Sublimity and Freedom in Schiller's "Mary Stuart" and "The Maid of Orleans"

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Comparative assessment of erythrocyte sphingolipid levels as potential cardiovascular health markers in women from Libya and Serbia: a small-scale study

Aim: Cardiovascular diseases (CVDs) represent the major cause of morbidity and mortality worldwide including Libya, where they account for 43% of all deaths. Sphingolipids are involved in the pathology of numerous diseases including cardiovascular diseases and are proposed as potential biomarkers of cardiovascular health that could be more effective compared to traditional clinical biomarkers. The aim of this study was to determine the sphingolipid content in the erythrocyte membrane of Libyan migrant and Serbian resident women. In addition, to examine if sphingolipid levels could be used as a novel indicator of cardiovascular risk, we evaluated possible correlations with some well-established biomarkers of cardiovascular health. Materials and Methods: A total of 13 Libyan and 15 Serbian healthy women participated in the study. The high-performance version thin-layer chromatography (HPTLC) using the image analysis tool JustTLC was applied for quantification of erythrocytes’ sphingolipids. Results: Lower mean values of erythrocytes’ sphingolipids and cholesterol concentrations were found in the group of Libyan emigrants compared to Serbian resident women. Besides, in this group of apparently healthy women (n = 28), the sphingolipid content of erythrocytes was inversely related to the Omega-3 index (r =-0.492, p = 0.008) and directly linked to vitamin D status (r = 0.433, p = 0.021) and membrane cholesterol levels (r = 0.474, p = 0.011). Conclusion: The erythrocytes’ sphingolipid levels should be measured/assessed as an additional biomarker of CV health, by applying a simple and routine method. Still, further investigation in a larger population-specific context is warranted

An improved HPLC-DAD method for simultaneously measuring phenolics in the leaves of Tilia platyphyllos and Ailanthus altissima

Phenolic compounds are one of the most important groups of secondary metabolites in plants, with various physiological functions. Their diverse chemical structure and susceptibility to auto-oxidation, and their ability to act as both antioxidants and prooxidants in the presence of metal ions, are some of the main reasons why it is difficult to measure phenolic groups in plant tissues accurately. We present an optimized extraction and hydrolysis procedure which preserves the original chemical structure of phenolics. The presented HPLC method was improved to enable the simultaneous separation and quantification of 39 compounds from different phenolic subclasses (benzoic acids, hydroxycinnamic acids, flavones, flavonols, flavanones, flavanols, isoflavones, anthocyanidins; aglycones and glycosides). Recovery after extraction and complete hydrolysis of glycosides was more than 95% and 84%, respectively. The method was applied to the analysis and comparison of phenolic profiles in the leaves of two species, Ailanthus altissima (Mill.) Swingle and Tilia platyphyllos Scop. from an urban forest park and busy traffic area. The presence of cyanidin glycosides in A. altissima leaves was reported for the first time. Results indicated higher accumulation of phenolics, with two hydroxyl groups in the ortho- position, than flavonoids, with a monohydroxy substitution in the leaves of both species from a busy traffic area

In silico structural survey of newly identified late embryogenesis abundant proteins (LEAPs) from Ramonda serbica and their structure - function relationship

Desiccation or extreme water loss leads to protein denaturation, aggregation, and degradation and impairs membrane lipid fluidity, resulting in loss of membrane integrity at the cellular level. The induction of late embryogenesis abundant proteins (LEAPs) is considered an essential component of desiccation tolerance strategy in so-called resurrection plants. This heterogeneous group of hydrophilic, non-globular proteins is characterised by a high structural plasticity that allows them to adopt a random conformation in aqueous solutions that transforms into α-helices during dehydration [1]. Therefore, LEAPs can interact with various ligands and partners, including ion sequestration and stabilisation of membranes and enzymes during freezing or drying [2]. Our new transcriptome database of an endemic resurrection species Ramonda serbica allowed us to identify 164 members of the LEA gene family. LEAPs of this sample data have an average primary sequence similarity and identity of 10% and 6%, respectively, but with a high variance (141 and 108), which means that the sample proteins can be classified based on domain homology. The averaging is based on multiple sequence alignment and the variance is estimated using pairwise sequence alignment scores. Accordingly, all identified LEAPs were clustered into six groups based on protein families (PFAM). Among these groups, LEAPs differ significantly in their secondary structure, disorder propensity and aggregation potential. Furthermore, we built homology models using PDB structures as templates. For each group, an ensemble of superimposed 3D homology models was analyzed. The information obtained from the representative structural models is key to understanding the function of LEAPs and the regulation of their intrinsic structural disorder-to-order transition during desiccation. This will pave the way for the identification of LEAPs endogenous partners and their targets in the cell and provide further insights into the protective mechanisms of desiccation tolerance.PDB50: A special symposium celebrating the 50th anniversary of Protein Data Bank, 4-5 May, 2021

Strukturna karakterizacija proteina zastupljenih u kasnoj fazi embriogeneze iz biljke Ramonda Serbica : Potencijalni inhibitor agregacije α‐ sinukleina

