104,777 research outputs found
Expression analysis of the molluscan p53 protein family mRNA in mussels (Mytilus spp.) exposed to organic contaminants
No full textIn this study, we report the tissue expression analysis of the p53 protein family mRNA in mussels (Mytilus spp.) by means of quantitative RT-PCR. The tissue specific response was evaluated after 24 h exposure to a sublethal benzo[a]pyrene (B[a]P) concentration (75 nM), showing a 2.6 fold induction in digestive gland cells and a dramatic gene down regulation in circulating hemocytes. The comet assay and DNA gel diffusion tests showed significant effects in hemocytes and negligible differences in the digestive gland nuclei, implicating p53 in DNA damage of molluscan hemocytes. Finally, the kinetics of p53 protein family mRNA expression in the digestive gland of animals exposed to B[a]P and crude oil (0.5 ppm) showed partially overlapping trends, characterised by a common down regulation after 1 week exposure. These data should be carefully considered in view of the biological effects of organic pollutants and particularly following spills
Expression analysis of the molluscan p53 protein family mRNA in mussels (Mytilus spp.) exposed to organic contaminants
No full textIn this study, we report the tissue expression analysis of the p53 protein family mRNA in mussels (Mytilus spp.) by means of quantitative RT-PCR. The tissue specific response was evaluated after 24 h exposure to a sublethal benzo[a]pyrene (B[a]P) concentration (75 nM), showing a 2.6 fold induction in digestive gland cells and a dramatic gene down regulation in circulating hemocytes. The comet assay and DNA gel diffusion tests showed significant effects in hemocytes and negligible differences in the digestive gland nuclei, implicating p53 in DNA damage of molluscan hemocytes. Finally, the kinetics of p53 protein family mRNA expression in the digestive gland of animals exposed to B[a]P and crude oil (0.5 ppm) showed partially overlapping trends, characterised by a common down regulation after 1 week exposure. These data should be carefully considered in view of the biological effects of organic pollutants and particularly following spills
Assessment of heavy metal contamination using real-time PCR analysis of mussel metallothionein mt10 and mt20 expression: a validation along the Tunisian coast
No full textApplication of silane only selective epitaxy to the fabrication of fully self-aligned silicon bipolar transistors
No full textMixture Toxicity Assessment of Nickel and Chlorpyrifos in the Sea Bass Dicentrarchus labrax
No full textThe present research work was designed to study Dicentrarchus labrax biotransformation and detoxification responses to acute exposure to nickel (Ni) and chlorpyrifos (CHP). Sexually immature sea bass were treated by intraperitoneal injection of nickel chloride (500 μg kg−1), chlorpyrifos (10 mg kg−1), and their binary mixture for 1, 3, and 7 days. Ni and CHP accumulation was quantified in liver after the exposure periods. The following biological responses were measured: (1) NADPH cytochrome P450 reductase (NCR) activity, as phase I biotransformation parameter; (2) gluthathione S-transferase (GST) activity as a phase II conjugation enzyme, acetylcholinesterase activity, and metallothionein (MT) content. Ni bioaccumulation in the liver resulted in an increasing uptake up to 15.48 μg g−1 wet weight (Ni-treated animals) and 16.73 μg g−1 wet weight (mixture-treated animals) after 7 days of exposure. CHP accumulation showed a distinct pattern in animals exposed to the mixture of chemicals in comparison with CHP-treated animals. NCR activity exhibited a marked activation in CHP and mixture-treated animals. GST activity was significantly increased starting from 1 day exposure in CHP-treated animals and after 3 days in Ni-treated animals. MT accumulation increased in all conditions, with a marked synergetic effect after 7 days of exposure. These data should be carefully considered in view of the biological effects of mixture pollutants, particularly in fish farming conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effects of thermal stress and nickel exposure on biomarkers responses in Mytilus galloprovincialis (Lam).
