Changes in Epigaeic Ant Assemblage Structure in the Amazon during Successional Processes after Bauxite Mining

Environmental impact studies often involve monitoring and using bioindicators to evaluate the restoration stage of impacted areas. We aimed to assess ant assemblages’ response to the ecological succession of previously disturbed areas in the Brazilian Amazon. We sampled epigeic ant assemblages in five bauxite mining areas, representing different restoration stages, and compared them with two pristine areas. We also compared trends in species richness at the same mine site investigated 14 years earlier. Ten pitfall traps and four Winkler samples of litter were taken along a 100-m transect in each area. We expected that ant species richness would increase with the amelioration in habitat condition (i.e., environmental surrogates of ecological succession, including litter depth, soil penetrability, the circumference of trees, the distance of trees to adjacent trees, and percentage of ground cover). We also compared the efficacy of both sampling methods. Due to more significant sampling effort, pitfall traps captured more ant species than Winkler sacks. However, Winkler samples’ addition allowed the collection of more cryptic species than by pitfall traps alone. We sampled a total of 129 ant species, with increases in ant species richness in more mature rehabilitation. Nevertheless, similarity analysis indicated a significant difference between ant assemblages of rehabilitated areas and pristine ones. Assemblages differed mainly by the presence of specialist and rare species, found only in pristine plots. Rehabilitated areas exhibited a significant increase in tree circumference as they reached more ecologically advanced stages, which contributed to increasing ant species richness. These trends and comparison with the earlier study indicate that although there are favorable increases in ant species richness, in terms of species composition, rehabilitated areas were far from achieving an ant assemblage composition or environmental status that closely resembles pristine areas

Crescimento, defesas e herbivoria em folhas jovens de Qualea parviflora (Vochysiaceae) em três diferentes habitats de Cerrado

Insect herbivory is strongly influenced by the properties of their host leaves. Otherwise, such influence may be mediated by the environment in which the host plant is found. We examined three characteristics that may influence insect herbivory on young leaves of Qualea parviflora Mart. (Vochysiaceae), a widespread tree of the Brazilian Cerrado: leaf expansion rate, sclerophylly (leaf toughness), and tannin concentration during four consecutive months. Herbivory rates were measured on four marked intact leaves in five trees in three different physiognomies of the Cerrado biome: campo sujo (grassland), cerrado sensu stricto (savanna), and cerradão (woodland). Sclerophylly was higher in February while the highest concentration of tannins occurred in November but no variation in the rates of herbivory among months and physiognomies was found. A tendency of higher mean leaf growth rates was observed in the “cerradao” (1.03%) and “cerrado” (1.04%) in comparison with the campo sujo trees (0.86%). Higher sclerophylly and lower expansion rates and leaf size were observed in trees of the campo sujo. There was a tendency for higher herbivory rates in cerrado (10.5%), where the leaves showed lower concentration of tannins (1.5%) than in cerradão (2.1%). New leaves of Q. parviflora showed higher tannins concentration and lower damage than fully expanded leaves. Final leaf area explained 24% of the variation in total herbivory. Leaf size and associated nutritional factors exerted stronger influence on herbivory than defensive compounds on young leaves of Q. parviflora. Key words: Cerrado, leaf age, leaf growth, Neotropical savanna, plant defenses, sclerophylly.A herbivoria por insetos é fortemente influenciada pelas propriedades das folhas hospedeiras. No entanto, esta influência pode ser mediada por condições ambientais do habitat da planta. Neste estudo foram examinadas três características que podem influenciar a herbívora por insetos em folhas jovens de Qualea parvifl ora Mart. (Vochysiaceae), uma árvore comum do Cerrado brasileiro: taxa de expansão foliar, esclerofilia (rigidez foliar) e concentração de taninos. As taxas de herbívora foram medidas em quatro folhas intactas de cinco árvores em três diferentes fitofisionomias do bioma Cerrado: “campo sujo”, “cerrado sensu stricto” e “cerradão”. A esclerofilia foi maior em Fevereiro enquanto altas concentrações de taninos ocorreram em Novembro. No entanto, não foi observada variação nas taxas de herbívora entre os meses e entre fisionomias. Uma tendência em maiores taxas de crescimento foliar foi observada em árvores ocorrentes no “cerradão” (1,03%) e no “cerrado” (1,04%) em comparação com as ocorrentes no “campo sujo” (0,86%). Maiores valores de esclerofilia, baixas taxas de expansão foliar e menor tamanho foliar foram observadas no “campo sujo”. Houve uma tendência em altas taxas de herbívora no “cerrado” (10,5%), onde as folhas apresentaram concentrações de taninos mais baixas (1,5%) que no “cerradão” (2,1%). As folhas jovens de Q. parviflora apresentaram maiores concentrações de taninos e menor dano por herbívora que folhas maduras. A área foliar final explicou 24% da variação da herbívora total. O tamanho das folhas e fatores nutricionais associados exerceram influências mais fortes na herbívora que a concentração de compostos de defesa em folhas jovens de Q. parviflora. Palavras-chave: Cerrado, crescimento foliar, defesa de plantas, esclerofilia, idade foliar, savana neotropical

