Tamanho de coleção original, métodos de agrupamento e amostragem para obtenção de coleção nuclear de germoplasma

O objetivo deste trabalho foi verificar o efeito do tamanho da coleção original de germoplasma sobre eficácia de diferentes métodos de agrupamento e de amostragem, utilizados na obtenção de coleções nucleares, e comparar esses métodos no estabelecimento de coleções nucleares. Foram simulados sete tamanhos de coleções originais e utilizadas sete estratégias de amostragem para estabelecimento de coleções nucleares, com uso de caracteres morfo-agronômicos. Oito estratégias de obtenção de coleção nuclear foram empregadas, seis com técnicas de agrupamento (Tocher e Tocher sequencial) e duas sem agrupamento (aleatória e Tocher invertido). Nas estratégias de agrupamento, foram empregadas as amostragens constante, logarítmica e proporcional. Determinaram-se a variância explicada, o valor do coeficiente de determinação, o coeficiente de coincidência e o coeficiente de coincidência do desvio-padrão entre a coleção nuclear e a coleção original. As estratégias de amostragem constante e logarítmica geram coleções nucleares representativas da coleção original. O agrupamento de Tocher sequencial é mais eficaz na representação da coleção original pela coleção nuclear do que o agrupamento de Tocher. Entre as estratégias avaliadas, a amostragem pelo método de Tocher com critério de aglomeração inverso foi a mais eficiente na geração de coleções nucleares representativas das coleções originais

Coregulator Control of Androgen Receptor Action by a Novel Nuclear Receptor-Binding Motif

The androgen receptor (AR) is a ligand-activated transcription factor that is essential for prostate cancer development. It is activated by androgens through its ligand-binding domain (LBD), which consists predominantly of 11 α-helices. Upon ligand binding, the last helix is reorganized to an agonist conformation termed activator function-2 (AF-2) for coactivator binding. Several coactivators bind to the AF-2 pocket through conserved LXXLL or FXXLF sequences to enhance the activity of the receptor. Recently, a small compound-binding surface adjacent to AF-2 has been identified as an allosteric modulator of the AF-2 activity and is termed binding function-3 (BF-3). However, the role of BF-3 in vivo is currently unknown, and little is understood about what proteins can bind to it. Here we demonstrate that a duplicated GARRPR motif at the N terminus of the cochaperone Bag-1L functions through the BF-3 pocket. These findings are supported by the fact that a selective BF-3 inhibitor or mutations within the BF-3 pocket abolish the interaction between the GARRPR motif(s) and the BF-3. Conversely, amino acid exchanges in the two GARRPR motifs of Bag-1L can impair the interaction between Bag-1L and AR without altering the ability of Bag-1L to bind to chromatin. Furthermore, the mutant Bag-1L increases androgen-dependent activation of a subset of AR targets in a genome-wide transcriptome analysis, demonstrating a repressive function of the GARRPR/BF-3 interaction. We have therefore identified GARRPR as a novel BF-3 regulatory sequence important for fine-tuning the activity of the AR.

The Schizosaccharomyces pombe cdc14 gene is required for septum formation and can also inhibit nuclear division.

A conditional heat-sensitive mutation in the cdc14 gene of the fission yeast Schizosaccharomyces pombe results in failure to form a septum. Cells become highly elongated and multinucleate as growth and nuclear division continue in the absence of cell division. This article describes the cloning of the cdc14 gene and the identification of its product, a protein of 240 amino acids, p28cdc14. A null allele of the cdc14 gene shows that the gene is essential for septum formation and completion of the cell-division cycle. Overexpression of the gene product, p28cdc14, causes cell-cycle arrest in late G2 before mitosis. Cells leaking past the block activate p34cdc2 kinase and show condensed chromosomes, but the normal rearrangements of the microtubules and microfilaments that are associated with the transition from interphase to mitosis do not occur. Overexpression of p28cdc14 in mutants, in which the timing of mitosis is altered, suggests that these effects may be mediated upstream of the mitotic inhibitor wee1. These data are consistent with the idea that p28cdc14 may play a role in both the initiation of mitosis and septum formation and, by doing so, be part of the mechanism that coordinates these two cell-cycle events.

Determination of 241Pu in nuclear waste slurries: a comparative study using LSC and ICP-MS.

