[Factors controlling soil macrofauna spatial pattern in a pure beech and a mixed beech-hornbeam forest]. / Facteurs contrôlant la variabilité spatiale de la macrofaune du sol dans une hêtraie pure et une hêtraie-charmaie.

The soil macrofauna of a pure beech (PS) and a mixed beech-hornbeam (MS) stand was recorded using a sample design spatially explicit at stand level. Humic epipedon morphological and chemical properties, relative irradiance, soil bulk density, and the specific composition of the litter in MS were also investigated. The taxonomic diversity is nearly similar on both sites, but the average by sample is greater under PS. The main factors controlling soil macrofauna spatial variability were: litter quality under MS and humus form activity under PS. These results suggest a distal control (i.e. external to humic epipedon) of macrofauna spatial variability when the litter quality is variable and a proximal control (i.e. internal to humic epipedon) when it is uniform at the spatial scale of the study.

Protein N-glycosylation is similar in the moss Physcomitrella patens and in higher plants.

We have investigated the structure of glycans N-linked to the proteins of the moss Physcomitrella patens. The structural elucidation was carried out by western blotting using antibodies specific for N-glycan epitopes and by analysis of N-linked glycans enzymatically released from a total protein extract by combination of MALDI-TOF and MALDI-PSD mass spectrometry analysis. Nineteen N-linked oligosaccharides were characterised ranging from high-mannose-type and truncated paucimannosidic-type to complex-type N-glycans harbouring core-xylose, core-alpha(1,3)-fucose and Lewis(a), as previously described for proteins from higher plants. This demonstrates that the processing of N-linked glycans, as well as the specificity of glycosidases and glycosyltransferases involved in this processing, are highly conserved between P. patens and higher plants. As a consequence, P. patens appears to be a new promising model organism for the investigation of the biological significance of protein N-glycosylation in the plant kingdom, taking advantage of the potential for gene targeting in this moss.