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1,819 results on '"Díaz, Carmen"'

4. Celestial amplitudes in an ambidextrous basis

Author

Jorge-Diaz, Carmen, Pasterski, Sabrina, and Sharma, Atul

Subjects
High Energy Physics - Theory
Abstract

We start by constructing a conformally covariant improvement of the celestial light transform which keeps track of the mixing between incoming and outgoing states under finite Lorentz transformations in $\mathbb{R}^{2,2}$. We then compute generic 2, 3 and 4-point celestial amplitudes for massless external states in the ambidextrous basis prepared by composing this $\mathrm{SL}(2,\mathbb{R})$ intertwiner with the usual celestial map between momentum and boost eigenstates. The results are non-distributional in the celestial coordinates $(z,\bar{z})$ and conformally covariant in all scattering channels. Finally, we focus on the tree level 4-gluon amplitude where we present a streamlined route to the ambidextrous correlator based on Grassmannian formulae and examine its alpha space representation. In the process, we gain insights into the operator dictionary and CFT data of the holographic dual., Comment: 55 pages, 3 figures

Published
2022
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5. Expansion of the neocortex and protection from neurodegeneration by in vivo transient reprogramming

Author

Shen, Yi-Ru, Zaballa, Sofia, Bech, Xavier, Sancho-Balsells, Anna, Rodríguez-Navarro, Irene, Cifuentes-Díaz, Carmen, Seyit-Bremer, Gönül, Chun, Seung Hee, Straub, Tobias, Abante, Jordi, Merino-Valverde, Iñaki, Richart, Laia, Gupta, Vipul, Li, Hao-Yi, Ballasch, Ivan, Alcázar, Noelia, Alberch, Jordi, Canals, Josep M., Abad, Maria, Serrano, Manuel, Klein, Rüdiger, Giralt, Albert, and del Toro, Daniel

Published
2024
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6. Efficacy and safety of biological treatment for inflammatory bowel disease in elderly patients: Results from a GETECCU cohort

Author

Suárez Ferrer, Cristina, Mesonero Gismero, Francisco, Caballol, Berta, Ballester, Maria Pilar, Bastón Rey, Iria, Castaño García, Andrés, Miranda Bautista, Jose, Saiz Chumillas, Rosa, Benitez, Jose Manuel, Sanchez-Delgado, Laura, López-García, Alicia, Rubin de Celix, Cristina, Alonso Abreu, Inmaculada, Melcarne, Luigi, Plaza Santos, Rocío, Marques-Camí, Miquel, Caballero Mateos, Antonio, Gómez Díez, César, Calafat, Margalida, Galan, Horacio Alonso, Vega Vilaamil, Pablo, Castro Senosiain, Beatriz, Guerro Moya, Andrea, Rodriguez Diaz, Carmen Yolanda, Spicakova, Katerina, Manceñido Marcos, Noemi, Molina, Gema, de Castro Parga, Luisa, Rodriguez Angulo, Andres, Cuevas del Campo, Lidia, Rodriguez Grau, Maria del Carmen, Ramirez, Fernando, Gomez Pastrana, Barbara, Gonzalez Partida, Irene, Botella Mateu, Belen, Peña Gonzalez, Elena, Iyo, Eduardo, Elosua Gonzalez, Alfonso, Sainz Arnau, Empar, Hernandez Villalba, Luis, Perez Galindo, Pablo, Torrealba Medina, Leyanira, Monsalve Alonso, Sara, Olmos Perez, Jose Antonio, Dueñas Sadornil, Carmen, Garcia Ramirez, Laura, Martín-Arranz, María Dolores, López Sanroman, Antonio, Fernández, Agnès, Merino Murgui, Victor, Calviño Suárez, Cristina, Flórez-Diez, Pablo, Lobato Matilla, María Elena, Sicilia, Beatriz, Soto Escribano, Pilar, Maroto Martin, Carlos, Mañosa, Míriam, and Barreiro-De Acosta, Manuel

