1,063 research outputs found
Toward Fulfilling the Promise of Molecular Medicine in Fragile X
Fragile X syndrome (FXS) is the most common inherited form of mental retardation and a leading known cause of autism. It is caused by loss of expression of the fragile X mental retardation protein (FMRP), an RNA-binding protein that negatively regulates protein synthesis. In neurons, multiple lines of evidence suggest that protein synthesis at synapses is triggered by activation of group 1 metabotropic glutamate receptors (Gp1 mGluRs) and that many functional consequences of activating these receptors are altered in the absence of FMRP. These observations have led to the theory that exaggerated protein synthesis downstream of Gp1 mGluRs is a core pathogenic mechanism in FXS. This excess can be corrected by reducing signaling by Gp1 mGluRs, and numerous studies have shown that inhibition of mGluR5, in particular, can ameliorate multiple mutant phenotypes in animal models of FXS. Clinical trials based on this therapeutic strategy are currently under way. FXS is therefore poised to be the first neurobehavioral disorder in which corrective treatments have been developed from the bottom up: from gene identification to pathophysiology in animals to novel therapeutics in humans. The insights gained from FXS and other autism-related single-gene disorders may also assist in identifying molecular mechanisms and potential treatment approaches for idiopathic autism.Eunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.)National Institute of Mental Health (U.S.)FRAXA Research Foundatio
Possible Role of Horizontal Gene Transfer in the Colonization of Sea Ice by Algae
Diatoms and other algae not only survive, but thrive in sea ice. Among sea ice diatoms, all species examined so far produce ice-binding proteins (IBPs), whereas no such proteins are found in non-ice-associated diatoms, which strongly suggests that IBPs are essential for survival in ice. The restricted occurrence also raises the question of how the IBP genes were acquired. Proteins with similar sequences and ice-binding activities are produced by ice-associated bacteria, and so it has previously been speculated that the genes were acquired by horizontal transfer (HGT) from bacteria. Here we report several new IBP sequences from three types of ice algae, which together with previously determined sequences reveal a phylogeny that is completely incongruent with algal phylogeny, and that can be most easily explained by HGT. HGT is also supported by the finding that the closest matches to the algal IBP genes are all bacterial genes and that the algal IBP genes lack introns. We also describe a highly freeze-tolerant bacterium from the bottom layer of Antarctic sea ice that produces an IBP with 47% amino acid identity to a diatom IBP from the same layer, demonstrating at least an opportunity for gene transfer. Together, these results suggest that the success of diatoms and other algae in sea ice can be at least partly attributed to their acquisition of prokaryotic IBP genes
Evidence for Two Modes of Synergistic Induction of Apoptosis by Mapatumumab and Oxaliplatin in Combination with Hyperthermia in Human Colon Cancer Cells
Colorectal cancer is the third leading cause of cancer-related mortality in the world-- the main cause of death from colorectal cancer is hepatic metastases, which can be treated with isolated hepatic perfusion (IHP). Searching for the most clinically relevant approaches for treating colorectal metastatic disease by isolated hepatic perfusion (IHP), we developed the application of oxaliplatin concomitantly with hyperthermia and humanized death receptor 4 (DR4) antibody mapatumumab (Mapa), and investigated the molecular mechanisms of this multimodality treatment in human colon cancer cell lines CX-1 and HCT116 as well as human colon cancer stem cells Tu-12, Tu-21 and Tu-22. We showed here, in this study, that the synergistic effect of the multimodality treatment-induced apoptosis was caspase dependent and activated death signaling via both the extrinsic apoptotic pathway and the intrinsic pathway. Death signaling was activated by c-Jun N-terminal kinase (JNK) signaling which led to Bcl-xL phosphorylation at serine 62, decreasing the anti-apoptotic activity of Bcl-xL, which contributed to the intrinsic pathway. The downregulation of cellular FLICE inhibitory protein long isoform (c-FLIPL) in the extrinsic pathway was accomplished through ubiquitination at lysine residue (K) 195 and protein synthesis inhibition. Overexpression of c-FLIPL mutant (K195R) and Bcl-xL mutant (S62A) completely abrogated the synergistic effect. The successful outcome of this study supports the application of multimodality strategy to patients with colorectal hepatic metastases who fail to respond to standard chemoradiotherapy that predominantly targets the mitochondrial apoptotic pathway. © 2013 Song et al
Genetic parameters for growth, wood density and pulp yield in Eucalyptus globulus
Genetic variation and co-variation among the key
pulpwood selection traits for Eucalyptus globulus were
estimated for a range of sites in Portugal, with the aim of
improving genetic parameters used to predict breeding
values and correlated response to selection. The trials
comprised clonally replicated full-sib families (eight trials)
and unrelated clones (17 trials), and exhibited varying
levels of pedigree connectivity. The traits studied were stem
diameter at breast height, Pilodyn penetration (an indirect
measure of wood basic density) and near infrared reflectance
predicted pulp yield. Univariate and multivariate
linear mixed models were fitted within and across sites, and estimates of additive genetic, total genetic, environmental
and phenotypic variances and covariances were obtained.
