Estudio del estado ecológico de los ríos de la cuenca hidrográfica del Júcar (España) mediante el índice BMWP'

El diseño de la Red Biológica, basado en el uso de indicadores hidromorfológicos, físico-químicos y biológicos, permitió realizar un diagnóstico de calidad en 221 puntos de muestreo en 104 ríos de la red hidrográfica del Júcar (Júcar, Turia, Mijares, Vinalopó, Palancia, Serpis y cuencas menores) durante el año 2000 y establecer su estado ecológico. En este trabajo se presentan los resultados obtenidos con el índice BMWP'. Los ríos con un estado ecológico muy bueno se hallan situados en los tramos altos, tanto de los ríos principales como de los afluentes de primer y segundo orden. La mayoría de los puntos de referencia (12.7%) se encuentran en altitudes superiores a los 800 m. Los ríos situados en altitudes medias (800-200 m) se hallan muy regulados y presentan, en general, un estado entre bueno y aceptable, existiendo pocos puntos de referencia (6.8%). Por último, los ríos situados en tierras bajas (< 200 m) se encuentran, la gran mayoría, en un estado deficiente o malo, siendo muy difícil hallar ríos en buen estado y casi imposible establecer puntos de referencia con un muy buen estado ecológico (0.5%). Las medidas correctoras propuestas para los ríos de la red hidrográfica del Júcar se centran en la mejora de las características hidromorfológicas y físico-químicas, y por tanto de las comunidades biológicas, con el propósito final de conseguir el mejor estado ecológico y químico posible para las aguas superficiales tal y como exige la DMA (Directiva Marco del Agua).The design of the Biological Network, based on the use of hydromorphological, physical, chemical, and biological indicators, allowed a diagnosis of the quality in 221 sampling points in 104 rivers of Júcar's Basin (Jucar, Turia, Mijares, Vinalopo, Palancia, Serpis and small basins) to be carried out during the year 2000 and to establish its ecological status. In this work the results obtained with the BMWP' index are presented. The rivers with a high ecological status are located in the high altitudes, so much of the main rivers as of the tributaries of first and second order. Most of the reference points (12.7%) are located at altitudes higher than 800 m. The rivers located at middle-altitudes (800-200 m) are very regulated and they present, in general, an ecological status between good and acceptable, with few reference points (6.8%). Last, the rivers located in lowlands (< 200 m) are, mostly, in a poor or bad ecological state, making it very difficult to find rivers in good ecological status and almost impossible to establish reference points with a high ecological status (0.5%). The correcting measures proposed for the rivers of the Júcar's Basin are centered in the improvement of the hydromorphological, physical, and chemical characteristics, and therefore of the biological communities, with the final purpose of achieving the highest ecological and chemical status possible for surface waters like the WFD (Water Framework Directive) demands

Genomic transformation and social organization during the Copper Age-Bronze Age transition in southern Iberia

The emerging Bronze Age (BA) of southeastern Iberia saw marked social changes. Late Copper Age (CA) settlements were abandoned in favor of hilltop sites, and collective graves were largely replaced by single or double burials with often distinctive grave goods indirectly reflecting a hierarchical social organization, as exemplified by the BA El Argar group. We explored this transition from a genomic viewpoint by tripling the amount of data available for this period. Concomitant with the rise of El Argar starting ~2200 cal BCE, we observe a complete turnover of Y-chromosome lineages along with the arrival of steppe-related ancestry. This pattern is consistent with a founder effect in male lineages, supported by our finding that males shared more relatives at sites than females. However, simple two-source models do not find support in some El Argar groups, suggesting additional genetic contributions from the Mediterranean that could predate the BA