Published
2024
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11. On the Spectrum of Pure Higher Spin Gravity

Author

Alday, Luis F., Bae, Jin-Beom, Benjamin, Nathan, and Jorge-Diaz, Carmen

Subjects
High Energy Physics - Theory
Abstract

We study the spectrum of pure massless higher spin theories in $AdS_3$. The light spectrum is given by a tower of massless particles of spin $s=2,\cdots,N$ and their multi-particles states. Their contribution to the torus partition function organises into the vacuum character of the ${\cal W}_N$ algebra. Modular invariance puts constraints on the heavy spectrum of the theory, and in particular leads to negative norm states, which would be inconsistent with unitarity. This negativity can be cured by including additional light states, below the black hole threshold but whose mass grows with the central charge. We show that these states can be interpreted as conical defects with deficit angle $2\pi(1-1/M)$. Unitarity allows the inclusion of such defects into the path integral provided $M \geq N$., Comment: 33 pages, v2: references added, v3: minor typos corrected, published version

Published
2020
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21. Optimization of fungicidal and acaricidal metabolite production by endophytic fungus Aspergillus sp. SPH2

Author

Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Díaz, Carmen E. [0000-0003-1992-3545], Imperial, Juan [0000-0002-5002-6458], González-Coloma, Azucena [0000-0001-5124-664X], Reyes Castillo, Nicolás, Díaz, Carmen E., Andrés, María Fé, Imperial, Juan, Valcárcel Sancho, Félix María, González-Coloma, Azucena, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Díaz, Carmen E. [0000-0003-1992-3545], Imperial, Juan [0000-0002-5002-6458], González-Coloma, Azucena [0000-0001-5124-664X], Reyes Castillo, Nicolás, Díaz, Carmen E., Andrés, María Fé, Imperial, Juan, Valcárcel Sancho, Félix María, and González-Coloma, Azucena

Abstract

The endophytic fungus Aspergillus sp. SPH2 was isolated from the stems of the endemic plant Bethencourtia palmensis and its extracts were found to have strong fungicidal effects against Botrytis cinerea and ixodicidal effects against Hyalomma lusitanicum at different fermentation times. In this study, the fungus was grown using three different culture media and two methodologies, Microparticulate Enhancement Cultivation (MPEC) and Semi-Solid-State Fermentation (Semi-SSF), to increase the production of secondary metabolites during submerged fermentation. The addition of an inert support to the culture medium (Semi-SSF) resulted in a significant increase in the extract production. However, when talcum powder was added to different culture media, unexpected results were observed, with a decrease in the production of the biocompounds of interest. Metabolomic analyses showed that the production of aspergillic, neoaspergillic, and neohydroxyaspergillic acids peaked in the first few days of fermentation, with notable differences observed among the methodologies and culture media. Mellein production was particularly affected by the addition of an inert support to the culture medium. These results highlight the importance of surface properties and morphology of spores and mycelia during fermentation by this fungal species.

Published
2024

24. Abordaje quirúrgico en un paciente con carcinoma epidermoide de células basaloides en cavidad nasal con invasión al cerebro.

Author

Prado Hernández, Ezri Natanael, Ferrufino Mejía, Bill Roy, Ferrufino Mejía, Milivoy Alan, Vázquez Nieves, José Roberto, and Vargas Díaz, Carmen Inés

Abstract

Copyright of Revista de la Facultad de Medicina de la UNAM is the property of UNAM, Facultad de Medicina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2024
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25. Clipaje de aneurisma cerebral en un paciente con poliquistosis renal previo a un trasplante renal: A propósito de un caso.

