Influence of the Use of Irrigation Solution Inhibitors in Improving Dentine Adhesion: A Systematic Review and Meta-Analysis.

INTRODUCTION: This systematic review examined the effect of neutralizing agents on bond strength after irrigation with sodium hypochlorite and their existing protocols in literature. METHODS: This present study adhered to the PRISMA guidelines and was registered at PROSPERO. Five electronic databases were searched (sept-2020/jan-2021) in English, Spanish, and Portuguese, without any restrictions on publication date. Cases reports, editorials and literature reviews were not included. The risk of bias was assessed using the Cochrane Collaboration tool. From the initial 7,147 studies, 2,745 were removed as duplicates and 4,382 were excluded after a title/abstract screen. RESULTS: Seventeen in vitro studies were included. The results showed that the higher the concentration of sodium hypochlorite, the lower the bond strength at dentine/restoration interface (p⟨0.01). Among the studies, sodium ascorbate was the most widely used neutralizer and showed the most significant results in increasing bond strength (p⟨0.01). The bond strength values were found to increase with longer application time of the neutralizing substances (p⟨0.01). CONCLUSIONS: The use of sodium ascorbate as a neutralizing agent can reverse the negative effects of the sodium hypochlorite and improve the bond strength between dentine and resin cement, however, it isn't possible to determine the best protocol for use.

96-well microtiter plates for biofouling simulation in biomedical settings.

Microtiter plates with 96 wells are routinely used in biofilm research mainly because they enable high-throughput assays. These platforms are used in a variety of conditions ranging from static to dynamic operation using different shaking frequencies and orbital diameters. The main goals of this work were to assess the influence of nutrient concentration and flow conditions on biofilm formation by Escherichia coli in microtiter plates and to define the operational conditions to be used in order to simulate relevant biomedical scenarios. Assays were performed in static mode and in incubators with distinct orbital diameters using different concentrations of glucose, peptone and yeast extract. Computational fluid dynamics (CFD) was used to simulate the flow inside the wells for shaking frequencies ranging from 50 to 200 rpm and orbital diameters from 25 to 100 mm. Higher glucose concentrations enhanced adhesion of E. coli in the first 24 h, but variation in peptone and yeast extract concentration had no significant impact on biofilm formation. Numerical simulations indicate that 96-well microtiter plates can be used to simulate a variety of biomedical scenarios if the operating conditions are carefully set.

Fish reproductive guilds downstream of dams.

Fish reproductive guilds were used to evaluate the responses of species with different reproductive strategies during two different periods of post-dam construction. The data used for the comparisons were collected in the upper Paraná River floodplain (Brazil), downstream of the Porto Primavera dam, 2 and 10 years after impoundment. The abundance (catch per unit effort, CPUE), species richness, evenness and structure of communities, all within reproductive guilds, were used to test the hypothesis that these metrics vary spatially and temporally. The influence of damming on species structure and the diversity of fish reproductive guilds varied spatiotemporally, and species with opportunistic reproductive strategies tended to be less affected. Conversely, long-distance migratory species responded more markedly to spatiotemporal variations, indicating that the ecosystem dynamics exert greater effects on populations of these species. Thus, the effects of a dam, even if attenuated, may extend over several years, especially downstream. This finding emphasizes the importance of maintaining large undammed tributaries downstream of reservoirs.

Stress responses of the endemic freshwater cururu stingray (Potamotrygon cf. histrix) during transportation in the Amazon region of the Rio Negro.

Potamotrygon cf. histrix (cururu stingray) are endemic freshwater stingrays from the middle region of the Rio Negro in the Brazilian Amazon basin and are exported worldwide as ornamentals caught by artisanal fishermen. The transport process from capture to final destination is long and stressful. This study quantified stress related changes in corticosterone, blood and water samples (baseline, pre-transport, 3h, 12h and 24h) analyzed during a transport experiment which tested two water additives (tetracycline and the probiotic Efinol). There was a significant stepwise increase in corticosterone levels in stingrays over transport time in combination with osmoregulatory disturbances suggesting a stress related role of this corticosteroid. There were significant increases in water conductivity, Na(+) and K(+) losses and ammonia excretion. Blood parameters such as glucose, hematocrit, red blood count and urea did not change significantly during the experiment. Glucose levels did not increase significantly during transport and this may be due to the fact that other elasmobranchs have been shown to rely more on ketone bodies for energy rather than glucose and produce ammonia as their main nitrogenous waste. The mineralocorticoid action of this hormone has been shown in elasmobranchs and most likely plays a role in osmotic homeostasis. The use of probiotic and especially antibiotic should be avoided since no beneficial effects were observed.

