Phylobetadiversity among Forest Types in the Brazilian Atlantic Forest Complex

Phylobetadiversity is defined as the phylogenetic resemblance between communities or biomes. Analyzing phylobetadiversity patterns among different vegetation physiognomies within a single biome is crucial to understand the historical affinities between them. Based on the widely accepted idea that different forest physiognomies within the Southern Brazilian Atlantic Forest constitute different facies of a single biome, we hypothesize that more recent phylogenetic nodes should drive phylobetadiversity gradients between the different forest types within the Atlantic Forest, as the phylogenetic divergence among those forest types is biogeographically recent. We compiled information from 206 checklists describing the occurrence of shrub/tree species across three different forest physiognomies within the Southern Brazilian Atlantic Forest (Dense, Mixed and Seasonal forests). We analyzed intra-site phylogenetic structure (phylogenetic diversity, net relatedness index and nearest taxon index) and phylobetadiversity between plots located at different forest types, using five different methods differing in sensitivity to either basal or terminal nodes (phylogenetic fuzzy weighting, COMDIST, COMDISTNT, UniFrac and Rao’s H). Mixed forests showed higher phylogenetic diversity and overdispersion than the other forest types. Furthermore, all forest types differed from each other in relation phylobetadiversity patterns, particularly when phylobetadiversity methods more sensitive to terminal nodes were employed. Mixed forests tended to show higher phylogenetic differentiation to Dense and Seasonal forests than these latter from each other. The higher phylogenetic diversity and phylobetadiversity levels found in Mixed forests when compared to the others likely result from the biogeographical origin of several taxa occurring in these forests. On one hand, Mixed forests shelter several temperate taxa, like the conifers Araucaria and Podocarpus. On the other hand, tropical groups, like Myrtaceae, are also very representative of this forest type. We point out to the need of more attention to Mixed forests as a conservation target within the Brazilian Atlantic Forest given their high phylogenetic uniqueness.     

Unequal meiotic crossover: a frequent cause of NF1 microdeletions

Neurofibromatosis type 1 is a common autosomal dominant disorder caused by mutations of the NF1 gene on chromosome 17. In only 5%-10% of cases, a microdeletion including the NF1 gene is found. We analyzed a set of polymorphic dinucleotide-repeat markers flanking the microdeletion on chromosome 17 in a group of seven unrelated families with a de novo NF1 microdeletion. Six of seven microdeletions were of maternal origin. The breakpoints of the microdeletions of maternal origin were localized in flanking paralogous sequences, called "NF1-REPs." The single deletion of paternal origin was shorter, and no crossover occurred on the paternal chromosome 17 during transmission. Five of the six cases of maternal origin were informative, and all five showed a crossover, between the flanking markers, after maternal transmission. The observed crossovers flanking the NF1 region suggest that these NF1 microdeletions result from an unequal crossover in maternal meiosis I, mediated by a misalignment of the flanking NF1-REPs.     

Estrogen-mediated up-regulation of the Ca-dependent constitutive nitric oxide synthase in the rat aorta and heart

The role of endogenous estrogens has been studied in the regulation of the Ca-dependent constitutive nitric oxide synthase (cNOS) enzyme activity in aortic and cardiac tissues of the rat. The activity of cNOS enzyme was measured by the citrulline assay in the abdominal aorta and in the left ventricle of the heart obtained from male, sham-operated female and ovariectomized female Wistar rats. Estrogen replacement therapy (17-beta-estradiol, 20-100 microg/kg/day, s.c.) has been performed in ovariectomized rats over two weeks. We found that cNOS activity was higher in the aorta and heart of female rats compared to males. Ovariectomy decreased cNOS activity in both tissues to that level what could be observed in males. Estrogen supplementation caused a dose-dependent elevation of cNOS enzyme activity in cardiac and aortic tissues, where the higher dose (100 microg) completely restored cNOS enzyme activity to the levels found in females. We concluded that endogenous estrogens up-regulate the activity of the cNOS isoenzymes in the rat aorta and heart.     

