2,282 research outputs found
Olive tree Galega cultivar acessions' identification based on RAPD markers
Olea europaea ssp. europaea (Oleaceae) grows in the Mediterranean region. The fruits are
used for olive oil and for fruit canning, besides the species is drought and salt tolerant. The
Galega cultivar represents 80% of the Portuguese olive area, and it is used in four out of the
five Protected Origin Denomination (POD) regions. Despite the large distribution area in the
country, cultivar certification is done through phenotypic characteristics, but environmental
influence might blur informativeness, and molecular markers could help in clarifying cultivar
accessions certification
III Encontro de Sistemas de Informação Geográfica. Aplicações SIG em Recursos Agro-Florestais e Ambientais
A publicação contém os resumos das comunicações e dos pósteres apresentados no III Encontro de Sistemas de Informação Geográfica
IV Encontro de Sistemas de Informação Geográfica : Aplicações SIG em Recursos Agro-Florestais e Ambientais : livro de resumos
Esta publicação reúne os resumos das comunicações apresentadas no IV Encontro de Sistemas de Informação
Geográfica, sob a forma de comunicações orais e pósteres e inclui, ainda, o programa científico do encontro
DNA markers to study genetic diversity and fingerprinting in Arbutus unedo L. (strawberry tree)
Strawberry tree (Ericaceae) is a species of Mediterranean climates growing in several
countries of the Mediterranean basin as well as in Portugal and Ireland. The edible fruits have
been used in different ways yet the production of a popular spirit is still the main application.
The species is also interesting from an ecological perspective since it is drought tolerant and
fire resistant. In spite of its large distribution in Portugal little is known about the genetic
diversity of the species and no efforts have been carried out to select the most interesting
trees. Material from selected trees (based on fruit production) in a total of 27 was collected all
around the country covering the distribution area of the species. In order to find out DNA
markers to characterise genetic diversity and to fingerprint Arbutus unedo, random amplified
polymorphic DNA (RAPD) and microsatellite markers (SSR) were used.
The set of 20 RAPD primers used generated 124 bands, from which 71 (57.3%) were
polymorphic and the expected heterozygosity was 0.27±0.014. The cluster analysis
(UPGMA) based on the Jaccard similarity index showed a similarity of 71% among the trees
of different origins. Only four genotypes could be grouped according to their geographical
distribution.
Eleven SSR primers designed for Vaccinium (an Ericaceae as A. unedo) were selected
according to their polymorphism, number of alleles per locus, cross-amplification, allele
scoring quality and the repeat motif, and were tested in A. unedo. Six loci showed to be
polymorphic, with 71% mean expected diversity, 10.5 mean number of alleles, and 67% of
average polymorphic information content. A mean homozygote excess was found (11%)
although not significant. Estimation of null allele frequency was about 9% on average. The
linkage disequilibrium test showed that all the loci were independent. The UPGMA
clustering based on the Lynch and Ritland coefficient showed that only two genotypes shared
about 50% of the alleles, but without a consistent geographic pattern, similarly to the results
obtained by RAPD analysis. The Mantel test confirmed that there is no correlation between
the genetic and the geographical distance matrices, for both makers. Reduced gene flow, due
to fragmentary distribution, together with the type of mating system of this species
(pollination by small insects), are plausible explanations for these results. As far as we know
our work is the first detailed study to evaluate A. unedo diversity by molecular markers
opening new perspectives for fingerprinting analysis and for conservation and improvement
purposes
Massive lower gastrointestinal bleeding from idiopathic ileocolonic varix: report of a case
Dis Colon Rectum. 2006 Apr;49(4):524-6.
Massive lower gastrointestinal bleeding from idiopathic ileocolonic varix: report of a case.
Lopes LM, Ramada JM, Certo MG, Pereira PR, Soares JM, Ribeiro M, Areias J, Pinho C.
SourceGastroenterology Department, Hospital Geral Santo António, Porto, Portugal. [email protected]
Abstract
Idiopathic varices of the entire colon are very rare. We report on a 64-year-old patient with massive lower gastrointestinal hemorrhage from an extensive ileocolonic varix. Diagnosis was established by colonoscopy. The patient underwent an emergency ileocolectomy with satisfactory results. This rare case shows the importance of colonoscopy in the evaluation of patients with lower gastrointestinal hemorrhage and reminds us that sometimes the diagnosis is not what we expect. Recognition of this abnormality is important because varices may be the cause of massive lower gastrointestinal hemorrhage.
PMID: 16395635 [PubMed - indexed for MEDLINE
In silico mechano-chemical model of bone healing for the regeneration of critical defects: The effect of BMP-2
The healing of bone defects is a challenge for both tissue engineering and modern ortho- paedics. This problem has been addressed through the study of scaffold constructs com- bined with mechanoregulatory theories, disregarding the influence of chemical factors and their respective delivery devices. Of the chemical factors involved in the bone healing pro- cess, bone morphogenetic protein-2 (BMP-2) has been identified as one of the most power- ful osteoinductive proteins. The aim of this work is to develop and validate a mechano- chemical regulatory model to study the effect of BMP-2 on the healing of large bone defects in silico. We first collected a range of quantitative experimental data from the literature con- cerning the effects of BMP-2 on cellular activity, specifically proliferation, migration, differen- tiation, maturation and extracellular matrix production. These data were then used to define a model governed by mechano-chemical stimuli to simulate the healing of large bone de- fects under the following conditions: natural healing, an empty hydrogel implanted in the de- fect and a hydrogel soaked with BMP-2 implanted in the defect. For the latter condition, successful defect healing was predicted, in agreement with previous in vivo experiments. Further in vivo comparisons showed the potential of the model, which accurately predicted bone tissue formation during healing, bone tissue distribution across the defect and the quantity of bone inside the defect. The proposed mechano-chemical model also estimated the effect of BMP-2 on cells and the evolution of healing in large bone defects. This novel in silico tool provides valuable insight for bone tissue regeneration strategies
Computational model of mesenchymal migration in 3D under chemotaxis
Cell chemotaxis is an important characteristic of cellular migration, which takes part in crucial aspects of life and development. In this work, we propose a novel in silico model of mesenchymal 3D migration with competing protrusions under a chemotactic gradient. Based on recent experimental observations, we identify three main stages that can regulate mesenchymal chemotaxis: chemosensing, dendritic protrusion dynamics and cell–matrix interactions. Therefore, each of these features is considered as a different module of the main regulatory computational algorithm. The numerical model was particularized for the case of fibroblast chemotaxis under a PDGF-bb gradient. Fibroblasts migration was simulated embedded in two different 3D matrices – collagen and fibrin – and under several PDGF-bb concentrations. Validation of the model results was provided through qualitative and quantitative comparison with in vitro studies. Our numerical predictions of cell trajectories and speeds were within the measured in vitro ranges in both collagen and fibrin matrices. Although in fibrin, the migration speed of fibroblasts is very low, because fibrin is a stiffer and more entangling matrix. Testing PDGF-bb concentrations, we noticed that an increment of this factor produces a speed increment. At 1 ng mL-1 a speed peak is reached after which the migration speed diminishes again. Moreover, we observed that fibrin exerts a dampening behavior on migration, significantly affecting the migration efficiency
- …