Trace-metaldynamics in response of increase CO₂ and iron availability in a coastal mesocosm experiment

A mesocosm experiment was performed in the Raunefjord (Norway) to study changes in dissolved Cu (dCu) and Fe (dFe), and in the elemental composition of particles during an Emiliania huxleyi dominated bloom. The CO2 treatments consisted of present (LC; 390 ppmV) and predicted levels (HC; 900 ppmV) and iron conditions were created with the addition of the siderophore desferoxamine B (DFB). Our results showed the DFB addition enhanced the solubility of Fe in this fjord environment. Initially, dFe was comparable among treatments but after the addition, the HC and/or +DFB treatments presented higher levels and finally, the only ones maintaining high dFe were the +DFB treatments. Unlike dCu presented indistinguishable levels in all mesocosms over time. Particulate metals were normalised to P and Al to evaluate the relative influence of biotic and abiotic sources. The Fe:P ratios decreased with time and compared to published phytoplankton ratios suggest Fe storage. On the other hand, Fe:Al ratios were relatively closer to the crustal ratios suggesting that the abiotic source was more important for this metal. Trends for other metals will be discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A network perspective on the evolution of metabolism by gene duplication

BACKGROUND: Gene duplication followed by divergence is one of the main sources of metabolic versatility. The patchwork and stepwise models of metabolic evolution help us to understand these processes, but their assumptions are relatively simplistic. We used a network-based approach to determine the influence of metabolic constraints on the retention of duplicated genes. RESULTS: We detected duplicated genes by looking for enzymes sharing homologous domains and uncovered an increased retention of duplicates for enzymes catalyzing consecutive reactions, as illustrated by the ligases acting in the biosynthesis of peptidoglycan. As a consequence, metabolic networks show a high retention of duplicates within functional modules, and we found a preferential biochemical coupling of reactions that partially explains this bias. A similar situation was found in enzyme-enzyme interaction networks, but not in interaction networks of non-enzymatic proteins or gene transcriptional regulatory networks, suggesting that the retention of duplicates results from the biochemical rules governing substrate-enzyme-product relationships. We confirmed a high retention of duplicates between chemically similar reactions, as illustrated by fatty-acid metabolism. The retention of duplicates between chemically dissimilar reactions is, however, also greater than expected by chance. Finally, we detected a significant retention of duplicates as groups, instead of single pairs. CONCLUSION: Our results indicate that in silico modeling of the origin and evolution of metabolism is improved by the inclusion of specific functional constraints, such as the preferential biochemical coupling of reactions. We suggest that the stepwise and patchwork models are not independent of each other: in fact, the network perspective enables us to reconcile and combine these models

The hidden universal distribution of amino acid biosynthetic networks: a genomic perspective on their origins and evolution

A core of widely distributed network branches biosynthesizing at least 16 out of the 20 standard amino acids is predicted using comparative genomics

Elevated CO₂ alleviates high PAR and UV stress in the unicellular Chlorophyte Dunaliella tertiolecta

The effects of increased CO2 and irradiance on the physiological performance of the chlorophyte Dunaliella tertiolecta were studied at different PAR and UVR (UVA+UVB) irradiances, simulating the solar radiation at different depths, under present (390 ppmv, LC) and predicted CO2 levels (1000 ppmv, HC). Cell stress after UVR-exposure was mostly attenuated under HC levels, as evidenced by a decrease in reactive oxygen species accumulation. DNA damage showed a 42-fold increase in cyclobutane-pyrimidine dimers formation under the highest irradiance in LC with respect to the lowest irradiance. Photolyase gene expression was upregulated under HC resulting in a drastic decrease in CPDs accumulation to only 25% with respect to LC. However, the expression of genes related to the replacement of photosynthetic apparatus proteins (PsbA and LHCII) were downregulated at HC compared to LC. Proliferating cell nuclear antigen (PCNA) accumulation was always higher in HC and the accumulation pattern indicated its involvement in DNA repair or growth depending on the irradiance doses. Our results suggest that marine unicellular chlorophytes might possibly become more resilient to UVR exposure under future CO2 regimes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The effects of ocean acidification and siderophore additions on trace-metal dynamics during an Emiliania Huxleyi- dominated bloom in a coastal mesocosm experiment

The combined impacts of high CO2 and changes in trace metal availability on plankton remain largely unknown. A 22 days mesocosm experiment was carried out in the Raunefjord, off Bergen, Norway (June 2012) to investigate the interactive effects of increased CO2 and changes in iron availability in the pelagic community. Twelve mesocosms covered by PAR and UVR transparent lids were used. The CO2 treatments consisted of present (LC; 390 ppmV) and predicted levels for year 2100 (HC; 900 ppmV). On day 7, half of the mesocoms were amended with the siderophore desferoxamine B (DFB) at 70 nM (final concentration). We studied changes in dissolved Cu (dCu) and Fe (dFe), and in the elemental composition of particles. Dissolved Fe and dCu were measured by chemiluminescence flow injection analysis, while particulate metals were determined by high-resolution inductively coupled mass spectrometry. The metals were normalised to P and Al to evaluate the relative influence of biotic and abiotic sources. Samples were taken throughout a bloom of the coccolithophore E. huxleyi. Further details will be discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Effect of increased CO2 and dissolved iron on primary productivity and inorganic carbon uptake during a bloom of the coccolithophore Emiliania huxleyi

