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Copyright of Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Developing a new chemiluminescence (CL) sensor platform to achieve the identification of pollutants in the water environment is a significant and currently hot topic for researchers. Building on the effective development of a CL internal light source, this paper designed a direct, simple, and rapid pesticide identification strategy. Specifically, graphite carbon nitride quantum dots (CNQDs) with excellent optical properties were synthesized using a solvent heat treatment strategy. Acting as an energy acceptor, CNQDs triggered CL emission in the presence of singlet oxygen (1O 2). The newly developed CNQDs/1O 2 CL sensor exhibited a specific response toward carboxin (CBX) with high sensitivity. Based on this discovery, we have developed a highly selective, ultra-sensitive, and fast CL sensing platform for detecting CBX in water environments. Through numerous experiments, we attributed the CL emission of the CNQDs/1O 2 system to the specific chemiluminescent resonance energy transfer (CRET) process between CNQDs and 1O 2. Interestingly, the CL light of the CNQDs/1O 2 system could serve as an internal light source to excite CBX generating a large amount of 1O 2 through photosensitization, which was crucial for further enhancing the CL efficiency of the CNQDs/1O 2 /CBX system and also enabled the CL sensing of CBX. This study is the first to successfully identify CBX in water using CL sensors, showcasing the potential of CL internal light sources in regulating CL efficiency and offering new perspectives on detecting pollutants in complex environments. [Display omitted] • A CNQDs/1O 2 CL system that leverages the CRET mechanism was engineered. • Internal CL light source sensitized carboxin to boost CNQDs/1O 2 CL emission. • The sensor demonstrated practicality in precisely detecting carboxin in water samples. [ABSTRACT FROM AUTHOR]

Carboxin is a heterocyclic systemic fungicide, mainly used to prevent and control grain smut and wheat rust. Although its mammalian toxicity has been reported, its toxicity to acute exposure to aquatic animals is unknown. In our study, we used zebrafish as aquatic organisms to study Carboxin toxicity. Carboxin can cause developmental toxicity and cardiotoxicity in zebrafish embryos. Histopathological staining of cardiac sections reveals structural changes in zebrafish hearts, and fluorescence quantitative PCR results shows the heart developmental genes mRNA expression levels were disrupted significantly. Besides, carboxin can also cause oxidative stress and reactive oxygen species (ROS) accumulation in zebrafish embryos. The accumulation of ROS causes mitochondrial damage, which is where ATP energy is produced. So ATPase activities and gene expression level were measured and significantly decreased after exposure to carboxin. From the confocal images, the number of blood cells in the heart were decreased significantly after carboxin exposure. Besides, Carboxin exposure can inhibit myocardial cell proliferation. These are all causes to the heart failure, eventually leading to embryos death.

Copyright of Mycosystema is the property of Mycosystema Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, a novel electrochemical biosensor is reported for carboxin detection based on the fabrication of the deoxyribonucleic acid/poly l-methionine-silver nanoparticles/pencil graphite electrode (DNA/PMT-AgNPs/PGE). The electrochemical response of carboxin on the DNA/PMT-AgNPs/PGE was measured using adsorptive differential pulse voltammetry (AdDPV). The electrochemical impedance spectroscopy studies showed lower Rct values for PMT-AgNPs/PGE and DNA/PMT-AgNPs/PGE compared to PGE, demonstrating their good conductivity and faster electron transfer rate. Also, the interaction of DNA with carboxin led to the better accumulation of carboxin on the electrode surface. The proposed biosensor afforded excellent selectivity for carboxin against other pesticides. According to the findings, the DNA/PMT-AgNPs/PGE presents a linear response over the carboxin concentration ranges from 8.0 pM to 1.0 µM. The detection limit was obtained as 5.0 pM under the optimized conditions. The applied DNA/PMT-AgNPs/PGE could successfully detect carboxin in the tap and river water. [ABSTRACT FROM AUTHOR]

Two polymorphic crystal forms of the title compound, C12H13NO2S (systematic name: 6-methyl-N-phenyl-2,3-dihydro-1,4-oxathiine-5-carboxamide), were isolated from a truncated, (12 solvent), polymorph screen on pure lyophillized material. Crystals of form 1 were obtained from all solvents included in the screen with the exception of methanol. As isolated from acetonitrile the crystals are triclinic, space group P\overline{1} with Z′ = 2. Crystals of form 2, which were isolated from methanol only are monoclinic, space group I2/a with Z′ = 1. The crystal packing in both structures is dominated by the formation of infinite –NH...O hydrogen-bonded chains through the carboxamide core.

