Improved solid-phase extraction procedure in the analysis of paralytic shellfish poisoning toxins by liquid chromatography with fluorescence detection

The analysis of shellfish extracts for the determination of paralytic shellfish poisoning (PSP) toxins by liquid chromatography with fluorescence detection repeatedly showed the presence of a compound suspected to interfere with gonyautoxin 4. The first aim of this study was to confirm by liquid chromatography coupled to tandem mass spectrometry that this compound was not gonyautoxin 4. The second part of this work was to improve a nonvolumetric C(18) solid-phase extraction (SPE) procedure to evaluate the removal of the interference associated with the recovery of PSP toxins. The cleanup procedure was modified into a volumetric SPE procedure and proved to efficiently and totally remove the interference while recovering from 78 to 85% of the PSP toxins available as commercial standards (saxitoxin, neosaxitoxin, gonyautoxins 1-4) and considered as major PSP toxins in human intoxication, with 85% recovery for gonyautoxin 4. The efficiency of this cleanup procedure was checked on shellfish extracts containing this interference and originating from France and Turkey.     

The efficacy of small-scale conservation efforts, as assessed on Australian golf courses

Habitat remnants on urban green-space areas (i.e. parks, gardens and golf courses) sometimes provide refuge to urban-avoiding wildlife, leading some to suggest these areas may play a role in wildlife conservation if they are appropriately designed and managed. The high densities observed on some green-space areas may however be attributed to external influences. Localised efforts to enhance the habitat value of urban green-space areas may therefore have little more than a cosmetic effect. This study investigated environmental factors influencing bird, reptile, mammal and amphibian diversity on Australian golf courses to assess the efficacy of small-scale conservation efforts. Abundance and species richness did not simply reflect local habitat qualities but were instead, partly determined by the nature of the surrounding landscape (i.e. the area of adjacent built land, native vegetation and the number of connecting streams). Vertebrate abundance and species richness were however, also associated with on-site habitat characteristics, increasing with the area of native vegetation (all vertebrates), foliage height diversity and native grass cover (birds), tree density, native grass cover and the number of hollows (mammals), woody debris, patch width and canopy cover (reptiles), waterbody heterogeneity and aquatic vegetation complexity (frogs). Localised conservation efforts on small land types can benefit urban-avoiding wildlife. Urban green-space areas can provide refuge to urban-avoiding vertebrates provided combined efforts are made at patch (management), local (design) and landscape (planning) scales.     

Paired comparison of water, energy and carbon exchanges over two young maritime pine stands (Pinus pinaster Ait.): effects of thinning and weeding in the early stage of tree growth

The effects of management practices on energy, water and carbon exchanges were investigated in a young pine plantation in south-west France. In 2009-10, carbon dioxide (CO(2)), H(2)O and heat fluxes were monitored using the eddy covariance and sap flow techniques in a control plot (C) with a developed gorse layer, and an adjacent plot that was mechanically weeded and thinned (W). Despite large differences in the total leaf area index and canopy structure, the annual net radiation absorbed was only 4% lower in plot W. We showed that higher albedo in this plot was offset by lower emitted long-wave radiation. Annual evapotranspiration (ET) from plot W was 15% lower, due to lower rainfall interception and transpiration by the tree canopy, partly counterbalanced by the larger evaporation from both soil and regrowing weedy vegetation. The drainage belowground from plot W was larger by 113 mm annually. The seasonal variability of ET was driven by the dynamics of the soil and weed layers, which was more severely affected by drought in plot C. Conversely, the temporal changes in pine transpiration and stem diameter growth were synchronous between sites despite higher soil water content in the weeded plot. At the annual scale, both plots were carbon sinks, but thinning and weeding reduced the carbon uptake by 73%: annual carbon uptake was 243 and 65 g C m(-2) on plots C and W, respectively. Summer drought dramatically impacted the net ecosystem exchange: plot C became a carbon source as the gross primary production (GPP) severely decreased. However, plot W remained a carbon sink during drought, as a result of decreases in both GPP and ecosystem respiration (R(E)). In winter, both plots were carbon sources, plots C and W emitting 67.5 and 32.4 g C m(-2), respectively. Overall, this study highlighted the significant contribution of the gorse layer to mass and energy exchange in young pine plantations.     

Heritability and predicted selection response of yield components and fibre properties in an inter-specific derived RIL population of cotton

Exploiting genetic variation through inter-specific breeding has improved cotton yield, fibre properties and adaptability. The objectives of this study were to examine heritability and predicted selection response of yield components and fibre properties in a recombinant inbred line (RIL) population from an inter-specific cross between Gossypium hirsutum (Gh) variety Guazuncho 2, and G. barbadense (Gb) line VH8-4602. A population of 93 and 82 RILs was tested in two seasons, with two parents and local controls, Sicot 75 (Gh) and Sipima 280 (Gb) in field experiments. Seed cotton samples hand harvested before and after defoliation were used to measure lint percent, boll weight, 100 seed weight and the lint to measure fibre length, uniformity, short fibre index (SFI), elongation, strength, micronaire, maturity ratio (MR), percent of maturity (PM) and fineness. There was large phenotypic variation for individual traits and transgressive segregation occurred in lint percent, lint weight/seed, fibre no./seed, uniformity, SFI, elongation, MR and PM. Narrow sense heritabilities were moderate for yield components (34.3–41.2%) and for key fibre properties, length, strength, micronaire and fineness (38.3–42.1%), which led to a predicted selection response of 6.7–24.0% for yield components and 3.9–10.9% for key fibre properties under a selection intensity of 10%. Favourable associations were found between key fibre properties, but an adverse association between lint percent and each of these fibre properties. Only five RILs were identified with desirable combinations. The results demonstrated the value of exploiting inter-specific variation to develop cotton germplasm and how breeding strategies can be improved.     

