940 resultados para maintenance of the genome


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Two Brazilian Potato virus Y (PVY) isolates were biologically characterized as necrotic (PVY-NBR) and common (PVY-OBR) based upon symptoms on test plants. Additional characterization was performed by sequencing a cDNA corresponding to the 3' terminal region of the viral genome. The sequence consisted of 195 nucleotides (nt) coding part of the nuclear inclusion body b (NIb) gene, 804 nt of the coat protein (CP) gene, and 328 nt (PVY-OBR) or 326 nt (PVY-NBR) of the 3'-untranslated region (UTR). Translation of the sequence resulted in one single open reading frame with part of the NIb and a CP of 267 amino acids. The two isolates shared 95.1% similarity in the CP amino acid sequence. The CP and the 3'-UTR sequence of the Brazilian isolates were compared to those of other PVY isolates previously reported and unrooted phylogenetic trees were constructed. The trees revealed a separation of two distinct clusters, one comprising most of the common strains and the other comprising the necrotic strains. PVY-OBR was clustered in the common group and PVY-NBR in the necrotic one.

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Papaya ringspot virus (PRSV) is the causal agent of the main papaya (Carica papaya) disease in the world. Brazil is currently the world's main papaya grower, responsible for about 40% of the worldwide production. Resistance to PRSV on transgenic plants expressing the PRSV coat protein (cp) gene was shown to be dependent on the sequence homology between the cp transgene expressed in the plant genome and the cp gene from the incoming virus, in an isolate-specific fashion. Therefore, knowledge of the degree of homology among the cp genes from distinct PRSV isolates which are present in a given area is important to guide the development of transgenic papaya for the control of PRSV in that area. The objective of the present study was to assess the degree of homology among the PRSV cp genes of several Brazilian isolates of this virus. Papaya and PRSV are present in many different ecosystems within Brazil. Twelve PRSV isolates, collected in eight different states from four different geographic regions, were used in this study. The sequences of the cp gene from these isolates were compared among themselves and to the gene used to generate transgenic papaya for Brazil. An average degree of homology of 97.3% at the nucleotide sequence was found among the Brazilian isolates. When compared to 27 isolates from outside Brazil in a homology tree, the Brazilian isolates were clustered with Australian, Hawaiian, and Central and North American isolates, with an average degree of homology of 90.7% among them.

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Many viral diseases, including leafroll, which is of great economic importance, affect grapevines (Vitis spp.). A complex of eight viruses [Grapevine leafroll-associated virus (GLRaV) -1 to 8] is associated with this disease. The objective of this study was to compare the variability of the 3' terminal region of the polymerase gene of three isolates of GLRaV-3 (Grapevine leafroll-associated virus-3), from Submédio do Vale do Rio São Francisco (Petrolina-PE) with that of other isolates available at the GenBank, including an isolate from North America and another from Southern Brazil. The viral RNA was extracted from three infected ELISA reactive plants and a fragment of 340 bp was amplified, by RT-PCR, using primers that recognize that portion of the polymerase gene found between nucleotides 8267 and 8606. The three isolates from Vale do Rio São Francisco named Pet-1, Pet-2 and Pet-3, showed similarities ranging from 98% and 94%, respectively to the isolates from North America (AF037268) and Southern Brazilian (AF438411). Considering the whole genome, the main variation found was one amino acid change at position 2766 (F2766Y). These preliminary data indicate the existence of a natural variation among GLRaV-3 isolates from grapevines. This could be due to the vegetative propagation and long cycle of the plant, associated with the error-prone nature of RNA-dependent RNA polymerase.

