745 research outputs found
A Novel Hypothesis for Thalidomide-Induced Limb Teratogenesis: Redox Misregulation of the NF-ÎșB Pathway
Several hypotheses have been proposed to explain the mechanisms of thalidomide teratogenesis, although none adequately accounts for the observed malformations and explains the basis for species specificity. Recent observations that thalidomide increases the production of free radicals and elicits oxidative stress, coupled with new insights into the redox regulation of nuclear transcription factors, lead to the suggestion that thalidomide may act through redox misregulation of the limb outgrowth pathways. Oxidative stress, as marked by glutathione depletion/oxidation and a shift in intracellular redox potential toward the positive, occurs preferentially in limbs of thalidomide-sensitive rabbits, but not in resistant rats. DNA binding of nuclear factor Îș-B (NF-ÎșB), a redox-sensitive transcription factor and key regulator of limb outgrowth, was shown to be significantly attenuated in rabbit limb cells and could be restored following the addition of a free radical spin-trapping agent, phenyl N-tert-butyl nitrone. The inability of NF-ÎșB to bind to its DNA promoter results in the failure of limb cells to express fibroblast growth factor (FGF)-10 and twist in the limb progress zone (PZ) mesenchyme, which in turn attenuates expression of FGF-8 in the apical ectodermal ridge (AER). Failure to establish an FGF-10/FGF-8 feedback loop between the PZ and AER results in the truncation of limb outgrowth. We hypothesize that species-selective alterations in redox microenvironment caused by free radical production from thalidomide results in attenuation of the NF-ÎșB-mediated gene expression that is responsible for limb outgrowth.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63400/1/152308604771978291.pd
Spatially Resolved Magnetic Field Structure in the Disk of a T Tauri Star
Magnetic fields in accretion disks play a dominant role during the star
formation process but have hitherto been observationally poorly constrained.
Field strengths have been inferred on T Tauri stars themselves and possibly in
the innermost part of the accretion disk, but the strength and morphology of
the field in the bulk of the disk have not been observed. Unresolved
measurements of polarized emission (arising from elongated dust grains aligned
perpendicular to the field) imply average fields aligned with the disks.
Theoretically, the fields are expected to be largely toroidal, poloidal, or a
mixture of the two, which imply different mechanisms for transporting angular
momentum in the disks of actively accreting young stars such as HL Tau. Here we
report resolved measurements of the polarized 1.25 mm continuum emission from
HL Tau's disk. The magnetic field on a scale of 80 AU is coincident with the
major axis (~210 AU diameter) of the disk. From this we conclude that the
magnetic field inside the disk at this scale cannot be dominated by a vertical
component, though a purely toroidal field does not fit the data well either.
The unexpected morphology suggests that the magnetic field's role for the
accretion of a T Tauri star is more complex than the current theoretical
understanding.Comment: Accepted for publication in Natur
Urban-rural inequities in the parental attitudes and beliefs towards Human papillomavirus infection, cervical cancer and HPV vaccine in Mysore, India
OBJECTIVE: The aim of this study was to compare the parental attitudes and beliefs about HPV, cervical cancer and HPV vaccine between urban and rural areas, India. DESIGN: Cross sectional SETTING: Mysore, India PARTICIPANTS: Parents of school going adolescent girls INTERVENTION: Parents completed a self-administered questionnaire MAIN OUTCOME MEASURES: : Attitudes and beliefs about HPV, cervical cancer and HPV vaccine RESULTS: A total of 1609 parents from urban (n=778) and rural (n=831) areas participated in this study. Majority of the parents had never heard about HPV (73.6%), did not know that their daughters could get an HPV infection (62.7%) or cervical cancer (64.1%) in the future, and believed that HPV vaccine was not effective (67.1%). Parents living in the urban area were more likely to believe that HPV infection (adjusted Odds Ratio [aOR] 2.69; 95%CI:1.43, 5.06) and cervical cancer (aOR 2.68; 95%CI:1.83, 3.91) could cause serious health problems than those living in the rural area. The odds of agreeing that HPV vaccination will make girls sexually active was lower among urban than rural parents (aOR 0.55; 95%CI:0.33, 0.94). There was no significant difference among parents in the urban and rural areas in their beliefs about susceptibility of their daughter to HPV infection or cervical cancer, and beliefs about the safety and ability of HPV vaccine to protect cervical cancer. CONCLUSIONS: Rural parents might be reluctant to recommend behaviors that can help prevent HPV infection and cervical cancer such as HPV vaccination for their daughters
Metabolic state alters economic decision making under risk in humans
Background: Animals' attitudes to risk are profoundly influenced by metabolic state (hunger and baseline energy stores). Specifically, animals often express a preference for risky (more variable) food sources when below a metabolic reference point (hungry), and safe (less variable) food sources when sated. Circulating hormones report the status of energy reserves and acute nutrient intake to widespread targets in the central nervous system that regulate feeding behaviour, including brain regions strongly implicated in risk and reward based decision-making in humans. Despite this, physiological influences per se have not been considered previously to influence economic decisions in humans. We hypothesised that baseline metabolic reserves and alterations in metabolic state would systematically modulate decision-making and financial risk-taking in humans.
