Ontogenetic changes in digestive enzymatic capacities of the spider crab, Maja brachydactyla (Decapoda: Majidae)

Ontogenetic changes in digestive capabilities were analyzed in larvae and first juveniles of the spider crab Maja brachydactyla. Activities of five proteinases (total proteases, trypsin, chymotrypsin, pepsin-like and aminopeptidase), three carbohydrases (amylase, maltase and chitinase), an esterase and an alkaline phosphatase were studied to evaluate digestive enzyme profiles of the species. Both quantitative (spectrophotometry and fluorometry) and qualitative (SDS-PAGE) approaches were used. All assayed enzymes were active from hatching (zoea I-ZI) throughout larval development and in first juveniles. Significant variations during ontogeny were found only in total activities likely as a consequence of digestive system development. Specific activity varied little over ontogeny, being significant only for chitinase. Total proteases, trypsin and pepsin-like activities showed a similar pattern of increase as larval ontogeny advanced, decreasing significantly in juveniles. Chymotrypsin continued to increase, showing maximum activity after metamorphosis. Proteinase zymograms confirmed strong proteolytic activity in first zoeas, with increasing bands over the course of ontogeny, decreasing after metamorphosis. A group of bands with high molecular mass was specific to larval stages. Amylase and maltase showed a parallel pattern of continuous increase of total activity as development advanced. Gel-SDS-PAGE showed unchanged patterns of amylase activity in first zoeas of different ages and the most complex set of bands during larval ontogeny in second zoea. Esterase total activity increased significantly as ZI's aged likely reflecting introduction of a lipid-enriched diet. The importance of lipid accumulation at the beginning of ontogeny was also confirmed by the protease/esterase and amylase/esterase activity ratios, which decreased from hatch to late ZI and might be explained as an adaptation, ensuring the next molt. The results suggest that larvae of M. brachydactyla are capable of digesting a variety of dietary substrates as soon as they hatch.

The implementation of liquid chromatography tandem mass spectrometry for the official control of lipophilic toxins in seafood: Single-laboratory validation under four chromatographic conditions

We performed a comprehensive study to assess the fit for purpose of four chromatographic conditions for the determination of six groups of marine lipophilic toxins (okadaic acid and dinophysistoxins, pectenotoxins, azaspiracids, yessotoxins, gymnodimine and spirolides) by LC-MS/MS to select the most suitable conditions as stated by the European Union Reference Laboratory for Marine Biotoxins (EURLMB). For every case, the elution gradient has been optimized to achieve a total run-time cycle of 12 min. We performed a single-laboratory validation for the analysis of three relevant matrices for the seafood aquaculture industry (mussels, pacific oysters and clams), and for sea urchins for which no data about lipophilic toxins have been reported before. Moreover, we have compared the method performance under alkaline conditions using two quantification strategies: the external standard calibration (EXS) and the matrix-matched standard calibration (MMS). Alkaline conditions were the only scenario that allowed detection windows with polarity switching in a 3200 QTrap mass spectrometer, thus the analysis of all toxins can be accomplished in a single run, increasing sample throughput. The limits of quantification under alkaline conditions met the validation requirements established by the EURLMB for all toxins and matrices, while the remaining conditions failed in some cases. The accuracy of the method and the matrix effects where generally dependent on the mobile phases and the seafood species. The MMS had a moderate positive impact on method accuracy for crude extracts, but it showed poor trueness for seafood species other than mussels when analyzing hydrolyzed extracts. Alkaline conditions with EXS and recovery correction for OA were selected as the most proper conditions in the context of our laboratory. This comparative study can help other laboratories to choose the best conditions for the implementation of LC-MS/MS according to their own necessities.