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Leafroll is an economically important disease affecting grapevines (Vitis spp.). Nine serologically distinct viruses, Grapevine leafroll-associated virus-1 through 9, are associated with this disease. The present study describes the coat protein gene sequence of four GLRaV-3 isolates occurring in the São Francisco River basin, Northeastern Brazil. The viral RNA was extracted from GLRaV-3 ELISA-positive plants and the complete coat protein gene was amplified by RT-PCR. Sequences were generated automatically and compared to the complete coat protein sequence from North American (NY1) and Chinese (Dawanhong Nº2 and SL10) GLRaV-3 isolates. The four studied isolates, named Pet-1 through 4, showed deduced amino acid identities of 98-100% (Pet-1 through 3) and 95% (Pet-4) with North American and Chinese isolates. A total of seventeen amino acid substitutions was detected among the four characterized isolates in comparison to the NY1, Dawanhong No.2 and SL10 sequences. The results indicated the existence of natural variation among GLRaV-3 isolates from grapevines, also demonstrating a lack of correlation between sequence data and geographic origin. This variability should be considered when selecting regions of the viral genome targeted for reliable and consistent virus molecular detection.

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The study explores knowledge transfer between retiring employees and their successors in expert work. My aim is to ascertain whether there is knowledge development or building new knowledge related to this organisational knowledge transfer between generations; in other words, is the transfer of knowledge from experienced, retiring employees to their successors merely retention of the existing organisational knowledge by distributing it from one individual to another or does this transfer lead to building new and meaningful organisational knowledge. I call knowledge transfer between generations and the possibly related knowledge building in this study knowledge sharing between generations. The study examines the organisation and knowledge management from a knowledge-based and constructionist view. From this standpoint, I see knowledge transfer as an interactive process, and the exploration is based on how the people involved in this process understand and experience the phenomenon studied. The research method is organisational ethnography. I conducted the analysis of data using thematic analysis and the articulation method, which has not been used before in organisational knowledge studies. The primary empirical data consists of theme interviews with twelve employees involved in knowledge transfer in the organisation being studied and five follow-up theme interviews. Six of the interviewees are expert duty employees due to retire shortly, and six are their successors. All those participating in the follow-up interviews are successors of those soon to retire from their expert responsibilities. The organisation in the study is a medium-sized Finnish firm, which designs and manufactures electrical equipment and systems for the global market. The results of the study show that expert work-related knowledge transfer between generations can mean knowledge building which produces new, meaningful knowledge for the organisation. This knowledge is distributed in the organisation to all those that find it useful in increasing the efficiency and competitiveness of the whole organisation. The transfer and building of knowledge together create an act of knowledge sharing between generations where the building of knowledge presupposes transfer. Knowledge sharing proceeds between the expert and the novice through eight phases. During the phases of knowledge transfer the expert guides the novice to absorb the knowledge to be transferred. With the expert’s help the novice gradually comes to understand the knowledge and in the end he or she is capable of using it in his or her work. During the phases of knowledge building the expert helps the novice to further develop the knowledge being transferred so that it becomes new, useful knowledge for the organisation. After that the novice takes the built knowledge to use in his or her work. Based on the results of the study, knowledge sharing between generations takes place in interaction and ends when knowledge is taken to use. The results I obtained in the interviews by the articulation method show that knowledge sharing between generations is shaped by the novices’ conceptions of their own work goals, knowledge needs and duties. These are not only based on the official definition of the work, but also how the novices find their work or how they prioritise the given objectives and responsibilities. The study shows that the novices see their work primarily as maintenance or development. Those primarily involved in maintenance duties do not necessarily need knowledge defined as transferred between generations. Therefore, they do not necessarily transfer knowledge with their assigned experts, even though this can happen in favourable circumstances. They do not build knowledge because their view of their work goals and duties does not require the building of new knowledge. Those primarily involved in development duties, however, do need knowledge available from their assigned experts. Therefore, regardless of circumstances they transfer knowledge with their assigned experts and also build knowledge because their work goals and duties create a basis for building new knowledge. The literature on knowledge transfer between generations has focused on describing either the knowledge being transferred or the means by which it is transferred. Based on the results of this study, however, knowledge sharing between generations, that is, transfer and building is determined by how the novice considers his or her own knowledge needs and work practices. This is why studies on knowledge sharing between generations and its implementation should be based not only on the knowledge content and how it is shared, but also on the context of the work in which the novice interprets and shares knowledge. The existing literature has not considered the possibility that knowledge transfer between generations may mean building knowledge. The results of this study, however, show that this is possible. In knowledge building, the expert’s existing organisational knowledge is combined with the new knowledge that the novice brings to the organisation. In their interaction this combination of the expert’s “old” and the novice’s “new” knowledge becomes new, meaningful organisational knowledge. Previous studies show that knowledge development between the members of an organisation is the prerequisite for organisational renewal which in turn is essential for improved competitiveness. Against this background, knowledge building enables organisational renewal and thus enhances competitiveness. Hence, when knowledge transfer between generations is followed by knowledge building, the organisation kills two birds with one stone. In knowledge transfer the organisation retains the existing knowledge and thus maintains its competitiveness. In knowledge building the organisation developsnew knowledge and thus improves its competitiveness.