Author

Prado Hernández, Ezri Natanael, Ferrufino Mejía, Bill Roy, Ferrufino Mejía, Milivoy Alan, Vázquez Nieves, José Roberto, and Vargas Díaz, Carmen Inés

Abstract

Copyright of Revista de la Facultad de Medicina de la UNAM is the property of UNAM, Facultad de Medicina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2024
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26. Angioedema Due to Acquired Deficiency of C1-Inhibitor: A Cohort Study in Spain and a Comparison With Other Series

Author

Baeza, Maria L., González-Quevedo, Teresa, Caballero, Teresa, Guilarte, Mar, Lleonart, Ramon, Varela, Susana, Castro, Monica, Díaz, Carmen, Escudero, Elena, García, Marimar G., Laffond, Elena, Muñoz-Bellido, Francisco.J., Núñez, Ramon, Prior, Nieves, Sala-Cunill, Anna, Sáenz de San Pedro, Blanca, and Prieto-García, Alicia

Published
2022
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30. Deflamin Attenuated Lung Tissue Damage in an Ozone-Induced COPD Murine Model by Regulating MMP-9 Catalytic Activity

Author

Baltazar-García, Elia Ana, primary, Vargas-Guerrero, Belinda, additional, Lima, Ana, additional, Boavida Ferreira, Ricardo, additional, Mendoza-Magaña, María Luisa, additional, Ramírez-Herrera, Mario Alberto, additional, Baltazar-Díaz, Tonatiuh Abimael, additional, Domínguez-Rosales, José Alfredo, additional, Salazar-Montes, Adriana María, additional, and Gurrola-Díaz, Carmen Magdalena, additional

Published
2024
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34. Variations in Neonatal Length of Stay of Babies Born Extremely Preterm: An International Comparison Between iNeo Networks

