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At least 19 recordsLinked to original sources
PubMed1998

Correlation of Lipid Peroxidation in Botrytis cinerea Caused by Dicarboximide Fungicides with Their Fungicidal Activity.

Dicarboximide fungicides iprodione, vinclozolin, and procymidone were examined for their capacity to inhibit mycelial growth, to cause cellular leakage, and to cause lipid peroxidation on Botrytis cinerea isolate BC2. All three fungicides effectively inhibited the mycelial growth of the fungi. The IC(50) values were found to be about 2 µM for all three fungicides, indicating that the fungicidal activity of the individual fungicides was almost the same. The fungicides caused significant cellular leakage and lipid peroxidation on the fungi in a concentration-dependent manner. Fungicidal activity of the three individual fungicides on inhibiting mycelial growth of the fungi correlated positively well with both cellular leakage and lipid peroxidation that were caused by the respective fungicides. Positive correlations were also found between the degree of cellular leakage and lipid peroxidation following treatment with the fungicides. Our results support the view that dicarboximide fungicides exert their fungicidal activity mainly through membrane lipid peroxidation and subsequent cellular leakage from the treated fungi.

Journal Article↗
PubMed1991

Kinetics and requirements for activation of macrophages for fungicidal activity: effect of protein synthesis inhibitors and immunosuppressants on activation and fungicidal mechanism.

Peritoneal-and pulmonary macrophages can be activated in vitro with lymphokines (LK) or IFN-gamma, without exogenous lipopolysaccharide, for fungicidal activity against several pathogenic fungi. However, neither the biochemical nor metabolic events of the activation process or of the effector phase have been defined. In the present work we sought to elucidate these events with time-course studies using inhibitors of protein synthesis as well as immunosuppressive agents. We found that protein synthesis inhibitors abrogated the activation process, because cycloheximide (CHX) (1-2 micrograms/ml) prevented activation of macrophages for fungicidal activity against Candida albicans, Blastomyces dermatitidis, and Paracoccidioides brasiliensis. Blocking of the activation process by CHX was not due to macrophage cytotoxicity, and CHX did not impair the ability of nonactivated macrophages to kill Candida parapsilosis. In kinetic studies we showed that activation of macrophages was induced in 4 hr of LK treatment and that CHX had no effect if added after this time. In contrast to CHX, therapeutic concentrations of hydrocortisone (HC), such as less than or equal to 5 micrograms/ml, or cyclosporin A (CsA), 5 micrograms/ml, did not significantly inhibit LK activation of macrophages for killing of fungi. In the effector phase, the fungicidal capacity of activated macrophages in short-term (less than or equal to 4 hr) killing assays could not be abrogated by CHX (5 micrograms/ml), HC (100 micrograms/ml), or CsA (10 micrograms/ml). These results demonstrate that the activation but not the effector mechanism of macrophages for fungicidal activity is blocked by inhibition of protein synthesis. In contrast, therapeutic concentrations of HC or CsA may not interfere with activation of macrophages or their killing mechanisms, thus providing a rationale for antifungal immunotherapy in certain clinical situations (e.g., infection in the immunosuppressed patient).

Animals↗
PubMed1994

Fungicides and photochemistry: photodegradation of the azole fungicide penconazole.

In order to examine the photostability of the fungicide penconazole (1-(2,4-dichloro-beta-propylphenethyl)-1H-1,2,4-triazole, 1) in the field, model experiments with organic solvents were performed. Photodegradation (lambda > 280 nm) of penconazole was found to be more efficient in isopropanol and cyclohexane solution than in the presence of cyclohexene. Photolysis in isopropanol and cyclohexane resulted in considerable formation of 1-(4-chloro-beta-propylphenethyl)-1H-1,2,4-triazole (2) and 5H,6H-(1,2,4-triazolo)-[5,1-a]-9-chloro-6-propyl-isoquinoline (3). Furthermore, photodehalogenation of 3 yielded traces of 5H,6H-(1,2,4-triazolo)-[5,1-a]-6-propyl-isoquinoline (4) and, in the presence of isopropanol 5H,6H-(1,2,4-triazolo)-[5,1-a]-9-(2-hydroxy-2-methylethyl)-6-propyl- isoquioline (5). Additionally, a lot of polar products were found in high yields which could not be isolated and characterized individually. In the presence of cyclohexene, on the other hand, photodecomposition and photodehalogenation to photoproduct 2 were found to be the main degradation pathways and photoproduct 3 was only detected as a trace component.

Chromatography, High Pressure Liquid↗
PubMed1996

Occupational allergic contact dermatitis and airborne contact dermatitis from 5 fungicides in a vineyard worker. Cross-reactions between fungicides of the dithiocarbamate group?

We report a patient with occupational contact dermatitis due to sensitization to mancozeb and perhaps metiram used in a vineyard. Patch testing showed strong allergic patch test reactions to 2 of the commercially available preparations used (Dithane Ultra and Polyram WG). Further patch tests showed allergic patch test reactions to mancozeb (0.5 and 1% pet.), a weak reaction to metiram (1% pet.) as well as to 4 other fungicides of the dithiocarbamate group (maneb, nabam, propineb and zineb), which had never been used in the vineyard.

