Works presented

Summary
Tradescantia fluminensis is an invasive exotic plant that affects the native biodiversity of riparian forests. However, its long-term effect on European ecosystems remains unknown. The objective of this study was to assess the impact of T. fluminensis on the seed bank of the native flora in a riparian forest in Galicia, analyzing whether this impact varies depending on the depth of the seed bank in the soil, light exposure, or the invasion status. To achieve this, the seedling emergence method was used. Soil samples were collected from areas invaded by T. fluminensis and non-invaded areas (adjacent zones) at ten points along the banks of the Tins River (Outes, A Coruña) at two different depths (0 a 5 cm; 5 a 10 cm). The soils were placed in pots, combining them into two treatments (light and shade), and maintained in a greenhouse for six months, with weekly monitoring of seedling emergence. To evaluate their growth and development, two harvests were conducted (at months three and six), in which various ecophysiological parameters of the species were measured. The results indicated that various plant species were able to establish themselves in both invaded and non-invaded soils, without significant quantitative differences in species richness and abundance. However, there were qualitative differences, as invaded areas were characterized by a higher establishment of exotic species such as Oxalis corniculata and Phytolacca americana. Additionally, it was observed that the shading caused by the invasive species, which limits light reaching the soil, has a severe negative impact on the germination and establishment of species present in the seed bank. In light of these findings, for a future restoration plan based on the area's seed bank, it is recommended to remove T. fluminensis to eliminate the shading effect and to implement rigorous monitoring of germinating and establishing species, eradicating those that could become problematic to prevent new secondary invasions.

Direction
RETUERTO FRANCO, JOSE CARLOS RUBÉN (Tutorships)
VARELA RIO, ZULEMA (Co-tutorships)
Rodríguez Parra, Jonatan (Co-tutorships)

Court
COBO GRADIN, FERNANDO (Chairman)
PONTEVEDRA POMBAL, FRANCISCO XABIER (Secretary)
ABOAL VIÑAS, JESUS RAMON (Member)

Summary
Anisakis simplex is a parasite that can be present in many fish products and that can accidentally cause pathologies in humans by consuming these products, raw or undercooked, when they contain larvae of the parasite in its infective phase. These infective larvae can appear in many species of fish and cephalopods of commercial interest that constitute an important part of the human diet, especially in some countries. To reduce and prevent this public health problem, awareness plans for the population and strategies and recommendations on techniques for capturing, handling and processing fish products, their conservation and consumption have been developed. This work presents the public health problems caused by the parasite Anisakis simplex and explains some of the techniques and processes recommended at different levels of the fishery-food industry and in the domestic sphere to prevent infection by Anisakis in the most effective way.

Direction
IGLESIAS PIÑEIRO, FRANCISCO JAVIER (Tutorships)

Court
COBO GRADIN, FERNANDO (Chairman)
PONTEVEDRA POMBAL, FRANCISCO XABIER (Secretary)
ABOAL VIÑAS, JESUS RAMON (Member)

Summary
The preventive conservation towards the biodeterioration produced by the biofilms that develop in monuments made of granite is a priority in the galician background because the inexorable nature of the biological colonization due to weather characteristics. This study analyzes the potential biocidal and biostatic effects on phototrophic communities through the application of metallic nanoparticles on granite surfaces. Laboratory experiments were designed to test silver (Ag) nanoparticles, titanium dioxide, and a mixture of various metals at different concentrations, applied directly to a biofilm inoculum to assess their biocidal and biostatic effects. The results showed that, for phototrophic communities, the tested nanoparticles do not exhibit a biocidal effect but showed a biostatic effect. Specifically, Ag nanoparticles (250 ppm) and the metal mixture (750 ppm) suppressed biofilm development on agar surfaces, while TiO2 nanoparticles slowed biofilm growth on granite surfaces. Nevertheless, further long-term experiments conducted in outdoor environments are necessary.

