Vertical distribution and trophic structure of the macrozooplankton in a shallow temperate estuary (Ria de Aveiro, Portugal)

The zooplankton of the lower part of Canal de Mira (Ria de Aveiro) was sampled during one lunar month. The sampling programme consisted of nine 25 hour fixed-cycles, separated weekly. In each cycle, samples were collected every two hours at three depths (surface, mid-water and above the bottom) with a 500 µm mesh net. The overall effect of the tidal phase was analyzed, taking into account the day and depth of the vertical position of the organisms through a 3-way analysis of variance (ANOVA). The zooplankton densities were, in general, higher at the surface during the night and near the bottom during the day, mainly at spring tide. The variation in the number of species followed a similar pattern to that observed for abundance. Significant differences (p<0.01) between diel and tidal phases were observed. Interaction between phase of the day and depth was also significant (p<0.05), with higher organism densities observed during night periods near the bottom. From a trophic point of view the zooplankton community of Canal de Mira was mainly composed of carnivorous and omnivorous species. Carnivores were significantly more abundant around the new and full moon (p<0.001), the omnivores at the new moon (p<0.001) and the herbivores and detritivores at the first quarter of the moon cycles (p<0.001). The density of carnivores was significantly higher at the surface at night and near the bottom during the day (p<0.05). Significant differences in the abundance of omnivores were observed between phases of the day and between depths, with higher values near the bottom during the day. The herbivores and detritivores had significantly higher densities during flood tides (p<0.001).DISTIBUICIÓN VERTICAL Y ESTRUCTURA TRÓFICA DEL MACROZOOPLANCTON EN UN ESTUARIO TEMPLADO (RIA DE AVEIRO). – El zooplancton de la parte inferior del Canal de Mira (Ria de Aveiro) fue muestreado durante un mes lunar. El programa de muestreo consistió en nueve ciclos de 25 horas, con periodicidad semanal. En cada ciclo, las muestras fueron recogidas cada dos horas, a tres profundidades (superficie, columna de agua y sobre el fondo) con una red de 500 µm. El efecto total de la fase de la marea fue analizado, teniendo en consideración el día y la profundidad en la posición vertical de los organismos con un análisis 3-Way ANOVA. Las densidades del zooplancton fueron en general más altas en la superficie durante la noche y cercanas al fondo durante el día, principalmente em la marea viva. La variación en el número de especies siguió un patrón similar al observado para la abundancia. Se observaron diferencias significativas (p<0.01) entre las fases del día y las fases de marea. La interacción entre la fase del día y la profundidad fue también significativa (p<0.05) con densidades de organismos más altas durante los periodos nocturnos en el fondo. De un punto de vista trófico, la comunidad zooplanctónica del Canal de Mira está principalmente compuesta por especies carnívoras y omnívoras. Los carnívoros fueram significativamente más abundantes cerca de la luna nueva y de la luna llena (p<0.001), los omnívoros en la luna nueva (p<0.001) y los herbívoros e detritívoros en el primero cuarto de los ciclos de la luna (p<0.001). La densidad de los carní- voros fue significativamente más alta en la superficie durante la noche y en el fondo durante el día (p<0.05). Para los omní- voros, fueron observadas diferencias significativas entre las fases del día y la profundidad, registando valores más elevados en el fondo durante el día. Los herbívoros y los detritívoros presentaron densidades significativamente superiores durante los ciclos de marea (p<0.001)

Deliriumin the ICU setting ‐ a subjective and theoretical survey before the implementation of the Confusion Assessment Method for the ICU in an unit

