A Cryogenic Silicon Interferometer for Gravitational-wave Detection

The detection of gravitational waves from compact binary mergers by LIGO has opened the era of gravitational wave astronomy, revealing a previously hidden side of the cosmos. To maximize the reach of the existing LIGO observatory facilities, we have designed a new instrument that will have 5 times the range of Advanced LIGO, or greater than 100 times the event rate. Observations with this new instrument will make possible dramatic steps toward understanding the physics of the nearby universe, as well as observing the universe out to cosmological distances by the detection of binary black hole coalescences. This article presents the instrument design and a quantitative analysis of the anticipated noise floor

Variability in gene expression underlies incomplete penetrance

The phenotypic differences between individual organisms can often be ascribed to underlying genetic and environmental variation. However, even genetically identical organisms in homogeneous environments vary, indicating that randomness in developmental processes such as gene expression may also generate diversity. To examine the consequences of gene expression variability in multicellular organisms, we studied intestinal specification in the nematode Caenorhabditis elegans in which wild-type cell fate is invariant and controlled by a small transcriptional network. Mutations in elements of this network can have indeterminate effects: some mutant embryos fail to develop intestinal cells, whereas others produce intestinal precursors. By counting transcripts of the genes in this network in individual embryos, we show that the expression of an otherwise redundant gene becomes highly variable in the mutants and that this variation is subjected to a threshold, producing an ON/OFF expression pattern of the master regulatory gene of intestinal differentiation. Our results demonstrate that mutations in developmental networks can expose otherwise buffered stochastic variability in gene expression, leading to pronounced phenotypic variation.National Institutes of Health (U.S.). Pioneer AwardMathematical Sciences Postdoctoral Research Fellowships (DMS-0603392)National Institutes of Health (U.S.). Ruth L. Kirschstein National Research Service Award (5F32GM080966

C. elegans ATAD-3 Is Essential for Mitochondrial Activity and Development

Contains fulltext : 80701.pdf (publisher's version ) (Open Access)BACKGROUND: Mammalian ATAD3 is a mitochondrial protein, which is thought to play an important role in nucleoid organization. However, its exact function is still unresolved. RESULTS: Here, we characterize the Caenorhabditis elegans (C. elegans) ATAD3 homologue (ATAD-3) and investigate its importance for mitochondrial function and development. We show that ATAD-3 is highly conserved among different species and RNA mediated interference against atad-3 causes severe defects, characterized by early larval arrest, gonadal dysfunction and embryonic lethality. Investigation of mitochondrial physiology revealed a disturbance in organellar structure while biogenesis and function, as indicated by complex I and citrate synthase activities, appeared to be unaltered according to the developmental stage. Nevertheless, we observed very low complex I and citrate synthase activities in L1 larvae populations in comparison to higher larval and adult stages. Our findings indicate that atad-3(RNAi) animals arrest at developmental stages with low mitochondrial activity. In addition, a reduced intestinal fat storage and low lysosomal content after depletion of ATAD-3 suggests a central role of this protein for metabolic activity. CONCLUSIONS: In summary, our data clearly indicate that ATAD-3 is essential for C. elegans development in vivo. Moreover, our results suggest that the protein is important for the upregulation of mitochondrial activity during the transition to higher larval stages

Computerised interpretation of fetal heart rate during labour (INFANT): a randomised controlled trial

Background. Continuous electronic fetal heart-rate monitoring is widely used during labour, and computerised interpretation could increase its usefulness. We aimed to establish whether the addition of decision-support software to assist in the interpretation of cardiotocographs affected the number of poor neonatal outcomes. Methods. In this unmasked randomised controlled trial, we recruited women in labour aged 16 years or older having continuous electronic fetal monitoring, with a singleton or twin pregnancy, and at 35 weeks’ gestation or more at 24 maternity units in the UK and Ireland. They were randomly assigned (1:1) to decision support with the INFANT system or no decision support via a computer-generated stratified block randomisation schedule. The primary outcomes were poor neonatal outcome (intrapartum stillbirth or early neonatal death excluding lethal congenital anomalies, or neonatal encephalopathy, admission to the neonatal unit within 24 h for ≥48 h with evidence of feeding difficulties, respiratory illness, or encephalopathy with evidence of compromise at birth), and developmental assessment at age 2 years in a subset of surviving children. Analyses were done by intention to treat. This trial is completed and is registered with the ISRCTN Registry, number 98680152. Findings. Between Jan 6, 2010, and Aug 31, 2013, 47062 women were randomly assigned (23515 in the decision-support group and 23547 in the no-decision-support group) and 46042 were analysed (22987 in the decision-support group and 23055 in the no-decision-support group). We noted no difference in the incidence of poor neonatal outcome between the groups—172 (0·7%) babies in the decision-support group compared with 171 (0·7%) babies in the no-decision-support group (adjusted risk ratio 1·01, 95% CI 0·82–1·25). At 2 years, no significant differences were noted in terms of developmental assessment. Interpretation. Use of computerised interpretation of cardiotocographs in women who have continuous electronic fetal monitoring in labour does not improve clinical outcomes for mothers or babies

