Functionalization and Characterization of Magnetic Nanoparticles for the Detection of Ferritin Accumulation in Alzheimer's Disease

Early diagnosis in Alzheimer's disease (AD), prior to the appearance of marked clinical symptoms, is critical to prevent irreversible neuronal damage and neural malfunction that lead to dementia and death. Therefore, there is an urgent need to generate new contrast agents which reveal by a noninvasive method the presence of some of the pathological signs of AD. In the present study, we demonstrate for the first time a new nanoconjugate composed of magnetic nanoparticles bound to an antiferritin antibody, which has been developed based on the existence of iron deposits and high levels of the ferritin protein present in areas with a high accumulation of amyloid plaques (particularly the subiculum in the hippocampal area) in the brain of a transgenic mouse model with five familial AD mutations. Both in vitro and after intravenous injection, functionalized magnetic nanoparticles were able to recognize and bind specifically to the ferritin protein accumulated in the subiculum area of the AD transgenic mice.Fil: Fernández Cabada, Tamara. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Politécnica de Madrid; EspañaFil: Martínez Serrano, Alberto. Consejo Superior de Investigaciones Científicas; España. Universidad Autónoma de Madrid; EspañaFil: Cussó, Lorena. Instituto de Investigacion Sanitaria Gregorio Marañón; España. Universidad Carlos III de Madrid; España. Centro de Investigación Biomédica en Red de Salud Mental; EspañaFil: Desco, Manuel. Instituto de Investigacion Sanitaria Gregorio Marañón; España. Centro de Investigación Biomédica en Red de Salud Mental; España. Universidad Carlos III de Madrid; EspañaFil: Ramos Gómez, Milagros. Universidad Politécnica de Madrid; Españ

Dos herramientas bioinformáticas para el análisis de genomas de bacterias fitopatógenas

Comunicación seleccionada como presentación oral plenariaLos avances en tecnología de secuenciación han supuesto una cosiderable reducción en costo y tiempo a la hora de obtener genomas bacterianos completos. Es cada vez más frecuente, pues, secuenciar los genomas de las cepas bacterianas que son de particular interés, creciendo a su vez la necesidad de desarrollar herramientas computacionales para el análisis de las secuencias obtenidas. En lo que a bacterias patógenas se refiere, son de especial relevancia herramientas de detección de genes implicados en virulencia. En este contexto presentamos TTFShunter y ViRfAt, dos aplicaciones bioinformáticas que tienen como objeto facilitar la identificación genómica del arsenal de virulencia de bacterias secuenciadas. TTFShunter (http://bacterial-virulence-factors.cbgp.upm.es/T346Hunter) es una herramienta online de predicción de sistemas de secreción de tipo III, IV y VI (T3SS, T4SS y T6SS, respectivamente). Mediante exhaustivas búsquedas en la bibliografía científica, se construyó una base de datos de las secuencias genómicas correspondientes a los distintos componentes de los T3SS, T4SS y T6SS. Dada la secuencia de ADN de un genoma bacteriano, TTFShunter hace uso de la base de datos anterior para localizar regiones enriquecidas en dichos componentes. ViRfAt es también una aplicación web, en este caso de anotación de factores genómicos asociados a virulencia en planta. ViRfAt busca en genomas bacterianos una batería de factores de virulencia que incluye efectores, fitotoxinas, antibióticos, enzimas extracelulares, hormonas vegetales, adhesinas o sideróforos. Estos factores están incluidos en una base de datos manualmente curada, en cuya elaboración han participado diversos grupos de investigación nacionales expertos en bacterias fitopatógenas. Ambas herramientas presentan una sencilla interfaz web fácil de utilizar, donde una vez analizado el genoma de entrada los resultados se presentan gráficamente a través de un documento HTML intuitivo y fácilmente interpretable. TTFShunter y ViRfAt representan dos herramientas de gran ayuda a microbiológos para la identificación de factores bacterianos de virulencia en planta.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Multimodular Bio-Inspired Organized Structures Guiding Long-Distance Axonal Regeneration

