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Результаты 781-790 из 7,240
Use of molecular imprinted polymers as sensitive/selective luminescent sensing probes for pesticides/herbicides in water and food samples
2022
Kumar, Vanish | Kim, Ki Hyun
As non-biological molecules, molecular imprinted polymers (MIPs) can be made as antibody mimics for the development of luminescence sensors for various targets. The combination of MIPs with nanomaterials is further recognized as a useful option to improve the sensitivity of luminescence sensors. In this work, the recent progresses made in the fabrication of fluorescence, phosphorescence, chemiluminescence, and electrochemiluminescence sensors based on such combination have been reviewed with emphasis on the detection of pesticides/herbicides. Accordingly, the materials that are most feasible for the detection of such targets are recommended based on the MIP technologies.
Показать больше [+] Меньше [-]Nitric oxide-mediated alleviation of arsenic stress involving metalloid detoxification and physiological responses in rice (Oryza sativa L.)
2022
Singh, Pradyumna Kumar | Chakrabarty, D. (Debasis) | Dwivedi, Sanjay | Kumar, Amit | Singh, S. P. (Surendra Pratap) | Sinam, Geetgovind | Niranjan, Abhishek | Singh, Poonam C. | Chatterjee, Sandipan | Majumdar, Dipanjali | Tiwari, Manish | Tripathi, Rudra Deo
Rice is a staple crop, and food chain contamination of arsenic in rice grain possesses a serious health risk to billions of population. Arsenic stress negatively affects the rice growth, yield and quality of the grains. Nitric oxide (NO) is a major signaling molecule that may trigger various cellular responses in plants. The protective role of NO during arsenite (AsIII) stress and its relationship with plant physiological and metabolic responses is not explored in detail. Exogenous NO, supplemented through the roots in the form of sodium nitroprusside, has been shown to provide protection vis-à-vis AsIII toxicity. The NO-mediated variation in physiological traits such as stomatal density, size, chlorophyll content and photosynthetic rate maintained the growth of the rice plant during AsIII stress. Besides, NO exposure also enhanced the lignin content in the root, decreased total arsenic content and maintained the activities of antioxidant isoenzymes to reduce the ROS level essential for protecting from AsIII mediated oxidative damage in rice plants. Further, NO supplementation enhanced the GSH/GSSG ratio and PC/As molar ratio by modulating PC content to reduce arsenic toxicity. Further, NO-mediated modulation of the level of GA, IAA, SA, JA, amino acids and phenolic metabolites during AsIII stress appears to play a central role to cope up with AsIII toxicity. The study highlighted the role of NO in AsIII stress tolerance involving modulation of metalloid detoxification and physiological pathways in rice plants.
Показать больше [+] Меньше [-]Associations between prenatal exposure to perfluoroalkyl substances, hypomethylation of MEST imprinted gene and birth outcomes
2022
Ku, Mei-Sheng | Pan, Wen-Chi | Huang, Yen-Tsung | Hsieh, Wu-Shiun | Hsu, Yi-Hsiang | Chen, Pau-Chung | Liu, Zhenyu
Prenatal perfluoroalkyl substance (PFAS) exposure has been linked to adverse birth outcomes, but the underlying mechanism has yet to be elucidated. DNA methylation changes in mesoderm-specific transcript (MEST) imprinted gene may be a mechanism of the prenatal exposure effects of PFASs on fetal growth. The aim was to investigate the prenatal PFASs exposure effects on DNA methylation changes in MEST imprinted gene involved in fetal growth. Among 486 mother-infant pairs from the Taiwan Birth Panel Study, PFASs and DNA methylation levels at 5 CpG sites of MEST promoter region were measured in cord blood. Univariable and multivariable linear regressions were performed to estimate the associations between prenatal PFAS exposure, MEST DNA methylation levels, and child birth outcomes. Mediation analysis was performed to examine the potential pathway of MEST methylation between PFASs and birth outcomes. We found that higher prenatal perfluorooctyl sulfonate (PFOS) exposure was significantly associated with lower methylation levels at 5 CpG sites of MEST promoter region (an adjusted β range: −1.56, −2.22). Significant negative associations were also found between MEST methylation levels and child birth weight. Furthermore, the associations between PFOS and perfluorooctanoic acid (PFOA) exposure and MEST methylation levels were more profound in girls than in boys. The mediated effect of average MEST methylation level between PFOS exposure and birth weight was 18.3 (95% CI = 2.1, 40.2; p = 0.014). The direct effect of PFOS exposure to birth weight independent to average MEST methylation level was −93.2 (95% CI = −170.5, −17.8; p = 0.018). In conclusion, our results suggest that prenatal PFAS exposure, especially PFOS, is associated with lower methylation levels at MEST promoter region, which not only leverages the role of imprinted gene in ensuring the integrity of fetal growth but also provides a potential mechanism for evaluating the prenatal exposure effect.