Methodology/Principal Findings: We used a controlled feeding manipulation and assayed decision-making preferences across different metabolic states following a meal. To elicit risk-preference, we presented a sequence of 200 paired lotteries, subjects' task being to select their preferred option from each pair. We also measured prandial suppression of circulating acyl-ghrelin (a centrally-acting orexigenic hormone signalling acute nutrient intake), and circulating leptin levels (providing an assay of energy reserves). We show both immediate and delayed effects on risky decision-making following a meal, and that these changes correlate with an individual's baseline leptin and changes in acyl-ghrelin levels respectively.
Conclusions/Significance:
We show that human risk preferences are exquisitely sensitive to current metabolic state, in a direction consistent with ecological models of feeding behaviour but not predicted by normative economic theory. These substantive effects of state changes on economic decisions perhaps reflect shared evolutionarily conserved neurobiological mechanisms. We suggest that this sensitivity in human risk-preference to current metabolic state has significant implications for both real-world economic transactions and for aberrant decision-making in eating disorders and obesity
Impact of the "Tobacco control law" on exposure to environmental tobacco smoke in Spain
<p>Abstract</p> <p>Background</p> <p>The initial evaluations of the introduction of legislation that regulates smoking in enclosed public places in European countries, describe an important effect in the control of exposure to environmental tobacco smoke. However, the evidence is still limited. The objective of this study is to estimate the short-term effects of the comprehensive "Tobacco control law" introduced in Spain on January 2006, which includes a total ban of smoking in workplaces and a partial limitation of smoking in bars and restaurants.</p> <p>Methods</p> <p>Cross-sectional, population-based study. The self-reported exposure to environmental tobacco smoke at home, at work, in bars and restaurants of the population aged 18 to 64 years in the Madrid Region during a period prior to the law (October and November 2005; n = 1750) was compared to that of the period immediately after the law came into force (January-July 2006; n = 1252). Adjusted odds ratios (OR) were calculated using logistic regression models.</p> <p>Results</p> <p>Passive exposure to tobacco smoke at home has hardly changed. However, at indoor workplaces there has been a considerable reduction: after the law came into force the OR for daily exposure > 0â3 hours versus non-exposure was 0.11 (95% CI: 0.07 to 0.17) and for more than 3 hours, 0.12 (95% CI: 0.09 to 0.18). For fairly high exposure in bars and restaurants versus non-exposure, the OR in the former was 0.30 (95% CI: 0.20 to 0.44) and in the latter was 0.24 (95% CI: 0.18 to 0.32); for very high exposure versus non-exposure they were 0.16 (95% CI: 0.10 to 0.24) and 0.11 (95% CI: 0.07 to 0.19), respectively. These results were similar for the smoking and non-smoking populations.</p> <p>Conclusion</p> <p>A considerable reduction in exposure to environmental tobacco smoke in the workplace and, to a lesser extent, in bars and restaurants, is related to the implementation of the "Tobacco control law". Although only initial figures, these results already demonstrate the effectiveness of strategies that establish control measures to guarantee smoke-free places.</p
Association of bovine leptin polymorphisms with energy output and energy storage traits in progeny tested Holstein-Friesian dairy cattle sires
peer-reviewedBackground: Leptin modulates appetite, energy expenditure and the reproductive axis by signalling via its receptor the status of body energy stores to the brain. The present study aimed to quantify the associations between 10 novel and known single nucleotide polymorphisms in genes coding for leptin and leptin receptor with performance traits in 848 Holstein-Friesian sires, estimated from performance of up to 43,117 daughter-parity records per sire. Results: All single nucleotide polymorphisms were segregating in this sample population and none deviated (P > 0.05) from Hardy-Weinberg equilibrium. Complete linkage disequilibrium existed between the novel polymorphism LEP-1609, and the previously identified polymorphisms LEP-1457 and LEP-580. LEP-2470 associated (P < 0.05) with milk protein concentration and calf perinatal mortality. It had a tendency to associate with milk yield (P < 0.1). The G allele of LEP-1238 was associated (P < 0.05) with reduced milk fat concentration, reduced milk protein concentration, longer gestation length and tended to associate (P < 0.1) with an increase in calving difficulty, calf