Adaptive radiation of Arctic charr (Salvelinus alpinus) in three Norwegian lakes - niche segregation, phenotypic and genetic variation

Å forstå hvordan økologiske og fysiske faktorer fører til opprinnelsen av nye arter, og hvilke faktorer som former ny intraspesifikk diversitet, er den “hellige gral” i evolusjonær biologi. Adaptiv radiasjon er den evolusjonære prosessen som kan føre til diversifisering av fenotyper og genotyper i ulike miljøer, og som kan splitte en forfaders form eller linje i nye former og arter. I den økologiske artsdannelsesprosessen vil lokal tilpasning gjennom naturlig seleksjon drive oppsplittingen av populasjoner, noe som vil føre til evolusjon av reproduktiv isolasjon og dermed dannelsen av nye økotyper, morfer, populasjoner og til slutt arter. Et godt eksempel på en polymorf art er røya (Salvelinus alpinus) som kan ha ulike nisjer (det vil si tilpasning til spesifikke abiotiske og biotiske forhold) i en innsjø. Spesialiseringen til en bestemt nisje kan favorisere divergensen mellom morfene, noe som kan lede til forskjeller i utseende, vekst, kjønnsmodning, gytetid og sted, og over tid utvikle reproduktive barrierer mellom morfene. Denne doktorgradsavhandlingen fokuserer på fenotypisk og genetisk divergens av røyemorfer. Hovedmålet er å undersøke nisjesegregering på trofisk nivå (det vil si diettvalg og habitatbruk), ved å studere morfologiske og genetiske forskjeller mellom røyemorfer fra tre forskjellige ferskvannsystemer i Norge (Tinnsjøen, Tårnvatn og Skøvatn). To røyemorfer ble funnet eksisterende sammen i Skøvatn, tre morfer i Tårnvatn, og fire i Tinnsjøen. To nye morfer ble funnet i Tinnsjøen og Skøvatn. Alle morfene viste forskjeller i livshistorie, genetikk, fenotype, diettvalg og habitatbruk. De fiskespisende morfene ernærte seg hovedsakelig av fisk, og ble funnet i den profundale delen av Tinnsjøen og Tårnvatn. Planktivore morfer spiste hovedsakelig dyreplankton, og ble funnet i flere ulike habitater i disse tre innsjøene. Livshistoriekarakterer og habitatbruk var lignende hos de småvokste dypvannsmorfene, men morfen i Skøvatn viste forskjeller i diettvalg sammenlignet med morfen fra Tårnvatn. Den nye dypvannsmorfen som ble funnet i den dypere delen av Tinnsjøen har likhetstrekk med hulefisk som hvitt skinn, underutviklede øyne og små hjerneregioner. Parallell evolusjon kan være en forklaring for likhetene som er funnet blant noen av morfene i disse tre ferskvannssystemene. Funnene viser hvordan seleksjonspress kan føre til lignende resultater i samme miljøer, der fenotypisk plastisitet også kan være en viktig mekanisme i tidlige stadier av nisjespesialisering. Disse morfene er sannsynligvis i en økologisk artsdannelsesprosess, der naturlig seleksjon spiller en viktig rolle i den adaptive divergensen av morfer, og bidrar til reproduktiv isolasjon. Adaptiv radiasjon kan forklare tilpasninger og diversitet hos den polymorfe røya i ulike vann.Abstract Understanding the ecological and physical factors driving the origin of species, and which ones are shaping new intraspecific diversity, are the “holy grail” of evolutionary biology. Adaptive radiation is the evolutionary process that can generate diversification of phenotypes and genotypes across different environments, differentiating a single ancestor into different forms and species. Under ecological speciation, local adaptation through natural selection drives the divergence of populations, evolving reproductive isolation and leading to the formation of new eco morphs, populations, and ultimately, species. A good example of polymorphic species is Arctic charr (Salvelinus alpinus), which has the flexibility to occupy different niches (i.e. a specific range of abiotic and biotic factors that a species has specialised) in a lake. For example, in fish, the specialisation into a specific niche can favour divergence among morphs, showing differences in morphology, growth, maturity, spawning time and site, developing reproductive barriers among the morphs. This thesis focuses on phenotypic and genetic divergence of Arctic charr morphs. The main objectives are to investigate trophic niche segregation (i.e. diet choice and habitat use), morphological and genetic differences among sympatric Arctic charr morphs from three different lakes in Norway (Tinnsjøen, Tårnvatn and Skøvatn). Two Arctic charr morphs were found coexisting in Lake Skøvatn, three morphs in Lake Tårnvatn and four morphs in Lake Tinnsjøen. Two novel morphs were found in Lake Tinnsjøen and Skøvatn. All morphs showed divergence in life history, genetics, phenotype, diet and habitat use. The piscivore morphs fed mainly on fish and were found in the profundal habitat of Lake Tinnsjøen and Tårnvatn. The planktivore morphs were feeding mainly on zooplankton, and were found across different habitats from these three lakes. Life-history traits and habitat use was similar among the small-sized profundal morphs, but the morph in Skøvatn presented differences in diet choice compared to the morph from Lake Tårnvatn. Finally, the Abyssal morph was found in the deepprofundal habitat in Lake Tinnsjøen, presenting similarities with cave fish such as white coloration, reduced eyes and small brain regions. Parallel evolution could be responsible for the similarities found among some of the Arctic charr morphs across these three lakes. These findings show how selection pressures can sometimes lead to similar outcomes in similar environments. However, phenotypic plasticity may also be an important component during the early stages of niche specialization. These morphs are likely under ecological speciation, where natural selection could play an important role in the adaptive divergence of morphs, contributing to reproductive isolation. Arctic charr polymorphism could be a case of adaptive radiation, explaining their diversity across different freshwater systems

