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Effects of fenoxycarb on growth and reproduction of Daphnia magna were examined under realisitic exposure conditions as defined by predictions form laboratory fate studies and observations in the field. Initial concentrations were...
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Effects of fenoxycarb on growth and reproduction of Daphnia magna were examined under realisitic exposure conditions as defined by predictions form laboratory fate studies and observations in the field. Initial concentrations were administered in a single pulse dose and altered to mimic the reduction of fenoxycarb that occurs following field application to natural waters (half- life ≌10 hour). Potential effects on the developmentalstage of test organisms were determined by exposure of four age groups: less than 24 h, 4 to 6d, 8 d, and 11 d.
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This study assessed the effects of exposure to IGRs on the long-term development of the honeybee colony, viability of queens and sperm production in drones and integrated the data into a honeybee population model. Colonies treated...
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This study assessed the effects of exposure to IGRs on the long-term development of the honeybee colony, viability of queens and sperm production in drones and integrated the data into a honeybee population model. Colonies treated with diflubenzuron resulted in a short-term reduction in the numbers of adult bees and brood. Colonies treated with fenoxycarb declined during the season earlier and started the season slower. The number of queens that successfully mated and laid eggs was affected in the fenoxycarb treatment group but there were no significant differences in the drone sperm counts between the colonies. An existing honeybee population model was modified to include exposure to IGRs. In the model, fenoxycarb reduced the winter size of the colony, with the greatest effects following a June or an August application. Assuming a 'larvae per nurse bee' ratio of 1.5 for brood rearing capability, the reduction in winter size of a colony following a fenoxycarb application was at its worst about 8%. However, even if only those bees reared within 2 weeks of the IGR being applied are subject to premature ageing, this might significantly reduce the size of over-wintering colonies, and increase the chance of the bee population dwindling and dying in late winter or early spring.
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Rapid biomolecular observation in model indicator organisms has been considered as a potential predictor of water pollution from chronic and trace toxicants. This study evaluated the use of Daphnia magna metabolomic measurements a...
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Rapid biomolecular observation in model indicator organisms has been considered as a potential predictor of water pollution from chronic and trace toxicants. This study evaluated the use of Daphnia magna metabolomic measurements as indicators for exposure to reproductive endocrine disruptors by using the model juvenile hormone analogue fenoxycarb. Because D. magna reproduction controls metabolic regulation, the reproduction stage was also carefully considered in metabolic observations and data analysis to examine differences. Comparisons of metabolite abundance regulation between 1 and 12 days of fenoxycarb exposure were performed to investigate the predictability of the sub-chronic (12 days) adverse impacts on reproduction and metabolic regulation based on acute (1 day) metabolic observations. ANOVA-simultaneous component analysis (ASCA) detected reversed patterns in direction of timecourse metabolite abundance regulation with fenoxycarb exposure. For example, decreases in the abundances of leucine, asparagine, methionine, and isoleucine which then changed to increases were observed with time during fenoxycarb exposures. The reversed regulation pattern was observed at the last reproduction stage (stage 3), exclusively. Pearson correlation analysis showed that correlations of pairwise metabolites were disrupted with fenoxycarb exposure. Similar to ASCA, data normalization based on the reproduction stage improved the detectability of significant correlations. The disruption on ambient metabolite regulation patterns and pairwise metabolite correlations was consistently observed with both 1 and 12 days of fenoxycarb exposures for sets of select metabolites. The observed regulatory disruptions to these specific metabolites suggest altered oogenesis as the affected metabolites and the specific reproduction stage are related to successful oogenesis. This study demonstrates that D. magna metabolic dysregulation is a predictor of water contamination by endocrine disrupting compounds. The high predictability of sub-chronic (12 days) endocrine disruption was confirmed based on acute (1 day) metabolic observations. Furthermore, integration of the reproduction cycle information in D. magna metabolomics was validated by observing a reproduction stage specific dysregulation in metabolite abundance regulation, which was not observable from the broader data analysis. Consequently, this study confirms the potential for establishing a quantitative relationship between water quality and indicator species metabolic observations. Additionally, it was found that constraining variables relevant to toxicity mechanisms of interest, such as the reproduction stage, is a key consideration for extraction of ecologically meaningful information in environmental metabolomics. (c) 2020 Elsevier Ltd. All rights reserved.
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Two samples of silver doped into zeolite Y were prepared and characterized. ICP and SEM-EDS analysis indicate that the AgY1 sample contains twice the amount of silver compared to the AgY2 sample. Solid state luminescence spectrosc...
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Two samples of silver doped into zeolite Y were prepared and characterized. ICP and SEM-EDS analysis indicate that the AgY1 sample contains twice the amount of silver compared to the AgY2 sample. Solid state luminescence spectroscopy shows variations in the emission modes of the site-selective luminescence where various luminophores might be excited upon selecting the proper excitation energy. The selected material effectively decomposed the pesticide fenoxycarb in aqueous solution. The photodecomposition of fenoxycarb reached 80 % upon irradiation for 60 min in the presence of the AgY1 catalyst. 2-(4-Phenoxy-phenoxy)ethyl] carbamic acid (1) and 1-amine-2-(phenoxy-4-ol) ethane (2) were identified as products for both uncatalyzed solution and the catalyzed fenoxycarb with AgY2 catalyst. Whereas, compound (2) was the only product identified in the catalyzed reaction with AgY1.
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In this research work, the susceptibility of egg and four larval instars of Leptinotarsa decemlineata (Say) (Col.: Chrysomelidae) to Insect Growth Regulators (IGRs) compounds (lufenuron 25% EC and fenoxycarb 25% WP) was determined...
