Academic literature on the topic 'Pesticidal activities'
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Journal articles on the topic "Pesticidal activities"
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Ali, M. M., M. Jesmin, S. M. A. Salam, J. A. Khanam, M. F. Islam, and M. N. Islam. "Pesticidal Activities of Some Schiff Bases Derived from Benzoin, Salicylaldehyde, Aminophenol and 2,4 Dinitrophenyl Hydrazine." Journal of Scientific Research 1, no. 3 (August 29, 2009): 641–46. http://dx.doi.org/10.3329/jsr.v1i3.2585.
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The pesticidal activities of three Schiff bases namely PDH [N- (1 phenyl 2 hydroxy 2 phenyl ethylidine) 2¢4¢ dinitrophenyl hydrazine], PHP [N(1-phenyl 2 hydroxy -2 phenyl ethylidine) 2¢ hydroxy phenyl imine] and HHP [N (2-hydroxy benzylidine) 2¢ hydroxy phenyl imine] derived from benzoin, salicylaldehyde, 2 aminophenol and 2,4 dinitrophenyl hydrazine were evaluated against Tribolium castaneum. Probit mortality were studied by surface film treatment method at different doses of the compounds. The results showed that the LD50 values as recorded after 24 hours of treatment were 15.1268, 3.0922 and 3.0922 mg /cm2 for PDH, PHP and HHP, respectively as compared with 0.2416 mg/cm2 for a standard pesticide l-cyhalothrin. With Schiff base complexes of cobalt(II), copper(II) and zinc(II), the LD50 values were 1.5206, 14.8576 and 3.2829 mg/cm2 respectively. Better results were obtained when recorded with longer treatment time. These three compounds may, therefore, be considered as potent pesticides. Keywords: Pesticidal activities; Schiff bases; Surface film treatment method. © 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245(Online). All rights reserved. DOI: 10.3329/jsr.v1i3.2585 J. Sci. Res. 1 (3), 641-646 (2009)
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Park, Eun Sil, In Kyung Bae, Hwang Ju Jeon, and Sung-Eun Lee. "Limonoid derivatives and its pesticidal activities." Entomological Research 44, no. 4 (July 2014): 158–62. http://dx.doi.org/10.1111/1748-5967.12059.
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Badawy, Mohamed E. I., Anter Kenawy, and Ahmed F. El-Aswad. "Toxicity Assessment of Buprofezin, Lufenuron, and Triflumuron to the EarthwormAporrectodea caliginosa." International Journal of Zoology 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/174523.
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Earthworms are particularly important soil macroinvertebrates and are often used in assessing the general impact of pesticide pollution in soil. The present study was conducted in order to investigate the toxicity of three insect growth regulators (IGRs) buprofezin, lufenuron, and triflumuron, at different application rates and exposure times toward mature earthwormsAporrectodea caliginosa. The effects of these pesticides on the growth rate in relation to the activities of acetylcholinesterase (AChE) and glutathione S-transferase (GST) as biochemical indicators were evaluated to elucidate the mechanisms of action. Toxicity studies indicated that lufenuron was the most harmful pesticide to mature earthworms, followed in descending order by buprofezin and triflumuron. A reduction in growth rate in all pesticide-treated worms was dose-dependent over the 28-day exposure period, which was accompanied by a decrease in AChE and GST activities. Relationships between growth rate, AChE, and GST provided strong evidence for the involvement of pesticidal contamination in the biochemical changes in earthworms, which can be used as a bioindicator of soil contamination by pesticides.
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Liu, Xing-Hai, Wei Yu, Li-Jing Min, David E. Wedge, Cheng-Xia Tan, Jian-Quan Weng, Hong-Ke Wu, et al. "Synthesis and Pesticidal Activities of New Quinoxalines." Journal of Agricultural and Food Chemistry 68, no. 28 (June 12, 2020): 7324–32. http://dx.doi.org/10.1021/acs.jafc.0c01042.
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KOYANAGI, Tohru, Hiroshi OKADA, Osamu IMAI, Tadaaki TOKI, and Takahiro HAGA. "Synthesis and Pesticidal Activities of N-Phosphinoyl Heterocycles." Journal of Pesticide Science 22, no. 3 (1997): 187–92. http://dx.doi.org/10.1584/jpestics.22.187.
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Xu, Jianwei, Min Lv, Shanshan Fang, Yanyan Wang, Houpeng Wen, Shaoyong Zhang, and Hui Xu. "Exploration of Synergistic Pesticidal Activities, Control Effects and Toxicology Study of a Monoterpene Essential Oil with Two Natural Alkaloids." Toxins 15, no. 4 (March 25, 2023): 240. http://dx.doi.org/10.3390/toxins15040240.
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With the increasing development of pest resistances, it is not easy to achieve satisfactory control effects by using only one agrochemical. Additionally, although the alkaloid matrine (MT) isolated from Sophora flavescens is now utilized as a botanical pesticide in China, in fact, its pesticidal activities are much lower in magnitude than those of commercially agrochemicals. To improve its pesticidal activities, here, the joint pesticidal effects of MT with another alkaloid oxymatrine (OMT) (isolated from S. flavescens) and the monoterpene essential oil 1,8-cineole (CN) (isolated from the eucalyptus leaves) were investigated in the laboratory and greenhouse conditions. Moreover, their toxicological properties were also studied. Against Plutella xylostella, when the mass ratio of MT and OMT was 8/2, good larvicidal activity was obtained; against Tetranychus urticae, when the mass ratio of MT and OMT was 3/7, good acaricidal activity was obtained. Especially when MT and OMT were combined with CN, the significant synergistic effects were observed: against P. xylostella, the co-toxicity coefficient (CTC) of MT/OMT (8/2)/CN was 213; against T. urticae, the CTC of MT/OMT (3/7)/CN was 252. Moreover, the activity changes over time of two detoxification enzymes, carboxylesterase (CarE) and glutathione S-transferase (GST) of P. xylostella treated with MT/OMT (8/2)/CN, were observed. In addition, by scanning electron microscope (SEM), the toxicological study suggested that the acaricidal activity of MT/OMT (3/7)/CN may be related to the damage of the cuticle layer crest of T. urticae.
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Yadav, Shailendra, Sushma Singh, and Chitrasen Gupta. "A CONCISE OVERVIEW ON HETEROCYCLIC COMPOUNDS EXHIBITING PESTICIDAL ACTIVITIES." International Journal of Advanced Research 9, no. 08 (August 31, 2021): 989–1004. http://dx.doi.org/10.21474/ijar01/13352.
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Heterocyclic compounds are numerous and diverse group of organic compounds. Heterocycles are abundantly found in nature and express various physiological properties. Heterocycles are intricately linked to all aspects of life. There are many heterocyclic compounds currently known, and the number is constantly rising owing to extensive synthetic development and their applications. Heterocyclic compounds are used significantly in a number of areas, including biochemistry and medicinal chemistry, and some others. They are predominantly synthesized in agrochemical and pharmaceutical industries due to their potential biological activities. This review article focuses on recently synthesized heterocyclic compounds and their different pesticidal activities such as antifungal, antibacterial, antiviral, nematocidal, insecticidal, acaricidal, and herbicidal.
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Gupta, Anil K. Sen, Tapas Bhattacharya, Kanchan Hajela, Kripa Shankar, and Shakeel Ahmad. "Synthesis and pesticidal activities of some substituted 1,2,4-triazines." Pesticide Science 16, no. 1 (February 1985): 65–72. http://dx.doi.org/10.1002/ps.2780160109.
