Fusariotoxins such as fumonisin B1 (FB1) and deoxynivalenol (DON) cause deleterious effects on the intestine of pigs. The aim of this study was to evaluate the effect of these mycotoxins, alone and in combination, on jejunal explants from piglets, using histological, immunohistochemical and ultrastructural assays. Five 24-day old pigs were used for sampling the explants. Forty-eight explants were sampled from each animal. Explants were incubated for 4 hours in culture medium and medium containing FB1 (100 µM), DON (10 µM) and both mycotoxins (100 µM FB1 plus 10 µM DON). Exposure to all treatments induced a significant decrease in the normal intestinal morphology and in the number of goblet cells, which were more severe in explants exposed to DON and both mycotoxins. A significant reduction in villus height occurred in groups treated with DON and with co-contamination. Expression of E-cadherin was significantly reduced in explants exposed to FB1 (40%), DON (93%) and FB1 plus DON (100%). The ultrastructural assay showed increased intercellular spaces and no junction complexes on enterocytes exposed to mycotoxins. The present data indicate that FB1 and DON induce changes in cell junction complexes that could contribute to increase paracellular permeability. The ex vivo model was adequate for assessing intestinal toxicity induced by exposure of isolated or associated concentrations of 100 µM of FB1 and 10 µM of DON.

Despite the increasing knowledge about the genetic alterations and molecular pathways involved in gliomas, few studies have investigated the association between the gene expression profiles (GEP) and both cytogenetics and histopathology of gliomas. Here, we analyzed the GEP (U133Plus2.0 chip) of 40 gliomas (35 astrocytic tumors, 3 oligodendrogliomas, and 2 mixed tumors) and their association with tumor cytogenetics and histopathology. Unsupervised and supervised analyses showed significantly different GEP in low- vs high-grade gliomas, the most discriminating genes including genes involved in the regulation of cell proliferation, apoptosis, DNA repair, and signal transduction. In turn, among glioblastoma multiforme (GBM), 3 subgroups of tumors were identified according to their GEP, which were closely associated with the cytogenetic profile of their ancestral tumor cell clones: (i) EGFR amplification, (ii) isolated trisomy 7, and (iii) more complex karyotypes. In summary, our results show a clear association between the GEP of gliomas and tumor histopathology; additionally, among grade IV astrocytoma, GEP are significantly associated with the cytogenetic profile of the ancestral tumor cell clone. Further studies in larger series of patients are necessary to confirm our observations.

Castanea sativa is susceptible to Phytophthora spp., a serious root pathogen causing ink disease, while C. crenata and C. mollissima show resistance to infection. Interspecific controlled crosses were established for introgression of resistance genes from the resistant species into the susceptible C. sativa, and two mapping populations were created. Phytophthora cinnamomi resistance of each progeny was evaluated by root and excised shoot inoculation tests. The number of days of survival after root inoculation was the best discriminator of resistance to P. cinnamomi while the percentage of shoots with internal lesions was the symptom most associated with survival. The lesion progression rate in the excised shoot inoculation test was strongly and negatively correlated with survival in the root inoculation test. The excised shoot inoculation test appears to be a reliable approach for screening the resistance of chestnut genotypes to P. cinnamomi. Strong genetic correlations were obtained between survival and ink disease symptoms and among symptoms, indicating that common or linked genes might influence resistance to P. cinnamomi. The most resistant genotypes selected from this study will be tested for other commercial variables, such as ease of vegetative propagation and stock-scion compatibility.

Arbutus unedo grows spontaneously around the Mediterranean basin. The species is tolerant to drought and has a strong regeneration capacity following fires making it interesting for Mediterranean forestation programs. Considering the sparse information about the potential of this fruit tree to be propagated in vitro, a project to clone selected trees based on their fruit production was initiated a few years ago. The role of several factors on A. unedo propagation was evaluated. The results showed that 8.9 μm kinetin gave the best results although not significantly different from those obtained with benzyladenine or zeatin. The inclusion of thidiazuron or 1-naphthaleneacetic acid promoted callus growth and had deleterious effects on the multiplication rate. The genotype of the donor plants is also a factor interfering with the multiplication. The results also indicated that the conditions used for multiplication influenced the behavior of shoots during the rooting phase.