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aggregation behavior of mixed micellar solutions of cationic hexadecylpiperidinium surfactants and nonionic surfactant Tween 80 is studied. The critical micelle concentration is determined by varying the component ratios, and a negative deviation from the ideal mixing model can be observed (synergistic effect). The adsorption parameters and surface potential of mixed micelles are estimated. The solubilizing effect individual and mixed compositions have on such hydrophobic biologically active compounds as bioflavonoid quercetin and systemic fungicide carboxin is characterized quantitatively via spectrophotometry. [ABSTRACT FROM AUTHOR]

Copyright of Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • A QuEChERS method was modified of carboxin and its metabolites in peanuts. • Supervised field trials were conducted of carboxin in peanuts. • The total carboxin in peanut samples from fields and markets were measured. • The carboxin-exposure risk by eating peanuts was evaluated via a probabilistic model. Abstract We developed an ultra-performance liquid chromatography-tandem mass spectral method to determine the fungicide carboxin and its metabolites, oxycarboxin and carboxin sulfoxide in peanut samples. The method was used to detect the concentration of the analytes in the samples from fields and markets. The total residue quantities in peanut kernels were used to evaluate the chronic dietary risk of total carboxin upon peanut consumption. The estimated dietary intake of carboxin from peanuts whose seeds had been treated with carboxin at the recommended dose was between 0.020% and 0.344% of acceptable daily intake and the risk was found to be negligible. The chronic dietary risk assessment from markets and commercial field samples for various groups of humans indicated that the group with the greatest degree of exposure was 45 to 75-year-old women who lived in rural areas. However, their acceptable daily intake percentage was 0.006%, meaning that their health risk was extremely small. [ABSTRACT FROM AUTHOR]

Two polymorphic crystal forms of the title compound, C12H13NO2S (systematic name: 6-methyl-N-phenyl-2,3-di­hydro-1,4-oxathiine-5-carboxamide), were isolated from a truncated, (12 solvent), polymorph screen on pure lyophillized material. Crystals of form 1 were obtained from all solvents included in the screen with the exception of methanol. As isolated from aceto­nitrile the crystals are triclinic, space group P with Z′ = 2. Crystals of form 2, which were isolated from methanol only are monoclinic, space group I2/a with Z′ = 1. The crystal packing in both structures is dominated by the formation of infinite –NH. . .O hydrogen-bonded chains through the carboxamide core. [ABSTRACT FROM AUTHOR]

Abstract The accurate manipulation of genomic integration of mutant alleles or fluorescent fusion-protein constructs is necessary for understanding of pathogenic mechanism of Magnaporthe oryzae. Recently, this can be achieved by integrating of exogenous DNA randomly into genome of this pathogen, but ectopic integration may result in alteration of gene expression or gene disruption due to unpredictable position effects and/or disruption of protein-coding regions. In this study, we establish a novel strategy for locus-specific integration of exogenous DNA via carboxin-resistance reconstitution by a point-mutation (H245L) on succinate dehydrogenase subunit Mosdi1. Independent transformants derived from the same reconstitution construct showed consistent fluorescent signal and undiversified phenotypes, including hyphae growth, conidiation and pathogenicity, in M. oryzae. Meanwhile, 96 % of all transformants integrate correctly into the Mosdi1 locus as a single copy. Furthermore, we provide a vector carrying yeast recombination cassette and thus allow assembly of multiple overlapping DNA fragments by yeast in vivo recombination for gene complementation and protein localization assay.

Abstract According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the pesticide active substance carboxin. To assess the occurrence of carboxin residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/EEC as well as the European authorisations reported by Member States (including the supporting residues data). Based on the assessment of the available data, MRL proposals were derived and a consumer risk assessment was carried out. Some information required by the regulatory framework was missing and a risk to consumers cannot be excluded for the existing EU MRLs. Hence, the consumer risk assessment is considered indicative only and all MRL proposals derived by EFSA still require further consideration by risk managers and measures for reduction of the consumer exposure should also be considered.

In experiments using Petri dishes in the laboratory and pots in a greenhouse and climate chamber, we examined the influence of seed treatment on emergence of poppy. Four types of fungi (Alternaria spp., Dendryphion penicillatum, Fusarium spp., and Penicillium spp.) were detected on poppy seeds, with the highest infection rate being 72% for D. penicillatum. Surface disinfection decreased infection rate chiefly in D. penicillatum (by 32%) and in Alternaria spp. (by 16%). Seed treatment increased emergence by 9-10% in laboratory experiments but by only 0-6% in greenhouse experiments. Temperature plays an important role in emergence. In climate chamber experiments at a stable temperature of 12°C, the seed treatments increased emergence by 8-16%.

