The neuromuscular system of <i>Pycnophyes kielensis</i> (Kinorhyncha: Allomalorhagida) investigated by confocal laser scanning microscopy

Abstract Background Kinorhynchs are ecdysozoan animals with a phylogenetic position close to priapulids and loriciferans. To understand the nature of segmentation within Kinorhyncha and to infer a probable ancestry of segmentation within the last common ancestor of Ecdysozoa, the musculature and the nervous system of the allomalorhagid kinorhynch Pycnophyes kielensis were investigated by use of immunohistochemistry, confocal laser scanning microscopy, and 3D reconstruction software. Results The kinorhynch body plan comprises 11 trunk segments. Trunk musculature consists of paired ventral and dorsal longitudinal muscles in segments 1–10 as well as dorsoventral muscles in segments 1–11. Dorsal and ventral longitudinal muscles insert on apodemes of the cuticle inside the animal within each segment. Strands of longitudinal musculature extend over segment borders in segments 1–6. In segments 7–10, the trunk musculature is confined to the segments. Musculature of the digestive system comprises a strong pharyngeal bulb with attached mouth cone muscles as well as pharyngeal bulb protractors and retractors. The musculature of the digestive system shows no sign of segmentation. Judged by the size of the pharyngeal bulb protractors and retractors, the pharyngeal bulb, as well as the introvert, is moved passively by internal pressure caused by concerted action of the dorsoventral muscles. The nervous system comprises a neuropil ring anterior to the pharyngeal bulb. Associated with the neuropil ring are flask-shaped serotonergic somata extending anteriorly and posteriorly. A ventral nerve cord is connected to the neuropil ring and runs toward the anterior until an attachment point in segment 1, and from there toward the posterior with one ganglion in segment 6. Conclusions Segmentation within Kinorhyncha likely evolved from an unsegmented ancestor. This conclusion is supported by continuous trunk musculature in the anterior segments 1–6, continuous pharyngeal bulb protractors and retractors throughout the anterior segments, no sign of segmentation within the digestive system, and the absence of ganglia in most segments. The musculature shows evidence of segmentation that fit the definition of an anteroposteriorly repeated body unit only in segments 7–10

Comparative larval myogenesis and adult myoanatomy of the rhynchonelliform (articulate) brachiopods Argyrotheca cordata, A. cistellula, and Terebratalia transversa

<p>Abstract</p> <p>Background</p> <p>Despite significant methodological progress, Brachiopoda remains one of the lophotrochozoan phyla for which no recent ontogenetic data employing modern methodologies such as fluorescence labelling and confocal microscopy are available. This is particularly astonishing given the ongoing controversy concerning its phylogenetic position. In order to contribute new morphogenetic data for phylogenetic and evolutionary inferences, we describe herein the ontogeny and myoanatomy of larvae and adults of the rhynchonelliform brachiopods <it>Argyrotheca cordata, A. cistellula</it>, and <it>Terebratalia transversa </it>using fluorescence F-actin labelling combined with confocal laserscanning microscopy.</p> <p>Results</p> <p>Fully grown larvae of <it>A. cordata </it>and <it>T. transversa </it>consist of three distinct body regions, namely an apical lobe, a mantle lobe with four bundles of setae, and a pedicle lobe. Myogenesis is very similar in these two species. The first anlagen of the musculature develop in the pedicle lobe, followed by setae muscles and the mantle lobe musculature. Late-stage larvae show a network of strong pedicle muscles, central mantle muscles, longitudinal muscles running from the mantle to the pedicle lobe, setae pouch muscles, setae muscles, a U-shaped muscle, serial mantle muscles, and apical longitudinal as well as apical transversal muscles. Fully developed <it>A. cistellula </it>larvae differ from the former species in that they have only two visible body lobes and lack setae. Nevertheless, we found corresponding muscle systems to all muscles present in the former two species, except for the musculature associated with the setae, in larvae of <it>A. cistellula</it>. With our survey of the adult myoanatomy of <it>A. cordata </it>and <it>A. cistellula </it>and the juvenile muscular architecture of <it>T. transversa </it>we confirm the presence of adductors, diductors, dorsal and ventral pedicle adjustors, mantle margin muscles, a distinct musculature of the intestine, and striated muscle fibres in the tentacles for all three species.</p> <p>Conclusion</p> <p>Our data indicate that larvae of rhynchonelliform brachiopods share a common muscular bodyplan and are thus derived from a common ancestral larval type. Comparison of the muscular phenotype of rhynchonelliform larvae to that of the other two lophophorate phyla, Phoronida and Ectoprocta, does not indicate homology of individual larval muscles. This may be due to an early evolutionary split of the ontogenetic pathways of Brachiopoda, Phoronida, and Ectoprocta that gave rise to the morphological diversity of these phyla.</p