Metallic and nonmetallic shine in luster: An elastic ion backscattering study

Luster is a metal glass nanocomposite layer first produced in the Middle East in early Islamic times ( 9th AD) made of metal copper or silver nanoparticles embedded in a silica-based glassy matrix. These nanoparticles are produced by ion exchange between Cu+ and Ag+ and alkaline ions from the glassy matrix and further growth in a reducing atmosphere. The most striking property of luster is its capability of reflecting light like a continuous metal layer and it was unexpectedly found to be linked to one single production parameter: the presence of lead in the glassy matrix composition. The purpose of this article is to describe the characteristics and differences of the nanoparticle layers developed on lead rich and lead free glasses. Copper luster layers obtained using the ancient recipes and methods are analyzed by means of elastic ion backscattering spectroscopy associated with other analytical techniques. The depth profile of the different elements is determined, showing that the luster layer formed in lead rich glasses is 5–6 times thinner and 3–4 times Cu richer. Therefore, the metal nanoparticles are more densely packed in the layer and this fact is related to its higher reflectivity. It is shown that lead influences the structure of the metal nanoparticle layer through the change of the precipitation kinetics

Estabilitat i diagènesis dels fitòlits de silici en els jaciments arqueològics

Estudi realitzat a partir d’una estada al Kimmel Center for Archaeological Research, Israel, entre 2010 i 2012. Els fitòlits són un dels components principals dels sediments arqueològics. Són relativament estables i menys propensos a la degradació biològica que altres restes vegetals, però també poden ser afectats per la diagènesis. Per entendre com la diagènesis afecta als fitòlits hem desenvolupat una aproximació experimental utilitzant solucions alcalines per determinar l’estabilitat individual de fitòlits fòssils i moderns. L’experimentació ha estat completada amb un estudi de camp a Izbet Sartah. Els resultats mostren com la diagènesis canvia la composició dels conjunts de fitòlits, i per tant afecta la interpretació arqueològica. Conseqüentment, hem desenvolupat un mètode per determinar l’estat de preservació dels fitòlits en els jaciments arqueològics. L’experimentació mostra com els fitòlits moderns són més solubles que els fitòlits fòssils. Tant els fitòlits fòssils com els moderns són menys estables si són cremats. No totes les morfologies es preserven igual, indicant així que hi ha unes morfologies més estables que unes altres. Els fitòlits amb decoracions delicades, especialment aquells formats a la inflorescència de gramínies, són més propensos a la dissolució que els de les fulles. L’avaluació de l’estat de preservació dels fitòlits en jaciments arqueològics es pot realitzar utilitzant un conjunt de tècniques com ara: l’Index de Variació de Fitòlits, el mètode de dissolució ràpida, la identificació de morfologies delicades i la utilització del FTIR. Proposem que la diagènesis dels fitòlits depèn directament de la quantitat inicial de fitòlits en els sediments, la velocitat de sedimentació, i la presència o absència de fitòlits i plantes modernes en l’àrea estudiada. Els resultats d’aquesta investigació han estat publicats en dos articles afegits al final de l’informe (Cabanes et al., 2011 i Cabanes et al., in press), presentats en congressos internacionals i utilitzats indirectament en altres investigacions.

Las formas graníticas de los macizos de les Gavarres i de Begur (Girona)

In the present paper the granite landforms of the Les Gavarres and Begur massifs (Girona) are described. Also the relationship between this landforms and the lithology are analysed

Las formas graníticas del macizo de l'Ardenya

Granitic Landforms in the Ardenya Massif (Girona, Spain). In this paper the main characteristics of the granite landforms in the Ardenya massif (Girona) are described. The relationship between this landforms and the lithology are analysed

La Pedralta, un ejemplo de patrimonio geológico de Girona

Pedralta is a very large rocking stone shaped in monzonitic granite. Its volume and weight are approximately 34 m3 and 90 Tm. The fall of such block has supposed the loss of a worthy geotipe

Side scan sonar image and geologic interpretation of the Ria de Pontevedra seafloor (Galicia, NW Spain).

