930 resultados para Alexander I, Pope, d. 115 or 6.
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In unstimulated cells, proteins of the nuclear factor kappaB (NF-kappaB) transcription factor family are sequestered in the cytoplasm through interactions with IkappaB inhibitor proteins. Tumor necrosis factor alpha (TNF-alpha) activates the degradation of IkappaB-alpha and the nuclear import of cytoplasmic NF-kappaB. Nuclear localization of numerous cellular proteins is mediated by the ability of the cytoskeleton, usually microtubules, to direct their perinuclear accumulation. In a former study we have shown that activated NF-kappaB rapidly moves from distal processes in neurons towards the nucleus. The fast transport rate suggests the involvement of motor proteins in the transport of NF-kappaB. Here we address the question how NF-kappaB arrives at the nuclear membrane before import in non-neuronal cells, i.e., by diffusion alone or with the help of active transport mechanisms. Using confocal microscopy imaging and analysis of nuclear protein extracts, we show that NF-kappaB movement through the cytoplasm to the nucleus is independent of the cytoskeleton, in the three cell lines investigated here. Additionally we demonstrate that NF-kappaB p65 is not associated with the dynein/dynactin molecular motor complex. We propose that cells utilize two distinct mechanisms of NF-kappaB transport: (1) signaling via diffusion over short distances in non-neuronal cells and (2) transport via motor proteins that move along the cytoskeleton in neuronal processes where the distances between sites of NF-kappaB activation and nucleus can be vast.
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The type and quantity of fertilizer supplied to a crop will differ between organic and conventional farming practices. Altering the type of fertilizer a plant is provided with can influence a plant’s foliar nitrogen levels, as well as the composition and concentration of defence compounds, such as glucosinolates. Many natural enemies of insect herbivores can respond to headspace volatiles emitted by the herbivores’ host plant in response to herbivory. We propose that manipulating fertilizer type may also influence the headspace volatile profiles of plants, and as a result, the tritrophic interactions that occur between plants, their insect pests and those pests’ natural enemies. Here, we investigate a tritrophic system consisting of cabbage plants, Brassica oleracea, a parasitoid, Diaeretiella rapae, and one of its hosts, the specialist cabbage aphid Brevicoryne brassicae. Brassica oleracea plants were provided with either no additional fertilization or one of three types of fertilizer: Nitram (ammonium nitrate), John Innes base or organic chicken manure. We investigated whether these changes would alter the rate of parasitism of aphids on those plants and whether any differences in parasitism could be explained by differences in attractivity of the plants to D. rapae or attack rate of aphids by D. rapae. In free-choice experiments, there were significant differences in the percentage of B. brassicae parasitized by D. rapae between B. oleracea plants grown in different fertilizer treatments. In a series of dual-choice Y-tube olfactometry experiments, D. rapae females discriminated between B. brassicae-infested and undamaged plants, but parasitoids did not discriminate between similarly infested plants grown in different fertilizer treatments. Correspondingly, in attack rate experiments, there were no differences in the rate that D. rapae attacked B. brassicae on B. oleracea plants grown in different fertilizer treatments. These findings are of direct relevance to sustainable and conventional farming practices.
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Combined micropaleontological and geochemical analyses of the high-sedimentation gravity core M-4G provided new centennial-scale paleoceanographic data for sapropel S1 deposition in the NE Aegean Sea during the Holocene Climatic Optimum. Sapropel layer S1a (10.2–8.0 ka) was deposited in dysoxic to oxic bottom waters characterized by a high abundance of benthic foraminiferal species tolerating surface sediment and/or pore water oxygen depletion (e.g., Chilostomella mediterranensis, Globobulimina affinis), and the presence of Uvigerina mediterranea, which thrives in oxic mesotrophic-eutrophic environments. Preservation of organic matter (OM) is inferred based on high organic carbon as well as loliolide and isololiolide contents, while the biomarker record and the abundances of eutrophic planktonic foraminifera document enhanced productivity. High inputs of terrigenous OM are attributed to north Aegean borderland riverine inputs. Both alkenone-based sea surface temperatures (SSTs) and δO18G. bulloides records indicate cooling at 8.2 ka (S1a) and ~7.8 ka (S1 interruption). Sapropelic layer S1b (7.7–6.4 ka) is characterized by rather oxic conditions; abundances of foraminiferal species tolerant to oxygen depletion are very low compared with the U. mediterranea rise. Strongly fluctuating SSTs demonstrate repeated cooling and associated dense water formation, with a major event at 7.4 ka followed by cold spells at 7.0, 6.8, and 6.5 ka. The prominent rise of the carbon preference index within the S1b layer indicates the delivery of less degraded terrestrial OM. The increase of algal biomarkers, labile OM-feeding foraminifera and eutrophic planktonic species pinpoints an enhanced in situ marine productivity, promoted by more efficient vertical convection due to repeated cold events. The associated contributions of labile marine OM along with fresher terrestrial OM inputs after ~7.7 ka imply sources alternative/additional to the north Aegean riverine borderland sources for the influx of organic matter in the south Limnos Basin, plausibly related to the inflow of highly productive Marmara/Black Sea waters.
