Synergistic effects of UVR and simulated stratification on commensalistic phytoplankton–bacteria relationship in two optically contrasting oligotrophic Mediterranean lakes

An indirect effect of global warming is a reduction in the depth of the upper mixed layer (UML) causing organisms to be exposed to higher levels of ultraviolet (UVR, 280–400 nm) and photosynthetically active radiation (PAR, 400–700 nm). This can affect primary and bacterial production as well as the commensalistic phytoplankton–bacteria relationship. The combined effects of UVR and reduction in the depth of the UML were assessed on variables related to the metabolism of phytoplankton and bacteria, during in situ experiments performed with natural pico- and nanoplankton communities from two oligotrophic lakes with contrasting UVR transparency (high-UVR versus low-UVR waters) of southern Spain. The negative UVR effects on epilimnetic primary production (PP) and on heterotrophic bacterial production (HBP), intensified under increased stratification, were higher in the low-UVR than in the high-UVR lake, and stronger on the phytoplanktonic than on the heterotrophic bacterial communities. Under UVR and increased stratification, the commensalistic phytoplankton–bacteria relationship was strengthened in the high-UVR lake where excretion of organic carbon (EOC) rates exceeded the bacterial carbon demand (BCD; i.e., BCD : EOC(%) ratio 100). The greater UVR damage to phytoplankton and bacteria and the weakening of their commensalistic interaction found in the low-UVR lake indicates that these ecosystems would be especially vulnerable to UVR and increased stratification as stressors related to global climate change. Thus, our findings may have important implications for the carbon cycle in oligotrophic lakes of the Mediterranean region.This study was supported by the Ministerio Español de Medio Ambiente, Rural y Marino (PN2009/067), Ciencia e Innovación (CGL2011-23681), Junta de Andalucía (Excelencia CVI-02598 and P09-RNM-5376), Consejo Nacional de Investigaciones Científicas y Técnicas – CONICET (PIP no. 112-201001-00228), and Fundación Playa Unión. G. Herrera and C. Durán were supported by a Formación de Profesorado Universitario grant from the Spanish government. The authors are indebted to the staff of Sierra Nevada National Park and Lagunas de Ruidera Natural Park for permission to work, to E. Jiménez-Coll for the bacterial production analysis, and to D. Nesbitt for writing assistance in English

Berezin Quantization of Gauged WZW and Coset Models

Gauged WZW and coset models are known to be useful to prove holomorphic factorization of the partition function of WZW and coset models. In this note we show that these gauged models can be also important to quantize the theory in the context of the Berezin formalism. For gauged coset models Berezin quantization procedure also admits a further holomorphic factorization in the complex structure of the moduli space.Comment: 15+1 pages, no figures, revte

Interactive effects of vertical mixing, nutrients and ultraviolet radiation: in situ photosynthetic responses of phytoplankton from high mountain lakes in Southern Europe

Global change, together with human activities, has resulted in increasing amounts of organic material (including nutrients) that water bodies receive. This input further attenuates the penetration of solar radiation, leading to the view that opaque lakes are more "protected" from solar ultraviolet radiation (UVR) than clear ones. Vertical mixing, however, complicates this view as cells are exposed to fluctuating radiation regimes, for which the effects have, in general, been neglected. Furthermore, the combined impacts of mixing, together with those of UVR and nutrient inputs are virtually unknown. In this study, we carried out complex in situ experiments in three high mountain lakes of Spain (Lake Enol in the National Park Picos de Europa, Asturias, and lakes Las Yeguas and La Caldera in the National Park Sierra Nevada, Granada), used as model ecosystems to evaluate the joint impact of these climate change variables. The main goal of this study was to address the question of how short-term pulses of nutrient inputs, together with vertical mixing and increased UVR fluxes modify the photosynthetic responses of phytoplankton. The experimentation consisted in all possible combinations of the following treatments: (a) solar radiation: UVR + PAR (280–700 nm) versus PAR (photosynthetically active radiation) alone (400–700 nm); (b) nutrient addition (phosphorus (P) and nitrogen (N)): ambient versus addition (P to reach to a final concentration of 30 μg P L−1, and N to reach N:P molar ratio of 31); and (c) mixing: mixed (one rotation from surface to 3 m depth (speed of 1 m 4 min−1, total of 10 cycles)) versus static. Our findings suggest that under ambient nutrient conditions there is a synergistic effect between vertical mixing and UVR, increasing phytoplankton photosynthetic inhibition and excretion of organic carbon (EOC) from opaque lakes as compared to algae that received constant mean irradiance within the epilimnion. The opposite occurs in clear lakes where antagonistic effects were determined, with mixing partially counteracting the negative effects of UVR. Nutrient input, mimicking atmospheric pulses from Saharan dust, reversed this effect and clear lakes became more inhibited during mixing, while opaque lakes benefited from the fluctuating irradiance regime. These climate change related scenarios of nutrient input and increased mixing, would not only affect photosynthesis and production in lakes, but might also further influence the microbial loop and trophic interactions via enhanced EOC under fluctuating UVR exposure.This work was supported by Ministerio Español de Medio Ambiente, Rural y Marino (PN2009/067) and Ciencia e Innovación (GLC2008-01127/BOS and CGL2011-23681), Junta de Andalucía (Excelencia CVI-02598), Agencia Nacional de Promoción Científica y Tecnológica (PICT 2007-1651) and Fundación Playa Unión; GH and CD were supported by the Spanish Government – Formación de Profesorado Universitario Grant

