Differentiation and adaptive radiation of amphibious gobies (Gobiidae: Oxudercinae) in semi-terrestrial habitats

During several surveys made in the region of the lower Fly River and delta, Papua New Guinea, nine species of oxudercine gobies (Gobiidae: Oxudercinae) were recorded: Boleophthalmus caeruleomaculatus, Oxuderces wirzi, Periophthalmodon freycineti, Periophthalmus darwini, Periophthalmus novaeguineaensis, Periophthalmus takita, Periophthalmus weberi, Scartelaos histophorus and Zappa confluentus. An exploratory multivariate analysis of their habitat conditions discriminated five guilds, differentially distributed in habitats with different quantities of environmental water and three guilds corresponding to different levels of salinity. A partial correspondence between phylogenetic and ecological categories suggested the presence of parallel adaptive radiations within different genera. In particular, the species found in the most terrestrial habitats (P. weberi) was also found in the widest range of conditions, suggesting that colonization of extreme semi-terrestrial and freshwater habitats by this species was facilitated by eurytypy. It is proposed that these findings provide insight into convergent adaptations for the vertebrate eco-evolutionary transition from sea to land.     

Assessing coral bleaching and recovery with a colour reference card in Watamu Marine Park,Kenya

With this study we estimated the changes in colour, bleaching and mortality of coral colonies from February to December 2007, using the colour reference card method. The study was developed in the Watamu Marine Park lagoon (Kenya), bridging the local summer when seawater temperatures were highest and coral bleaching risk was at its maximum. Seven coral genera were selected, and their colour recorded using a colour reference card (Coral Watch card). Seven different scenarios of bleaching and mortality were observed, varying among the coral genera and between two species in the genus Pocillopora. Twenty percent of the colonies bleached, of which 50% died. Only 15% of the coral that did not bleach died. Branching genera had a higher bleaching incidence than massive and sub-massive genera. Pocillopora showed the highest bleaching susceptibility, followed by Acropora, and the highest level of mortality. Of the two species of Pocillopora considered in this study, P. eydouxi showed higher bleaching and mortality levels, while P. verrucosa bleached less and experienced only partial mortality. Our results evidenced different patterns of coral bleaching and mortality which were easily and clearly detected with the colour card method during both bleaching and a post-bleaching events.     

Facile anaerobic oxidative dehydrogenation promoted by bases: The case of copper-2,4-dihydro-1H-benzo[d][1,3]oxazine complexes

Two new 2,4-dihydro-1H-benzo[d][1,3]oxazines (L₁ and L₂) were prepared by condensation of 2-quinolinecarboxaldehyde and 2-amino-benzyl alcohols and tested as N,N’-bidentate ligands toward CuCl₂. Treatment of the resulting copper(II) derivatives with Et₃N promoted an oxidative dehydrogenation yielding the corresponding copper(I) [Cu(L-ox)Cl] complexes, 2, (L-ox = 4H-benzo[d][1,3]oxazine). The [Cu(L₂-ox)Cl] species, 2b, was characterized by single crystal X-ray diffraction, showing a trigonal geometry at the metal center and reacted with PPh₃ and CO, affording [Cu(L₂-ox)(PPh₃)Cl], 4b, and [Cu(L₂-ox)(CO)Cl], 6b, respectively. The latter species, stable in the solid state, was structurally characterized by diffraction methods and showed tetrahedral coordination of the Cu(I) ion.     

Antiproliferative effects of tocopherols (vitamin E) on murine glioma C6 cells: homologue-specific control of PKC/ERK and cyclin signaling

