81 resultados para Employer organization


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To address understanding the organization of the 5S rRNA multigene family in the fish genome, the nucleotide sequence and organization array of 5S rDNA were investigated in the genus Leporinus, a representative freshwater fish group of South American fauna. PCR, subgenomic library screening, genomic blotting, fluorescence in situ hybridization, and DNA sequencing were employed in this study. Two arrays of 5S rDNA were identified for all species investigated, one consisting of monomeric repeat units of around 200 bp and another one with monomers of 900 bp. These 5S rDNA arrays were characterized by distinct NTS sequences (designated NTS-I and NTS-II for the 200- and 900-bp monomers, respectively); however, their coding sequences were nearly identical. The 5S rRNA genes were clustered in two chromosome loci, a major one corresponding to the NTS-I sites and a minor one corresponding to the NTS-II sites. The NTS-I sequence was variable among Leporinus spp., whereas the NTS-II was conserved among them and even in the related genus Schizodon. The distinct 5S rDNA arrays might characterize two 5S rRNA gene subfamilies that have been evolving independently in the genome.

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The effects of massive lesions of the telencephalon on the behavioral repertoire of captive pigeons were investigated. The behavior of four birds with an intact telencephalon was compared to that of four birds submitted to ablation of telencephalic structures. Behavioral audio recording was done according to previously defined categories in three daily sessions for fifteen days. Experimental birds were followed up for one month. Immediately after the lesion, operated birds showed decreases in the occurrence of different behaviors such as coordinated movements, feeding, interaction, preening, maintenance, exploration and vocalization and increases in locomotion and discrete movements of the body when compared to the control birds (P < 0.05). Recovery of exploration (P < 0.05), feeding and localization was observed during the follow-up period. These data are interpreted as suggestive of a functional role of the telencephalon in the organization of behavior and a long-term recovery of behavior after detelencephalation.

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A case study of convective development in the Southwest Amazon region during the Wet Season Atmospheric Mesoscale Campaign (WETAMC) and Tropical Rainfall Measuring Mission (TRMM)/Large-Scale Biosphere-Atmosphere (LBA) Experiment in Amazonia is presented. The convective development during 7 February 1999 is shown to occur during a period of very weak large-scale forcing in the presence of topography and deforestation. The available data include dual Doppler radar analysis, radiosonde launches, and surface and boundary layer observations. The observational analysis is complemented with a series of model simulations using the RAMS with 2-km resolution over a 300 km 300 km area forced by a morning radiosonde profile. A comparison of the observed and simulated thermodynamic transformation of the boundary layer and of the formation of convective lines, and of their kinematic and microphysical properties is presented. It is shown that only a few very deep and intense convective cells are necessary to explain the overall precipitating line formation and that discrete propagation and coupling with upper atmosphere circulations may explain the appearance of several lines. The numerical simulation indicates that topography may be the cause of initial convective development, although later on the convective line is parallel to the midlevel shear. There are indications that small-scale deforestation may have an effect on increasing rainfall in the wet season when the large-scale forcing is very weak.

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The complete nucleotide sequence of the genomic RNA 1 (8745 nt) and RNA 2 (4986 nt) of Citrus leprosis virus cytoplasmic type (CiLV-C) was determined using cloned cDNA. RNA 1 contains two open reading frames (ORFs), which correspond to 286 and 29 kDa proteins. The 286 kDa protein is a polyprotein putatively involved in virus replication, which contains four conserved domains: methyltransferase, protease, helicase and polymerase. RNA 2 contains four ORFs corresponding to 15, 61, 32 and 24 kDa proteins, respectively. The 32 kDa protein is apparently involved in cell-to-cell movement of the virus, but none of the other putative proteins exhibit any conserved domain. The 5' regions of the two genomic RNAs contain a 'cap' structure and poly(A) tails were identified in the 3'-terminals. Sequence analyses and searches for structural and non-structural protein similarities revealed conserved domains with members of the genera Furovirus, Bromovirus, Tobravirus and Tobamovirus, although phylogenetic analyses strongly suggest that CiLV-C is a member of a distinct, novel virus genus and family, and definitely demonstrate that it does not belong to the family Rhabdoviridae, as previously proposed. Based on these results it was proposed that Citrus leprosis virus be considered as the type member of a new genus of viruses, Cilevirus.

