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1.
Ecol Evol ; 14(6): e11455, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38855312

RESUMO

Climate change is predicted to narrow the prescriptive zone of dryland species, potentially leading to behavioural modifications with fitness consequences. This study explores the behavioural responses of three widespread African antelope species-springbok, kudu and eland-to extreme heat in a dryland savanna. We classified the behaviour of 29 individuals during the hot, dry season on the basis of accelerometer data using supervised machine learning and analysed the impact of afternoon heat on behaviour-specific time allocation and overall dynamic body acceleration (ODBA), a proxy for energy expenditure, along with compensatory changes over the 24-hour cycle. Extreme afternoon heat reduced feeding time in all three antelope species, increased ruminating and resting time, while only minimally affecting walking time. With rising heat, all three species reduced ODBA on feeding, while eland reduced and kudu increased ODBA on walking. Diel responses in behaviour differed between species, but were generally characterised by daytime reductions in feeding and increases in ruminating or resting on hot days compared to cool days. While antelope compensated for heat-driven behavioural change over the 24-hour cycle in some cases, significant differences persisted in others, including reduced feeding and increased rumination and resting. The impact of heat on antelope behaviour reveals trade-offs between feeding and thermoregulation, as well as between feeding and rumination, the latter suggesting a strategy to enhance nutrient uptake through increased digestive efficiency, while the walking response suggests narrow constraints between cost and necessity. Our findings suggest that heat influences both behaviour-specific time allocation and energy expenditure. Altered diel behaviour patterns and incomplete compensation over the 24-hour cycle point to fitness consequences. The need to prioritise thermoregulation over feeding is likely to narrow the prescriptive zone of these dryland antelope.

2.
Aesthetic Plast Surg ; 46(Suppl 1): 61-62, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34561726

RESUMO

Breast augmentation is the most commonly performed aesthetic procedure. Transaxillary approach is one of the widely accepted techniques for breast augmentation. It has an advantage of the remote nature of the access incision related to the breasts, thereby reducing the visibility of the scar. This is a letter to the editor of the Aesthetic Plastic Surgery journal about the study by Nguyen and to on comparison of endoscopic transaxillary and periareolar techniques in breast augmentation. We have talked about the advantages of the transaxillary approach compared to other techniques and presented the evidence. We recommend future studies comparing the transaxillary, periareolar, and inframammary approaches for breast augmentation with a large cohort and systematic reviews on the same topic. Studies can also be done by combining the cell-assisted lipotransfer with fat graft and endoscopic transaxillary approach for breast augmentation to determine if it provides the best outcome with minimal complications.Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .


Assuntos
Implante Mamário , Implantes de Mama , Mamoplastia , Mama/cirurgia , Implante Mamário/métodos , Estética , Humanos , Mamoplastia/métodos , Estudos Retrospectivos , Resultado do Tratamento
3.
Nat Ecol Evol ; 5(6): 757-767, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33795854

RESUMO

The forests of Amazonia are among the most biodiverse plant communities on Earth. Given the immediate threats posed by climate and land-use change, an improved understanding of how this extraordinary biodiversity is spatially organized is urgently required to develop effective conservation strategies. Most Amazonian tree species are extremely rare but a few are common across the region. Indeed, just 227 'hyperdominant' species account for >50% of all individuals >10 cm diameter at 1.3 m in height. Yet, the degree to which the phenomenon of hyperdominance is sensitive to tree size, the extent to which the composition of dominant species changes with size class and how evolutionary history constrains tree hyperdominance, all remain unknown. Here, we use a large floristic dataset to show that, while hyperdominance is a universal phenomenon across forest strata, different species dominate the forest understory, midstory and canopy. We further find that, although species belonging to a range of phylogenetically dispersed lineages have become hyperdominant in small size classes, hyperdominants in large size classes are restricted to a few lineages. Our results demonstrate that it is essential to consider all forest strata to understand regional patterns of dominance and composition in Amazonia. More generally, through the lens of 654 hyperdominant species, we outline a tractable pathway for understanding the functioning of half of Amazonian forests across vertical strata and geographical locations.


