Association of common polymorphisms in GLUT9 gene with gout but not with coronary artery disease in a large case-control study

Background

Serum uric acid (UA) levels have recently been shown to be genetically influenced by common polymorphisms in the GLUT9 gene in two genome-wide association analyses of Italian and British populations. Elevated serum UA levels are often found in conjunction with the metabolic syndrome. Hyperuricemia is the major risk factor for gout and has been associated with increased cardiovascular morbidity and mortality. The aim of the present study was to further elucidate the association of polymorphisms in GLUT9 with gout and coronary artery disease (CAD) or myocardial infarction (MI). To test our hypotheses, we performed two large case-control association analyses of individuals from the German MI Family Study.

Methods and Findings

First, 665 patients with gout and 665 healthy controls, which were carefully matched for age and gender, were genotyped for four single nucleotide polymorphisms (SNPs) within or near the GLUT9 gene. All four SNPs demonstrated highly significant association with gout. SNP rs6855911, located within intron 7 of GLUT9, showed the strongest signal with a protective effect of the minor allele with an allelic odds ratio of 0.62 (95% confidence interval 0.52–0.75; p  =  3.2*10⁻⁷). Importantly, this finding was not influenced by adjustment for components of the metabolic syndrome or intake of diuretics. Secondly, 1,473 cases with severe CAD or MI and 1,241 healthy controls were tested for the same four GLUT9 SNPs. The analyses revealed, however, no significant association with CAD or with MI. Additional screening of genome-wide association data sets showed no signal for CAD or MI within the GLUT9 gene region.

Conclusion

Thus, our results provide compelling evidence that common genetic variations within the GLUT9 gene strongly influence the risk for gout but are unlikely to have a major effect on CAD or MI in a German population.     

Repeated neonatal separation stress alters the composition of neurochemically characterized interneuron subpopulations in the rodent dentate gyrus and basolateral amygdala

Emotional experience during early life has been shown to interfere with the development of excitatory synaptic networks in the prefrontal cortex, hippocampus, and the amygdala of rodents and primates. The aim of the present study was to investigate a developmental "homoeostatic synaptic plasticity" hypothesis and to test whether stress-induced changes of excitatory synaptic composition are counterbalanced by parallel changes of inhibitory synaptic networks. The impact of repeated early separation stress on the development of two GABAergic neuronal subpopulations was quantitatively analyzed in the brain of the semiprecocial rodent Octodon degus. Assuming that PARV- and CaBP-D28k-expression are negatively correlated to the level of inhibitory activity, the previously described reduced density of excitatory spine synapses in the dentate gyrus of stressed animals appears to be "amplified" by elevated GABAergic inhibition, reflected by reduced PARV- (down to 85%) and CaBP-D28k-immunoreactivity (down to 74%). In opposite direction, the previously observed elevated excitatory spine density in the CA1 region of stressed animals appears to be amplified by reduced inhibition, reflected by elevated CaPB-D28k-immunoreactivity (up to 149%). In the (baso)lateral amygdala, the previously described reduction of excitatory spine synapses appears to be "compensated" by reduced inhibitory activity, reflected by dramatically elevated PARV- (up to 395%) and CaPB-D28k-immunoreactivity (up to 327%). No significant differences were found in the central nucleus of the amygdala, the piriform, and somatosensory cortices and in the hypothalamic paraventricular nucleus. Thus during stress-evoked neuronal and synaptic reorganization, a homeostatic balance between excitation and inhibition is not maintained in all regions of the juvenile brain.     

Polyvinylamine‐coated polyester fibers as a carrier matrix for the immobilization of peroxidases

Biocatalytic transformations that employ immobilized enzymes become increasingly important for industrial applications. Synthetic or natural textile fiber materials such as polyester, polyamide or viscose are support materials that are comparatively inexpensive. Contrary to traditional support materials, their flexibility enables their use in reactors of any geometry and a fast and residue‐free removal from batch reactors. In this study a permanently immobilized peroxidase (Baylase®) has been investigated on polyester felt as a solid support as a new heterogeneous catalyst system. The polyester felt was functionalized by coating with polyvinylamine and subsequent activation with glutaraldehyde as a crosslinking agent. The enzyme load on the textile surface, the activity of the immobilized protein after repeated use as well as the storage stability was evaluated. Scanning electron micrographs and UV Vis spectroscopy made it possible to verify the enzyme immobilization on the textile surface. Furthermore, the load of immobilized peroxidase was determined by ICP OE spectrometry to be 9–12 mg per gram of textile. The activity of immobilized Baylase® remained high over 35 reaction cycles and a storage period of 8 weeks.     

Fitness change in relation to mutation number in spontaneous mutation accumulation lines of Chlamydomonas reinhardtii

Although all genetic variation ultimately stems from mutations, their properties are difficult to study directly. Here, we used multiple mutation accumulation (MA) lines derived from five genetic backgrounds of the green algae Chlamydomonas reinhardtii that have been previously subjected to whole genome sequencing to investigate the relationship between the number of spontaneous mutations and change in fitness from a nonevolved ancestor. MA lines were on average less fit than their ancestors and we detected a significantly negative correlation between the change in fitness and the total number of accumulated mutations in the genome. Likewise, the number of mutations located within coding regions significantly and negatively impacted MA line fitness. We used the fitness data to parameterize a maximum likelihood model to estimate discrete categories of mutational effects, and found that models containing one to two mutational effect categories (one neutral and one deleterious category) fitted the data best. However, the best‐fitting mutational effects models were highly dependent on the genetic background of the ancestral strain.     

