406 research outputs found
The Rab5âRab11 Endosomal Pathway is Required for BDNF-Induced CREB Transcriptional Regulation in Hippocampal Neurons
Brain-derived neurotrophic factor (BDNF) is a key regulator of the morphology and connectivity of central neurons. We have previously shown that BDNF/TrkB signaling regulates the activity and mobility of the GTPases Rab5 and Rab11, which in turn determine the postendocytic sorting of signaling TrkB receptors. Moreover, decreased Rab5 or Rab11 activity inhibits BDNF-induced dendritic branching. Whether Rab5 or Rab11 activity is important for local events only or for regulating nuclear signaling and gene expression is unknown. Here, we investigated, in rat hippocampal neuronal cultures derived from embryos of unknown sex, whether BDNF-induced signaling cascades are altered when early and recycling endosomes are disrupted by the expression of dominant negative mutants of Rab5 and Rab11. The activity of both Rab5 and Rab11 was required for sustained activity of Erk1/2, nuclear CREB phosphorylation and increased transcription of a BDNF-dependent program of gene expression containing CRE-binding sites, which includes activity-regulated genes such as Arc, Dusp1, c-fos, Egr1, and Egr2 and growth and survival genes such as Atf3 and Gem Based on our results, we propose that early and recycling endosomes provide a platform for the integration of neurotrophic signaling from the plasma membrane to the nucleus in neurons, and this mechanism is likely to regulate neuronal plasticity and survival.SIGNIFICANCE STATEMENTBDNF is a neurotrophic factor that regulates plastic changes in the brain, including dendritic growth. The cellular and molecular mechanisms underlying this process are not completely understood. Our results uncover the cellular requirements that central neurons possess to integrate the plasma membrane to nuclear signaling in neurons. Our results indicate that the endosomal pathway is required for the signaling cascade initiated by BDNF and its receptors at the plasma membrane to modulate BDNF-dependent gene expression and neuronal dendritic growth mediated by the CREB transcription factor. CREB is a key transcription factor regulating circuit development and learning and memory
Influence of Feeding Enzymatically Hydrolyzed Yeast Cell Wall on Growth Performance and Digestive Function of Feedlot Cattle during Periods of Elevated Ambient Temperature.
In experiment 1, eighty crossbred steers (239±15 kg) were used in a 229-d experiment to evaluate the effects of increasing levels of enzymatically hydrolyzed yeast (EHY) cell wall in diets on growth performance feedlot cattle during periods of elevated ambient temperature. Treatments consisted of steam-flaked corn-based diets supplemented to provide 0, 1, 2, or 3 g EHY/hd/d. There were no effects on growth performance during the initial 139-d period. However, from d 139 to harvest, when 24-h temperature humidity index averaged 80, EHY increased dry matter intake (DMI) (linear effect, p<0.01) and average daily gain (ADG) (linear effect, p = 0.01). There were no treatment effects (p>0.10) on carcass characteristics. In experiment 2, four Holstein steers (292±5 kg) with cannulas in the rumen and proximal duodenum were used in a 4Ă4 Latin Square design experiment to evaluate treatments effects on characteristics of ruminal and total tract digestion in steers. There were no treatment effects (p>0.10) on ruminal pH, total volatile fatty acid, molar proportions of acetate, butyrate, or estimated methane production. Supplemental EHY decreased ruminal molar proportion of acetate (p = 0.08), increased molar proportion of propionate (p = 0.09), and decreased acetate:propionate molar ratio (p = 0.07) and estimated ruminal methane production (p = 0.09). It is concluded that supplemental EHY may enhance DMI and ADG of feedlot steers during periods of high ambient temperature. Supplemental EHY may also enhance ruminal fiber digestion and decrease ruminal acetate:propionate molar ratios in feedlot steers fed steam-flaked corn-based finishing diets
APOYO SOCIAL: ELEMENTO CLAVE EN EL AFRONTAMIENTO DE LA ENFERMEDAD CRĂNICA
La tecnologĂa y los avances en la medicina permiten a las personas sobrevivir a enfermedades fatales y con ello a la incidencia de enfermedades crĂłnicas que se constituyen en principal causa de discapacidad. El apoyo social ha demostrado tener una influencia positiva sobre la experiencia del cuidado de las enfermedades crĂłnicas y de los cuidadores familiares. Se describe como âun proceso de interacciĂłn entre personas o grupos de personas, que a travĂ©s del contacto sistemĂĄtico establecen vĂnculos de amistad y de informaciĂłn, recibiendo apoyo material, emocional y afectivo en la soluciĂłn de situaciones cotidianas en momentos de crisisâ.