Gene expression profiling identifies inflammation and angiogenesis as distinguishing features of canine hemangiosarcoma

<p>Abstract</p> <p>Background</p> <p>The etiology of hemangiosarcoma remains incompletely understood. Its common occurrence in dogs suggests predisposing factors favor its development in this species. These factors could represent a constellation of heritable characteristics that promote transformation events and/or facilitate the establishment of a microenvironment that is conducive for survival of malignant blood vessel-forming cells. The hypothesis for this study was that characteristic molecular features distinguish hemangiosarcoma from non-malignant endothelial cells, and that such features are informative for the etiology of this disease.</p> <p>Methods</p> <p>We first investigated mutations of VHL and Ras family genes that might drive hemangiosarcoma by sequencing tumor DNA and mRNA (cDNA). Protein expression was examined using immunostaining. Next, we evaluated genome-wide gene expression profiling using the Affymetrix Canine 2.0 platform as a global approach to test the hypothesis. Data were evaluated using routine bioinformatics and validation was done using quantitative real time RT-PCR.</p> <p>Results</p> <p>Each of 10 tumor and four non-tumor samples analyzed had wild type sequences for these genes. At the genome wide level, hemangiosarcoma cells clustered separately from non-malignant endothelial cells based on a robust signature that included genes involved in inflammation, angiogenesis, adhesion, invasion, metabolism, cell cycle, signaling, and patterning. This signature did not simply reflect a cancer-associated angiogenic phenotype, as it also distinguished hemangiosarcoma from non-endothelial, moderately to highly angiogenic bone marrow-derived tumors (lymphoma, leukemia, osteosarcoma).</p> <p>Conclusions</p> <p>The data show that inflammation and angiogenesis are important processes in the pathogenesis of vascular tumors, but a definitive ontogeny of the cells that give rise to these tumors remains to be established. The data do not yet distinguish whether functional or ontogenetic plasticity creates this phenotype, although they suggest that cells which give rise to hemangiosarcoma modulate their microenvironment to promote tumor growth and survival. We propose that the frequent occurrence of canine hemangiosarcoma in defined dog breeds, as well as its similarity to homologous tumors in humans, offers unique models to solve the dilemma of stem cell plasticity and whether angiogenic endothelial cells and hematopoietic cells originate from a single cell or from distinct progenitor cells.</p

Ants in Burned and Unburned Areas in Campos Rupestres Ecosystem

Ground-dwelling ants have shown consistent resilience to fire in savanna environments. We carried out a study to investigate how ant community structure responds to fire in a harsh and fragile Cerrado ecosystem, the campos rupestres. We studied the change in the ant communities on a local scale subjected to fire in two rocky outcrop habitats at two different elevations (800m above sea level and 1300m a.s.l.). Pitfall trap samples were set at three different periods after a fire event: one, four, and ten months later. Overall, one hundred and fifteen ant species were collected. On a local scale, at the altitude of 800 m asl, no difference in richness and composition of the ant community was found between burned and control plots, whereas at 1300 m asl the burned areas showed higher richness and different ant composition in comparison to control areas.  Differences were clear in the rainy period, four months after the fire. Ten months later, no difference between the richness of ant species in burned and unburned plots was found at higher altitudes, even though the plots showed distinct species composition. These data support the hypothesis that fire must be a structuring disturbance factor for some groups in the ant assemblages and indicate that ant community structure at higher elevations is somehow influenced by the recover of the campos rupestre vegetation