Do river basins influence the composition of functional traits of fish assemblages in Neotropical reservoirs?

In aquatic environments, dams are considered one of the main threats to fish species, acting as an environmental filter for certain functional traits. Although there is some predictability in the composition of the functional traits in reservoirs, it is hypothesized that the environmental filters imposed by evolutionary processes, linked to the characteristics of the basins, are determinant for the functional composition of the traits in reservoirs. For this we performed a PCoA using the functional traits composition matrix of the reservoirs. We used PERMANOVA to test the difference in functional composition between basins. We performed the same process for the species composition matrix to compare the patterns. In this study, there were taxonomic and functional differences among reservoirs inserted in different basins. It was observed that the basin is a determining factor for the functional structure of fish assemblage in reservoirs. When compared, functional and taxonomic structures follow the same pattern, although functionally the reservoir tends to be more similar. These results reinforce the idea that reservoirs act as filters for functional traits (e.g., related with reproduction, feeding and habitat use), although there is a great influence of evolutionary processes related to the basin's characteristics and origin of the ichthyofaunistic province.

The potential advantages of using a poly(HPMA) brush in urinary catheters: effects on biofilm cells and architecture.

Infections related to bacterial colonization of medical devices are a growing concern given the socio-economical impacts in healthcare systems. Colonization of a device surface with bacteria usually triggers the development of a biofilm, which is more difficult to eradicate than free-floating or adhered bacteria and can act as a reservoir for subsequent infections. Biofilms often harbor Viable but nonculturable (VBNC) cells that are likely to be more resistant to antibiotic treatment and that can become active in more favorable conditions causing infection. Biofilm formation is dependent on different factors, chiefly the properties of the surface and of the surrounding medium, and the hydrodynamic conditions. In this work, the antifouling performance of a poly[N-(2-hydroxypropyl) methacrylamide] (poly(HPMA)) brush was evaluated in vitro in conditions that mimic a urinary catheter using Escherichia coli as a model organism. The results obtained with the brush were compared to those obtained with two control surfaces, polydimethylsiloxane (PDMS) (the most common material for catheters) and glass. A decrease in initial adhesion and surface coverage was observed on the brush. This antifouling behavior was maintained during biofilm maturation and even in a simulated post-bladder infection period when the reduction in total cell number reached 87 %. Biofilms were shown to adapt their architecture during that period and VBNC cells adsorbed weakly on the brushes and were completely washed away. Taken together, these results suggest that the use of the poly(HPMA) brush in urinary tract devices such as catheters and stents may reduce biofilm formation and possibly render the formed biofilms more susceptible to antibiotic treatment and with reduced infectivity potential.

Genotoxicity effects on Geophagus brasiliensis fish exposed to Doce River water after the environmental disaster in the city of Mariana, MG, Brazil.

The Doce River basin has suffered the largest environmental accident ever occurred in Brazil with the influx of tailings from Fundão and Santarém, belonging to Samarco mining company, due to the disaster in Mariana. A spill between 50 and 60 million m3 of tailings was estimated by the company. According to Samarco, the wastewater was composed mainly of clay, silt and heavy metals like iron, copper and manganese. Thereby, the objective of the present study was evaluated the genotoxic damage in juvenile of Geophagus brasiliensis (Quoy e Gaimard, 1824) exposed to Doce river water before (DRWBA - Doce River water before acident) and after (DRWAA - Doce River water after acident) the influx of tailings from the Germano and Santarém Dam disasters in Mariana, MG, Brazil. For this, 24 individuals of the species G. brasiliensis (obtained on IFES/ALEGRE fish culture) were submitted to a bioassay with three treatments and eight replicates. The treatments were: 1) Control water (water from the urban water supply system, filtered with a 0.45 µm membrane), 2) DRBA and 3) DRAA. After 96 h, these fishes were anesthetized to remove blood for evaluation of genotoxic damage (micronucleus and comet). For the bioassay, a total of 80 L of The Doce River water were collected before the influx of tailings and after the influx and then submitted to metal quantification analysis. Fish exposed to DRWBA and DRWAA treatments showed a significant increase in both the number of erythrocyte micronuclei and the DNA damage index in relation to the control fish; however, they did not present any differences between the two treatments. The results demonstrate that the DRWBA treatment was already genotoxic for the fish, mainly due to dissolved Cu concentrations in the water. The DRWAA treatment probably presented genotoxicity due to the increase in the dissolved fraction and synergistic effects of several metals found in the tailings of the Mariana accident.

