Do urban rivers in the amazon coast trap macroplastic?

Amazon Rivers are important sources of macroplastic that enter the oceans. The estimated macroplastic transport is still inaccurate as hydrodynamics are not considered and data are not collected in situ. The present study shows the first quantification of floating macroplastics at different temporal scales, and an annual transport estimate through urban rivers in the Amazon: the Acará and Guamá Rivers, which discharge into the Guajará Bay. We conducted visual observations of macroplastics (>2.5 cm) in different river discharges and tidal stages, and we measured current intensity and direction in the three rivers. We quantified 3481 floating macroplastics, which varied according to tidal cycle and seasonality. Although connected to and affected by the same tidal regime, the urban estuarine system had an import rate of 12 ton.y-1 through the Guamá River and an export rate of 21.7 ton.y-1 of macroplastics through the Guajará Bay, affected by local hydrodynamics.

Effects of short-term exposure to genistein and overfeeding diet on the neural and retinal progenitor competence of adult zebrafish (Danio rerio).

Neurogenesis is a process that occurs throughout the life of a vertebrate. Among the different factors that may affect the natural occurrence of neurogenesis, obesity seems to decrease the proliferation capacity of progenitor neuronal cells. Conversely, the phytoestrogen genistein is known to attenuate some obesity effects beyond its neuroprotective action. Aiming to improve the understanding of how obesity and genistein trigger an impact on the neural and retinal progenitor competence of adult zebrafish, fish were exposed to genistein (GEN - 2 µg L-1) alone or combined with two dietary groups (control and overfeed - OFD) for up to 9 weeks. Zebrafish were fed once per day with Artemia sp. in the control and GEN (2% of BW, control diet), and three times per day in the OFD and OFD + GEN groups (12% BW, overfeeding diet). To assess obesity induction, BMI, biometric parameters, and PPAR-γ protein were quantified. Afterwards, qRT-PCR and immunohistochemistry were performed to determine the cell proliferation and the presence of stem cells through PCNA and Sox-2. Our findings proved that overfeeding adult zebrafish increased the general growth and induced the development of fatty liver. However, for OFD + GEN, this effect was assuaged through the anti-adipogenic effect of GEN. This finding suggests that phytoestrogens could be beneficial to reduce the negative effects of obesity. Moreover, OF induced negative effects on retinal and brain homeostasis, decreasing the proliferation capacity of progenitor neuronal cells. With regard to retinal progenitor competence, genistein seems to mitigate the negative impacts of obesity, whereas the effects of obesity on the brain were exacerbated by this phytoestrogen which negatively influenced the homeostasis of zebrafish neural progenitor competence. This study highlighted the fact that the effects of phytoestrogens in adult neural progenitor competence are complex and could exhibit dissimilar effects depending on the tissue.

Integrating ecosystem services into sustainable landscape management: A collaborative approach.

The Paiva River is considered one of the least polluted rivers in Europe and its watershed has a high conservation value. However, the Paiva River basin suffers pressures related with recurrent disturbances in land use, such as forest fires, agricultural activities, urbanization and pressures that affect the natural hydromorphological conditions and the continuity of watercourses. Blue and Green Infrastructures (BGINs) emerge to improve biodiversity, sustainability and the supply of ecosystem services while improving socioeconomic aspects. Thus, this article aims to identify priority areas in the basin, for intervention with these infrastructures. For that, a spatial multicriteria decision analysis (MDCA) was carried out according to several data related to the Paiva River Basin. As local politicians and responsible entities for the natural resources management are the main experts on the problems and their possible solutions at the local level, they were involved in this decision-making model. Therefore, these specialized stakeholders did the weighting assignment according to the most or least importance of the same for the work. The map of priority locations to implement BGINs was obtained in the sequel. To the top 5 priority areas, stakeholders attributed the best solutions based on nature. The most recommended BGINs were recovery/maintenance of riparian vegetation and conservation and reforestation of the native forest, both presented in four of the five areas, and introduction of fuel management strips presented in three of the five areas. Thus, we concluded that it is extremely important to include the communities and the competent entities of nature and environment management in scientific projects related to conservation, forming a synergy that makes it possible to combine scientific knowledge with local experience acquired in the field. This project uses a very flexible methodology of local data and can be a great example to be implemented in other hydrographic basins anywhere in the world.

