Co‐occurrence patterns of trees along macro‐climatic gradients and their potential influence on the present and future distribution of Fagus sylvatica L.

Aim During recent and future climate change, shifts in large‐scale species ranges are expected due to the hypothesized major role of climatic factors in regulating species distributions. The stress‐gradient hypothesis suggests that biotic interactions may act as major constraints on species distributions under more favourable growing conditions, while climatic constraints may dominate under unfavourable conditions. We tested this hypothesis for one focal tree species having three major competitors using broad‐scale environmental data. We evaluated the variation of species co‐occurrence patterns in climate space and estimated the influence of these patterns on the distribution of the focal species for current and projected future climates. Location Europe. Methods We used ICP Forest Level 1 data as well as climatic, topographic and edaphic variables. First, correlations between the relative abundance of European beech (Fagus sylvatica) and three major competitor species (Picea abies, Pinus sylvestris and Quercus robur) were analysed in environmental space, and then projected to geographic space. Second, a sensitivity analysis was performed using generalized additive models (GAM) to evaluate where and how much the predicted F. sylvatica distribution varied under current and future climates if potential competitor species were included or excluded. We evaluated if these areas coincide with current species co‐occurrence patterns. Results Correlation analyses supported the stress‐gradient hypothesis: towards favourable growing conditions of F. sylvatica, its abundance was strongly linked to the abundance of its competitors, while this link weakened towards unfavourable growing conditions, with stronger correlations in the south and at low elevations than in the north and at high elevations. The sensitivity analysis showed a potential spatial segregation of species with changing climate and a pronounced shift of zones where co‐occurrence patterns may play a major role. Main conclusions Our results demonstrate the importance of species co‐occurrence patterns for calibrating improved species distribution models for use in projections of climate effects. The correlation approach is able to localize European areas where inclusion of biotic predictors is effective. The climate‐induced spatial segregation of the major tree species could have ecological and economic consequences.     

Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin

doi:10.1111/j.1741‐2358.2009.00333.x
Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin Objective: The purpose of this study was to verify the effect of microwave treatment on the shear bond strength of commercial types of teeth to acrylic resin, when the glossy ridge laps were unmodified (groups 1 and 5), bur abraded (groups 2 and 6), bur grooved (groups 3 and 7) or etched by monomer (groups 4 and 8). Background: Controversial findings have shown that mechanical or chemical changes in ridge‐lap surface of the tooth increase or decrease the bond strength between tooth and acrylic resin, and the microwave disinfection may cause different changes on this bond strength. Materials and methods: Eighty specimens (n = 10) were made with the acrylic resin bonded to tooth glossy ridge lap, polymerised in water at 74°C for 9 h, and deflasked after flask cooling. Specimens of the groups 5, 6, 7 and 8 were individually immersed in 150 ml of water and submitted to microwave treatment in an oven at 650 W for 3 min. Control specimens (groups 1, 2, 3 and 4) were not microwave treated. Shear bond strength test was performed in an Instron machine with a cross‐speed of 1 mm/min. Collected data were submitted to anova and Tukey’s test (α = 0.05). Results: Microwave treatment decreased the shear bond strength values of the tooth/resin bond. In the microwaved and non‐microwaved procedures, mechanical retention improved the shear bond strength when compared with the control and monomer treatments. Conclusion: Shear bond strength of the tooth/resin bond was influenced by the microwave treatment and different commercial teeth association, and was lower for the Biotone tooth.     

Synthesis of sulfated proteoglycans throughout the cell cycle in smooth muscle cells from pig aorta

Cultured smooth muscle cells from pig aorta arrested in G0 phase by serum deprivation were stimulated to proliferate by replacing the medium with one containing 10% serum. Studies in DNA replication and proliferation of cells showed a relatively good synchrony: 90% of the cells were in G1 phase for 16 h after addition of serum; they entered S phase between 18 and 24 h, completed S phase and traversed G2 phase between 24 and 30–32 h; 75% of these cells multiplied after 30–32 h and the remainder were blocked at the end of G2 phase. The synthesis and secretion of sulfated proteoglycans were examined throughout a full cell cycle using metabolic labelling with [³⁵S]sulfate. Smooth muscle cells in G1 or G2 phase synthesized and secreted sulfated proteoglycans with a possible pause at the end of the G2 phase but at the beginning of the S phase and during mitosis the incorporation of [³⁵S]sulfate into these macromolecules stopped entirely. Structural characteristics of sulfated proteoglycans secreted into the medium during G1 phase and an entire cell cycle were investigated. The proportion of proteoglycan complexes and the relative hydrodynamic size of monomers and of constituent subunits of complexes were determined after chromatography on Sepharose CL-2B and CL-6B columns run under both associative and dissociative conditions. No significant differences were observed for the periods of the cell cycle that were studied:

1. 1. [³⁵S]Proteoglycan complexes represented at the end of G1 phase and of the cell cycle respectively 19 and 16% of the total [³⁵S]proteoglycans secreted into the medium.

2. 2. More than 90% of the subunits, obtained after dissociation of complexes, were characterized by a similar k_av after chromatography on Sepharose CL-2B columns eluted under dissociative conditions (k_av 0.68 at the end of G1 phase and 0.65 at the end of full cell cycle).