Spatial and temporal variations in fish assemblage: testing the zonation concept in small reservoirs.

Large reservoirs usually present spatial gradients in fish assemblage, distinguishing three strata (littoral, pelagic, and bathypelagic) along the vertical and horizontal axes, and three zones (fluvial, transitional, and lacustrine) along the longitudinal axis. The main objective of this study was to assess if small reservoirs also present the spatial gradients in fish assemblage attributes and structure as already observed in large reservoirs. Fish surveys were conducted quarterly, from 2003 to 2008, in the Mourão Reservoir (Mourão River, Paraná, Brazil), using gillnets with different mesh sizes, arranged in all strata of all three zones. Community attributes (species richness and evenness) were calculated for each sample, and differences were tested using three-way ANOVA (factors: zone, strata, year). Community composition was summarized using Correspondence Analysis (CA) and differences were tested with three-way ANOVA for each axis, controlling the same three factors. Because of the high variability in reservoir water level through time, all analyses were made considering temporal variations. Species richness presented a decreasing trend from fluvial to lacustrine zones, and higher values in littoral strata, possibly because upper reaches and littoral regions provide better conditions for fish to feed and to reproduce. Evenness was considerably low, presenting high variability, and no evident pattern. The expected longitudinal gradient was not found in this study indicating longitudinal similarity, contrary to observed in large reservoirs. Vertical and horizontal gradients were observed in all sampling stations, indicating that abiotic and biotic conditions are influencing fish distributions within the reservoir.

Impact of modified diamond-like carbon coatings on the spatial organization and disinfection of mixed-biofilms composed of Escherichia coli and Pantoea agglomerans industrial isolates.

This work investigated the effects of diamond-like carbon (DLC) coatings on the architecture and biocide reactivity of dual-species biofilms mimicking food processing contaminants. Biofilms were grown using industrial isolates of Escherichia coli and Pantoea agglomerans on bare stainless steel (SST) and on two DLC surface coatings (a-C:H:Si:O designated by SICON® and a-C:H:Si designated by SICAN) in order to evaluate their antifouling activities. Quantification and spatial organization in single- and dual-species biofilms were examined by confocal laser scanning microscopy (CLSM) using a strain specific labelling procedure. Those assays revealed that the E. coli isolate exhibited a higher adhesion to the modified surfaces and a decreased susceptibility to disinfectant in presence of P. agglomerans than alone in axenic culture. While SICON® reduced the short-term growth of E. coli in axenic conditions, both DLC surfaces increased the E. coli colonization in presence of P. agglomerans. However, both modified surfaces triggered a significantly higher log reduction of E. coli cells within mixed-species biofilms, thus the use of SICON® and SICAN surfaces may be a good approach to facilitate the disinfection process in critical areas of food processing plants. This study presents a new illustration of the importance of interspecies interactions in surface-associated community functions, and of the need to evaluate the effectiveness of hygienic strategies with relevant multi-species consortia.

Transportation of juvenile tambaqui (Colossoma macropomum) in a closed system.

The objective of this study was to investigate the effect of density, duration and the use of additives to the water during the transportation of juvenile tambaqui (Colossoma macropomum) and use of this data to establish a safe transportation protocol for the species. The tested products and dosages were: salt (1000, 2000 and 3000 mg/L), gypsum (100, 300 and 500 mg/L) and benzocaine (10, 20 and 30 mg/L). Fish were transported in closed systems (plastic bag) at different densities and time periods of up to 24 h. Fish survival (FS) and water quality parameters were monitored immediately after transportation. The remaining fish were kept in floating cages in order to evaluate mortality which occurred up to 96 h after transportation (S96). The best fish density, additives dosages and time period of the transportation was estimated with a general linear model. The effect of the condition factor on FS and S96 was also evaluated. As expected, FS and S96 were significantly related to time and density. FS but not S96, were also were significantly related to treatment. FS with gypsum treatment was not different from controls and FS with table salt and benzocaine treatments were significantly reduced. The condition factor was not related to either FS or S96. FS was inversely correlated with carbon dioxide concentration. It was concluded that the additives did not improve fish transportation survival. Linear models were developed to predict the best transportation densities as a function of time.

