MARTINS Jean (CNRS – Univ. Grenoble Alpes, FRANCE)

First Name: Jean

Name: MARTINS

Position: DR CNRS

Email: jean.martins@univ-grenoble-alpes.fr

Institute / University / Company: CNRS – Univ. Grenoble Alpes

Research Unit: IGE UMR 5001

Address (city, state): 70 rue de la physique, 38400 St Martin d’Hères

Country: France

Please give 5 key-words showing your research / interest in Microbial Ecotoxicolgy:

  • Soil and waterBacterial
  • cells dissemination
  • Impact of pollutants
  • Bioremediation

Main kinds of contaminant(s) of interest:

  • Heavy Metals
  • Pesticides
  • PAH
  • Emerging Polluants : pharmaceuticals, flame retardants, pathogens, nanoparticles

Main kinds of microorganisms of interest:

  • Soil and water community approaches
  • Pathogenic bacteria
  • Biofilm forming bacteria and archea
  • Bacterial whole cell sensors (gfp, lux, …)
  • Biomineralizing bacteria

Main kinds of ecosystems of interest:

  • Soil
  • water
  • Air
  • Organic Wastes
  • Plastics

Do you give courses on Microbial Ecotoxicology ?: YES

If yes, please tell us more about the courses (University, course level,website,etc): Univ. Grenoble Alpes, Master 1 & 2, UFR PHITEM, 9H.

Most relevant articles in the field of Microbial Ecotoxicology (max.5):

– Simonin M., J.M.F. Martins, X. Le Roux, G. Uzu, A. Calas and A. Richaume. Toxicity of TiO2 nanoparticles on soil nitrification at environmentally relevant concentrations: Lack of classical dose–response relationships. Nanotoxicol. DOI:10.1080/17435390.2017.1290845. 2017.
– Navel A. and J.M.F. Martins. E. Effect of long term organic amendments and vegetation of vineyard soils on the microscale distribution and biogeochemistry of copper. Sci. Total Environ. 466: 681-689. 2014.
– Desaunay A. and J.M.F. Martins. A physical cell-fractionation approach to assess the surface adsorption and internalization of cadmium by Cupriavidus metallidurans CH34. J. Haz. Mat. 273: 231-238. 2014.
– Martins J.M.F., S. Majdalani, E. Vitorge, A. Desaunay, A. Navel, V. Guiné, J.F. Daïan, E. Vince, H. Denis and J.P. Gaudet. Importance of macropore flow for the transport of Escherichia coli cells in undisturbed cores of a brown leached soil. Environ. Sci.: Processes Impacts, 15: 347-356. 2013.
– Lejon D.P.H., J.M.F. Martins, J. Lévêque, L. Spadini, N. Pascault, D. Landry, R. Chaussod, and L. Ranjard. Copper dynamics and impact on microbial communities in vineyard soils of variable organic status. Environ. Sci. Technol. 42(8): 2819-2825. 2008.

GOSSET Antoine (ENTPE,Vaulx-en-Velin, FRANCE)

Gosset

First Name: Antoine

Name: Gosset

Position: Post-doctoral researcher

Email: antoine.gosset@entpe.fr

Institute / University / Company: ENTPE

Research Unit: UMR CNRS 5023 LEHNA

Address (city, state): 3 rue Maurice Audin, 6120 Vaulx-en-Velin

Country: France

Please give 5 key-words showing your research / interest in Microbial Ecotoxicolgy:

  • Microalgae
  • Bioassay
  • Biosensor
  • Fluorescence
  • Ecotoxicity

Main kinds of contaminant(s) of interest:

  • Metals
  • Pesticides
  • Pharmaceuticals
  • Organic pollutants

Main kinds of microorganisms of interest:

  • Microalgae
  • Chlorella vulgaris
  • Pseudokirchneriella subcapitata
  • Chlamydomonas reinhardtii

