Spatial and temporal dynamics in the Phialocephala fortinii s.l. – Acephala applanata species complex (PAC)

Background and aims Dark septate endophytes of the Phialocephala fortinii s.l. – Acephala applanata species complex (PAC) are abundant root colonizers of woody plants in boreal and temperate forest ecosystems where they form complex communities. Community structure was spatially stable for 3 years in a previous experiment, suggesting PAC’s inability to disperse or mutual inhibition of neighboring PAC genotypes. The aim of this study was to test whether changes in PAC community structure occur at all. Methods The community structure originally determined in 2004 was reassessed in 2014 in a Norway-spruce plantation using microsatellite genotyping. Results Most isolates belonged to Phialocephala turicensis, P. letzii, P. europaea, and P. helvetica in both years. P. uotilensis and Acephala applanata were rare. PAC species were the same at only two grid points in both years. P. europaea was more frequent than P. turicensis in 2004 whereas the situation was opposite in 2014. Only four of the 22 genotypes in 2004 were found in 2014. Interestingly, none of the genotypes was detected at the same grid points in both years. Extended sampling in 2014 led to a significantly higher number of grid points testing positive for the presence of P. turicensis and P. helvetica. Conclusions More than 3 years are required to detect shifts in PAC community structures. The observed shifts suggest that PAC are able to disperse in soil or via root networks, though very slowly.ISSN:0032-079XISSN:1573-503

Molécules migrantes de l'emballage et perturbation endocrinienne

DIJON-BU Sciences Economie (212312102) / SudocSudocFranceF

Ecological factors influencing norway spruce regeneration on nurse logs in a subalpine virgin forest

Regeneration of Picea abies in high-elevation mountain forests often depends on the presence of coarse woody debris (CWD), as logs provide sites with more favorable conditions for spruce regeneration compared to the forest floor. However, there is little quantitative knowledge on the factors that are conducive to or hindering spruce establishment on CWD. We examined spruce regeneration on CWD by sampling 303 plots (50 cm × 50 cm each) on 56 downed logs in a virgin forest in the Swiss Alps. Variables describing microsite conditions were measured, and fungi were isolated from wood samples. To investigate the relationship between the ecological factors and establishment success, two models were fitted with seedling and sapling density as response variables, respectively. Besides log diameter, the models identified different ecological factors as significant for seedling and sapling establishment, i.e., regeneration depends on different factors in different development stages. Seedling density depended on the type of rot, log inclination, and decay stage. Sapling density depended mainly on light availability, cover by bark and moss, the time of tree fall, and the distance between the log surface and the forest floor. A total of 22 polypore fungi were isolated from the wood samples, four of them being threatened species. White- and brown-rot fungi were found in all decay stages. The visual assessment of the type of rot in the field corresponded in only 15% of cases to the type of rot caused by the isolated fungi; hence caution is needed when making field assessments of rot types.ISSN:1999-490

Root contact dominates vegetative transmission of the Phialocephala fortinii s.l. – Acephala applanata species complex (PAC)

The Phialocephala fortinii s.l. – Acephala applanata species complex (PAC) is composed of closely related endophytic ascomycetes colonizing roots of coniferous trees. Their means of dispersal and teleomorphic form are still unknown. Accordingly, we focused on vegetative mycelial spread of PAC i) via root contacts from PAC-inoculated to PAC-free saplings, ii) through semi-sterile soil from PAC-colonized to PAC-free saplings (without contact) and iii) through semi-sterile soil from PAC-colonized substrate to PAC-free saplings (without contact). Five PAC strains were selected for the experiment. All three modes of PAC transmission found support and were confirmed by metabarcoding. However, transmission via root contact was found to be the most successful. Growth of PAC through soil was also observed whereby transmission from PAC-colonized substrate to PAC-free saplings was more frequent than transmission from PAC-colonized to PAC-free saplings. The transmission rates depended on the PAC strain. Overall, we found support for vegetative transmission of PAC via root contact and active mycelial spread through semi-sterile soil.ISSN:1754-5048ISSN:1878-008

Effect of in utero exposure to di-(2-ethylhexyl)phthalate: Distribution in the rat fetus and testosterone production by rat fetal testis in culture

International audienceDEHP is known to cause reproductive toxicity in rats, particularly during the neonatal period. Pregnant and brood rats were treated by gavage with 750 mg/kg b.w./day DEHP starting on GD14 within PND4. Two hours after 14C-DEHP administration on GD15, GD18, GD21 and PND4, the radioactivity content was measured in the dams blood and in the liver, gonads and carcass of the offspring. The radioactivity concentration recovered in the fetuses was one or two order of magnitude lower than the concentration found in the dam plasma. A low proportion of radioactivity was present in fetal gonads, ca. 2%, 5% and 3.6% on GD18, GD21 and PND4, respectively. The effect on testosterone production of DEHP and its metabolites (MEHP, metabolites VI and IX) was assessed in fetal testis cultures using a dose-range which included the maximal exposure observed in vivo. None of the compounds affected testosterone production. Thus, DEHP and/or its metabolites appear to cross the placental barrier, reach the fetal gonads. In vitro, neither DEHP nor its main metabolites decreased the testosterone production

