A complex species complex: The controversial role of ecology and biogeography in the evolutionary history of Syllis gracilis Grube, 1840 (Annelida,Syllidae)

The cryptic diversity in the polychaete Syllis gracilis Grube, 1840, in the Mediterranean Sea was examined with an integrative morpho-molecular approach. Individuals of S. gracilis were collected at eleven Mediterranean localities to provide an insight into the role of brackish environments in inducing cryptic speciation. The examination of morphological features combined with a molecular genetic analysis based on a partial sequence of the 16S rRNA gene highlighted discrepancies between morphological and molecular diversity. Morphological data allowed to identify a morphotype with short appendages occurring in coralline algae communities and another one with long appendages observed in brackish-water environments and Sabellaria reefs. Multivariate analyses showed that sampling localities were the greatest source of morphological divergence, suggesting that phenotypic plasticity may play a role in local adaptations of S. gracilis populations. Molecular data showed the occurrence of four divergent lineages not corresponding to morphological clusters. Different species delimitation tests gave conflicting results, retrieving, however, at least four separated entities. Some lineages occurred in sympatry and were equally distributed in marine and brackish-water environments, excluding a biogeographic or ecological explanation of the observed pattern and suggesting instead ancient separation between lineages and secondary contact. The co-occurrence of different lineages hindered the identification of the lineage corresponding to S. gracilis sensu stricto. The discrepancy between morphological and molecular diversity suggests that different environmental and biogeographic features may interact in a complex and unpredictable way in shaping diversity patterns. An integrative approach is needed to provide a satisfactory insight on evolutionary processes in marine invertebrates.     

Lichen diversity on dolmen and menhir in the Megalithic complex of Sa Coveccada (Mores,Sardinia)

This work describes the lichen diversity found on the megalithic Dolmen of Sa Coveccada (Mores, Sardinia) until 2010. After that year, a restoration with chemical removal of lichen crusts took place, which destroyed a great part of the lichen communities. These were studied again after removal and lichen communities occurring on rock outcrops in the surroundings of the Dolmen and on a contiguous menhir were investigated as well for comparison. Before the restoration, 33 species had been recorded on the Dolmen, most being crustose, followed by foliose and fruticose forms. Among these, eight species are regarded as rare in Sardinia and five rare at lower elevations. Most of the recorded species are typical for eutrophic substrates and for meso- to xerophytic conditions. Studies on lichen diversity on archaeological monuments in Sardinia are limited. This is the first report on the lichens of a Sardinian dolmen. This paper questions whether the lichen diversity of such monuments should be preserved as lichens have been an important part of the monument ecosystem and of the landscape for many centuries. This work also aims to improve collaboration among lichen and monument experts, in order to avoid hasty restoration decisions.     

Genetic linkage of hyper-IgE syndrome to chromosome 4.

The hyper-IgE syndrome (HIES) is a rare primary immunodeficiency characterized by recurrent skin abscesses, pneumonia, and highly elevated levels of serum IgE. HIES is now recognized as a multisystem disorder, with nonimmunologic abnormalities of the dentition, bones, and connective tissue. HIES can be transmitted as an autosomal dominant trait with variable expressivity. Nineteen kindreds with multiple cases of HIES were scored for clinical and laboratory findings and were genotyped with polymorphic markers in a candidate region on human chromosome 4. Linkage analysis showed a maximum two-point LOD score of 3.61 at recombination fraction of 0 with marker D4S428. Multipoint analysis and simulation testing confirmed that the proximal 4q region contains a disease locus for HIES.     

A polymorphism in the human serotonin 5-HT2A receptor gene may protect against systemic sclerosis by reducing platelet aggregation

Introduction

Platelet aggregation may contribute to the pathogenesis of systemic sclerosis: following activation, platelets release significant amounts of serotonin – which promotes vasoconstriction and fibrosis, and further enhances aggregation. The C+1354T polymorphism in the exonic region of the serotonin 2A receptor gene determining the His452Tyr substitution was associated with blunted intracellular responses after serotonin stimulation, and may have a role in susceptibility to scleroderma.

