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Harmful cyanobacterial blooms compromise human and environmental health, mainly due to the cyanotoxins they often produce. Microcystins (MCs) are the most commonly measured group of cyanotoxins and are hepatotoxic, neurotoxic, and cytotoxic. Due to MCs ability to covalently bind to proteins, quantification in complex matrices is difficult. To analyze bound and unbound MCs, analytical methods were optimized for analysis in sediment and clam tissues. A clean up step was incorporated to remove lipids, improving percent yield. This method was then applied to sediment and clam samples collected from the Sacramento&ndash, San Joaquin River Delta (Delta) in the spring and fall of 2017. Water samples were also tested for intracellular and extracellular MCs. These analyses were used to quantify the partitioning of MCs among sediment, clams, and water, and to examine whether MCs persist during non-summer months. Toxin analysis revealed that multiple sediment samples collected in the Delta were positive for MCs, with a majority of the positive samples from sites in the San Joaquin River, even while water samples from the same location were below detection limit. These data highlight the importance of analyzing MCs in complex matrices to accurately evaluate environmental risk.

Simple Summary Some insects are beneficial to plants because they eat pest insects and disease-causing fungi; integrating the use of these insects into pest management can help to reduce the need for costly pesticide applications. Twenty-spotted ladybeetles eat plant pathogenic fungi, which helps to reduce disease severity for many economically important crops. In this study, we applied a systemic insecticide to the roots of pumpkin plants and monitored to see if it would be detectable in the spores of a plant pathogenic fungus and whether the insecticide-tainted fungal spores would hurt the ladybeetle larvae. We were able to chemically detect the systemic insecticide in the fungal spores up to 21 days after the plants had been treated with the fungus. We found that the ladybeetles raised on infected plants that had been treated with the systemic insecticide died more rapidly that ladybeetles that had been raised on uninfected or untreated plants. This study is the first to show that systemic insecticides can move from the roots of a plant, into a plant pathogenic fungus, and then have negative effects on a fungus-eating insect. It suggests that growers and land managers need to carefully consider the unintended consequences of insecticide applications. Abstract Applications of systemic pesticides can have unexpected direct and indirect effects on nontarget organisms, producing ecosystem-level impacts. We investigated whether a systemic insecticide (imidacloprid) could be absorbed by a plant pathogenic fungus infecting treated plants and whether the absorbed levels were high enough to have detrimental effects on the survival of a mycophagous beetle. Beetle larvae fed on these fungi were used to assess the survival effects of powdery mildew and imidacloprid in a factorial design. Fungal conidia were collected from treated and untreated plants and were tested for the presence and concentration of imidacloprid. The survival of beetles fed powdery mildew from imidacloprid-treated leaves was significantly lower than that of the beetles from all other treatments. Imidacloprid accumulated in fungal conidia and hyphae was detected at levels considered lethal to other insects, including coccinellid beetles. Water-soluble systemic insecticides may disrupt mycophagous insects as well as other nontarget organisms, with significant implications for biodiversity and ecosystem function.

Freeze-dried rhubarb was fractionated using column chromatography with organic solvents (various ratios of water/methanol and acetone). The seven fractions obtained were examined for antioxidant activity using a gas chromatography/malonaldehyde (GC/MA) assay. Emodin (6-methyl-1,3,8-trihydroxyanthraquinone) in each fraction was analyzed by HPLC with a diode array detector. The amounts of emodin found in the seven fractions ranged from 22.4 ± 0.35 μg/g of dried rhubarb (100% methanol eluate) to 0.33 ± 0.01 μg/g (acetone eluate). Emodin was not detected in the fractions eluted with water/methanol mixtures. Among the seven fractions, the fraction eluted with 100% methanol showed the greatest antioxidant activity and contained the highest level of emodin. This fraction exhibited antioxidant activities by 75.4 ± 13.7% at the level of 50 μg/mL, 92.8 ± 0.6% at the level of 100 μg/mL, and 93.9 ± 1.1% at the level of 500 μg/mL. These levels of antioxidant activity were comparable to those of known antioxidants α-tocopherol and BHT. The strong relationship between amounts of emodin in the fractions and antioxidant activity was observed.

