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At least 217 records · Page 12Linked to original sources
PubMed2005

Effects of two fungicides with multiple modes of action on reproductive endocrine function in the fathead minnow (Pimephales promelas).

Many chemicals that adversely affect reproduction and/or development do so through multiple pathways within the reproductive tract and hypothalamic-pituitary-gonadal axis. Notable in this regard are fungicides, such as prochloraz or fenarimol, which in mammals have the potential to impact endocrine function through inhibition of CYP enzymes involved in steroid metabolism, as well as through antagonism of the androgen receptor(s). The objective of our studies was to assess the effects of prochloraz and fenarimol on reproductive endocrine function in a model small fish species, the fathead minnow (Pimephales promelas), using both in vitro and in vivo assays. The two fungicides inhibited in vitro CYP19 aromatase activity in brain and ovarian homogenates from the fish, with prochloraz exhibiting a greater potency than fenarimol. Prochloraz and fenarimol also bound competitively to the cloned fathead minnow androgen receptor expressed in COS-1 cells. The two fungicides significantly reduced fecundity of the fish in a 21-day reproduction assay at water concentrations of 0.1 (prochloraz) and 1.0 (fenarimol) mg/l. The in vivo effects of prochloraz on plasma steroid (17beta-estradiol, testosterone, 11-ketotestosterone) and vitellogenin (an estrogen-responsive protein) concentrations, as well as on gonadal histopathology, were consistent with inhibition of steroidogenesis. Fenarimol also affected several aspects of endocrine function in vivo; however, the suite of observed effects did not reflect either aromatase inhibition or androgen receptor antagonism. These studies contribute to a better mechanistic understanding of the extrapolation of effects of endocrine-disrupting chemicals across vertebrate classes.

Animals↗
PubMed1981

Induction of fenarimol-efflux activity in Aspergillus nidulans by fungicides inhibiting sterol biosynthesis.

Fungicides inhibiting sterol biosynthesis belong to chemically distinct classes such as imidazole, morpholine, pyridine, pyrimidine and triazole derivatives. Incubation of mycelium of Aspergillus nidulans for 90 min with representatives of these fungicides induced an efflux activity which prevented accumulation of fenarimol, a pyrimidine derivative, into the mycelium. Induction of this efflux activity reduced the fungitoxicity of fenarimol. Addition of oligomycin to mycelium in which fenarimol-efflux activity was induced immediately increased the uptake of fenarimol, indicating that the efflux activity is energy-dependent. Subsequent disruption of membrane permeability with sodium lauryl sulphate instantaneously caused leakage of fenarimol from the mycelium into the medium. The ability to induce fenarimol efflux is rather specific for inhibitors of sterol biosynthesis: except for pimaricin, fungicides with unrelated mechanisms of action did not have this ability.

Aspergillus nidulans↗
PubMed1992

In vitro evaluation of acaricidal and fungicidal activity of the house dust mite acaricide, Allerbiocid.

The acaricidal and fungicidal activities of a new acaricide Allerbiocid, formulated for the control of house dust mites, were investigated. The components of the Allerbiocid formula are: 3% benzyl benzoate (acaricidal and fungicidal), 1% tannic acid (protein denaturant) and 0.5% Tween (surface active agent) in 70% isopropyl alcohol (antiseptic). At application rates of both 150 and 250 ml/m2, the acaricidal activity appeared to work by both ingestion and contact and remained active upon contact with mites for up to 10 weeks. When Sabouraud agar was treated with Allerbiocid at a concentration of 5 ml/20 ml medium, the preparation was also found to have fungicidal and fungistatic activities on various species of fungi commonly found in house dust. Allerbiocid contains tannic acid which is a protein denaturant. Levels of Der p I in dust were found to be reduced by over 90% after treatment with Allerbiocid. The importance of denaturation of mite faecal allergens and allergens associated with dead fungal spores is discussed.

