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At least 19 recordsLinked to original sources
PubMed1992

Bacteria that degrade p-chlorophenol isolated from a continuous culture system.

Two Gram-positive coryneform bacteria that degraded p-chlorophenol isolated from a continuous culture system are characterized. Isolate B (probably and Arthrobacter sp.) completely removed the p-chlorophenol from a medium with a concomitant increase in cell density within 16 h. Isolate F similarly removed the p-chlorophenol within 28 h but without an increase in cell density. Isolates B and F also removed the p-chlorophenol from a medium with p-chlorophenol as the sole carbon source within 32 and 48 h, respectively. The optimal temperature for p-chlorophenol degradation by both organisms was 25 to 30 degrees C. The optimal pH range for p-chlorophenol degradation was pH 7-9 for isolate B and pH 8-9 for isolate F. Since these native environmental bacteria can degrade p-chlorophenol, they may have an important application in waste water treatment processes.

Arthrobacter↗
PubMed1992

Reductive dehalogenation of chlorophenols by Desulfomonile tiedjei DCB-1.

Reductive dehalogenation of chlorophenols has been reported in undefined anaerobic cultures but never before in an anaerobic pure culture. We found that the sulfate-reducing bacterium Desulfomonile tiedjei DCB-1 reductively dehalogenates pentachlorophenol (PCP) and other chlorophenols. The maximum rate of PCP dechlorination observed was 54 mu mol of Cl- h-1 g of protein-1. 3-Chlorobenzoate appeared to serve as a required inducer for PCP dehalogenation; however, neither PCP nor 3-chlorophenol induced dehalogenation. Dehalogenation was catalyzed by living cells, and formate served as a required electron donor. D. tiedjei dehalogenated meta-chlorine substituents of chlorophenols (i.e., PCP was degraded to 2,4,6-trichlorophenol). Generally, more highly chlorinated phenol congeners were more readily dechlorinated, and 3-chlorophenol was not dehalogenated. Growing cultures dehalogenated PCP, but greater than 10 microM PCP (approximately 1.7 mmol g of protein-1) reversibly inhibited growth.

Bacteria, Anaerobic↗
PubMed1991

Biodegradation of 4-chlorophenol by adsorptive immobilized Alcaligenes sp. A 7-2 in soil.

Alcaligenes sp. A 7-2 immobilized on granular clay has been applied in a percolator to degrade 4-chlorophenol in sandy soil. Good adsorption rates on granular clay were achieved using cell suspensions with high titres and media at pH 8.0. The influence of various parameters such as aeration rate, pH, temperature, concentration of 4-chlorophenol and size of inoculum on the degradation rate were investigated. During fed-batch fermentations under optimal culture conditions, concentrations of 4-chlorophenol up to 160 mg.l-1 could be degraded. Semicontinuous culture experiments demonstrated that the degradation potential in soil could be well established and enhanced by the addition of immobilized bacteria. Continuous fermentation was performed with varying 4-chlorophenol concentrations in the feed and different input levels. The maximum degradation rate was 1.64 g.l-1.day-1.

Alcaligenes↗
PubMed1978

Influence of growth rate and nutrient limitation on the gross cellular composition of Pseudomonas aeruginosa and its resistance to 3- and 4-chlorophenol.