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Objective. To investigate the proxy-reported health-related quality of life (HRQOL) and its determinants in patients with juvenile idiopathic arthritis (JIA).Methods. In this multinational, multicenter, cross-sectional study, HRQOL of patients with JIA was assessed through the Child Health Questionnaire (CHQ) and was compared with that of healthy children of similar age from the same geographic area. of joint inflammation, Childhood Health Assessment Questionnaire (CHAQ), and erythrocyte sedimentation rate.Results. A total of 6,639 participants (3,324 with JIA and 3,315 healthy) were enrolled from 32 countries. The mean SD physical and psychosocial summary scores of the CHQ were significantly lower in patients with JIA than in healthy children (physical: 44.5 +/- 10.6 versus 54.6 +/- 4.0, P < 0.0001; psychosocial: 47.6 +/- 8.7 versus 51.9 +/- 7.59 P < 0.0001), with the physical well-being domain being most impaired. Patients with persistent oligoarthritis had better HRQOL compared with other subtypes, whereas HRQOL was similar across patients with systemic arthritis, polyarthritis, and extended oligoarthritis. A CHAQ score > 1 and a pain intensity rating > 3.4 cm on a 10-cm visual analog scale were the strongest determinants of poorer HRQOL in the physical and psychosocial domains, respectively.Conclusion. We found that patients with JIA have a significant impairment of their HRQOL compared with healthy peers, particularly in the physical domain. Physical well-being was mostly affected by the level of functional impairment, whereas the intensity of pain had the greatest influence on psychosocial health.

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The present study was carried out under field conditions in Rio Claro, Southeastern Brazil. The following average life-spans of adults of Mischocyttarus cerberus styx were observed: queens 191.1 days, workers 14.0 days, and males 10.7 days. The short longevity of workers is attributed to the early foraging activity which was performed since the first week of adult age. The life table of the workers revealed high mortality rates during the first three weeks of life. Twenty-four behavioral categories were reported for these wasps and a comparative behavioral catalogue showed that the solitary foundresses (pre-emergence stage) are significantly more active than the queens (post-emergence stage) because they have to perform all the tasks for the nest maintenance. On the other hand, the queens were highly active even in the presence of the workers. The small number of individuals on the nest was the probable cause of the high activity of the queens in the post-emergence colonies. There was no clear division of tasks among workers according to their age (in weeks), so that most of the behavior categories were potentially performed by any worker of any age. Dead queens were replaced by their daughters.

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The nucleolar material of Chariesterus armatus was analyzed during spermiogenesis in cell preparations impregnated with silver nitrate. Nucleolar corpuscles were observed in spermatids at the beginning of the process, showing that this organoid is also maintained after meiosis. In addition, nucleoli were seen in the round spermatids connected to the X-chromosome (bearer of the nucleolar organizer in C. armatus), indicating de novo synthesis of nucleolar material. This differs from the reorganization of ribosomal granules, transported from meiotic spermatocytes to round spermatids, where they would support protein synthesis, which is reported for other species. We also observed connections of nucleolar corpuscles to the nuclear membrane regions where the tail and the acrosome will be formed, suggesting close involvement of the nucleolar material in the formation of these structures. In addition to the nucleolar bodies, we detected silver-positive structures, which will require new approaches to clarify their role. One of these structures, observed in the cytoplasm, appears to correspond to the chromatoid body, which has been found in several organisms, but is still poorly understood; another is a complex structure to which the tail appears to be connected. We conclude that C. armatus is an appropriate model for understanding not only the synthesis of rRNA in the spermiogenesis, but also the functional meaning of the close relationship of nucleolar material with other structures during this process.