Methods

One hundred and fifteen consecutive systemic sclerosis patients and 140 well-matched healthy control individuals were genotyped by sequence-specific primer-PCR for the His⁴⁵²Tyr substitution of the serotonin 2A receptor gene, and associations were sought with scleroderma and its main clinical features. The functional relevance of the His⁴⁵²Tyr substitution was also assessed by evaluating the aggregation of platelet-rich plasma from His⁴⁵²/His⁴⁵² and His⁴⁵²/Tyr⁴⁵² healthy individuals after stimulation with adenosine diphosphate ± serotonin.

Results

The T allele of the C+1354T polymorphism was underrepresented in scleroderma patients compared with control individuals (5.2% versus 12.4%, P < 0.001, chi-square test and 1,000-fold permutation test) and its carriage reduced the risk for systemic sclerosis (odds ratio = 0.39, 95% confidence interval = 0.19 to 0.85, P < 0.01). Platelets from His⁴⁵²/Tyr⁴⁵² healthy subjects more weakly responded to serotonin stimulation compared with platelets from His⁴⁵²/His⁴⁵² individuals (3.2 ± 2.6-fold versus 9.6 ± 8.6-fold increase in aggregation, P = 0.017 by Kolmogorov–Smirnov test and P = 0.003 after correction for baseline adenosine diphosphate-induced aggregation values).

Conclusion

The His⁴⁵²Tyr substitution may influence susceptibility to systemic sclerosis by altering platelet aggregation in response to serotonin.     

TGFbeta protects mesoangioblasts from apoptosis via sphingosine kinase-1 regulation

Mesoangioblasts are vessel-derived progenitor cells that can be induced to differentiate into different cell types of the mesoderm such as muscle and bone. Here we examined the role of transforming growth factor-beta (TGFbeta), a pleiotropic cytokine that plays a major role in development and specifically induces smooth muscle differentiation of mesoangioblasts, in the regulation of death and survival of these cells. TGFbeta exerts a marked anti-apoptotic action in mesoangioblasts with a mechanism involving regulation of sphingosine kinase 1 (SphK1), one of the isoforms responsible for S1P formation. Treatment with the cytokine efficaciously protected mesoangioblasts from apoptosis induced by serum starvation or staurosporine treatment assessed by various means such as activation of caspase-3, determination of cytoplasmic histone-associated-DNA-fragments and PE-AnnexinV staining. The protective action of TGFbeta from staurosporine-induced apoptosis was strongly reduced when the SphK activity was inhibited by drugs, when SphK1 but not SphK2 was downregulated by specific siRNA and when a SphK1 dominant negative mutant was overexpressed. Staurosporine treatment induced down-regulation of both SphK isoforms and TGFbeta rescued SphK1 but not SphK2 expression. Interestingly, TGFbeta strongly enhanced SphK activity during staurosporine-induced cell death. Both TGFbeta-induced SphK1 up-regulation and TGFbeta anti-apoptotic action were found to be dependent on p42/44 MAPK activation.     

High performance liquid chromatographic enantioseparation of chiral bridged polycyclic compounds on chiralcel OD-H and chiralpak OT(+)

The HPLC enantiomeric separation of 29 racemic bridged polycyclic compounds was examined on commercially available Chiralcel OD-H and Chiralpak OT(+) columns. The separations were evaluated under normal-phase mode (hexane containing mobile phase) for Chiralcel OD-H and under normal-phase as well as under reversed-phase mode (pure MeOH, temperature 5 degrees C) for Chiralpak OT(+). Almost all compounds were resolved either on Chiralcel OD-H or on Chiralpak OT(+), in some cases on both. The use of trifluoroacetic acid (TFA), as modifier of the hexanic mobile phase, had a beneficial effect on the enantioseparation of some polar and acidic compounds on Chiralcel OD-H. The influence of small chemical structural modifications of the analytes on the enantioseparation behavior is discussed. A structure-retention relationship has been observed on both stationary phases. This chromatographic evaluation may provide some information about the chiral recognition mechanism: in the case of Chiralcel OD-H, hydrogen bonding, pi-pi and distereoselective repulsive are supposed to be the major analyte-CSP interactions. In the case of Chiralpak OT(+), a reversed-phase enantioseparation could take place through hydrophobic interactions between the aromatic moiety of the analytes and the chiral propeller structure of the CSP. The synthesis of some unknown racemic bromobenzobicyclo[2.2.1] analytes is also described.     

