Identification of contamination in estuarine ecosystems that are impacted by anthropogenic pressures, such as the Seine estuary, is difficult to determine without considering the role environmental ...variation plays on the end points selected. Currently, there is interest in identifying methods in which the influence of confounding factors can be described and accounted for. In this context, the aim of this study was to define a baseline assessment criteria (BAC) for enzymatic biomarkers in ragworms (Hediste diversicolor) collected in a reference site (Authie). The model took into consideration the weight, temperature and salinity of the site. Values collected in the Seine estuary were analyzed with the model to determine if differences between the sites could potentially be due to contamination or were explained by environmental variation. In general, biomarker responses from the Seine estuary fell within the range of BAC, suggesting that environmental variation could explain some of the results.
•Thresholds for biomarkers•Multiple polynomial regression model to integrate confounding factors•Characterization of polluted site using model
Les nanotechnologies représentent un domaine émergent considéré comme la révolution industrielle du 21ème siècle. Les nanomatériaux manufacturés (NMs) vont se retrouver inévitablement dans ...l’environnement aquatique. Dans un contexte de règlementation des NMs, l’objectif est d’utiliser des approches de lecture croisée pour regrouper les NMs selon différents critères. Pour cela, l’utilisation du criblage à haut debit représente un grand interêt puisque cet outil permet de tester un grand nombre de NMs, à moindre coût. La réglementation est aussi axée sur le concept du safe(r)-by-design (SbD) dans la production des NMs. Ainsi, dans ce travail de thèse, une plateforme HTS basée sur les hémocytes de moule Mytilus edulis a été développée, permettant la mesure de paramètres de viabilité cellulaire ainsi que de l'expression des gènes. Des études de cas proposés par des industriels ont été menés en utilisant cette approche in vitro. En parallèle, une approche in vivo a été menée afin de déterminer si ces deux stratégies aboutiraient aux mêmes conclusions quant à l’aspect SbD des NMs. Par ailleurs, une large gamme de NMs a été testée afin d’établir des bases de données pour regrouper les NMs, basé sur la viabilité cellulaire des hémocytes. Ce travail démontre la pertinaence d’utiliser les approaches HTS chez M. edulis pour évaluer le risque environnemental lié aux NMs. En outre, l’expression des gènes représentent un paramétrè prometteur pour determiner les modes d’action de la toxicité des NMs. L’ensemble de ces résultats a permis de générer une base de donnée préliminaire en écotoxicologie qui pourrait être utilisée dans un contexte de réglementation des NMs.
Nanotechnology is an emerging field that is considered the industrial revolution of the 21st century. In this context, Manufactured nanomaterials (MNMs) will inevitably be released into the aquatic environment. In the objective of MNM regulation, the aim is to implement a read-across (grouping) approach based on high throughput screening (HTS) techniques as a way of quickly prescreening many MNMs in a cost-effective manner. Regulation is also focused on developing safe(r)-by-design (SbD) concept to integrate safety into the production of products. In this sense, for this work, an HTS platform on Mytilus edulis hemocytes has been developed using endpoints for cell viability as well as gene expression. Industrial case studies were investigated in in vitro testing following the HTS approach. In parallel an in vivo approach was assessed to determine if both testing strategies would come to the same conclusions on which product was SbD. In addition, a wide array of MNMs were also tested for effects on cell viability to establish a relevant database to investigate a grouping approach for MNM. This work demonstrated the relevance of using an HTS platform for M. edulis hemocytes to prescreen MNMs for environmental risk. Gene expression also provides a promising framework for investigating modes actions for MNM toxicity as well as the potential to develop adverse outcome pathways for SbD. This thesis established a preliminary database for ecotoxicology that could be implemented in a regulatory approach for NMs.
To have an understanding of potential mechanistic effects, sublethal endpoints able to discriminate between nanomaterials with similar physical and chemical features need to be used. In this sense, ...quantitative PCR was used to measure a battery of genes linked to a wide array of different cellular processes. Gene expression was measured in Mytilus edulis hemocytes following an in vitro and in vivo exposure to pure silicon (40 nm) and carbon-coated silicon (40 and 75 nm) after 24 h. Partial least squares discriminant analysis and correlation analysis were used to develop an integrative model, describing the relationship between genes, to identify which genes were important in describing responses to engineered nanomaterial exposure. The results suggested that some discriminations could be made based on the presence of a carbon coating or the alteration of size which could inform industrial patterns on ways to reduce the ecotoxicological impact of their product. The results also indicate that HTS on Mytilus hemocytes may be integrated into a safer-by-design approach but additional characterization of nanomaterial behavior in media is required to determine if it is a suitable alternative to in vivo testing.
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•Ecotoxicological hazard assessment of silicon and carbon coated silicon through qPCR.•Comparison of in vitro and in vivo exposures for M. edulis hemocytes.•Correlational analysis of product features to gene expression.
Investigates the induction of metallothionein (MT) in the common bully, Gobiomorphus cotidianus, to assess exposure to trace metal contamination in the Motueka River. Shows a significant increase in ...MT induction in both the gill and liver tissue samples from fish collected in the Motueka River compared to a reference site in the Brooklyn Stream tributary. Source: National Library of New Zealand Te Puna Matauranga o Aotearoa, licensed by the Department of Internal Affairs for re-use under the Creative Commons Attribution 3.0 New Zealand Licence.
