Fungal bioconversion of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP).

Ninety strains of fungi from the collection of our mycology laboratory were tested in Galzy and Slonimski (GS) synthetic liquid medium for their ability to degrade the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and its by-product, 2,4-dichlorophenol (2,4-DCP) at 100 mg l(-1), each. Evolution of the amounts of each chemical in the culture media was monitored by HPLC. After 5 days of cultivation, the best results were obtained with Aspergillus penicilloides and Mortierella isabellina for 2,4-D and with Chrysosporium pannorum and Mucor genevensis for 2,4-DCP. The data collected seemed to prove, on one hand, that the strains responses varied with the taxonomic groups and the chemicals tested, and, on the other hand, that 2,4-D was less accessible to fungal degradation than 2,4-DCP. In each case, kinetics studies with the two most efficient strains revealed that there was a lag phase of 1 day before the onset of 2,4-D degradation, whereas there was none during 2,4-DCP degradation. Moreover, 2,4-DCP was detected transiently during 2,4-D degradation. Finally, M. isabellina improved its degradation potential in Tartaric Acid (TA) medium relative to GS and Malt Extract (ME) media.

A quantitative structure-activity relationship study on substituted pyridines as a contribution to the knowledge of the toxic effects of orellanine, a toxin from the mushroom Cortinarius orellanus.

Quantitative structure-activity relationships are established based upon the toxicity of 21 substituted pyridines. They are used as a predictive tool to calculate the toxicity of orellanine, a toxin from the mushroom Cortinarius orellanus (Fries). The actual toxicity of orellanine is quite different from the values calculated based upon the postulated bipyridine structure. The exact structure of orellanine may be questioned. However, our results show that even slight variations of the substituents of pyridines may cause dramatic changes of toxicity.

Orellanine inhibits protein synthesis in Madin-Darby canine kidney cells, in rat liver mitochondria, and in vitro: indication for its activation prior to in vitro inhibition.

Pure orellanine, a nephrotoxic compound extracted from the mushroom Cortinarius orellanus, which is known to induce severe kidney damage several days or weeks after ingestion, is found to inhibit strongly the synthesis of macromolecules (proteins, RNA and DNA) in Madin-Darby canine kidney (MDCK) cells and in rat liver mitochondria, although the uptake of labelled precursors of the above macromolecules is not significantly altered. Direct addition of orellanine to a cell-free system of rabbit reticulocyte lysate does not produce any inhibition of protein synthesis. However, when orellanine is pre-incubated with activating rat liver microsomal systems, this inhibition occurs. Thus, the in vivo inhibition of protein synthesis is most likely due to a metabolite of orellanine.

Hazard to man and the environment posed by the use of urban waste compost: a review.

This review presents the current state of knowledge on the relationship between the environment and the use of municipal waste compost in terms of health risk assessment. The hazards stem from chemical and microbiological agents whose nature and magnitude depend heavily on the degree of sorting and on the composting methods. Three main routes of exposure can be determined and are quantified in the literature: (i) The ingestion of soil/compost mixtures by children, mostly in cases of pica, can be a threat because of the amount of lead, chromium, cadmium, PCDD/F and fecal streptococci that can be absorbed. (ii) Though concern about contamination through the food chain is weak when compost is used in agriculture, some authors anticipate accumulation of pollutants after several years of disposal, which might lead to future hazards. (iii) Exposure is also associated with atmospheric dispersion of compost organic dust that convey microorganisms and toxicants. Data on hazard posed by organic dust from municipal composts to the farmer or the private user is scarce. To date, microorganisms are only measured at composting plants, thus raising the issue of extrapolation to environmental situations. Lung damage and allergies may occur because of organic dust, Gram negative bacteria, actinomycetes and fungi. Further research is needed on the risk related to inhalation of chemical compounds.

Relationship between the biodegradative capability of soil micromycetes for pentachlorophenol and for pentachloronitrobenzene.

A collection of 1056 strains in our laboratory were incubated with various xenobiotics among which were two potent fungicides: pentachlorophenol (PCP) and pentachloronitrobenzene (PCNB). The production of extracellular phenoloxidases were examined, using a series of ten different reagents. On the whole, PCNB is less accessible to fungal degradation than PCP. Although no correlation was found between the biodegradative capability of individual fungal strains for PCP or for PCNB, when taxonomic groups were considered as a whole, the same activity profiles were found. Zygomycetes were the most efficient; yeasts the least efficient towards both substrates. A more detailed study of the metabolism of both substrates on selected strains is in progress.