Direction
PRIETO LAMAS, BEATRIZ LORETO (Tutorships)
PEREZ VELON, DIANA (Co-tutorships)

Court
COBO GRADIN, FERNANDO (Chairman)
PONTEVEDRA POMBAL, FRANCISCO XABIER (Secretary)
ABOAL VIÑAS, JESUS RAMON (Member)

Summary
The ban on the use of agrochemicals in the EU and the need to use more sustainable alternatives in crop protection has renewed interest in traditional methods for pathogen control. Among them is the use of crushed brassicas (biofumigation), the covering of the ground with plastics (solarization) or the combination of both techniques (biosolarization). Amending with brassicas represents a contribution of organic matter that helps to improve the physical and chemical conditions of the soil and, therefore, to increase the yield of the crops. In addition, brassicas produce chemical substances (glucosinolates) which, when broken down, form isothiocyanates, with antimicrobial activity. This antimicrobial activity could have positive effects on crops ( in quality and fruit production, for example) by exercising control over soil pathogens. However, few is still known about the effects of this technique on the biotic and physicochemical conditions of the soil, particularly in the cultivation of pepper, a horticultural species of particular importance in Galicia. The aim of this work is to determine the effect of the use of brassicas as biofumigants on the biotic and abiotic characteristics of the soil in pepper crops. The results show a positive effect of both biofumigation and biosolarization treatments on many of the soil variables studied, while solarization by itself does not significantly differ from the control. Pepper cultivation seems to take effective advantage of the improvements in soil conditions brought about by biofumigation and biosolarization, since at the time of harvest many of the effects on the studied variables are softened or disappeared. Although soil DNA content did not vary with the addition of brassicas, further study is needed to determine whether there are changes in the composition and functionality of soil microbial communities.

Direction
RETUERTO FRANCO, JOSE CARLOS RUBÉN (Tutorships)
LEMA MARQUEZ, MARGARITA (Co-tutorships)

Court
COBO GRADIN, FERNANDO (Chairman)
PONTEVEDRA POMBAL, FRANCISCO XABIER (Secretary)
ABOAL VIÑAS, JESUS RAMON (Member)

Summary
In this work, we have characterized how the response to different antitumor treatments is limited in efficacy by the metabolic state of the tumor cell, specifically, the A549 lung adenocarcinoma cell line. We have analyzed three drugs, two in routine clinical use, cisplatin and doxorubicin, and a new molecule under development, Ag5. The mechanism of Ag5 is based on the selective oxidation of cysteine thiols of the antioxidant system at the mitochondrial level triggering apoptosis. On the other hand, cisplatin (CDDP) and doxorrubicin (DOX) act at the DNA level, interfering with DNA repair mechanisms, causing DNA damage, and subsequently inducing apoptosis in cancer cells. By combining the metabolic reorganization caused by hypoxia with the use of other agents that affect intracellular redox homeostasis, we have measured the different responses in the same cell to the same drug. We believe that the clinical translation of the results is immediate since it should serve to establish the rationality of combinatorial therapies that take into account the phenotypic heterogeneity of the tumors.

Direction
DOMINGUEZ PUENTE, FERNANDO (Tutorships)
Domínguez Loidi, Blanca (Co-tutorships)

Court
POMBO RAMOS, CELIA MARIA (Chairman)
VILAS PETEIRO, ROMAN (Secretary)
ADRIO FONDEVILA, MARIA FATIMA (Member)

Summary
The pituitary gland is an endocrine organ whose main function is hormone secretion. It has the adenohypophysis, made up of different endocrine cells, and the neurohypophysis, which contains nerve endings from the hypothalamus. In 2009, the niche of adult stem cells in the pituitary was discovered. Due to the need to study the compartment of this population under the physiological changes of the gland at different times of life, the need was raised to obtain a labeling technique for said population to be used in cell tracking and differentiation studies. With this objective, we try to standardize a protocol based on the use of viral vectors with expression of GFP as a reporter gene in pituitary stem cells. To do this, a stem cell purification protocol was used, thanks to the characteristic expression of GFRA2 and purification with antibodies conjugated with magnetic particles. On these cells, different infection protocols with adenoviral or adeno-associated vectors were compared, selecting the one with the best infection efficiency as valid. Through the use of complementary techniques, the correct purification of the stem cell population was validated, as well as the monitoring of its in vitro culture and the efficacy of the different infection protocols on primary cells in suspension. As a result, an infection protocol using adeno-associated viruses on primary cells in suspension was developed, providing a new tool for studying this population in the pituitary.