Assuntos
Florestas , Árvores , Biodiversidade , Brasil , Humanos
4.
Sensors (Basel) ; 20(3)2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31991710

RESUMO

The problem of obtaining high range resolution (HRR) profiles for non-cooperative target recognition by coherently combining data from narrowband radars was investigated using sparse reconstruction techniques. If the radars concerned operate within different frequency bands, then this process increases the overall effective bandwidth and consequently enhances resolution. The case of unknown range offsets occurring between the radars' range profiles due to incorrect temporal and spatial synchronisation between the radars was considered, and the use of both pruned orthogonal matching pursuit and refined l 1 -norm regularisation solvers was explored to estimate the offsets between the radars' channels so as to attain the necessary coherence for combining their data. The proposed techniques were demonstrated and compared using simulated radar data.

5.
Sensors (Basel) ; 19(24)2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31847207

RESUMO

This paper introduces a new approach to bistatic radar tomographic imaging based on the concept of compressive sensing and sparse reconstruction. The field of compressive sensing has established a mathematical framework which guarantees sparse solutions for under-determined linear inverse problems. In this paper, we present a new formulation for the bistatic radar tomography problem based on sparse inversion, moving away from the conventional k-space tomography approach. The proposed sparse inversion approach allows high-quality images of the target to be obtained from limited narrowband radar data. In particular, we exploit the use of the parameter-refined orthogonal matching pursuit (PROMP) algorithm to obtain a sparse solution for the sparse-based tomography formulation. A key important feature of the PROMP algorithm is that it is capable of tackling the dictionary mismatch problem arising from off-grid scatterers by perturbing the dictionary atoms and allowing them to go off the grid. Performance evaluation studies involving both simulated and real data are presented to demonstrate the performance advantage of the proposed sparsity-based tomography method over the conventional k-space tomography method.

6.
Ecol Evol ; 8(16): 8523-8536, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30250720

RESUMO

Woody perennial plants on islands have repeatedly evolved from herbaceous mainland ancestors. Although the majority of species in Euphorbia subgenus Chamaesyce section Anisophyllum (Euphorbiaceae) are small and herbaceous, a clade of 16 woody species diversified on the Hawaiian Islands. They are found in a broad range of habitats, including the only known C4 plants adapted to wet forest understories. We investigate the history of island colonization and habitat shift in this group. We sampled 153 individuals in 15 of the 16 native species of Hawaiian Euphorbia on six major Hawaiian Islands, plus 11 New World close relatives, to elucidate the biogeographic movement of this lineage within the Hawaiian island chain. We used a concatenated chloroplast DNA data set of more than eight kilobases in aligned length and applied maximum likelihood and Bayesian inference for phylogenetic reconstruction. Age and phylogeographic patterns were co-estimated using BEAST. In addition, we used nuclear ribosomal ITS and the low-copy genes LEAFY and G3pdhC to investigate the reticulate relationships within this radiation. Hawaiian Euphorbia first arrived on Kaua`i or Ni`ihau ca. 5 million years ago and subsequently diverged into 16 named species with extensive reticulation. During this process Hawaiian Euphorbia dispersed from older to younger islands through open vegetation that is disturbance-prone. Species that occur under closed vegetation evolved in situ from open vegetation of the same island and are only found on the two oldest islands of Kaua`i and O`ahu. The biogeographic history of Hawaiian Euphorbia supports a progression rule with within-island shifts from open to closed vegetation.

7.
Sensors (Basel) ; 18(6)2018 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-29874878

RESUMO

This paper presents a new image focusing algorithm for sparsity-driven radar imaging of rotating targets. In the general formulation of off-grid scatterers, the sparse reconstruction algorithms may result in blurred and low-contrast images due to dictionary mismatch. Motivated by the natural clustering of atoms in the sparsity-based reconstructed images, the proposed algorithm first partitions the atoms into separate clusters, and then the true off-grid scatterers associated with each cluster are estimated. Being a post-processing technique, the proposed algorithm is computationally simple, while at the same time being capable of producing a sharp and correct-contrast image, and attaining a scatterer parameter estimation performance close to the Cramér⁻Rao lower bound. Numerical simulations are presented to corroborate the effectiveness of the proposed algorithm.