The influence of the 5 '-terminal nucleotide on AgoshRNA activity and biogenesis: importance of the polymerase III transcription initiation site

Recent evidence indicates that shRNAs with a relatively short basepaired stem do not require Dicer processing, but instead are processed by the Argonaute 2 protein (Ago2). We named these molecules AgoshRNAs as both their processing and silencing function are mediated by Ago2. This alternative processing yields only a single RNA guide strand, which can avoid off-target effects induced by the passenger strand of regular shRNAs. It is important to understand this alternative processing route in mechanistic detail such that one can design improved RNA reagents. We verified that AgoshRNAs trigger site-specific cleavage of a complementary mRNA. Second, we document the importance of the identity of the 5΄-terminal nucleotide and its basepairing status for AgoshRNA activity. AgoshRNA activity is significantly reduced or even abrogated with C or U at the 5΄-terminal and is enhanced by introduction of a bottom mismatch and 5΄-terminal nucleotide A or G. The 5΄-terminal RNA nucleotide also represents the +1 position of the transcriptional promoter in the DNA, thus further complicating the analysis. Indeed, we report that +1 modification affects the transcriptional efficiency and accuracy of start site selection, with A or G as optimal nucleotide. These combined results allow us to propose general rules for the design and expression of potent AgoshRNA molecule

Gamma Ray Bursts: Observations and Theoretical Conjectures

Gamma Ray Bursts (GRBs) are short bursts of very high energy photons which were discovered in the late 1960s. Ever since their discovery, scientists have wondered about their origin. Nowadays it is known that they originate outside the Milky Way because of their high red shift rst measured in the afterglows thanks to the Beppo-SAX satellite and ground-based observations. However, theoreticians still do not agree about the mechanism that generates the bursts, and different competing models are animatedly debated. Current GRB experiments include the Swift satellite and the Pierre Auger Observatory that could detect GRBs with an increase of the background. A forthcoming dedicated experiment is GLAST, a satellite observatory for detecting gamma rays with energies up to 300 GeV, whose launch is scheduled for early 2008

Detection and analysis of tumour biomarkers to strengthen the diagnosis of acute and chronic leukaemias

