Literatura académica sobre el tema "Pesticidal activity"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte las listas temáticas de artículos, libros, tesis, actas de conferencias y otras fuentes académicas sobre el tema "Pesticidal activity".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Artículos de revistas sobre el tema "Pesticidal activity"
1
Sun, Changjiao, Yan Wang, Xiang Zhao, Zhanghua Zeng, Bo Cui, Yue Shen, Fei Gao y Haixin Cui. "Properties of Avermectin Delivery System Using Surfactant-Modified Mesoporous Activated Carbon as a Carrier". Journal of Nanomaterials 2018 (2018): 1–6. http://dx.doi.org/10.1155/2018/3038902.
Texto completoResumen
The sensitivity of avermectin to several environmental factors, especially light, causes low pesticidal activity and environmental pollution. In this study, surfactant-modified mesoporous activated carbon (MAC) was employed to absorb avermectin (Av) in order to improve its photostability and allow for sustained release of avermectin. The results suggest that sodium dodecyl sulfate (SDS) modified MAC has excellent absorption of avermectin, and the absorption can be represented by the Langmuir isotherm model. The Av-MAC-SDS delivery system significantly improves sustained release of avermectin and also effectively inhibits the photodegradation of avermectin. These results indicate that SDS-modified MAC can be used as a carrier for avermectin to improve its pesticidal activity and reduce pesticide residues.
2
Shunmugadevi, C., S. Anbu Radhika y P. Palanisamy. "In silico and In vitro Tests of Phytocompounds Extracted from Leaves of Plectranthus amboinicus (Lour.) Spreng as Biopesticides Against Enzymes, Proteins and Selected Cell Lines of the Coleoptera Callosobruchus maculatus (Fabr., 1775)". UTTAR PRADESH JOURNAL OF ZOOLOGY 44, n.º 23 (15 de noviembre de 2023): 11–25. http://dx.doi.org/10.56557/upjoz/2023/v44i233756.
Texto completoResumen
The majority of synthetic pesticides have negative consequences on both the environment and human health, making insect pest management a global economic and ecological disaster. Crude extracts of phytocompounds from Plectranthus amboinicus were tested for their pesticidal effects on a certain enzyme cell line. An in silico molecular docking analysis of phytocompounds showed that the enzymes Glutathione S-Transferase (7RKA), Mytocontrial (5H3F), Acetylcholinesterase (7QAK), GABA receptor (7WGT), and DNA nucleotidylexotransferase (6GO4) interacted strongly with the phytocompounds. Usnic acid showed higher in-silico biopesticidal activity against Callosobruchus maculatus when compared to reference pesticide Dichlorvos and Malathion. A silica gel column chromatographic technique with appropriate solvent extract has been used to isolate the highly active components of usnic acid. In vitro studies revealed that, after 96 hours, The Usnic acid mean observed mortality percentage is 49.6% (24hr), 64.8 (48hr), 74.8% (72hr) and 87.2% (96hr). causes the maximum toxicity of Callosobruchus maculatus compared to the reference pesticides Diclorvos (84.6% & LC50 value 6.65 mg/ml) and Malathion (92% & LC50 value 5.62 mg/ml). Usnic acid exhibits promise as a pesticidal agent when compared to the reference medications. Consequently, these specific chemicals might offer substitute therapies that augment the traditional applications of the plants that are being studied.
3
Ayoub, Haytham A., Mohamed Khairy, Salaheldeen Elsaid, Farouk A. Rashwan y Hanan F. Abdel-Hafez. "Pesticidal Activity of Nanostructured Metal Oxides for Generation of Alternative Pesticide Formulations". Journal of Agricultural and Food Chemistry 66, n.º 22 (14 de mayo de 2018): 5491–98. http://dx.doi.org/10.1021/acs.jafc.8b01600.
Texto completo
4
Treacy, M., T. Miller, B. Black, I. Gard, D. Hunt y R. M. Hollingworth. "Uncoupling activity and pesticidal properties of pyrroles". Biochemical Society Transactions 22, n.º 1 (1 de febrero de 1994): 244–47. http://dx.doi.org/10.1042/bst0220244.
Texto completo
5
Přikrylová, V., G. V. Samoukina, N. V. Kandybin, L. Ujhelyiová y Ŝ. Varkonda. "Pesticidal activity of virginiamycins S1 and M1". Folia Microbiologica 37, n.º 5 (octubre de 1992): 386–88. http://dx.doi.org/10.1007/bf02815668.
Texto completo
6
Barathinivas, Ayyanar, Subramanian Ramya, Kooturan Neethirajan, Ramaraj Jayakumararaj, Chinnathambi Pothiraj, Paulraj Balaji y Caterina Faggio. "Ecotoxicological Effects of Pesticides on Hematological Parameters and Oxidative Enzymes in Freshwater Catfish, Mystus keletius". Sustainability 14, n.º 15 (3 de agosto de 2022): 9529. http://dx.doi.org/10.3390/su14159529.
Texto completoResumen
Hematological parameters and changes in stress-induced functionalities of cellular enzymes have been recognized as valuable tools for monitoring fish health and determining the toxic effects of pesticides. The present study was conducted to evaluate the toxic effect of selected pesticides viz., Ekalux (EC-25%), Impala (EC-55%), and Neemstar (EC-15%) on freshwater catfish Mystus keletius. Fish were exposed to sub-lethal concentrations (mg/L) of the selected pesticide for a period of 7, 14, 21, and 28 days. Hematological parameters viz., total erythrocyte (RBC), hemoglobin (Hb), and hematocrit (Ht) packed cell volume values decreased with an increase in exposure time to pesticides, whereas the values for parameters viz., leucocytes (WBC), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) increased significantly. A decrease in packed cell volume (PCV) and hemoglobin values coupled with decreased and deformed erythrocytes as signs of anemia were also observed. The effect of pesticides on RBC content was 1.43 (million/mm3) on day 7 and reduced to 1.18 (million/mm3) on days 14 and 21. A similar trend was found for Impala on RBC, which had an initial value of 1.36 (million/mm3) on day 7 and reached a value of 1.10 (million/mm3) on day 28. In contrast, the value of Neemstar decreased from 1.59 (million/mm3) on day 7 in control to 1.02 (million/mm3) on day 28. Data indicates that the order of toxic effect of pesticides recorded a maximum for Impala followed by Ekalux and Neemstar in the selected fish model. Likewise, the overall pattern of pesticidal activity on cellular enzymes (GDH, MDH, and SDH) recorded a maximum toxic effect for Impala followed by Ekalux and Neemstar. Results indicate that Chlorpyrifos pesticide-Impala evoked maximum toxic effect on selected tissues compared to the other two pesticides tested. Statistical analysis of the summative data using two way ANOVA was statistically significant (p-value < 0.001). The differences in the hematological parameters analyzed are attributed to the physiological acclimatization of the fish to the local conditions, which influences the energy metabolism and consequently determines the health status of the fish. Overall, Impala exhibited the highest pesticidal activity on cellular enzyme, followed by Ekalux and Neemstar. Results suggest that natural pesticides may be preferable for rice field application in terms of environmental safety.
7
Kimutai Maiyo, Wilson, Phanice Wangila, Isaac KOwino y Jacqueline Makatiani. "PESTICIDAL ACTIVITY OF CRUDE EXTRACTS OF ALOE SECUNDIFLORA,NICOTIANA TABACUM AND TEPROSIA VOGELII AGAINST FALL ARMYWORM (SPODOPTERA FRUGIPERDA)". International Journal of Advanced Research 11, n.º 09 (30 de septiembre de 2023): 388–95. http://dx.doi.org/10.21474/ijar01/17543.
Texto completoResumen
The fall armyworm (FAW),Spodoptera frugiperda (Lepidoptera: Noctuidae) is a recent invasive pest species that has successfully established across sub-Saharan Africa. Management of FAW in its native range in the Americas has led to the development of resistance to many commercial pesticides before its arrival in Africa. Synthetic pesticides are often associated with issues such as pest resistance, persistent residue, non-target toxicity, and environmental issues. Therefore, the research and development of novel, safe, and effective pesticides has become a focus in pesticide discovery. Pesticide use may therefore be ineffective for FAW control in Africa, so new and more sustainable approaches to pest management are required that can help reduce the impact of FAW pest. Pesticidal plants provide an effective and established approach to pest management in African smallholder farming and recent research has shown that their use can be cost-beneficial and sustainable. In this study, crude leave extracts of three plants aloe secundiflora, nicotiana tabacum and teprosia vogelii were evaluated against fall armyworm (spodoptera frugiperda). Two different concentrations, 30mg/L and 15mg/L were evaluated in this study against second instar FAW larvae and eggs. The results indicated that these leave extracts caused a larval and egg mortalities of different levels. On average leave extracts of aloe secundiflora, teprosia vogelii and nicotiana tabacum caused larval mortalities of 80%, 63.33% and 93.33% respectively for 30mg/L concentrations while the average larval mortalities for aloe secundiflora, teprosia vogelii and nicotiana tabacum were 26.67%, 33.33% and 80.0% respectively for the 15mg/L concentrations. The egg mortalities were relatively low compared to larval mortalities for the two concentrations used in this study. On average the leave extracts of aloe secundiflora, teprosia vogelii and nicotiana tabacum caused the egg mortalities of 16.67%, 13.33% and 43.33% respectively when 30mg/L were used while the average egg mortalities for aloe secundiflora, teprosia vogelii and nicotiana tabacum were 3.33%, 0.0% and 26.67% respectively for the 15mg/L concentrations. It follows that nicotiana tabacum showed high larval and egg mortalities for both concentrations compared to the other two leave extracts and therefore good pesticide for the control FAW larvae and eggs.