According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the pesticide active substance carboxin. To assess the occurrence of carboxin residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/EEC as well as the European authorisations reported by Member States (including the supporting residues data). Based on the assessment of the available data, MRL proposals were derived and a consumer risk assessment was carried out. Some information required by the regulatory framework was missing and a risk to consumers cannot be excluded for the existing EU MRLs. Hence, the consumer risk assessment is considered indicative only and all MRL proposals derived by EFSA still require further consideration by risk managers and measures for reduction of the consumer exposure should also be considered. [ABSTRACT FROM AUTHOR]

Soil solarization was reported that effective method to control stem rot disease caused by Sclerotium rolfsii, thereby the aim of this study was to improve soil solarization method by combining of biocontrol and chemical control. The experimental was done in the laboratory, pots, greenhouse and micro plot. The effect of high temperatures (45°C, 50°C and 60°C) on the survival of S. rolfsii sclerotia were conducted in the laboratory. At 45 °C, sclerotia treated for 6 hours showed germination of 36%. However, treated at 50°C and 60°C for 1 hours, the sclerotia could not germinate. The effect of soil solarization on sclerotial survival of S. rolfsii was carried under green-house and small plot conditions. The sclerotia were placed deeply under 2 soil levels of 5 and 10 cm and evaluated weekly on germination rate. After 1 week of soil solarization, sclerotia germinated 7.2% at 5 cm depth and 0% after 2 weeks. At 10 cm depth, sclerotia were could not germinate after 1 week of soil solarization. For small plot experiment of soil solarization, the germinated of sclerotia at 5 cm depth was 0% after 3 weeks of soil solarization while 35.2% germination for non solarization. Integrated control of stem rot using fungicide, biocontrol agents and soil solarization was conducted under green-house condition. The result was clearly that soil solarization alone or in combination with others were effective methods against the disease with disease index 0. Without soil solarization, T. harzianium T9 with carboxin caused low disease index of 0.2. The integrated control of stem rot was also undertaken in small plot (1.5×1.5m) experiment with comparison on disease incident and tuber yield of H. tuberrosus. Using soil solarization in combination with T. harzianium T9 and Glomus clarum was the best method that reduced disease with index of 0.33 and provided high tuber yield of 1.69 kg/m2. [ABSTRACT FROM AUTHOR]

Biological N2 fixation is a major factor contributing to the increased competitiveness of Brazilian soybeans on the international market. However, the contribution of this process may be limited by adverse conditions to symbiotic bacteria, such as fungicide seed treatments. This study aimed to evaluate the effects of the fungicides carbendazim + thiram and carboxin + thiram on soybean nodulation, plant growth and grain yield. Two field experiments were carried out in the Cerrado region of the State of Roraima, in a soil with a low organic matter content and no soybean bradyrhizobia. In 2005, seeds were treated with fungicide carbendazim + thiram and commercial inoculants containing the Bradyrhizobium elkanii strains SEMIA 5019 and SEMIA 587 and B. japonicum strains SEMIA 5079 and SEMIA 5080. In 2006, soybean seeds were treated with the fungicides carbendazim + thiram or carboxin + thiram and inoculated separately with each one of the four strains. The plants were evaluated for number of nodules and dry weight, shoot dry weight and total N accumulated in shoots 35 days after plant emergence, while grain yield and N grain content were determined at harvest. Both fungicides reduced soybean nodulation, especially in the presence of B. elkanii strains. The fungicide carbendazim + thiram reduced nodulation by about 50 % and grain yield by more than 20 % (about 700 kg ha-1), in the treatment inoculated with of strain SEMIA 587.A fixação biológica de N2 representa um dos principais fatores que aumentam a competitividade da soja no mercado internacional. Entretanto, a resposta desse processo pode ser limitada por condições adversas à bactéria, como o tratamento de sementes com fungicidas. O objetivo deste estudo foi avaliar o efeito de fungicidas à base de carbendazim + tiram e carboxin + tiram sobre a nodulação, o desenvolvimento das plantas e o rendimento de grãos da cultura da soja. Dois experimentos foram realizados no Cerrado do Estado de Roraima, em solo com baixo teor de matéria orgânica e desprovido de bactérias nodulantes de soja. Em 2005, as sementes de soja foram tratadas com fungicida à base de carbendazim + tiram e inoculação com produtos comerciais contendo as estirpes de Bradyrhizobium elkanii SEMIA 5019 e SEMIA 587 e B. japonicum SEMIA 5079 e SEMIA 5080. Em 2006, as sementes foram tratadas com fungicidas à base de carbendazim+tiram ou carboxin + tiram e inoculação individual com cada uma das quatro estirpes. Aos 35 dias após a emergência das plantas de soja, foram realizadas avaliações da nodulação, matéria seca e N-total da parte aérea e, na colheita, foram avaliados a produtividade e o N total acumulado nos grãos. Ambos os fungicidas reduziram a nodulação das plantas de soja, sobretudo para as estirpes de B. elkanii. O fungicida à base de carbendazim + tiram reduziu significativamente (cerca de 50 %) a nodulação e em mais de 20 % (cerca de 700 kg ha-1), o rendimento de grãos no tratamento inoculado com a estirpe SEMIA 587.