Biodegradation of anthracene by soil fungi. Groupe pour l'Etude du Devenir des Xénobiotiques dans l'Environnement (GEDEXE).

A selection of 39 strains of micromycetes known as good degraders of polychlorinated aromatic compounds, mostly isolated from soil and belonging to various taxonomic groups, have been investigated for anthracene degradation. Toxicity and consumption assays, first evaluated on solid media, have not shown any toxicity of anthracene (1-100 mg.L-1) towards fungi. Degradation of anthracene (10 mg.L-1) was then investigated in a liquid synthetic medium for 4 days and evaluated by HPLC. Among the 39 strains tested, 19 degraded anthracene at 50% or more. Zygomycetes appeared to be the most efficient group (mean degradation : 81%) while Melanconiales were the least efficient (mean: 14%). Among 19 efficient strains, 8 had not yet been reported in the literature: Cryphonectria parasitica, Ceriporiopsis subvermispora, Oxysporus sp., Cladosporium herbarum, Drechslera spicifera, Verticillium lecanii, Fusarium moniliforme var. subglutinans and Rhizopus arrhizus.

Effects of culture parameters on the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) by selected fungi. Groupe pour l'Etude du Devenir des Xénobiotiques dans l'Environnement (GEDEXE).

In order to enhance 2,4-D and 2,4-DCP degradation by four selected fungi (Cunninghamella elegans, C. echinulata, Rhizoctonia solani and Verticillium lecanii), three culture parameters (initial chemical concentration, amounts of glucose and nitrogen) were varied. The levels of both xenobiotics in the culture media were monitored by HPLC analysis after five days of cultivation. The best results were obtained at low initial concentration (20 mg.L-1 vs 100) and with low amounts of glucose (5 g.L-1 vs 10) and nitrogen (2.4 mM vs 24). When these two elements were lacking from the culture media, biodegradation was not suppressed, but took place to a lesser extent. Thus, initial chemical concentration and amounts of carbon and nitrogen, in the culture medium, were shown to strongly influence the extent of 2,4-D and 2,4-DCP removal by fungi.

Biodegradation of fluoranthene by soil fungi.

A selection of 39 strains of micromycetes known as good degraders of polychlorinated aromatic compounds, mostly isolated from soil and belonging to various taxonomic groups, have been investigated for fluoranthene degradation. Toxicity assays, first evaluated on solid medium MEA, have not shown any toxicity of fluoranthene (1-100 mg.L-1) towards fungi. Whereas, consumption assays on a solid synthetic medium showed a toxicity at 100 mg.L-1. The degradation of fluoranthene (10 mg.L-1) was then investigated in a liquid synthetic medium for 4 days and evaluated by HPLC. Among the 39 strains tested, 18 degraded fluoranthene at 60% or more. Zygomycetes appeared to be the most efficient group (mean degradation: 90%). Among 18 performant strains, 10 had not yet been reported in the literature: Sporormiella australis, Cryptococcus albidus, Cicinobolus cesatii, Pestalotia palmarum, beauveria alba, Aspergillus terreus. Cunninghamella blakesleeana, C. echinulata, Mortierella ramanniana and Rhizopus arrhizus. Fluoranthene adsorption on fungi was very low for the strains which degraded well fluoranthene (mean adsorption: 4%). Whereas, some strains adsorbed it much more such as Colletotrichum dematium (47%) and Penicillium italicum (43%).

Biodegradation of three substituted phenylurea herbicides (chlortoluron, diuron, and isoproturon) by soil fungi. A comparative study.

As a part of a study conducted on the fate of xenobiotics in the environment, a selection of 90 strains of micromycetes, mostly isolated from soil and belonging to various taxonomic groups, have been cultivated in liquid synthetic medium with chlortoluron (100 mg.L-1), diuron (20 mg.L-1), and isoproturon (100 mg.L-1) for 5 days. Evaluation of the chemicals in the culture media was made by HPLC. Our results show a wide variation not only with taxonomic groups but also with the species, and with the tested chemicals. On the whole, 4, 7, and 11% of the strains depleted respectively chlortoluron, diuron, and isoproturon, at 50% or over. Rhizoctonia solani was the only strain that depleted each of the 3 substituted phenylureas over 70%, nevertheless, the growth of this fungus was slightly inhibited by diuron. The very fast disappearance of the chemicals from the culture media was only due to biotic phenomena, as no adsorption occurred on the fungal biomass. So, depletion translated a real biodegradation of the tested substrates.

