Pollutants removal from municipal sewage by means of microalgae

Microalgae are microorganisms able to photosynthesize, namely transforming inorganic substrates and sun light into organic compounds and chemical energy. The industry of microalgae has expanded in the last decades and several applications are now developed, making their biomass interesting under an economic perspective. Nannochlopsis gaditana is one of the most interesting species already employed in industry because of its high content in lipids that could be employed as source for biodiesel synthesis but also in other fields such as cosmetic and pharmaceutic. One of the most promising application is the exploitation of microalgal grow for bioremediating wastewaters polluted with inorganic nutrients such as nitrates and phosphates that microalgae are able to employ as nutrients. Bio-treatment of wastewaters by using microalgae has the advantage to reclassify the water and preserve it from wasting while producing a valuable biomass. In this work, a microalgal strain, Nannochloropsis gaditana, was employed for testing its performance in the bioremediation of municipal sewages. The wastewater was taken from a municipal plant, after the primary treatment, and the algae processing was aimed at replacing the secondary treatment. Algal growth in its growth medium and in the sewage was compared and algal biomass was characterized. Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), total nitrogen and total phosphorous levels of the sewage before and after algae treatment were also determined in order to evaluate the efficiency of this microalgal strain on wastewater bioremediation. Our results showed that N. gaditana grows better in wastewater than in the control growth medium and it is able to efficiently remove nutrients from the sewage. However, COD and BOD values did not decrease after algal treatment. These results suggest that the use of selected bacteria and/or yeast strains (together with microalgae) could improve the efficiency of wastewater treatments decreasing BOD and COD values

First DNA barcode reference library for the identification of South American freshwater fish from the lower Paraná river

Valid fish species identification is essential for biodiversity conservation and fisheries management. Here, we provide a sequence reference library based on mitochondrial cytochrome c oxidase subunit I for a valid identification of 79 freshwater fish species from the Lower Paraná River. Neighbour-joining analysis based on K2P genetic distances formed non-overlapping clusters for almost all species with a ≥99% bootstrap support each. Identification was successful for 97.8% of species as the minimum genetic distance to the nearest neighbour exceeded the maximum intraspecific distance in all these cases. A barcoding gap of 2.5% was apparent for the whole data set with the exception of four cases. Withinspecies distances ranged from 0.00% to 7.59%, while interspecific distances varied between 4.06% and 19.98%, without considering Odontesthes species with a minimum genetic distance of 0%. Sequence library validation was performed by applying BOLDs BIN analysis tool, Poisson Tree Processes model and Automatic Barcode Gap Discovery, along with a reliable taxonomic assignment by experts. Exhaustive revision of vouchers was performed when a conflicting assignment was detected after sequence analysis and BIN discordance evaluation. Thus, the sequence library presented here can be confidently used as a benchmark for identification of half of the fish species recorded for the Lower Paraná River.Instituto de Limnología "Dr. Raul A. Ringuelet

12C/13C isotopic ratios in red-giant stars of the open cluster NGC 6791

Carbon isotope ratios, along with carbon and nitrogen abundances, are derived in a sample of 11 red-giant members of one of the most metal-rich clusters in the Milky Way, NGC 6791. The selected red-giants have a mean metallicity and standard deviation of [Fe/H]=+0.39+-0.06 (Cunha et al. 2015). We used high resolution H-band spectra obtained by the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE). The advantage of using high-resolution spectra in the H-band is that lines of CO are well represented and their line profiles are sensitive to the variation of 12C/13C. Values of the 12C/13C ratio were obtained from a spectrum synthesis analysis. The derived 12C/13C ratios varied between 6.3 and 10.6 in NGC 6791, in agreement with the final isotopic ratios from thermohaline-induced mixing models. The ratios derived here are combined with those obtained for more metal poor red-giants from the literature to examine the correlation between 12C/13C, mass, metallicity and evolutionary status.Comment: Accepted for publication in MNRAS, 9 pages, 4 figures, 2 table

Boosting Biomass Quantity and Quality by Improved Mixotrophic Culture of the Diatom Phaeodactylum tricornutum

