Synthesis,preferred conformation,protease stability,and membrane activity of heptaibin,a medium‐length peptaibiotic

The medium‐length peptaibiotics are characterized by a primary structure of 14–16 amino acid residues. Despite the interesting antibiotic and antifungal properties exhibited by these membrane‐active peptides, their exact mechanism of action is still unknown. Here, we present our results on heptaibin, a 14‐amino acid peptaibiotic found to exhibit antimicrobial activity against Staphylococcus aureus. We carried out the very challenging synthesis of heptaibin on solid phase and a detailed conformational analysis in solution. The peptaibiotic is folded in a mixed 3₁₀‐/α‐helix conformation which exhibits a remarkable amphiphilic character. We also find that it is highly stable toward degradation by proteolytic enzymes and nonhemolytic. Finally, fluorescence leakage experiments using small unilamellar vesicles of three different compositions revealed that heptaibin, although uncharged, is a selective compound for permeabilization of model membranes mimicking the overall negatively charged surface of Gram‐positive bacteria. This latter finding is in agreement with the originally published antimicrobial activity data. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.     

An aggregation framework to link indicators associated with multifunctional land use to the stakeholder evaluation of policy options

In the last decade efforts have been carried out by the scientific community aimed at building integrated frameworks to support the decision-making process when sustainability issues are addressed. This paper proposes a further advancement in integrated assessment procedures by setting up an operational multi-scale and transparent framework, which comprises the assessment of European regions in terms of sustainability, and the identification of the impact that policy options might have on the sustainability of these regions. The framework is designed for use in ex ante sustainability impact assessment of policy scenarios on multifunctionality of land use and integrates economic, environmental and social issues across a variety of sectors (agriculture, forestry, transport, tourism and energy). The proposed method provides a conceptual framework applicable at different scales (European, regional), and takes into account the great variability of European regions. The described methodology is based on linear additive models to weight and aggregate selected indicators to a set of land use functions identified to describe the goods and services provided by the different land uses that summarise the most relevant economic, environmental and social issues of a region. The framework is designed to allow the evaluation of impacts at an international scale (e.g. the European Union), or on selected regions.The aggregation framework can be used to evaluate the impact that policy options have on the sustainability of multifunctional land use systems with competing demands. A conceptual envelope, called the “trade-off evaluation space”, delineates all possible developments in the functions of the land. The sustainability limits identify the subset of ‘acceptable’ policy options within the trade-off evaluation space, so that the distance of each land use function from sustainability limits can be estimated and trade-offs between the different functions of the multifunctional land use system can be identified. The proposed methodology is adaptable to different contexts: if the assumption is taken that all land use functions are equally weighted the framework can be used to analyse policy cases and take decisions on policy options at the European or regional level. However, at the local-scale the framework can also be applied through a participatory approach and the distribution of weights can be rediscussed with local stakeholders. In both cases the proposed system can be used as a tool for discussion among all interested parties.     

Comparison of curricula in radiation technology in the field of radiotherapy in selected European Union countries

Background

Radiation technology is a discipline of medical science which deals with diagnostics, imaging and radiotherapy, that is treatment by ionizing radiation.

Aim

To present and compare the existing curricula of radiation technology in selected EU countries.

Materials and methods

The research work done for the purpose of the comparative analysis was based on the methods of diagnostic test and document analysis.

Results

The comparison of curricula in selected countries, namely Austria, France, the Netherlands and Poland, showed that admission criteria to radiation technology courses are varied and depend on regulations of respective Ministries of Health. The most restrictive conditions, including written tests in biology, chemistry and physics, and psychometric test, are those in France. Contents of basic and specialist subject groups are very similar in all the countries. The difference is in the number of ECT points assigned to particular subjects and the number of course hours offered. The longest practical training is provided in the Netherlands and the shortest one in Poland. The duration of studies in the Netherlands is 4 years, while in Poland it is 3 years. Austria is the only country to offer extra practical training in quality management.

Conclusion

Graduates in the compared EU countries have similar level of qualifications in the fields of operation of radiological equipment, radiotherapy, nuclear medicine, foreign language and specialist terminology in the field of medical and physical sciences, general knowledge of medical and physical sciences, and detailed knowledge of radiation technology.     

Systematic quantification of peptides/proteins in urine using selected reaction monitoring

The evaluation of biomarkers in bodily fluids necessitates the development of robust methods to quantify proteins in a complex background, using large sets of samples. The ability to multiplex numerous analytes in a single assay expedites the process. Liquid chromatography-mass spectrometry (LC-MS) analyses performed in selected reaction monitoring (SRM) in conjunction with stable isotope dilution MS present an effective way to detect and quantify biomarker candidates in bodily fluids. The strategy presented involves an initial qualification of predefined sets of proteins in urine. The technique was applied to detect and quantify peptides in urine samples as surrogates for a few endogenous proteins. Multiplexed assays were developed to analyze proteins associated with bladder cancer; a few exogenous proteins were added as internal standards. The sample preparation and the analytical protocols were optimized to ensure reproducibility, analytical precision, and quantification limits in the low nanogram per milliliter range. Analyses were performed using known amounts of isotopically labeled peptides. Systematic replication of the measurements indicated intra-assay and inter-assay variability, with CVs in the range of 10%. The differences measured for two targeted proteins were correlated with their level of expression in the corresponding tumors using immunohistochemistry.     

