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:Chemical communication is crucial in ecosystems with complex microbial assemblages. However, due to archaeal cultivation challenges, our understanding of the structure diversity and function of secondary metabolites (SMs) within archaeal communities is limited compared to the extensively studied and well-documented bacterial counterparts. Our comprehensive investigation into the biosynthetic potential of archaea, combined with metabolic analyses and the first report of heterologous expression in archaea, has unveiled the previously unexplored biosynthetic capabilities and chemical diversity of archaeal ribosomally synthesized and post-translationally modified peptide (RiPP). We have identified twenty-four new lanthipeptides of RiPPs exhibiting unique chemical characteristics, including a novel subfamily featuring an unexplored type with diamino-dicarboxylic (DADC) termini, largely expanding the chemical landscape of archaeal SMs. This sheds light on the chemical novelty of archaeal metabolites and emphasizes their potential as an untapped resource for natural product discovery. Additionally, archaeal lanthipeptides demonstrate specific antagonistic activity against haloarchaea, mediating the unique biotic interaction in the halophilic niche. Furthermore, they showcased a unique ecological role in enhancing the host's motility by inducing the rod-shaped cell morphology and upregulating the archaellum gene flgA1, facilitating the archaeal interaction with abiotic environments. These discoveries broaden our understanding of archaeal chemical language and provide promising prospects for future exploration of SM-mediated interaction.
Project description:Ammonia-oxidizing archaeal (AOA) amoA diversity and relative abundance in Gulf of Mexico sediments (0-2 cm) were investigated using a functional gene microarray; a two color array with a universal internal standard
2013-03-01 | GSE42286 | GEO
Project description:Halophilic archaeal diversity in brine from East Taigener Salt Lake was assessed by amplicon