Unraveling the molecular basis for ligand binding in truncated hemoglobins: The trHbO Bacillus subtilis case

Truncated hemoglobins (trHbs) are heme proteins present in bacteria, unicellular eukaryotes, and higher plants. Their tertiary structure consists in a 2‐over‐2 helical sandwich, which display typically an inner tunnel/cavity system for ligand migration and/or storage. The microorganism Bacillus subtilis contains a peculiar trHb, which does not show an evident tunnel/cavity system connecting the protein active site with the solvent, and exhibits anyway a very high oxygen association rate. Moreover, resonant Raman results of CO bound protein, showed that a complex hydrogen bond network exists in the distal cavity, making it difficult to assign unambiguously the residues involved in the stabilization of the bound ligand. To understand these experimental results with atomistic detail, we performed classical molecular dynamics simulations of the oxy, carboxy, and deoxy proteins. The free energy profiles for ligand migration suggest that there is a key residue, GlnE11, that presents an alternate conformation, in which a wide ligand migration tunnel is formed, consistently with the kinetic data. This tunnel is topologically related to the one found in group I trHbs. On the other hand, the results for the CO and O₂ bound protein show that GlnE11 is directly involved in the stabilization of the cordinated ligand, playing a similar role as TyrB10 and TrpG8 in other trHbs. Our results not only reconcile the structural data with the kinetic information, but also provide additional insight into the general behaviour of trHbs. Proteins 2010. © 2009 Wiley‐Liss, Inc.     

Understanding investment in biodiversity conservation in Mexico

Documenting financial resources in biodiversity conservation is a key aspect worldwide in order to set priorities and use effectively the limited resources available. In Mexico, a megadiverse country, studies on financial resources invested in biodiversity conservation are scarce and do not address funding for conservation comprehensively. Using recent data from several sources and applying criteria based on the national priorities for conservation, we compiled, systematized and analyzed data at a national scale on financing sources, financial resources and conservation organizations and their projects. The information obtained is presented in various ways and part of it (case study) is already an information system that can be continuously up-dated. Some of the results show the following: a steady diversification of mechanisms and methods for raising funds for conservation; an increase in governmental budgets; the acknowledgment by the private sector of the importance of biodiversity conservation; a greater technical capacity in people and organizations working in conservation; a greater accessibility of financial resources to support and maintain conservation projects; yet a short term vision in conservation projects; among other. Although the results obtained through this study are a first approach, they can now be used as a baseline to continue gathering and analyzing information on conservation financing in Mexico.     

Effect of Game Management on Wild Red-Legged Partridge Abundance

The reduction of game and fish populations has increased investment in management practices. Hunting and fishing managers use several tools to maximize harvest. Managers need to know the impact their management has on wild populations. This issue is especially important to improve management efficacy and biodiversity conservation. We used questionnaires and field bird surveys in 48 hunting estates to assess whether red-legged partridge Alectoris rufa young/adult ratio and summer abundance were related to the intensity of management (provision of supplementary food and water, predator control and releases of farm-bred partridges), harvest intensity or habitat in Central Spain. We hypothesized that partridge abundance would be higher where management practices were applied more intensively. Variation in young/adult ratio among estates was best explained by habitat, year and some management practices. Density of feeders and water points had a positive relationship with this ratio, while the density of partridges released and magpies controlled were negatively related to it. The variables with greatest relative importance were feeders, releases and year. Variations in post-breeding red-legged partridge abundance among estates were best explained by habitat, year, the same management variables that influenced young/adult ratio, and harvest intensity. Harvest intensity was negatively related to partridge abundance. The other management variables had the same type of relationship with abundance as with young/adult ratio, except magpie control. Variables with greatest relative importance were habitat, feeders, water points, releases and harvest intensity. Our study suggests that management had an overall important effect on post-breeding partridge abundance. However, this effect varied among tools, as some had the desired effect (increase in partridge abundance), whereas others did not or even had a negative relationship (such as release of farm-reared birds) and can be thus considered inefficient or even detrimental. We advise reconsidering their use from both ecological and economical points of view.     