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The nucleus is a membrane enclosed organelle containing most of the genetic information of the cell in the form of chromatin. The nucleus, which can be divided into many sub-organelles such as the nucleoli, the Cajal bodies and the nuclear lamina, is the site for several essential cellular functions such as the DNA replication and its regulation and most of the RNA synthesis and processing. The nucleus is often affected in disease: the size and the shape of the nucleus, the chromatin distribution and the size of the nucleoli have remained the basis for the grading of several cancers. The maintenance of the vertebrate body shape depends on the skeleton. Similarly, in a smaller context, the shape of the cell and the nucleus are mainly regulated by the cytoskeletal and nucleoskeletal elements. The nuclear matrix, which by definition is a detergent, DNase and salt resistant proteinaceous nuclear structure, has been suggested to form the nucleoskeleton responsible for the nuclear integrity. Nuclear mitotic apparatus protein, NuMA, a component of the nuclear matrix, is better known for its mitotic spindle organizing function. NuMA is one of the nuclear matrix proteins suggested to participate in the maintenance of the nuclear integrity during interphase but its interphase function has not been solved to date. This thesis study concentrated on the role of NuMA and the nuclear matrix as structural and functional components of the interphase nucleus. The first two studies clarified the essential role of caspase-3 in the disintegration of the nuclear structures during apoptosis. The second study also showed NuMA and chromatin to co-elute from cells in significant amounts and the apoptotic cleavage of NuMA was clarified to have an important role in the dissociation of NuMA from the chromatin. The third study concentrated on the interphase function of NuMA showing NuMA depletion to result in cell cycle arrest and the cytoplasmic relocalization of NuMA interaction partner GAS41. We suggest that the relocalization of the transcription factor GAS41 may mediate the cell cycle arrest. Thus, this study has given new aspects in the interactions of NuMA, chromatin and the nuclear matrix.

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The Theorica Pantegni is a medieval medical textbook written in Latin. The author was Constantine the African (Constantinus Africanus), a monk of Tunisian origin. He compiled the work in the latter half of the eleventh century at the Benedictine monastery of Monte Cassino in Italy. - Manuscript Eö.II.14, containing the Theorica Pantegni published here, belongs today to the National Library of Finland. It can be dated to the third quarter of the twelfth century, which makes it one of the earliest surviving exemplars of the Theorica Pantegni: over seventy manuscripts of the work survive, of which about fifteen can be dated to the twelfth century. Manuscript Eö.II.14 is written in black ink on 210 parchment leaves (recto and verso), amounting to 420 pages, in pre-Gothic script. - The present text is a transcription of Ms Eö.II.14. The goal is to provide the reader with an accessible text that is faithful to the original.

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The "Serra do Mar" region comprises the largest remnant of the Brazilian Atlantic Forest. The coast of the Paraná State is part of the core area of the "Serra do Mar" corridor and where actions for biodiversity conservation must be planned. In this study we aimed at characterizing the landscape structure in the APA-Guaraqueçaba, the largest protected area in this region, in order to assist environmental policies of this region. Based on a supervised classification of a mosaic of LANDSAT-5-TM satellite images (from March 2009), we developed a map (1:75,000 scale) with seven classes of land use and land cover and analyzed the relative quantities of forests and modified areas in slopes and lowlands. The APA-Guaraqueçaba is comprised mainly by the Dense Ombrophilous Forest (68.6% of total area) and secondary forests (9.1%), indicating a forested landscape matrix; anthropogenic and bare soil areas (0.8%) and the Pasture/Grasslands class (4.2%) were less representative. Slopes were less fragmented and more preserved (96.3% of Dense Ombrophilous Forest and secondary forest) than lowlands (71.3%), suggesting that restoration initiatives in the lowlands must be stimulated in this region. We concluded that most of the region sustains well-conserved ecosystems, highlighting the importance of Paraná northern coast for the biodiversity maintenance of the Atlantic Forest.