Ophiostomatoid fungi including two new fungal species associated with pine root-feeding beetles in northern Spain

Many bark beetles live in a symbiosis with ophiostomatoid fungi but very little is known regarding these fungi in Spain. In this study, we considered the fungi associated with nine bark beetle species and one weevil infesting two native tree species (Pinus sylvestris and Pinus nigra) and one non-native (Pinus radiata) in Cantabria (Northern Spain). This included examination of 239 bark beetles or their galleries. Isolations yielded a total of 110 cultures that included 11 fungal species (five species of Leptographium sensu lato including Leptographium absconditum sp. nov., five species of Ophiostoma sensu lato including Ophiostoma cantabriense sp. nov, and one species of Graphilbum). The most commonly encountered fungal associates of the bark beetles were Grosmannia olivacea, Leptographium procerum, and Ophiostoma canum. The aggressiveness of the collected fungal species was evaluated using inoculations on two-year-old P. radiata seedlings. Leptographium wingfieldii, Leptographium guttulatum, and Ophiostoma ips were the only species capable of causing significant lesions.     

Autofluorescence and Ultrastructure in the Myxomycete Diachea leucopodia (Physarales)

Autofluorescence is reported for the first time in Myxomycete fruiting bodies. Ultrastructure of stalked sporangia of Diachea leucopodia (Didymiaceae, Physarales) was studied using scanning and transmission electron microscopy, energy-dispersive X-ray microanalysis, and fluorescence microscopy. External and internal properties of the peridium that surround the spores and capillitium exhibit autofluorescence. The stalk is composed of calcareous granules and energy-dispersive X-ray microanalysis demonstrates that the elemental composition of the peridium, capillitium, and stalk has varying concentrations of calcium.     

Synthesis and biological activity of benzo-fused 7-deazaadenosine analogues. 5- and 6-substituted 4-amino- or 4-alkylpyrimido[4,5-b]indole ribonucleosides

Two series of new 4-aminopyrimido[4,5-b]indole ribonucleosides bearing phenyl or hetaryl group at position 5 or 6 have been prepared by Suzuki or Stille cross-coupling reactions employing X-Phos ligand with (het)arylboronic acids or stannanes. A series of 4-substituted nucleosides has been also prepared by Pd-catalyzed cross-couplings or nucleophilic substitution. Some of these compounds displayed moderate antiviral activities against HCV and dengue viruses.     

A new species of Borgatomelissa Patiny, 2000 from eastern Morocco: Borgatomelissa flavimaura n. sp. (Hymenoptera,Andrenidae)

Until now, two species of Borgatomelissa Patiny, 2000 have been described, both from loci typici located in the Near East and eastern Africa. Borgatomelissa brevipennis (Walker, 1871), the most widespread taxon, has also been found in the southern Sahelo-Sudanian belt of the Sahara. A third species from eastern Morocco is described in the present study: Borgatomelissa flavimaura n. sp. In addition to taxonomic insights, the new species sheds a new light on the biogeography of the genus.     

Cyanobacteria-containing biofilms from a Mayan monument in Palenque,Mexico

Surfaces of buildings at the archaeological site of Palenque, Mexico, are colonized by cyanobacteria that form biofilms, which in turn cause aesthetic and structural damage. The structural characterization and species composition of biofilms from the walls of one of these buildings, El Palacio, are reported. The distribution of photosynthetic microorganisms in the biofilms, their relationship with the colonized substratum, and the three-dimensional structure of the biofilms were studied by image analysis. The differences between local seasonal microenvironments at the Palenque site, the bioreceptivity of stone and the relationship between biofilms and their substrata are described. The implications for the development and permanence of species capable of withstanding temporal heterogeneity in and on El Palacio, mainly due to alternating wet and dry seasons, are discussed. Knowledge on how different biofilms contribute to biodegradation or bioprotection of the substratum can be used to develop maintenance and conservation protocols for cultural heritage.     

Update on the challenging role of biofilms in peritoneal dialysis

Biofilms are commonly associated with an increased risk of patient infection. In peritoneal dialysis (PD), catheter associated infection, especially peritonitis, remains a clinically relevant problem. Although the presence of a biofilm is recognized in relapsing, repeat, and catheter-related peritonitis, it remains poorly characterized. In this review, an update on the role of biofilms in PD infections is presented. The emerging concept that host cells and tissue associated biofilms, in addition to the biofilms on the catheters themselves, contribute to the recalcitrance of infections is discussed. Furthermore, the evidence of biofilms on PD catheters, their developmental stages, and the possible influence of the PD environment are reviewed. The focus is given to ex vivo and in vitro studies that contribute to the elucidation of the interplay between host, microbial, and dialysis factors. The key issues that are still to be answered and the challenges to clinical practice are discussed.