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Leite-Dellova DC, Malnic G, Mello-Aires M. Genomic and non-genomic stimulatory effect of aldosterone on H(+)-ATPase in proximal S3 segments. Am J Physiol Renal Physiol 300: F682-F691, 2011. First published December 29, 2010; doi:10.1152/ajprenal.00172.2010.-The genomic and nongenomic effects of aldosterone on the intracellular pH recovery rate (pHirr) via H(-)(+)ATPase and on cytosolic free calcium concentration ([Ca(2+)](i)) were investigated in isolated proximal S3 segments of rats during superfusion with an Na(+)-free solution, by using the fluorescent probes BCECF-AM and FLUO-4-AM, respectively. The pHirr, after cellular acidification with a NH(4)Cl pulse, was 0.064 +/- 0.003 pH units/min (n = 17/74) and was abolished with concanamycin. Aldosterone (10(-12), 10(-10),10(-8), or 10(-6) M with 1-h or 15- or 2-min preincubation) increased the pHirr. The baseline [Ca(2+)](i) was 103 +/- 2 nM (n = 58). After 1 min of aldosterone preincubation, there was a transient and dose-dependent increase in [Ca(2+)](i) and after 6-min preincubation there was a new increase in [Ca(2+)](i) that persisted after 1 h. Spironolactone [mineralocorticoid (MR) antagonist], actinomycin D, or cycloheximide did not affect the effects of aldosterone (15- or 2-min preincubation) on pHirr and on [Ca(2+)](i) but inhibited the effects of aldosterone (1-h preincubation) on these parameters. RU 486 [glucocorticoid (GR) antagonist] and dimethyl-BAPTA (Ca(2+) chelator) prevented the effect of aldosterone on both parameters. The data indicate a genomic (1 h, via MR) and a nongenomic action (15 or 2 min, probably via GR) on the H(+)-ATPase and on [Ca(2+)](i). The results are compatible with stimulation of the H(+)-ATPase by increases in [Ca(2+)](i) (at 10(-12)-10(-6) M aldosterone) and inhibition of the H(+)-ATPase by decreases in [Ca(2+)](i) (at 10(-12) or 10(-6) M aldosterone plus RU 486).
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Ekens (Quercus robur) nordgräns sägs gå vid Dalälven, Limes Norrlandicus – den biologiska Norrlandsgränsen. Ludvikabygden skiljer sig naturgeografiskt och topografiskt från övriga Dalarna och tillhör Mälarens avrinningsområde. Trakten runt sjön Väsman har ett varmare klimat och fler soltimmar än den övriga bygden. För mellan 5.000-8.000 år sedan vandrade eken in i Sverige efter den senaste istiden. Det tog 3.000 år för den att sprida sig över hela Sverige som då hade en medeltemperatur 2-3? högre än idag.Ekens vegetationsperiod – när dygnsmedeltemperaturen överstiger 5? – är ca 7 månader för att ekollonen skall bli groningsdugliga och därmed kunna föröka sig naturligt. I Ludvikatrakten är vegetationsperioden ca 6 månader. Dalarnas skogar består av ? 1% ek. Årsmedeltemperaturen har i Mellansverige ökat ungefär 1? de senaste 30 åren. I framtiden får vi räkna med temperaturhöjningar på mellan 2-6? beroende på hur stort utsläpp som sker till atmosfären. Detta innebär att vi på dessa breddgrader får ett klimat liknande det i Centraleuropa med längre odlingssäsong. Det innebär också ökande skador på skog och växtlighet samt fler och mer extrema väderväxlingar.Syftet med den här undersökningen är att se om etablering av ek har skett i Ludvikatrakten de senaste decennierna samt vilka faktorer som kan påverka detta. Två separata områden om vardera 1,0 ha undersöktes. På område 1 i nordvästsluttning registrerades 20 exemplar av ek. På område 2 i västsluttning registrerades 28 exemplar av ek. Gamla ekar är en nyckelbiotop för sällsynta insekter och kryptogamer. Ek är stormfast p g a dess djupa rotsystem. Blandskog motverkar parasit-, insektsangrepp och rotröta samt gynnar biologisk mångfald och etablering av fältskikt. Ekens virke är dessutom eftertraktat då det är hårt och slitstarkt.
