An orally bioavailable positive allosteric modulator of the mGlu4 receptor with efficacy in an animal model of motor dysfunction

A high-throughput screening campaign identified 4-((E)-styryl)-pyrimidin-2-ylamine (11) as a positive allosteric modulator of the metabotropic glutamate (mGlu) receptor subtype 4. An evaluation of the structure–activity relationships (SAR) of 11 is described and the efficacy of this compound in a haloperidol-induced catalepsy rat model following oral administration is presented.     

Recovery of plant species composition and ecosystem function after cessation of grazing in a Mediterranean grassland

Short- and long-term changes in species composition, plant biomass production, and litter decomposition after cessation of grazing were examined in a Mediterranean grassland with high dominance of annual species and strong seasonality in biomass production. Short-term changes were assessed during three consecutive years in plots previously exposed to different grazing pressures and compared to plots in long-term (30–40 years) exclosures. Short-term cessation of grazing led in the short-term to an increase in relative biomass of annual crucifers and tall annual and perennial grasses, while biomass of annual legumes, annual thistles and short annual grasses decreased. Consequently, similarity increased between vegetation recently excluded from grazing and vegetation in long-term protected plots. Our research showed that in systems with high dominance of grasses and annual species, the rapid changes in plant species composition that occur after grazing cessation were associated with a fast recovery of the potential for biomass production to levels found in long-term protected plots, while litter decomposition rate did not change even after long-term cessation of grazing. Moreover, previous history of grazing did not affect plant litter decomposition, despite higher litter quality in grazed treatments. This study provides new insights about the processes involved in the diverse responses of ecosystem functions resulting from shifts in species composition associated with grazing cessation and land use change in Mediterranean grasslands.     

Variation in ovule and seed size and associated size-number trade-offs in angiosperms

Unlike pollen and seed size, the extent and causes of variation in ovule size remain unexplored. Based on 45 angiosperm species, we assessed whether intra- and interspecific variation in ovule size is consistent with cost minimization during ovule production or allows maternal plants to dominate conflict with their seeds concerning resource investment. Despite considerable intraspecific variation in ovule volume (mean CV = 0.356), ovule production by few species was subject to a size-number trade-off. Among the sampled species, ovule volume varied two orders of magnitude, whereas seed volume varied four orders of magnitude. Ovule volume varied positively among species with flower mass and negatively with ovule number. Tenuinucellate ovules were generally larger that crassinucellate ovules, and species with apical placentation (which mostly have uniovulate ovaries) had smaller ovules than those with other placentation types. Seed volume varied positively among species with fruit mass and seed development time, but negatively with seed number. Seeds grew a median 93-fold larger than the ovules from which they originated. Our results provide equivocal evidence that selection minimizes ovule size to allow efficient resource allocation after fertilization, but stronger evidence that ovule size affords maternal plants an advantage in parent-offspring conflict.     

Characterization of wheat germin (oxalate oxidase) expressed by Pichia pastoris

High-level secretory expression of wheat (Triticum aestivum) germin/oxalate oxidase was achieved in Pichia pastoris fermentation cultures as an alpha-mating factor signal peptide fusion, based on the native wheat cDNA coding sequence. The oxalate oxidase activity of the recombinant enzyme is substantially increased (7-fold) by treatment with sodium periodate, followed by ascorbate reduction. Using these methods, approximately 1 g (4x10(4) U) of purified, activated enzyme was obtained following eight days of induction of a high density Pichia fermentation culture, demonstrating suitability for large-scale production of oxalate oxidase for biotechnological applications. Characterization of the recombinant protein shows that it is glycosylated, with N-linked glycan attached at Asn47. For potential biomedical applications, a nonglycosylated (S49A) variant was also prepared which retains essentially full enzyme activity, but exhibits altered protein-protein interactions.     

Sequence-level population simulations over large genomic regions

Simulation is an invaluable tool for investigating the effects of various population genetics modeling assumptions on resulting patterns of genetic diversity, and for assessing the performance of statistical techniques, for example those designed to detect and measure the genomic effects of selection. It is also used to investigate the effectiveness of various design options for genetic association studies. Backward-in-time simulation methods are computationally efficient and have become widely used since their introduction in the 1980s. The forward-in-time approach has substantial advantages in terms of accuracy and modeling flexibility, but at greater computational cost. We have developed flexible and efficient simulation software and a rescaling technique to aid computational efficiency that together allow the simulation of sequence-level data over large genomic regions in entire diploid populations under various scenarios for demography, mutation, selection, and recombination, the latter including hotspots and gene conversion. Our forward evolution of genomic regions (FREGENE) software is freely available from www.ebi.ac.uk/projects/BARGEN together with an ancillary program to generate phenotype labels, either binary or quantitative. In this article we discuss limitations of coalescent-based simulation, introduce the rescaling technique that makes large-scale forward-in-time simulation feasible, and demonstrate the utility of various features of FREGENE, many not previously available.     