Salvinorin A, which is present in the natural plant Salvia divinorum, is a unique non-nitrogenous compound with hallucinogenic activity. When salvinorin A isolated from leaves of Salvia divinorum was irradiated with 300 nm UV light in ethyl acetate, it degraded from 100 μg/mL to 2.84 ± 0.05 μg/mL in 30 min. The calculated average rate constant k of this degradation was 0.12/min and the half-life was 5.7 min. When authentic salvinorin A was irradiated by UV light in an organic solution or an aqueous solution, it degraded over 90% within 40 min, whereas when it was irradiated by natural sunlight, it took 8 h to degrade 50% both in an organic and an aqueous solution. Three photodegradation products were tentatively identified by gas chromatography/mass spectrometry. Their structures were similar to that of salvinorin A, suggesting that they are also candidate non-nitrogenous hallucinogens.

This study was conducted to evaluate the effect of molinate on retinoids homeostasis in rat testis. Molinate was administrated to male Sprague-Dawley rats (200 mg kg(-1) in corn oil, ip). Retinoid measurements were made at 6, 12, 48 and 168 h time points after administration. Testis levels of retinoic acid decreased (32 %) in a statistically significant manner at the 12 and 48 h time points. However, retinol and retinaldehyde were not significantly affected by molinate. These results suggest that molinate affects retinoic acid synthesis in testis and could contribute to understanding the molecular mechanism of molinate involved testicular toxicity.

The dissipation of spirotetramat (sp) and spirotetramat-enol (sp-enol) was determined in leaves and fruit of grapevine (Vitis vinífera L.) in a commercial vineyard. sp and sp-enol were extracted with acetonitrile:water, and quantification of residues was done on LC-DAD/MS. The LOQ of this method was found 0.002 mg kg-1 , LOD being 0.001 mg kg-1 for both. Recovery rates were in the range of 92 to 103% with coefficients of variation less than 9 and 6%, respectively at three levels (0.02, 0.2 and 0.6 mg kg-1 ). sp degradation in leaves followed first-order kinetics with R2 =0.84 (p < 0.03). In fruit, only 35% of the original concentration of sp was detected at 5 days after application. These results suggest that residual levels of sp and sp-enol in grapes grown under the conditions of this study pose minimal risk to consumers, since residues did not exceed the limit established by the EPA.

Recent studies indicate that trichloroethylene (TCE) may be a male reproductive toxicant. It is metabolized by conjugation with glutathione and cytochrome P450-dependent oxidation. Reactive metabolites produced along both pathways are capable of forming protein adducts and are thought to be involved in TCE-induced liver and kidney damage. Similarly, in situ bioactivation of TCE and subsequent binding of metabolites may be one mechanism by which TCE acts as a reproductive toxicant. Cysteine-conjugate b-lyase (b-lyase) bioactivates the TCE metabolite dichlorovinyl cysteine (DCVC) to a reactive intermediate that is capable of binding cellular macromolecules. In the present study, Western blot analysis indicated that the soluble form of b-lyase, but not the mitochondrial form, was present in the epididymis and efferent ducts. Both forms of b-lyase were detected in the kidney. When rats were dosed with DCVC, no protein adducts were detected in the epididymis or efferent ducts, although adducts were present in the proximal tubule of the kidney. Trichloroethylene can also be metabolized and form protein adducts through a cytochrome P450-mediated pathway. Western blot analysis detected the presence of cytochrome P450 2E1 (CYP2E1) in the efferent ducts. Immunoreactive proteins were localized to efferent duct and corpus epididymis epithelia. Metabolism of TCE was demonstrated in vitro using microsomes prepared from untreated rats. Metabolism was inhibited 77% when efferent duct microsomes were preincubated with an antibody to CYP2E1. Dichloroacetyl adducts were detected in epididymal and efferent duct microsomes exposed in vitro to TCE. Results from the present study indicate that the cytochrome P450-dependent formation of reactive intermediates and the subsequent covalent binding of cellular proteins may be involved in the male reproductive toxicity of TCE. environment, epididymis, male reproductive tract, toxicology

