Trace elements accumulation in the sea lamprey along the major hydrographic basins of Portugal

Trace elements accumulation in the sea lamprey along the major hydrographic basins of Portuga

Clear-water scour at comparatively large cylindrical piers

New long-duration clear-water scour data were collected at single cylindrical piers with the objective of investigating the effect of sediment coarseness, Dp=D50 (Dp = pier diameter; D50 = median grain size) on the equilibrium scour depth and improving the scour depth time evolution modeling by making use of the exponential function suggested in the literature. Experiments were carried out for the flow intensity close to the threshold condition of initiation of sediment motion, imposing wide changes of sediment coarseness and flow shallowness, d=Dp (d = approach flow depth). The effect of sediment coarseness on the equilibrium scour depth was identified; existing predictors were modified to incorporate this effect for U=Uc ≈ 1.0; Dp=D50 > ≈60 and d=Dp ≥ 0.5; the complete characterization of a known scour depth time evolution model was achieved for U=Uc ≈ 1.0, 60 < Dp=D50 < 500 and 0.5 ≤ d=Dp ≤ 5.0

Structural lipid changes and Na+/K+-ATPase activity of gill cells'basolateral membranes during saltwater acclimation in sea lamprey (Petromyzon marinus, L.) juveniles

Seawater acclimation is a critical period for anadromous species and a process yet to be understood in lampreys. Considering that changes in lipid composition of the gill cells' basolateral membranes may disrupt the major transporter Na+K+-ATPase, the goal of this study was to detect changes at this level during juvenile sea lamprey seawater acclimation. The results showed that saltwater acclimation has a direct effect on the fatty acid composition of gill cells basolateral membrane's phospholipids. When held in full-strength seawater, the fatty acid profile of basolateral membrane's phospholipids suffered a restructure by increasing either saturation or the ratio between oleic acid and eicosapentaenoic acid. Simultaneously, the activity of Na+K+- 2 ATPase revealed a significant and positive correlation with basolateral membrane's cholesterol content in the presence of highest salinity. Our results pointed out for lipid adjustments involving the functional transporter present on the gill cell basolateral membranes to ensure the role played by branchial Na+K+-ATPase in ion transport during saltwater acclimation process. The responses observed contributed to the strategy adopted by gill cell's basolateral membranes to compensate for osmotic and ionic stressors, to ensure the success of the process of seawater acclimation associated with the downstream trophic migration of juvenile sea lamprey.This work was financially supported by the Foundation for Science and Technology (FCT) project PTDC/BIA-BEC/103258/2008 and project UID/MAR/04292/2013 (national funds FCT/MEC–PIDDAC through Acordo de Parceria PT2020)

Comparison of 2.3 & 5 mega pixel (MP) resolution monitors when detecting mammography image blurring

Background - Image blurring in Full Field Digital Mammography (FFDM) is reported to be a problem within many UK breast screening units resulting in significant proportion of technical repeats/recalls. Our study investigates monitors of differing pixel resolution, and whether there is a difference in blurring detection between a 2.3 MP technical review monitor and a 5MP standard reporting monitor. Methods - Simulation software was created to induce different magnitudes of blur on 20 artifact free FFDM screening images. 120 blurred and non-blurred images were randomized and displayed on the 2.3 and 5MP monitors; they were reviewed by 28 trained observers. Monitors were calibrated to the DICOM Grayscale Standard Display Function. T-test was used to determine whether significant differences exist in blurring detection between the monitors. Results - The blurring detection rate on the 2.3MP monitor for 0.2, 0.4, 0.6, 0.8 and 1 mm blur was 46, 59, 66, 77and 78% respectively; and on the 5MP monitor 44, 70, 83 , 96 and 98%. All the non-motion images were identified correctly. A statistical difference (p <0.01) in the blurring detection rate between the two monitors was demonstrated. Conclusions - Given the results of this study and knowing that monitors as low as 1 MP are used in clinical practice, we speculate that technical recall/repeat rates because of blurring could be reduced if higher resolution monitors are used for technical review at the time of imaging. Further work is needed to determine monitor minimum specification for visual blurring detection

Can heart tissue fatty acid profile be used as a tool to discriminate sea lamprey (Petromyzon marinus, L.) populations in several Portuguese river basins?