Copper impair autophagy on zebrafish (Danio rerio) gill epithelium.

Copper (Cu) is an essential element for organism's metabolism, being controversially listed as a priority pollutant. Importantly, the toxicity of Cu has been linked to several cell death pathways. Thus, this study aimed to assess if macroautophagic pathways are triggered by Cu in zebrafish gill, the main target of waterborne pollutants. The electron microscopy findings indicated that Cu induced profound impacts on zebrafish gill structure and functions, being this tissue a biomarker sensitive enough to indicate early toxic effects. The findings also support a clear impairment of autophagy, througth the absence of phagossomes and the significant down-regulation mRNA transcript levels of microtubule-associated protein light chain 3 (LC3). The reduction of LC3 levels was often associated to an increase of apoptotic activation, indicating that the inhibition of macroautophagy triggers apoptosis in zebrafish gills. This study highlighted that the autophagic down-regulation might be affected through the activation of other cell death signaling pathway.

Seasonal effect of land use management on gill histopathology of Barbel and Douro Nase in a Portuguese watershed.

The Vilariça River (located in the northeast of Portugal) is inserted in an agricultural basin and it was chosen to replace the spawning grounds for fish, that was lost due to the construction of dams in the Sabor River. Thus, it is essential to study the effect of agricultural practices on water quality and in the health status of fish. The barbel (Luciobarbus bocagei) and Douro nase (Pseudochondrostoma duriense) were the selected species and the work was developed in two seasons (Summer 2016 and Winter 2017). For that, the histopathological changes of fish gill were used as biomarkers, through a semi-quantitative approach that considers the injuries severity. And the water quality assessment criteria followed the methodologies proposed for classifying the status of surface water bodies from Portugal. The current study showed severe histopathological changes in both species and both seasons, and the water was classified as polluted and extremely polluted in Summer and Winter respectively. The pollution in Summer was due to high temperatures, low dissolved oxygen and major concentration of As and Mn, and in Winter is due to the high concentration of Total Suspended Solids, nitrites and Cd. The increase of values of physico-chemical parameters on the water was caused by the less streamflow and excessive agricultural fertilization in Summer which arrive the river by irrigation, and by the erosion of soil particles with heavy metals associated in Winter. Also, the canonical analysis showed that physico-chemical parameters concentrations in Summer justify the major prevalence of aneurism in barbel and exudate in nase and Winter the major prevalence of hypertrophy in barbel. In conclusion, the study showed that the gill injuries of barbel and Douro nase was correlated with the water quality and it is influenced by seasonal agricultural practices and the flow regime.

The impact of freshwater metal concentrations on the severity of histopathological changes in fish gills: A statistical perspective.

The purpose of this study was to relate the severity of histopathological changes in fish gills with changes in metal concentrations of freshwater samples, and to use the relationships as premature warnings of impairment in aquatic fauna populations. The investigated species were the native barbel (Luciobarbus bocagei) and boga (Pseudochondrostoma sp.), and the introduced trout (Oncorhynchus mykiss), collected from 6 northern Portuguese rivers in a total of 249 individuals. The sampling sites have been linked to different ecological status by the official authorities. The sampling has been repeated 4 times to cover different hydrologic and environmental conditions. The analyzed metals were aluminum, arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, lead and zinc. For each fish, 30 filaments of a gill arch were observed in a light microscope, and the histopathological changes evaluated according to a 6-degree gradation scale that combines the extent and severity of each lesion. The relationships between the histopathological and the chemical results were investigated by the non-parametric Goodman Kruskal gamma correlation and Partial Least Squares regression (PLS). The statistical results highlighted the importance of filament epithelium proliferation (FEP) as key biomarker to the toxicity of sub lethal concentrations of metals, because FEP was significantly correlated with all analyzed metals and explained through PLS regression by concentration changes of Cu, Zn, Mn, Cr and As. A refined regression analysis, where histopathological data on the 3 species were processed in separate, revealed that FEP severity is especially sensitive to changes in metal concentrations in boga. Thus, monitoring studies on the ecological status of northern Portuguese rivers would benefit in time and cost if FEP is used as biomarker and boga as species. Naturally, the option for this species depends on the availability of boga individuals along the stream reaches selected for the monitoring programs.