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The existence of a minimum storage capacity of grains as a condition for the maintenance of regulator physical stocks has been used as a strategic factor in the agribusiness expansion. However, in Brazil the storage infrastructure has not followed the growth of the agricultural sector. This fact is evident in the case of soybeans that currently represent 49% of grain production in the country, whose volume production has been increasing significantly over the years. This study aimed to predict the futureneeds of static storage capacity of soybeans from historical data to estimate the investment needed to install storage units in Brazil for the next five years. A statistic analysis of collected data allowed a forecast and identification of the number of storage units that should be installed to meet the storage needs of soybeans in the next five years. It was concluded that by 2015 the soybean storage capacity should be 87 million tons, and to store 49% of soybeans produced, 1,104 storage units should be installed at a cost of R$ 442 million.

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Scarcity of long-term series of sediment-related variables has led watershed managers to apply mathematical models to simulate sediment fluxes. Due to the high efforts for installation and maintenance of sedimentological gauges, tracers have been pointed out as an alternative to validate soil redistribution modelling. In this study, the 137Cs technique was used to assess the WASA-SED model performance at the Benguê watershed (933 km²), in the Brazilian semiarid. Qualitatively, good agreement was found among the 137Cs technique and the WASA-SED model results. Nonetheless, quantitatively great differences, up to two orders of magnitude, were found between the two methods. Among the uncertainties inherent to the 137Cs technique, definition of the reference inventory seems to be a major source of imprecision. In addition, estimations of water and sediment fluxes with mathematical models usually also present high uncertainty, contributing to the quantitative differences of the soil redistribution estimates with the two methods.

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PURPOSE: To investigate the association between polymorphisms in genes that encode enzymes involved in folate- and vitamin B12-dependent homocysteine metabolism and recurrent spontaneous abortion (RSA).METHODS: We investigated the C677T and A1298C polymorphisms of the methylenetetrahydrofalate reductase gene (MTHFR), the A2756G polymorphism of the methionine synthase gene (MS) and the 844ins68 insertion of the cystathionine beta synthetase gene (CBS). The PCR technique followed by RFLP was used to assess the polymorphisms; the serum levels of homocysteine, vitamin B12 and folate were investigated by chemiluminescence. The EPI Info Software version 6.04 was used for statistical analysis. Parametric variables were compared by Student's t-test and nonparametric variables by the Wilcoxon rank sum test.RESULTS: The frequencies of gene polymorphisms in 89 women with a history of idiopathic recurrent miscarriage and 150 controls were 19.1 and 19.6% for the C677T, insertion, 20.8 and 26% for the A1298C insertion, 14.2 and 21.9% for the A2756G insertion, and 16.4 and 18% for the 844ins68 insertion, respectively. There were no significant differences between case and control groups in any of the gene polymorphisms investigated. However, the frequency of the 844ins68 insertion in the CBS gene was higher among women with a history of loss during the third trimester of pregnancy (p=0.003). Serum homocysteine, vitamin B12 and folate levels id not differ between the polymorphisms studied in the case and control groups. However, linear regression analysis showed a dependence of serum folate levels on the maintenance of tHcy levels.CONCLUSION: The investigated gene polymorphisms and serum homocysteine, vitamin B12 and folate levels were not associated with idiopathic recurrent miscarriage in the present study. Further investigations are needed in order to confirm the role of the CBS 844ins68 insertion in recurrent miscarriage.