Evidence of conditioned behavior in amoebae

Associative memory is the main type of learning by which complex organisms endowed with evolved nervous systems respond efficiently to certain environmental stimuli. It has been found in different multicellular species, from cephalopods to humans, but never in individual cells. Here we describe a motility pattern consistent with associative conditioned behavior in the microorganism Amoeba proteus. We use a controlled direct-current electric field as the conditioned stimulus, and a specific chemotactic peptide as the unconditioned stimulus. The amoebae are capable of linking two independent past events, generating persistent locomotion movements that can prevail for 44 min on average. We confirm a similar behavior in a related species, Metamoeba leningradensis. Thus, our results indicate that unicellular organisms can modify their behavior during migration by associative conditioning.We would like to thank Dr. Andrew Goodkov from the Institute of Cytology (Russian Academy of Science) St. Petersburg, Russia, for valuable advices related to Amoeba organisms, Laura Pérez Gómez and Luis Rojo García for their assistance designing Fig. 1 and the AutoCAD 3D model, A-M Pérez Biedermann for her valuable contribution in our study, José González Romero and José Miguel Pérez Pérez from the Institute of Parasitology and Biomedicine “Lopez-Neyra” for their technical assistance. In addition, we thank María Calleja-Felipe for her valuable help in the peptide gradient experiments. This work was supported by a grant of the University of Basque Country (UPV/EHU), GIU17/066, the Basque Government grant IT974-16, and by the UPV/EHU and Basque Center of Applied Mathematics, grant US18/21”

Effect of feeding frequency on the daily rhythms of acidic digestion in a teleost fish (gilthead seabream)

Gilthead seabream is a fish species of great importance in Mediterranean aquaculture, attracting many studies on nutrition and chronobiology, although nothing is known about the effect of feeding frequency on the daily rhythms of the gastric digestion process. In this article, we investigated daily rhythms in stomach fullness, gastric and intestine pH, as well as pepsin activity and expression of pepsinogen and proton pump in juvenile fish under three different feeding protocols: (A) one daily meal at 9:00, (B) two daily meals at 9:00 and 17:00 and (C) continuous feeding during the daytime. The results revealed that feeding protocol affected significantly the rhythm of gastric pH and the pepsin activity pattern. The gastric pH exhibited significant daily rhythms in the three cases with the acrophase located at night in the regimes A and B and during daytime, in the regime C. In the regimes A and B, the pepsin activity peaked few hours after the meals, although the afternoon meal in B produced a higher peak. In the regime C, the peak occurred in the middle of the feeding period. Lowest total pepsin activity was observed in regime A, and the highest activity with the regime C. In contrast, the pepsinogen gene expression remained low along the daily cycle, with an expression peak just before or after the morning meal in regimes A and C, respectively. The proton pump gene expression was also practically constant with a peak right after the morning meal in the regime C. On the other hand, intestinal pH showed a postprandial increase after the first morning meal in all the three treatments, recovering the resting values in the dark period. Two meals and continuous feeding allowed a better and prolonged gastric digestion and consequently the juveniles exhibited better growth with the same daily ration of food. In short, while the gastric digestion pattern is mainly driven by pH changes induced by the time of food ingestion, the regulation of the intestinal digestion seems to be more independent of the feeding protocol.This research was funded by the Spanish Ministry of Economic Affairs and Competitiveness (MINECO) by projects RIDIGEST (AGL2011-23722) and AQUAGENOMICS (Consolider-Ingenio Program CDS2007-0002) with FEDER/ERDF contribution.Peer reviewe

The maternal genetic make-up of the Iberian Peninsula between the Neolithic and the Early Bronze Age

Agriculture first reached the Iberian Peninsula around 5700 BCE. However, little is known about the genetic structure and changes of prehistoric populations in different geographic areas of Iberia. In our study, we focus on the maternal genetic makeup of the Neolithic (~ 5500–3000 BCE), Chalcolithic (~ 3000–2200 BCE) and Early Bronze Age (~ 2200–1500 BCE). We report ancient mitochondrial DNA results of 213 individuals (151 HVS-I sequences) from the northeast, central, southeast and southwest regions and thus on the largest archaeogenetic dataset from the Peninsula to date. Similar to other parts of Europe, we observe a discontinuity between hunter-gatherers and the first farmers of the Neolithic. During the subsequent periods, we detect regional continuity of Early Neolithic lineages across Iberia, however the genetic contribution of hunter-gatherers is generally higher than in other parts of Europe and varies regionally. In contrast to ancient DNA findings from Central Europe, we do not observe a major turnover in the mtDNA record of the Iberian Late Chalcolithic and Early Bronze Age, suggesting that the population history of the Iberian Peninsula is distinct in character.Concerning research in the Alto Ribatejo, authors wish to thank Fundação para a Ciência e Tecnologia the support of research on the dawn of farming in the Tagus valley (project “Moving Tasks Accross Shapes” – PTDC/EPH-ARQ/4356/2014), as well as the Geosciences Centre of Coimbra University (strategic project UID/Multi/00073/2013). This study was funded by the German Research Foundation (Grant no. Al 287/14–1)