Concentrations of 3-chlorophenol and 4-chlorophenol below their minimal inhibitory concentrations were found to increase the permeability of Pseudomonas aeruginosa cells to protons. Levels of such activity were assessed in suspensions of cells prepared from chemostat-grown cultures, limited by either magnesium (Mg-lim) or glucose (G-lim), with the use of five growth rates. Drug concentrations required to produce the same levels of proton translocation varied with the growth rate and the nutrient limiting growth. Fast-growing cultures were more sensitive than slower-growing ones, and G-lim cells were generally more sensitive than Mg-lim ones. 3-Chlorophenol had greater activity than 4-chlorophenol at slow growth rates, but at faster rates of growth their activity was similar. Variation in these iso-effective concentrations for different cells probably reflected an alteration in the ease of drug penetration of the outer envelope. Uptake of the compounds by cells in suspension varied, drug-sensitive bacteria absorbing more than resistant ones. This variation in uptake persisted when bacteria were solvent-extracted to remove readily extractable lipids (REL). Since no significant alteration in cell size was observed among the growth conditions studied, variation in absorption probably resulted from an altered affinity of the cells to the drug, with little involvement of REL. Overall REL content did not alter significantly with growth rate or nutrient limitation. However, total phospholipid content decreased and fatty acid content increased with increasing growth rate. For G-lim and Mg-lim cultures phosphatidylcholine content remained constant, yet phosphatidylethanolamine and phosphatidylglycerol content decreased with increasing growth rate. Diphosphatidylglycerol content decreased with increasing growth rate for Mg-lim cultures and remained relatively constant for G-lim cultures. Lipopolysaccharide content of the cells was higher in Mg-lim than in G-lim cultures and decreased with increasing growth rate in both cases. Lipopolysaccharide content correlated significantly with drug uptake and sensitivity, and it appeared to determine the degree of penetration of the cell envelope by these chlorinated phenols.

Chlorophenols↗
PubMed1992

Phenoxy herbicides and chlorophenols: a case control study on soft tissue sarcoma and malignant lymphoma.

A case control study on patients with soft tissue sarcoma and malignant lymphoma was undertaken to test whether there was any association between these diseases and past exposure to chlorinated phenoxy acid herbicides or chlorophenols. It was carried out over the period 1982-1988 in Victoria, Australia. Thirty males with soft tissue sarcoma and 52 males with malignant lymphoma were matched by age, place of residence and sex with one population control and one cancer control each. Exposure was assessed by personal interviews conducted by an occupational hygienist. Exposures within 5 years prior to diagnosis of each matched case were ignored, both for the cases and their matched controls. The estimated relative risks for definite or probable exposure to chlorinated phenoxy compounds or chlorophenols for at least 1 day were 1.0 (95% confidence interval (CI): 0.3-3.1) for soft tissue sarcoma and 1.5 (95% CI: 0.6-3.7) for malignant lymphoma. When the criterion for exposure was raised to more than 30 days, the estimated relative risks were 2.0 (95% CI: 0.5-8.0) for soft tissue sarcoma and 2.7 (95% CI: 0.7-9.6) for malignant lymphoma. Additional analyses were carried out for exposure of at least 1 day to phenoxy herbicides alone or chlorophenols alone. None of the estimated relative risks was significantly greater than unity.

Adult↗
PubMedDate not supplied

Cancer incidence following chlorophenol exposure in a community in southern Finland.

Chlorophenols have contaminated the drinking water system and the local lake in the village of Järvelä in southern Finland. Local geology, ground water streams, and chemical analyses incriminated a local sawmill as the only plausible source of exposure. Cancer incidence in the municipality of Kärkölä (half of the population lives in Järvelä), compared with the rest of the local health-care district and with the greater cancer control region, indicated an excess of soft-tissue sarcomas and non-Hodgkin's lymphomas. A case-control study, which focused on cancers of the colon, bladder and soft tissues, lymphomas, and leukemia, demonstrated a significantly elevated risk ratio for non-Hodgkin's lymphomas among persons who consumed fish from the local lake, which was contaminated with chlorophenols. Probable exposure to chlorophenol-contaminated drinking water played a role in the increased incidence of non-Hodgkin's lymphomas and possibly was a factor in the development of soft-tissue sarcoma.

Animals↗
PubMed1976

Use of chlorophenols as fungicides in sawmills.

Several commercial formulations of chlorophenols used as fungicides in sawmills were found to contain impurities, some of which are known to be much more toxic than the main products. The most frequent impurities were chlorinated phenoxyphenols, chlorinated diphenyl ethers, chlorinated dibenzofurans, and chlorinated dibenzodioxins. Samples of wood dust from several positions in two Swedish sawmills were analyzed. The results suggest that the impurities in the chlorophenol formulations are enriched in the work environment in relation to the chlorophenols themselves, probably because of the low volatility and high chemical stability of the impurities. The effect of various methods of fungicide application on the work environment is discussed.