All traits studied exhibited significant levels of additive
genetic variation. The average estimated within-site narrowsense
heritability was 0.19±0.03 for diameter and 0.29±
0.03 for Pilodyn penetration, and the pooled estimate for
predicted pulp yield was 0.42±0.14. When they could be
tested, dominance and epistatic effects were generally not
statistically significant, although broad-sense heritability
estimates were slightly higher than narrow-sense heritability
estimates. Averaged across trials, positive additive
(0.64±0.08), total genetic (0.58±0.04), environmental
(0.38±0.03) and phenotypic (0.43±0.02) correlation estimates
were consistently obtained between diameter and
Pilodyn penetration. This data argues for at least some form
of pleiotropic relationship between these two traits and that
selection for fast growth will adversely affect wood density
in this population. Estimates of the across-site genetic
correlations for diameter and Pilodyn penetration were
high, indicating that the genotype by environment interaction
is low across the range of sites tested. This result
supports the use of single aggregated selection criteria for
growth and wood density across planting environments in
Portugal, as opposed to having to select for performance in
different environment
Comparison of two different models for pile thermal response test interpretation
Thermal response tests (TRTs) are regularly used to characterise the thermal resistance of borehole heat exchangers and to assess the thermal conductivity of the surrounding ground. It is becoming common to apply the same in situ testing technique to pile heat exchangers, despite international guidance suggesting that TRTs should be limited to hole diameters of 152 mm (6 in.). This size restriction arises from the increased thermal inertia of larger diameter heat exchangers, which invalidates the assumption of a steady state within the concrete needed to interpret the test data by traditional line source analysis techniques. However, new methods of analysis for pile heat exchangers have recently been developed that take account of the transient behaviour of the pile concrete. This paper applies these new methods to data from a multi-stage TRT conducted on a small diameter test pile. The thermal conductivity and thermal resistance determined using this method are then compared with those from traditional analytical approaches based on a line source analysis. Differences between the approaches are discussed, along with the observation that the thermal resistance may not be constant over the different test stages
Makerere University College of Health Sciencesâ role in addressing challenges in health service provision at Mulago National Referral Hospital
<p>Abstract</p> <p>Background</p> <p>Mulago National Referral Hospital (MNRH), Ugandaâs primary tertiary and teaching hospital, and Makerere University College of Health Sciences (MakCHS) have a close collaborative relationship. MakCHS students complete clinical rotations at MNRH, and MakCHS faculty partner with Mulago staff in clinical care and research. In 2009, as part of a strategic planning process, MakCHS undertook a qualitative study to examine care and service provision at MNRH, identify challenges, gaps, and solutions, and explore how MakCHS could contribute to improving care and service delivery at MNRH.</p> <p>Methods</p> <p>Key informant interviews (n=23) and focus group discussions (n=7) were conducted with nurses, doctors, administrators, clinical officers and other key stakeholders. Interviews and focus groups were tape recorded and transcribed verbatim, and findings were analyzed through collaborative thematic analysis.</p> <p>Results</p> <p>Challenges to care and service delivery at MNRH included resource constraints (staff, space, equipment, and supplies), staff inadequacies (knowledge, motivation, and professionalism), overcrowding, a poorly functioning referral system, limited quality assurance, and a cumbersome procurement system. There were also insufficiencies in the teaching of professionalism and communication skills to students, and patient care challenges that included lack of access to specialized services, risk of infections, and inappropriate medications.</p> <p>Suggestions for how MakCHS could contribute to addressing these challenges included strengthening referral systems and peripheral health center capacity, and establishing quality assurance mechanisms. The College could also strengthen the teaching of professionalism, communication and leadership skills to students, and monitor student training and develop courses that contribute to continuous professional development. Additionally, the College could provide in-service education for providers on professionalism, communication skills, strategies that promote evidence-based practice and managerial leadership skills.</p> <p>Conclusions</p> <p>Although there are numerous barriers to delivery of quality health services at MNRH, many barriers could be addressed by strengthening the relationship between the Hospital and MakCHS. Strategic partnerships and creative use of existing resources, both human and financial, could improve the quality of care and service delivery at MNRH. Improving services and providing more skills training could better prepare MakCHS graduates for leadership roles in other health care facilities, ultimately improving health outcomes throughout Uganda.</p