Critical Thinking Using Project-Based Learning: The Case of The Agroecological Market at the "Universitat Politècnica de València"

[EN] Higher education institutions play an important role in the transition processes to sustainable development through developing critical thinking (CT) in their students. The case of the Research Methodology course of the International Cooperation Master's degree at the Universitat Politecnica de Valencia is a paradigmatic case of experiential learning, where students face their own realities related to sustainable topics through an action research project with the Agroecological Market (AM). The learning methodology is project-based learning and helps the participants to deeply analyze problems related to the transition of socio-technical systems, such as sustainable food. The objective of this research was to analyze the contribution of project-based learning to students' critical thinking through a qualitative analysis of the pedagogical outputs obtained during the course. The analysis and results are structured in three dimensions of critical thinking: (i) students' critical attitude towards reality; (ii) students' ability to reason and analyze in order to form their own rigorous judgments; and (iii) students' capacity to construct and deconstruct their own experiences and meanings. The results show that project-based learning using a real-life scenario helped students reflect on their critical thinking and the challenges that our societies face for a transition to sustainability.This research was partially funded by the ADVANCED HUMAN CAPITAL FORMATION PROGRAM "ANID/DOCTORADO BECAS CHILE/2018-72190320".Aranguiz, P.; Palau-Salvador, G.; Belda, A.; Peris Peris, J. (2020). Critical Thinking Using Project-Based Learning: The Case of The Agroecological Market at the "Universitat Politècnica de València". Sustainability. 12(9):1-23. https://doi.org/10.3390/su12093553S123129Rotmans, J., Kemp, R., & van Asselt, M. (2001). More evolution than revolution: transition management in public policy. Foresight, 3(1), 15-31. doi:10.1108/14636680110803003Jorgenson, S. N., Stephens, J. C., & White, B. (2019). Environmental education in transition: A critical review of recent research on climate change and energy education. The Journal of Environmental Education, 50(3), 160-171. doi:10.1080/00958964.2019.1604478Avelino, F., & Wittmayer, J. M. (2015). Shifting Power Relations in Sustainability Transitions: A Multi-actor Perspective. Journal of Environmental Policy & Planning, 18(5), 628-649. doi:10.1080/1523908x.2015.1112259Geels, F. W. (2002). Technological transitions as evolutionary reconfiguration processes: a multi-level perspective and a case-study. Research Policy, 31(8-9), 1257-1274. doi:10.1016/s0048-7333(02)00062-8Farla, J., Markard, J., Raven, R., & Coenen, L. (2012). Sustainability transitions in the making: A closer look at actors, strategies and resources. Technological Forecasting and Social Change, 79(6), 991-998. doi:10.1016/j.techfore.2012.02.001Jenkins, K., Sovacool, B. K., & McCauley, D. (2018). Humanizing sociotechnical transitions through energy justice: An ethical framework for global transformative change. Energy Policy, 117, 66-74. doi:10.1016/j.enpol.2018.02.036Stephens, J. C. (2019). Energy Democracy: Redistributing Power to the People Through Renewable Transformation. Environment: Science and Policy for Sustainable Development, 61(2), 4-13. doi:10.1080/00139157.2019.1564212Heffron, R. J., & McCauley, D. (2018). What is the ‘Just Transition’? Geoforum, 88, 74-77. doi:10.1016/j.geoforum.2017.11.016Adlong, W. (2012). 