Mitotic phosphorylation of PRC1 at Thr470 is required for PRC1 oligomerization and proper central spindle organization

During cell division, chromosome segregation is orchestrated by the interaction of spindle microtubules with thecentromere. A dramatic remodeling of interpolar microtubules into an organized central spindle between the separatingchromatids is required for the initiation and execution of cytokinesis. Central spindle organization requires mitotic kine-sins, the chromosomal passenger protein complex, and microtubule bundling protein PRC1. PRC1 is phosphorylated byCdc2 at Thr470 and Thr481 during mitosis. However, the functional relevance of PRC1 phosphorylation at Thr470 hasremained elusive. Here we show that expression of the non-phosphorylatable mutant PRC1~(T470A) but not the phospho-mimi-cking mutant PRC1~(T470E) causes aberrant organization of the central spindle. Immunoprecipitation experiment indicatesthat both PRC1~(T470A) and PRC1~(T470E) mutant proteins associate with wild-type PRC1, suggesting that phosphorylationof Thr470 does not alter PRC1 self-association. In addition, in vitro co-sedimentation experiment showed that PRC1binds to microtubule independent of the phosphorylation state of Thr470. Gel-filtration experiment suggested that phos-phorylation of Thr470 promotes oligomerization of PRC1. Given the fact that prevention of the Thr470 phosphorylationinhibits PRC1 oligomerization in vitro and causes an aberrant organization of central spindle in vivo, we propose thatthis phosphorylation-dependent PRC1 oligomerization ensures that central spindle assembly occurs at the appropriatetime in the cell cycle.     

How resilient are Andean montane forest bird communities to habitat degradation?

The threatened forest habitats of the tropical Andes are reportedly being modified and destroyed 30% faster than their lowland tropical counterparts, but impacts on the hyper-diverse resident avifauna have received little systematic study. We present a baseline analysis of the effects of habitat modification on birds in a lower montane forest landscape in Ecuador, comparing avian community composition in landscape elements subjected to different levels of human modification: primary forest, secondary forest, edge habitat and agricultural land. We use data from a point count survey of 300 counts at 150 sites to test whether community composition and density of birds with different reported habitat preferences and foraging strategies change among landscape elements. Species richness and diversity were lowest in agricultural land, but on some measures, equally low in primary forest. Richness and diversity peaked in secondary forest and edge habitat, but ordination and density analysis revealed clear differences in their species composition. While secondary forest contained mostly forest-preferring species, edge habitat harboured a mix of forest and open-land birds. There was a clearly structured gradient in species composition across landscape elements, with densities of habitat specialists, foraging guilds and families varying considerably from primary forest to agricultural land. Agricultural land was characterised by an assemblage of widespread, abundant species very different from that in core forest habitats. As such, while the majority of montane forest birds appear resilient to a certain level of habitat modification, they cannot persist, and are displaced, where forest has been cleared outright. We argue that, for Andean montane forests, preservation of mature secondary forest offers flexibility in supplementing preserved primary forest areas to provide sufficient habitat for the persistence of this incredibly diverse but severely threatened bird community.     

Enhancing nonhuman primate care and welfare through the use of positive reinforcement training

Nonhuman primates are excellent subjects for the enhancement of care and welfare through training. The broad range of species offers tremendous behavioral diversity, and individual primates show varying abilities to cope with the stressors of captivity, which differ depending on the venue. Biomedical facilities include small single cages, pair housing, and breeding corrals with large social groups. Zoos have social groupings of differing sizes, emphasizing public display and breeding. Sanctuaries have nonbreeding groups of varying sizes and often of mixed species. In every venue, the primary objective is to provide good quality care, with minimal stress. Positive reinforcement training improves care and reduces stress by enlisting a primate's voluntary cooperation with targeted activities, including both husbandry and medical procedures. It can also improve socialization, reduce abnormal behaviors, and increase species-typical behaviors. This article reviews the results already achieved with positive reinforcement training and suggests further possibilities for enhancing primate care and welfare.