Project description:Background: Cyanobacteria are ecologically significant prokaryotes that can be found in heavy metals contaminated environments. As their photosynthetic machinery imposes high demands for metals, homeostasis of these micronutrients has been extensively considered in cyanobacteria. Recently, most studies have been focused on different habitats using microalgae leads to a remarkable reduction of an array of organic and inorganic nutrients, but what takes place in the extracellular environment when cells are exposed to external supplementation with heavy metals remains largely unknown. Methods: Here, extracellular polymeric substances (EPS) production in strains Nostoc sp. N27P72 and Nostoc sp. FB71 was isolated from different habitats and thenthe results were compared and reported . Result: Cultures of both strains, supplemented separately with either glucose, sucrose, lactose, or maltose showed that production of EPS and cell dry weight were boosted by maltose supplementation. The production of EPS (9.1 ± 0.05 μg/ml) and increase in cell dry weight (1.01 ± 0.06 g/l) were comparatively high in Nostoc sp. N27P72 which was isolated from lime stones.The cultures were evaluated for their ability to remove Cu (II), Cr (III), and Ni (II) in culture media with and without maltose. The crude EPS showed metal adsorption capacity assuming the order Ni (II)> Cu (II)> Cr (III) from the metal-binding experiments .Nickel was preferentially biosorbed with a maximal uptake of 188.8 ± 0.14 mg (g cell dry wt) -1 crude EPS. We found that using maltose as a carbon source can increase the production of EPS, protein, and carbohydrates content and it could be a significant reason for the high ability of metal absorbance. FT-IR spectroscopy revealed that the treatment with Ni can change the functional groups and glycoside linkages in both strains. Results of Gas Chromatography-Mass Spectrometry (GC–MS) were used to determine the biochemical composition of Nostoc sp. N27P72, showed that strong Ni (II) removal capability could be associated with the high silicon containing heterocyclic compound and aromatic diacid compounds content.

Project description:Background: Cyanobacteria are ecologically significant prokaryotes that can be found in heavy metals contaminated environments. As their photosynthetic machinery imposes high demands for metals, homeostasis of these micronutrients has been extensively considered in cyanobacteria. Recently, most studies have been focused on different habitats using microalgae leads to a remarkable reduction of an array of organic and inorganic nutrients, but what takes place in the extracellular environment when cells are exposed to external supplementation with heavy metals remains largely unknown. Methods: Here, extracellular polymeric substances (EPS) production in strains Nostoc sp. N27P72 and Nostoc sp. FB71 was isolated from different habitats and thenthe results were compared and reported . Result: Cultures of both strains, supplemented separately with either glucose, sucrose, lactose, or maltose showed that production of EPS and cell dry weight were boosted by maltose supplementation. The production of EPS (9.1 ± 0.05 μg/ml) and increase in cell dry weight (1.01 ± 0.06 g/l) were comparatively high in Nostoc sp. N27P72 which was isolated from lime stones.The cultures were evaluated for their ability to remove Cu (II), Cr (III), and Ni (II) in culture media with and without maltose. The crude EPS showed metal adsorption capacity assuming the order Ni (II)> Cu (II)> Cr (III) from the metal-binding experiments .Nickel was preferentially biosorbed with a maximal uptake of 188.8 ± 0.14 mg (g cell dry wt) -1 crude EPS. We found that using maltose as a carbon source can increase the production of EPS, protein, and carbohydrates content and it could be a significant reason for the high ability of metal absorbance. FT-IR spectroscopy revealed that the treatment with Ni can change the functional groups and glycoside linkages in both strains. Results of Gas Chromatography-Mass Spectrometry (GC–MS) were used to determine the biochemical composition of Nostoc sp. N27P72, showed that strong Ni (II) removal capability could be associated with the high silicon containing heterocyclic compound and aromatic diacid compounds content. Conclusion: The results of this studyindicatede that strains Nostoc sp. N27P72 can be a good candidate for the commercial production of EPS and might be utilized in bioremediation field as an alternative to synthetic and abiotic flocculants.

Project description:Our main objectives were: 1) to identify transcriptional signatures specific to the exposure to two metals: Ni and Cd; 2) to investigate the mechanisms of toxicity for these two metals; and 3) to develop a predictive tool to identify the sublethal effects of Ni and Cd contaminants in fish sampled from natural environments. The molecular mechanisms underlying nickel (Ni) and cadmium (Cd) toxicity and their specific effects on fish are poorly understood. Documenting gene transcription profiles offers a powerful approach towards identifying the molecular mechanisms affected by these metals and to discover biomarkers of their toxicity. However, confounding environmental factors can complicate the interpretation of the results and the detection of biomarkers for fish captured in their natural environment. In the present study, a 1000 candidate-gene microarray, developed from a previous RNA-seq study on a subset of individual fish from contrasting level of metal contamination, was used to investigate the transcriptional response to metal (Ni and Cd) and non metal (temperature, oxygen, and diet) stressors in yellow perch (Perca flavescens). Specifically, we aimed at 1) identifying transcriptional signatures specific to Ni and Cd exposure, 2) investigating the mechanisms of their toxicity, and 3) developing a predictive tool to identify the sublethal effects of Ni and Cd contaminants in fish sampled from natural environments. A total of 479 genes displayed significantly different transcription levels when temperature varied while 287 and 177 genes were differentially transcribed at different concentrations of Ni and Cd, respectively. These metals were found to mainly affect the transcription level of genes involved in iron metabolism, transcriptional and translational processes, vitamin metabolism, blood coagulation, and calcium transport. In addition, a linear discriminant analysis (LDA) made using gene transcription levels yielded 94% correctly reassigned samples regarding their level of metal contamination, which indicates the potential of the microarray to detect perch response to Cd or Ni effects.