8.
Science ; 358(6370): 1614-1617, 2017 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-29269477

RESUMO

The cataloging of the vascular plants of the Americas has a centuries-long history, but it is only in recent decades that an overview of the entire flora has become possible. We present an integrated assessment of all known native species of vascular plants in the Americas. Twelve regional and national checklists, prepared over the past 25 years and including two large ongoing flora projects, were merged into a single list. Our publicly searchable checklist includes 124,993 species, 6227 genera, and 355 families, which correspond to 33% of the 383,671 vascular plant species known worldwide. In the past 25 years, the rate at which new species descriptions are added has averaged 744 annually for the Americas, and we can expect the total to reach about 150,000.

9.
Ann Bot ; 119(4): 563-579, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28065919

RESUMO

Background and Aims: Wood is a major innovation of land plants, and is usually a central component of the body plan for two major plant habits: shrubs and trees. Wood anatomical syndromes vary between shrubs and trees, but no prior work has explicitly evaluated the contingent evolution of wood anatomical diversity in the context of these plant habits. Methods: Phylogenetic comparative methods were used to test for contingent evolution of habit, habitat and wood anatomy in the mega-diverse genus Croton (Euphorbiaceae), across the largest and most complete molecular phylogeny of the genus to date. Key Results: Plant habit and habitat are highly correlated, but most wood anatomical features correlate more strongly with habit. The ancestral Croton was reconstructed as a tree, the wood of which is inferred to have absent or indistinct growth rings, confluent-like axial parenchyma, procumbent ray cells and disjunctive ray parenchyma cell walls. The taxa sampled showed multiple independent origins of the shrub habit in Croton , and this habit shift is contingent on several wood anatomical features (e.g. similar vessel-ray pits, thick fibre walls, perforated ray cells). The only wood anatomical trait correlated with habitat and not habit was the presence of helical thickenings in the vessel elements of mesic Croton . Conclusions: Plant functional traits, individually or in suites, are responses to multiple and often confounding contexts in evolution. By establishing an explicit contingent evolutionary framework, the interplay between habit, habitat and wood anatomical diversity was dissected in the genus Croton . Both habit and habitat influence the evolution of wood anatomical characters, and conversely, the wood anatomy of lineages can affect shifts in plant habit and habitat. This study hypothesizes novel putatively functional trait associations in woody plant structure that could be further tested in a variety of other taxa.


Assuntos
Evolução Biológica , Croton/anatomia & histologia , Árvores/anatomia & histologia , Madeira/anatomia & histologia , Biodiversidade , Ecossistema , Filogenia
10.
PhytoKeys ; (90): 1-87, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29391851

RESUMO

All published names of Croton from Madagascar, the Comoros, and the Mascarenes are treated here. We indicate which names are currently accepted (123 native species and 1 introduced), which ones we consider to be heterotypic synonyms (188), which ones are doubtful (25), and which ones should be excluded (5). We newly designate lectotypes for 108 names, and epitypes for C. anisatus Baill., C. nobilis Baill., and C. submetallicus Baill. A total of 133 names are newly treated as synonyms. One new combination is made, Croton basaltorum (Leandri) P.E.Berry for C. antanosiensis var. basaltorum Leandri, and one new name is proposed, Croton toliarensis B.W.vanEe & Kainul. for C. tranomarensis var. rosmarinifolius Radcl.-Sm.