1-Propanol↗
PubMed1987

The action of the systemic fungicides tridemorph and fenpropimorph on sterol biosynthesis by the soil amoeba Acanthamoeba polyphaga.

Tridemorph and fenpropimorph, two systemic fungicides known by their inhibitory effects on sterol biosynthesis in fungi and plants, were administered in vivo to the amoeba Acanthamoeba polyphaga. The compounds did not kill the cells, but modified completely their sterol pattern. Fungicide-exposed cells accumulated cyclopropylsterols indicating a partial blockage of the cyclopropane isomerase as in higher plants and delta 8-sterols indicating an inhibition of the delta 8----delta 7 isomerase as in fungi. Three new sterols, 4 alpha-methylergosta-9(11),24(28)-dienol, ergosta-6,8,22-trienol and poriferasta-6,8,22-trienol were isolated and identified, the former from control cells, the two latter from fungicide-treated cells. These results are in accordance with our previous results on the presence of cycloartenol as sterol precursor and confirm our hypothesis on a phylogenetic relationship of Acanthamoeba polyphaga with photosynthetic phyla.

Amoeba↗
PubMed2001

Cloning of the CYP51 gene from the eyespot pathogen Tapesia yallundae indicates that resistance to the DMI fungicide prochloraz is not related to sequence changes in the gene encoding the target site enzyme.

Resistance to sterol 14 alpha-demethylase inhibitor (DMI) fungicides has been correlated with mutations in the CYP51 gene encoding the target enzyme eburicol 14 alpha-demethylase. CYP51 was isolated from the eyespot pathogen Tapesia yallundae revealing a predicted 526-amino acid product exhibiting homology to other fungal CYP51s. CYP51 was sequenced from four field isolates sensitive or resistant to the DMI fungicide prochloraz and partially sequenced from two further isolates and eight progeny from a cross between prochloraz-sensitive and -resistant parents. Two alleles of the gene were detected termed CYP51-1 and CYP51-2. No correlation was found between sequence change and fungicide sensitivity. Therefore prochloraz resistance involved a mechanism other than mutation in the target site gene.

Amino Acid Sequence↗
PubMed1975

Control of ovine lupinosis: experiments on the use of fungicides.

Experiments were conducted in 4 successive years to assess whether certain fungicides when applied to lupins would control the disease, ovine lupinosis. Results were variable, ranging from failure of fungicidal sprays to prevent the disease in 1969/70 to partial success in 1970/71. Fumigation with methyl bromide was very effective. It is concluded that none of the fungicides tried could be considered as a practical means of controlling the disease.

Animals↗
PubMed2003

Occupational asthma from fungicides fluazinam and chlorothalonil.

We report two cases of occupational asthma caused by sensitisation to powdered fungicides fluazinam and chlorothalonil, from the same fungicide formulation plant. Both developed work related lower respiratory symptoms after a latent interval of asymptomatic exposure. The diagnosis in each case was confirmed with a serial peak flow record in the workplace followed by specific inhalation tests. These fungicides are known to cause dermatitis; this report indicates that these compounds can induce specific immunological reactions in the airways as well as skin.

Aminopyridines↗
PubMedDate not supplied

Degradation of N,N'-dibutylurea (DBU) in soils treated with only DBU and DBU-fortified benlate fungicides.

N,N'-dibutylurea (DBU) is a breakdown product of benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], the active ingredient in Benlate fungicides, and has been proposed to cause crop damage after the use of Benlate 50 DF fungicide (DuPont, Wilmington, DE). Our research focused on DBU persistence after application into soil. We assessed DBU persistence on direct application of DBU (carbonyl-(14)C) at two concentrations (0.08 and 0.8 microg DBU kg(-1)) to seven soils and two potting mixes in soil microcosms incubated at various combinations of soil water potential (-0.03 or -0.1 MPa) and temperature (23, 33, 44 degrees C). For two soils at a subset of treatment variables we assessed DBU persistence in the presence of Benlate DF and SP fungicide formulations. Parent compounds, metabolites, and (14)CO(2) were tracked using chromatographic analysis with radioassay and UV detection, liquid scintillation counting, and post-extraction oxidation of the soil. DBU degradation was primarily microbial and for most soil-treatment combinations, half-lives were less than 2 wk. DBU degradation was retarded at the lower soil water potential and enhanced at 33 degrees C. In the presence of the formulation, DBU degradation was slower for one soil type. The longest half-life observed in any case was less than 7 wk; therefore, long-term persistence of DBU applied to soils through a Benlate application is very unlikely.