Impact of sulphur dioxide on the viability,culturability, and volatile phenol production of Dekkera bruxellensis in wine

Viability and culturability of eight Dekkera bruxellensis strains in wine along with the accumulation of volatile phenols in response to increasing concentrations of molecular sulphur dioxide (mSO₂) were investigated. mSO₂ concentrations up to 1 mg/L induced the non-culturable state of a portion of the population in all the strains to a different extent for each strain, although the cells were still viable. At 1.4 mg/L mSO₂, cells were non-culturable, though 0.38–29.01 % of cells retained their viability. When exposed to 2.1 mg/L mSO₂, viable cells were not detected. Up to 0.24 mg/L 4-vinylguaiacol and up to 0.73 mg/L 4-ethylphenol were accumulated by non-culturable and dead Dekkera bruxellensis strains, respectively. The concentration of mSO₂ needed for the transition from viable to non-culturable state of D. bruxellensis strains was higher in wine than in synthetic wine medium. The volatile phenols accumulated in wine were different from those produced in synthetic wine medium, although their accumulation kinetics were similar.     

Neural control of early myogenic differentiation in cultures of mouse somites

Neural tubes, with flanking somite streaks, were isolated from mouse embryos ranging in age from 8 to 11 days post coitus (dpc). The somites were further dissected along the neural tube to obtain one somite streak associated with the neural tube and the other free of nerve cells. The two groups of somites (with and without neural tubes) were dissociated to single cell suspension by a brief incubation with EDTA. High-density micro-mass cultures were established from these two groups of cells and the extent of cell differentiation was assayed by staining the cultures with an anti-myosin antibody. The results obtained indicated that during early somitogenesis (8.5 dpc) the presence of cells from neural tube is necessary for the emergence of myosin-positive cells in culture. At later stages (10.5 dpc), however, the total number of myosin-positive cells appearing in culture is largely independent from the presence of nerve cells. At these later stages, the presence of nerve cells inhibited the occurrence of fusion in myogenic cells. Many multinucleated myotubes appeared in cultures of somitic cells in the absence of nerve cells, but very few in their presence. The possible relationship of these data with the appearance of mononucleated differentiated cells in myotomes in vivo and the possible neural control of this stage of myogenesis are discussed.     

Effect of phorbol esters and liposome-delivered phospholipids on the differentiation program of normal and dystrophic satellite cells

Satellite cells, isolated from hind limb of normal C57BL/6J mice, differentiate in culture in the presence of concentrations of phorbol esters which inhibit differentiation of embryonic myoblasts. However, if phosphatidylserine containing liposomes were added to the culture medium together with TPA, differentiation of satellite cells was reversibly inhibited. Under these conditions, the withdrawal of these cells from the cell cycle still occurred as in untreated cells. Phosphatidylserine liposomes alone or liposomes containing phosphatidylcholine (either alone or in combination with TPA) had no effect on satellite cell differentiation. In the case of satellite cells from dystrophic C57BL/6J/dydy mice, TPA addition (0.1 microM) to the culture medium partially (about 70%) inhibited morphological and biochemical differentiation. This effect could be prevented by preincubating dystrophic satellite cells with liposomes containing phosphatidylcholine but not other phospholipids. These data indicate that it is possible to change the sensitivity to TPA of satellite cells by modifying the phospholipid composition of their plasma membrane. Possible relationships of these phenomena with activation of protein kinase C or phosphatidylinositol breakdown have been investigated. The results obtained are discussed with regard to possible modulation of the intracellular response to agonist binding.