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Denna studie syftar till att undersöka tidigare forsknings syn på lärande i autentiska situationerinom undervisning i naturvetenskap för årskurs 4-6. Detta syfte besvaras genom att undersökavilka möjligheter och utmaningar som finns med lärande i autentiska situationer enligt tidigareforskningsstudier. Studien har en kvalitativ ansats med systematisk litteraturstudie som metod.Samtlig inkluderad litteratur är vetenskapliga artiklar som genomgått peer review och harinkluderats efter sökningar i databaserna Summon samt Eric (Ebsco). Dessa har kritiskt granskatsutifrån uppsatta kriterier och resultatet har analyserats, sammanställts och diskuterats. Studienvisar att undervisning inom de naturorienterande ämnena som bygger på lärande i autentiskasituationer bland annat kan bidra till att undervisningen kopplas till elevernas vardag och denkomplexa verklighet som skolan ska förbereda dem för. Dessutom beskrivs en positiv effekt påelevernas motivation för att lära naturvetenskap och ökad effektivitet i elevernaskunskapsinhämtning i naturvetenskapsundervisningen. Därutöver visar studien att det skapadesett större elevinflytande och ökat egenansvar i undervisningen. Studien visar att anledningar till attundervisning i autentiska situationer kan upplevas som problematisk är bristande resurser ochverktyg, en ökad arbetsbelastning och svårigheter att välja lämpliga lärandesituationer samt att detkrockar med den skolkultur som råder.
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Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES)
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Avaliaram-se o efeito do IGF-I na maturação in vitro (MIV) (experimento I) e no desenvolvimento embrionário (DE) (experimento II) de oócitos bovinos fecundados in vitro, quanto às taxas de clivagem (TC), de blastocistos (TB) e de eclosão (TE). Para MIV, complexos cumulus-oócitos imaturos foram cultivados em meio TCM-199 suplementado com HEPES, bicarbonato e piruvato de sódio, aditivos, soro fetal bovino (meio B-199) e gonadotrofinas 14U/ml de PMSG e 7U/ml de hCG). Para o desenvolvimento embrionário, os oócitos/zigotos foram cultivados em meio B-199 com células epiteliais do oviduto bovino em suspensão sob óleo de silicone. As condições de cultivo in vitro para ambos os experimentos seguiram os tratamentos: 1- meio B-199 + 200 ng/ml IGF-I; 2- B-199 + 100 ng/ml IGF-I; 3- B-199 + 50 ng/ml IGF-I; 4- B-199 + 10 ng/ml IGF-I; 5- B-199 + 0 ng/ml IGF-I. Todas as culturas foram realizadas a 38,5° C em atmosfera com 5% de CO2 e os dados foram analisados pelo teste do qui-quadrado. No experimento I, não houve diferença (P>0,05) entre os tratamentos quanto às TC, TB e TE, quando o meio de MIV foi suplementado com IGF-I. No experimento II, a adição de IGF-I ao meio de DE resultou em aumento na TC (P<0,05) mas não influenciou a TB e a TE. A adição de 200 ng/ml de IGF-I ao meio DE melhorou a TC (71,1%) quando comparada com a TC dos grupos de 100 ng/ml de IGF-I (57,6%) ou controle (56,7%), entretanto não houve diferença quando comparada com a dos grupos de 50 ng/ml (69,4%) ou 10 ng/ml (73,1%) de IGF-I. Não houve efeito benéfico na adição de 10 a 200 ng/ml de IGF-I nos meios de MIV e de DE com relação ao desenvolvimento de embriões produzidos a partir de oócitos maturados e fecundados in vitro.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Helicobacter pylori (H. pylori) is believed to dispose carriers to gastric cancer by inducing chronic inflammation. The inflammatory processes may result in the generation of reactive oxygen and nitrogen species that damage DNA. In this study, we investigated the relationships between DNA damage in the gastric mucosa and cogA, vocA, and iceA genotypes of H. pylori. The study was conducted with biopsies from the gastric antrum and corpus of 98 H. pylori-infected and 26 uninfected control patients. H. pylori genotypes were determined by PCR and DNA damage was measured in gastric mucosal cells by the Comet assay (single cell gel electrophoresis). All patients were nonsmokers, not abusing alcohol, and not using prescription or recreational drugs. Levels of DNA damage were significantly higher (P < 0.0001) in the H. pylori-infected patients than in uninfected patients. In comparison with the level of DNA damage in the uninfected controls, the extent of DNA damage in both the antrum (OR = 8.45; 95% Cl 2.33-37.72) and the corpus (OR 6.55; 95% Cl 2.52-17.72) was related to infection by cagA(+)/vocAs1m1 and iceA1 strains. The results indicate that the genotype of H. pylori is related to the amount of DNA damage in the gastric mucosa. These genotypes could serve as biomarkers for the risk of extensive DNA damage and possibly gastric cancer. (C) 2004 Wiley-Liss, Inc.