El presente artĂculo representa la revisiĂłn del concepto de apoyo social desde su origen, señala varias definiciones que expertos han dado al tema y cita ejemplos de su aplicaciĂłn en la investigaciĂłn con contribuciones de la sociologĂa, psicologĂa, medicina y enfermerĂa. Constituye el marco de referencia del estudio de tipo evaluativo que tiene por objetivo determinar la efectividad del apoyo social dado a travĂ©s de una red con tecnologĂa punta a cuidadores familiares de personas con enfermedad crĂłnica en LatinoamĂ©rica
Pulp properties resulting from different pretreatments of wheat straw and their influence on enzymatic hydrolysis rate
Wheat straw was subjected to three different processes prior to saccharification, namely alkaline pulping, natural pulping and autohydrolysis, in order to study their effect on the rate of enzymatic hydrolysis. Parameters like medium concentration, temperature and time have been varied in order to optimize each method. Milling the raw material to a length of 4 mm beforehand showed the best
costâvalue-ratio compared to other grinding methods studied. Before saccharification the pulp can be stored in dried form, leading to a high yield of glucose. Furthermore the relation of pulp properties (i.e. intrinsic viscosity, KLASON-lignin and hemicelluloses content, crystallinity, morphology) to cellulose hydrolysis is discussed
C-reactive protein reference percentiles among pre-adolescent children in Europe based on the IDEFICS study population
OBJECTIVES: C-reactive protein (CRP) is involved in a wide range of diseases. It is a powerful marker for inflammatory processes used for diagnostic and monitoring purposes. We aimed to establish reference values as data on the distribution of serum CRP levels in young European children are scarce.
SUBJECTS: Reference values of high-sensitivity CRP concentrations were calculated for 9855 children aged 2.0-10.9 years, stratified by age and sex. The children were recruited during the population-based European IDEFICS study (Identification and prevention of Dietary-and lifestyle-induced health Effects in Children and infantS) with 18 745 participants recruited from 2007 to 2010.
RESULTS: In 44.1 % of the children, CRP values were below or equal the detection limit of 0.2 mg/l. Median CRP concentrations showed a slight negative age trend in boys and girls, whereas serum CRP values were slightly higher in girls than in boys across all age groups.
CONCLUSIONS: Our population-based reference values of CRP may guide paediatric practice as elevated values may require further investigation or treatment. Therefore, the presented reference values represent a basis for clinical evaluation and for future research on risk assessment of diseases associated with increased CRP levels among children
Influence of the Temperature and the Genotype of the HSP90AA1 Gene over Sperm Chromatin Stability in Manchega Rams
The present study addresses the effect of heat stress on males' reproduction ability. For that, we have evaluated the sperm DNA fragmentation (DFI) by SCSA of ejaculates incubated at 37°C during 0, 24 and 48 hours after its collection, as a way to mimic the temperature circumstances to which spermatozoa will be subject to in the ewe uterus. The effects of temperature and temperature-humidity index (THI) from day 60 prior collection to the date of semen collection on DFI were examined. To better understand the causes determining the sensitivity of spermatozoa to heat, this study was conducted in 60 males with alternative genotypes for the SNP G/Câ660 of the HSP90AA1 promoter, which encode for the Hsp90α protein. The Hsp90α protein predominates in the brain and testis, and its role in spermatogenesis has been described in several species. Ridge regression analyses showed that days 29 to 35 and 7 to 14 before sperm collection (bsc) were the most critical regarding the effect of heat stress over DFI values. Mixed model analyses revealed that DFI increases over a threshold of 30°C for maximum temperature and 22 for THI at days 29 to 35 and 7 to 14 bsc only in animals carrying the GGâ660 genotype. The period 29â35 bsc coincide with the meiosis I process for which the effect of the Hsp90α has been described in mice. The period 7â14 bsc may correspond with later stages of the meiosis II and early stages of epididymal maturation in which the replacement of histones by protamines occurs. Because of GGâ660 genotype has been associated to lower levels of HSP90AA1 expression, suboptimal amounts of HSP90AA1 mRNA in GGâ660 animals under heat stress conditions make spermatozoa DNA more susceptible to be fragmented. Thus, selecting against the GGâ660 genotype could decrease the DNA fragmentation and spermatozoa thermal susceptibility in the heat season, and its putative subsequent fertility gainsPublishe