Background and Goal of Study: The current definition of delirium comprises acute change or fluctuation in mental status and inattention, accompanied by either altered level of consciousness or disorganized thinking. It is a frequent condition in the ICU and it is associated with longer hospital stay, increase in mortality at 6 months and long-term cognitive impairment, but remains under diagnosed. The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) has been validated and implemented in many ICUs and its use is recommended by the Society of Critical Care Medicine. It is our purpose to evaluate the individual perspective and the objective knowledge of our staf f about delirium before the implementation of the CAM-ICU. Materials and Methods: Anonymous survey to our ICU clinical staf f which contained subjective and ‘true or false’ questions. Data was analised with the sof tware SPSS version 17.0. The Wilcoxon test was used to compare autoperception of knowledge about delirium and the content of answers regarding its definiton. Results: Forty two questionnaires were returned (participation rate of 73%), 11 from physicians and 31 from nurses. Overall, 61,9% of inquiries think they can give a definition for delirium in the ICU and 50% claim to be able to evaluate delirium. 28,6% of the respondents - 63,6% of the physicians and 16,1% of the nurses - know the CAM-ICU. From these only a quarter has received education on this method, 75% think it’s easy to apply and 66% don’t see its use as an increase in the daily workload. We found a high rate of wrong and ‘I don’t know’ answers to questions about operationalization, diagnosis and outcome. The subjects’ auto-perception on their knowledge about delirium [Likert scale] was compared to their ability to answer questions related to its definiton - ‘attention deficit is essencial for diagnosis’ [true], Wilcoxon test Z=-4,699 (p< 0,001); ‘disorganized thinking is essential for diagnosis’ [false], Wilcoxon test Z=-4,437 (p< 0,001). Conclusions: The respondents’ auto perception of knowledge about delirium doesn’t translate in the ability of giving an appropriate definition and making an adequate evaluation. Most of the inquiries don’t know the CAM-ICU, but those who do believe it’s easy to apply and its use won’t increase the workload. We performed educational sessions about delirium and the CAM-ICU in our unit to encourage our clinical staf f to deal properly with this hazardous condition

Effects of triclosan on early development of Solea senegalensis: from biochemical to individual level

Harmful effects of triclosan (TCS) have been reported on several organisms; however, effects on early life stages of marine vertebrates are limited. Therefore, the objective of this work was to assess the effects of TCS during early development of the flatfish Solea senegalensis after initial characterization of cholinesterases (ChEs) and determination of selected biochemical markers baseline levels. Characterization of ChEs and determination of biochemical markers baseline levels of cholinergic activity, energy metabolism and oxidative stress were analysed in sole at 3 days after hatching (dah) and at the onset and end of metamorphosis. To assess TCS effects, fish were exposed during 96h to 30-500 μg L-1 TCS until 3 dah. Fish at 13 dah were exposed during 48h to 200-1,500 μg L-1 TCS and maintained until complete metamorphosis. Effects on survival, malformations, length, metamorphosis progression and biochemical markers were evaluated. The main ChE active form present in sole early life stages is acetylcholinesterase and baseline levels of oxidative stress and energy metabolism biomarkers changed according to fish developmental stage. Triclosan induced malformations (EC50 = 180 μg L-1 at 3 dah), decreased growth (95 μg L-1 at 3 dah; 548 μg L-1 at 24 dah) and affected metamorphosis progression (391 μg L-1 at 17 dah). Impairment of antioxidant system was observed, with TCS affecting catalase at the end of metamorphosis test, however, no oxidative damage on lipids was detected. Glutathione S-transferase was the most sensitive endpoint during early larval test (LOEC = 30 μg L-1). Exposure to TCS affected S. senegalensis at individual and sub-individual levels, both at early larval stage and during the critical period of metamorphosis.publishe

An integrated approach to assess the sublethal effects of colloidal gold nanorods in tadpoles of Xenopus laevis

Gold nanorods (AuNR) have been explored for many applications, including innovative nanomedicines, which also might contribute to its increase in the environment, namely due to inadequate disposable of wastes into aquatic environments. Early-life stages of amphibians are usually aquatic and sensitive to chemical contamination. Accordingly, this study aimed to determine the sublethal effects of CTAB functionalized AuNR on Xenopus laevis tadpoles. As such, tadpoles were exposed to serial concentrations of AuNR for 72 h. A reduction in the rate of feeding (EC50 = 4 μg.L-1), snout to vent growth (EC50 = 5 μg.L-1) and weight gain (EC50 = 6 μg.L-1), was observed for AuNR-exposed tadpoles. Also, tadpoles actively avoided concentrations ≥ 4 μg.L-1 of AuNR, after 12 h of exposure. At the biochemical level, AuNR caused impairments in antioxidant and nervous system related enzymes. Exposure to CTAB alone caused a high mortality. Results indicated that CTAB functionalized AuNR may induce several sublethal effects that may compromise the organism's fitness. Avoidance behavior (which corresponds to the disappearance of organisms, thus, similar to their death), observed at concentrations matching those inducing sublethal effects, suggest that it should be considered in the risk assessment for amphibians.publishe

Host-microbe-drug-nutrient screen identifies bacterial effectors of metformin therapy

