Refine
Document Type
- Article (7)
Language
- English (7)
Has Fulltext
- yes (7)
Is part of the Bibliography
- no (7)
Keywords
- Data sharing (1)
- global change (1)
- habitat destruction (1)
- land use (1)
Background: Alzheimer's disease is a common debilitating dementia with known heritability, for which 20 late onset susceptibility loci have been identified, but more remain to be discovered. This study sought to identify new susceptibility genes, using an alternative gene-wide analytical approach which tests for patterns of association within genes, in the powerful genome-wide association dataset of the International Genomics of Alzheimer's Project Consortium, comprising over 7 m genotypes from 25,580 Alzheimer's cases and 48,466 controls.
Principal findings: In addition to earlier reported genes, we detected genome-wide significant loci on chromosomes 8 (TP53INP1, p = 1.4×10−6) and 14 (IGHV1-67 p = 7.9×10−8) which indexed novel susceptibility loci.
Significance: The additional genes identified in this study, have an array of functions previously implicated in Alzheimer's disease, including aspects of energy metabolism, protein degradation and the immune system and add further weight to these pathways as potential therapeutic targets in Alzheimer's disease.
Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups – including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems – www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.
Psoriatic arthritis (PsA) is a chronic inflammatory arthritis associated with psoriasis and, despite the larger estimated heritability for PsA, the majority of genetic susceptibility loci identified to date are shared with psoriasis. Here, we present results from a case-control association study on 1,962 PsA patients and 8,923 controls using the Immunochip genotyping array. We identify eight loci passing genome-wide significance, secondary independent effects at three loci and a distinct PsA-specific variant at the IL23R locus. We report two novel loci and evidence of a novel PsA-specific association at chromosome 5q31. Imputation of classical HLA alleles, amino acids and SNPs across the MHC region highlights three independent associations to class I genes. Finally, we find an enrichment of associated variants to markers of open chromatin in CD8(+) memory primary T cells. This study identifies key insights into the genetics of PsA that could begin to explain fundamental differences between psoriasis and PsA.
Subalpine shrubs on rocky slopes on the Bogong High Plains, Victoria (36° 53’ S, 147° 19’ E), were observed to be severely desiccated over the summer of 2002/03 after a 50 day period when only 1.2 mm of rainfall was recorded. Moderate to severe canopy dieback was noted in shrubs growing on rocky north- and west-facing slopes. Four shrubs were assessed for their drought tolerance on west-facing slopes at Basalt Hill. Soils were rocky and uniformly shallow across the site (mean depth = 11.32 ± 0.69 cm). Prostanthera cuneata was the most drought tolerant species (as evidenced by the least amount of canopy dieback observed) followed by Hovea montana, Pimelea axiflora var. alpina and Epacris glacialis. All Epacris glacialis plants (n = 16) had died at the study location whereas no Prostanthera cuneata plants (n = 45) had canopy dieback that exceeded 60%. The amount of dieback observed was not significantly associated with either local soil depth or shrub canopy area. Hence, very small plants were not more susceptible to drought nor were shrubs found on the shallowest of the soils at the site. This suggests that drought effects are possibly dependent on local influences such as topography, drainage and competition intensity. Drought has only rarely been considered a major factor affecting the abundance and distribution of subalpine shrub species in Australia but this study suggests that it should be added to the list of abiotic factors governing the local dynamics of subalpine vegetation. In particular, the high mortality of Epacris glacialis observed in the study area suggests that non-equilibrium dynamics are likely to be the "norm" for some shrubs in subalpine areas.
Bryophyte composition in a native grassland community subjected to different long-term fire regimes
(2004)
The vascular species composition of volcanic plains grassland remnants of western Victoria is strongly tied to management history, with frequently burned remnants often supporting the most diverse native flora relative to grazed and long-unburned remnants. How the fire regime affects the composition of the bryophytic mat, however, has not been documented. I surveyed the moss and liverwort flora of six Themeda triandra grasslands subjected to different long-term fire regimes to understand how fire might affect mat composition. A total of 27 non-vascular species (19 mosses and 8 liverworts) were recorded, of which nine species were recorded only from a single location. Non-vascular species contributed 28% of the total diversity observed in this study. The liverwort Lethocolea pansa was the most obvious species at all sites, while the mosses Rosulabryum billardieri and Fossombronia intestinalis were also found at all sites and hence, would appear to be robust to fire at different frequencies. Frequently-burned (1–2 yr interval) grasslands generally had lower mat species richness than longer-unburned sites (4 to >20 yr intervals) and appear to support a subset of the flora (due to the loss of moss species) rather than a distinctly different flora. The preliminary results of this study contrast with the evidence usually found for vascular species, i.e. that frequent fire favours greater native species richness. Hence, the two components of the flora would appear to respond in different ways to fire and this should be considered in the conservation planning for this grassland community. Further field sampling is warranted to confirm the initial trends identified by this study.
Floristic variation in Sphagnum-dominated peatland communities of the Central Highlands, Victoria
(2007)
The floristic composition of Sphagnum-dominated peatlands in the Central Highlands region of Victoria was surveyed (37º 25´ S; 145º 50´ E). NMDS ordination and cluster analysis divided the peatland sites into two broad groups with altitude being the most important factor separating these groups. Other important factors were aspect, slope and the amount of shade. Group 1 included subalpine sites that are similar to those found at higher altitudes further east in Victoria. Important species included Empodisma minus, Epacris paludosa, Richea continentis and Baeckea gunniana. The two species of Sphagnum present were Sphagnum cristatum and the more inundation-tolerant Sphagnum novozelandicum. Group 2 included montane peatlands with abundant Sphagnum cristatum. These sites range from broad wet heaths dominated by Richea victoriana and Carex appressa, to narrower cool temperate rainforest and riparian systems. The ‘rainforest’ peatlands are characterised by Leptospermum grandifolium, Nothofagus cunninghamii, Carex appressa and Blechnum penna-marina, and are in varying stages of post-fire succession regulated by sitespecific microclimate. The conservation status and catchment function of these peatlands are briefly discussed.
Following wildfire in 2005 at Wilsons Promontory, Victoria, we asked how fire severity affected the postfire regeneration of dominant woody species in two coastal plant communities. We documented the effects of fire severity (unburned, low, high) on stand mortality and seedling regeneration in shrublands dominated by the obligate seeder Leptospermum laevigatum (Myrtaceae) and woodlands dominated by the resprouting Banksia integrifolia var. integrifolia (Proteaceae). Leptospermum laevigatum is a range-expanding native species that has encroached into grassy Banksia woodland and hence, we were also interested whether fire severity affects post-fire succession in encroached and un-encroached stands. Fire severity impacted on all measures of post-fire recovery examined: stand mortality, seedling germination, seedling survival, seedling growth. High fire severity (complete canopy consumption) led to 100% mortality of both species. Despite variable responses at the stand level, mean Leptospermum laevigatum seedling establishment, growth and survival all increased with increasing fire severity in shrublands, thus ensuring shrublands are replaced. Banksia integrifolia recruitment, however, was minimal in all stands and not fire-cued. Increasing fire severity enabled Leptospermum laevigatum to recruit into woodland sites from where it was previously absent and this establishment, coupled with the loss of overstorey Banksia trees, may rapidly transform woodlands into shrublands. Hence, fire severity-induced population responses were observed and these imprints are likely to affect longer-term succession by reinforcing site occupancy of the encroaching Leptospermum laevigatum while simultaneously leading to the potential decline of Banksia woodlands.