Ocean acidification exacerbates the effect of UV radiation on the calcifying phytoplankter Emiliania huxleyi

Increasing atmospheric CO2 concentration affects calcification in most planktonic calcifiers. Both reduced or stimulated calcification under high CO2 have been reported in the widespread coccolithophore Emiliania huxleyi. This might affect the response of cells to photosynthetically active radiation ( PAR; 400-700 nm) and ultraviolet radiation (UVR; 280-400 nm) by altering the thickness of the coccolith layer. Here we show that in the absence of UVR, the calcification rates in E. huxleyi decrease under lowered pH levels (pH(NBS) of 7.9 and 7.6; pCO(2) of 81 and 178 Pa or 804 and 1759 ppmv, respectively) leading to thinned coccolith layers, whereas photosynthetic carbon fixation was slightly enhanced at pH 7.9 but remained unaffected at pH 7.6. Exposure to UVR (UV-A 19.5 W m(-2), UV-B 0.67 W m(-2)) in addition to PAR (88.5 W m(-2)), however, results in significant inhibition of both photosynthesis and calcification, and these rates are further inhibited with increasing acidification. The combined effects of UVR and seawater acidification resulted in the inhibition of calcification rates by 96% and 99% and that of photosynthesis by 6% and 15%, at pH 7.9 and 7.6, respectively. This differential inhibition of calcification and photosynthesis leads to significant reduction of the ratio of calcification to photosynthesis. Seawater acidification enhanced the transmission of harmful UVR by about 26% through a reduction of the coccolith layer of 31%. Our data indicate that the effect of a high-CO2 and low-pH ocean on E. huxleyi ( because of reduced calcification associated with changes in the carbonate system) enhances the detrimental effects of UVR on the main pelagic calcifier.National Basic Research Program of China [2009CB421207]; National Natural Science Foundation of China [40676063, 40876058]; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET, Argentina) ; Shantou University and by the European Project on Ocean Acidification (EPOCA), through the European Community's 7th Framework Programme [211384

Spatial and temporal features of neutrophils in homeostasis from the perspective of computational biology

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de Lectura: 22-07-2022Neutrophils are myeloid cells that originate in the Bone Marrow and enter circulation to patrol for infectious agents. An important part of the “nonspecific” immune system consists on Neutrophils infiltrating challenged tissues, and the established belief was that they stay away from steady-state organs to avoid the risk of exposing them to their cytotoxic content. In the papers presented in this thesis, we show that neutrophils can in fact be found in almost all tissues under homeostasis. We further present proof that they undergo shifts in DNA accessibility, RNA expression and protein content in the infiltrated tissues. Using functional annotation we predict distinct roles depending on the tissue. While in hematopoietic organs the transcriptomic signatures of neutrophils align with canonical functions like immune response and migration, in other tissues such as the skin we find non-canonical functions i.e, epithelial and connective tissue growth or pro-angiogenic roles in the gut and the lung. This predicted pro-angiogenic role was indeed confirmed for the lung. We finally describe that infiltration in tissues follows circadian dynamics, and that once it has occurred, neutrophils experience changes in transcription depending on the time of the day. The analyses of circadian rhythms on mammalian models are often hindered by the inherent difficulty of performing exhaustive sampling (i.e.: every hour for at least 48h). Hence, I implemented CircaN as an R package, which outperforms existing tools in most scenarios. To provide the most complete analysis possible, we provide a full mode analysis option, in which we run CircaN and the two most used algorithms and provide integrated results. We present proof-of-concept results showing that combining various tools yields the best true positive to false positive ratio for most purposesEsta Tesis ha sido financiada por el Ministerio de Ciencia, Innovación y Universidades (MICINN