Ramonda serbica is an endemic and resurrection plant species that can survive extreme dehydration even over months. Desiccation (loss of >95% of cellular water) leads to protein denaturation, aggregation, and degradation and impairs membrane lipid fluidity, resulting in loss of membrane integrity at the cellular level. The induction of late embryogenesis abundant proteins (LEAPs) is considered an essential component of desiccation tolerance strategy in so-called resurrection plants. This heterogeneous group of anhydrobiosis-related intrinsically disordered proteins (IDPs) is characterized by high structural plasticity enabling them to interact with various ligands and partners, including ion sequestration and stabilization of membranes and enzymes during freezing or drying. the aim of our research is to assess the potential of selected RsLEAPs to inhibit the aggregation of α-synuclein, paving the way for new therapeutic strategies against neurodegenerative disorders, such as Parkinson’s disease. Our new transcriptome database of R. serbica leaves allowed us to identify around 165 members of LEA protein family. Based on multiple sequence alignment, secondary structure prediction and 3D structure modelling we classified identified LEAPs into six groups (according to the Pfam database) and showed that more than 50% of identified LEAPs exhibited a high propensity to form α-helices. As predicted by several bioinformatic tools, more than 70% of identified LEAPs were found to be highly disordered. By using molecular dynamic simulations, we identified the most favourable conformations of representative LEAPs and showed the loss of the secondary, α-helical structure in water, in contrast to globular proteins. Structural characterization of LEAPs is a key to understand their function and regulation of their intrinsic structural disorder-to-order transition during desiccation. These findings will promote transformative advancements in various fields, such as the development of new strategies in neurodegenerative disorders, cell preservation technology and the improvement of crop drought tolerance.Ramonda serbica endemska vrsta, i biljka vaskrsnica, sposobna da preživi u uslovima ekstremne dehidratacije tokom perioda dužeg od mesec dana. Desikacija (gubitak preko 95 % vode u ćeliji) dovodi do denaturacije, agregacije i degradacije proteina, i utiče na fluidnost membrana, što finalno dovodi do gubitka integriteta ćelije. Prisustvo proteina zastupljenih u kasnoj fazi embriogeneze (late embryogenesis abundant proteins – LEAPs) se smatra esencijalnim delom strategije tolerancije na desikaciju kod vaskrsnica. Ovu heterogenu grupu prirodno neuređenih proteina, povezanih sa anhidrobiozom, odlikuje visoka strukturna plastičnost koja im omogućava interakciju sa brojnim ligandima i partnerima. LEA proteini su uključeni u heliranje jona, stabilizaciju membrana i enzima tokom zamrzavanja ili suše. Cilj našeg istraživanja je procena potencijala izabranog LEA proteina iz ramonde da inhibira agregaciju α-sinukleina, otvarajući put ka razvoju novih terapija za lečenje neurodegenerativnih poremećaja poput Parkinskonove bolesti. Analiziranjem transkriptoma listova R. serbica i formiranjem baze podataka identifikovano je oko 165 proteina koji pripadaju LEA proteinskoj familiji. Na osnovu višestrukog poravnjanja aminokiselinskih sekvenci, predviđanja sekundarne strukture i 3D strukturnog modelinga, identifikovani LEA proteini su podeljeni u šest grupa (prema Pfam bazi podataka) i pokazano je sa velikom verovatnoćom da je više od 50 % LEA proteina u mogućnosti da formira α-helikse. Pomoću nekoliko bioinformatičkih alata predviđeno je da više od 70 % identifikovanih LEA proteina formira visoko neuređenu strukturu. Korišćenjem simulacije molekularne dinamike, identifikovane su najpovoljnije konformacije reprezentativnih LEA proteina. Tom prilikom je kod LEA proteina uočen gubitak sekundarne α-heliksne strukture u vodi, za razliku od globularnih proteina kada je ova struktura favorizovana. Strukturna karakterizacija LEA proteina je ključna za razumevanje njihove funkcije i regulaciju njihovog prelaska iz neuređene u uređenu konformaciju tokom desikacije. Ova saznanja bi trebalo da omoguće značajna napredovanja na različitim poljima, kao što je razvoj novih strategija u borbi protiv neurodegenerativnih poremećaja, tehnologija čuvanja zamrznutih ćelija, kao i na povećanje otpornosti useva na sušu

Vitamin D Deficiency Among Medical Students in Osijek, Croatia

Aim: This study aimed to evaluate serum levels of 25-OH D3 (calcidiol) among students of the Faculty of Medicine Osijek, Croatia, thereby determining to what extent vitamin D deficiency is present. Methods: The present cross-sectional analysis was based on data collected from 60 participants. Blood sampling was done in March 2021. Concentrations of 25-OH D3 were measured using LC/MS-MS procedure on Shimadzu LCMS 8050 and RECIPE kit for serum levels of 25-OH-D3. Results: The study was conducted on a sample of 60 respondents aged 19 to 28, of whom 16 were men and 44 were women. All subjects had a 25-OH D3 deficiency (0.05). Conclusion: Vitamin D deficiency was detected in all subjects. In addition to the results of several other studies conducted worldwide that evaluated vitamin D status among medical students, this study further highlights the problem affecting this student subgroup