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4. Permeation mechanisms of hydrogen peroxide and water through Plasma Membrane Intrinsic Protein aquaporins.

Author

Chevriau, Jonathan, De Palma, Gerardo Zerbetto, Jozefkowicz, Cintia, Vitali, Victoria, Fortuna, Agustina Canessa, Ayub, Nicolas, Soto, Gabriela, Bienert, Gerd Patrick, Zeida, Ari, and Alleva, Karina

Subjects
MEMBRANE proteins, CELL membranes, MOLECULAR dynamics, HYDROGEN peroxide, AQUAPORINS
Abstract

Hydrogen peroxide (H2O2) transport by aquaporins (AQP) is a critical feature for cellular redox signaling. However, the H2O2 permeation mechanism through these channels remains poorly understood. Through functional assays, two Plasma membrane Intrinsic Protein (PIP) AQP from Medicago truncatula, MtPIP2;2 and MtPIP2;3 have been identified as pH-gated channels capable of facilitating the permeation of both water (H2O) and H2O2. Employing a combination of unbiased and enhanced sampling molecular dynamics simulations, we investigated the key barriers and translocation mechanisms governing H2O2 permeation through these AQP in both open and closed conformational states. Our findings reveal that both H2O and H2O2 encounter their primary permeation barrier within the selectivity filter (SF) region of MtPIP2;3. In addition to the SF barrier, a second energetic barrier at the NPA (asparagine-proline-alanine) region that is more restrictive for the passage of H2O2 than for H2O, was found. This behavior can be attributed to a dissimilar geometric arrangement and hydrogen bonding profile between both molecules in this area. Collectively, these findings suggest mechanistic heterogeneity in H2O and H2O2 permeation through PIPs. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Building momentum through networks: Bioimaging across the Americas

Author

De Niz, Mariana, primary, Escobedo García, Rodrigo, additional, Terán Ramirez, Celina, additional, Pakowski, Ysa, additional, Abonza, Yuriney, additional, Bialy, Nikki, additional, Orr, Vanessa L., additional, Olivera, Andres, additional, Abonza, Victor, additional, Alleva, Karina, additional, Allodi, Silvana, additional, Almeida, Michael F., additional, Becerril Cuevas, Alexis Ricardo, additional, Bonnet, Frederic, additional, Burgos Solorio, Armando, additional, Chew, Teng‐Leong, additional, Chiabrando, Gustavo, additional, Cimini, Beth, additional, Cleret‐Buhot, Aurélie, additional, Contreras Jiménez, Gastón, additional, Daza, Laura, additional, De Sá, Vanessa, additional, De Val, Natalia, additional, Delgado‐Álvarez, Diego L., additional, Eliceiri, Kevin, additional, Fiolka, Reto, additional, Grecco, Hernan, additional, Hanein, Dorit, additional, Hernández Herrera, Paúl, additional, Hockberger, Phil, additional, Hernandez, Haydee O., additional, Hernandez Guadarrama, Yael, additional, Itano, Michelle, additional, Jacobs, Caron A., additional, Jiménez‐García, Luis F., additional, Jiménez Sabinina, Vilma, additional, Kamaid, Andres, additional, Keppler, Antje, additional, Kumar, Abhishek, additional, Lacoste, Judith, additional, Lovy, Alenka, additional, Luby‐Phelps, Kate, additional, Mahadevan‐Jansen, Anita, additional, Malacrida, Leonel, additional, Mehta, Shalin B., additional, Miller, Caroline, additional, Miranda, Kildare, additional, Moore, Joshua A., additional, North, Alison, additional, O'Toole, Peter, additional, Olivares Urbano, Mariana, additional, Pietrasanta, Lía I., additional, Portugal, Rodrigo V., additional, Rossi, Andrés H., additional, Sanchez Contreras, Jonathan, additional, Strambio‐De‐Castilla, Caterina, additional, Soldevila, Gloria, additional, Vale, Bruno, additional, Vazquez, Diana, additional, Wood, Chris, additional, Brown, Claire M., additional, and Guerrero, Adan, additional

Published
2024
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16. The plasma membrane aquaporin ZmPIP1;1 interacts with ZmPIP2s to increase the water membrane permeability of maize cells