Main kinds of ecosystems of interest: Freshwater ecosystems

Do you give courses on Microbial Ecotoxicology ?: YES

If yes, please tell us more about the courses (University, course level,website,etc): ENTPE/ENSMSE/INSA Lyon
Master Students

Most relevant articles in the field of Microbial Ecotoxicology (max.5):

KIM TIAM Sandra (MNHN, Paris, France)

MCAM

First Name: Sandra

Name: KIM TIAM

Position: Researcher

Email: sandra.kim-tiam-fook-chong@mnhn.fr

Institute / University / Company: MNHN

Research Unit: MCAM/CEE

Address (city, state): 12 rue Buffon

Country: France

Please give 5 key-words showing your research / interest in Microbial Ecotoxicolgy:

  • omics
  • metabolomic
  • transcriptomic

Main kinds of contaminant(s) of interest:

  • pesticides
  • metals
  • cyanotoxins
  • mixtures

Main kinds of microorganisms of interest:

  • cyanobacteria
  • diatoms
  • biofilms

Main kinds of ecosystems of interest:

  • rivers
  • lakes

Do you give courses on Microbial Ecotoxicology ?: YES

If yes, please tell us more about the courses (University, course level,website,etc): MNHN, master, diatoms and biofilms as bioindicators

Most relevant articles in the field of Microbial Ecotoxicology (max.5):

FREIXA Anna (Catalan Institute for Water Research, ICRA,Girona, SPAIN)

Freixa

First Name: Anna

Name: Freixa

Position: PostDoc researcher

Email: afreixa@icra.cat

Institute / University / Company: Catalan Institute for Water Research ( ICRA)

Research Unit: Resources and ecosystems

Address (city, state): Girona, Catalonia

Country: Spain

Please give 5 key-words showing your research / interest in Microbial Ecotoxicolgy:

  • Biofilms
  • Dissolved organic carbon
  • Rivers
  • Ecosystem functioning
  • Climate change stressors

Main kinds of contaminant(s) of interest:

  • Pesticides
  • Nanoparticles
  • Pharmaceuticals

Main kinds of microorganisms of interest:

  • Algae
  • Bacteria
  • Biofilms

Main kinds of ecosystems of interest: Streams and rivers

Do you give courses on Microbial Ecotoxicology ?: NO

Most relevant articles in the field of Microbial Ecotoxicology (max.5):

EcotoxicoMic Webinar: Florent Rossi (Université Clermont Auvergne, FRANCE)

EcotoxicoMic Webinar

Wednesday, February 6, 2019  (11:00 am, Paris Time Zone)

Webinar Registration: click here


Florent ROSSI (Université Clermont-Auvergne, France)

Leaf litter decomposition in streams subjected to global change: the role of heterotrophic microbial communities

Leaf-litter decomposition is a key mechanism in headwater streams, allowing the transfer of nutrients and energy into the entire food web. However, many streams receive a large variety of chemical compounds, including pesticides and pharmaceuticals that may exercises a high pressure on aquatic organisms, such as heterotrophic microbial communities and their organic matter decomposition activity. In this thesis, different experimental approaches were used to assess the effects of a complex and realistic chemical contamination, including nutrients and xenobiotics, on the structure, biomass and activity (decomposition ability and related extracellular enzyme activities) of microbial communities (fungi  and bacteria) colonizing Alnus litter, and their response to cope with this stress.

