988 resultados para condensation symbol


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Considering the performance of CAM epiphytes under high levels of radiation or in shaded environments, with growth rate proportional to light intensity, the objective of this work was to evaluate the effects of long-term light stress on the growth of a Brazilian epiphytic orchid, Cattleya forbesii Lindl. X Laelia tenebrosa Rolfe. Two groups of plants were used in the first experiment, one under 90% (Symbol>@ 1,650 µmol.m-2.s-1) of Photosynthetically Active Radiation (PAR) and the other maintained under 22.5% (Symbol>@ 400 µmol.m-2.s-1). In the second experiment the diffusive resistance, transpiration rate and fluorescence levels were monitored for plants that were under 22.5% of PAR, under 90% and plants transferred from 22.5 to 90%. Our results show that light intensity interfered with growth and development of this orchid. Data on the changes in pseudobulb volume throughout the time course of growth suggest that water and reserves stored in the back shoots are translocated to the current shoot. Regarding stomatal resistance, plants under 22.5% of PAR reached a largest stomatal aperture during the night, whereas those under 90% only after dawn. After transfer from 22.5% PAR to 90% PAR the ratio of Fv/Fm decreased from approximately 0.8 to 0.7. This suggests the limitation of photoprotection mechanisms in the leaf and the results observed after the transfer of plants from 22.5% to 90% reinforce the possibility that a photoinhibition is reflected in a decrease in growth rate.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Tässä väitöskirjassa tarkastellaan suomalaisen puoluejohtajuuden ja suuren puolueen johtajaksi nousun murroskautta 1980-luvun lopulta 2010-luvulle median ja politiikan vuorovaikutuksen näkökulmasta. Puolueiden johtaminen on myös Suomessa ollut miesten työtä, ja perinteisesti tehtävään on ollut yksi väylä: asettuminen ehdolle puheenjohtajavaalissa ja valituksi tulo puoluekokouksessa. Tarkastelujakson alkupuolella naisia oli Suomessa ensimmäistä kertaa ehdolla suurten puolueiden puheenjohtajavaaleissa. Kauden loppupuolella heitä myös valittiin tuohon tehtävään ja ensimmäiset naiset nousivat pääministeriksi. Tämä historiallinen murros päätti liki satavuotisen perinteen, jossa miehet ovat olleet Suomessa sekä suurten puolueiden että hallitustyön johtajia. Julkisessa keskustelussa kysymys tasa-arvosta jäi toissijaiseksi: naisia alettiin valita puoluejohtajiksi tilanteissa, joissa heidän valintansa nähtiin puolueille edulliseksi. Naisen valinta tulkittiin miehen valintaa merkittävämmäksi symboliseksi viestiksi, johon liitettiin ajatuksia uudistumisesta ja puolueen julkisuuskuvan parantamisesta. Merkille pantavaa on, että naisten ensimmäiset valinnat suurten puolueiden johtajiksi tapahtuivat vaiheessa, jossa puoluejohtajien valta-asema on vahvin kautta suomalaisen poliittisen historian. Tässä valossa näyttää siltä, että valta ei aina pakenekaan naisilta. Vaikka suomalainen yhteiskunta ja suomalaiset naiset ovat monessa mielessä olleet edelläkävijöitä tasa-arvon suhteen, politiikan johtopaikkoja tavoitelleet naiset ovat meilläkin kohdanneet kansainvälisessä tutkimuksessa naisten haasteeksi osoitettuja lasikattoja, pyöröovia ja liukkaita jyrkänteitä. Tutkittavan ajanjakson aikana konkretisoitui myös toinen mahdollinen, joskin poikkeuksellinen reitti suuren puolueen johtajaksi: pienen puolueen nouseminen suurten joukkoon eduskuntavaaleissa. Tämä vaihtoehto toteutui vuonna 2011 perussuomalaisten eduskuntavaalivoiton myötä. Perussuomalaisten nousu eduskunnan pienimmästä puolueesta kolmanneksi suurimmaksi mursi perinteisen kolmen suuren puolueen asetelman. Puolueen menestyksen seuraukset ovat olleet kauaskantoisemmat kuin ehkä ensin ajateltiin: perussuomalaisten vaalivoiton sosiaalidemokraateille, keskustalle, ja kokoomukselle aiheuttama järkytys heijastui myöhemmin myös niiden johtajavaihdoksiin ja -valintoihin. Sekä naisten läpimurrossa että populismin voittokulussa median rooli oli monisyisempi kuin siihen perinteisesti liitetty tiedon välittäjän ja valtaa pitävien toimia kriittisesti seuraavan neljännen valtiomahdin tehtävänkuva. Tutkittavalla jaksolla tiedotusvälineet tekivät onnistuneen intervention politiikan osapuoleksi. Toimittajat ottivat kantaa valintoihin ja ohjeistivat puolueita, ja puolueet taas mukauttivat näkyvyyden maksimoidakseen käytäntöjään median tarpeisiin. 1980-luvun lopulta 2010-luvulle ulottuvalla jaksolla suuren puolueen puoluejohtajaksi valikoitumisen kriteerit muuttuivat, samalla kun median merkitys johtajavalinnoissa ja myös puoluejohtajan käytännön työssä kasvoi. Mediasta tuli aiempaa konkreettisemmin johtajavalintojen ja valtakamppailun areena, ja siihen liittyvät näkökohdat nousivat myös keskeisiksi johtajan taitoja arvioitaessa. Kuka ehdokkaista toisi näkyvyyttä, ”pärjäisi” median paineissa ja vakuuttaisi äänestäjät? Vielä 1980- ja 1990-lukujen taitteessa johtajavalinnat olivat pitkälti puolueorganisaatioiden hallinnoimia prosesseja, joista lehdistö raportoi askeleen jäljessä kulkien. Viimeistään 2000-luvun ensimmäisellä vuosikymmenellä puolueet omaksuivat ajatuksen median hyödyllisyydestä. Tämän strategisen muutoksen myötä puolueet tulivat samalla luovuttaneeksi määriteltyvaltaa oman organisaationsa ulkopuolelle. Kokoomuksen vuoden 2014 johtajavaalissa silmiinpistävää oli pyrkimys sekä hyötyä julkisuudesta että palauttaa valtaa takaisin puolueelle. Politiikan mediajulkisuuden alttius tarttua myyviin poliitikkopersooniin, ilmiöihin, ristiriitoihin ja draamaan sekä vastaavasti populistijohtaja Timo Soinin ja perussuomalaisten kyky tarjota kaikkia näitä auttoivat puolueen suurvoittoon vuoden 2011 eduskuntavaaleissa. Organisaatioltaan pieni ja johtajaansa henkilöityvä puolue sai selvästi poliittista painoarvoaan suuremman julkisuuden, koska kiinnostavuus määritti näkyvyyden ja puolueen nousevasta kannatuksesta tuli yksi vaalien pääaiheista. Median ja politiikan suhteessa tapahtuneet muutokset olivat vauhdittamassa niin naisten nousua suurten puolueiden johtajiksi kuin populistisen johtajuuden läpimurtoa ja perussuomalaisten menestystä. Koska suurten puolueiden johtajista valikoituvat myös pääministerit, näiden muutosten vaikutus ulottuu Suomen poliittisesti vaikutusvaltaisimpaan tehtävään asti.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