AbstractMolecular markers in leukaemia are essential to diagnose, establish prognosis factors and determine the correct treatment of patients; therefore, it is imperative to include molecular biology studies, so that, combined with cytomorphology and immunophenotyping studies, they constitute the differential diagnosis of these neoplasias. It is extremely important to implement a panel of molecular markers that allows us to detect oncogenes derived from chromosomal translocations, genes derived from epigenetic alterations and drug-resistant genes.A panel of molecular markers that included 11 genes derived from chromosomal translocations BCR-ABL major and minor breakpoints, E2A-PBX1, MLL-AF4, TEL-AML1, PML-RARα, AML1-ETO was standardised; cancer testis antigens (CTA) derived from NY-ESO1 and MAGE-A3 epigenetic alterations and multi-drug-resistant genes ABCB1 and ABCG2. 30 patients diagnosed with leukaemia from Mexico's General Hospital (Hospital General de Mexico) were included. They suffered from acute lymphoblastic leukaemia (ALL) and acute myeloblastic leukaemia (AML); bone marrow mononuclear cells were used, from which RNA was extracted for the synthesis of cDNA and RT-PCR for each of the markers. In acute lymphoblastic leukaemia (ALL), BCR-ABL biomarkers expressed under 30% (3/10), E2A-PBX1 10% (1/10), ABC-B1 80% (8/10), and ABC-G2 60% (6/10). Patients with acute myeloblastic leukaemia (AML) expressed 30% PML-RARα (3/10), 40% ABC-B1 (4/10), and 10% ABC-G2 (1/10). Lastly, in patients with chronic myeloid leukaemia (CML), BCR-ABL was over 100% (10/10), ABC-B1 20% (2/10), and ABC-G2 50% (5/10). The presence of transcripts from chimeric genes minor BCR-ABL and E2A-PBX1 in ALL; PML-RARα in AML; and major BCR-ABL in CML, confirms the importance that the panel of molecular markers has in strengthening the diagnosis and prognosis of these conditions

Normal aortic diameters within the Mexican population and the impact of gender and ethnicity

Background: There is a lack of studies describing the normal size of the aorta in Mexican population. Objective: To analyze aortic measurements in Mexican patients and to compared them with patients from five different countries. Methods: Measurements of the aorta were divided in Mexicans and controls. Comparisons between ethnicities and groups were performed using Mann Whitney rank sum test. Results: The registry included 166 patients, 106 (63.8%) were enrolled in Mexico and 60 (36.1%) in the control group. Mexican patients had smaller aortic diameters compared to the control group, at the level of the right renal artery ostium, inferior mesenteric artery, and aortic bifurcation. The Hispanic population had significantly smaller aortic diameters from the level of the celiac artery to the aortic bifurcation. Conclusion: The normal aortic diameters in the Mexican population are smaller compared to other countries.</p

Reflexiones universitarias. San Pedro Valencia: renovación urbana, saneamiento ambiental y emprendimientos turísticos. Otoño 2015

Los trabajos que aquí se presentan se elaboraron por las y los estudiantes como parte de las actividades del Proyecto de Aplicación Profesional (PAP) “San Pedro Valencia: renovación urbana, saneamiento ambiental y emprendimientos turísticos”, durante el periodo de Otoño de 2015. A lo largo del periodo los autores compartieron sus reflexiones en torno a su percepción sobre el contexto en el que actúa el PAP; sobre las alternativas posibles a la problemática detectada y lo que significa pensar una alternativa; sobre los sujetos con los que se ha interactuado a lo largo de la experiencia de trabajo y sobre el papel del profesionista y del ciudadano en un mundo como el que nos tocó vivir. La obra está compuesta por reflexiones personales de las y los estudiantes que, explorando estas temáticas, comparten sus aprendizajes y observaciones de forma vívida.ITESO, A.C

Deep-water macroalgae from the Canary Islands: new records and biogeographical relationships

Due to the geographical location and paleobiogeography of the Canary Islands, the seaweed flora contains macroalgae with different distributional patterns. In this contribution, the biogeographical relations of several new records of deep-water macroalgae recently collected around the Canarian archipelago are discussed. These are Bryopsidella neglecta (Berthotd) Rietema,Discosporangium mesarthrocarpum (Meneghini) Hauck, Hincksia onslowensis (Amsler et Kapraun)P.C. Silva, Syringoderma floridana Henry, Peyssonnelia harveyana J. Agardh, Cryptonemia seminervis(C. Agardh) J. Agardh, Botryodadia wynnei Ballantine, Gloiocladia blomquistii (Searles) R. E.Norris, PIahchrysis peltata (W. R. Taylor) P. Huv4 et H. Huv4, Leptofauchea brasiliensis Joly, and Sarcodiotheca divaricata W. R. Taylor. These new records, especially those in the Florideophyceae,support the strong affinity of the Canary Islands seaweed flora with the warm-temperate Mediterranean-Atlantic region. Some species are recorded for the first time from the east coast of the Atlantic Ocean, enhancing the biogeographic relations of the Canarian marine flora with that of the western Atlantic regions