ABSTRACT A Sample of 63 mutants resistant to the fungicide carboxin (Vitavax) was isolated in the parental strains A76 (bwA nicA, brown conidia, nicotinic acid-requiring) and AZG131 (wA lysA azgA131, white conidia, lysine-requiring and resistant to 8-azaguanine) of the ascomycetous fungus Aspergillus amstelodami. All mutants were normal in their morphology and recessive to their respective wild type alleles. Complementation tests in heterokaryons among the mutants put them all in a single gene designated carA (for resistance to carboxin) as the first gene of its kind to be identified in A. amstelodami. Haploidization analysis has shown that carA is not linked in any of the chromosomes I, II, III, IV or VII, but its linkage relation to the other groups (V, VI, VIII or IX) recognized in this fungus was not determined.

For the first time, a nanoformulated fungicide carboxin was obtained to solve the problem of infection of potato tubers with fungi spores. Encapsulation of carboxin in ultra-deformable liposomes protects it from degradation by sunlight, increases solubility in water and penetration through potato skin. Two fluorescent probes, rhodamine B and fluorescein, were used for optimization of original composition and for visualization of the transfersome localization in potato tubers, respectively. Carboxin was encapsulated in lipid formulations with further evaluation of encapsulation efficiency, substrate release rate in vitro , and penetration through the Strat-M® membrane using Franz cells. Using fluorescent microscopy, it was revealed that transfersomes penetrate through the periderm and enter cortex of potato tubers. By the extraction it was shown that potato tubers weighing 100 g included 32 mg of carboxin after the transfersome treatment. The inclusion of carboxin in transfersomes made it possible to increase the maximum concentration of carboxin in water from 0.57 mmol L−1 to 2.8–3.8 mmol L−1, i.e., 5–7 times. [Display omitted] • Ultradeformable liposomes were used for encapsulation of fungicide carboxin. • Obtained system led to increase the water solubility of carboxin by about 5–7 times. • Nanocarriers penetration into potato tubers was shown using fluorescence microscopy. • Transfersomes improved the penetration of carboxin into potato tubers. [ABSTRACT FROM AUTHOR]

The accurate manipulation of genomic integration of mutant alleles or fluorescent fusion-protein constructs is necessary for understanding of pathogenic mechanism of Magnaporthe oryzae. Recently, this can be achieved by integrating of exogenous DNA randomly into genome of this pathogen, but ectopic integration may result in alteration of gene expression or gene disruption due to unpredictable position effects and/or disruption of protein-coding regions. In this study, we establish a novel strategy for locus-specific integration of exogenous DNA via carboxin-resistance reconstitution by a point-mutation (H245L) on succinate dehydrogenase subunit Mosdi1. Independent transformants derived from the same reconstitution construct showed consistent fluorescent signal and undiversified phenotypes, including hyphae growth, conidiation and pathogenicity, in M. oryzae. Meanwhile, 96 % of all transformants integrate correctly into the Mosdi1 locus as a single copy. Furthermore, we provide a vector carrying yeast recombination cassette and thus allow assembly of multiple overlapping DNA fragments by yeast in vivo recombination for gene complementation and protein localization assay. [ABSTRACT FROM AUTHOR]

New procedures for the determination of pesticide carboxin were developed using differential pulse voltammetry, HPLC with amperometric detection and chronopotentiometry at carbon paste electrode and reticulated vitreous carbon electrode, respectively. Developed procedures based on electrochemical oxidation of carboxin were successfully applied on the determination of carboxin in the model samples of drinking and river water. Limits of detection in samples of river water were in 10−7 mol L−1 concentration range for all procedures and electrodes used. All developed procedures proved to be sensitive, accurate and, due to the resistance of the electrode to the passivation, also simple to handle. [ABSTRACT FROM AUTHOR]