Incus facet morphology in carnivorous mammals from different ecosystems: Taxonomy vs. habitat

This study is prompted by the discovery of an incus of Hyaenodon, the first known auditory ossicle of this genus and thus of any hyaenodont mammal so far. A large set of incudes of recent Carnivora, including felids, hyaenids, viverrids, herpestids, nandiniid and canids of different ecosystems, was set up for morphological comparison. This study examines especially the incudo-mallear facet. Typically, the incudo-mallear facet is composed of: (1) three articular surfaces in felids, (2) a U-shaped surface in hyaenids and (3) four surfaces in canids. Both taxonomy (on family level) and habitat (open, closed or mixed habitat preference) might have an impact on the morphology of the incus facets, the former having a major impact in our sample. The Hyaenodon incus is small, delicate and possesses an incudo-mallear facet of a general saddle-shape with two articulation facets, a large superior articulation area and a circular, inferior articulation area. Herein, its general morphology and facet shape is most similar to the felid incus morphology.     

Enrichment of anaerobic nitrate-dependent methanotrophic ‘ Candidatus Methanoperedens nitroreducens’ archaea from an Italian paddy field soil

Paddy fields are a significant source of methane and contribute up to 20% of total methane emissions from wetland ecosystems. These inundated, anoxic soils featuring abundant nitrogen compounds and methane are an ideal niche for nitrate-dependent anaerobic methanotrophs. After 2 years of enrichment with a continuous supply of methane and nitrate as the sole electron donor and acceptor, a stable enrichment dominated by ‘Candidatus Methanoperedens nitroreducens’ archaea and ‘Candidatus Methylomirabilis oxyfera’ NC10 phylum bacteria was achieved. In this community, the methanotrophic archaea supplied the NC10 phylum bacteria with the necessary nitrite through nitrate reduction coupled to methane oxidation. The results of qPCR quantification of 16S ribosomal RNA (rRNA) gene copies, analysis of metagenomic 16S rRNA reads, and fluorescence in situ hybridization (FISH) correlated well and showed that after 2 years, ‘Candidatus Methanoperedens nitroreducens’ had the highest abundance of (2.2 ± 0.4 × 108) 16S rRNA copies per milliliter and constituted approximately 22% of the total microbial community. Phylogenetic analysis showed that the 16S rRNA genes of the dominant microorganisms clustered with previously described ‘Candidatus Methanoperedens nitroreducens ANME2D’ (96% identity) and ‘Candidatus Methylomirabilis oxyfera’ (99% identity) strains. The pooled metagenomic sequences resulted in a high-quality draft genome assembly of ‘Candidatus Methanoperedens nitroreducens Vercelli’ that contained all key functional genes for the reverse methanogenesis pathway and nitrate reduction. The diagnostic mcrA gene was 96% similar to ‘Candidatus Methanoperedens nitroreducens ANME2D’ (WP_048089615.1) at the protein level. The ‘Candidatus Methylomirabilis oxyfera’ draft genome contained the marker genes pmoCAB, mdh, and nirS and putative NO dismutase genes. Whole-reactor anaerobic activity measurements with methane and nitrate revealed an average methane oxidation rate of 0.012 mmol/h/L, with cell-specific methane oxidation rates up to 0.57 fmol/cell/day for ‘Candidatus Methanoperedens nitroreducens’. In summary, this study describes the first enrichment and draft genome of methanotrophic archaea from paddy field soil, where these organisms can contribute significantly to the mitigation of methane emissions.     

Bioinformatic analysis of fold-type III PLP-dependent enzymes discovers multimeric racemases

Pyridoxal-5′-phosphate (PLP)-dependent enzymes are ubiquitous in nature and catalyze a variety of important metabolic reactions. The fold-type III PLP-dependent enzyme family is primarily comprised of decarboxylases and alanine racemases. In the development of a multiple structural alignment database (3DM) for the enzyme family, a large subset of 5666 uncharacterized proteins with high structural, but low sequence similarity to alanine racemase and decarboxylases was found. Compared to these two classes of enzymes, the protein sequences being the object of this study completely lack the C-terminal domain, which has been reported important for the formation of the dimer interface in other fold-type III enzymes. The 5666 sequences cluster around four protein templates, which also share little sequence identity to each other. In this work, these four template proteins were solubly expressed in Escherichia coli, purified, and their substrate profiles were evaluated by HPLC analysis for racemase activity using a broader range of amino acids. They were found active only against alanine or serine, where they exhibited Michaelis constants within the range of typical bacterial alanine racemases, but with significantly lower turnover numbers. As the already described racemases were proposed to be active and appeared to be monomers as judged from their crystal structures, we also investigated this aspect for the four new enzymes. Here, size exclusion chromatography indicated the presence of oligomeric states of the enzymes and a native-PAGE in-gel assay showed that the racemase activity was present only in an oligomeric state but not as monomer. This suggests the likelihood of a different behavior of these enzymes in solution compared to the one observed in crystalline form.