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1. This experiment was carried out to evaluate the productive and physiological consequences of a slight but long term food restriction of male broiler chickens from 2 commercial strains.2. Cobb-500 and Ross chickens were submitted to a 20% food restriction from 8 to 21 d of age. Strain, food programme and their interactive effects were analysed in terms of consequences upon performance, mortality, incidence of sudden death syndrome (SDS) and ascites syndrome (AS), index of right cardiac hypertrophy and plasma concentrations of hormones related to metabolism and growth (T-3, T-4, T-3:T-4 ratio, IGF-I and GH).3. Although some catch-up growth was observed by refeeding previously restricted birds after 22 d of rearing, food restriction decreased (P less than or equal to 0.05) body weight at market age (42 d) irrespective of the strain, but improved (P less than or equal to 0.05) food conversion.4. The incidence of mortality was not high in non-restricted birds but SDS and AS caused more than 50% of deaths. Hypertrophic cardiac index was observed in chickens of both strains after 4 weeks of age and was higher in ad libitum fed birds.5. During the period of food restriction, plasma T-3 and IGF-I concentrations decreased whereas plasma T-4 and GH concentrations increased compared to those of the age-matched ad libitum fed counterparts. During the subsequent ad libitum feeding period, few differences in circulating hormone concentrations were observed, except for the higher mean CH litres in previously food-restricted chickens at 35 d of age.6. These results indicate that even a non-severe food restriction negatively affects body weight of 42-d-old male broilers but these are benefits with improved food efficiency and diminished mortality from metabolic disturbances. The hormone results suggest that the degree of food restriction applied was not severe because there was a very fast adaptive response with small and transient alterations in T-3, T-4 and GH plasma concentrations during the period of compensatory growth.
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The purpose of this study was to evaluate the color stability of a maxillofacial elastomer with the addition of a nanoparticle pigment and/or an opacifier submitted to chemical disinfection and artificial aging. Specimens were divided into four groups (n = 30): group I: silicone without pigment or opacifier, group II: ceramic powder pigment, group III: Barium sulfate (BaSO(4)) opacifier, and group IV: ceramic powder and BaSO(4) opacifier. Specimens of each group (n = 10) were disinfected with effervescent tablets, neutral soap, or 4% chlorhexidine gluconate. Disinfection was done three times a week during two months. Afterward, specimens were submitted to different periods of artificial aging. Color evaluation was initially done, after 60 days (disinfection period) and after 252, 504, and 1008 h of artificial aging with aid of a reflection spectrophotometer. Data were analyzed by three-way ANOVA and Tukey test (alpha = 0.05). The isolated factor disinfection did not statistically influence the values of color stability among groups. The association between pigment and BaSO(4) opacifier (GIV) was more stable in relationship to color change (Delta E). All values of Delta E obtained, independent of the disinfectant and the period of artificial aging, were considered acceptable in agreement with the norms presented in literature. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3625401]
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Polyanionic substances are known to inhibit the myotoxic effects of some crotalide snake venoms. Bothropstoxin-I (BthTX-I), a basic Lys49 phospholipase (PLA(2)) homologue from Bothrops jararacussu venom, besides inducing muscle damage, also promotes the blockade of both directly and indirectly evoked contractions in mouse neuromuscular preparation. In this work, we evaluated the ability of suramin, a polysulfonated naphtylurea derivative, to antagonize the myotoxic and the paralyzing activities of BthTX-I on mice neuromuscular junction in vitro. Myotoxicity was assessed by light and electronic microscopic analysis of extensor digitorum longus (EDL) muscles; paralyzing activity was evaluated through the recording of both directly and indirectly evoked contractions of phrenic-diaphragm (PD) preparations. BthTX-I (1 muM) alone, or pre-incubated with suramin (10 muM) at 37degreesC for 15 min was added to the preparations for 120 min. BthTX-I induced histological alterations typical of myonecrosis in 14.6 +/- 1.0% of EDL muscle fibers. In addition, BthTX-I blocked 50% of both directly and indirectly evoked contractions in PD preparations in 72.1 +/- 9.1 and 21.1 +/- 2.0 min, respectively. Pre-incubation with suramin abolished both the muscle-damaging and muscle-paralyzing activities of BthTX-I. Since suramin is a polyanionic substance, we suggested that its effects result from the formation of inactive acid-base complexes with BthTX-I. (C) 2003 Elsevier Ltd. All rights reserved.