Identification of Brucella abortus, B. canis, B. melitensis, and B. suis by carbon substrate assimilation tests

By using the results of seven carbon substrate assimilation tests from the Biotype 100 system (bioMérieux, Marcy-l’Etoile, France), we correctly identified 79 (85.9%) of 92 Brucella strains tested. The specificity of the method varied from 97.4 to 100% depending on the species. Although a biological safety cabinet must be used, this method represents an easy and fast alternative for the identification of Brucella species.     

Vegetative propagation of Vitellaria paradoxa by grafting

Vitellaria paradoxa or karité is a wild fruit-bearing tree species of sudano-sahelian parklands that plays an important socio-economic role in Sub-Saharan Africa due to the commercial and domestic value of the fruits. Principal constraints of karité fruit production are: long juvenile phase, slow growth, genetic variability and lack of knowledge regarding the cultivation of the species. To address these constraints and to enhance productivity and quality, five methods of grafting (side cleft, top cleft, tongue, chip budding and side veneer), two methods of pre-treatment of scions and rootstocks (washing with 10% sodium hypochlorite to wash off latex and sterilise and a control without washing), and two methods of protection of grafts against desiccation (covering with white plastic sheet and aluminium foil) were tested. The results showed decreasing success of survival of grafts 16 weeks after grafting for the five grafting techniques: side cleft (86.1%), tongue (80.9%), top cleft (78.1%), chip budding (38.1%) and side veneer (20.7%) grafting methods. The results also showed May to be the optimum time for grafting, with high rates of shoot growth and survival of grafts. The average annual growth rate of grafts was 12.6 cm. The pre-treatment of scions with 10% sodium hypochlorite, however, had no significant effect on survival of scions. There was also no significant difference in survival of scions between the two methods of protection of grafts against desiccation (aluminium foil and plastic sheet). Two grafts produced fruits two years after grafting using side veneer grafting.This revised version was published online in November 2005 with corrections to the Cover Date.     

Abundance and distribution of<Emphasis Type="Italic"> Xylosandrus germanus</Emphasis> (Blandford 1894) (Coleoptera,Scolytidae) in Belgium: new observations and an attempt to outline its range

In Belgium, the current distribution and abundance of Xylosandrus germanus (Coleoptera, Scolytidae), a relatively new species to the Belgian fauna, is poorly known. Therefore, data on the range and population levels of this ambrosia beetle, on a regional and local scale respectively, are presented. Based on those results, the beetles range is discussed. Among the analysed biotic and abiotic factors that could influence the species settlement and population levels, climatic ones, and temperature in particular, seem to exert a crucial influence.     

Climate warming and the rainforest birds of the Australian Wet Tropics: Using abundance data as a sensitive predictor of change in total population size

Global average surface temperatures have increased rapidly over the last 100 years and there is accumulating evidence that climate change is already causing shifts in species’ distributions. We use extensive abundance data and expected range shifts across altitudinal gradients to predict changes in total population size of rainforest birds of Australian tropical rainforests in response to climate warming. According to our most conservative model scenario, 74% of rainforest birds of north-eastern Australia are predicted to become threatened (including 26 critically endangered species) as a result of projected mid-range warming expected within the next 100 years. Extinction risk varies according to where along the altitudinal gradient a species is currently most abundant. Upland birds are most affected and are likely to be immediately threatened by even small increases in temperature. In contrast, there is a capacity for the population size of lowland species to increase, at least in the short term. We conclude that abundance data collected across climatic gradients will be fundamental to gaining an understanding of population size change associated with climate warming.     

Within-stand and seasonal variations of specific leaf area in a clonal Eucalyptus plantation in the Republic of Congo

Specific leaf area (SLA; m²_leaf kg^?1_leaf) is a key ecophysiological parameter influencing leaf physiology, photosynthesis, and whole plant carbon gain. Both individual tree-based models and other forest process-based models are generally highly sensitive to this parameter, but information on its temporal or within-stand variability is still scarce. In a 2–4-year-old Eucalyptus plantation in Congo, prone to seasonal drought, the within-stand and seasonal variability in SLA were investigated by means of destructive sampling carried out at 2-month intervals, over a 2-year period. Within-crown vertical gradients of SLA were small. Highly significant relationships were found between tree-average SLA (SLA_t) and tree size (tree height, H_t, or diameter at breast height, DBH): SLA_t ranged from about 9 m² kg^?1 for dominant trees to about 14–15 m² kg^?1 for the smallest trees. The decrease in SLA_t with increasing tree size was accurately predicted from DBH using power functions. Stand-average SLA varied by about 20% during the year, with lowest values at the end of the 5-month dry season, and highest values about 2–3 months after the onset of the wet season. Variability in leaf water status according to tree size and season is discussed as a possible determinant of both the within-stand and seasonal variations in SLA.