Adult↗
PubMed1994

Analysis of dithiocarbamate fungicides. Reaction products of the thiuram disulphide fungicide thiram (TMTD) during acid hydrolysis.

The acid hydrolysis products (CS2, COS, and H2S) of thiram (tetramethylthiram disulphide, TMTD) absorbed in a methanolic amine reagent (ethylenediamine, piperidine) were investigated by second derivative UV spectroscopy. When the hydrolysis temperatures are below the boiling point the formation of the side products COS and H2S at the expense of CS2 is unavoidable. Failure to carefully scrub the liberated gases with a lead acetate solution leads to the absorption of H2S also in the amine reagent and, like COS, causes an absorption at 230 nm that is erroneously attributed to COS. With the second-derivative technique it has been undoubtedly proved that, under the conditions of the Deutsche Forschungsgemeinschaft method S 15, thiram liberates CS2 and COS in a molar ratio of 1.92 to 0.06 (average of eight determinations) but not in a molar ratio of 1.5 to 0.5, as previously reported by some workers. Under these conditions it is impossible, contrary to earlier claims, to differentiate thiram from other dithiocarbamates based on the ratio of the hydrolysis products in residue analysis.

Hydrogen-Ion Concentration↗
PubMed2004

Synthesis and fungicidal activity of enantiomerically pure (R)- and (S)-silicon-containing azole fungicides.

Enantiomerically pure (R)- and (S)-1-(1H-1,2,4-triazol-1-yl)-2-(4-fluorophenyl)-3-trimethylsilylpropan-2-ol 1 were prepared via an enantioselective Grignard reaction. The absolute stereochemistry of 1 was determined by X-ray analysis. In a comparison of in vitro antifungal activities of the enantiomers, the (-)-enantiomer with the R-absolute configuration was far more potent than the (+)-enantiomer.

Antifungal Agents↗
PubMed2001

The ABC transporter BcatrB from Botrytis cinerea is a determinant of the activity of the phenylpyrrole fungicide fludioxonil.

This study demonstrates that the ATP-binding cassette (ABC) transporter BcatrB from Botrytis cinerea influences the activity of phenlpyrrole fungicides against the pathogen. This conclusion is based on toxicity assays and northern analysis experiments which show that BcatrB replacement mutants, which do not express the BcatrB gene, show an increased sensitivity to the phenylpyrrole fungicides fludioxonil and fenpiclonil. Mutants overexpressing BcatrB exhibit a decreased sensitivity to these fungicides. In addition, accumulation of fludioxonil by BcatrB replacement mutants was higher than by wild-type isolates. For mutants overexpressing BcatrB the reverse was observed. Additional ABC and major facilitator superfamily (MFS) transporter genes were identified in an expressed sequence tag (EST) database, suggesting that B cinerea has gene families of ABC and MFS transporters. Corresponding fragments of ten ABC (BcatrC-BcatrN) and three MFS transporter genes (Bcmfs1-4) were cloned and characterised. Fludioxonil affected the transcript level of some members of these gene families in germlings during a short treatment with the fungicide at sub-lethal concentrations. Hence, other ABC and MFS transporters may affect the activity of phenylpyrrole fungicides as well. Other fungicides such as the anilinopyrimidine fungicide cyprodinil, the azole fungicide tebuconazole, the dicarboximide fungicide iprodione and the strobilurin fungicide trifloxystrobin also induced transcription of some of the ABC and MFS transporter genes identified. Therefore, we propose that various ABC and MFS transporters function in protection of the fungus against fungicides and are involved in multi-drug resistance development.

ATP-Binding Cassette Transporters↗
PubMed2003

Effects of fludioxonil and pyrimethanil, two fungicides used against Botrytis cinerea, on carbohydrate physiology in Vitis vinifera L.

In Vitis vinifera L, photosynthesis and photosynthate partitioning are affected in the presence of fludioxonil and pyrimethanil, two fungicides commonly used in vineyards against Botrytis cinerea Pers. However, the effects were found to be different according to the model studied: plantlets (cv Chardonnay) grown in vitro, fruiting cuttings (cv Chardonnay) and plants grown in vineyards (cvs Chardonnay, Pinot noir and Pinot Meunier). In the plantlets grown in vitro, both fungicides decreased gas exchanges, photosynthetic pigment and starch concentrations in the leaves, whereas soluble carbohydrates transiently accumulated, suggesting that plantlets mobilised starch in response to photosynthesis inhibition caused by fungicides. In the fruiting cuttings, the fungicides did not affect photosynthesis, although fludioxonil caused starch decrease in parallel with sucrose accumulation, suggesting that the fungicide effects were of lower intensity than in vitro. Conversely, in vineyard, the two fungicides stimulated photosynthesis and increased pigment concentrations in the three vine cultivars tested. In the meantime, glucose, fructose and starch levels of the leaves declined after fungicide exposure, whereas sucrose accumulated, indicating that sucrose synthesis increased in the leaves following the fungicide treatment. Among the three varieties, Chardonnay was the most sensitive to the fungicides as revealed by the intensity of the responses and the longer period for recovery. In vineyard, the results suggested that the two fungicides, in addition to inhibiting B cinerea development, had a beneficial effect on vine physiology through the stimulation of leaf carbon nutrition, which may further enable the plant to rapidly make use of its defence reactions.