No full textThe present work aimed to assess the Mytilus galloprovincialis digestive gland biomarkers responses to nickel (Ni) exposure along with a heat stress gradient. Mussels were exposed to a sublethal dose of nickel (13 μM) along with a temperature gradient (18 °C, 20 °C, 22 °C, 24 °C and 26 °C) for 4 days. Metallothionein (MTs) content was assessed as specific response to metals. Catalase (CAT), glutathione S-transferase (GST) activities and malondialdehyde (MDA) were measured as biomarkers of oxidative stress and lipid peroxidation. The cholinergic system was monitored using the acetylcholinesterase activity (AChE). Moreover, Ni uptakes along with the exposure temperatures were assessed. A correlation matrix (CM) between the investigated biomarkers and the exposure temperatures and a Principal Component Analysis (PCA) were achieved. Our data showed a negative effect of temperature increase on mussel's antioxidant and detoxification response to Ni exposure being more pronounced in animals exposed to the 24 °C and 26 °C
Uptake and biochemical responses of mussels Mytilus galloprovincialis exposed to sublethal nickel concentrations.
No full textTranscriptional expression levels and biochemical markers of oxidative stress in Mytilus galloprovincialis exposed to nickel and heat stress.
No full textThe present study aims to evaluate transcriptional expression levels and biochemical markers of oxidative stress responses to nickel (Ni) exposure along with heat stress gradient in a mussel (Mytilus galloprovincialis). For this purpose, we investigated the response of oxidative stress markers, metallothionein accumulation and gene expression in digestive gland of mussels exposed to a sublethal concentration of Ni (2.5μM) along with a temperature gradient (18°C, 22°C, and 26°C) for 24h and 72h. Ni digestive gland uptake was evaluated after the exposure periods. Co-exposure to Ni and higher temperature (26°C) for 72h significantly decreased the antioxidant enzyme activities termed as catalase (CAT), superoxide dismutase (SOD) and glutathione-S-transferase (GST) and caused a pronounced increase of lipofuscin and neutral lipid (NL) accumulation. Ni-uptake was different with respect to the exposure periods and temperatures in Ni-exposed mussels. Sod, cat, gst, mt-10 and mt20 gene expression levels showed a substantial increased pattern in animals exposed for one day to heat stress compared to the control condition (18°C). The same pattern but with highest level was registered in animals co-exposed to Ni and temperatures within one day. Three days exposure to 18°C, 22°C and 26°C, resulted in a significant decrease in mRNA abundance of cat, gst and sod and a significant down-regulation of mts targets (22°C and 26°C). Our data provide new insights into the importance of the early protective response of oxidative stress related-gene expression and regulation in mussels challenging heat stress and sublethal Ni concentration
Transcriptional expression levels and biochemical markers of oxidative stress in the earthworm Eisenia andrei after exposure to 2,4-dichlorophenoxyacetic acid (2,4-D)
No full textThis study investigated the stress response of earthworms (Eisenia andrei) to exposure to a commonly used herbicide, 2,4 dichloro-phenoxy-acetic acid (2,4-D). We evaluated both stress biomarkers and the transcriptional expression levels and activity of three enzymes involved in oxidative stress responses. Earthworms were exposed to three sublethal concentration of 2,4-D (3.5, 7, and 14mgkg(-1)) for 7 and 14 days. Exposure to 7 and 14mgkg(-1) 2,4-D significantly reduced both worm body weight and lysosomal membrane stability (LMS); the latter is a sensitive stress biomarker in coelomocytes. Exposure to 2,4-D caused a pronounced increase in the accumulation of malonedialdehyde (MDA), a marker of oxidative stress, and significantly increased the activity of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD),and glutathione-S-transferase (GST). Compared to expression in controls, the expression levels of the sod, cat, and gst genes increased in worms exposed to all three 2,4-D doses for 7 days. However, after 14 days of exposure, only the expression of the gst gene remained higher than controls. These data provide new insights into the cytotoxicity of 2,4-D in the earthworm E. andrei and should be carefully considered in view of the biological effects of herbicides in soils organisms
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