(241)Pu was determined in slurry samples from a nuclear reactor decommissioning project at the Paul Scherrer Institute (Switzerland). To validate the results, the (241)Pu activities of five samples were determined by LSC (TriCarb and Quantulus) and ICP-MS, with each instrument at a different laboratory. In lack of certified reference materials for (241)Pu, the methods were further validated using the (241)Pu information values of two reference sediments (IAEA-300 and IAEA-384). Excellent agreement with the results was found between LSC and ICP-MS in the nuclear waste slurries and the reference sediments.

Adaptabilidade e estabilidade de acessos de uma coleção nuclear de arroz

O objetivo deste trabalho foi determinar o potencial produtivo e a interação entre genótipos e ambientes em 550 acessos da Coleção Nuclear de Arroz da Embrapa. O desempenho, a adaptação e a estabilidade produtiva de cada genótipo foram avaliados por meio da metodologia de análise dos efeitos principais aditivos e interações multiplicativas (AMMI), em nove experimentos de campo, realizados em seis Estados, em condição de sequeiro e irrigada, durante três anos agrícolas. Foi realizada a análise por meio de modelos lineares mistos, e as estimativas de componentes de variância foram obtidas pelo método de máxima verossimilhança residual (REML), com aplicação do procedimento de melhor predição linear não viesada (BLUP) para a predição dos valores genéticos dos efeitos aleatórios (EBLUP) associados a cada um dos acessos. O grupo de acessos com melhor desempenho foi o de linhagens e cultivares brasileiras (LCB), conforme o esperado. No entanto, foram identificadas variedades tradicionais (VT) entre os genótipos mais produtivos, o que mostra o potencial deste grupo de germoplasma em contribuir com novas fontes de variabilidade genética para programas de melhoramento. Foram identificados acessos superiores quanto à estabilidade, adaptabilidade e produtividade de grãos, entre os quais destacam-se CA880078, CA840182 e CNA00091.

Nuclear translocation and DNA recognition signals colocalized within the bZIP domain of cyclic adenosine 3',5'-monophosphate response element-binding protein CREB.

CREB is a cAMP-responsive nuclear DNA-binding protein that binds to cAMP response elements and stimulates gene transcription upon activation of the cAMP signalling pathway. The protein consists of an amino-terminal transcriptional transactivation domain and a carboxyl-terminal DNA-binding domain (bZIP domain) comprised of a basic region and a leucine zipper involved in DNA recognition and dimerization, respectively. Recently, we discovered a testis-specific transcript of CREB that contains an alternatively spliced exon encoding multiple stop codons. CREB encoded by this transcript is a truncated protein lacking the bZIP domain. We postulated that the antigen detected by CREB antiserum in the cytoplasm of germinal cells is the truncated CREB that must also lack its nuclear translocation signal (NTS). To test this hypothesis we prepared multiple expression plasmids encoding carboxyl-terminal deletions of CREB and transiently expressed them in COS-1 cells. By Western immunoblot analysis as well as immunocytochemistry of transfected cells, we show that CREB proteins truncated to amino acid 286 or shorter are sequestered in the cytoplasm, whereas a CREB of 295 amino acids is translocated into the nucleus. Chimeric CREBs containing a heterologous NTS fused to the first 248 or 261 amino acids of CREB are able to drive the translocation of the protein into the nucleus. Thus, the nine amino acids in the basic region involved in DNA recognition between positions 287 and 295 (RRKKKEYVK) of CREB contain the NTS. Further, mutation of the lysine at position 290 in CREB to an asparagine diminishes nuclear translocation of the protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Measuring limits of telomere movement on nuclear envelope.

The dynamic behavior of the decondensed chromatin can be monitored by real-time fluorescence confocal microscopy. It can be observed that different chromosomal sites enjoy different degrees of freedom during a certain period, exploring larger or smaller portions of nuclear volume. Here we measure the accessible surface for two chromosomal sites (yeast telomeres Tel3R and Tel6R) that both exhibit strong preferential association with the nuclear membrane in galactose-containing media, but differ significantly in gene activity. Telomere Tel6R, which harbors an inducible gene with high levels of transcription, explores a much larger surface than the telomere Tel3R, which is adjacent to inactive chromatin. Thus, our results distinguish two perinuclear movements characteristic of different transcriptional state, allowing for a better understanding of the correlation between activity of genes and chromatin dynamics.