As the national language of the PRC, the world's growing economic power and the sovereign of Hong Kong, Putonghua is a language with multiple facets of relevance for the current Special Administrative Region. This paper seeks to explore and explain different representations of Putonghua in Hong Kong's leading English-language newspaper South China Morning Post in articles published between January 2012 and February 2013. The representations are studied in the context of the different discourses in which they appear, some of which feature language(s) as a central theme and some more marginally. An overview is first presented of the scholarly research on the most important developments in Hong Kong's complex language scene from the beginnings of the colony until present day, with the aim of detecting developments and attitudes with potential relevance or parallels to the context of Putonghua today. The paper then reflects on the media and its role in producing and perpetuating discourses in the society, before turning to more practical considerations on Hong Kong's English and Chinese language media and the role of South China Morning Post in it. The methods used in analysing the discourses are those of discourse analysis, with textual analysis as its starting point, in which close attention is paid to linguistic forms as the concrete representations of meanings in a text. Particularly the immediate contexts of the appearances of the word “Putonghua” in the articles were studied carefully to detect vocabulary, grammar and semantical choices as signs of different discourses, potentially also revealing fundamental underlying assumptions and other “hidden meanings” in the text. Some of the most distinctive discourses in which different representations of Putonghua appeared were the Instrumental value for the individual (in which Putonghua was represented as a form of social capital); Othering of the mainlanders (in which Putonghua served as a concrete marker of distinction); Belonging to China (Putonghua as a symbol of unity); and Cultural distinctiveness of Hong Kong (Putonghua as a threat to Hong Kong's history and culture, as embodied in Cantonese). Some of these discourses were more prominent than others, and for example the discourse of Belonging to China was relatively rarely enacted in Hongkongers' voices. In general, the findings were not surprising in the light of the history, but showed a fair degree of consistency with what has been written earlier about the languages and attitudes towards them in Hong Kong. It has often been noted that Putonghua and its relation with Cantonese is a matter linked with the social identity of the colony and its citizens. While it appeared that there were no strict taboos in the representations of Putonghua in the societal context, the possibility of self-censorship cannot be ruled out as a factor toning down political discourses in the representations.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The objectives of this paper were to derive the genetic variance of inbreeding depression ( ) and to predict the range of inbreeding depression (RID) in cross-pollinated populations. The variance of inbreeding depression is a function of the genetic variances related to dominance effects (, D2, and ), and of the inbreeding coefficients of the two generations in which inbreeding depression is measured (Ft and Fg). The results showed that the higher the level of dominance of a trait, the higher the variance of inbreeding depression. The magnitudes of were expected to be lower in improved (mean gene frequencies = > 0.6) and in unimproved ( < 0.4) populations, than in composite populations ( » 0.5). Data from a maize population used to illustrate the study showed that the range of inbreeding depression in the S¥ generation of selfing was from 48.7% to 85.3% for grain yield, and from 13.9% to 24.5% for plant height. A mating design outlined to estimate the genetic variance of inbreeding depression, the range of inbreeding depression, and of the range of inbred lines is presented.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The mitotic chromosomes of 51 citrus accessions from the Centro Nacional de Pesquisa em Mandioca e Fruticultura Tropical, Cruz das Almas, BA, Brazil, were analyzed. The sample included representatives of 20 Citrus species, one of Poncirus and seven hybrids. All accessions showed 2n = 18 without any evidence of numerical variation. The most clearly variable karyotype feature was the number and position of secondary constrictions (SECs). In 19 accessions the SECs were not identified, mainly due to the degree of chromatin condensation. In the remainder they varied in number from one to three per karyotype. They were found in the proximal region of one of the three largest chromosome pairs, in the terminal/subterminal region of a smaller chromosome or, more seldom, terminally in a larger chromosome. Only in a few cases were such constrictions observed simultaneously in both homologues of the same chromosome pair. The high variability of this karyotype feature may be due to the activation of this region in the previous interphase but may also indicate a high structural variability and heterozygosity of citrus germplasms

