The fossil record and evolution of freshwater plants: A review

Palaeobotany applied to freshwater plants is an emerging field of palaeontology. Hydrophytic plants reveal evolutionary trends of their own, clearly distinct from those of the terrestrial and marine flora. During the Precambrian, two groups stand out in the fossil record of freshwater plants: the Cyanobacteria (stromatolites) in benthic environments and the prasinophytes (leiosphaeridian acritarchs) in transitional planktonic environments. During the Palaeozoic, green algae (Chlorococcales, Zygnematales, charophytes and some extinct groups) radiated and developed the widest range of morphostructural patterns known for these groups. Between the Permian and Early Cretaceous, charophytes dominated macrophytic associations, with the consequence that over tens of millions of years, freshwater flora bypassed the dominance of vascular plants on land. During the Early Cretaceous, global extension of the freshwater environments is associated with diversification of the flora, including new charophyte families and the appearance of aquatic angiosperms and ferns for the first time. Mesozoic planktonic assemblages retained their ancestral composition that was dominated by coenobial Chlorococcales, until the appearance of freshwater dinoflagellates in the Early Cretaceous. In the Late Cretaceous, freshwater angiosperms dominated almost all macrophytic communities worldwide. The Tertiary was characterised by the diversification of additional angiosperm and aquatic fern lineages, which resulted in the first differentiation of aquatic plant biogeoprovinces. Phytoplankton also diversified during the Eocene with the development of freshwater diatoms and chrysophytes. Diatoms, which were exclusively marine during tens of millions of years, were dominant over the Chlorococcales during Neogene and in later assemblages. During the Quaternary, aquatic plant communities suffered from the effects of eutrophication, paludification and acidification, which were the result of the combined impact of glaciation and anthropogenic disturbance.

Sobre dos supuestas protofitas

Durante algún tiempo conservé la descripción y la figura de un curioso objeto, encontrado entre algas de agua dulce y que creí una clorofícea de muy especiales caracteres. Al contemplar por primera vez polen de mimosa, vi en el campo del microscopio innumerables ejemplares de mi extraordinaria «alga», cuya identidad quedaba así inequívocamente definida...

Regiones limnológicas de Cataluña y ensayo de sistematización de las asociaciones de algas

Los deseos de tipificación y clasificación de las masas de agua dulce han llevado a establecer una tipología tipos de biótopos acuáticos, tipos biológicos de lagos y, al observar la mayor frecuencia con que ciertos tipos se presentan en determinadas regiones por razones climáticas, edáficas (geológicas) y, en menor grado, morfológicas a la llamada limnología regional.

Hábitos higiénico-dietéticos respecto al consumo de alimentos ricos en yodo durante el primer trimestre de la gestación

Objetivo: Conocer los hábitos higiénico-dietéticos de las mujeres embarazadas respecto al consumo de alimentos ricos en yodo durante el primer trimestre de la gestación. Material y método: Estudio observacional, descriptivo, transversal y multicéntrico. Se estudiaron las mujeres embarazadas en el primer trimestre de la gestación que acudieron a la consulta de control del embarazo del programa de atención a la salud sexual y reproductiva (ASSIR) de la Región Sanitaria del Ámbito Centro del Instituto Catalán de la Salud durante el año 2006. Para la recogida de datos se utilizó un cuestionario que cumplimentó la matrona en una entrevista individual en la primera visita de control de embarazo. Resultados: Se recogieron 823 cuestionarios cumplimentados. El 6% (50) de las gestantes no consumía pescado y el 83% (683) lo hacía menos de cuatro veces por semana. El 17% (138) no consumía leche y el 39% (324) bebía un vaso al día. El 42% (342) de las gestantes utilizaba sal yodada para la preparación y condimentación de los alimentos, frente al 50% (412) que no la empleaba. El 22% (184) de las gestantes tomaba algún tipo de suplemento de yodo, y el 18% (148) de la muestra manifestó ser fumadora. Conclusiones: Las mujeres embarazadas de nuestro ámbito de estudio tienen un consumo reducido de alimentos ricos en yodo. Además, tanto el consumo de sal yodada como la utilización de suplementos que contengan yodo durante el embarazo resultan también insuficientes.

