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205 result(s) for "Moya, Patricia"
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Unexpected associated microalgal diversity in the lichen Ramalina farinacea is uncovered by pyrosequencing analyses
The current literature reveals that the intrathalline coexistence of multiple microalgal taxa in lichens is more common than previously thought, and additional complexity is supported by the coexistence of bacteria and basidiomycete yeasts in lichen thalli. This replaces the old paradigm that lichen symbiosis occurs between a fungus and a single photobiont. The lichen Ramalina farinacea has proven to be a suitable model to study the multiplicity of microalgae in lichen thalli due to the constant coexistence of Trebouxia sp. TR9 and T. jamesii in long-distance populations. To date, studies involving phycobiont diversity within entire thalli are based on Sanger sequencing, but this method seems to underestimate the diversity. Here, we aim to analyze both the microalgal diversity and its community structure in a single thallus of the lichen R. farinacea by applying a 454 pyrosequencing approach coupled with a careful ad hoc-performed protocol for lichen sample processing prior to DNA extraction. To ascertain the reliability of the pyrosequencing results and the applied bioinformatics pipeline results, the thalli were divided into three sections (apical, middle and basal zones), and a mock community sample was used. The developed methodology allowed 40448 filtered algal reads to be obtained from a single lichen thallus, which encompassed 31 OTUs representative of different microalgae genera. In addition to corroborating the coexistence of the two Trebouxia sp. TR9 and T. jamesii taxa in the same thallus, this study showed a much higher microalgal diversity associated with the lichen. Along the thallus ramifications, we also detected variations in phycobiont distribution that might correlate with different microenvironmental conditions. These results highlight R. farinacea as a suitable material for studying microalgal diversity and further strengthen the concept of lichens as multispecies microecosystems. Future analyses will be relevant to ecophysiological and evolutionary studies to understand the roles of the multiple photobionts in lichen symbioses.
Trebouxia lynnae sp. nov. (Former Trebouxia sp. TR9): Biology and Biogeography of an Epitome Lichen Symbiotic Microalga
Two microalgal species, Trebouxia jamesii and Trebouxia sp. TR9, were detected as the main photobionts coexisting in the thalli of the lichen Ramalina farinacea. Trebouxia sp. TR9 emerged as a new taxon in lichen symbioses and was successfully isolated and propagated in in vitro culture and thoroughly investigated. Several years of research have confirmed the taxon Trebouxia sp. TR9 to be a model/reference organism for studying mycobiont–photobiont association patterns in lichen symbioses. Trebouxia sp. TR9 is the first symbiotic, lichen-forming microalga for which an exhaustive characterization of cellular ultrastructure, physiological traits, genetic and genomic diversity is available. The cellular ultrastructure was studied by light, electron and confocal microscopy; physiological traits were studied as responses to different abiotic stresses. The genetic diversity was previously analyzed at both the nuclear and organelle levels by using chloroplast, mitochondrial, and nuclear genome data, and a multiplicity of phylogenetic analyses were carried out to study its intraspecific diversity at a biogeographical level and its specificity association patterns with the mycobiont. Here, Trebouxia sp. TR9 is formally described by applying an integrative taxonomic approach and is presented to science as Trebouxia lynnae, in honor of Lynn Margulis, who was the primary modern proponent for the significance of symbiosis in evolution. The complete set of analyses that were carried out for its characterization is provided.
miR-146a regulates the crosstalk between intestinal epithelial cells, microbial components and inflammatory stimuli
Regulation of miR-146a abundance and its role in intestinal inflammation and particularly in intestinal epithelial cells (IECs) has been poorly studied. Here we study the relationship between bacterial antigens and inflammatory stimuli, and miR-146a expression using IEC lines and models of colitis (trinitrobenzenesulfonic acid (TNBS), dextran sulfate sodium (DSS) and the CD4 + CD62L + T cell transfer model). Specific bacterial antigens and cytokines (LPS, flagelin and IL-1β/TNF) stimulate miR-146a expression, while peptidoglycan, muramyldipeptide and CpG DNA have no effect. Overexpression of miR-146a by LPS depends on the activation of the TLR4/MyD88/NF-kB and Akt pathways. Accordingly, the induction of miR-146a is lower in TLR4, but not in TLR2 knock out mice in both basal and colitic conditions. miR-146a overexpression in IECs induces immune tolerance, inhibiting cytokine production (MCP-1 and GROα/IL-8) in response to LPS (IEC18) or IL-1β (Caco-2). Intestinal inflammation induced by chemical damage to the epithelium (DSS and TNBS models) induces miR-146a, but no effect is observed in the lymphocyte transfer model. Finally, we found that miR-146a expression is upregulated in purified IECs from villi vs. crypts. Our results indicate that miR-146a is a key molecule in the interaction among IECs, inflammatory stimuli and the microbiota.