8
Nagarkoti, Kirti, Om Prakash, Avneesh Rawat, Tanuja Kabdal, Ravendra Kumar, Ravi Mohan Srivastava, Satya Kumar y 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, n.º 2 (30 de junio de 2023): 211–22. http://dx.doi.org/10.5155/eurjchem.14.2.211-222.2416.
Texto completoResumen
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.
9
Xu, Jianwei, Min Lv, Shanshan Fang, Yanyan Wang, Houpeng Wen, Shaoyong Zhang y Hui Xu. "Exploration of Synergistic Pesticidal Activities, Control Effects and Toxicology Study of a Monoterpene Essential Oil with Two Natural Alkaloids". Toxins 15, n.º 4 (25 de marzo de 2023): 240. http://dx.doi.org/10.3390/toxins15040240.
Texto completoResumen
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.
10
Fatope, Majekodunmi O., Oumar A. Adoum y Yoshio Takeda. "C18Acetylenic Fatty Acids ofXimenia americanawith Potential Pesticidal Activity". Journal of Agricultural and Food Chemistry 48, n.º 5 (mayo de 2000): 1872–74. http://dx.doi.org/10.1021/jf990550k.
Texto completoTesis sobre el tema "Pesticidal activity"
1
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.
Texto completoResumen
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
2
McGhee, Ilona. "Bioremediation and microbial activity of soil contaminated with pesticides". Thesis, University of Kent, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386119.
Texto completo
3
Borguini, Renata Galhardo. "Avaliação do potencial antioxidante e de algumas características físico-químicas do tomate (Lycopersicon esculentum) orgânico em comparação ao convencional". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/6/6133/tde-14082006-153722/.
Texto completoResumen
Objetivo: O principal objetivo desta pesquisa foi comparar os efeitos dos cultivos orgânico e convencional sobre as características físico-químicas, o teor de compostos antioxidantes, a atividade antioxidante e os resíduos de pesticidas de tomates cultivar Carmem. Considerando-se que o preparo doméstico de alimentos exerce efeitos expressivos sobre o nível de nutrientes em relação ao alimento in natura, particularmente no que tange ao teor de compostos antioxidantes e, conseqüentemente, na atividade antioxidante destes compostos, verificou-se também a influência de diversas formas de preparo doméstico para o consumo de tomates. Métodos: Os tomates foram submetidos aos seguintes tratamentos: inteiro, sem pele, sem semente, molho e purê de tomate. As amostras foram avaliadas físico-quimicamente quanto à atividade de água, sólidos solúveis totais, umidade, pH, cor, teor de ácido ascórbico, de fenólicos totais e de licopeno. As amostras foram liofilizadas e, posteriormente, submetidas ao processo de extração seqüencial para frutos, dando origem aos extratos etéreo, etanólico e aquoso. Aos extratos foram aplicados o teste do 1,1-difenil-2-picrilhidrazil (DPPH) e o sistema beta-caroteno/ácido linoléico para avaliação da atividade antioxidante in vitro. As amostras foram ainda submetidas à análise multirresíduos de pesticidas. Para análise estatística dos resultados utilizou-se análise univariada e o teste de Tukey, adotando-se um nível de significância de 5%. Resultados: O tomate orgânico inteiro e o molho apresentaram teores médios de ácido ascórbico maiores que seus similares convencionais. O tomate orgânico apresentou teor médio de fenólicos maior que o tomate convencional, para todos os produtos e preparações. Não foi possível identificar diferença entre orgânicos e convencionais quanto ao teor de licopeno, para todas as preparações e produtos avaliados. Para o extrato etéreo pelo método DPPH, verificou-se que apenas para o tomate sem semente, o orgânico apresentou atividade antioxidante maior que o convencional. Para o extrato alcoólico pelo método DPPH, apenas para o tomate sem semente não foram observadas diferenças entre orgânico e convencional. Para as demais preparações e produtos, o tomate orgânico apresentou percentual maior de atividade antioxidante que o convencional. No caso do extrato aquoso, apenas o tomate inteiro e o molho orgânico e convencional não apresentaram diferenças, para os demais modos de preparo (sem pele, sem semente e purê) o tomate orgânico apresentou percentual médio de atividade antioxidante maior que o tomate convencional. Para o extrato etéreo pelo sistema beta-caroteno/ácido linoléico, quando se comparou cultivo orgânico e convencional, observou-se que a atividade antioxidante do molho convencional foi maior que do molho orgânico. No entanto, para os tomates sem pele e sem semente, o orgânico apresentou valores médios significativamente maiores que aqueles obtidos para o tomate convencional. Para o extrato alcoólico pelo sistema beta-caroteno/ácido linoléico, não foram encontradas diferenças quando se compararam as preparações e os produtos provenientes do cultivo orgânico e convencional. No caso do extrato aquoso, o tomate orgânico apresentou maior média de atividade antioxidante para todos os modos de preparo, exceto para o molho. A forma de cultivo foi um fator determinante em relação à presença de resíduos de pesticidas (permetrina, tebuconazol e ditiocarbamatos), uma vez que o tomate orgânico preparado de diversas formas não apresentou tais resíduos. Conclusões: Devido ao limitado tamanho da amostra, nenhuma generalização pode ser estabelecida em relação ao tipo de cultivo e o valor nutricional dos tomates. No entanto, a partir dos resultados dos lotes de tomate avaliados, para a maioria dos parâmetros adotados, pode-se observar superioridade para o tomate orgânico em relação ao convencional.Objective: The main objective of this survey was to compare the cultivation effect (organic and conventional) over the physical-chemical characteristics, the content of antioxidant compounds and the antioxidant activity of tomatoes Carmen cultivar. Considering that home preparation of the food may be a significant effect over the level of nutrients in relation to a fresh food, particularly in the content of antioxidants and, consequently, in the antioxidant activity of these compounds, the influence of many ways of home prepare of tomatoes was verified. Methods: Tomatoes underwent the following treatments: whole fresh tomatoes, fresh tomatoes without the peel, fresh tomatoes without seeds, tomato sauce and tomato puree. Samples were physical-chemically analyzed for water activity, total soluble solids, water content, pH, color, ascorbic acid, total phenolics and lycopene. Samples were freeze-dried, and then underwent the sequential extraction process for fruits, resulting in ether, alcohol and water extracts. These extracts were tested by DPPH test and the beta-carotene/linoleic acid system in order to evaluate the in vitro antioxidant activity. Samples were also submitted to pesticide multi residue analysis. For the statistical analyses, ANOVA and the Tukey test were used considering a significance level of 5%. Results: The whole organic tomato and the organic sauce presented higher acid ascorbic content than their conventional counterparts. The organic tomato exhibited higher phenolics content than the conventional for all products and preparations. It was not possible to detect differences between organic and conventional in relation to the lycopene content form all preparations and products. For the ether extracts by the DPPH method, it was verified that only the organic tomato without seeds showed higher antioxidant activity than the conventional one. For the alcohol extract by the DPPH method, only the tomato without seeds not reveal differences between organic and conventional. The remaining organic preparations and products were better than the conventional. In the case of the water extract, only the whole tomato and the sauce did not show differences between the organic and the conventional, whereas the other preparations of the organic tomato exhibited higher antioxidant activity than those of the conventional tomato. For the ether extract in the beta-carotene/linoleic acid system it was verified that the conventional sauce was better than the organic one. However, the organic tomatoes without peel and seeds exhibited higher antioxidant activity than the conventional ones. For the alcohol extract in the beta-carotene/linoleic acid system no difference was detected between the organic and conventional tomato preparations and products. In the case of the water extract, the organic tomato afforded higher antioxidant activity for all types of preparations, except for the sauce. The method of cultivation was a determinant factor in relation to the presence of pesticides residues, since the organic tomato prepared in different forms did not contain these residues (permethrin, tebuconazol and dithiocarbamate). Conclusions: Due the limited size of the sample, no general statement could be made in relation to the method of cultivation and the nutritive value of tomatoes. However, for most of the parameter studied, the organically grown tomatoes ranked higher than the conventional tomatoes.