Project description:Pentavalent vanadium compounds induce intracellular changes in vitro that are consistent with those of other carcinogenic substances, including alteration of transcription factor levels, promotion of oxidative stress, inflammation, DNA damage, stimulation of mitogenic signals, and suppression of apoptosis. While there is no clear evidence that vanadium compounds cause cancer in humans, vanadium pentoxide causes lung cancer in rodents after long-term inhalation exposures and in turn IARC has categorized it as a group 2B possible human carcinogen. The goal of this study was to investigate the carcinogenicity of NaVO3 in the human immortalized bronchial epithelial cell line, Beas-2B. Cells were treated with 10 M-BM-5M NaVO3 for 5 weeks, with or without recovery time, followed by gene expression microarray analysis. In a separate experiment, cells were exposed to 1-10 M-BM-5M NaVO3 for 4 weeks and then grown in soft agar to test for anchorage-independent growth. A dose-dependent increase in the number of colonies was observed. NaVO3-transformed clones could repair a wound faster than controls during the scratch test. In a gene expression microarray analysis of soft agar clones there were 2010 differentially expressed genes (DEG) (adjusted p-value M-bM-^IM-$ 0.05) in NaVO3-transformed clones relative to control clones. DEG from this experiment were compared with the DEG of 5 week NaVO3 exposure with or without recovery, all with adjusted p-values <0.05, and 469 genes were altered in the same direction for transformed clones, 5 week NaVO3-treated cells, and the recovered cells; a subset of these changes were validated by QRT-PCR. The data from this study imply that chronic exposure to NaVO3 causes changes that are consistent with cellular transformation including anchorage- independent growth, enhanced migration ability, and gene expression changes that were epigenetically inherited through cell division. Beas-2B cells were chronically exposed to sodium metavanadate in growth media for 4 weeks. Then, one set of exposed cells and unexposed control cells were grown in soft agar for 3 weeks in the absence of vanadate. Transformed colonies (arising from vanadate-exposed cells) and control colonies (spontaneously grew from unexposed cells) were extracted from soft agar and expanded in the absence of vanadate, then processed for gene expression analysis . A second set of exposed cells continued treatment for a total of 5 weeks exposure. A third set of cells recovered for 1 week after the 4 week long exposure. The gene expression of 5 transformed clones, 3 control clones, 2 5 week exposures, 2 recovery, and 2 unexposed control cells, and 1 parental Beas-2B cell samples were analyzed (15 total samples) with an Affymetrix GeneChip Human Exon 1.0 ST array.

Project description:Our main objectives were: 1) to identify transcriptional signatures specific to the exposure to two metals: Ni and Cd; 2) to investigate the mechanisms of toxicity for these two metals; and 3) to develop a predictive tool to identify the sublethal effects of Ni and Cd contaminants in fish sampled from natural environments. The molecular mechanisms underlying nickel (Ni) and cadmium (Cd) toxicity and their specific effects on fish are poorly understood. Documenting gene transcription profiles offers a powerful approach towards identifying the molecular mechanisms affected by these metals and to discover biomarkers of their toxicity. However, confounding environmental factors can complicate the interpretation of the results and the detection of biomarkers for fish captured in their natural environment. In the present study, a 1000 candidate-gene microarray, developed from a previous RNA-seq study on a subset of individual fish from contrasting level of metal contamination, was used to investigate the transcriptional response to metal (Ni and Cd) and non metal (temperature, oxygen, and diet) stressors in yellow perch (Perca flavescens). Specifically, we aimed at 1) identifying transcriptional signatures specific to Ni and Cd exposure, 2) investigating the mechanisms of their toxicity, and 3) developing a predictive tool to identify the sublethal effects of Ni and Cd contaminants in fish sampled from natural environments. A total of 479 genes displayed significantly different transcription levels when temperature varied while 287 and 177 genes were differentially transcribed at different concentrations of Ni and Cd, respectively. These metals were found to mainly affect the transcription level of genes involved in iron metabolism, transcriptional and translational processes, vitamin metabolism, blood coagulation, and calcium transport. In addition, a linear discriminant analysis (LDA) made using gene transcription levels yielded 94% correctly reassigned samples regarding their level of metal contamination, which indicates the potential of the microarray to detect perch response to Cd or Ni effects. Comparison between fish exposed to three temperatures (11, 20, 28M-BM-0C) using a loop design, comparison between control fish and fich exposed to restrictive diet using a pairwise design, comparison between fish exposed to hypoxia and control fish, comparison between fish exposed to two concentrations of cadmium and control fish using a loop design, and comparison between fish exposed to two concentrations of nickel and control fish using a loop design.

Dataset Information

Exposure of an immortalized human bronchial epithelial cell line, BEAS-2B, to one of four metals (arsenic, chromium, nickel or vanadium) to determine the early changes that lead to cell transformation

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