Genetic monitoring and effects of stocking practices on small <Emphasis Type="Italic">Cyprinus carpio</Emphasis> populations

The ability to detect genetic differences both in space and time is crucial for conserving genetic variation. It can reveal genetic diversity and genetic composition changes of declining native populations that are supported through stocking with captive bred individuals. The present study was designed to analyse the temporal stability of a declining common carp (Cyprinus carpio) population from Lake Volvi (North Greece). Polymorphism was evaluated using seven microsatellite loci at two sampling time points (separated by 12 years). The genetic variability of four additional populations (from two rivers and two lakes) in Northern Greece was also investigated for comparison. Heterozygosity values (0.692–0.868) and allelic richness (8.530–11.148) were high for all studied populations and comparable to other European populations. However, the analysis of temporal common carp samples from Lake Volvi revealed a significant change in their genetic composition and admixture analysis demonstrated significant introgression of stocked individuals into the native population. Both temporal and point estimate methods revealed low effective size (Ne = 61–171.3) for this population, possibly a result of an ancient genetic bottleneck that led to population decline and/or recent anthropogenic interventions. This low Ne has rendered the native population vulnerable to alteration of its genetic composition. Our study demonstrates that enhancement programs should be applied cautiously, especially for small populations. Moreover, it underlines the need for temporal analyses, which may contribute to the evaluation of previous management policies and to future decision making.     

Estimating lagoonal biodiversity in Greece: comparison of rapid assessment techniques

An attempt is made to compare the results of different rapid biodiversity assessment techniques at the pan-Mediterranean, sectorial and local levels. A uniform multivariate pattern exists at the pan-Mediterranean and national (sectorial) levels: lagoons can be different when they host only a few species, but as species numbers increase, lagoons become homogenous in composition. Multivariate techniques cannot distinguish anthropogenically-impacted lagoons from those, which are naturally disturbed. In the pan-Mediterranean context it is the higher taxonomic levels, but in the national and local context it is the most abundant macrobenthic groups (polychaetes, molluscs and crustaceans) and meiobenthos which provide patterns closest to that derived from the species level. Taxonomic distinctness indices applied to polychaete and mollusc inventories provide meaningful results at most levels and scales of observation. These indices seem to be robust enough to discriminate anthropogenically impacted from naturally disturbed lagoons.     

Immunohistochemical determination of estrogen receptor-α in canine vaginal biopsies throughout proestrus,estrus, and early diestrus

The aim of this study was to describe the presence of estrogen receptor-α (ERα) in several vaginal histological compartments in healthy adult bitches throughout three estrous cycle stages (proestrus, estrus, and early diestrus) and to relate ERα presence with serum progesterone and estradiol-17β concentrations. For this purpose, serial blood samples and vaginal biopsies were taken from five bitches every 48 hours, starting at the clinical onset of proestrus, marked by the beginning of serosanguineous vaginal secretion. Serum progesterone and estradiol-17β concentrations were determined by RIA, whereas detection of steroid receptors was carried out through immunohistochemistry. Subjective image analysis was conducted by two independent observers in the following histological compartments: superficial, intermediate, and deep epithelia and superficial (loose) and deep (dense) stroma (connective tissue). Nuclear ERα immunoreactivity was detected in every histological compartment and estrous cycle stage studied. ERα expression varied among histological compartments and during stages of the cycle. Receptor expression was associated with estradiol-17β and progesterone serum profiles. Most relevant cyclic changes were detected in the superficial and deep epithelia and in the dense connective tissue. The highest ERα expression was detected during diestrus, although each compartment had a different pattern throughout the other cycle stages. Thus, vaginal ERα expression in the bitch varied throughout proestrus, estrus, and early diestrus according to the histological compartment involved.     

Dissecting the Inter-Substrate Navigation of Migrating Glioblastoma Cells with the Stripe Assay Reveals a Causative Role of ROCK

A hallmark of gliomas is the growth and migration of cells over long distances within the brain and proliferation within selected niches, indicating that the migrating cells navigate between complex substrates. We demonstrate in the present study a differential preference for migration that depends on Rho-associated coil kinase (ROCK) signaling, using the alternating Bonhoeffer stripe assay. Membrane fractions from nonmyelinated and myelinated brain areas from female rats, purified myelin also from female rats, and commercial extracellular matrix were used as substrates, with each substrate being tested against the others. The human tumor cell lines exhibited a clear preference for extracellular matrix over all other substrates and for myelinated over nonmyelinated tissue. ROCK signaling was different when cells were cultured on either substrate. The ROCK inhibitor Y27632 significantly attenuated and neutralized the preference for extracellular matrix and myelin, indicating that ROCK controls the substrate selectivity. The findings of this study pave the way for navigation-targeted therapeutics.     

Preparation and Characterization of Lyophilized Liposomes with Incorporated Quercetin

Liposomes composed of egg-phosphatidylcholine (EPC) incorporating quercetin (QR) were prepared by the thin-film hydration method (TFHM) and the monophase solution method (MSM). A rapid and slow freeze-drying process was applied for both laboratory and industrial scales. The purpose of this study was to compare the two methods of liposome preparation, and further determine whether the lyophilization process affects the liposome physicochemical characteristics (size, polydispersity index, and ζ-potential) and incorporation of quercetin.     

Optimization-driven identification of genetic perturbations accelerates the convergence of model parameters in ensemble modeling of metabolic networks

The ensemble modeling (EM) approach has shown promise in capturing kinetic and regulatory effects in the modeling of metabolic networks. Efficacy of the EM procedure relies on the identification of model parameterizations that adequately describe all observed metabolic phenotypes upon perturbation. In this study, we propose an optimization-based algorithm for the systematic identification of genetic/enzyme perturbations to maximally reduce the number of models retained in the ensemble after each round of model screening. The key premise here is to design perturbations that will maximally scatter the predicted steady-state fluxes over the ensemble parameterizations. We demonstrate the applicability of this procedure for an Escherichia coli metabolic model of central metabolism by successively identifying single, double, and triple enzyme perturbations that cause the maximum degree of flux separation between models in the ensemble. Results revealed that optimal perturbations are not always located close to reaction(s) whose fluxes are measured, especially when multiple perturbations are considered. In addition, there appears to be a maximum number of simultaneous perturbations beyond which no appreciable increase in the divergence of flux predictions is achieved. Overall, this study provides a systematic way of optimally designing genetic perturbations for populating the ensemble of models with relevant model parameterizations.