Axonal bundles or axonal tracts have an aligned and unidirectional architecture present in many neural structures with different lengths. When peripheral nerve injury (PNI), spinal cord injury (SCI), traumatic brain injury (TBI), or neurodegenerative disease occur, the intricate architecture undergoes alterations leading to growth inhibition and loss of guidance through large distance. In order to overcome the limitations of long-distance axonal regeneration, here we combine a poly-L-lactide acid (PLA) fiber bundle in the common lumen of a sequence of hyaluronic acid (HA) conduits or modules and pre-cultured Schwann cells (SC) as cells supportive of axon extension. This multimodular preseeded conduit is then used to induce axon growth from a dorsal root ganglion (DRG) explant placed at one of its ends and left for 21 days to follow axon outgrowth. The multimodular conduit proved effective in promoting directed axon growth, and the results may thus be of interest for the regeneration of long tissue defects in the nervous system. Furthermore, the hybrid structure grown within the HA modules consisting in the PLA fibers and the SC can be extracted from the conduit and cultured independently. This “neural cord” proved to be viable outside its scaffold and opens the door to the generation of ex vivo living nerve in vitro for transplantation.This research was funded by the Spanish Government’s State Research Agency (AEI) through projects DPI2015-72863-EXP and RTI2018-095872-B-C22/ERDF. Laura Rodríguez Doblado acknowledges scholarship FPU15/04975 of the Spanish Ministry of Education, Culture, and Sports

Portable X-ray Fluorescence analysis of Levantine and Schematic art pigments from the River Vero Shelters (Huesca, NE Spain)

The River Vero canyon (Huesca, Spain) contains an exceptional archaeological legacy with more than sixty rock shelters with cave paintings and forms part of the World Heritage ‘Rock Art of the Mediterranean Basin on the Iberian Peninsula’. This study presents the results of the in situ and non-destructive multi-elemental composition analysis of the pigments used in eight of the main shelters through portable X-ray fluorescence spectroscopy (pXRF). Specifically, the cave paintings of the rock shelters of Chimiachas, Muriecho, and Arpán (Levantine Art); and Mallata, Barfaluy, Quizans, Lecina Superior, and Forau del Cocho (Schematic Art) were investigated. The red pigments, based on iron minerals, were the most abundant in all the River Vero rock shelters, with Fe contents in the 0.51–3.06% range. The iron contents of the paintings of Mallata B1 and I, Muriecho, and Forau del Cocho were higher than those of Arpán, Barfaluy, Lecina, and Chimiachas rock-shelters; and, in turn, these were higher than those of Quizans, pointing to noticeable differences in the degree of conservation. Black pigments, in the absence of manganese, were associated with bone char or carbon black. Through the phosphorus content, evidence is provided of the use of bone phosphates as a component of the paints, either as a filler or as a binder. Geological studies indicate that the detected gypsum is of external origin, probably associated with gypsum-rich atmospheric dust. The reported pXRF analysis of this large set of paintings may serve as a basis for future characterization studies involving other portable chemical analysis techniques

Criteria of the peer-review process for publication of experimental and quasi-experimental research in Psychology

Experimental research in Psychology is characterized by ensuring a method that guarantees objectivity, reliability, validity and replication of results. In this theoretical study we have elaborated a set of criteria for the preparation and review of quasiexperimental and experimental research manuscripts, which follows such methodological objective dictates. These criteria are based on a review of structural aspects in experimental research, in the modern theory of psychological theorization, and in the validity theory of scientific research. All these aspects are complemented with those proposed in revisions about empirically-based, and statistically-based peer-review systems. We distinguish between essential, obligatory, and complementary criteria. These criteria are organized according to a measuring tool –the ExperimenCheck system-, including report characteristics, antecedents, theoretical development, design, analysis and interpretation of results, format and bibliographical sources. We also introduce the general guidelines of a reviewing process that fulfils scientific criteria, using the proposed evaluative guideline as the main organizing principle.La investigación experimental en Psicología se rige por un método que garantiza la objetividad, la fiabilidad, la validez y la reproducción de los resultados. En este estudio teórico se proponen un conjunto de criterios para la preparación y revisión de manuscritos de investigación experimental y cuasi-experimental que sigue precisamente tales dictados metodológicos de objetividad. Tales criterios se basan en una revisión de los aspectos estructurales propios de la metodología de investigación experimental y la teoría moderna de teorización psicológica, así como en la teoría de validez. Dichos aspectos se complementaron además con lo que se ha publicado sobre el propio proceso de revisión, tanto desde el punto de vista empírico como estadísticometodológico. Se distingue entre criterios básicos, obligatorios, y criterios complementarios. Los criterios se organizan según el sistema ExperimenCheck, un instrumento de medida que abarca las características del informe, los antecedentes, el desarrollo teórico, el diseño, análisis e interpretación de resultados, formato y fuentes documentales. Se presentan también las directrices generales de un proceso de revisión basado en dicho sistema de evaluación.A investigação experimental em Psicologia rege-se por um método que garante a objectividade, a fidelidade, a validade e a reprodução dos resultados. Neste estudo teórico propõe-se um conjunto de critérios para a preparação e revisão de manuscritos de investigação experimental e quase-experimental que segue precisamente tais critérios metodológicos de objectividade. Tais critérios baseiam-se numa revisão dos aspectos estruturais próprios da metodologia de investigação experimental e a teoria moderna de teorização psicológica, assim como na teoria da validade. Tais aspectos completam o que se publicou sobre o próprio processo de revisão tanto do ponto de vista empírico como estatístico-metodologico. Distingue-se entre critérios básicos, obrigatórios, e critérios complementares. Os critérios organizam-se segundo o sistema Experimen Check, um instrumento de medida que abarca as características do relatório, os antecedentes, o desenvolvimento teórico, o plano, a análise e a interpretação de resultados, formato e fontes documentais. Apresentam-se também as directrizes gerais de um processo de revisão baseado no dito sistema de avaliação