100% Renewables as a Focus for Environmental Education. Australian Journal of Environmental Education, 28(2), 125-155. doi:10.1017/aee.2013.5Freire, P. (1976). Literacy and the possible dream. Prospects, 6(1), 68-71. doi:10.1007/bf02220134Colás-Bravo, P., Magnoler, P., & Conde-Jiménez, J. (2018). Identification of Levels of Sustainable Consciousness of Teachers in Training through an E-Portfolio. Sustainability, 10(10), 3700. doi:10.3390/su10103700González Morales, A. L. (2019). Affective Sustainability. The Creation and Transmission of Affect through an Educative Process: An Instrument for the Construction of more Sustainable Citizens. Sustainability, 11(15), 4125. doi:10.3390/su11154125Cañabate, D., Serra, T., Bubnys, R., & Colomer, J. (2019). Pre-Service Teachers’ Reflections on Cooperative Learning: Instructional Approaches and Identity Construction. Sustainability, 11(21), 5970. doi:10.3390/su11215970Straková, Z., & Cimermanová, I. (2018). Critical Thinking Development—A Necessary Step in Higher Education Transformation towards Sustainability. Sustainability, 10(10), 3366. doi:10.3390/su10103366Díaz-Iso, A., Eizaguirre, A., & García-Olalla, A. (2019). Extracurricular Activities in Higher Education and the Promotion of Reflective Learning for Sustainability. Sustainability, 11(17), 4521. doi:10.3390/su11174521Urquidi-Martín, A., Tamarit-Aznar, C., & Sánchez-García, J. (2019). Determinants of the Effectiveness of Using Renewable Resource Management-Based Simulations in the Development of Critical Thinking: An Application of the Experiential Learning Theory. Sustainability, 11(19), 5469. doi:10.3390/su11195469Vogler, J. S., Thompson, P., Davis, D. W., Mayfield, B. E., Finley, P. M., & Yasseri, D. (2017). The hard work of soft skills: augmenting the project-based learning experience with interdisciplinary teamwork. Instructional Science, 46(3), 457-488. doi:10.1007/s11251-017-9438-9HMELO-SILVER, C. E., DUNCAN, R. G., & CHINN, C. A. (2007). Scaffolding and Achievement in Problem-Based and Inquiry Learning: A Response to Kirschner, Sweller, and Clark (2006). Educational Psychologist, 42(2), 99-107. doi:10.1080/00461520701263368JENSEN, B. B. (2004). Environmental and health education viewed from an action‐oriented perspective: a case from Denmark. Journal of Curriculum Studies, 36(4), 405-425. doi:10.1080/0022027032000167235Saiz Sánchez, C., & Fernández Rivas, S. (2012). Pensamiento crítico y aprendizaje basado en problemas cotidianos. REDU. Revista de Docencia Universitaria, 10(3), 325. doi:10.4995/redu.2012.6026Ortega-Sánchez, D., & Jiménez-Eguizábal, A. (2019). Project-Based Learning through Information and Communications Technology and the Curricular Inclusion of Social Problems Relevant to the Initial Training of Infant School Teachers. Sustainability, 11(22), 6370. doi:10.3390/su11226370Occhipinti. (2019). A Problem-Based Learning Approach Enhancing Students’ Awareness of Natural Risks and Hazards in Italian Schools. Geosciences, 9(7), 283. doi:10.3390/geosciences9070283Butler, H. A. (2012). Halpern Critical Thinking Assessment Predicts Real-World Outcomes of Critical Thinking. Applied Cognitive Psychology, 26(5), 721-729. doi:10.1002/acp.2851Ennis, R. H. (2016). Critical Thinking