From catchment to fish: Impact of anthropogenic pressures on gill histopathology.

Gill histopathology was investigated in barbel (Luciobarbus bocagei) and nase (Pseudochondrostoma sp.) in sub-catchments of Paiva River (Portugal) located upstream and downstream of a Waste Water Treatment Plant (WWTP). Multivariate statistical analyses were performed to set up correlations between the species sample (n=24) and injury types (8). The results discriminate well edema and vasodilatation between reference (upstream) and disturbed (downstream) samples. Using a watershed model, time series of physico-chemical parameters and heavy metal concentrations were calibrated and validated for the entire Paiva River basin as to investigate the relationship between water quality and the gill histopathology results. Increased concentrations of heavy metal downstream, specifically of zinc and lead, coincided with a higher severity of histopathological alterations in the fish gills. Significant but less evident relationship between water quality parameters and severity of gill injuries in the analyzed fish species were also observed for fecal coliforms, water temperature and manganese. Notwithstanding the location of the samples upstream and downstream of the WWTP, contamination of Paiva River and its effect on gill injuries cannot be disconnected from other punctual and diffuse pollution sources acting in different sectors within the watershed, namely agriculture and forest management. The severity of histopathological alterations in the fish gills reflected differences in the type and concentration of contaminants in Paiva River, and consequently can be viewed as valuable indicator of water quality.

Gill histopathological and oxidative stress evaluation in native fish captured in Portuguese northwestern rivers.

The Northwestern Portuguese region is densely populated and highly industrialized, suffering from high anthropogenic pressure. To assess the biological effect of the several pollutants that are constantly released to the water, a biomarker-based biomonitoring is a promising approach that may provide early-warning signals of pollutants exposure. Fish gill is the first target of pollutants action, thus histopathological and biochemical changes may constitute potential biomarkers. To evaluate this hypothesis, three native fish species (barbel-Luciobarbus bocagei, chub-Squalius carolitertii and nase-Pseudochondrostoma sp.) were sampled in Northwestern Portuguese rivers, the gill histopathological changes were qualitative and quantitatively analyzed and the lipid peroxidation and glutathione-S-transferase activity were determined. A multivariate statistical analysis was performed to establish correlations between these biological responses, environmental variables and ecological status. The quantitative evaluation of the main histopathological changes and oxidative stress responses emphasize the differences, among species, in the responses to the presence of contaminants in water. Discriminant canonical analysis showed that filament epithelium proliferation, necrosis and GST activity were the main contributors to discriminate the ecological status classification. In addition, the results showed that a wide range of environmental factors are influencing fish physiology. In conclusion, the gill biological responses, although not reflecting specific contaminants, can be used as biomarkers of ecosystems perturbation.

Effects of exposure to cadmium on some endocrine parameters in tilapia, Oreochromis niloticus.

The cadmium impact on interrenal and thyroid functions was assessed in tilapia, Oreochromis niloticus. Fish were exposed to 25 mg L(-1) of CdCl(2) during 24, 48, and 96 h. Exposure to 24 and 48 h induced a significant increase in plasma cortisol levels, whereas at 96 h no differences were found. A significant and sustained decrease in plasma T3 concentrations, and an over time increase in plasma glucose, was also found in exposed fish. The results of the current study show that acute exposures to sublethal cadmium concentrations induce changes in endocrine status and carbohydrate metabolism in O. niloticus.