Показать больше [+] Меньше [-]Varroa mite and deformed wing virus infestations interactively make honey bees (Apis mellifera) more susceptible to insecticides
2022
Zhu, Yu-Cheng | Yao, Jianxiu | Wang, Yanhua
Varroa mite is one of the major adverse factors causing honey bee population decline. In this study, Varroa destructor-infested and uninfested honey bee colonies were established by selective applying miticide (Apivar® amitraz). Mite population was monitored monthly (April–October 2016), and deformed wing virus (DWV) loading was detected seasonally (April, July, and October). Four immunity- and two physiology-related gene expressions, natural mortality, and susceptibility to five insecticides were comparatively and seasonally examined in field-collected honey bee workers. Results showed that Apivar-treated bee colonies had minor or undetectable mite and DWV (using RT-qPCR) infestations in whole bee season, while untreated colonies had substantially higher mite and DWV infestations. In untreated colonies, Varroa mite population irregularly fluctuated over the bee season with higher mite counts in Jun (318 ± 89 mites dropped in 48 h) or August (302) than that (25 ± 4 or 34) in October, and mite population density was not dynamically or closely correlated with the seasonal shift of honey bee natural mortality (regression slope = −0.5212). Unlike mite, DWV titer in untreated colonies progressively increased over the bee season, and it was highly correlated (R² = 1) with the seasonal increase of honey bee natural mortality. Significantly lower gene expressions of dor, PPO, mfe, potentially PPOa and eat as well, in untreated colonies also indicated an association of increased DWV infestation with decreased physiological and immunity-related functions in late-season honey bees. Furthermore, bees with lower mite/DWV infestations exhibited generally consistently lower susceptibilities (contact and oral toxicities) to five representative insecticides than the bees without Apivar treatment. All of these data from this study consistently indicated an interaction of Varroa/viral infestations with insecticide susceptibilities in honey bees, potentially through impairing bee's physiology and immunity, emphasizing the importance of mite control in order to minimize honey bee decline.
Показать больше [+] Меньше [-]Characteristics of oxytetracycline stress-sensitive microbe-dissolved organic matter component interactions during composting
2022
Zhang, Xu | Zhang, Xinlin | Cui, Hongyang | Zhao, Ran | Zhao, Meiyang | Wei, Zimin
Dissolved organic matter (DOM) has important impacts on the transportation of antibiotics through chemical and biological processes in composting. The interaction between DOM and antibiotics is reciprocal. The interaction between DOM ligands and antibiotics could be characterized based on a technique combining parallel factor analysis (PARAFAC) and microbial community structure analysis. However, PARAFAC cannot reveal the dynamic changes in each DOM peak in one PARAFAC component under antibiotic stress. In this study, two-dimensional correlation spectroscopy (2DCOS) combined with PARAFAC and bacterial community diversity analyses were employed to reveal the effects of oxytetracycline (OTC) stress and the key microorganisms on the transformation of different fluorescent peaks from DOM PARAFAC components during chicken manure composting. The results showed that OTC inhibits the transformation between DOM PARAFAC components by inhibiting the core microbial activities involved in the transformation of DOM components. Protein-like components (C1 and C2) were more sensitive to OTC residue, and components with a high humification degree promoted the degradation of OTC. The interaction between special DOM PARAFAC components and certain bacteria affects the degradation of OTC. The DOM PARAFAC components A2(C1), B1(C2), B2(C2) and Z1(C4) enhanced OTC degradation by stimulating the genera Pseudomonas, Glycomyces and Hyphomicrobium. With these promising results, the true effect of DOM PARAFAC components on the degradation of OTC can be revealed, which is helpful for addressing antibiotic contamination to improve the bioavailability of compost products.