Chemoprevention strategies for brain tumors (specifically gliomas) are few and surprisingly poorly investigated. We have studied the effects of tocopherols (TOCs; vitamin E) on proliferation and death processes of murine glioma C6 cells. These vitamers showed different cell uptake and concentration- and time-dependent inhibitory effects on cell growth that were significant at the lowest concentrations tested (1-10 microM). However, the inhibitory potency of TOCs seemed to reflect at least in part their actual cell concentrations at steady state, with the order of magnitude gamma-TOC >or= alpha-TOC > delta-TOC approximately or = beta-TOC. Moreover, for extracellular concentrations >or=10 microM, TOCs also showed a significant cytotoxic effects due mainly to necrosis, while apoptosis was negligible. Gamma-TOC (the form showing preferential cell uptake and lowest unspecific cytotoxicity) was the most effective inhibitor of cell cycle progression (arrest in G0/G1 phase) leading to lowered expression of cyclin E and cyclin-dependent kinases 2 and 4 and overexpression of p27 (specific inhibitor of S-phase entering). According to these signals, activated ERK1/2 and PKC upstream and Rb phosphorylation downstream were decreased. In conclusion, within TOCs the gamma form exerts the most potent and specific control of cell cycle progression in C6 cells (cytostatic effect). This suggests a chemopreventive role of this form of vitamin E in gliomas.     

Sertoli cells initiate testicular innate immune responses through TLR activation

TLRs play a crucial role in early host defense against invading pathogens. In the seminiferous epithelium, Sertoli cells are the somatic nurse cells that mechanically segregate germ cell autoantigens by means of the blood-tubular barrier and create a microenvironment that protects germ cells from both interstitial and ascending invading pathogens. The objective of this study was to examine TLR expression and their functional responses to specific agonists in mouse Sertoli cells. We measured the expression of TLR2, TLR4, TLR5, and TLR6 mRNAs and confirmed by FACS analysis the presence of proteins TLR2 and TLR5 on which we focused our study. Stimulation of Sertoli cells with macrophage-activating lipopeptide-2, agonist of TLR2/TLR6, and with flagellin, agonist of TLR5, induces augmented secretion of the chemokine MCP-1. To assess the functional significance of MCP-1 production following TLR stimulation, conditioned medium from either macrophage-activating lipopeptide-2 or flagellin-treated Sertoli cells was tested for in vitro chemotaxis assay, and a significant increase of macrophage migration was observed in comparison with unstimulated conditioned medium. Moreover, we studied the role of NF-kappaB and of MAPKs in regulating TLR-mediated MCP-1 secretion by using inhibitors specific for each transduction pathway and we demonstrated a pivotal role of the IkappaB/NF-kappaB and JNK systems. In addition, TLR2/TLR6 and TLR5 stimulation induces increased ICAM-1 expression in Sertoli cells. Collectively, this study demonstrates the novel ability of Sertoli cells to potentially respond to a wide variety of bacteria through TLR stimulation.     

Specific monocyte adhesion to endothelial cells induced by oxidized phospholipids involves activation of cPLA2 and lipoxygenase

Oxidized phospholipids stimulate endothelial cells to bind monocytes, but not neutrophils, an initiating event in atherogenesis. Here, we investigate intracellular signaling events induced by oxidized phospholipids in human umbilical vein endothelial cells (HUVECs) that lead to specific monocyte adhesion. In a static adhesion assay, oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine and one of its components, 1-palmitoyl-2-oxovaleroyl-sn-glycero-3-phosphorylcholine, stimulated HUVECs to bind U937 cells and human peripheral blood monocytes but not HL-60 cells or blood neutrophils. Monocyte adhesion was dependent on protein kinases A and C, extracellular signal-regulated kinase 1/2, p38 mitogen activated protein kinases (MAPKs), and cytosolic phospholipase A(2) (cPLA(2)). Inhibition of 12-lipoxygenase (12-LOX), but not cyclooxygenases, blocked monocyte adhesion, and addition of 12-hydroxyeicosatetraenoic acid (12-HETE) mimicked the effects of oxidized phospholipids. Peroxisome proliferator-activated receptor alpha (PPARalpha) was excluded as a possible target for 12-HETE, because monocyte adhesion was still induced in endothelial cells from PPARalpha null mice. Together, our results suggest that oxidized phospholipids stimulate HUVECs to specifically bind monocytes involving MAPK pathways, which lead to the activation of cPLA(2) and 12-LOX. Further analysis of signaling pathways induced by oxidized phospholipids that lead to specific monocyte adhesion should ultimately lead to the development of novel therapeutic approaches against chronic inflammatory diseases.     