Firstly, a field experiment was performed on six streams, presenting different gradients of contamination over four seasons. Results showed that nutrients (especially nitrogen) were the main parameter controlling microbial activity, partially compensating the effects of xenobiotics on Alnus microbial decomposition. To go further, a microcosm experiment was performed, testing the effects of nutrients (mesotrophic versus eutrophic) and pesticides (tebuconzaole and s-metolachlor, alone or in mixture) on leaf-microbial decomposition. The interaction between high nutrients and xenobiotics led to more active microbial communities for leaf decomposition and extracellular ligninolytic activities that can be explained by changes in community structure. Moreover, a stimulation in laccase and phenol oxidase activities were observed when microbial communities were exposed to the fungicide, suggesting a role of this enzyme in detoxification mechanisms. However, the fact that such stimulation was not observed when exposed to the mixture of both pesticides (herbicide and fungicide) suggests that the interaction between these two molecules impaired the ability of microbial communities to display proper stress response. Finally, the resistance and resilience abilities of fungal communities associated with submerged leaf-litter were evaluated in vitro using a translocation experiment between an upstream (less contaminated) and downstream (more contaminated) sites of an agricultural stream. As previously observed, leaf-associated fungal communities appeared sensitive to variations in water chemical contamination, and especially in terms of extracellular laccase activity and fungal community structure. Interestingly, removing water contamination stress through the translocation of microbial communities from the more contaminated to the less contaminated channels resulted in a full recovery in terms of laccase activity and fungal community structure that can be explained by species transfer from the less contaminated to the more contaminated communities. Overall, these results highlight the importance of headwater stream fungal communities in supporting diversity for fungal communities in the more downstream sections.

In conclusion, the results of this thesis work showed that xenobiotics (including pesticides and pharmaceuticals) at environmentally relevant concentrations only have a limited effect on microbial decomposition of leaf-litter in stream ecosystems. Such low effect of the xenobiotics can be explained by the high plasticity and resilience capacity of microbial communities, coupled with their potential to produce extracellular enzymes that can be deployed for stress defense purposes.

Key words: Chemical contamination, nutrients, xenobiotics, microbial communities, leaf-litter, organic matter decomposition, laccase activity.

Thesis supervisors: Joan Artigas and Clarisse Mallet

 

EcotoxicoMic Webinar: Betty Chaumet (Irstea, Bordeaux, France)

EcotoxicoMic Webinar

Wednesday, February 6, 2019  (10:00 am, Paris Time Zone)

Webinar Registration: click here


Betty CHAUMET (Irstea Bordeaux, France)

Chaumet

Diuron transfer and distribution mechanisms in the biofilm, linked with the toxic effects associated

In 2000, the Water Framework Directive required the return of rivers to good chemical and ecological status. In particular, it has classified 45 substances as priority for this assessment (Directive 2013/39/EU), including a large proportion of pesticides. Indeed, due to their massive use, these contaminants are now found in all compartments of the environment. In addition, given its ability to integrate contamination, biofilm is considered an excellent bioindicator for water quality assessment. It is at the base of the trophic chain in aquatic environments and is composed of microorganisms (microalgae, bacteria, fungi, etc…) embedded in a matrix of extracellular polymeric substances (EPS).

This work was focused on the analysis of mechanisms of pesticide transfer and distribution in biofilms related to toxic impacts. The study was carried out using a toxicokinetic approach whereby the bioaccumulation of diuron (a photosynthesis inhibitor herbicide) was monitored in the different compartments of the biofilm. The objective was to answer the following questions: how, where and at how fast diuron is accumulated in the biofilm and what is the toxic effect associated?

To understand the bioaccumulation mechanisms, two experiments were carried out. The first was to measure the influence of the flow velocity on diuron bioaccumulation (its distribution) in the biofilm and its toxic effect. The second focused on sorption mechanisms of diuron in biofilm through exposure to a diuron concentration gradient. These two experiments were carried out in channels in a thermo-regulated room.

This work has made it possible to highlight a very rapid bioaccumulation of diuron, according to a first-order kinetics. It has also been shown that along a gradient of concentration, diuron bioaccumulation in the biofilm was not linear. This fact was established through the coupling of toxicokinetic and toxicodynamic (TK-TD) approaches. Indeed, the combination of these two approaches established that different mechanisms were taking place during accumulation, such as continuous absorption by the cells and adsorption to the EPS matrix. In addition, the TK-TD approach has allowed the development of a prediction model that links the diuron concentration in the environment to the associated toxic effect from the diuron concentration in the biofilm.