The Evolution of Gap Gene Orthologues

Die Segmentierung in der Fliege Drosophila melanogaster ist weitgehend verstanden. Als sogenannter "Langkeimer" entwickelt sich die Fliege jedoch anders als die meisten anderen Insekten: Bei der Fliege entstehen alle Segmente auf einmal im Blastoderm. Im Mehlkäfer Tribolium castaneum und den meisten anderen Insekten entstehen in diesem Stadium aber nur die vorderen Segmente, während die abdominales Segmente nacheinander von einer posterioren Wachstumszone gebildet werden. Um die Unterschiede in der abdominalen Segmentierung zu untersuchen, wurde das Homolog des abdominalen Gapgens "giant" aus dem Mehlkäfer "Tribolium castaneum" isoliert und seine Funktion beschrieben. Mehrere fundamentale Unterschiede zu "Drosophila giant" wurden deutlich: 1) die Expression von Tribolium giant ist 5 Segmente weiter anterior 2) die Funktion des Gens kann nicht auf dem Aufbau eines kurzreichweitigen Gradienten beruhen (dem aus Drosophila beschriebenen "klassischen" Gapgen-Mechanismus). Zusammen zeigen die Ergebnisse, dass dass die Segmentierung im Abdomen des Käfers anders funktioniert als in der Fliege

Changes in anterior head patterning underlie the evolution of long germ embryogenesis

AbstractEarly embryonic stages differ significantly among related animal taxa while subsequent development converges at the conserved phylotypic stage before again diverging. Although this phenomenon has long been observed, its underlying genetic mechanisms remain enigmatic. The dipteran Drosophila melanogaster develops as a long germ embryo where the head anlagen form a cap at the anterior pole of the blastoderm. Consequently, the anterior and terminal maternal systems give crucial input for head patterning. However, in the short germ beetle Tribolium castaneum, as in most insects, the head anlagen is located at a ventral position distant from the anterior pole of the blastoderm. In line with these divergent embryonic anlagen, several differences in the axis formation between the insects have been discovered. We now ask to what extent patterning and morphogenesis of the anterior median region (AMR) of the head, including clypeolabral and stomodeal anlagen, differ among these insects. Unexpectedly, we find that Tc-huckebein is not a terminal gap gene and, unlike its Drosophila ortholog, is not involved in Tribolium head development. Instead, Tc-six3 acts upstream of Tc-crocodile and Tc-cap'n'collar to pattern posterior and anterior parts of the AMR, respectively. We further find that instead of huckebein, Tc-crocodile is required for stomodeum development by activating Tc-forkhead. Finally, a morphogenetic movement not found in Drosophila shapes the embryonic head of Tribolium. Apparently, with anterior displacement of the head anlagen during long germ evolution of Drosophila, the ancestral regulation by the bilaterian anterior control gene six3 was replaced by the anterior and terminal maternal systems, which were further elaborated by adding bicoid, tailless and huckebein as anterior regionalization genes

Exploring systemic RNA interference in insects: a genome-wide survey for RNAi genes in Tribolium

Tribolium resembles C. elegans in showing a robust systemic RNAi response, but does not have C. elegans-type RNAi mechanisms; insect systemic RNAi probably uses a different mechanism

Large-scale insertional mutagenesis of a coleopteran stored grain pest, the red flour beetle Tribolium castaneum, identifies embryonic lethal mutations and enhancer traps

<p>Abstract</p> <p>Background</p> <p>Given its sequenced genome and efficient systemic RNA interference response, the red flour beetle <it>Tribolium castaneum </it>is a model organism well suited for reverse genetics. Even so, there is a pressing need for forward genetic analysis to escape the bias inherent in candidate gene approaches.</p> <p>Results</p> <p>To produce easy-to-maintain insertional mutations and to obtain fluorescent marker lines to aid phenotypic analysis, we undertook a large-scale transposon mutagenesis screen. In this screen, we produced more than 6,500 new <it>piggyBac </it>insertions. Of these, 421 proved to be recessive lethal, 75 were semi-lethal, and eight indicated recessive sterility, while 505 showed new enhancer-trap patterns. Insertion junctions were determined for 403 lines and often appeared to be located within transcription units. Insertion sites appeared to be randomly distributed throughout the genome, with the exception of a preference for reinsertion near the donor site.</p> <p>Conclusion</p> <p>A large collection of enhancer-trap and embryonic lethal beetle lines has been made available to the research community and will foster investigations into diverse fields of insect biology, pest control, and evolution. Because the genetic elements used in this screen are species-nonspecific, and because the crossing scheme does not depend on balancer chromosomes, the methods presented herein should be broadly applicable for many insect species.</p

