The genus Polyarthra in Lake Peipsi

In Lake Peipsi (Estonia) Polyarthra species often dominate the rotifer community, and are represented by 6 species: Polyarthra dolichoptera Idelson, P. longiremis Carlin, P. luminosa Kutikova, P. major Burckhardt, P. remata Skorikov, P. vulgaris Carlin. The highest diversity occurs in August–September, with P. remata and P. luminosa most abundant. Morphometric data including measurements of body, fins and various types of eggs are given. The seasonal development of the different species and their life cycles are considered.     

The role of endocytosis on the uptake kinetics of luciferin-conjugated cell-penetrating peptides

Cell-penetrating peptides (CPPs) are short cationic/amphipathic peptides that can be used to deliver a variety of cargos into cells. However, it is still debated which routes CPPs employ to gain access to intracellular compartments. To assess this, most previously conducted studies have relied on information which is gained by using fluorescently labeled CPPs. More relevant information whether the internalized conjugates are biologically available has been gathered using end-point assays with biological readouts. Uptake kinetic studies have shed even more light on the matter because the arbitrary choice of end-point might have profound effect how the results could be interpreted. To elucidate uptake mechanisms of CPPs, here we have used a bioluminescence based assay to measure cytosolic delivery kinetics of luciferin-CPP conjugates in the presence of endocytosis inhibitors. The results suggest that these conjugates are delivered into cytosol mainly via macropinocytosis; clathrin-mediated endocytosis and caveolae/lipid raft dependent endocytosis are involved in a smaller extent. Furthermore, we demonstrate how the involved endocytic routes and internalization kinetic profiles can depend on conjugate concentration in case of certain peptides, but not in case of others. The employed internalization route, however, likely dictates the intracellular fate and subsequent trafficking of internalized ligands, therefore emphasizing the importance of our novel findings for delivery vector development.     

Proteome analysis of chemically induced mouse liver tumors with different genotype

Mouse liver tumors frequently harbor mutations in Ha-ras, B-raf, or Ctnnb1 (encoding beta-catenin). We conducted a proteome analysis with protein extracts from normal mouse liver and from liver tumors which were induced by a single injection of N-nitrosodiethylamine (DEN) as initiator followed by multiple injections of two different polychlorinated biphenyls (PCBs) as tumor promoters, or corn oil as a control. Liver tumors were stratified into two classes: they were either mutated in Ctnnb1 and positive for the marker glutamine synthetase (GS(+)), or they lacked Ctnnb1 mutations and were therefore GS-negative (GS(-)). Proteome analysis by 2-DE and MS revealed 98 significantly deregulated proteins, 44 in GS(+) and 54 in GS(-) tumors. Twelve of these proteins showed expression changes in both tumor types, but only seven of them were deregulated in the same direction. Several of the identified enzymes could be assigned to fundamental metabolic or other cellular pathways with characteristically different alterations in GS(+) and GS(-) tumors such as ammonia and amino acid turnover, cellular energy supply, and calcium homeostasis. Our data suggest that GS(+) and GS(-) tumor cells show a completely different biology and use divergent evolutionary strategies to gain a selective advantage over normal hepatocytes.     

Transfection of Infectious RNA and DNA/RNA Layered Vectors of Semliki Forest Virus by the Cell-Penetrating Peptide Based Reagent PepFect6

Viral vectors have a wide variety of applications ranging from fundamental studies of viruses to therapeutics. Recombinant viral vectors are usually constructed using methods of reverse genetics to obtain the genetic material of the viral vector. The physicochemical properties of DNA and RNA make them unable to access cells by themselves, and they require assistance to achieve intracellular delivery. Non-viral delivery vectors can be used for this purpose if they enable efficient intracellular delivery without interfering with the viral life cycle. In this report, we utilize Semliki Forest virus (genus alphavirus) based RNA and DNA vectors to study the transfection efficiency of the non-viral cell-penetrating peptide-based delivery vector PepFect6 in comparison with that of the cationic liposome-based Lipofectamine 2000, and assess their impact on viral replication. The optimal conditions for transfection were determined for both reagents. These results demonstrate, for the first time, the ability of PepFect6 to transport large (13-19 kbp) constructs across the cell membrane. Curiously, DNA molecules delivered using the PepFect6 reagent were found to be transported to the cell nucleus approximately 1.5 hours later than DNA molecules delivered using the Lipofectamine 2000 reagent. Finally, although both PepFect6 and Lipofectamine 2000 reagents can be used for alphavirus research, PepFect6 is preferred because it does not induce changes in the normal cellular phenotype and it does not affect the normal replication-infection cycle of viruses in previously transfected cells.     