An Integrated Strategy to Study Muscle Development and Myofilament Structure in Caenorhabditis elegans

A crucial step in the development of muscle cells in all metazoan animals is the assembly and anchorage of the sarcomere, the essential repeat unit responsible for muscle contraction. In Caenorhabditis elegans, many of the critical proteins involved in this process have been uncovered through mutational screens focusing on uncoordinated movement and embryonic arrest phenotypes. We propose that additional sarcomeric proteins exist for which there is a less severe, or entirely different, mutant phenotype produced in their absence. We have used Serial Analysis of Gene Expression (SAGE) to generate a comprehensive profile of late embryonic muscle gene expression. We generated two replicate long SAGE libraries for sorted embryonic muscle cells, identifying 7,974 protein-coding genes. A refined list of 3,577 genes expressed in muscle cells was compiled from the overlap between our SAGE data and available microarray data. Using the genes in our refined list, we have performed two separate RNA interference (RNAi) screens to identify novel genes that play a role in sarcomere assembly and/or maintenance in either embryonic or adult muscle. To identify muscle defects in embryos, we screened specifically for the Pat embryonic arrest phenotype. To visualize muscle defects in adult animals, we fed dsRNA to worms producing a GFP-tagged myosin protein, thus allowing us to analyze their myofilament organization under gene knockdown conditions using fluorescence microscopy. By eliminating or severely reducing the expression of 3,300 genes using RNAi, we identified 122 genes necessary for proper myofilament organization, 108 of which are genes without a previously characterized role in muscle. Many of the genes affecting sarcomere integrity have human homologs for which little or nothing is known

Genome of <i>Leptomonas pyrrhocoris</i>:a high-quality reference for monoxenous trypanosomatids and new insights into evolution of <i>Leishmania</i>

Many high-quality genomes are available for dixenous (two hosts) trypanosomatid species of the genera Trypanosoma, Leishmania, and Phytomonas, but only fragmentary information is available for monoxenous (single-host) trypanosomatids. In trypanosomatids, monoxeny is ancestral to dixeny, thus it is anticipated that the genome sequences of the key monoxenous parasites will be instrumental for both understanding the origin of parasitism and the evolution of dixeny. Here, we present a high-quality genome for Leptomonas pyrrhocoris, which is closely related to the dixenous genus Leishmania. The L. pyrrhocoris genome (30.4 Mbp in 60 scaffolds) encodes 10,148 genes. Using the L. pyrrhocoris genome, we pinpointed genes gained in Leishmania. Among those genes, 20 genes with unknown function had expression patterns in the Leishmania mexicana life cycle suggesting their involvement in virulence. By combining differential expression data for L. mexicana, L. major and Leptomonas seymouri, we have identified several additional proteins potentially involved in virulence, including SpoU methylase and U3 small nucleolar ribonucleoprotein IMP3. The population genetics of L. pyrrhocoris was also addressed by sequencing thirteen strains of different geographic origin, allowing the identification of 1,318 genes under positive selection. This set of genes was significantly enriched in components of the cytoskeleton and the flagellum

Chemical and antimicrobial profiling of propolis from different regions within Libya.