Ganoderma multipileum is a medicinal mushroom possessing potent medicinal secondary metabolites. However, in order to improve metabolic activity via molecular breeding, optimized protoplasting, regeneration and genetic transformation systems are mandatory but remain unexplored in G. multipileum. Thus, we sought to fill this gap by testing different parameters for protoplasting, regeneration, and genetic transformation based on the carboxin resistance marker gene. According to our results, the best viable protoplasting conditions were pH 6.0, mycelia age 4 days, enzyme concentration 7.5 mg/mL, 0.6 M sucrose osmoticum and 3 h of enzyme digestion. In a transformation study, a carboxin resistance gene cassette was constructed using PCR mutagenesis and restriction digestion of the native succinate dehydrogenase subunit B gene in G. multipileum. A PCR-restriction fragment length polymorphism strategy was also applied by PCR point mutagenesis to create an AgeI restriction site. The transformation system using carboxin resistant cassette proved amenable. The Sdh gene structure showed an intron structure similar to that of other Basidiomycetes and Ascomycetes. Alignment and analysis of the Sdh gene sequences in numerous fungi revealed conservation at a carboxin resistant point mutation site that could be applied to a wide range of fungal species. Further Sdh gene phylogenetic analysis revealed congruence with species phylogeny but with low bootstrap supporting values. [ABSTRACT FROM AUTHOR]

Abstract We introduced a site-directed mutation in the sdi1 gene and used it as a selective marker for the polyethylene glycol-mediated transformation of Pleurotus eryngii monokaryon protoplasts. The transformants displayed obvious and stable resistance to the fungicide carboxin indicating that the mutant Pesdi1 gene is an efficient selective marker. [ABSTRACT FROM AUTHOR]

First, we attempted to recombine the Shiitake (Lentinula edodes) pyrG (ura3) gene homologously by introducing a donor vector containing a carboxin resistance gene (lecbxR) flanked by homologous sequences of pyrG into protoplasts of the fungus. However, all the carboxin-resistant transformants only contained ectopic insertions of the exogenous gene and no homologous insertions. Agaricomycetes are generally known for their low efficiency of homologous recombination, and a similar result was shown for L. edodes. We then co-introduced a Cas9 plasmid vector containing a CRISPR/Cas9 expression cassette targeting pyrG and donor plasmid vector. As a result, ∆pyrG strains containing the expected homologous recombination were obtained. However, only two of the seven ∆pyrG strains had the Cas9 sequence; the others did not. Our results suggest that genome editing occurred via the transient expression of the CRISPR/Cas9 cassette in the Cas9 plasmid vector introduced into the fungal cell. Transforming pyrG into a ∆pyrG strain (strain I8) resulted in prototrophic strains with an efficiency of 6.5 strains/experiment., (© The Author(s) 2023. Published by Oxford University Press on behalf of FEMS.)

Kluyveromyces marxianus converts whey-borne sugar into ethyl acetate, an environmentally friendly solvent with many applications. K. marxianus DSM 5422 presumably synthesizes ethyl acetate from acetyl-SCoA. Iron limitation as a trigger for this synthesis is explained by a diminished aconitase and succinate dehydrogenase activity (both enzymes depend on iron) causing diversion of acetyl-SCoA from the tricarboxic acid cycle to ester synthesis. Copper limitation as another trigger for ester synthesis in this yeast refers to involvement of the electron transport chain (all ETC complexes depend on iron and complex IV requires copper). This hypothesis was checked by using several ETC inhibitors. Malonate was ineffective but carboxin partially inhibited complex II and initiated ester synthesis. Antimycin A and cyanide as complexes III and IV inhibitors initiated ester synthesis only at moderate levels while higher concentrations disrupted all respiration and caused ethanol formation. A restricted supply of oxygen (the terminal electron acceptor) also initiated some ester synthesis but primarily forced ethanol production. A switch from aerobic to anaerobic conditions nearly stopped ester synthesis and induced ethanol formation. Iron-limited ester formation was compared with anaerobic ethanol production; the ester yield was lower than the ethanol yield but a higher market price, a reduced number of process stages, a faster process, and decreased expenses for product recovery by stripping favor biotechnological ester production. [ABSTRACT FROM AUTHOR]

In experiments using Petri dishes in the laboratory and pots in a greenhouse and climate chamber, we examined the influence of seed treatment on emergence of poppy. Four types of fungi (Alternaria spp., Dendryphion penicillatum, Fusarium spp., and Penicillium spp.) were detected on poppy seeds, with the highest infection rate being 72% for D. penicillatum. Surface disinfection decreased infection rate chiefly in D. penicillatum (by 32%) and in Alternaria spp. (by 16%). Seed treatment increased emergence by 9-10% in laboratory experiments but by only 0-6% in greenhouse experiments. Temperature plays an important role in emergence. In climate chamber experiments at a stable temperature of 12°C, the seed treatments increased emergence by 8-16%. [ABSTRACT FROM AUTHOR]