Fungicides, Industrial↗
PubMed1977

Disturbance of microsomal detoxication mechanisms in liver by chlorophenol pesticides.

The pesticide pentachlorophenol known as an uncoupler of mitochondrial oxidative phosphorylation was shown to disturb liver microsomal detoxication functions by a selective inhibition of the terminal oxygenation enzyme P-450. At lower concentrations the flavin moiety of this enzyme chain is not inhibited but rather is stimulated, whereby a qualitative shift in detoxication of aromatic amines from C-oxygenation to N-oxygenation is obtained. The effects were due to the pentachlorophenol itself and not to a metabolite. Similar effects of varying strength were also obtained with other chlorophenol pesticides; 2,4,di-, 2,4,6,-tri and 2,3,4,6-tetrachlorophenol, di- and hexachlorophen, tri- and nonachloro-2-hydroxydiphenyl ethers. The relevance of these findings to the possible synergistic influence of chlorophenols on the carcinogenic effects of polyaromatic amines and hydrocarbons is discussed.

Aniline Compounds↗
PubMed1979

Case-control study: soft-tissue sarcomas and exposure to phenoxyacetic acids or chlorophenols.

In 1977 a number of patients with soft-tissue sarcomas and previous exposure to phenoxyacetic acids were described. Following from these observations a matched case-control study was made. Exposure to chlorophenols was also included in this study. The results showed that exposure to phenoxyacetic acids or chlorophenols gave an approximately 6-fold increase in the risk for this type of tumour. It was not possible to determine, however, whether the carcinogenic effect was exerted by these compounds or by impurities such as chlorinated dibenzodioxins and dibenzofurans that in almost all cases were part of the commercial preparations.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1992

The anaerobic degradation of 3-chloro-4-hydroxybenzoate in freshwater sediment proceeds via either chlorophenol or hydroxybenzoate to phenol and subsequently to benzoate.

To study the anaerobic degradation of the chimera 3-chloro-4-hydroxybenzoate (3-Cl,4-OHB), anaerobic freshwater sediment samples from the vicinity of Athens, Ga., were adapted for the transformation of 4-hydroxybenzoate (4-OHB), 3-chlorobenzoate (3-CB), 2-chlorophenol (2-CP), and 2,4-dichlorophenol (2,4-DCP). In nonadapted samples, both 4-OHB (product of aryl dechlorination) and 2-CP (product of aryl decarboxylation) were observed as intermediates in the transformation of 3-Cl,4-OHB to phenol. The accumulated phenol was subsequently transformed to benzoate, an intermediate in the conversion to methane and CO2. In 4-OHB-adapted samples (i.e., samples adapted for aryl decarboxylation), 2-CP was the first intermediate which was subsequently dechlorinated to phenol. In 3-CB-adapted samples (i.e., samples adapted for meta-chlorobenzoate dehalogenation), 3-Cl,4-OHB was stoichiometrically dechlorinated to 4-OHB. In 2-CP-adapted samples (i.e., samples adapted for ortho-chlorophenol dehalogenation), 4-OHB was the first major intermediate. Furthermore, 3-CB was not dechlorinated in 2-CP-adapted sediment samples, suggesting the possibility that different 3-Cl,4-OHB dechlorinating systems were induced in the 2-CP- and 3-CB-adapted sediments. Adaptation of sediment samples for dechlorination of 2,4-DCP did not lead to adaptation for dechlorination of 3-Cl,4-OHB. However, 3-Cl,4-OHB was dechlorinated to 4-OHB in our stable, sediment-free 2,4-DCP-dechlorinating enrichment, isolated previously from the same environment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Biological↗
PubMed1992

Limited degradation of chlorophenols by anaerobic sludge granules.