A stereological study of copper toxicity in gills of Oreochromis niloticus.

Stereological methods were used to estimate the volumetric density (V(V)) of the filamentar epithelium (FE, 39%), lamellae (L, 28%), central venous sinus (CVS, 14%), central axis (16%), mucous cells (MC, 2%) and chloride cells (CC, 1%) in the gill filament of control Nile Tilapia. The relative volumes of FE and L, and the relative volumes of CVS and central axis, varied inversely under exposure to copper, with high copper toxic levels declanching a chronic defence mechanism that was, nevertheless, overcome, and low copper toxic levels causing adaptation within a moderate acute phase type of response. Copper also induced a decrease of the V(V) (MC, gill filament) due to reduction of surface MC, despite the marked increase of stem MC at chronic exposure to high copper toxic levels. Diminution of the numerical density of filamentar CC was responsible for the decreased V(V) (CC, gill filament), although lamellar CC significantly increased at chronic exposure to low copper toxic levels. The present results demonstrate that cell relative volumes, mean volumes and numerical densities are dependent on the variations of the FE and L, which without a quantitative approach may be misinterpreted, thus stressing the importance of using stereological tools for analyzing histopathological patterns.

Predicting sporulation events in a bioreactor using an electronic nose.

An electronic nose (EN) based on a non- specific multi-sensor array was used to accurately estimate sporulation events and the spore concentration of Bacillus subtilis cultures. The array included 6 metal oxide sensors (MOS), 10 metal oxide semiconductor field effect transistors (MOSFET), one CO(2) infrared sensor and one humidity sensor. The EN was used to monitor the gas emissions from B. subtilis bioreactions during both batch and fed-batch operation. The signal pattern produced by the sensors was evaluated by principal component analysis (PCA) and training cultivations were used to build a model. The arc length of the PCA trajectories was successfully correlated to the off-line spore count; a strong linear correlation (R(2) = 0.992) between the numerical integration of the curves and the measured spore concentration was established. The fast responses of the sensors in combination with the robust correlation with the off-line determination of spore concentration establish this EN device as a convenient tool for monitoring sporulation events in bioprocesses.

Locally produced survival cytokines IL-15 and IL-7 may be associated to the predominance of CD8+ T cells at heart lesions of human chronic Chagas disease cardiomyopathy.

Human chronic Chagas disease cardiomyopathy (CCC) is an inflammatory-dilated cardiomyopathy occurring years after infection by the protozoan Trypanosoma cruzi. The heart inflammatory infiltrate in CCC shows a 2:1 predominance of CD8(+) in relation to CD4(+) T cells, with a typical Th1-type cytokine profile. However, in vitro expansion of infiltrating T cells from heart biopsy-derived fragments with interleukin-2 (IL-2) and phytohaemagglutinin leads to the outgrowth of CD4(+) over CD8(+) T cells. We hypothesized that survival cytokines, such as IL-2, IL-7 and IL-15 might be differentially involved in the growth and maintenance of heart-infiltrating and peripheral CD8(+) T cells from CCC patients. We found that IL-7 and IL-15 were superior to IL-2 in the expansion and viability of CD8(+) T cells from both PBMC and heart-infiltrating T-cell lines from CCC patients, and the combination of the three cytokines showed synergic effects. Heart-infiltrating CD8(+) T cells showed higher expression of both IL-15R alpha and gamma(c) chain than CD4(+) T cells, which may explain the improvement of CD8(+) T-cell growth in the presence of IL-2 + IL-7 + IL-15. Immunohistochemical identification of IL-15 and the higher mRNA expression of IL-15R alpha, IL-7 and gamma(c) chain in CCC heart tissues compared with control individuals indicate in situ production of survival cytokines and their receptors in CCC hearts. Together, our results suggest that local production of IL-7 and IL-15 may be associated with the maintenance and predominance of CD8(+) T cells, the cells effecting tissue damage in CCC hearts.

