High-throughput glycopeptide profiling of prostate-specific antigen from seminal plasma by MALDI-MS

An altered total seminal plasma glycosylation has been associated with male infertility, and the highly abundant seminal plasma glycoprotein prostate-specific antigen (PSA) plays an important role in fertilization. However, the exact role of PSA glycosylation in male fertility is not clear. To understand the involvement of PSA glycosylation in the fertilization process, analytical methods are required to study the glycosylation of PSA from seminal plasma with a high glycoform resolution and in a protein-specific manner. In this study, we developed a novel, high-throughput PSA glycopeptide workflow, based on matrix-assisted laser desorption/ionization-mass spectrometry, allowing the discrimination of sialic acid linkage isomers via the derivatization of glycopeptides. The method was successfully applied on a cohort consisting of seminal plasma from infertile and fertile men (N = 102). Forty-four glycopeptides were quantified in all samples, showing mainly complex-type glycans with high levels of fucosylation and sialylation. In addition, N,N-diacetyllactosamine (LacdiNAc) motives were found as well as hybrid-type and high mannose-type structures. Our method showed a high intra- and interday repeatability and revealed no difference in PSA glycosylation between fertile and infertile men. Next to seminal plasma, the method is also expected to be of use for studying PSA glycopeptides derived from other biofluids and/or in other disease contexts.Proteomic

Multiple Neural Oscillators and Muscle Feedback Are Required for the Intestinal Fed State Motor Program

After a meal, the gastrointestinal tract exhibits a set of behaviours known as the fed state. A major feature of the fed state is a little understood motor pattern known as segmentation, which is essential for digestion and nutrient absorption. Segmentation manifests as rhythmic local constrictions that do not propagate along the intestine. In guinea-pig jejunum in vitro segmentation constrictions occur in short bursts together with other motor patterns in episodes of activity lasting 40–60 s and separated by quiescent episodes lasting 40–200 s. This activity is induced by luminal nutrients and abolished by blocking activity in the enteric nervous system (ENS). We investigated the enteric circuits that regulate segmentation focusing on a central feature of the ENS: a recurrent excitatory network of intrinsic sensory neurons (ISNs) which are characterized by prolonged after-hyperpolarizing potentials (AHPs) following their action potentials. We first examined the effects of depressing AHPs with blockers of the underlying channels (TRAM-34 and clotrimazole) on motor patterns induced in guinea-pig jejunum, in vitro, by luminal decanoic acid. Contractile episode durations increased markedly, but the frequency and number of constrictions within segmenting bursts and quiescent period durations were unaffected. We used these observations to develop a computational model of activity in ISNs, excitatory and inhibitory motor neurons and the muscle. The model predicted that: i) feedback to ISNs from contractions in the circular muscle is required to produce alternating activity and quiescence with the right durations; ii) transmission from ISNs to excitatory motor neurons is via fast excitatory synaptic potentials (EPSPs) and to inhibitory motor neurons via slow EPSPs. We conclude that two rhythm generators regulate segmentation: one drives contractions within segmentation bursts, the other the occurrence of bursts. The latter depends on AHPs in ISNs and feedback to these neurons from contraction of the circular muscle

Mainstreams of Horizontal Gene Exchange in Enterobacteria: Consideration of the Outbreak of Enterohemorrhagic E. coli O104:H4 in Germany in 2011

Escherichia coli O104:H4 caused a severe outbreak in Europe in 2011. The strain TY-2482 sequenced from this outbreak allowed the discovery of its closest relatives but failed to resolve ways in which it originated and evolved. On account of the previous statement, may we expect similar upcoming outbreaks to occur recurrently or spontaneously in the future? The inability to answer these questions shows limitations of the current comparative and evolutionary genomics methods.status: publishe

Rheological parameters of fresh sealing slurries depending on the time of their preparation

