PAH averaged 24), Na dependent, powered by glycolytic metabolism, and inhibitable by other organic anions. Initial section uptakes exhibited saturation kinetics and a double-reciprocal plot of uptake vs. concentration yielded a single line with a Km of 70 microM and a Vmax of 5 nmol . mg tissue-1 . h-1. Chlorophenol red and bromocresol green (BCG) competitively inhibited PAH uptake. When bladder sheets were mounted in a flux chamber, they exhibited a large, net lumen-to-serosa (L leads to S) flux of 10 microM PAH that was abolished by 1 mM BCG. The small unidirectional S leads to L flux was not BCG-inhibitable. Bladder sheets exhibited PAH T/M greater than 1 after luminal, but not serosal, exposure. BCG only reduced bladder sheet T/M after luminal exposure. The data are consistent with uphill, Na-dependent, and carrier-mediated entry of PAH at the luminal membrane and nonmediated exit at the serosal membrane.

Aminohippuric Acids↗

Renal handling of the polar DDT metabolite DDA (2,2-bis[p-chlorophenyl] acetic acid) by marine fish.

The renal handling of 2,2-bis(p-chlorophenyl) acetic acid (DDA) was examined in the isolated tubules of the winter flounder (Pseudopleuronectes americanus) in vitro in conjunction with clearance studies in the flounder and in the aglomerular goosefish (Lophius americanus). In vitro, both uptake studies and autoradiography showed extensive energy-dependent accumulation within the cytoplasm of tubular cells and the tubular lumen. The uptake was strongly inhibited by p-aminohippurate and chlorophenol red. A second component of uptake was insensitive to metabolic inhibitors or organic acids and represented tissue binding. In vivo, both species showed net secretion which was inhibited by probenecid. Comparison of DDT and DDA distribution and excretion emphasized the importance of the greater water solubility of DDA and of its secretory transport, since DDA was excreted at over 200 times the rate of DDT. Liver, kidney, and bile also showed elevated DDA tissue-to-plasma ratios. Thus, the organic acid system mediates the accumulation and excretion of DDA in these fish.

Animals↗

Sulfate transport by flounder renal tubule brush border: presence of anion exchange.

Transport of sulfate into brush border membrane (BBM) vesicles from renal tubules of southern flounder, Paralichthys lethostigma, was investigated. Imposition of a 21 mM HCO-3 gradient, in greater than out, produced concentrative sulfate uptake (overshoot) fourfold higher than equilibrium. Gradient conditions were necessary to produce this response; no overshoot was produced by the mere presence of HCO-3. Generation of potassium diffusion potentials with KCl gradients and valinomycin or short-circuiting of possible other ionic diffusion potentials had no effect on sulfate uptake. The rate-limiting step in HCO-3:SO2-4 exchange is, therefore, an electroneutral process. Although HCO-3 was the most effective counterion for sulfate, SCN-, Cl-, and S2O2-3 were also capable of promoting concentrative sulfate uptake. Sulfate uptake in the absence of counterion and bicarbonate-dependent sulfate uptake were both shown to be saturable processes. HCO-3-driven sulfate uptake could be inhibited by disulfonic stilbene, HgCl2, probenecid, chlorophenol red, and bromcresol green. Phloridzin, p-aminohippuric acid, 2,4-dinitrophenol, isethionic acid, and citric acid had no significant effect on HCO-3:SO2-4 exchange. The role of this sulfate:anion exchanger in active renal tubule sulfate secretion is discussed.

Adenosine Triphosphatases↗

Kinetics of erythrocyte penetration by aliphatic acids.

The rate of entry of aliphatic acids into human red blood cells was studied using a new stopped-flow technique. Solutions of aliphatic acids and erythrocyte suspensions were rapidly mixed in a stopped-flow reaction apparatus. The change in extracellular pH resulting from entry of acid into the cell was monitored using chlorophenol red as an extracellular indicator. Extracellular pH of the mixture was linearly related to differential light transmission at 480 and 560 nm. Values of membrane permeability were fitted to data using a model of passive exchange with flux proportional to the transmembrane concentration gradient. At all temperatures the permeabilities were in the order: valeric acid greater than butyric acid greater than propionic acid. Permeabilities were highly temperature dependent and the activation energy (10.5 kcal/mol) remained constant between 7 and 37 degrees C. Despite rapid rates of exchange, permeability measurements did not exhibit evidence of artifact secondary to an unstirred solvent layer on the cell surface. The data are compatible with the hypothesis that aliphatic acid transport across the erythrocyte membrane is passive in nature and proportional to the transmembrane concentration gradient.

