In many marine fish species, genetic population structure is typically weak because populations are large, evolutionarily young and have a high potential for gene flow. We tested whether genetic ...markers influenced by natural selection are more efficient than the presumed neutral genetic markers to detect population structure in Atlantic herring (Clupea harengus), a migratory pelagic species with large effective population sizes. We compared the spatial and temporal patterns of divergence and statistical power of three traditional genetic marker types, microsatellites, allozymes and mitochondrial DNA, with one microsatellite locus, Cpa112, previously shown to be influenced by divergent selection associated with salinity, and one locus located in the major histocompatibility complex class IIA (MHC-IIA) gene, using the same individuals across analyses. Samples were collected in 2002 and 2003 at two locations in the North Sea, one location in the Skagerrak and one location in the low-saline Baltic Sea. Levels of divergence for putatively neutral markers were generally low, with the exception of single outlier locus/sample combinations; microsatellites were the most statistically powerful markers under neutral expectations. We found no evidence of selection acting on the MHC locus. Cpa112, however, was highly divergent in the Baltic samples. Simulations addressing the statistical power for detecting population divergence showed that when using Cpa112 alone, compared with using eight presumed neutral microsatellite loci, sample sizes could be reduced by up to a tenth while still retaining high statistical power. Our results show that the loci influenced by selection can serve as powerful markers for detecting population structure in high gene-flow marine fish species.
Angiopoietin-like protein 4 (Angptl4) is a circulating inhibitor of plasma triglyceride clearance via inhibition of lipoprotein lipase. The aim of the present study was to examine the regulation of ...Angptl4 by glucocorticoids and insulin in vivo in humans, since these factors regulate Angptl4 expression in vitro.
In a randomized, placebo-controlled, double-blind, dose-response intervention study, 32 healthy males (age: 22 ± 3 years; BMI 22.4 ± 1.7 kg m⁻²) were allocated to prednisolone 30 mg once daily (n = 12), prednisolone 7.5 mg once daily (n = 12), or placebo (n = 8) for 2 weeks. Angptl4 levels and lipid metabolism were measured before and at 2 weeks of treatment, in the fasted state and during a 2-step hyperinsulinemic clamp. Additionally, human hepatoma cells were treated with dexamethasone and/or insulin.
Compared to placebo, prednisolone treatment tended to lower fasting Angptl4 levels (P = 0.073), raised fasting insulin levels (P = 0.0004) and decreased fasting nonesterified fatty acid concentrations (NEFA) (P = 0.017). Insulin infusion reduced Angptl4 levels by 6 % (plasma insulin ~200 pmol/l, P = 0.006) and 22 % (plasma insulin ~600 pmol/l, P < 0.0001), which was attenuated by prednisolone treatment (P = 0.03). Prednisolone 7.5 mg and 30 mg dose-dependently decreased insulin-mediated suppression of lipolysis (by 11 ± 5 % and 34 ± 6 % respectively). Prednisolone 30 mg enhanced fasting triglyceride levels ( P = 0.028). Plasma Angptl4 was not related to prednisolone-induced changes in lipid metabolism. In human hepatoma cells, dexamethasone increased Angptl4 mRNA expression and protein secretion, whereas insulin had the opposite effect.
Insulin lowers plasma Angptl4 levels in humans by lowering NEFA and by inhibiting Angptl4 expression and release. Glucocorticoids counteract insulin-mediated suppression of Angptl4.
An Atlantic herring major histocompatibility class II A (Clha‐DAA) cDNA sequence has been characterized and was shown to encode a leader peptide, alpha‐1 domain, alpha‐2 domain, connecting peptide, ...transmembrane and cytoplasmic region. The Clha‐DAA protein sequence has all the characteristics of a teleost class II A protein with conserved cysteines in both the alpha‐1 and the alpha‐2 domains and two potential N‐linked glycosylation sites. Exon 2 sequences encoding the polymorphic alpha‐1 domain from different individuals were analysed and revealed the presence of at least two loci. The Clha‐DAA gene consists of four exons and three short introns. Four unique intron 3 sequences from multiple individuals were obtained and were shown to contain a (TG)n microsatellite sequence. Primers were optimized such that only a single microsatellite locus designated Clha‐DAA‐INTR3 was amplified. Four herring populations from the North Sea and the Baltic Sea were genotyped for Clha‐DAA‐INTR3. In total, 16 Clha‐DAA‐INTR3 alleles were detected; the distribution of the alleles showed no deviation from Hardy–Weinberg expectation. Levels of genetic differentiation among samples were of similar magnitude as have been reported earlier for neutral microsatellite loci between northern North Sea and Baltic Sea herring populations.
Sequence-based typing of a breeding population (G1) consisting of 84 Atlantic salmon individuals revealed the presence of 7 Sasa-DAA and 7 Sasa-DAB expressed alleles. Subsequent typing of 1,182 ...individuals belonging to 33 families showed that Sasa-DAA and Sasa-DAB segregate as haplotypes. In total seven unique haplotypes were established, with frequencies in the population studied ranging from 0.01 to 0.49. Each haplotype is characterized by a unique minisatellite marker size embedded in the 3' untranslated region of the Sasa-DAA gene. These data corroborate the fact that Atlantic salmon express a single class II locus, consisting of tightly linked class II A and class B genes. The seven haplotypes give rise to 15 genotypes with frequencies varying between 0.01 and 0.23; 21 class II homozygous individuals were present in the G1 population. We also studied the frequency distribution in another breeding population (G4, n=374) using the minisatellite marker. Only one new marker size was present, suggesting the presence of one new class II haplotype. The marker frequency distribution in the G4 population differed markedly from the G1 population. The genomic organizations of two Sasa-DAA and Sasa-DAB alleles were determined, and supported the notion that these alleles belong to the same locus. In contrast to other studies of salmonid class II sequences, phylogenetic analyses of brown trout and Atlantic class II A and class II B sequences provided support for trans-species polymorphism.