Author

Lui, Kei, Marshall, Peter, Schmidt, Peter, Dhawan, Anjali, Korostenski, Larissa, Travadi, Javeed Travadi, Sharp, Mary, Gill, Andy, Pillow, Jane, Stack, Jacqueline, Birch, Pita, Nothdurft, Karen, Cooke, Lucy, Casalaz, Dan, Holberton, Jim, Stewart, Alice, Downe, Lyn, Stewart, Michael, Berry, Andrew, Hunt, Rod, Morris, Peter, Paoli, Tony De, Bolisetty, Srinivas, Paradisis, Mary, Greenhalgh, Mark, Koorts, Pieter, Kuschel, Carl, Jacobs, Sue, Doyle, Lex, Craven, John, Numa, Andrew, Carlisle, Hazel, Badawi, Nadia, Popat, Himanshu, Koh, Guan, Davis, Jonathan, Luig, Melissa, Headley, Bevan, Andersen, Chad, Ng, Linda, Chambers, Georgina, Austin, Nicola, Lynn, Adrienne, Darlow, Brian, Edmonds, Liza, Mildenhall, Lindsay, Buksh, Mariam, Battin, Malcolm, Boom, Jutta van den, Richardson, Vaughan, Barker, David, Hammond, Barbara, Rajadurai, Victor Samuel, Lam, Simon, Fung, Genevieve, Shah, Prakesh S., Beltempo, Marc, Kanungo, Jaideep, Ting, Joseph, Cieslak, Zenon, Sherlock, Rebecca, Mehrem, Ayman Abou, Toye, Jennifer, Aziz, Khalid, Fajardo, Carlos, Bodani, Jaya, Strueby, Lannae, Seshia, Mary, Louis, Deepak, Alvaro, Ruben, Mukerji, Amit, Da Silva, Orlando, Adie, Mohammad, Lee, Kyong-Soon, Ng, Eugene, Lemyre, Brigitte, Daboval, Thierry, Khurshid, Faiza, Pelausa, Ermelinda, Barrington, Keith, Lapoint, Anie, Ethier, Guillaume, Drolet, Christine, Piedboeuf, Bruno, Claveau, Martine, St-Hilaire, Marie, Bertelle, Valerie, Masse, Edith, Canning, Roderick, Makary, Hala, Ojah, Cecil, Monterrosa, Luis, Emberley, Julie, Afifi, Jehier, Kajetanowicz, Andrzej, Lee, Shoo K., Metsäranta, Marjo, Lehtonen, Liisa, Tammela, Outi, Sankilampi, Ulla, Saarela, Timo, Morag, Iris, Zangen, Shmuel, Smolkin, Tatyana, Mimouni, Francis, Bader, David, Rothschild, Avi, Strauss, Zipora, Felszer, Clari, Omari, Hussam, Tov-Friedman, Smadar Even, Bar-Oz, Benjamin, Feldman, Michael, Saad, Nizar, Flidel-Rimon, Orna, Weisbrod, Meir, Lubin, Daniel, Litmanovitz, Ita, Kugelman, Amir, Shinwell, Eric, Klinger, Gil, Nijim, Yousif, Bin-Nun, Alona, Golan, Agneta, Mandel, Dror, Fleisher-Sheffer, Vered, Oron, Anat, Bakhrakh, Lev, Hattori, Satoshi, Shirai, Masaru, Ishioka, Toru, Mori, Toshihiko, Amizuka, Takasuke, Huchimukai, Toru, Yoshida, Hiroshi, Sasaki, Ayako, Shimizu, Junichi, Nakamura, Toshihiko, Maruyama, Mami, Matsumoto, Hiroshi, Hosokawa, Shinichi, Taki, Atsuko, Nakagawa, Machiko, Ko, Kyone, Uozumi, Azusa, Nakata, Setsuko, Shimazaki, Akira, Yoda, Tatsuya, Numata, Osamu, Imamura, Hiroaki, Kobayashi, Azusa, Tokuriki, Shuko, Uchida, Yasushi, Arai, Takahiro, Ito, Mitsuhiro, Ieda, Kuniko, Ono, Toshiyuki, Hayashi, Masashi, Maki, Kanemasa, Yamakawa, MieToru, Kawai, Masahiko, Fujii, Noriko, Shiomi, Kozue, Nozaki, Koji, Wada, Hiroshi, Kim, Taho, Tokunaga, Yasuyuki, Takatera, Akihiro, Oshima, Toshio, Sumida, Hiroshi, Michinomae, Yae, Kusumoto, Yoshio, Yoshimoto, Seiji, Morisawa, Takeshi, Ohashi, Tamaki, Takahashi, Yukihiro, Sugimoto, Moriharu, Ono, Noriaki, Miyagawa, Shinichiro, Saijo, Takahiko, Yamagami, Takashi, Koyano, Kosuke, Kobayashi, Shoko, Kanda, Takeshi, Sakemi, Yoshihiro, Aoki, Mikio, Iida, Koichi, Goshi, Mitsushi, Maruyama, Yuko, Avila-Alvarez, Alejandro, Fernandez-Trisac, José