Papers by Daniella da Costa Pereira
Revista brasileira de zoociências, Nov 4, 2016
Ciliates are an essential component of microbial food webs, connecting biomass production to high... more Ciliates are an essential component of microbial food webs, connecting biomass production to higher trophic levels and providing substrates for bacterial growth. Bacteria are widespread in sea sediment and the first to metabolize organic matter. Heavy metals are toxic and bind to particulate organic matter. This work aims to study the influence of heavy metals (Zn and Cu) on D. appendiculata and their naturally associated bacteria, both from Guanabara Bay during 96 h bioassay with 0, 0.001, 0.009, 0.05, 0.1 mg L-1 and maximum concentration stipulated by CONAMA 357 (Zn 5.0; Cu 1.0 mg L-1). It was analyzed for tolerance, resistance and biomass production. In Zn control, ciliate produced 1.24x10 2-2.47x10 3 µg C cm-3 (0-96 h), with 0.009 mg Zn L-1 reaches 2.49x10 2-1.93x10 3 µg C cm-3 (0-96 h). Their naturally associated bacteria, in Zn control, produced 5.0x10-2-5.67x10-2 µg C cm-3 (0-96 h), with 0.1 mg Zn L-1 4.87x10-2-8.38x10-2 µg C cm-3 (0-96 h). In Cu control, D. appendiculata produced 1.04x10 2-3.12x10 2 µg C cm-3 (0-96 h), with 0.009 mg Cu L-1 biomass was 8.31x10 1-7.27x10-2 µg C cm-3 (0-96 h) and with CONAMA concentration was below detection level. Their naturally associated bacteria, in Cu control, produced 1.20x10-2-5.14x10-2 µg C cm-3 (0-96 h) and with 0.1 mg Cu L-1 7.40x10-4-3.81x10-2 µg C cm-3 (0-96 h), with CONAMA concentration 5.14x10-2 µg C cm-3 (96 h). D. appendiculata are tolerant to 0.09 mg L-1 and resistant to 0.1 mg L-1 after 24 h to Zn-Cu and LD50 stipulated was 1.17 (Zn) 0.90 (Cu) mg L-1. Microbial loop was functional in low concentration of Zn and Cu, but their diversity in nature was affected.
Latin American Journal of Aquatic Research, May 10, 2014
The influence of copper on the ciliate Euplotes sp. and associated bacteria isolated from sedimen... more The influence of copper on the ciliate Euplotes sp. and associated bacteria isolated from sediment samples of Guanabara Bay were investigated in bioassays. This region is highly affected by heavy metals such as copper, from solid waste constantly dumped in the bay and other sources such as industrial effluents, antifouling paints, atmospheric deposition and urban drainage, and even today there are few data on the metal toxicity to the ecosystem of the Bay of Guanabara. Bioassays were conducted to estimate the LC 50-24 h of copper, in order to determine the concentration of metal bearing 50% of the population mortality. The results indicated that the concentrations of 0.05 and 0.009 mg L-1 presented no toxicity to Euplotes sp. The associated bacteria are tolerant to copper concentrations used in bioassays, and suggest that they could be used as a potential agent in the bioremediation of areas affected by copper.
ABSTRACT. The influence of copper on the ciliate Euplotes sp. and associated bacteria isolated fr... more ABSTRACT. The influence of copper on the ciliate Euplotes sp. and associated bacteria isolated from sediment samples of Guanabara Bay were investigated in bioassays. This region is highly affected by heavy metals such as copper, from solid waste constantly dumped in the bay and other sources such as industrial effluents, antifouling paints, atmospheric deposition and urban drainage, and even today there are few data on the metal toxicity to the ecosystem of the Bay of Guanabara. Bioassays were conducted to estimate the LC50– 24 h of copper, in order to determine the concentration of metal bearing 50 % of the population mortality. The results indicated that the concentrations of 0.05 and 0.009 mg L-1 presented no toxicity to Euplotes sp. The associated bacteria are tolerant to copper concentrations used in bioassays, and suggest that they could be used as a potential agent in the bioremediation of areas affected by copper.
Ciliates are an essential component of microbial food webs, connecting biomass production to high... more Ciliates are an essential component of microbial food webs, connecting biomass production to higher trophic levels and providing substrates for bacterial growth. Bacteria are widespread in sea sediment and the first to metabolize organic matter. Heavy metals are toxic and bind to particulate organic matter. This work aims to study the influence of heavy metals (Zn and Cu) on D. appendiculataand their naturally associated bacteria, both from Guanabara Bay during 96 h bioassay with 0, 0.001, 0.009, 0.05, 0.1 mg L-1 and maximum concentration stipulated by CONAMA 357 (Zn 5.0; Cu 1.0 mg L -1). It was analyzed for tolerance, resistance and biomass production. In Zn control, ciliate produced 1.24x10 2-2.47x10 3µg C cm -3 (0-96 h), with 0.009 mg Zn L-1 reaches 2.49x10 2 -1.93x10 3µg C cm -3 (0-96 h). Their naturally associated bacteria, in Zn control, produced 5.0x10 -2 -5.67x10 -2µg C cm -3 (0-96 h), with 0.1 mg Zn L-1 4.87x10 -2 -8.38x10-2µg C cm -3 (0-96 h). In Cu control, D. appendicula...