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Jahan, Nazish, Nida Hussain, Syeeda Iram Touqeer, Khalil-Ur-Rahman Khalil-Ur-Rahman, Huma Shamshad, and Naseem Abbas. "Formulation of Mentha piperita-Based Nanobiopesticides and Assessment of the Pesticidal and Antimicrobial Potential." Life 14, no. 1 (January 19, 2024): 144. http://dx.doi.org/10.3390/life14010144.
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The excessive use of synthetic pesticides has detrimental impacts on humans, non-target organisms, and the environment. Insect pest management strategies are shifting toward biopesticides, which can provide a feasible and environmentally friendly green solution to the pest problem. The key objective of the present research work was the preparation of Mentha piperita-based nanobiopesticides with enhanced stability, solubility, and pesticidal potential. Nanobiopesticides based on the Mentha piperita extract were prepared using the antisolvent precipitation method. The central composite design of response surface methodology (RSM) was utilized to optimize different process parameters, e.g., the amounts of the stabilizer and plant extract. The nanosuspension of Mentha piperita prepared with the stabilizer SLS showed a particle size of 259 nm and a polydispersity index of 0.61. The formulated biopesticides in the form of nanosuspensions showed good antibacterial activities as compared to the Mentha piperita extract against two phytopathogenic bacterial strains, Clavibacter michiganensis and Pseudomonas syringae. The M. piperita nanosuspension had higher antifungal efficacy against A. niger and F. oxysporum than the Mentha piperita extract. The M. piperita extract and its nanosuspensions were tested for pesticidal activity against the stored-grain insects Tribolium castaneum and Sitophilus oryzae. Mentha piperita-based nanobiopesticides demonstrated significantly high (p < 0.05) average mortality of 84.4% and 77.7% against Tribolium castaneum and Sitophilus oryzae, respectively. Mentha piperita-based nanobiopesticides showed enhanced pesticidal potential and could be used as a good alternative to synthetic chemical pesticides.
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Nagarkoti, Kirti, Om Prakash, Avneesh Rawat, Tanuja Kabdal, Ravendra Kumar, Ravi Mohan Srivastava, Satya Kumar, and Dharmendra Singh Rawat. "Chemo-profiling of methanolic and ether oleoresins of Salvia coccinea and in vitro pesticidal evaluation with in silico molecular docking and ADME/Tox studies." European Journal of Chemistry 14, no. 2 (June 30, 2023): 211–22. http://dx.doi.org/10.5155/eurjchem.14.2.211-222.2416.
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The objective of the present study was to examine the chemical compositions of Salvia coccinea oleoresins prepared in methanol and petroleum ether. GC-MS analysis of Salvia coccinea methanolic oleoresin (SCMO) and Salvia coccinea ether oleoresin (SCEO) resulted in the identification of 15 and 12 constituents, comprising 84.7 and 81.2% of the total composition, respectively. Both SCMO and SCEO varied in their chemical composition in terms of quantity, namely, oleic acid (22.3-25.9%), palmitic acid (8.9-8.4%), stigmasta-3,5-dien-7-one (3.4-11.8%), stigmasterol acetate (3.5-5.3%), neophytadiene (4.8-1.7%), phytol (1.6-7.8%) and phthalic acid (2.1-3.1%). In addition to the qualitative differences between SCMO and SCEO concomitantly, both oleoresins were examined for their pesticidal activities. Oleoresins demonstrated significant nematicidal activity against Meloidogyne incognita, insecticidal activity against Lipaphis erysimi, antifungal activity against Curvularia lunata, and antibacterial activity against Staphylococcus aureus. For nematicidal activity, SCMO and SCEO exhibited a high mortality of 65.66±1.69 and 54.33±1.24 and egg hatching inhibition of 26.33±1.20and 33.33±1.24 at 200 μg/mL. Similarly, SCMO and SCEO exhibited excellent insecticidal activity with 94.87±1.44 % and 86.75±1.85 % mortality at 1000 μg/mL. However, both oleoresins exhibited moderate antifungal and antibacterial activities compared to standards. Due to the quantitative difference in chemical composition and the presence of several phytoconstituents that were absent in SCEO, SCMO displayed stronger pesticidal effects than SCEO. To estimate the binding energy and structure-activity relationships between chemical constituents and pesticidal activities, in silico molecular docking and ADME/Tox studies have also been performed using a web-based online tool. On the basis of the present study, it is inferred that the herb Salvia coccinea might be a good source of phytochemicals and can be used for the development of herbal-based pesticides/formulations after proper clinical trials.
Dissertations / Theses on the topic "Pesticidal activities"
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Misra, Sutapa. "Investigation on some organophosphorus compounds having pesticidal activities." Thesis, University of North Bengal, 1991. http://hdl.handle.net/123456789/1036.
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Roy, Probir Kumar. "Studies on some organophosphorus compunds having pesticidal activities (chloro saligenin cyclic phosphoramidothionates." Thesis, University of North Bengal, 1989. http://hdl.handle.net/123456789/1133.
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Lahiri, Amaresh Chandra. "Investigation on some : 2-Alkylamido-6-Bromo-4ft-1,3,2 - Benzodioxaphosphorin 2-Sulphide : having pesticidal activities." Thesis, University of North Bengal, 1990. http://hdl.handle.net/123456789/1132.
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Clipston, Julie. "An investigation into the production by marine-derived fungi of secondary metabolites with pesticidal activities." Thesis, University of Portsmouth, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343340.
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Dasgupta, Jhinuk. "Investigation on some 2-Alkylamido 6-chloro/Nitro-4H-1, 3, 2-Benjodi-oxaphosphorin-2 - Sulphides having pesticidal activities." Thesis, University of North Bengal, 1988. http://hdl.handle.net/123456789/1130.
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Abass, Askar Kasim Sakran. "Characterization of cholinesterase activities for pesticide exposure in food animals." Thesis, University of Plymouth, 2012. http://hdl.handle.net/10026.1/1193.
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The primary aim of the work described in this thesis is to establish a foundation for the applicability of a biochemical biomarker, cholinesterase (ChE) activity in food animal species, as an instrument for evaluating exposure to pollutants as well as predicting high-level effects on public health. Secondary aims are to increase the awareness of pesticide users of anti-ChE exposure, to decide whether poisoning episodes involve anti-ChE by measuring residual effects in tissues, and to identify sources of contamination in food animal tissues. The ChE are specialized carboxylic ester hydrolases that break down esters of choline. They are classified as either acetylcholinesterase (AChE) or butyrylcholinesterase (BChE). Both AChE and BChE activities were found to be higher in cattle than in sheep and higher in erythrocytes than in plasma and serum. The anticoagulant heparin significantly affects AChE activity in plasma compared with EDTA. Of the different tissue tested, the mean of ChE activities was found to be highest in tissue from the liver, followed by lung, muscle, kidney and heart for sheep and cattle. In pigs, the ChE activities tested higher in kidney, liver, lung, muscle and heart. The effect of freezing on ChE activities in liver and muscle tissues was significant inhibition after 6 months at -80 °C, whereas decreased after 3 months at -20 °C. A technique to improve the purification of AChE in sheep tissue was developed. BW284c51 strongly reduced acetylthiocholine iodide (AcTChI) and propionylthiocholine iodide (PrTChI) hydrolysis and slightly affected that of butyrylthiocholine iodide (BuTChI) in the liver, while iso-OMPA had no significant effect for muscle BuTChI of sheep and pigs. Histochemical study of liver tissue found AChE localised mainly in the cytoplasm of the cell lining in the sinusoids. The optimal pH values of AChE and BChE in liver and muscle ranged between 7.8 and 8.5. Both AChE and BChE activities increased when increase the time course and temperature. The half maximal inhibitory concentration (IC50) was found to be higher for carbaryl than dichlorvos (DDVP) and diazinon (DZN). Very little residual AChE activity was seen in the liver, but more was found in muscles. In general, the rate constants of inhibition (ki) values for liver and muscles were increased in different pHs according to the rank order of 8.5 > 7.5 > 6.5, while in plasma it was decreased in different temperatures as follows: 20 °C > 30 °C > 40 °C. The final experiments were carried out at the rate of spontaneous reactivation (ks) of inhibited AChE by DDVP and DZN from liver and muscle was found to be higher in sheep compared to cattle and pig, while the aging of phosphorylated AChE (ka) was found to be higher in cattle compared to sheep and pig. In addition, this study indicated that the developed bispyridinium symmetric (K048) oxime seems to be promising reactivated to DDVP-inhibited AChE for sheep and pigs while HI-6 was effective in cattle.