perinatal mortality and somatic cells in the milk. LEP-963 exhibited an association (P < 0.05) with milk fat concentration, milk protein concentration, calving difficulty and gestation length. It also tended to associate with milk yield (P < 0.1). The R25C SNP associated (P < 0.05) with milk fat concentration, milk protein concentration, calving difficulty and length of gestation. The T allele of the Y7F SNP significantly associated with reduced angularity (P < 0.01) and reduced milk protein yield (P < 0.05). There was also a tendency (P < 0.1) for Y7F to associate with increased body condition score, reduced milk yield and shorter gestation (P < 0.1). A80V associated with reduced survival in the herd (P < 0.05). Conclusions Several leptin polymorphisms (LEP-2470, LEP-1238, LEP-963, Y7F and R25C) associated with the energetically expensive process of lactogenesis. Only SNP Y7F associated with energy storage. Associations were also observed between leptin polymorphisms and calving difficulty, gestation length and calf perinatal mortality. The lack of an association between the leptin variants investigated with calving interval in this large data set would question the potential importance of these leptin variants, or indeed leptin, in selection for improved fertility in the Holstein-Friesian dairy cow.Department of Agriculture, Food and Fisheries, Ireland - Research Stimulus Fund (RSF-06-0353; RSF-06-0409); Irish Dairy Research Trust; Teagasc Walsh Fellowshi
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Observational constraints on atmospheric and oceanic cross-equatorial heat transports: revisiting the precipitation asymmetry problem in climate models
Satellite based top-of-atmosphere (TOA) and surface radiation budget observations are combined with mass corrected vertically integrated atmospheric energy divergence and tendency from reanalysis to infer the regional distribution of the TOA, atmospheric and surface energy budget terms over the globe. Hemispheric contrasts in the energy budget terms are used to determine the radiative and combined sensible and latent heat contributions to the cross-equatorial heat transports in the atmosphere (AHT_EQ) and ocean (OHT_EQ). The contrast in net atmospheric radiation implies an AHT_EQ from the northern hemisphere (NH) to the southern hemisphere (SH) (0.75 PW), while the hemispheric difference in sensible and latent heat implies an AHT_EQ in the opposite direction (0.51 PW), resulting in a net NH to SH AHT_EQ (0.24 PW). At the surface, the hemispheric contrast in the radiative component (0.95 PW) dominates, implying a 0.44 PW SH to NH OHT_EQ. Coupled model intercomparison project phase 5 (CMIP5) models with excessive net downward surface radiation and surface-to-atmosphere sensible and latent heat transport in the SH relative to the NH exhibit anomalous northward AHT_EQ and overestimate SH tropical precipitation. The hemispheric bias in net surface radiative flux is due to too much longwave surface radiative cooling in the NH tropics in both clear and all-sky conditions and excessive shortwave surface radiation in the SH subtropics and extratropics due to an underestimation in reflection by clouds
Photonic quantum technologies
The first quantum technology, which harnesses uniquely quantum mechanical
effects for its core operation, has arrived in the form of commercially
available quantum key distribution systems that achieve enhanced security by
encoding information in photons such that information gained by an eavesdropper
can be detected. Anticipated future quantum technologies include large-scale
secure networks, enhanced measurement and lithography, and quantum information
processors, promising exponentially greater computation power for particular
tasks. Photonics is destined for a central role in such technologies owing to
the need for high-speed transmission and the outstanding low-noise properties
of photons. These technologies may use single photons or quantum states of
bright laser beams, or both, and will undoubtably apply and drive
state-of-the-art developments in photonics
Missense and nonsense mutations in melanocortin 1 receptor (MC1R) gene of different goat breeds: association with red and black coat colour phenotypes but with unexpected evidences