High-resolution side scan sonar has been used for mapping the seafloor of the Ría de Pontevedra. Four backscatter patterns have been mapped within the Ría: (1) Pattern with isolated reflections, correlated with granite and metamorphic outcrops and located close to the coastal prominence and Ons and Onza Islands. (2) Pattern of strong reflectivity usually located around the basement outcrops and near the coastline and produced by coarse-grained sediment. (3) Pattern of weak backscatter is correlated with fine sand to mud and comprising large areas in the central and deep part of the Ría, where the bottom currents are weak. It is generally featureless, except where pockmarks and anthropogenic features are present. (4) Patches of strong and weak backscatter are located in the boundary between coarse and fine-grained sediments and they are due to the effect of strong bottom currents. The presence of megaripples associated to both patterns of strong reflectivity and sedimentary patches indicate bedload transport of sediment during high energy conditions (storms). Side scan sonar records and supplementary bathymetry, bottom samples and hydrodynamic data reveal that the distribution of seafloor sediment is strongly related to oceanographic processes and the particular morphology and topography of the Ría.

Electrical signature of modern and ancient tectonic processes in the crust of the Atlas mountains of Morocco.

The Atlas Mountains in Morocco are considered as type examples of intracontinental chains, with high topography that contrasts with moderate crustal shortening and thickening. Whereas recent geological studies and geodynamic modeling have suggested the existence of dynamic topography to explain this apparent contradiction, there is a lack of modern geophysical data at the crustal scale to corroborate this hypothesis. Newly-acquired magnetotelluric data image the electrical resistivity distribution of the crust from the Middle Atlas to the Anti-Atlas, crossing the tabular Moulouya Plain and the High Atlas. All the units show different and unique electrical signatures throughout the crust reflecting the tectonic history of development of each one. In the upper crust electrical resistivity values may be associated to sediment sequences in the Moulouya and Anti-Atlas and to crustal scale fault systems in the High Atlas developed during the Cenozoic times. In the lower crust the low resistivity anomaly found below the Mouluya plain, together with other geophysical (low velocity anomaly, lack of earthquakes and minimum Bouguer anomaly) and geochemical (Neogene-Quaternary intraplate alkaline volcanic fields) evidence, infer the existence of a small degree of partial melt at the base of the lower crust. The low resistivity anomaly found below the Anti-Atlas may be associated with a relict subduction of Precambrian oceanic sediments, or to precipitated minerals during the release of fluids from the mantle during the accretion of the Anti-Atlas to the West African Supercontinent during the Panafrican orogeny ca. 685 Ma).

Las hornblenditas,gabros y dioritas del Macizo del Montnegre (Barcelona, Cordilleras costero catalanas)

En relación con los granitos tardihercínicos calcoalcalinos del Macizo del Montnegre aparecen rocas ultrabásicas-básicas a intermedias. Las más básicas son hornblenditas olivínicas, con espinela, clinopiroxeno, ortopiroxeno, anfíboles de varios tipos y flogopita. Hay además melagabros-gabros hornbléndicos y leucogabros, estos últimos con anfíbol minoritario. Las rocas más ácidas son cuarzodioritas y cuarzomonzodioritas biotítico-hornbléndicas, con cristales relictos de clinopiroxeno y ortopiroxeno. El contenido máximo en anortita de la plagioclasa en las dioritas es tan alto como en los gabros. Toda la asociación muestra una evolución típicamente calcoalcalina, pero las hornblenditas y algunos gabros podrían haberse formado a partir de diferentes tipos de magmas básicos. Las cuarzodioritas serían rocas híbridas, con participación de un magma más básico y otro más ácido. El primero estaría saturado en clinopiroxeno y ortopiroxeno, además de en plagioclasa de composición bitownita, y el otro magma sería más ácido.

Las hornblenditas,gabros y dioritas del Macizo del Montnegre (Barcelona, Cordilleras costero catalanas)

En relación con los granitos tardihercínicos calcoalcalinos del Macizo del Montnegre aparecen rocas ultrabásicas-básicas a intermedias. Las más básicas son hornblenditas olivínicas, con espinela, clinopiroxeno, ortopiroxeno, anfíboles de varios tipos y flogopita. Hay además melagabros-gabros hornbléndicos y leucogabros, estos últimos con anfíbol minoritario. Las rocas más ácidas son cuarzodioritas y cuarzomonzodioritas biotítico-hornbléndicas, con cristales relictos de clinopiroxeno y ortopiroxeno. El contenido máximo en anortita de la plagioclasa en las dioritas es tan alto como en los gabros. Toda la asociación muestra una evolución típicamente calcoalcalina, pero las hornblenditas y algunos gabros podrían haberse formado a partir de diferentes tipos de magmas básicos. Las cuarzodioritas serían rocas híbridas, con participación de un magma más básico y otro más ácido. El primero estaría saturado en clinopiroxeno y ortopiroxeno, además de en plagioclasa de composición bitownita, y el otro magma sería más ácido.

