77 research outputs found
Comparison of Nitrofen Uptake via Water and Food and its Distribution in Tissue of Common Carp, Cyprinus carpio L.
Carp (Cyprinus carpio L.) were exposed to nitrofen (NIP) by different routes (via water or food) to compare bioaccumulation parameters and tissue distribution. The bioconcentration factor of NIP was 5,100, and the lipid-corrected biomagnification factor was 0.137. Growth-corrected elimination half lives were 2.1–3.0 days via aqueous exposure and 2.7–2.9 days via dietary exposure. From either uptake route, the tissue distribution of NIP was highest in the head, followed by muscle, viscera, dermis, digestive tract and hepatopancreas, which was highly correlated with the tissue lipid content. We conclude that the uptake route has no influence on tissue distribution of NIP and that the accumulation potential in tissues depends on the lipid content
The origin of large molecules in primordial autocatalytic reaction networks
Large molecules such as proteins and nucleic acids are crucial for life, yet
their primordial origin remains a major puzzle. The production of large
molecules, as we know it today, requires good catalysts, and the only good
catalysts we know that can accomplish this task consist of large molecules.
Thus the origin of large molecules is a chicken and egg problem in chemistry.
Here we present a mechanism, based on autocatalytic sets (ACSs), that is a
possible solution to this problem. We discuss a mathematical model describing
the population dynamics of molecules in a stylized but prebiotically plausible
chemistry. Large molecules can be produced in this chemistry by the coalescing
of smaller ones, with the smallest molecules, the `food set', being buffered.
Some of the reactions can be catalyzed by molecules within the chemistry with
varying catalytic strengths. Normally the concentrations of large molecules in
such a scenario are very small, diminishing exponentially with their size.
ACSs, if present in the catalytic network, can focus the resources of the
system into a sparse set of molecules. ACSs can produce a bistability in the
population dynamics and, in particular, steady states wherein the ACS molecules
dominate the population. However to reach these steady states from initial
conditions that contain only the food set typically requires very large
catalytic strengths, growing exponentially with the size of the catalyst
molecule. We present a solution to this problem by studying `nested ACSs', a
structure in which a small ACS is connected to a larger one and reinforces it.
We show that when the network contains a cascade of nested ACSs with the
catalytic strengths of molecules increasing gradually with their size (e.g., as
a power law), a sparse subset of molecules including some very large molecules
can come to dominate the system.Comment: 49 pages, 17 figures including supporting informatio
Menu labelling and food choice in obese adults: a feasibility study.
BACKGROUND: To date research examining the benefits of menu labelling in the UK is sparse. The aim of the present study was to examine the impact of menu labelling in a UK obese population. METHODS: Using a repeated measures design, 61 patients at a tier 3 weight management service completed four questionnaires to assess their food choice (control) and behaviour change when presented with 3 menu labelling formats (calorie content; nutrient content; and energy expenditure). RESULTS: All three forms of labelling increased participants weight control concerns compared to the control condition. There was a significant difference in content of food ordered in the three menu labelling formats compared to the control condition. The calorie condition had the largest percentage decrease in calories selected followed by energy expenditure and nutrient content. However, no difference was observed between the three conditions in the desire for menu labelling in restaurants to be introduced in the UK. CONCLUSIONS: The findings suggest that menu labelling should be enforced in the UK as it is both beneficial to promoting healthy eating and in demand. This study is the first to examine menu labelling in a UK obese population using energy expenditure equivalents to provide nutritional information
Activation of Akt by the Bacterial Inositol Phosphatase, SopB, is Wortmannin Insensitive
Salmonella enterica uses effector proteins translocated by a Type III Secretion System to invade epithelial cells. One of the invasion-associated effectors, SopB, is an inositol phosphatase that mediates sustained activation of the pro-survival kinase Akt in infected cells. Canonical activation of Akt involves membrane translocation and phosphorylation and is dependent on phosphatidyl inositide 3 kinase (PI3K). Here we have investigated these two distinct processes in Salmonella infected HeLa cells. Firstly, we found that SopB-dependent membrane translocation and phosphorylation of Akt are insensitive to the PI3K inhibitor wortmannin. Similarly, depletion of the PI3K regulatory subunits p85α and p85ß by RNAi had no inhibitory effect on SopB-dependent Akt phosphorylation. Nevertheless, SopB-dependent phosphorylation does depend on the Akt kinases, PDK1 and rictor-mTOR. Membrane translocation assays revealed a dependence on SopB for Akt recruitment to Salmonella ruffles and suggest that this is mediated by phosphoinositide (3,4) P2 rather than phosphoinositide (3,4,5) P3. Altogether these data demonstrate that Salmonella activates Akt via a wortmannin insensitive mechanism that is likely a class I PI3K-independent process that incorporates some essential elements of the canonical pathway
