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At least 19 recordsLinked to original sources
PubMed1978

Bromacil and diuron residue levels in Florida citrus soils.

The widespread use of herbicides in Florida citrus groves raises the possibility of residue accumulation following repeated applications. To determine residue levels of commonly used herbicides, soil samples were taken from large experimental plots in commercial groves in Polk and Hardee Counties. Bromacil and diuron had been applied in combination at both locations for 7-8 years. Analyses of samples showed low levels of both herbicides at various soil depths to 60 cm. Only a small amount of bromacil was detectable one year after applications, but diuron levels were higher. Continuous applications at recommended rates and frequencies have resulted in maximum bromacil and diuron levels of 3.9 percent and 13.1 percent, respectively, of their total application.

Bromouracil↗
PubMed1979

Genetic localization of diuron- and mucidin-resistant mutants relative to a group of loci of the mitochondrial DNA controlling coenzyme QH2-cytochrome c reductase in Saccharomyces cerevisiae.

Diuron-resistance, DIU (Colson et al., 1977), antimycin-resistance, ANA (Michaelis, 1976; Burger et al., 1976), funiculosin-resistance, FUN (Pratje and Michaelis, 1977; Burger et al., 1977) and mucidin-resistance, MUC (Subik et al., 1977) are each coded by a pair of genetic loci on the mit DNA of S. cerevisiae. In the present paper, these respiratiory-competent, drug-resistant loci are localized relative to respiratory-deficient BOX mutants deficient in coenzyme QH2-cytochrome c reductase (Kotylak and Slonimski, 1976, 1977) using deletion and recombination mapping. Three drug-resistant loci possessing distinct mutated allelic forms are distinguished. DIU1 is allelic or closely linked to ANA2, FUN1 and BOX1; DIU2 is allelic or closely linked to ANA1, MUC1 and BOX4/5; MUC2 is allelic to BOX6. The high recombinant frequencies observed between the three loci (13% on the average for 33 various combinations analyzed) suggest the existence of either three genes coding for three distinct polypeptides or of a single gene coding for a single polypeptide but subdivided into three easily separable segments. The resistance of the respiratory-chain observed in vitro in the drug-resistant mutants and the allelism relationships between respiratory-competent, drug-resistant loci and coQH2-cyt c reductase deficient, BOX, loci strongly suggest that each of the three drug-resistant loci codes for a structural gene-product which is essential for the normal coQH2-cyt c reductase activity and is obviously a good candidate for a gene product of the drug-resistant loci mapped in this paper. Polypeptide length modifications of cytochrome b were observed in mutants deficient in the coQH2-cyt c red and localized at the BOX1, BOX4 and BOX6 genetic loci (Claisse et al., 1977, 1978) which are precisely the loci allelic to drug resistant mutants as shown in the present work. Taken together these two sets of data provide a strong evidence in favor of the idea that there exist three non contiguous segments of the mitochondrial DNA sequence which code for a single polypeptide sequence of cytochrome b. In each segment mutations which modify the polypeptide sequence can occur leading to the loss (BOX mutants) or to a modification (drug resistant mutants) of the enzyme activity.

Antifungal Agents↗
PubMed1977

Induction of hepatic microsomal enzymes by diuron, phenobenzuron, and metabolites in rats.

Microsomal liver enzymes are induced in rats which are fed a diet containing 1000 ppm of phenobenzuron, a phenylurea herbicide, for 7 days: All parameters measured are about 50% higher than control values. This increase is lower after 14 feeding days. Diuron and 3,4-dichloroaniline have a similar, although lower, effect than phenobenzuron. Two other metabolites have no action on microsomal enzymes. The transitory and weak inducing effect of these phenylureas is interesting when compared to other organochlorine pesticides.

Animals↗
PubMed1977

Mitochondrial heredity of resistance to 3-(3,4-dichlorophenyl)-1,1-dimethylurea, an inhibitor of cytochrome b oxidation, in Saccharomyces cerevisiae.