Electrical signature of modern and ancient tectonic processes in the crust of the Atlas mountains of Morocco.

The Atlas Mountains in Morocco are considered as type examples of intracontinental chains, with high topography that contrasts with moderate crustal shortening and thickening. Whereas recent geological studies and geodynamic modeling have suggested the existence of dynamic topography to explain this apparent contradiction, there is a lack of modern geophysical data at the crustal scale to corroborate this hypothesis. Newly-acquired magnetotelluric data image the electrical resistivity distribution of the crust from the Middle Atlas to the Anti-Atlas, crossing the tabular Moulouya Plain and the High Atlas. All the units show different and unique electrical signatures throughout the crust reflecting the tectonic history of development of each one. In the upper crust electrical resistivity values may be associated to sediment sequences in the Moulouya and Anti-Atlas and to crustal scale fault systems in the High Atlas developed during the Cenozoic times. In the lower crust the low resistivity anomaly found below the Mouluya plain, together with other geophysical (low velocity anomaly, lack of earthquakes and minimum Bouguer anomaly) and geochemical (Neogene-Quaternary intraplate alkaline volcanic fields) evidence, infer the existence of a small degree of partial melt at the base of the lower crust. The low resistivity anomaly found below the Anti-Atlas may be associated with a relict subduction of Precambrian oceanic sediments, or to precipitated minerals during the release of fluids from the mantle during the accretion of the Anti-Atlas to the West African Supercontinent during the Panafrican orogeny ca. 685 Ma).

Las hornblenditas,gabros y dioritas del Macizo del Montnegre (Barcelona, Cordilleras costero catalanas)

En relación con los granitos tardihercínicos calcoalcalinos del Macizo del Montnegre aparecen rocas ultrabásicas-básicas a intermedias. Las más básicas son hornblenditas olivínicas, con espinela, clinopiroxeno, ortopiroxeno, anfíboles de varios tipos y flogopita. Hay además melagabros-gabros hornbléndicos y leucogabros, estos últimos con anfíbol minoritario. Las rocas más ácidas son cuarzodioritas y cuarzomonzodioritas biotítico-hornbléndicas, con cristales relictos de clinopiroxeno y ortopiroxeno. El contenido máximo en anortita de la plagioclasa en las dioritas es tan alto como en los gabros. Toda la asociación muestra una evolución típicamente calcoalcalina, pero las hornblenditas y algunos gabros podrían haberse formado a partir de diferentes tipos de magmas básicos. Las cuarzodioritas serían rocas híbridas, con participación de un magma más básico y otro más ácido. El primero estaría saturado en clinopiroxeno y ortopiroxeno, además de en plagioclasa de composición bitownita, y el otro magma sería más ácido.

Late and postmagmatic alterations in the tin-bearing batholith of Ricobayo (Iberian Massif, NW Spain)

The deuteric alteration processes undergone by the granites of the Ricobayo Batholith were: microclinization, chloritization, albitization, muscovitization, tourmalinization and garnetization. These processes must be interpreted in a dynamic context so that the different reactions that take place are the consequence of a successive interaction between rock and fluids. The physicochemical conditions deduced from these fluids are: temperature lower than 600 OC, pressure between 1.5 and 1 Kb, fugacity of oxygen between 10-25 and 10-35 bars, fugacity of sulphur lower than 10-l5 bars, the composition was kept stable and their log (a(K+)/a(Ht)) and log (a(Na+)/a(H+)) varied between 3.8 and 3.2 and between 3.5 and 4.6, respectively, and the pH of the fluids was higher than 5 during the microclinization, muscovitization and tourmalinization, and lower during chloritization and albitization. The deposition of cassiterite occurs with pH episodes that exceed 5.