128 research outputs found
Etude de la répartition du grillon des bois Nemobius sylvestris (Rosc) dans un habitat naturel — I. les larves
The spatial distribution of a larval population of wood- crickets (Nemobius sylvestris) has been studied into two obser vation quadrats, located close to the edges of an oak wood near Toulouse (fig. 1). In both study areas, population density varied seasonally, with peak numbers during summer and autumn, depending upon climatic conditions. Whereas larval distribution was clumped all the year round in quadrat A located near the E-W edge of the wood, the situation was different in quadrat B located near the NNe-SSw border of the same wood. The observed difference in larval distribution pattern between the two quadrats can be explained by the effect of forest border orientation upon the aggregation of wood-cricket larvae. At any time of the year, their numbers increased progressively, from the edge of the wood to 15 metres inside, in quadrat A. The situation was different in quadrat B, except in winter time. Larval distribution was also influenced by the proximity of trees. In quadrat A, the wood-cricket larvae were more numerous close to the base of the trees. This also occured in quadrat B, but only during the summer and the autumn. The various factors influencing the spatial distribution of Nemobius sylvestris larvae can act synergically or antagonistically, according to local conditions. However the proximity of a forest border and its orientation appear to play the major roles
Etude de la répartition du Grillon des Bois Nemobius sylvestris (Bosc) dans un habitat naturel - II. Les adultes
Adult populations of Nemobius sylvestris were studied in the same two quadrats used for the study of the distribution patterns of their larval populations (Morvan, Campan and Thon, 1977). Adult wood-crickets were not found above ground in winter or even spring time in the Toulouse region. Their population increase in summer was apparently due to the imaginai molt of a new cohort in late spring
Arqueología de rescate en Piedra del Águila, Neuquén: sitio Cueva del Choique
The information obtained from the excavation of the Cueva del Choique site, in the north side of the Limay river, Neuquén Province, is reported here. The activities we present were carried out in the context of an Archaeological Rescue project designated to diminish the impact generated by the construction of the dam "Pichi Picún Leufú". These evidences are interpreted in the context of the information available on a regional scale, exploring tendencies related to different issues. Among others, archaeofaunistic remains and technological strategies. Finally, we present an evaluation of the intensity of past human activity in the site and in this area.En este trabajo se presenta información obtenida a partir de excavaciones de rescate realizadas en el sitio Cueva del Choique ubicado en la margen norte del río Limay, provincia de Neuquén. Estas actividades se desarrollaron en el marco de un proyecto de rescate arqueológico motivado por la construcción de la represa hidroeléctrica "Pichi Picún Leufú ". En una segunda instancia de análisis, estas evidencias son interpretadas en el marco de la información disponible para la región, explorando algunas tendencias existentes a nivel arqueofaunístico y tecnológico. Por último, se presenta una estimación general de la intensidad de uso humano de este sitio y de la región.Sociedad Argentina de Antropologí
Arqueología de rescate en Piedra del Águila, Neuquén: sitio Cueva del Choique
The information obtained from the excavation of the Cueva del Choique site, in the north side of the Limay river, Neuquén Province, is reported here. The activities we present were carried out in the context of an Archaeological Rescue project designated to diminish the impact generated by the construction of the dam "Pichi Picún Leufú". These evidences are interpreted in the context of the information available on a regional scale, exploring tendencies related to different issues. Among others, archaeofaunistic remains and technological strategies. Finally, we present an evaluation of the intensity of past human activity in the site and in this area.En este trabajo se presenta información obtenida a partir de excavaciones de rescate realizadas en el sitio Cueva del Choique ubicado en la margen norte del río Limay, provincia de Neuquén. Estas actividades se desarrollaron en el marco de un proyecto de rescate arqueológico motivado por la construcción de la represa hidroeléctrica "Pichi Picún Leufú ". En una segunda instancia de análisis, estas evidencias son interpretadas en el marco de la información disponible para la región, explorando algunas tendencias existentes a nivel arqueofaunístico y tecnológico. Por último, se presenta una estimación general de la intensidad de uso humano de este sitio y de la región.Sociedad Argentina de Antropologí
Le cerf
Synthèse des études disponibles sur le cerf en France (Génétique population, répartition, particularités morphologiques, particularités physiologiques, pathologie, utilisation de l'espace, utilisation du temps, alimentation, vie
sociale, comportement reproducteur, relations interspécifiques, dynamique et structure des populations
Promoter Sequences Prediction Using Relational Association Rule Mining
In this paper we are approaching, from a computational perspective, the problem of promoter sequences prediction, an important problem within the field of bioinformatics. As the conditions for a DNA sequence to function as a promoter are not known, machine learning based classification models are still developed to approach the problem of promoter identification in the DNA. We are proposing a classification model based on relational association rules mining. Relational association rules are a particular type of association rules and describe numerical orderings between attributes that commonly occur over a data set. Our classifier is based on the discovery of relational association rules for predicting if a DNA sequence contains or not a promoter region. An experimental evaluation of the proposed model and comparison with similar existing approaches is provided. The obtained results show that our classifier overperforms the existing techniques for identifying promoter sequences, confirming the potential of our proposal
