179 research outputs found
Schweinehaltung: Beratung zurzeit dringlicher als Forschung
Mit einer Umfrage unter Biobetrieben mit Schweinhaltung haben die Fachgruppen Beratung und Tiergesundheit des FiBL zu ergrĂŒnden versucht, wo die wichtigsten Probleme in der Zucht und Mast von Bioschweinen liegen und wo Forschungsbedarf besteht. Interessant ist nicht zuletzt die AbhĂ€ngigkeit der Problemlage von der Anzahl gehaltener Tiere. Die meisten der Schwierigkeiten liessen sich mit verbessertem Management lösen oder vermeiden
Expression and regulation of the neutral amino acid transporter B0AT1 in rat small intestine
Absorption of neutral amino acids across the luminal membrane of intestinal enterocytes is mediated by the broad neutral amino acid transporter B0AT1 (SLC6A19). Its intestinal expression depends on co-expression of the membrane-anchored peptidase angiotensin converting enzyme 2 (ACE2) and is additionally enhanced by aminopeptidase N (CD13). We investigated in this study the expression of B0AT1 and its auxiliary peptidases as well as its transport function along the rat small intestine. Additionally, we tested its possible short- and long-term regulation by dietary proteins and amino acids. We showed by immunofluorescence that B0AT1, ACE2 and CD13 co-localize on the luminal membrane of small intestinal villi and by Western blotting that their protein expression increases in distal direction. Furthermore, we observed an elevated transport activity of the neutral amino acid L-isoleucine during the nocturnal active phase compared to the inactive one. Gastric emptying was delayed by intragastric application of an amino acid cocktail but we observed no acute dietary regulation of B0AT1 protein expression and L-isoleucine transport. Investigation of the chronic dietary regulation of B0AT1, ACE2 and CD13 by different diets revealed an increased B0AT1 protein expression under amino acid-supplemented diet in the proximal section but not in the distal one and for ACE2 protein expression a reverse localization of the effect. Dietary regulation for CD13 protein expression was not as distinct as for the two other proteins. Ring uptake experiments showed a tendency for increased L-isoleucine uptake under amino acid-supplemented diet and in vivo L-isoleucine absorption was more efficient under high protein and amino acid-supplemented diet. Additionally, plasma levels of branched-chain amino acids were elevated under high protein and amino acid diet. Taken together, our experiments did not reveal an acute amino acid-induced regulation of B0AT1 but revealed a chronic dietary adaptation mainly restricted to the proximal segment of the small intestine
GlutamateâSerineâGlycine Index: A Novel Potential Biomarker in Pediatric Non-Alcoholic Fatty Liver Disease
Recycling of aromatic amino acids via TAT1 allows efflux of neutral amino acids via LAT2-4F2hc exchanger
The rate of amino acid efflux from individual cells needs to be adapted to cellular demands and plays a central role for the control of extracellular amino acid homeostasis. A particular example of such an outward amino acid transport is the basolateral efflux from transporting epithelial cells located in the small intestine and kidney proximal tubule. Because LAT2-4F2hc (Slc7a8-Slc3a2), the best known basolateral neutral amino acid transporter of these epithelial cells, functions as an obligatory exchanger, we tested whether TAT1 (Slc16a10), the aromatic amino-acid facilitated diffusion transporter, might allow amino acid efflux via this exchanger by recycling its influx substrates. In this study, we show by immunofluorescence that TAT1 and LAT2 indeed colocalize in the early kidney proximal tubule. Using the Xenopus laevis oocytes expression system, we show that l-glutamine is released from oocytes into an amino-acid-free medium only when both transporters are coexpressed. High-performance liquid chromatography analysis reveals that several other neutral amino acids are released as well. The transport function of both TAT1 and LAT2-4F2hc is necessary for this efflux, as coexpression of functionally inactive but surface-expressed mutants is ineffective. Based on negative results of coimmunoprecipitation and crosslinking experiments, the physical interaction of these transporters does not appear to be required. Furthermore, replacement of TAT1 or LAT2-4F2hc by the facilitated diffusion transporter LAT4 or the obligatory exchanger LAT1, respectively, supports similar functional cooperation. Taken together, the results suggest that the aromatic amino acid diffusion pathway TAT1 can control neutral amino acid efflux via neighboring exchanger LAT2-4F2hc, by recycling its aromatic influx substrate
Evidence for a bound on the lifetime of de Sitter space
Recent work has suggested a surprising new upper bound on the lifetime of de
Sitter vacua in string theory. The bound is parametrically longer than the
Hubble time but parametrically shorter than the recurrence time. We investigate
whether the bound is satisfied in a particular class of de Sitter solutions,
the KKLT vacua. Despite the freedom to make the supersymmetry breaking scale
exponentially small, which naively would lead to extremely stable vacua, we
find that the lifetime is always less than about exp(10^(22)) Hubble times, in
agreement with the proposed bound.Comment: 28 page
D6.2: Intermediate Standardisation and Dissemination Activity Report
This report documents the standardisation and dissemination activities performed by the ORPHEUS project consortium from December 2015 to February 2017
Mass-Matching in Higgsless
Modern extra-dimensional Higgsless scenarios rely on a mass-matching between
fermionic and bosonic KK resonances to evade constraints from precision
electroweak measurements. After analyzing all of the Tevatron and LEP bounds on
these so-called Cured Higgsless scenarios, we study their LHC signatures and
explore how to identify the mass-matching mechanism, the key to their
viability. We find singly and pair produced fermionic resonances show up as
clean signals with 2 or 4 leptons and 2 hard jets, while neutral and charged
bosonic resonances are visible in the dilepton and leptonic WZ channels,
respectively. A measurement of the resonance masses from these channels shows
the matching necessary to achieve . Moreover, a large single
production of KK-fermion resonances is a clear indication of compositeness of
SM quarks. Discovery reach is below 10 fb of luminosity for resonances
in the 700 GeV range.Comment: 28 pages, 18 figure
Influence of diabetes mellitus on the mineralization ability of two endodontic materials
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