Luis, Pico, M<ce:sup loc='post">a</ce:sup> Luz Couce, Fernández Seara, María José, Gutiérrez, Andrés Martínez, Vizcaíno, Carolina, Iglesias, Miriam Salvador, Zaplana, Honorio Sánchez, Colomer, Belén Fernández, García López, José Enrique, Mozo, Rafael García, González Martínez, M. Teresa, Sebastián, M<ce:sup loc='post">a</ce:sup> Dolores Muro, Carbonell, Marta Balart, Barnusell, Joan Badia, Puiggròs, Mònica Domingo, Aloy, Josep Figueras, Mussons, Francesc Botet, Sanz, Israel Anquela, Galiana, Gemma Ginovart, Coroleu, W., Iriondo, Martin, Vilella, Laura Castells, Porta, Roser, Demestre, Xavier, Nadal, Silvia Martínez, de Frutos Martínez, Cristina, López Cuesta, María Jesús, Mora, Dolores Esquivel, Tardío, Joaquín Ortiz, Benavente, Isabel, Alonso, Almudena, Olmos, Ramón Aguilera, García Cabezas, Miguel A., Jiménez, M<ce:sup loc='post">a</ce:sup> Dolores Martínez, Caballero, M<ce:sup loc='post">a</ce:sup> Pilar Jaraba, Díaz, M<ce:sup loc='post">a</ce:sup> Dolores Ordoñez, Fagundo, Alberto Trujillo, Canals, Lluis Mayol, García-Muñoz Rodrigo, Fermín, Martí, Lourdes Urquía, Moreno Galdo, María Fernanda, Suazo, José Antonio Hurtado, López, Eduardo Narbona, Fernández, José Uberos, Cortajarena Altuna, Miguel A., Zuriarrain, Oihana Muga, Navarro, David Mora, Domínguez, María Teresa, Ruiz del Prado, M<ce:sup loc='post">a</ce:sup> Yolanda, Díez, Inés Esteban, Palau Benavides, María Teresa, Lapeña, Santiago, Prada, Teresa, Mir, Eduard Soler, Sánchez, Araceli Corredera, Vega, Enrique Criado, Prado, Náyade del, Fernández, Cristina, Vilaplana, Lucía Cabanillas, Pérez, Irene Cuadrado, Gómez, Luisa López, Comeche, Laura Domingo, Martín, Isabel Llana, Armengod, Carmen González, Labián, Carmen Muñoz, Muñoz, M<ce:sup loc='post">a</ce:sup> José Santos, Bravo, Dorotea Blanco, Pérez, Vicente, Fernández, M<ce:sup loc='post">a</ce:sup> Dolores Elorza, González, Celia Díaz, Segura, Susana Ares, Azorín, Manuela López, Jimenez, Ana Belén, Sánchez-Tamayo, Tomás, Moreno, Elías Tapia, González, María, Sánchez Martínez, José Enrique, Lloreda García, José María, Orayen, Concepción Goñi, González, Javier Vilas, Albo, María Suárez, Colmenero, Eva González, Gutiérrez González, Elena Pilar, Vacas del Arco, Beatriz, Fernández, Josefina Márquez, Gordillo, Laura Acosta, Asensio, Mercedes Granero, Díaz, Carmen Macías, Albújar, Mar, Jorge, Pedro Fuster, Romero, Sabina, Falero, Mónica Rivero, Escobar Izquierdo, Ana Belén, Capell, Javier Estañ, Macián, M<ce:sup loc='post">a</ce:sup> Isabel Izquierdo, Vicente, M<ce:sup loc='post">a</ce:sup> Mar Montejo, Caballero, Raquel Izquierdo, Martínez, M<ce:sup loc='post">a</ce:sup> Mercedes, Euba, Aintzane, Serna, Amaya Rodríguez, López de Heredia Goya, Juan María, Legorburu, Alberto Pérez, Amorós, Ana Gutiérrez, Marugán