Salinity does not alter the effectiveness of menthol as an anesthetic and sedative during the handling and transport of juvenile fat snook (Centropomus parallelus).

The effectiveness of menthol as anesthetic and sedative for fat snook (Centropomus parallelus) was tested at different salinities. In the first experiment, the fish were exposed to different concentrations of menthol (25, 37 and 50 mg L-1) in water at different salinities (0, 17 and 36 ppt). In the second experiment, the fish were transported for 10 hours in water with menthol at concentrations of 0, 3.7 and 7.4 mg L-1 under different salinities. Na+ and K+ ions from fish body and water were analyzed after transport. The optimal concentrations of menthol for a short handling period and surgical induction was 37 and 50 mg L-1, respectively, and these values were independent of salinity. After transport, neither mortality nor significant changes in ammonia or dissolved oxygen were observed between treatments at the different salinities. The nitrite levels were lower in freshwater than in brackish and saltwater, but did not change with mentol. The total body levels of Na+ increased with the salinity increase. Menthol is an effective anesthetic for handling of juvenile fat snook at different salinities. Menthol did not influence the measured water parameters and body ions, and it is not necessary for the transport of fat snook.

Do river basins influence the composition of functional traits of fish assemblages in Neotropical reservoirs? / As bacias hidrográficas influenciam a composição funcional da assembleia de peixes em reservatórios da região Neotropical?

Abstract In aquatic environments, dams are considered one of the main threats to fish species, acting as an environmental filter for certain functional traits. Although there is some predictability in the composition of the functional traits in reservoirs, it is hypothesized that the environmental filters imposed by evolutionary processes, linked to the characteristics of the basins, are determinant for the functional composition of the traits in reservoirs. For this we performed a PCoA using the functional traits composition matrix of the reservoirs. We used PERMANOVA to test the difference in functional composition between basins. We performed the same process for the species composition matrix to compare the patterns. In this study, there were taxonomic and functional differences among reservoirs inserted in different basins. It was observed that the basin is a determining factor for the functional structure of fish assemblage in reservoirs. When compared, functional and taxonomic structures follow the same pattern, although functionally the reservoir tends to be more similar. These results reinforce the idea that reservoirs act as filters for functional traits (e.g., related with reproduction, feeding and habitat use), although there is a great influence of evolutionary processes related to the basin's characteristics and origin of the ichthyofaunistic province.

Resumo Em ambientes aquáticos, a construção de barragens é considerada uma das principais ameaças para as espécies de peixes, atuando como filtro ambiental para determinados traços funcionais. Assim, embora exista certa previsibilidade na composição dos traços funcionais em reservatórios, é hipotetizado que os filtros ambientais impostos pelos processos evolutivos, ligados as características das bacias, são determinantes para a composição funcional dos traços nos reservatórios. Para isso realizamos uma PCoA utilizando a matriz de composição de traços funcionais dos reservatórios. Utilizamos a PERMANOVA para testar a diferença da composição funcional entre as bacias. Realizamos o mesmo processo para a matriz de composição de espécies para comparar os padrões. Foi possível observar que a bacia hidrográfica é um fator determinante para a estruturação funcional da assembleia de peixe em reservatórios. Quando comparadas, a estrutura funcional e taxonômica, ambas seguem o mesmo padrão, embora funcionalmente os ambientes tendem a ser mais semelhantes. Esses resultados reforçam a ideia de que reservatórios atuam como filtros para determinados traços funcionais (e.g., relacionados à reprodução, alimentação e uso de habitat), embora exista uma grande influência dos processos evolutivos ligados a característica da bacia e da origem da província ictiofaunística.

Metabolic adjustments in two Amazonian cichlids exposed to hypoxia and anoxia.