11.
Evolution ; 68(12): 3485-504, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25302554

RESUMO

The mid-Cenozoic decline of atmospheric CO2 levels that promoted global climate change was critical to shaping contemporary arid ecosystems. Within angiosperms, two CO2 -concentrating mechanisms (CCMs)-crassulacean acid metabolism (CAM) and C4 -evolved from the C3 photosynthetic pathway, enabling more efficient whole-plant function in such environments. Many angiosperm clades with CCMs are thought to have diversified rapidly due to Miocene aridification, but links between this climate change, CCM evolution, and increased net diversification rates (r) remain to be further understood. Euphorbia (∼2000 species) includes a diversity of CAM-using stem succulents, plus a single species-rich C4 subclade. We used ancestral state reconstructions with a dated molecular phylogeny to reveal that CCMs independently evolved 17-22 times in Euphorbia, principally from the Miocene onwards. Analyses assessing among-lineage variation in r identified eight Euphorbia subclades with significantly increased r, six of which have a close temporal relationship with a lineage-corresponding CCM origin. Our trait-dependent diversification analysis indicated that r of Euphorbia CCM lineages is approximately threefold greater than C3 lineages. Overall, these results suggest that CCM evolution in Euphorbia was likely an adaptive strategy that enabled the occupation of increased arid niche space accompanying Miocene expansion of arid ecosystems. These opportunities evidently facilitated recent, replicated bursts of diversification in Euphorbia.


Assuntos
Euphorbia/genética , Evolução Molecular , Fotossíntese , Euphorbia/classificação , Euphorbia/fisiologia , Filogenia
12.
ScientificWorldJournal ; 2014: 209752, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24526883

RESUMO

The susceptibility of railway wheels to wear and rolling contact fatigue damage is influenced by the properties of the wheel material. These are influenced by the steel composition, wheel manufacturing process, and thermal and mechanical loading during operation. The in-service properties therefore vary with depth below the surface and with position across the wheel tread. This paper discusses the stress history at the wheel/rail contact (derived from dynamic simulations) and observed variations in hardness and microstructure. It is shown that the hardness of an "in-service" wheel rim varies significantly, with three distinct effects. The underlying hardness trend with depth can be related to microstructural changes during manufacturing (proeutectoid ferrite fraction and pearlite lamellae spacing). The near-surface layer exhibits plastic flow and microstructural shear, especially in regions which experience high tangential forces when curving, with consequentially higher hardness values. Between 1 mm and 7 mm depth, the wheel/rail contacts cause stresses exceeding the material yield stress, leading to work hardening, without a macroscopic change in microstructure. These changes in material properties through the depth of the wheel rim would tend to increase the likelihood of crack initiation on wheels toward the end of their life. This correlates with observations from several train fleets.


Assuntos
Dureza , Aço , Teste de Materiais , Modelos Teóricos
13.
Mol Phylogenet Evol ; 71: 55-78, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24513576

RESUMO

We present an integrative model predicting associations among epiphytism, the tank habit, entangling seeds, C3 vs. CAM photosynthesis, avian pollinators, life in fertile, moist montane habitats, and net rates of species diversification in the monocot family Bromeliaceae. We test these predictions by relating evolutionary shifts in form, physiology, and ecology to time and ancestral distributions, quantifying patterns of correlated and contingent evolution among pairs of traits and analyzing the apparent impact of individual traits on rates of net species diversification and geographic expansion beyond the ancestral Guayana Shield. All predicted patterns of correlated evolution were significant, and the temporal and spatial associations of phenotypic shifts with orogenies generally accorded with predictions. Net rates of species diversification were most closely coupled to life in fertile, moist, geographically extensive cordilleras, with additional significant ties to epiphytism, avian pollination, and the tank habit. The highest rates of net diversification were seen in the bromelioid tank-epiphytic clade (D(crown) = 1.05 My⁻¹), associated primarily with the Serra do Mar and nearby ranges of coastal Brazil, and in the core tillandsioids (D(crown) = 0.67 My⁻¹), associated primarily with the Andes and Central America. Six large-scale adaptive radiations and accompanying pulses of speciation account for 86% of total species richness in the family. This study is among the first to test a priori hypotheses about the relationships among phylogeny, phenotypic evolution, geographic spread, and net species diversification, and to argue for causality to flow from functional diversity to spatial expansion to species diversity.


