@article {1754, title = { Bacteria alone establish the chemical basis of the wood-fall chemosynthetic ecosystem in the deep-sea }, journal = { ISME JOURNAL }, volume = {12}, year = {2018}, pages = {367-379}, abstract = {

Wood-fall ecosystems host chemosynthetic bacteria that use hydrogen sulfide as an electron donor. The production of hydrogen sulfide from decaying wood in the deep-sea has long been suspected to rely on the activity of wood-boring bivalves, Xylophaga spp. However, recent mesocosm experiments have shown hydrogen sulfide production in the absence of wood borers. Here, we combined in situ chemical measurements, amplicon sequencing and metagenomics to test whether the presence of Xylophaga spp.-affected hydrogen sulfide production and wood microbial community assemblages. During a short-term experiment conducted in a deep-sea canyon, we found that wood-fall microbial communities could produce hydrogen sulfide in the absence of Xylophaga spp. The presence of wood borers had a strong impact on the microbial community composition on the wood surface but not in the wood centre, where communities were observed to be homogeneous among different samples. When wood borers were excluded, the wood centre community did not have the genetic potential to degrade cellulose or hemicellulose but could use shorter carbohydrates such as sucrose. We conclude that wood centre communities produce fermentation products that can be used by the sulfate-reducing bacteria detected near the wood surface. We thus demonstrate that microorganisms alone could establish the chemical basis essential for the recruitment of chemolithotrophic organisms in deep-sea wood falls.

}, author = {D. KALENITCHENKO and N. LE-BRIS and L. DADAGLIO and E. PERU and A. BESSERER and P.E. GALAND} } @article {1668, title = { Predicting the beech wood decay and strength loss in-ground }, journal = { INTERNATIONAL BIODETERIORATION \& BIODEGRADATION }, volume = {123}, year = {2017}, pages = {96-105}, abstract = {

In the context of reduction of CO2 emissions and costs in the construction industry, substitution of concrete by wood for foundation piles seems to be a promising alternative. To promote the use of local wood in pile foundation, diagnostic and prediction methodology of wood decay in soil need to be improved. Outdoor mesocosm decay experiments were performed to evaluate the potential use of beech wood as foundation piles. The stochastic occurrence of soil fungal inoculum in contact with mini-stakes and water gradient in wood explained the observed patchy wood decay pattern. Various patterns of wood rotting fungi were identified. The correlation between measured strength loss and mass loss was weak. Multivariate analyses using biochemical and physico-chemical data as inputs allowed section categorizations and prediction of wood strength. Accuracy of the prediction was validated by experimental measurement of the compression parallel to the grain (f(c),(o)).The categorization of unknown sections was computed by PLS-DA and provided clues inferring their service life. The described procedure has the potential to be transferred to on-site measurements to predict the f(c,o) of wood foundation pile or any potentially damaged timber structure.

}, author = {Q. KLEINDIENST and A. BESSERER and M.L. ANTOINE and C. PERRIN and J.F. BOCQUET and L. BL{\'E}RON} } @article {1638, title = { Evaluating mold growth in tannin-resin and flax fiber biocomposites }, journal = { INDUSTRIAL CROPS AND PRODUCTS }, volume = {83}, year = {2016}, pages = {438-443}, abstract = {

Flax fiber is an industrially available, renewable product with attractive technical properties for the composite industry such as density, mechanical strength and sound/heat insulation. Applications are developing quickly for biocomposites based on these fibers. However, unlike plastics, there is no standard used to assess its degree of contamination by microorganisms. Thus, the aims of this work were to detect and quantify molds in samples of nonwoven fibrous materials from industry and high resin content natural matrix-natural fiber biocomposites. In a first attempt, we tried to evaluate the fungal development on the nonwoven materials as defined in the ISO 846 standard. Despite the materials having been inoculated with molds, no fungal mycelium could be detected by this way. To validate this observation, we developed a qualitative approach based on the specific aniline blue method to stain the mycelium present in the material. This allowed us to detect the mold occurrence in the material and to evaluate the colonization extent on the nonwoven fibrous materials incubated under different conditions. The biocide efficiency of a boric acid pretreatment of flax fibers used in the manufacturing process of nonwoven fibrous materials and high resin content natural matrix-natural fiber biocomposites was determined by grading the mold development using the microscope-based method that we developed. The results showed clearly that in optimal mold growth conditions, (Aw \> 0.6, 26 degrees C) the colonization of the material was hampered by the boric acid pretreatment of the flax fibers. To get semi-quantitative data of the colonization extent, we used a molecular method. DNA was extracted from the different materials and the ribosomal region of the fungal DNA was amplified by PCR allowing the detection and the quantification of fungal colonization in the biosourced material. Results confirmed the microscopy-based method. Work is currently in progress to determine risk classes of mold colonization in wood-derived and fibrous-based composite materials.

}, url = {https://hal.univ-lorraine.fr/hal-01598422}, author = {C. SEGOVIA and A. SAUGET and A. BESSERER and R. KUENY and A. PIZZI} } @article {1609, title = { Morphological Characterization and Quantification of the Mycelial Growth of the Brown-Rot Fungus Postia placenta for Modeling Purposes }, journal = { PLOS ONE }, volume = {11}, year = {2016}, abstract = {

Continuous observation was performed using confocal laser scanning microscopy to visualize the three-dimensional microscopic growth of the brown-rot fungus, Postia placenta, for seventeen days. The morphological characterization of Postia placenta was quantitatively determined, including the tip extension rate, branch angle and branching length, (hyphal length between two adjacent branch sites). A voxel method has been developed to measure the growth of the biomass. Additionally, the tip extension rate distribution, the branch angle distribution and the branching length distribution, which quantified the hyphal growth characteristics, were evaluated. Statistical analysis revealed that the extension rate of tips was randomly distributed in space. The branch angle distribution did not change with the development of the colony, however, the branching length distribution did vary with the development of the colony. The experimental data will be incorporated into a lattice-based model simulating the growth of Postia placenta.

}, url = {https://hal.univ-lorraine.fr/LERMAB-UL/hal-01365606}, author = {H. DU and P. LV and M. AYOUZ and A. BESSERER and P. PERRE} }