Hábitos higiénico-dietéticos respecto al consumo de alimentos ricos en yodo durante el primer trimestre de la gestación

Objetivo: Conocer los hábitos higiénico-dietéticos de las mujeres embarazadas respecto al consumo de alimentos ricos en yodo durante el primer trimestre de la gestación. Material y método: Estudio observacional, descriptivo, transversal y multicéntrico. Se estudiaron las mujeres embarazadas en el primer trimestre de la gestación que acudieron a la consulta de control del embarazo del programa de atención a la salud sexual y reproductiva (ASSIR) de la Región Sanitaria del Ámbito Centro del Instituto Catalán de la Salud durante el año 2006. Para la recogida de datos se utilizó un cuestionario que cumplimentó la matrona en una entrevista individual en la primera visita de control de embarazo. Resultados: Se recogieron 823 cuestionarios cumplimentados. El 6% (50) de las gestantes no consumía pescado y el 83% (683) lo hacía menos de cuatro veces por semana. El 17% (138) no consumía leche y el 39% (324) bebía un vaso al día. El 42% (342) de las gestantes utilizaba sal yodada para la preparación y condimentación de los alimentos, frente al 50% (412) que no la empleaba. El 22% (184) de las gestantes tomaba algún tipo de suplemento de yodo, y el 18% (148) de la muestra manifestó ser fumadora. Conclusiones: Las mujeres embarazadas de nuestro ámbito de estudio tienen un consumo reducido de alimentos ricos en yodo. Además, tanto el consumo de sal yodada como la utilización de suplementos que contengan yodo durante el embarazo resultan también insuficientes.

La caries del biberón. Qué es y cómo prevenirla

La caries del biberón es la aparición brusca de caries en los incisivos y molares temporales, relacionadas con el hábito de succionar el chupete o el biberón, impregnados de sustancias cariogénicas. Afecta a los niños en las primeras etapas de la vida. Los dientes de leche son fundamentales para diferentes funciones como la masticación y el habla. Este trabajo revisa cuáles son sus causas más comunes y las medidas preventivas más indicadas.

Dendritic Spine Abnormalities in Hippocampal CA1 Pyramidal Neurons Underlying Memory Deficits in the SAMP8 Mouse Model of Alzheimer's Disease

SAMP8 is a strain of mice with accelerated senescence. These mice have recently been the focus of attention as they show several alterations that have also been described in Alzheimer"s disease (AD) patients. The number of dendritic spines, spine plasticity, and morphology are basic to memory formation. In AD, the density of dendritic spines is severely decreased. We studied memory alterations using the object recognition test. We measured levels of synaptophysin as a marker of neurotransmission and used Golgi staining to quantify and characterize the number and morphology of dendritic spines in SAMP8 mice and in SAMR1 as control animals. While there were no memory differences at 3 months of age, the memory of both 6- and 9-month-old SAMP8 mice was impaired in comparison with age-matched SAMR1 mice or young SAMP8 mice. In addition, synaptophysin levels were not altered in young SAMP8 animals, but SAMP8 aged 6 and 9 months had less synaptophysin than SAMR1 controls and also less than 3-month-old SAMP8 mice. Moreover, while spine density remained stable with age in SAMR1 mice, the number of spines started to decrease in SAMP8 animals at 6 months, only to get worse at 9 months. Our results show that from 6 months onwards SAMP8 mice show impaired memory. This age coincides with that at which the levels of synaptophysin and spine density decrease. Thus, we conclude that together with other studies that describe several alterations at similar ages, SAMP8 mice are a very suitable model for studying AD.

Inhibition of nociceptive responses after systemic administration of amidated kyotorphin

BACKGROUND AND PURPOSE Kyotorphin (KTP; L-Tyr-L-Arg), an endogenous neuropeptide, is potently analgesic when delivered directly to the central nervous system. Its weak analgesic effects after systemic administration have been explained by inability to cross the blood-brain barrier (BBB) and detract from the possible clinical use of KTP as an analgesic. In this study, we aimed to increase the lipophilicity of KTP by amidation and to evaluate the analgesic efficacy of a new KTP derivative (KTP-amide - KTP-NH 2). EXPERIMENTAL APPROACH We synthesized KTP-NH 2. This peptide was given systemically to assess its ability to cross the BBB. A wide range of pain models, including acute, sustained and chronic inflammatory and neuropathic pain, were used to characterize analgesic efficacies of KTP-NH 2. Binding to opioid receptors and toxicity were also measured. KEY RESULTS KTP-NH 2, unlike its precursor KTP, was lipophilic and highly analgesic following systemic administration in several acute and chronic pain models, without inducing toxic effects or affecting motor responses and blood pressure. Binding to opioid receptors was minimal. KTP-NH 2 inhibited nociceptive responses of spinal neurons. Its analgesic effects were prevented by intrathecal or i.p. administration of naloxone. CONCLUSIONS AND IMPLICATIONS Amidation allowed KTP to show good analgesic ability after systemic delivery in acute and chronic pain models. The indirect opioid-mediated actions of KTP-NH 2 may explain why this compound retained its analgesic effects although the usual side effects of opioids were absent, which is a desired feature in next-generation pain medications

