Interactive effects of solar UV radiation and ammonium on the biomass andnutritional compound production in tank cultivated Hydropuntia corne (Rhodophyta)

Figueroa et al. (2016) Acta Aquaculture 16, 331-332Introduction Hydropuntia cornea is a red alga species cultivated in tanks under nitrogen enrichment with high biomass production and content of high value bioactive compounds (Figueroa et al., 2012; Robledo et al, 2014). In this study, the combined effects (2 × 2 factorial design) of solar radiation (in door (I), green house cutting off the UV radiation and out-door (O) with UV radiation) and nitrogen (ammonium) under high (HN) and low (LN) levels on biomass production (g DW m-2 d-1), biofiltration as Nitrogen uptake efficiency (NUE, %) and Nitrogen uptake rate (NUR, mmol N m-2 h-1), photosynthetic activity as maximal electron transport rate (ETRmax), starch content and antioxidant activity were analyzed in H.cornea grown in tanks for 35 days in the above mentioned conditions. Material and methods The red seaweed Hydropuntia cornea was cultivated in cylindrical tanks of 90 L (0.17 m2 superficial area) with open flow-through N and P-enrichment (5 NH4Cl: 1 KHPO4, in a concentration ranges between 50 - 250 µM). Seaweed density assayed in tanks was 9 g FW L-1. Turnover rates were 64 and 6.4 vol d-1 in high and low flow rate, respectively. Photosynthetic activity was measured by using in vivo chlorophyll a fluorescence associated to photosystem II i.e. Electron transport rate (ETR) expressed as μmol electrons m-2 s-1. Starch (%) was determined according to anthrone method (Brooks et al. 1986) and antioxidant activity was evaluated following ABTS method (Ree et al., 1999) and expressed as Trolox equivalent (μM TEAC g-1 DW). Results Maximal photosynthetic production (ETRmax) increased throughout the culture time. (Fig. 1.A). After 35 d culture, ETRmax was higher under HN than that under LN both under in door and out door conditions (Fig.1A). However, biomass production expressed as g DW m-2 d-1 decreased throughout the experimental time (Fig 1.B). After 35d culture the highest biomass production was reached under HN-O and the lowest under LN-O although the differences were not so high (Fig.1B). The maximal efficiency of N assimilation (NUE %) was greater under LN (98%) than that under HN treatment (72%). NUE decreased throughout the time although after 35 d a clear increase was observed (Table 1). In contrast, the maximal nitrogen uptake rate (NUR) was higher under HN (45.5 mmol N m-2 h-1) than that under LN (25.8 mmol N m-2 h-1). The highest values of both NUE and NUR were obtained under solar radiation (outdoor treatments). Starch ranged from 25.1% (LN-I, 21 d) to 49.6 % (LN-O, 28 d) whereas the highest antioxidant activity was reached under LN-O after 21 d culture (68.5 μM TEAC g-1 DW). After 35d the highest level was again under LN-O (65.2 μM TEAC g-1 DW) followed by HN-O treatment (57.3 μM TEAC g-1 DW).Discussion and conclusions Ammonium supply, simulating fishpond effluents, and full solar irradiation (presence of UV radiation) have a positive effect on photosynthetic rate as ETRmax. The decrease in biomass production in spite of the increase of photosynthetic activity and nitrogen uptake rate is explained because the algae through the time could inverse more energy for the accumulation of metabolites (starch and antioxidant compounds) that that for growth. In any case the highest accumulation of starch and antioxidant activity were observed in the treatments associated to the greatest stress conditions i.e LN and outdoor culture due to UVR can negatively affect biological processes related to growth. As expected, under HN supply NUE was lower than that under LN but NUR was the reverse. H. cornea grown in simulated fishpond effluents displays a high biofiltration rate of inorganic N and accumulates commercially N compounds, as the photoprotector-antioxidant substances, mycosporine-like aminoacids (Figueroa et al., 2012) and C-compounds for nutritional uses or bioethanol production. In this study, the antioxidant activity was much higher than that reported in other seaweeds (Matanjun et al., 2008). H. cornea can be cultured and used to remove nutrient-rich fishpond effluents from aquaculture industries and besides, this biomass provides compounds of high added value for the biotechnology industry. References Brooks, J.R., Griffin, V.K., Kattan, M.W. 1986.A modified method for total carbohydrate analysisof glucose syrups, maltodextrins and other starch hydrolysis products. Cereal Chem 63:465-466. Figueroa, F. L., Korbee, N., Abdala, R., Jerez, C. G., López-de la Torre, M., Güenaga, L., Gómez-Pinchetti, J. L. 2012. Biofiltration of fishpond effluents and accumulation of N-compounds (phycobiliproteins and mycosporine-like amino acids) versus C-compounds (polysaccharides) in Hydropuntia cornea (Rhodophyta). Marine Pollution Bulletin, 64(2), 310-318. Matanjun, P., Mohamed, S., Mustapha, N.M., Ming, C.H. 2008. Antioxidant activities and phenolics content of eight species of seaweeds from north Borneo. J Appl Phycol 20:367–373. Re, R., Pellegrini, N., Proteggente, A., Pannala, A.,Yang,M., Rice-Evans, C. 1999. Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radic Biol Med 26:1231–1237. Robledo, D., Navarro‐Angulo, L., Valdes Lozano, D., Freile‐Pelegrín, Y. 2014. Nutrient removal efficiency of Hydropuntia cornea in an integrated closed recirculation system with pink shrimp Farfantepenaeus brasiliensis. Aquaculture Research, 45(10), 1648-1658Universidad de Málaga.Campus de Excelencia Internacional Andalucia Tech