Across the Curriculum: A Vision. Topoi, 37(1), 165-184. doi:10.1007/s11245-016-9401-4Shephard, K., & Egan, T. (2018). Higher Education for Professional and Civic Values: A Critical Review and Analysis. Sustainability, 10(12), 4442. doi:10.3390/su10124442Facione, P. A. (2000). The Disposition Toward Critical Thinking: Its Character, Measurement, and Relationship to Critical Thinking Skill. Informal Logic, 20(1). doi:10.22329/il.v20i1.2254Steed, E. A., & Shapland, D. (2019). Adapting Social Emotional Multi-Tiered Systems of Supports for Kindergarten Classrooms. Early Childhood Education Journal, 48(2), 135-146. doi:10.1007/s10643-019-00996-8Sanders, K. E., Molgaard, M., & Shigemasa, M. (2019). The relationship between culturally relevant materials, emotional climate, ethnic composition and peer play in preschools for children of color. Journal for Multicultural Education, 13(4), 338-351. doi:10.1108/jme-02-2019-0014McCusker, S. (2019). Everybody’s monkey is important: LEGO® Serious Play® as a methodology for enabling equality of voice within diverse groups. International Journal of Research & Method in Education, 43(2), 146-162. doi:10.1080/1743727x.2019.1621831Cuéllar-Padilla, M., & Ganuza-Fernandez, E. (2018). We Don’t Want to Be Officially Certified! Reasons and Implications of the Participatory Guarantee Systems. Sustainability, 10(4), 1142. doi:10.3390/su10041142Clarke, P., & Oswald, K. (2010). Introduction: Why Reflect Collectively on Capacities for Change?1. IDS Bulletin, 41(3), 1-12. doi:10.1111/j.1759-5436.2010.00132.xWalker, M., McLean, M., Dison, A., & Peppin-Vaughan, R. (2009). South African universities and human development: Towards a theorisation and operationalisation of professional capabilities for poverty reduction. International Journal of Educational Development, 29(6), 565-572. doi:10.1016/j.ijedudev.2009.03.002Woodhill, J. (2010). Capacities for Institutional Innovation: A Complexity Perspective. IDS Bulletin, 41(3), 47-59. doi:10.1111/j.1759-5436.2010.00136.xAragón, A. O. (2010). A Case for Surfacing Theories of Change for Purposeful Organisational Capacity Development. IDS Bulletin, 41(3), 36-46. doi:10.1111/j.1759-5436.2010.00135.xAdelman, C. (1993). Kurt Lewin and the Origins of Action Research. Educational Action Research, 1(1), 7-24. doi:10.1080/0965079930010102Lewin, K. (1944). A Research Approach to Leadership Problems. Journal of Educational Sociology, 17(7), 392. doi:10.2307/2262546Fals-Borda, O. (1987). The Application of Participatory Action-Research in Latin America. International Sociology, 2(4), 329-347. doi:10.1177/026858098700200401Anselma, M., Chinapaw, M., & Altenburg, T. (2020). «Not Only Adults Can Make Good Decisions, We as Children Can Do That as Well» Evaluating the Process of the Youth-Led Participatory Action Research ‘Kids in Action’. International Journal of Environmental Research and Public Health, 17(2), 625. doi:10.3390/ijerph17020625Määttä, K., Hyvärinen, S., Äärelä, T., & Uusiautti, S. (2020). Five Basic Cornerstones of Sustainability Education in the Arctic. Sustainability, 12(4), 1431. doi:10.3390/su12041431Puccio, G. J., Burnett, C., Acar, S., Yudess, J. A., Holinger, M., & Cabra, J. F. (2018). Creative Problem Solving in Small Groups: The Effects of Creativity Training on Idea Generation, Solution Creativity, and Leadership Effectiveness. The Journal of Creative Behavior, 54(2), 453-471. doi:10.1002/jocb.38