Author

UCL - SST/LIBST - Louvain Institute of Biomolecular Science and Technology, UCL - Faculté des Sciences, Chaumont, François, Ghislain, Michel, Morsomme, Pierre, Bienert, Gerd Patrick, Alleva, Karina, Teodoro Junqueira, Bruna Rayane, UCL - SST/LIBST - Louvain Institute of Biomolecular Science and Technology, UCL - Faculté des Sciences, Chaumont, François, Ghislain, Michel, Morsomme, Pierre, Bienert, Gerd Patrick, Alleva, Karina, and Teodoro Junqueira, Bruna Rayane

Abstract

Aquaporins (AQPs) are channels present in all living organisms. They share the hour-glass shape and are involved in many cellular processes. Plasma membrane intrinsic proteins (PIPs) are AQPs responsible for the facilitated diffusion of water and small solutes through plasma membrane (PM). Land plant PIP subfamily is composed of two distinguishable phylogenetic clusters: PIP1 and PIP2. They assemble as homo- or heterotetramers, the monomer being the functional unit. Previous works have demonstrated that PIPs present a dissimilar behavior regarding their subcellular localization and function. PIP2s are considered as efficient water channels and they localize in the PM. On the other hand, when expressed alone, most of the PIP1s are retained in the endoplasmic reticulum (ER) and are not efficient water channels. When co-expressed, PIP1s and PIP2s interact, a process leading to the relocalization of PIP1s from the ER to the PM and to an increase in the cell water permeability. In maize, this synergistic effect was observed for most of ZmPIP1s members, including ZmPIP1;2 when co-expressed with ZmPIP2;5. This unexpected synergy together with localization studies led researchers to further investigate the nature of ZmPIP1 and ZmPIP2 interaction. The heterotetramerization of PIP monomers is the mechanism responsible for the ZmPIP1 trafficking to the PM and for the modulation of the cell membrane permeability. ZmPIP1;1 is a ubiquitous and one of the highest expressed AQP in maize. It is the closest paralog of ZmPIP1;2. Despite their striking similarity, their function does not correlate. Previous studies showed that the co-expression of ZmPIP1;1 with ZmPIP2;5 did not lead to a synergistic effect in oocyte membrane water permeability, while both isoforms were physically interacting and found in the PM. This enigmatic isoform has been considered to be an inactive water channel until nowadays. In this thesis, we aimed at unraveling the role of ZmPIP1;1, using heterologous and h, (SC - Sciences) -- UCL, 2022

Published
2022

26. Plasma membrane aquaporins interact with the endoplasmic reticulum resident VAP27 proteins at ER–PM contact sites and endocytic structures

Author

UCL - SST/LIBST - Louvain Institute of Biomolecular Science and Technology, Fox, Ana Romina, Scochera, Florencia, Laloux, Timothée, Filik, Karolina, Degand, Hervé, Morsomme, Pierre, Alleva, Karina, Chaumont, François, UCL - SST/LIBST - Louvain Institute of Biomolecular Science and Technology, Fox, Ana Romina, Scochera, Florencia, Laloux, Timothée, Filik, Karolina, Degand, Hervé, Morsomme, Pierre, Alleva, Karina, and Chaumont, François

Abstract

Plasma membrane (PM) intrinsic proteins (PIPs) are aquaporins facilitating the diffusion of water and small solutes. The functional importance of the PM organisation of PIPs in the interaction with other cellular structures is not completely understood. We performed a pull-down assay using maize (Zea mays) suspension cells expressing YFP-ZmPIP2;5 and validated the protein interactions by yeast split-ubiquitin and bimolecular fluorescence complementation assays. We expressed interacting proteins tagged with fluorescent proteins in Nicotiana benthamiana leaves and performed water transport assays in oocytes. Finally, a phylogenetic analysis was conducted. The PM-located ZmPIP2;5 physically interacts with the endoplasmic reticulum (ER) resident ZmVAP27-1. This interaction requires the ZmVAP27-1 cytoplasmic major sperm domain. ZmPIP2;5 and ZmVAP27-1 localise in close vicinity in ER–PM contact sites (EPCSs) and endocytic structures upon exposure to salt stress conditions. This interaction enhances PM water permeability in oocytes. Similarly, the Arabidopsis ZmVAP27-1 paralogue, AtVAP27-1, interacts with the AtPIP2;7 aquaporin. Together, these data indicate that the PIP2–VAP27 interaction in EPCSs is evolutionarily conserved, and suggest that VAP27 might stabilise the aquaporins and guide their endocytosis in response to salt stress.