Assuntos
Adaptação Biológica , Bromeliaceae/genética , Filogenia , Biodiversidade , América Latina , Sudoeste dos Estados Unidos
14.
Br J Nurs ; 22(19): S20-2, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24350395

RESUMO

This article has been written to highlight the licensed use of winged infusion devices for short-term intravenous (IV) therapy. There is limited published literature on the subject, yet this clinical audit has demonstrated that the use of winged infusion devices has clear advantages for patients and nurses. The audit was conducted in the community setting but could be replicated in any community or hospital environment where short-term intravenous therapy of nonvesicant fluids are administered. For the purpose of this audit, nonvesicant antibiotics were administered.


Assuntos
Infusões Intravenosas/instrumentação , Medicina Estatal , Reino Unido
15.
Br J Nurs ; 22(19 Suppl): S20-2, 2013 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-24165789

RESUMO

This article has been written to highlight the licensed use of winged infusion devices for short-term intravenous (IV) therapy. There is limited published literature on the subject, yet this clinical audit has demonstrated that the use of winged infusion devices has clear advantages for patients and nurses. The audit was conducted in the community setting but could be replicated in any community or hospital environment where short-term intravenous therapy of non-vesicant fluids are administered. For the purpose of this audit, non-vesicant antibiotics were administered.


Assuntos
Hospitais , Infusões Intravenosas , Humanos
16.
Cancer Res ; 73(16): 5288-98, 2013 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-23824741

RESUMO

Interleukin (IL)-6 overexpression and constitutive STAT3 activation occur in many cancers, including prostate cancer. However, their contribution to prostate stem and progenitor cells has not been explored. In this study, we show that stem-like cells from patients with prostate cancer secrete higher levels of IL-6 than their counterparts in non-neoplastic prostate. Tumor grade did not influence the levels of expression or secretion. Stem-like and progenitor cells expressed the IL-6 receptor gp80 with concomitant expression of pSTAT3. Blockade of activated STAT3, by either anti-IL-6 antibody siltuximab (CNTO 328) or LLL12, a specific pSTAT3 inhibitor, suppressed the clonogenicity of the stem-like cells in patients with high-grade disease. In a murine xenograft model used to determine the in vivo effects of pSTAT3 suppression, LLL12 treatment effectively abolished outgrowth of a patient-derived castrate-resistant tumor. Our results indicate that the most primitive cells in prostate cancer require pSTAT3 for survival, rationalizing STAT3 as a therapeutic target to treat advanced prostate cancer.


Assuntos
Janus Quinases/antagonistas & inibidores , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Neoplasias de Próstata Resistentes à Castração/metabolismo , Neoplasias de Próstata Resistentes à Castração/patologia , Fator de Transcrição STAT3/antagonistas & inibidores , Fator de Transcrição STAT3/genética , Idoso , Idoso de 80 Anos ou mais , Animais , Antraquinonas/farmacologia , Anticorpos Monoclonais/farmacologia , Linhagem Celular Tumoral , Humanos , Interleucina-6/genética , Interleucina-6/metabolismo , Janus Quinases/genética , Janus Quinases/metabolismo , Masculino , Camundongos , Pessoa de Meia-Idade , Células-Tronco Neoplásicas/efeitos dos fármacos , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , Receptores de Interleucina-6/genética , Receptores de Interleucina-6/metabolismo , Fator de Transcrição STAT3/metabolismo , Sulfonamidas/farmacologia
17.
Mol Phylogenet Evol ; 63(2): 305-26, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22273597

RESUMO

Euphorbia is among the largest genera of angiosperms, with about 2000 species that are renowned for their remarkably diverse growth forms. To clarify phylogenetic relationships in the genus, we used maximum likelihood, bayesian, and parsimony analyses of DNA sequence data from 10 markers representing all three plant genomes, averaging more than 16kbp for each accession. Taxon sampling included 176 representatives from Euphorbioideae (including 161 of Euphorbia). Analyses of these data robustly resolve a backbone topology of four major, subgeneric clades--Esula, Rhizanthium, Euphorbia, and Chamaesyce--that are successively sister lineages. Ancestral state reconstructions of six reproductive and growth form characters indicate that the earliest Euphorbia species were likely woody, non-succulent plants with helically arranged leaves and 5-glanded cyathia in terminal inflorescences. The highly modified growth forms and reproductive features in Euphorbia have independent origins within the subgeneric clades. Examples of extreme parallelism in trait evolution include at least 14 origins of xeromorphic growth forms and at least 13 origins of seed caruncles. The evolution of growth form and inflorescence position are significantly correlated, and a pathway of evolutionary transitions is supported that has implications for the evolution of Euphorbia xerophytes of large stature. Such xerophytes total more than 400 species and are dominants of vegetation types throughout much of arid Africa and Madagascar.