Chromatography↗
PubMed2004

Changes in soil chemical properties and microbial activities in response to the fungicide Ridomil Gold plus copper.

The purpose of the study was to investigate changes of soil chemical and biological properties changes resulting from a single application of the fungicide Ridomil Gold plus copper (Ridomil Gold plus)(mefenoxam 6% + copper oxide 60%) at the following rates 0.25, 0.5, 1, 2, and 10 g m(-2). Selected chemical properties generally differed between fungicide rates over longer incubation periods. Microbial activity indices (available N, ammonification rates and specific enzymatic systems) were more sensitive indicators of change. Values of these indicators generally increased with incubation period and decreased or increased at high rates. Significant changes in P availability occurred after 90 days of incubation at rates > or = 1 g m(-2). Incorporation of the fungicide significantly increased NH4+ levels in soil after 75 days of incubation. These changes stimulated soil microbial activity as evidenced by increased ammonification rates especially at long-term exposure. Of the enzyme activities studied, dehydrogenase and beta-glucosidase activities were the most sensitive to ridomil gold plus. This sensitivity was more pronounced with the dehydrogenase activity.

Acid Phosphatase↗
PubMedDate not supplied

[The effect of biostimulants and fungicides on the growth parameters of natural associations of soil microorganisms].

Biostimulants ivin and emistym take positive effect on the growth characteristics of natural association of soil microorganisms: they increase the specific growth rate, the number of generations, decrease the lag-phase and duration of redoubling the number of microorganisms. Presence of fungicides in the medium inhibits the growth of microorganisms. Under combined use of biostimulants and fungicides one cannot reveal the negative effect of fungicides on the natural associations of microorganisms, however the stimulating action of growth-regulating substances decreases.

Culture Media↗
PubMed2000

Effect of the fungicide benomyl on spore germination and hyphal length of the arbuscular mycorrhizal fungus Glomus mosseae.

The fungicide benomyl inhibited spore germination and hyphal length of the arbuscular mycorrhizal fungus Glomus mosseae when applied at doses of 21.25 microg/ml (agronomic dose), 10.62 microg/ml and 10 microg/ml. G. mosseae was able to germinate in the presence of 2.12 microg/ml of benomyl, and the percentage of spore germination was unaffected by dosis of 0.1, 0.01 and 0.001 microg/ml of the fungicide. However, all doses of fungicide tested in this study decreased the hyphal length. When ungerminated G. mosseae spores previously exposed to benomyl were transferred to water-agar medium without benomyl, the maximum germination was 16%. Small spores of G. mosseae were more resistant to benomyl than the larger ones. Our results show some of the factors which can explain the variability of the effect of benomyl on arbuscular mycorrhizal fungi.

Benomyl↗
PubMed2004

Comparative effect of the fungicide Prochloraz-Mn on Agaricus bisporus vegetative-mycelium and fruit-body cell walls.

Fungicides to control mycopathogens of commercial Agaricus bisporus, a mushroom cultivated for human consumption, are a major field of study, since these chemicals are toxic to both the host and its fungal parasites. The fungicide Prochloraz-Mn, used at its LD50 for A. bisporus, partially inhibited protein biosynthesis in the vegetative mycelial cell walls of this mushroom and caused significant changes in cell-wall polysaccharide structure, as deduced by methylation analysis and gas liquid chromatography-mass spectrometry (GLC-MS). Furthermore, the aggregated mycelial walls showed distinct alterations in their overall chemical composition following the administration of Prochloraz-Mn at the LD50 and the LD50 x1000. As expected, GLC-MS studies indicated that the latter dose caused more appreciable differences in polysaccharide structure. The decrease in mushroom crop yields obtained from industrial cultures treated with Prochloraz-Mn to control V. fungicola infection depended on the dose of the fungicide employed, whereas fruit-body morphology was only slightly affected at the highest Prochloraz-Mn concentration used.