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The a-globin major genes from diploid and tetraploid Odontophrynus americanus were studied using PCR-based technology. The cloned and sequenced amplified fragments were shown to contain most of the exon II sequences as well as the whole exon III sequence of the a-globin gene. Unexpectedly, intron 2 was entirely absent in the amplified fragments of both 2n and 4n origin. High conservation was observed among the obtained sequences when compared to corresponding sequences from human and Xenopus laevis origin. The possibility that these sequences might be pseudogenes is raised

Relevância:

10.00% 10.00%

Publicador:

Resumo:

It is well known that virtually every tissue of the amphibian larvae is highly sensitive to the mutually antagonistic actions of thyroid hormone (TH) and prolactin (PRL), but it is not known if adult amphibian tissues respond similarly to these two hormones. We have previously shown that very low doses of triiodothyronine (T3) rapidly and strongly potentiate the activation of silent vitellogenin (Vit) genes by estrogen (E2) and the autoinduction of estrogen receptor (ER) transcripts in primary cultures of adult Xenopus hepatocytes. This response to T3 is accompanied by the upregulation of thyroid hormone receptor b (TRb) mRNA. Using Northern blot and RNase protection assays, we now show that ovine PRL added for 12 h along with 2 x 10-9 M T3 will completely prevent potentiation of E2 induction of Vit mRNA in primary cultures of adult Xenopus hepatocytes. PRL also abolished the auto-upregulation of TRb mRNA and the cross-activation of autoinduction of ER mRNA. Thus, we show for the first time that the anti-TH action of PRL that is manifested in Xenopus tadpole tissues during metamorphosis is retained in adult liver, and suggest that the mutually antagonistic actions of the two hormones may be brought about by similar molecular mechanisms in larval and adult amphibian tissues