Extracts from twelve samples of propolis collected from different regions of Libya were tested for their activity against Trypanosoma brucei, Leishmania donovani, Plasmodium falciparum, Crithidia fasciculata and Mycobacterium marinum and the cytotoxicity of the extracts was tested against mammalian cells. All the extracts were active to some degree against all of the protozoa and the mycobacterium, exhibiting a range of EC50 values between 1.65 and 53.6 μg/ml. The toxicity against mammalian cell lines was only moderate; the most active extract against the protozoan species, P2, displayed an IC50 value of 53.2 μg/ml. The extracts were profiled by using liquid chromatography coupled to high resolution mass spectrometry. The data sets were extracted using m/z Mine and the accurate masses of the features extracted were searched against the Dictionary of Natural Products (DNP). A principal component analysis (PCA) model was constructed which, in combination with hierarchical cluster analysis (HCA), divided the samples into five groups. The outlying groups had different sets of dominant compounds in the extracts, which could be characterised by their elemental composition. Orthogonal partial least squares (OPLS) analysis was used to link the activity of each extract against the different micro-organisms to particular components in the extracts

Cellular uptake, cytotoxicity and DNA-binding studies of the novel imidazoacridinone antineoplastic agent C1311

C1311 is a novel therapeutic agent with potent activity against experimental colorectal cancer that has been selected for entry into clinical trial. The compound has previously been shown to have DNA-binding properties and to inhibit the catalytic activity of topoisomerase II. In this study, cellular uptake and mechanisms by which C1311 interacts with DNA and exerts cytotoxic effects in intact colon carcinoma cells were investigated. The HT29 colon cancer cell line was chosen to follow cellular distribution of C1311 over a time course of 24 h at drug concentrations that just inhibited cell proliferation by 50% or 100%. Nuclear uptake of C1311 and co-localization with lysosomal or mitochondrial dyes was examined by fluorescence microscopy and effects on these cellular compartments were determined by measurement of acid phosphatase levels, rhodamine 123 release or DNA-binding behaviour. The strength and mode of DNA binding was established by thermal melting stabilization, direct titration and viscometric studies of host duplex length. The onset of apoptosis was followed using a TUNEL assay and DNA-fragmentation to determine a causal relationship of cell death. Growth inhibition of HT29 cells by C1311 was concomitant with rapid drug accumulation in nuclei and in this context we showed that the compound binds to duplex DNA by intercalation, with likely A/T sequence-preferential binding. Drug uptake was also seen in lysosomes, leading to lysosomal rupture and a marked increase of acid phosphatase activity 8 h after exposure to C1311 concentrations that effect total growth inhibition. Moreover, at these concentrations lysosomal swelling and breakdown preceded apoptosis, which was not evident up to 24 h after exposure to drug. Thus, the lysosomotropic effect of C1311 appears to be a novel feature of this anticancer agent. As it is unlikely that C1311-induced DNA damage alone would be sufficient for cytotoxic activity, lysosomal rupture may be a critical component for therapeutic efficacy. © 1999 Cancer Research Campaig

Disparity Changes in 370 Ma Devonian Fossils: The Signature of Ecological Dynamics?

Early periods in Earth's history have seen a progressive increase in complexity of the ecosystems, but also dramatic crises decimating the biosphere. Such patterns are usually considered as large-scale changes among supra-specific groups, including morphological novelties, radiation, and extinctions. Nevertheless, in the same time, each species evolved by the way of micro-evolutionary processes, extended over millions of years into the evolution of lineages. How these two evolutionary scales interacted is a challenging issue because this requires bridging a gap between scales of observation and processes. The present study aims at transferring a typical macro-evolutionary approach, namely disparity analysis, to the study of fine-scale evolutionary variations in order to decipher what processes actually drove the dynamics of diversity at a micro-evolutionary level. The Late Frasnian to Late Famennian period was selected because it is punctuated by two major macro-evolutionary crises, as well as a progressive diversification of marine ecosystem. Disparity was estimated through this period on conodonts, tooth-like fossil remains of small eel-like predators that were part of the nektonic fauna. The study was focused on the emblematic genus of the period, Palmatolepis. Strikingly, both crises affected an already impoverished Palmatolepis disparity, increasing risks of random extinction. The major disparity signal rather emerged as a cycle of increase and decrease in disparity during the inter-crises period. The diversification shortly followed the first crisis and might correspond to an opportunistic occupation of empty ecological niche. The subsequent oriented shrinking in the morphospace occupation suggests that the ecological space available to Palmatolepis decreased through time, due to a combination of factors: deteriorating climate, expansion of competitors and predators. Disparity changes of Palmatolepis thus reflect changes in the structure of the ecological space itself, which was prone to evolve during this ancient period where modern ecosystems were progressively shaped