Liquid chromatography study of pyrene degradation by two micromycetes in a freshwater sediment.

Pyrene biodegradation in a freshwater sediment without fungi supply, or inoculated with two sediment micromycetes, Mucor racemosus var. sphaerosporus and Phialophora alba was studied after 0, 5, 13, 28, 60 and 90 days. The influence of glucose addition was estimated, and a liquid chromatographic method for simultaneous quantitative determination of residual anthracene, fluoranthene and pyrene in the sediment was developed. Samples with PAHs were extracted in Soxhlet with ethyl acetate, and LC analysis was performed on a 5 microm Supelcosil column (150 x 4.6 mm I.D.) with gradient elution (2 ml min(-1)) of acetonitrile-water and UV detection at 254 nm. Recoveries of anthracene, fluoranthene and pyrene were 90.3%+/-1.1%, 93.2%+/-0.9% and 90.42%+/-1.9%, respectively, without interference. The native sediment microorganisms (with or without glucose added) have shown 35% pyrene degradation and sediment with glucose inoculated by the strains revealed 40%.

GABA transaminase inhibitors.

In summary, several branched-chain fatty acids appeared to be competitive inhibitors of GABA-T and non-competitive inhibitors of SSADH. These compounds produce an increase in brain GABA level, and for two of these it was shown that the increase differs among various brain areas. An increase of GABA cannot be obtained by inhibition of SSADH. The increase in brain GABA seems to correlate with the anticonvulsant activity of branched-chain fatty acids.

Diversity in phenol-metabolizing capability of 809 strains of micromycetes.

The property of 809 strains of micromycetes to grow in the presence of phenol (0.5 g/l) was investigated on solid media. Toxicity was determined on malt extract agar medium. Growth of the fungal strains on synthetic solid medium with phenol as the sole carbon source allowed evaluation of phenol consumption. Only 61 strains (8% of the whole) grew well under both conditions, which reflects the toxicity of 0.5 g/l of phenol upon micromycetes. Finally, Phanerochaete chrysosporium was chosen and cultivated in liquid synthetic medium at 24 degrees C and 37 degrees C with phenol (0.5 g/l). It consumed phenol fast and efficiently. Growth temperature was a key parameter. Catechol, cis-cis-muconic acid and beta-keto-adipate were characterized and quantified.

Influence of environmental adaptation on the sensitivity of micromycetes to pentachlorophenol toxicity in microcosms.

The search for fungal strains capable of pentachlorophenol degradation led to the isolation and identification of 98 different micromycetes. When these strains were submitted to toxicity tests in aquatic microcosms at concentrations of 10 mgL-1 and 100 mgL-1 PCP, inhibition of growth was 57% and 36% respectively of the total isolated and identified strains. Among the strains inhibited at 10 mgL-1, 6 can serve as bioindicators of PCP pollution while the strains resistant can be regarded as potential PCP biodegraders. It was confirmed that fungal strains isolated from sites contaminated by chemically different products manifest different levels of sensitivity to PCP toxicity and probably different biodegradation potentials.

[Meta-analysis and dose-response functions of air pollution respiratory effects]. / Méta-analyse et fonctions dose-réponse des effets respiratoires de la pollution atmosphérique.

A Meta-analysis was conducted on 107 original epidemiological papers published between 1980 and 1993 on the respiratory health impact of suspended particles, sulfur dioxide, ozone and nitrogen dioxide. These are the usual air quality indicators that are monitored in urban ambient air. The range of exposures that were studied (averages and 90th percentiles are respectively up to 88, 83, 124 and 53 mu/m3 (averages) and 180, 147, 234 and 131 micrograms/m3 (90th percentile) for each of the four pollution indicators) allowed assessment of dose-response functions for irritative pulmonary conditions (cough and/or asthma episodes) and respiratory function (FEVI and peak expiratory flow). The dose-response functions seem linear in the range of observed concentrations, with nitrogen dioxide showing the least consistent association across different health indicators. When applied to exposures measured as a 100 micrograms/m3 increase of pollutant's concentrations compared to low background values, the average relative risks of airway irritation (cough and/or asthma épisodes) range, according to the pollutant, from 1.08 to 1.47; average relative decreases of respiratory function amount to 1.1 to 2.2%. The effects are most often stronger among young subjects. The results of this study, when applied to air pollution concentrations in the range of values that were observed in this study, should foster health risk assessment studies in places where population air pollution exposures are available.

