Alien aquatic vascular plants in Hungary (Pannonian ecoregion): Historical aspects,data set and trends

Estimating the extent of biological invasions is critical in predicting the effect of exotic species. We investigated the occurrence and number of alien freshwater plants and give information on the composition of alien aquatic flora, their trend in time, invasion pathway, and their invasive character.     

Taxonomic,phylogenetic and ecological diversity of Niphargus (Amphipoda: Crustacea) in the Hölloch cave system (Switzerland)

Groundwater belongs to the spatially most extensive, but least explored freshwater systems. On a global scale, the species richness of several subterranean invertebrate taxa parallels species richness found in surface waters, while on a local scale species richness hardly exceeds 20 species. This results in a high contribution of groundwater ecosystems to regional β- and γ-diversity, and to a smaller degree to α-diversity, and deserves focused attention. In general, more species are to be found in large cave systems. The second largest cave system in Europe is Hölloch in Switzerland. In this paper we revised the taxonomic, phylogenetic and ecological diversity of the amphipod community in the Hölloch cave system. While previous records listed five geographically widespread species of the genus Niphargus for this cave system, we could not confirm the presence of any of those species, but rather found three highly distinct species new to science. In this paper we describe Niphargus styx sp. nov., Niphargus murimali sp. nov., and Niphargus muotae sp. nov., and suggest that previous records from that cave were probably misidentifications. Although amphipod species richness in this cave system seems to be lower than previously thought in terms of absolute numbers, the cave retained its regional and international importance in terms of nature conservation for multiple reasons. First, all newly described species are probably endemic to this cave system. Second, they are phylogenetically distantly related and exhibit moderate to high phylogenetic diversity. Third, the species, as inferred from their functional morphology, are also ecologically highly divergent. Based on geographic distribution of their nearest relatives, we hypothesize that the cave system was most likely independently colonized from North, West and South and that the pre-adapted ancestors occupied different ecological niches within the system.

http://zoobank.org/urn:lsid:zoobank.org:pub:A19309E5-C06B-4844-A4D8-7571F05F25C9     

Lipid Transport between the Endoplasmic Reticulum and Mitochondria

Mitochondria are partially autonomous organelles that depend on the import of certain proteins and lipids to maintain cell survival and membrane formation. Although phosphatidylglycerol, cardiolipin, and phosphatidylethanolamine are synthesized by mitochondrial enzymes, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, and sterols need to be imported from other organelles. The origin of most lipids imported into mitochondria is the endoplasmic reticulum, which requires interaction of these two subcellular compartments. Recently, protein complexes that are involved in membrane contact between endoplasmic reticulum and mitochondria were identified, but their role in lipid transport is still unclear. In the present review, we describe components involved in lipid translocation between the endoplasmic reticulum and mitochondria and discuss functional as well as regulatory aspects that are important for lipid homeostasis.Biological membranes are major structural components of all cell types. They protect the cell from external influences, organize the interior in distinct compartments and allow balanced flux of components. Besides their specific proteome, organelles exhibit unique lipid compositions, which influence their shape, physical properties, and function. Major lipid classes found in biological membranes are phospholipids, sterols, and sphingolipids.The major “lipid factory” within the cell is the endoplasmic reticulum (ER). It is able to synthesize the bulk of structural phospholipids, sterols, and storage lipids such as triacylglycerols and steryl esters (van Meer et al. 2008). Furthermore, initial steps of ceramide synthesis occur in the ER providing precursors for the formation of complex sphingolipids in other organelles (Futerman 2006). Besides the export of ceramides, the ER supplies a large portion of lipids to other organelles, which cannot produce their own lipids or have a limited capacity to do so. Organelle interaction and transport of lipids require specific carrier proteins, membrane contact sites, tethering complexes, and/or vesicle flux. These processes are highly important for the maintenance of cell structure and survival but are still a matter of dispute. Most prominent organelle interaction partners are the ER and mitochondria. A subfraction of the ER named mitochondria-associated membrane (MAM) (Vance 1990) was described to be involved in lipid translocation to mitochondria. MAM is part of the ER network, which was shown to be in contact or close proximity to the outer mitochondrial membrane (OMM). Contact sites between MAM and mitochondria were assumed to facilitate exchange of components between the two compartments. Interestingly, MAM harbor a number of lipid synthesizing enzymes (Gaigg et al. 1994). Recently, molecular components governing membrane contact between the two organelles were identified (Dolman et al. 2005; Csordás et al. 2006; de Brito and Scorrano 2008; Kornmann et al. 2009; Friedman et al. 2010; Lavieu et al. 2010), although the specific role of these components in lipid translocation is not yet clear.     

