Project description:Silver nanoparticles (NPs) are extensively used due to their antimicrobial activity and, therefore, their input into the ecosystem will increase. Silver can be bioaccumulated by low trophic level organisms and, then, incorporated into the food chain, reaching high level predators. The objectives of this study were to test the acute toxicity of N-vynil-2-pirrolidone/polyethylenimine (PVP-PEI) coated Ag NPs of 5 nm to brine shrimp (Artemia sp) larvae and to assess bioaccumulation and effects of silver transferred by the diet. For the later, brine shrimps were exposed to two different concentrations of Ag NPs, 100 ng/L as an environmentally relevant concentration and 100 µg/L as a likely effective concentration, in parallel with an unexposed control group and, then, used to feed zebrafish during 21 days in order to simulate two trophic levels of a simplified food web. For brine shrimp larvae, EC50 values ranged from 7.39 mg Ag/L (48 h post hatch larvae (hph) exposed for 48 h) to 19.63 mg Ag/L (24 hph larvae exposed for 24 h. Silver accumulation was measured in brine shrimps exposed to 0.1 and 1 mg/L of Ag NPs for 24 h. In zebrafish fed with brine shrimps exposed to Ag NPs, intestine showed higher metal accumulation than liver, although both organs presented the same pattern of dose and time-dependent metal accumulation as revealed by autometallography. Feeding of zebrafish for 3 days with brine shrimps exposed to 100 ng/L of Ag NPs was enough to impair fish health as reflected by the significant reduction of the lysosomal membrane stability and the presence of several histopathological conditions in the liver. Overall, results showed that Ag NPs were able to exert toxic effects on zebrafish through dietary exposure, even at an environmentally relevant concentration, which should act as concern of the need of studies in further detail about real impact of nanomaterials in the environment.
Project description:Sequencing the metatranscriptome can provide information about the response of organisms to varying environmental conditions. We present a methodology for obtaining random whole-community mRNA from a complex microbial assemblage using Pyrosequencing. The metatranscriptome had, with minimum contamination by ribosomal RNA, significant coverage of abundant transcripts, and included significantly more potentially novel proteins than in the metagenome. Keywords: metatranscriptome, mesocosm, ocean acidification
2008-02-08 | GSE10119 | GEO
Project description:Transcriptome of sexual and asexual Artemia brine shrimp
Project description:The phenomenon of trained immunity, which facilitates vaccine development for disease control, has been identified in shrimp; however, the mechanism remains elusive. In the present study, we found that histone H3K27 acetylation (H3K27ac) mediated by the lysine acetyltransferase KAT8 plays an important role in preventing white spot syndrome virus (WSSV) infection in the shrimp Marsupenaeus japonicus. We then successfully established a model of trained immunity via the use of UV-inactivated WSSV to explore the underlying mechanism(s) in shrimp. In UV-WSSV-trained shrimp, the glycolysis and tricarboxylic acid (TCA) cycle metabolic pathways were enhanced and acetyl-CoA concentrations were increased. As the acetyl group donor, acetyl-CoA promotes KAT8 activity to increase H3K27 acetylation. H3K27ac is deposited at the promoter region of the transcription factor Dorsal to facilitate its expression and then Dorsal promotes the expression of an interferon-like cytokine, Vago5, and antimicrobial peptides that act against WSSV infection. H3K27ac is also deposited at the promoter region of hexokinase 2 and isocitrate dehydrogenase, which positively regulates glycolysis and the TCA cycle in a feedforward manner. Our results reveal a novel mechanism of trained immunity induced by UV-WSSV in shrimp and provide a theoretical basis for the development of antiviral vaccines for disease control in shrimp aquaculture.
Project description:This project aimed at evaluating the preservation of cell envelope extract from H. salinarum incubated in brines of different composition when exposed UVC irradiation. The evaluation of preservation properties was performed by assessing the membrane protein degradation occurring in each brine through mass spectrometry.