4
See, Raymond Hugh. "Clastogenic activity in urine of individuals occupationally exposed to pesticides". Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26070.
Texto completoResumen
Epidemiological evidence suggests that many human cancers may be attributed to environmental factors. Since the number of chemicals introduced into the environment is increasing at an alarming rate, measures must be taken to reduce human exposure. There is thus a growing need for the development of relevant and sensitive procedures for monitoring human exposure to environmental carcinogens and mutagens. The objective of this thesis was to evaluate the feasibility of using urine analysis to monitor individual exposure to pesticides. Pesticides are widely used chemicals in agriculture, and some are known to possess genotoxic properties.
In this study, urine samples were collected from 21 orchardists (all non-smokers) in the Okanagan Valley when they were engaged in the application of pesticides during the fruit growing seasons in 1984 and 1985. As controls, urine was collected from these same individuals during the pre-spraying as well as the post-spraying seasons. In addition, 18 individuals from an agricultural research station in the Okanagan region (including 16 non-sprayers and 2 sprayers) were recruited to provide urine samples during the same time periods as the orchardists. As controls outside the fruit growing region, individuals from Vancouver and Grand Forks, B.C. were recruited to provide one urine specimen for this study.
The urine samples were concentrated by reversed-phase high pressure liquid chromatography and then tested for their ability to induce chromosome aberrations (i.e., clastogenic activity) in cultured Chinese hamster ovary (CHO) cells. Furthermore, an attempt was made to examine the exfoliated urothelial cells for the presence of micronuclei as a potential in vivo indicator of damage by genotoxic constituents in the urine. Urine samples obtained from the orchardists 16 to 24 hours after pesticide application in 1984 resulted in levels of clastogenic activity undistinguishable from normal control limits. The failure to demonstrate increased clastogenic activity in the urine may have been due to (1) exposure to pesticides below the detection limits of the procedure, (2) the lack of genotoxicity in the agents sprayed, and (3) rapid pesticide metabolism and excretion in the urine.
In the follow-up study of 1985, all urine voids were collected on the evening of the day of pesticide spraying (i.e., within 8 hours of exposure). Using this sampling protocol, the assay results showed that (1) urine samples collected from the orchardists and the agricultural research station workers during the non-spraying periods revealed no significant difference in clastogenic activity compared to the reference control group from Vancouver and Grand Forks, and (2) clastogenic activity of urine samples collected during the spraying period in 1985 was significantly elevated for the orchardist group (P<0.001; Tukey's non-parametric multiple comparisons test) but not for the agricultural research station personnel. The high urinary clastogenic activity found for the orchardists was attributed to heavy exposure to pesticides during the mixing, formulation and application process and the lack of compliance by the sprayers to wear full protective gear in hot weather.
Cigarette smoking was another factor affecting urine clastogenicity together with pesticide exposure. Cigarette smokers from Grand Forks and the Okanagan agricultural research station demonstrated significantly higher urinary clastogenic activity than non-smokers (P<0.001; Mann-Whitney U test) . No dose-response relationship between the number of cigarettes smoked and urinary clastogenic activity was evident for the group of smokers assayed.
All of the above effects were obtained without metabolic activation in vitro, suggesting that the clastogenic agents in the urine were direct-acting. In a large proportion of the urine samples tested, low but significant (relative to solvent controls) levels of clastogenic activity were observed in the urine of unexposed non-smokers, indicating the role of other factors in the appearance of urine clastogenicity. Urinary pH and creatinine did not differ among the study groups.
No data were obtained from the analysis of micronuclei in exfoliated urothelial cells. The scarcity of cells among the subjects made it difficult to determine the frequency of micronucleated urothelial cells.
On the basis of the present research, the monitoring of urine samples for genotoxicity appears to be a useful tool for assessing human exposure to environmental carcinogens and mutagens. Urine analysis is not only valuable in qualitatively demonstrating exposure to genetically hazardous agents, but is also a promising procedure for assessing the efficacy of preventive measures which are implemented to reduce further exposure.Medicine, Faculty of
Pathology and Laboratory Medicine, Department of
Graduate
5
Dutta, Susmita. "Biochemical and molecular studies on pesticide-exposed workers of tea gardens of North Bengal". Thesis, University of North Bengal, 2018. http://hdl.handle.net/123456789/2805.
Texto completo
6
Hart, Murray. "Effects of pesticides on the soil microbial biomass and microbial activity". Thesis, University of Nottingham, 1995. http://eprints.nottingham.ac.uk/11542/.
Texto completoResumen
This thesis describes research investigating the side-effects of pesticides on soil microbial biomass and microbial activity, with particular reference to two recently developed pesticides, a fungicide, epoxiconazole, and a herbicide, quinmerac. In a dose-responsee xperiment,a pplication of thesep esticidest o a sandy loam soil, at up to 10 and 20 times field rate, had no significant effect on soil microbial biomass C or ninhydrin-reactive N, over 84 days incubation. There was also no effect on soil respiration, except for the higher rate quinmerac-treated soil, which evolved 13% lessC02-Cthan the control. The rate of mineralisation of epoxiconazole and quinmerac, and their long-term effect on soil respiration, were measured in three contrasting soils: a sandy loam, a silty clay loam, and a clay soil, using 14C -labelled active ingredients. The kinetics of the pesticides' mineralisation were quite different, epoxiconazole being hyperbolic, while quinmerac was sigmoidal. The maximum amount of mineralisation of both pesticides occurred in the silty clay loam soil, which had the lowest microbial biomass content. The mineralisation of the pesticides was increased by the addition of ryegrass, with the greatest effect in the silty clay loam soil, probably because of the large ryegrass C: biomass C ratio. The mineralisation of epoxiconazole was affected by the ryegrass amendment much more than quinmerac. Further additions of the pesticides had no significant effect on soil respiration or pesticide mineralisation. The mineralisation of epoxiconazole and quimnerac was further investigated in the silty clay loam soil, using samples with different crop management histories, and the effects of ryegrass and glucose amendment. Pesticide mineralisation was shown to be related to the amount of soil microbial biomass, indicating that the difference in mineralisation rate between the three soil types above was not due to differences in their crop management, but innate differences in soil chemistry and microbiology. Ryegrass addition stimulated the mineralisation of epoxiconazole more than quinmerac, while the reverse was true for glucose, indicating that the pesticides were being degraded by two distinct fractions of the microbial biomass. The effects of long-term cumulative field application of the pesticides benomyl, chlorfenvinphos, aldicarb, triadimefon and glyphosate, on soil microbial biomass and mineralisation of soil organic matter were investigated. The addition of aldicarb consistently increased the microbial biomass, due to its beneficial effect on crop growth, but this effect was not reflected in the rate of organic matter mineralisation. However, in general, the continued application of these pesticides for up to 19 years, at slightly higher than the recommended rates, had very little effect on the soil microbial population. The effects of epoxiconazole and triadimefon on soil ergosterol content and microbial biomass C were compared in a sandy loam soil. Both pesticides temporarily reduced soil ergosterol by about 30%, while biomass C remained largely unaffected. However, when straw was added to the soils, the inhibition of ergosterol was still evident, as was an inhibitory effect on biomass C. The measurement of soil ergosterol was more sensitive to the pesticide effects than biomass C, and could be a useful test in determining changes in fungal populations.
7
Smith, Paul Philip. "Survival, movement and activity on soil of pesticide-degrading bacterial inoculants". Thesis, University of Kent, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279177.
Texto completo
8
Borges, Luciana da Silva [UNESP]. "Biomassa, teores de nutrientes, espilantol e atividade antioxidante em plantas de jambu (Acmella ciliata Kunth) sob adubações mineral e orgânica". Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/93492.