Feathers and lime

This project forms part of the ongoing research output of The Caseroom Press. It brings together the concept and format of the Artists Book with the commercial viability and profile of a published edition. The author, Ken Cockburn, is an internationally recognised poet and writer. His first collection of poems was shortlisted for a Saltire award; He established and ran, along with Alec Finlay, pocketbooks which was an award winning series of books of poetry and visual art. Along with his work for the Caseroom Press he was until recently a director of Platform Projects, one of which won the Scottish Design Award 2006. We would aim to add this book to the already established reputation we have with collections such as the Winchester School of Art Artists Book Archive

Investigating Host Preference of Root Endophytes of Three European Tree Species, with a Focus on Members of the Phialocephala fortinii—Acephala applanata Species Complex (PAC)

Host preference of root endophytes of the three European tree species of Norway spruce (Picea abies), common ash (Fraxinus excelsior), and sycamore maple (Acer pseudoplatanus) were investigated in two forest stands near Zurich, Switzerland. The focus was placed on members of the Phialocephala fortinii s.l. (sensu lato)—Acephala applanata species complex (PAC), as well as other dark septate endopyhtes (DSE). PAC species were identified based on 13 microsatellite loci. Eleven PAC species were found, with Phialocephala helvetica, P. europaea being the most frequent. All but cryptic species 12 (CSP12) preferred Norway spruce as a host. Though very rare in general, CSP12 was most frequently isolated from maple roots. Regarding the abundant PAC species, P. helvetica and P. europaea, the preference of spruce as a host was least pronounced in P. europaea, as it was also often isolated from ash and maple. It is the first record of PAC found on common ash (Fraxinus excelsior). Cadophora orchidicola, a close relative of PAC, has frequently been isolated from ash. Various species of the Nectriaceae (Cylindrocarpon spp.) have often been isolated, particularly from maple roots. By comparison, Pezicula spp. (Cryptosporiopsis spp.) was found to be abundant on all three hosts. Phomopsis phaseoli exhibits a clear preference for spruce

Ecological Factors Influencing Norway Spruce Regeneration on Nurse Logs in a Subalpine Virgin Forest

Regeneration of Picea abies in high-elevation mountain forests often depends on the presence of coarse woody debris (CWD), as logs provide sites with more favorable conditions for spruce regeneration compared to the forest floor. However, there is little quantitative knowledge on the factors that are conducive to or hindering spruce establishment on CWD. We examined spruce regeneration on CWD by sampling 303 plots (50 cm × 50 cm each) on 56 downed logs in a virgin forest in the Swiss Alps. Variables describing microsite conditions were measured, and fungi were isolated from wood samples. To investigate the relationship between the ecological factors and establishment success, two models were fitted with seedling and sapling density as response variables, respectively. Besides log diameter, the models identified different ecological factors as significant for seedling and sapling establishment, i.e., regeneration depends on different factors in different development stages. Seedling density depended on the type of rot, log inclination, and decay stage. Sapling density depended mainly on light availability, cover by bark and moss, the time of tree fall, and the distance between the log surface and the forest floor. A total of 22 polypore fungi were isolated from the wood samples, four of them being threatened species. White- and brown-rot fungi were found in all decay stages. The visual assessment of the type of rot in the field corresponded in only 15% of cases to the type of rot caused by the isolated fungi; hence caution is needed when making field assessments of rot types

Estrogenic effects of food wrap packaging xenoestrogens and flavonoids in female Wistar rats : a comparative study

International audienceThe objective of this study was to compare the estrogenicity of xenoestrogens found in food wrap packaging and phytoestrogen flavonoids. Uterotrophic and vaginal cornification assays were performed on immature and ovariectomized rats. Genistein, bisphenol F, and octylphenol were identified as estrogenic only in immature rats. Using vaginal cornification as a more specific estrogenic parameter, all tested compounds except tangeretin were active in immature rats. While apigenin and kaempferol appeared to have low estrogenic activity, they potentialized the uterotrophic effect of 17β-estradiol in immature rats. These data showed that (i) phytoestrogens like genistein can be as potent or even more estrogenic than compounds found in food wrap packaging, (ii) immature rats appear to be a more sensitive in vivo model than ovariectomized rats in term of estrogenicity, (iii) the vaginal cornification assay could be a sensitive and useful test to detect weak estrogenic compounds to which humans can be exposed via food