Two multiresidue methods were developed to determine pesticides in air collected in California. Pesticides were trapped using XAD-4 resin and extracted with ethyl acetate. Based on an analytical method from the University of California Davis Trace Analytical Laboratory, pesticides were detected by analyzing the extract by gas chromatography–mass spectrometry (GC-MS) to determine chlorothalonil, chlorthal-dimethyl, cycloate, dicloran, dicofol, EPTC, ethalfluralin, iprodione, mefenoxam, metolachlor, PCNB, permethrin, pronamide, simazine, trifluralin, and vinclozolin. A GC with a flame photometric detector was used to determine chlorpyrifos, chlorpyrifos oxon, diazinon, diazinon oxon, dimethoate, dimethoate oxon, fonophos, fonophos oxon, malathion, malathion oxon, naled, and oxydemeton. Trapping efficiencies ranged from 78 to 92 % for low level (0.5 μg) and 37–104 % for high level (50 and 100 μg) recoveries. Little to no degradation of compounds occurred over 31 days; recoveries ranged from 78 to 113 %. In the California Department of Food and Agriculture (CDFA) method, pesticides were detected by analyzing the extract by GC-MS to determine chlorothalonil, chlorpyrifos, cypermethrin, dichlorvos, dicofol, endosulfan 1, endosulfan sulfate, oxyfluorfen, permethrin, propargite, and trifluralin. A liquid chromatograph coupled to a MS was used to determine azinphos-methyl, chloropyrifos oxon, DEF, diazinon, diazinon oxon, dimethoate, dimethoate oxon, diuron, EPTC, malathion, malathion oxon, metolachlor, molinate, norflurazon, oryzalin, phosmet, propanil, simazine and thiobencarb. Trapping efficiencies for compounds determined by the CDFA method ranged from 10 to 113, 22 to 114, and 56 to 132 % for 10, 5, and 2 μg spikes, respectively. Storage tests yielded 70–170 % recovery for up to 28 days. These multiresidue methods represent flexible, sensitive, accurate, and cost-effective ways to determine residues of various pesticides in ambient air.

One of the most serious diseases in potato cultivars is caused by the pathogen Phytophthora infestans, which affects leaves, stems and tubers. Metalaxyl is a fungicide that protects potato plants from Phytophthora infestans. In Mexico, farmers apply metalaxyl 35 times during the cycle of potato production and the last application is typically 15 days before harvest. There are no records related to the presence of metalaxyl in potato tubers in Mexico. In the present study, we evaluated the effect of Acinetobacter sp on metalaxyl degradation in potato seedlings. The effect of bacteria and metalaxyl on the growth of potato seedlings was also evaluated. A metabolite profile analysis was conducted to determine potential molecular biomarkers produced by potato seedlings in the presence of Acinetobacter sp and metalaxyl. Metalaxyl did not affect the growth of potato seedlings. However, Acinetobacter sp strongly affected the growth of inoculated seedlings, as confirmed by plant length and plant fresh weights which were lower in inoculated potato seedlings (40% and 27%, respectively) compared to the controls. Acinetobacter sp also affected root formation. Inoculated potato seedlings showed a decrease in root formation compared to the controls. LC-MS/MS analysis of metalaxyl residues in potato seedlings suggests that Acinetobacter sp did not degrade metalaxyl. GC-TOF-MS platform was used in metabolic profiling studies. Statistical data analysis and metabolic pathway analysis allowed suggesting the alteration of metabolic pathways by both Acinetobacter sp infection and metalaxyl treatment. Several hundred metabolites were detected, 137 metabolites were identified and 15 metabolic markers were suggested based on statistical change significance found with PLS-DA analysis. These results are important for better understanding the interactions of putative endophytic bacteria and pesticides on plants and their possible effects on plant metabolism.