Biofilm, 2020
Microorganisms, such as bacteria, tend to aggregate and grow on surfaces, secreting extracellular... more Microorganisms, such as bacteria, tend to aggregate and grow on surfaces, secreting extracellular polymeric substances (EPS), forming biofilms. Biofilm formation is a life strategy, because through it microorganisms can create their own microhabitats. Whether for remediation of pollutants or application in the biomedical field, several methodological approaches are necessary for a more accurate analysis of the role and potential use of bacterial biofilms. The use of computerized microtomography to monitor biofilm growth appears to be an advantageous tool due to its non-destructive character and its ability to render 2D and 3D visualization of the samples. In this study, we used several techniques such as analysis of microbiological parameters and biopolymer concentrations to corroborate porosity quantified by 2D and 3D imaging. Quantification of the porosity of samples by microtomography was verified by increased enzymatic activity and, consequently, higher EPS biopolymer synthesis to form biofilm, indicating growth of the biofilm over 96 h. Our interdisciplinary approach provides a better understanding of biofilm growth, enabling integrated use of these techniques as an important tool in bioremediation studies of environments impacted by pollutants.
Regional Studies in Marine Science, 2016
Abstract The main focus of this study was to evaluate the copper sensitivity of Euplotes vannus ,... more Abstract The main focus of this study was to evaluate the copper sensitivity of Euplotes vannus , Euplotes crassus , and their naturally associated bacteria from Guanabara Bay, a Brazilian polluted bay, during 96 h of laboratory assay. In the control, both microorganisms did not appear to be negatively affected, and E . vannus and E . crassus produced the highest biomass at 48 h (6.3×10 2 and 1.14 × 10 3 μ g C cm − 3 ). With 0.001 mg Cu L −1 , E . vannus and E . crassus showed the highest biomass (1.90×10 −1 μg C cm −3 , 24–72 h, and 8.52×10 2 μg C cm −3 , 24 h), while their bacteria showed highest biomass at 24 h with exposition of 0,1 mg Cu L −1 (1.32 μg C cm −3 , E . vannus ) and with 0.001 mg Cu L −1 (1.90×10 −1 μg C cm −3 , E . crassus ). However, E . crassus showed more resistance and both following bacteria showed better adaptation to higher copper concentration, possibly due to previous environmental selection. The basis of the microbial loop may be active under copper stress and facilitates the biomagnification process. Capsule The Euplotes resistance was evaluated with their naturally associated bacteria to copper. The association of Euplotes and bacteria positively influenced bacterial survival during copper stress.
Seminario Sobre Ecotoxicologia Aquatica, Oct 22, 2013
Latin American Journal of Aquatic Research, May 1, 2014
Seminario Sobre Ecotoxicologia Aquatica, Oct 18, 2013
Latin American Journal of Aquatic Research, 2014
The influence of copper on the ciliate Euplotes sp. and associated bacteria isolated from sedimen... more The influence of copper on the ciliate Euplotes sp. and associated bacteria isolated from sediment samples of Guanabara Bay were investigated in bioassays. This region is highly affected by heavy metals such as copper, from solid waste constantly dumped in the bay and other sources such as industrial effluents, antifouling paints, atmospheric deposition and urban drainage, and even today there are few data on the metal toxicity to the ecosystem of the Bay of Guanabara. Bioassays were conducted to estimate the LC 50-24 h of copper, in order to determine the concentration of metal bearing 50% of the population mortality. The results indicated that the concentrations of 0.05 and 0.009 mg L-1 presented no toxicity to Euplotes sp. The associated bacteria are tolerant to copper concentrations used in bioassays, and suggest that they could be used as a potential agent in the bioremediation of areas affected by copper.
Brazilian Journal of Oceanography, 2008
Thirty sediment samples were collected in Guanabara Bay in August, November and December 2005. Th... more Thirty sediment samples were collected in Guanabara Bay in August, November and December 2005. The material was analyzed for organic matter, total and faecal coliforms, heterotrophic bacteria, bacterial respiratory activity, esterase activity and electron transport system activity. The organic matter in the superficial sediments (2 cm) ranged from 4 to 6%. The highest level of total coliforms and faecal coliforms were 1.7 x 10(5) MPN/g and 1.1 x 10³ MPN/g, respectively. Heterotrophic bacteria presented the highest values at station 7 (4.1 x 10(6) CFU/g) and the lowest values at station 3 (7 x 10(4) CFU/g) (northwestern part of Guanabara Bay). Esterase enzyme activity showed activity in the sediment of all 30 stations. Electron transport system activity ranged between 0.047 muL O2/h/g and 0.366 muL O2/h/g at six stations. The benthic microbial foodweb is anaerobic. Anaerobic processes such as fermentation, denitrification and sulphate-reduction are responsible for the biogeochemical ...
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Papers by Daniella da Costa Pereira