New associations of phoretic mites on <Emphasis Type="Italic">Pityokteines curvidens</Emphasis> (Coleoptera,Curculionidae, Scolytinae)

The species composition and abundance of phoretic mites of the bark beetle Pityokteines curvidens caught in pheromone traps were investigated in Croatia. The P. curvidens trapping programs have been in an experimental phase in Croatia since 2004 as a possible monitoring and control system. The trapping program also permits the opportunity to sample phoretic mites found associated with the beetles. Beetles were caught using Curviwit pheromones in Theysohn traps placed in the Litorić region of Croatia. A total of 12 mite species were recovered, including Schizostethus simulatrix, Dendrolaelaps quadrisetus, Histiostoma piceae, H. cf. varia, Paraleius leontonychus, Pleuronectocelaeno barbara, Tarsonemus minimax, Trichouropoda lamellosa, Uroobovella ipidis, Schwiebea sp., Phauloppia lucorum and Dolicheremaeus dorni. Five species, Pl. barbara, Schwiebea sp., H. cf. varia, Ph. lucorum and Do. dorni, are identified for the first time in association with P. curvidens. These findings increase the number of mite species known to be phoretic on P. curvidens from 11 to 16. The present study also increases the number of known mite associates of Pityokteines spp. from 14 to 18.     

Single particle characterization of iron-induced pore-forming alpha-synuclein oligomers

Aggregation of alpha-synuclein is a key event in several neurodegenerative diseases, including Parkinson disease. Recent findings suggest that oligomers represent the principal toxic aggregate species. Using confocal single-molecule fluorescence techniques, such as scanning for intensely fluorescent targets (SIFT) and atomic force microscopy, we monitored alpha-synuclein oligomer formation at the single particle level. Organic solvents were used to trigger aggregation, which resulted in small oligomers ("intermediate I"). Under these conditions, Fe(3+) at low micromolar concentrations dramatically increased aggregation and induced formation of larger oligomers ("intermediate II"). Both oligomer species were on-pathway to amyloid fibrils and could seed amyloid formation. Notably, only Fe(3+)-induced oligomers were SDS-resistant and could form ion-permeable pores in a planar lipid bilayer, which were inhibited by the oligomer-specific A11 antibody. Moreover, baicalein and N'-benzylidene-benzohydrazide derivatives inhibited oligomer formation. Baicalein also inhibited alpha-synuclein-dependent toxicity in neuronal cells. Our results may provide a potential disease mechanism regarding the role of ferric iron and of toxic oligomer species in Parkinson diseases. Moreover, scanning for intensely fluorescent targets allows high throughput screening for aggregation inhibitors and may provide new approaches for drug development and therapy.     

Removing celiac disease-related gluten proteins from bread wheat while retaining technological properties: a study with Chinese Spring deletion lines

Background  

Gluten proteins can induce celiac disease (CD) in genetically susceptible individuals. In CD patients gluten-derived peptides are presented to the immune system, which leads to a CD4⁺ T-cell mediated immune response and inflammation of the small intestine. However, not all gluten proteins contain T-cell stimulatory epitopes. Gluten proteins are encoded by multigene loci present on chromosomes 1 and 6 of the three different genomes of hexaploid bread wheat (Triticum aestivum) (AABBDD).     

Luteinizing hormone and androstendione are independent predictors of ovulation after laparoscopic ovarian drilling: a retrospective cohort study

Background  

Our objective was to investigate luteinizing hormone, follicle-stimulating hormone, testosterone, and androstenedione as predicitve markers for ovulation after laparoscopic ovarian drilling.     

Population structure of the parasitic nematode Anguillicola crassus, an invader of declining North Atlantic eel stocks

Probably half of all animal species exhibit a parasitic lifestyle and numerous parasites have recently expanded their distribution and host ranges due to anthropogenic activities. Here, we report on the population genetic structure of the invasive nematode Anguillicola crassus, a parasite in freshwater eels, which recently spread from Asia to Europe and North America. Samples were collected from the newly colonized naïve host species Anguilla anguilla (Europe) and Anguilla rostrata (North America), and from indigenous Anguilla japonica in Taiwan and Japan. Using seven microsatellite loci and one mitochondrial marker, we show that the parasite's population structure in Europe mirrors the zoogeographic Boreal–Lusitanian break along the English Channel. Both the north-to-south decline of nuclear allelic diversity and the loss of private alleles in the same direction are consistent with a significant isolation-by-distance pattern based on ρ_ST values. In combination with the specific topology of the distance tree among nematode populations, our data suggest that Europe was invaded only once from Taiwan, and that subsequently, genetic diversity was lost due to random drift. On the contrary, the North American sample shares distinct nuclear and mitochondrial signatures with Japanese specimens. We propose that the genetic structure in Europe was shaped by long-range anthropogenic eel host transfers in the north and a single dispersal event into the southwest. The genetically distinct Brittany sample at the edge of the Boreal–Lusitanian boundary is indicative of natural dispersal of fish hosts since recruitment occurs naturally there and invertebrate host dissemination is interrupted due to oceanic currents.     