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Ojo, Oluwaseun. "Cost efficiency analysis of pesticide use reduction in crop activities on french farms." Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL12006/document.
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Suite au Grenelle de l’environnement proposant une réduction de 50% des pesticides dans l’agriculture française, l’objet central de cette thèse est d’estimer les potentiels progrès de productivité et de diminution de ces inputs pour les grandes cultures. Dans cette perspective, le recours aux modèles d’analyse d’activités et les estimations de fonction de coût par des approches non paramétriques comme Data Envelopment Analysis (DEA) et/ou Free Disposal Hull (FDH) sont mobilisés afin d’évaluer les réductions potentielles de coût global et des dépenses en pesticide pour ce type de cultures. S’appuyant d’une part sur un panel reprenant environ 600 exploitations situées dans le département de la Meuse au cours de la période 1992-2003 et d’autre part sur un échantillon de 700 exploitations de l’Eure & Loir observées en 2008, notre recherche vise à établir une relation de dominance coût entre les technologies utilisant plus ou moins de pesticide à l’hectare. En conséquence deux fonctions de coût caractérisées par des niveaux de dépenses de pesticides à l’hectare différents (haut et faible) sont comparées. La fonction de coût non paramétrique est estimée de manière robuste pour réduire la sensibilité des résultats à l’éventuelle présence d’outliers. Les résultats indiquent que des réductions substantielles de coût sont envisageables si les agriculteurs géraient leurs inputs plus efficacement. De plus, les pratiques culturales utilisant moins de pesticide à l’hectare apparaissent plus compétitives en matière de coût. Cette conclusion indique que l’adoption de ces nouvelles pratiques économes en intrants et donc plus favorables à l’environnement serait bénéfique à la fois pour les agriculteurs et pour l’ensemble de la sociétéIn the context of the agreement of about 50% reduction in pesticide uses according to the accords du “Grenelle de l’environnement” (the Environment Round Table) in France, the central part of this study is to use some efficiency analysis to estimate the substantial productivity improvements and cost reductions on French farms. By employing Activity Analysis Models and estimating cost frontiers with non-parametric approaches such as Data Envelopment Analysis (DEA) and Free Disposal Hull (FDH)], total cost and/or pesticide expense reductions are evaluated on crop farms. Based on this, a sample of 600 and 700 farms in the Meuse and Eure & Loir departments were respectively observed over a 12 year period (1992-2003) and in year 2008. A non parametric cost function is essentially employed to assess the cost efficiency dominance between technologies using either more or less pesticide and a robust approach frontier is introduced in order to reduce the sensitivity of the cost frontier to the influence of potential outliers, thus improving the accuracy of the result. With respect to this, two cost functions characterized by a relatively lower or higher pesticide level per ha are compared. The estimated efficiency scores indicated that substantial efficiency improvements are possible on French crop farms with a strong potential for cost decreases if farmers could manage inputs more efficiently. Therefore, agricultural practices using less pesticide per ha are more cost competitive which does not only benefit the farmers but also the society, thereby promoting new agricultural practices that are more environmentally friendly
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Sagna, Bacary. "Effet d’une pollution (métaux lourds et pesticides) et d’amendement (Fumier) sur les activités enzymatiques de différents sols." Thesis, Paris Est, 2009. http://www.theses.fr/2009PEST0076.
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La fertilité, la pollution de l’écosystème sol sont devenues aujourd’hui des préoccupations etdes problèmes écologiques majeurs. L’objectif de cette étude est d’arriver à travers l’activitémicrobienne (hydrolyse de la FDA) et un large panel de 16 enzymes (phosphatases,hétérosidases, polysaccharidases, oligosaccharidases, oxydasses), à appréhender l’impact depolluants et d’amendement. Cinq sols aux caractéristiques physico-chimiques différentes ontété étudiés, et ont été soumis à différents traitements réalisés en microcosmes. Ces traitementsont porté sur l’ajout de zinc, cadmium, d’un herbicide, d’un insecticide, d’un fongicide, d’unnématicide et de fumier.L’expression des activités enzymatiques dépend fortement du type de sol. Ainsi lafraction limoneuse du sol jouerait un rôle crucial dans l’expression des enzymes telluriques. Parailleurs les résultats obtenus ont montré que des sols très proches d’un point de vu physicochimiquene le sont pas forcément au niveau enzymatique et microbien.L’ajout du fumier dans nos différents sols a entraîné quelque soit le type de sol defortes modifications positives des activités microbiennes et enzymatiques. L’effet stimulateurdu fumier sur l’activité microbienne et enzymatique dépend non seulement des paramètres dusol mais surtout de son activité initiale. Entre autre, l’impact positif du fumier est moinsmarqué dans les sols ayant des activités enzymatique ou des quantités de matière organiquefaibles. La tendance semble s’inversée concernant l’activité microbienne.L’impact des métaux lourds sur l’activité microbienne et les enzymes testées esttributaire des paramètres (argile, M.O), et de la nature des métaux lourds. Le cadmium s’avèreplus néfaste que le zinc. Si la majorité des activités enzymatiques sont diminuées par laprésence de métaux lourds d’autres en revanche ne sont pas impactées.La présence de pesticides dans nos sols révèle une grande disparité de résultat. Selon letype de sol, le type d’enzyme, une inhibition, un effet neutre ou bien une stimulation del’activité microbienne ou enzymatique par les pesticides ont été observés.Cette étude a permis de montrer que les enzymes sont très réactives aux différentesperturbations anthropiques quelque soit le type de sol considéré. Cependant cette réactivité setraduit par une très grande diversité des réponses. Cette diversité de réponse résulte d’ungrand nombre de paramètres liés aussi bien aux caractéristiques physico-chimiques quebiologiques du sol. Il n’a donc pas été possible de définir une enzyme ou groupe d’enzymesusceptible d’être utilisée comme indicateur pour l’ensemble des sols ou des traitementsFertility and pollution of the soil ecosystem have become today’s concern and major ecologicalproblems. The objective ofthis study is to estimate through microbial activity (hydrolysis ofFDA) and a wide range of 16 enzymes (phosphatases, heterosidases, polysacchridases,oligosaccharidases, oxydase), the impact of pollutants and amendment in soil. The five soilsstudied are different regarding their physical and chemical characteristics. This soils are areexposed to different treatments in microcosms. These treatments consist to pollute our soilswith heavy metals (zinc, cadmium), pesticides (herbicide, insecticide, fungicide, nematicide)or to add manure.Our results showed that the expression of enzymatic activities depends on soil type.Thus, the silt fraction of soil plays a crucial role in this expression of soil enzymes. The soilswith physico-chemical characters are very similars, have not necessarily the same enzymaticprofile and expression or microbial activity.The presence of manure on our differents soils greatly increased the enzymatic andmicrobial activities. The stimulatory effect of manure depends on soil parameters but also theinitial enzymatic and microbial soil activities. The results showed that the positive impact ofmanure is less pronouncing in soils where the initial enzyme activity and organic matterquantity are low.The impact of heavy metals on microbial activity and enzymes tested depends on soilparameters (clay, organic matter, pH, ...) and nature of heavy metal. Cadmium is more toxicand longer decreases enzymatic and microbial activities than zinc. The presence of heavymetals in soils has reduced most of enzymes activity. Other enzymes are also unchanged orincreased by the pollutants.Soil pollution by pesticides show a large disparity and diversity of results. Dependingon soil type or the enzyme tested, the diffrents results showed an increase, neutral effect ordecrease by pesticides of enzymes and microbial activities.Watever the type of soil considered, this study has shown that soil enzymes are verysensitive and responsive to human disturbance. The reactivity of telluric enzymes is manifestedby a very large diversity of responses. Diversity responses of soil enzymes is depended tophysico-chemical characters and also soil biological parameters. In this study, it is verydifficult to define one or group of enzymes as a bioindicator for all soil disturbances
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Jouni, Fatina. "Synergistic interaction earthworm-microbiota : a role in the tolerance and detoxification of pesticides?" Thesis, Avignon, 2018. http://www.theses.fr/2018AVIG0699/document.