Testing of Early Ripening Strawberry Cultivars Tolerant to Soil-Borne Pathogens as Alternative to \u27Elsanta\u27

Soil-borne pathogens, above all Verticillium sp., cause plant loss and yield decrease in many Austrian strawberry regions. As part of a research project 13 cultivars were planted in 2005 at 11 sites on nine farms in five different Austrian regions. The aim was to test early ripening Verticillium tolerant cultivars which are winter hardy, with high yield and good fruit characteristics as alternative to the highly susceptible cultivar ‘Elsanta’. Although in 2005 climatic conditions where not favorable for wilt development, ‘Elsanta’, ‘Sonata’, ‘Dora’, ‘Eva’ and ‘Divine’ showed typical symptoms on several sites. ‘Darselect’, ‘Clery’ and ‘Queen Elisa’ were less susceptible than ‘Elsanta’. No indication of wilt on the several sites was observed on ‘Alba’ (except at one site), ‘Alice’, ‘Daroyal’, ‘Record’ and ‘Salsa’. The results of yield and fruit quality have to be interpreted carefully, because they were obtained only at one site in the year of planting. ‘Alba’, ‘Clery’ and ‘Daroyal’ started ripening two days before ‘Elsanta’; ‘Queen Elisa’ and ‘Dora’ at the same day as ‘Elsanta’ and all other cultivars started later. High yield per m2 had ‘Elsanta’, ‘Salsa’, ‘Record’ and ‘Sonata’. High average fruit weight showed ‘Salsa’, ‘Record’ and ‘Darselect’, while ‘Divine’, ‘Clery’ and ‘Queen Elisa’ had rather small fruits. Some new cultivars (e.g. ‘Eva’, ‘Queen Elisa’, ‘Alba’ and ‘Record’) had a much higher fruit firmness in comparison to ‘Elsanta’; nevertheless this was not favourable in the tasting experiment. Further examinations are planned in future

Teaching plant-animal interactions with active student participation and deep learning

Teachers can improve their performance and thus students’ learning outcome through systematic reflection on their teaching (Sølberg, 2015). And teaching and learning can be improved by adding variation in teaching methods and learning activities (Weimer, 1990). This paper reports the results of a didactical research project and is a reflection on planning and teachinga three-hour session for master students in the course ‘Plant Animal Interactions. An Evolutionary Approach’ in the fall semester 2016 at the University of Copenhagen. I used recommendations described by Peter Stray Jørgensen (Jørgensen, 2015) and Donald A. Bligh (Bligh, 2000) to plan the session. The aim of the research project was to identify teaching methods that improve the student learning outcome of my teaching. I did this by adding five diverse learning activities throughout the session (lectures, microscopy, student experiment, experiment analysis, and presentation of experiment results). The students evaluated the perceived effectiveness of each learning activity immediately after the session in a questionnaire

First Evidence of the Toxin Domoic Acid in Antarctic Diatom Species

The Southern Ocean is one of the most productive ecosystems in the world. It is an area heavily dependent on marine primary production and serving as a feeding ground for numerous seabirds and marine mammals. Therefore, the phytoplankton composition and presence of toxic species are of crucial importance. Fifteen monoclonal strains of Pseudo-nitzschia subcurvata, a diatom species endemic to the Southern Ocean, were established, which were characterized by morphological and molecular data and then analysed for toxin content. The neurotoxins domoic acid and iso-domoic acid C were present in three of the strains, which is a finding that represents the first evidence of these toxins in strains from Antarctic waters. Toxic phytoplankton in Antarctic waters are still largely unexplored, and their effects on the ecosystem are not well understood. Considering P. subcurvata’s prevalence throughout the Southern Ocean, these results highlight the need for further investigations of the harmful properties on the Antarctic phytoplankton community as well as the presence of the toxins in the Antarctic food web, especially in the light of a changing climate

Konzeptionelle Anforderungen an Gruppenunterstützung für verteilte internetbasierte Führungsinformationssysteme

Führungsinformationssysteme (FIS) wurden ursprünglich als Einzelplatzsysteme entwickelt. Aus unterschiedlichen Gründen werden Führungsentscheidungen jedoch immer öfter von einer Gruppe von Entscheidungsträgern getroffen. Daher wird ein Konzept eines FIS vorgestellt und die Konzeption um Gruppenunterstützungskomponenten erweitert. Ein Anforderungskatalog, der an den speziellen Nutzerkreis eines FIS angepaßt ist, wird entwickelt und kann zur systematischen Bewertung von Gruppenunterstützungswerkzeugen benutzt werden kann.Executive Information Systems (EIS) used to be designed as single-user systems. For several reasons, an increasing number of executive-decisions are made by groups of executives. After introducing a concept of a EIS, the concept is improved by appending group support components. A catalogue of requirements, adapted for the user characteristics of EIS, is developed. This catalogue may be used for systematic evaluation of group support systems