Human metapneumovirus infection after allogeneic hematopoietic stem cell transplantation

Background: The clinical characteristics of human metapneumovirus (hMPV)-associated lower respiratory tract infection (LRTI) after allogeneic hematopoietic stem cell transplantation (HSCT) is not well described. We describe the clinical course in eight HSCT recipients suffering from hMPV infection. Methods: We prospectively included all patients with hMPV-associated LRTI after allogeneic HSCT during a period of 1year. hMPV was diagnosed by multiplex polymerase chain reaction (PCR) from bronchoalveolar lavage (BAL). Results: Eight patients with hMPV-associated LRTI were identified from 93 BAL samples. Three of the eight patients had co-infections with other pathogens. The median age of the patients was 45years [interquartile range (IQR) 36.8-53.5], the median time posttransplant was 473days (IQR 251-1,165), 5/8 patients had chronic graft-versus-host disease (cGvHD), and 6/8 patients received immunosuppression. Chest computed tomography (CT) scanning showed a ground-glass pattern in 7/8 patients. Seven of eight patients required hospitalization due to severe symptoms and hypoxemia. All were treated with intravenous immunoglobulin (IVIG), which was combined with oral ribavirin in six patients. The mortality rate was 12.5% (1/8). Conclusions: hMPV-associated LRTI in allogeneic HSCT recipients are not uncommon and present with unspecific respiratory symptoms, ground-glass pattern in CT scanning, and co-infectio

Whole-mount in situ hybridization in the Rotifer Brachionus plicatilis representing a basal branch of lophotrochozoans

In order to broaden the comparative scope of evolutionary developmental biology and to refine our picture of animal macroevolution, it is necessary to establish new model organisms, especially from previously underrepresented groups, like the Lophotrochozoa. We have established the culture and protocols for molecular developmental biology in the rotifer species Brachionus plicatilis Müller (Rotifera, Monogononta). Rotifers are nonsegmented animals with enigmatic basal position within the lophotrochozoans and marked by several evolutionary novelties like the wheel organ (corona), the median eye, and the nonpaired posterior foot. The expression of Bp-Pax-6 is shown using whole-mount in situ hybridization. The inexpensive easy culture and experimental tractability of Brachionus as well as the range of interesting questions to which it holds the key make it a promising addition to the “zoo” of evo-devo model organisms

Insertional mutagenesis screening identifies the zinc finger homeodomain 2 (zfh2) gene as a novel factor required for embryonic leg development in Tribolium castaneum

The genetic control of leg development is well characterized in the fly Drosophila melanogaster. These control mechanisms, however, must differ to some degree between different insect species to account for the morphological diversity of thoracic legs in the insects. The legs of the flour beetle Tribolium castaneum differ from the Drosophila legs in their developmental mode as well as in their specific morphology especially at the larval stage. In order to identify genes involved in the morphogenesis of the Tribolium larval legs, we have analyzed EGFP enhancer trap lines of Tribolium. We have identified the zfh2 gene as a novel factor required for normal leg development in Tribolium. RNA interference with zfh2 function leads to two alternative classes of leg phenotype. The loss of a leg segment boundary and the generation of ectopic outgrowths in one class of phenotype suggest a role in leg segmentation and segment growth. The malformation of the pretarsal claw in the second class of phenotype suggests a role in distal development and the morphogenesis of the claw-shaped morphology of the pretarsus. This suggests that zfh2 is involved in the regulation of an unidentified target gene in a concentration-dependent manner. Our results demonstrate that enhancer trap screens in T. castaneum have the potential to identify novel gene functions regulating specific developmental processes

TRY plant trait database - enhanced coverage and open access

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

How to Exploit the Digitalization Potential of Business Processes

Process improvement is the most value-adding activity in the business process management (BPM) lifecycle. Despite mature knowledge, many approaches have been criticized to lack guidance on how to put process improvement into practice. Given the variety of emerging digital technologies, organizations not only face a process improvement black box, but also high uncertainty regarding digital technologies. This paper thus proposes a method that supports organizations in exploiting the digitalization potential of their business processes. To achieve this, action design research and situational method engineering were adopted. Two design cycles involving practitioners (i.e., managers and BPM experts) and end-users (i.e., process owners and participants) were conducted. In the first cycle, the method’s alpha version was evaluated by interviewing practitioners from five organizations. In the second cycle, the beta version was evaluated via real-world case studies. In this paper, detailed results of one case study, which was conducted at a semiconductor manufacturer, are included