Isolation and characterization of 13 microsatellite loci for Neochamaelea pulverulenta (Cneoraceae)

We report 13 polymorphic nuclear microsatellite loci for Neochamaelea pulverulenta (Cneoraceae) using an enriched-library approach. Although this plant species is tetraploid, expected patterns for tetrasomic segregation were completely absent, and all loci analysed showed a diploid pattern of inheritance. We detected a total of 102 alleles in 57 individuals genotyped (mean number of alleles per locus was 7.85). The values of observed and expected heterozygosities ranged from 0.193 to 0.737 and 0.425 to 0.812 respectively. Disomic segregation, levels of polymorphism and the exclusionary power of the developed markers render them readily applicable for parentage assignment of dispersed seeds, and for analyses of spatial genetic structure and population connectivity.     

Regional differences in land use affect population performance of the threatened insectivorous plant Drosophyllum lusitanicum (Droseraceae)

Abstract. We analyse populations of the insectivorous plant Drosophyllum lusitanicum (L.) Link (Droseraceae) and their habitats throughout the species' distribution range (Portugal, Spain and Morocco), and examine their relations. We have surveyed 32 populations and we analyse their demographic structures, accompanying plant communities (by twinspan analyses), and relationships between population features and several edaphic and nonedaphic environmental variables (by multiple regression analyses). Plant communities, their floristic richness and degree of endemism change across the geographical range of Drosophyllum . Populations vary strongly in size, density and age structure. Their recruitment seems largely determined by competition with the surrounding vegetation, while only weak relationships were detected between population performance and other environmental factors. The demographic structure of populations exhibits a marked geographical differentiation, with populations becoming older and sparser towards the north-western part of the range. The largest and presumably most stable populations are mostly found in southern Spanish heathlands, which are nowadays scarcely affected by man. Moroccan populations suffer from browsing by cattle and experience an accelerated generation turnover, while most Portuguese populations occur in afforested areas and experience strongly reduced recruitment. The historical distribution range of Drosophyllum within its peculiar habitat has probably been relatively stable, but recent regional differences in human land use have resulted in present-day differences in population performance, as well as in types and degrees of threat across the three countries involved. Conservation strategies should take into account this range-wide variation and combine approaches on different spatial scales.     

Phylogenetic reconstruction of the genus Triptilion (Asteraceae,Nassauvieae) based on nuclear and chloroplast DNA sequences

The genus Triptilion is endemic to central Chile, the Mendoza Province and western Patagonia in Argentina. It is currently composed of seven species: T. achilleae, T. benaventii, T. berteroi, T. capillatum, T. cordifolium, T. gibbosum, and T. spinosum. The main objectives of this paper were to determine the phylogenetic relationships of species of Triptilion. We also traced the evolution of annual and perennial life-forms. Historically a close relationship has been described between genera Triptilion and Nassauvia. Phylogenetic analysis of the genus Triptilion and more closely related genera was undertaken using two nuclear (ITS, ETS) and two chloroplast (trnL-F, rpl32-trnL) markers. The topology of the Bayesian inference tree shows that the genus Triptilion is paraphyletic, because Nassauvia lagascae, the only representative of Nassauvia section Caloptilium grouped with T. achilleae, Clade I. The other species of Triptilion form two clades: Clade II composed of T. cordifolium and T. gibbosum and Clade III that includes T. benaventii, T. berteroi, T. capillatum, and T. spinosum. The genus Triptilion originated and diverged during the Miocene. The results of the life history reconstructions indicate that the common ancestor of Triptilion and Nassauvia was perennial. The annual habit appears to be derived in Triptilion. The life-form of the common ancestor of Triptilion was ambiguous; it may have been annual or perennial.