An outbreak of typhoid fever in rural Malawi triggered an investigation by the Malawi Ministry of Health and the Centers for Disease Control and Prevention in July 2009. During the investigation, villagers were directly consuming washed, donated, pesticide-treated wheat seed meant for planting. The objective of this study was to evaluate the potential for pesticide exposure and health risk in the outbreak community. A sample of unwashed (1430 g) and washed (759 g) wheat seed donated for planting, but which would have been directly consumed, was tested for 365 pesticides. Results were compared with each other (percentage change), the US Environmental Protection Agency's (EPA) health guidance values and estimated daily exposures were compared with their Reference dose (RfD). Unwashed and washed seed samples contained, respectively: carboxin, 244 and 57p.p.m.; pirimiphos methyl, 8.18 and 8.56p.p.m.; total permethrin, 3.62 and 3.27p.p.m.; and carbaryl, 0.057 and 0.025 p.p.m. Percentage change calculations (unwashed to washed) were as follows: carboxin, -76.6%; pirimiphos methyl, + 4.6%; total permethrin, -9.7%; and carbaryl -56.1%. Only carboxin and total permethrin concentration among washed seed samples exceeded US EPA health guidance values (285 x and seven times, respectively). Adult estimated exposure scenarios (1 kg seed) exceeded the RfD for carboxin (8 x ) and pirimiphos methyl (12 x ). Adult villagers weighing 70 kg would have to consume 0.123, 0.082, 1.06, and 280 kg of washed seed daily to exceed the RfD for carboxin, pirimiphos methyl, permethrins, and carbaryl, respectively. Carboxin, pirimiphos methyl, permethrins, and carbaryl were detected in both unwashed and washed samples of seed. Carboxin, total permethrin, and carbaryl concentration were partially reduced by washing. Health risks from chronic exposure to carboxin and pirimiphos methyl in these amounts are unclear. The extent of this practice among food insecure communities receiving relief seeds and resultant health impact needs further study. [ABSTRACT FROM AUTHOR]

The microcrustacean Thamnocephalus platyurus was used to detect the toxicity reduction of carboxin in abiotic degradation compared to biotic degradation. The abiotic degradation was obtained using two sterilized Entisols with different surface properties while the biotic degradation by Pseudomonas aeruginosa was obtained using the fungicide as the only C source. The results showed that the highest toxicity reduction rates for the abiotic degradation were achieved in 20 days with 49.2% for the coarser soil, 60.7% for the soil with a finer texture, whereas for the biotic degradation, 60.6%. Analysis (1H NMR) showed that the soils transformed carboxin to produce sulfoxide and enol in different concentrations depending on the soil properties, while P. aeruginosa metabolized the fungicide to produce inorganic compounds such as ammonium and nitrite, minor degradation pathways were oxidized to sulfoxide and hydrolytic ring-opening to 2-[(2-hydroxyethyl)thio]acetoacetanilide enol. These results indicated that the degradation of carboxin occurred via abiotic catalytic processes as well as via biotic transformation leading to less toxic derivatives and such phenomena are caused by exchange/surface features of soils, rather than by the mere content of clay or organic matter fractions. [ABSTRACT FROM AUTHOR]

Simple, precise, rapid, sensitive and accurate spectrophotometric methods have been developed for the estimation of carboxin in pure form and in its formulations. The first method is based on oxidative coupling of carboxin with 1,10-phenonthrolin in presence of ferric chloride to form orange colored product with λmax of 510 nm.The product obeyed Beer's law in the concentration range 1-10 mL (10 to 100 μg/mL) with molar absorptivity of 1.1425×103 Sandell's sensitivity 0.2061. The second method is based on the reaction of carboxin with 2,2'-bipyridine to form orange red colored product exhibiting λmax of 522 nm with molar absorptivity, Sandell's sensitivity 2.2605×103, 0.1041 respectively. It obeys Beer's law in the concentration range of 0.5-50 mL (5 to 50 μg/mL). The assay of results was found to be in good agreement with label claim. [ABSTRACT FROM AUTHOR]

Abstract: Obligate biotrophic pathogens like the rust fungi are important plant pathogens causing enormous losses on food, forage and biomass crops. The analysis of the molecular details underlying obligate biotrophic host–parasite interactions is mainly hampered by the fact that no system for transformation is available for most obligate biotrophic organisms. Here we report the transient transformation of Uromyces fabae, an obligate biotrophic rust fungus using a biolistic approach. Biolistic bombardment of U. fabae urediospores was used to deliver different color markers (β-glucuronidase (GUS), intron green fluorescent protein (iGFP) and red fluorescent protein (DsRed) and/or a selection marker. Endogenous regulatory elements from U. fabae plasma membrane ATPase (Uf-PMA1) were used to drive expression of the transgenes. In addition to the delivery of color markers, an in planta selection procedure using the fungicide Carboxin was established allowing the propagation of transformants. In addition to mere cytoplasmic expression of the color markers, a nuclear localization signal was fused to DsRed (pRV115-NLS) targeting the fluorescent marker protein to the nuclei. A procedure for the genetic modification of U. fabae was established. The method can be easily adapted for use with other obligate biotrophic fungi. This provides the basis for a more in depth analysis of the molecular principles governing the obligate biotrophic lifestyle. [Copyright &y& Elsevier]

The article presents a study which aims to discuss five carboxin-resistant mutants which showed various responses to carboxin and related fungicides. Mutants from Aspergillus oryza were characterized by the sensitivities of the mycelial growth and succinate dehydrogenase (SDH) activity to carboxin. However, despite a substantial resistance to carboxin showed by mutants, patterns of sensitivity to other fungicides was unique and supplies clues to molecular interaction between SDH and fungicides.