Published
2020

29. PIP aquaporin pH‐sensing is regulated by the length and charge of the C‐terminal region.

Author

Scochera, Florencia, Zerbetto De Palma, Gerardo, Canessa Fortuna, Agustina, Chevriau, Jonathan, Toriano, Roxana, Soto, Gabriela, Zeida, Ari, and Alleva, Karina

Subjects
AQUAPORINS, MOLECULAR dynamics, BEETS, PLANT-water relationships, STRUCTURAL models
Abstract

Plant PIP aquaporins play a central role in controlling plant water status. The current structural model for PIP pH‐gating states that the main pH sensor is located in loopD and that all the mobile cytosolic elements participate in a complex interaction network that ensures the closed structure. However, the precise participation of the last part of the C‐terminal domain (CT) in PIP pH gating remains unknown. This last part has not been resolved in PIP crystal structures and is a key difference between PIP1 and PIP2 paralogues. Here, by a combined experimental and computational approach, we provide data about the role of CT in pH gating of Beta vulgaris PIP. We demonstrate that the length of CT and the positive charge located among its last residues modulate the pH at which the open/closed transition occurs. We also postulate a molecular‐based mechanism for the differential pH sensing in PIP homo‐ or heterotetramers by performing atomistic molecular dynamics simulations (MDS) on complete models of PIP tetramers. Our findings show that the last part of CT can affect the environment of loopD pH sensors in the closed state. Results presented herein contribute to the understanding of how the characteristics of CT in PIP channels play a crucial role in determining the pH at which water transport through these channels is blocked, highlighting the relevance of the differentially conserved very last residues in PIP1 and PIP2 paralogues. [ABSTRACT FROM AUTHOR]

Published
2022
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32. Efectos de la hipercompetitividad en el área de las biociencias : crisis del sistema postdoctoral

Author

Alleva, Karina and Centro de Estudios sobre Ingeniería y Sociedad. Facultad de Ingeniería y Ciencias Agrarias. Universidad Católica Argentina

Subjects
INVESTIGADORES, INVESTIGACION CIENTIFICA, SECTOR PUBLICO, SECTOR PRIVADO, POLITICA PUBLICA, BIOCIENCIAS
Abstract

Fil: Alleva, Karina. Universidad de Buenos Aires; Argentina Fil: Alleva, Karina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Dentro del espectro de disciplinas científicas, las áreas del sistema actual de Investigación y Desarrollo (I+D) que se dedican a estudios biológicos y biomédicos, también llamadas biociencias, han logrado importantes progresos en las últimas décadas. En este sentido se plantea que, particularmente en países desarrollados, estas disciplinas estarían atravesando lo que algunos autores denominan una “época dorada” (Alberts et al., 2014). Sin embargo, desde hace algunos años se empieza a reconocer que el sistema actual tiene algunas deficiencias que pueden pensarse como sistémicas y que, sin duda ameritan atención. Uno de los problemas más acuciantes es el retraso en la inserción de jóvenes investigadores con puestos estables al sistema científico. Para comprender esta situación es necesario analizar algunas de las particularidades del área de las biociencias. El área de las biociencias es un sector de alta dependencia de fondos (sean públicos o privados), ya que debido a su carácter netamente experimental requiere insumos y equipamientos en forma constante. El crecimiento exponencial que el área ha venido sosteniendo en las últimas décadas, sumado a esta alta dependencia de fondos, desembocó en una situación que algunos autores denominan como de hipercompetitividad...

Published
2017

34. Heteromerization of Plant Aquaporins

Author

UCL - SST/ISV - Institut des sciences de la vie, Jozefkowicz, Cintia, Berny, Marie, Chaumont, François, Alleva, Karina, UCL - SST/ISV - Institut des sciences de la vie, Jozefkowicz, Cintia, Berny, Marie, Chaumont, François, and Alleva, Karina

Abstract

Aquaporins are channel proteins that facilitate the diffusion of water and small uncharged solutes across cellular membranes. Plant aquaporins form a large family of highly divergent proteins that are involved in many different physiological processes. This book will summarize the recent advances regarding plant aquaporins, their phylogeny, structure, substrate specificity, mechanisms of regulation and roles in various important physiological processes related to the control of water flow and small solute distribution at the cell, tissue and plant level in an ever-changing environment.