The Matāura River is the sixth largest river system in New Zealand and has long been subject to agricultural, industrial, and residential land use activities. The catchment has economic value and is ...of great cultural importance for local Māori, who have concerns over potential adverse impacts that anthropogenic stressors exert on the health of the river. There is a dearth of information on the impacts of these stressors towards the health of native species such as the longfin eel Anguilla dieffenbachii. This study assessed the environmental status of the Matāura River using biological and chemical methodologies incorporating A. dieffenbachii as a bioindicator species for exposure to multiple anthropogenic stressors. A range of biomarkers were measured in caged and wild-caught eels (when available) to characterize site-specific responses to anthropogenic stressors. While there was no clear indication of cumulative impacts moving from pristine headwaters to the lower reaches of the Matāura River, biomarkers of xenobiotic metabolization were induced in A. dieffenbachia and there was evidence of chemical contamination in sediment and tissue samples.
The implementation of Safe(r) by Design (SbD) in industrial innovations requires an integrated approach where the human, environmental and economic impact of the SbD measures is evaluated across and ...throughout the nanomaterial (NM) life cycle. SbD was implemented in six industrial companies where SbD measures were applied to NMs, nano-enabled products (NEPs) and NM/NEP manufacturing processes.
The approach considers human and environmental risks, functionality of the NM/NEP and costs as early as possible in the innovation process, continuing throughout the innovation progresses. Based on the results of the evaluation, a decision has to be made on whether to continue, stop or re-design the NM/NEP/process or to carry out further tests/obtain further data in cases where the uncertainty of the human and environmental risks is too large. However, SbD can also be implemented at later stages when there is already a prototype product or process available, as demonstrated in some of the cases.
The SbD measures implemented in some of the case studies did not result in a viable solution. For example the coating of silicon nanoparticles with amorphous carbon increased the conductivity, the stability and reduced the dustiness of the particles and therefore the risk of explosion and the exposure to workers. However the socioeconomic assessment for their use in lithium-ion batteries for cars, when compared to the use of graphite, showed that the increase in performance did not overcome the higher production costs.
This work illustrates the complexities of selecting the most appropriate SbD measures and highlights that SbD cannot be solely based on a hazard and exposure assessment but must include other impacts that any SbD measures may have on sustainability including energy consumption and waste generation as well as all associated monetary costs.
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•SbD implementation in real industrial case studies in the nanotechnology sector.•Application of existing Risk Assessment, Life-Cycle Assessment and Socio-Economic Assessment tools to SbD SbD concept for NMs and NEPs•SbD concept for NMs and NEPs and edited the second higlight
The Motueka catchment is a major river system in the South Island, New Zealand, typically considered to be of 'good water quality'. The catchment has high metal inputs originating from a mineral belt ...in the headwaters. This study investigated the induction of metallothionein (MT) in the common bully, Gobiomorphus cotidianus, to assess exposure to trace metal contamination in the Motueka River. The results showed a significant increase in MT induction in both the gill and liver tissue samples from fish collected in the Motueka River compared to a reference site in the Brooklyn Stream tributary. This effect is likely modulated by the higher nickel levels originating from the Red Hills that accumulated in the sediment of the Motueka River.
Cerebral small vessel disease (SVD) is a common cause of vascular cognitive impairment. A number of disease features can be assessed on MRI including lacunar infarcts, T2 lesion volume, brain ...atrophy, and cerebral microbleeds. In addition, diffusion tensor imaging (DTI) is sensitive to disruption of white matter ultrastructure, and recently it has been suggested that additional information on the pattern of damage may be obtained from axial diffusivity, a proposed marker of axonal damage, and radial diffusivity, an indicator of demyelination. We determined the contribution of these whole brain MRI markers to cognitive impairment in SVD. Consecutive patients with lacunar stroke and confluent leukoaraiosis were recruited into the ongoing SCANS study of cognitive impairment in SVD (n = 115), and underwent neuropsychological assessment and multimodal MRI. SVD subjects displayed poor performance on tests of executive function and processing speed. In the SVD group brain volume was lower, white matter hyperintensity volume higher and all diffusion characteristics differed significantly from control subjects (n = 50). On multi-predictor analysis independent predictors of executive function in SVD were lacunar infarct count and diffusivity of normal appearing white matter on DTI. Independent predictors of processing speed were lacunar infarct count and brain atrophy. Radial diffusivity was a stronger DTI predictor than axial diffusivity, suggesting ischaemic demyelination, seen neuropathologically in SVD, may be an important predictor of cognitive impairment in SVD. Our study provides information on the mechanism of cognitive impairment in SVD.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Honey bees are essential pollinators threatened by colony losses linked to the spread of parasites and pathogens. Here, we report a new approach for manipulating bee gene expression and protecting ...bee health. We engineered a symbiotic bee gut bacterium,
, to induce eukaryotic RNA interference (RNAi) immune responses. We show that engineered
can stably recolonize bees and produce double-stranded RNA to activate RNAi and repress host gene expression, thereby altering bee physiology, behavior, and growth. We used this approach to improve bee survival after a viral challenge, and we show that engineered
can kill parasitic
mites by triggering the mite RNAi response. This symbiont-mediated RNAi approach is a tool for studying bee functional genomics and potentially for safeguarding bee health.
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