Malta E.-J.,IFAPA Centro Agua del Pino |
de Nys R.,James Cook University
Journal of Applied Phycology | Year: 2016
One of the main challenges of seaweed culture is to maximize the content of potentially valuable carbon constituents while maintaining high growth rates, thereby improving the value of culture process. This may be achieved by the manipulation of cultivation conditions, inducing a short-term imbalance in carbon metabolism. Here, we tested this concept in the chlorophyte seaweed Ulva ohnoi in a pilot land-based seaweed cultivation system. A first experiment used an abrupt 95 % reduction in water flow and therefore nutrient flux. The content of carbohydrate and lipid of Ulva increased by 16 and 14 % respectively within 2 days compared to the control, whereas growth rates decreased by <5 %. Consequently, the total yield of carbohydrate and lipid increased by ≥10 % compared to the control treatment. A second experiment used a reduction in the density of Ulva under culture by 50 % compared to a control thereby significantly increasing light and the proportional supply of nutrients. The growth rate of Ulva increased by 50 % within 4 days compared to the control, however, there was no change in biochemical composition. Photosynthetic efficiency (effective and maximum quantum yield of photosystem II using Chl a fluorescence) did not respond to the conditions in both experiments. We conclude that short-term treatments can contribute to a preharvest strategy to either improve the biochemical composition or the growth rate of cultivated algae that can in turn lead to an increased yield of targeted compounds. © 2015, Springer Science+Business Media Dordrecht.
Martinez-Pita I.,IFAPA Centro Agua del Pino |
Garcia F.J.,Pablo De Olavide University |
Pita M.-L.,University of Seville
Helgoland Marine Research | Year: 2010
The aim of this study was to analyze male and female gonad fatty acids of two sea urchin species, Paracentrotus lividus and Arbacia lixula, from the south coast of Spain. Additionally, we investigated possible differences between two locations. The ovaries of both species showed higher percentages of 14:0, 16:0, 16:1n-7, 18:2n-6, 18:3n-3 and 18:4n-3 than testes and lower levels of 18:0, 22:1n-9, 20:4n-6 and 22:5n-3. In P. lividus but not in A. lixula, the level of 20:5n-3 was higher in testes than in ovaries. These differences between sexes probably indicate different requirements of males and females during gametogenesis although the presence of a large number of gametes in the mature gonad may also have influences on fatty acid composition. Significant differences in gonad fatty acid profiles where also found when individuals of P. lividus collected at a location of the Mediterranean region were compared with specimens collected at the Atlantic coast. The most remarkable changes were the lower levels of 14:0, 18:1n-7, 20:1n-9, 20:4n-6 and 22:4n-6 and the higher values of 20:1n-11, 20:5n-3 and 22:6n-3 found in males and females of the Mediterranean specimens compared to those of the Atlantic coast. These differences probably reflect the differences in potential food sources at each location. © 2009 Springer-Verlag and AWI.
Determination of selenomethionine and seleno-methyl-selenocysteine in biota by ultrasonic-assisted enzymatic digestion and multi-shot stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry
Mellano F.,National University of Santiago del Estero |
Bujalance M.,University of Huelva |
Giraldez I.,University of Huelva |
Ruiz-Azcona P.,IFAPA Centro Agua del Pino |
And 2 more authors.
Journal of Chromatography A | Year: 2013
A method based on stir bar sorptive extraction (SBSE) and thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS) has been optimized for the determination of seleno-methyl-selenocysteine (SeMetSeCys) and selenomethionine (SeMet) in biota samples. Aliquots of freeze-dried tissue, a mixture of protease XIV-lipase and water were sonicated for 2min. After extraction, the extract was separated by centrifugation and subjected to derivatization and SBSE-TD-GC-MS. The parameters affecting derivatization, absorption and desorption steps were investigated. The optimized conditions consist of a derivatization with 40μL of ethyl chloroformate (ECF) in 400μL of a water:ethanol:pyridine (60:32:8) mixture, followed by dilution to 1.5mL of 70g NaClL-1 in water at neutral pH and an extraction step using 10mm×1mm PDMS stir bar, stirring at 800rpm for 20min at room temperature (23±1°C). Three stir bars were used for the extraction of three different aliquots of the same sample and then placed in a single glass desorption liner and simultaneously desorbed for GC-MS analysis. The desorption step required the following conditions: 300°C (desorption temperature), 6min (desorption time), 50mLmin-1 (vent flow) and -5°C (cryotrapping temperature). The method provided precise (8.1%) and accurate results in the mgSekg-1 range (using the selected-ion monitoring-SIM mode) against certified reference material SELM-1 yeast, with recoveries higher than 80% for spiked algae and clams samples. © 2013 Elsevier B.V.
Martinez-Pita I.,IFAPA Centro Agua del Pino |
Sanchez-Lazo C.,IFAPA Centro Agua del Pino |
Garcia F.J.,Pablo De Olavide University
Aquaculture Nutrition | Year: 2016
The effect of microalga lipid composition on the reproduction of the mussel Mytilus galloprovincialis has been assessed to determine the best feeding strategy for producing large quantities of mussel seed. Three diets based on two microalgae Isochrysis galbana (clon T-iso) and Chaetoceros gracilis were tested. Besides, hatchery groups were compared with mussels from natural populations. Lipid content and fatty acid profile of digestive gland and mantle of both sexes, eggs and microalgae were analysed and related to sexual maturation. Hatchery groups, specifically the one fed on T-iso, showed better results in reproduction success, and these differences were reflected on tissue and egg lipid composition. Microalga fatty acid profile influenced tissues and sexes, and higher levels of 18:1n-9, 22:6n-3 (DHA) and 18:2n-6 were detected in groups fed on T-iso while higher level of 20:5n-3 (EPA) and 16:1n-7 in groups fed on C. gracilis. Evidence of synthesis capacity of EPA from 18:4n-3 and DHA from EPA is detected comparing their levels and the mobilization between tissues. Egg fatty acid profile was influenced by the female diet, and differences among groups were detected and confirmed by PCAs. © 2016 John Wiley & Sons Ltd.
Lopez J.R.,IFAPA Centro Agua del Pino |
Hamman-Khalifa A.M.,University of Granada |
Navas J.I.,IFAPA Centro Agua del Pino |
De la Herran R.,University of Granada
FEMS Microbiology Letters | Year: 2011
The aims of this work were to characterize the 16S-23S internal spacer region of the fish pathogen Tenacibaculum soleae and to develop a PCR assay for its identification and detection. All T. soleae strains tested displayed a single internal spacer region class, containing tRNAIle and tRNAAla genes; nevertheless, a considerable intraspecific heterogeneity was observed. However, this region proved to be useful for differentiation of T. soleae from related and non-related species. Species-specific primers were designed targeting the 16S rRNA gene and the internal spacer region region, yielding a 1555-bp fragment. Detection limit was of 1 pg DNA per reaction (< 30 bacterial cells) when using pure cultures. The detection level in the presence of DNA from fish or other bacteria was lower; however, 10 pg were detected at a target/background ratio of 1 105. The PCR assay proved to be more sensitive than agar cultivation for the detection of T. soleae from naturally diseased fish, offering a useful tool for diagnosis and for understanding the epidemiology of this pathogen. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd.