Draft genome of Nocardia farcinica TRH1, a linear and polycyclic aromatic hydrocarbon-degrading bacterium isolated from the coast of Trindade Island, Brazil

Here, we report the draft genome sequence and annotation of Nocardia farcinica TRH1, a petroleum hydrocarbons degrading Actinobacteria isolated from the coastal water of Trindade Island, Brazil.(AU)

Bioremediation of polycyclic aromatic hydrocarbon (PAH) compounds: (acenaphthene and fluorene) in water using indigenous bacterial species isolated from the Diep and Plankenburg rivers, Western Cape, South Africa

This study was conducted to investigate the occurrence of PAH degrading microorganisms in two river systems in the Western Cape, South Africa and their ability to degrade two PAH compounds: acenaphthene and fluorene. A total of 19 bacterial isolates were obtained from the Diep and Plankenburg rivers among which four were identified as acenaphthene and fluorene degrading isolates. In simulated batch scale experiments, the optimum temperature for efficient degradation of both compounds was determined in a shaking incubator after 14 days, testing at 25 °C, 30 °C, 35 °C, 37 °C, 38 °C, 40 °C and 45 °C followed by experiments in a Stirred Tank Bioreactor using optimum temperature profiles from the batch experiment results. All experiments were run without the addition of supplements, bulking agents, biosurfactants or any other form of biostimulants. Results showed that Raoultella ornithinolytica, Serratia marcescens, Bacillus megaterium and Aeromonas hydrophila efficiently degraded both compounds at 37 °C, 37 °C, 30 °C and 35 °C respectively. The degradation of fluorene was more efficient and rapid compared to that of acenaphthene and degradation at Stirred Tank Bioreactor scale was more efficient for all treatments. Raoultella ornithinolytica, Serratia marcescens, Bacillus megaterium and Aeromonas hydrophila degraded a mean total of 98.60%, 95.70%, 90.20% and 99.90% acenaphthene, respectively and 99.90%, 97.90%, 98.40% and 99.50% fluorene, respectively. The PAH degrading microorganisms isolated during this study significantly reduced the concentrations of acenaphthene and fluorene and may be used on a larger, commercial scale to bioremediate PAH contaminated river systems.(AU)

Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas

The goal of this investigation was to isolate competent polynuclear aromatic hydrocarbons degraders that can utilize polynuclear aromatic hydrocarbons of former industrial sites at McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment method based on soil slurry, we isolated, screened and purified two bacterial species strains PB1 and PB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains were assigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonas sp. PB2). Both isolates showed promising metabolic capacity on pyrene sprayed MS agar plates during the preliminary investigations. Using time course studies in the liquid cultures at calculated concentrations 123, 64, 97 and 94 ppm for naphthalene, chrysene, fluroanthene and pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilization of the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and 40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developed a model R2 = 1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, we confirm that the former industrial site soil microbial communities may be explored for the biorestoration of the industrial site.(AU)

Bioremediation of polyaromatic hydrocarbons (PAHs) using rhizosphere technology

The remediation of polluted sites has become a priority for society because of increase in quality of life standards and the awareness of environmental issues. Over the past few decades there has been avid interest in developing in situ strategies for remediation of environmental contaminants, because of the high economic cost of physicochemical strategies, the biological tools for remediation of these persistent pollutants is the better option. Major foci have been considered on persistent organic chemicals i.e. polyaromatic hydrocarbons (PAHs) due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity. Rhizoremediation, a specific type of phytoremediation that involves both plants and their associated rhizospheric microbes is the creative biotechnological approach that has been explored in this review. Moreover, in this review we showed the significance of rhizoremediation of PAHs from other bioremediation strategies i.e. natural attenuation, bioaugmentation and phytoremediation and also analyze certain environmental factor that may influence the rhizoremediation technique. Numerous bacterial species were reported to degrade variety of PAHs and most of them are isolated from contaminated soil, however few reports are available from non contaminated soil. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Finally, exploring the molecular communication between plants and microbes, and exploiting this communication to achieve better results in the elimination of contaminants, is a fascinating area of research for future perspective.(AU)

Respostas bioquímicas em três espécies de ostras do gênero Crassostrea (SACCO, 1897) expostas a criseno

A maricultura pode ser diretamente afetada pela contaminação do ambiente aquático, pois utiliza desses recursos para desenvolver a atividade. Ostras do gênero Crassostrea, incluindo aqui a ostra do Pacífico C. gigas, e as ostras do mangue C. gasar e C. rhizophorae, apresentam potencial zootécnico e relevância econômica para a maricultura brasileira. O criseno (CHR) é considerado um HPA prioritário para o monitoramento de poluentes orgânicos, pois apresenta significativo potencial carcinogênico, mutagênico, genotóxico e de desregulação endócrina em sistemas biológicos. Nesse sentido, objetivo do presente estudo foi analisar comparativamente a atividade das enzimas envolvidas na biotransformação de xenobióticos e no sistema de defesa antioxidante: Superóxido dismutase (SOD), Catalase (CAT), Glutationa Peroxidase (GPx), Glutationa S-Transferase (GST), Glutationa Redutase (GR) e Glicose 6-fosfato desidrogenase (G6PDH) em brânquias e glândulas digestivas (n=10) nas três espécies de ostras do gênero Crassostrea expostas a CHR (10µg/L) por 96 h. Ostras expostas foram comparadas aos respectivos grupos controle (água do mar, salinidade 30, solvente DMSO 0,002%). As três espécies de ostras avaliadas demonstraram consumo de CHR na água dos aquários e bioconcentração nos tecidos moles. Em relação às respostas bioquímicas, em brânquias de ostras C. gigas foi observado significativo decréscimo na atividade GR e em glândulas digestivas foi observada diminuição da atividade SOD e aumento na atividade CAT. Em C. gasar houve significativo decréscimo na atividade SOD e GR e aumento na atividade CAT nas brânquias. Não foram observadas alterações nas atividades enzimáticas em glândulas digestivas das ostras C. gasar expostas à CHR. Nas brânquias de ostras C. rhizophorae expostas ao CHR foi observado aumento na atividade SOD e decréscimo na atividade G6PDH. Em uma visão global das respostas bioquímicas, as espécies C. gigas e C. gasar foram mais responsivas ao CHR, em relação à espécie nativa C. rhizophorae, sugerindo que as primeiras apresentaram maior sensibilidade à exposição ao CHR. As ostras C. rhizophorae apresentaram menor número de alterações nas respostas bioquímicas resultantes à exposição, o que sugere uma maior capacidade antioxidante da espécie e adaptação às situações pró-oxidantes, em relação à C. gigas e C. gasar. Comparativamente, as distintas respostas na biotransformação e defesa antioxidante observadas pelas espécies expostas ao CHR podem estar relacionadas com a plasticidade fenotípica associada aos respectivos nichos ecológicos que ocupam e a adaptação às respectivas condições ambientais.

Mariculture can be directly affected by contamination of the aquatic environment, as it uses these resources to develop the activity. Oysters of the genus Crassostrea, including the Pacific oyster C. gigas, and the mangrove oysters C. gasar and C. rhizophorae, present zootechnical potential and economic relevance for Brazilian mariculture. Chrysene (CHR) is considered a priority HPA for monitoring organic pollutants, since it has a significant carcinogenic, mutagenic, genotoxic and endocrine disrupting potential in biological systems. Studies report changes in the xenobiotic biotransformation and the antioxidant defense system and oxidative damage to macromolecules in fish and molluscs exposed to CHR. Therefore, the aim of the present study was to analyze comparatively the activity of the enzymes involved in the xenobiotic biotransformation and the antioxidant defense system: Superoxide dismutase (SOD), Catalase (CAT), Glutathione Peroxidase (GPx), Glutathione S-Transferase GST), Glutathione Reductase (GR) and Glucose 6-phosphate dehydrogenase (G6PDH) in gills and digestive glands (n = 10) in the three species of Crassostrea oysters exposed for 96 h to CHR (10 g/L). Exposed oysters were compared to the respective control groups (seawater, salinity 30, solvent DMSO 0.002%). The three species of oysters evaluated showed consumption of CHR in aquaria water and bioconcentration in soft tissues. Regarding the biochemical responses, a significant decrease in GR activity and in digestive glands was observed in C. gigas oyster gills. There was a decrease in SOD activity and an increase in CAT activity. In C. gasar there was a significant decrease in SOD and GR activity and an increase in CAT activity in the gills. No alterations were observed in the enzymatic activities in the digestive glands of C. gasar oysters exposed to CHR. In the gills of C. rhizophorae oysters exposed to CHR an increase in SOD activity and a decrease in G6PDH activity was observed. In overview of the biochemical responses, C. gigas and C. gasar species were more responsive to CHR than native species C. rhizophorae, suggesting that they are more sensitive to exposure to CHR. Oysters C. rhizophorae showed few biochemical responses after CHR exposure, suggesting higher antioxidant capacity and defense against reactive oxygen species production than C. gigas and C. gasar. Comparatively, the different responses in the biotransformation and antioxidant defense observed by the species may be related to the phenotypic plasticity associated to their respective ecological niches and the adaptation to environmental conditions.

RESPOSTAS METABÓLICAS E MOLECULARES DE Chironomus sancticaroli STRIXINO & STRIXINO, 1981 (DIPTERA: CHIRONOMIDAE) EXPOSTA AO MALATHION, FENANTRENO E CÁDMIO

A complexidade das inúmeras combinações de xenobióticos nos ambientes aquáticos representa um grande desafio para a avaliação do risco ecológico. A espécie bioindicadora Chironomus sancticaroli foi utilizada como modelo de exposição para se compreender os efeitos individuais e das misturas combinadas do metal cádmio, do inseticida organofosforado malathion e do hidrocarboneto policíclico aromático fenantreno, poluentes que representam diferentes classes de xenobióticos amplamente encontrados em lugares impactados no mundo. As larvas de IV ínstar foram expostas por 48h a três concentrações nominais de cádmio (0,001, 3,2 e 7,4 mg L-1), malathion (0,0001, 0,0564 e 0,1006 mg L-1) e fenantreno (0,0025, 1,25 e 2,44 mg L-1), além dos controles água e solvente (etanol p.a.). As menores concentrações de cada poluente representam o máximo permitido pela legislação brasileira para rios de Classe 1 e 2 e as outras duas concentrações representam, as concentrações letais CL25 e CL50 previamente calculadas de cada composto para a espécie. Foram quantificadas as concentrações biodisponíveis dos poluentes em todos os experimentos para se confirmar as concentrações nominais. Foi utilizada a abordagem de unidades tóxicas para se prever a toxicidade das misturas. Os biomarcadores utilizados foram as atividades das enzimas acetilcolinesterase (AChE), esterase alfa (EST alfa), esterase beta (EST beta), glutationa S-transferase (GST), catalase (CAT), superóxido dismutase (SOD), os danos de peroxidação lipídica (LPO), o conteúdo total de hemoglobinas (Hb) e a expressão gênica de quatro hemoglobinas: HbB, HbC, HbD e HbE. Nas larvas de Chironomus sancticaroli, os biomarcadores bioquímicos foram mais sensíveis aos efeitos provocados pelo malathion, em seguida o cádmio e fenantreno. As misturas binárias e terciárias provocaram mais efeitos que as exposições individuais para todos os poluentes. Dentre as misturas, a exposição binária cádmio + malathion e a exposição terciária cádmio + malathion + fenantreno foram as mais tóxicas para a espécie. Com base nos resultados os três poluentes podem ser considerados neurotóxicos, capazes de gerar alterações metabólicas e estresse oxidativo, gerando os danos de peroxidação lipídica e as alterações no conteúdo e expressão gênica de hemoglobinas em Chironomus sancticaroli. As interações observadas entre os xenobióticos investigados poderão auxiliar no direcionamento de futuros estudos diretamente ligados à avaliação de risco ecológico e conservação da biota dos ecossistemas aquáticos.

The complexity of numerous combinations of xenobiotics in aquatic environments represents a major challenge for ecological risk assessment. In this thesis, the bioindicator species Chironomus sancticaroli was used as a model organism to assess the individual and combined effects of the metal cadmium, the organophosphate insecticide malathion and polycyclic aromatic hydrocarbon phenanthrene, pollutants that represent different classes of xenobiotics widely detected in impacted areas worldwide. IV instar larvae were exposed for 48 hours at three nominals concentrations of cadmium (0.001, 3.2 and 7.4 mg L-1), malathion (0.0001, 0.0564 and 0.1006 mg L-1), and phenanthrene (0.0025, 1.25 and 2.44 mg L-1), water and solvent (ethanol p.a.) controls. The lowest concentrations of each pollutant represent the maximum limit allowed by Brazilian law to Class 1 and 2 rivers, while the other two concentrations represent the lethal concentrations LC25 and LC50 previously calculated for each compound for the species. The bioavailable concentrations of the pollutants were quantified in all experiments to confirm nominal concentrations. The toxic unit (TU) approach was used to predict mixture toxicity. Measured biomarkers were the enzymatic activities of acetylcholinesterase (AChE), esterase alpha (EST alpha), esterase beta (EST beta), glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), the lipid peroxidation damage (LPO), the total content of hemoglobin (Hb) and gene expression of four hemoglobins: HbB, HbC, HbD and HbE. Biochemical biomarkers of the larvae of Chironomus sancticaroli were most sensitive to measure effects caused by malathion, followed by cadmium and phenanthrene. Compared to individual exposures, both binary and tertiary mixtures caused synergistic responses. Among the mixtures, the binary exposure cadmium + malathion and the tertiary exposure cadmium + malathion + phenanthrene were the most toxic to Chironomus sancticaroli. Based on these results, all three pollutants can be considered neurotoxic, capable of generating a high degree of metabolic and oxidative stress, potentially causing lipid peroxidation damage and changes in hemoglobin content and as well as gene expression. The observed interactions between the investigated xenobiotics may assist in future studies supporting ecological risk evaluation and conservation of the aquatic ecosystem.

Degradation of Benzo [a] Pyrene by a novel strain Bacillus subtilis BMT4i (MTCC 9447)

Benzo [a] Pyrene (BaP) is a highly recalcitrant, polycyclic aromatic hydrocarbon (PAH) with high genotoxicity and carcinogenicity. It is formed and released into the environment due to incomplete combustion of fossil fuel and various anthropogenic activities including cigarette smoke and automobile exhausts. The aim of present study is to isolate bacteria which can degrade BaP as a sole source of carbon and energy. We have isolated a novel strain BMT4i (MTCC 9447) of Bacillus subtilis from automobile contaminated soil using BaP (50 g /ml) as the sole source of carbon and energy in basal salt mineral (BSM) medium. The growth kinetics of BMT4i was studied using CFU method which revealed that BMT4i is able to survive in BaP-BSM medium up to 40 days attaining its peak growth (10(29) fold increase in cell number) on 7 days of incubation. The BaP degradation kinetics of BMT4i was studied using High Performance Liquid Chromatography (HPLC) analysis of BaP biodegradation products. BMT4i started degrading BaP after 24 hours and continued up to 28 days achieving maximum degradation of approximately 84.66 %. The above findings inferred that BMT4i is a very efficient degrader of BaP. To our best of knowledge, this is the first report showing utilization of BaP as a sole source of carbon and energy by bacteria. In addition, BMT4i can degrade a wide range of PAHs including naphthalene, anthracene, and dibenzothiophene therefore, it could serve as a better candidate for bioremediation of PAHs contaminated sites.

Chemical and microbiological characterization of mangrove sediments after a large oil-spill in Guanabara Bay - RJ - Brazil

Seventeen months after a 1,3 million L oil spill into Guanabara Bay, analyses of mangrove sediments showed that the three sites closest to the spill remain highly polluted (>10 µg-g-1 polyaromatic hydrocarbons). A fourth site was less polluted, from which most hydrocarbon degrading bacteria were isolated.

Dezessete meses após um derramamento de 1,3 milhões de litros de óleo na Baía de Guanabara, análises de sedimento do manguezal mostraram que os três pontos de amostragem mais próximos do local do acidente permanecem altamente poluídos (>10 µg-g-1 hidrocarbonetos poliaromáticos). Do quarto ponto de amostragem, o menos poluído, foi isolada a maioria das bactérias degradadoras de hidrocarbonetos.