To better understand the fate of chlorophenols treated in upflow anaerobic sludge bed reactors, we examined the ability of sludge granules from such bioreactors to degrade two trichlorophenols and one dichlorophenol in batch incubations under controlled conditions. Biodegradation was primarily limited to two distinct activities, reductive dehalogenation of ortho- and of meta-chlorine substituents. Both 3- and 4-monochlorophenol were persistent degradation products, while 2-monochlorophenol was further degraded. We also examined factors potentially affecting the rate and extent of 2,3,6-trichlorophenol degradation. An initial concentration of up to 1.75 mM (346 mg/liter) was dehalogenated. At that concentration, dehalogenation was partially inhibited but methanogenesis from formate was not. The initial concentration affected both the extent of dehalogenation and which products were detected. The maximum dechlorination rate observed was 1.4 mumol of Cl- h-1 g of volatile suspended solids-1. Dechlorination had a temperature optimum of 50 degrees C, was inhibited by added electron acceptors, and was not appreciably affected by added electron donors. The availability of electron acceptors and electron donors did not affect the extent of chlorophenol degradation. These particular sludge granules do not appear to be capable of mineralizing phenols with meta- or para-chlorine substituents.

Anaerobiosis↗
PubMed1992

Effect of cosubstrates on the dechlorination of selected chlorophenolic compounds by Rhodococcus erythropolis 1CP.

Effects of aromatic and nonaromatic cosubstrates on the rate of 2,4-dichlorophenol degradation by R. erythropolis 1CP were studied under growth and nongrowth conditions. Glucose and maltose were found to accelerate 2,4-dichlorophenol (initial conc. 50 mg/l) dechlorination from 11 days to 24 and 20 h, respectively. The stimulating effect was observed within the range of glucose concentration of 0.5-2.0 g/l in the medium. Ascorbic acid at a concentration of 10-70 mg/l as a nongrowth substrate also increased the decomposition of 2,4-dichlorophenol, though at a lower degree than glucose. Experiments with washed cells showed the limiting stage of chlorophenol degradation by R. erythropolis 1CP to be, possibly, aromatic ring dechlorination after its hydroxylation. As an additional source of electrons, glucose introduced into suspensions of washed cells grown on 3-hydroxybenzoate made it possible to eliminate the bottleneck in 2,4-dichlorophenol metabolism by significantly accelerating dechlorination of 3,5-dichlorocatechol. Based on the experimental and literature data, the enzyme systems involved in 2,4-dichlorophenol degradation by the culture R. erythropolis 1CP are assumed to be nonspecific.

Biodegradation, Environmental↗
PubMed1992

The conformational behaviour of complexes of alpha-cyclodextrin with p-chlorophenol and p-hydroxybenzoic acid in water as studied by molecular dynamics simulations.

Molecular dynamics simulations were performed to obtain information about the conformational behaviour and stabilization of alpha-cyclodextrin (alpha CD) complexes in water. Simulations of p-chlorophenol and p-hydroxybenzoic acid in alpha CD showed that the complex is a very flexible system. The guest compound rotates inside the cavity and partly moves in and out. alpha CD continuously adapts its conformation to the orientation of the guest compound (or vice versa): the hexagon of the glycosidic oxygen atoms is stretched parallel to the plane of the aromatic ring of the guest compound during 80% of the simulation. This suggests that Van der Waals interactions play an important role in the stabilization of the complex. Each intramolecular hydrogen bond between neighbouring glucose units is formed during 30-80% of the simulation. Hydrogen bonds between alpha CD and the guest compound, on the other hand, are rarely formed. Thus, intermolecular hydrogen bonding seems to play a minor role in the stabilization of alpha CD complexes.

Chlorophenols↗
PubMed1992

Isolation of Pseudomonas pickettii strains that degrade 2,4,6-trichlorophenol and their dechlorination of chlorophenols.