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Les pesticides utilisés pour protéger les plantes des insectes nuisibles constituent une menace pour les organismes non cibles tels que les vers de terre. En raison de leur activité de bioturbation de sol, les vers de terre sont en contact direct avec les particules et les micro-organismes du sol, ainsi qu'avec les polluants, notamment les pesticides. L‘objectif de ce travail est d‘étudier (1) l‘effet d‘un organophosphoré (OP) «éthyl-parathion» sur la sensibilité de deux espèces de vers de terre endogés, Aporrectodea caliginosa et Allolobophora chlorotica; et (2) le rôle du microbiote intestinal, en synergie avec les voies de détoxification du ver de terre, dans la tolérance ou la détoxification des pesticides. Dans la première partie, les réponses biochimiques et comportementales ont montré que A. caliginosa est plus sensible à l'exposition à «l‘éthyl-parathion» que A. Chlorotica. Les résultats portent sur l‘analyse de biomarqueurs physiologiques (poids), biochimiques (AChE, CbEs, GST) et comportementaux (production de turricules et activité de creusement). Nous avons montré que la sensibilité de A. caliginosa semble liée à la sensibilité intrinsèque de l‘AChE à «l‘éthyl-parathion». De plus, le rôle des carboxylestérases, capables de piéger les insecticides OP, ainsi que le rôle de détoxification des GST notamment, ne semblaient pas être des mécanismes efficaces impliqués dans la tolérance de A. chlorotica. Dans la deuxième partie, nous avons caractérisé, en présence ou non d‘insecticide, le microbiote dans le sol ingéré, les turricules et les intestins des 2 vers de terre. Nos résultats ont montré des différences dans la composition microbienne de ces compartiments. A cet égard, nous avons suggéré que chacune de ces espèces hébergent un microbiote spécifique de l‘espèce dans leur intestin. Nos résultats ont notamment montré que l‘intestin du ver de terre agit comme un «filtre biologique» pour les communautés microbiennes ingérées lors du passage dans l‘intestin. A ce niveau, nous avons identifié, au niveau bactérien, quatre genres dominants dans l'intestin de A. caliginosa et deux genres dominants dans l'intestin de A. chlorotica. Nous avons notamment identifié une souche de Rhodococcus, très abondante dans l'intestin de A. chlorotica. Des études ont montré que des souches de Rhodococcus peuvent dégrader certains groupes de pesticides. Nous suggérons que la présence de cette souche pourrait contribuer à la tolérance de A. chlorotica. Enfin, nous avons montré que l‘effet de l‘éthyl-parathion sur les activités enzymatiques du sol dépend principalement de la texture du sol et non pas de la présence et/ou de l‘espèce de ver de terre.Selon nos conclusions, il est extrêmement important d'inclure plus d'une espèce pour évaluer la toxicité des insecticides organophosphorés, en raison des différences interspécifiques pouvant se produire au sein d'une même catégorie écologique. De plus, l'identification et l'analyse fonctionnelle des micro-organismes présents au niveau de l‘intestin et susceptibles d'intervenir dans la détoxication des pesticides permettraient d‘améliorer nos connaissances sur le devenir du pesticide dans l'organisme et pourraient constituer un outil important dans les programmes de bioremédiationPesticides used to protect plants from pests, threat grievously non-target organisms such as earthworms. Due to their feeding and burrowing activities, earthworms are in direct contact with soil particles and microorganisms, as well as pollutants including pesticides. This work investigated (1) the effect of an organophosphate “ethyl-parathion” on the sensitivity of two endogeic earthworms’ species, Aporrectodea caliginosa and Allolobophora chlorotica; and (2) the role of the gut-microbiota, in synergy with the earthworm’s detoxification pathways, in pesticide tolerance or detoxification. In the first part, biochemical and behavioral responses showed that A. caliginosa is more sensitive to “ethyl-parathion” exposure than A. chlorotica. The endpoints measured ranged from physiological (weight), biochemical (AChE, CbEs, GST) to behavioral biomarkers (cast production and burrowing activity). Our findings showed that the sensitivity of A. caliginosa could be mainly due to the intrinsic sensitivity of its AChE to “ethyl-parathion”. The role of the carboxylesterases, acting as bioscavenger of OP, and the role of the detoxifying enzymes GST did not appear to be efficient mechanisms involved in A. chlorotica tolerance. In the second part, we aimed to characterize the microbiome within the ingested soil, the cast and the gut tissue of A. caliginosa and A. chlorotica in control or polluted soils. Our results showed differences in the microbial composition between these compartments. In this line, we suggested that these two earthworms’ species harbor a species-specific microbiome in their gut. In particular, our findings showed that the earthworm’s gut acts as a “biological filter” for ingested microbial communities during the gut passage. At the level of the gut, we identified four dominated genus within the gut of A. caliginosa versus two dominated genus in the gut of A. chlorotica. Notably, we identified a Rhodococcus strain, which is highly abundant in the gut of A. chlorotica. Previous studies reported Rhodococcus strains for their ability to degrade some group of pesticides. We suggest that the presence of this strain could contribute to the tolerance of A. chlorotica. Finally, we showed that the effect of ethyl-parathion on soil enzyme activities mainly depend on soil texture rather than the presence and/or the species of earthworms. According to our findings, it is of considerable importance to include more than one species to assess toxicity from organophosphorus insecticides, due to the interspecific differences that can occur within the same ecological category. Moreover, the identification and the functional analysis of the microorganisms found in the earthworm’s gut and able to intervene in pesticide detoxification could enhance our knowledge about the fate of the pesticide inside the organism, and could be an important tool for bioremediation program
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Igueld, Souad. "Les acides aminoboroniques : synthèses et activités phytosanitaires." Toulouse, INPT, 1987. http://www.theses.fr/1987INPT018A.