Observation of associated near-side and away-side long-range correlations in âsNN=5.02ââTeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (ÎÏ) and pseudorapidity (Îη) are measured in âsNN=5.02ââTeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1ââÎŒb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Îη|<5) ânear-sideâ (ÎÏâŒ0) correlation that grows rapidly with increasing ÎŁETPb. A long-range âaway-sideâ (ÎÏâŒÏ) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Îη and ÎÏ) and ÎŁETPb dependence. The resultant ÎÏ correlation is approximately symmetric about Ï/2, and is consistent with a dominant cosâĄ2ÎÏ modulation for all ÎŁETPb ranges and particle pT
Non-invasive intravital imaging of cellular differentiation with a bright red-excitable fluorescent protein
A method for non-invasive visualization of genetically labelled cells in animal disease
models with micron-level resolution would greatly facilitate development of cell-based
therapies. Imaging of fluorescent proteins (FPs) using red excitation light in the âoptical
windowâ above 600 nm is one potential method for visualizing implanted cells. However,
previous efforts to engineer FPs with peak excitation beyond 600 nm have resulted in
undesirable reductions in brightness. Here we report three new red-excitable monomeric FPs obtained by structure-guided mutagenesis of mNeptune, previously the brightest monomeric FP when excited beyond 600 nm. Two of these, mNeptune2 and mNeptune2.5, demonstrate improved maturation and brighter fluorescence, while the third, mCardinal, has a red-shifted excitation spectrum without reduction in brightness. We show that mCardinal can be used to non-invasively and longitudinally visualize the differentiation of myoblasts and stem cells into myocytes in living mice with high anatomical detail
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Assessment of the anthelmintic activity of medicinal plant extracts and purified condensed tannins against free-living and parasitic stages of Oesophagostomum dentatum
Background: Plant-derived condensed tannins (CT) show promise as a complementary option to treat gastrointestinal helminth infections, thus reducing reliance on synthetic anthelmintic drugs. Most studies on the anthelmintic effects of CT have been conducted on parasites of ruminant livestock. Oesophagostomum dentatum is an economically important parasite of pigs, as well as serving as a useful laboratory model of helminth parasites due to the ability to culture it in vitro for long periods through several life-cycle stages. Here, we investigated the anthelmintic effects of CT on multiple life-cycles stages of O. dentatum.
Methods: Extracts and purified fractions were prepared from five plants containing CT and analysed by HPLC-MS. Anthelmintic activity was assessed at five different stages of the O. dentatum life cycle; the development of eggs to infective third-stage larvae (L3), the parasitic L3 stage, the moult from L3 to fourth-stage larvae (L4), the L4 stage and the adult stage.
Results: Free-living larvae of O. dentatum were highly susceptible to all five plant extracts. In contrast, only two of the five extracts had activity against L3, as evidenced by migration inhibition assays, whilst three of the five extracts inhibited the moulting of L3 to L4. All five extracts reduced the motility of L4, and the motility of adult worms exposed to a CT-rich extract derived from hazelnut skins was strongly inhibited, with electron microscopy demonstrating direct damage to the worm cuticle and hypodermis. Purified CT fractions retained anthelmintic activity, and depletion of CT from extracts by pre-incubation in polyvinylpolypyrrolidone removed anthelmintic effects, strongly suggesting CT as the active molecules.
Conclusions: These results suggest that CT may have promise as an alternative parasite control option for O. dentatum in pigs, particularly against adult stages. Moreover, our results demonstrate a varied susceptibility of different life-cycle stages of the same parasite to CT, which may offer an insight into the anthelmintic mechanisms of these commonly found plant compounds
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