Crustacean and aquatic insect assemblages in the Mediterranean coastal ecosystems of Empord`a wetlands (NE Iberian peninsula)

Coastal wetlands are characterized by high biodiversity, which is one of the main criteria considered when establishing protection policies or when proposing adequate management actions. In this study, the crustacean and aquatic insect composition of the Empord`a wetlands is described. These two faunal groups contribute highly to the total biodiversity in these wetlands but are seldom considered when managing natural areas. A selection (84 sampling points) of all water body types present in the Empord`a wetlands were sampled monthly (surber and dip net with a 250 μm mesh). Sampling was carried out during 3 surveys (1991-92, 1996-97 and 1999-2000). A rich fauna of 125 crustacean and 295 aquatic insect taxa was identified. We characterized each water body type using the most abundant species and the relative species richness of the taxonomic groups. A classification of the water body types, according to similarity between inventories, groups the brackish and hyperhaline systems in one cluster and the various freshwater systems in another one. Among freshwater systems, lotic waters and freshwater wetlands have a high similarity, whereas rice fields and freshwater springs have a low similarity

Estimation of Water Circulation in a Mediterranean Salt Marsh and its Relationship with Flooding Causes

Variations in water volume in small depressions in Mediterranean salt marshes in Girona (Spain) are described and the potential causes for these variations analysed. Although the basins appear to be endorrheic, groundwater circulation is intense, as estimated from the difference between water volume observed and that expected from the balance precipitation / evaporation. The rate of variation in volume (VR = AV / VAt) may be used to estimate groundwater supply ('circulation'), since direct measurements of this parameter are impossible. Volume.conductivity figures can also be used to estimate the quantity of circulation, and to investigate the origin of water supplied to the system. The relationships between variations in the volume of water in the basins and the main causes of flooding are also analysed. Sea storms, rainfall levels and strong, dry northerly winds are suggested as the main causes of the variations in the volumes of basins. The relative importance assigned to these factors has changed, following the recent regulation of freshwater flows entering the system

Dinámica del heleoplancton en relación a las fluctuaciones hidrológicas en aiguamolls de l’Empordà (NE de la península Ibérica). Propuesta de un método sencillo de monitorización basado en la abundancia de grupos taxonómicos

Monitoring of the 'ecological water quality' in 'Aiguamolls de l’Empordà' Natural Park was carried out between September 1996 and August 1997 . The aim of this sampling programme was to design a simple method for rapid detect changes in water quality due to human activity. These include flow regulation by the Park management, nutrient entries from effluents of a nearby wastewater treatment plant or agricultural fertilising. The proposed method is based on the analysis of the abundance of characteristic taxonomic groups of aquatic invertebrates (heleoplankton). The simplicity of the method is ensured by the use of large taxa which are easier to recognise than species. The functioning of aquatic systems has been modelled by means of correspondence analysis between samples and taxa. Results can be summerized in five environmental conditions with a regular community structure. Dominated by one taxon: cladocerans, ostracods, calanoids, cyclopoids and harpacticoids. The dynamics of both freshwater and brackish lagoons can be modelled as displacements between these five groups of environmental conditions. Nevertheless, the “calanoids situation” and the “harpacticoids situation” occur mainly in brackish lagoons, whereas the “cladocerans situation” occurs mainly in freshwater. The four principal axes of data variation have been respectively identified as nutrient turnover rate, hypertrophy, degree of mineralization of the organic matter and eutrophy. The use of these taxa has been validated by comparison with a model obtained from the species. We conclude that in a highly fluctuating system such as the one here, only persistent situations of eutrophy or hypertrophy must be equated to low 'ecological water quality'