Contrasting palm species and use diversity in the Yucatan Peninsula and the Ecuadorian Amazon

We analyze the relationship between palm species diversity and diversity of palm use in two areas (Amazonian Ecuador; Yucatan Peninsula) of equivalent size but with contrasting characteristics in palm species diversity and morphology, and in the phylogenetic composition of palm flora. The areas also differ in their cultural and socioeconomic contexts. Palm use diversity is significantly higher in the Ecuadorian Amazon than in the Yucatan Peninsula and the lower species diversity of palms in the Yucatan Peninsula is not matched by a more intensive use of the fewer species found there. The taxonomic composition of the palm flora is a poor predictor of extent of use and morphological characteristics of palm species affect usefulness only in the Ecuadorian Amazon. The Yucatecans’ more limited reliance on forest products might explain the observed patterns. Ornamental palm use is an indicator of a general change in plant use patterns associated with tourism and macro-economic development in the Yucatan Peninsula. We find a positive relationship between ecosystem plant diversity and plant use diversity, but socioeconomic factors such as market integration strongly influence the use of local biodiversity. Palms represent a diverse and important natural resource that deserves further investigation to secure its sustainable management and conservation in the two studied sites, regardless of their degree of market integration.     

Biophysical studies of the membrane location of the voltage-gated sensors in the HsapBK and KvAP K channels

The membrane location of two fragments in two different K⁺-channels, the KvAP (from Aeropyrum pernix) and the HsapBK (human) corresponding to the putative “paddle” domains, has been investigated by CD, fluorescence and NMR spectroscopy. Both domains interact with q = 0.5 phospholipid bicelles, DHPC micelles and with POPC vesicles. CD spectra demonstrate that both peptides become largely helical in the presence of phospholipid bicelles. Fluorescence quenching studies using soluble acrylamide or lipid-attached doxyl-groups show that the arginine-rich domains are located within the bilayered region in phospholipid bicelles. Nuclear magnetic relaxation parameters, T₁ and ¹³C-¹H NOE, for DMPC in DMPC/DHPC bicelles and for DHPC in micelles showed that the lipid acyl chains in the bicelles become less flexible in the presence of either of the fragments. An even more pronounced effect is seen on the glycerol carbons. ²H NMR spectra of magnetically aligned bicelles showed that the peptide derived from KvAP had no or little effect on bilayer order, while the peptide derived from HsapBK had the effect of lowering the order of the bilayer. The present study demonstrates that the fragments derived from the full-length proteins interact with the bilayered interior of model membranes, and that they affect both the local mobility and lipid order of model membrane systems.     

Sex-specific fitness correlates of dispersal in a house sparrow metapopulation

1.  Dispersal affects many important ecological and evolutionary processes. Still, little is known about the fitness of dispersing individuals.
2.  Here, we use data from a long-term study of a house sparrow Passer domesticus metapopulation to compare lifetime reproductive success (LRS) of resident and immigrant individuals, all with known origin.
3.  Lifetime production of recruits by immigrant males was much lower than for resident males, because of shorter life span and lower annual mating success. In contrast, lifetime production of recruits did not differ significantly between immigrant and resident females.
4.  Over their lifetime, dispersers contributed fewer recruits to the local population than residents. This shows that immigrant house sparrows have different, sex specific, demographic effects on the population dynamics than residents.     

Secreted Protein Acidic and Rich in Cysteine (SPARC) in Human Skeletal Muscle

Secreted protein acidic and rich in cysteine (SPARC)/osteonectin is expressed in different tissues during remodeling and repair, suggesting a function in regeneration. Several gene expression studies indicated that SPARC was expressed in response to muscle damage. Studies on myoblasts further indicated a function of SPARC in skeletal muscle. We therefore found it of interest to study SPARC expression in human skeletal muscle during development and in biopsies from Duchenne and Becker muscular dystrophy and congenital muscular dystrophy, congenital myopathy, inclusion body myositis, and polymyositis patients to analyze SPARC expression in a selected range of inherited and idiopathic muscle wasting diseases. SPARC-positive cells were observed both in fetal and neonatal muscle, and in addition, fetal myofibers were observed to express SPARC at the age of 15–16 weeks. SPARC protein was detected in the majority of analyzed muscle biopsies (23 of 24), mainly in mononuclear cells of which few were pax7 positive. Myotubes and regenerating myofibers also expressed SPARC. The expression-degree seemed to reflect the severity of the lesion. In accordance with these in vivo findings, primary human-derived satellite cells were found to express SPARC both during proliferation and differentiation in vitro. In conclusion, this study shows SPARC expression both during muscle development and in regenerating muscle. The expression is detected both in satellite cells/myoblasts and in myotubes and muscle fibers, indicating a role for SPARC in the skeletal muscle compartment. (J Histochem Cytochem 57:29–39, 2009)     

Cephalanthera exigua rediscovered: new insights in the taxonomy,habitat requirements and breeding system of a rare mycoheterotrophic orchid

Five mycoheterotrophic species of Cephalanthera have been proposed from tropical Asia. Until recently, all of them were only known from the type specimens, for which reason it has been difficult to judge if some of them were actually conspecific. The recent discovery of two large populations of C. exigua in Thailand made it possible to describe the range of variation of this species in much more detail, and we then found it to be well distinguished from the others. A phylogenetic analysis based on nuclear rDNA ITS sequences corroborated the systematic position of C. exigua at the generic level. Examination of the previously neglected type of C. pusilla from Myanmar lead to the conclusion that this taxon of disputed generic affinity likewise belongs to Cephalanthera, and that it is a clearly distinct species. Finally, we accept that also C. ericiflora from Laos as well as C. gracilis and C. calcarata from Yunnan are probably distinct species. Cephalanthera exigua grows in hill evergreen forest, but we found little floristic similarity between its two localities in Thailand (IS_S=22.5%). Ectomycorrhizal trees of the families Fagaceae and Ulmaceae are probably the ultimate carbon source for C. exigua at both sites, as the mycorrhizal partners of this orchid (basidiomycetes of the family Thelephoraceae) obtain their carbon nutrition through ectomycorrhizal association with forest trees. Pollination experiments demonstrated that the nectarless flowers of C. exigua are not spontaneously autogamous. Based on the pollination syndrome and previously published observations on other species of the genus, we suggest that C. exigua has an insect‐operated breeding system acting by deceit, and that the pollinators are probably solitary bees.     

A global view of protein expression in human cells,tissues, and organs

Defining the protein profiles of tissues and organs is critical to understanding the unique characteristics of the various cell types in the human body. In this study, we report on an anatomically comprehensive analysis of 4842 protein profiles in 48 human tissues and 45 human cell lines. A detailed analysis of over 2 million manually annotated, high‐resolution, immunohistochemistry‐based images showed a high fraction (>65%) of expressed proteins in most cells and tissues, with very few proteins (<2%) detected in any single cell type. Similarly, confocal microscopy in three human cell lines detected expression of more than 70% of the analyzed proteins. Despite this ubiquitous expression, hierarchical clustering analysis, based on global protein expression patterns, shows that the analyzed cells can be still subdivided into groups according to the current concepts of histology and cellular differentiation. This study suggests that tissue specificity is achieved by precise regulation of protein levels in space and time, and that different tissues in the body acquire their unique characteristics by controlling not which proteins are expressed but how much of each is produced.