Host-parasite dynamics in a natural system

The Red Queen Hypothesis postulates that reciprocal selection arising from host-parasite interactions should accelerate evolutionary rates through the need for continual adaptation and counter-adaptation. A process driving such rapid reciprocal adaptation is referred to as negative frequency-dependent selection, in which the most common genotypes decrease over time because they have a higher probability of becoming infected by coevolving parasites. This proposed mechanism of host-parasite coevolution was commonly tested in laboratory experiments under controlled conditions. Regarding field investigations of natural populations, temporal changes in relative frequencies of genotypes were mostly tested for host only, because tracking parasite dynamics over time remained difficult. As parasite population dynamics are highly sensitive to environmental changes, studies under natural conditions are essential to understand host-parasite coevolution. The commonly explored model system to address coevolutionary questions are the water fleas of the genus Daphnia and their microparasites. In this PhD thesis, I analysed the population structure of two major microparasites of Daphnia: Caullerya mesnili (Chapters 2 and 3) and microsporidia (Chapter 4). First, in Chapter 2, I developed a new bioinformatic pipeline to analyse molecular data generated by next-generation-sequencing (NGS) platforms. C. mesnili populations from different water reservoirs in the Czech Republic were sequenced at the first internal transcribed spacer (ITS1) of the ribosomal gene cluster, analysed with this new pipeline and compared with published results from the same populations but using cloning and Sanger sequencing method. I detected that relative frequencies of C. mesnili ITS1 sequence types were similar when compared to other sequencing methods, thereby validating the bioinformatic pipeline, and showing the suitability of 454 platform to perform population biology analyses. After this validation, in Chapter 3, I analysed the population dynamics and host-genotype specificity of C. mesnili, in long-term samples collected from a single lake, and based on the sequence variations in the ITS1 region. I found that the most abundant C. mesnili ITS1 sequence type decreased, while rare sequences increased over the course of the study (4 years). The observed pattern is consistent with the negative frequency-dependent selection. However, only a weak signal of host-genotype specificity between C. mesnili and Daphnia genotypes was detected, which supports the lack of host-genotype specificity in this system. Finally, in Chapter 4, I described the patterns of geographical population structure, intraspecific genetic variation, and recombination of two Daphnia-infecting microsporidia: Berwaldia schaefernai and the unknown microsporidium MIC1. These patterns were used to predict the existence of secondary hosts in the life cycle of these microsporidia. I observed little variation among B. schaefernai parasite strains infecting different host populations; in contrast, there was significant genetic variation among populations of MIC1. Additionally, ITS genetic diversity was lower in B. schaefernai than in MIC1. These findings suggest that the presumed secondary host for B. schaefernai is expected to be mobile, while in MIC1 the secondary host (if exists) does not appear to facilitate dispersal to the same degree. Finally, recombination analyses indicated cryptic sex in B. schaefernai and pure asexuality in MIC1. All these findings enable a more comprehensive understanding of the biology of Daphnia-infecting microparasites and the genetic basis of Daphnia-microparasites coevolution in natural populations

Inserción laboral en personas con daño cerebral: proyecto de intervención sociolaboral

El colectivo de personas que han sufrido una lesión cerebral es aun un gran desconocido hoy en día. la falta de apoyos y recursos por parte de las instituciones y la homogeneidad de las lesiones, no hay dos pacientes iguales, hacen que las posibilidades de insertarse en el mercado laboral una vez finalizados los procesos de rehabilitación,sean muy escasas. Con el fin de facilitar el acceso al empleo de este colectivo y mejorar así su calidad de vida, presento este proyecto, consistente en una primera fase de cualificación académica a traves de la impartición de un certificado de profesionalidad y un taller de habilidades laborales. La segunda fase consiste en la prospección de puestos de trabajo en el mercado ordinario y la propia inserción laboral a través de la metodología de "empleo con apoyo" la cual se dirige a todas discapacidades que por las condiciones de la misma resultan más complicadas de integrarse, generando así las mismas oportunidades de empleo al colectivo que al resto de la sociedad.Grado en Educación Socia

A hypothesis about the influence of oxidative stress on amino acid protein composition during evolution