Nonlethal alternatives are needed to manage blackbird (Icterids) damage to rice and sunflower production in the United States. We evaluated 4 registered fungicides on rice seeds (i.e., Allegiance® FL, Thiram 42-S, Trilex®, and Vitavax® 200 preplant seed treatments) and 2 foliar pesticides on sunflower seeds (Cobalt™ insecticide and Flock Buster bird repellent) as candidate blackbird repellents. Red-winged blackbirds (Agelaius phoeniceus) preferred untreated rice relative to rice treated with Thiram (P < 0.001) and Vitavax (P < 0.001), and untreated sunflower relative to sunflower treated with Cobalt (P < 0.001). Blackbirds preferred untreated sunflower relative to sunflower treated with Flock Buster repellent on day 1 of a 4-day preference test (P < 0.001). We observed no difference in consumption of treated versus untreated rice during the Allegiance preference test (P = 0.928), and blackbirds preferred rice treated with Trilex relative to untreated rice (P = 0.003). Although repellency was positively related to tested concentrations of Thiram (P = 0.010), Trilex (P = 0.026), and Vitavax (P < 0.001), maximum repellency was <50% during our concentration-response tests of these seed treatments. Repellency was also positively related to tested concentrations of Cobalt (P < 0.001), and we observed >80% repellency of sunflower treated with Cobalt at ⩾50% of the label rate. We observed no concentration-response relationship for the Allegiance seed treatment (P = 0.341) and Flock Buster repellent (P = 0.952). We recommend implementation of supplemental field studies to compare laboratory efficacy, repellency, and chemical residues of effective avian repellents throughout periods of needed crop protection. [ABSTRACT FROM AUTHOR]

Abstract: Soybean (Glycine max (L.) Merrill) is susceptible to the fungal pathogen, Sclerotium rolfsii from seedling emergence to pod fill. A few systemic and non-systemic fungicides have been recommended as pre-sowing seed treatment (ST) for the management of Sclerotium blight of soybean worldwide. But farmers, especially in developing countries do not utilize ST mainly on account of preoccupation in other practices considered by them essential for sowing. The possibility of ST applied well in advance of sowing was therefore investigated. Results indicated that ST on average increased field emergence by 26.19%, reduced post-emergence mortality (POM) by 49.03% and enhanced seed yield by 23.00%. Seed treatment with carboxin 37.5%+thiram 37.5% @ 0.2% was the best. Seed treatment 50days prior to sowing was superior by increasing emergence, reducing POM and enhancing seed yield with high monetary returns and energy output. [Copyright &y& Elsevier]

The sdhB gene encoding an iron–sulfur (Ip) subunit of succinate dehydrogenase (SDH, EC 1.3.99.1) complex was cloned from Mortierella alpina 1S-4. The deduced amino acid sequence of SdhB from M. alpina 1S-4 showed high similarity to those of SdhB from other organisms. The mutated sdhB ( CBXB) gene encodes a modified SdhB with an amino-acid substitution (a highly conserved histidine residue within the third cysteine-rich cluster of SdhB replaced by a leucine residue) and is known to confer carboxin resistance. We succeeded in transforming M. alpina 1S-4 by using the CBXB gene as a selectable marker gene and expressing the heterologous uidA gene encoding β-glucuronidase of Escherichia coli. Moreover, transformation efficiency was up to 40–50 transformants per 4.0 × 108 spores. This carboxin-transformation system, characterized by marginal background growth and mitotic stability in M. alpina 1S-4, is considered to be widely useful for the wild strain, M. alpina 1S-4, and various derivative mutants without laborious preparation of auxotrophic mutants as a host strain. [ABSTRACT FROM AUTHOR]