Fenologia reprodutiva, sazonalidade e germinação de Kielmeyera regalis Saddi (Clusiaceae), espécie endêmica dos campos rupestres da Cadeia do Espinhaço, Brasil Reproductive phenology, seasonality and germination of Kielmeyera regalis Saddi (Clusiaceae), a species endemic to rock outcrops in the Espinhaço Range, Brazil

A fenologia reprodutiva e a germinação de sementes foram estudadas em uma população de Kielmeyera regalis da Serra do Cipó, MG. Foram calculados os índices de atividade e intensidade de produção de botões, flores, frutos imaturos e frutos maduros ao longo de 2001. A influência do clima sobre a fenologia foi avaliada por Análise de Correspondência Canônica (CCA). A germinação foi avaliada a temperaturas constantes de 15-35 ºC (com intervalos de 5 ºC) em câmaras de germinação com fotoperíodo de 12 h. A variância dos dados explicada pela CCA foi de 72,8%. A temperatura média do ar, evaporação e radiação solar global apresentaram altos coeficientes de correlação com a fenologia. O florescimento ocorreu nos meses quentes e úmidos, a maturação de frutos se estendeu na estação seca e fria, e a dispersão das sementes, logo antes da estação chuvosa. A germinabilidade foi superior a 80% nas temperaturas de 20-30 ºC, faixa ocorrente no período chuvoso logo após a dispersão das sementes. Comparações com outros estudos indicam que a dispersão e rápida germinação nesses períodos são fortes fatores adaptativos dentro do gênero. Os resultados são importantes para a compreensão dos fatores que afetam o sucesso reprodutivo e expansão populacional, e devem ser considerados para ações de manejo desta espécie rupestre endêmica.<br>The reproductive phenology and seed germination of a Kielmeyera regalis population, from Serra do Cipó (MG), Brazil, were studied. During 2001, the intensity and activity indices were calculated to estimate production of flower buds, flowers, and immature and mature fruits. Influence of the climate on phenology was determined by a Canonical Correspondence Analysis (CCA). Germination was studied under a 12 h photoperiod at seven fixed temperatures (15-35ºC at 5ºC intervals). The CCA explained 72.8% of the phenological data variation. The highest correlation coefficients with phenology were observed for mean air temperature, evaporation and solar global radiation. Flowering occurred during the hot and wet season, fruit maturation extended during the entire cold and dry season, and seed dispersal peaked before the onset of the rainy season. Germinability reached values above 80% under temperatures of 20-30ºC, which occurred during the rainy period, just after seed dispersal. The results of this and other studies indicate that seed dispersal just before the rainy season, and fast germination at the beginning of the rainy season, are highly adaptive traits within the genus. In addition, the results provide important information for understanding basic factors that affect reproductive success and population growth, and should be considered when managing this endemic species from rock outcrop

Bridging big data: procedures for combining non-equivalent cognitive measures from the ENIGMA Consortium

Investigators in the cognitive neurosciences have turned to Big Data to address persistent replication and reliability issues by increasing sample sizes, statistical power, and representativeness of data. While there is tremendous potential to advance science through open data sharing, these efforts unveil a host of new questions about how to integrate data arising from distinct sources and instruments. We focus on the most frequently assessed area of cognition - memory testing - and demonstrate a process for reliable data harmonization across three common measures. We aggregated raw data from 53 studies from around the world which measured at least one of three distinct verbal learning tasks, totaling N = 10,505 healthy and brain-injured individuals. A mega analysis was conducted using empirical bayes harmonization to isolate and remove site effects, followed by linear models which adjusted for common covariates. After corrections, a continuous item response theory (IRT) model estimated each individual subject’s latent verbal learning ability while accounting for item difficulties. Harmonization significantly reduced inter-site variance by 37% while preserving covariate effects. The effects of age, sex, and education on scores were found to be highly consistent across memory tests. IRT methods for equating scores across AVLTs agreed with held-out data of dually-administered tests, and these tools are made available for free online. This work demonstrates that large-scale data sharing and harmonization initiatives can offer opportunities to address reproducibility and integration challenges across the behavioral sciences