Three strains of Pseudomonas pickettii that can grow with 2,4,6-trichlorophenol (2,4,6-TCP) as the sole source of carbon and energy were isolated from different mixed cultures of soil bacterial populations that had been acclimatized to 2,4,6-TCP. These strains released 3 mol of chloride ion from 1 mol of 2,4,6-TCP during the complete degradation of the TCP. Of these strains, P. pickettii DTP0602 in high-cell-density suspension cultures dechlorinated various chlorophenols (CPs). Cells that were preincubated with 2,4,6-TCP converted isomers of 4-CP to the corresponding chloro-p-hydroquinones, but those preincubated with 4-CP converted CPs lacking a chlorine atom(s) at the o position to isomers of chlorocatechol. The ability of DTP0602 to dechlorinate 2,4,6-TCP was induced by 2,6-dichlorophenol, 2,3,6- and 2,4,6-TCP, and 2,3,4,6-tetrachlorophenol and was repressed in the presence of succinate or glucose.

Biodegradation, Environmental↗
PubMed1992

Reductive dechlorination of chlorophenols by a pentachlorophenol- acclimated methanogenic consortium.

Anaerobic digester sludge fed 5,300 mg of acetate per liter, 3.4 microM pentachlorophenol, and nutrients for 10 days biotransformed pentachlorophenol by sequential ortho dechlorinations to produce 2,3,4,5-tetrachlorophenol and 3,4,5-trichlorophenol. Upon acclimation to 3.4 microM pentachlorophenol for 6 months, the methanogenic consortium removed chlorines from the ortho, meta, and para positions of pentachlorophenol and its reductive dechlorination products. Pentachlorophenol was degraded to produce 2,3,4,5-tetrachlorophenol, 2,3,4,6-tetrachlorophenol, and 2,3,5,6-tetrachlorophenol. Dechlorination of 2,3,4,5-tetrachlorophenol produced 3,4,5-trichlorophenol, which was subsequently degraded to produce 3,4-dichlorophenol and 3,5-dichlorophenol. 2,3,4,6-Tetrachlorophenol was dechlorinated at the ortho and meta positions to produce 2,4,6-trichlorophenol and 2,4,5-trichlorophenol. 2,3,5,6-Tetrachlorophenol yielded 2,3,5-trichlorophenol, followed by production of 3,5-dichlorophenol. 2,4,6-Trichlorophenol was degraded to form 2,4-dichlorophenol, and 2,4,5-trichlorophenol was dechlorinated at two positions to form 2,4-dichlorophenol and 3,4-dichlorophenol. Of the three dichlorophenols produced (2,4-dichlorophenol, 3,4-dichlorophenol, and 3,5-dichlorophenol), only 2,4-dichlorophenol was degraded significantly within 3 weeks, to produce 4-chlorophenol.

Adaptation, Physiological↗
PubMed1992

In vitro activity of taurolidine, chlorophenol-camphor-menthol and chlorhexidine against oral pathogenic microorganisms.

The antimicrobial activity of taurolidine (Taurolin, CAS 19388-87-5), a synthetic broad-spectrum antimicrobial agent and anti-toxin, and two conventional antiseptics, chlorophenol-camphor-menthol (CCM) and chlorhexidine digluconate (CHX) were compared using the serial dilution test on 10 potential oral pathogenic bacterial species. The minimum inhibitory and minimum bactericidal concentrations were lowest for CHX (MIC 0.03-0.12 mg/ml), followed by taurolidine (MIC 0.12-0.5 mg/ml) and CCM (MIC 0.5-2.0 mg/ml). However, if both bacterial efficacy and cytotoxicity are considered, only taurolidine achieves extensive bactericidal activity with tissue tolerability.

Anti-Infective Agents, Local↗
PubMed1975

Urinary metabolites from gamma- and beta-BHC in the mouse: chlorophenol conjugates.

Metabolites produced from gamma- and beta-BHC in the mouse urine were purified and characterized. Most metabolites from both isomers were not extractable by non-polar organic solvents and were conjugates such as sulfates and glucuronides. After hydrolysis with an appropriate enzyme, the conjugates gave chlorophenols, among which 2,4,6-trichlorophenol existed most abundantly (total, about 25% in the urine metabolites). 2,4-Dichlorophenol also constituted a significant portion.

Animals↗