Przy wyborze technologii cementowania kolumny rur okładzinowych, zależnie od warunków geologiczno-złożowych i technicznych, niesłychanie ważną rolę odgrywa jakość oraz parametry fizyczne i chemiczne spoiw hydraulicznych, a także właściwości fizykochemicznych świeżego, a później stwardniałego cementu. Zaczyny uszczelniające powinny odznaczać się odpowiednimi właściwościami technologicznymi, aby w najwyższym stopniu spełniały swoje zadanie w otworze. Zaczyny powinny wykazywać ściśle określony czas wiązania, powinny mieć dobrą przetłaczalność przez cały czas trwania zabiegu cementacyjnego. Ich właściwości reologiczne oraz technologiczne powinny odznaczać się minimalną zmiennością pod wpływem dużych zmian temperatur oraz ciśnienia jakie panują w warunkach otworowych na znacznych głębokościach. Parametry reologiczne świeżego zaczynu uszczelniającego, regulowane poprzez wszelkiego rodzaju dodatki i domieszki, powinny zapewnić skuteczne wytłoczenie płuczki wiertniczej z przestrzeni pierścieniowej otworu wiertniczego. W artykule przedstawiono wyniki badań wpływu czasu cementowania na zmiany właściwości reologicznych zaczynów uszczelniających sporządzanych na osnowie cementu portlandzkiego CEM I 42,5 R. Pomiary wykonywane były w różnych odstępach czasowych. Przez pierwsze dwie godziny od dokładnego wymieszania zaczynów pomiary odbywały się co pół godziny, każdy następny - co godzinę. Maksymalny czas, po którym dokonywano pomiaru to 6 godzin. Badania obejmowały pomiar własności reologicznych zaczynów za pomocą lepkościomierza typu Chan 35, kubka Forda nr 4 oraz rozlewności za pomocą ściętego stożka AzNII.The selection of casing cementation technology in view of geologic, reservoir and technological conditions is largely conditioned ob. the physical and chemical parameters of hydraulic binders and also physicochemical properties of fresh and then set cement. Sealing slurries should have suitable technological properties, enabling their optimum operation in the borehole. Sealing slurries should have a strictly defined time of setting, good pumpability over the cementation process. Their rheological and technological properties should have little variability under high temperature and pressure changes in deep borehole conditions. Rheological parameters of fresh sealing slurry, regulated by all kinds of additives and admixtures should guarantee efficient pumping out of drilling mud from the annular space. The results of analyses of cementation time on changes of rheological parameters of sealing slurries based on Portland cement CEM I 42,5 R are presented in the paper. Measurements were performed in various spans of time. Over the first two hours after thorough mixing of the slurry, the measurements were made every half an hour, then every hour. The maximum time after which the measurements were made was 6 hrs. The investigations covered rheological properties of slurries with a viscometer Chan 35, Ford cup no. 4 and fluidity with a truncated cone AzNII

NOx and SO2 emission during oxy-coal combustion

The paper presents results of coal behaviour during combustion in oxy-fuel atmosphere. The experiment was performed using 3 meter long Entrained Flow Reactor and 1 meter long Drop Tube Reactor. Three hard coals and two lignites were analysed in order to investigate NOx, SO2 emission and fly ash burnout. The measurements were performed along and at the outlet of a combustion chamber for one– and two – stage combustion. In the second stage of the experiment, kinetic parameters for nitrogen evolution during combustion in oxy – fuel and air were calculated and the division of nitrogen into the volatile matter and the char was measured. The conducted experiment showed that emissions in oxy – fuel are lower than those in air

The dynamic nature of netrin-1 and the structural basis for glycosaminoglycan fragment-induced filament formation

Netrin-1 is a bifunctional chemotropic guidance cue that plays key roles in diverse cellular processes including axon pathfinding, cell migration, adhesion, differentiation, and survival. Here, we present a molecular understanding of netrin-1 mediated interactions with glycosaminoglycan chains of diverse heparan sulfate proteoglycans (HSPGs) and short heparin oligosaccharides. Whereas interactions with HSPGs act as platform to co-localise netrin-1 close to the cell surface, heparin oligosaccharides have a significant impact on the highly dynamic behaviour of netrin-1. Remarkably, the monomer-dimer equilibrium of netrin-1 in solution is abolished in the presence of heparin oligosaccharides and replaced with highly hierarchical and distinct super assemblies leading to unique, yet unknown netrin-1 filament formation. In our integrated approach we provide a molecular mechanism for the filament assembly which opens fresh paths towards a molecular understanding of netrin-1 functions