Rapid one-step biotinylation of biological and non-biological surfaces

We describe a rapid one-step method to biotinylate virtually any biological or non-biological surface. Contacting a solution of biotin-spacer-lipid constructs with a surface will form a coating within seconds on non-biological surfaces or within minutes on most biological membranes including membrane viruses. The resultant biotinylated surface can then be used to interact with avidinylated conjugates, beads, vesicles, surfaces or cells

A synthetic biology approach to probing nucleosome symmetry

The repeating subunit of chromatin, the nucleosome, includes two copies of each of the four core histones, and several recent studies have reported that asymmetrically-modified nucleosomes occur at regulatory elements in vivo. To probe the mechanisms by which histone modifications are read out, we designed an obligate pair of H3 heterodimers, termed H3X and H3Y, which we extensively validated genetically and biochemically. Comparing the effects of asymmetric histone tail point mutants with those of symmetric double mutants revealed that a single methylated H3K36 per nucleosome was sufficient to silence cryptic transcription in vivo. We also demonstrate the utility of this system for analysis of histone modification crosstalk, using mass spectrometry to separately identify modifications on each H3 molecule within asymmetric nucleosomes. The ability to generate asymmetric nucleosomes in vivo and in vitro provides a powerful and generalizable tool to probe the mechanisms by which H3 tails are read out by effector proteins in the cell

Late Ordovician beachrock as a far-field indicator for glacial meltwater pulse

Understanding ancient climate changes is hampered by the inability to disentangle trends in continental ice volume from records of relative sea-level change. As a unique coastal deposit in tropical and subtropical regions, beachrock has been proved to be reliable for constraining the glacial meltwater signal and thus the total volume of land-based ice in Quaternary. However, beachrock is rarely recognized in the fossil record due to (a) the two-dimensional distribution of beach deposits, as opposed, for example, to extended platform sediments, and (b) the fact that specific environmental conditions are required in order to lithify sediments directly on the beach. By combining the stratigraphic architecture with petrography of characteristic carbonate cements, we demonstrate the first known occurrence of Ordovician beachrock in the Tarim Block, northwestern China. According to biostratigraphic data, a middle Katian (Upper Ordovician) palaeokarst surface is capped by carbonate conglomerate beachrock and this is suggesting a significant relative sea-level rise in late Katian. The beachrock can be correlated with widespread subaerial exposure surfaces and a pronounced stratigraphic gap within the Katian in northwestern Tarim. We suggest that the beachrock âfingerprintedâ a strong melt-water pulse in high latitudes after a short-lived Katian glaciation, which has not received much attention in scientific papers so far

Changes in serum biomarker profiles after percutaneous mitral valve repair with the MitraClip system

Background: Mitral regurgitation (MR) is one of the most common valvular diseases. Percu­taneous mitral valve repair with the MitraClipTM system is a novel percutaneous mitral valve repair (PMVR) technique for high-surgical-risk patients. However, the effect of PMVR on cir­culating cardiac or inflammatory biomarkers and their association with individual functional, echocardiographic and clinical outcomes is poorly investigated. Methods: A group of 144 patients with functional or degenerative MR (age, 75 ± 11 years; 41% females) underwent PMVR with the MitraClip system at the University Heart Center Zu­rich. Serum biomarkers as N-terminal pro-B-type natriuretic peptide (NT-proBNP), C-reactive protein (CRP) and creatinine were obtained from venous sampling at baseline and follow-up of 3–6 months. Results: Median NT-proBNP decreased insignificantly from 2,942 (IQR 1,596–5,722) to 2,739 (IQR 1,440–4,296) ng/L, p = 0.21. NT-proBNP changes did not correlate with baseline left ventricular (LV) ejection fraction or LV dimensions, with New York Heart Association class on follow-up, or with clinical events on follow-up. CRP levels reached a peak on the third postoperative day at 34.0 mg/L with a subsequent slow decrease over the ensuing days. Conclusions: Despite successful PMVR, NT-proBNP remain fairly unchanged on follow-up and changes in NT-proBNP levels are poor predictors of functional improvement or clinical outcome after MitraClip treatment

Changes in serum biomarker profiles after percutaneous mitral valve repair with the MitraClip system

BACKGROUND Mitral regurgitation (MR) is one of the most common valvular diseases. Percu-taneous mitral valve repair with the MitraClipTM system is a novel percutaneous mitral valve repair (PMVR) technique for high-surgical-risk patients. However, the effect of PMVR on cir-culating cardiac or inflammatory biomarkers and their association with individual functional, echocardiographic and clinical outcomes is poorly investigated. METHODS A group of 144 patients with functional or degenerative MR (age, 75 ± 11 years; 41% females) underwent PMVR with the MitraClip system at the University Heart Center Zu-rich. Serum biomarkers as N-terminal pro-B-type natriuretic peptide (NT-proBNP), C-reactive protein (CRP) and creatinine were obtained from venous sampling at baseline and follow-up of 3-6 months. RESULTS Median NT-proBNP decreased insignificantly from 2,942 (IQR 1,596-5,722) to 2,739 (IQR 1,440-4,296) ng/L, p = 0.21. NT-proBNP changes did not correlate with baseline left ventricular (LV) ejection fraction or LV dimensions, with New York Heart Association class on follow-up, or with clinical events on follow-up. CRP levels reached a peak on the third postoperative day at 34.0 mg/L with a subsequent slow decrease over the ensuing days. CONCLUSIONS Despite successful PMVR, NT-proBNP remain fairly unchanged on follow-up and changes in NT-proBNP levels are poor predictors of functional improvement or clinical outcome after MitraClip treatment

The correlation between reading and mathematics ability at age twelve has a substantial genetic component

Dissecting how genetic and environmental influences impact on learning is helpful for maximizing numeracy and literacy. Here we show, using twin and genome-wide analysis, that there is a substantial genetic component to children’s ability in reading and mathematics, and estimate that around one half of the observed correlation in these traits is due to shared genetic effects (so-called Generalist Genes). Thus, our results highlight the potential role of the learning environment in contributing to differences in a child’s cognitive abilities at age twelve

Facultative Symbiont Infections Affect Aphid Reproduction

Some bacterial symbionts alter their hosts reproduction through various mechanisms that enhance their transmission in the host population. In addition to its obligatory symbiont Buchnera aphidicola, the pea aphid Acyrthosiphon pisum harbors several facultative symbionts influencing several aspects of host ecology. Aphids reproduce by cyclical parthenogenesis whereby clonal and sexual reproduction alternate within the annual life cycle. Many species, including the pea aphid, also show variation in their reproductive mode at the population level, with some lineages reproducing by cyclical parthenogenesis and others by permanent parthenogenesis. While the role of facultative symbionts has been well studied during the parthenogenetic phase of their aphid hosts, very little is known on their possible influence during the sexual phase. Here we investigated whether facultative symbionts modulate the capacity to produce sexual forms in various genetic backgrounds of the pea aphid with controlled symbiont composition and also in different aphid genotypes from natural populations with previously characterized infection status and reproductive mode. We found that most facultative symbionts exhibited detrimental effects on their hosts fitness under sex-inducing conditions in comparison with the reference lines. We also showed that the loss of sexual phase in permanently parthenogenetic lineages of A. pisum was not explained by facultative symbionts. Finally, we demonstrated that Spiroplasma infection annihilated the production of males in the host progeny by inducing a male-killing phenotype, an unexpected result for organisms such as aphids that reproduce primarily through clonal reproduction