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In this research work, the susceptibility of egg and four larval instars of Leptinotarsa decemlineata (Say) (Col.: Chrysomelidae) to Insect Growth Regulators (IGRs) compounds (lufenuron 25% EC and fenoxycarb 25% WP) was determined. Different larval instar groups were separated by measuring the head capsule width and were used in all bioassays. The data were analysed with log-probit transformation using the SPSS software. The LC50 for egg was determined by dipping egg masses in different concentration of either compound for 10 s, and LC50 values for each group of larvae was estimated by using treated potato plants. The LC50 values of lufenuron on egg, first, second and third instars of larvae were 682.65, 40.58, 47.83 and 261.38 ppm, respectively, and for fenoxycarb, these were estimated as 897.50, 35.60, 57.91 and 355.23 ppm, respectively. The LD50 values of lufenuron and fenoxycarb on second instar larvae were 139.56 and 228.42 ppm, respectively.
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Fenoxycarb was applied @ 0.5,1.0,2.0,5.0 and 10.0 fig/moth topically on freshly emerged unmated adults of Spot/opter?litura to study its effect on the reproductive potential of the insect. When treated moths were allowed to mate w...
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Fenoxycarb was applied @ 0.5,1.0,2.0,5.0 and 10.0 fig/moth topically on freshly emerged unmated adults of Spot/opter?litura to study its effect on the reproductive potential of the insect. When treated moths were allowed to mate with treated and untreated counterparts, the fecundity, egg viability, oviposition period and longevity of mated and unmated adults of both sexes decreased with the increase in doses. Detrimental effects were greater in the crosses of both treated sexes.
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Fenoxycarb was applied @ 0.5,1.0,2.0,5.0 and 10.0 fig/moth topically on freshly emerged unmated adults of Spot/opter?litura to study its effect on the reproductive potential of the insect. When treated moths were allowed to mate w...
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Fenoxycarb was applied @ 0.5,1.0,2.0,5.0 and 10.0 fig/moth topically on freshly emerged unmated adults of Spot/opter?litura to study its effect on the reproductive potential of the insect. When treated moths were allowed to mate with treated and untreated counterparts, the fecundity, egg viability, oviposition period and longevity of mated and unmated adults of both sexes decreased with the increase in doses. Detrimental effects were greater in the crosses of both treated sexes.
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In holometabolous insects, many tissues and organs such as the fat body and midgut undergo a remodeling process during metamorphosis. Larval fat body cells are eliminated by programmed cell death (PCD), while tissue cells that ada...
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In holometabolous insects, many tissues and organs such as the fat body and midgut undergo a remodeling process during metamorphosis. Larval fat body cells are eliminated by programmed cell death (PCD), while tissue cells that adapt to adult life are formed by stem cells. In this study, we analyzed the features of the remodeling period of Galleria mellonella fat body in terms of PCD types, apoptotic and autophagic cell death characteristics. Besides, the effects of juvenile hormone (JH) on these processes were evaluated under the modified hormonal conditions via applications of JH analog, fenoxycarb. Several hallmarks of apoptotic and autophagic cell death were analyzed by morphological, biochemical, and molecular methods. The results of the present study have ascertained that the degeneration process of larval cells occurs via autophagic cell death accompanied by caspase-3 activity during the pupal period and it is regulated by 20-hydroxyecdysone (20HE) mediated by ecdysone receptor B1 (EcR-B1). Increased activity of the acid phosphatase and upregulation of ATG6 and ATG8 in parallel with the formation of autophagosomes in the fat body of Galleria during the pupal period strongly indicated that autophagy was the key player in the remodeling processes.
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? 2022 Elsevier LtdThe aims of this study were to: i) analyze the prevalence and concentration of pesticides belonging to 4 major classes, namely organochlorines, organophosphates, carbamates and pyrethroids in chicken meat, liver...
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? 2022 Elsevier LtdThe aims of this study were to: i) analyze the prevalence and concentration of pesticides belonging to 4 major classes, namely organochlorines, organophosphates, carbamates and pyrethroids in chicken meat, liver and kidney; ii) evaluate the impact of boiling, frying and freezing on pesticide levels in chicken meat, and iii) estimate the dietary exposure to pesticide residues in chicken meat and conduct a risk assessment. Liquid chromatography-mass spectrophotometry (LC – MS/MS) was used to determine the concentrations of pesticide residues in samples. A total of 300 domestic (local) and imported samples were collected from the marketplace in Jordan. About 2.3%, 48.3%, 83%, and 46.3% of the samples exceeded MRLs for the organochlorine, organophosphorus, carbamate and pyrethroid pesticide groups, respectively. About 90% of the local and imported muscle samples and almost all the local and imported liver samples contained one or more pesticide above the MRL. Among all the samples tested, two pesticides, namely deltamethrin and fenoxycarb, occurred in high concentrations. Domestic samples were observed to have higher concentrations of pesticides compared to their imported counterparts. The pesticides concentrations decreased by about 50, 75 and 15% after boiling, frying and freezing, respectively. Risk assessment has shown that there is no potential risk from consuming chicken meat, however, local chicken meat is of more concern than is imported product. This study will help food control authorities develop appropriate regulations regarding the use of pesticides in Jordan.
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BACKGROUNDThe objective was to refine the standard regulatory exposure scenario used in plant protection product authorisations by developing a more realistic landscape-related GIS-based exposure assessment for terrestrial non-tar...
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BACKGROUNDThe objective was to refine the standard regulatory exposure scenario used in plant protection product authorisations by developing a more realistic landscape-related GIS-based exposure assessment for terrestrial non-target arthropods. We quantified the proportion of adjacent off-target area in agricultural landscapes potentially exposed to insecticide drift from applications of the active substance fenoxycarb. High-resolution imagery, landscape classification and subsequent stepwise analysis of a whole landscape using drift and interception functions were applied to selected areas in representative fruit-producing regions in Germany.
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