An archaeal bi-species biofilm formed by <Emphasis Type="Italic">Pyrococcus furiosus</Emphasis> and <Emphasis Type="Italic">Methanopyrus kandleri</Emphasis>

Recently it was shown that Pyrococcus furiosus uses its flagella not only for swimming, but also for establishment of cell-cell connections, and for adhesion to abiotic surfaces. Therefore, it was asked here if P. furiosus might be able to adhere also to biotic surfaces. Since Methanopyrus kandleri can be found in habitats similar to those of P. furiosus (seawater close to the boiling point and anaerobic conditions) it was tested if interactions between both archaea occur. Using a standard medium and a gas phase reduced in H(2) (compared with the optimal gas phase for M. kandleri) we were able to grow both species in a stable coculture. Very interestingly, M. kandleri could adhere to glass under such conditions, but not P. furiosus. This latter archaeum, however, was able to adhere onto M. kandleri cells and onto itself, resulting in structured biofilms on glass. These very often appeared as a bottom layer of M. kandleri cells covered by a multitude of P. furiosus cells. Interactions between P. furiosus and M. kandleri were mediated not only by flagella, but also by direct cell-cell contact.     

Glutathione peroxidase 4 senses and translates oxidative stress into 12/15-lipoxygenase dependent- and AIF-mediated cell death

Oxidative stress in conjunction with glutathione depletion has been linked with various acute and chronic degenerative disorders, yet the molecular mechanisms have remained unclear. In contrast to the belief that oxygen radicals are detrimental to cells and tissues by unspecific oxidation of essential biomolecules, we now demonstrate that oxidative stress is sensed and transduced by glutathione peroxidase 4 (GPx4) into a-yet-unrecognized cell-death pathway. Inducible GPx4 inactivation in mice and cells revealed 12/15-lipoxygenase-derived lipid peroxidation as specific downstream event, triggering apoptosis-inducing factor (AIF)-mediated cell death. Cell death could be entirely prevented either by alpha-tocopherol (alpha-Toc), 12/15-lipoxygenase inhibitors, or siRNA-mediated AIF silencing. Accordingly, 12/15-lipoxygenase-deficient cells were highly resistant to glutathione depletion. Neuron-specific GPx4 depletion caused neurodegeneration in vivo and ex vivo, highlighting the importance of this pathway in neuronal cells. Since oxidative stress is common in the etiology of many human disorders, the identified pathway reveals promising targets for future therapies.     

A new perspective on Listeria monocytogenes evolution

Listeria monocytogenes is a model organism for cellular microbiology and host-pathogen interaction studies and an important food-borne pathogen widespread in the environment, thus representing an attractive model to study the evolution of virulence. The phylogenetic structure of L. monocytogenes was determined by sequencing internal portions of seven housekeeping genes (3,288 nucleotides) in 360 representative isolates. Fifty-eight of the 126 disclosed sequence types were grouped into seven well-demarcated clonal complexes (clones) that comprised almost 75% of clinical isolates. Each clone had a unique or dominant serotype (4b for clones 1, 2 and 4, 1/2b for clones 3 and 5, 1/2a for clone 7, and 1/2c for clone 9), with no association of clones with clinical forms of human listeriosis. Homologous recombination was extremely limited (r/m<1 for nucleotides), implying long-term genetic stability of multilocus genotypes over time. Bayesian analysis based on 438 SNPs recovered the three previously defined lineages, plus one unclassified isolate of mixed ancestry. The phylogenetic distribution of serotypes indicated that serotype 4b evolved once from 1/2b, the likely ancestral serotype of lineage I. Serotype 1/2c derived once from 1/2a, with reference strain EGDe (1/2a) likely representing an intermediate evolutionary state. In contrast to housekeeping genes, the virulence factor internalin (InlA) evolved by localized recombination resulting in a mosaic pattern, with convergent evolution indicative of natural selection towards a truncation of InlA protein. This work provides a reference evolutionary framework for future studies on L. monocytogenes epidemiology, ecology, and virulence.