CCL21 is sufficient to mediate DC migration, maturation and function in the absence of CCL19.

Mice deficient in CCR7 signals show severe defects in lymphoid tissue architecture and immune response. These defects are due to impaired attraction of CCR7+ DC and CCR7+ T cells into the T zones of secondary lymphoid organs and altered DC maturation. It is currently unclear which CCR7 ligand mediates these processes in vivo as CCL19 and CCL21 show an overlapping expression pattern and blocking experiments have given contradictory results. In this study, we addressed this question using CCL19-deficient mice expressing various levels of CCL21. Complete deficiency of CCL19 and CCL21 but not CCL19 alone was found to be associated with abnormal frequencies and localization of DC in naïve LN. Similarly, CCL19 was not required for DC migration from the skin, full DC maturation and efficient T-cell priming. Our findings suggest that CCL21 is the critical CCR7 ligand regulating DC homeostasis and function in vivo with CCL19 being redundant for these processes.

Plasma levels of luteinizing hormone and gonadal maturation of lambari females under different photoperiods

The objective of this work was to evaluate the effect of photoperiod on luteinizing hormone (LH) plasma levels and gonadal maturation of lambari females. One hundred and twenty adult lambaris, distributed into 12 aquaria of 20 L each, were randomly subjected to three different treatments, in a completely randomized design, and four replicates. Treatments were photoperiods in hours of light (L) and darkness (D): T1, 0 L:24 D; T2, 12 L:12 D; T3, 24 L:0 D. After 40 days, fish were subjected to fasting for 24 hours and, then, anesthetized. Immediately after slaughter, fish were weighed, and their gonads and livers were removed and weighed. Ovaries were weighed and immersed in Bouin's fixative solution for 24 hours and, then, kept in 70% alcohol until processing the material. Subsequently, the oocyte developmental stage was determined. No significant differences were observed between treatments for final weight, ovary weight, gonadosomatic index (GSI), hepatosomatic index (HSI) and LH levels. In all treatments, lambari females showed maturing ovaries with prevalence of vitellogenic oocytes. Photoperiod does not affect the LH levels and ovarian maturation in lambari females.

Rab3D is critical for secretory granule maturation in PC12 cells.

Neuropeptide- and hormone-containing secretory granules (SGs) are synthesized at the trans-Golgi network (TGN) as immature secretory granules (ISGs) and complete their maturation in the F-actin-rich cell cortex. This maturation process is characterized by acidification-dependent processing of cargo proteins, condensation of the SG matrix and removal of membrane and proteins not destined to mature secretory granules (MSGs). Here we addressed a potential role of Rab3 isoforms in these maturation steps by expressing their nucleotide-binding deficient mutants in PC12 cells. Our data show that the presence of Rab3D(N135I) decreases the restriction of maturing SGs to the F-actin-rich cell cortex, blocks the removal of the endoprotease furin from SGs and impedes the processing of the luminal SG protein secretogranin II. This strongly suggests that Rab3D is implicated in the subcellular localization and maturation of ISGs.

Phylogenetic analysis of plastid and nuclear DNA sequences reveals a rapid late Miocene radiation of the temperate bamboo tribe Arundinarieae (Poaceae, Bambusoideae)

Background: Arundinarieae are a large tribe of temperate woody bamboos for which phylogenetics are poorly understood because of limited taxon sampling and lack of informative characters. Aims: This study assessed phylogenetic relationships, origins and classification of Arundinarieae. Methods: DNA sequences (plastid trnL-F; nuclear ITS) were used for parsimony and Bayesian inference including 41 woody bamboo taxa. Divergence dates were estimated using a relaxed Bayesian clock. Results: Arundinarieae were monophyletic but their molecular divergence was low compared to the tropical Bambuseae. Ancestors of the Arundinarieae lineage were estimated to have diverged from the other bamboos 23 (15-30) million years ago (Mya). However, the Arundinarieae radiation occurred 10 (6-16) Mya compared to 18 (11-25) Mya for the tropical Bambuseae. Some groups could be defined within Arundinarieae, but they do not correspond to recognised subtribes such as Arundinariinae or Shibataeinae. Conclusions: Arundinarieae are a relatively ancient bambusoid lineage that underwent a rapid radiation in the late Miocene. The radiation coincides with the continental collision of the Indo-Australian and Eurasian Plates. Arundinarieae are distributed primarily in East Asia and the Himalayas to northern Southeast Asia. It is unknown whether they were present in Asia long before their radiation, but we believe recent dispersal is a more likely scenario. Keywords: Arundinarieae; Bambuseae; internal transcribed spacer (ITS); molecular clock; phylogenetics; radiation; temperate bamboos; Thamnocalaminae; trnL-F

