Trophic Positions of Polyp and Medusa Stages of the Freshwater Jellyfish Based on Stable Isotope Analysis.

When species spread into new regions, competition with native species and predatory-prey relationships play a major role in whether the new species can successfully establish itself in the recipient food web and become invasive. In aquatic habitats, species with a metagenetic life cycle, such as the freshwater jellyfish with benthic polyps and planktonic medusae, have to meet the requirements of two distinct life stages occurring in two habitats with different food webs. Here, we examined the trophic position of both life stages, known to be predatory, and compared their niches with those of putative native competitors using stable isotope analysis.

Cytonuclear diversity and shared mitochondrial haplotypes among Daphnia galeata populations separated by seven thousand kilometres.

Background: The zooplanktonic cladocerans Daphnia, present in a wide range of water bodies, are an important component of freshwater ecosystems. In contrast to their high dispersal capacity through diapausing eggs carried by waterfowl, Daphnia often exhibit strong population genetic differentiation. Here, to test for common patterns in the population genetic structure of a widespread Holarctic species, D.

Daphnia parasite dynamics across multiple Caullerya epidemics indicate selection against common parasite genotypes.

Studies of parasite population dynamics in natural systems are crucial for our understanding of host-parasite coevolutionary processes. Some field studies have reported that host genotype frequencies in natural populations change over time according to parasite-driven negative frequency-dependent selection. However, the temporal patterns of parasite genotypes have rarely been investigated.

Parental and hybrid Daphnia from the D. longispina complex: long-term dynamics in genetic structure and significance of overwintering modes.

In recent decades, hybridization has become a focus of attention because of its role in evolutionary processes. However, little is known about changes in genetic structure within and between parental species and hybrids over time. Here, we studied processes of genetic change in parental species and hybrids from the Daphnia longispina complex (Crustacea, Cladocera) over a period of six years across ten habitats.

Extreme Environments Facilitate Hybrid Superiority - The Story of a Successful Daphnia galeata × longispina Hybrid Clone.

Hybridization within the animal kingdom has long been underestimated. Hybrids have often been considered less fit than their parental species. In the present study, we observed that the Daphnia community of a small lake was dominated by a single D.

Genetic structure of Daphnia galeata populations in Eastern China.

This study presents the first examination of the genetic structure of Daphnia longispina complex populations in Eastern China. Only one species, D. galeata, was present across the eight investigated lakes; as identified by taxon assignment using allelic variation at 15 microsatellite loci.

The Quantification of Representative Sequences pipeline for amplicon sequencing: case study on within-population ITS1 sequence variation in a microparasite infecting Daphnia.

Next generation sequencing (NGS) platforms are replacing traditional molecular biology protocols like cloning and Sanger sequencing. However, accuracy of NGS platforms has rarely been measured when quantifying relative frequencies of genotypes or taxa within populations. Here we developed a new bioinformatic pipeline (QRS) that pools similar sequence variants and estimates their frequencies in NGS data sets from populations or communities.

Population structure of a microparasite infecting Daphnia: spatio-temporal dynamics.

Background: Detailed knowledge of spatial and temporal variation in the genetic population structure of hosts and parasites is required for understanding of host - parasite coevolution. As hot-spots of contemporary coevolution in natural systems are difficult to detect and long-term studies are restricted to few systems, additional population genetic data from various host - parasite systems may provide important insights into the topic. This is particularly true for parasites, as these players have been under-investigated so far due to the lower availability of suitable molecular markers.

Hybridizing Daphnia communities from ten neighbouring lakes: spatio-temporal dynamics, local processes, gene flow and invasiveness.

Background: In natural communities of cyclical parthenogens, rapid response to environmental change is enabled by switching between two reproduction modes. While long periods of asexual reproduction allow some clones to outcompete others, and may result in "clonal erosion", sexual reproduction restores genetic variation in such systems. Moreover, sexual reproduction may result in the formation of interspecific hybrids.

Capturing the population structure of microparasites: using ITS-sequence data and a pooled DNA approach.

The internal transcribed spacer (ITS) region of nuclear ribosomal DNA is a common marker not only for the molecular identification of different taxa and strains, but also for the analysis of population structure of wild microparasite communities. Importantly, the multicopy nature of this region allows the amplification of low-quantity samples of the target DNA, a common problem in studies on unicellular, unculturable microparasites. We analysed ITS sequences from the protozoan parasite Caullerya mesnili (class Ichthyosporea) infecting waterflea (Daphnia) hosts, across several host population samples.

Transmission mode affects the population genetic structure of Daphnia parasites.

Parasite life cycle variation can shape parasite evolution, by predisposing them towards different population genetic structures. We compared the population genetic structure of two co-occurring parasite species of Daphnia, to collect evidence for their expected transmission modes. The ichthyosporean Caullerya mesnili has a direct life cycle, whereas the microsporidian Berwaldia schaefernai is hypothesized to require passage through a secondary host.

Clonal diversity, clonal persistence and rapid taxon replacement in natural populations of species and hybrids of the Daphnia longispina complex.