Life emerged in an anoxic world, but the release of molecular oxygen, the by-product of photosynthesis, forced adaptive changes to counteract its toxicity. However, reactive oxygen species can damage all cellular components, including proteins. Therefore, several mechanisms have evolved to balance the intracellular redox state and maintain a reductive environment more compatible with many essential biological functions. In this study, we statistically interrogated the amino acid composition of E. coli proteins to investigate how the proneness or susceptibility to oxidation of amino acids biased their sequences. By sorting the proteins into five compartments (cytoplasm, internal membrane, periplasm, outer membrane, and extracellular), we found that various oxidative lesions constrain protein composition and depend on the cellular compartments, impacting the evenness of distribution or frequency. Our findings suggest that oxidative susceptibility could influence the observed differences in amino acid abundance across cellular compartments. This result reflects how the oxidative atmosphere could restrict protein amino acid composition and impose a codon bias trend

Comment on "Properties of the recovery phase of extreme storms" by Choraghe et al. (2021)

Choraghe et al. (2021), based on a study of the recovery phase of the SYM-H index of 31 extreme geomagnetic storms, have recently concluded that the hyperbolic decay function is only able to explain the complete recovery phase of about one third of events and that both the exponential or the hyperbolic decay functions fail to explain the late recovery phase of storms. Furthermore, they propose a linear function to model the late recovery phase and claim that the proposed model could throw new light on the relative importance of different physical processes involved during the complete recovery phase of extreme storms. We assert that the Choraghe et al. (2021) conclusions regarding the recovery phase of extreme storms analysis are incorrect and in particular are based on a misunderstanding of the nature of the evolution of the SYM-H index and the energy balance of the ring current

Estimation of the solar wind extreme events

This research provides an analysis of extreme events in the solar wind and in the magnetosphere due to disturbances of the solar wind. Extreme value theory has been applied to a 20-year data set from the Advanced Composition Explorer spacecraft for the period 1998–2017. The solar proton speed, solar proton temperature, solar proton density, and magnetic field have been analyzed to characterize extreme events in the solar wind. The solar wind electric field, vBz has been analyzed to characterize the impact from extreme disturbances in the solar wind to the magnetosphere. These extreme values were estimated for 1-in-40- and 1-in-80-year events, which represent two and four times the range of the original data set. The estimated values were verified in comparison with measured values of extreme events recorded in previous years. Finally, our research also suggests the presence of an upper boundary in the magnitudes under study.Ministerio de Economía y CompetitividadAgencia Estatal de Investigació

Forecasting intense geomagnetic activity using interplanetary magnetic field data

Southward interplanetary magnetic fields are considered traces of geoeffectiveness since they are a main agent of magnetic reconnection of solar wind and magnetosphere. The first part of this work revises the ability to forecast intense geomagnetic activity using different procedures available in the literature. The study shows that current methods do not succeed in making confident predictions. This fact led us to develop a new forecasting procedure, which provides trustworthy results in predicting large variations of Dst index over a sample of 10 years of observations and is based on the value Bz only. The proposed forecasting method appears as a worthy tool for space weather purposes because it is not affected by the lack of solar wind plasma data, which usually occurs during severe geomagnetic activity. Moreover, the results obtained guide us to provide a new interpretation of the physical mechanisms involved in the interaction between the solar wind and the magnetosphere using Faraday's law.Comisión Interministerial de Ciencia y Tecnología (CICYT

Programa sobre hábitos de alimentación saludables en la escuela a través del huerto ecológico

Esta propuesta didáctica en el aula supone la iniciación de los alumnos de Educación Primaria en las adecuadas prácticas alimenticias centrándose en un programa de intervención que los aproxime al conocimiento de los alimentos ecológicos, respetuosos con el medio ambiente y mediante los cuales llevarán a cabo una alimentación saludable y responsable. Este programa de intervención tiene como objeto establecer un huerto ecológico en el centro escolar que sirva como recurso didáctico. Es una propuesta interdisciplinar, ya que se trabaja desde varias áreas de conocimiento (ciencias naturales y c.sociales, educación física, lengua castellana, matemáticas, lengua extranjera...). Y en la que consideramos de gran importancia la colaboración de toda la comunidad educativa.Grado en Educación Primari

Comment on "Interplanetary conditions leading to superintense geomagnetic storms (dst ≤ -250 nt) during solar cycle 23" by E. Echer et al.

Comisión Interministerial de Ciencia y Tecnología-CICY