Host-directed therapy for intracellular bacterial Infections

Antibiotic resistance is an increasing problem in the battle against (bacterial) infectious diseases. The emergence of drug-resistant Mycobacterium tuberculosis (Mtb) threatens to render tuberculosis (TB) untreatable. Efforts to develop novel antibiotics have so far been unsuccessful, calling for additional approaches for treatment of bacterial infections. Intracellular pathogens like Mtb and Salmonella can survive in the host by manipulating host cell signaling. This provides opportunities for novel therapeutic strategies by targeting the host, rather than the bacterium (host-directed therapy). In this thesis we report the development and application of novel (in vitro and in vivo) methods for identifying host genes and proteins involved in host control of intracellular bacteria, as well as chemical compounds that target host molecules as a basis for drug development for host-directed therapies. As a result, we report the identification of RTK inhibitors, the novel kinase inhibitor 97i, the human kinase family PCTAIRE and the host protein DRAM1 as promising leads for further drug development for host-directed therapeutic strategies for intracellular bacterial infections.LUMC / Geneeskund

Fotorregulación y efecto del nitrógeno inorgánico en la acumulación de aminoácidos tipo micosporina en algas rojas

En este trabajo se analizará el papel de la radiación lumínica y la disponibilidad de nutrientes en la fotosíntesis y en la acumulación de pigmentos fotosintéticos y moléculas fotoprotectoras. La radiación solar es la fuente primaria de energía para la vida sobre la Tierra; ésta puede afectar al crecimiento y al desarrollo de las plantas tanto como fuente de energía mediante la fotosíntesis, como fuente de calor y como fuente de información ambiental. La irradiancia, la composición espectral, la dirección con que incide y su fotoperiodo son aspectos del ambiente lumínico que cambian en condiciones naturales y proporcionan información acerca de las condiciones ambientales. Las plantas poseen fotorreceptores que les permiten emplear dicha información en la modulación de distintos aspectos del crecimiento y desarrollo. Las algas necesitan carbono inorgánico, agua, luz y nutrientes para la fotosíntesis y el crecimiento. El nitrógeno es uno de los elementos químicos más abundantes en la materia viva, todos los aminoácidos contienen nitrógeno y está presente en otras importantes biomoléculas (como son la clorofila, la ficobiliproteína, etc). También es el elemento que con más frecuencia limita el crecimiento algal. La asimilación de nitrógeno es un proceso dependiente de la fotosíntesis y del metabolismo del carbono para el aporte de poder reductor, ATP y esqueletos carbonados. Por ello, no sólo el nitrógeno inorgánico, sino también la luz y los azúcares, actúan como señales que modulan positivamente la síntesis y la actividad de diversas enzimas relacionadas con la asimilación del nitrógeno. En el primer apartado de la introducción se abordarán los efectos biológicos que induce la RUV en los organismos acuáticos y los posibles mecanismos de fotoprotección presentes en los mismos, como la presencia de moléculas pantalla de esta banda de RUV, entre las que se encuentran los aminoácidos tipo micosporina (MAAs, de su abreviatura en inglés mycosporinelike amino acids). Estas moléculas, además de poseer una estructura química que les permite absorber estas longitudes de onda, poseen nitrógeno entre los elementos químicos que la componen. Nos planteamos la posibilidad de que su presencia no sólo se relacione con la cantidad de radiación recibida, sino que también pueda estar relacionada con la disponibilidad relativa de nutrientes (concretamente de nitrógeno) en el medio de cultivo. En el segundo apartado de la introducción se tratará este aspecto