Symbiotic microalgal diversity within lichenicolous lichens and crustose hosts on Iberian Peninsula gypsum biocrusts
This study analyses the interactions among crustose and lichenicolous lichens growing on gypsum biocrusts. The selected community was composed of Acarospora nodulosa , Acarospora placodiiformis , Diploschistes diacapsis , Rhizocarpon malenconianum and Diplotomma rivas-martinezii . These species represent an optimal system for investigating the strategies used to share phycobionts because Acarospora spp . are parasites of D. diacapsis during their first growth stages, while in mature stages, they can develop independently. R. malenconianum is an obligate lichenicolous lichen on D. diacapsis , and D. rivas-martinezii occurs physically close to D. diacapsis . Microalgal diversity was studied by Sanger sequencing and 454-pyrosequencing of the nrITS region, and the microalgae were characterized ultrastructurally. Mycobionts were studied by performing phylogenetic analyses. Mineralogical and macro- and micro-element patterns were analysed to evaluate their influence on the microalgal pool available in the substrate. The intrathalline coexistence of various microalgal lineages was confirmed in all mycobionts. D. diacapsis was confirmed as an algal donor, and the associated lichenicolous lichens acquired their phycobionts in two ways: maintenance of the hosts’ microalgae and algal switching. Fe and Sr were the most abundant microelements in the substrates but no significant relationship was found with the microalgal diversity. The range of associated phycobionts are influenced by thallus morphology.
Unravelling the Symbiotic Microalgal Diversity in Buellia zoharyi (Lichenized Ascomycota) from the Iberian Peninsula and Balearic Islands Using DNA Metabarcoding
Buellia zoharyi is a crustose placodioid lichen, usually occurring on biocrusts of semiarid ecosystems in circum-Mediterranean/Macaronesian areas. In previous work, we found that this lichenized fungus was flexible in its phycobiont choice in the Canary Islands. Here we test whether geography and habitat influence phycobiont diversity in populations of this lichen from the Iberian Peninsula and Balearic Islands using Sanger and high throughput sequencing (HTS). Additionally, three thallus section categories (central, middle and periphery) were analyzed to explore diversity of microalgal communities in each part. We found that B. zoharyi populations hosted at least three different Trebouxia spp., and this lichen can associate with distinct phycobiont strains in different habitats and geographic regions. This study also revealed that the Trebouxia composition of this lichen showed significant differences when comparing the Iberian Peninsula with the Balearics thalli. No support for differences in microalgal communities was found among thallus sections; however, several thalli showed different predominant Trebouxia spp. at each section. This result corroborate that thallus parts selected for DNA extraction in metabarcoding analyses are key to not bias the total phycobiont diversity detected. This study highlights that inclusion of HTS analysis is crucial to understand lichen symbiotic microalgal diversity.
Holistic Competencies and Employability: Diagnosis and Improvements for Higher Education in Ecuador from a Labor Market Perspective
Soft skills are increasingly recognised as decisive factors for employability and career advancement in the global labour market. This study examines their role in the professional trajectories of university graduates in Ecuador, analysing both the competencies supplied by higher education and the structural demand of the labour market. Based on institutional surveys applied to 3358 graduates from the Salesian Polytechnic University (Cuenca campus), the results show that more than 90% of graduates remain in operational positions, while only 5% reach tactical or managerial levels. To address this phenomenon, five key soft skills—leadership, effective communication, teamwork, problem-solving, and adaptability—were evaluated through a structured questionnaire using Likert-type items. The findings reveal a persistent concentration of professionals in lower organisational levels and heterogeneous perceptions of the applicability of academic training. These outcomes highlight both individual skill gaps and structural limitations of the Ecuadorian labour market, such as the scarcity of managerial positions and the prevalence of family-based business structures. In response, the study proposes a sector-based curricular improvement strategy that systematically incorporates soft skills into university programmes, differentiated by economic sectors such as education, health, commerce, public administration, industry, and primary activities. Grounded in empirical evidence, this approach provides a practical framework to enhance graduates’ career progression, foster more equitable professional mobility, and strengthen the relevance of higher education. The model can be replicated across other Latin American universities facing similar challenges, while also aligning with international standards for competency-based education.
Impact of IL6R genetic variants on treatment efficacy and toxicity response to sarilumab in rheumatoid arthritis
Background Sarilumab, an IL-6 receptor antagonist, is a first-line biologic disease-modifying anti-rheumatic drug for rheumatoid arthritis. The identification of genetic biomarkers as predictors of response to sarilumab could allow for a personalized treatment strategy to improve clinical outcomes. Methods We conducted a retrospective cohort study of 62 patients treated with sarilumab to determine whether single-nucleotide polymorphisms (SNP) in the IL6R gene could predict efficacy and toxicity responses. Six SNPs previously described in the IL6R gene (rs12083537, rs11265618, rs4329505, rs2228145, rs4537545, and rs4845625) were genotyped in DNA samples obtained from these patients. Using parametric tests, we evaluated the association between these polymorphisms and clinicopathological features. Treatment response was assessed six months after treatment initiation. Satisfactory response was based on EULAR criteria. Low disease activity was determined according to DAS28 and CDAI and quantitative improvements in DAS28 and CDAI scores. Results Three SNPs (rs4845625, rs4329505 and rs11265618) were significantly associated with response outcomes. All of the SNPs, except for rs12083537, had at least one significant association with dyslipidemia or hepatotoxicity. Conclusions These findings support the potential clinical value of SNPs, particularly rs4845625, as potentially useful biomarkers to predict response to sarilumab in patients with RA.