Acute and subchronic effects of petroleum on the freshwater fish Hoplias aff. malabaricus

Abstract Petroleum water soluble fraction (WSF) impairs organisms, but damages may vary among cell and tissue levels. The aim of the present study was to evaluate the acute (24 h, 48 h, 72 h) and subchronic effects (36 days) of WSF (0%, 25% and 100%) in juveniles of the Neotropical top predator fish Hoplias aff. malabaricus. The effects of WSF were evaluated at a molecular level using the comet assay and micronucleus test for genome damage; and at a morphological level through histological identification of liver pathologic lesions. In both acute and subchronic exposure we found low levels of DNA damage ( 10% of comet tail) and non-significant frequency of micronucleus in WSF exposed fish. The most significant liver lesions in WSF exposed fish were fatty vacuolization, hypertrophy and focal necrosis. Since these tissue injuries were progressive and persistent, their irreversibility may negatively affect fish recruitment, even in a such resistant top predator.

Resumo A fração solúvel de petróleo (WSF) prejudica os organismos, porém os danos podem variar entre os níveis celular e tecidual. O objetivo do presente estudo foi avaliar o efeito agudo (24 h, 48 h e 72 h) e subcrônico (36 dias) da WSF (0%, 25% e 100%) em juvenis do peixe neotropical predador topo Hoplias aff. malabaricus. Os efeitos da WSF foram avaliados no nível molecular utilizando o ensaio do cometa e o teste do micronúcleo para o dano genômico e no nível morfológico através da identificação histológica de lesões patológicas no fígado. Em ambas exposições (aguda e subcrônica) encontramos baixos níveis de dano no DNA ( 10% de DNA na cauda do cometa) e frequência de micronúcleos não significativa em peixes expostos a WSF. As lesões mais significativas no fígado dos peixes expostos a WSF foram a vacuolização lipídica, hipertrofia e focos de necroses. Como estas lesões foram progressivas e persistentes, sua irreversibilidade pode afetar negativamente o recrutamento dos peixes, mesmo sendo um predador topo resistente.

Acute and subchronic effects of petroleum on the freshwater fish Hoplias aff. malabaricus / Efeitos agudo e subcrônico do petróleo no peixe de água doce Hoplias aff. malabaricus

Abstract Petroleum water soluble fraction (WSF) impairs organisms, but damages may vary among cell and tissue levels. The aim of the present study was to evaluate the acute (24 h, 48 h, 72 h) and subchronic effects (36 days) of WSF (0%, 25% and 100%) in juveniles of the Neotropical top predator fish Hoplias aff. malabaricus. The effects of WSF were evaluated at a molecular level using the comet assay and micronucleus test for genome damage; and at a morphological level through histological identification of liver pathologic lesions. In both acute and subchronic exposure we found low levels of DNA damage (< 10% of comet tail) and non-significant frequency of micronucleus in WSF exposed fish. The most significant liver lesions in WSF exposed fish were fatty vacuolization, hypertrophy and focal necrosis. Since these tissue injuries were progressive and persistent, their irreversibility may negatively affect fish recruitment, even in a such resistant top predator.

Resumo A fração solúvel de petróleo (WSF) prejudica os organismos, porém os danos podem variar entre os níveis celular e tecidual. O objetivo do presente estudo foi avaliar o efeito agudo (24 h, 48 h e 72 h) e subcrônico (36 dias) da WSF (0%, 25% e 100%) em juvenis do peixe neotropical predador topo Hoplias aff. malabaricus. Os efeitos da WSF foram avaliados no nível molecular utilizando o ensaio do cometa e o teste do micronúcleo para o dano genômico e no nível morfológico através da identificação histológica de lesões patológicas no fígado. Em ambas exposições (aguda e subcrônica) encontramos baixos níveis de dano no DNA (< 10% de DNA na cauda do cometa) e frequência de micronúcleos não significativa em peixes expostos a WSF. As lesões mais significativas no fígado dos peixes expostos a WSF foram a vacuolização lipídica, hipertrofia e focos de necroses. Como estas lesões foram progressivas e persistentes, sua irreversibilidade pode afetar negativamente o recrutamento dos peixes, mesmo sendo um predador topo resistente.