Intracellular and extracellular TGF-β signaling in cancer: some recent topics / 医学前沿

Transforming growth factor (TGF)-β regulates a wide variety of cellular responses, including cell growth arrest, apoptosis, cell differentiation, motility, invasion, extracellular matrix production, tissue fibrosis, angiogenesis, and immune function. Although tumor-suppressive roles of TGF-β have been extensively studied and well-characterized in many cancers, especially at early stages, accumulating evidence has revealed the critical roles of TGF-β as a pro-tumorigenic factor in various types of cancer. This review will focus on recent findings regarding epithelial-mesenchymal transition (EMT) induced by TGF-β, in relation to crosstalk with some other signaling pathways, and the roles of TGF-β in lung and pancreatic cancers, in which TGF-β has been shown to be involved in cancer progression. Recent findings also strongly suggested that targeting TGF-β signaling using specific inhibitors may be useful for the treatment of some cancers. TGF-β plays a pivotal role in the differentiation and function of regulatory T cells (Tregs). TGF-β is produced as latent high molecular weight complexes, and the latent TGF-β complex expressed on the surface of Tregs contains glycoprotein A repetitions predominant (GARP, also known as leucine-rich repeat containing 32 or LRRC32). Inhibition of the TGF-β activities through regulation of the latent TGF-β complex activation will be discussed.

Distribución geográfica de la avifauna en la Sierra Madre Oriental de San Luis Potosí, México: un análisis regional de su estado de conservación / Geographic distribution of birds in the Sierra Madre Oriental of San Luis Potosí, México: a regional analysis of conservation status

The Sierra Madre Oriental region in the mexican state of San Luis Potosí is a relevant place for bird conservation at a country level. Therefore the main goal of this study was to analyze the geographic patterns of distribution and the conservation current state of the birds, to support the needs to expand the conservation areas in the future. Data was collected from various databases of zoological museums and collections, and field sampling methods conducted from January 2009 to May 2011. Potential distributions were modeled for 284 species using GARP software and then a map was developed to determine areas with favorable environmental characteristics for the distribution of species richness. Finally, the importance of conservation areas for the potential distribution of birds in the region was evaluated. A total of 359 species were recorded of which 71.4% are permanent residents, 19% are winter migrants and 4% are summer residents. From this total, 41 species were endemic, 47 were species at risk and 149 were neotropical migrants. The largest species richness correspond to oak forests, cloud forests, and tropical moist forests located at altitudes from 100m to 1 500m. Their potential distribution was concentrated towards the center and Southeast of the study area. Only 10% of areas with a high potential conservation was included in areas of priority for bird conservation (AICA) and just 3% of all potential areas were under some governmental category of protection. However, no conservation area has a management plan currently applied and monitored. The information generated is important for the development of management proposals for birds conservation in the region.

La región de la Sierra Madre Oriental (SMO) en el estado de San Luis Potosí en México es considerada un sitio de relevancia para la conservación de la avifauna a nivel nacional. Por lo anterior, el objetivo de este estudio fue analizar la distribución geográfica de las aves en la zona para identificar las áreas con mayor concentración de la riqueza y evaluar su estado actual de conservación para fundamentar la necesidad de incrementar la superficie dedicada a las áreas naturales protegidas en el futuro. Se recolectó información proveniente de diversas bases de datos de colecciones y museos, además de realizar trabajo de campo en el periodo de enero 2009 a Mayo 2011. Se modelaron las distribuciones potenciales para 284 especies con el programa GARP y se elaboró un mapa de consenso para determinar la ubicación espacial de las áreas con condiciones ambientales para soportar el mayor número de especies. Finalmente, se evaluó la representatividad de las zonas dedicadas a la conservación para las aves. Se registraron 357 especies, de las cuales el 71.4% son residentes permanentes, 19% son migratorias de invierno y 3.9% residentes de verano. Del total, 41 especies son endémicas y 48 se encuentran en alguna categoría de riesgo; la mayor concentración de especies se presentó en las coberturas de bosques de encino, bosques mesófilos y selvas medianas y bajas caducifolias, en un intervalo altitudinal entre 100-1 500m con una más alta cantidad de nichos en la parte centro y hacia el sur y este de la región. Sólo el 10% de las zonas con alto potencial de número de especies está incluido como área de importancia para la conservación de las aves y el 3% del total de áreas potenciales está bajo alguna categoría estatal de protección; sin embargo, ninguna de las áreas tiene un plan de manejo que esté siendo aplicado y monitoreado. La información generada es importante para el desarrollo de propuestas de conservación para las aves en la región.