Dilation of human atria: Increased diffusion restrictions for ADP,overexpression of hexokinase 2 and its coupling to oxidative phosphorylation in cardiomyocytes

Cardiac energy metabolism with emphasis on mitochondria was addressed in atrial tissue from patients with overload-induced atrial dilation. Structural remodeling of dilated (D) atria manifested as intracellular accumulation of fibrillar aggregates, lipofuscin, signs of myolysis and autophagy. Despite impaired complex I dependent respiration and increased diffusion restriction for ADP, no changes regarding adenylate and creatine kinase occurred. We observed 7-fold overexpression of HK2 gene in D atria with concomitant 2-fold greater activation of mitochondrial oxygen consumption by glucose, which might represent an adaption to increased energy requirements and impaired mitochondrial function by effectively joining glycolysis and oxidative phosphorylation.     

Successful reproduction and pheromone production by the spruce bark beetle in evolutionary naïve spruce hosts with familiar terpenoid defences

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Tagging quantitative trait loci for maturity-corrected late blight resistance in tetraploid potato with PCR-based candidate gene markers

Late blight caused by the oomycete Phytophthora infestans is the economically most important and destructive disease in potato cultivation. Quantitative resistance to late blight available in tetraploid cultivars is correlated with late maturity in temperate climates, which is an undesirable characteristic. A total of 30 DNA-based markers known to be linked to loci for pathogen resistance in diploid potato were selected and tested as polymerase chain reaction-based markers for linkage with quantitative trait loci (QTL) for late blight resistance and plant maturity in two half-sib families of tetraploid potatoes. Most markers originated from within or were physically closely linked to candidate genes for quantitative resistance factors. The families were repeatedly evaluated in the field for quantitative resistance to late blight and maturity. Resistance was corrected for the maturity effect. Nine of eleven different map segments tagged by the markers harbored QTL affecting maturity-corrected resistance. Interactions were found between unlinked resistance QTL, providing testable strategies for marker-assisted selection in tetraploid potato. Based on the linkage observed between QTL for resistance and plant maturity and based on the genetic interactions observed between candidate genes tagging resistance QTL, we discuss models for the molecular basis of quantitative resistance and maturity.     

Potentilla L. sect.Rivales Wolf and related taxa in the Baltic states

Morphological variation ofPotentilla norvegica L.,P. heidenreichii Zimmeter andP. supina L. usually treated within the sectionRivales Wolf,P. recta L. (sect.Rectae Wolf),P. canescens Bess.,P. argentea L. s.l.,P. collina Wibel (sect.Argenteae Wolf) andP. goldbachii Rupr. (sect.Chrysanthae Wolf) was studied using multivariate statistical methods. According to k-means clustering,P. canescens stands closer toP. heidenreichii of the sect.Rivales than toP. argentea. P. collina, the other representative of sect.Argenteae, is not connected withP. canescens at all. Therefore,P. canescens should belong to sect.Rivales and not to sect.Argenteae. InPotentilla argentea s.l.,P. impolita Wahlenb.,P. argentea L. var.argentea, var.decumbens (Jord.)Lehm., var.demissa (Jord.) Lehm., var.grandiceps (Zimmeter) Rouy etE.G. Camus and var.tenerrima (Velen.) Wolf were identified.P. impolita specimens did not cluster out into a separate cluster as didP. collina, P. canescens andP. heidenreichii, but formed mixed clusters with different varieties ofP. argentea s.str. Therefore,P. impolita is not worthy of the rank of species and evidently not even that of subspecies, and should be treated as a variety—P. argentea var.incanescens (Opiz) Focke.     

Molecular cloning of the potato Gro1-4 gene conferring resistance to pathotype Ro1 of the root cyst nematode Globodera rostochiensis, based on a candidate gene approach

The endoparasitic root cyst nematode Globodera rostochiensis causes considerable damage in potato cultivation. In the past, major genes for nematode resistance have been introgressed from related potato species into cultivars. Elucidating the molecular basis of resistance will contribute to the understanding of nematode-plant interactions and assist in breeding nematode-resistant cultivars. The Gro1 resistance locus to G. rostochiensis on potato chromosome VII co-localized with a resistance-gene-like (RGL) DNA marker. This marker was used to isolate from genomic libraries 15 members of a closely related candidate gene family. Analysis of inheritance, linkage mapping, and sequencing reduced the number of candidate genes to three. Complementation analysis by stable potato transformation showed that the gene Gro1-4 conferred resistance to G. rostochiensis pathotype Ro1. Gro1-4 encodes a protein of 1136 amino acids that contains Toll-interleukin 1 receptor (TIR), nucleotide-binding (NB), leucine-rich repeat (LRR) homology domains and a C-terminal domain with unknown function. The deduced Gro1-4 protein differed by 29 amino acid changes from susceptible members of the Gro1 gene family. Sequence characterization of 13 members of the Gro1 gene family revealed putative regulatory elements and a variable microsatellite in the promoter region, insertion of a retrotransposon-like element in the first intron, and a stop codon in the NB coding region of some genes. Sequence analysis of RT-PCR products showed that Gro1-4 is expressed, among other members of the family including putative pseudogenes, in non-infected roots of nematode-resistant plants. RT-PCR also demonstrated that members of the Gro1 gene family are expressed in most potato tissues.