℮-conome: an automated tissue counting platform of cone photoreceptors for rodent models of retinitis pigmentosa

<p>Abstract</p> <p>Background</p> <p>Retinitis pigmentosa is characterized by the sequential loss of rod and cone photoreceptors. The preservation of cones would prevent blindness due to their essential role in human vision. Rod-derived Cone Viability Factor is a thioredoxin-like protein that is secreted by rods and is involved in cone survival. To validate the activity of Rod-derived Cone Viability Factors (RdCVFs) as therapeutic agents for treating retinitis Pigmentosa, we have developed e-conome, an automated cell counting platform for retinal flat mounts of rodent models of cone degeneration. This automated quantification method allows for faster data analysis thereby accelerating translational research.</p> <p>Methods</p> <p>An inverted fluorescent microscope, motorized and coupled to a CCD camera records images of cones labeled with fluorescent peanut agglutinin lectin on flat-mounted retinas. In an average of 300 fields per retina, nine Z-planes at magnification X40 are acquired after two-stage autofocus individually for each field. The projection of the stack of 9 images is subject to a threshold, filtered to exclude aberrant images based on preset variables. The cones are identified by treating the resulting image using 13 variables empirically determined. The cone density is calculated over the 300 fields.</p> <p>Results</p> <p>The method was validated by comparison to the conventional stereological counting. The decrease in cone density in <it>rd1 </it>mouse was found to be equivalent to the decrease determined by stereological counting. We also studied the spatiotemporal pattern of the degeneration of cones in the <it>rd1 </it>mouse and show that while the reduction in cone density starts in the central part of the retina, cone degeneration progresses at the same speed over the whole retinal surface. We finally show that for mice with an inactivation of the Nucleoredoxin-like genes <it>Nxnl1 </it>or <it>Nxnl2 </it>encoding RdCVFs, the loss of cones is more pronounced in the ventral retina.</p> <p>Conclusion</p> <p>The automated platform ℮-conome used here for retinal disease is a tool that can broadly accelerate translational research for neurodegenerative diseases.</p

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Groundwater estuaries of salt lakes: buried pools of endemic biodiversity on the western plateau, Australia

Subterranean or groundwater estuaries occur in porous and cavernous substrates where groundwater abuts the ocean. Like surface estuaries, they are strongly stratified, temporally and hydrochemically heterogeneous environments that support complex hydrogeochemical and biological processes and ecological communities. Here, we contend that groundwater estuaries also occur where groundwater flow approaches salt lakes and provide evidence in the context of groundwater (valley or phreatic) calcretes in palaeovalleys of the arid western plateau of Australia. The calcrete groundwater estuaries display marked and complex physico-chemical gradients along, across and through the groundwater flow path. From the first principles and the density differences between water bodies, we may expect the form and dynamics of the saltwater front to mimic that of marine estuaries but with the dynamic and temporal response to changing hydrology heavily dampened, and driven by the episodic groundwater recharge and lake filling typical of arid regions. The calcrete aquifers support diverse biological communities of obligate groundwater animals, largely endemic to a given calcrete body. These communities comprise both macro and microinvertebrates, predominantly a suite of crustacean higher taxa, and a great diversity of diving beetles (Dytiscidae) isolated in the calcrete aquifers between ca. 5 and 8 million years ago. © 2009 Springer Science+Business Media B.V.W. F. Humphreys, C. H. S. Watts, S. J. B. Cooper, R. Leij