Texto completoResumen
Made available in DSpace on 2014-06-11T19:26:40Z (GMT). No. of bitstreams: 0
Previous issue date: 2009-02-12Bitstream added on 2014-06-13T20:55:00Z : No. of bitstreams: 1
borges_ls_me_botfca.pdf: 911036 bytes, checksum: 28a62dfd0c7afee067eb1dd1f0f9ca48 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A produção orgânica é um sistema que permite alcançar bons níveis de produtividade, evitando ao mesmo tempo os riscos de contaminação química do agricultor, dos consumidores e do meio ambiente. Pelo fato da planta de jambu ser bastante utilizada como medicamento alternativo e por indústrias de cosméticos, vem aumentando o interesse devido às suas características físico-químicas. No entanto, as pesquisas sobre essa cultura ainda são muito incipientes. Existem poucos trabalhos e uma insuficiente diversidade de análises físico-químicas que possam caracterizar e diferenciar os tipos de cultivo em relação ao jambu. Assim, o objetivo do presente estudo foi analisar o óleo essencial e os compostos antioxidantes em diferentes partes de jambu (folha e inflorescência) cultivado sob adubação orgânica e mineral, além de caracterizar os minerais no solo e nas plantas, nos diferentes tipos de cultivo. O experimento foi conduzido na Fazenda Experimental São Manuel (São Manuel-SP), pertencente à Faculdade de Ciências Agronômicas - UNESP, campus de Botucatu) e na mesma época. O delineamento estatístico foi em blocos casualizados em esquema fatorial (2 x 6), duas fontes de adubação (orgânica e mineral) e seis doses de esterco de curral e uréia, com quatro repetições para todas as análises efetuadas, exceto para as características de potencial antioxidante e espilantol, que foram utilizadas três repetições. Os experimentos realizados apresentaram como tratamentos seis doses de adubação mineral (0, 30, 60, 90, 120, 150 g m-2 de uréia), aplicadas parceladas em duas vezes e seis doses de adubação orgânica (0, 2, 4, 6, 8 e 10 kg m-de esterco de curral), aplicadas no plantio. As características avaliadas foram teores de nutrientes na parte aérea, altura de plantas, massa fresca e seca, composição química do óleo essencial, teor de acido ascórbico; potencial...
The organic production it is a system that will achieve good levels of productivity, while avoiding the risk of chemical contamination of farmers, consumers and the environment. Because the plant jambu be widely used as alternative medicine and cosmetic industries, has been increasing interest due to their physical and chemical characteristics. However, the researches on this crop are still very incipient. There is little work and an insufficient variety of physical and chemical analysis that can characterize and differentiate the types of cultivation on the jambu.The purpose of this study was to analyze the essential oil and the antioxidant compounds in different parts of jambu (leaf and inflorescence) grown under organic and mineral fertilizer, and characterize the minerals in soil and plants in different types of cultivation. The experiment was conducted led in (Experimental Farm São Manuel (São Manuel-SP), belonging to the Faculty of Agricultural Sciences - UNESP, campus of Botucatu) and at the same time. The statistical design was factorial (2 x 6), two sources of fertilizer (organic and mineral) and six doses of the kraal manure and urea, with four replications for all analysis performed, except for the characteristics of potential antioxidant and spilantol, which were used three repetitions. The experiments presented treatments as six doses of conventional fertilization (0, 30, 60, 90, 120, 150 g m-2, urea), applied in two split doses of fertilizer and six non-conventional (0, 2, 4, 6, 8 and 10 kg m-2 of the kraal manure), applied at planting. The characteristics were nutrient content in shoot, plant height, fresh and dry weight, chemical composition of essential oil, ascorbic acid content, antioxidant potential, and presence of pesticides. The results show that the compounds were present in this study were trans-caryophyllene, germacrene D, L-dodecene and espatulenol and... (Complete abstract click electronic access below)
9
Model, Kathleen Jeniffer. "Pesticidas organoclorados e organofosforados no sedimento do Rio Pelotas: risco ecológico, distribuição espacial e temporal". Universidade Estadual do Oeste do Paraná, 2017. http://tede.unioeste.br/handle/tede/3076.
Texto completoResumen
Submitted by Neusa Fagundes (neusa.fagundes@unioeste.br) on 2017-09-20T20:15:24Z
No. of bitstreams: 1
Kathleen_Model2017.pdf: 1503934 bytes, checksum: 302f6ac6d413e179b8cb23b90e6830a3 (MD5)Made available in DSpace on 2017-09-20T20:15:24Z (GMT). No. of bitstreams: 1 Kathleen_Model2017.pdf: 1503934 bytes, checksum: 302f6ac6d413e179b8cb23b90e6830a3 (MD5) Previous issue date: 2017-02-16
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The highest standard of human activity is associated to agricultural and industrial activities. Thus, aquatic sediments are the most used environmental files to evaluate anthropogenic contamination from atmosphere, soil and water, due to its adsorption capacity. Inadequate and uncontrolled use of pesticides has happened in order to increase agricultural yield, although it brings forth pollution problems and serious consequences for public health. Therefore, further surveillance has been required concerning pesticides’ use and sale as well as the environment monitoring. Thus, this study aimed at evaluating Pelotas River regarding its sediment quality and taking into account compounds such as orangiochloride and organophosphorous to determine the ecological risk, spatial and temporal distributions. For this purpose, sediment samples were collected in 8 points (6 into Pelotas River and 2 into Tributaries), whose collections were carried out quarterly. This trial covered the four hydrological seasons of the year, totaling four collections that were registered with Peterson dredger. The methodology used to determine the studied pesticides was QuEChERS. The p'p'-DDT is worth mentioning from the organochlorines, since it was found in all samples. This represents that it was observed in 53.23% of the contaminated samples, with 0.158 ppb as maximum value. While Isodrin has shown the highest organochlorine concentration - 0.502 ppb. The points PEL 05 and TRI 02 showed the highest representativeness of contamination by organochlorines, caused by the slope degree of the area and by agricultural portion of each part. Methyl parathion recorded the highest representativity, with 48.4% of the total contaminated samples for organophosphates, with 2.42 ppb as maximum concentrations, while Disulfoton showed the highest concentration of this class - 2.62 ppb. The organochlorines have not shown any ecological risk. But, for organophosphates, the maximum concentration of Disulfoton pesticide has indicated a risk coefficient with significant potential for adverse effects on organisms. In the spatial and temporal distributions for organochlorines, there was some predominance of those compounds at PEL 05, PEL 04 and TRI 02 points, whereas for orgnaphosphates, points such as PEL 00, PEL 02, PEL 04 and PEL 05 were predominant. In temporal distribution, for organochlorines, eight from the ten compounds were distributed in summer, seven of them during autumn and springtime. In organophosphates, the four quantified pesticides were recorded only during autumn month. However, in springtime, three of them were representative, but in summer and winter, only two of these compounds were observed. Consequently, since Pelotas River is a Class I river, it is evident that concentrations of both classes of the studied pesticides cannot be neglected. Organophosphates are much toxic, much volatile, more used as well as the most representative ones in concentrations and they also present an ecological risk. Besides, there is an evident need to monitor these compounds in soil, sediment, water and biota, so that there is sustainability concering its use and application, aiming at improving the environmental quality and preservation of this natural resource, in this case named as Pelotas River.
O ápice da atividade humana está vinculado às atividades agrícolas e industriais, e os sedimentos aquáticos são os arquivos ambientais mais usados para a avaliação da contaminação antropogênica, oriunda da atmosfera, do solo e da água, devido a sua capacidade de adsorção. A utilização inadequada e desenfreada de agrotóxicos ocorre a fim de se aumentar a produtividade agrícola, todavia, gera problemas de poluição e consequências graves à saúde pública. Logo, são necessárias maiores fiscalizações no uso e venda desses compostos e monitoramento no ambiente. Portanto, objetivou-se avaliar a qualidade do sedimento do rio Pelotas levando em consideração a contaminação por compostos oragnoclorados, organofosforados, para determinar o risco ecológico e a distribuição espacial e temporal. Com essa finalidade, foram coletadas amostras de sedimentos em oito pontos (6 no rio Pelotas e dois em Tributários) com coletas realizadas trimestralmente. O experimento abrangeu as quatro estações hidrológicas do ano, com um total de quatro coletas efetuadas com a draga Peterson. A metodologia utilizada para determinação dos pesticidas foi a do QuEChERS. Dos organoclorados, merece destaque o p’p’-DDT, encontrado em todas as coletas, o qual representa 53,23% das amostras contaminadas, com valor máximo de 0,158 ppb. Enquanto o Isodrin apresenta a maior concentração dos organoclorados - 0,502 ppb. Os pontos PEL 05 e TRI 02 apresentam maior representatividade de contaminação por organoclorados, acarretados pelo grau de declividade do terreno e pela porção agrícola de cada área. Dos organofosforados, o Methyl parathion obteve maior representatividade com 48,4% do total das amostras contaminadas, com concentrações máximas de 2,42 ppb, enquanto o Disulfoton apresentou a maior concentração dessa classe - 2,62 ppb. Os organoclorados não apresentaram risco ecológico, mas, para os organofosforados, a concentração máxima do pesticida Disulfoton indica coeficiente de risco com potencial significativo de efeitos adversos aos organismos. Na distribuição espacial e temporal para os organoclorados, houve predominância dos compostos nos pontos PEL 05, PEL 04 e TRI 02 e, para os orgnafosforados, os pontos PEL 00, PEL 02, PEL 04 e PEL 05 foram considerados predominantes. Na distribuição temporal, para os organoclorados, dos dez compostos, oito se distribuíram no verão, sete no outono e primavera. Nos organofosforados, os quatro pesticidas quantificados foram encontrados apenas no mês de outono. Todavia, no mês da primavera, três deles foram representativos, mas, no verão e no inverno, apenas dois desses compostos foram encontrados. Dessa maneira, fica evidente, sendo o rio Pelotas de Classe I, que as concentrações de ambas as classes dos pesticidas estudados não podem ser negligenciadas, haja vista os organofosforados serem os mais tóxicos, mais voláteis, os mais usados, também os mais representativos em concentrações além de apresentarem risco ecológico. Ademais, evidencia-se a necessidade de monitoramento desses compostos no solo, sedimento, água e biota, a fim de que haja sustentabilidade no uso e aplicação, visando ao melhoramento da qualidade ambiental e à preservação desse recurso natural, que é o rio Pelotas.