In an attempt to get a marker gene suitable for genetical transformation of the ectomycorrhizal fungus Hebeloma cylindrosporum, the gene Hc.SdhR that confers carboxin-resistance was isolated from a UV mutant of this fungus. It encodes a mutant allele of the Fe–S subunit of the succinate dehydrogenase gene that carries a single amino acid substitution known to confer carboxin-resistance. This gene was successfully used as the selective marker to transform, via Agrobacterium tumefaciens, monokaryotic and dikaryotic strains of H. cylindrosporum. We also successfully transformed hygromycin-resistant insertional mutants. Transformation yielded mitotically stable carboxin-resistant mycelia. This procedure produced transformants, the growth of which was not affected by 2 μg l−1 carboxin, whereas wild-type strains were unable to grow in the presence of 0.1 μg l−1 of this fungicide. This makes the carboxin-resistance cassette much more discriminating than the hygromycin-resistance one. PCR amplification and Southern blot hybridisation indicated that more than 90% of the tested carboxin-resistant mycelia contained the Hc.SdhR cassette, usually as a single copy. The AGL-1 strain of A. tumefaciens was a much less efficient donor than LBA 1126; the former yielded ca. 0–30% transformation frequency, depending on fungal strain and resistance cassette used, whereas the latter yielded ca. 60–95%. [ABSTRACT FROM AUTHOR]

Abstract: Mutants exhibiting resistance to the fungicide, carboxin, were isolated from Aspergillus oryzae, and the mutations in the three gene loci, which encode succinate dehydrogenase (SDH) B, C, and D subunits, were identified to be independently responsible for the resistance. A structural model of the SDH revealed the different mechanisms that confer carboxin-resistance in different mutations. The mutant AosdhB gene (AosdhBcxr ) was further examined for possible use as a transformant selection marker. After transformation with AosdhBcxr , carboxin-resistant colonies appeared within 4 days of culture, and all of the examined colonies carried the transgene. Insertion analyses revealed that the AosdhBcxr gene was integrated into AosdhB locus via homologous recombination at high efficiency. Furthermore, AosdhBcxr functioned as a successful selection marker in a transformation experiment in Aspergillus parasiticus, suggesting that this transformation system can be used for Aspergillus species. [Copyright &y& Elsevier]

The objective of this work was to evaluate the effect of carboxin (20% a.i.) + captan (20% a.i.) at a rate of 3 g/kg of seed; carboxin (20% a.i.) + captan (20% a.i.) at a rate of 3 g/kg of seed + thiram (20% a.i.) + tebuconazole (0.6% a.i.) at a rate of 0.228 mL/kg against Fusarium gram inearum and Bipolaris sorokiniana, as well as their potential effects on the physiological quality of seed of two bread wheat (Triticum aestivum) lines. In the germination test on paper towel, the percentage of germination (counts at 4th and 8th days of incubation) was reduced significantly in both hues by the application of the mixture of the four fungicides. In the vigor test, emergence speed of one the two lines was affected equally by both fungicide mixtures, while the dry weight of seedlings did not differ significantly. In the paper blotter test with freezing, both pathogens were equally well controlled by the two fungicide mixtures. In the soil germination test, the percentage of germination was not affected in either line by the application of fungicides, and the incidence of root rot caused by the two pathogens was low compared to the inoculated checks. [ABSTRACT FROM AUTHOR]

Carboxin was synthesized and its heat capacities were measured with an automated adiabatic calorimeter over the temperature range from 79 to 380 K. The melting point, molar enthalpy (ΔfusHm) and entropy (ΔfusSm) of fusion of this compound were determined to be 365.29±0.06 K, 28.193±0.09 kJ mol−1 and 77.180±0.02 J mol−1 K−1, respectively. The purity of the compound was determined to be 99.55 mol% by using the fractional melting technique. The thermodynamic functions relative to the reference temperature (298.15 K) were calculated based on the heat capacity measurements in the temperature range between 80 and 360 K. The thermal stability of the compound was further investigated by differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. The DSC curve indicates that the sample starts to decompose at ca. 290 °C with the peak temperature at 292.7 °C. The TG–DTG results demonstrate the maximum mass loss rate occurs at 293 °C corresponding to the maximum decomposition rate. [Copyright &y& Elsevier]

Succinate:quinone reductase catalyzes electron transfer from succinate to quinone in aerobic respiration. Carboxin is a specific inhibitor of this enzyme from several different organisms. We have isolated mutant strains of the bacterium Paracoccus denitrificans that are resistant to carboxin due to mutations in the succinate:quinone reductase. The mutations identify two amino acid residues, His228 in SdhB and Asp89 in SdhD, that most likely constitute part of a carboxin-binding site. This site is in the same region of the enzyme as the proposed active site for ubiquinone reduction. From the combined mutant data and structural information derived from Escherichia coli and Wolinella succinogenes quinol:fumarate reductase, we suggest that carboxin acts by blocking binding of ubiquinone to the active site. The block would be either by direct exclusion of ubiquinone from the active site or by occlusion of a pore that leads to the active site. [ABSTRACT FROM AUTHOR]