Abstract A sequence coding for a peroxiredoxin (Prx) was isolated from xylem/phloem cDNA library Populus trichocarpaand subsequently inserted into an expression plasmid yielding the construction pET-Prx. The recombinant protein produced inEscherichia coli cells and purified to homogeneity with high yield. poplar Prx is composed of 162 residues, property that makes it shortest plant so far. It shown monomeric possesses two conserved cysteines (Cys). degrades hydrogen peroxide alkyl...

The authors have studied the ultrastructural organization of two synthetic mycorrhizas between Helianthemum salicifolium (L.) Mill. (Cistaceae) and Terfezia claveryi Chat. or leptoderma Tul. (Ascomycetes, Terfeziaceae). With an endomycorrhiza is formed with many hyphae hugging inside surface cell wall. cytoplasmic volume mycorrhizal cells not significantly increased. ectomycorrhiza without a sheath formed, but there typical Hartig net. These types mycorrhiza constitute examples biotrophism.

Cell separation is dependent on cell wall hydrolases that cleave the peptidoglycan shared between daughter cells. In Streptococcus thermophilus, this step performed by Cse protein whose depletion resulted in formation of extremely long chains Cse, a natural chimeric enzyme created domain shuffling, carries at least two important domains for its activity: LysM expected to be responsible wall-binding and CHAP predicted contain active centre. Accordingly, localization S. thermophilus surface...

Abstract Ozone induces stomatal sluggishness, which impacts photosynthesis and transpiration. Stomatal responses to variation of environmental parameters are slowed reduced by ozone may be linked difference sensitivity. Here we determine the effects on conductance each leaf surface. Potential causes this sluggish movement, such as ultrastructural or ionic fluxes modification, were studied independently both surfaces three Euramerican poplar genotypes differing in sensitivity behaviour. The...

The invasion of alien macrophytes in aquatic ecosystems has caused serious ecological and economic impacts. Their introduction often leads to competition with natives already established invasive species. Competition among species is assumed be greater than native species, especially for plants similar growth form position the water column. Many freshwater bodies are eutrophicated due high phosphorus inputs, which have led a competitive advantage macrophytes. A decrease column load might...

Abstract Gravity is a permanent environmental signal guiding plant growth and development. sensing in plants starts with the displacement of starch-filled plastids called statoliths, ultimately leading to auxin redistribution organ curvature. While involvement gravity several actors such as calcium known, effect statolith on changes remains enigmatic. Microgravity unique condition offering opportunity decipher this link. In study, roots Brassica napus were grown aboard International Space...

Isocitrate dehydrogenase (IDH) activities were measured in mitochondria isolated from aerial parts of 21‐day‐old spruce ( Picea abies L. Karst.) seedlings. Mitochondria purified by two methods, involving continuous and discontinuous Percoll gradients. Whatever the method purification, mitochondrial outer membrane was about 69% intact, contained very low cytosolic, chloroplastic peroxisomal contaminations. Nevertheless, as judged recovery fumarase activity, purification on a 28% gradient gave...

Introduction of invasive macrophytes often leads to competition with native species or already established species. Competition between in multiple-invaded systems is expected be particularly high, especially when they share growth form and position the water column. We performed indoor experiments free-floating Lemna minuta Landoltia punctata monocultures mixtures under a phosphorus gradient concurring hypereutrophic, eutrophic, mesotrophic, oligotrophic conditions. Our results showed that...

RésuméLa localisation ultrastructurale des activités phosphatasiques acides est recherchée dans deux associations ectomycorhiziennes à Basidiomycètes, obtenues en conditions contrôlées.Dans le réseau de Hartig, les enzymatiques sont révélées sur plasmalemme cellules corticales vivantes et hyphes du champignon. Une faible activité diffuse parfois observée ciment interhyphal.Dans manteau, ces mises évidence long interhyphal. Les situées la surface manteau ou libres milieu montrent une forte...

In nonmycorrhizal roots, the plastids of cortical cells developed either into leucoplasts (Plectranîhus australis) or amyloplasts (Prunus avium and Pirus malus). infected with endophyte vesicular-arbuscular mycorrhizas, in all three species studied, were very long secretory a well-developed stromatic tubular net. woody Rosaceae, absence starch is thought to result from disturbance carbon metabolism caused by endophyte. Differentiation net may be expression defense reaction.

Summary The interfacial organization of ectendomycorrhizas monotropa was studied with different cytochemical methods. ectomycorrhizal part comprises a thick sheath and reduced Hartig net. extractions by DMSO or EDTA show that the cement has an heterogenous structure. middle part, between hyphae, contains fibrillar poly—saccharidic material which is insensitive to chemical extractions. This associated proteins. chitin, characteristic fungal wall, not present in cement. endomycorrhizal...

Toutes les associations mycorhiziennes à vesicules et arbuscules étudiées par auteurs présentent une organisation ultrastructurale identique, mais dans un cas, ils ont observé des hyphes intercellulaires organisés en pseudoréseau de Hartig.Les cellules l'hôte infectées l'endophyte sont caractérisées augmentation très importante du volume cytoplasmique le développement d'une grande surface plasmalemmique autour l'arbuscule. Ce plasmalemme néoformé présente propriétés plasmalemmiques typiques,...

Summary The authors have observed three different types of inclusions in hyphae the endophyte: dense vacuolar granules, less and often diffuse granules included small cytoplasmic vesicles. These were studied by cytochemical techniques energy electron loss spectroscopy. Dense correspond to polyphosphate already described many authors. They contain phosphorus calcium associated with a proteic fraction. Cytoplasmic are protein-rich without calcium. suggest that precursors granules. contained...

Les auters étudient l'organisation ultrastructurale et la localisation de diverses activités enzymatiques (ATPases, phosphatases neutres, acides) dans le champignon symbiote isolé associé.Les structures pariétales présentent des modifications remarquables sont caractérisées par une simplification structure un amincissement important associé.De même, les ATPasiques phosphatasiques neutres différente ou associé. Dans ce dernier, leur sur plasmalemme est interprété comme étant l'indication...