Characteristics of the aeropollen dynamics at several localities in Spain

In the Iberian Peninsula and Balearic Islands there are several bioclimatic regions which result in many different and fragmentary landscapes. Results obtained from monitoring 18 localities in Spain allow an outline of the aeropollen dynamics of some of these environments. The major pollen types are: I. trees: Pinus, Qvercus, Olea, Cupressaceae, 2. shrubs: Corylus, Pislacia and 3. herbs: Poaccae, Urticaceae, Chenopodiaceae-Amaranthaceae, Plantago and Asteraceae. In some locations Alnus, Artemisia, Buxus, Betula, Castanea, Eucalyptus, Populus, Ulmus, and Ephedra also have to be considered. Quantitatively, pollen from trees predominates over that from herbs and shrubs, although at some localities this trend varies. The first pollen grains found in the weekly atmospheric analyses are from trees (winter). In spring tree pollen grains share the atmosphere with herb pollen. For this reason it is usual to find peak values of pollen content in the atmosphere during this part of the year, while winter and autumn are characterized by low pollen counts.     

Influence of dental restorative materials on ESR biodosimetry in tooth enamel

Using an experimental model and PENELOPE Monte Carlo simulations, the effects of resin and amalgam on the absorbed doses in tooth enamel were studied to evaluate the feasibility of using restored teeth in electron spin resonance (ESR) dose reconstruction. The model consisted of a phantom containing a plate of these restorative materials placed between powered enamel layers exposed to X rays and a ??Co beam. The experimental results and simulations agreed, showing that the attenuation produced by amalgam and resin with a thickness of 1, 2, and 4 mm is similar to that produced by the enamel itself in the case of the radiation sources employed. For X rays and ??Co γ radiation the attenuation reached almost 100% and 40%, respectively. These results show that for ESR dose reconstruction, the use of all available enamel of a tooth leads to errors in the estimated dose due to attenuation effects in both healthy and restored teeth. Thus the importance of an enamel selection from different sides of the tooth surface to apply ESR dose reconstruction in the case of a practical situation is shown.     

Applications of DL-buthionine-[S,R]-sulfoximine deplete cellular glutathione and improve white spruce (Picea glauca) somatic embryo development

In white spruce (Picea glauca), an improvement of somatic embryo yield and quality can be achieved by applications of dl-buthionine-[S,R]-sulfoximine (BSO), which inhibits the biosynthesis of reduced glutathione (GSH), thereby switching the total glutathione pool towards its oxidized form (GSSG). Applications of BSO almost tripled the embryogenic output of two cell lines by increasing the number of embryos produced by 100 mg⁻¹ tissue from 65 to 154 in the (E)WS1 line and from 59 to 130 in the (E)WS2 line. This increase in embryo number was ascribed to a higher production of morphologically normal embryos with four or more cotyledons (group A embryos), at the expense of group B embryos, characterized by fewer cotyledons. The quality of the embryos produced, estimated by their post-embryonic performance, was also different between treatments. In both cell lines applications of BSO in the maturation medium increased the conversion frequency, i.e. root and shoot emergence, of group A embryos while it enhanced root emergence in group B embryos. Compared to their control counterparts, BSO-treated embryos had normal shoot apical meristems as in their zygotic counterparts. Such meristems were characterized by large apical cells and vacuolated sub-apical cells. They also lacked intercellular spaces, which were present in the apical poles of control embryos where they contributed to cell–cell separation and meristem degradation. Furthermore, storage product accumulation was also improved in the presence of BSO, with protein bodies prevailing over starch. These data show that an oxidized glutathione environment is beneficial for spruce embryo production in vitro.     

Bioelectricity and epimorphic regeneration

All cells have electric potentials across their membranes, but is there really compelling evidence to think that such potentials are used as instructional cues in developmental biology? Numerous reports indicate that, in fact, steady, weak bioelectric fields are observed throughout biology and function during diverse biological processes, including development. Bioelectric fields, generated upon amputation, are also likely to play a key role during vertebrate regeneration by providing the instructive cues needed to direct migrating cells to form a wound epithelium, a structure unique to regenerating animals. However, mechanistic insight is still sorely lacking in the field. What are the genes required for bioelectric‐dependent cell migration during regeneration? The power of genetics combined with the use of zebrafish offers the best opportunity for unbiased identification of the molecular players in bioelectricity. BioEssays 29:1133–1137, 2007. © 2007 Wiley Periodicals, Inc.     

EGFR controls IQGAP basolateral membrane localization and mitotic spindle orientation during epithelial morphogenesis

Establishing the correct orientation of the mitotic spindle is an essential step in epithelial cell division in order to ensure that epithelial tubules form correctly during organ development and regeneration. While recent findings have identified some of the molecular mechanisms that underlie spindle orientation, many aspects of this process remain poorly understood. Here, we have used the 3D‐MDCK model system to demonstrate a key role for a newly identified protein complex formed by IQGAP1 and the epithelial growth factor receptor (EGFR) in controlling the orientation of the mitotic spindle. IQGAP1 is a scaffolding protein that regulates many cellular pathways, from cell‐cell adhesion to microtubule organization, and its localization in the basolateral membrane ensures correct spindle orientation. Through its IQ motifs, IQGAP1 binds to EGFR, which is responsible for maintaining IQGAP1 in the basolateral membrane domain. Silencing IQGAP1, or disrupting the basolateral localization of either IQGAP1 or EGFR, results in a non‐polarized distribution of NuMA, mitotic spindle misorientation and defects in single lumen formation.     

Airborne pollen records and their potential applications to the conservation of biodiversity

The magnitude and complexity of the current erosion of plant biodiversity call for the development of interdisciplinary tools that enable an early detection of its effects and the establishment of effective management strategies. Indeed, plant sciences face the complex task of identifying the ecological information needed for the conservation challenge. Along this line should be placed the approach of aerobiology to gather the essential information for the development of plant recovery guidelines. In this work, we aim to discuss the potential role of airborne pollen monitoring in providing relevant data for the protection of plants and its potential applications to the management of plant diversity. To this end, we review three study cases where aerobiological monitoring can provide significant insights on conservation science. The present study is a contribution to plant conservation biology through long-term aeropalynological sampling, on the basis that pollen records constitute a suitable indicator for evaluating resource conservation of vegetation responding to environmental fluctuations. In view of its position between botany and meteorology, the contribution of aerobiological knowledge to biodiversity conservation can be very relevant and should be explored thoroughly.