Net primary production (NPP) and inorganic carbon uptake were analysed during a bloom of Emiliania huxleyi in mesocosms. The experiment lasted 25 days and was carried out in the Raunefjord off Bergen (Norway, June 2012) in order to investigate the interactive effects of increased CO2 and iron availability on the phytoplanktonic community. For this purpose two different partial pressures of CO2 corresponding to present (390 ppmV) and predicted levels for year 2100 (900ppmV) (LC and HC respectively) were used. The siderophore desferoxamine B (DFB) was added to half of the mesocosms to create two different iron conditions (+DFB and –DFB). Three mesocosm bags were used for each treatment. NPP was estimated using short-term 14C uptake assays. The isotope disequilibrium assay (ID) was used to determine the relative fraction of HCO3- and CO2 uptake in concentrated cell suspensions. Short-term cellular 14C fixation was monitored during a transient disequilibrium between 14CO2 and H14 CO3- in solution, and so, the fraction of HCO3- uptake (f) and the rate of extracellular CO2: HCO3- interconversion (α), as a measure of extracellular carbonic anhydrase activity (eCA), were calculated. Further details will be discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Evaluación de la distribución de compuestos fenólicos en las fases del alperujo: aporte a su manejo

La finalidad de la presente publicación es transferir al sector agrícola y agroindustrial los resultados de los estudios llevados a cabo por nuestro equipo de investigación en la Facultad de Ciencias Agrarias de la UNCA y que fueran presentados en eventos científicos y evaluados por expertos en la temática.Fil: Gomez, Patricia. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Segovia, Adrian Federico. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Lorenzo, María Emilia. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ribotta, Pablo Daniel. Universidad Nacional de Córdoba. Secretaría de Ciencia y Tecnología. Instituto Superior de Investigación, Desarrollo y Servicio de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bravo, Maria. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; ArgentinaFil: Burgos, Antonella. Universidad Nacional de Catamarca. Facultad de Ciencias Agrarias; Argentin

Basic symptoms and cognitive dynamic disorders in schizophrenic patients

Producción CientíficaUsing a new scientific paradigm, chaotic-deterministic dynamics, our research group developed a new cognitive instrument which is administered by means of a computen the Test of Random Rhythm Generation (ARG). Theoretical background and preliminary results in two young male, defectual schizophrenic patients (paranoid type) are here presented. Basic symptoms were explored by means of the Frankfurt Complaint Questionnaire of FBF (Frankfurter Beschwerde-Fragebogen) and the Bonn Scale for the Assessment of Basic Symptoms of Gross et al. Possible relationships between cerebral complexity and basic symptoms are discussed. It is concluded that the ARG is a valuable technique to measure the patient's cognitive potential as well as his complexity level (or cerebral chaotic dynamic complexity). Finally, it is hypothesized that defectual psychotic patients genérate more rigid and rhythmic series than control groups. Further work must be done in this new research field

Loosenin, a novel protein with cellulose-disrupting activity from Bjerkandera adusta

<p>Abstract</p> <p>Background</p> <p>Expansins and expansin-like proteins loosen cellulose microfibrils, possibly through the rupture of intramolecular hydrogen bonds. Together with the use of lignocellulolytic enzymes, these proteins are potential molecular tools to treat plant biomass to improve saccharification yields.</p> <p>Results</p> <p>Here we describe a new type of expansin-related fungal protein that we have called loosenin. Its corresponding gene, <it>loos1</it>, from the basidiomycete <it>Bjerkandera adusta</it>, was cloned and heterologously expressed in <it>Saccharomyces cerevisiae</it>. LOOS1 is distantly related to plant expansins through the shared presence of a DPBB domain, however domain II found in plant expansins is absent. LOOS1 binds tightly to cellulose and chitin, and we demonstrate that cotton fibers become susceptible to the action of a commercial cellulase following treatment with LOOS1. Natural fibers of <it>Agave tequilana </it>also become susceptible to hydrolysis by cellulases after loosenin treatment.</p> <p>Conclusions</p> <p>LOOS1 is a new type of protein with disrupting activity on cellulose. LOOS1 binds polysaccharides, and given its enhancing properties on the action of hydrolytic enzymes, LOOS1 represents a potential additive in the production of fermentable sugars from lignocellulose.</p

Increased CO2 and iron availability effects on carbon assimilation and calcification on the formation of Emiliania huxleyi blooms in a coastal phytoplankton community

In the present work, we exposed a natural phytoplankton community to either present (390-μatm, LC) or future CO2 levels predicted for year-2100 (900-μatm, HC) combined with ambient (4.5 nmol L−1, −DFB) or high (12 nmol L−1, +DFB) dissolved iron (dFe) levels, during 25 days by using mesocosms. We report on changes in carbon assimilation processes (acquisition, fixation, and calcification) of the phytoplankton community due to increased dissolved CO2 and dFe and to the interaction of both factors. The isotopic disequilibrium assay results showed that inorganic carbon (Ci) acquisition by the community was unaffected by CO2 and Fe availability. The main Ci source for photosynthesis was bicarbonate and external carbonic anhydrase activity was only detected at the beginning of the experiment, suggesting a relevant role for bicarbonate transporters in the phytoplankton community developed in all treatments. However, there was a significant effect of both factors on particulate organic carbon (POC) content, particulate calcium production and carbon fixation rates. Increased dFe at LC conditions led to the highest values of carbon fixation and POC of all treatments, promoting a massive Emiliania huxleyi bloom. This response was not observed in the HC treatments. The latter indicates a negative impact of increased CO2 on the formation of E. huxleyi blooms, in agreement with the observed significant reduction in calcium production under HC. Our results suggest that ocean acidification can decrease primary production under iron-replete conditions in E. huxleyi blooming areas, affecting the biological carbon pump in coastal ecosystems