Childhood cancer and nuclear power plants in Switzerland: a census-based cohort study.

BACKGROUND: Previous studies on childhood cancer and nuclear power plants (NPPs) produced conflicting results. We used a cohort approach to examine whether residence near NPPs was associated with leukaemia or any childhood cancer in Switzerland. METHODS: We computed person-years at risk for children aged 0-15 years born in Switzerland from 1985 to 2009, based on the Swiss censuses 1990 and 2000 and identified cancer cases from the Swiss Childhood Cancer Registry. We geo-coded place of residence at birth and calculated incidence rate ratios (IRRs) with 95% confidence intervals (CIs) comparing the risk of cancer in children born <5 km, 5-10 km and 10-15 km from the nearest NPP with children born >15 km away, using Poisson regression models. RESULTS: We included 2925 children diagnosed with cancer during 21 117 524 person-years of follow-up; 953 (32.6%) had leukaemia. Eight and 12 children diagnosed with leukaemia at ages 0-4 and 0-15 years, and 18 and 31 children diagnosed with any cancer were born <5 km from a NPP. Compared with children born >15 km away, the IRRs (95% CI) for leukaemia in 0-4 and 0-15 year olds were 1.20 (0.60-2.41) and 1.05 (0.60-1.86), respectively. For any cancer, corresponding IRRs were 0.97 (0.61-1.54) and 0.89 (0.63-1.27). There was no evidence of a dose-response relationship with distance (P > 0.30). Results were similar for residence at diagnosis and at birth, and when adjusted for potential confounders. Results from sensitivity analyses were consistent with main results. CONCLUSIONS: This nationwide cohort study found little evidence of an association between residence near NPPs and the risk of leukaemia or any childhood cancer.

Características de tolerância à seca em genótipos de uma coleção nuclear de arroz de terras altas

Resumo:O objetivo deste trabalho foi avaliar características morfofisiológicas relacionadas à tolerância ao estresse hídrico em genótipos de uma coleção nuclear temática de arroz de terras altas, bem como identificar os materiais mais tolerantes. Foram avaliados 100 genótipos de arroz de terras altas em experimentos conduzidos com e sem estresse por deficiência hídrica. Os genótipos tenderam a aumentar o número de dias para o florescimento (FLO) e a diminuir a altura (ALT), na condição de estresse, mas manifestaram ampla variação de comportamento. A esterilidade das espiguetas (EST) foi a característica mais importante para a seleção, nas duas condições de cultivo, em razão de sua elevada correlação negativa com a produtividade. O número de perfilhos não diferiu entre os genótipos na condição sem estresse, mas houve diferença significativa sob estresse hídrico. Os genótipos Ligeiro e Canela de Ferro apresentaram baixos índices de susceptibilidade à seca (ISS), mas baixa produtividade em ambas as condições de cultivo; já os materiais Catetão, Jatobá e Arroz do Maranhão apresentaram elevada produtividade sob estresse e valores de ISS relativamente baixos. EST, FLO, ALT e ISS são características morfofisiológicas relacionadas à tolerância à seca, e os genótipos Catetão, Jatobá e Arroz do Maranhão podem constituir boas fontes de genes para tolerância à seca em programas de melhoramento.

Guiding ligands to nuclear receptors.

Retinoic acid-the active metabolite of vitamin A-influences biological processes by activating the retinoic acid receptor (RAR). In this issue, Schug et al. (2007) demonstrate that retinoic acid also activates the peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta). Remarkably, retinoic acid signaling through RAR or PPARbeta/delta-which depends on cytoplasmic retinoic acid transporters-commits the cell to opposite fates, apoptosis or survival, respectively.