Arbutus unedo L. is a species of strawberry tree, widely represented in the Mediterranean climates of southern Europe. Fruits are used to make jellies and a spirit called "medronheira." Shoot apices and nodal segments from epicormic and coppiced shoots of adult plants were used for plant propagation. Shoot apices from epicormic shoots, which were developed in a growth chamber, showed higher rates of in vitro establishment. The results also indicated that shoot apices are more effective for plant establishment than nodal segments, with rates of establishment significantly higher after 12 wk of culture. Of the three basal media used in combination with 9.0 µM benzyladenine and 0.087 M sucrose, the FS medium with the micronutrients of the Murashige and Skoog medium gave the highest rates of multiplication, especially when the parameter analyzed was the number of clusters formed. When shoot apices from selected adult plants (AL01-AL06) were tested, the multiplication rate was not significantly different among the plants. However, in the conditions tested, shoots from the clones AL1, AL2, and AL3 showed better development, whereas shoots from AL4, AL5, and AL6 showed an impaired development and could not be rooted. Rooting was achieved in all the conditions tested, even in the absence of auxin. The inclusion of an auxin significantly increased root formation, whereas the addition of charcoal did not improve root formation. Rooted plantlets were acclimatized, and some of them are now in the field for further study.

SummaryEucalyptus nitens Maiden (shining gum) is a frost-tolerant species of Eucalyptus that can be used as an alternative species to Eucalyptus globulus in some regions of Portugal where winter temperatures are too low. Seedlings and 1-yr-old shoot tips and nodes were used for micropropagation of E. nitens. The best multiplication rate (2.25) was obtained when seedling shoots (,15 mm) were cultured on a medium containing the major nutrients (at half-strength) and minor elements of Murashige and Skoog (1962) medium, the organics of De Fossard medium (De Fossard et al., 1974) and a combination of benzyladenine (0.9 mM ) and 1-naphthaleneacetic acid (0.05 mM ). Seedling cuttings (4-, 8-, and 10-wk-old) rooted well on media containing several concentrations of 3-indolebutyric acid (4.9, 9.8, and 14.8 mM ) or 3-indoleacetic acid (5.7, 11.4, and 17.1 mM ), giving frequencies of root induction above 80%. With this type of explant, root formation was also found on basal medium without growth regulators. Rooting of in vitro-propagated shoots obtained from seedlings (8-wk-old) after four subcultures (every 3 wk) was more difficult, with the best results obtained on a medium containing 14.7 mM 3-indolebutyric acid (60.0% root induction). No root formation was achieved when shoots from 1-yr-old explants were used. After a period of 4 mo., 96.3% of the plants transferred to the greenhouse survived acclimatization.

The behaviour of reinforced concrete beam‐column (RCBC) joints may have an important influence on the structural behaviour of unbraced framed structures—this explains why current technical specifications require accounting for their deformation. However, the available numerical models for RCBC joints are rather complex, so that, at the end of the day, these joints are commonly modeled using one of two alternative simplified models: the rigid joint model and the centerline joint model. This calls for the development of “Simplified Classification Criteria”, which are simplified procedures to assess the influence of RCBC joints on the structural behaviour, that is, to determine whether a simplified joint model can be employed in the numerical model of the overall structure without leading to major errors in the analysis. This paper focuses on the possibility of using the rigid joint model. As a starting point for the step‐by‐step development of general classification criteria for RCBC joints we employ the basic simplified classification criterion already existing for steel beam‐column joints.

Joints in steel rectangular hollow sections filled with concrete present the added difficulty of involving the deformability of the connected faces in bending. This implies that, unless a good estimate of the moment-rotation curve can be obtained, complex and expensive detailing is required to ensure a fairly rigid response of the joint. A first step to achieve the objective of predicting the behavior of such a joint corresponds to an assessment of the initial stiffness of the joint. Starting with a brief review of the current state-of-the-art in the behavior of joints in hollow sections, this paper presents and discusses an analytical model based on an equivalent strip of the loaded face. A simple solution based on this model that has been calibrated with numerical simulations is also derived. The main parameters considered are the thickness of the loaded face and the dimensions of the loading area. Comparisons with some available numerical and experimental results are quite encouraging.