     

Hsp90 inhibitors radicicol and geldanamycin have opposing effects on <Emphasis Type="Italic">Leishmania</Emphasis> Aha1-dependent proliferation

Hsp90 and its co-chaperones are essential for the medically important parasite Leishmania donovani, facilitating life cycle control and intracellular survival. Activity of Hsp90 is regulated by co-chaperones of the Aha1 and P23 families. In this paper, we studied the expression of L. donovani Aha1 in two life cycle stages, its interaction with Hsp90 and the phenotype of Aha1 null mutants during the insect stage and inside infected macrophages. This study provides a detailed in vitro analysis of the function of Aha1 in Leishmania parasites and the first instance of a reverse genetic analysis of Aha1 in a protozoan parasite. While Aha1 is non-essential under standard growth conditions and at elevated temperature, Aha1 protects against ethanol stress. However, both overexpression and lack of Aha1 affected parasite growth in the presence of the Hsp90 inhibitors radicicol (RAD) and geldanamycin (GA). Under RAD pressure, P23 and Aha1 act in an antagonistic way. By contrast, expression levels of both co-chaperones have similar effects under GA treatment, indicating different inhibition mechanisms by the two compounds. Aha1 is also secreted in virulence-enhancing exosomes. This may explain why the loss of Aha1 reduces the infectivity of L. donovani in ex vivo mouse macrophages, indicating a role during the intracellular mammalian stage.     

No obvious genetic erosion,but evident relict status at the westernmost range edge of the Pontic‐Pannonian steppe plant Linum flavum L. (Linaceae) in Central Europe

We investigate patterns of genetic variation along an east–west transect of Central European populations of Linum flavum and interpret the Quaternary history of its peripheral populations, especially those at the westernmost isolated range edge, discussing their migrations and possible relict status. We defined our peripheral transect across three study regions from Central Hungary, eastern Austria to southwestern Germany. Using AFLP fingerprinting and cpDNA sequence variation (rpL16 intron, atpI‐H), we analyzed 267 and 95 individuals, respectively, representing each study region by four populations. Hierarchical AMOVA (AFLPs) indicated significant variation among study regions (12% of total variance) and moderate differentiation between populations (10%). Population differentiation was high at the westernmost range edge (11.5%, Germany), but also in the east (13.4%, Hungary), compared to the Austrian study region (8.6%). Correspondingly, AFLP diversity was highest in the center of the study transect in eastern Austria. CpDNA haplotypes support a pattern of regional structuring with the strongest separation of the westernmost range edge, and some haplotype sharing among Austrian and Hungarian individuals. Equilibrating nucleotide versus haplotype diversity patterns, the highly diverse populations at the Pannonian range edge (Austria) indicate long‐term persistence, while Central Pannonian populations are obviously effected by recent bottlenecks. Intermediate nucleotide, but high haplotype diversity within the westernmost exclave (Swabian Alb), is indicative of a founder bottleneck during its pre‐LGM or early postglacial migration history, followed by sufficient time to accumulate cpDNA variation. The not obviously reduced genetic diversity and distinctiveness of L. flavum at the westernmost range edge suggest a long‐term persistence (relict status) of populations in this region, where the species has survived probably even the Würm glaciation in extra‐Mediterranean refugia. This genetic relict variation represents an important part of the overall genetic diversity found in the western periphery of this steppe plant and highlights the high conservation priority of respective gene pools.     

Children Love Their Pets: Do Relationships between Children and Pets Co-vary with Taxonomic Order,Gender, and Age?

Generally, children love their pets. However, a deeper insight into the beneficial effects of pets on the physical, psychological, and social wellbeing and development of children is needed. This study investigated whether children have more intense relationships with animals which are behaviorally similar to humans (according to the scala naturae), and whether the relationship patterns between 11- to 14-year-old children (n = 72) and their pets differ from those in prepubescent children, between 6 and 10 years of age (n = 84). We also investigated whether pet-relationship quality is associated with children’s age, gender, and number of siblings. Data about individual bonding type and attachment quality between the children and their pet were collected using a questionnaire. The results indicate that the younger children’s relationships clearly co-varied with taxonomic order of the pet. In contrast, 11- to 14-year-old children reported similarly high scores of attachment with their mouse or iguana as with their dog or cat, and the relationship patterns did not co-vary with taxonomic order. Gender effects on relationship quality were found in both age groups; especially girls reported intense relationships with their pets. In addition to gender, children without siblings had stronger attachment to their pet than children who had siblings. Our data suggest that young children develop high-quality relationships with pets, particularly those which are taxonomically closely related, such as dogs and cats, and less so with other pet species, such as birds or fish. Older children were also able to strongly attach to other pet species. We argue that mental relationship representations change during puberty and that older (11- to 14-year-old) children may no longer make attachments to pets based on them being behaviorally similar to people.