The effects of graded hypoxia on the physiological and biochemical responses were examined in two closely related species of cichlids of the Amazon: Astronotus crassipinnis and Symphysodon aequifasciatus. Ten fish of each species were exposed to graded hypoxia for 8 h in seven oxygen concentrations (5.92, 3.15, 1.54, 0.79, 0.60, 0.34, and 0.06 mg O(2) L(-)(1)), with the aim to evaluate hypoxia tolerance and metabolic adjustments, where plasma glucose and lactate levels, hepatic and muscle glycogen contents, and maximum enzyme activities (PK, LDH, MDH and CS) in skeletal and cardiac muscles were measured. Another experimental set was done to quantify oxygen consumption (MO(2)) and opercular movements in two oxygen concentrations. Hypoxia tolerance differed between the two species. Astronotus crassipinnis was able to tolerate anoxia for 178 min while S. aequifasciatus was able to withstand 222 min exposure in deep hypoxia (0.75 mg O(2) L(-)(1)). Suppressed MO(2) was observed during exposure to 0.34 (A. crassipinnis) and 0.79 mg O(2) L(-)(1) (S. aequifasciatus), while opercular movements increased in both species exposed to hypoxia. Higher levels of muscle and liver glycogen and larger hypoxia-induced increases in plasma glucose and lactate were observed in A. crassipinnis, which showed a higher degree of hypoxia tolerance. Changes in enzyme levels were tissue-specific and differed between species suggesting differential abilities in down-regulating oxidative pathways and increasing anaerobic metabolism. Based on the present data, we conclude that these animals are good anaerobes and highly adapted to their environment, which is allowed by their abilities to regulate metabolic pathways and adjust their enzyme levels.

Escherichia coli adhesion, biofilm development and antibiotic susceptibility on biomedical materials.

The aim of this work was to test materials typically used in the construction of medical devices regarding their influence in the initial adhesion, biofilm development and antibiotic susceptibility of Escherichia coli biofilms. Adhesion and biofilm development was monitored in 12-well microtiter plates containing coupons of different biomedical materials--silicone (SIL), stainless steel (SS) and polyvinyl chloride (PVC)--and glass (GLA) as control. The susceptibility of biofilms to ciprofloxacin and ampicillin was assessed, and the antibiotic effect in cell morphology was observed by scanning electron microscopy. The surface hydrophobicity of the bacterial strain and materials was also evaluated from contact angle measurements. Surface hydrophobicity was related with initial E. coli adhesion and subsequent biofilm development. Hydrophobic materials, such as SIL, SS, and PVC, showed higher bacterial colonization than the hydrophilic GLA. Silicone was the surface with the greatest number of adhered cells and the biofilms formed on this material were also less susceptible to both antibiotics. It was found that different antibiotics induced different levels of elongation on E. coli sessile cells. Results revealed that, by affecting the initial adhesion, the surface properties of a given material can modulate biofilm buildup and interfere with the outcome of antimicrobial therapy. These findings raise the possibility of fine-tuning surface properties as a strategy to reach higher therapeutic efficacy.

First record of Neobenedenia melleni (Monogenea: Capsalidae) in dog snapper (Lutjanus jocu) in the western South Atlantic / Primeiro registro de Neobenedenia melleni (Monogenea: Capsalidae) em dentão (Lutjanus jocu) no oeste do Atlântico Sul

Neobenedenia melleni (MacCallum, 1927) (Monogenea) é um patógeno amplamente distribuído em cultivo de teleósteos marinhos no mundo. Com o crescimento da piscicultura marinha no Brasil, faz-se necessário um maior cuidado em relação à identificação e ao tratamento das principais patologias nesse tipo de cultivo. Este estudo relata a primeira ocorrência de Neobenedenia melleni em dentão (Lutjanus jocu) no oeste do Atlântico Sul. Também são sugeridos procedimentos adotados para eliminação desse parasito em peixes cultivados em laboratório.(AU)

Effect of copper on the secretion of human growth hormone.