10
Gillilan, Jo Anna. "IMPROVEMENT OF U.S. EPA MINIMUM RISK ESSENTIAL OILS’ PESTICIDE ACTIVITY THROUGH SURFACTANT ENHANCEMENT AND SYNERGY". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343666756.
Texto completoLibros sobre el tema "Pesticidal activity"
1
Southern African Development Coordination Conference. y Commonwealth Fund for Technical Co-operation. Industrial Development Unit., eds. Development of pesticides and insecticides manufacturing activity. London: Industrial Development Unit, Commonwealth Fund for Technical Co-operation, Commonwealth Secretariat, 1985.
Buscar texto completo
2
Montgomery, John A. Standard operating procedures for the determination of acetylcholinesterase activity. Bellingham, Wash: Huxley College of Environmental Studies, Western Washington University, 1987.
Buscar texto completo
3
Trudeau, S. Biochemical methods to determine cholinesterase activity in wildlife exposed to pesticides. Hull, Qué: Canadian Wildlife Service, 2000.
Buscar texto completo
4
Mathews, Mohan. Pesticides and the environment: A bibliography for NGO activists. New Delhi: Environmental Services Group, World Wildlife Fund, India, 1986.
Buscar texto completo
5
Peter, Matthiessen, ed. Courage for the Earth: Writers, scientists, and activists celebrate the life and writing of Rachel Carson. Boston, USA: Houghton Mifflin, 2007.
Buscar texto completo
6
Knaak, James B., Charles Timchalk y Rogelio Tornero-Velez. Parameters for pesticide QSAR and PBPK/PD models for human risk assessment. Editado por American Chemical Society y American Chemical Society. Division of Agrochemicals. Washington, DC: American Chemical Society, 2012.
Buscar texto completo
7
McConnaughey, Diane. The effects of methyl parathion on the brain cholinesterase activity of wild starlings (Sturnus vulgaris) in the Skagit Valley, Washington. Bellingham, Wash: Huxley College of Environmental Studies, Western Washington University, 1985.
Buscar texto completo
8
1953-, Horton Robert Louis, Kroll Mary, National 4-H Council (U.S.) y United States. Cooperative State Research Service., eds. Cycling back to nature. [Washington, D.C.?]: National 4-H Council, 1994.
Buscar texto completo
9
Branch, Canada Dept of Fisheries and Oceans Science. Acetylcholinesterase enzyme activity in fish sampled after the 1985 Newfoundland forest spray program for eastern hemlock looper using fenitrothion. St. John's, Nfld: Science Branch, Dept. of Fisheries and Oceans, 1987.
Buscar texto completo
10
Manzur-ul-Haque, Hashmi y United Nations Environment Programme, eds. The state of the environment. London: Butterworths, 1987.
Buscar texto completoCapítulos de libros sobre el tema "Pesticidal activity"
1
Felsot, A. S. y W. L. Pedersen. "Pesticidal Activity of Degradation Products". En ACS Symposium Series, 172–87. Washington, DC: American Chemical Society, 1991. http://dx.doi.org/10.1021/bk-1991-0459.ch013.
Texto completo
2
Nollet, Leo M. L. "Pesticidal Activity of Different Essential Oils". En Green Pesticides Handbook, 431–46. Boca Raton : Taylor & Francis, CRC Press, 2017.: CRC Press, 2017. http://dx.doi.org/10.1201/9781315153131-23.
Texto completo
3
Heuser, Justin, Craig Poffenberger, Rene Haensel y Ewald Sieverding. "Polyglycerol Esters as Adjuvants for Enhanced Pesticidal Activity". En Pesticide Formulation and Delivery Systems: 36th Volume, Emerging Trends Building on a Solid Foundation, 18–29. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2016. http://dx.doi.org/10.1520/stp159520150093.
Texto completo
4
van Frankenhuyzen, Kees. "Specificity and Cross-order Activity of Bacillus thuringiensis Pesticidal Proteins". En Bacillus thuringiensis and Lysinibacillus sphaericus, 127–72. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56678-8_10.
Texto completo
5
Kaushik, Nutan. "Pesticidal Activity of Eucalyptus Leaf Extracts against Helicoverpa armigera Larvae". En Biodiversity, 287–89. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/978-1-4419-9242-0_33.
Texto completo
6
Hariprasad, Y., C. Kathirvelu y P. Narayanasamy. "Pesticidal Activity and Future Scenario of Fly ash Dust and Fly ash-Based Herbal Pesticides in Agriculture, Household, Poultry and Grains in Storage". En Circular Economy and Fly Ash Management, 57–71. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-15-0014-5_5.
Texto completo
7
Nandihalli, Ujjana B. y Stephen O. Duke. "Structure—Activity Relationships of Protoporphyrinogen Oxidase Inhibiting Herbicides". En Porphyric Pesticides, 133–46. Washington, DC: American Chemical Society, 1994. http://dx.doi.org/10.1021/bk-1994-0559.ch010.
Texto completo
8
Weber, J. B. y S. B. Weed. "Effects of Soil on the Biological Activity of Pesticides". En Pesticides in Soil and Water, 223–56. Madison, WI, USA: Soil Science Society of America, 2015. http://dx.doi.org/10.2136/1974.pesticides.c10.
Texto completo
9
Penner, Donald y Jan Michael. "Spray SolutionpHand Glyphosate Activity". En Pesticide Formulations and Delivery Systems, 30th Volume: Regulations and Innovation, 129–36. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2010. http://dx.doi.org/10.1520/stp152720120010.
Texto completo
10
Marchini, S., L. Passerini, D. Cesareo y M. L. Tosato. "Application of Structure-Activity Analysis for Estimation of Potential Effects of Pesticides on Environmental Biological Targets". En Toxicology of Pesticides, 285–90. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-70898-5_23.
Texto completoActas de conferencias sobre el tema "Pesticidal activity"
1
Pyrko, A. N. "ENVIRONMENTALLY FRIENDLY SYNTHESIS AND BIOLOGICAL TESTING FOR PESTICIDAL ACTIVITY OF HETEROCYCLIC ANALOGS OF STEROIDS". En 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.
Texto completoResumen
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.
2
Tretiacova, Tatiana, Vladimir Todiras y Ana Gusan. "Produs nou biorațional pentru combaterea dăunătorilor în spaţii protejate". En VIIth International Scientific Conference “Genetics, Physiology and Plant Breeding”. Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2021. http://dx.doi.org/10.53040/gppb7.2021.94.
Texto completoResumen
The article presents the results of pesticidal activity study of product elaborated on the neem oil base. Bioassays were performed on aphids and spider mites in order to compare the pesticidal activity of new preparative form NEEM-01 with that of the commercial biorational products Pelecol and MatrinBio. The product NEEM- 01at a dose of 10 l/ ha has potential as aphicide and acaricide, although in terms of efficacy in controlling aphids and mites it is different. NEEM-01 was quite effective against the aphid population compared to spider mites, which are more mobile, ceasing to feed on the treated leaf. A higher mortality of pests with higher biological efficacy of NEEM- 01 was achieved after two treat-ments with an interval of 10 days between them. The results are preliminary, the research continues.
3
Chandra, J. Helan, L. F. A. Anand Raj, S. Karthick Raja Namasivayam y R. S. Arvind Bharani. "Improved pesticidal activity of fungal metabolite from nomureae rileyi with chitosan nanoparticles". En 2013 International Conference on Advanced Nanomaterials and Emerging Engineering Technologies (ICANMEET). IEEE, 2013. http://dx.doi.org/10.1109/icanmeet.2013.6609326.