Plasma lipoprotein levels are determined by the balance between lipoprotein production and clearance. Recently, angiopoietin-like protein 4 (ANGPTL4) was uncovered as a novel endocrine factor that ...potently raises plasma triglyceride levels by inhibiting triglyceride clearance. However, very little is known about ANGPTL4 in human. Here we set out to identify physiological determinants of plasma ANGPTL4 levels in humans, focusing on the effect of energy restriction and plasma FFAs.
We developed an ELISA for quantitative measurement of ANGPTL4 in human plasma. Using this assay we found major variations in baseline plasma ANGPTL4 levels between individuals. Within an individual, plasma ANGPTL4 levels remain stable throughout the day but increase significantly in response to long-term fasting, chronic caloric restriction, and endurance exercise. Intralipid injection as well as treatment with a beta-adrenergic agonist, both of which lead to elevated plasma FFA levels, increased plasma ANGPTL4 levels compared to control treatment. Fatty acids markedly induced ANGPTL4 gene expression in rat hepatoma FAO cells, human primary myocytes, and mouse intestinal MSIE cells.
In conclusion, our results show that plasma ANGPTL4 levels are increased by fasting, caloric restriction, and exercise, which is likely mediated by elevated plasma FFAs.
Yeast surface display libraries of human IgG1 Fc regions were prepared in which loop sequences at the C-terminal tip of the CH3 domain were randomized. A high percentage of these library members ...bound to soluble CD64 and Protein A indicating that the randomization step did not grossly interfere with the overall structure of the displayed Fc. Sorting these libraries by FACS for binders against HER2/neu yielded antigen-specific Fc binders (Fcab; Fc antigen binding) of which one was affinity matured, resulting in Fcab clone H10-03-6 which showed >10-fold improvement in antigen-binding activity versus the parental clone. Pre-equilibrium surface plasmon resonance experiments revealed a KD value of 69 nM. H10-03-6 did not react with other members of the HER family and specifically interacted with HER2-positive but not with HER2-negative cells. Importantly, Fcab H10-03-6 elicited potent antibody-dependent cellular cytotoxicity in vitro. Finally, the in vivo half-life in mice was similar to wild-type Fc indicating that the amino acid changes in the CH3 domain did not affect the pharmacokinetic behavior of the recombinant Fc. Our data demonstrate that the Fcab scaffold combines all features of normal antibodies in a small 50 kD homodimeric protein: antigen binding, effector functions and long half-life in vivo.
Uniform Flow in Bubble Columns Mudde, R. F; Harteveld, W. K; van den Akker, H. E. A
Industrial & engineering chemistry research,
01/2009, Letnik:
48, Številka:
1
Journal Article
Recenzirano
Uniform bubbly flow in a 15 cm bubble column is investigated. We use a special needle sparger consisting of 559 separate needles, uniformly distributed over the bottom. With this sparger, we can ...ensure that all bubbles generated are of the same size and that the bubble injection is very uniform over the entire bottom of the column. Detailed experiments are reported, using optical glass fibers to measure the local gas fraction and bubble size and velocity and using laser Doppler anemometry to measure the liquid axial velocity field. We find that the homogeneous flow regime extends up to a gas fraction of 55% well beyond the predictions of theory. The superficial gas velocity at which the homogeneous regime looses its stability depends on the water quality: fresh water looses its stability much earlier than old water. However, the gas fraction as a function of the superficial gas velocity is in the homogeneous regime independent of the water quality. The overall gas fraction can be described by a Richardson and Zaki type of relation or by the proposal by Garnier et al. We have indications that, at the point of instability, the bubble size has increased to a critical value at which the lift force reverses sign. This causes the radial gas fraction to change from flat with a small wall peaking to core peaking provoking the instability as suggested by Lucas et al. Chem. Eng. Technol. 2005, 60, 3609 . Alternatively, at higher gas fractions, the swarm gets denser and the bubble wakes get suppressed. According to Fox and co-workers Chem. Eng. Sci. 2007, 62, 3159 , this causes the flow to lose its stability.
CAN OUTSIDERS HELP? Jenne, Erin K; Mudde, Cas
Journal of democracy,
07/2012, Letnik:
23, Številka:
3
Journal Article
Recenzirano
Yet a number of factors hamstring outsiders' ability to persuade Fidesz to reverse its illiberal policies. Because Fidesz came to power through free and fair elections and Orbán is not a radical ...right-wing ideologue like the late Jörg Haider in Austria, the EU has had difficulty framing a valid legal argument against the Fidesz leadership. Orbán has consistently claimed democratic legitimacy, while noting the lack of democratic accountability in the EU and IMF.\n Thus foreign support for the opposition would risk discrediting the movement altogether. ...even if the opposition succeeded in taking back the government in the next elections, Fidesz has achieved a grip over the country's public institutions so tight that it will likely require more than a mere change in political leadership to unclench it.
This paper discusses the role of the gas injection pattern on the large scale structures in a homogeneous pseudo-2D bubble column operated at relatively high gas hold-ups up to 8%. Seven cases with ...different inlet configuration have been studied experimentally by Harteveld et al. Each of these cases has been simulated using a (parallel) Euler–Lagrange model developed by Darmana et al. The presence of coherent structures for both uniform and non-uniform gas injection is studied. Furthermore, the influence of the gas injection pattern on the dynamics is investigated, while the statistical (average and fluctuating) quantities are compared with the PIV/PTV and LDA measurement data of Harteveld et al. The results show that the model resembles the observed experimental flow structures to a large extent.
PDF