Diatoms are photoautotrophic unicellular algae and are among the most abundant, adaptable, and diverse marine phytoplankton. They are extremely interesting not only for their ecological role but also as potential feedstocks for sustainable biofuels and high-value commodities such as omega fatty acids, because of their capacity to accumulate lipids. However, the cultivation of microalgae on an industrial scale requires higher cell densities and lipid accumulation than those found in nature to make the process economically viable. One of the known ways to induce lipid accumulation in Phaeodactylum tricornutum is nitrogen deprivation, which comes at the expense of growth inhibition and lower cell density. Thus, alternative ways need to be explored to enhance the lipid production as well as biomass density to make them sustainable at industrial scale. In this study, we have used experimental and metabolic modeling approaches to optimize the media composition, in terms of elemental composition, organic and inorganic carbon sources, and light intensity, that boost both biomass quality and quantity of P. tricornutum. Eventually, the optimized conditions were scaled-up to 2 L photobioreactors, where a better system control (temperature, pH, light, aeration/mixing) allowed a further improvement of the biomass capacity of P. tricornutum to 12 g/L

Genetic diversity and structure of the commercially important native fish pacu (Piaractus mesopotamicus) from cultured and wild fish populations: relevance for broodstock management

Pacu (Piaractus mesopotamicus) is one of the most important Neotropical freshwater fish species produced by aquaculture in South America. This study is the first attempt to inquire about aquaculture stocks in Argentina regarding genetic diversity and structure. Neither genetic characterization nor pedigree records are available for pacu stocks in farms in Argentina. The presence of hybrids in both natural environment (Lower Paraná River) and farms has not been evaluated yet at the southern region of pacu distribution. Genetic characterization of pacu broodstocks, corresponding to 8 farms, and wild individuals from four areas at Lower Paraná River was performed. Pacu hybrids were not detected neither in wild nor in farm stocks analyzed. In general, similar levels of genetic diversity were observed between cultured and wild fish populations. Global genetic differentiation (Fst = 0.055) indicated a low level of structure and AMOVA showed that genetic variation was mostly within populations. Reduced contemporary effective population size (Ne) was observed, and probably reflects the bottleneck by founder effect in farmed fish populations. Moreover, kinship analysis showed that in fish farms, on average, 43.00% of the individuals were genetically related, whereas in wild population it was 36.40%. We recommend that broodstock management practices, such as using large Ne, single pair mating, precise records, and tagging of brood fish, should be implemented to avoid unintentional mismanagement.Fil: Del Pazo, F.. Universidad Nacional de Rosario; ArgentinaFil: Sánchez, Sebastián. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias. Instituto de Ictiología del Nordeste; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Posner, Victoria. Universidad Nacional de Rosario; ArgentinaFil: Sciara, Andrés A.. Universidad Nacional de Rosario; ArgentinaFil: Arranz, Silvia Eda. Universidad Nacional de Rosario; ArgentinaFil: Villanova, Gabriela V.. Universidad Nacional de Rosario; Argentin

Biological and chemical characterization of new isolated halophilic microorganisms from saltern ponds of Trapani, Sicily

Halophilic microorganisms inhabiting hypersaline environments such as salt lakes, Dead Sea, or salt evaporation ponds, have acquired specific cell adaptation to grow within stressful conditions. In this study, we isolated heterotrophic and autotrophic microorganisms from several saltern ponds located at the Natural Reserve “Saline di Trapani e Paceco”, Sicily, Italy. The aim of the study was to investigate the biotechnological potential of new microbial strains from saltern ponds, by capturing their biological and chemical diversity. After the isolation and identification of the sampled strains, their growth capacity was determined under low and high salinity conditions. The metabolomic profiles of heterotrophs and pigments production of photosynthetic organisms were analyzed. In parallel, antiproliferative tests on human cell lines were conducted with total extracts coming from the microorganism cultures, together with repair activity assessment of non-cytotoxic extracts. Some of the isolated strains were found to synthetize known bioactive molecules and to exert bioactivity on human cells. In particular, the high salinity increases cell repair activity, probably due to an higher production of antioxidants pigments (e.g. lutein and fucoxanthin) from photosynthetic microorganisms; same culture condition augment also concentration of molecules with interesting bioactivities, such as ectoine, betaine, trigonelline, amino acids and oxiglutathione from heterotrophic microorganisms. In conclusion, this work represents the first study on the isolation of halophilic microorganisms populating the ‘Trapani-Paceco’ saltern and shows how an interdisciplinary investigation based on marine microbiology, cell biology, and modern metabolomics can disclose their biotechnological potential