Multidisciplinary approach to describe Trebouxia diversity within lichenized fungi Buellia zoharyi from the Canary Islands
The Canary Islands are famous for their extraordinary biodiversity; however, lichenized algae have only been studied partially. Buellia zoharyi is a circum-Mediterranean/Macaronesian species that usually occurs in semi-arid areas of the Mediterranean, but occasionally some interesting communities of this species grow on basaltic lava flows in Lanzarote, Fuerteventura and Tenerife. Those three locations showed similar ecological conditions, but different mean annual temperatures. Here we applied a multidisciplinary approach to describe microalgae diversity from B. zoharyi covering the entire described range of distribution in the Canary Islands. Photobionts were characterized in symbiosis using molecular and microscopic techniques. Different Trebouxia spp. were detected as primary photobiont in each island ( Trebouxia cretacea -Fuerteventura, T. asymmetrica -Lanzarote and Trebouxia sp. ` arnoldoi ´-Tenerife). Coexistence of various Trebouxia spp. within a thallus were detected by using specific primers-PCR. Those three photobionts were isolated and cultured under laboratory conditions. Different phytohormone profiles were obtained in the isolated strains which suggest different internal signalling needs. In addition, we characterized the response of the isolated strains to different temperatures using chlorophyll fluorescence. T. asymmetrica did not modify their F v /fm values with respect to temperature acclimation. In contrast, Trebouxia sp. `arnoldoi’ and T. cretacea were more sensitive to changes in growing temperature decreasing Fv/fm at 17 °C. Our results indicate that B. zoharyi is flexible regarding the photobiont choice depending on the region, and suggest that bioclimatic factors could influence the myco/photobiont association patterns.
Phylogeography of Ramalina farinacea (Lichenized Fungi, Ascomycota) in the Mediterranean Basin, Europe, and Macaronesia
Ramalina farinacea is an epiphytic lichen-forming fungus with a broad geographic distribution, especially in the Northern Hemisphere. In the eighties of the last century, it was hypothesized that R. farinacea had originated in the Macaronesian–Mediterranean region, with the Canary Islands as its probable southernmost limit, and thereafter it would have increased its distribution area. In order to explore the phylogeography of this emblematic lichen, we analyzed 120 thalli of R. farinacea collected in 38 localities distributed in temperate and boreal Europe, the Western Mediterranean Basin, and several Macaronesian archipelagos in the Atlantic Ocean. Data from two nuclear markers (nrITS and uid70) of the mycobiont were obtained to calculate genetic diversity indices to infer the phylogenies and haplotype networks and to investigate population structure. In addition, dating analysis was conducted to provide a valuable hypothesis of the timing of the origin and diversification of R. farinacea and its close allies. Our results highlight that phylogenetic species circumscription in the “Ramalina farinacea group” is complex and suggests that incomplete lineage sorting is at the base of conflicting phylogenetic signals. The existence of a high number of haplotypes restricted to the Macaronesian region, together with the diversification of R. farinacea in the Pleistocene, suggests that this species and its closest relatives originated during relatively recent geological times and then expanded its range to higher latitudes. However, our data cannot rule out whether the species originated from the Macaronesian archipelagos exclusively or also from the Mediterranean Basin. In conclusion, the present work provides a valuable biogeographical hypothesis for disentangling the evolution of this epiphytic lichen in space and time.
Increase of Circulating Monocyte–Platelet Conjugates in Rheumatoid Arthritis Responders to IL-6 Blockage
Platelets (PLT) bind to a significant percentage of circulating monocytes and this immunomodulatory interaction is increased in several inflammatory and autoimmune conditions. The therapeutic blockage of IL-6 with Tocilizumab (TCZ) alters PLT and the phenotype and function of monocytes in rheumatoid arthritis (RA). However, the relationship between monocyte–PLT conjugates (CD14+PLT+) and clinical and immunological variables and the regulation of this interaction by IL-6 blockage are still unknown. Here, we compared the presence of monocyte–PLT conjugates (CD14+PLT+) and membrane CD162 expression using flow cytometry, and, by ELISA, the markers of PLT activation (sCD62P and sCD40L) in healthy donors (HD) and patients with long-standing RA before TCZ (baseline). We found higher percentages and absolute counts of CD14+PLT+, and higher plasmatic levels of sCD62P and sCD40L but lower CD162 expression on monocytes from RA patients than those from HD. Additionally, the levels of CD14+PLT+ inversely correlated with inflammatory parameters. Interestingly, 95% of patients with lower percentages of CD14+PLT+ and only 63% of patients with higher percentages of CD14+PLT+ achieved a EULAR-defined response at four weeks (p = 0.036). After TCZ, the percentage of CD14+PLT+ increased in 92% of RA patients who achieved 12 w-remission (p < 0.001). Our results suggest that the binding of PLTs has a modulatory effect, accentuated by the increased binding of PLTs to monocytes in response to the therapeutic blockage of IL-6.