CD4+CD25+Foxp3+ indirect alloreactive T cells from renal transplant patients suppress both the direct and indirect pathways of allorecognition.

Alloreactive T cells recognize donor antigens by two routes: direct and indirect pathways of allorecognition. Although the direct pathway is reported to be dominant in allograft rejection, indirect allorecognition also plays an important role. Indirect alloreactivity is also observed in renal transplant patients irrespective of rejection. Previously we showed a predominance of interleukin (IL)-10 induced by indirect allorecognition of donor human leucocyte antigen (HLA)-DR peptides, suggesting the existence of indirect alloreactive T cells displaying regulatory activity. In the present work, our objective was to characterize these regulatory T cells. We detected indirect alloproliferation of peripheral blood mononuclear cells (PBMC) from renal transplant patients, induced by donor HLA-DR peptides, dependent on IL-4 or IL-10, suggesting regulatory activity as part of the alloreactive T-cell repertoire. PBMC-derived indirect alloreactive T-cell lines were established and produced both inflammatory and regulatory cytokines. We showed that two of these T-cell lines which were able to inhibit both direct and indirect alloproliferation of another T-cell line from the same patient presented a CD4(+)CD25(+)Foxp3(+) T-cell population. These data support the idea that indirect alloreactive T cells may also have regulatory activity and may contribute to the maintenance of the human renal allograft.

Alterações histológicas em brânquias de tilápia nilotica Oreochromis niloticus causadas pelo cádmio / Histological alterations in gills of Nile tilapia Oreochromis niloticus caused by cadmium

Os efeitos histopatológicos do cádmio nas brânquias de tilápia Oreochromis niloticus foram estudados por microscopia óptica, usando 25mgl-1 de CdCl2 durante quatro dias, com o objetivo de identificar seus efeitos agudos na estrutura das brânquias. A morfologia geral das brânquias de O. niloticus é idêntica à de outros teleósteos, apresentando quatro pares de arcos branquiais com filamentos bem desenvolvidos. Situadas lateralmente, encontram-se as lamelas provenientes do eixo central dos filamentos. No epitélio filamentar foi possível identificar células de cloro, pavimentosas e mucosas. Os peixes expostos ao cádmio mostraram sinais de lesões epiteliais; edema intersticial, vasodilatação das lamelas, destacamento do epitélio lamelar e proliferação do epitélio filamentar. As alterações observadas também incluíram fusão nas lamelas como resultado de hiperplasia e hipertrofia epitelial, ruptura do sistema de células pilar, aneurismas e necroses.

The histopathogical effects of cadmium on the gills of tilapia Oreochromis niloticus were studied by light microscopy, using 25mgl-1 of CdCl2 during four days to identified the effects of short-term exposure on gills structure. The general morphology of O. niloticus gills is similar to the other teleostean fishes, showing four pairs of gills arches with well developed filaments. Bilaterally situated, secondary lamellae branches are found from the central axis of the filaments. The filamentar epithelium showed the chloride cells, the pavement cells and mucous cells. Fish exposed to cadmium showed signs of epithelial lesion, namely the interstitial edema, swollen of the lamellae, lifting and cellular proliferation of the filamentar epithelium. The changes of the gills also included lamellar fusion as a result of epithelial hyperplasia and hypertrophy, the breakdown of pillar cell system, and aneurisms with some ruptures and necrosis, especially in the filamentar epithelium.

Cellular autoreactivity against heat shock protein 60 in renal transplant patients: peripheral and graft-infiltrating responses.