Percepción y valoración de los programas de garantía social desde una doble perspectiva: Aprendices y formadores

Novenes Jornades de Foment de la Investigació de la FCHS (Any 2003-2004)Los motivos por los cuales elegimos este tema, “Percepción y valoración de los PGS desde una doble perspectiva: aprendices y formadores”, han sido, en primer lugar, por la utilidad que representa para nosotras, estudiantes de la carrera de Psicopedagogía y futuros Psicopedagogos, y en segundo lugar porque nos interesaba hacer un pequeño estudio de campo sobre la utilidad, funcionamiento,… de los Programas de Garantía Social. Los Programas de Garantía Social son una medida más de atención a la diversidad, con criterios de compensación educativa para los alumnos más desfavorecidos que no hayan alcanzado los objetivos de la ESO y que se encuentren en situación de desventaja sociocultural o laboral. Se pretende ofrecer a los jóvenes que necesitan de un tratamiento educativo alternativo la posibilidad de mejorar sus condiciones para acceder a la vida activa o para poder reinsertarse en el sistema reglado posteriormente. Para poder llevar a cabo esta investigación hemos recibido una colaboración totalmente desinteresada de tres entidades: CEE Hortolans de Burriana, CEE La Panderola de Villa-real y la Asociación Síndrome de Down de Castellón. partir de la información recopilada en todos ellos, a través de un cuestionario dirigido a profesores y alumnos, hemos podido obtener la información necesaria para llevar a cabo nuestra investigación y poder alcanzar los objetivos que plantearemos más adelante

El teatro como estrategia de trabajo cooperativo que genera cohesión en un aula de primaria

Treball Final de Grau en Mestre o Mestra d'Educació Primària. Codi: MP1040. Curs acadèmic: 2020/2021¿El teatro puede influir y ayudar en la cohesión grupal dentro del aula de Educación Primaria? Muchos son los autores que han defendido la teoría de utilizarlo en la educación y la han aplicado en sus aulas. Además de numerosos actores y pedagogos que defienden este arte como enriquecedor para todo aquel o aquella que lo practica. El presente trabajo ha consistido en realizar una obra de teatro con alumnos y alumnas de 4º de Educación Primaria. Estudiar a partir del estatus sociométrico de tres grupos, dos de ellos control y uno experimental, la inclusión y las habilidades sociales de los participantes. Así como fomentar el compromiso por el bien del conjunto, pues el alumnado va a formar parte de un proyecto común, el cual necesita la cooperación de todos y todas. Después de los dos meses de intervención, se ha conseguido ver una mejoría respecto a la inclusión, colaboración entre ellos/as, habilidades sociales y conocimiento del vocabulario específico del tema. Se ha observado cómo el miedo a la hora de hablar en público ha ido desapareciendo y el respeto entre ellos/as ha mejorado. Consideramos exitosa la intervención, ya que ha generado cambios significativos en la dinámica del grupo clase y cambios importantes en el alumnado con más carencias en habilidades sociales

Biogénesis e inserción en membranas de proteínas de movimiento de virus vegetales