Показать больше [+] Меньше [-]Effect of diesel blended with di-n-butyl ether/1-octanol on combustion and emission in a heavy-duty diesel engine
2022
Wang, Jinglan | Sun, Lifang | Luan, Pengpeng | Wu, Yangyi | Cheng, Zhanjun | Zhang, Zhao | Kong, Xiangen | Liu, Haifeng | Chen, Guanyi
Two kinds of C₈ isomers, di-n-butyl ether (DNBE) and 1-octanol, as potential oxygen-containing alternative fuels, show important value in the trade-off between efficiency and emission. In the present work, the effects of DNBE/1-octanol with different proportions (0, 10%, and 20%) blended into diesel on the combustion characteristics, fuel economy, and emission characteristics in a six-cylinder heavy-duty diesel engine were studied at low, medium, and high loads. 1-Octanol with a 20% blending ratio showed different combustion characteristics in the cylinder compared with the other fuels. The economic analysis showed that the brake specific fuel consumption of DNBE–diesel blend fuels was higher than that of 1-octanol–diesel blend fuels, while brake thermal efficiency was the opposite tendency. The emissions of nitrogen oxides (NOx), hydrocarbons (HC), and carbon monoxide (CO) were affected by the types of blend fuels, blending ratios, and loads. In comparison with 1-octanol–diesel blend fuels, the addition of DNBE in diesel promoted the emission of nitrogen oxides, but inhibited the emissions of soot, HC, and CO. DNBE– and 1-octanol–diesel blend fuels increased the weighted brake specific fuel consumption but decreased the weighted brake thermal efficiency compared with diesel in the World Harmonized Stationary Cycle test cycle of Euro VI regulation. The weighted NOx, HC, soot, and CO emissions of blend fuels depended on the types of blend fuels and blend ratios. The weighted NOx, HC, and soot emissions were reduced by blending 1-octanol into diesel, while the weighted CO emission was increased. The weighted CO and soot emissions of diesel blended with DNBE were reduced than that of diesel.
Показать больше [+] Меньше [-]Tracing water-soluble, persistent substances in the Black Sea
2022
Miladinova, S. | Stips, A. | Macias Moy, D. | Garcia-Gorriz, E.
We apply a tracer model linked with a 3D circulation model to simulate transport and fate of water-soluble persistent substances in the Black Sea that do not bioaccumulate to a considerable extent. The model uses specified degradation time and identical concentrations in the rivers to build a correlation between average concentration in the basin and half-life (DT50). The average concentration in certain sub-regions of the Black Sea can be estimated using an exponential dependence of DT50, if DT50 and concentration in rivers are known. Averaging is performed on the simulations from 2000 to 2019 with real atmospheric forcing and river runoff. A well-defined seasonal cycle is evident for the average shelf concentration, while the average concentration in the deep region does not show a pronounced seasonal cycle or inter-annual variations. With the help of the existing observational data, we estimate DT50 and concentration in the rivers for carbamazepine, sulfamethoxazole and terbuthylazine. Atrazine and simazine are believed to have accumulated in the basin for a long time due to their widespread use in the past and the slow rate of degradation in the marine environment.
Показать больше [+] Меньше [-]Short-term effects of cold spells on plasma viscosity: Results from the KORA cohort study in Augsburg, Germany
2022
Ni, Wenli | Schneider, Alexandra | Wolf, Kathrin | Zhang, Siqi | Chen, Kai | Koenig, Wolfgang | Peters, Annette | Breitner, Susanne
As the underlying mechanisms of the adverse effects of cold spells on cardiac events are not well understood, we explored the effects of cold spells on plasma viscosity, a blood parameter linked to cardiovascular disease. This cross-sectional study involved 3622 participants from the KORA S1 Study (1984–1985), performed in Augsburg, Germany. Exposure data was obtained from the Bavarian State Office for the Environment. Cold spells were defined as two or more consecutive days with daily mean temperatures below the 3ʳᵈ, 5ᵗʰ, or 10ᵗʰ percentile of the distribution. The effects of cold spells on plasma viscosity were explored by generalized additive models with distributed lag nonlinear models (DLNM). We estimated cumulative effects at lags 0–1, 0–6, 0–13, 0–20, and 0–27 days separately. Cold spells (mean temperature <3ʳᵈ, <5ᵗʰ or <10ᵗʰ percentile) were significantly associated with an increase in plasma viscosity with a lag of 0–1 days [%change of geometric mean (95% confidence interval): 1.35 (0.06–2.68), 1.35 (0.06–2.68), and 2.49 (0.34–4.69), respectively], and a lag of 0–27 days [18.81 (8.97–29.54), 17.85 (8.29–28.25), and 7.41 (3.35–11.0), respectively]. For the analysis with mean temperature <3ʳᵈ or 10ᵗʰ percentile, we also observed significant associations at lag 0–20 days [8.34 (0.43–16.88), and 4.96 (1.68, 8.35), respectively]. We found that cold spells had significant immediate and longer lagged effects on plasma viscosity. This finding supports the complex interplay of multiple mechanisms of cold on adverse cardiac events and enriches the knowledge about how cold exposure acts on the human body.