Published
2017

35. Major cereal crops benefit from biological nitrogen fixation when inoculated with the nitrogen-fixing bacterium Pseudomonas protegens Pf-5 X940

Author

Fox, Ana Romina, Soto, Gabriela Cinthia, Valverde, Claudio Fabián, Russo, Daniela Marta, Lagares, Antonio, Zorreguieta, Ángeles, Pascuan, Cecilia Gabriela, Frare, Romina Alejandra, Mercado Blanco, Jesús, Dixon, Ray, Ayub, Nicolás Daniel, and Alleva, Karina Edith

Subjects
Nitrogen, Bacteria Fijadora del Nitrógeno, Biological Nitrogen Fixation, Bioquímica y Biología Molecular, Maize, Fijación Biológica del Nitrógeno, Ciencias Biológicas, purl.org/becyt/ford/1 [https], Cultivos de Cereales, Pseudomonas, Wheat, purl.org/becyt/ford/1.6 [https], Nitrogen Fixing Bacteria, CIENCIAS NATURALES Y EXACTAS, Cereal Crops
Abstract

A main goal of biological nitrogen fixation (BNF) research has been to expand the nitrogenfixing ability to major cereal crops. In this work, we demonstrate the use of the efficient nitrogen-fixing rhizobacterium Pseudomonas protegens Pf-5 X940 as a chassis to engineer the transfer of nitrogen fixed by BNF to maize and wheat under non-gnotobiotic conditions. Inoculation of maize and wheat with Pf-5 X940 largely improved nitrogen content and biomass accumulation in both vegetative and reproductive tissues, and this beneficial effect was positively associated with high nitrogen fixation rates in roots. 15N isotope dilution analysis showed that maize and wheat plants obtained substantial amounts of fixed nitrogen from the atmosphere. Pf-5 X940-GFP-tagged cells were always reisolated from the maize and wheat root surface but never from the inner root tissues. Confocal laser scanning microscopy confirmed root surface colonization of Pf-5 X940-GFP in wheat plants, and microcolonies were mostly visualized at the junctions between epidermal root cells. Genetic analysis using biofilm formation-related Pseudomonas mutants confirmed the relevance of bacterial root adhesion in the increase in nitrogen content, biomass accumulation and nitrogen fixation rates in wheat roots. To our knowledge, this is the first report of robust BNF in major cereal crops. Fil: Fox, Ana Romina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Soto, Gabriela Cynthia. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Valverde, Claudio Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina Fil: Russo, Daniela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina Fil: Lagares, Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina Fil: Zorreguieta, Ángeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina Fil: Alleva, Karina Edith. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Físico Matemática; Argentina Fil: Pascuan, Cecilia Gabriela. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Frare, Romina Alejandra. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Mercado Blanco, Jesús. Consejo Superior de Investigaciones Cientificas; España Fil: Dixon, Ray. John Innes Institute; Reino Unido Fil: Ayub, Nicolás Daniel. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Published
2016

38. Lecciones aprendidas sobre cómo promover cambios genuinos en grandes equipos docentes

Author

Alleva, Karina

Subjects
Innovación educativa, Educación, Ciencias Médicas, Comunidad de práctica, Alosterismo
Abstract

En los últimos años aparece como recurrente en el ámbito de la enseñanza universitaria, la necesidad de incorporar TIC (tecnologías de la información y la comunicación) a las prácticas docentes. Mucho se ha reflexionado sobre la necesidad de llevar adelante esta innovación yendo más allá del mero uso de herramientas tecnológicas en clase. Sabemos que lo que guía las buenas innovaciones no es la inclusión de tecnologías novedosas en el aula, sino un pensamiento pedagógico-didáctico y de comunidad que configura el ingreso de tecnologías en pos de mejoras en los procesos de enseñanza y aprendizaje. Sin embargo, innovar dentro de las universidades suele no ser simple, por lo que abordar proyectos innovadores en estructuras educativas de este tipo siempre es un reto que requiere además de voluntad, gran capacidad para el trabajo colaborativo. En esta presentación tomamos la idea de transición alostérica desarrollada por Monod en los años ´60 en el ámbito de la bioquímica como herramienta heurística para visualizar una propuesta de cómo puede abordarse el trabajo dentro de los equipos docentes cuando se busca promover cambios genuinos en las prácticas., Sociedad Argentina de Fisiología