<p>Abstract</p> <p>Background</p> <p><it>Agouti </it>and <it>Extension </it>loci control the relative amount of eumelanin and pheomelanin production in melanocytes that, in turn, affects pigmentation of skin and hair. The <it>Extension </it>locus encodes the melanocortin 1 receptor (MC1R) whose permanent activation, caused by functional mutations, results in black coat colour, whereas other inactivating mutations cause red coat colour in different mammals.</p> <p>Results</p> <p>The whole coding region of the <it>MC1R </it>gene was sequenced in goats of six different breeds showing different coat colours (Girgentana, white cream with usually small red spots in the face; Maltese, white with black cheeks and ears; Derivata di Siria, solid red; Murciano-Granadina, solid black or solid brown; Camosciata delle Alpi, brown with black stripes; Saanen, white; F<sub>1 </sub>goats and the parental animals). Five single nucleotide polymorphisms (SNPs) were identified: one nonsense mutation (p.Q225X), three missense mutations (p.A81V, p.F250V, and p.C267W), and one silent mutation. The stop codon at position 225 should cause the production of a shorter MC1R protein whose functionality may be altered. These SNPs were investigated in a larger sample of animals belonging to the six breeds. The Girgentana breed was almost fixed for the p.225X allele. However, there was not complete association between the presence of red spots in the face and the presence of this allele in homozygous condition. The same allele was identified in the Derivata di Siria breed. However, its frequency was only 33%, despite the fact that these animals are completely red. The p.267W allele was present in all Murciano-Granadina black goats, whereas it was never identified in the brown ones. Moreover, the same substitution was present in almost all Maltese goats providing evidence of association between this mutation and black coat colour.</p> <p>Conclusion</p> <p>According to the results obtained in the investigated goat breeds, <it>MC1R </it>mutations may determine eumelanic and pheomelanic phenotypes. However, they are probably not the only factors. In particular, the surprising not complete association of the nonsense mutation (p.Q225X) with red coat colour raises a few hypotheses on the determination of pheomelanic phenotypes in goats that should be further investigated.</p
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Systems analyses reveal the resilience of Escherichia coli physiology during accumulation and export of the nonnative organic acid citramalate
© 2019 Webb et al. Productivity of bacterial cell factories is frequently compromised by stresses imposed by recombinant protein synthesis and carbon-to-product conversion, but little is known about these bioprocesses at a systems level. Production of the unnatural metabolite citramalate in Escherichia coli requires the expression of a single gene coding for citramalate synthase. Multiomic analyses of a fermentation producing 25 g liter1 citramalate were undertaken to uncover the reasons for its productivity. Metabolite, transcript, protein, and lipid profiles of high-cell-density, fed-batch fermentations of E. coli expressing either citramalate synthase or an inactivated enzyme were similar. Both fermentations showed downregulation of flagellar genes and upregulation of chaperones IbpA and IbpB, indicating that these responses were due to recombinant protein synthesis and not citramalate production. Citramalate production did not perturb metabolite pools, except for an increased intracellular pyruvate pool. Gene expression changes in response to citramalate were limited; none of the general stress response regulons were activated. Modeling of transcription factor activities suggested that citramalate invoked a GadW-mediated acid response, and changes in GadY and RprA regulatory small RNA (sRNA) expression supported this. Although changes in membrane lipid composition were observed, none were unique to citramalate production. This systems analysis of the citramalate fermentation shows that E. coli has capacity to readily adjust to the redirection of resources toward recombinant protein and citramalate production, suggesting that it is an excellent chassis choice for manufacturing organic acids. IMPORTANCE Citramalate is an attractive biotechnology target because it is a precursor of methylmethacrylate, which is used to manufacture Perspex and other high-value products. Engineered E. coli strains are able to produce high titers of citramalate, despite having to express a foreign enzyme and tolerate the presence of a nonnative biochemical. A systems analysis of the citramalate fermentation was undertaken to uncover the reasons underpinning its productivity. This showed that E. coli readily adjusts to the redirection of metabolic resources toward recombinant protein and citramalate production and suggests that E. coli is an excellent chassis for manufacturing similar small, polar, foreign molecules.We thank the Biotechnology and Biological Sciences Research Council UK and InnovateUK for funding (Industrial Biotechnology Catalyst BB/N01040X/1) and the Centre of Excellence in Mass Spectrometry funded by Science City York (Yorkshire Forward, EP/K039660/1, EP/M028127/1)
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