Non-woody life-form contribution to vascular plant species richness in a tropical American forest

We provide total vascular plant species counts for three 1-ha plots in deciduous, semi-deciduous and evergreen forests in central Bolivia. Species richness ranged from 297 species and 22,360 individuals/ha in the dry deciduous forest to 382 species and 31,670 individuals/ha in the evergreen forest. Orchidaceae, Pteridophyta and Leguminosae were among the most species-rich major plant groups in each plot, and Peperomia (Piperaceae), Pleurothallis (Orchidaceae) and Tillandsia (Bromeliaceae), all epiphytes, were the most species-rich genera. This dominance of a few but very diverse and/or widespread taxa contrasted with the low compositional similarity between plots. In a neotropical context, these Central Bolivian forest plots are similar in total species richness to other dry deciduous and humid montane forests, but less rich than most Amazonian forests. Nevertheless, lianas, terrestrial herbs and especially epiphytes proved to be of equal or higher species richness than most other neotropical forest inventories from which data are available. We therefore highlight the importance of non-woody life-forms (especially epiphytes and terrestrial herbs) in Andean foothill forest ecosystems in terms of species richness and numbers of individuals, representing in some cases nearly 50% of the species and more than 75% of the individuals. These figures stress the need for an increased inventory effort on non-woody plant groups in order to accurately direct conservation actions. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Periplasmic metal-resistance protein CusF exhibits high affinity and specificity for both CuI and AgI

The periplasmic protein CusF, as a part of the CusCFBA efflux complex, plays a role in resistance to elevated levels of copper and silver in Escherichia coli. Although homologues have been identified in other Gram-negative bacteria, the substrate of CusF and its precise role in metal resistance have not been described. Here, isothermal titration calorimetry (ITC) was used to demonstrate that CusF binds with high affinity to both Cu(I) and Ag(I) but not Cu(II). The affinity of CusF for Ag(I) was higher than that for Cu(I), which could reflect more efficient detoxification of Ag(I) given the lack of a cellular need for Ag(I). The chemical shifts in the nuclear magnetic resonance (NMR) spectra of CusF-Ag(I) as compared to apo-CusF show that the region of CusF most affected by Ag(I) binding encompasses three absolutely conserved residues: H36, M47, and M49. This suggests that these residues may play a role in Ag(I) coordination. The NMR spectra of CusF in the presence of Cu(II) do not indicate specific binding, which is in agreement with the ITC data. We conclude that Cu(I) and Ag(I) are the likely physiological substrates.     

Neuronal differentiation of human mesenchymal stem cells: changes in the expression of the Alzheimer's disease-related gene seladin-1

Seladin-1 (SELective Alzheimer's Disease INdicator-1) is an anti-apoptotic gene, which is down-regulated in brain regions affected by Alzheimer's disease (AD). In addition, seladin-1 catalyzes the conversion of desmosterol into cholesterol. Disruption of cholesterol homeostasis in neurons may increase cell susceptibility to toxic agents. Because the hippocampus and the subventricular zone, which are affected in AD, are the unique regions containing stem cells with neurogenic potential in the adult brain, it might be hypothesized that this multipotent cell compartment is the predominant source of seladin-1 in normal brain. In the present study, we isolated and characterized human mesenchymal stem cells (hMSC) as a model of cells with the ability to differentiate into neurons. hMSC were then differentiated toward a neuronal phenotype (hMSC-n). These cells were thoroughly characterized and proved to be neurons, as assessed by molecular and electrophysiological evaluation. Seladin-1 expression was determined and found to be significantly reduced in hMSC-n compared to undifferentiated cells. Accordingly, the total content of cholesterol was decreased after differentiation. These original results demonstrate for the first time that seladin-1 is abundantly expressed by stem cells and appear to suggest that reduced expression in AD might be due to an altered pool of multipotent cells.     

Phenotypic characterization of telomerase-immortalized primary non-malignant and malignant tumor-derived human prostate epithelial cell lines

In vitro human prostate cell culture models are critical for clarifying the mechanism of prostate cancer progression and for testing preventive and therapeutic agents. Cell lines ideal for the study of human primary prostate tumors would be those derived from spontaneously immortalized tumor cells; unfortunately, explanted primary prostate cells survive only short-term in culture, and rarely immortalize spontaneously. Therefore, we recently have generated five immortal human prostate epithelial cell cultures derived from both the benign and malignant tissues of prostate cancer patients with telomerase, a gene that prevents cellular senescence. Examination of these cell lines for their morphologies and proliferative capacities, their abilities to grow in low serum, to respond to androgen stimulation, to grow above the agar layer, to form tumors in SCID mice, suggests that they may serve as valid, useful tools for the elucidation of early events in prostate tumorigenesis. Furthermore, the chromosome alterations observed in these immortalized cell lines expressing aspects of the malignant phenotypes imply that these cell lines accurately recapitulate the genetic composition of primary tumors. These novel in vitro models may offer unique models for the study of prostate carcinogenesis and also provide the means for testing both chemopreventive and chemotherapeutic agents.     

Spirits out of place: relational landscapes and environmental change in East Kalimantan,Indonesia

This article examines interaction with spirits among the Luangan, a group of shifting cultivators in Indonesian Borneo. Through examples of different forms of Luangan spirit interaction, it interrogates the relationship between the spirit world and the natural environment, with special reference to what happens when the latter undergoes dramatic change. Inspired by Eduardo Kohn's understanding of how the spirit world is semiotically embedded within the rainforest environment, I explore how relations with nonhumans reflect historical and ongoing experiences of life and sociality in the forest and human domain, while superimposing a virtual relational landscape upon the natural landscape. It is proposed that spirit communication offers a means of refiguring human lives and alleviating debilitation, and that recurrent rituals enable Luangans to virtually maintain relations with unseen beings of the local environment, even where it has been thoroughly transformed through oil palm cultivation.     

Plasma lipid profiling in a large population-based cohort

We have performed plasma lipid profiling using liquid chromatography electrospray ionization tandem mass spectrometry on a population cohort of more than 1,000 individuals. From 10 μl of plasma we were able to acquire comparative measures of 312 lipids across 23 lipid classes and subclasses including sphingolipids, phospholipids, glycerolipids, and cholesterol esters (CEs) in 20 min. Using linear and logistic regression, we identified statistically significant associations of lipid classes, subclasses, and individual lipid species with anthropometric and physiological measures. In addition to the expected associations of CEs and triacylglycerol with age, sex, and body mass index (BMI), ceramide was significantly higher in males and was independently associated with age and BMI. Associations were also observed for sphingomyelin with age but this lipid subclass was lower in males. Lysophospholipids were associated with age and higher in males, but showed a strong negative association with BMI. Many of these lipids have previously been associated with chronic diseases including cardiovascular disease and may mediate the interactions of age, sex, and obesity with disease risk.