(n-3) HUFA composition of freshly spawned eggs from European seabass (<i>Dicentrarchus labrax</i>), seabream (<i>Sparus aurata</i>) and red seabream (<i>Pagrus major</i>) collected in different hatcheries

The biochemical composition of fish eggs is often used as an indicator for assessing the nutritional requirements of aquaculture species during their larval stages. Fatty acids of the (n-3) HUFA type have proven to play a critical role in providing good growth, survival and stress resistance in marine fish larvae. Hence, analyzing these fatty acids in fish eggs may provide interesting data on the requirements for those essential nutrients. By comparing the analyses of wild versus broodstock fish eggs differences may appear, possibly explaining differences in egg quality. Intra-spawning-season differences may further appear by following fatty acid profiles in the course of time. Finally, the influence of broodstock nutritionon egg composition may be another variable to consider in the evaluation of the above. In this study freshly released eggs of European seabass (Dicentrarchus labrax), seabream (Sparus aurata), and red seabream (Pagrus major) were collected from broodstock fish held under different conditions in various hatcheries. Temporal variations in fatty acid profiles were monitored by following a seabream broodstock during 1 month. The effect of feedig broodstock with fish-oil coated pellets on the fatty acid profiles of the eggs produced, was established for seabream. The results indicate that for the three species the content of 22:6n-3 is considerably higher than 20:5n-3. Total (n-3) HUFA on dry weight basis appears highest in seabass while on a relative basis (% of total fatty acids) the highest levels are found in seabream eggs and the lowest in red seabream. Differences between seabass eggs from females caught in the wild and naturally spawned broodstock fish kept in captivity, occur particularly in the lower content (half) of 22:6n-3 in the wild eggs. Differenes within the same species cultured at different locations and hence under different conditions are insignificant. The variability is in the range of 2.9 to 9.3% for the relative values and 8.6 to 18.9% for the absolute figures

Immunolocalization of dually phosphorylated MAPKs in dividing root meristem cells of Vicia faba, Pisum sativum, Lupinus luteus and Lycopersicon esculentum

Key message In plants, phosphorylated MAPKs display constitutive nuclear localization; however, not all studied plant species show co-localization of activated MAPKs to mitotic microtubules. Abstract The mitogen-activated protein kinase (MAPK) signaling pathway is involved not only in the cellular response to biotic and abiotic stress but also in the regulation of cell cycle and plant development. The role of MAPKs in the formation of a mitotic spindle has been widely studied and the MAPK signaling pathway was found to be indispensable for the unperturbed course of cell division. Here we show cellular localization of activated MAPKs (dually phosphorylated at their TXY motifs) in both interphase and mitotic root meristem cells of Lupinus luteus, Pisum sativum, Vicia faba (Fabaceae) and Lycopersicon esculentum (Solanaceae). Nuclear localization of activated MAPKs has been found in all species. Colocalization of these kinases to mitotic microtubules was most evident in L. esculentum, while only about 50 % of mitotic cells in the root meristems of P. sativum and V. faba displayed activated MAPKs localized to microtubules during mitosis. Unexpectedly, no evident immunofluorescence signals at spindle microtubules and phragmoplast were noted in L. luteus. Considering immunocytochemical analyses and studies on the impact of FR180204 (an inhibitor of animal ERK1/2) on mitotic cells, we hypothesize that MAPKs may not play prominent role in the regulation of microtubule dynamics in all plant species

Strategic and practical guidelines for successful structured illumination microscopy

Linear 2D- or 3D-structured illumination microscopy (SIM or3D-SIM, respectively) enables multicolor volumetric imaging of fixed and live specimens with subdiffraction resolution in all spatial dimensions. However, the reliance of SIM on algorithmic post-processing renders it particularly sensitive to artifacts that may reduce resolution, compromise data and its interpretations, and drain resources in terms of money and time spent. Here we present a protocol that allows users to generate high-quality SIM data while accounting and correcting for common artifacts. The protocol details preparation of calibration bead slides designed for SIM-based experiments, the acquisition of calibration data, the documentation of typically encountered SIM artifacts and corrective measures that should be taken to reduce them. It also includes a conceptual overview and checklist for experimental design and calibration decisions, and is applicable to any commercially available or custom platform. This protocol, plus accompanying guidelines, allows researchers from students to imaging professionals to create an optimal SIM imaging environment regardless of specimen type or structure of interest. The calibration sample preparation and system calibration protocol can be executed within 1-2 d

A Bacterial Acetyltransferase Destroys Plant Microtubule Networks and Blocks Secretion

The eukaryotic cytoskeleton is essential for structural support and intracellular transport, and is therefore a common target of animal pathogens. However, no phytopathogenic effector has yet been demonstrated to specifically target the plant cytoskeleton. Here we show that the Pseudomonas syringae type III secreted effector HopZ1a interacts with tubulin and polymerized microtubules. We demonstrate that HopZ1a is an acetyltransferase activated by the eukaryotic co-factor phytic acid. Activated HopZ1a acetylates itself and tubulin. The conserved autoacetylation site of the YopJ / HopZ superfamily, K289, plays a critical role in both the avirulence and virulence function of HopZ1a. Furthermore, HopZ1a requires its acetyltransferase activity to cause a dramatic decrease in Arabidopsis thaliana microtubule networks, disrupt the plant secretory pathway and suppress cell wall-mediated defense. Together, this study supports the hypothesis that HopZ1a promotes virulence through cytoskeletal and secretory disruption

Collaborative Problem Solving using an Open Modeling Environment

This paper presents ModelsCreator version 3 (MC3) an environment that supports collaborative building of various kinds of models. MC3 is an environment that permits synchronous interaction of students at a distance who collaborate in building models out of primitive objects. The open character of MC3 means that students have access to an open set of primitive objects that can be used for building these models. A result of this characteristic is that the collaborating partners may reason using heterogeneous sets of primitive objects, in order to obtain a solution. In this paper we concentrate on the architecture of MC3 and the basic functionality of the environment. In particular we study the effect of the open character of the environment in collaboration and problem solving. Through experimentation it is demonstrated that the users of MC3 can have rich interaction in order to build or exchange at run time the necessary primitive objects for model building