Selection of HLA compatible donors for patients with HLA antibodies

A strain of 1,507 typised donors enables 15.97 average donors to be selected for a thrombocyte transfusion in one of 75 patients selected at random with HLA antibodies being previously determined (1 to 66 donors per patient). HLA compatible donors were found for 72 patients (97.33 per cent). More than 5 HLA compatible donors could be found for 58 patients. The high number of compatible donors is based on the fact that among 1,507 donors there were 156 HLA homozygotes and 556 donors with 3 HLA-A or B-antigens respectively. Compatibility in the ABO-system was not taken into account.     

Internal lipid synthesis and vesicle growth as a step toward self-reproduction of the minimal cell

One of the major properties of the semi-synthetic minimal cell, as a model for early living cells, is the ability to self-reproduce itself, and the reproduction of the boundary layer or vesicle compartment is part of this process. A minimal bio-molecular mechanism based on the activity of one single enzyme, the FAS-B (Fatty Acid Synthase) Type I enzyme from Brevibacterium ammoniagenes, is encapsulated in 1-palmitoyl-2oleoyl-sn-glycero-3-phosphatidylcholine (POPC) liposomes to control lipid synthesis. Consequently molecules of palmitic acid released from the FAS catalysis, within the internal lumen, move toward the membrane compartment and become incorporated into the phospholipid bilayer. As a result the vesicle membranes change in lipid composition and liposome growth can be monitored. Here we report the first experiments showing vesicles growth by catalysis of one enzyme only that produces cell boundary from within. This is the prototype of the simplest autopoietic minimal cell.     

Identifying essential genes in bacterial metabolic networks with machine learning methods

Background  

Identifying essential genes in bacteria supports to identify potential drug targets and an understanding of minimal requirements for a synthetic cell. However, experimentally assaying the essentiality of their coding genes is resource intensive and not feasible for all bacterial organisms, in particular if they are infective.     

Trees on networks: resolving statistical patterns of phylogenetic similarities among interacting proteins

Background  

Phylogenies capture the evolutionary ancestry linking extant species. Correlations and similarities among a set of species are mediated by and need to be understood in terms of the phylogenic tree. In a similar way it has been argued that biological networks also induce correlations among sets of interacting genes or their protein products.     

Membrane microheterogeneity: Förster resonance energy transfer characterization of lateral membrane domains

Lateral membrane heterogeneity, in the form of lipid rafts and microdomains, is currently implicated in cell processes including signal transduction, endocytosis, and cholesterol trafficking. Various biophysical techniques have been used to detect and characterize lateral membrane domains. Among these, Förster resonance energy transfer (FRET) has the crucial advantage of being sensitive to domain sizes smaller than 50-100 nm, below the resolution of optical microscopy but, apparently, similar to those of rafts in cell membranes. In the last decade, several formalisms for the analysis of FRET in heterogeneous membrane systems have been derived and applied to the study of microdomains. They are critically described and illustrated here.     

Littoral diatoms as indicators for the eutrophication of shallow lakes

The littoral zone of shallow water bodies in the Czech Republic has been studied quite consistently at several fishponds. The use of algae, especially diatoms, for the monitoring of the state of lotic freshwater also has a long tradition. The main objective of the presented paper is to validate the feasibility of the use of littoral periphyton comunities for the biomonitoring of standing waters. At the investigated sites, littoral periphytic diatoms were studied together with selected enviromental variables (pH, conductivity, nutrients – especially total phosphorus) on three types of natural substrates (epilithon, epiphyton, epipelon). The evaluation of the diatom community was performed on the basis of the checklists of algal indicator species published by authors from the Czech Republic, Austria and the Netherlands. The data were subjected to statistical software NCCS 2000 (GLM Anova and ``Ward's minimum'' variance cluster analysis). Littoral periphytic diatoms appear to be good indicators of the fishpond water quality. The selected substrates show non-significant differences therefore the average values from all substrates were used. The best indicatory system for evaluation of Czech fishponds was van Dam's index.

     

Dispersal vs. vicariance in the Mediterranean: historical biogeography of the Palearctic Pachydeminae (Coleoptera, Scarabaeoidea)

Aim The geological evolution of the Mediterranean region is largely the result of the Tertiary collision of the African and Eurasian Plates, but also a mosaic of migrating island arcs, fragmenting tectonic belts, and extending back‐arc basins. Such complex paleogeography has resulted in a ‘reticulate’ biogeographical history, in which Mediterranean biotas repeatedly fragmented and merged as dispersal barriers appeared and disappeared through time. In this study, dispersal‐vicariance analysis (DIVA) is used to assess the relative role played by dispersal and vicariance in shaping distribution patterns in the beetle subfamily Pachydeminae Reitter, 1902 (Scarabaeoidea), an example of east–west Mediterranean disjunction. Location The Mediterranean region, including North Africa, the western Mediterranean, Balkans–Anatolia, Middle East, Caucasus, the Iranian Plateau, and Central Asia. Methods A phylogenetic hypothesis of the Palearctic genera of Pachydeminae in conjunction with distributional data was analysed using DIVA. This method reconstructs the ancestral distribution in a given phylogeny based on the vicariance model, while allowing dispersal and extinction to occur. Unlike other methods, DIVA does not enforce area relationships to conform to a hierarchical ‘area cladogram’, so it can be used to reconstruct ‘reticulate’ biogeographical scenarios. Results Optimal reconstructions, requiring 23 dispersal events, suggest that the ancestor of Pachydeminae was originally present in the south‐east Mediterranean region. Basal splitting within the subfamily was caused by vicariance events related to the late Tertiary collision of the African microplates Apulia and Arabia with Eurasia, and the resultant arise of successive dispersal barriers (e.g. the Red Sea, the Zagros Mountains). Subsequent diversification in Pachydeminae involved multiple speciation events within the Middle East and Iran–Afghanistan regions, which gave rise to the least speciose genera of Pachydeminae (e.g. Otoclinius Brenske, 1896). Finally, the presence of Pachydeminae in the western Mediterranean region seems to be the result of a recent dispersal event. The ancestor of the Iberian genera Ceramida Baraud, 1987 and Elaphocera Gené, 1836 probably dispersed from the Middle East to the Iberian Peninsula across North Africa and the Gibraltar Strait during the ‘Messinian salinity crisis’ at the end of the Miocene. Main conclusions Although the basal diversification of Pachydeminae around the Mediterranean appears to be related to vicariance events linked to the geological formation of the Mediterranean Basin, dispersal has also played a very important role. Nearly 38% of the speciation events in the phylogeny resulted from dispersal to a new area followed by allopatric speciation between lineages. Relationships between western and eastern Mediterranean disjuncts are usually explained by dispersal through Central Europe. The biogeographical history of the Pachydeminae corroborates other biogeographical studies that consider North Africa to be an alternative dispersal route by which Mediterranean taxa could have achieved circum‐Mediterranean distributions.