This study proposes to evaluate the use of heart tissue fatty acid signature and multivariate analysis of fatty acid profile as a possible discriminating tool for sea lamprey P. marinus populations sampled in Portuguese river basins. Local fisherman collected adult sea lampreys in eight Portuguese river basins (Minho, Lima, Cávado, Douro, Vouga, Mondego, Tagus and Guadiana) at the beginning of their spawning migration. Heart total lipid extraction was obtained by accelerated solvent extraction (ASE) and FAMEs were prepared by transesterification with methanol-boron trifluoride and analysed by GC. FAMEs were identified by comparison of their retention times with known standards chromatographed in identical gas chromatography conditions. The fatty acid profile of the heart tissue varied among the individuals of the different river basins. In order to identify which fatty acid contributed most to the differences between river basins heart tissue, MDA was employed. The MDA proved to be statistically significant and the overall corrected classification rate estimated from cross-validation procedure was 86.2%. Although in the case of the individuals of Tagus and Guadiana 100% and 94.7 % of subjects were correctly classified, respectively, there are always a few individuals of the other 5 watersheds that have characteristics identical to those observed in these two river basins.The results are discussed in terms of fatty acid origin and hypothesis concerning the migratory behavior that could lead to these results. The fatty acid profile of heart is considered more stable than other organs, but it still exhibits some variability. This study seems to point out the potential for fatty acid compositions to discriminate sea lampreys from Portuguese river basins, which are probably related with environmental variables that they may have been exposed during early stages of their life cycle

Can the mitochondrial malondialdehyde content be an useful tool to distinguish ecological quality of Petromyzon marinus habitat?

The sea lamprey is an anadromous species that migrates twice during its life cycle between freshwater and seawater. Microphagous larvae generally spend 4–5 years burrowed in the substrate of rivers and streams before undergoing metamorphosis that ends with the beginning of the juvenile trophic migration. Once metamorphosis is complete, sea lamprey juvenile downstream migrants are fully tolerant to 35 PSU seawater. Pollution resulting from industrial effluents may disturb the seawater acclimatization causing oxidative damages, and ultimately may lead to a decrease of sea lamprey population. The aim of this study was to compare salt acclimation of sea lamprey juveniles captured in river basins with different levels of aquatic pollution, using mitochondrial glutathione and malondialdehyde of gills and liver as markers of physiological stress and cell damages. The results showed that juveniles from Lima basin exhibited the highest levels of mitochondrial malondialdehyde in gills, even though significant changes in the stress markers of mitochondrial gills of all animals subject to salt acclimation were not detected. In addition, an increase in the oxidative damages of hepatic mitochondria of macrophthalmia from Vouga basin suggests the occurrence of metabolic failures with the potential to disturb the capacity to adaptation to the marine environment

Hepatic mitochondrial content in malondialdehyde may be a marker of sea lamprey contact with atrazine

The atrazine attracts special attention as pollutant because of itspersistence in the aquatic environment. Although this herbicide has been studied in teleost, its toxicity in the sea lamprey, Petromyzon marinus is still poorly understood. Oxidative stress may occur if chemical pollutants contribute to block the capacity of mitochondria to generate ATP with continuous production of reactive oxygen species (ROS), disturbing the success of P. marinus seawater acclimation. So, the aim of this study was to evaluate how atrazine influences the malondialdehyde (MDA), glutathione (GSH) and glutathione disulfide (GSSG) contents of gills and liver mitochondria of juveniles from Lima river basin, Portugal during salt acclimation. Sampling occurred at the beginning of the P. marinus downstream migration. The sampled juveniles were transported alive to the laboratory and maintained in 200 l tanks with LSS 8 life support system. Two groups of 40 specimens were hold in tanks with 50 or 100 lg/l atrazine, during 30 days. The salinity was gradually increased from 0 to 35 psu,following a three step procedure during a 30 days period. The control group was maintained in freshwater without atrazine. Mitochondria obtained by centrifugation at 15000 g, 30 min, 4°C, of tissues homogenates prepared in 50 mM Tris-HCl pH 7.5 buffer were used in determination of ROS, MDA, GSH and GSSG by fluorescence. The statistical analysis were performed by ANOVA I and Duncan (p < 0.05), using SPSS 22 for Windows.The results showed that in P. marinus juveniles, no significant changes in the markers of oxidative stress and cell damages were detected in the mitochondrial gills. Nevertheless, in the animals exposed to 50 lg/l atrazine the content in glutathione and GSSG increased. A similar pattern of stress markers was detected in hepatic mitochondria. However, in the presence of atrazine, the MDA level of the mitochondria of liver increased threefold in the animals during salt acclimation. The high level of mitochondrial damages, detected in the hepatic mitochondria of macrophthalmia treated with atrazine, suggests that herbicide exposure caused metabolic failures which can disturb the adaptation of these specimens to the oceanic feeding phase. The hepatic mitochondrial MDA levels of P. marinus, may eventually detect sea lamprey contact with chlorine herbicides