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Bovine papillomavirus type 8 (BPV-8) was first detected and described in teat warts as well as in healthy teat skin from cattle raised in Japan. The entire viral genome was sequenced in 2007. Additionally, a variant of BPV-8, BPV-8-EB, was also identified from papillomatous lesions of a European bison in Slovakia. In Brazil, despite the relatively common occurrence of BPV infections, the identification and determination of viral types present in cattle is still sporadic. The aim of this study is to report the occurrence of the recently described BPV-8 in Brazil. The virus was identified in a skin warts obtained from a beef cattle herd located in Parana state, southern Brazil. The papilloma had a macular, non-verrucous gross aspect and was located on the dorsal thorax of a cow. Polymerase chain reaction (PCR) was performed using generic primers for partial amplification of L1 gene. The obtained amplicon (480bp) was cloned and two selected clones were sequenced. The nucleotide sequence was compared to existing papillomaviral genomic sequences, identifying the virus as BPV type 8. This study represents the first report of BPV-8 occurrence in Brazil, what suggests its presence among Brazilian cattle.

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Abstract: Currently the importance of using alternative strategies for biodiversity conservation is emphasized and since the establishment of germplasm bank is an alternative to the conservation of endangered species. This is a technique of great importance for the maintenance of Brazilian fauna. Since the early70'sthere was a growing concern about the need to preserve essential genetic resources for food and agriculture, mainly for conservation of genetic material from farm animals. Thus was created the Brasilia Zoo, in July 2010, the first Germplasm Bank of Wild Animals in Latin America, as an alternative strategy for the conservation of threatened or endangered species, using both gametes and somatic cells and stem cells. Then we argue to create new banks or research networks among different regions with aimed to tissue preservation.

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Biological systems are complex dynamical systems whose relationships with environment have strong implications on their regulation and survival. From the interactions between plant and environment can emerge a quite complex network of plant responses rarely observed through classical analytical approaches. The objective of this current study was to test the hypothesis that photosynthetic responses of different tree species to increasing irradiance are related to changes in network connectances of gas exchange and photochemical apparatus, and alterations in plant autonomy in relation to the environment. The heat dissipative capacity through daily changes in leaf temperature was also evaluated. It indicated that the early successional species (Citharexylum myrianthum Cham. and Rhamnidium elaeocarpum Reiss.) were more efficient as dissipative structures than the late successional one (Cariniana legalis (Mart.) Kuntze), suggesting that the parameter deltaT (T ºCair - T ºCleaf) could be a simple tool in order to help the classification of successional classes of tropical trees. Our results indicated a pattern of network responses and autonomy changes under high irradiance. Considering the maintenance of daily CO2 assimilation, the tolerant species (C. myrianthum and R. elaeocarpum) to high irradiance trended to maintain stable the level of gas exchange network connectance and to increase the autonomy in relation to the environment. On the other hand, the late successional species (C. legalis) trended to lose autonomy, decreasing the network connectance of gas exchange. All species showed lower autonomy and higher network connectance of the photochemical apparatus under high irradiance.

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The participation of the kallikrein-kinin system, comprising the serine proteases kallikreins, the protein substrates kininogens and the effective peptides kinins, in some pathological processes like hypertension and cardiovascular diseases is still a matter of controversy. The use of different experimental set-ups in concert with the development of potent and specific inhibitors and antagonists for the system has highlighted its importance but the results still lack conclusivity. Over the last few years, transgenic and gene-targeting technologies associated with molecular biology tools have provided specific information about the elusive role of the kallikrein-kinin system in the control of blood pressure and electrolyte homeostasis. cDNA and genomic sequences for kinin receptors B2 and B1 from different species were isolated and shown to encode G-protein-coupled receptors and the structure and pharmacology of the receptors were characterized. Transgenic animals expressing an overactive kallikrein-kinin system were established to study the cardiovascular effects of these alterations and the results of these investigations further corroborate the importance of this system in the maintenance of normal blood pressure. Knockout animals for B2 and B1 receptors are available and their analysis also points to the role of these receptors in cardiovascular regulation and inflammatory processes. In this paper the most recent and relevant genetic animal models developed for the study of the kallikrein-kinin system are reviewed, and the advances they brought to the understanding of the biological role of this system are discussed.