3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), an inhibitor of cytochrome b oxidation, has been used for the selection of three resistant mutants (diur) of Saccharomyces cerevisiae. The mutant diur-64 exhibits in vivo cross-resistance to antimycin A while diur-34 and diur-1 are more sensitive to antimycin A than the parental strain. The three mutants exhibit mitochondrial inheritance according to the following criteria: mitotic segregation of diuron-resistant and diuron-sensitive diploids is obtained among the diploid progeny of a cross between diur and dius; non-Mendelian segregation of diuron resistance (4:0) is observed in spores of tetrads issued from diuron-resistant diploid; extensive ethidium bromide treatment leads to the formation of Q- mutants which no longer transmit diur and dius alleles. Evidence for two distinct diuron-resistant loci were obtained by allelism tests. Recombination analysis shows that diuron-resistance is not located in the polar region of the mitochondrial genome. The diur loci are not linked to the erythromycin locus since the upper limit in recombinants frequency (26%) for a non-polar region is obtained between diur and eryr. A low recombinants frequency (3%) is observed in crosses between diur-34 mutation and the two mutants cob1 and cob2 suggesting that diur-34 might be located between these two cytochrome-b-deficient loci. The resistance to diuron is also expressed in vitro since the oxidation rates of succinate by sonicated submitochondrial particles from the mutants are clearly less sensitive to diuron than that of the wild type.

Antimycin A↗
PubMed1977

Proton translocation and ATP formation coupled to electron transport from H2O to the primary acceptor of photosystem 2.

1. The rate of electron transport from H2O to silicomolybdate in the presence of 3-(3-4-dichlorophenyl)-1,1-dimethylurea (diuron) (which involves the oxygen-evolving enzyme, the photochemistry of photosystem 2 and the primary electron acceptor of photosystem 2) is controlled by internal pH. This is based on the shift of the pH profile of the rate of electron transport upon addition of uncouplers, or by using EDTA-treated chloroplasts. Both stimulation and inhibition of electron transport by addition of uncouplers (depending on external pH) could be observed. These effects are obtained in the diuron-insensitive photoreductions of either silicomolybdate or ferricyanide. These experiments provide strong evidence that a proton translocating site exists in the sequence of the electron transport H2O leads to Q (the primary acceptor of photosystem 2). 2. The photoreduction of silicomolybdate in the presence of diuron causes the formation of delta pH. The value of delta pH depends on the external pH and its maximal value was shown to be 2.4. The calculated internal pH at different external pH values was found to be rather constant, namely between 5.1 -- 5.2. 3. Electron transport from H2O to silicomolybdate (in the presence of diuron) does not support ATP formation. It is suggested that this is due to the fact that the delta pH formed is below the "threshold" delta pH required for the synthesis of ATP. By adding an additional source of energy in the form of a dark diffusion potential created in the presence of K+ and valinomycin, significant amounts of ATP are formed in this system.

Adenosine Triphosphate↗
PubMed1977

Response of soil microbiota to selected herbicide treatments.

Recommended concentrations of paraquat alone and its combination with each of linuron, diuron, atrazine, simazine, and simazine plus diuron exerted little effect on total populations of bacteria, actinomycetes, and fungi in Fox sandy loam under laboratory and simulated field conditions in 66 and 77 days, respectively. Respiration of the total microbiota in soil suspension was afeected by the combinations as well as individual herbicides in various concentrations. Yet, the inhibition of the O2 uptake by any of these herbicides, including some extreme concentrations, was not permanent, indicating adaptation, or suppression of specific organisms. Only linuron in concentrations up to 20 microng/ml stimulated respiration of the soil.

Actinomycetales↗
PubMed1977

[Studies of oxygen uptake (Mehler reactions) in chloroplasts in the presence of silico-molybdic acid].

Silico-molybdic acid (SiMo) alone or in combination with diurone is known to provide for the functioning of various sites of electron transport within photosystem II (PS-II). Using SiMo, the ability of PS-II to competitive reduction of O2 with SiMo in the presence of some activators of O2 uptake (e. g. catalase"ethanol, malonate, oxalate and glyoxalate) was shown. Oxygen uptake (Mehler reaction) with those compounds may be accomplished against the diurone block. The Mehler reactions studied occur in PS-II at the site, uncoupled with phosphorylation, up to the primary acceptor Q, The Mehler reactions with FMN and ferredoxin confirm the fact that PS-II functioning in the presence of SiMo is possible only after its reduction. Photoreduction of NADP is inhibited irrespective of whether the oxidized or reduced form of SiMo is added.

Catalase↗
PubMed1976

[Light-induced redox conversions of cytochrome f in pea leaves].

Redox conversions of cytochrome f were studied in intact pea leaves by double wavelength difference spectrophotometry. Using the inhibition of the photosystem II activity by far red light (719 nm) or diurone, it was found that cytochrome f is located between two photosystems on the oxidative side of photosystem I. The inhibitors of phosphorylation, , e.g. antimycin A and phloridzine, as well as the uncoupler, methylamine, strongly decreased electron transport through the carrier. It is concluded that cytochrome f is functioning in the non-cyclic phosphorylation. It is suggested that in vivo cytochrome f is not coupled with cyclic electron transfer.

Chloroplasts↗