Assessment of microbiota present on a Portuguese historical stone convent using high-throughput sequencing approaches

The study performed on the stone materials from the Convent of Christ revealed the presence of a complex microbial ecosystem, emphasizing the determinant role of microorganisms on the biodecay of this built cultural heritage. In this case study, the presence of Rubrobacter sp., Arthrobacter sp., Roseomonas sp., and Marinobacter sp. seems to be responsible for colored stains and biofilm formation while Ulocladium sp., Cladosporium sp., and Dirina sp. may be related to structural damages. The implementation of high-throughput sequencing approaches on the Convent of Christ's biodecay assessment allowed us to explore, compare, and characterize the microbial communities, overcoming the limitations of culture-dependent techniques, which only identify the cultivable population. The application of these different tools and insights gave us a panoramic view of the microbiota thriving on the Convent of Christ and signalize the main biodeteriogenic agents acting on the biodecay of stone materials. This finding highlighted the importance of performing metagenomic studies due to the improvements and the reduced amount of sample DNA needed, promoting a deeper and more detailed knowledge of the microbiota present on these dynamic repositories that support microbial life. This will further enable us to perform prospective studies in quarry and applied stone context, monitoring biogenic and nonbiogenic agents, and also to define long-term mitigation strategies to prevent biodegradation/biodeterioration processes

Salinity and Atrazine Sublethal Levels Induce Gill Cells Basolateral Membrane Phospholipids Modulation in Sea Lamprey Downstream Migrants

Conditions experienced by anadromous fishes while in freshwater may be critical to their subsequent survival in the sea. During the trophic migration to the ocean, juveniles of sea lamprey (Petromyzon marinus L.) are exposed to several stress factors, including different types of pollutants. We analyzed gill histopathological biomarkers, characterized the lipid profile of the basolateral membrane (BLM) of gill cells, and determined NKA activity, in order to evaluate if BLM lipid profile system plays a part in modulation of NKA activity and may be involved in the successful acclimation of sea lamprey juveniles during downstream migration

Light and myopia: from epidemiological studies to neurobiological mechanisms

Myopia is far beyond its inconvenience and represents a true, highly prevalent, sight-threatening ocular condition, especially in Asia. Without adequate interventions, the current epidemic of myopia is projected to affect 50% of the world population by 2050, becoming the leading cause of irreversible blindness. Although blurred vision, the predominant symptom of myopia, can be improved by contact lenses, glasses, or refractive surgery, corrected myopia, particularly high myopia, still carries the risk of secondary blinding complications such as glaucoma, myopic maculopathy, and retinal detachment, prompting the need for prevention. Epidemiological studies have reported an association between outdoor time and myopia prevention in children. The protective effect of time spent outdoors could be due to the unique characteristics (intensity, spectral distribution, temporal pattern, etc.) of sunlight that is lacking in artificial lighting. Concomitantly, studies in animal models have highlighted the efficacy of light and its components in delaying or even stopping the development of myopia and endeavoured to elucidate possible mechanisms involved in this process. In this narrative review, we (1) summarize the current knowledge concerning light modulation of ocular growth and refractive error development based on studies in human and animal models, (2) summarize potential neurobiological mechanisms involved in the effects of light on ocular growth and emmetropization and (3) highlight a potential pathway for the translational development of noninvasive light-therapy strategies for myopia prevention in children.info:eu-repo/semantics/publishedVersio