Agaricus↗
PubMed2004

Fungicide effect on nitrogenase activity in methylotrophic bacteria.

The study comprised tests on the effect of fungicides: Oxafun T, Funaben T and Baytan Universal on the nitrogenase activity of methylotrophic bacteria, selected from the rhizosphere and non-rhizosphere soil of spring barley. The obtained results indicated that the field dose of fungicides - 0.5 ppm had no effect on all the examined strains of methylotrophic bacteria. The dose of 50 ppm, however, had varied effects, suppressing or stimulating, depending on the particular strain. The highest concentration of fungicides applied, i.e. 100 ppm in all cases suppressed the nitrogenase activity of the strains under examination.

Bacteria↗
PubMedDate not supplied

Determination of 22 triazole compounds including parent fungicides and metabolites in apples, peaches, flour, and water by liquid chromatography/tandem mass spectrometry.

A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed for the determination of 14 parent triazole fungicides and 8 of their metabolites found in apples, peaches, flour, raw water, and tap water. The triazole fungicides chosen for this multiresidue method development project included propiconazole, fenbuconazole and its RH-9129 and RH-9130 metabolites, cyproconazole, difenoconazole, tebuconazole and its HWG 2061 metabolite, hexaconazole, bromuconazole (both stereoisomers), epoxiconazole, tetraconazole, triticonazole and its RPA-404886 and RPA-406341 metabolites, triadimefon, triadimenol, and myclobutanil. Of special concern to the U.S. Environmental Protection Agency were the metabolites common to all triazole fungicides: free triazole, 1,2,4-triazole (T), and its 2 conjugates: triazolylalanine (TA) and triazolylacetic acid (TAA). These metabolites were the primary focus of this project. All samples we cleaned up by a combination of C18 solid-phase extraction (SPE), mixed-mode cationic SPE, and mixed-mode anionic SPE columns. A triple-stage quadrupole mass spectrometer, equipped with electrospray ionization in the positive-ion mode, was used to determine the compounds of interest. T, TA, and TAA were quantitated using isotopically labeled internal standards (IS), in which the 1,2,4-triazole ring had been synthesized by using 13C and 15N (IS_T, IS_TA, and IS_TAA). These isotopically labeled internal standards were necessary to correct for matrix effects. The T, TA, and TAA metabolites were quantitated at the 25-50 parts-per-billion (ppb) level in food commodities and at 0.50 ppb in water. Recoveries were 70-101% from apples, 60-121% from peaches, 57-118% from flour, 75-99% from raw water, and 79-99% from tap water.

Calibration↗
PubMed2005

A new post-harvest fungicide to control fruit rot on apple and pear.

PHILABUSTER is a new post-harvest fungicide developed by Janssen Pharmaceutica N.V.. It provides an advanced mould control by post-harvest treatments of citrus and pome fruit. The product is formulated as a stable suspension concentrate intended for dilution in water before use. PHILABUSTER 400 SC contains 200 g/L imazalil and 200 g/L pyrimethanil. Both active ingredients have a different single site mode of action. Imazalil inhibits ergosterol biosynthesis (DMI), whereas pyrimethanil interferes with fungal enzyme secretion and methionine biosynthesis. Due to the combination of these low risk fungicides a good anti-resistance management can be obtained. In case of existing reduced sensitivity of a population to DMI or MBC fungicides, no cross-resistance with pyrimethanil was observed. PHILABUSTER showed good activity by post-harvest treatment against key pathogens on apple and pear Penicillium expansum (blue mold), Botrytis cinerea (gray mold) and Gloeosporium spp. (lenticel rot) in small and large scale experiments with artificial or natural infections. By dip treatment of large volumes of fruit (up to 50 tons) the depletion of both active ingredients in the treatment water was low, both when plastic or wooden bins were used. Lower dose rates resulted in an inferior and inconsistent residue level of both active ingredients on fruit. Possible advantages of post-harvest treatments versus field treatments for the control of storage diseases are discussed.