The response of human growth hormone to the oral administration of 5.0 mg copper was studied in plasma from 12 normal adults. Blood samples were collected at 30 min intervals over a period of 240 min after two basal measurements taken at time = -30 and time = 0 min. Six subjects responded to the stimulus with increased growth hormone secretion, revealing a positive correlation with plasma copper levels. The other six subjects presented a similar rise in plasma copper levels but no increase in plasma growth hormone levels. These results suggest that acute, high blood copper levels can increase basal growth hormone secretion in normal individuals, presumably by acting on the hypothalamic center.

[Illness, hospitalization and anxiety: an approach to mental health]. / Doenças, hospitalização e ansiedade: uma abordagem em saúde mental.

With the purpose of completely approaching the patient in the hospital, this research had the goal to identify the generating factors of the of anxiety patient and how they express their uneasiness towards the illness and the hospitalization the data were collected from april/may/96 with adults in a school-hospital and was based on a guide for observation of the anxieting situations and in an interview guide. We found out that the patients' major concerns were: Knowing if their illness has aure, how long they will be there, their and the support of the family. They get sadder at night and in the afternoon, when the staff is reduced, there is more silence and they feel lonely. Only a small percentage of them have the consistent information about the disease and treatment, however, the hospital is mainly identified as a good place for the possibility of cure, good assistance and food. Witnessing the suffering and the dying risk of the neighbour, be discharged, exams and treatment procedures suspended on cancelled, bling communicated of the necessity of bling operated on that the disease doesn't have a cure, were the anxieting factors that were remanked not only in the immediate sections, but also in the late ones of the anxieting situations, prevail passive attitudes such as sadness, crying, depression and negativism. We concluded that the psychic and emotional conditions of the patients in the hospital have to be taken on consideration on hospitals emphasizing a comsiete approach, with special care of the speed of the actions and the consistence of the information given to the patient about their health and treatment.

Regional 3D superimposition to assess temporomandibular joint condylar morphology.

OBJECTIVES: To investigate the reliability of regional three-dimensional registration and superimposition methods for assessment of temporomandibular joint condylar morphology across subjects and longitudinally. METHODS: The sample consisted of cone beam CT scans of 36 patients. The across-subject comparisons included 12 controls, mean age 41.3 ± 12.0 years, and 12 patients with temporomandibular joint osteoarthritis, mean age 41.3 ± 14.7 years. The individual longitudinal assessments included 12 patients with temporomandibular joint osteoarthritis, mean age 37.8 ± 16.7 years, followed up at pre-operative jaw surgery, immediately after and one-year post-operative. Surface models of all condyles were constructed from the cone beam CT scans. Two previously calibrated observers independently performed all registration methods. A landmark-based approach was used for the registration of across-subject condylar models, and temporomandibular joint osteoarthritis vs control group differences were computed with shape analysis. A voxel-based approach was used for registration of longitudinal scans calculated x, y, z degrees of freedom for translation and rotation. Two-way random intraclass correlation coefficients tested the interobserver reliability. RESULTS: Statistically significant differences between the control group and the osteoarthritis group were consistently located on the lateral and medial poles for both observers. The interobserver differences were ≤0.2 mm. For individual longitudinal comparisons, the mean interobserver differences were ≤0.6 mm in translation errors and 1.2° in rotation errors, with excellent reliability (intraclass correlation coefficient >0.75). CONCLUSIONS: Condylar registration for across-subjects and longitudinal assessments is reliable and can be used to quantify subtle bony differences in the three-dimensional condylar morphology.

Genotoxicity effects on Geophagus brasiliensis fish exposed to Doce River water after the environmental disaster in the city of Mariana, MG, Brazil / Efeitos da genotoxicidade em peixes da espécie Geophagus brasiliensis expostos a água do Rio Doce após o desastre ambiental na cidade de Marina, MG, Brasil

