287 research outputs found
Type of hormonal treatment administered to induce vitellogenesis in European eel influences biochemical composition of eggs and yolk-sac larvae
Egg biochemical composition is among the main factors affecting offspring quality and survival during the yolk-sac stage, when larvae depend exclusively on yolk nutrients. These nutrients are primarily embedded in the developing oocytes during vitellogenesis. In aquaculture, assisted reproduction procedures may be applied enabling gamete production. For the European eel (Anguilla anguilla), reproductive treatment involves administration of pituitary extracts from carp (CPE) or salmon (SPE) to induce and sustain vitellogenesis. In the present study, we compared the influence of CPE and SPE treatments on offspring quality and composition as well as nutrient utilization during the yolk-sac stage. Thus, dry weight, proximal composition (total lipid, total protein), free amino acids, and fatty acids were assessed in eggs and larvae throughout the yolk-sac stage, where body and oil-droplet area were measured to estimate growth rate, oil-droplet utilization, and oil-droplet utilization efficiency. The results showed that CPE females spawned eggs with higher lipid and free amino acid contents. However, SPE females produced more buoyant eggs with higher fertilization rate as well as larger larvae with more energy reserves (estimated as oil-droplet area). Overall, general patterns of nutrient utilization were detected, such as the amount of total lipid and monounsaturated fatty acids decreasing from the egg stage and throughout the yolk-sac larval stage. On the contrary, essential fatty acids and free amino acids were retained. Notably, towards the end of the yolk-sac stage, the proximal composition and biometry of surviving larvae, from both treatments, were similar
A Compact Gas Cerenkov Detector with Novel Optics
We discuss the design and performance of a threshold Cerenkov counter for
identification of charged hadrons. The radiator is pressurized gas, which is
contained in thin-walled cylindrical modules. A mirror system of novel design
transports Cerenkov photons to photomultiplier tubes. This system is compact,
contains relatively little material, and has a large fraction of active volume.
A prototype of a module designed for the proposed CLEO III detector has been
studied using cosmic rays. Results from these studies show good agreement with
a detailed Monte Carlo simulation of the module and indicate that it should
achieve separation of pions and kaons at the 2.5-3.0sigma level in the momentum
range 0.8-2.8 GeV/c. We predict performance for specific physics analyses using
a GEANT-based simulation package.Comment: Submitted to NIM. 23 pages, 11 postscript figures. Postscript file is
also available at http://w4.lns.cornell.edu/public/CLNS/199
Assessment of lipid uptake and fatty acid metabolism of European eel larvae (Anguilla anguilla) determined by 14C in vivo incubation
Knowledge on dietary nutrient requirements of first-feeding European eel larvae (Anguilla anguilla) is very limited. This study provides first ever information on in vivo lipid uptake and fatty acid (FA) metabolism of European pre-leptocephalus eel larvae and advances directions for dietary lipid and FA inclusions. The in vivo capability of eel larvae to incorporate and metabolize unsaturated fatty acids was tested on larvae at different ontogenetic stages (4, 8 and 12 days post hatch, DPH). Larvae were incubated in 10 mL flat-bottom tissue culture plates, with [1-14C]-labelled FA (18:2n-6, ALA; 18:3n-3, LA; 20:4n-6, ARA and 20:5n-3, EPA) directly added to seawater. The capability of the larvae for de-acylation and re-acylation of [1-14C]arachidonic acid (ARA), initially bound to phosphatidylcholine (PC) and phosphatidylethanolamine (PE), was also investigated. In all cases, control incubations without any radiolabelled substrate were performed for further lipid analysis. The results revealed that direct incubation with 14C-labelled FA is a feasible method to investigate in vivo FA and phospholipids metabolism of pre-leptocephalus stages of the European eel. No enzymatic elongation/desaturation activity towards [1-14C]C18 or [1-14C]C20 FA was detected. Consequently, ARA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) must be considered essential FA and thus provided firstly through female broodstock and later through diet at least during the first-feeding stage. Pre-leptocephalus larvae display a high capacity to remodel dietary phospholipids with a preferential esterification of all FA substrates into PC. The unexpectedly high esterification rate of [1-14C] ARA into PC and PE is supported by the individual FA profiles of the larval phospholipids. The high levels of ARA present in the European eel larvae denotes its physiological relevance for this species. It is therefore essential to consider this FA as particularly important when designing suitable broodstock – or first-feeding diets for this species
Ab-initio study of BaTiO3 surfaces
We have carried out first-principles total-energy calculations of (001)
surfaces of the tetragonal and cubic phases of BaTiO3. Both BaO-terminated
(type I) and TiO2-terminated (type II) surfaces are considered, and the atomic
configurations have been fully relaxed. We found no deep-gap surface states for
any of the surfaces, in agreement with previous theoretical studies. However,
the gap is reduced for the type-II surface, especially in the cubic phase. The
surface relaxation energies are found to be substantial, i.e., many times
larger than the bulk ferroelectric well depth. Nevertheless, the influence of
the surface upon the ferroelectric order parameter is modest; we find only a
small enhancement of the ferroelectricity near the surface.Comment: 8 pages, two-column style with 4 postscript figures embedded. Uses
REVTEX and epsf macros. Also available at
http://www.physics.rutgers.edu/~dhv/preprints/index.html#pad_sur
Fibrosis of extracellular matrix is related to the duration of the disease but is unrelated to the dynamics of collagen metabolism in dilated cardiomyopathy
Background Fibrosis of extracellular matrix (ECM) in
dilated cardiomyopathy (DCM) corresponds to the
myocardial over-production of various types of collagens.