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Chromosome mapping and studies of the genomic organization of repetitive DNA sequences provide valuable insights that enhance our evolutionary and structural understanding of these sequences, as well as identifying chromosomal rearrangements and sex determination. This study investigated the occurrence and organization of repetitive DNA sequences in Leporinus elongatus using restriction enzyme digestion and the mapping of sequences by chromosomal fluorescence in situ hybridization (FISH). A 378-bp fragment with a 54.2% GC content was isolated after digestion with the SmaI restriction enzyme. BLASTN search found no similarity with previously described sequences, so this repetitive sequence was named LeSmaI. FISH experiments were conducted using L. elongatus and other Anostomidae species, i.e. L. macrocephalus,L. obtusidens, L. striatus, L. lacustris, L. friderici, Schizodon borellii, S. isognathus, and Abramites hypselonotus which detected signals that were unique to male and female L. elongatus individuals. Double-FISH using LeSmaI and 18S rDNA showed that LeSmaI was located in a nucleolus organizer region (NOR) in the male and female metaphases of L. elongatus. This report also discusses the role of repetitive DNA associated with NORs in the diversification of Anostomidae species karyotypes. Copyright © 2012 S. Karger AG, Basel.

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Cichlids are important in the aquaculture and ornamental fish trade and are considered models for evolutionary biology. However, most studies of cichlids have investigated African species, and the South American cichlids remain poorly characterized. Studies in neotropical regions have focused almost exclusively on classical cytogenetic approaches without investigating physical chromosomal mapping of specific sequences. The aim of the present study is to investigate the genomic organization of species belonging to different tribes of the subfamily Cichlinae (Cichla monoculus, Astronotus ocellatus, Geophagus proximus, Acaronia nassa, Bujurquina peregrinabunda, Hoplarchus psittacus, Hypselecara coryphaenoides, Hypselecara temporalis, Caquetaia spectabilis, Uaru amphiacanthoides, Pterophyllum leopoldi, Pterophyllum scalare, and Symphysodon discus) and reexamine the karyotypic evolutionary patterns proposed for this group. Variations in some cytogenetic markers were observed, although no trends were found in terms of the increase, decrease, or maintenance of the basal diploid chromosome number 2n = 48 in the tribes. Several species were observed to have 18S rDNA genetic duplications, as well as multiple rDNA loci. In most of the taxa analyzed, the 5S rDNA was located in the interstitial region of a pair of homologous chromosomes, although variations from this pattern were observed. Interstitial telomere sites were also observed and appear to be involved in chromosomal rearrangement events and the accumulation of repeat-rich satellite DNA sequences. Our data demonstrated the karyotypic diversity that exists among neotropical cichlids, suggesting that most of this diversity is due to the repetitive sequences present in heterochromatic regions and that repeat sequences have greatly influenced the karyotypic evolution of these fishes. © 2012 Springer Science+Business Media B.V.

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Repetitive DNA sequences constitute a great portion of the genome of eukaryotes and are considered key components to comprehend evolutionary mechanisms and karyotypic differentiation. Aiming to contribute to the knowledge of chromosome structure and organization of some repetitive DNA classes in the fish genome, chromosomes of two allopatric populations of Astyanax bockmanni were analyzed using classic cytogenetics techniques and fluorescent in situ hybridization, with probes for ribosomal DNA sequences, histone DNA and transposable elements. These Astyanax populations showed the same diploid number (2n = 50), however with differences in chromosome morphology, distribution of constitutive heterochromatin, and location of 18S rDNA and retroelement Rex3 sites. In contrast, sites for 5S rDNA and H1, H3 and H4 histones showed to be co-located and highly conserved. Our results indicate that dispersion and variability of 18S rDNA and heterochromatin sites are not associated with macro rearrangements in the chromosome structure of these populations. Similarly, distinct evolutionary mechanisms would act upon histone genes and 5S rDNA, contributing to chromosomal association and co-location of these sequences. Data obtained indicate that distinct mechanisms drive the spreading of repetitive DNAs in the genome of A. bockmanni. Also, mobile elements may account for the polymorphism of the major rDNA sites and heterochromatin in this genus. © 2013 Springer Science+Business Media Dordrecht.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)