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L'auteur a essaye tout au long de ce travail, de realiser une analogie structurale avec des acides amines en synthetisant divers acides aminoboroniques, diversifiant les substituants portes par l'atome d'azote et en modifiant la distance azote-bore, en vue d'une etude structure-activite phytosanitaire. Apres un bref apercu sur l'activite biologique que presentent les acides boroniques et plus specialement les acides aminoboroniques, il rapporte dans un premier chapitre les differents essais d'obtention d'acides -aminoboroniques. Le deuxieme chapitre est centre sur la synthese d'acides -aminoboroniques par reaction d'hydroboration. Une etude prealable de l'hydroboration d'amines allyliques avec divers substituants de l'atome d'azote est effectuee. L'acces aux acides b-aminoboroniques par reaction d'hydroboration fait l'objet du troisieme chapitre. Des intermediaires de structures enamines ont donc ete synthetises par voie photochimique
Books on the topic "Pesticidal activities"
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Washington (State). Dept. of Agriculture. and Washington State Library. Electronic State Publications., eds. Handler and worker activities in a treatment area. Olympia, WA: Washington State Dept. of Agriculture, 2003.
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Québec (Province). Direction du milieu agricole et du contrôle des pesticides., ed. Contamination du milieu aquatique et des eaux souterraines par les pesticides au Québec: Revue des différentes activités d'échantillonage réalisées de 1980 à 1991. Sainte-Foy, [Québec]: Ministère de l'environnement, Direction du milieu agricole et du contrôle des pesticides, 1992.
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United States. Congress. Senate. Committee on Environment and Public Works. Nominations to positions at the Environmental Protection Agency: Hearings before the Committee on Environment and Public Works, United States Senate, One Hundred First Congress, first session on the nominations of Timothy B. Atkeson to be Assistant Aministrator for International Activities; Linda Fisher to be Assistant Administrator for Pesticides and Toxic Substances ... July 27, October 18, and November 8, 1989. Washington: U.S. G.P.O., 1990.
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United States. Congress. Senate. Committee on Environment and Public Works. Nominations to positions at the Environmental Protection Agency: Hearings before the Committee on Environment and Public Works, United States Senate, One Hundred First Congress, first session on the nominations of Timothy B. Atkeson to be Assistant Administrator for International Activities; Linda Fisher to be Assistant Administrator for Pesticides and Toxic Substances ... July 27, October 18, and November 8, 1989. Washington: U.S. G.P.O., 1990.
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Chemical Pesticides: Mode of Action and Toxicology. CRC, 2004.
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Lippmann, Morton, and Richard B. Schlesinger. Sources of Contaminants. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190688622.003.0003.
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This chapter describes the natural sources that produce background levels of chemical contaminants in environmental media and the generally much larger anthropogenic sources in terms of: primary releases; and secondary sources resulting from chemical reactions within environmental media. There are primary sources within residences (personal care products, pesticides, the smoking of cigarettes, and unvented kitchen and bathroom effluents and heaters), in and around communities (furnace, power plant, and motor vehicle effluents), and effluents from industrial and commercial activities. Secondary sources include reactions between primary pollutants and natural and anthropogenic components in the atmosphere, hydrosphere, and lithosphere.
Book chapters on the topic "Pesticidal activities"
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Babu, J. R. "Avermectins: Biological and Pesticidal Activities." In ACS Symposium Series, 91–108. Washington, DC: American Chemical Society, 1988. http://dx.doi.org/10.1021/bk-1988-0380.ch007.
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Linders, Jan B. H. J. "Pesticide Fate Models and Their Use Focus Activities." In Modelling of Environmental Chemical Exposure and Risk, 1–15. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0884-6_1.
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Waldron, Acie C. "Pesticide Impact Assessment Program Activities in the United States." In ACS Symposium Series, 38–46. Washington, DC: American Chemical Society, 1991. http://dx.doi.org/10.1021/bk-1991-0446.ch004.
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Tiwari, Santwana, Anita Singh, and Sheo Mohan Prasad. "Regulation of Pesticide Stress on Metabolic Activities of Plant." In Metabolic Adaptations in Plants During Abiotic Stress, 99–110. Boca Raton, FL : CRC Press, Taylor & Francis Group, 2018.: CRC Press, 2018. http://dx.doi.org/10.1201/b22206-9.
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Sanchez-Hernandez, Juan C. "Biochar Mitigates the Impact of Pesticides on Soil Enzyme Activities." In Bioremediation of Agricultural Soils, 193–216. Boca Raton, FL : CRC Press, Taylor & Francis Group, 2019.: CRC Press, 2019. http://dx.doi.org/10.1201/9781315205137-10.
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Henriet, Michel. "Impact of Inerts Regulatory Issues on Agrochemical Formulation Activities." In Pesticide Formulation and Delivery Systems: 33rd Volume, “Sustainability: Contributions from Formulation Technology”, 107–17. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2014. http://dx.doi.org/10.1520/stp156920120171.
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Gurikar, Chennappa, M. K. Naik, and M. Y. Sreenivasa. "Azotobacter: PGPR Activities with Special Reference to Effect of Pesticides and Biodegradation." In Microbial Inoculants in Sustainable Agricultural Productivity, 229–44. New Delhi: Springer India, 2016. http://dx.doi.org/10.1007/978-81-322-2647-5_13.
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Kruger, Erna, Hendrik Smith, Phumzile Ngcobo, Mazwi Dlamini, and Temakholo Mathebula. "Conservation agriculture innovation systems build climate resilience for smallholder farmers in South Africa." In Conservation agriculture in Africa: climate smart agricultural development, 345–60. Wallingford: CABI, 2022. http://dx.doi.org/10.1079/9781789245745.0021.
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Abstract Introduction of Conservation Agriculture (CA) and associated climate-resilient agriculture practices within an innovation system approach, and using farmer-level experimentation and learning groups as the primary learning and social empowerment processes, has created a sustainable and expanding farming alternative for smallholders that is improving their resilience to climate change substantially. Through a knowledge co-creation process, smallholder farmers in the programme have adapted and incorporated a wide range of practices into their farming system, including minimum soil disturbance, close spacing, improved varieties, judicious use of fertilizer, pesticides and herbicides, crop diversification, intercropping and crop rotation as well as fodder production and livestock integration. They have organized themselves into learning groups, local savings and loan associations, water committees, farmer centres and cooperatives and in so doing have created innovation platforms for local value chain development. They have built ongoing relationships with other smallholders, NGOs, academic institutions, government extension services and agribusiness suppliers, and have promoted CA tirelessly within their local communities and social networks. To date, this is the most successful model for implementation of CA in smallholder farming in South Africa and, through networking and upscaling activities, is being promoted nationally as a strategic approach to smallholder adaptation and mitigation programming, in line with the Africa climate smart agriculture (CSA) Vision 25×25 (NEPAD, Malabo, June 2014).
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Kumar Mahawer, Sonu, Himani, Sushila Arya, Ravendra Kumar, and Om Prakash. "Extractions Methods and Biological Applications of Essential Oils." In Essential Oils - Advances in Extractions and Biological Applications [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102955.
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Plants produce secondary metabolites for defense and based on the biosynthetic pathway, these chemical compounds are broadly divided into three categories namely nitrogen-containing compounds, phenolic compounds, and terpenes. Essential oils and other such compounds are known for their biological activities. The extraction of essential oils is a challenging aspect for researchers in the field of natural products. Hydrodistillation is a time-consuming and very tedious method. Nowadays, accelerated solvent extraction, supercritical fluid extraction, subcritical water extraction, microwave hydrodiffusion are promising alternatives for conventional methods with several advantages. Essential oils have several biological activities in the field of pharmacological, ethnopharmacological, pesticidal, etc.
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Cave, A. "Acetogenins from Annonaceae." In Phytochemistry of Plants Used in Traditional Medicine, 227–48. Oxford University PressOxford, 1995. http://dx.doi.org/10.1093/oso/9780198577751.003.0010.