DNA Methylation Changes in Atypical Adenomatous Hyperplasia, Adenocarcinoma In Situ, and Lung Adenocarcinoma
BACKGROUND:Aberrant DNA methylation is common in lung adenocarcinoma, but its timing in the phases of tumor development is largely unknown. Delineating when abnormal DNA methylation arises may provide insight into the natural history of lung adenocarcinoma and the role that DNA methylation alterations play in tumor formation. METHODOLOGY/PRINCIPAL FINDINGS:We used MethyLight, a sensitive real-time PCR-based quantitative method, to analyze DNA methylation levels at 15 CpG islands that are frequently methylated in lung adenocarcinoma and that we had flagged as potential markers for non-invasive detection. We also used two repeat probes as indicators of global DNA hypomethylation. We examined DNA methylation in 249 tissue samples from 93 subjects, spanning the putative spectrum of peripheral lung adenocarcinoma development: histologically normal adjacent non-tumor lung, atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS, formerly known as bronchioloalveolar carcinoma), and invasive lung adenocarcinoma. Comparison of DNA methylation levels between the lesion types suggests that DNA hypermethylation of distinct loci occurs at different time points during the development of lung adenocarcinoma. DNA methylation at CDKN2A ex2 and PTPRN2 is already significantly elevated in AAH, while CpG islands at 2C35, EYA4, HOXA1, HOXA11, NEUROD1, NEUROD2 and TMEFF2 are significantly hypermethylated in AIS. In contrast, hypermethylation at CDH13, CDX2, OPCML, RASSF1, SFRP1 and TWIST1 and global DNA hypomethylation appear to be present predominantly in invasive cancer. CONCLUSIONS/SIGNIFICANCE:The gradual increase in DNA methylation seen for numerous loci in progressively more transformed lesions supports the model in which AAH and AIS are sequential stages in the development of lung adenocarcinoma. The demarcation of DNA methylation changes characteristic for AAH, AIS and adenocarcinoma begins to lay out a possible roadmap for aberrant DNA methylation events in tumor development. In addition, it identifies which DNA methylation changes might be used as molecular markers for the detection of preinvasive lesions
Deep Sequencing of the Oral Microbiome Reveals Signatures of Periodontal Disease
The oral microbiome, the complex ecosystem of microbes inhabiting the human mouth, harbors several thousands of bacterial types. The proliferation of pathogenic bacteria within the mouth gives rise to periodontitis, an inflammatory disease known to also constitute a risk factor for cardiovascular disease. While much is known about individual species associated with pathogenesis, the system-level mechanisms underlying the transition from health to disease are still poorly understood. Through the sequencing of the 16S rRNA gene and of whole community DNA we provide a glimpse at the global genetic, metabolic, and ecological changes associated with periodontitis in 15 subgingival plaque samples, four from each of two periodontitis patients, and the remaining samples from three healthy individuals. We also demonstrate the power of whole-metagenome sequencing approaches in characterizing the genomes of key players in the oral microbiome, including an unculturable TM7 organism. We reveal the disease microbiome to be enriched in virulence factors, and adapted to a parasitic lifestyle that takes advantage of the disrupted host homeostasis. Furthermore, diseased samples share a common structure that was not found in completely healthy samples, suggesting that the disease state may occupy a narrow region within the space of possible configurations of the oral microbiome. Our pilot study demonstrates the power of high-throughput sequencing as a tool for understanding the role of the oral microbiome in periodontal disease. Despite a modest level of sequencing (∼2 lanes Illumina 76 bp PE) and high human DNA contamination (up to ∼90%) we were able to partially reconstruct several oral microbes and to preliminarily characterize some systems-level differences between the healthy and diseased oral microbiomes
Diets based on virgin olive oil or fish oil but not on sunflower oil prevent age-related alvolar bone resorption by mitochondrial-related mechanisms
Background/Objectives:
Aging enhances frequency of chronic diseases like cardiovascular diseases or periodontitis. Here we reproduced an age-dependent model of the periodontium, a fully physiological approach to periodontal conditions, to evaluate the impact of dietary fat type on gingival tissue of young (6 months old) and old (24 months old) rats.Methods/Findings:
Animals were fed life-long on diets based on monounsaturated fatty acids (MUFA) as virgin olive oil, n-6 polyunsaturated fatty acids (n-6PUFA), as sunflower oil, or n-3PUFA, as fish oil. Age-related alveolar bone loss was higher in n-6PUFA fed rats, probably as a consequence of the ablation of the cell capacity to adapt to aging. Gene expression analysis suggests that MUFA or n-3PUFA allowed mitochondria to maintain an adequate turnover through induction of biogenesis, autophagy and the antioxidant systems, and avoiding mitochondrial electron transport system alterations.Conclusions:
The main finding is that the enhanced alveolar bone loss associated to age may be targeted by an appropriate dietary treatment. The mechanisms involved in this phenomenon are related with an ablation of the cell capacity to adapt to aging. Thus, MUFA or n-3PUFA might allow mitochondrial maintaining turnover through biogenesis or autophagy. They might also be able to induce the corresponding antioxidant systems to counteract age-related oxidative stress, and do not inhibit mitochondrial electron transport chain. From the nutritional and clinical point of view, it is noteworthy that the potential treatments to attenuate alveolar bone loss (a feature of periodontal disease) associated to age could be similar to some of the proposed for the prevention and treatment of cardiovascular diseases, a group of pathologies recently associated with age-related periodontitis.This study was supported by I+D grants from the Spanish Ministry of Education and Science (AGL2008-01057) and the Autonomous
Government of Andalusia (AGR832)
- …