Mast cell-associated TNF promotes dendritic cell migration

Mast cells represent a potential source of TNF, a mediator which can enhance dendritic cell (DC) migration. Although the importance of mast cell-associated TNF in regulating DC migration in vivo is not clear, mast cells and mast cell-derived TNF can contribute to the expression of certain models of contact hypersensitivity (CHS). We found that CHS to FITC was significantly impaired in mast cell-deficient Kit(W-sh/W-sh) or TNF(-/)(-) mice. The reduced expression of CHS in Kit(W-sh/W-sh) mice was fully repaired by local transfer of wild-type bone marrow-derived cultured mast cells (BMCMCs), but was only partially repaired by transfer of TNF(-/)(-) BMCMCs. Thus, mast cells, and mast cell-derived TNF, were required for optimal expression of CHS to FITC. We found that the migration of FITC-bearing skin DCs into draining lymph nodes (LNs) 24 h after epicutaneous administration of FITC in naive mice was significantly reduced in mast cell-deficient or TNF(-/)(-) mice, but levels of DC migration in these mutant mice increased to greater than wild-type levels by 48 h after FITC sensitization. Mast cell-deficient or TNF(-/)(-) mice also exhibited significantly reduced migration of airway DCs to local LNs at 24 h after intranasal challenge with FITC-OVA. Migration of FITC-bearing DCs to LNs draining the skin or airways 24 h after sensitization was repaired in Kit(W-sh/W-sh) mice which had been engrafted with wild-type but not TNF(-/)(-) BMCMCs. Our findings indicate that mast cell-associated TNF can contribute significantly to the initial stages of FITC-induced migration of cutaneous or airway DCs.     

Mast cells enhance T cell activation: importance of mast cell costimulatory molecules and secreted TNF

We recently reported that mast cells stimulated via FcepsilonRI aggregation can enhance T cell activation by a TNF-dependent mechanism. However, the molecular mechanisms responsible for such IgE-, Ag- (Ag-), and mast cell-dependent enhancement of T cell activation remain unknown. In this study we showed that mouse bone marrow-derived cultured mast cells express various costimulatory molecules, including members of the B7 family (ICOS ligand (ICOSL), PD-L1, and PD-L2) and the TNF/TNFR families (OX40 ligand (OX40L), CD153, Fas, 4-1BB, and glucocorticoid-induced TNFR). ICOSL, PD-L1, PD-L2, and OX40L also are expressed on APCs such as dendritic cells and can modulate T cell function. We found that IgE- and Ag-dependent mast cell enhancement of T cell activation required secreted TNF; that TNF can increase the surface expression of OX40, ICOS, PD-1, and other costimulatory molecules on CD3(+) T cells; and that a neutralizing Ab to OX40L, but not neutralizing Abs to ICOSL or PD-L1, significantly reduced IgE/Ag-dependent mast cell-mediated enhancement of T cell activation. These results indicate that the secretion of soluble TNF and direct cell-cell interactions between mast cell OX40L and T cell OX40 contribute to the ability of IgE- and Ag-stimulated mouse mast cells to enhance T cell activation.     

N-3 fatty acids in the Mediterranean diet

Fats in the diet of countries in the Mediterranean basin are typically represented by olive oil, but the high consumptions of vegetables and to some extent also of fish result in appreciable intakes of n-3 fatty acids. In fact, various plant foods are relatively rich in the 18 carbon n-3 fatty acid, alpha linolenic acid, ALA, while the generally moderate consumption of fish, except for certain communities living close to the sea, contributes to the intake of the long-chain n-3. Although the amounts of fats in ALA-containing plant foods are low, the relatively high concentrations of this fatty acid and the large size of the portions consumed allow to reach appreciable doses of ALA, an n-3 fatty acid that has been shown to exert favourable effects on various relevant factors in cardiovascular protection. In addition, consumption of relatively small amounts of certain typical dry fruit components of the diet such as walnuts, provides a sizable supply of ALA that is also rather efficiently converted to the ALA derivative eicosapentaenoic acid (EPA). Additional rather typical wild food components of the diet in certain countries, i.e. snails and frogs, are also appreciable sources of ALA. It appears thus that the consumption of typical Mediterranean foods provides relevant intakes of n-3 fatty acids, especially ALA, that appears to be efficiently absorbed and also transformed at least to the long-chain derivative EPA.