Direction
Alvarez Villamarin, Clara (Tutorships)
CHENLO MIRANDA, MIGUEL ANGEL (Co-tutorships)

Court
MOREIRA VILAR, MARIA TERESA (Chairman)
Woodhoo , Ashwin (Secretary)
TOVAR CARRO, SULAY AMPARO (Member)

Summary
Red blood cells have been traditionally considered simple oxygen carriers. Recent studies, some conducted in our laboratory, have revealed their role in various biological processes, including their potential involvement in tumor progression. In this context, extracellular vesicles derived from red blood cells have emerged as a potential key element in cell communication due to their ability to transport molecules. However, the interaction between red blood cells and tumor cells, as well as their impact on metastasis, has been barely explored. This study hypothesizes that extracellular vesicles derived from red blood cells play a key role in the tumor microenvironment as molecular carriers, impacting both tumor cells and immune system cells. The main objectives were to establish an efficient protocol for obtaining extracellular vesicles, analyze the effects of external factors on the morphology and function of red blood cells and determine whether red blood cells and/or extracellular vesicles participate in molecular transport. To achieve this, two protocols were compared, revealing that the passive release protocol favoured the production of small extracellular vesicles. Blood samples from breast cancer patients and healthy donors were incubated with red blood cells. Subsequently, flow cytometry and adhesion assays confirmed that red blood cells undergo modifications and, in turn, influence their surroundings. Finally, a co-culture assay with tumor cells and red blood cells was performed, both with and without direct contact using a Transwell system, demonstrating that molecular transport occurs in both conditions. These findings highlight the importance of red blood cells and their extracellular vesicles in tumor progression, suggesting their potential application as biomarkers or therapeutic tools in oncology.

Direction
VIDAL FIGUEROA, ANXO (Tutorships)
Costa Nogueira, Clotilde (Co-tutorships)

Court
MOREIRA VILAR, MARIA TERESA (Chairman)
Woodhoo , Ashwin (Secretary)
TOVAR CARRO, SULAY AMPARO (Member)

Summary
The central nervous system (CNS) has the ability to reorganize itself based on experiences or injuries, it is what we know as cerebral plasticity. Myelin, which envelops the neural axons and determines its rate of transmission, has been described as highly plastic, although the mechanisms regulating it are not known precisely. In this work we studied whether a peripheral lesion can induce, in the short term, changes in myelinization of central circuits at whole-brain scale in expression of myelin basic protein in cortical projections by surgically damaging the nerve pathways of whiskers in adult mice. The study was conducted with the tissue clarification technique iDISCO+, light sheet microscopy (lightsheet microscopy) and bioinformatic data analysis tools such as ClearMap or Imaris. With these techniques we were able to rule out the existence of myelin remodeling in the short term after the injury of the whiskers in adult mice.

Direction
VIEITES PRADO, ALBA (Tutorships)

Court
POMBO RAMOS, CELIA MARIA (Chairman)
VILAS PETEIRO, ROMAN (Secretary)
ADRIO FONDEVILA, MARIA FATIMA (Member)

Summary
The Galician rías are special ecosystems, rich in biodiversity and of high socioeconomic value, but they are exposed to pollution caused by anthropogenic activities. A representative case of this problem is the high concentration of lead in the sediments near the porcelain factory “Alfares de Ponte Sampaio,” located inside the Ría de Vigo. This study investigates the relationship between this lead contamination and the presence of diatoms with deformities in the area, also evaluating the severity of these deformities and their potential effects on biodiversity reduction. The hypothesis proposed is that a higher lead content increases the abundance and severity of deformities in diatom frustules and reduces the diversity of their communities. To test this, sediment samples were collected from different locations and depths near the former factory. The diatoms present were identified and analyzed under a microscope, and statistical tests were applied to correlate their deformities and biodiversity with lead levels. The results show that the abundance of deformed diatoms exceeds the expected threshold under non-stress conditions, but no significant correlations were found between lead concentration and the presence or severity of deformities. However, a trend of decreasing biodiversity with increasing metal concentration was observed, although it did not reach statistical significance. This study contributes to a better understanding of the effects that heavy metals can have on diatoms and highlights the need to consider other environmental factors in such research.

Direction
LEIRA CAMPOS, ANTON MANOEL (Tutorships)

Court
COBO GRADIN, FERNANDO (Chairman)
PONTEVEDRA POMBAL, FRANCISCO XABIER (Secretary)
ABOAL VIÑAS, JESUS RAMON (Member)