RESUMEN La propagación de una infección viral en plantas está mediada por unas proteínas codificadas por el propio virus denominadas proteínas de movimiento (MP). Estas proteínas unen el genoma viral de forma cooperativa y sin especificidad de secuencia, formando unos complejos RNA-MP, que se asocian, en la mayoría de casos, al retículo endoplasmático (RE) para ser transportados muy posiblemente a través del citoesqueleto hacia los plasmodesmos, canales membranosos que interconectan las células en plantas. Una vez estos complejos alcanzan los plasmodesmos, el RNA viral es translocado a las células adyacentes a través de un mecanismo todavía desconocido. A pesar de la variabilidad entre las distintas familias virales en el número y tamaño de este tipo de proteínas, se ha descrito que muchas de estas MPs interaccionan con las membranas celulares. Sin embargo, la naturaleza de esta interacción y los mecanismos que subyacen a este fenómeno no se han explorado todavía. Así pues, el objetivo central de la presente tesis se ha basado en el estudio y caracterización de la asociación de estas proteínas con la membrana del RE. El virus objeto de estudio ha sido el Virus del Moteado del Clavel, que codifica dos MPs, p7, una proteína soluble capaz de unir el genoma viral y p9, que presenta dos regiones hidrofóbicas susceptibles de interaccionar con las membranas celulares. En primer lugar, mediante experimentos de transcripción/traducción in vitro se ha demostrado que p9 es una proteína integral de membrana que contiene dos fragmentos transmembrana y adopta una orientación N-/Cterminal citoplasmática. En segundo lugar, se ha caracterizado el mecanismo a través del cual p9 alcanza las membranas celulares. Los resultados obtenidos demuestran que la inserción de p9 tiene lugar de forma co-traduccional y es dependiente de SRP, un complejo ribonucleoproteico que, en general, participa en el direccionamiento de proteínas a la membrana del RE. Además, el virus explota la propia maquinaria celular responsable de la integración de las proteínas de membrana celulares. Así, el complejo Sec61 y la proteína TRAM participan en el proceso de inserción de p9. Entre los resultados obtenidos cabe destacar que (i) los segmentos transmembrana de este virus se integran en la membrana a través de un mecanismo secuencial y ordenado desde Sec61a a TRAM; y (ii) la proteína TRAM media la integración de esta proteína viral desempeñando una posible función de reclutamiento de segmentos transmembrana antes de que éstos particionen conjuntamente a la bicapa lipídica, una vez completada la traducción de la proteína. Finalmente, se ha realizado un estudio de los determinantes topológicos de la proteína que determinan su orientación en la membrana. Se ha explorado la contribución de toda una serie de parámetros, que se han establecido como determinantes en el caso de proteínas de membrana de procariotas o eucariotas. Entre estos factores se encuentran la presencia de residuos cargados en la secuencia de la proteína, la hidrofobicidad de los fragmentos transmembrana, la longitud de dominios extramembranosos y/o la presencia de residuos aromáticos en las regiones flanqueantes de los propios segmentos transmembrana. Los resultados demuestran que la proteína viral p9 presenta la información topológica distribuida a lo largo de la secuencia de aminoácidos de la proteína. Esta estrategia impediría que la posible aparición de una mutación no conservativa en el gen de la proteína, proceso muy habitual durante la replicación de los genomas virales, alterara la orientación de la proteína en la membrana y en definitiva, comprometiese su función biológica. __________________________________________________________________________________________________The cell-to-cell movement of plant virus is assisted by the viral so-called movement proteins (MP). Functions assigned to these proteins include nucleic acid binding, targeting to the endoplasmic reticulum (ER), and modification of the size exclusion limit of the plasmodesmata, a membranous channel that connect adjacent cells. Although the number and size of these proteins vary from viral families it has been described that many of the viral MPs interact with the membranes but the nature of this interaction is not well defined yet. Therefore, the main goal of this study is the characterization of MPs interaction to the ER membranes. The Carnation Mottle Virus has been used as an experimental model. This virus encodes two MPs, a cytoplasmic soluble protein of 7 kDa, p7, which binds viral genome, and a hydrophobic protein of 9 kDa, p9, with two putative transmembrane segments. Firstly, it has been demonstrated that p9 is, in fact, an integral membrane protein containing two transmembrane segments and facing both N- and Cterminus to the cytosol. Secondly, it has been dissected the cellular pathway followed by p9 to reach the host membranes. This viral protein is targeted to ER membrane by the signal recognition particle, and the translocon components Sec61a and TRAM mediate p9 integration into the membrane. The unexpected results obtained in these studies are the following: (i) viral TM fragments integrate into the lipid bilayer through a sequentially ordered contact to Sec61a and TRAM; and (ii) TRAM mediates viral protein integration by collecting TM domains, which are only partitioned into the lipid bilayer after translation termination. Finally, it has been studied the topological determinants of p9 that govern the proper orientation of this viral membrane protein. It has been analysed contribution of different parameters such are distribution of positive residues along the protein sequence, hydrophobicity of transmembrane segments, length of extramembranous domains, and presence of aromatic residues flanking transmembrane domains. The results demonstrate that topological information of p9 is distributed along the amino acid sequence. This strategy could avoid any alteration of native topology of p9 due to a random mutation in the protein gene, a common process during viral genome replication

Supramolecular self-assembly structures from a di-Au(I) complex with a hinge-shaped ligand

Póster presentado en la XXXVII Reunión Bienal de la Real Sociedad Española de Química, celebrada en Donostia-San Sebastián (Spain) del 26 al 30 de mayo de 2019.Among N-heterocyclic carbenes (NHCs), polytopic NHC ligands have emerged as promising tools in the design of supramolecular structures.1 In this regard, our group of research designed fusedbis(imidazolinylidene) ligands with folded geometry and reported their coordination to Rh and Ir,2-3 and Pd.3 More recently, one of these hinge-shaped ligands allowed us to prepare the Au(I)-based dimetallic complex 1 (Scheme 1)

El perfil del psicopedagogo

Vuitenes Jornades de Foment de la Investigació de la FCHS (Any 2002-2003

Effect of subclinical mastitis on the yield and cheese-making properties of ewe's milk