Published
2014

39. Cooperativity in proton sensing by PIP aquaporins.

Author

Vitali, Victoria, Jozefkowicz, Cintia, Canessa Fortuna, Agustina, Soto, Gabriela, González Flecha, F. Luis, and Alleva, Karina

Subjects
AQUAPORINS, CELL membranes, STOICHIOMETRY, AMINO acids, PROTONS
Abstract

One of the most intriguing properties of plasma membrane intrinsic protein (PIP) aquaporins (AQPs) is their ability to modulate water transport by sensing different levels of intracellular pH through the assembly of homo‐ and heterotetrameric molecular species in the plasma membrane. In this work, using a phenomenological modeling approach, we demonstrate that cooperativity in PIP biological response cannot be directly attributed to a cooperative proton binding, as it is usually considered, since it could also be the consequence of a cooperative conformation transition between open and closed states of the channel. Moreover, our results show that, when mixed populations of homo‐ and heterotetrameric PIP channels are coexpressed in the plasma membrane of the same cell, the observed decrease in the degree of positive cooperativity would result from the simultaneous presence of molecular species with different levels of proton sensing. Indeed, the random mixing between different PIP paralogues as subunits in a single tetramer, plus the possibility of mixed populations of homo‐ and heterotetrameric PIP channels widen the spectrum of cooperative responses of a cell membrane. Our approach offers a deep understanding of cooperative transport of AQP channels, as members of a multiprotein family where the relevant proton binding sites of each member have not been clearly elucidated yet. One of the most amazing properties of PIP aquaporins is their ability to cooperatively modulate water transport. We used a phenomenological modeling approach to show that this cooperativity can be attributed not only to the binding of protons but also to the conformational transition. We also uncover that mixed populations of homo‐ and heterotetrameric PIP channels in a cell membrane allow a wide spectrum of cooperative responses improving the effective water transport of that cell. [ABSTRACT FROM AUTHOR]

Published
2019
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40. Major cereal crops benefit from biological nitrogen fixation when inoculated with the nitrogen-fixing bacteriumPseudomonas protegensPf-5 X940

Author

UCL - SST/ISV - Institut des sciences de la vie, Fox, Ana Romina, Soto, Gabriela, Valverde, Claudio, Russo, Daniela, Lagares, Antonio, Zorreguieta, Ángeles, Alleva, Karina, Pascuan, Cecilia, Frare, Romina, Mercado-Blanco, Jesús, Dixon, Ray, Ayub, Nicolás Daniel, UCL - SST/ISV - Institut des sciences de la vie, Fox, Ana Romina, Soto, Gabriela, Valverde, Claudio, Russo, Daniela, Lagares, Antonio, Zorreguieta, Ángeles, Alleva, Karina, Pascuan, Cecilia, Frare, Romina, Mercado-Blanco, Jesús, Dixon, Ray, and Ayub, Nicolás Daniel

Abstract

A main goal of biological nitrogen fixation research has been to expand the nitrogen-fixing ability to major cereal crops. In this work, we demonstrate the use of the efficient nitrogen-fixing rhizobacterium Pseudomonas protegens Pf-5 X940 as a chassis to engineer the transfer of nitrogen fixed by BNF to maize and wheat under non-gnotobiotic conditions. Inoculation of maize and wheat with Pf-5 X940 largely improved nitrogen content and biomass accumulation in both vegetative and reproductive tissues, and this beneficial effect was positively associated with high nitrogen fixation rates in roots. 15N isotope dilution analysis showed that maize and wheat plants obtained substantial amounts of fixed nitrogen from the atmosphere. Pf-5 X940-GFP-tagged cells were always reisolated from the maize and wheat root surface but never from the inner root tissues. Confocal laser scanning microscopy confirmed root surface colonization of Pf-5 X940-GFP in wheat plants, and microcolonies were mostly visualized at the junctions between epidermal root cells. Genetic analysis using biofilm formation-related Pseudomonas mutants confirmed the relevance of bacterial root adhesion in the increase in nitrogen content, biomass accumulation and nitrogen fixation rates in wheat roots. To our knowledge, this is the first report of robust BNF in major cereal crops.

