Interferon-beta protects astrocytes against tumour necrosis factor-induced apoptosis via activation of p38 mitogen-activated protein kinase

Several large clinical trials have demonstrated that interferon-beta (IFN-beta) therapy is effective in the treatment of multiple sclerosis (MS) patients. However, the mechanisms underlying the beneficial effects of IFN-beta are not fully understood. Most of the effort in the study of the relevant mechanisms of IFN-beta has dealt with its immunomodulatory actions. However, the beneficial effects of IFN-beta in MS patients may also depend on non-immune mechanisms, including the modulation of astrocyte function. In the present work, we have found that IFN-beta treatment protects astrocytes against tumour necrosis factor-induced apoptosis via activation of p38 mitogen-activated protein kinase. We propose that this effect may be of importance to protect astrocytes against apoptosis within the demyelinated plaques of the MS.     

Effect of salmon melanin-concentrating hormone and mammalian gonadotrophin-releasing hormone on somatolactin release in pituitary culture of Cichlasoma dimerus

We detected a close morphological association between melanin-concentrating hormone (MCH)-immunoreactive (ir) fibers and somatolactin (SL)-ir cells in the pars intermedia of the cichlid fish Cichlasoma dimerus by double-label immunofluorescence. Male pituitaries obtained from adult C. dimerus were incubated with 0.1-10 muM salmon MCH, and the amount of SL released into the culture medium was semi-quantified by Western blot. This assay showed an increase of SL release in a dose-dependent manner (linear regression: P < 0.05). A close association of GnRH-ir fibers with SL-ir cells was also detected at the pars intermedia level. Male pituitaries were also incubated with 0.1-10 muM of mammalian GnRH, and SL release was semi-quantified by Western blot, showing an increase of released SL levels in a dose-dependent manner (linear regression: P < 0.05). In contrast, SL release was unaffected from female pituitaries incubated with salmon MCH; however, an increasing tendency was observed when mammalian GnRH was used. Hypothalamic close association of MCH-ir perikarya and GnRH-ir fibers was found by double-label immunofluorescence indicating a possible relationship between them. These results suggest that SL, like other pituitary hormones, is under hypothalamic control and is involved in diverse physiological processes including background adaptation and reproduction. This study has also shown that the in vitro culture of a single C. dimerus pituitary is a feasible method for studying the control of SL release and other pituitary hormones.     

Composition-driven Surface Domain Structuring Mediated by Sphingolipids and Membrane-active Proteins

Biomembranes contain a wide variety of lipids and proteins within an essentially two-dimensional structure. The coexistence of such a large number of molecular species causes local tensions that frequently relax into a phase or compositional immiscibility along the lateral and transverse planes of the interface. As a consequence, a substantial microheterogeneity of the surface topography develops and that depends not only on the lipid-protein composition, but also on the lateral and transverse tensions generated as a consequence of molecular interactions. The presence of proteins, and immiscibility among lipids, constitute major perturbing factors for the membrane sculpturing both in terms of its surface topography and dynamics. In this work, we will summarize some recent evidences for the involvement of membrane-associated, both extrinsic and amphitropic, proteins as well as membrane-active phosphohydrolytic enzymes and sphingolipids in driving lateral segregation of phase domains thus determining long-range surface topography.     

Fishpond dams affect leaf‐litter processing and associated detritivore communities along intermittent low‐order streams

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Phylogeny of the North American catfish family Ictaluridae (Teleostei: Siluriformes) combining morphology,genes and fossils

We performed the first combined‐data phylogenetic analysis of ictalurids including most living and fossil species. We sampled 56 extant species and 16 fossil species representing outgroups, the seven living genera, and the extinct genus ?Astephus long thought to be an ictalurid. In total, 209 morphological characters were curated and illustrated in MorphoBank from published and original work, and standardized using reductive coding. Molecular sequences harvested from GenBank for one nuclear and four mitochondrial genes were combined with the morphological data for total evidence analysis. Parsimony analysis recovers a crown clade Ictaluridae composed of seven living genera and numerous extinct species. The oldest ictalurid fossils are the Late Eocene members of Ameiurus and Ictalurus. The fossil clade ?Astephus placed outside of Ictaluridae and not as its sister taxon. Previous morphological phylogenetic studies of Ictaluridae hypothesized convergent evolution of troglobitic features among the subterranean species. In contrast, we found morphological evidence to support a single clade of the four troglobitic species, the sister taxon of all ictalurids. This result holds whether fossils are included or not. Some previously published clock‐based age estimates closely approximate our minimum ages of clades.