Growth hormone-releasing hormone attenuates cardiac hypertrophy and improves heart function in pressure overload-induced heart failure

It has been shown that growth hormone-releasing hormone (GHRH) reduces cardiomyocyte (CM) apoptosis, prevents ischemia/reperfusion injury, and improves cardiac function in ischemic rat hearts. However, it is still not known whether GHRH would be beneficial for life-threatening pathological conditions, like cardiac hypertrophy and heart failure (HF). Thus, we tested the myocardial therapeutic potential of GHRH stimulation in vitro and in vivo, using GHRH or its agonistic analog MR-409. We show that in vitro, GHRH(1-44)NH2attenuates phenylephrine-induced hypertrophy in H9c2 cardiac cells, adult rat ventricular myocytes, and human induced pluripotent stem cell-derived CMs, decreasing expression of hypertrophic genes and regulating hypertrophic pathways. Underlying mechanisms included blockade of Gq signaling and its downstream components phospholipase Cβ, protein kinase Ce, calcineurin, and phospholamban. The receptor-dependent effects of GHRH also involved activation of Gαsand cAMP/PKA, and inhibition of increase in exchange protein directly activated by cAMP1 (Epac1). In vivo, MR-409 mitigated cardiac hypertrophy in mice subjected to transverse aortic constriction and improved cardiac function. Moreover, CMs isolated from transverse aortic constriction mice treated with MR-409 showed improved contractility and reversal of sarcolemmal structure. Overall, these results identify GHRH as an antihypertrophic regulator, underlying its therapeutic potential for HF, and suggest possible beneficial use of its analogs for treatment of pathological cardiac hypertrophy

Au-Decorated Ce-Ti Mixed Oxides for Efficient CO Preferential Photooxidation

We investigated the photocatalytic behavior of gold nanoparticles supported on CeO2-TiO2 nanostructured matrixes in the CO preferential oxidation in H2-rich stream (photo-CO-PROX), by modifying the electronic band structure of ceria through addition of titania and making it more suitable for interacting with free electrons excited in gold nanoparticles through surface plasmon resonance. CeO2 samples with different TiO2 concentrations (0-20 wt %) were prepared through a slow coprecipitation method in alkaline conditions. The synthetic route is surfactant-free and environmentally friendly. Au nanoparticles (<1.0 wt % loading) were deposited on the surface of the CeO2-TiO2 oxides by deposition-precipitation. A benchmarking sample was also considered, prepared by standard fast coprecipitation, to assess how a peculiar morphology can affect the photocatalytic behavior. The samples appeared organized in a hierarchical needle-like structure, with different morphologies depending on the Ti content and preparation method, with homogeneously distributed Au nanoparticles decorating the Ce-Ti mixed oxides. The morphology influences the preferential photooxidation of CO to CO2 in excess of H2 under simulated solar light irradiation at room temperature and atmospheric pressure. The Au/CeO2-TiO2 systems exhibit much higher activity compared to a benchmark sample with a non-organized structure. The most efficient sample exhibited CO conversions of 52.9 and 80.2%, and CO2 selectivities equal to 95.3 and 59.4%, in the dark and under simulated sunlight, respectively. A clear morphology-functionality correlation was found in our systematic analysis, with CO conversion maximized for a TiO2 content equal to 15 wt %. The outcomes of this study are significant advancements toward the development of an effective strategy for exploitation of hydrogen as a viable clean fuel in stationary, automotive, and portable power generators