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Five bovine milk protein polymorphisms were studied in Zebuine cattle raised in Brazil, through horizontal electrophoresis on starch gel containing urea and 2-mercaptoethanol, using basic and acidic buffer systems. Allelic frequencies for a-La, b-Lg, aS1-Cn, b-Cn and k-Cn loci were estimated in six Gyr herds (N = 283), six Guzerat herds (N = 205), one Nelore herd (N = 17) and one Sindi herd (N = 22), all from São Paulo or Minas Gerais State, Brazil. Genotypic frequencies observed for each locus and breed studied are in accordance with the assumption of genetic equilibrium, demonstrating absence of high inbreeding levels for the breeds tested. The FST value found indicated significant genetic differentiation among breeds; however, the Gyr and Guzerat herds showed significantly different gene frequencies. Genetic distance estimates among zebuine breeds studied and the Holstein breed, taken as a reference for a taurine breed, showed strong differences between these two racial groups

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The binding capacity of concanavalin A (Con A) to condensed euchromatin and heterochromatin was investigated in chicken erythrocyte nuclei (CEN), mouse liver cells, Zea mays mays meristematic cells and Drosophila melanogaster polytene chromosomes after 4 N HCl hydrolysis to determine whether binding was preferentially occurring in bands and heterochromatin. Dry mass (DM) variation was investigated in CEN by interference microscopy. Feulgen and Con A reactions were employed for all materials to correlate the loci of the two reactions. Quantifications and topological verifications were carried out by video image analysis (high performance cytometry). It was observed that 4 N HCl hydrolysis caused an important DM loss in CEN leaving a level corresponding to the average DNA DM content. In this material, Con A binding was restricted to the nuclear envelope, which reinforces the idea of the absence of a nuclear matrix in these cells. The other cell types exhibited a correspondence of Feulgen-positive and Con A-reactive areas. The Con A reaction was highly positive in the condensed chromatin areas and heterochromatin. This fact led us to speculate that Con A-positive proteins may play a role in the chromatin condensation mechanism, endowing this structure with physico-chemical stability towards acid hydrolysis and contributing to its rheological properties.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The effect of two concentrations of caffeine (1500 mg/ml and 2500 mg/ml) on mitotic indices of Drosophila prosaltans was analyzed in larval brain cells. Although the differences detected between treated and control cells were not significant, the percentages obtained suggest a possible effect of caffeine in slowing the process of cell division

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The human immunoglobulin lambda variable locus (IGLV) is mapped at chromosome 22 band q11.1-q11.2. The 30 functional germline v-lambda genes sequenced untill now have been subgrouped into 10 families (Vl1 to Vl10). The number of Vl genes has been estimated at approximately 70. This locus is formed by three gene clusters (VA, VB and VC) that encompass the variable coding genes (V) responsible for the synthesis of lambda-type Ig light chains, and the Jl-Cl cluster with the joining segments and the constant genes. Recently the entire variable lambda gene locus was mapped by contig methodology and its one- megabase DNA totally sequenced. All the known functional V-lambda genes and pseudogenes were located. We screened a human genomic DNA cosmid library and isolated a clone with an insert of 37 kb (cosmid 8.3) encompassing four functional genes (IGLV7S1, IGLV1S1, IGLV1S2 and IGLV5a), a pseudogene (VlA) and a vestigial sequence (vg1) to study in detail the positions of the restriction sites surrounding the Vl genes. We generated a high resolution restriction map, locating 31 restriction sites in 37 kb of the VB cluster, a region rich in functional Vl genes. This mapping information opens the perspective for further RFLP studies and sequencing