Engineered axon tracts within tubular biohybrid scaffolds

Injuries to the nervous system that involve the disruption of axonal pathways are devastating to the individual and require specific tissue engineering strategies. Here we analyse a cells-biomaterials strategy to overcome the obstacles limiting axon regenerationin vivo, based on the combination of a hyaluronic acid (HA) single-channel tubular conduit filled with poly-L-lactide acid (PLA) fibres in its lumen, with pre-cultured Schwann cells (SCs) as cells supportive of axon extension. The HA conduit and PLA fibres sustain the proliferation of SC, which enhance axon growth acting as a feeder layer and growth factor pumps. The parallel unidirectional ensemble formed by PLA fibres and SC tries to recapitulate the directional features of axonal pathways in the nervous system. A dorsal root ganglion (DRG) explant is planted on one of the conduit's ends to follow axon outgrowth from the DRG. After a 21 d co-culture of the DRG + SC-seeded conduit ensemble, we analyse the axonal extension throughout the conduit by scanning, transmission electronic and confocal microscopy, in order to study the features of SC and the grown axons and their association. The separate effects of SC and PLA fibres on the axon growth are also experimentally addressed. The biohybrid thus produced may be considered a synthetic axonal pathway, and the results could be of use in strategies for the regeneration of axonal tracts

Axonal extension from dorsal root ganglia on fibrillar and highly aligned poly(lactic acid)-polypyrrole substrates obtained by two different techniques: Electrospun nanofibres and extruded microfibres