Morphology, biophysical properties and protein-mediated fusion of archaeosomes

As variance from standard phospholipids of eubacteria and eukaryotes, archaebacterial diether phospholipids contain branched alcohol chains (phytanol) linked to glycerol exclusively with ether bonds. Giant vesicles (GVs) constituted of different species of archaebacterial diether phospholipids and glycolipids (archaeosomes) were prepared by electroformation and observed under a phase contrast and/or fluorescence microscope. Archaebacterial lipids and different mixtures of archaebacterial and standard lipids formed GVs which were analysed for size, yield and ability to adhere to each other due to the mediating effects of certain plasma proteins. GVs constituted of different proportions of archaeal or standard phosphatidylcholine were compared. In nonarchaebacterial GVs (in form of multilamellar lipid vesicles, MLVs) the main transition was detected at T_m = 34. 2°C with an enthalpy of ΔH = 0.68 kcal/mol, whereas in archaebacterial GVs (MLVs) we did not observe the main phase transition in the range between 10 and 70°C. GVs constituted of archaebacterial lipids were subject to attractive interaction mediated by beta 2 glycoprotein I and by heparin. The adhesion constant of beta 2 glycoprotein I – mediated adhesion determined from adhesion angle between adhered GVs was in the range of 10⁻⁸ J/m². In the course of protein mediated adhesion, lateral segregation of the membrane components and presence of thin tubular membranous structures were observed. The ability of archaebacterial diether lipids to combine with standard lipids in bilayers and their compatibility with adhesion-mediating molecules offer further evidence that archaebacterial lipids are appropriate for the design of drug carriers.     

Physico-chemical modeling of the role of free radicals in photo-dynamic therapy. I. Utilization of quantum yield data of singlet oxygen formation for the study of the interaction between excited photosensitizer and stable free radicals.

The measurement of the relative quantum yield of singlet oxygen formation, a simple process without tedious sample deoxygenation, is shown to furnish data on the interaction of the excited photosensitizer with any additive (in this case stable free radicals) given to the sample. The rate constants derived from such measurements are in good agreement with direct determination of the corresponding values.     

Host plant‐related genomic differentiation in the European cherry fruit fly,Rhagoletis cerasi

Elucidating the mechanisms and conditions facilitating the formation of biodiversity are central topics in evolutionary biology. A growing number of studies imply that divergent ecological selection may often play a critical role in speciation by counteracting the homogenising effects of gene flow. Several examples involve phytophagous insects, where divergent selection pressures associated with host plant shifts may generate reproductive isolation, promoting speciation. Here, we use ddRADseq to assess the population structure and to test for host‐related genomic differentiation in the European cherry fruit fly, Rhagoletis cerasi (L., 1758) (Diptera: Tephritidae). This tephritid is distributed throughout Europe and western Asia, and has adapted to two different genera of host plants, Prunus spp. (cherries) and Lonicera spp. (honeysuckle). Our data imply that geographic distance and geomorphic barriers serve as the primary factors shaping genetic population structure across the species range. Locally, however, flies genetically cluster according to host plant, with consistent allele frequency differences displayed by a subset of loci between Prunus and Lonicera flies across four sites surveyed in Germany and Norway. These 17 loci display significantly higher F_ST values between host plants than others. They also showed high levels of linkage disequilibrium within and between Prunus and Lonicera flies, supporting host‐related selection and reduced gene flow. Our findings support the existence of sympatric host races in R. cerasi embedded within broader patterns of geographic variation in the fly, similar to the related apple maggot, Rhagoletis pomonella, in North America.