Texto completo
4
Grover, Anjana, K. C. Pandey, N. K. Satija y R. M. Rai. "PESTICIDE INDUCED CHANGES IN COAGULATION AND FIBRINOLYSIS IN EXPERIMENTAL ANIMALS". En XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643071.
Texto completoResumen
A relationship between the quality of environment and incidence of human health has been recognized in recent years. While the diseases such as carcinogenesis, respiratory diseases, skin disorders are often correlated with exposure to environmental toxins, the possibility of a link between blood coagulation and chemical contaminants in food, water and air has rarely been suspected. Wide usage of DDT in public health and plant protection programmes have led to a considerably higher levels of the pesticide in the blood and body fat of Indian population. Therefore, in order to explore the possibilities of an alteration in blood coagulation and fibrinolysis in response to pesticide insult, a study was undertaken in experimental animals.Adult male albino rats were administered technical grade DDT, 100 mg per kg body weight i.p. for 3 consecutive days for acute exposure study and fed food containing the pesticide at a concentration of 100 mg per kg diet for a duration of 90 days for chronic exposure. Coagulation and fibrinolytic status was assessed at the end of exposure period. Acute exposure to DDT significantly increased platelet count but decreased wall adherence of blood while chronic exposure to DDT elevated platelet counts by 21% and increased wall adherence of blood by 28%. Plasma clotting times were found to be shortened considerably both in acute and chronically exposed animals. DDT seemed to activate both extrinsic and intrinsic pathway of coagulation as evident by marked acceleration in prothrombin time and partial thromboplastin time. Plasma fibrinogen concentrations were found to be higher by 31.6% in rats given acute treatment but 40% lower in chronically exposed animals. A marked increase in fibrinolytic activity was observed in both acutely and chronically exposed animals. Thus, administration of chlorinated pesticides like DDT seemed to have a prothrombotic effect in experimental animals.
5
Moldovan, Anna, Ion Toderaș y Natalia Munteanu-Molotievskiy. "Noi agenți bacterieni de control biologic al insectelor dăunătoare in Republica Moldova". En International symposium ”Actual problems of zoology and parasitology: achievements and prospects” dedicated to the 100th anniversary from the birth of academician Alexei Spassky. Institute of Zoology, Republic of Moldova, 2018. http://dx.doi.org/10.53937/9789975665902.70.
Texto completoResumen
Modern agriculture faces numerous problems, many of which are caused by the excessive use of synthetic pesticides to control pests. Development of a sustainable agriculture system is a priority for the Republic of Moldova, the main objectives being food security, protection of environment, support the competitiveness of local farmers on national and international market. Biological control proved to be a successful approach to the sustainable management of harmful insects. Thus, it is necessary to make continuous efforts to address the demand of business and national economy in environmentally friendly pesticide products. This study aimed to highlight new agents for biological control of insect pests based on local Bacillus thuringiensis (Bt) strains. Highlighted strains show promising results having a high insecticidal activity against lepidopteran (Lymantria dispar, Cydia pomonella and Archips rosana) and coleopteran (Neocoenorhinidius pauxillus, Phyllobius oblongus and Sitona lineatus) pest species. It therefore will allow local production of biopesticides, which will significantly reduce the final cost of the product, making it more accessible to farmers. Use of local Bt strains will also help avoid the ecological risks associated with the introduction of new organisms into ecosystems.
6
Ducrot, P., A. Bala, R. Delorme, A. Kollmann, L. Kerhoas, J. Einhorn y D. Augé. "Isolation and Pesticide Activity of Daphnanes of Lasiosiphon Kraussianus". En The 4th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2000. http://dx.doi.org/10.3390/ecsoc-4-01895.
Texto completo
7
Cota, Iuliana, Josep Maria Montornes, Magdalena Olkiewicz, Magdalena Szczech, Beata Kowalska, Albert Puigpinos, Cristobal Berna y Bartosz Tylkowski. "Use of encapsulated essential oils with antifungal activity as pesticide for organic agriculture". En 15th Mediterranean Congress of Chemical Engineering (MeCCE-15). Grupo Pacífico, 2023. http://dx.doi.org/10.48158/mecce-15.t1-o-33.
Texto completo
8
Isvoran, Adriana. "Computational study concerning the effect of some pesticides on the Proteus Mirabilis catalase activity". En 9TH INTERNATIONAL PHYSICS CONFERENCE OF THE BALKAN PHYSICAL UNION (BPU-9). AIP Publishing LLC, 2016. http://dx.doi.org/10.1063/1.4944188.
Texto completo
9
Li Ma, Tao Wang y Xu Liu. "A study on quantitative structure activity relationship between organic phosphorus pesticides and marine microalgae". En 2011 International Symposium on Water Resource and Environmental Protection (ISWREP). IEEE, 2011. http://dx.doi.org/10.1109/iswrep.2011.5893658.
Texto completo
10
Nuro, Aurel y Bledar Murtaj. "LEVELS OF SOME PRIORITY SUBSTANCES ON ADRIATIC SEA, ALBANIA". En Fourth International Scientific Conference ITEMA Recent Advances in Information Technology, Tourism, Economics, Management and Agriculture. Association of Economists and Managers of the Balkans, Belgrade, Serbia, 2020. http://dx.doi.org/10.31410/itema.2020.277.
Texto completoResumen
This study evaluated levels for organochlorine pesticides (DDTs, HCHs, Heptachlors, Aldrins and Endosulfanes), their residues, polychlorinated biphenyls (PCB) and poly aromatic hydrocarbons (PAH) in water samples of Adriatic Sea, Albanian part. Water stations were chosen near the main river estuaries of Albania (Vjosa, Semani, Shkumbini, Erzeni, Mati and Buna rivers). These rivers have catchment areas that cover almost all Albania. First, agricultural, industrial and urban waste is transported in these rivers and after that they finished in Adriatic Sea. Water samples were analyzed for a five-year period from February 2015 to December 2019. Liquid-liquid extraction was used to isolate chlorinated pollutants and a florisil column was used for clean-up procedure. Analysis of organochlorine pesticides (according to Method EPA 8081B) and 7 PCB markers was realized using GC/ECD and RTX-5 capillary column. The PAHs were isolated by liquid-liquid extraction technique and after sample concentration qualitative and quantitative analyses were performed by the GC/FID technique. Organochlorine pollutants were detected for all stations of Adriatic Sea because of new arrivals by agricultural and industrial activity in river basins. The highest levels were found near Shkumbini and Semani estuaries due to impact Myzeqeja agricultural area. New arrivals from water irrigation and rainfall influence in found levels. Degradation products of pesticides and volatile PCBs were found at higher levels for all samples analyzed. The levels of some individual organochlorine pesticides were higher than EU and Albanian norms for Semani and Shkumbini rivers. Also, PAHs were found at higher levels for Semani River because of extracting-processing industry in Patos-Marinza area. Monitoring of organic pollutants in water of Adriatic Sea should be continuous because of its importance in fishing, tourism, recreation and Albania economy overall.
Informes sobre el tema "Pesticidal activity"
1
Science, Fera. Analysis of CBD Products. Food Standards Agency, noviembre de 2022. http://dx.doi.org/10.46756/sci.fsa.cis490.
Texto completoResumen
The Food Standards Agency commissioned Fera Science Ltd. to carry out a survey to obtain a snapshot of CBD products on sale in England and Wales in order to inform FSA risk assessment of CBD products. Thirty CBD products were purchased from a range of online sellers from England and Wales. Samples comprised of two broad categories: oils and sprays, and edibles (including beverages). The sampling followed a scheme suggested by FSA. This is not a statistically representative sample of the market and instead provides a snapshot of the current market, to assist the design of future sampling and surveillance activity. There is the potential for residues of chemicals to be present in CBD products as a result of their natural occurrence in the raw material or arising from the manufacturing process, for example, mycotoxins, metals, pesticides, and the residues of solvents used to extract CBD. This study informs the FSA’s understanding of the type and levels of contaminants that may arise in CBD products. A wide range of analysis on CBD products was undertaken using accredited methods, for heavy metals, Polycyclic Aromatic Hydrocarbons (PAHs), pesticides, mycotoxins, CBD content and cannabinoid profiles. Analysis for residual solvents and additional mycotoxins was also carried out, but these were not accredited. The results of testing found the following: Heavy metals (cadmium, mercury & lead) and arsenic were not detected in the majority of samples, meaning levels were below the limits of quantification of the method. Seven samples contained lead, four samples arsenic and two samples contained cadmium. Mercury was not found in any sample. A definitive statement as to whether products exceed maximum levels cannot be made due to uncertainty as to whether products would be classified as a food (i.e. oil) or a food supplement. A low incidence of low levels of mycotoxins, with Fusarium mycotoxins found more frequently than aflatoxins and ochratoxin A, mostly at the methods reporting limit. Three samples were found to contain ochratoxin A at the methods reporting limit. A total of seven pesticide residues were found across all of the products (each product was tested for over 400 pesticides). There are no specific Maximum Residue Limits (MRL) for CBD products. One oil product was found to have PAHs above the regulated levels, if classed as a product for direct consumption. If classed as a food supplement the PAHs were within regulated levels. Three samples contained residual solvents. One product was over the MRL. Most products contained CBD close to the declared value. Two oils had substantially different levels than that declared (one higher and one lower). CBD was not detected in one of the drink products. These are potentially non-compliant with compositional and standards requirements. Delta 9-THC was detected in 87 % (26) of the samples analysed. Of these 40% (12) were found to have THC+ (the total sum of illicit cannabinoids in the product) above the 1mg threshold outlined in current Home Office guidance (Opens in a new window).