[EN] The biological behaviour of Schwann cells (SCs) and dorsal root ganglia (DRG) on fibrillar, highly aligned and electroconductive substrates obtained by two different techniques is studied. Mats formed by nanometer-sized fibres of poly(lactic acid) (PLA) are obtained by the electrospinning technique, while bundles formed by micrometer-sized extruded PLA fibres are obtained by grouping microfibres together. Both types of substrates are coated with the electrically conductive polymer polypyrrole (PPy) and their morphological, physical and electrical characterization is carried out. SCs on micrometer-sized substrates show a higher motility and cell-cell interaction, while a higher cell-material interaction with a lower cell motility is observed for nanometer-sized substrates. This higher motility and cell-cell interaction of SCs on the micrometer-sized substrates entails a higher axonal growth from DRG, since the migration of SCs from the DRG body is accelerated and, therefore, the SCs tapestry needed for the axonal growth is formed earlier on the substrate. A higher length and area of the axons is observed for these micrometer-sized substrates, as well as a higher level of axonal sprouting when compared with the nanometer-sized ones. These substrates offer the possibility of being electrically stimulated in different tissue engineering applications of the nervous system.The authors acknowledge financing from the Spanish Government's State Research Agency (AEI) through projects DPI2015-72863-EXP and RTI2018-095872-B-C22/ERDF. FGR acknowledges scholarship FPU16/01833 of the Spanish Ministry of Universities. We thank the Electron Microscopy Service at the UPV, where the FESEM images were obtainedGisbert-Roca, F.; Más Estellés, J.; Monleón Pradas, M.; Martínez-Ramos, C. (2020). Axonal extension from dorsal root ganglia on fibrillar and highly aligned poly(lactic acid)-polypyrrole substrates obtained by two different techniques: Electrospun nanofibres and extruded microfibres. International Journal of Biological Macromolecules. 163:1959-1969. https://doi.org/10.1016/j.ijbiomac.2020.09.181S19591969163Houschyar, K. S., Momeni, A., Pyles, M. N., Cha, J. Y., Maan, Z. N., Duscher, D., … Schoonhoven, J. van. (2016). The Role of Current Techniques and Concepts in Peripheral Nerve Repair. Plastic Surgery International, 2016, 1-8. doi:10.1155/2016/4175293Daly, W., Yao, L., Zeugolis, D., Windebank, A., & Pandit, A. (2011). A biomaterials approach to peripheral nerve regeneration: bridging the peripheral nerve gap and enhancing functional recovery. 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Fabrication of conductive electrospun silk fibroin scaffolds by coating with polypyrrole for biomedical applications. Bioelectrochemistry, 85, 36-43. doi:10.1016/j.bioelechem.2011.11.008Sun, X., Peng, J., Zhou, J., Wang, Y., Cheng, L., & Wu, Z. (2016). Preparation of polypyrrole-embedded electrospun poly(lactic acid) nanofibrous scaffolds for nerve tissue engineering. Neural Regeneration Research, 11(10), 1644. doi:10.4103/1673-5374.193245George, P. M., Lyckman, A. W., LaVan, D. A., Hegde, A., Leung, Y., Avasare, R., … Sur, M. (2005). Fabrication and biocompatibility of polypyrrole implants suitable for neural prosthetics. Biomaterials, 26(17), 3511-3519. doi:10.1016/j.biomaterials.2004.09.037Lunt, J. (1998). Large-scale production, properties and commercial applications of polylactic acid polymers. Polymer Degradation and Stability, 59(1-3), 145-152. doi:10.1016/s0141-3910(97)00148-1Ramot, Y., Haim-Zada, M., Domb, A. J., & Nyska, A. (2016). 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E., & Zadpoor, A. A. (2020). Substrate curvature as a cue to guide spatiotemporal cell and tissue organization. Biomaterials, 232, 119739. doi:10.1016/j.biomaterials.2019.119739Rolli, C. G., Nakayama, H., Yamaguchi, K., Spatz, J. P., Kemkemer, R., & Nakanishi, J. (2012). Switchable adhesive substrates: Revealing geometry dependence in collective cell behavior. Biomaterials, 33(8), 2409-2418. doi:10.1016/j.biomaterials.2011.12.012Doxzen, K., Vedula, S. R. K., Leong, M. C., Hirata, H., Gov, N. S., Kabla, A. J., … Lim, C. T. (2013). Guidance of collective cell migration by substrate geometry. Integrative Biology, 5(8), 1026. doi:10.1039/c3ib40054aKim, Y., Haftel, V. K., Kumar, S., & Bellamkonda, R. V. (2008). The role of aligned polymer fiber-based constructs in the bridging of long peripheral nerve gaps. Biomaterials, 29(21), 3117-3127. doi:10.1016/j.biomaterials.2008.03.042Schnell, E., Klinkhammer, K., Balzer, S., Brook, G., Klee, D., Dalton, P., & Mey, J. (2007). Guidance of glial cell migration and axonal growth on electrospun nanofibers of poly-ε-caprolactone and a collagen/poly-ε-caprolactone blend. Biomaterials, 28(19), 3012-3025. doi:10.1016/j.biomaterials.2007.03.00

Electrical Stimulation Increases Axonal Growth from Dorsal Root Ganglia Co-Cultured with Schwann Cells in Highly Aligned PLA-PPy-Au Microfiber Substrates

[EN] Nerve regeneration is a slow process that needs to be guided for distances greater than 5 mm. For this reason, different strategies are being studied to guide axonal growth and accelerate the axonal growth rate. In this study, we employ an electroconductive fibrillar substrate that is able to topographically guide axonal growth while accelerating the axonal growth rate when subjected to an exogenous electric field. Dorsal root ganglia were seeded in co-culture with Schwann cells on a substrate of polylactic acid microfibers coated with the electroconductive polymer polypyrrole, adding gold microfibers to increase its electrical conductivity. The substrate is capable of guiding axonal growth in a highly aligned manner and, when subjected to an electrical stimulation, an improvement in axonal growth is observed. As a result, an increase in the maximum length of the axons of 19.2% and an increase in the area occupied by the axons of 40% were obtained. In addition, an upregulation of the genes related to axon guidance, axogenesis, Schwann cells, proliferation and neurotrophins was observed for the electrically stimulated group. Therefore, our device is a good candidate for nerve regeneration therapies.This research was funded by the Spanish Government's State Research Agency (AEI) through project RTI2018-095872-B-C22/ERDF and by RISEUP project FetOpen in H2020 Program: RISEUP 964562 H2020 FetOpen program.Gisbert Roca, F.; Serrano Requena, S.; Monleón Pradas, M.; Martínez-Ramos, C. (2022). Electrical Stimulation Increases Axonal Growth from Dorsal Root Ganglia Co-Cultured with Schwann Cells in Highly Aligned PLA-PPy-Au Microfiber Substrates. International Journal of Molecular Sciences. 23:1-22. https://doi.org/10.3390/ijms231263621222