Показать больше [+] Меньше [-]Impact of microorganisms and entomopathogenic nematodes used for plant protection on solitary and social bee pollinators: Host range, specificity, pathogenicity, toxicity, and effects of experimental parameters
2022
Erler, Silvio | Eckert, Jakob H. | Steinert, Michael | Alkassab, Abdulrahim T.
Pollinating bees are stressed by highly variable environmental conditions, malnutrition, parasites and pathogens, but may also by getting in contact with microorganisms or entomopathogenic nematodes that are used to control plant pests and diseases. While foraging for water, food, or nest material social as well as solitary bees have direct contact or even consume the plant protection product with its active substance (e.g., viruses, bacteria, fungi, etc.). Here, we summarize the results of cage, microcolony, observation hive assays, semi-field and field studies using full-size queen-right colonies. By now, some species and subspecies of the Western and Eastern honey bee (Apis mellifera, A. cerana), few species of bumble bees, very few stingless bee species and only a single species of leafcutter bees have been studied as non-target host organisms. Survival and reproduction are the major criteria that have been evaluated. Especially sublethal effects on the bees' physiology, immune response and metabolisms will be targets of future investigations. By studying infectivity and pathogenic mechanisms, individual strains of the microorganism and impact on different bee species are future challenges, especially under field conditions. Overall, it became evident that honey bees, bumble bees and few stingless bee species may not be suitable surrogate species to make general conclusions for biological mechanisms of bee-microorganism interactions of other social bee species. Solitary bees have been studied on leafcutter bees (Megachile rotundata) only, which shows that this huge group of bees (∼20,000 species worldwide) is right at the beginning to get an insight into the interaction of wild pollinators and microbial plant protection organisms.
Показать больше [+] Меньше [-]Characterisation of plasmatic B-esterases in bottlenose dolphins (Tursiops truncatus) and their potential as biomarkers of xenobiotic chemical exposures
2022
Solé, M. | Figueres, E. | Mañanós, E. | Rojo-Solís, C. | García-Párraga, D.
A total of 164 blood samples from 16 clinically healthy bottlenose dolphins (Tursiops truncatus), were obtained from an aquarium in Spain between 2019 and 2020, as part of their preventive medicine protocol. In addition to conventional haematological and biochemical analyses, plasmatic B-esterase activities were characterised to determine the potential application of such analyses in wild counterparts. The hydrolysis rates for the substrates of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and carboxylesterase (CE) activity in plasma were measured, the last using two commercial substrates, p-nitrophenyl acetate (pNPA) and p-nitrophenyl butyrate (pNPB). Activity rates (mean ± SEM in nmol/min/mL plasma) were (in descending order): AChE (125.6 ± 3.8), pNPB-CE (65.0 ± 2.2), pNPA-CE (49.7 ± 1.1) and BuChE (12.8 ± 1.3). These values for dolphins are reported in here for the first time in this species. Additionally, the in vitro sensitivity of two B-esterases (AChE and pNPB-CE) to chemicals of environmental concern was determined, and the protective role of plasmatic albumin assessed. Out of the B-esterases measured in plasma of dolphin, AChE activity was more responsive in vitro to pesticides, while CEs had a low response to plastic additives, likely due to the protective presence of albumin. However, the clear in vitro interaction of these environmental chemicals with purified AChE from electric eels and recombinant human hCEs (hCE1 and hCE2) and albumin, predicts their impact in other tissues that require in vivo validation. A relationship between esterase-like activities and health parameters in terrestrial mammals has already been established. Thus, B-esterase measures could be easily included in marine mammal health assessment protocols for dolphins as well, once the relationship between these measures and the animal's fitness has been established.
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