Identification and relevance of the CD95-binding domain in the N-terminal region of ezrin

The CD95 (Fas/APO-1) linkage to the actin cytoskeleton through ezrin is an essential requirement for susceptibility to the CD95-mediated apoptosis in CD4+ T cells. We have previously shown that moesin was not involved in the binding to CD95. Here we further support the specificity of the ezrin/CD95 binding, showing that radixin did not bind CD95. The ezrin region specifically and directly involved in the binding to CD95 was located in the middle lobe of the ezrin FERM domain, between amino acids 149 and 168. In this region, ezrin, radixin, and moesin show 60-65% identity, as compared with the 86% identity in the whole FERM domain. Transfection of two different human cell lines with a green fluorescent protein-tagged ezrin mutated in the CD95-binding epitope, induced a marked inhibition of CD95-mediated apoptosis. In these cells, the mutated ezrin did not co-localize or co-immunoprecipitate with CD95. Further analysis showed that the mutated ezrin, while unable to bind CD95, was fully able to bind actin, thus preventing the actin linkage to CD95. Altogether, our results support the specificity of ezrin in the association to CD95 and the importance of the ezrin-to-CD95 linkage in CD95-mediated apoptosis. Moreover, this study suggests that a major role of ezrin is to connect CD95 to actin, thus allowing the CD95 polarization on the cells and the occurrence of the following multiple cascades of the CD95 pathway.     

Molecular evolution of olfactomedin

Olfactomedin is a secreted polymeric glycoprotein of unknown function,originally discovered at the mucociliary surface of the amphibian olfactoryneuroepithelium and subsequently found throughout the mammalian brain. As afirst step toward elucidating the function of olfactomedin, itsphylogenetic history was examined to identify conserved structural motifs.Such conserved motifs may have functional significance and provide targetsfor future mutagenesis studies aimed at establishing the function of thisprotein. Previous studies revealed 33% amino acid sequence identity betweenrat and frog olfactomedins in their carboxyl terminal segments. Furtheranalysis, however, reveals more extensive homologies throughout themolecule. Despite significant sequence divergence, cysteines essential forhomopolymer formation such as the CXC motif near the amino terminus areconserved, as is the characteristic glycosylation pattern, suggesting thatthese posttranslational modifications are essential for function.Furthermore, evolutionary analysis of a region of 53 amino acids of fish,frog, rat, mouse, and human olfactomedins indicates that an ancestralolfactomedin gene arose before the evolution of terrestrial vertebrates andevolved independently in teleost, amphibian, and mammalian lineages.Indeed, a distant olfactomedin homolog was identified in Caenorhabditiselegans. Although the amino acid sequence of this invertebrate protein islonger and highly divergent compared with its vertebrate homologs, theprotein from C. elegans shows remarkable similarities in terms of conservedmotifs and posttranslational modification sites. Six universally conservedmotifs were identified, and five of these are clustered in the carboxylterminal half of the protein. Sequence comparisons indicate that evolutionof the N-terminal half of the molecule involved extensive insertions anddeletions; the C-terminal segment evolved mostly through point mutations,at least during vertebrate evolution. The widespread occurrence ofolfactomedin among vertebrates and invertebrates underscores the notionthat this protein has a function of universal importance. Furthermore,extensive modification of its N-terminal half and the acquisition of aC-terminal SDEL endoplasmic-reticulum- targeting sequence may have enabledolfactomedin to adopt new functions in the mammalian central nervoussystem.     

Amblyomma Tigrinum (Acari: Ixodidae) in Relation to Phytogeography of Central-Northern Argentina with Notes on Hosts and Seasonal Distribution

The findings of Amblyomma tigrinum in continental Argentina north of 40°S are presented according to phytogeographic domains (Andean–Patagonic, Amazonian and Chaco) and the seasonal distribution is depicted on a monthly basis. A total of 718 adult ticks and four nymphs were found. A. tigrinum ticks were present in all domains. Adult ticks were found all year round but they were more abundant during the summer. Most ticks were found on domestic dogs but the survey has a bias to domestic hosts. It is speculated that the cycle of immature is bound to shelters that mitigate extreme climatic conditions, thus explaining the finding of this tick species in contrasting ecological areas.     