Abstract The Doce River basin has suffered the largest environmental accident ever occurred in Brazil with the influx of tailings from Fundão and Santarém, belonging to Samarco mining company, due to the disaster in Mariana. A spill between 50 and 60 million m3 of tailings was estimated by the company. According to Samarco, the wastewater was composed mainly of clay, silt and heavy metals like iron, copper and manganese. Thereby, the objective of the present study was evaluated the genotoxic damage in juvenile of Geophagus brasiliensis (Quoy e Gaimard, 1824) exposed to Doce river water before (DRWBA - Doce River water before acident) and after (DRWAA - Doce River water after acident) the influx of tailings from the Germano and Santarém Dam disasters in Mariana, MG, Brazil. For this, 24 individuals of the species G. brasiliensis (obtained on IFES/ALEGRE fish culture) were submitted to a bioassay with three treatments and eight replicates. The treatments were: 1) Control water (water from the urban water supply system, filtered with a 0.45 µm membrane), 2) DRBA and 3) DRAA. After 96 h, these fishes were anesthetized to remove blood for evaluation of genotoxic damage (micronucleus and comet). For the bioassay, a total of 80 L of The Doce River water were collected before the influx of tailings and after the influx and then submitted to metal quantification analysis. Fish exposed to DRWBA and DRWAA treatments showed a significant increase in both the number of erythrocyte micronuclei and the DNA damage index in relation to the control fish; however, they did not present any differences between the two treatments. The results demonstrate that the DRWBA treatment was already genotoxic for the fish, mainly due to dissolved Cu concentrations in the water. The DRWAA treatment probably presented genotoxicity due to the increase in the dissolved fraction and synergistic effects of several metals found in the tailings of the Mariana accident.

Resumo A bacia do Rio Doce sofreu o maior acidente ambiental com o influxo de rejeitos de Fundão e Santarém, pertencentes à empresa de mineração Samarco, devido ao desastre em Mariana. Um derramamento entre 50 e 60 milhões de m3 de rejeitos foi estimado pela empresa. De acordo com a Samarco, o rejeito despejado era composto principalmente de argila, silte e alguns metais pesados como ferro, cobre e manganês. Com isso, o presente estudo teve como objetivo avaliar os danos genotóxicos em juvenis de Geophagus brasilienses expostos a água do rio Doce antes (DRWAA - água do Rio Doce antes do acidente) e depois (DRWBA- água do Rio Doce depois do acidente) da chegada dos rejeitos do rompimento das barragens de Germano e Santarém em Mariana, MG, Brasil. Para isso, 24 indivíduos da espécie G. brasilienses (obtidos na piscicultura do IFES/ALEGRE) foram submetidos a um bioensaio com três tratamentos e oito réplicas. Os tratamentos eram: 1) Controle (com água do abastecimento urbano, filtrada com filtro analítico de 0,45 µm); 2) DRWBA e 3) DRWAA. Após um período de 96 h, esses peixes foram anestesiados para retirada de sangue para avaliação dos danos genotóxicos (micronúcleo e cometa). Para a realização do bioensaio, um total de 80 L de água do Rio Doce foram coletados antes da chegada dos rejeitos e outros 80 L foram coletados depois da chegada dos rejeitos e ambas foram submetidas a análises de quantificação de metal. Os peixes expostos ao DRWBA e ao DRWAA apresentaram um aumento significativo na quantidade de micronúcleos eritrocitários e no índice de danos do DNA em relação aos peixes controle, no entanto não apresentaram diferenças entre si. Os resultados obtidos demonstram que a DRWBA já era genotóxica para os peixes, principalmente, em função das concentrações de Cu dissolvido na água. A DRWAA apresentou genotixicidade, provavelmente, em função do aumento da fração dissolvida e do efeito sinérgico de diversos metais presentes nos rejeitos do acidente de Mariana.

Percentage of Impervious Surface Soil as Indicator of Urbanization Impacts in Neotropical Aquatic Insects.

Several recent studies have shown a strong correlation between the area of impervious surface soil (IS) and the insect community structure from urban streams. This study assessed whether this relationship is observed in Neotropical streams. We examined if an increased IS reduces the diversity and simplifies the trophic structure of the community of Ephemeroptera, Plecoptera, and Trichoptera. An IS threshold was detected between 1.6 and 9.3%, in which there is a change in the community, both in taxonomic richness and trophic structure. Among the 27 genera identified, only 15 occurred in streams with IS > 9%, while 24 genera were registered in streams with IS < 2%. The trophic guilds of predators and shredders were not observed in streams with high IS, decreasing the number of guilds in these streams from 5 to 3, compared with the streams with low IS. Three hypotheses with cumulative effect have been proposed to explain such variations. Based on the IS threshold verified, the creation of a mosaic of land use, where some subbasins would be sacrificed and others would be preserved, was suggested as a mitigation measure for the impacts caused by urbanization in the Neotropical aquatic insects' fauna.