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Abstract Acetogenins from Annonaceae are a series of C-35/C-37 natural products of polyketide origin derived from fatty acids. Their structure is characterized by a long alkyl chain bearing a terminal unsaturated methyl y-lactone (sometimes rearranged to a propanone y-lactone), one or two tetrahydrofuran rings, several oxygenated substituents (hydroxyl, acetoxyl, ketone), and in some cases a double bond and/or epoxy group (Fig. 10.1). To date, they have been isolated only from the Annonaceae.Annonaceous acetogenins exhibit a broad range of potent biological activities, especially antitumoural, cytotoxic, antiparasitic, and pesticidal properties.
Conference papers on the topic "Pesticidal activities"
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Pyrko, A. N. "ENVIRONMENTALLY FRIENDLY SYNTHESIS AND BIOLOGICAL TESTING FOR PESTICIDAL ACTIVITY OF HETEROCYCLIC ANALOGS OF STEROIDS." In SAKHAROV READINGS 2022: ENVIRONMENTAL PROBLEMS OF THE XXI CENTURY. International Sakharov Environmental Institute of Belarusian State University, 2022. http://dx.doi.org/10.46646/sakh-2022-1-187-190.
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The aim of the study is the synthesis and testing for pesticidal activities of 2,3-dimethoxy-16,16-dimethyl-D-homo-8-azagona-1,3,5 (10),13-tetraene-12,17а-one and 2,3-dimethoxy-16,16-dimethyl-d-homo-8-azagona-1,3,5(10),13-tetraene-12-imino-17а-one hydrochloride which could become the basis of plant protection products. The first compound was obtained by condensation of 6,7-dimethoxy-2,3-dihydroisoquinoline with 2-acetyl-5.5-dimethylcyclohexane-1,3-dione. The second substance was synthesized by interaction of the first with ammonium chloride. The synthesized compounds were tested for certain types of pesticide activities. Both synthesized compounds showed herbicidal activity against amaranthus retroflexus, brassica rapa, abutilon theophrasti and insecticidal activity against toxoptera graminum. Hydrochloride 2,3-dimethoxy-16,16-dimethyl-D-homo-8-azagon-1,3,5(10),13-tetraene-12-imino-17a-one showed insecticidal activity against musca domestica and fungicidal activity against drechslera.
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ČESONIENĖ, Laima, Kristina LINGYTĖ, Daiva ŠILEIKIENĖ, and Midona DAPKIENĖ. "GROUNDWATER QUALITY DYNAMICS IN THE TERRITORY OF FORMER PESTICIDE WAREHOUSE." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.097.
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Pesticides are used in intensive farming to help fight plant pests and diseases (insecticides, fungicides), kill weeds (herbicides), as well as accelerate the growth of seeds (defoliants), but until 1992 pesticides were kept in improperly equipped warehouses, there was no maintenance or accounting of the pesticides. Consequently, the environment of the warehouse was often polluted. Such sources of pollution are hazardous to the environment. Economic activities in the area have been carried out from 1980 to 1994. Various agricultural chemicals have been stored and used there. Later, in 1997, chemicals (fertilizers and plant protection chemicals) stored in the territory of the warehouse have been collected and removed from the territory. During the inventory of 2009, no chemical substances were found in the territory. In 2010, an investigation carried out in the territory of the pesticide warehouse revealed unacceptable levels of pollution in the soil and the groundwater by pesticides and other toxic and neutral chemicals. In 2012, the polluted territory was cleaned eliminating the remains of buildings, and removing the soil polluted by the pesticides. The aim of the study was to evaluate the impact of the territory of the former pesticide warehouse in Kaunas District Municipality, Bubių Village on the groundwater during the period from 2012 to 2016. The results have shown that the groundwater is mostly polluted with nitrogen compounds, as well as the tendency in increase of chlorides, sodium, and calcium. Minimum and unchanging concentrations of the pesticides (DDD, DDE, DDT) were determined throughout the investigation.
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Liakh, A. V., A. O. Golovina, and A. V. Pitriuk. "ECOLOGICAL AND TOXICOLOGICAL ASSESSMENT OF SOIL CONDITIONS: ANALYSIS OF SPECIFIC TOPICAL ISSUES." In STATE AND DEVELOPMENT PROSPECTS OF AGRIBUSINESS. DSTU-PRINT, 2020. http://dx.doi.org/10.23947/interagro.2020.1.696-699.
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Due to the active development of industry and agricultural activities, more and more territories of the Russian Federation are subject to contamination by pesticides and heavy metals. In this article, special attention is paid to the ecological and Toxicological characteristics of the soils of two regions: the Moscow region, whose soils are significantly contaminated with heavy metals as a result of the activities of industrial facilities, and the Krasnodar region with a high agricultural load, which have been studied for contamination with pesticides. We analyzed not only physical and chemical changes in the soil cover, but also the consequences that negatively affect ecosystems. The prospects of using zoning as a management method in ecology are considered.
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Rosenheck, L., and D. Eberhart. "444. Exposure to Residential Pesticides: Activities of the Outdoor Residential Task Force." In AIHce 1999. AIHA, 1999. http://dx.doi.org/10.3320/1.2763313.
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Salazar, R. "278. Exposures to Petroleum Distillates and Naptha During Aerial Pesticide Application Activities." In AIHce 2001. AIHA, 2001. http://dx.doi.org/10.3320/1.2765806.
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Kovacsova, Silvia. "ENZYME ACTIVITIES AS A COMPONENT OF NUTRIENT CYCLING PROCESSES IN SOIL AMENDED WITH PESTICIDES." In 14th SGEM GeoConference on WATER RESOURCES. FOREST, MARINE AND OCEAN ECOSYSTEMS. Stef92 Technology, 2014. http://dx.doi.org/10.5593/sgem2014/b32/s13.015.
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Dobre, Lucica, and Dorina Mocuta. "INFLUENCE OF PESTICIDE USING ON THE QUALITY OF SUSTAINABLE AGRICULTURE." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022v/6.2/s25.28.
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In the era of sustainable development, the sustainability-era, the different instruments, and modern tools to carry out actions and activities that lead to an increase in the quality of life, both rural and urban environment, led us to ask the following questions: What are in fact the visible or less visible costs, in the medium and long term, when we choose to carry out activities related to agriculture that have easy and short-term success? What are the risks or benefits of such activities, in the medium and long term? Also, the topic of the present article addresses a simple question: What type of agriculture is more convenient, better in the medium and long term? Intensive agriculture with intense mechanization, which calls for intense chemicalization or organic agriculture, and the classic-traditional, green, more "rudimentary" one, if we look at it from the perspective of biotechnological discoveries, of the super-technological that takes place today in all fields of human activity? We try to shed light on these aspects and analyze them in such a way that, thinking from the perspective of sustainable development and sustainability standards agreed by common agrarian development policies, we reach levels of quality of life that bring progress, satisfaction and well-being in all areas and at all levels of human development. The research methodology of our approach is based on the conclusions of statistical studies, INS, Eurostat, on the analysis of local and European agrarian development programs, on the documentation of scientific perspectives described in specialized papers, scientific articles on the topic we are dealing with.
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Yamani, Mounia El. "1659g Occupational exposure assessment to pesticides of banana workers in the french west indies and health risks associated to their activities – matphyto project." In 32nd Triennial Congress of the International Commission on Occupational Health (ICOH), Dublin, Ireland, 29th April to 4th May 2018. BMJ Publishing Group Ltd, 2018. http://dx.doi.org/10.1136/oemed-2018-icohabstracts.1336.