2
Gurevitz, Michael, William A. Catterall y Dalia Gordon. Learning from Nature How to Design Anti-insect Selective Pesticides - Clarification of the Interacting Face between Insecticidal Toxins and their Na-channel Receptors. United States Department of Agriculture, enero de 2010. http://dx.doi.org/10.32747/2010.7697101.bard.
Texto completoResumen
Structural details on the interacting faces of toxins and sodium channels (Navs), and particularly identification of elements that confer specificity for insects, are difficult to approach and require suitable experimental systems. Therefore, natural toxins capable of differential recognition of insect and mammalian Navs are valuable leads for design of selective compounds in insect control. We have characterized several scorpion toxins that vary in preference for insect and mammalian Navs, and identified residues important for their action. However, despite many efforts worldwide, only little is known about the receptor sites of these toxins, and particularly on differences between these sites on insect and mammalian Navs. Another problem arises from the massive overuse of chemical insecticides, which increases resistance buildup among various insect pests. A possible solution to this problem is to combine different insecticidal compounds, especially those that provide synergic effects. Our recent finding that combinations of insecticidal receptor site-3 toxins (sea anemone and scorpion alpha) with scorpion beta toxins or their truncated derivatives are synergic in toxicity to insects is therefore timely and strongly supports this approach. Our ability to produce toxins and various Navs in recombinant forms, enable thorough analysis and structural manipulations of both toxins and receptors. On this basis we propose to (1) restrict by mutagenesis the activity of insecticidal scorpion -toxins and sea anemone toxins to insects, and clarify the molecular basis of their synergic toxicity with antiinsect selective -toxins; (2) identify Nav elements that interact with scorpion alpha and sea anemone toxins and those that determine toxin selectivity to insects; (3) determine toxin-channel pairwise side-chain interactions by thermodynamic mutant cycle analysis using our large collection of mutant -toxins and Nav mutants identified in aim 2; (4) clarify the mode of interaction of truncated -toxins with insect Navs, and elucidate how they enhance the activity of insecticidal site-3 toxins. This research may lead to rational design of novel anti-insect peptidomimetics with minimal impact on human health and the environment, and will establish the grounds for a new strategy in insect pest control, whereby a combination of allosterically interacting compounds increase insecticidal action and reduce risks of resistance buildup.
3
Cytryn, Eddie, Mark R. Liles y Omer Frenkel. Mining multidrug-resistant desert soil bacteria for biocontrol activity and biologically-active compounds. United States Department of Agriculture, enero de 2014. http://dx.doi.org/10.32747/2014.7598174.bard.
Texto completoResumen
Control of agro-associated pathogens is becoming increasingly difficult due to increased resistance and mounting restrictions on chemical pesticides and antibiotics. Likewise, in veterinary and human environments, there is increasing resistance of pathogens to currently available antibiotics requiring discovery of novel antibiotic compounds. These drawbacks necessitate discovery and application of microorganisms that can be used as biocontrol agents (BCAs) and the isolation of novel biologically-active compounds. This highly-synergistic one year project implemented an innovative pipeline aimed at detecting BCAs and associated biologically-active compounds, which included: (A) isolation of multidrug-resistant desert soil bacteria and root-associated bacteria from medicinal plants; (B) invitro screening of bacterial isolates against known plant, animal and human pathogens; (C) nextgeneration sequencing of isolates that displayed antagonistic activity against at least one of the model pathogens and (D) in-planta screening of promising BCAs in a model bean-Sclerotiumrolfsii system. The BCA genome data were examined for presence of: i) secondary metabolite encoding genes potentially linked to the anti-pathogenic activity of the isolates; and ii) rhizosphere competence-associated genes, associated with the capacity of microorganisms to successfully inhabit plant roots, and a prerequisite for the success of a soil amended BCA. Altogether, 56 phylogenetically-diverse isolates with bioactivity against bacterial, oomycete and fungal plant pathogens were identified. These strains were sent to Auburn University where bioassays against a panel of animal and human pathogens (including multi-drug resistant pathogenic strains such as A. baumannii 3806) were conducted. Nineteen isolates that showed substantial antagonistic activity against at least one of the screened pathogens were sequenced, assembled and subjected to bioinformatics analyses aimed at identifying secondary metabolite-encoding and rhizosphere competence-associated genes. The genome size of the bacteria ranged from 3.77 to 9.85 Mbp. All of the genomes were characterized by a plethora of secondary metabolite encoding genes including non-ribosomal peptide synthase, polyketidesynthases, lantipeptides, bacteriocins, terpenes and siderophores. While some of these genes were highly similar to documented genes, many were unique and therefore may encode for novel antagonistic compounds. Comparative genomic analysis of root-associated isolates with similar strains not isolated from root environments revealed genes encoding for several rhizospherecompetence- associated traits including urea utilization, chitin degradation, plant cell polymerdegradation, biofilm formation, mechanisms for iron, phosphorus and sulfur acquisition and antibiotic resistance. Our labs are currently writing a continuation of this feasibility study that proposes a unique pipeline for the detection of BCAs and biopesticides that can be used against phytopathogens. It will combine i) metabolomic screening of strains from our collection that contain unique secondary metabolite-encoding genes, in order to isolate novel antimicrobial compounds; ii) model plant-based experiments to assess the antagonistic capacities of selected BCAs toward selected phytopathogens; and iii) an innovative next-generation-sequencing based method to monitor the relative abundance and distribution of selected BCAs in field experiments in order to assess their persistence in natural agro-environments. We believe that this integrated approach will enable development of novel strains and compounds that can be used in large-scale operations.
4
Wackett, Lawrence, Raphi Mandelbaum y Michael Sadowsky. Bacterial Mineralization of Atrazine as a Model for Herbicide Biodegradation: Molecular and Applied Aspects. United States Department of Agriculture, enero de 1999. http://dx.doi.org/10.32747/1999.7695835.bard.
Texto completoResumen
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.
5
Cytryn, E., Sean F. Brady y O. Frenkel. Cutting edge culture independent pipeline for detection of novel anti-fungal plant protection compounds in suppressive soils. Israel: United States-Israel Binational Agricultural Research and Development Fund, 2022. http://dx.doi.org/10.32747/2022.8134142.bard.
Texto completoResumen
Fusarium oxysporum spp. causes Panama disease in bananas and crown and root rot in an array of vegetables and field crops, but increased regulations have restricted the use of many conventional chemical pesticides, and there are a limited number of commercially available products effective against them. The soil microbiome represents a largely untapped reservoir of secondary metabolites that can potentially antagonize fungal pathogens. However, most soil bacteria cannot be cultivated using conventional techniques and therefore most of these compounds remain unexplored. The overall goal of this two-year project was to extract and characterize novel secondary metabolites from "unculturable" soil microbiomes that antagonize Fusarium and other fungal plant pathogens. Initially, the Cytryn lab at the Volcani Institute (ARO) identified candidate biosynthetic gene clusters (BGCs) encoding for potentially novel antifungal compounds (specifically non-ribosomal peptides and polyketides) in soil and plant root microbiomes using cutting-edge metagenomic platforms. Next, the Brady lab at Rockefeller University (RU) screened archived soil metagenomic cosmid libraries for these BGCs, and heterologously expressed them in suitable hosts. Finally, the Frenkel and Cytryn labs at ARO assessed the capacity of these heterologous expressed strains to antagonize Fusarium and other fungal plant pathogens. Initially tomato and lettuce were analyzed, and subsequently roots of cucumbers grown in suppressive (biochar amended) soils were targeted. We found that the composition of tomato and lettuce root BGCs are similar to each other, but significantly different from adjacent bulk soil, indicating that root bacteria possess specific secondary metabolites that are potentially associated with rhizosphere competence. BGC linked to known metabolites included various antimicrobial, (e.g., streptazone E, sessilin), antifungal (heat-stable antifungal factor- HSAF, II and ECO-02301), and insecticidal (melingmycin, orfamide A) compounds. However, over 90% of the identified BGCs were moderately to significantly different from those encoding for characterized secondary metabolites, highlighting the profusion of potentially novel secondary metabolites in both root and soil environments. Novel BGCs that were abundant in roots and remotely resembled those of antifungal compounds were transferred to RU for subsequent screening and five were identified in RU soil metagenomic cosmid libraries. Two of these clusters (BARD-1711 BARD-B481) were heterologously-expressed in a Streptomyces albus J1074 strain, and transferred to ARO. The strain harboring BARAD-B481 was found to antagonize Fusarium significantly more than the host strain, indicating that this BGCs product has antifungal activity. Future studies will need to work on chemically characterizing the BARAD-B481 BGC and progress with the above described pipeline for other interesting BGCs.