Published
2016

41. Aquaporin Trafficking as a Specific Regulatory Mechanism to Adjust Membrane Water Permeability

Author

Scochera Florencia, Marquez Mercedes, Alleva Karina, Jozefkowicz Cintia, Vitali Victoria, Gabriela Amodeo, and Yaneff Agustin

Subjects
Water transport, biology, urogenital system, Mutant, Xenopus, Biophysics, Aquaporin, Gating, Permeation, biology.organism_classification, Cytosol, Membrane, Biochemistry, lipids (amino acids, peptides, and proteins)
Abstract

Plant aquaporins regulate water fluxes across membranes by enhancing membrane water permeability (Pf). In particular, the plant plasma membrane holds PIPs, one of the largest groups of aquaporins. PIPs are divided in two clusters (PIP1 and PIP2) that disclose intriguing aspects: i) the potential of modulating Pf by PIP1-PIP2 co-expression, distinguished for each PIP showing differential capacity to reach the PM and ii), the faculty to reduce water permeation through the pore after cytosolic acidification, as a consequence of a gating process. Our working hypothesis is that cytosolic pH (gating) and PIP co-expression (trafficking) enhance plasticity to the membrane water transport capacity as a consequence of a PIP1-PIP2 cooperative interaction. Thus, PIP1 cellular trafficking and its effect in water permeability emerge as playing a key role as a regulatory mechanism. To analyze this interaction we used PIP1-PIP2 pairs from different species (Fragaria ananassa and Beta vulgaris). Our experimental approach included i) designing mutants to alter the PIP-PIP2 interaction by means of site directed mutagenesis; ii) tracking aquaporin localization -at internal structures or expressed at the level of the PM-; and iii) analyzing water transport capacity in control and inhibited (medium acidification) conditions by means of measuring Pf in Xenopus oocytes. Our finding support evidences in agreement with the concept that PIP2 and PIP1 interact to form functional heterooligomeric assemblies, and thus the composition of these PIP assemblies determines their functional properties. As PIP1 alone is not able to reach the plasma membrane its contribution to enhance water permeability is associated to its translocation and interaction with a PIP2. This regulatory mechanism seems to be present in different vascular plants. This information is integrated in a proposal for water transport pathways including the organs where this PIPs are present.

Published
2014
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44. Major cereal crops benefit from biological nitrogen fixation when inoculated with the nitrogen-fixing bacterium Pseudomonas protegens Pf-5 X940

Author

Fox, Ana Romina, primary, Soto, Gabriela, additional, Valverde, Claudio, additional, Russo, Daniela, additional, Lagares, Antonio, additional, Zorreguieta, Ángeles, additional, Alleva, Karina, additional, Pascuan, Cecilia, additional, Frare, Romina, additional, Mercado-Blanco, Jesús, additional, Dixon, Ray, additional, and Ayub, Nicolás Daniel, additional

Published
2016
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46. Could an understanding of the strawberry softening process benefit from Aquaporins

Author

Alleva, Karina Edith, Marquez, Mercedes, Bellati, Jorge, Villarreal, Natalia Marina, Bustamante, Claudia Anabel, Martinez, Gustavo Adolfo, Civello, Marcos, and Amodeo, Gabriela

Subjects
purl.org/becyt/ford/1 [https], Ciencias Biológicas, Turgor, Ripening, Water channel, Bioquímica y Biología Molecular, purl.org/becyt/ford/1.6 [https], CIENCIAS NATURALES Y EXACTAS, Fragaria x ananassa
Abstract