Isabel, Víctor Manuel, González, Natalio Hernández, Gracia, Segundo Rite, Faci, M<ce:sup loc='post">a</ce:sup> Purificación Ventura, Villagrasa, M<ce:sup loc='post">a</ce:sup> Pilar Samper, Kofron, Jiri, Brodd, Katarina Strand, Odlind, Andreas, Alberg, Lars, Arwehed, Sofia, Hafström, Ola, Kasemo, Anna, Nederman, Karin, Åhman, Lars, Ingemarsson, Fredrik, Petersson, Henrik, Thurn, Pernilla, Albinsson, Eva, Selander, Bo, Abrahamsson, Thomas, Heimdahl, Ingela, Sveinsdottir, Kristbjorg, Wejryd, Erik, Hedlund, Anna, Söderberg, Maria Katarina, Navér, Lars, Brune, Thomas, Bäckström, Jens, Robinson, Johan, Farooqi, Aijaz, Normann, Erik, Fredriksson, Magnus, Palm, Anders, Rosenqvist, Urban, Walde, Bengt, Hagman, Cecilia, Ohlin, Andreas, Florell, Rein, Smedsaas-Löfvenberg, Agneta, Adams, Mark, Meyer, Philipp, Kusche, Rachel, Schulzke, Sven, Nelle, Mathias, Wagner, Bendicht, Riedel, Thomas, Kaczala, Grégoire, Pfister, Riccardo E., Tolsa, Jean-François, Roth, Matthias, Stocker, Martin, Laubscher, Bernhard, Malzacher, Andreas, Micallef, John P., Hegi, Lukas, Bassler, Dirk, Arlettaz, Romaine, Bernet, Vera, Dani, Carlo, Fiorini, Patrizio, Ghirri, Paolo, Tomasini, Barbara, Mittal, Anita, Kefas, Jonathan, Kamalanathan, Anand, Grosdenier, Michael, Dewhurst, Christopher, Bontea, Andreea, Webb, Delyth, Garr, Ross, Hassan, Ahmed, Ambadkar, Priyadarshan, Dyke, Mark, McDevitt, Katharine, Rewitzky, Glynis, D'Amore, Angela, Kamath, P., Settle, Paul, Maddock, Natasha, Edi-Osagie, Ngozi, Zipitis, Christos, Heal, Carrie, Birch, Jacqeline, Hasib, Abdul, Soe, Aung, Abdul-Malik, Bushra, Kisat, Hamudi, Vasu, Vimal, Sivashankar, Savi, Gupta, Richa, Rawlingson, Chris, Wickham, Tim, Theron, Marice, Kendall, Giles, Gupta, Aashish, Aladangady, Narendra, Ali, Imdad, Jain, Neeraj, Mannan, Khalid, Murthy, Vadivelam, Sullivan, Caroline, Chuang, Shu-Ling, Bate, Tristan, Tyszcuzk, Lidia, Lee, Geraint, Obi, Ozioma, Chang, John, Pai, Vinay, Huddy, Charlotte, Yasin, Salim, Nicholl, Richard, Pandey, Poornima, Cusack, Jonathan, Kairamkonda, Venkatesh, Muogbo, Dominic, Harry, Liza, Surana, Pinki, Broggio, Penny, Pillay, Tilly, Deshpande, Sanjeev, Mahadevan, Moore, Alison, Bastani, Porus, Garbash, Mehdi, Lal, Mithilesh, Abu-Harb, Majd, Allwood, Alex, Selter, Michael, Munyard, Paul, Bartle, David, Paul, Siba, Whincup, Graham, Rekha, Sanghavi, Amess, Philip, Obi, Ben, Reynolds, Peter, Misra, Indranil, De Halpert, Peter, Salgia, Sanjay, Sanghavi, Rekha, Paul, Nicola, Deketelaere, Abby, Khashu, Minesh, Johnson, Mark, Groves, Charlotte, Baird, Jim, Brennan, Nick, Vamvakiti, Katia, McIntyre, John, Holman, Jennifer, Jones, Stephen, Pike, Alison, Cairns, Pamela, Eaton, Megan, Schwarz, Karin, Gibson, David, Miall, Lawrence, Krishnamurthy, Dr, Narayanan, Sankara, Seaton, Sarah E., Draper, Elizabeth S., Kusuda, Satoshi, Håkansson, Stellan, Helenius, Kjell, Reichman, Brian, Vento, Maximo, Darlow, Brian A., Rusconi, Franca, Isayama, Tetsuya, Norman, Mikael, Yang, Junmin, and Modi, Neena