The K153R polymorphism in the myostatin gene and muscle power phenotypes in young, non-athletic men

The Lys(K)153Arg(R) polymorphism in exon 2 (rs1805086, 2379 A>G replacement) of the myostatin (MSTN) gene is a candidate to influence skeletal muscle phenotypes. We examined the association between the MSTN K153R polymorphism and 'explosive' leg power, assessed during sprint (30 m) and stationary jumping tests [squat (SJ) and counter-movement jumps (CMJ)] in non-athletic young adults (University students) [n = 281 (214 men); age: 21-32 years]. We also genotyped the MSTN exonic variants E164K (rs35781413), I225T, and P198A, yet no subject carried any of these variant MSTN alleles. As for the K153R polymorphism, we found only one woman with the KR genotype; thus, we presented the results only for men. The results of a one-way ANCOVA (with age, weight and height entered as covariates) showed that men with the KR genotype (n = 15) had a worse performance in vertical jumps compared with those with the KK genotype [SJ: vertical displacement of center of gravity (CG) of 35.17 ± 1.42 vs. 39.06 ± 0.39 cm, respectively, P = 0.009; CMJ: vertical displacement of CG of 36.44 ± 1.50 vs. 40.63 ± 0.41 cm, respectively, P = 0.008]. The results persisted after adjusting for multiple comparisons according to Bonferroni. Performance in 30 m sprint tests did however not differ by K153R genotypes. In summary, the MSTN K153R polymorphism is associated with the ability to produce 'peak' power during muscle contractions, as assessed with vertical jump tests, in young non-athletic men. Although more research is still needed, this genetic variation is among the numerous candidates to explain, alone or in combination with other polymorphisms, individual variations in muscle phenotypes.     

Protein 4.1B contributes to the organization of peripheral myelinated axons

Neurons are characterized by extremely long axons. This exceptional cell shape is likely to depend on multiple factors including interactions between the cytoskeleton and membrane proteins. In many cell types, members of the protein 4.1 family play an important role in tethering the cortical actin-spectrin cytoskeleton to the plasma membrane. Protein 4.1B is localized in myelinated axons, enriched in paranodal and juxtaparanodal regions, and also all along the internodes, but not at nodes of Ranvier where are localized the voltage-dependent sodium channels responsible for action potential propagation. To shed light on the role of protein 4.1B in the general organization of myelinated peripheral axons, we studied 4.1B knockout mice. These mice displayed a mildly impaired gait and motility. Whereas nodes were unaffected, the distribution of Caspr/paranodin, which anchors 4.1B to the membrane, was disorganized in paranodal regions and its levels were decreased. In juxtaparanodes, the enrichment of Caspr2, which also interacts with 4.1B, and of the associated TAG-1 and Kv1.1, was absent in mutant mice, whereas their levels were unaltered. Ultrastructural abnormalities were observed both at paranodes and juxtaparanodes. Axon calibers were slightly diminished in phrenic nerves and preterminal motor axons were dysmorphic in skeletal muscle. βII spectrin enrichment was decreased along the axolemma. Electrophysiological recordings at 3 post-natal weeks showed the occurrence of spontaneous and evoked repetitive activity indicating neuronal hyperexcitability, without change in conduction velocity. Thus, our results show that in myelinated axons 4.1B contributes to the stabilization of membrane proteins at paranodes, to the clustering of juxtaparanodal proteins, and to the regulation of the internodal axon caliber.     

Fatal attraction phenomenon in humans: cat odour attractiveness increased for toxoplasma-infected men while decreased for infected women

Background

Latent toxoplasmosis, a lifelong infection with the protozoan Toxoplasma gondii, has cumulative effects on the behaviour of hosts, including humans. The most impressive effect of toxoplasmosis is the “fatal attraction phenomenon,” the conversion of innate fear of cat odour into attraction to cat odour in infected rodents. While most behavioural effects of toxoplasmosis were confirmed also in humans, neither the fatal attraction phenomenon nor any toxoplasmosis-associated changes in olfactory functions have been searched for in them.

Principal Findings

Thirty-four Toxoplasma-infected and 134 noninfected students rated the odour of urine samples from cat, horse, tiger, brown hyena and dog for intensity and pleasantness. The raters were blind to their infection status and identity of the samples. No signs of changed sensitivity of olfaction were observed. However, we found a strong, gender dependent effect of toxoplasmosis on the pleasantness attributed to cat urine odour (p = 0.0025). Infected men rated this odour as more pleasant than did the noninfected men, while infected women rated the same odour as less pleasant than did noninfected women. Toxoplasmosis did not affect how subjects rated the pleasantness of any other animal species'' urine odour; however, a non-significant trend in the same directions was observed for hyena urine.

Conclusions

The absence of the effects of toxoplasmosis on the odour pleasantness score attributed to large cats would suggest that the amino acid felinine could be responsible for the fatal attraction phenomenon. Our results also raise the possibility that the odour-specific threshold deficits observed in schizophrenia patients could be caused by increased prevalence of Toxoplasma-infected subjects in this population rather than by schizophrenia itself. The trend observed with the hyena urine sample suggests that this carnivore, and other representatives of the Feliformia suborder, should be studied for their possible role as definitive hosts in the life cycle of Toxoplasma.