Regionalización biogeográfica de la mastofauna de los bosques tropicales perennifolios de Mesoamérica / Biogeographic regionalization of the mammals of tropical evergreen forests in Mesoamerica

Mesoamerica is a biologically complex zone that expands from Southern Mexico to extreme Northern Colombia. The biogeographical patterns and relationships of the mammalian fauna associated to the Mesoamerican Tropical Evergreen Forest (MTEF) are poorly understood, in spite of the wide distribution of this kind of habitat in the region. We compiled a complete georeferenced database of mammalian species distributed in the MTEF of specimens from museum collections and scientific literature. This database was used to create potential distribution maps through the use of environmental niche models (ENMs) by using the Genetic Algorithm for Rule-Set Production (GARP) using 22 climatic and topographic layers. Each map was used as a representation of the geographic distribution of the species and all available maps were summed to obtain general patterns of species richness in the region. Also, the maps were used to construct a presence-absence matrix in a grid of squares of 0.5 degrees of side, that was analyzed in a Parsimony Analysis of Endemicity (PAE), which resulted in a hypothesis of the biogeographic scheme in the region. We compiled a total of 41 527 records of 233 species of mammals associated to the MTEF. The maximum concentration of species richness (104-138 species) is located in the areas around the isthmus of Tehuantepec, Northeastern Chiapas-Western Guatemala, Western Honduras, Central Nicaragua to Northwestern Costa Rica and Western Panama. The proposed regionalization indicates that mammalian faunas associated to these forests are composed of two main groups that are divided by the isthmus of Tehuantepec in Oaxaca in: a) a Northern group that includes Sierra Madre of Chiapas-Guatemala and Yucatan Peninsula; and b) an austral group, that contains the Pacific slope of Chiapas towards the South including Central America. Some individual phylogenetic studies of mammal species in the region support the relationships between the areas of endemism proposed, which suggest a common biogeographical history. in spite that Mesoamerica is considered one of the most important hotspots for biological conservation, the poor knowledge of the biogeographic patterns, the scarcity of protected areas, and the high rate of habitat transformation due to human activities, make prioritary the development of conservation strategies that include patterns of species richness, endemism, and mammalian associations.

Este trabajo presenta una propuesta de regionalización biogeográfica de los bosques tropicales perennifolios de Mesoamérica, resultado de un análisis de parsimonia de endemismos (PAE), utilizando modelos de nicho ecológico (GARP) con mamíferos terrestres, usando 41 527 registros para las 233 especies de mamíferos reconocidas. La regionalización propuesta muestra que los bosques tropicales perennifolios de Mesoamérica se dividen por el istmo de Tehuantepec en Oaxaca en: a) un grupo septentrional que comprende la Sierra Madre de Chiapas-Guatemala y la Península de Yucatán, y b) un grupo austral, que contiene la vertiente pacífica hacia el sur incluyendo Centroamérica. Además se encontró congruencia con trabajos filogenéticos, lo que sugiere una historia biogeográfica común.

Predictive distribution modeling for rare Himalayan medicinal plant Berberis aristata DC.

Predictive distribution modelling of Berberis aristata DC, a rare threatened plant with high medicinal values has been done with an aim to understand its potential distribution zones in Indian Himalayan region. Bioclimatic and topographic variables were used to develop the distribution model with the help of three different algorithms viz. Genetic Algorithm for Rule-set Production (GARP), Bioclim and Maximum entropy (MaxEnt). Maximum entropy has predicted wider potential distribution (10.36%) compared to GARP (4.63%) and Bioclim (2.44%). Validation confirms that these outputs are comparable to the present distribution pattern of the B. aristata. This exercise highlights that this species favours Western Himalaya. However, GARP and MaxEnt’s prediction of Eastern Himalayan states (i.e. Arunachal Pradesh, Nagaland and Manipur) are also identified as potential occurrence places require further exploration.