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We report on the cytogenetic and DNA analysis of 55 families with the fragile X (FMR-1 locus) mutation (318 individuals and 15 chorionic villi samples). A total of 129 males were investigated, 54 mentally normal and 75 presenting mental retardation. Among the 54 normal males, 11 had the premutation, and none expressed the fragile site. The full mutation was detected in 73 retarded males, and 14 (18%) presented a premutation along with the full mutation (mosaics). All of them manifested the fragile site. The frequencies of fragile site expression correlated positively with the sizes of the expansion of the CGG repeats (D). Among 153 normal females, 85 were found to be heterozygous for the premutation and 15 had the full mutation. In the premutated females the fragile site was not observed or it occurred at frequencies that did not differ from those observed in 53 noncarriers. Cytogenetic analysis was thus ineffective for the diagnosis of premutated males or females. Among the 51 heterozygotes for the full mutation, 36 (70%) had some degree of mental impairment. As in males, a positive correlation was detected between the frequencies of fragile site manifestation and the size of the expansion. However, the cytogenetic test was less effective for the detection of fully mutated females, than in the case of males, since 14% false negative results were found among females. Segregation analysis confirmed that the risk of mental retardation in the offspring of heterozygotes increases with the length of D. The average observed frequency of mental retardation in the offspring of all heterozygotes was 30%. There was no indication of meiotic drive occurring in female carriers, since the number of individuals who inherited the mutation did not differ from the number of those inheriting the normal allele. No new mutations were detected in the 55 genealogies studied here.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Hb Köln was identified by DNA analysis in a Brazilian patient. A four-year old Brazilian female, with jaundice since birth, presented an abnormal band, between A2 and S, in hemoglobin electrophoresis on a cellulose acetate membrane, and a band with electrophoretic migration similar to Hb C on agar gel. Thermic instability and isopropanol precipitation tests were positive. Heinz bodies were observed in the patient’s peripheral blood. Sequencing of the three exons of the b globin gene detected a transition from G to A in the first position of codon 98. This alteration does not create or abolish any known restriction site. In this case, confirmation of the mutation was accomplished by allele-specific oligonucleotide hybridization, which is a simple and fast identification method when the clinical data and hematological and electrophoretic patterns are suggestive of Hb Köln.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

It has been shown for several DNA probes that the recently introduced Fast-FISH (fluorescence in situ hybridization) technique is well suited for quantitative microscopy. For highly repetitive DNA probes the hybridization (renaturation) time and the number of subsequent washing steps were reduced considerably by omitting denaturing chemical agents (e.g., formamide). The appropriate hybridization temperature and time allow a clear discrimination between major and minor binding sites by quantitative fluorescence microscopy. The well-defined physical conditions for hybridization permit automatization of the procedure, e.g., by a programmable thermal cycler. Here, we present optimized conditions for a commercially available X-specific a-satellite probe. Highly fluorescent major binding sites were obtained for 74oC hybridization temperature and 60 min hybridization time. They were clearly discriminated from some low fluorescent minor binding sites on metaphase chromosomes as well as in interphase cell nuclei. On average, a total of 3.43 ± 1.59 binding sites were measured in metaphase spreads, and 2.69 ± 1.00 in interphase nuclei. Microwave activation for denaturation and hybridization was tested to accelerate the procedure. The slides with the target material and the hybridization buffer were placed in a standard microwave oven. After denaturation for 20 s at 900 W, hybridization was performed for 4 min at 90 W. The suitability of a microwave oven for Fast-FISH was confirmed by the application to a chromosome 1-specific a-satellite probe. In this case, denaturation was performed at 630 W for 60 s and hybridization at 90 W for 5 min. In all cases, the results were analyzed quantitatively and compared to the results obtained by Fast-FISH. The major binding sites were clearly discriminated by their brightness

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A recessive mutant cell line, B7, which is partially responsive to both interferon (IFN)- a and IFN-g is described. B7 was FACS sorted from a cellular pool, which was obtained from the parental cell line 2C4, after several rounds of mutagenesis. The partial responsiveness to IFN was observed both in terms of expression of cell surface markers (CD2, class I and II HLAs) and mRNA expression of IFN-stimulated genes (9-27; 6-16; 2'-5' OAS; GBP and HLA-DRa). A genetic cross with the U4 mutant (JAK1-, a member of the Janus family of nonreceptor tyrosine kinase) did not restore full IFN-responsiveness to B7, and JAK1 cDNA transfection into B7 restored the wild phenotype of the cell line, defining B7 as a member of the U4 complementation group. Nevertheless, JAK1 mRNA was not detected in this mutant. Transcriptional regulator complexes such as IRF1/2 (IFN-regulatory factor) and ISGF3-g (IFN-stimulated gene factor) were constitutively formed in the B7 mutant and co-migrated with the IFN-induced complexes expressed in the parental cell line 2C4. Thus, this cell line seems to be useful for understanding cis-acting elements governing JAK1 mRNA expression.