Paläogenetik der Pest

Paleogenetics of the plague Plague has been part of our history since ancient times. Introduced again and again to Europe over centuries, the 'pestilences' killed millions of people before disappearing from the continent in 19^th Century. In the Middle Ages, bacteria were unknown and often the transmission routes of plague remained unrecognized. Plague was considered as a punishment by God disseminated by Miasma. With modern methods, microbiologists and palaeogenetists have now successfully shown that all the three historical recognized plague pandemics indeed were caused by the bacterium Yersinia pestis. In addition, important information has been obtained about the evolution of the bacterium and its origin. New data from ongoing studies on victims of the past epidemics help to shed new light on the past and perhaps even on the present of plague.     

Plant mitochondria use two pathways for the biogenesis of tRNAHis

All tRNA^His possess an essential extra G_–1 guanosine residue at their 5′ end. In eukaryotes after standard processing by RNase P, G_–1 is added by a tRNA^His guanylyl transferase. In prokaryotes, G_–1 is genome-encoded and retained during maturation. In plant mitochondria, although trnH genes possess a G_–1 we find here that both maturation pathways can be used. Indeed, tRNA^His with or without a G_–1 are found in a plant mitochondrial tRNA fraction. Furthermore, a recombinant Arabidopsis mitochondrial RNase P can cleave tRNA^His precursors at both positions G₊₁ and G_–1. The G_–1 is essential for recognition by plant mitochondrial histidyl-tRNA synthetase. Whether, as shown in prokaryotes and eukaryotes, the presence of uncharged tRNA^His without G_–1 has a function or not in plant mitochondrial gene regulation is an open question. We find that when a mutated version of a plant mitochondrial trnH gene containing no encoded extra G is introduced and expressed into isolated potato mitochondria, mature tRNA^His with a G_–1 are recovered. This shows that a previously unreported tRNA^His guanylyltransferase activity is present in plant mitochondria.     

A prospective, randomised, controlled clinical study on the assessment of tolerability and of clinical efficacy of Merional (hMG-IBSA) administered subcutaneously versus Merional administered intramuscularly in women undergoing multifollicular ovarian stimulation in an ART programme (IVF)

Background  

Multifollicular ovarian stimulation (MOS) is widely used in IVF and the compliance to treatment is deeply influenced by the tolerability of the medication(s) used and by the ease of self-administration. This prospective, controlled, randomised, parallel group open label, multicenter, phase III, equivalence study has been aimed to compare the clinical effectiveness (in terms of oocytes obtained) and tolerability of subcutaneous (s.c.) self-administered versus classical intramuscular (i.m.) injections of Merional, a new highly-purified hMG preparation.     

Effects of sucrose on the internal dynamics of azurin

Sucrose is a natural osmolyte accumulated in cells of organisms as they adapt to environmental stresses. In vitro, sucrose increases protein stability and forces partially unfolded structures to refold. Its effects on the native fold structure and dynamics are not fully established. This study, utilizing Trp phosphorescence spectroscopy, examined the influence of molar concentrations of sucrose on the flexibility of metal-free azurin from Pseudomonas aeruginosa. In addition, by means of specific mutants of the test protein, namely I7S, F110S, and C3A/C26A, that altered its thermodynamic stability, its intrinsic flexibility, and the extent of internal hydration, this investigation sought to identify possible correlations between these features of protein structure and the influence of the osmolyte on protein dynamics. Alterations of structural fluctuations were assessed by both the intrinsic phosphorescence lifetime (tau), which reports on local structure about the triplet probe, and the acrylamide bimolecular quenching rate constant (k(q)) that is a measure of the average acrylamide diffusion coefficient through the macromolecule. From the modulation of tau and k(q) across a wide temperature range and up to a concentration of 2M sucrose, it is concluded that sucrose attenuates structural fluctuations principally when macromolecules are internally hydrated and thermally expanded. Preliminary tests with trehalose and xylitol suggest that the effects of sucrose are general of the polyol class of osmolytes.     

Integrins, muscle agrin and sarcoglycans during muscular inactivity conditions: an immunohistochemical study

Sarcoglycans are transmembrane proteins that seem to be functionally and pathologically as important as dystrophin. Sarcoglycans cluster together to form a complex, which is localized in the cell membrane of skeletal, cardiac, and smooth muscle. It has been proposed that the dystrophin-glycoprotein complex (DGC) links the actin cytoskeleton with the extracellular matrix and the proper maintenance of this connection is thought to be crucial to the mechanical stability of the sarcolemma. The integrins are a family of heterodimeric cell surface receptors which play a crucial role in cell adhesion including cell-matrix and intracellular interactions and therefore are involved in various biological phenomena, including cell migration, and differentiation tissue repair. Sarcoglycans and integrins play a mechanical and signaling role stabilizing the systems during cycles of contraction and relaxation. Several studies suggested the possibility that integrins might play a role in muscle agrin signalling. On these basis, we performed an immunohistochemical analyzing sarcoglycans, integrins and agrin, on human skeletal muscle affected by sensitive-motor polyneuropathy, in order to better define the correlation between these proteins and neurogenic atrophy due to peripheral neuropathy. Our results showed the existence of a cascade mechanism which provoke a loss of regulatory effects of muscle activity on costameres, due to loss of muscle and neural agrin. This cascade mechanism could determine a quantitative modification of transmembrane receptors and loss of alpha7B could be replaced and reinforced by enhanced expression of the alpha7A integrin to restore muscle fiber viability. Second, it is possible that the reduced cycles of contraction and relaxation of muscle fibers, during muscular atrophy, provoke a loss of mechanical stresses transmitted over cell surface receptors that physically couple the cytoskeleton to extracellular matrix. Consequently, these mechanical changes could determine modifications of chemical signals through variations of pathway structural integrins, and alpha7A could replace alpha7B.     

Reproductive cycle and trophic ecology in deep versus shallow populations of the Mediterranean gorgonian Eunicella singularis (Cap de Creus,northwestern Mediterranean Sea)

Coral Reefs - The annual gonad development of a shallow (20 m depth) population of the Mediterranean gorgonian Eunicella singularis was found to be closely synchronized with that of a deep...