Recent studies indicate that trichloroethylene (TCE) may be a male reproductive toxicant. It is metabolized by conjugation with glutathione and cytochrome p450-dependent oxidation. Reactive metabolites produced along both pathways are capable of forming protein adducts and are thought to be involved in TCE-induced liver and kidney damage. Similarly, in situ bioactivation of TCE and subsequent binding of metabolites may be one mechanism by which TCE acts as a reproductive toxicant. Cysteine-conjugate beta-lyase (beta-lyase) bioactivates the TCE metabolite dichlorovinyl cysteine (DCVC) to a reactive intermediate that is capable of binding cellular macromolecules. In the present study, Western blot analysis indicated that the soluble form of beta-lyase, but not the mitochondrial form, was present in the epididymis and efferent ducts. Both forms of beta-lyase were detected in the kidney. When rats were dosed with DCVC, no protein adducts were detected in the epididymis or efferent ducts, although adducts were present in the proximal tubule of the kidney. Trichloroethylene can also be metabolized and form protein adducts through a cytochrome p450-mediated pathway. Western blot analysis detected the presence of cytochrome p450 2E1 (CYP2E1) in the efferent ducts. Immunoreactive proteins were localized to efferent duct and corpus epididymis epithelia. Metabolism of TCE was demonstrated in vitro using microsomes prepared from untreated rats. Metabolism was inhibited 77% when efferent duct microsomes were preincubated with an antibody to CYP2E1. Dichloroacetyl adducts were detected in epididymal and efferent duct microsomes exposed in vitro to TCE. Results from the present study indicate that the cytochrome p450-dependent formation of reactive intermediates and the subsequent covalent binding of cellular proteins may be involved in the male reproductive toxicity of TCE.

The fate of residues of seven agrochemicals (chlorfenapyr, quinoxyfen, tebuconazole, fenarimol, pyridaben, and E- and Z-dimethomorph) from the treatment on hops to the brewing of beer was studied. First, a multi-residue analytical method was developed for the determination of pesticide residues in spent hops, trub, wort, and beer. Each matrix was validated over at least two levels of fortification, for all seven compounds, in the ranges 0.05-5.0, 0.001-1.0, 0.001-0.05, and 0.0005-1.0 ppm for spent hops, trub, wort, and beer, respectively. Recoveries ranged from 73 to 136%. Second, the matrixes prepared from hops, which were treated under commercial practices with each compound, were analyzed using the method developed. The use of treated hops resulted in the carryover of 0.001 ppm of tebuconazole, 0.008 Z-dimethomorph, and 0.005 ppm of E-dimethomorph into the wort. The bulk of the remaining residues of all seven compounds was found on the spent hops. Following fermentation, all compounds were found in levels less than 0.0005 ppm in beer, except Z- (0.006 ppm) and E-dimethomorph (0.004 ppm). Third, when all seven pesticides were spiked prior to the pitching of yeast into clean wort, most of the nonpolar compounds (chlorfenapyr, quinoxyfen, and pyridaben) partitioned into the organic material (trub) which settled to the bottom, while the more polar compounds (fenarimol, tebuconazole, and E- and Z-dimethomorph) were generally distributed evenly between the beer and the trub.

An analytical method for the determination of dimethomorph [(E,Z)-4-[3-(4-chlorophenyl)-3-(3,4-dimethoxyphenyl)acryloyl]morpholine] residues in dried hops was developed utilizing liquid−liquid partitioning, automated gel permeation chromatography (GPC), Florisil and aminopropyl solid phase extraction (SPE) column cleanups, and gas chromatography (GC) with mass selective detection (MSD). Method validation recoveries from dried hops ranged from 79 to 103% over four levels of fortification (0.1, 1.0, 5.0, and 20 ppm). Control and dimethomorph-treated hop samples collected from three field sites had residue levels of