Botrytis↗
PubMed1982

Field screening method for above-tolerance residues of dithiocarbamate fungicides.

A field screening method has been developed for detecting above-tolerance residues of dithiocarbamate (DTC) fungicides on fruits and vegetables. A harvested crop might be condemned as unfit for market if above-tolerance DTC residues are present; however, by using this screening method, a grower might be able to postpone harvesting a crop until the screening test indicates that residues have dissipated below the tolerance level. The method depends on carbon disulfide generated from DTC fungicides at an elevated temperature into the headspace gas above the contents of a septum-sealed reaction flask, with hydrochloric acid and stannous chloride present. The syringe-withdrawn, headspace carbon disulfide then reacts with the appropriate chromophore reagent already in the syringe. The lower limit of detectability is about 2 ppm DTC fungicide from 30 g chopped crop. A single test can be completed in about 90 min; the average time per test when several are conducted sequentially is considerably shorter.

Fruit↗
PubMed1996

[Fungicidal activity of imbricin and its salts].

The fungicidal activity of imbricin and its salts against fungal phytopathogens was studied. The biological tests revealed that the compounds had a fungicidal activity and inhibited the development of a number of plant diseases. Imbricin showed a marked fungicidal activity when used as a disinfectant of wheat seeds and in the control of root rot of cucumbers. It was demonstrated that imbricin and its salts had the growth regulating activity in plant cell culture.

Ascomycota↗
PubMed2005

Insecticidal and fungicidal activity of new synthesized chitosan derivatives.

Chitosan, the N-deacetylated derivative of chitin, is a potential biopolysaccharide owing to its specific structure and properties. In this paper, we report on the synthesis of 24 new chitosan derivatives, N-alkyl chitosans (NAC) and N-benzyl chitosans (NBC), that are soluble in dilute aqueous acetic acid. The different derivatives were synthesized by reductive amination and analyzed by 1H NMR spectroscopy. A high degree of substitution (DS) was obtained with N-(butyl)chitosan (DS 0.36) at a 1:1 mole ratio for NAC derivatives and N-(2,4-dichlorobenzyl)chitosan (DS 0.52) for NBC derivatives. Their insecticidal and fungicidal activities were tested against larvae of the cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), the grey mould Botrytis cinerea Pers (Leotiales: Sclerotiniaceae) and the rice leaf blast Pyricularia grisea Cavara (Teleomorph: Magnaporthe grisea (Hebert) Barr). The oral feeding bioassay indicated that all the derivatives had significant insecticidal activity at 5 g kg(-1) in artificial diet. The most active was N-(2-chloro-6-fluorobenzyl)chitosan, which caused 100% mortality at 0.625 g kg(-1), with an estimated LC50 of 0.32 g kg(-1). Treated larvae ceased feeding after 2-3 days; the mechanism of action remains unknown. In a radial hyphal growth bioassay with both plant pathogens, all derivatives showed a higher fungicidal action than chitosan. N-Dodecylchitosan, N-(p-isopropylbenzyl)chitosan and N-(2,6-dichlorobenzyl)chitosan were the most active against B cinerea, with EC50 values of 0.57, 0.57 and 0.52 g litre(-1), respectively. Against P grisea, N-(m-nitrobenzyl)chitosan was the most active, with 77% inhibition at 5 g litre(-1). The effect of different substitutions is discussed in relation to insecticidal and fungicidal activity.

Animals↗