Analysis of bacterial DNA in skin and muscle of the Tyrolean iceman offers new insight into the mummification process

About 80 sequences (16s ribosomal RNA gene) of bacterial DNA in samples of skin and muscle taken directly from the Tyrolean iceman (3350-3100 years B.C.) or recovered during the 1992 archaeological expedition at the Alpine site were analyzed to obtain clues to the natural mummification process that allowed the corpse of the Neolithic shepherd/hunter to be preserved for more than 5,000 years. The investigation was made more complex by the fact that the surface of the mummy had been swabbed with phenol soon after the discovery (September 19, 1991). Our results show that no trace of microbial DNA is left on the actual surface of the body, while the untreated skin still bears the remains of large numbers of bacteria belonging to the genera Sphingomonas, Afipia, Curtobacterium, Microbacterium, Agromyces, and others. Compared to the untreated skin, the iceman's muscle is also very rich in bacterial DNA. However, this DNA comes, with few exceptions, from the species Clostridium algidicarnis. The sharp difference in the bacterial DNA composition of skin and muscle suggests that the remains of the original cadaveric microflora of the latter have not disappeared during the iceman's taphonomic history. On the other hand, the massive presence of C. algidicarnis, a cold-adapted sporigenous, the DNA of which was previously (Ubaldi et al. [1998] Am. J. Phys. Anthropol. 107:285-295) found in the soft tissue of a naturally desiccated Andean mummy, indicates that the hypothesis that the iceman's corpse underwent rapid dehydration by the effect of a warm wind (f?hn) is no longer plausible. The results best fit with the hypothesis (Bereuter et al. [1997] Chem. Eur. J. 7:1032-1038) that the body was first covered by snow and ice, and then underwent thawing and, finally, desiccation.     

Learning Environment,Preparedness and Satisfaction in Osteopathy in Europe: The PreSS Study

Objective

1) to assess the preparedness to practice and satisfaction in learning environment amongst new graduates from European osteopathic institutions; 2) to compare the results of preparedness to practice and satisfaction in learning environment between and within countries where osteopathy is regulated and where regulation is still to be achieved; 3) to identify possible correlations between learning environment and preparedness to practice.

Method

Osteopathic education providers of full-time education located in Europe were enrolled, and their final year students were contacted to complete a survey. Measures used were: Dundee Ready Educational Environment Measure (DREEM), the Association of American Medical Colleges (AAMC) and a demographic questionnaire. Scores were compared across institutions using one-way ANOVA and generalised linear model.

Results

Nine European osteopathic education institutions participated in the study (4 located in Italy, 2 in the UK, 1 in France, 1 in Belgium and 1 in the Netherlands) and 243 (77%) of their final-year students completed the survey. The DREEM total score mean was 121.4 (SEM: 1.66) whilst the AAMC was 17.58 (SEM:0.35). A generalised linear model found a significant association between not-regulated countries and total score as well as subscales DREEM scores (p<0.001). Learning environment and preparedness to practice were significantly positively correlated (r=0.76; p<0.01).

Discussion

A perceived higher level of preparedness and satisfaction was found amongst students from osteopathic institutions located in countries without regulation compared to those located in countries where osteopathy is regulated; however, all institutions obtained a ‘more positive than negative’ result. Moreover, in general, cohorts with fewer than 20 students scored significantly higher compared to larger student cohorts. Finally, an overall positive correlation between students’ preparedness and satisfaction were found across all institutions recruited.     

Nanospaces between endoplasmic reticulum and mitochondria as control centres of pancreatic β-cell metabolism and survival

Nanometre-scale spaces between organelles represent focused nodes for signal transduction and the control of cellular decisions. The endoplasmic reticulum (ER) and the mitochondria form dynamic quasi-synaptic interaction nanodomains in all cell types examined, but the functional role of these junctions in cellular metabolism and cell survival remains to be fully understood. In this paper, we review recent evidence that ER Ca(2+) channels, such as the RyR and IP(3)R, can signal specifically across this nanodomain to the adjacent mitochondria to pace basal metabolism, with focus on the pancreatic β-cell. Blocking these signals in the basal state leads to a form of programmed cell death associated with reduced ATP and the induction of calpain-10 and hypoxia-inducible factors. On the other hand, the hyperactivity of this signalling domain plays a deleterious role during classical forms of apoptosis. Thus, the nanospace between ER and mitochondria represents a critical rheostat controlling both metabolism and programmed cell death. Many aspects of the mechanisms underlying this control system remain to be uncovered, and new nanotechnologies are required understand these domains at a molecular level.