The Lid Domain of Caenorhabditis elegans Hsc70 Influences ATP Turnover, Cofactor Binding and Protein Folding Activity
Hsc70 is a conserved ATP-dependent molecular chaperone, which utilizes the energy of ATP hydrolysis to alter the folding state of its client proteins. In contrast to the Hsc70 systems of bacteria, yeast and humans, the Hsc70 system of C. elegans (CeHsc70) has not been studied to date
Meta-analysis of up to 622,409 individuals identifies 40 novel smoking behaviour associated genetic loci
Smoking is a major heritable and modifiable risk factor for many diseases, including cancer, common respiratory disorders and cardiovascular diseases. Fourteen genetic loci have previously been associated with smoking behaviour-related traits. We tested up to 235,116 single nucleotide variants (SNVs) on the exome-array for association with smoking initiation, cigarettes per day, pack-years, and smoking cessation in a fixed effects meta-analysis of up to 61 studies (up to 346,813 participants). In a subset of 112,811 participants, a further one million SNVs were also genotyped and tested for association with the four smoking behaviour traits. SNV-trait associations withP <5 x 10(-8)in either analysis were taken forward for replication in up to 275,596 independent participants from UK Biobank. Lastly, a meta-analysis of the discovery and replication studies was performed. Sixteen SNVs were associated with at least one of the smoking behaviour traits (P <5 x 10(-8)) in the discovery samples. Ten novel SNVs, including rs12616219 nearTMEM182, were followed-up and five of them (rs462779 inREV3L, rs12780116 inCNNM2, rs1190736 inGPR101, rs11539157 inPJA1, and rs12616219 nearTMEM182) replicated at a Bonferroni significance threshold (P <4.5 x 10(-3)) with consistent direction of effect. A further 35 SNVs were associated with smoking behaviour traits in the discovery plus replication meta-analysis (up to 622,409 participants) including a rare SNV, rs150493199, inCCDC141and two low-frequency SNVs inCEP350andHDGFRP2. Functional follow-up implied that decreased expression ofREV3Lmay lower the probability of smoking initiation. The novel loci will facilitate understanding the genetic aetiology of smoking behaviour and may lead to the identification of potential drug targets for smoking prevention and/or cessation.Peer reviewe
Association of genomic domains in BRCA1 and BRCA2 with prostate cancer risk and aggressiveness
Pathogenic sequence variants (PSV) in BRCA1 or BRCA2 (BRCA1/2) are associated with increased risk and severity of prostate cancer. Weevaluated whether PSVs inBRCA1/2 were associated with risk of overall prostate cancer or high grade (Gleason 8+) prostate cancer using an international sample of 65 BRCA1 and 171 BRCA2 male PSV carriers with prostate cancer, and 3,388 BRCA1 and 2,880 BRCA2 male PSV carriers without prostate cancer. PSVs in the 30 region of BRCA2 (c.7914+) were significantly associated with elevated risk of prostate cancer compared with reference bin c.1001c.7913 [HR = 1.78; 95% confidence interval (CI), 1.25-2.52; P = 0.001], as well as elevated risk of Gleason 8+ prostate cancer (HR = 3.11; 95% CI, 1.63-5.95; P = 0.001). c.756-c.1000 was also associated with elevated prostate cancer risk (HR = 2.83; 95% CI, 1.71-4.68; P = 0.00004) and elevated risk of Gleason 8+prostate cancer (HR = 4.95; 95% CI, 2.12-11.54; P = 0.0002). No genotype-phenotype associations were detected for PSVs in BRCA1. These results demonstrate that specific BRCA2 PSVs may be associated with elevated risk of developing aggressive prostate cancer. Significance: Aggressive prostate cancer risk in BRCA2 mutation carriers may vary according to the specific BRCA2 mutation inherited by the at-risk individual.Peer reviewe
Evidence of causal effect of major depression on alcohol dependence: findings from the psychiatric genomics consortium
BACKGROUND
Despite established clinical associations among major depression (MD), alcohol dependence (AD), and alcohol consumption (AC), the nature of the causal relationship between them is not completely understood. We leveraged genome-wide data from the Psychiatric Genomics Consortium (PGC) and UK Biobank to test for the presence of shared genetic mechanisms and causal relationships among MD, AD, and AC.
METHODS
Linkage disequilibrium score regression and Mendelian randomization (MR) were performed using genome-wide data from the PGC (MD: 135 458 cases and 344 901 controls; AD: 10 206 cases and 28 480 controls) and UK Biobank (AC-frequency: 438 308 individuals; AC-quantity: 307 098 individuals).
RESULTS
Positive genetic correlation was observed between MD and AD (rgMD−AD = + 0.47, P = 6.6 × 10−10). AC-quantity showed positive genetic correlation with both AD (rgAD−AC quantity = + 0.75, P = 1.8 × 10−14) and MD (rgMD−AC quantity = + 0.14, P = 2.9 × 10−7), while there was negative correlation of AC-frequency with MD (rgMD−AC frequency = −0.17, P = 1.5 × 10−10) and a non-significant result with AD. MR analyses confirmed the presence of pleiotropy among these four traits. However, the MD-AD results reflect a mediated-pleiotropy mechanism (i.e. causal relationship) with an effect of MD on AD (beta = 0.28, P = 1.29 × 10−6). There was no evidence for reverse causation.
CONCLUSION
This study supports a causal role for genetic liability of MD on AD based on genetic datasets including thousands of individuals. Understanding mechanisms underlying MD-AD comorbidity addresses important public health concerns and has the potential to facilitate prevention and intervention efforts
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