Autism as a disorder of neural information processing: directions for research and targets for therapy
The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself
The Impact of Oxygen on Metabolic Evolution: A Chemoinformatic Investigation
The appearance of planetary oxygen likely transformed the chemical and biochemical makeup of life and probably triggered episodes of organismal diversification. Here we use chemoinformatic methods to explore the impact of the rise of oxygen on metabolic evolution. We undertake a comprehensive comparative analysis of structures, chemical properties and chemical reactions of anaerobic and aerobic metabolites. The results indicate that aerobic metabolism has expanded the structural and chemical space of metabolites considerably, including the appearance of 130 novel molecular scaffolds. The molecular functions of these metabolites are mainly associated with derived aspects of cellular life, such as signal transfer, defense against biotic factors, and protection of organisms from oxidation. Moreover, aerobic metabolites are more hydrophobic and rigid than anaerobic compounds, suggesting they are better fit to modulate membrane functions and to serve as transmembrane signaling factors. Since higher organisms depend largely on sophisticated membrane-enabled functions and intercellular signaling systems, the metabolic developments brought about by oxygen benefit the diversity of cellular makeup and the complexity of cellular organization as well. These findings enhance our understanding of the molecular link between oxygen and evolution. They also show the significance of chemoinformatics in addressing basic biological questions
Genetic characterisation of farmed rainbow trout in Norway: intra- and inter-strain variation reveals potential for identification of escapees
<p>Abstract</p> <p>Background</p> <p>The rainbow trout (<it>Oncorhynchus mykiss</it>) is one of the most important aquaculture species in the world, and Norway is one of the largest producers. The present study was initiated in response to a request from the Norwegian police authority to identify the farm of origin for 35 escaped rainbow trout captured in a fjord. Eleven samples, each consisting of approximately 47 fish, were collected from the three farms operating in the fjord where the escapees were captured. In order to gain a better general understanding of the genetic structure of rainbow trout strains used in Norwegian aquaculture, seven samples (47 fish per sample) were collected from six farms located outside the region where the escapees were captured. All samples, including the escapees, were genotyped with 12 microsatellite loci.</p> <p>Results</p> <p>All samples displayed considerable genetic variability at all loci (mean number of alleles per locus per sample ranged from 5.4â8.6). Variable degrees of genetic differentiation were observed among the samples, with pair-wise <it>F</it><sub>ST </sub>values ranging from 0â0.127. Self-assignment tests conducted among the samples collected from farms outside the fjord where the escapees were observed gave an overall correct assignment of 82.5%, demonstrating potential for genetic identification of escapees. In the "real life" assignment of the 35 captured escapees, all were excluded from two of the samples included as controls in the analysis, and 26 were excluded from the third control sample. In contrast, only 1 of the escapees was excluded from the 11 pooled samples collected on the 3 farms operating in the fjord.</p> <p>Conclusion</p> <p>Considerable genetic variation exists within and among rainbow trout strains farmed in Norway. Together with modern statistical methods, this will provide commercial operators with a tool to monitor breeding and fish movements, and management authorities with the ability to identify the source of escapees. The data generated in this study were used by the Norwegian police to initiate an investigation of the company operating the three farms in the fjord where escapees were observed.</p
Observation of associated near-side and away-side long-range correlations in âsNN=5.02ââTeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (ÎÏ) and pseudorapidity (Îη) are measured in âsNN=5.02ââTeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1ââÎŒb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Îη|<5) ânear-sideâ (ÎÏâŒ0) correlation that grows rapidly with increasing ÎŁETPb. A long-range âaway-sideâ (ÎÏâŒÏ) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Îη and ÎÏ) and ÎŁETPb dependence. The resultant ÎÏ correlation is approximately symmetric about Ï/2, and is consistent with a dominant cosâĄ2ÎÏ modulation for all ÎŁETPb ranges and particle pT
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