Strawberry is the most economically important soft fruit characterized by its delicious flavour, intense colour and soft texture. The rapid loss of firmness during strawberry ripening is the main determining factor of its short shelf life, and great losses occur by bruising, oversoftening and subsequent fungal infections during postharvest transportation and storage. Cell wall disassembly and the reduction of cell to cell adhesion due to middle lamella dissolution have been recognized as the main causes of fruit softening. In the case of strawberry fruit, cell wall disassembly during ripening is characterized by a solubilization of pectins, a slight depolymerization of covalently bound pectins, a loss of galactose and arabinose, as well as a reduction in the hemicellulosic content. The genetic manipulation of genes encoding proteins involved in wall disassembly has been explored as a biotechnological approach to reduce fruit softening. Thus, the silencing of fruit specific pectate lyase or polygalacturonase genes, both acting on demethylated pectins, by antisense transformation increased significantly the firmness of ripe strawberry fruit without affecting other fruit quality parameters. By contrast, the down-regulation of the expression of genes involved in the processing of hemicellulosic polymers, such as endo-b-1,4-glucanase or expansin genes, did not modify fruit firmness. Other cell wall genes, e.g. b-xylosidase, b-galactosidase, α-arabinofuranosidase, have been cloned in strawberry fruit, and their expression analyzed along fruit development, but their function on fruit softening has not been assessed yet by transgenic approaches. Overall, these results indicate that pectin processing during ripening is a critical factor in the softening of strawberry fruit, and the manipulation of this process by down-regulating pectinase genes a successful approach to improve this trait. This review summarizes recent progress on strawberry fruit softening, focusing in the role of cell wall disassembly and genes involved in that process. Fil: Alleva, Karina Edith. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Marquez, Mercedes. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina Fil: Bellati, Jorge. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Villarreal, Natalia Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús. Instituto de Investigaciones Biotecnológicas (sede Chascomús); Argentina. Universidad Nacional de San Martín; Argentina Fil: Bustamante, Claudia Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús. Instituto de Investigaciones Biotecnológicas (sede Chascomús); Argentina. Universidad Nacional de San Martín; Argentina Fil: Martinez, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús. Instituto de Investigaciones Biotecnológicas (sede Chascomús); Argentina. Universidad Nacional de San Martín; Argentina Fil: Civello, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús. Instituto de Investigaciones Biotecnológicas (sede Chascomús); Argentina. Universidad Nacional de San Martín; Argentina Fil: Amodeo, Gabriela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Published
2011

47. Could the understanding of the strawberry softening process benefit from aquaporins?

Author

Alleva, Karina Edith, Marquez, Mercedes, Bellati, Jorge, Villareal, Natalia, Bustamante, Claudia Anabel, Martinez, Gustavo Adolfo, Civello, Pedro Marcos, and Amodeo, Gabriela

Subjects
Ciencias Biológicas, TURGOR, purl.org/becyt/ford/1 [https], RIPENING, Otras Ciencias Biológicas, FRAGARIA X ANANASSA, purl.org/becyt/ford/1.6 [https], CIENCIAS NATURALES Y EXACTAS, WATER CHANNEL
Abstract

The Major Intrinsic Protein (MIP) family includes a main group of key channels known as aquaporins (AQPs), described for sharing a very conservative structure with a pore that facilitates water and/or solute permeation. Since its first member was functionally reported in 1992, AQPs were found to be abundantly expressed in all kingdoms. Although many roles have been attributed to these small integral proteins, it is becoming evident that the number and type of AQPs within a membrane are major determinants of its water transport capacity. Thus, their presence is opening new perspectives to understand the role of plant cell membrane water transport in physiological and developmental processes. Strawberry is a fleshy fruit characterized by a rapid loss of firmness during ripening, limiting the shelf-life of these fruit. Even though fruit texture is influenced by various factors like structural integrity of primary cell wall, sugar accumulation, and the turgor pressure generated within cells by osmosis, main attention has been focused on degradation of cell wall polysaccharides. Turgor pressure, in spite of long being mentioned as a possible player in softening during fruit development, has not received proper consideration. In the light of AQP outbreak, it is worth questioning how these channels could contribute to strawberry fruit softening. In an attempt to answer this question, this review summarizes the current available information on plant AQPs, extending the knowledge to those specifically expressed in fruits to finally discuss the recent reported findings in strawberry, particularly those associated with ripening and softening processes. Fil: Alleva, Karina Edith. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Marquez, Mercedes. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina Fil: Bellati, Jorge. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Villareal, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "dr. Raul Alfonsin" (sede Chascomus) | Universidad Nacional de San Martin. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; Argentina Fil: Bustamante, Claudia Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "dr. Raul Alfonsin" (sede Chascomus) | Universidad Nacional de San Martin. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; Argentina Fil: Martinez, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "dr. Raul Alfonsin" (sede Chascomus) | Universidad Nacional de San Martin. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; Argentina Fil: Civello, Pedro Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "dr. Raul Alfonsin" (sede Chascomus) | Universidad Nacional de San Martin. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; Argentina Fil: Amodeo, Gabriela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Published
2011