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Eşitti, Bekir. "The relationships between sustainable rural development and agro-tourism: examples from Türkiye." In International Scientific-Practical Conference "Economic growth in the conditions of globalization". National Institute for Economic Research, 2023. http://dx.doi.org/10.36004/nier.cecg.ii.2023.17.11.
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Sustainable rural development aims to provide an economically, socially and environmentally sustainable development in rural areas and agro-tourism aims to evaluate the tourism potential of agricultural rural areas to make economic gains for the local people through tourism activities. Agricultural tourism integrates agricultural activities with tourism in rural areas and enables tourists to communicate with locals and experience agriculture-themed experiences. Tourism activities such as the sale of locally produced agricultural products that tourists are interested in, the organization of agricultural tours to show the production stages and accommodation revitalize the rural economy. This supports sustainable rural development. The culture, lifestyle, customs and traditions of the local people living in the countryside are introduced to the tourists and their cultural exchange takes place during agricultural tourism. In this way, interest in products that symbolize culture arises and economic benefits emerge. Agritourism, in particular, supports organic agriculture without the use of pesticides, operates in accordance with environmental sustainability principles such as sustainable agricultural practices and nature protection. This ensures the protection of natural resources in rural areas without harming the environment. In short, rural areas can become touristic attractions thanks to agricultural tourism. With the development of agricultural activities and other services in agricultural regions where tourists show great interest, new job opportunities arise, that is, economic, social and infrastructural development can be realized. From this point of view, it can be said that there is a reciprocal relationship between the understanding of sustainable rural development and agricultural tourism. Agritourism, while solving the economic, social and environmental problems in rural areas, also ensures that agriculture continues in a sustainable way. This contributes to the economy of the locals and sustainable development in rural areas. In this study, examples of sustainable rural development and agricultural tourism practices in Turkey are also discussed.
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Hamdaoui, Quentin, François Gaie-Levrel, Tatiana Macé, Sophie Vaslin-Reimann, Frédéric Flamant, and Anna Bencsik. "Development and metrological characterization of an aerosol generation device dedicated to inhalation toxicology studies: the nanopesticide case." In 19th International Congress of Metrology (CIM2019), edited by Sandrine Gazal. Les Ulis, France: EDP Sciences, 2019. http://dx.doi.org/10.1051/metrology/201907002.
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Despite the controversies surrounding the potential health effects associated with engineered nanomaterials, novel agrochemicals combining nanotechnology and pesticides are emerging. These products, named nanopesticides, are being developed to improve the efficiency of conventional agrochemicals. However, they represent an intentional anthropogenic source of nanomaterials within the different environmental compartments which constitutes a possible exposure of agricultural populations notably via the aerosols generated by farming activities. The hazard related to this new type of contaminants must be assessed by using inhalation toxicology studies that are designed to reproduce the complexity of these aerosols exposure, in order to be relevant for human health studies. In the present article, we report an experimental strategy combining both the recommendations in animal experimentation and the OECD guidelines for chemicals testing. To explore the neurotoxicity linked with the chronic exposure to aerosols generated from a nanopesticide, we develop an original device dedicated to inhalation toxicology with rodents. Through this proof of concept study, our cross-disciplinary project aims at proposing a validated methodology to study the inhalation toxicity of complex formulations represented by nanopesticides.
Reports on the topic "Pesticidal activities"
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Belkin, Shimshon, Sylvia Daunert, and Mona Wells. Whole-Cell Biosensor Panel for Agricultural Endocrine Disruptors. United States Department of Agriculture, December 2010. http://dx.doi.org/10.32747/2010.7696542.bard.
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Objectives: The overall objective as defined in the approved proposal was the development of a whole-cell sensor panel for the detection of endocrine disruption activities of agriculturally relevant chemicals. To achieve this goal several specific objectives were outlined: (a) The development of new genetically engineered wholecell sensor strains; (b) the combination of multiple strains into a single sensor panel to effect multiple response modes; (c) development of a computerized algorithm to analyze the panel responses; (d) laboratory testing and calibration; (e) field testing. In the course of the project, mostly due to the change in the US partner, three modifications were introduced to the original objectives: (a) the scope of the project was expanded to include pharmaceuticals (with a focus on antibiotics) in addition to endocrine disrupting chemicals, (b) the computerized algorithm was not fully developed and (c) the field test was not carried out. Background: Chemical agents, such as pesticides applied at inappropriate levels, may compromise water quality or contaminate soils and hence threaten human populations. In recent years, two classes of compounds have been increasingly implicated as emerging risks in agriculturally-related pollution: endocrine disrupting compounds (EDCs) and pharmaceuticals. The latter group may reach the environment by the use of wastewater effluents, whereas many pesticides have been implicated as EDCs. Both groups pose a threat in proportion to their bioavailability, since that which is biounavailable or can be rendered so is a priori not a threat; bioavailability, in turn, is mediated by complex matrices such as soils. Genetically engineered biosensor bacteria hold great promise for sensing bioavailability because the sensor is a live soil- and water-compatible organism with biological response dynamics, and because its response can be genetically “tailored” to report on general toxicity, on bioavailability, and on the presence of specific classes of toxicants. In the present project we have developed a bacterial-based sensor panel incorporating multiple strains of genetically engineered biosensors for the purpose of detecting different types of biological effects. The overall objective as defined in the approved proposal was the development of a whole-cell sensor panel for the detection of endocrine disruption activities of agriculturally relevant chemicals. To achieve this goal several specific objectives were outlined: (a) The development of new genetically engineered wholecell sensor strains; (b) the combination of multiple strains into a single sensor panel to effect multiple response modes; (c) development of a computerized algorithm to analyze the panel responses; (d) laboratory testing and calibration; (e) field testing. In the course of the project, mostly due to the change in the US partner, three modifications were introduced to the original objectives: (a) the scope of the project was expanded to include pharmaceuticals (with a focus on antibiotics) in addition to endocrine disrupting chemicals, (b) the computerized algorithm was not fully developed and (c) the field test was not carried out. Major achievements: (a) construction of innovative bacterial sensor strains for accurate and sensitive detection of agriculturally-relevant pollutants, with a focus on endocrine disrupting compounds (UK and HUJ) and antibiotics (HUJ); (b) optimization of methods for long-term preservation of the reporter bacteria, either by direct deposition on solid surfaces (HUJ) or by the construction of spore-forming Bacillus-based sensors (UK); (c) partial development of a computerized algorithm for the analysis of sensor panel responses. Implications: The sensor panel developed in the course of the project was shown to be applicable for the detection of a broad range of antibiotics and EDCs. Following a suitable development phase, the panel will be ready for testing in an agricultural environment, as an innovative tool for assessing the environmental impacts of EDCs and pharmaceuticals. Furthermore, while the current study relates directly to issues of water quality and soil health, its implications are much broader, with potential uses is risk-based assessment related to the clinical, pharmaceutical, and chemical industries as well as to homeland security.
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Wackett, Lawrence, Raphi Mandelbaum, and Michael Sadowsky. Bacterial Mineralization of Atrazine as a Model for Herbicide Biodegradation: Molecular and Applied Aspects. United States Department of Agriculture, January 1999. http://dx.doi.org/10.32747/1999.7695835.bard.