Evaluation of acrodontiolamide, a chlorinated compound produced by Acrodontium salmoneum de Hoog for cytotoxicity and antimicrobial activity.

A new antifungal compound has been isolated from the culture medium of Acrodontium salmoneum de Hoog. Its structure was previously elucidated and was named acrodontiolamide. However, this compound is not characteristically produced by the genus Acrodontium, it is rather a feature of one isolate of A. Salmoneum coming from the soil of the grotto of La Pierre Saint Martin (France). Production, purification, cytotoxicity and antimicrobial activities of acrodontiolamide are described. Concerning microorganisms, inhibitory activity seems to be specifically restricted to phytopathogenic and entomapathogenic fungi. Acrodontiolamide is not cytotoxic to either normal human cultured cells or tumor cells.

Antitumor activity of patulin and structural analogs.

A comparison between the cytotoxicity and the antitumor activity of patulin and five structural analogs (isopatulin, dehydroisopatulin, dimethylisopatulin, trimethylisopatulin and isopropylisopatulin) has been established. In vitro assays using L 1210 and P 388 cells showed that the structure of the pyranic ring as well as the nature of the substituents influenced the observed activities. Among the five structural analogs of patulin assayed in vivo against Ehrlich carcinoma, L 1210 and P 388 leukemias, dehydroisopatulin was the only one to be active on all 3 types of tumors at a dose of 100 mg.kg-1.d-1. The ratio between the LD50 in mice and the active dose was 5 while with patulin it was 10. It can be assumed that the lactone function is not solely responsible for the activity of patulin and its structural analogs.

Antitumoral activity of patulin and patulin-cysteine adducts.

A comparison between the cytotoxicity and the anti-tumoral activity of patulin and patulin-cysteine adducts has been conducted. In vitro assays using L 1210 and P 388 cells showed that patulin-cysteine adducts had less cytotoxic activity than patulin (IC50 was 4 fold of IC50 patulin). In vivo, cysteine not only reduced the toxicity of patulin but also reduced its antitumoral activity against L 1210 and P 388 mouse leukemias (respectively of 25.7% and 46.6% with 3 mg.kg-1.d-1). By addition on patulin at the 4 or 7 position, cysteine might interfere with the lactone function and the -CH2- in in position 6 which are responsible for the antitumoral activity.

[Chemical aspects of steroidal contraceptives]. / Aspect chimique des contraceptifs steroidiques.

PIP: The whole range of current and theoretical contraceptive mechanisms, the mode of action of ovualtion inhibitors in historical perspective, and synthesis of the main groups of contraceptive steroids are reviewed. Male contraceptives that have been explored are steroids which often inhibit libido as well as spermoatogenes is, alkylating agents, antimetabolites, and immunologic methods. Female methods besides inhibition of ovulation include inhibiting ovum transport and endometrial development (IUD), sperm migration (barrier methods), inhibiting fertilization (antihyaluronidases), inhibiting implantation (ergotoxin, hydroxytryptamine, methyl lysergic acid, and antiestrogens). The ovulation inhibitors act by preventing release of gonadotropins. The types of oral contraceptives are continuous progestagens (80-90% effective), and sequentials and combined pills (100% effective). Depot progestagens are being tested. Steroid synthetic schemes are presented for derivatives of estradiol, testosterone, nortestosterone, hydoroxyprogesterone, hydroxypregnadienedione, pregnadiene, and entirely synthetic steroids such as norgestrel and quingestanol.^ieng

Biodegradation potential of some micromycetes for pentachlorophenol.

A first screening was performed upon 100 strains of micromycetes cultivated on solid media (malt extract medium and mineral medium) with pentachlorophenol (PCP) (0.5 g/liter). Under these conditions, 50 strains gave a light blurring around the inoculation spot, indicating some PCP degradation. Later, 50 selected strains were cultivated in liquid synthetic medium with PCP (1 g/liter). After 6 days of cultivation, photodegradation occurred for 25%. On the whole, the consumption of PCP was 25% for Zygomycetes, 3% for yeasts, and 10-15% for Deuteromycetes, except 7% for Tuberculariales. It was shown that glucose repressed the PCP consumption. Among degrading fungi, some could grow with PCP when cultures were initiated with spores, others could not. A more detailed study was done with Phoma glomerata cultivated in liquid synthetic medium (PCP 100 mg/liter) in darkness or with light. Photodegradation increased up to 25% but abiotic degradation occurred also in darkness (8%). Consumption of PCP by Ph. glomerata was 27% after 2 days with light and was lower in darkness (19%).