Published
2021
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46. Nematicidal and Insecticidal Compounds from the Laurel Forest Endophytic Fungus Phyllosticta sp.

Author

Díaz, Carmen E., Andrés, María Fe, Bolaños, Patricia, and González-Coloma, Azucena

Subjects
*SPODOPTERA littoralis, *RHOPALOSIPHUM padi, *GREEN peach aphid, *AVOCADO, *JAVANESE root-knot nematode, *NEMATOCIDES, *ENDOPHYTIC fungi, *BIOPESTICIDES
Abstract

The search for natural product-based biopesticides from endophytic fungi is an effective tool to find new solutions. In this study, we studied a pre-selected fungal endophyte, isolate YCC4, from the paleoendemism Persea indica, along with compounds present in the extract and the identification of the insect antifeedant and nematicidal ones. The endophyte YCC4 was identified as Phyllosticta sp. by molecular analysis. The insect antifeedant activity was tested by choice bioassays against Spodoptera littoralis, Myzus persicae, and Rhopalosiphum padi, and the in vitro and in vivo mortality was tested against the root-knot nematode Meloidogyne javanica. Since the extract was an effective insect antifeedant, a strong nematicidal, and lacked phytotoxicity on tomato plants, a comprehensive chemical study was carried out. Two new metabolites, metguignardic acid (4) and (-)-epi-guignardone I (14), were identified along the known dioxolanones guignardic acid (1), ethyl guignardate (3), guignardianones A (5), C (2), D (7), and E (6), phenguignardic acid methyl ester (8), the meroterpenes guignardone A (9) and B (10), guignarenone B (11) and C (12), (-)-guignardone I (13), and phyllomeroterpenoid B (15). Among these compounds, 1 and 4 were effective antifeedants against S. littoralis and M. persicae, while 2 was only active on the aphid M. persicae. The nematicidal compounds were 4, 7, and 8. This is the first report on the insect antifeedant or nematicidal effects of these dioxolanone-type compounds. Since the insect antifeedant and nematicidal activity of the Phyllosticta sp. extract depend on the presence of dioxolanone components, future fermentation optimizations are needed to promote the biosynthesis of these compounds instead of meroterpenes. [ABSTRACT FROM AUTHOR]

Published
2024
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47. Inhibition of mTOR prevents glucotoxicity-mediated increase of SA-beta-gal, p16INK4a, and insulin hypersecretion, without restoring electrical features of mouse pancreatic islets.

Author

Guzmán, Tereso J., Klöpper, Nina, Gurrola-Díaz, Carmen M., and Düfer, Martina

Abstract

An over-activation of the mechanistic target of rapamycin (mTOR) pathway promotes senescence and age-related diseases like type 2 diabetes. Besides, the regenerative potential of pancreatic islets deteriorates with aging. Nevertheless, the role of mTOR on senescence promoted by metabolic stress in islet cells as well as its relevance for electrophysiological aspects is not yet known. Here, we investigated whether parameters suggested to be indicative for senescence are induced in vitro in mouse islet cells by glucotoxicity and if mTOR inhibition plays a protective role against this. Islet cells exhibit a significant increase (~ 76%) in senescence-associated beta-galactosidase (SA-beta-gal) activity after exposure to glucotoxicity for 72 h. Glucotoxicity does not markedly influence p16INK4a protein within 72 h, but p16INK4a levels increase significantly after a 7-days incubation period. mTOR inhibition with a low rapamycin concentration (1 nM) entirely prevents the glucotoxicity-mediated increase of SA-beta-gal and p16INK4a. At the functional level, reactive oxygen species, calcium homeostasis, and electrical activity are disturbed by glucotoxicity, and rapamycin fails to prevent this. In contrast, rapamycin significantly attenuates the insulin hypersecretion promoted by glucotoxicity by modifying the mRNA levels of Vamp2 and Snap25 genes, related to insulin exocytosis. Our data indicate an influence of glucotoxicity on pancreatic islet-cell senescence and a reduction of the senescence markers by mTOR inhibition, which is relevant to preserve the regenerative potential of the islets. Decreasing the influence of mTOR on islet cells exposed to glucotoxicity attenuates insulin hypersecretion, but is not sufficient to prevent electrophysiological disturbances, indicating the involvement of mTOR-independent mechanisms. [ABSTRACT FROM AUTHOR]

Published
2024
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