LAMINARIOCOLAX SP (PHAEOPHYCEAE) ASSOCIATED WITH GALL DEVELOPMENTS IN LESSONIA NIGRESCENS (PHAEOPHYCEAE)1

of gall development on this alga, identified the possible causal agent, and assessed the extent of the phenomenon in two wild stands of the host. Our results showed that galls affecting natural populations of L. nigrescens were associated with the infection by a filamentous brown algal endophyte of the genus Laminariocolax. Assignment to Laminariocolax of the endophytes isolated from cultured gall tissue was based on the (i) high internal transcribed spacer 1 (ITS1) sequence similarity and phylogenetic relationship between the Chilean isolates and several species of the genus Laminariocolax endophytic in other kelps, (ii) reproductive and vegetative features of the endophyte in culture, and (iii) anatomical agreement of fully developed galls of Lessonia with those described for other kelp galls caused by endophytic members of Laminariocolax. Unequivocal identification at the species level of the endophytes infecting Lessonia, however, awaits further studies.Ministry of Science and Technology, National Natural Science Foundation of China [90411018]; Science Foundation of Changshu Institute of Technology [KY11707

Formaciones imaginarias del diseñador gráfico en el discurso del campo académico.

En este trabajo se describe un proyecto de tesis doctoral en el que se analiza el discurso sobre el diseñador gráfico. Se parte del supuesto de que existe una tricotomía de su perfil: 1) el campo profesional, 2) el campo educativo y, 3) el campo académico. Proponemos que dicha tricotomía permite la identificación de imaginarios sobre el tema, y no solo eso, sino que también aporta elementos que conforman la identidad (Bauman, 2002) de un diseñador gráfico. La pregunta de investigación es ¿Cuál es la identidad discursiva del diseñador gráfico en el campo académico? La investigación descrita es de tipo cualitativo y deductivo; para la construcción la identidad discursiva (Van Dijk, T; 2008) del diseñador gráfico, se toman en cuenta diversas publicaciones: principalmente investigaciones y breves artículos difundidos en comunidades/foros de reflexión y debate en torno a la temática, además de memorias de congresos y libros. En apoyo al desarrollo del proyecto se ha diseñado un Laboratorio de Intervención en el Diseño, cuyos objetivos son impulsar el desarrollo social y cultural de los diseñadores gráficos por medio de la investigación, educación continua, producción y vinculación. En un primer acercamiento a las formaciones imaginarias (Pêcheux, 1978) sobre la identidad del diseñador gráfico se centran en el grado de erudición para la ejecución de su trabajo, en la cultura que demuestran y en la autonomía con la que producen

UV-absorbing compounds in Porphyra haitanensis (Rhodophyta) with special reference to effects of desiccation

The intertidal red alga Porphyra haitanensis Chang et Zheng is episodically desiccated and exposed to high levels of solar radiation at low tide during emersion. However, little has been documented on the relationship between the stresses during desiccation and related chemical compounds. We found that P. haitanensis thalli, when desiccated under indoor (artificial radiation) or outdoor (solar radiation) conditions, with or without UV radiation (UVR: 280-400 nm), contained significantly higher concentrations of UV-absorbing compounds (peak at 336 nm) than those maintained submerged (without desiccation). Solar UVR had no effect on the content of UV-absorbing compounds. Even though the concentration of these compounds decreased with time in all treatments, a slower decrease was observed in the desiccated samples. The samples with higher levels of UV-absorbing compounds showed higher photochemical efficiency of photosystem II (PS II) during the exposure or subsequent recovering process than samples with low concentration of UV-absorbing compounds, reflecting their protective role. The concentration of these compounds varied in different parts of the thallus, with the middle and marginal parts containing 60-80% more UV-absorbing compounds than the basal parts in both female and male plants. In addition, the marginal parts of male thalli contained more UV-absorbing compounds than the corresponding parts of female thalli. Our data suggest that desiccation plays a key role in this alga to maintain high concentration of UV-absorbing compounds, and that this might provide a beneficial advantage to compete in the intertidal zone where the organism is normally exposed to high levels of UVR