Patrones estacionales de fotoaclimatación en el alga intermareal, Cystoseira tamariscifolia (Ochrophyta)

Cystoseira tamariscifolia thalli collected from rocky shores and rockpools in winter and summer in Southern Spain were incubated for 7 days in UV transparent cylindrical vessels under outdoor conditions. Photosynthetic activity estimated as in vivo chlorophyll α fluorescence of photosystem II, photosynthetic pigments, antioxidant activity (DPPH assay), phenolic compounds and total internal C and N contents were determined after short-term (3 d) and mid-term (7 d) periods. Maximum quantum yield of PSII (Fv/Fm) was significantly higher in field-collected algae and after 7 d incubation in winter than in summer. In rocky shores and rockpools thalli, maximum electron transport rate (ETRmax) and photosynthetic efficiency (αETR) were much higher in summer than in winter. ETR of outdoor-grown thalli (in situ ETR) showed a daily pattern, with a decrease at noon in both winter and summer (3rd and 7th days). We found much higher antioxidant activity in thalli collected in summer than in winter. However, the concentration of internal UV screen substances (polyphenols) was higher in winter than in summer, whereas the release of phenolic compounds was lower. The highest capacity of acclimation in C. tamariscifolia found in summer and RS with emersion periods was explained by the highest dynamic photoinhibition, energy dissipation (non-photochemical quenching) and antioxidant activity (EC50).Talos de Cystoseira tamariscifolia recolectados en pozas y plataformas rocosas intermareales (Sur de España) en invierno y en verano se incubaron bajo radiación solar durante 7 días en recipientes cilíndricos de metacrilato transparentes a la radiación UV. Se estimó la actividad fotosintética a través de la fluorescencia de la clorofila α asociada al fotosistema II, el contenido de pigmentos fotosintéticos y compuestos fenólicos, actividad antioxidante y el contenido total en C y N internos tras 3 y 7 días de incubación. Los valores iniciales del rendimiento cuántico máximo (Fv/Fm) fueron significativamente mayores en algas recolectadas en invierno que en verano mientras que la tasa de transporte electrónico máximo (ETRmax) y la eficiencia fotosintética fueron mayores en verano que en invierno en ambas zonas. Por otra parte, la tasa de transporte electrónico determinada bajo radiación solar presentó un patrón diario, con una disminución a mediodía, tanto en invierno como en los períodos de verano. La actividad antioxidante fue mayor en algas recogidas en verano; sin embargo, la concentración interna de compuestos fenólicos fue mayor en invierno que en verano, mientras que en la tasa de excreción se observó lo contrario. La alta capacidad de aclimatación en C. tamariscifolia en algas sometidas a emersión en las plataformas rocosas en verano se explica por su alta fotoinhibición dinámica, su capacidad de disipación de energía (amortiguamiento no fotoquímico, NPQ) y su actividad antioxidante (EC50)

Effect of three LED lights on the biomass production and copper remediationby shoot cultures ofMusa paradisiaca

In photosynthesis, certain wavelengths of radiation are absorbed by photosynthetic pigments in plants, depending on the molecular structures of the pigments. Two main radiation wavelengths absorbed by plants for photosynthesis and biomass production are in the range of red and blue lights. Therefore, in addition to white light,observation applying the red and blue lights in plant researches gain great interest. The aim of this project is to compare the effect of three LED lights on the biomass production and copper remediation by previously-screened shoot cultures of Musa paradisiaca.The LED lights applied are arrangements of white, red, and blue LEDs, each arrangement having the same voltage of 12 V and the same power of 24 Watts. The shoot cultures were cultivated aseptically in 25 mL Murashige and Skoog agar media supplemented with 5 mg/L copper ions. Both parameters–the biomass production and copper concentration in biomass–determine the overall copper remediation by the shoot cultures from media. The results of this project show about 1.5-fold biomass production–expressed as growth index–was obtained upon the application of white light compared to that of the other two lights.Meanwhile, there is no significant difference in the concentration of copper in biomass upon the application of the three lights. Combined together, the application of white light still predominates for the overall copper remediation by the shoot cultures of Musa paradisiaca from medi