Brazilian Atlantic Forest lato sensu: the most ancient Brazilian forest, and a biodiversity hotspot, is highly threatened by climate change

After 500 years of exploitation and destruction, the Brazilian Atlantic Forest has been reduced to less the 8% of its original cover, and climate change may pose a new threat to the remnants of this biodiversity hotspot. In this study we used modelling techniques to determine present and future geographical distribution of 38 species of trees that are typical of the Brazilian Atlantic Forest (Mata Atlântica), considering two global warming scenarios. The optimistic scenario, based in a 0.5% increase in the concentration of CO2 in the atmosphere, predicts an increase of up to 2 °C in the Earth's average temperature; in the pessimistic scenario, based on a 1% increase in the concentration of CO2 in the atmosphere, temperature increase may reach 4 °C. Using these parameters, the occurrence points of the studied species registered in literature, the Genetic Algorithm for Rule-set Predictions/GARP and Maximum entropy modeling of species geographic distributions/MaxEnt we developed models of present and future possible occurrence of each species, considering Earth's mean temperature by 2050 with the optimistic and the pessimistic scenarios of CO2 emission. The results obtained show an alarming reduction in the area of possible occurrence of the species studied, as well as a shift towards southern areas of Brazil. Using GARP, on average, in the optimistic scenario this reduction is of 25% while in the pessimistic scenario it reaches 50%, and the species that will suffer the worst reduction in their possible area of occurrence are: Euterpe edulis, Mollinedia schottiana, Virola bicuhyba, Inga sessilis and Vochysia magnifica. Using MaxEnt, on average, in the optimistic scenario the reduction will be of 20% while in the pessimistic scenario it reaches 30%, and the species that will suffer the worst reduction are: Hyeronima alchorneoides, Schefflera angustissima, Andira fraxinifolia and the species of Myrtaceae studied.

Nos últimos 500 anos de ocupação da costa brasileira, de um total de 1.300.000 km², apenas cerca de 8% da cobertura original da Mata Atlântica foi preservada. Os poucos fragmentos restantes dessa devastação apresentam diversos tamanhos, formas, estádios de sucessão e situação de conservação. Cerca de metade dos remanescentes florestais de grande extensão estão protegidos na forma de Unidades de Conservação. A maioria desses fragmentos se encontra hoje nas regiões serranas, principalmente a fachada da Serra do Mar, por serem impróprias para práticas agrícolas. Neste estudo, usamos técnicas de modelagem para determinar a distribuição geográfica presente e futura de 38 espécies arbóreas típicas da Mata Atlântica lato sensu, considerando dois cenários de aquecimento global. O cenário otimista prevê uma taxa anual de 0,5% de aumento na concentração de CO2 na atmosfera e um aumento médio da temperatura inferior a 2 °C. O cenário pessimista prevê uma taxa anual de 1,0% de aumento na concentração de CO2 na atmosfera e um aumento médio da temperatura superior a 3 °C. Usando estes parâmetros, os pontos de ocorrência atual das espécies e o algoritmo genético para previsões baseadas em regras pré-estabelecidas (GARP), desenvolvemos modelos da distribuição futura das espécies estudadas, considerando as temperaturas projetadas para 2050. Os resultados obtidos mostraram uma alarmante redução na área que as espécies estudadas poderão ocupar, bem como um deslocamento da ocorrência atual em direção ao sul do Brasil. Na média, com o cenário otimista, a redução da área potencial de ocorrência é de 25%, enquanto que no cenário pessimista este patamar é da ordem de 50%. As espécies que sofrerão a maior redução na área de ocorrência são: Euterpe edulis, Mollinedia schottiana, Virola bicuhyba, Inga sessilis e Vochysia magnifica.

How many studies are necessary to compare niche-based models for geographic distributions? Inductive reasoning may fail at the end / Quantos estudos ainda serão necessários para avaliar modelos de distribuição geográfica baseados em modelagem do nicho? Um pensamento indutivo pode estar fadado ao fracasso

The use of ecological niche models (ENM) to generate potential geographic distributions of species has rapidly increased in ecology, conservation and evolutionary biology. Many methods are available and the most used are Maximum Entropy Method (MAXENT) and the Genetic Algorithm for Rule Set Production (GARP). Recent studies have shown that MAXENT perform better than GARP. Here we used the statistics methods of ROC - AUC (area under the Receiver Operating Characteristics curve) and bootstrap to evaluate the performance of GARP and MAXENT in generate potential distribution models for 39 species of New World coral snakes. We found that values of AUC for GARP ranged from 0.923 to 0.999, whereas those for MAXENT ranged from 0.877 to 0.999. On the whole, the differences in AUC were very small, but for 10 species GARP outperformed MAXENT. Means and standard deviations for 100 bootstrapped samples with sample sizes ranging from 3 to 30 species did not show any trends towards deviations from a zero difference in AUC values of GARP minus AUC values of MAXENT. Ours results suggest that further studies are still necessary to establish under which circumstances the statistical performance of the methods vary. However, it is also important to consider the possibility that this empirical inductive reasoning may fail in the end, because we almost certainly could not establish all potential scenarios generating variation in the relative performance of models.