Assuntos
Euphorbia , Filogenia , Folhas de Planta/anatomia & histologia , Sementes/anatomia & histologia , Sementes/genética , Sequência de Bases , Evolução Biológica , Euphorbia/anatomia & histologia , Euphorbia/classificação , Euphorbia/genética , Evolução Molecular , Marcadores Genéticos , Genoma de Planta , Dados de Sequência Molecular , Análise de Sequência de DNA
18.
Am J Bot ; 98(9): 1486-503, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21875975

RESUMO

PREMISE OF THE STUDY: The Chamaesyce clade of Euphorbia is the largest lineage of C(4) plants among the eudicots, with 350 species including both narrow endemics and cosmopolitan weeds. We sampled this group worldwide to address questions about subclade relationships, the origin of C(4) photosynthesis, the evolution of weeds, and the role of hybridization and long-distance dispersal in the diversification of the group. • METHODS: Two nuclear (ITS and exon 9 of EMB2765) and three chloroplast markers (matK, rpl16, and trnL-F) were sequenced for 138 ingroup and six outgroup species. Exon 9 of EMB2765 was cloned in accessions with >1% superimposed peaks. • KEY RESULTS: The Chamaesyce clade is monophyletic and consists of three major subclades [1(2,3)]: (1) the Acuta clade, containing three North American species with C(3) photosynthesis and C(3)-C(4) intermediates; (2) the Peplis clade, mostly North American and entirely C(4); and (3) the Hypericifolia clade, all C(4), with both New World and Old World groups. Incongruence between chloroplast and ITS phylogenies and divergent cloned copies of EMB2765 exon 9 suggest extensive hybridization, especially in the Hawaiian Islands radiation. • CONCLUSIONS: The Chamaesyce clade originated in warm, arid areas of North America, where it evolved C(4) photosynthesis. From there, it diversified globally with extensive reticulate evolution and frequent long-distance dispersals. Although many species are weedy, there are numerous local adaptations to specific substrates and regional or island radiations, which have contributed to the great diversity of this group.


Assuntos
Euphorbia/genética , Evolução Molecular , Filogenia , Sequência de Bases , Primers do DNA , DNA de Plantas/genética , Euphorbia/classificação , Éxons , Genes de Plantas , Reação em Cadeia da Polimerase , Homologia de Sequência do Ácido Nucleico
19.
Mol Cancer ; 10: 94, 2011 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-21801380