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Atrazine is a broadly used herbicide in agriculture and it was used here as a model to study the biodegradation of herbicides. The bacterium Pseudomonas sp. ADP metabolizes atrazine to carbon dioxide and ammonia and chloride. The genes encoding atrazine catabolism to cyanuric acid were cloned and expressed in Escherichia coli. The genes were designated atzA, atzB and atzC. Each gene was sequenced. The enzyme activities were characterized. AtzA is atrazine chlorohydrolase which takes atrazine to hydroxyatrizine. AtzB is hydroxyatrazine N-ethylaminohydrolase which produces N-isopropylammelide and N-ethylamine. AtzC is N-isopropylammelide N-isopropylaminohydrolase which produces cyanuric acid and N-isopropylamine. Each product was isolated and characterized to confirm their identity by chromatography and mass spectrometry. Sequence analysis indicated that each of the hydrolytic enzymes AtzA, AtzB and AtzC share identity which the aminohydrolase protein superfamily. Atrazine chlorohydrolase was purified to homogeneity. It was shown to have a kcat of 11 s-1 and a KM of 150 uM. It was shown to require a metal ion, either Fe(II), Mn(II) or Co(II), for activity. The atzA, atzB and atzC genes were shown to reside on a broad-host range plasmid in Pseudomonas sp. ADP. Six other recently isolated atrazine-degrading bacteria obtained from Europe and the United States contained homologs to the atz genes identified in Pseudomonas sp. ADP. The identity of the sequences were very high, being greater than 98% in all pairwise comparisons. This indicates that many atrazine-degrading bacteria worldwide metabolize atrazine via a pathway that proceeds through hydroxyatrazine, a metabolite which is non-phytotoxic and non-toxic to mammals. Enzymes were immobilized and used for degradation of atrazine in aqueous phases. The in-depth understanding of the genomics and biochemistry of the atrazine mineralization pathway enabled us to study factors affecting the prevalence of atrazine degradation in various agricultural soils under conservative and new agricultural practices. Moreover, Pseudomonas sp. ADP and/or its enzymes were added to atrazine-contaminated soils, aquifers and industrial wastewater to increase the rate and extent of atrazine biodegradation above that of untreated environments. Our studies enhance the ability to control the fate of regularly introduced pesticides in agriculture, or to reduce the environmental impact of unintentional releases.
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Minz, Dror, Stefan J. Green, Noa Sela, Yitzhak Hadar, Janet Jansson, and Steven Lindow. Soil and rhizosphere microbiome response to treated waste water irrigation. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7598153.bard.
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Research objectives : Identify genetic potential and community structure of soil and rhizosphere microbial community structure as affected by treated wastewater (TWW) irrigation. This objective was achieved through the examination soil and rhizosphere microbial communities of plants irrigated with fresh water (FW) and TWW. Genomic DNA extracted from soil and rhizosphere samples (Minz laboratory) was processed for DNA-based shotgun metagenome sequencing (Green laboratory). High-throughput bioinformatics was performed to compare both taxonomic and functional gene (and pathway) differences between sample types (treatment and location). Identify metabolic pathways induced or repressed by TWW irrigation. To accomplish this objective, shotgun metatranscriptome (RNA-based) sequencing was performed. Expressed genes and pathways were compared to identify significantly differentially expressed features between rhizosphere communities of plants irrigated with FW and TWW. Identify microbial gene functions and pathways affected by TWW irrigation*. To accomplish this objective, we will perform a metaproteome comparison between rhizosphere communities of plants irrigated with FW and TWW and selected soil microbial activities. Integration and evaluation of microbial community function in relation to its structure and genetic potential, and to infer the in situ physiology and function of microbial communities in soil and rhizospere under FW and TWW irrigation regimes. This objective is ongoing due to the need for extensive bioinformatics analysis. As a result of the capabilities of the new PI, we have also been characterizing the transcriptome of the plant roots as affected by the TWW irrigation and comparing the function of the plants to that of the microbiome. *This original objective was not achieved in the course of this study due to technical issues, especially the need to replace the American PIs during the project. However, the fact we were able to analyze more than one plant system as a result of the abilities of the new American PI strengthened the power of the conclusions derived from studies for the 1ˢᵗ and 2ⁿᵈ objectives. Background: As the world population grows, more urban waste is discharged to the environment, and fresh water sources are being polluted. Developing and industrial countries are increasing the use of wastewater and treated wastewater (TWW) for agriculture practice, thus turning the waste product into a valuable resource. Wastewater supplies a year- round reliable source of nutrient-rich water. Despite continuing enhancements in TWW quality, TWW irrigation can still result in unexplained and undesirable effects on crops. In part, these undesirable effects may be attributed to, among other factors, to the effects of TWW on the plant microbiome. Previous studies, including our own, have presented the TWW effect on soil microbial activity and community composition. To the best of our knowledge, however, no comprehensive study yet has been conducted on the microbial population associated BARD Report - Project 4662 Page 2 of 16 BARD Report - Project 4662 Page 3 of 16 with plant roots irrigated with TWW – a critical information gap. In this work, we characterize the effect of TWW irrigation on root-associated microbial community structure and function by using the most innovative tools available in analyzing bacterial community- a combination of microbial marker gene amplicon sequencing, microbial shotunmetagenomics (DNA-based total community and gene content characterization), microbial metatranscriptomics (RNA-based total community and gene content characterization), and plant host transcriptome response. At the core of this research, a mesocosm experiment was conducted to study and characterize the effect of TWW irrigation on tomato and lettuce plants. A focus of this study was on the plant roots, their associated microbial communities, and on the functional activities of plant root-associated microbial communities. We have found that TWW irrigation changes both the soil and root microbial community composition, and that the shift in the plant root microbiome associated with different irrigation was as significant as the changes caused by the plant host or soil type. The change in microbial community structure was accompanied by changes in the microbial community-wide functional potential (i.e., gene content of the entire microbial community, as determined through shotgun metagenome sequencing). The relative abundance of many genes was significantly different in TWW irrigated root microbiome relative to FW-irrigated root microbial communities. For example, the relative abundance of genes encoding for transporters increased in TWW-irrigated roots increased relative to FW-irrigated roots. Similarly, the relative abundance of genes linked to potassium efflux, respiratory systems and nitrogen metabolism were elevated in TWW irrigated roots when compared to FW-irrigated roots. The increased relative abundance of denitrifying genes in TWW systems relative FW systems, suggests that TWW-irrigated roots are more anaerobic compare to FW irrigated root. These gene functional data are consistent with geochemical measurements made from these systems. Specifically, the TWW irrigated soils had higher pH, total organic compound (TOC), sodium, potassium and electric conductivity values in comparison to FW soils. Thus, the root microbiome genetic functional potential can be correlated with pH, TOC and EC values and these factors must take part in the shaping the root microbiome. The expressed functions, as found by the metatranscriptome analysis, revealed many genes that increase in TWW-irrigated plant root microbial population relative to those in the FW-irrigated plants. The most substantial (and significant) were sodium-proton antiporters and Na(+)-translocatingNADH-quinoneoxidoreductase (NQR). The latter protein uses the cell respiratory machinery to harness redox force and convert the energy for efflux of sodium. As the roots and their microbiomes are exposed to the same environmental conditions, it was previously hypothesized that understanding the soil and rhizospheremicrobiome response will shed light on natural processes in these niches. This study demonstrate how newly available tools can better define complex processes and their downstream consequences, such as irrigation with water from different qualities, and to identify primary cues sensed by the plant host irrigated with TWW. From an agricultural perspective, many common practices are complicated processes with many ‘moving parts’, and are hard to characterize and predict. Multiple edaphic and microbial factors are involved, and these can react to many environmental cues. These complex systems are in turn affected by plant growth and exudation, and associated features such as irrigation, fertilization and use of pesticides. However, the combination of shotgun metagenomics, microbial shotgun metatranscriptomics, plant transcriptomics, and physical measurement of soil characteristics provides a mechanism for integrating data from highly complex agricultural systems to eventually provide for plant physiological response prediction and monitoring. BARD Report