Metformin is the first-line therapy for treating type-2 diabetes and a promising anti-aging drug. We set out to address the fundamental question of how gut microbes and nutrition, key regulators of host physiology, impact the effects of metformin. Combining two tractable genetic models, the bacterium E. coli and the nematode C. elegans, we developed a high-throughput four-way screen to define the underlying host-microbe-drug-nutrient interactions. We show that microbes integrate cues from metformin and the diet through the phosphotransferase signalling pathway that converges on the transcriptional regulator Crp. A detailed experimental characterization of metformin effects downstream of Crp in combination with metabolic modelling of the microbiota in metformin-treated type-2 diabetic patients predicts the production of microbial agmatine, a regulator of metformin effects on host lipid metabolism and lifespan. Our high-throughput screening platform paves the way for identifying exploitable drug-nutrient-microbiome interactions to improve host health and longevity through targeted microbiome therapie

Effects of the essential metals copper and zinc in two freshwater detritivores species: biochemical approach

The input of metals into freshwater ecosystems from natural and anthropogenic sources impairs water quality and can lead to biological alterations in organisms and plants, compromising the structure and the function of these ecosystems. Biochemical biomarkers may provide early detection of exposure to contaminants and indicate potential effects at higher levels of biological organisation. The effects of 48 h exposures to copper and zinc on Atyaephyra desmarestii and Echinogammarus meridionalis were evaluated with a battery of biomarkers of oxidative stress and the determination of ingestion rates. The results showed different responses of biomarkers between species and each metal. Copper inhibited the enzymatic defence system of both species without signs of oxidative damage. Zinc induced the defence system in E. meriodionalis with no evidence of oxidative damage. However, in A. desmarestii exposed to zinc was observed oxidative damage. In addition, only zinc had significantly reduced the ingestion rate and just for E. meridionalis. The value of the integrated biomarkers response increased with concentration of both metals, which indicates that might be a valuable tool to interpretation of data as a whole, as different parameters have different weight according to type of exposure

UV-B Filter Octylmethoxycinnamate Induces Vasorelaxation by Ca2+ Channel Inhibition and Guanylyl Cyclase Activation in Human Umbilical Arteries

Ultraviolet (UV) filters are chemicals widely used in personal care products (PCPs). Due to their effect as endocrine disruptor compounds (EDCs), the toxicity of UV filters is a current concern for human health. EDC exposure may be correlated to cardiovascular diseases (CVD), but to our knowledge, no studies assessed the UV filters effects as human EDCs at the vascular level. Octylmethoxycinnamate (OMC) is the world&rsquo;s most widely used UV-B filter, present in more than 90% of PCPs. Due to its demonstrated multiple hormonal activities in animal models, this substance is also suspected to be a human EDC. The purpose of this study was to assess the rapid/short-term effects of OMC on arterial tonus and analyse its mode of action (MOA). Using human umbilical arteries, the endocrine effects of OMC were evaluated in in vitro (cellular and organ) experiments by planar cell surface area (PCSA) and organ bath, respectively. Our data show that OMC induces a rapid/short-term smooth muscle relaxation acting through an endothelium-independent MOA, which seems to be shared with oestrogens, involving an activation of soluble guanylyl cyclase (sGC) that increases the cyclic guanosine monophosphate (cGMP) intracellular levels and an inhibition of L-type voltage-operated Ca2+ channels (L-Type VOCC)

Characterization of the cholinesterases present in head tissues of the estuarine fish Pomatoschistus microps: Application to biomonitoring

In recent years biomarkers have been widely used for the assessment of effects and/or exposure to environmental contaminants. One of the most frequently used biomarkers is the inhibition of cholinesterases (ChE), which is a useful indicator of organophosphate and carbamate exposure and/or effects. Recent studies indicated that more than one ChE may be present in tissues of fish and that different forms may vary in their sensitivity to anticholinesterase agents. Cholinesterase activity of the juvenile of the common goby (Pomatoschistus microps), a widespread fish in estuaries of the Atlantic coast of northwestern Europe, was characterized using four substrates (acetylthiocholine iodide, acetyl-beta-metylthiocholine iodide, propionylthiocholine iodide, and S-butyrylthiocholine iodide) and three ChE inhibitors (eserine sulfate, BW284C51, and iso-OMPA) in different tissues of the fish head. In addition, the range of ChE activity that may be considered as "normal" for non-exposed P. microps was determined. The results suggest the presence of two types of ChE in the whole-head homogenate. The present study underscores the relevance of ChE characterization before its use as a biomarker in biomonitoring studies. (c) 2005 Elsevier Inc. All rights reserved.FCTCONTROL project - PDCTM/C/MAR/15266/1999RISKA project - FCT/POCTI/BSE/46225/2002EU/FEDE