RESUMO

BACKGROUND: Epigenetic control is essential for maintenance of tissue hierarchy and correct differentiation. In cancer, this hierarchical structure is altered and epigenetic control deregulated, but the relationship between these two phenomena is still unclear. CD133 is a marker for adult stem cells in various tissues and tumour types. Stem cell specificity is maintained by tight regulation of CD133 expression at both transcriptional and post-translational levels. In this study we investigated the role of epigenetic regulation of CD133 in epithelial differentiation and cancer. METHODS: DNA methylation analysis of the CD133 promoter was done by pyrosequencing and methylation specific PCR; qRT-PCR was used to measure CD133 expression and chromatin structure was determined by ChIP. Cells were treated with DNA demethylating agents and HDAC inhibitors. All the experiments were carried out in both cell lines and primary samples. RESULTS: We found that CD133 expression is repressed by DNA methylation in the majority of prostate epithelial cell lines examined, where the promoter is heavily CpG hypermethylated, whereas in primary prostate cancer and benign prostatic hyperplasia, low levels of DNA methylation, accompanied by low levels of mRNA, were found. Moreover, differential methylation of CD133 was absent from both benign or malignant CD133+/α2ß1integrinhi prostate (stem) cells, when compared to CD133-/α2ß1integrinhi (transit amplifying) cells or CD133-/α2ß1integrinlow (basal committed) cells, selected from primary epithelial cultures. Condensed chromatin was associated with CD133 downregulation in all of the cell lines, and treatment with HDAC inhibitors resulted in CD133 re-expression in both cell lines and primary samples. CONCLUSIONS: CD133 is tightly regulated by DNA methylation only in cell lines, where promoter methylation and gene expression inversely correlate. This highlights the crucial choice of cell model systems when studying epigenetic control in cancer biology and stem cell biology. Significantly, in both benign and malignant prostate primary tissues, regulation of CD133 is independent of DNA methylation, but is under the dynamic control of chromatin condensation. This indicates that CD133 expression is not altered in prostate cancer and it is consistent with an important role for CD133 in the maintenance of the hierarchical cell differentiation patterns in cancer.


Assuntos
Células-Tronco Adultas/metabolismo , Antígenos CD/genética , Diferenciação Celular/genética , Células Epiteliais/fisiologia , Glicoproteínas/genética , Neoplasias/genética , Peptídeos/genética , Regiões Promotoras Genéticas , Antígeno AC133 , Células-Tronco Adultas/fisiologia , Animais , Antígenos CD/metabolismo , Biomarcadores/análise , Biomarcadores/metabolismo , Linhagem Celular Tumoral , Metilação de DNA/fisiologia , Células Epiteliais/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação Neoplásica da Expressão Gênica , Glicoproteínas/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Camundongos Transgênicos , Neoplasias/metabolismo , Neoplasias/patologia , Peptídeos/metabolismo , Hiperplasia Prostática/genética , Hiperplasia Prostática/metabolismo , Hiperplasia Prostática/patologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Transplante Heterólogo
20.
Am J Bot ; 98(5): 872-95, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21613186

RESUMO

PREMISE: Bromeliaceae form a large, ecologically diverse family of angiosperms native to the New World. We use a bromeliad phylogeny based on eight plastid regions to analyze relationships within the family, test a new, eight-subfamily classification, infer the chronology of bromeliad evolution and invasion of different regions, and provide the basis for future analyses of trait evolution and rates of diversification. METHODS: We employed maximum-parsimony, maximum-likelihood, and Bayesian approaches to analyze 9341 aligned bases for four outgroups and 90 bromeliad species representing 46 of 58 described genera. We calibrate the resulting phylogeny against time using penalized likelihood applied to a monocot-wide tree based on plastid ndhF sequences and use it to analyze patterns of geographic spread using parsimony, Bayesian inference, and the program S-DIVA. RESULTS: Bromeliad subfamilies are related to each other as follows: (Brocchinioideae, (Lindmanioideae, (Tillandsioideae, (Hechtioideae, (Navioideae, (Pitcairnioideae, (Puyoideae, Bromelioideae))))))). Bromeliads arose in the Guayana Shield ca. 100 million years ago (Ma), spread centrifugally in the New World beginning ca. 16-13 Ma, and dispersed to West Africa ca. 9.3 Ma. Modern lineages began to diverge from each other roughly 19 Ma. CONCLUSIONS: Nearly two-thirds of extant bromeliads belong to two large radiations: the core tillandsioids, originating in the Andes ca. 14.2 Ma, and the Brazilian Shield bromelioids, originating in the Serro do Mar and adjacent regions ca. 9.1 Ma.


Assuntos
Bromeliaceae/genética , Evolução Molecular , Filogenia , Plastídeos/genética , Teorema de Bayes , Evolução Biológica , Bromeliaceae/classificação , DNA de Plantas/genética , Genes de Plantas , Funções Verossimilhança , Dados de Sequência Molecular , NADH Desidrogenase/genética , Proteínas de Plantas/genética , Alinhamento de Sequência , Análise de Sequência de DNA
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