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Coffee (Coffea arabica L.) plants were grown in small (3-L), medium (10-L) and large (24-L) pots for 115 or 165 d after transplanting (DAT), which allowed different degrees of root restriction. Effects of altered source : sink ratio were evaluated in order to explore possible stomatal and non-stomatal mechanisms of photosynthetic down-regulation. Increasing root restriction brought about large and general reductions in plant growth associated with a rising root : shoot ratio. Treatments did not affect leaf water potential or leaf nutrient status, with the exception of N content, which dropped significantly with increasing root restriction even though an adequate N supply was available. Photosynthesis was severely reduced when plants were grown in small pots; this was largely associated with non-stomatal factors, such as decreased Rubisco activity. At 165DAT contents of hexose, sucrose, and amino acids decreased in plants grown in smaller pots, while those of starch and hexose-P increased in plants grown in smaller pots. Photosynthetic rates were negatively correlated with the ratio of hexose to free amino acids, but not with hexose content. Activities of acid invertase, sucrose synthase, sucrose-P synthase, fructose-1,6- bisphosphatase, ADP-glucose pyrophosphorylase, starch phosphorylase, glyceraldehyde-3-P dehydrogenase, PPi : fructose-6-P 1-phosphotransferase and NADP : glyceraldehyde-3-P dehydrogenase all decreased with severe root restriction. Glycerate-3-P : Pi and glucose-6-P : fructose-6-P ratios decreased accordingly. Photosynthetic down-regulation was unlikely to have been associated directly with an end-product limitation, but rather with decreases in Rubisco. Such a down-regulation was largely a result of N deficiency caused by growing coffee plants in small pots.
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Guanethidine, a chemical that selectively blocks sympathetic noradrenergic neurons, was used to investigate the role of sympathetic innervation in the fertility of rat epididymal sperm, using both natural mating and in utero insemination protocols. This animal model correlates, at least in part, with spinal cord injury (SCI) in men. Adult male rats were treated daily by i.p. injections, for 21 or 42 days, with 0 or 6.25 mg/kg guanethidine. To compare the effects of guanethidine-induced sympathectomy with those following surgically induced sympathectomy, the inferior mesenteric ganglion and the proximal hypogastric nerves were removed in another group of rats. Both chemically and surgically induced sympathectomy increased the weight of the epididymis and seminal vesicles/coagulating glands as well as the number and the transit time of cauda epididymal sperm. Neither serum testosterone levels nor LH was affected by treatment with guanethidine. Using natural mating, no litters were produced by guanethidine-treated rats. Chemically denervated rats failed to produce copulatory plugs or ejaculate into the uterus. However, distal cauda epididymal sperm from chemically or surgically denervated rats displayed normal fertilization ability (80%) using in utero inseminations. In addition, the sperm of denervated rats did not show abnormal sperm chromatin structure using an assay that detects DNA damage. We conclude that sympathectomy delays the transit of sperm through the cauda epididymidis and produces ejaculatory dysfunction but does not compromise sperm quality in the distal cauda epididymidis. Moreover, these data provide compelling evidence that there is no association between the prolonged transit time of sperm within the epididymis, i.e., pre-ejaculatory sperm aging, and the fertility of those sperm, which has important implications for artificial insemination using sperm from men with SCI.