[EN] This review covers an update of scientific knowledge about productive and technological consequences of subclinical mastitis in sheep milk. The literature reports individual milk yield losses of 2.6-43.1 %, being modulated by several factors as infection severity, production level, causal agents, and unilateral or bilateral IMI (1 or 2 infected glands, respectively). A compensatory increase of milk production from the uninfected gland when only one half was infected has been quantified in 6.6 %, compared with healthy halves of control sheep. This compensatory adaptation highlights the risk of underestimating subclinical mastitis in sheep. The mammary gland response is quick and milk yield losses in absolute terms remained constant within the following weeks, both when infection appear during lactation and when it is present from lambing. With respect to the changes on main components in milk due to subclinical mastitis it has been clearly established a decrease in the concentration of lactose and an increase of that of whey proteins. The role played by lactose as an osmotic regulator results in a more accentuated decrease of its concentration in milk. This is why lactose is considered at present as a reliable potential indicator of subclinical mastitis. Whey proteins increase as a result of the increase of the blood-milk barrier permeability and the increased proteolysis of caseins. However, the content in milk of fat and casein are modified depending on the magnitude of milk yield reduction, being affected by a concentration or dilution effect. In any case, the ratio casein to protein (parameter independent of the milk volume) decreases as a result of infection. The impairment of physical and chemical characteristics due to decreased udder health status is the responsible of the negative effect of increased SCC on the coagulation properties of milk, the curd yield and the quality of cheese. Low ratio of casein to protein in high bulk tank SCC milk enhances the extension of the rennet coagulation time (RCT) and curd firming time (k20) because there are more serum proteins and the stability of casein micelles are reduced as a result of hydrolysis. Those changes in turn led to poor syneresis, lower cheese yield, increased moisture content and lower fat and protein content in cheese. Finally, there is a favourable relationship between lactose and milk technological properties because the decrease of this component in case of mastitis is associated with an increase of milk pH. Thus, the three parameters, SCC, pH, and lactose affect, contemporarily and independently, milk quality and coagulation properties, and this is why have been highlighted as potential indicators traits for improving cheese-making ability of sheep milk.This review is based on knowledge gained during work financially supported by means of a research fellowship from the regional government of Valencia ("Generalitat Valenciana").Martí-De Olives, A.; Peris Ribera, CJ.; Molina Pons, MP. (2020). Effect of subclinical mastitis on the yield and cheese-making properties of ewe's milk. Small Ruminant Research. 184:1-7. https://doi.org/10.1016/j.smallrumres.2019.106044S17184Albenzio, M., Marino, R., Caroprese, M., Santillo, A., Annicchiarico, G., & Sevi, A. (2004). Quality of milk and of Canestrato Pugliese cheese from ewes exposed to different ventilation regimens. 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Redox-Switchable Cycloisomerization of Alkynoic Acids with Napthalenediimide-Derived N-Heterocyclic Carbene Complexes

Two naphthalene-diimide (NDI) bis-imidazolium salts have been used as N-heterocyclic carbene (NHC) precursors for the preparation of NDI-functionalized complexes of rhodium and iridium of general formula [MCl(NDI-NHC)(COD)] (M=Rh, Ir; NDI-NHC=NDI-functionalized NHC ligand). Comparison of the IR spectra of the complexes [IrCl(NDI-NHC)(CO)2] and their related one- and two-electron reduced forms, reveal that each one-electron reduction produces a decrease of the average ν(CO) of 9–10 cm−1, indicating a significant enhancement of the electron-richness of the metal. The [MCl(NDI-NHC)(COD)] complexes were tested in the catalytic cycloisomerization of alkynoic acids. The one-electron reduced forms showed greatly enhanced activities. For the cyclization of 5-hexynoic acid, the two-electron reduction of the ligand produced further enhancement of the catalytic activity, therefore showing that the catalyst can switch between three redox species with three distinct catalytic activities.Funding for open access charge: CRUE-Universitat Jaume IFunding for open access charge: CRUE-Universitat Jaume IWe gratefully acknowledge financial support from the Ministerio de Ciencia y Universidades (PGC2018-093382-B-I00), Generalitat Valenciana (AICO/2019/149), and the Universitat Jaume I (UJI-B2017-07 and UJI-B2018-46). S.G. thanks the Juan de la Cierva Incorporación program (IJC2019-039982-I). We are grateful to the Serveis Centrals d'Instrumentació Científica (SCIC-UJI) for providing with spectroscopic facilities