3. 3. About 95% of monomers synthesized at the two stages of the cell cycle were eluted at k_av 0.25 after chromatography on Sepharose CL-6B column run under associative conditions and were characterized by a similar glycosaminoglycan distribution. These results suggest that smooth muscle cells in culture liberate similar populations of proteoglycans into the medium during the G1 and G2 phases.

     

Etude des premiers stades de développement de la Coccidie Coelotropha durchoni

Summary This study considers the earlier growth stages of Coccidium Coelotropha durchoni in its host, Nereis diversicolor. Before evolving into free trophozoites and gamontes in coeliac fluid, the parasites remain in muscular and coeliac cells in microscopic intracellular form. Electron microscope reveals that these stages show an intermediary fine structure between that of a sporozoite — from which they keep some typical characteristics such as the conoid, the fibers and the involuted tubuli — and that of the future free trophozoites. The wall consisting in two clear membrans is provided with one or several micropores. The classical cytoplasmic organites clearly stand out: dictyosomes show constant relationship with ergastoplasm, the mitochondria contain short inner tubuli. Besides the paraglycogen granules and lipoid vacuoles, at least three types of vacuoles may be observed. Peculiar topographic relationship connects mitochondria and paraglycogen granules probably in formation. In the nucleus with classical membrane and heterogeneous structure, a rather voluminous nucleolus may be seen.     

Diversity and evolution of leaflet anatomical characters in the Pterocarpus clade (Fabaceae: Papilionoideae)

Journal of Plant Research - The Pterocarpus clade includes 23 genera previously attributed to different Fabaceae tribes. The recent rearrangements of many genera in the clade do not recognize...     

Catecholamine and MHPG plasma levels,platelet MAO activity,and3H-imipramine binding in heroin and cocaine addicts

This work evaluated in a population of heroin and heroin plus cocaine human addicts:

1. Norepinephrine (NE), epinephrine (Epi), and 3-methoxy-4-hydroxyphenylglycol (MHPG) (the principal metabolite of brain NE) plasma levels;
2. Monoamine oxidase (MAO) activity; and
3. ³H-imipramine specific binding to the amine carrier in platelets.

NE plasma levels were significantly lower in the short-term heroin user groups (1–3 and 4–6 yr), a finding not observed in both the long-term heroin user (>6 yr) and heroin plus cocaine user (>6 yr) groups. Epi levels changed in a similar manner, except that a significant increase was noted in heroin plus cocaine abusers. Conversely, dopamine and MHPG plasma levels increased with the duration of heroin use, and even more with cocaine abuse. Platelet MAO activity increased in all groups. Specific³H-imipramine binding sites showed an increase after 3 yr of heroin abuse and in all heroin plus cocaine addicts. In conclusion, short-term use of heroin decreases NE or Epi release, but with prolonged use, a slow adpatation occurs. In contrast, cocaine inhibits the neuronal Epi uptake, even in a situation of long duration of abuse. Probably the amine levels additionally regulate the amine carrier, resulting in changes that show a different pattern from major depression. These drugs of abuse may also influence directly or indirectly related enzymatic systems.     

Chemical composition and ultrastructure of cellular and extracellular Moraxella glucidolytica lipopolysaccharides

A cellular (LPS I) and extracellular (LPS II) lipopolysaccharide were isolated from Moraxella glucidolytica cells grown on ethanol and from the culture fluid, respectively. Both LPS were toxic when injected to mice and chick embryos. These LPS contained glucose, galactose, glucosamine, galactosamine, 2-keto-3-deoxyoctonate and lipids. By permethylation studies, glucose was found to be linked (16) and (13) in LPS I and only (16) in LPS II. Galactose was the terminal non-reducing sugar. Branching occurred at positions 3 and 4 of galactose residues. LPS I was rich in - and -hydroxylauric and -hydroxymyristic acids and LPS II contained mainly stearic and -hydroxymyristic acids. LPS I was detoxified by mild acid and alkaline treatments. It was also dissociated by sodium deoxycholate and chromatographed on Sephadex G-75. The main fraction was reassociated by removing the surfactant by dialysis. The morphology of LPS I and LPS II was examined by electron microscopy. LPS I (original and reassociated fractions) consisted exclusively of ribbons while LPS II contained ribbons and vesicles.Non-Standard Abbreviations KDO 2-Keto-3-deoxyoctonic acids - LPS Lipopolysaccharide - NaD Sodium deoxycholate     

Notes on the vegetation of Amazonia II. The dispersal of plants in Amazonian white sand campinas: The campinas as functional islands

The dispersal mechanisms of 37 species of plants which occur on Amazonian white sand campinas were studied. 75.67 percent of the species have the potential for long distance diaspore dispersal, including 59.46 percent which are bird-dispersed. This dispersal disharmony towards long-distance dispersal and especially towards ornithochory is characteristic of islands in general. The campinas of the lower Rio Negro region of Amazonia may be treated biogeographically as islands surrounded by large areas of tropical rain forest. A total of eight dispersal types was observed and details of these mechanisms are presented. The type of germination of many of the species studied is reported for the first time.