6
Ginzberg, Idit, Richard E. Veilleux y James G. Tokuhisa. Identification and Allelic Variation of Genes Involved in the Potato Glycoalkaloid Biosynthetic Pathway. United States Department of Agriculture, agosto de 2012. http://dx.doi.org/10.32747/2012.7593386.bard.
Texto completoResumen
Steroidal glycoalkaloids (SGAs) are secondary metabolites being part of the plant defense response. The two major SGAs in cultivated potato (Solanum tuberosum) are α-chaconine and α-solanine, which exhibit strong cellular lytic properties and inhibit acetylcholinesterase activity, and are poisonous at high concentrations for humans. As SGAs are not destroyed during cooking and frying commercial cultivars have been bred to contain low levels, and their content in tubers should not exceed 20 mg/100 g fresh weight. However, environmental factors can increase tuber SGA content above the safe level. The focus of the proposed research was to apply genomic approaches to identify candidate genes that control potato SGA content in order to develop tools for potato improvement by marker-assisted selection and/or transgenic approaches. To this end, the objectives of the proposal included identification of genes, metabolic intermediates and allelic variations in the potato SGAbiosynthetic pathway. The SGAs are biosynthesized by the sterol branch of the mevalonic acid/isoprenoid pathway. Transgenic potato plants that overexpress 3-hydroxy-3-methylglutaryl-CoA reductase 1 (HMG1) or squalene synthase 1 (SQS1), key enzymes of the mevalonic acid/isoprenoid pathway, exhibited elevated levels of solanine and chaconine as well as induced expression of genes downstream the pathway. These results suggest of coordinated regulation of isoprenoid (primary) metabolism and SGA secondary metabolism. The transgenic plants were further used to identify new SGA-related candidate genes by cDNA-AFLP approach and a novel glycosyltransferase was isolated. In addition, genes involved in phytosterol biosynthesis may have dual role and synthesize defense-related steroidal metabolites, such as SGAs, via lanosterol pathway. Potato lanosterol synthase sequence (LAS) was isolated and used to prepare transgenic plants with overexpressing and silencing constructs. Plants are currently being analyzed for SGA content. The dynamics of SGA accumulation in the various organs of a potato species with high SGA content gave insights into the general regulation of SGA abundance. Leaf SGA levels in S. chacoense were 10 to 20-fold greater than those of S. tuberosum. The leptines, SGAs with strong antifeedant properties against Colorado potato beetles, were present in all aerial tissues except for early and mid-developmental stages of above ground stolons, and accounted for the high SGA content of S. chacoense. These results indicate the presence of regulatory mechanisms in most tissues except in stolons that limit the levels of α-solanine and α-chaconine and confine leptine accumulation to the aerial tissues. The genomes of cultivated and wild potato contain a 4-member gene family coding for SQS. Three orthologs were cloned as cDNAs from S. chacoense and heterologously expressed in E. coli. Squalene accumulated in all E. coli lines transformed with each of the three gene constructs. Differential transcript abundance in various organs and amino acid sequence differences in the conserved domains of three isoenzymes indicate subfunctionalization of SQS activity and triterpene/sterol metabolism. Because S. chacoense and S. phureja differ so greatly for presence and accumulation of SGAs, we selected four candidate genes from different points along the biosynthetic pathway to determine if chcor phuspecific alleles were associated with SGA expression in a segregating interspecific diploid population. For two of the four genes (HMG2 and SGT2) F2 plants with chcalleles expressed significantly greater total SGAs compared with heterozygotes and those with phualleles. Although there are other determinants of SGA biosynthesis and composition in potato, the ability of allelic states at two genes to affect SGA levels confirms some of the above transgenic work where chcalleles at two other loci altered SGA expression in Desiree. Present results reveal new opportunities to manipulate triterpene/sterol biosynthesis in more targeted ways with the objective of altering SGA content for both human health concerns and natural pesticide content without disrupting the essential metabolism and function of the phytosterol component of the membranes and the growth regulating brassinosteroids.
7
VanderGheynst, Jean, Michael Raviv, Jim Stapleton y Dror Minz. Effect of Combined Solarization and in Solum Compost Decomposition on Soil Health. United States Department of Agriculture, octubre de 2013. http://dx.doi.org/10.32747/2013.7594388.bard.
Texto completoResumen
In soil solarization, moist soil is covered with a transparent plastic film, resulting in passive solar heating which inactivates soil-borne pathogen/weed propagules. Although solarization is an effective alternative to soil fumigation and chemical pesticide application, it is not widely used due to its long duration, which coincides with the growing season of some crops, thereby causing a loss of income. The basis of this project was that solarization of amended soil would be utilized more widely if growers could adopt the practice without losing production. In this research we examined three factors expected to contribute to greater utilization of solarization: 1) investigation of techniques that increase soil temperature, thereby reducing the time required for solarization; 2) development and validation of predictive soil heating models to enable informed decisions regarding soil and solarization management that accommodate the crop production cycle, and 3) elucidation of the contributions of microbial activity and microbial community structure to soil heating during solarization. Laboratory studies and a field trial were performed to determine heat generation in soil amended with compost during solarization. Respiration was measured in amended soil samples prior to and following solarization as a function of soil depth. Additionally, phytotoxicity was estimated through measurement of germination and early growth of lettuce seedlings in greenhouse assays, and samples were subjected to 16S ribosomal RNA gene sequencing to characterize microbial communities. Amendment of soil with 10% (g/g) compost containing 16.9 mg CO2/g dry weight organic carbon resulted in soil temperatures that were 2oC to 4oC higher than soil alone. Approximately 85% of total organic carbon within the amended soil was exhausted during 22 days of solarization. There was no significant difference in residual respiration with soil depth down to 17.4 cm. Although freshly amended soil proved highly inhibitory to lettuce seed germination and seedling growth, phytotoxicity was not detected in solarized amended soil after 22 days of field solarization. The sequencing data obtained from field samples revealed similar microbial species richness and evenness in both solarized amended and non-amended soil. However, amendment led to enrichment of a community different from that of non-amended soil after solarization. Moreover, community structure varied by soil depth in solarized soil. Coupled with temperature data from soil during solarization, community data highlighted how thermal gradients in soil influence community structure and indicated microorganisms that may contribute to increased soil heating during solarization. Reliable predictive tools are necessary to characterize the solarization process and to minimize the opportunity cost incurred by farmers due to growing season abbreviation, however, current models do not accurately predict temperatures for soils with internal heat generation associated with the microbial breakdown of the soil amendment. To address the need for a more robust model, a first-order source term was developed to model the internal heat source during amended soil solarization. This source term was then incorporated into an existing “soil only” model and validated against data collected from amended soil field trials. The expanded model outperformed both the existing stable-soil model and a constant source term model, predicting daily peak temperatures to within 0.1°C during the critical first week of solarization. Overall the results suggest that amendment of soil with compost prior to solarization may be of value in agricultural soil disinfestations operations, however additional work is needed to determine the effects of soil type and organic matter source on efficacy. Furthermore, models can be developed to predict soil temperature during solarization, however, additional work is needed to couple heat transfer models with pathogen and weed inactivation models to better estimate solarization duration necessary for disinfestation.
8
Chefetz, Benny, Baoshan Xing, Leor Eshed-Williams, Tamara Polubesova y Jason Unrine. DOM affected behavior of manufactured nanoparticles in soil-plant system. United States Department of Agriculture, enero de 2016. http://dx.doi.org/10.32747/2016.7604286.bard.
Texto completoResumen
The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.
9
Minz, Dror, Stefan J. Green, Noa Sela, Yitzhak Hadar, Janet Jansson y Steven Lindow. Soil and rhizosphere microbiome response to treated waste water irrigation. United States Department of Agriculture, enero de 2013. http://dx.doi.org/10.32747/2013.7598153.bard.
Texto completoResumen
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