Hybridization is common among cyclical parthenogens, especially in zooplankton species assemblages of the genus Daphnia. To explore hybridization dynamics and the extent of clonal diversity in the Daphnia longispina complex, we analysed population structure in eight permanent lakes. Based on 15 microsatellite loci, three major taxonomic units emerged: two species, D.

Molecular identification and hidden diversity of novel Daphnia parasites from European lakes.

Parasites play important roles in local population dynamics and genetic structure. However, due to insufficient diagnostic tools, detailed host-parasite interactions may remain concealed by hidden parasite diversity in natural systems. Microscopic examination of 19 European lake Daphnia populations revealed the presence of three groups of parasites: fungi, microsporidia, and oomycetes.

Dynamic reticulate evolution in a Daphnia multispecies complex.

Recent genomic data suggest that the role of hybridization in evolution might be more important than previously assumed. Here, we examine species-specific differentiation and signatures of reticulation in a multi-species complex of the crustacean genus Daphnia. We did a combined examination of mtDNA, allozymes and ITS1 (a part of the nuclear ribosomal DNA) in the Daphnia longispina group.

Inorganic membranes for hydrogen production and purification: a critical review and perspective.

Hydrogen as a high-quality and clean energy carrier has attracted renewed and ever-increasing attention around the world in recent years, mainly due to developments in fuel cells and environmental pressures including climate change issues. In thermochemical processes for hydrogen production from fossil fuels, separation and purification is a critical technology. Where water-gas shift reaction is involved for converting the carbon monoxide to hydrogen, membrane reactors show great promises for shifting the equilibrium.

[Results of wavefront-guided LASIK].

Background: Wavefront-guided LASIK procedures provide patients with customized corneal treatments. The computer ablation profiles correct both spherical and/or cylindrical errors of refraction and aberrations up to the fifth order.

Methods: We performed wavefront-guided LASIK treatments on 62 patients using the Keracor 217 Z.

[Corneal wound healing after hyperopic PRK and LASIK].

Background: The purpose of this study was to investigate the influence of different postoperative treatments on the wound healing reaction in the anterior stroma after PRK and in the interface area after LASIK.

Methods: Seventy-two corneal buttons of refractively treated rabbit eyes underwent different postoperative eyedrop regimens with antibiotics and/or steroids or additional UV-B irradiation. Morphological and immunohistological investigations were performed 6 months postoperatively by light and transmission electron microscopy.

Hydrophobicity of templated silica xerogels for molecular sieving applications.

Silica xerogels were prepared by a sol-gel process catalyzed by acid with tetraethylorthosilicate, and using an organic covalent ligand template (methyltriethoxysilane) or a noncovalent template C6 surfactant (triethylhexylammonium bromide). The influence of hydrotreatment on the structure of templated xerogels is examined in terms of surface area, micropore volume, average pore size, and pore size distribution, and compared against a blank xerogel (nontemplated). The role of surface functional groups was evaluated using 29Si nuclear magnetic resonance.

[Aberrometry due dilated pupils--Which mydriatic should be used?].

Background: For a wavefront-based LASIK procedure aberrometric measurements are necessary via a dilated pupil. The more dilated the pupil is the more aberrations can be identified. There are different mydriatic eyedrops used to dilate the pupil.

[Recurrent corneal erosion after mechanical trauma. Results of transepithelial phototherapeutic keratectomy].

Background: Recurrent corneal erosion is a common clinical disorder characterised by repeated spontaneous breakdown of the corneal epithelium. The pathomechanism is due to abnormalities of the adhesion complex between the corneal epithelium and the stroma. In addition to local medical treatment, bandage lenses, debridement and anterior stromal puncture, patients can also be treated by excimer laser phototherapeutic keratectomy.

Short-term visual rehabilitation after LASIK.

Purpose: To determine the early course of visual recovery after LASIK for myopia.

Methods: In eight eyes visual acuity, both uncorrected and corrected, objective refraction, topography and contrast sensitivity were measured six times during the first day, twice daily for two days and after 1 week.

Results: Patients experienced considerable variability in achieving best corrected visual acuity.

[Specular microscopy follow-up of endophthalmitis after cataract operation].

Introduction: Since the first reports of specular microscopic photographs in vivo of the corneal endothelium, endophthalmitis is said to damage endothelial cells irreversibly.

Patients And Method: We controlled 29 eyes 1 to 10 years after endophthalmitis following cataract surgery using specular microscopy. We tried to find out, if endophthalmitis leads to significant endothelial damage and we wanted to describe the in-vivo-cytological follow-up of the implanted lenses.

[Spontaneous hematocornea after keratitis of various etiology].

Background: Corneal blood staining may occur as a serious complication of persisting hyphema. In our two cases the corneal blood staining is a result of direct bleeding in the corneal stroma.

History And Signs: A female patient presented with a corneal blood staining through rupture of reopened vessels in interstitial keratitis of congenital syphilis after physical effort with high blood pressure.