However, mechanism of this process is poorly understood.
Objective To investigate whether enhanced metabolism of
ECM occur in DCM.
Methods Seventy consecutive DCM patients (pts)
(48 ± 12.1 years, EF 24.4 ± 7.4 %) and 20 healthy volunteers
were studied. Based on symptoms duration, pts
were divided into new-onset (n = 35, 6 months) and
chronic DCM (n = 35, >6 months). Markers of collagen
type I and III synthesis-procollagen type I carboxy- and
amino-terminal peptides (PICP and PINP) and procollagen
type III carboxy- and amino-terminal peptides (PIIICP and
PIIINP), collagen 1 (col-1), ECM metabolism controlling
factors-tumor growth factor beta-1 (TGF1-b), connective
tissue growth factor (CTGF), and ECM degradation
enzymes-matrix metalloproteinases (MMP-2, MMP-9)
and their tissue inhibitor (TIMP-1) were measured in serum. All pts underwent right ventricular endomyocardial
biopsy to study ECM fibrosis.
Results The presence of fibrosis was detected in 24
(34.3 %) pts and was more prevalent in chronic DCM
[17 (48.6 %) vs. 7 (20 %), p\0.01]. The levels of
PIIINP [4.41 (2.17-6.08) vs. 3.32 (1.69-5.02) ng/ml,
p\0.001], CTGF [3.82 (0.48-23.87) vs. 2.37
(0.51-25.32) ng/ml, p\0.01], MMP-2 [6.06 (2.72-14.8)
vs. 4.43 (2.27=7.4) ng/ml, p\0.001], MMP-9 [1.98
(0.28-9.25) vs. 1.01 (0.29-3.59) ng/ml, p\0.002)], and
TIMP-1 [15.29 (1.8-36.17) vs. 2.61 (1.65-24.09) ng/ml,
p\0.004] were significantly higher in DCM, whereas
levels of col-1 [57.7 (23.1-233.4) vs. 159.4 (31.2-512.9)
pg/ml, p\0.001] were significantly lower in DCM
compared to controls. There were no differences in all
measured serum markers of ECM metabolism between
newonset and chronic DCM and as well as fibrosis
positive and negative pts. Fibrosis was weakly correlated
only with the duration of DCM (r = 0.23, p\0.05),
however, not a single serum marker of fibrosis correlated
with fibrosis. Neither unadjusted nor adjusted models,
constructed from serum markers of ECM metabolism,
predicted the probability of myocardial fibrosis.
Conclusions Dynamics of ECM turnover in DCM is high,
which is reflected by the increased levels CTGF and
degradation enzymes. Synthesis of collagen type III prevailed
over collagen type I. ECM metabolism was not
different in DCM regardless of the duration of the disease
and status of myocardial fibrosis. Serum markers of ECM
metabolism were found not to be useful for the prediction
of myocardial fibrosis in DCM
Electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ
We study the electronic structure of the quasi-one-dimensional organic
conductor TTF-TCNQ by means of density-functional band theory, Hubbard model
calculations, and angle-resolved photoelectron spectroscopy (ARPES). The
experimental spectra reveal significant quantitative and qualitative
discrepancies to band theory. We demonstrate that the dispersive behavior as
well as the temperature-dependence of the spectra can be consistently explained
by the finite-energy physics of the one-dimensional Hubbard model at metallic
doping. The model description can even be made quantitative, if one accounts
for an enhanced hopping integral at the surface, most likely caused by a
relaxation of the topmost molecular layer. Within this interpretation the ARPES
data provide spectroscopic evidence for the existence of spin-charge separation
on an energy scale of the conduction band width. The failure of the
one-dimensional Hubbard model for the {\it low-energy} spectral behavior is
attributed to interchain coupling and the additional effect of electron-phonon
interaction.Comment: 18 pages, 9 figure
Assessment of testis development during induced spermatogenesis in the European eel Anguilla anguilla
Temperature induced variation in gene expression of thyroid hormone receptors and deiodinases of European eel (Anguilla anguilla) larvae
Thyroid hormones (THs) are key regulators of growth, development, and metabolism in vertebrates and influence early life development of fish. TH is produced in the thyroid gland (or thyroid follicles) mainly as T4 (thyroxine), which is metabolized to T3 (3, 5, 3’-triiodothyronine) and T2 (3, 5-diiodothyronine) by deiodinase (DIO) enzymes in peripheral tissues. The action of these hormones is mostly exerted by binding to a specific nuclear thyroid hormone receptor (THR). In this study, we i) cloned and characterized thr sequences, ii) investigated the expression pattern of the different subtypes of thrs and dios, and iii) studied how temperature affects the expression ofthose genes in artificially produced early life history stages of European eel (Anguilla anguilla), reared in different thermal regimes (16, 18, 20 and 22°C) from hatch until first-feeding. We identified 2 subtypes of thr (thrα and thrβ) with 2 isoforms each (thrαA, thrαB, thrβA, thrβB) and 3 subtypes of deiodinases (dio1, dio2, dio3). All thr genes identified showed high similarity to the closely related Japanese eel (Anguilla japonica). We found that all genes investigated in this study were affected by larval age (in real time or at specific developmental stages), temperature, and/or their interaction. More specifically, the warmer the temperature the earlier the expression response of a specific target gene. In real time, the expression profiles appeared very similar and only shifted with temperature. In developmental time, gene expression of all genes differed across selected developmental stages, such as at hatch, during teeth formation or at first-feeding. Thus, we demonstrate that the expression of thrs and dios show sensitivity to temperature and are involved in and during early life development of European eel
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