Autoreactivity to heat shock protein 60 (Hsp60) has been implicated in the pathogenesis and regulation of chronic inflammation, especially in autoimmune diseases. In transplantation, there is a lack of information regarding the cytokine profile and specificity of cells that recognize self-Hsp60 as well as the kinetics of autoreactivity following transplantation. We studied the cellular reactivity of peripheral and graft-infiltrating lymphocytes against Hsp60 in renal transplant patients. Cytokine production induced by this protein in peripheral blood mononuclear cells indicated a predominance of interleukin (IL)-10 during the late post-transplantation period, mainly in response to intermediate and C-terminal peptides. Patients with chronic rejection presented reactivity to Hsp60 with a higher IL-10/interferon (IFN)-gamma ratio compared to long-term clinically stable patients. Graft-infiltrating T cell lines, cocultured with antigen-presenting cells, preferentially produced IL-10 after Hsp60 stimulation. These results suggest that, besides its proinflammatory activity, autoreactivity to Hsp60 in transplantation may also have a regulatory role.

Microcystin-LR promote intestinal secretion of water and electrolytes in rats.

We showed previously that exposure to microcystin-LR causes renal toxic effects in isolated perfused rat kidney, and that inflammatory mediators from supernatants of macrophages stimulated by microcystin-LR are involved in this process. The aim of this research was to examine water and electrolytes secretion in vivo, induced by microcystin-LR and supernatant of macrophages stimulated for this toxin (SUP.MphiS + MCLR), using perfused rat ileal segment and ligated intestinal loop models. We found microcystin-LR at 1 microg/ml (0.09 +/- 0.003* vs. control 0.07 +/- 0.001 g of secretion/2 cm of loop; P < 0.05*) and the SUP.MphiS + MCLR after 18 h postinoculation (0.10 +/- 0.003 vs. control 0.03 +/- 0.002 g/cm) caused intestinal secretion. In addition, microcystin-LR caused significant sodium secretion (-2.18 +/- 0.72* vs. control 2.18 +/- 0.50 microEq g(-1) min(-1)), potassium (-0.26 +/- 0.04* vs. control 0.32 +/- 0.03 microEq g(-1) min(-1)), chloride (MCLR = -3.29 +/- 1.93* vs. control 0.88 +/- 1.25 microEq g(-1) min(-1)) and water (-0.012 +/- 0.004* vs. control 0.002 +/- 0.002 ml g(-1) min(-1)). We also demonstrated SUP.MphiS + MCLR to induce intestinal secretion of electrolytes (sodium, potassium, chloride) and water. These findings suggested that microcystin-LR and lamina propria macrophages-derived mediators are able to induce intestinal secretion in vivo, probably via inhibition of protein phosphatase.

Intestinal barrier function and secretion in methotrexate-induced rat intestinal mucositis.

Chemotherapy-induced mucositis is an important dose-limiting and costly side effect for which there is no definitive prophylaxis or treatment. This is due in part to the lack of understanding of its pathophysiology and impact on intestinal function. The objectives of this study were to investigate the small intestine barrier function and electrolyte and water transport in an experimental model of methotrexate-induced mucositis, and to correlate these alterations with histological damage. Wistar rats were treated with methotrexate (1.5-3.5 mg/kg) for 3 days to induce mucositis. Intestinal permeability was measured by the urinary excretion rate of lactulose and mannitol following administration by gavage. Intestinal perfusion was performed in vivo for evaluation of water and electrolyte transports. Methotrexate-treated rats lost a significant amount of weight and presented a marked reduction in food intake. Methotrexate induced significant and dose-dependent villous atrophy and elongation of crypts in duodenum, jejunum, and ileum. Methotrexate also induced an increase in sodium and potassium secretion and an important reduction of the mucosa absorptive surface area, shown by the decrease in the mannitol excretion ratio. In conclusion, methotrexate caused major changes in small bowel function by disrupting intestinal permeability and inducing electrolyte secretion in parallel with substantial histological damage.