Botrytis↗
PubMed2004

Seed treatment and its implication for fungicide exposure assessment.

Farmers may be exposed to fungicides through both personal application and use of treated seed. Most epidemiology studies rely on personal application to assess exposure. We explored the extent of potential exposure via use of treated seed using data from a large cohort of licensed pesticide applicators from Iowa and North Carolina. Potential secondary fungicide exposure due to treated seed was calculated by crop by multiplying the average percent of seed treated by those reporting raising that crop but not applying fungicide. This potential exposure was present for every crop with treated seed (corn, soybean, wheat, cotton, potato, and peanut), and was highest for corn (71%) and soybean farmers (19%). Potential secondary fungicide exposure was more common in Iowa than in North Carolina since most Iowa farmers plant corn and soybeans and few report applying fungicides. Owing to its widespread use on corn, potential secondary captan exposure may occur among the 90% of the individuals planting corn. The relative intensity of secondary fungicide exposure associated with planting treated seed is anticipated to be lower than actively applying fungicide. Limited data suggest that exposure during planting may be approximately 4% of actively applying fungicide; while seed transfer operations may have similar levels of exposure to personal application (80-200%). Measurement data are necessary to characterize the patterns of exposure related to the use of fungicide-treated seed and to determine whether this route of exposure is an important contributor to fungicide exposure among farmers.

Agriculture↗
PubMed2004

Transformation of copper oxychloride fungicide into copper oxalate by tolerant fungi and the effect of nitrogen source on tolerance.

Aspergillus niger and Penicillium chrysogenum were able to grow on Czapek Dox medium amended with elevated concentrations [up to 500 ppm active ingredient (ai)] of the fungicide copper oxychloride. Solubilization of the fungicide in solid medium was evident by the appearance of a clear (halo) zone underneath and around the growing colonies. The halo formed with A. niger, grown on fungicide-containing nitrate nitrogen medium, was found subsequently to enclose concentric rings of newly crystalline precipitate. These crystals were extracted, examined by scanning electron microscopy and IR, and identified as copper oxalate. The supplemented nitrogen source to the medium greatly affected both fungicide solubilization and fungal tolerance. Ratios of fungicide solubilization rate (R(S)) in relation to the colony growth rate (R(G)) were significantly higher on ammonium than on nitrate nitrogen medium for both fungal strains. Growth ratios (the colony extension rate in the presence of a given concentration of the fungicide in relation to the control colony growth rate) of A. niger were markedly lower on ammonium than on nitrate nitrogen medium. The cellular copper contents, taken up from the fungicide, and the medium titratable acidity were higher in ammonium than in nitrate medium for both fungi. These results suggested fungal possession of variable tolerance mechanisms to this fungicide by complexation and/or precipitation of copper in the medium. Additionally, this work emphasizes the activity of fungi in transformation of insoluble inorganic metal-containing fungicides into insoluble organic metal compounds, which has a potentiality in metal cycling in biogeochemical and environmental context.

Biodegradation, Environmental↗
PubMed1989

Comparative acute renal effects of three N-(3,5-dichlorophenyl)carboximide fungicides: N-(3,5-dichlorophenyl)succinimide, vinclozolin and iprodione.

A large number of carboximides have been synthesized, tested and, in some cases, marketed as agricultural fungicidal agents. One carboximide fungicide N-(3,5-dichlorophenyl)succinimide (NDPS) proved to be both highly efficacious as a fungicide and a nephrotoxin. The purpose of this study was to compare the acute nephrotoxic potential of three N-(3,5-dichlorophenyl)carboximide fungicides [NDPS, vinclozolin (VCLZ) and iprodione (IPDO)] to determine if nephrotoxic potential correlated with fungicidal efficacy among this class of structurally-related agricultural agents. Male Fischer 344 rats (4 rats/group) received a single intraperitoneal injection of a fungicide (0.4 or 1.0 mmol/kg) or vehicle (sesame oil, 2.5 ml/kg), and renal function was monitored at 24 and 48 h. NDPS (0.4 or 1.0 mmol/kg)-induced renal effects were characterized by marked diuresis, increased proteinuria, elevated blood urea nitrogen (BUN) concentration and kidney weights, decreased organic ion accumulation by renal cortical slices and proximal tubular necrosis. In contrast, IPDO and VCLZ (0.4 or 1.0 mmol/kg) administration resulted in only minor or no alterations in the renal function parameters studied and renal morphology. These results suggest that fungicidal efficacy does not correlate with acute nephrotoxic potential among the N-(3,5-dichlorophenyl)carboximide fungicides.

Aminoimidazole Carboxamide↗