Butyrates↗

Biological inhibitory effects of the Chinese herb danggui on brain astrocytoma.

OBJECTIVE: Previous studies have demonstrated the utility of the traditional Chinese herb danggui in the treatment of chronic myelogenous leukemia. Our aim was to examine whether it might similarly be used to treat glioblastoma multiforme. METHODS: The lipid-soluble active ingredients of danggui were extracted with acetone (AS-AC) or chlorophenol (AS-CH) and their antiproliferative and proapoptotic effects were studiedin vitro on cultured GBM 8401 cells and in vivoon tumors in nude mice. RESULTS: After a 24-hour treatment, either AS-AC or AS-CH at a lower (50 micro g/ml) and a higher concentration (100 micro g/ml) significantly inhibited the proliferative activity of GBM 8401 cultured cells by 30-50%, as well as the expression of cathepsin B and vascular endothelial growth factor (VEGF). In nude mice, the growth of the tumor was inhibited by 30% by AS-CH or AS-AC (20 mg/kg; p < 0.05) and by 60% by AS-CH or AS-AC (60 mg/kg; p < 0.05). AS-AC and AS-CH also significantly inhibited microvessel formation in the tumors of nude mice. CONCLUSIONS: Danggui may inhibit tumor growth by reducing the level of VEGF and the proapoptotic protein, cathepsin B. Thus, danggui may be useful in the treatment of high-grade astrocytomas.

Adult↗

Human pentachlorophenol poisoning.

Pentachlorophenol (PCP) was, and still is, one of the most frequently used fungicides and pesticides. Its toxicity is due to interference with oxidative phosphorylation. Acute and chronic poisoning may occur by dermal absorption, inhalation or ingestion. Chronic poisoning occurs mainly in sawmill workers or people living in log homes treated with PCP-containing wood protecting formulations. Quantitative determination of PCP in urine and serum is useful to detect occupational or subclinical exposure. The clinical features of acute and chronic PCP poisoning can be classified systematically into effects on the skin, metabolism (fever), the haematopoietic tissue, the respiratory system, the central and peripheral nervous system, the kidney and the gastrointestinal tract. Although PCP is not classified as a human carcinogen, some epidemiological observations suggest that exposure to chlorophenols in general and PCP solutions in particular may result in an increased risk for certain malignant disorders such as nasal carcinoma and soft tissue sarcoma. There is concern that contamination of PCP-solutions with products such as chlorodibenzo-p-dioxins is the real cause of this suspected carcinogenicity. No specific antidote exists for the treatment of (acute) PCP poisoning. The basis of the treatment of acute poisoning is intensive supportive care with prevention of dangerous rise in temperature. Use of PCP-based products as indoor wood preservatives poses an unacceptable risk to human health.

Carcinogenicity Tests↗

[Monitoring of adipocyte responsiveness by in situ microdialysis in lipodystrophy tissue: adjustment of a glycerol quantification method in small samples].

In situ microdialysis allows monitoring of metabolic cellular processes at the tissue level in vivo. In the assessment of physiopathologic alterations seen in lipodystrophy, monitoring of glycerol release is pivotal. Indeed, it allows to quantify the pharmacological responsiveness of subcutaneous adipose tissue in humans. Until now, the small volume of microdialysate collected (5-15 microL/sample) restricted the assessment of glycerol level to the use of the radio-enzymatic method or the reference spectrophotometric microanalysis technique. The aim of this study was to adapt the method of glycerol measurement by iminequinone spectrophotometry colorimetric assay (520 nm) using the following reagent: 0.5 IU Glycerokinase, 1.23 IU glycerophosphate oxidase, 0.98 IU peroxidase, 4.6 mM Mg, 5.4 mM 4-chlorophenol, 0.25 mM 4-aminoantipyrine and 1.4 mM ATP. The assay was setup to run on Olympus AU 2700 automate (15 pL sample volume). The sensitivity of the method was improved by adding a 0.2 mmol triglyceride (TG) solution and 1.5 IU lipase to samples, reducing the limit of free glycerol quantification to 0.020 mmol/L. The analytical repeatability was 2.0% and the reproducibility was 7.9%. The present method thus demonstrated the feasibility of pharmacodynamic exploration of local cutaneous responsiveness in vivo in clinical trials.

Adipocytes↗