Response to fungal exudates of the rhizosphere isolate Pseudomonas sp. UMAF110 involves a GGDEF/EAL domain-containing protein

Pseudomonas sp. UMAF110, isolated from rhizosphere soil in Spain, display in vitro antagonism towards the pythopathogenic fungus Rosellinia necatrix and is able grow in fungal exudates (BM-RE medium). A transposon mutant library of this strain was constructed and several mutants were selected by their reduced competitiveness in BM-RE medium. Pseudomonas sp. UMAF110-G3, which contains the transposon into a gene encoding a putative REC/PAS/GGDEF/EAL protein, was selected for further characterization. Blastn searches using the sequence of the gene interrupted by the transposon in UMAF110-G3, here called cmpA (c-di-GMP Metabolizing Protein), yielded a single positive hit (98% cover, 78% identity) with a gene from a terpene-degrading Pseudomonas sp. strain isolated from soil. Context analysis of the cmpA gene in Pseudomonas sp. UMAF110 showed that this gene is located downstream from several genes involved in flagellar motility/chemotaxis. RT-PCR experiments further confirmed that cmpA form a transcriptional unit with the che gene cluster. Expression analysis of cmpA by qRT-PCR clearly showed upregulation of this gene after transfer of Pseudomonas sp. UMAF110 cells to BM-RE medium, suggesting a role for this operon in response to fungal exudates. Deletion of cmpA in Pseudomonas sp. UMAF110 did not affect the ability of the strain to form biofilms under the conditions tested. However, overexpression of wild type CmpA in Pseudomonas putida KT2440 negatively regulated biofilm formation in this strain. Together, these results suggest that CmpA could be involved in signal transduction pathways regulating flagellar motility/chemotaxis in response to fungal exudates.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

An Examination of the Excess Thermodynamic Properties of Flexible Molecules from a Molecular Modelling Perspective

Excess thermodynamic properties provide fundamental information on the intermolecular interactions in multicomponent fluid mixtures. However, very often only phase equilibria is used to test the accuracy of any theory or molecular model describing the solution thermodynamic behaviour. Although this approach is valid and often sufficient, some situations require stronger tests to determine whether a model and/or theory can provide a realistic description of a particular system. Excess properties estimation is a valuable test for this purpose because excess properties are very sensitive to the molecular model details. The goal of this work is to show how simple models, with a reduced number of molecular parameters, are able to predict accurately excess thermodynamic properties. We concentrate on binary mixtures formed by different models of flexible molecules. In particular, we focus on two general models: the fully-flexible tangentially bonded Lennard–Jones chains model described with the SAFT VR [J. Chem. Phys. 106 (1997) 4168] approach, and the united-atom model combined with Monte Carlo simulation, in both cases applied to the description of short chain alkane mixtures (from methane to propane). While the first model does not consider intramolecular interactions and the bond length equals the monomer size, the second one incorporates a more realistic description. Although the molecular models are relatively simple, they are able to describe most of the microscopic features of real chainlike molecules. The predictions obtained from SAFT-VR and simulation are compared with available experimental data, and the agreement is good for a wide range of thermodynamic conditions. In addition to the vapour–liquid equilibria, both theory and simulation are able to characterize the most relevant features of two important excess thermodynamic properties, excess volume and enthalpy.We acknowledge financial support from project number FIS2011-13119-E, Red de Simulación Molecular (RdSiMol) of Sub- programa de Acciones Complementaria del Ministerio de Ciencia e Innovación. FJB acknowledges financial support from project number FIS2010-14866, and MMP from project FIS2012-33621 (this one co-financed with EU FEDER funds), both from of the Spanish Ministerio, Dirección de Ciencia e Innovación. Additional support from Universidad de Huelva and Junta de Andalucía is also acknowledged. MMP also acknowledges CESGA (www.cesga.es, Santiago de Compostela, Spain) for providing access to computing facilities