A utilização de modelos de nicho ecológico (ENM) para gerar distribuições geográficas potenciais de espécies tem aumentado rapidamente nas áreas de ecologia, biologia da conservação e biologia evolutiva. O Método de Máxima Entropia (MAXENT) e o Algoritmo Genético para Produção de Conjunto de Regras (GARP) estão entre os métodos mais utilizados, e estudos recentes têm atribuído ao MAXENT um melhor desempenho no processo de modelagem com relação ao GARP. Neste trabalho, foram utilizados os métodos estatísticos ROC - AUC (area under the Receiver Operating Characteristics curve) e de reamostragem (bootstrap) para avaliar o desempenho do GARP e MAXENT em gerar modelos de distribuição potencial para 39 espécies de cobras corais do Novo Mundo. Os resultados mostraram que os valores de AUC para o GARP variaram de 0,923 a 0,999, enquanto que para o MAXENT variaram de 0,877 a 0,999. Em geral, as diferenças de AUC entre os dois métodos foram pequenas, embora o GARP tenha apresentado melhor desempenho que o MAXENT para 10 espécies. Valores de média e desvio padrão de 100 amostras variando de 3 a 30 espécies não revelaram qualquer tendência de desvio em relação à diferença zero entre valores de AUC do GARP menos valores de AUC do MAXENT. Estes resultados sugerem que mais estudos serão necessários para determinar sob quais circunstâncias o desempenho estatístico dos modelos varia, embora seja importante considerar também a possibilidade de que argumentações empírico-indutivas em favor de um ou outro método podem falhar, já que é quase impossível estabelecer todos os cenários potenciais causadores de variação no desempenho dos modelos.

Ecological niche modelling and differentiation between Rhodnius neglectus Lent, 1954 and Rhodnius nasutus Stål, 1859 (Hemiptera: Reduviidae: Triatominae) in Brazil

Ecological niche modelling was used to predict the potential geographical distribution of Rhodnius nasutus Stål and Rhodnius neglectus Lent, in Brazil and to investigate the niche divergence between these morphologically similar triatomine species. The distribution of R. neglectus covered mainly the cerrado of Central Brazil, but the prediction maps also revealed its occurrence in transitional areas within the caatinga, Pantanal and Amazon biomes. The potential distribution of R. nasutus covered the Northeastern Region of Brazil in the semi-arid caatinga and the Maranhão babaçu forests. Clear ecological niche differences between these species were observed. R. nasutus occurred more in warmer and drier areas than R. neglectus. In the principal component analysis PC1 was correlated with altitude and temperature (mainly temperature in the coldest and driest months) and PC2 with vegetation index and precipitation. The prediction maps support potential areas of co-occurrence for these species in the Maranhão babaçu forests and in caatinga/cerrado transitional areas, mainly in state of Piaui. Entomologists engaged in Chagas disease vector surveillance should be aware that R. neglectus and R. nasutus can occur in the same localities of Northeastern Brazil. Thus, the identification of bugs in these areas should be improved by applying morphometrical and/or molecular methods.

An ecoregional classification for the state of Roraima, Brazil: the importance of landscape in malaria biology

Understanding the different background landscapes in which malaria transmission occurs is fundamental to understanding malaria epidemiology and to designing effective local malaria control programs. Geology, geomorphology, vegetation, climate, land use, and anopheline distribution were used as a basis for an ecological classification of the state of Roraima, Brazil, in the northern Amazon Basin, focused on the natural history of malaria and transmission. We used unsupervised maximum likelihood classification, principal components analysis, and weighted overlay with equal contribution analyses to fine-scale thematic maps that resulted in clustered regions. We used ecological niche modeling techniques to develop a fine-scale picture of malaria vector distributions in the state. Eight ecoregions were identified and malaria-related aspects are discussed based on this classification, including 5 types of dense tropical rain forest and 3 types of savannah. Ecoregions formed by dense tropical rain forest were named as montane (ecoregion I), submontane (II), plateau (III), lowland (IV), and alluvial (V). Ecoregions formed by savannah were divided into steppe (VI, campos de Roraima), savannah (VII, cerrado), and wetland (VIII, campinarana). Such ecoregional mappings are important tools in integrated malaria control programs that aim to identify specific characteristics of malaria transmission, classify transmission risk, and define priority areas and appropriate interventions. For some areas, extension of these approaches to still-finer resolutions will provide an improved picture of malaria transmission patterns.