48. TIP5;1 is an aquaporin specifically targeted to pollen mitochondria and is probably involved in nitrogen remobilization in Arabidopsis thaliana

Author

Soto, Gabriela Cynthia, Fox, Ana Romina, Ayub, Nicolas Daniel, Alleva, Karina Edith, Guaimas, Francisco Fernando, Jares, Elizabeth Andrea, Mazzella, Maria Agustina, Amodeo, Gabriela, and Muschietti, Jorge Prometeo

Subjects
Arabidopsis thaliana, Nitrogen, AQUAPORINS, Otras Ciencias Biológicas, PH SENSING, water, Arabidopsis, Pollen Tube, Plant sexual reproduction, phylogeny, Remobilization, Ciencias Biológicas, purl.org/becyt/ford/1 [https], In-vitro, MITOCHONDRIA, mitochondrion, TIP5, 1 protein, Arabidopsis, genetics, purl.org/becyt/ford/1.6 [https], Solute movement, Water transport, Glycoproteins, Single mutant, plant RNA, Arabidopsis protein, pH, Arabidopsis Proteins, article, gene expression regulation, Hydrogen-Ion Concentration, aquaporin, NITROGEN METABOLISM, Mutagenesis, Insertional, Metabolism, RNA, Plant, pH sensors, Amino acids, Double mutants, Xenopus oocyte, UREA, CIENCIAS NATURALES Y EXACTAS
Abstract

In plant sexual reproduction, water and solute movement are tightly regulated, suggesting the involvement of aquaporins. We previously identified TIP5;1 and TIP1;3 as the only Arabidopsis aquaporin genes that are selectively and highly expressed in mature pollen, and showed that they can transport both water and urea when expressed in Xenopus oocytes. Here, we show that TIP5;1 has unusual characteristics, as its water transport activity is regulated by pH. Analysis of the water transport activity of a mutant version of TIP5;1 (TIP5;1-H131A) and amino acid alignment with other plant aquaporins regulated by pH suggested that a conserved motif is involved in pH sensing. GFP–TIP5;1 is located in the mitochondria of pollen tubes. The single mutants tip1;3 and tip5;1, as well as the tip1;3 tip5;1 double mutant, are fertile, but all mutants had shorter than normal pollen tubes when germinated in vitro in the absence of exogenous nitrogen. Thus, we propose that TIP5;1 and TIP1;3 are involved in nitrogen recycling in pollen tubes of Arabidopsis thaliana. Fil: Soto, Gabriela Cynthia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina Fil: Fox, Ana Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina Fil: Ayub, Nicolas Daniel. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación En Ciencias Veterinarias y Agronomicas. Instituto de Genetica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Alleva, Karina Edith. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Guaimas, Francisco Fernando. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Jares, Elizabeth Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Mazzella, Maria Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina Fil: Amodeo, Gabriela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Muschietti, Jorge Prometeo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina

Published
2010

50. Arabidopsis pollen TIPs involved in pollen tube elongation

Author

Soto, Gabriela, Fox, Ana Romina, Alleva, Karina, Mazzella, Agustina, Amodeo, Gabriela, Muschietti, Jorge P, XLV Annual Meeting Argentine Society for Biochemistry and Molecular Biology, and UCL - SST/ISV - Institut des sciences de la vie

Subjects
food and beverages
Abstract

Reproduction in flowering plants includes processes, like pollen germination and pollen tube elongation, where water and/ or solutes movements must be finely regulated. These regulations suggest the participation of aquaporins mediating water and solutes transport. AtTIP5;1 and AtTIP1;3 are the only aquaporins that are selectively and highly expressed in Arabidopsis thaliana mature pollen. In a heterologous system (Xenopus oocytes), both TIPs showed urea and water transport but neither glycerol nor boric acid (Soto, FEBS Lett. 2008, 582). We found that tip1;3 and tip5;1 homozygous mutant plants showed significantly reduced pollen tube length under nitrogen starvation. This data suggests that AtTIP1;3 and AtTIP5;1 are involved in nitrogen metabolism during pollen tube elongation. To understand the specific role of both TIPs, we generated transgenic plants that overexpress GFP-AtTIP5;1 and GFPAtTIP1; 3 fusion proteins studying their subcellular localization.

Published
2009

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